1 /*
   2  * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 // no precompiled headers
  26 #include "classfile/classLoader.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "classfile/vmSymbols.hpp"
  29 #include "code/icBuffer.hpp"
  30 #include "code/vtableStubs.hpp"
  31 #include "compiler/compileBroker.hpp"
  32 #include "compiler/disassembler.hpp"
  33 #include "interpreter/interpreter.hpp"
  34 #include "jvm_bsd.h"
  35 #include "memory/allocation.inline.hpp"
  36 #include "memory/filemap.hpp"
  37 #include "mutex_bsd.inline.hpp"
  38 #include "oops/oop.inline.hpp"
  39 #include "os_share_bsd.hpp"
  40 #include "prims/jniFastGetField.hpp"
  41 #include "prims/jvm.h"
  42 #include "prims/jvm_misc.hpp"
  43 #include "runtime/arguments.hpp"
  44 #include "runtime/extendedPC.hpp"
  45 #include "runtime/globals.hpp"
  46 #include "runtime/interfaceSupport.hpp"
  47 #include "runtime/java.hpp"
  48 #include "runtime/javaCalls.hpp"
  49 #include "runtime/mutexLocker.hpp"
  50 #include "runtime/objectMonitor.hpp"
  51 #include "runtime/orderAccess.inline.hpp"
  52 #include "runtime/osThread.hpp"
  53 #include "runtime/perfMemory.hpp"
  54 #include "runtime/sharedRuntime.hpp"
  55 #include "runtime/statSampler.hpp"
  56 #include "runtime/stubRoutines.hpp"
  57 #include "runtime/thread.inline.hpp"
  58 #include "runtime/threadCritical.hpp"
  59 #include "runtime/timer.hpp"
  60 #include "services/attachListener.hpp"
  61 #include "services/memTracker.hpp"
  62 #include "services/runtimeService.hpp"
  63 #include "utilities/decoder.hpp"
  64 #include "utilities/defaultStream.hpp"
  65 #include "utilities/events.hpp"
  66 #include "utilities/growableArray.hpp"
  67 #include "utilities/vmError.hpp"
  68 
  69 // put OS-includes here
  70 # include <sys/types.h>
  71 # include <sys/mman.h>
  72 # include <sys/stat.h>
  73 # include <sys/select.h>
  74 # include <pthread.h>
  75 # include <signal.h>
  76 # include <errno.h>
  77 # include <dlfcn.h>
  78 # include <stdio.h>
  79 # include <unistd.h>
  80 # include <sys/resource.h>
  81 # include <pthread.h>
  82 # include <sys/stat.h>
  83 # include <sys/time.h>
  84 # include <sys/times.h>
  85 # include <sys/utsname.h>
  86 # include <sys/socket.h>
  87 # include <sys/wait.h>
  88 # include <time.h>
  89 # include <pwd.h>
  90 # include <poll.h>
  91 # include <semaphore.h>
  92 # include <fcntl.h>
  93 # include <string.h>
  94 # include <sys/param.h>
  95 # include <sys/sysctl.h>
  96 # include <sys/ipc.h>
  97 # include <sys/shm.h>
  98 #ifndef __APPLE__
  99 # include <link.h>
 100 #endif
 101 # include <stdint.h>
 102 # include <inttypes.h>
 103 # include <sys/ioctl.h>
 104 # include <sys/syscall.h>
 105 
 106 #if defined(__FreeBSD__) || defined(__NetBSD__)
 107 # include <elf.h>
 108 #endif
 109 
 110 #ifdef __APPLE__
 111 # include <mach/mach.h> // semaphore_* API
 112 # include <mach-o/dyld.h>
 113 # include <sys/proc_info.h>
 114 # include <objc/objc-auto.h>
 115 #endif
 116 
 117 #ifndef MAP_ANONYMOUS
 118 #define MAP_ANONYMOUS MAP_ANON
 119 #endif
 120 
 121 #define MAX_PATH    (2 * K)
 122 
 123 // for timer info max values which include all bits
 124 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
 125 
 126 #define LARGEPAGES_BIT (1 << 6)
 127 
 128 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
 129 
 130 ////////////////////////////////////////////////////////////////////////////////
 131 // global variables
 132 julong os::Bsd::_physical_memory = 0;
 133 
 134 #ifdef __APPLE__
 135 mach_timebase_info_data_t os::Bsd::_timebase_info = {0, 0};
 136 volatile uint64_t         os::Bsd::_max_abstime   = 0;
 137 #else
 138 int (*os::Bsd::_clock_gettime)(clockid_t, struct timespec *) = NULL;
 139 #endif
 140 pthread_t os::Bsd::_main_thread;
 141 int os::Bsd::_page_size = -1;
 142 
 143 static jlong initial_time_count=0;
 144 
 145 static int clock_tics_per_sec = 100;
 146 
 147 // For diagnostics to print a message once. see run_periodic_checks
 148 static sigset_t check_signal_done;
 149 static bool check_signals = true;
 150 
 151 static pid_t _initial_pid = 0;
 152 
 153 /* Signal number used to suspend/resume a thread */
 154 
 155 /* do not use any signal number less than SIGSEGV, see 4355769 */
 156 static int SR_signum = SIGUSR2;
 157 sigset_t SR_sigset;
 158 
 159 
 160 ////////////////////////////////////////////////////////////////////////////////
 161 // utility functions
 162 
 163 static int SR_initialize();
 164 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
 165 
 166 julong os::available_memory() {
 167   return Bsd::available_memory();
 168 }
 169 
 170 // available here means free
 171 julong os::Bsd::available_memory() {
 172   uint64_t available = physical_memory() >> 2;
 173 #ifdef __APPLE__
 174   mach_msg_type_number_t count = HOST_VM_INFO64_COUNT;
 175   vm_statistics64_data_t vmstat;
 176   kern_return_t kerr = host_statistics64(mach_host_self(), HOST_VM_INFO64,
 177                                          (host_info64_t)&vmstat, &count);
 178   assert(kerr == KERN_SUCCESS,
 179          "host_statistics64 failed - check mach_host_self() and count");
 180   if (kerr == KERN_SUCCESS) {
 181     available = vmstat.free_count * os::vm_page_size();
 182   }
 183 #endif
 184   return available;
 185 }
 186 
 187 julong os::physical_memory() {
 188   return Bsd::physical_memory();
 189 }
 190 
 191 ////////////////////////////////////////////////////////////////////////////////
 192 // environment support
 193 
 194 bool os::getenv(const char* name, char* buf, int len) {
 195   const char* val = ::getenv(name);
 196   if (val != NULL && strlen(val) < (size_t)len) {
 197     strcpy(buf, val);
 198     return true;
 199   }
 200   if (len > 0) buf[0] = 0;  // return a null string
 201   return false;
 202 }
 203 
 204 
 205 // Return true if user is running as root.
 206 
 207 bool os::have_special_privileges() {
 208   static bool init = false;
 209   static bool privileges = false;
 210   if (!init) {
 211     privileges = (getuid() != geteuid()) || (getgid() != getegid());
 212     init = true;
 213   }
 214   return privileges;
 215 }
 216 
 217 
 218 
 219 // Cpu architecture string
 220 #if   defined(ZERO)
 221 static char cpu_arch[] = ZERO_LIBARCH;
 222 #elif defined(IA64)
 223 static char cpu_arch[] = "ia64";
 224 #elif defined(IA32)
 225 static char cpu_arch[] = "i386";
 226 #elif defined(AMD64)
 227 static char cpu_arch[] = "amd64";
 228 #elif defined(ARM)
 229 static char cpu_arch[] = "arm";
 230 #elif defined(PPC32)
 231 static char cpu_arch[] = "ppc";
 232 #elif defined(SPARC)
 233 #  ifdef _LP64
 234 static char cpu_arch[] = "sparcv9";
 235 #  else
 236 static char cpu_arch[] = "sparc";
 237 #  endif
 238 #else
 239 #error Add appropriate cpu_arch setting
 240 #endif
 241 
 242 // Compiler variant
 243 #ifdef COMPILER2
 244 #define COMPILER_VARIANT "server"
 245 #else
 246 #define COMPILER_VARIANT "client"
 247 #endif
 248 
 249 
 250 void os::Bsd::initialize_system_info() {
 251   int mib[2];
 252   size_t len;
 253   int cpu_val;
 254   julong mem_val;
 255 
 256   /* get processors count via hw.ncpus sysctl */
 257   mib[0] = CTL_HW;
 258   mib[1] = HW_NCPU;
 259   len = sizeof(cpu_val);
 260   if (sysctl(mib, 2, &cpu_val, &len, NULL, 0) != -1 && cpu_val >= 1) {
 261        assert(len == sizeof(cpu_val), "unexpected data size");
 262        set_processor_count(cpu_val);
 263   }
 264   else {
 265        set_processor_count(1);   // fallback
 266   }
 267 
 268   /* get physical memory via hw.memsize sysctl (hw.memsize is used
 269    * since it returns a 64 bit value)
 270    */
 271   mib[0] = CTL_HW;
 272 
 273 #if defined (HW_MEMSIZE) // Apple
 274   mib[1] = HW_MEMSIZE;
 275 #elif defined(HW_PHYSMEM) // Most of BSD
 276   mib[1] = HW_PHYSMEM;
 277 #elif defined(HW_REALMEM) // Old FreeBSD
 278   mib[1] = HW_REALMEM;
 279 #else
 280   #error No ways to get physmem
 281 #endif
 282 
 283   len = sizeof(mem_val);
 284   if (sysctl(mib, 2, &mem_val, &len, NULL, 0) != -1) {
 285        assert(len == sizeof(mem_val), "unexpected data size");
 286        _physical_memory = mem_val;
 287   } else {
 288        _physical_memory = 256*1024*1024;       // fallback (XXXBSD?)
 289   }
 290 
 291 #ifdef __OpenBSD__
 292   {
 293        // limit _physical_memory memory view on OpenBSD since
 294        // datasize rlimit restricts us anyway.
 295        struct rlimit limits;
 296        getrlimit(RLIMIT_DATA, &limits);
 297        _physical_memory = MIN2(_physical_memory, (julong)limits.rlim_cur);
 298   }
 299 #endif
 300 }
 301 
 302 #ifdef __APPLE__
 303 static const char *get_home() {
 304   const char *home_dir = ::getenv("HOME");
 305   if ((home_dir == NULL) || (*home_dir == '\0')) {
 306     struct passwd *passwd_info = getpwuid(geteuid());
 307     if (passwd_info != NULL) {
 308       home_dir = passwd_info->pw_dir;
 309     }
 310   }
 311 
 312   return home_dir;
 313 }
 314 #endif
 315 
 316 void os::init_system_properties_values() {
 317   // The next steps are taken in the product version:
 318   //
 319   // Obtain the JAVA_HOME value from the location of libjvm.so.
 320   // This library should be located at:
 321   // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm.so.
 322   //
 323   // If "/jre/lib/" appears at the right place in the path, then we
 324   // assume libjvm.so is installed in a JDK and we use this path.
 325   //
 326   // Otherwise exit with message: "Could not create the Java virtual machine."
 327   //
 328   // The following extra steps are taken in the debugging version:
 329   //
 330   // If "/jre/lib/" does NOT appear at the right place in the path
 331   // instead of exit check for $JAVA_HOME environment variable.
 332   //
 333   // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
 334   // then we append a fake suffix "hotspot/libjvm.so" to this path so
 335   // it looks like libjvm.so is installed there
 336   // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm.so.
 337   //
 338   // Otherwise exit.
 339   //
 340   // Important note: if the location of libjvm.so changes this
 341   // code needs to be changed accordingly.
 342 
 343 // See ld(1):
 344 //      The linker uses the following search paths to locate required
 345 //      shared libraries:
 346 //        1: ...
 347 //        ...
 348 //        7: The default directories, normally /lib and /usr/lib.
 349 #ifndef DEFAULT_LIBPATH
 350 #define DEFAULT_LIBPATH "/lib:/usr/lib"
 351 #endif
 352 
 353 // Base path of extensions installed on the system.
 354 #define SYS_EXT_DIR     "/usr/java/packages"
 355 #define EXTENSIONS_DIR  "/lib/ext"
 356 #define ENDORSED_DIR    "/lib/endorsed"
 357 
 358 #ifndef __APPLE__
 359 
 360   // Buffer that fits several sprintfs.
 361   // Note that the space for the colon and the trailing null are provided
 362   // by the nulls included by the sizeof operator.
 363   const size_t bufsize =
 364     MAX3((size_t)MAXPATHLEN,  // For dll_dir & friends.
 365          (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + sizeof(SYS_EXT_DIR) + sizeof(EXTENSIONS_DIR), // extensions dir
 366          (size_t)MAXPATHLEN + sizeof(ENDORSED_DIR)); // endorsed dir
 367   char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
 368 
 369   // sysclasspath, java_home, dll_dir
 370   {
 371     char *pslash;
 372     os::jvm_path(buf, bufsize);
 373 
 374     // Found the full path to libjvm.so.
 375     // Now cut the path to <java_home>/jre if we can.
 376     *(strrchr(buf, '/')) = '\0'; // Get rid of /libjvm.so.
 377     pslash = strrchr(buf, '/');
 378     if (pslash != NULL) {
 379       *pslash = '\0';            // Get rid of /{client|server|hotspot}.
 380     }
 381     Arguments::set_dll_dir(buf);
 382 
 383     if (pslash != NULL) {
 384       pslash = strrchr(buf, '/');
 385       if (pslash != NULL) {
 386         *pslash = '\0';          // Get rid of /<arch>.
 387         pslash = strrchr(buf, '/');
 388         if (pslash != NULL) {
 389           *pslash = '\0';        // Get rid of /lib.
 390         }
 391       }
 392     }
 393     Arguments::set_java_home(buf);
 394     set_boot_path('/', ':');
 395   }
 396 
 397   // Where to look for native libraries.
 398   //
 399   // Note: Due to a legacy implementation, most of the library path
 400   // is set in the launcher. This was to accomodate linking restrictions
 401   // on legacy Bsd implementations (which are no longer supported).
 402   // Eventually, all the library path setting will be done here.
 403   //
 404   // However, to prevent the proliferation of improperly built native
 405   // libraries, the new path component /usr/java/packages is added here.
 406   // Eventually, all the library path setting will be done here.
 407   {
 408     // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
 409     // should always exist (until the legacy problem cited above is
 410     // addressed).
 411     const char *v = ::getenv("LD_LIBRARY_PATH");
 412     const char *v_colon = ":";
 413     if (v == NULL) { v = ""; v_colon = ""; }
 414     // That's +1 for the colon and +1 for the trailing '\0'.
 415     char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
 416                                                      strlen(v) + 1 +
 417                                                      sizeof(SYS_EXT_DIR) + sizeof("/lib/") + strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH) + 1,
 418                                                      mtInternal);
 419     sprintf(ld_library_path, "%s%s" SYS_EXT_DIR "/lib/%s:" DEFAULT_LIBPATH, v, v_colon, cpu_arch);
 420     Arguments::set_library_path(ld_library_path);
 421     FREE_C_HEAP_ARRAY(char, ld_library_path, mtInternal);
 422   }
 423 
 424   // Extensions directories.
 425   sprintf(buf, "%s" EXTENSIONS_DIR ":" SYS_EXT_DIR EXTENSIONS_DIR, Arguments::get_java_home());
 426   Arguments::set_ext_dirs(buf);
 427 
 428   // Endorsed standards default directory.
 429   sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
 430   Arguments::set_endorsed_dirs(buf);
 431 
 432   FREE_C_HEAP_ARRAY(char, buf, mtInternal);
 433 
 434 #else // __APPLE__
 435 
 436 #define SYS_EXTENSIONS_DIR   "/Library/Java/Extensions"
 437 #define SYS_EXTENSIONS_DIRS  SYS_EXTENSIONS_DIR ":/Network" SYS_EXTENSIONS_DIR ":/System" SYS_EXTENSIONS_DIR ":/usr/lib/java"
 438 
 439   const char *user_home_dir = get_home();
 440   // The null in SYS_EXTENSIONS_DIRS counts for the size of the colon after user_home_dir.
 441   size_t system_ext_size = strlen(user_home_dir) + sizeof(SYS_EXTENSIONS_DIR) +
 442     sizeof(SYS_EXTENSIONS_DIRS);
 443 
 444   // Buffer that fits several sprintfs.
 445   // Note that the space for the colon and the trailing null are provided
 446   // by the nulls included by the sizeof operator.
 447   const size_t bufsize =
 448     MAX3((size_t)MAXPATHLEN,  // for dll_dir & friends.
 449          (size_t)MAXPATHLEN + sizeof(EXTENSIONS_DIR) + system_ext_size, // extensions dir
 450          (size_t)MAXPATHLEN + sizeof(ENDORSED_DIR)); // endorsed dir
 451   char *buf = (char *)NEW_C_HEAP_ARRAY(char, bufsize, mtInternal);
 452 
 453   // sysclasspath, java_home, dll_dir
 454   {
 455     char *pslash;
 456     os::jvm_path(buf, bufsize);
 457 
 458     // Found the full path to libjvm.so.
 459     // Now cut the path to <java_home>/jre if we can.
 460     *(strrchr(buf, '/')) = '\0'; // Get rid of /libjvm.so.
 461     pslash = strrchr(buf, '/');
 462     if (pslash != NULL) {
 463       *pslash = '\0';            // Get rid of /{client|server|hotspot}.
 464     }
 465     Arguments::set_dll_dir(buf);
 466 
 467     if (pslash != NULL) {
 468       pslash = strrchr(buf, '/');
 469       if (pslash != NULL) {
 470         *pslash = '\0';          // Get rid of /lib.
 471       }
 472     }
 473     Arguments::set_java_home(buf);
 474     set_boot_path('/', ':');
 475   }
 476 
 477   // Where to look for native libraries.
 478   //
 479   // Note: Due to a legacy implementation, most of the library path
 480   // is set in the launcher. This was to accomodate linking restrictions
 481   // on legacy Bsd implementations (which are no longer supported).
 482   // Eventually, all the library path setting will be done here.
 483   //
 484   // However, to prevent the proliferation of improperly built native
 485   // libraries, the new path component /usr/java/packages is added here.
 486   // Eventually, all the library path setting will be done here.
 487   {
 488     // Get the user setting of LD_LIBRARY_PATH, and prepended it. It
 489     // should always exist (until the legacy problem cited above is
 490     // addressed).
 491     // Prepend the default path with the JAVA_LIBRARY_PATH so that the app launcher code
 492     // can specify a directory inside an app wrapper
 493     const char *l = ::getenv("JAVA_LIBRARY_PATH");
 494     const char *l_colon = ":";
 495     if (l == NULL) { l = ""; l_colon = ""; }
 496 
 497     const char *v = ::getenv("DYLD_LIBRARY_PATH");
 498     const char *v_colon = ":";
 499     if (v == NULL) { v = ""; v_colon = ""; }
 500 
 501     // Apple's Java6 has "." at the beginning of java.library.path.
 502     // OpenJDK on Windows has "." at the end of java.library.path.
 503     // OpenJDK on Linux and Solaris don't have "." in java.library.path
 504     // at all. To ease the transition from Apple's Java6 to OpenJDK7,
 505     // "." is appended to the end of java.library.path. Yes, this
 506     // could cause a change in behavior, but Apple's Java6 behavior
 507     // can be achieved by putting "." at the beginning of the
 508     // JAVA_LIBRARY_PATH environment variable.
 509     char *ld_library_path = (char *)NEW_C_HEAP_ARRAY(char,
 510                                                      strlen(v) + 1 + strlen(l) + 1 +
 511                                                      system_ext_size + 3,
 512                                                      mtInternal);
 513     sprintf(ld_library_path, "%s%s%s%s%s" SYS_EXTENSIONS_DIR ":" SYS_EXTENSIONS_DIRS ":.",
 514             v, v_colon, l, l_colon, user_home_dir);
 515     Arguments::set_library_path(ld_library_path);
 516     FREE_C_HEAP_ARRAY(char, ld_library_path, mtInternal);
 517   }
 518 
 519   // Extensions directories.
 520   //
 521   // Note that the space for the colon and the trailing null are provided
 522   // by the nulls included by the sizeof operator (so actually one byte more
 523   // than necessary is allocated).
 524   sprintf(buf, "%s" SYS_EXTENSIONS_DIR ":%s" EXTENSIONS_DIR ":" SYS_EXTENSIONS_DIRS,
 525           user_home_dir, Arguments::get_java_home());
 526   Arguments::set_ext_dirs(buf);
 527 
 528   // Endorsed standards default directory.
 529   sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
 530   Arguments::set_endorsed_dirs(buf);
 531 
 532   FREE_C_HEAP_ARRAY(char, buf, mtInternal);
 533 
 534 #undef SYS_EXTENSIONS_DIR
 535 #undef SYS_EXTENSIONS_DIRS
 536 
 537 #endif // __APPLE__
 538 
 539 #undef SYS_EXT_DIR
 540 #undef EXTENSIONS_DIR
 541 #undef ENDORSED_DIR
 542 }
 543 
 544 ////////////////////////////////////////////////////////////////////////////////
 545 // breakpoint support
 546 
 547 void os::breakpoint() {
 548   BREAKPOINT;
 549 }
 550 
 551 extern "C" void breakpoint() {
 552   // use debugger to set breakpoint here
 553 }
 554 
 555 ////////////////////////////////////////////////////////////////////////////////
 556 // signal support
 557 
 558 debug_only(static bool signal_sets_initialized = false);
 559 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
 560 
 561 bool os::Bsd::is_sig_ignored(int sig) {
 562       struct sigaction oact;
 563       sigaction(sig, (struct sigaction*)NULL, &oact);
 564       void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*,  oact.sa_sigaction)
 565                                      : CAST_FROM_FN_PTR(void*,  oact.sa_handler);
 566       if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
 567            return true;
 568       else
 569            return false;
 570 }
 571 
 572 void os::Bsd::signal_sets_init() {
 573   // Should also have an assertion stating we are still single-threaded.
 574   assert(!signal_sets_initialized, "Already initialized");
 575   // Fill in signals that are necessarily unblocked for all threads in
 576   // the VM. Currently, we unblock the following signals:
 577   // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
 578   //                         by -Xrs (=ReduceSignalUsage));
 579   // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
 580   // other threads. The "ReduceSignalUsage" boolean tells us not to alter
 581   // the dispositions or masks wrt these signals.
 582   // Programs embedding the VM that want to use the above signals for their
 583   // own purposes must, at this time, use the "-Xrs" option to prevent
 584   // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
 585   // (See bug 4345157, and other related bugs).
 586   // In reality, though, unblocking these signals is really a nop, since
 587   // these signals are not blocked by default.
 588   sigemptyset(&unblocked_sigs);
 589   sigemptyset(&allowdebug_blocked_sigs);
 590   sigaddset(&unblocked_sigs, SIGILL);
 591   sigaddset(&unblocked_sigs, SIGSEGV);
 592   sigaddset(&unblocked_sigs, SIGBUS);
 593   sigaddset(&unblocked_sigs, SIGFPE);
 594   sigaddset(&unblocked_sigs, SR_signum);
 595 
 596   if (!ReduceSignalUsage) {
 597    if (!os::Bsd::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
 598       sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
 599       sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
 600    }
 601    if (!os::Bsd::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
 602       sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
 603       sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
 604    }
 605    if (!os::Bsd::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
 606       sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
 607       sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
 608    }
 609   }
 610   // Fill in signals that are blocked by all but the VM thread.
 611   sigemptyset(&vm_sigs);
 612   if (!ReduceSignalUsage)
 613     sigaddset(&vm_sigs, BREAK_SIGNAL);
 614   debug_only(signal_sets_initialized = true);
 615 
 616 }
 617 
 618 // These are signals that are unblocked while a thread is running Java.
 619 // (For some reason, they get blocked by default.)
 620 sigset_t* os::Bsd::unblocked_signals() {
 621   assert(signal_sets_initialized, "Not initialized");
 622   return &unblocked_sigs;
 623 }
 624 
 625 // These are the signals that are blocked while a (non-VM) thread is
 626 // running Java. Only the VM thread handles these signals.
 627 sigset_t* os::Bsd::vm_signals() {
 628   assert(signal_sets_initialized, "Not initialized");
 629   return &vm_sigs;
 630 }
 631 
 632 // These are signals that are blocked during cond_wait to allow debugger in
 633 sigset_t* os::Bsd::allowdebug_blocked_signals() {
 634   assert(signal_sets_initialized, "Not initialized");
 635   return &allowdebug_blocked_sigs;
 636 }
 637 
 638 void os::Bsd::hotspot_sigmask(Thread* thread) {
 639 
 640   //Save caller's signal mask before setting VM signal mask
 641   sigset_t caller_sigmask;
 642   pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
 643 
 644   OSThread* osthread = thread->osthread();
 645   osthread->set_caller_sigmask(caller_sigmask);
 646 
 647   pthread_sigmask(SIG_UNBLOCK, os::Bsd::unblocked_signals(), NULL);
 648 
 649   if (!ReduceSignalUsage) {
 650     if (thread->is_VM_thread()) {
 651       // Only the VM thread handles BREAK_SIGNAL ...
 652       pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
 653     } else {
 654       // ... all other threads block BREAK_SIGNAL
 655       pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
 656     }
 657   }
 658 }
 659 
 660 
 661 //////////////////////////////////////////////////////////////////////////////
 662 // create new thread
 663 
 664 // check if it's safe to start a new thread
 665 static bool _thread_safety_check(Thread* thread) {
 666   return true;
 667 }
 668 
 669 #ifdef __APPLE__
 670 // library handle for calling objc_registerThreadWithCollector()
 671 // without static linking to the libobjc library
 672 #define OBJC_LIB "/usr/lib/libobjc.dylib"
 673 #define OBJC_GCREGISTER "objc_registerThreadWithCollector"
 674 typedef void (*objc_registerThreadWithCollector_t)();
 675 extern "C" objc_registerThreadWithCollector_t objc_registerThreadWithCollectorFunction;
 676 objc_registerThreadWithCollector_t objc_registerThreadWithCollectorFunction = NULL;
 677 #endif
 678 
 679 #ifdef __APPLE__
 680 static uint64_t locate_unique_thread_id(mach_port_t mach_thread_port) {
 681   // Additional thread_id used to correlate threads in SA
 682   thread_identifier_info_data_t     m_ident_info;
 683   mach_msg_type_number_t            count = THREAD_IDENTIFIER_INFO_COUNT;
 684 
 685   thread_info(mach_thread_port, THREAD_IDENTIFIER_INFO,
 686               (thread_info_t) &m_ident_info, &count);
 687 
 688   return m_ident_info.thread_id;
 689 }
 690 #endif
 691 
 692 // Thread start routine for all newly created threads
 693 static void *java_start(Thread *thread) {
 694   // Try to randomize the cache line index of hot stack frames.
 695   // This helps when threads of the same stack traces evict each other's
 696   // cache lines. The threads can be either from the same JVM instance, or
 697   // from different JVM instances. The benefit is especially true for
 698   // processors with hyperthreading technology.
 699   static int counter = 0;
 700   int pid = os::current_process_id();
 701   alloca(((pid ^ counter++) & 7) * 128);
 702 
 703   ThreadLocalStorage::set_thread(thread);
 704 
 705   OSThread* osthread = thread->osthread();
 706   Monitor* sync = osthread->startThread_lock();
 707 
 708   // non floating stack BsdThreads needs extra check, see above
 709   if (!_thread_safety_check(thread)) {
 710     // notify parent thread
 711     MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
 712     osthread->set_state(ZOMBIE);
 713     sync->notify_all();
 714     return NULL;
 715   }
 716 
 717   osthread->set_thread_id(os::Bsd::gettid());
 718 
 719 #ifdef __APPLE__
 720   uint64_t unique_thread_id = locate_unique_thread_id(osthread->thread_id());
 721   guarantee(unique_thread_id != 0, "unique thread id was not found");
 722   osthread->set_unique_thread_id(unique_thread_id);
 723 #endif
 724   // initialize signal mask for this thread
 725   os::Bsd::hotspot_sigmask(thread);
 726 
 727   // initialize floating point control register
 728   os::Bsd::init_thread_fpu_state();
 729 
 730 #ifdef __APPLE__
 731   // register thread with objc gc
 732   if (objc_registerThreadWithCollectorFunction != NULL) {
 733     objc_registerThreadWithCollectorFunction();
 734   }
 735 #endif
 736 
 737   // handshaking with parent thread
 738   {
 739     MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
 740 
 741     // notify parent thread
 742     osthread->set_state(INITIALIZED);
 743     sync->notify_all();
 744 
 745     // wait until os::start_thread()
 746     while (osthread->get_state() == INITIALIZED) {
 747       sync->wait(Mutex::_no_safepoint_check_flag);
 748     }
 749   }
 750 
 751   // call one more level start routine
 752   thread->run();
 753 
 754   return 0;
 755 }
 756 
 757 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
 758   assert(thread->osthread() == NULL, "caller responsible");
 759 
 760   // Allocate the OSThread object
 761   OSThread* osthread = new OSThread(NULL, NULL);
 762   if (osthread == NULL) {
 763     return false;
 764   }
 765 
 766   // set the correct thread state
 767   osthread->set_thread_type(thr_type);
 768 
 769   // Initial state is ALLOCATED but not INITIALIZED
 770   osthread->set_state(ALLOCATED);
 771 
 772   thread->set_osthread(osthread);
 773 
 774   // init thread attributes
 775   pthread_attr_t attr;
 776   pthread_attr_init(&attr);
 777   pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 778 
 779   // stack size
 780   if (os::Bsd::supports_variable_stack_size()) {
 781     // calculate stack size if it's not specified by caller
 782     if (stack_size == 0) {
 783       stack_size = os::Bsd::default_stack_size(thr_type);
 784 
 785       switch (thr_type) {
 786       case os::java_thread:
 787         // Java threads use ThreadStackSize which default value can be
 788         // changed with the flag -Xss
 789         assert (JavaThread::stack_size_at_create() > 0, "this should be set");
 790         stack_size = JavaThread::stack_size_at_create();
 791         break;
 792       case os::compiler_thread:
 793         if (CompilerThreadStackSize > 0) {
 794           stack_size = (size_t)(CompilerThreadStackSize * K);
 795           break;
 796         } // else fall through:
 797           // use VMThreadStackSize if CompilerThreadStackSize is not defined
 798       case os::vm_thread:
 799       case os::pgc_thread:
 800       case os::cgc_thread:
 801       case os::watcher_thread:
 802         if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
 803         break;
 804       }
 805     }
 806 
 807     stack_size = MAX2(stack_size, os::Bsd::min_stack_allowed);
 808     pthread_attr_setstacksize(&attr, stack_size);
 809   } else {
 810     // let pthread_create() pick the default value.
 811   }
 812 
 813   ThreadState state;
 814 
 815   {
 816     pthread_t tid;
 817     int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
 818 
 819     pthread_attr_destroy(&attr);
 820 
 821     if (ret != 0) {
 822       if (PrintMiscellaneous && (Verbose || WizardMode)) {
 823         perror("pthread_create()");
 824       }
 825       // Need to clean up stuff we've allocated so far
 826       thread->set_osthread(NULL);
 827       delete osthread;
 828       return false;
 829     }
 830 
 831     // Store pthread info into the OSThread
 832     osthread->set_pthread_id(tid);
 833 
 834     // Wait until child thread is either initialized or aborted
 835     {
 836       Monitor* sync_with_child = osthread->startThread_lock();
 837       MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
 838       while ((state = osthread->get_state()) == ALLOCATED) {
 839         sync_with_child->wait(Mutex::_no_safepoint_check_flag);
 840       }
 841     }
 842 
 843   }
 844 
 845   // Aborted due to thread limit being reached
 846   if (state == ZOMBIE) {
 847       thread->set_osthread(NULL);
 848       delete osthread;
 849       return false;
 850   }
 851 
 852   // The thread is returned suspended (in state INITIALIZED),
 853   // and is started higher up in the call chain
 854   assert(state == INITIALIZED, "race condition");
 855   return true;
 856 }
 857 
 858 /////////////////////////////////////////////////////////////////////////////
 859 // attach existing thread
 860 
 861 // bootstrap the main thread
 862 bool os::create_main_thread(JavaThread* thread) {
 863   assert(os::Bsd::_main_thread == pthread_self(), "should be called inside main thread");
 864   return create_attached_thread(thread);
 865 }
 866 
 867 bool os::create_attached_thread(JavaThread* thread) {
 868 #ifdef ASSERT
 869     thread->verify_not_published();
 870 #endif
 871 
 872   // Allocate the OSThread object
 873   OSThread* osthread = new OSThread(NULL, NULL);
 874 
 875   if (osthread == NULL) {
 876     return false;
 877   }
 878 
 879   osthread->set_thread_id(os::Bsd::gettid());
 880 
 881   // Store pthread info into the OSThread
 882 #ifdef __APPLE__
 883   uint64_t unique_thread_id = locate_unique_thread_id(osthread->thread_id());
 884   guarantee(unique_thread_id != 0, "just checking");
 885   osthread->set_unique_thread_id(unique_thread_id);
 886 #endif
 887   osthread->set_pthread_id(::pthread_self());
 888 
 889   // initialize floating point control register
 890   os::Bsd::init_thread_fpu_state();
 891 
 892   // Initial thread state is RUNNABLE
 893   osthread->set_state(RUNNABLE);
 894 
 895   thread->set_osthread(osthread);
 896 
 897   // initialize signal mask for this thread
 898   // and save the caller's signal mask
 899   os::Bsd::hotspot_sigmask(thread);
 900 
 901   return true;
 902 }
 903 
 904 void os::pd_start_thread(Thread* thread) {
 905   OSThread * osthread = thread->osthread();
 906   assert(osthread->get_state() != INITIALIZED, "just checking");
 907   Monitor* sync_with_child = osthread->startThread_lock();
 908   MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
 909   sync_with_child->notify();
 910 }
 911 
 912 // Free Bsd resources related to the OSThread
 913 void os::free_thread(OSThread* osthread) {
 914   assert(osthread != NULL, "osthread not set");
 915 
 916   if (Thread::current()->osthread() == osthread) {
 917     // Restore caller's signal mask
 918     sigset_t sigmask = osthread->caller_sigmask();
 919     pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
 920    }
 921 
 922   delete osthread;
 923 }
 924 
 925 //////////////////////////////////////////////////////////////////////////////
 926 // thread local storage
 927 
 928 // Restore the thread pointer if the destructor is called. This is in case
 929 // someone from JNI code sets up a destructor with pthread_key_create to run
 930 // detachCurrentThread on thread death. Unless we restore the thread pointer we
 931 // will hang or crash. When detachCurrentThread is called the key will be set
 932 // to null and we will not be called again. If detachCurrentThread is never
 933 // called we could loop forever depending on the pthread implementation.
 934 static void restore_thread_pointer(void* p) {
 935   Thread* thread = (Thread*) p;
 936   os::thread_local_storage_at_put(ThreadLocalStorage::thread_index(), thread);
 937 }
 938 
 939 int os::allocate_thread_local_storage() {
 940   pthread_key_t key;
 941   int rslt = pthread_key_create(&key, restore_thread_pointer);
 942   assert(rslt == 0, "cannot allocate thread local storage");
 943   return (int)key;
 944 }
 945 
 946 // Note: This is currently not used by VM, as we don't destroy TLS key
 947 // on VM exit.
 948 void os::free_thread_local_storage(int index) {
 949   int rslt = pthread_key_delete((pthread_key_t)index);
 950   assert(rslt == 0, "invalid index");
 951 }
 952 
 953 void os::thread_local_storage_at_put(int index, void* value) {
 954   int rslt = pthread_setspecific((pthread_key_t)index, value);
 955   assert(rslt == 0, "pthread_setspecific failed");
 956 }
 957 
 958 extern "C" Thread* get_thread() {
 959   return ThreadLocalStorage::thread();
 960 }
 961 
 962 
 963 ////////////////////////////////////////////////////////////////////////////////
 964 // time support
 965 
 966 // Time since start-up in seconds to a fine granularity.
 967 // Used by VMSelfDestructTimer and the MemProfiler.
 968 double os::elapsedTime() {
 969 
 970   return ((double)os::elapsed_counter()) / os::elapsed_frequency();
 971 }
 972 
 973 jlong os::elapsed_counter() {
 974   return javaTimeNanos() - initial_time_count;
 975 }
 976 
 977 jlong os::elapsed_frequency() {
 978   return NANOSECS_PER_SEC; // nanosecond resolution
 979 }
 980 
 981 bool os::supports_vtime() { return true; }
 982 bool os::enable_vtime()   { return false; }
 983 bool os::vtime_enabled()  { return false; }
 984 
 985 double os::elapsedVTime() {
 986   // better than nothing, but not much
 987   return elapsedTime();
 988 }
 989 
 990 jlong os::javaTimeMillis() {
 991   timeval time;
 992   int status = gettimeofday(&time, NULL);
 993   assert(status != -1, "bsd error");
 994   return jlong(time.tv_sec) * 1000  +  jlong(time.tv_usec / 1000);
 995 }
 996 
 997 #ifndef __APPLE__
 998 #ifndef CLOCK_MONOTONIC
 999 #define CLOCK_MONOTONIC (1)
1000 #endif
1001 #endif
1002 
1003 #ifdef __APPLE__
1004 void os::Bsd::clock_init() {
1005   mach_timebase_info(&_timebase_info);
1006 }
1007 #else
1008 void os::Bsd::clock_init() {
1009   struct timespec res;
1010   struct timespec tp;
1011   if (::clock_getres(CLOCK_MONOTONIC, &res) == 0 &&
1012       ::clock_gettime(CLOCK_MONOTONIC, &tp)  == 0) {
1013     // yes, monotonic clock is supported
1014     _clock_gettime = ::clock_gettime;
1015   }
1016 }
1017 #endif
1018 
1019 
1020 #ifdef __APPLE__
1021 
1022 jlong os::javaTimeNanos() {
1023     const uint64_t tm = mach_absolute_time();
1024     const uint64_t now = (tm * Bsd::_timebase_info.numer) / Bsd::_timebase_info.denom;
1025     const uint64_t prev = Bsd::_max_abstime;
1026     if (now <= prev) {
1027       return prev;   // same or retrograde time;
1028     }
1029     const uint64_t obsv = Atomic::cmpxchg(now, (volatile jlong*)&Bsd::_max_abstime, prev);
1030     assert(obsv >= prev, "invariant");   // Monotonicity
1031     // If the CAS succeeded then we're done and return "now".
1032     // If the CAS failed and the observed value "obsv" is >= now then
1033     // we should return "obsv".  If the CAS failed and now > obsv > prv then
1034     // some other thread raced this thread and installed a new value, in which case
1035     // we could either (a) retry the entire operation, (b) retry trying to install now
1036     // or (c) just return obsv.  We use (c).   No loop is required although in some cases
1037     // we might discard a higher "now" value in deference to a slightly lower but freshly
1038     // installed obsv value.   That's entirely benign -- it admits no new orderings compared
1039     // to (a) or (b) -- and greatly reduces coherence traffic.
1040     // We might also condition (c) on the magnitude of the delta between obsv and now.
1041     // Avoiding excessive CAS operations to hot RW locations is critical.
1042     // See https://blogs.oracle.com/dave/entry/cas_and_cache_trivia_invalidate
1043     return (prev == obsv) ? now : obsv;
1044 }
1045 
1046 #else // __APPLE__
1047 
1048 jlong os::javaTimeNanos() {
1049   if (Bsd::supports_monotonic_clock()) {
1050     struct timespec tp;
1051     int status = Bsd::_clock_gettime(CLOCK_MONOTONIC, &tp);
1052     assert(status == 0, "gettime error");
1053     jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1054     return result;
1055   } else {
1056     timeval time;
1057     int status = gettimeofday(&time, NULL);
1058     assert(status != -1, "bsd error");
1059     jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1060     return 1000 * usecs;
1061   }
1062 }
1063 
1064 #endif // __APPLE__
1065 
1066 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1067   if (Bsd::supports_monotonic_clock()) {
1068     info_ptr->max_value = ALL_64_BITS;
1069 
1070     // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1071     info_ptr->may_skip_backward = false;      // not subject to resetting or drifting
1072     info_ptr->may_skip_forward = false;       // not subject to resetting or drifting
1073   } else {
1074     // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1075     info_ptr->max_value = ALL_64_BITS;
1076 
1077     // gettimeofday is a real time clock so it skips
1078     info_ptr->may_skip_backward = true;
1079     info_ptr->may_skip_forward = true;
1080   }
1081 
1082   info_ptr->kind = JVMTI_TIMER_ELAPSED;                // elapsed not CPU time
1083 }
1084 
1085 // Return the real, user, and system times in seconds from an
1086 // arbitrary fixed point in the past.
1087 bool os::getTimesSecs(double* process_real_time,
1088                       double* process_user_time,
1089                       double* process_system_time) {
1090   struct tms ticks;
1091   clock_t real_ticks = times(&ticks);
1092 
1093   if (real_ticks == (clock_t) (-1)) {
1094     return false;
1095   } else {
1096     double ticks_per_second = (double) clock_tics_per_sec;
1097     *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1098     *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1099     *process_real_time = ((double) real_ticks) / ticks_per_second;
1100 
1101     return true;
1102   }
1103 }
1104 
1105 
1106 char * os::local_time_string(char *buf, size_t buflen) {
1107   struct tm t;
1108   time_t long_time;
1109   time(&long_time);
1110   localtime_r(&long_time, &t);
1111   jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1112                t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1113                t.tm_hour, t.tm_min, t.tm_sec);
1114   return buf;
1115 }
1116 
1117 struct tm* os::localtime_pd(const time_t* clock, struct tm*  res) {
1118   return localtime_r(clock, res);
1119 }
1120 
1121 ////////////////////////////////////////////////////////////////////////////////
1122 // runtime exit support
1123 
1124 // Note: os::shutdown() might be called very early during initialization, or
1125 // called from signal handler. Before adding something to os::shutdown(), make
1126 // sure it is async-safe and can handle partially initialized VM.
1127 void os::shutdown() {
1128 
1129   // allow PerfMemory to attempt cleanup of any persistent resources
1130   perfMemory_exit();
1131 
1132   // needs to remove object in file system
1133   AttachListener::abort();
1134 
1135   // flush buffered output, finish log files
1136   ostream_abort();
1137 
1138   // Check for abort hook
1139   abort_hook_t abort_hook = Arguments::abort_hook();
1140   if (abort_hook != NULL) {
1141     abort_hook();
1142   }
1143 
1144 }
1145 
1146 // Note: os::abort() might be called very early during initialization, or
1147 // called from signal handler. Before adding something to os::abort(), make
1148 // sure it is async-safe and can handle partially initialized VM.
1149 void os::abort(bool dump_core) {
1150   os::shutdown();
1151   if (dump_core) {
1152 #ifndef PRODUCT
1153     fdStream out(defaultStream::output_fd());
1154     out.print_raw("Current thread is ");
1155     char buf[16];
1156     jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1157     out.print_raw_cr(buf);
1158     out.print_raw_cr("Dumping core ...");
1159 #endif
1160     ::abort(); // dump core
1161   }
1162 
1163   ::exit(1);
1164 }
1165 
1166 // Die immediately, no exit hook, no abort hook, no cleanup.
1167 void os::die() {
1168   // _exit() on BsdThreads only kills current thread
1169   ::abort();
1170 }
1171 
1172 // This method is a copy of JDK's sysGetLastErrorString
1173 // from src/solaris/hpi/src/system_md.c
1174 
1175 size_t os::lasterror(char *buf, size_t len) {
1176 
1177   if (errno == 0)  return 0;
1178 
1179   const char *s = ::strerror(errno);
1180   size_t n = ::strlen(s);
1181   if (n >= len) {
1182     n = len - 1;
1183   }
1184   ::strncpy(buf, s, n);
1185   buf[n] = '\0';
1186   return n;
1187 }
1188 
1189 // Information of current thread in variety of formats
1190 pid_t os::Bsd::gettid() {
1191   int retval = -1;
1192 
1193 #ifdef __APPLE__ //XNU kernel
1194   // despite the fact mach port is actually not a thread id use it
1195   // instead of syscall(SYS_thread_selfid) as it certainly fits to u4
1196   retval = ::pthread_mach_thread_np(::pthread_self());
1197   guarantee(retval != 0, "just checking");
1198   return retval;
1199 
1200 #else
1201   #ifdef __FreeBSD__
1202   retval = syscall(SYS_thr_self);
1203   #else
1204     #ifdef __OpenBSD__
1205   retval = syscall(SYS_getthrid);
1206     #else
1207       #ifdef __NetBSD__
1208   retval = (pid_t) syscall(SYS__lwp_self);
1209       #endif
1210     #endif
1211   #endif
1212 #endif
1213 
1214   if (retval == -1) {
1215     return getpid();
1216   }
1217 }
1218 
1219 intx os::current_thread_id() {
1220 #ifdef __APPLE__
1221   return (intx)::pthread_mach_thread_np(::pthread_self());
1222 #else
1223   return (intx)::pthread_self();
1224 #endif
1225 }
1226 
1227 int os::current_process_id() {
1228 
1229   // Under the old bsd thread library, bsd gives each thread
1230   // its own process id. Because of this each thread will return
1231   // a different pid if this method were to return the result
1232   // of getpid(2). Bsd provides no api that returns the pid
1233   // of the launcher thread for the vm. This implementation
1234   // returns a unique pid, the pid of the launcher thread
1235   // that starts the vm 'process'.
1236 
1237   // Under the NPTL, getpid() returns the same pid as the
1238   // launcher thread rather than a unique pid per thread.
1239   // Use gettid() if you want the old pre NPTL behaviour.
1240 
1241   // if you are looking for the result of a call to getpid() that
1242   // returns a unique pid for the calling thread, then look at the
1243   // OSThread::thread_id() method in osThread_bsd.hpp file
1244 
1245   return (int)(_initial_pid ? _initial_pid : getpid());
1246 }
1247 
1248 // DLL functions
1249 
1250 #define JNI_LIB_PREFIX "lib"
1251 #ifdef __APPLE__
1252 #define JNI_LIB_SUFFIX ".dylib"
1253 #else
1254 #define JNI_LIB_SUFFIX ".so"
1255 #endif
1256 
1257 const char* os::dll_file_extension() { return JNI_LIB_SUFFIX; }
1258 
1259 // This must be hard coded because it's the system's temporary
1260 // directory not the java application's temp directory, ala java.io.tmpdir.
1261 #ifdef __APPLE__
1262 // macosx has a secure per-user temporary directory
1263 char temp_path_storage[PATH_MAX];
1264 const char* os::get_temp_directory() {
1265   static char *temp_path = NULL;
1266   if (temp_path == NULL) {
1267     int pathSize = confstr(_CS_DARWIN_USER_TEMP_DIR, temp_path_storage, PATH_MAX);
1268     if (pathSize == 0 || pathSize > PATH_MAX) {
1269       strlcpy(temp_path_storage, "/tmp/", sizeof(temp_path_storage));
1270     }
1271     temp_path = temp_path_storage;
1272   }
1273   return temp_path;
1274 }
1275 #else /* __APPLE__ */
1276 const char* os::get_temp_directory() { return "/tmp"; }
1277 #endif /* __APPLE__ */
1278 
1279 static bool file_exists(const char* filename) {
1280   struct stat statbuf;
1281   if (filename == NULL || strlen(filename) == 0) {
1282     return false;
1283   }
1284   return os::stat(filename, &statbuf) == 0;
1285 }
1286 
1287 bool os::dll_build_name(char* buffer, size_t buflen,
1288                         const char* pname, const char* fname) {
1289   bool retval = false;
1290   // Copied from libhpi
1291   const size_t pnamelen = pname ? strlen(pname) : 0;
1292 
1293   // Return error on buffer overflow.
1294   if (pnamelen + strlen(fname) + strlen(JNI_LIB_PREFIX) + strlen(JNI_LIB_SUFFIX) + 2 > buflen) {
1295     return retval;
1296   }
1297 
1298   if (pnamelen == 0) {
1299     snprintf(buffer, buflen, JNI_LIB_PREFIX "%s" JNI_LIB_SUFFIX, fname);
1300     retval = true;
1301   } else if (strchr(pname, *os::path_separator()) != NULL) {
1302     int n;
1303     char** pelements = split_path(pname, &n);
1304     if (pelements == NULL) {
1305       return false;
1306     }
1307     for (int i = 0 ; i < n ; i++) {
1308       // Really shouldn't be NULL, but check can't hurt
1309       if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1310         continue; // skip the empty path values
1311       }
1312       snprintf(buffer, buflen, "%s/" JNI_LIB_PREFIX "%s" JNI_LIB_SUFFIX,
1313           pelements[i], fname);
1314       if (file_exists(buffer)) {
1315         retval = true;
1316         break;
1317       }
1318     }
1319     // release the storage
1320     for (int i = 0 ; i < n ; i++) {
1321       if (pelements[i] != NULL) {
1322         FREE_C_HEAP_ARRAY(char, pelements[i], mtInternal);
1323       }
1324     }
1325     if (pelements != NULL) {
1326       FREE_C_HEAP_ARRAY(char*, pelements, mtInternal);
1327     }
1328   } else {
1329     snprintf(buffer, buflen, "%s/" JNI_LIB_PREFIX "%s" JNI_LIB_SUFFIX, pname, fname);
1330     retval = true;
1331   }
1332   return retval;
1333 }
1334 
1335 // check if addr is inside libjvm.so
1336 bool os::address_is_in_vm(address addr) {
1337   static address libjvm_base_addr;
1338   Dl_info dlinfo;
1339 
1340   if (libjvm_base_addr == NULL) {
1341     if (dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo) != 0) {
1342       libjvm_base_addr = (address)dlinfo.dli_fbase;
1343     }
1344     assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1345   }
1346 
1347   if (dladdr((void *)addr, &dlinfo) != 0) {
1348     if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1349   }
1350 
1351   return false;
1352 }
1353 
1354 
1355 #define MACH_MAXSYMLEN 256
1356 
1357 bool os::dll_address_to_function_name(address addr, char *buf,
1358                                       int buflen, int *offset) {
1359   // buf is not optional, but offset is optional
1360   assert(buf != NULL, "sanity check");
1361 
1362   Dl_info dlinfo;
1363   char localbuf[MACH_MAXSYMLEN];
1364 
1365   if (dladdr((void*)addr, &dlinfo) != 0) {
1366     // see if we have a matching symbol
1367     if (dlinfo.dli_saddr != NULL && dlinfo.dli_sname != NULL) {
1368       if (!Decoder::demangle(dlinfo.dli_sname, buf, buflen)) {
1369         jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1370       }
1371       if (offset != NULL) *offset = addr - (address)dlinfo.dli_saddr;
1372       return true;
1373     }
1374     // no matching symbol so try for just file info
1375     if (dlinfo.dli_fname != NULL && dlinfo.dli_fbase != NULL) {
1376       if (Decoder::decode((address)(addr - (address)dlinfo.dli_fbase),
1377                           buf, buflen, offset, dlinfo.dli_fname)) {
1378          return true;
1379       }
1380     }
1381 
1382     // Handle non-dynamic manually:
1383     if (dlinfo.dli_fbase != NULL &&
1384         Decoder::decode(addr, localbuf, MACH_MAXSYMLEN, offset,
1385                         dlinfo.dli_fbase)) {
1386       if (!Decoder::demangle(localbuf, buf, buflen)) {
1387         jio_snprintf(buf, buflen, "%s", localbuf);
1388       }
1389       return true;
1390     }
1391   }
1392   buf[0] = '\0';
1393   if (offset != NULL) *offset = -1;
1394   return false;
1395 }
1396 
1397 // ported from solaris version
1398 bool os::dll_address_to_library_name(address addr, char* buf,
1399                                      int buflen, int* offset) {
1400   // buf is not optional, but offset is optional
1401   assert(buf != NULL, "sanity check");
1402 
1403   Dl_info dlinfo;
1404 
1405   if (dladdr((void*)addr, &dlinfo) != 0) {
1406     if (dlinfo.dli_fname != NULL) {
1407       jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1408     }
1409     if (dlinfo.dli_fbase != NULL && offset != NULL) {
1410       *offset = addr - (address)dlinfo.dli_fbase;
1411     }
1412     return true;
1413   }
1414 
1415   buf[0] = '\0';
1416   if (offset) *offset = -1;
1417   return false;
1418 }
1419 
1420 // Loads .dll/.so and
1421 // in case of error it checks if .dll/.so was built for the
1422 // same architecture as Hotspot is running on
1423 
1424 #ifdef __APPLE__
1425 void * os::dll_load(const char *filename, char *ebuf, int ebuflen) {
1426   void * result= ::dlopen(filename, RTLD_LAZY);
1427   if (result != NULL) {
1428     // Successful loading
1429     return result;
1430   }
1431 
1432   // Read system error message into ebuf
1433   ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1434   ebuf[ebuflen-1]='\0';
1435 
1436   return NULL;
1437 }
1438 #else
1439 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1440 {
1441   void * result= ::dlopen(filename, RTLD_LAZY);
1442   if (result != NULL) {
1443     // Successful loading
1444     return result;
1445   }
1446 
1447   Elf32_Ehdr elf_head;
1448 
1449   // Read system error message into ebuf
1450   // It may or may not be overwritten below
1451   ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1452   ebuf[ebuflen-1]='\0';
1453   int diag_msg_max_length=ebuflen-strlen(ebuf);
1454   char* diag_msg_buf=ebuf+strlen(ebuf);
1455 
1456   if (diag_msg_max_length==0) {
1457     // No more space in ebuf for additional diagnostics message
1458     return NULL;
1459   }
1460 
1461 
1462   int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1463 
1464   if (file_descriptor < 0) {
1465     // Can't open library, report dlerror() message
1466     return NULL;
1467   }
1468 
1469   bool failed_to_read_elf_head=
1470     (sizeof(elf_head)!=
1471         (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1472 
1473   ::close(file_descriptor);
1474   if (failed_to_read_elf_head) {
1475     // file i/o error - report dlerror() msg
1476     return NULL;
1477   }
1478 
1479   typedef struct {
1480     Elf32_Half  code;         // Actual value as defined in elf.h
1481     Elf32_Half  compat_class; // Compatibility of archs at VM's sense
1482     char        elf_class;    // 32 or 64 bit
1483     char        endianess;    // MSB or LSB
1484     char*       name;         // String representation
1485   } arch_t;
1486 
1487   #ifndef EM_486
1488   #define EM_486          6               /* Intel 80486 */
1489   #endif
1490 
1491   #ifndef EM_MIPS_RS3_LE
1492   #define EM_MIPS_RS3_LE  10              /* MIPS */
1493   #endif
1494 
1495   #ifndef EM_PPC64
1496   #define EM_PPC64        21              /* PowerPC64 */
1497   #endif
1498 
1499   #ifndef EM_S390
1500   #define EM_S390         22              /* IBM System/390 */
1501   #endif
1502 
1503   #ifndef EM_IA_64
1504   #define EM_IA_64        50              /* HP/Intel IA-64 */
1505   #endif
1506 
1507   #ifndef EM_X86_64
1508   #define EM_X86_64       62              /* AMD x86-64 */
1509   #endif
1510 
1511   static const arch_t arch_array[]={
1512     {EM_386,         EM_386,     ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1513     {EM_486,         EM_386,     ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1514     {EM_IA_64,       EM_IA_64,   ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1515     {EM_X86_64,      EM_X86_64,  ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1516     {EM_SPARC,       EM_SPARC,   ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1517     {EM_SPARC32PLUS, EM_SPARC,   ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1518     {EM_SPARCV9,     EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1519     {EM_PPC,         EM_PPC,     ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1520     {EM_PPC64,       EM_PPC64,   ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1521     {EM_ARM,         EM_ARM,     ELFCLASS32,   ELFDATA2LSB, (char*)"ARM"},
1522     {EM_S390,        EM_S390,    ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1523     {EM_ALPHA,       EM_ALPHA,   ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1524     {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1525     {EM_MIPS,        EM_MIPS,    ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1526     {EM_PARISC,      EM_PARISC,  ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1527     {EM_68K,         EM_68K,     ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1528   };
1529 
1530   #if  (defined IA32)
1531     static  Elf32_Half running_arch_code=EM_386;
1532   #elif   (defined AMD64)
1533     static  Elf32_Half running_arch_code=EM_X86_64;
1534   #elif  (defined IA64)
1535     static  Elf32_Half running_arch_code=EM_IA_64;
1536   #elif  (defined __sparc) && (defined _LP64)
1537     static  Elf32_Half running_arch_code=EM_SPARCV9;
1538   #elif  (defined __sparc) && (!defined _LP64)
1539     static  Elf32_Half running_arch_code=EM_SPARC;
1540   #elif  (defined __powerpc64__)
1541     static  Elf32_Half running_arch_code=EM_PPC64;
1542   #elif  (defined __powerpc__)
1543     static  Elf32_Half running_arch_code=EM_PPC;
1544   #elif  (defined ARM)
1545     static  Elf32_Half running_arch_code=EM_ARM;
1546   #elif  (defined S390)
1547     static  Elf32_Half running_arch_code=EM_S390;
1548   #elif  (defined ALPHA)
1549     static  Elf32_Half running_arch_code=EM_ALPHA;
1550   #elif  (defined MIPSEL)
1551     static  Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1552   #elif  (defined PARISC)
1553     static  Elf32_Half running_arch_code=EM_PARISC;
1554   #elif  (defined MIPS)
1555     static  Elf32_Half running_arch_code=EM_MIPS;
1556   #elif  (defined M68K)
1557     static  Elf32_Half running_arch_code=EM_68K;
1558   #else
1559     #error Method os::dll_load requires that one of following is defined:\
1560          IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1561   #endif
1562 
1563   // Identify compatability class for VM's architecture and library's architecture
1564   // Obtain string descriptions for architectures
1565 
1566   arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1567   int running_arch_index=-1;
1568 
1569   for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1570     if (running_arch_code == arch_array[i].code) {
1571       running_arch_index    = i;
1572     }
1573     if (lib_arch.code == arch_array[i].code) {
1574       lib_arch.compat_class = arch_array[i].compat_class;
1575       lib_arch.name         = arch_array[i].name;
1576     }
1577   }
1578 
1579   assert(running_arch_index != -1,
1580     "Didn't find running architecture code (running_arch_code) in arch_array");
1581   if (running_arch_index == -1) {
1582     // Even though running architecture detection failed
1583     // we may still continue with reporting dlerror() message
1584     return NULL;
1585   }
1586 
1587   if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1588     ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1589     return NULL;
1590   }
1591 
1592 #ifndef S390
1593   if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1594     ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1595     return NULL;
1596   }
1597 #endif // !S390
1598 
1599   if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1600     if ( lib_arch.name!=NULL ) {
1601       ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1602         " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1603         lib_arch.name, arch_array[running_arch_index].name);
1604     } else {
1605       ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1606       " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1607         lib_arch.code,
1608         arch_array[running_arch_index].name);
1609     }
1610   }
1611 
1612   return NULL;
1613 }
1614 #endif /* !__APPLE__ */
1615 
1616 void* os::get_default_process_handle() {
1617 #ifdef __APPLE__
1618   // MacOS X needs to use RTLD_FIRST instead of RTLD_LAZY
1619   // to avoid finding unexpected symbols on second (or later)
1620   // loads of a library.
1621   return (void*)::dlopen(NULL, RTLD_FIRST);
1622 #else
1623   return (void*)::dlopen(NULL, RTLD_LAZY);
1624 #endif
1625 }
1626 
1627 // XXX: Do we need a lock around this as per Linux?
1628 void* os::dll_lookup(void* handle, const char* name) {
1629   return dlsym(handle, name);
1630 }
1631 
1632 
1633 static bool _print_ascii_file(const char* filename, outputStream* st) {
1634   int fd = ::open(filename, O_RDONLY);
1635   if (fd == -1) {
1636      return false;
1637   }
1638 
1639   char buf[32];
1640   int bytes;
1641   while ((bytes = ::read(fd, buf, sizeof(buf))) > 0) {
1642     st->print_raw(buf, bytes);
1643   }
1644 
1645   ::close(fd);
1646 
1647   return true;
1648 }
1649 
1650 void os::print_dll_info(outputStream *st) {
1651   st->print_cr("Dynamic libraries:");
1652 #ifdef RTLD_DI_LINKMAP
1653   Dl_info dli;
1654   void *handle;
1655   Link_map *map;
1656   Link_map *p;
1657 
1658   if (dladdr(CAST_FROM_FN_PTR(void *, os::print_dll_info), &dli) == 0 ||
1659       dli.dli_fname == NULL) {
1660     st->print_cr("Error: Cannot print dynamic libraries.");
1661     return;
1662   }
1663   handle = dlopen(dli.dli_fname, RTLD_LAZY);
1664   if (handle == NULL) {
1665     st->print_cr("Error: Cannot print dynamic libraries.");
1666     return;
1667   }
1668   dlinfo(handle, RTLD_DI_LINKMAP, &map);
1669   if (map == NULL) {
1670     st->print_cr("Error: Cannot print dynamic libraries.");
1671     return;
1672   }
1673 
1674   while (map->l_prev != NULL)
1675     map = map->l_prev;
1676 
1677   while (map != NULL) {
1678     st->print_cr(PTR_FORMAT " \t%s", map->l_addr, map->l_name);
1679     map = map->l_next;
1680   }
1681 
1682   dlclose(handle);
1683 #elif defined(__APPLE__)
1684   for (uint32_t i = 1; i < _dyld_image_count(); i++) {
1685     st->print_cr(PTR_FORMAT " \t%s", _dyld_get_image_header(i),
1686         _dyld_get_image_name(i));
1687   }
1688 #else
1689   st->print_cr("Error: Cannot print dynamic libraries.");
1690 #endif
1691 }
1692 
1693 void os::print_os_info_brief(outputStream* st) {
1694   st->print("Bsd");
1695 
1696   os::Posix::print_uname_info(st);
1697 }
1698 
1699 void os::print_os_info(outputStream* st) {
1700   st->print("OS:");
1701   st->print("Bsd");
1702 
1703   os::Posix::print_uname_info(st);
1704 
1705   os::Posix::print_rlimit_info(st);
1706 
1707   os::Posix::print_load_average(st);
1708 }
1709 
1710 void os::pd_print_cpu_info(outputStream* st) {
1711   // Nothing to do for now.
1712 }
1713 
1714 void os::print_memory_info(outputStream* st) {
1715 
1716   st->print("Memory:");
1717   st->print(" %dk page", os::vm_page_size()>>10);
1718 
1719   st->print(", physical " UINT64_FORMAT "k",
1720             os::physical_memory() >> 10);
1721   st->print("(" UINT64_FORMAT "k free)",
1722             os::available_memory() >> 10);
1723   st->cr();
1724 
1725   // meminfo
1726   st->print("\n/proc/meminfo:\n");
1727   _print_ascii_file("/proc/meminfo", st);
1728   st->cr();
1729 }
1730 
1731 void os::print_siginfo(outputStream* st, void* siginfo) {
1732   const siginfo_t* si = (const siginfo_t*)siginfo;
1733 
1734   os::Posix::print_siginfo_brief(st, si);
1735 
1736   if (si && (si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
1737       UseSharedSpaces) {
1738     FileMapInfo* mapinfo = FileMapInfo::current_info();
1739     if (mapinfo->is_in_shared_space(si->si_addr)) {
1740       st->print("\n\nError accessing class data sharing archive."   \
1741                 " Mapped file inaccessible during execution, "      \
1742                 " possible disk/network problem.");
1743     }
1744   }
1745   st->cr();
1746 }
1747 
1748 
1749 static void print_signal_handler(outputStream* st, int sig,
1750                                  char* buf, size_t buflen);
1751 
1752 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
1753   st->print_cr("Signal Handlers:");
1754   print_signal_handler(st, SIGSEGV, buf, buflen);
1755   print_signal_handler(st, SIGBUS , buf, buflen);
1756   print_signal_handler(st, SIGFPE , buf, buflen);
1757   print_signal_handler(st, SIGPIPE, buf, buflen);
1758   print_signal_handler(st, SIGXFSZ, buf, buflen);
1759   print_signal_handler(st, SIGILL , buf, buflen);
1760   print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
1761   print_signal_handler(st, SR_signum, buf, buflen);
1762   print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
1763   print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
1764   print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
1765   print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
1766 }
1767 
1768 static char saved_jvm_path[MAXPATHLEN] = {0};
1769 
1770 // Find the full path to the current module, libjvm
1771 void os::jvm_path(char *buf, jint buflen) {
1772   // Error checking.
1773   if (buflen < MAXPATHLEN) {
1774     assert(false, "must use a large-enough buffer");
1775     buf[0] = '\0';
1776     return;
1777   }
1778   // Lazy resolve the path to current module.
1779   if (saved_jvm_path[0] != 0) {
1780     strcpy(buf, saved_jvm_path);
1781     return;
1782   }
1783 
1784   char dli_fname[MAXPATHLEN];
1785   bool ret = dll_address_to_library_name(
1786                 CAST_FROM_FN_PTR(address, os::jvm_path),
1787                 dli_fname, sizeof(dli_fname), NULL);
1788   assert(ret, "cannot locate libjvm");
1789   char *rp = NULL;
1790   if (ret && dli_fname[0] != '\0') {
1791     rp = realpath(dli_fname, buf);
1792   }
1793   if (rp == NULL)
1794     return;
1795 
1796   if (Arguments::created_by_gamma_launcher()) {
1797     // Support for the gamma launcher.  Typical value for buf is
1798     // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm".  If "/jre/lib/" appears at
1799     // the right place in the string, then assume we are installed in a JDK and
1800     // we're done.  Otherwise, check for a JAVA_HOME environment variable and
1801     // construct a path to the JVM being overridden.
1802 
1803     const char *p = buf + strlen(buf) - 1;
1804     for (int count = 0; p > buf && count < 5; ++count) {
1805       for (--p; p > buf && *p != '/'; --p)
1806         /* empty */ ;
1807     }
1808 
1809     if (strncmp(p, "/jre/lib/", 9) != 0) {
1810       // Look for JAVA_HOME in the environment.
1811       char* java_home_var = ::getenv("JAVA_HOME");
1812       if (java_home_var != NULL && java_home_var[0] != 0) {
1813         char* jrelib_p;
1814         int len;
1815 
1816         // Check the current module name "libjvm"
1817         p = strrchr(buf, '/');
1818         assert(strstr(p, "/libjvm") == p, "invalid library name");
1819 
1820         rp = realpath(java_home_var, buf);
1821         if (rp == NULL)
1822           return;
1823 
1824         // determine if this is a legacy image or modules image
1825         // modules image doesn't have "jre" subdirectory
1826         len = strlen(buf);
1827         assert(len < buflen, "Ran out of buffer space");
1828         jrelib_p = buf + len;
1829 
1830         // Add the appropriate library subdir
1831         snprintf(jrelib_p, buflen-len, "/jre/lib");
1832         if (0 != access(buf, F_OK)) {
1833           snprintf(jrelib_p, buflen-len, "/lib");
1834         }
1835 
1836         // Add the appropriate client or server subdir
1837         len = strlen(buf);
1838         jrelib_p = buf + len;
1839         snprintf(jrelib_p, buflen-len, "/%s", COMPILER_VARIANT);
1840         if (0 != access(buf, F_OK)) {
1841           snprintf(jrelib_p, buflen-len, "");
1842         }
1843 
1844         // If the path exists within JAVA_HOME, add the JVM library name
1845         // to complete the path to JVM being overridden.  Otherwise fallback
1846         // to the path to the current library.
1847         if (0 == access(buf, F_OK)) {
1848           // Use current module name "libjvm"
1849           len = strlen(buf);
1850           snprintf(buf + len, buflen-len, "/libjvm%s", JNI_LIB_SUFFIX);
1851         } else {
1852           // Fall back to path of current library
1853           rp = realpath(dli_fname, buf);
1854           if (rp == NULL)
1855             return;
1856         }
1857       }
1858     }
1859   }
1860 
1861   strncpy(saved_jvm_path, buf, MAXPATHLEN);
1862 }
1863 
1864 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
1865   // no prefix required, not even "_"
1866 }
1867 
1868 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
1869   // no suffix required
1870 }
1871 
1872 ////////////////////////////////////////////////////////////////////////////////
1873 // sun.misc.Signal support
1874 
1875 static volatile jint sigint_count = 0;
1876 
1877 static void
1878 UserHandler(int sig, void *siginfo, void *context) {
1879   // 4511530 - sem_post is serialized and handled by the manager thread. When
1880   // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
1881   // don't want to flood the manager thread with sem_post requests.
1882   if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
1883       return;
1884 
1885   // Ctrl-C is pressed during error reporting, likely because the error
1886   // handler fails to abort. Let VM die immediately.
1887   if (sig == SIGINT && is_error_reported()) {
1888      os::die();
1889   }
1890 
1891   os::signal_notify(sig);
1892 }
1893 
1894 void* os::user_handler() {
1895   return CAST_FROM_FN_PTR(void*, UserHandler);
1896 }
1897 
1898 extern "C" {
1899   typedef void (*sa_handler_t)(int);
1900   typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
1901 }
1902 
1903 void* os::signal(int signal_number, void* handler) {
1904   struct sigaction sigAct, oldSigAct;
1905 
1906   sigfillset(&(sigAct.sa_mask));
1907   sigAct.sa_flags   = SA_RESTART|SA_SIGINFO;
1908   sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
1909 
1910   if (sigaction(signal_number, &sigAct, &oldSigAct)) {
1911     // -1 means registration failed
1912     return (void *)-1;
1913   }
1914 
1915   return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
1916 }
1917 
1918 void os::signal_raise(int signal_number) {
1919   ::raise(signal_number);
1920 }
1921 
1922 /*
1923  * The following code is moved from os.cpp for making this
1924  * code platform specific, which it is by its very nature.
1925  */
1926 
1927 // Will be modified when max signal is changed to be dynamic
1928 int os::sigexitnum_pd() {
1929   return NSIG;
1930 }
1931 
1932 // a counter for each possible signal value
1933 static volatile jint pending_signals[NSIG+1] = { 0 };
1934 
1935 // Bsd(POSIX) specific hand shaking semaphore.
1936 #ifdef __APPLE__
1937 typedef semaphore_t os_semaphore_t;
1938 #define SEM_INIT(sem, value)    semaphore_create(mach_task_self(), &sem, SYNC_POLICY_FIFO, value)
1939 #define SEM_WAIT(sem)           semaphore_wait(sem)
1940 #define SEM_POST(sem)           semaphore_signal(sem)
1941 #define SEM_DESTROY(sem)        semaphore_destroy(mach_task_self(), sem)
1942 #else
1943 typedef sem_t os_semaphore_t;
1944 #define SEM_INIT(sem, value)    sem_init(&sem, 0, value)
1945 #define SEM_WAIT(sem)           sem_wait(&sem)
1946 #define SEM_POST(sem)           sem_post(&sem)
1947 #define SEM_DESTROY(sem)        sem_destroy(&sem)
1948 #endif
1949 
1950 class Semaphore : public StackObj {
1951   public:
1952     Semaphore();
1953     ~Semaphore();
1954     void signal();
1955     void wait();
1956     bool trywait();
1957     bool timedwait(unsigned int sec, int nsec);
1958   private:
1959     jlong currenttime() const;
1960     os_semaphore_t _semaphore;
1961 };
1962 
1963 Semaphore::Semaphore() : _semaphore(0) {
1964   SEM_INIT(_semaphore, 0);
1965 }
1966 
1967 Semaphore::~Semaphore() {
1968   SEM_DESTROY(_semaphore);
1969 }
1970 
1971 void Semaphore::signal() {
1972   SEM_POST(_semaphore);
1973 }
1974 
1975 void Semaphore::wait() {
1976   SEM_WAIT(_semaphore);
1977 }
1978 
1979 jlong Semaphore::currenttime() const {
1980     struct timeval tv;
1981     gettimeofday(&tv, NULL);
1982     return (tv.tv_sec * NANOSECS_PER_SEC) + (tv.tv_usec * 1000);
1983 }
1984 
1985 #ifdef __APPLE__
1986 bool Semaphore::trywait() {
1987   return timedwait(0, 0);
1988 }
1989 
1990 bool Semaphore::timedwait(unsigned int sec, int nsec) {
1991   kern_return_t kr = KERN_ABORTED;
1992   mach_timespec_t waitspec;
1993   waitspec.tv_sec = sec;
1994   waitspec.tv_nsec = nsec;
1995 
1996   jlong starttime = currenttime();
1997 
1998   kr = semaphore_timedwait(_semaphore, waitspec);
1999   while (kr == KERN_ABORTED) {
2000     jlong totalwait = (sec * NANOSECS_PER_SEC) + nsec;
2001 
2002     jlong current = currenttime();
2003     jlong passedtime = current - starttime;
2004 
2005     if (passedtime >= totalwait) {
2006       waitspec.tv_sec = 0;
2007       waitspec.tv_nsec = 0;
2008     } else {
2009       jlong waittime = totalwait - (current - starttime);
2010       waitspec.tv_sec = waittime / NANOSECS_PER_SEC;
2011       waitspec.tv_nsec = waittime % NANOSECS_PER_SEC;
2012     }
2013 
2014     kr = semaphore_timedwait(_semaphore, waitspec);
2015   }
2016 
2017   return kr == KERN_SUCCESS;
2018 }
2019 
2020 #else
2021 
2022 bool Semaphore::trywait() {
2023   return sem_trywait(&_semaphore) == 0;
2024 }
2025 
2026 bool Semaphore::timedwait(unsigned int sec, int nsec) {
2027   struct timespec ts;
2028   unpackTime(&ts, false, (sec * NANOSECS_PER_SEC) + nsec);
2029 
2030   while (1) {
2031     int result = sem_timedwait(&_semaphore, &ts);
2032     if (result == 0) {
2033       return true;
2034     } else if (errno == EINTR) {
2035       continue;
2036     } else if (errno == ETIMEDOUT) {
2037       return false;
2038     } else {
2039       return false;
2040     }
2041   }
2042 }
2043 
2044 #endif // __APPLE__
2045 
2046 static os_semaphore_t sig_sem;
2047 static Semaphore sr_semaphore;
2048 
2049 void os::signal_init_pd() {
2050   // Initialize signal structures
2051   ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2052 
2053   // Initialize signal semaphore
2054   ::SEM_INIT(sig_sem, 0);
2055 }
2056 
2057 void os::signal_notify(int sig) {
2058   Atomic::inc(&pending_signals[sig]);
2059   ::SEM_POST(sig_sem);
2060 }
2061 
2062 static int check_pending_signals(bool wait) {
2063   Atomic::store(0, &sigint_count);
2064   for (;;) {
2065     for (int i = 0; i < NSIG + 1; i++) {
2066       jint n = pending_signals[i];
2067       if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2068         return i;
2069       }
2070     }
2071     if (!wait) {
2072       return -1;
2073     }
2074     JavaThread *thread = JavaThread::current();
2075     ThreadBlockInVM tbivm(thread);
2076 
2077     bool threadIsSuspended;
2078     do {
2079       thread->set_suspend_equivalent();
2080       // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2081       ::SEM_WAIT(sig_sem);
2082 
2083       // were we externally suspended while we were waiting?
2084       threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2085       if (threadIsSuspended) {
2086         //
2087         // The semaphore has been incremented, but while we were waiting
2088         // another thread suspended us. We don't want to continue running
2089         // while suspended because that would surprise the thread that
2090         // suspended us.
2091         //
2092         ::SEM_POST(sig_sem);
2093 
2094         thread->java_suspend_self();
2095       }
2096     } while (threadIsSuspended);
2097   }
2098 }
2099 
2100 int os::signal_lookup() {
2101   return check_pending_signals(false);
2102 }
2103 
2104 int os::signal_wait() {
2105   return check_pending_signals(true);
2106 }
2107 
2108 ////////////////////////////////////////////////////////////////////////////////
2109 // Virtual Memory
2110 
2111 int os::vm_page_size() {
2112   // Seems redundant as all get out
2113   assert(os::Bsd::page_size() != -1, "must call os::init");
2114   return os::Bsd::page_size();
2115 }
2116 
2117 // Solaris allocates memory by pages.
2118 int os::vm_allocation_granularity() {
2119   assert(os::Bsd::page_size() != -1, "must call os::init");
2120   return os::Bsd::page_size();
2121 }
2122 
2123 // Rationale behind this function:
2124 //  current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2125 //  mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2126 //  samples for JITted code. Here we create private executable mapping over the code cache
2127 //  and then we can use standard (well, almost, as mapping can change) way to provide
2128 //  info for the reporting script by storing timestamp and location of symbol
2129 void bsd_wrap_code(char* base, size_t size) {
2130   static volatile jint cnt = 0;
2131 
2132   if (!UseOprofile) {
2133     return;
2134   }
2135 
2136   char buf[PATH_MAX + 1];
2137   int num = Atomic::add(1, &cnt);
2138 
2139   snprintf(buf, PATH_MAX + 1, "%s/hs-vm-%d-%d",
2140            os::get_temp_directory(), os::current_process_id(), num);
2141   unlink(buf);
2142 
2143   int fd = ::open(buf, O_CREAT | O_RDWR, S_IRWXU);
2144 
2145   if (fd != -1) {
2146     off_t rv = ::lseek(fd, size-2, SEEK_SET);
2147     if (rv != (off_t)-1) {
2148       if (::write(fd, "", 1) == 1) {
2149         mmap(base, size,
2150              PROT_READ|PROT_WRITE|PROT_EXEC,
2151              MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2152       }
2153     }
2154     ::close(fd);
2155     unlink(buf);
2156   }
2157 }
2158 
2159 static void warn_fail_commit_memory(char* addr, size_t size, bool exec,
2160                                     int err) {
2161   warning("INFO: os::commit_memory(" PTR_FORMAT ", " SIZE_FORMAT
2162           ", %d) failed; error='%s' (errno=%d)", addr, size, exec,
2163           strerror(err), err);
2164 }
2165 
2166 // NOTE: Bsd kernel does not really reserve the pages for us.
2167 //       All it does is to check if there are enough free pages
2168 //       left at the time of mmap(). This could be a potential
2169 //       problem.
2170 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
2171   int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2172 #ifdef __OpenBSD__
2173   // XXX: Work-around mmap/MAP_FIXED bug temporarily on OpenBSD
2174   if (::mprotect(addr, size, prot) == 0) {
2175     return true;
2176   }
2177 #else
2178   uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2179                                    MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2180   if (res != (uintptr_t) MAP_FAILED) {
2181     return true;
2182   }
2183 #endif
2184 
2185   // Warn about any commit errors we see in non-product builds just
2186   // in case mmap() doesn't work as described on the man page.
2187   NOT_PRODUCT(warn_fail_commit_memory(addr, size, exec, errno);)
2188 
2189   return false;
2190 }
2191 
2192 bool os::pd_commit_memory(char* addr, size_t size, size_t alignment_hint,
2193                        bool exec) {
2194   // alignment_hint is ignored on this OS
2195   return pd_commit_memory(addr, size, exec);
2196 }
2197 
2198 void os::pd_commit_memory_or_exit(char* addr, size_t size, bool exec,
2199                                   const char* mesg) {
2200   assert(mesg != NULL, "mesg must be specified");
2201   if (!pd_commit_memory(addr, size, exec)) {
2202     // add extra info in product mode for vm_exit_out_of_memory():
2203     PRODUCT_ONLY(warn_fail_commit_memory(addr, size, exec, errno);)
2204     vm_exit_out_of_memory(size, OOM_MMAP_ERROR, mesg);
2205   }
2206 }
2207 
2208 void os::pd_commit_memory_or_exit(char* addr, size_t size,
2209                                   size_t alignment_hint, bool exec,
2210                                   const char* mesg) {
2211   // alignment_hint is ignored on this OS
2212   pd_commit_memory_or_exit(addr, size, exec, mesg);
2213 }
2214 
2215 void os::pd_realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
2216 }
2217 
2218 void os::pd_free_memory(char *addr, size_t bytes, size_t alignment_hint) {
2219   ::madvise(addr, bytes, MADV_DONTNEED);
2220 }
2221 
2222 void os::numa_make_global(char *addr, size_t bytes) {
2223 }
2224 
2225 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2226 }
2227 
2228 bool os::numa_topology_changed()   { return false; }
2229 
2230 size_t os::numa_get_groups_num() {
2231   return 1;
2232 }
2233 
2234 int os::numa_get_group_id() {
2235   return 0;
2236 }
2237 
2238 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2239   if (size > 0) {
2240     ids[0] = 0;
2241     return 1;
2242   }
2243   return 0;
2244 }
2245 
2246 bool os::get_page_info(char *start, page_info* info) {
2247   return false;
2248 }
2249 
2250 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2251   return end;
2252 }
2253 
2254 
2255 bool os::pd_uncommit_memory(char* addr, size_t size) {
2256 #ifdef __OpenBSD__
2257   // XXX: Work-around mmap/MAP_FIXED bug temporarily on OpenBSD
2258   return ::mprotect(addr, size, PROT_NONE) == 0;
2259 #else
2260   uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
2261                 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
2262   return res  != (uintptr_t) MAP_FAILED;
2263 #endif
2264 }
2265 
2266 bool os::pd_create_stack_guard_pages(char* addr, size_t size) {
2267   return os::commit_memory(addr, size, !ExecMem);
2268 }
2269 
2270 // If this is a growable mapping, remove the guard pages entirely by
2271 // munmap()ping them.  If not, just call uncommit_memory().
2272 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2273   return os::uncommit_memory(addr, size);
2274 }
2275 
2276 static address _highest_vm_reserved_address = NULL;
2277 
2278 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2279 // at 'requested_addr'. If there are existing memory mappings at the same
2280 // location, however, they will be overwritten. If 'fixed' is false,
2281 // 'requested_addr' is only treated as a hint, the return value may or
2282 // may not start from the requested address. Unlike Bsd mmap(), this
2283 // function returns NULL to indicate failure.
2284 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2285   char * addr;
2286   int flags;
2287 
2288   flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2289   if (fixed) {
2290     assert((uintptr_t)requested_addr % os::Bsd::page_size() == 0, "unaligned address");
2291     flags |= MAP_FIXED;
2292   }
2293 
2294   // Map reserved/uncommitted pages PROT_NONE so we fail early if we
2295   // touch an uncommitted page. Otherwise, the read/write might
2296   // succeed if we have enough swap space to back the physical page.
2297   addr = (char*)::mmap(requested_addr, bytes, PROT_NONE,
2298                        flags, -1, 0);
2299 
2300   if (addr != MAP_FAILED) {
2301     // anon_mmap() should only get called during VM initialization,
2302     // don't need lock (actually we can skip locking even it can be called
2303     // from multiple threads, because _highest_vm_reserved_address is just a
2304     // hint about the upper limit of non-stack memory regions.)
2305     if ((address)addr + bytes > _highest_vm_reserved_address) {
2306       _highest_vm_reserved_address = (address)addr + bytes;
2307     }
2308   }
2309 
2310   return addr == MAP_FAILED ? NULL : addr;
2311 }
2312 
2313 // Don't update _highest_vm_reserved_address, because there might be memory
2314 // regions above addr + size. If so, releasing a memory region only creates
2315 // a hole in the address space, it doesn't help prevent heap-stack collision.
2316 //
2317 static int anon_munmap(char * addr, size_t size) {
2318   return ::munmap(addr, size) == 0;
2319 }
2320 
2321 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
2322                          size_t alignment_hint) {
2323   return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2324 }
2325 
2326 bool os::pd_release_memory(char* addr, size_t size) {
2327   return anon_munmap(addr, size);
2328 }
2329 
2330 static bool bsd_mprotect(char* addr, size_t size, int prot) {
2331   // Bsd wants the mprotect address argument to be page aligned.
2332   char* bottom = (char*)align_size_down((intptr_t)addr, os::Bsd::page_size());
2333 
2334   // According to SUSv3, mprotect() should only be used with mappings
2335   // established by mmap(), and mmap() always maps whole pages. Unaligned
2336   // 'addr' likely indicates problem in the VM (e.g. trying to change
2337   // protection of malloc'ed or statically allocated memory). Check the
2338   // caller if you hit this assert.
2339   assert(addr == bottom, "sanity check");
2340 
2341   size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Bsd::page_size());
2342   return ::mprotect(bottom, size, prot) == 0;
2343 }
2344 
2345 // Set protections specified
2346 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2347                         bool is_committed) {
2348   unsigned int p = 0;
2349   switch (prot) {
2350   case MEM_PROT_NONE: p = PROT_NONE; break;
2351   case MEM_PROT_READ: p = PROT_READ; break;
2352   case MEM_PROT_RW:   p = PROT_READ|PROT_WRITE; break;
2353   case MEM_PROT_RWX:  p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2354   default:
2355     ShouldNotReachHere();
2356   }
2357   // is_committed is unused.
2358   return bsd_mprotect(addr, bytes, p);
2359 }
2360 
2361 bool os::guard_memory(char* addr, size_t size) {
2362   return bsd_mprotect(addr, size, PROT_NONE);
2363 }
2364 
2365 bool os::unguard_memory(char* addr, size_t size) {
2366   return bsd_mprotect(addr, size, PROT_READ|PROT_WRITE);
2367 }
2368 
2369 bool os::Bsd::hugetlbfs_sanity_check(bool warn, size_t page_size) {
2370   return false;
2371 }
2372 
2373 // Large page support
2374 
2375 static size_t _large_page_size = 0;
2376 
2377 void os::large_page_init() {
2378 }
2379 
2380 
2381 char* os::reserve_memory_special(size_t bytes, size_t alignment, char* req_addr, bool exec) {
2382   fatal("This code is not used or maintained.");
2383 
2384   // "exec" is passed in but not used.  Creating the shared image for
2385   // the code cache doesn't have an SHM_X executable permission to check.
2386   assert(UseLargePages && UseSHM, "only for SHM large pages");
2387 
2388   key_t key = IPC_PRIVATE;
2389   char *addr;
2390 
2391   bool warn_on_failure = UseLargePages &&
2392                         (!FLAG_IS_DEFAULT(UseLargePages) ||
2393                          !FLAG_IS_DEFAULT(LargePageSizeInBytes)
2394                         );
2395 
2396   // Create a large shared memory region to attach to based on size.
2397   // Currently, size is the total size of the heap
2398   int shmid = shmget(key, bytes, IPC_CREAT|SHM_R|SHM_W);
2399   if (shmid == -1) {
2400      // Possible reasons for shmget failure:
2401      // 1. shmmax is too small for Java heap.
2402      //    > check shmmax value: cat /proc/sys/kernel/shmmax
2403      //    > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
2404      // 2. not enough large page memory.
2405      //    > check available large pages: cat /proc/meminfo
2406      //    > increase amount of large pages:
2407      //          echo new_value > /proc/sys/vm/nr_hugepages
2408      //      Note 1: different Bsd may use different name for this property,
2409      //            e.g. on Redhat AS-3 it is "hugetlb_pool".
2410      //      Note 2: it's possible there's enough physical memory available but
2411      //            they are so fragmented after a long run that they can't
2412      //            coalesce into large pages. Try to reserve large pages when
2413      //            the system is still "fresh".
2414      if (warn_on_failure) {
2415        warning("Failed to reserve shared memory (errno = %d).", errno);
2416      }
2417      return NULL;
2418   }
2419 
2420   // attach to the region
2421   addr = (char*)shmat(shmid, req_addr, 0);
2422   int err = errno;
2423 
2424   // Remove shmid. If shmat() is successful, the actual shared memory segment
2425   // will be deleted when it's detached by shmdt() or when the process
2426   // terminates. If shmat() is not successful this will remove the shared
2427   // segment immediately.
2428   shmctl(shmid, IPC_RMID, NULL);
2429 
2430   if ((intptr_t)addr == -1) {
2431      if (warn_on_failure) {
2432        warning("Failed to attach shared memory (errno = %d).", err);
2433      }
2434      return NULL;
2435   }
2436 
2437   // The memory is committed
2438   MemTracker::record_virtual_memory_reserve_and_commit((address)addr, bytes, CALLER_PC);
2439 
2440   return addr;
2441 }
2442 
2443 bool os::release_memory_special(char* base, size_t bytes) {
2444   if (MemTracker::tracking_level() > NMT_minimal) {
2445     Tracker tkr = MemTracker::get_virtual_memory_release_tracker();
2446     // detaching the SHM segment will also delete it, see reserve_memory_special()
2447     int rslt = shmdt(base);
2448     if (rslt == 0) {
2449       tkr.record((address)base, bytes);
2450       return true;
2451     } else {
2452       return false;
2453     }
2454   } else {
2455     return shmdt(base) == 0;
2456   }
2457 }
2458 
2459 size_t os::large_page_size() {
2460   return _large_page_size;
2461 }
2462 
2463 // HugeTLBFS allows application to commit large page memory on demand;
2464 // with SysV SHM the entire memory region must be allocated as shared
2465 // memory.
2466 bool os::can_commit_large_page_memory() {
2467   return UseHugeTLBFS;
2468 }
2469 
2470 bool os::can_execute_large_page_memory() {
2471   return UseHugeTLBFS;
2472 }
2473 
2474 // Reserve memory at an arbitrary address, only if that area is
2475 // available (and not reserved for something else).
2476 
2477 char* os::pd_attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2478   const int max_tries = 10;
2479   char* base[max_tries];
2480   size_t size[max_tries];
2481   const size_t gap = 0x000000;
2482 
2483   // Assert only that the size is a multiple of the page size, since
2484   // that's all that mmap requires, and since that's all we really know
2485   // about at this low abstraction level.  If we need higher alignment,
2486   // we can either pass an alignment to this method or verify alignment
2487   // in one of the methods further up the call chain.  See bug 5044738.
2488   assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
2489 
2490   // Repeatedly allocate blocks until the block is allocated at the
2491   // right spot. Give up after max_tries. Note that reserve_memory() will
2492   // automatically update _highest_vm_reserved_address if the call is
2493   // successful. The variable tracks the highest memory address every reserved
2494   // by JVM. It is used to detect heap-stack collision if running with
2495   // fixed-stack BsdThreads. Because here we may attempt to reserve more
2496   // space than needed, it could confuse the collision detecting code. To
2497   // solve the problem, save current _highest_vm_reserved_address and
2498   // calculate the correct value before return.
2499   address old_highest = _highest_vm_reserved_address;
2500 
2501   // Bsd mmap allows caller to pass an address as hint; give it a try first,
2502   // if kernel honors the hint then we can return immediately.
2503   char * addr = anon_mmap(requested_addr, bytes, false);
2504   if (addr == requested_addr) {
2505      return requested_addr;
2506   }
2507 
2508   if (addr != NULL) {
2509      // mmap() is successful but it fails to reserve at the requested address
2510      anon_munmap(addr, bytes);
2511   }
2512 
2513   int i;
2514   for (i = 0; i < max_tries; ++i) {
2515     base[i] = reserve_memory(bytes);
2516 
2517     if (base[i] != NULL) {
2518       // Is this the block we wanted?
2519       if (base[i] == requested_addr) {
2520         size[i] = bytes;
2521         break;
2522       }
2523 
2524       // Does this overlap the block we wanted? Give back the overlapped
2525       // parts and try again.
2526 
2527       size_t top_overlap = requested_addr + (bytes + gap) - base[i];
2528       if (top_overlap >= 0 && top_overlap < bytes) {
2529         unmap_memory(base[i], top_overlap);
2530         base[i] += top_overlap;
2531         size[i] = bytes - top_overlap;
2532       } else {
2533         size_t bottom_overlap = base[i] + bytes - requested_addr;
2534         if (bottom_overlap >= 0 && bottom_overlap < bytes) {
2535           unmap_memory(requested_addr, bottom_overlap);
2536           size[i] = bytes - bottom_overlap;
2537         } else {
2538           size[i] = bytes;
2539         }
2540       }
2541     }
2542   }
2543 
2544   // Give back the unused reserved pieces.
2545 
2546   for (int j = 0; j < i; ++j) {
2547     if (base[j] != NULL) {
2548       unmap_memory(base[j], size[j]);
2549     }
2550   }
2551 
2552   if (i < max_tries) {
2553     _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
2554     return requested_addr;
2555   } else {
2556     _highest_vm_reserved_address = old_highest;
2557     return NULL;
2558   }
2559 }
2560 
2561 size_t os::read(int fd, void *buf, unsigned int nBytes) {
2562   RESTARTABLE_RETURN_INT(::read(fd, buf, nBytes));
2563 }
2564 
2565 // TODO-FIXME: reconcile Solaris' os::sleep with the bsd variation.
2566 // Solaris uses poll(), bsd uses park().
2567 // Poll() is likely a better choice, assuming that Thread.interrupt()
2568 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
2569 // SIGSEGV, see 4355769.
2570 
2571 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
2572   assert(thread == Thread::current(),  "thread consistency check");
2573 
2574   ParkEvent * const slp = thread->_SleepEvent ;
2575   slp->reset() ;
2576   OrderAccess::fence() ;
2577 
2578   if (interruptible) {
2579     jlong prevtime = javaTimeNanos();
2580 
2581     for (;;) {
2582       if (os::is_interrupted(thread, true)) {
2583         return OS_INTRPT;
2584       }
2585 
2586       jlong newtime = javaTimeNanos();
2587 
2588       if (newtime - prevtime < 0) {
2589         // time moving backwards, should only happen if no monotonic clock
2590         // not a guarantee() because JVM should not abort on kernel/glibc bugs
2591         assert(!Bsd::supports_monotonic_clock(), "time moving backwards");
2592       } else {
2593         millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
2594       }
2595 
2596       if(millis <= 0) {
2597         return OS_OK;
2598       }
2599 
2600       prevtime = newtime;
2601 
2602       {
2603         assert(thread->is_Java_thread(), "sanity check");
2604         JavaThread *jt = (JavaThread *) thread;
2605         ThreadBlockInVM tbivm(jt);
2606         OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
2607 
2608         jt->set_suspend_equivalent();
2609         // cleared by handle_special_suspend_equivalent_condition() or
2610         // java_suspend_self() via check_and_wait_while_suspended()
2611 
2612         slp->park(millis);
2613 
2614         // were we externally suspended while we were waiting?
2615         jt->check_and_wait_while_suspended();
2616       }
2617     }
2618   } else {
2619     OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
2620     jlong prevtime = javaTimeNanos();
2621 
2622     for (;;) {
2623       // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
2624       // the 1st iteration ...
2625       jlong newtime = javaTimeNanos();
2626 
2627       if (newtime - prevtime < 0) {
2628         // time moving backwards, should only happen if no monotonic clock
2629         // not a guarantee() because JVM should not abort on kernel/glibc bugs
2630         assert(!Bsd::supports_monotonic_clock(), "time moving backwards");
2631       } else {
2632         millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
2633       }
2634 
2635       if(millis <= 0) break ;
2636 
2637       prevtime = newtime;
2638       slp->park(millis);
2639     }
2640     return OS_OK ;
2641   }
2642 }
2643 
2644 void os::naked_short_sleep(jlong ms) {
2645   struct timespec req;
2646 
2647   assert(ms < 1000, "Un-interruptable sleep, short time use only");
2648   req.tv_sec = 0;
2649   if (ms > 0) {
2650     req.tv_nsec = (ms % 1000) * 1000000;
2651   }
2652   else {
2653     req.tv_nsec = 1;
2654   }
2655 
2656   nanosleep(&req, NULL);
2657 
2658   return;
2659 }
2660 
2661 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
2662 void os::infinite_sleep() {
2663   while (true) {    // sleep forever ...
2664     ::sleep(100);   // ... 100 seconds at a time
2665   }
2666 }
2667 
2668 // Used to convert frequent JVM_Yield() to nops
2669 bool os::dont_yield() {
2670   return DontYieldALot;
2671 }
2672 
2673 void os::yield() {
2674   sched_yield();
2675 }
2676 
2677 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
2678 
2679 void os::yield_all(int attempts) {
2680   // Yields to all threads, including threads with lower priorities
2681   // Threads on Bsd are all with same priority. The Solaris style
2682   // os::yield_all() with nanosleep(1ms) is not necessary.
2683   sched_yield();
2684 }
2685 
2686 // Called from the tight loops to possibly influence time-sharing heuristics
2687 void os::loop_breaker(int attempts) {
2688   os::yield_all(attempts);
2689 }
2690 
2691 ////////////////////////////////////////////////////////////////////////////////
2692 // thread priority support
2693 
2694 // Note: Normal Bsd applications are run with SCHED_OTHER policy. SCHED_OTHER
2695 // only supports dynamic priority, static priority must be zero. For real-time
2696 // applications, Bsd supports SCHED_RR which allows static priority (1-99).
2697 // However, for large multi-threaded applications, SCHED_RR is not only slower
2698 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
2699 // of 5 runs - Sep 2005).
2700 //
2701 // The following code actually changes the niceness of kernel-thread/LWP. It
2702 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
2703 // not the entire user process, and user level threads are 1:1 mapped to kernel
2704 // threads. It has always been the case, but could change in the future. For
2705 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
2706 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
2707 
2708 #if !defined(__APPLE__)
2709 int os::java_to_os_priority[CriticalPriority + 1] = {
2710   19,              // 0 Entry should never be used
2711 
2712    0,              // 1 MinPriority
2713    3,              // 2
2714    6,              // 3
2715 
2716   10,              // 4
2717   15,              // 5 NormPriority
2718   18,              // 6
2719 
2720   21,              // 7
2721   25,              // 8
2722   28,              // 9 NearMaxPriority
2723 
2724   31,              // 10 MaxPriority
2725 
2726   31               // 11 CriticalPriority
2727 };
2728 #else
2729 /* Using Mach high-level priority assignments */
2730 int os::java_to_os_priority[CriticalPriority + 1] = {
2731    0,              // 0 Entry should never be used (MINPRI_USER)
2732 
2733   27,              // 1 MinPriority
2734   28,              // 2
2735   29,              // 3
2736 
2737   30,              // 4
2738   31,              // 5 NormPriority (BASEPRI_DEFAULT)
2739   32,              // 6
2740 
2741   33,              // 7
2742   34,              // 8
2743   35,              // 9 NearMaxPriority
2744 
2745   36,              // 10 MaxPriority
2746 
2747   36               // 11 CriticalPriority
2748 };
2749 #endif
2750 
2751 static int prio_init() {
2752   if (ThreadPriorityPolicy == 1) {
2753     // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
2754     // if effective uid is not root. Perhaps, a more elegant way of doing
2755     // this is to test CAP_SYS_NICE capability, but that will require libcap.so
2756     if (geteuid() != 0) {
2757       if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
2758         warning("-XX:ThreadPriorityPolicy requires root privilege on Bsd");
2759       }
2760       ThreadPriorityPolicy = 0;
2761     }
2762   }
2763   if (UseCriticalJavaThreadPriority) {
2764     os::java_to_os_priority[MaxPriority] = os::java_to_os_priority[CriticalPriority];
2765   }
2766   return 0;
2767 }
2768 
2769 OSReturn os::set_native_priority(Thread* thread, int newpri) {
2770   if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
2771 
2772 #ifdef __OpenBSD__
2773   // OpenBSD pthread_setprio starves low priority threads
2774   return OS_OK;
2775 #elif defined(__FreeBSD__)
2776   int ret = pthread_setprio(thread->osthread()->pthread_id(), newpri);
2777 #elif defined(__APPLE__) || defined(__NetBSD__)
2778   struct sched_param sp;
2779   int policy;
2780   pthread_t self = pthread_self();
2781 
2782   if (pthread_getschedparam(self, &policy, &sp) != 0)
2783     return OS_ERR;
2784 
2785   sp.sched_priority = newpri;
2786   if (pthread_setschedparam(self, policy, &sp) != 0)
2787     return OS_ERR;
2788 
2789   return OS_OK;
2790 #else
2791   int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
2792   return (ret == 0) ? OS_OK : OS_ERR;
2793 #endif
2794 }
2795 
2796 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
2797   if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
2798     *priority_ptr = java_to_os_priority[NormPriority];
2799     return OS_OK;
2800   }
2801 
2802   errno = 0;
2803 #if defined(__OpenBSD__) || defined(__FreeBSD__)
2804   *priority_ptr = pthread_getprio(thread->osthread()->pthread_id());
2805 #elif defined(__APPLE__) || defined(__NetBSD__)
2806   int policy;
2807   struct sched_param sp;
2808 
2809   pthread_getschedparam(pthread_self(), &policy, &sp);
2810   *priority_ptr = sp.sched_priority;
2811 #else
2812   *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
2813 #endif
2814   return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
2815 }
2816 
2817 // Hint to the underlying OS that a task switch would not be good.
2818 // Void return because it's a hint and can fail.
2819 void os::hint_no_preempt() {}
2820 
2821 ////////////////////////////////////////////////////////////////////////////////
2822 // suspend/resume support
2823 
2824 //  the low-level signal-based suspend/resume support is a remnant from the
2825 //  old VM-suspension that used to be for java-suspension, safepoints etc,
2826 //  within hotspot. Now there is a single use-case for this:
2827 //    - calling get_thread_pc() on the VMThread by the flat-profiler task
2828 //      that runs in the watcher thread.
2829 //  The remaining code is greatly simplified from the more general suspension
2830 //  code that used to be used.
2831 //
2832 //  The protocol is quite simple:
2833 //  - suspend:
2834 //      - sends a signal to the target thread
2835 //      - polls the suspend state of the osthread using a yield loop
2836 //      - target thread signal handler (SR_handler) sets suspend state
2837 //        and blocks in sigsuspend until continued
2838 //  - resume:
2839 //      - sets target osthread state to continue
2840 //      - sends signal to end the sigsuspend loop in the SR_handler
2841 //
2842 //  Note that the SR_lock plays no role in this suspend/resume protocol.
2843 //
2844 
2845 static void resume_clear_context(OSThread *osthread) {
2846   osthread->set_ucontext(NULL);
2847   osthread->set_siginfo(NULL);
2848 }
2849 
2850 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
2851   osthread->set_ucontext(context);
2852   osthread->set_siginfo(siginfo);
2853 }
2854 
2855 //
2856 // Handler function invoked when a thread's execution is suspended or
2857 // resumed. We have to be careful that only async-safe functions are
2858 // called here (Note: most pthread functions are not async safe and
2859 // should be avoided.)
2860 //
2861 // Note: sigwait() is a more natural fit than sigsuspend() from an
2862 // interface point of view, but sigwait() prevents the signal hander
2863 // from being run. libpthread would get very confused by not having
2864 // its signal handlers run and prevents sigwait()'s use with the
2865 // mutex granting granting signal.
2866 //
2867 // Currently only ever called on the VMThread or JavaThread
2868 //
2869 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
2870   // Save and restore errno to avoid confusing native code with EINTR
2871   // after sigsuspend.
2872   int old_errno = errno;
2873 
2874   Thread* thread = Thread::current();
2875   OSThread* osthread = thread->osthread();
2876   assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
2877 
2878   os::SuspendResume::State current = osthread->sr.state();
2879   if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
2880     suspend_save_context(osthread, siginfo, context);
2881 
2882     // attempt to switch the state, we assume we had a SUSPEND_REQUEST
2883     os::SuspendResume::State state = osthread->sr.suspended();
2884     if (state == os::SuspendResume::SR_SUSPENDED) {
2885       sigset_t suspend_set;  // signals for sigsuspend()
2886 
2887       // get current set of blocked signals and unblock resume signal
2888       pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
2889       sigdelset(&suspend_set, SR_signum);
2890 
2891       sr_semaphore.signal();
2892       // wait here until we are resumed
2893       while (1) {
2894         sigsuspend(&suspend_set);
2895 
2896         os::SuspendResume::State result = osthread->sr.running();
2897         if (result == os::SuspendResume::SR_RUNNING) {
2898           sr_semaphore.signal();
2899           break;
2900         } else if (result != os::SuspendResume::SR_SUSPENDED) {
2901           ShouldNotReachHere();
2902         }
2903       }
2904 
2905     } else if (state == os::SuspendResume::SR_RUNNING) {
2906       // request was cancelled, continue
2907     } else {
2908       ShouldNotReachHere();
2909     }
2910 
2911     resume_clear_context(osthread);
2912   } else if (current == os::SuspendResume::SR_RUNNING) {
2913     // request was cancelled, continue
2914   } else if (current == os::SuspendResume::SR_WAKEUP_REQUEST) {
2915     // ignore
2916   } else {
2917     // ignore
2918   }
2919 
2920   errno = old_errno;
2921 }
2922 
2923 
2924 static int SR_initialize() {
2925   struct sigaction act;
2926   char *s;
2927   /* Get signal number to use for suspend/resume */
2928   if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
2929     int sig = ::strtol(s, 0, 10);
2930     if (sig > 0 || sig < NSIG) {
2931         SR_signum = sig;
2932     }
2933   }
2934 
2935   assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
2936         "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
2937 
2938   sigemptyset(&SR_sigset);
2939   sigaddset(&SR_sigset, SR_signum);
2940 
2941   /* Set up signal handler for suspend/resume */
2942   act.sa_flags = SA_RESTART|SA_SIGINFO;
2943   act.sa_handler = (void (*)(int)) SR_handler;
2944 
2945   // SR_signum is blocked by default.
2946   // 4528190 - We also need to block pthread restart signal (32 on all
2947   // supported Bsd platforms). Note that BsdThreads need to block
2948   // this signal for all threads to work properly. So we don't have
2949   // to use hard-coded signal number when setting up the mask.
2950   pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
2951 
2952   if (sigaction(SR_signum, &act, 0) == -1) {
2953     return -1;
2954   }
2955 
2956   // Save signal flag
2957   os::Bsd::set_our_sigflags(SR_signum, act.sa_flags);
2958   return 0;
2959 }
2960 
2961 static int sr_notify(OSThread* osthread) {
2962   int status = pthread_kill(osthread->pthread_id(), SR_signum);
2963   assert_status(status == 0, status, "pthread_kill");
2964   return status;
2965 }
2966 
2967 // "Randomly" selected value for how long we want to spin
2968 // before bailing out on suspending a thread, also how often
2969 // we send a signal to a thread we want to resume
2970 static const int RANDOMLY_LARGE_INTEGER = 1000000;
2971 static const int RANDOMLY_LARGE_INTEGER2 = 100;
2972 
2973 // returns true on success and false on error - really an error is fatal
2974 // but this seems the normal response to library errors
2975 static bool do_suspend(OSThread* osthread) {
2976   assert(osthread->sr.is_running(), "thread should be running");
2977   assert(!sr_semaphore.trywait(), "semaphore has invalid state");
2978 
2979   // mark as suspended and send signal
2980   if (osthread->sr.request_suspend() != os::SuspendResume::SR_SUSPEND_REQUEST) {
2981     // failed to switch, state wasn't running?
2982     ShouldNotReachHere();
2983     return false;
2984   }
2985 
2986   if (sr_notify(osthread) != 0) {
2987     ShouldNotReachHere();
2988   }
2989 
2990   // managed to send the signal and switch to SUSPEND_REQUEST, now wait for SUSPENDED
2991   while (true) {
2992     if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
2993       break;
2994     } else {
2995       // timeout
2996       os::SuspendResume::State cancelled = osthread->sr.cancel_suspend();
2997       if (cancelled == os::SuspendResume::SR_RUNNING) {
2998         return false;
2999       } else if (cancelled == os::SuspendResume::SR_SUSPENDED) {
3000         // make sure that we consume the signal on the semaphore as well
3001         sr_semaphore.wait();
3002         break;
3003       } else {
3004         ShouldNotReachHere();
3005         return false;
3006       }
3007     }
3008   }
3009 
3010   guarantee(osthread->sr.is_suspended(), "Must be suspended");
3011   return true;
3012 }
3013 
3014 static void do_resume(OSThread* osthread) {
3015   assert(osthread->sr.is_suspended(), "thread should be suspended");
3016   assert(!sr_semaphore.trywait(), "invalid semaphore state");
3017 
3018   if (osthread->sr.request_wakeup() != os::SuspendResume::SR_WAKEUP_REQUEST) {
3019     // failed to switch to WAKEUP_REQUEST
3020     ShouldNotReachHere();
3021     return;
3022   }
3023 
3024   while (true) {
3025     if (sr_notify(osthread) == 0) {
3026       if (sr_semaphore.timedwait(0, 2 * NANOSECS_PER_MILLISEC)) {
3027         if (osthread->sr.is_running()) {
3028           return;
3029         }
3030       }
3031     } else {
3032       ShouldNotReachHere();
3033     }
3034   }
3035 
3036   guarantee(osthread->sr.is_running(), "Must be running!");
3037 }
3038 
3039 ////////////////////////////////////////////////////////////////////////////////
3040 // interrupt support
3041 
3042 void os::interrupt(Thread* thread) {
3043   assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3044     "possibility of dangling Thread pointer");
3045 
3046   OSThread* osthread = thread->osthread();
3047 
3048   if (!osthread->interrupted()) {
3049     osthread->set_interrupted(true);
3050     // More than one thread can get here with the same value of osthread,
3051     // resulting in multiple notifications.  We do, however, want the store
3052     // to interrupted() to be visible to other threads before we execute unpark().
3053     OrderAccess::fence();
3054     ParkEvent * const slp = thread->_SleepEvent ;
3055     if (slp != NULL) slp->unpark() ;
3056   }
3057 
3058   // For JSR166. Unpark even if interrupt status already was set
3059   if (thread->is_Java_thread())
3060     ((JavaThread*)thread)->parker()->unpark();
3061 
3062   ParkEvent * ev = thread->_ParkEvent ;
3063   if (ev != NULL) ev->unpark() ;
3064 
3065 }
3066 
3067 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3068   assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3069     "possibility of dangling Thread pointer");
3070 
3071   OSThread* osthread = thread->osthread();
3072 
3073   bool interrupted = osthread->interrupted();
3074 
3075   if (interrupted && clear_interrupted) {
3076     osthread->set_interrupted(false);
3077     // consider thread->_SleepEvent->reset() ... optional optimization
3078   }
3079 
3080   return interrupted;
3081 }
3082 
3083 ///////////////////////////////////////////////////////////////////////////////////
3084 // signal handling (except suspend/resume)
3085 
3086 // This routine may be used by user applications as a "hook" to catch signals.
3087 // The user-defined signal handler must pass unrecognized signals to this
3088 // routine, and if it returns true (non-zero), then the signal handler must
3089 // return immediately.  If the flag "abort_if_unrecognized" is true, then this
3090 // routine will never retun false (zero), but instead will execute a VM panic
3091 // routine kill the process.
3092 //
3093 // If this routine returns false, it is OK to call it again.  This allows
3094 // the user-defined signal handler to perform checks either before or after
3095 // the VM performs its own checks.  Naturally, the user code would be making
3096 // a serious error if it tried to handle an exception (such as a null check
3097 // or breakpoint) that the VM was generating for its own correct operation.
3098 //
3099 // This routine may recognize any of the following kinds of signals:
3100 //    SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3101 // It should be consulted by handlers for any of those signals.
3102 //
3103 // The caller of this routine must pass in the three arguments supplied
3104 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3105 // field of the structure passed to sigaction().  This routine assumes that
3106 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3107 //
3108 // Note that the VM will print warnings if it detects conflicting signal
3109 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3110 //
3111 extern "C" JNIEXPORT int
3112 JVM_handle_bsd_signal(int signo, siginfo_t* siginfo,
3113                         void* ucontext, int abort_if_unrecognized);
3114 
3115 void signalHandler(int sig, siginfo_t* info, void* uc) {
3116   assert(info != NULL && uc != NULL, "it must be old kernel");
3117   int orig_errno = errno;  // Preserve errno value over signal handler.
3118   JVM_handle_bsd_signal(sig, info, uc, true);
3119   errno = orig_errno;
3120 }
3121 
3122 
3123 // This boolean allows users to forward their own non-matching signals
3124 // to JVM_handle_bsd_signal, harmlessly.
3125 bool os::Bsd::signal_handlers_are_installed = false;
3126 
3127 // For signal-chaining
3128 struct sigaction os::Bsd::sigact[MAXSIGNUM];
3129 unsigned int os::Bsd::sigs = 0;
3130 bool os::Bsd::libjsig_is_loaded = false;
3131 typedef struct sigaction *(*get_signal_t)(int);
3132 get_signal_t os::Bsd::get_signal_action = NULL;
3133 
3134 struct sigaction* os::Bsd::get_chained_signal_action(int sig) {
3135   struct sigaction *actp = NULL;
3136 
3137   if (libjsig_is_loaded) {
3138     // Retrieve the old signal handler from libjsig
3139     actp = (*get_signal_action)(sig);
3140   }
3141   if (actp == NULL) {
3142     // Retrieve the preinstalled signal handler from jvm
3143     actp = get_preinstalled_handler(sig);
3144   }
3145 
3146   return actp;
3147 }
3148 
3149 static bool call_chained_handler(struct sigaction *actp, int sig,
3150                                  siginfo_t *siginfo, void *context) {
3151   // Call the old signal handler
3152   if (actp->sa_handler == SIG_DFL) {
3153     // It's more reasonable to let jvm treat it as an unexpected exception
3154     // instead of taking the default action.
3155     return false;
3156   } else if (actp->sa_handler != SIG_IGN) {
3157     if ((actp->sa_flags & SA_NODEFER) == 0) {
3158       // automaticlly block the signal
3159       sigaddset(&(actp->sa_mask), sig);
3160     }
3161 
3162     sa_handler_t hand;
3163     sa_sigaction_t sa;
3164     bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3165     // retrieve the chained handler
3166     if (siginfo_flag_set) {
3167       sa = actp->sa_sigaction;
3168     } else {
3169       hand = actp->sa_handler;
3170     }
3171 
3172     if ((actp->sa_flags & SA_RESETHAND) != 0) {
3173       actp->sa_handler = SIG_DFL;
3174     }
3175 
3176     // try to honor the signal mask
3177     sigset_t oset;
3178     pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3179 
3180     // call into the chained handler
3181     if (siginfo_flag_set) {
3182       (*sa)(sig, siginfo, context);
3183     } else {
3184       (*hand)(sig);
3185     }
3186 
3187     // restore the signal mask
3188     pthread_sigmask(SIG_SETMASK, &oset, 0);
3189   }
3190   // Tell jvm's signal handler the signal is taken care of.
3191   return true;
3192 }
3193 
3194 bool os::Bsd::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3195   bool chained = false;
3196   // signal-chaining
3197   if (UseSignalChaining) {
3198     struct sigaction *actp = get_chained_signal_action(sig);
3199     if (actp != NULL) {
3200       chained = call_chained_handler(actp, sig, siginfo, context);
3201     }
3202   }
3203   return chained;
3204 }
3205 
3206 struct sigaction* os::Bsd::get_preinstalled_handler(int sig) {
3207   if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3208     return &sigact[sig];
3209   }
3210   return NULL;
3211 }
3212 
3213 void os::Bsd::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3214   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3215   sigact[sig] = oldAct;
3216   sigs |= (unsigned int)1 << sig;
3217 }
3218 
3219 // for diagnostic
3220 int os::Bsd::sigflags[MAXSIGNUM];
3221 
3222 int os::Bsd::get_our_sigflags(int sig) {
3223   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3224   return sigflags[sig];
3225 }
3226 
3227 void os::Bsd::set_our_sigflags(int sig, int flags) {
3228   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3229   sigflags[sig] = flags;
3230 }
3231 
3232 void os::Bsd::set_signal_handler(int sig, bool set_installed) {
3233   // Check for overwrite.
3234   struct sigaction oldAct;
3235   sigaction(sig, (struct sigaction*)NULL, &oldAct);
3236 
3237   void* oldhand = oldAct.sa_sigaction
3238                 ? CAST_FROM_FN_PTR(void*,  oldAct.sa_sigaction)
3239                 : CAST_FROM_FN_PTR(void*,  oldAct.sa_handler);
3240   if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3241       oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3242       oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3243     if (AllowUserSignalHandlers || !set_installed) {
3244       // Do not overwrite; user takes responsibility to forward to us.
3245       return;
3246     } else if (UseSignalChaining) {
3247       // save the old handler in jvm
3248       save_preinstalled_handler(sig, oldAct);
3249       // libjsig also interposes the sigaction() call below and saves the
3250       // old sigaction on it own.
3251     } else {
3252       fatal(err_msg("Encountered unexpected pre-existing sigaction handler "
3253                     "%#lx for signal %d.", (long)oldhand, sig));
3254     }
3255   }
3256 
3257   struct sigaction sigAct;
3258   sigfillset(&(sigAct.sa_mask));
3259   sigAct.sa_handler = SIG_DFL;
3260   if (!set_installed) {
3261     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3262   } else {
3263     sigAct.sa_sigaction = signalHandler;
3264     sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3265   }
3266 #ifdef __APPLE__
3267   // Needed for main thread as XNU (Mac OS X kernel) will only deliver SIGSEGV
3268   // (which starts as SIGBUS) on main thread with faulting address inside "stack+guard pages"
3269   // if the signal handler declares it will handle it on alternate stack.
3270   // Notice we only declare we will handle it on alt stack, but we are not
3271   // actually going to use real alt stack - this is just a workaround.
3272   // Please see ux_exception.c, method catch_mach_exception_raise for details
3273   // link http://www.opensource.apple.com/source/xnu/xnu-2050.18.24/bsd/uxkern/ux_exception.c
3274   if (sig == SIGSEGV) {
3275     sigAct.sa_flags |= SA_ONSTACK;
3276   }
3277 #endif
3278 
3279   // Save flags, which are set by ours
3280   assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3281   sigflags[sig] = sigAct.sa_flags;
3282 
3283   int ret = sigaction(sig, &sigAct, &oldAct);
3284   assert(ret == 0, "check");
3285 
3286   void* oldhand2  = oldAct.sa_sigaction
3287                   ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3288                   : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3289   assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3290 }
3291 
3292 // install signal handlers for signals that HotSpot needs to
3293 // handle in order to support Java-level exception handling.
3294 
3295 void os::Bsd::install_signal_handlers() {
3296   if (!signal_handlers_are_installed) {
3297     signal_handlers_are_installed = true;
3298 
3299     // signal-chaining
3300     typedef void (*signal_setting_t)();
3301     signal_setting_t begin_signal_setting = NULL;
3302     signal_setting_t end_signal_setting = NULL;
3303     begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3304                              dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3305     if (begin_signal_setting != NULL) {
3306       end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3307                              dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3308       get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3309                             dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3310       libjsig_is_loaded = true;
3311       assert(UseSignalChaining, "should enable signal-chaining");
3312     }
3313     if (libjsig_is_loaded) {
3314       // Tell libjsig jvm is setting signal handlers
3315       (*begin_signal_setting)();
3316     }
3317 
3318     set_signal_handler(SIGSEGV, true);
3319     set_signal_handler(SIGPIPE, true);
3320     set_signal_handler(SIGBUS, true);
3321     set_signal_handler(SIGILL, true);
3322     set_signal_handler(SIGFPE, true);
3323     set_signal_handler(SIGXFSZ, true);
3324 
3325 #if defined(__APPLE__)
3326     // In Mac OS X 10.4, CrashReporter will write a crash log for all 'fatal' signals, including
3327     // signals caught and handled by the JVM. To work around this, we reset the mach task
3328     // signal handler that's placed on our process by CrashReporter. This disables
3329     // CrashReporter-based reporting.
3330     //
3331     // This work-around is not necessary for 10.5+, as CrashReporter no longer intercedes
3332     // on caught fatal signals.
3333     //
3334     // Additionally, gdb installs both standard BSD signal handlers, and mach exception
3335     // handlers. By replacing the existing task exception handler, we disable gdb's mach
3336     // exception handling, while leaving the standard BSD signal handlers functional.
3337     kern_return_t kr;
3338     kr = task_set_exception_ports(mach_task_self(),
3339         EXC_MASK_BAD_ACCESS | EXC_MASK_ARITHMETIC,
3340         MACH_PORT_NULL,
3341         EXCEPTION_STATE_IDENTITY,
3342         MACHINE_THREAD_STATE);
3343 
3344     assert(kr == KERN_SUCCESS, "could not set mach task signal handler");
3345 #endif
3346 
3347     if (libjsig_is_loaded) {
3348       // Tell libjsig jvm finishes setting signal handlers
3349       (*end_signal_setting)();
3350     }
3351 
3352     // We don't activate signal checker if libjsig is in place, we trust ourselves
3353     // and if UserSignalHandler is installed all bets are off
3354     if (CheckJNICalls) {
3355       if (libjsig_is_loaded) {
3356         if (PrintJNIResolving) {
3357           tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3358         }
3359         check_signals = false;
3360       }
3361       if (AllowUserSignalHandlers) {
3362         if (PrintJNIResolving) {
3363           tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3364         }
3365         check_signals = false;
3366       }
3367     }
3368   }
3369 }
3370 
3371 
3372 /////
3373 // glibc on Bsd platform uses non-documented flag
3374 // to indicate, that some special sort of signal
3375 // trampoline is used.
3376 // We will never set this flag, and we should
3377 // ignore this flag in our diagnostic
3378 #ifdef SIGNIFICANT_SIGNAL_MASK
3379 #undef SIGNIFICANT_SIGNAL_MASK
3380 #endif
3381 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3382 
3383 static const char* get_signal_handler_name(address handler,
3384                                            char* buf, int buflen) {
3385   int offset;
3386   bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3387   if (found) {
3388     // skip directory names
3389     const char *p1, *p2;
3390     p1 = buf;
3391     size_t len = strlen(os::file_separator());
3392     while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3393     jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3394   } else {
3395     jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3396   }
3397   return buf;
3398 }
3399 
3400 static void print_signal_handler(outputStream* st, int sig,
3401                                  char* buf, size_t buflen) {
3402   struct sigaction sa;
3403 
3404   sigaction(sig, NULL, &sa);
3405 
3406   // See comment for SIGNIFICANT_SIGNAL_MASK define
3407   sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3408 
3409   st->print("%s: ", os::exception_name(sig, buf, buflen));
3410 
3411   address handler = (sa.sa_flags & SA_SIGINFO)
3412     ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3413     : CAST_FROM_FN_PTR(address, sa.sa_handler);
3414 
3415   if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3416     st->print("SIG_DFL");
3417   } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3418     st->print("SIG_IGN");
3419   } else {
3420     st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3421   }
3422 
3423   st->print(", sa_mask[0]=");
3424   os::Posix::print_signal_set_short(st, &sa.sa_mask);
3425 
3426   address rh = VMError::get_resetted_sighandler(sig);
3427   // May be, handler was resetted by VMError?
3428   if(rh != NULL) {
3429     handler = rh;
3430     sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3431   }
3432 
3433   st->print(", sa_flags=");
3434   os::Posix::print_sa_flags(st, sa.sa_flags);
3435 
3436   // Check: is it our handler?
3437   if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3438      handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3439     // It is our signal handler
3440     // check for flags, reset system-used one!
3441     if((int)sa.sa_flags != os::Bsd::get_our_sigflags(sig)) {
3442       st->print(
3443                 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3444                 os::Bsd::get_our_sigflags(sig));
3445     }
3446   }
3447   st->cr();
3448 }
3449 
3450 
3451 #define DO_SIGNAL_CHECK(sig) \
3452   if (!sigismember(&check_signal_done, sig)) \
3453     os::Bsd::check_signal_handler(sig)
3454 
3455 // This method is a periodic task to check for misbehaving JNI applications
3456 // under CheckJNI, we can add any periodic checks here
3457 
3458 void os::run_periodic_checks() {
3459 
3460   if (check_signals == false) return;
3461 
3462   // SEGV and BUS if overridden could potentially prevent
3463   // generation of hs*.log in the event of a crash, debugging
3464   // such a case can be very challenging, so we absolutely
3465   // check the following for a good measure:
3466   DO_SIGNAL_CHECK(SIGSEGV);
3467   DO_SIGNAL_CHECK(SIGILL);
3468   DO_SIGNAL_CHECK(SIGFPE);
3469   DO_SIGNAL_CHECK(SIGBUS);
3470   DO_SIGNAL_CHECK(SIGPIPE);
3471   DO_SIGNAL_CHECK(SIGXFSZ);
3472 
3473 
3474   // ReduceSignalUsage allows the user to override these handlers
3475   // see comments at the very top and jvm_solaris.h
3476   if (!ReduceSignalUsage) {
3477     DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3478     DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3479     DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3480     DO_SIGNAL_CHECK(BREAK_SIGNAL);
3481   }
3482 
3483   DO_SIGNAL_CHECK(SR_signum);
3484   DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
3485 }
3486 
3487 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3488 
3489 static os_sigaction_t os_sigaction = NULL;
3490 
3491 void os::Bsd::check_signal_handler(int sig) {
3492   char buf[O_BUFLEN];
3493   address jvmHandler = NULL;
3494 
3495 
3496   struct sigaction act;
3497   if (os_sigaction == NULL) {
3498     // only trust the default sigaction, in case it has been interposed
3499     os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
3500     if (os_sigaction == NULL) return;
3501   }
3502 
3503   os_sigaction(sig, (struct sigaction*)NULL, &act);
3504 
3505 
3506   act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3507 
3508   address thisHandler = (act.sa_flags & SA_SIGINFO)
3509     ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3510     : CAST_FROM_FN_PTR(address, act.sa_handler) ;
3511 
3512 
3513   switch(sig) {
3514   case SIGSEGV:
3515   case SIGBUS:
3516   case SIGFPE:
3517   case SIGPIPE:
3518   case SIGILL:
3519   case SIGXFSZ:
3520     jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
3521     break;
3522 
3523   case SHUTDOWN1_SIGNAL:
3524   case SHUTDOWN2_SIGNAL:
3525   case SHUTDOWN3_SIGNAL:
3526   case BREAK_SIGNAL:
3527     jvmHandler = (address)user_handler();
3528     break;
3529 
3530   case INTERRUPT_SIGNAL:
3531     jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
3532     break;
3533 
3534   default:
3535     if (sig == SR_signum) {
3536       jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
3537     } else {
3538       return;
3539     }
3540     break;
3541   }
3542 
3543   if (thisHandler != jvmHandler) {
3544     tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
3545     tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
3546     tty->print_cr("  found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
3547     // No need to check this sig any longer
3548     sigaddset(&check_signal_done, sig);
3549     // Running under non-interactive shell, SHUTDOWN2_SIGNAL will be reassigned SIG_IGN
3550     if (sig == SHUTDOWN2_SIGNAL && !isatty(fileno(stdin))) {
3551       tty->print_cr("Running in non-interactive shell, %s handler is replaced by shell",
3552                     exception_name(sig, buf, O_BUFLEN));
3553     }
3554   } else if(os::Bsd::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Bsd::get_our_sigflags(sig)) {
3555     tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
3556     tty->print("expected:" PTR32_FORMAT, os::Bsd::get_our_sigflags(sig));
3557     tty->print_cr("  found:" PTR32_FORMAT, act.sa_flags);
3558     // No need to check this sig any longer
3559     sigaddset(&check_signal_done, sig);
3560   }
3561 
3562   // Dump all the signal
3563   if (sigismember(&check_signal_done, sig)) {
3564     print_signal_handlers(tty, buf, O_BUFLEN);
3565   }
3566 }
3567 
3568 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
3569 
3570 extern bool signal_name(int signo, char* buf, size_t len);
3571 
3572 const char* os::exception_name(int exception_code, char* buf, size_t size) {
3573   if (0 < exception_code && exception_code <= SIGRTMAX) {
3574     // signal
3575     if (!signal_name(exception_code, buf, size)) {
3576       jio_snprintf(buf, size, "SIG%d", exception_code);
3577     }
3578     return buf;
3579   } else {
3580     return NULL;
3581   }
3582 }
3583 
3584 // this is called _before_ the most of global arguments have been parsed
3585 void os::init(void) {
3586   char dummy;   /* used to get a guess on initial stack address */
3587 //  first_hrtime = gethrtime();
3588 
3589   // With BsdThreads the JavaMain thread pid (primordial thread)
3590   // is different than the pid of the java launcher thread.
3591   // So, on Bsd, the launcher thread pid is passed to the VM
3592   // via the sun.java.launcher.pid property.
3593   // Use this property instead of getpid() if it was correctly passed.
3594   // See bug 6351349.
3595   pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
3596 
3597   _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
3598 
3599   clock_tics_per_sec = CLK_TCK;
3600 
3601   init_random(1234567);
3602 
3603   ThreadCritical::initialize();
3604 
3605   Bsd::set_page_size(getpagesize());
3606   if (Bsd::page_size() == -1) {
3607     fatal(err_msg("os_bsd.cpp: os::init: sysconf failed (%s)",
3608                   strerror(errno)));
3609   }
3610   init_page_sizes((size_t) Bsd::page_size());
3611 
3612   Bsd::initialize_system_info();
3613 
3614   // _main_thread points to the thread that created/loaded the JVM.
3615   Bsd::_main_thread = pthread_self();
3616 
3617   Bsd::clock_init();
3618   initial_time_count = javaTimeNanos();
3619 
3620 #ifdef __APPLE__
3621   // XXXDARWIN
3622   // Work around the unaligned VM callbacks in hotspot's
3623   // sharedRuntime. The callbacks don't use SSE2 instructions, and work on
3624   // Linux, Solaris, and FreeBSD. On Mac OS X, dyld (rightly so) enforces
3625   // alignment when doing symbol lookup. To work around this, we force early
3626   // binding of all symbols now, thus binding when alignment is known-good.
3627   _dyld_bind_fully_image_containing_address((const void *) &os::init);
3628 #endif
3629 }
3630 
3631 // To install functions for atexit system call
3632 extern "C" {
3633   static void perfMemory_exit_helper() {
3634     perfMemory_exit();
3635   }
3636 }
3637 
3638 // this is called _after_ the global arguments have been parsed
3639 jint os::init_2(void)
3640 {
3641   // Allocate a single page and mark it as readable for safepoint polling
3642   address polling_page = (address) ::mmap(NULL, Bsd::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3643   guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
3644 
3645   os::set_polling_page( polling_page );
3646 
3647 #ifndef PRODUCT
3648   if(Verbose && PrintMiscellaneous)
3649     tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
3650 #endif
3651 
3652   if (!UseMembar) {
3653     address mem_serialize_page = (address) ::mmap(NULL, Bsd::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3654     guarantee( mem_serialize_page != MAP_FAILED, "mmap Failed for memory serialize page");
3655     os::set_memory_serialize_page( mem_serialize_page );
3656 
3657 #ifndef PRODUCT
3658     if(Verbose && PrintMiscellaneous)
3659       tty->print("[Memory Serialize  Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
3660 #endif
3661   }
3662 
3663   // initialize suspend/resume support - must do this before signal_sets_init()
3664   if (SR_initialize() != 0) {
3665     perror("SR_initialize failed");
3666     return JNI_ERR;
3667   }
3668 
3669   Bsd::signal_sets_init();
3670   Bsd::install_signal_handlers();
3671 
3672   // Check minimum allowable stack size for thread creation and to initialize
3673   // the java system classes, including StackOverflowError - depends on page
3674   // size.  Add a page for compiler2 recursion in main thread.
3675   // Add in 2*BytesPerWord times page size to account for VM stack during
3676   // class initialization depending on 32 or 64 bit VM.
3677   os::Bsd::min_stack_allowed = MAX2(os::Bsd::min_stack_allowed,
3678             (size_t)(StackYellowPages+StackRedPages+StackShadowPages+
3679                     2*BytesPerWord COMPILER2_PRESENT(+1)) * Bsd::page_size());
3680 
3681   size_t threadStackSizeInBytes = ThreadStackSize * K;
3682   if (threadStackSizeInBytes != 0 &&
3683       threadStackSizeInBytes < os::Bsd::min_stack_allowed) {
3684         tty->print_cr("\nThe stack size specified is too small, "
3685                       "Specify at least %dk",
3686                       os::Bsd::min_stack_allowed/ K);
3687         return JNI_ERR;
3688   }
3689 
3690   // Make the stack size a multiple of the page size so that
3691   // the yellow/red zones can be guarded.
3692   JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
3693         vm_page_size()));
3694 
3695   if (MaxFDLimit) {
3696     // set the number of file descriptors to max. print out error
3697     // if getrlimit/setrlimit fails but continue regardless.
3698     struct rlimit nbr_files;
3699     int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3700     if (status != 0) {
3701       if (PrintMiscellaneous && (Verbose || WizardMode))
3702         perror("os::init_2 getrlimit failed");
3703     } else {
3704       nbr_files.rlim_cur = nbr_files.rlim_max;
3705 
3706 #ifdef __APPLE__
3707       // Darwin returns RLIM_INFINITY for rlim_max, but fails with EINVAL if
3708       // you attempt to use RLIM_INFINITY. As per setrlimit(2), OPEN_MAX must
3709       // be used instead
3710       nbr_files.rlim_cur = MIN(OPEN_MAX, nbr_files.rlim_cur);
3711 #endif
3712 
3713       status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3714       if (status != 0) {
3715         if (PrintMiscellaneous && (Verbose || WizardMode))
3716           perror("os::init_2 setrlimit failed");
3717       }
3718     }
3719   }
3720 
3721   // at-exit methods are called in the reverse order of their registration.
3722   // atexit functions are called on return from main or as a result of a
3723   // call to exit(3C). There can be only 32 of these functions registered
3724   // and atexit() does not set errno.
3725 
3726   if (PerfAllowAtExitRegistration) {
3727     // only register atexit functions if PerfAllowAtExitRegistration is set.
3728     // atexit functions can be delayed until process exit time, which
3729     // can be problematic for embedded VM situations. Embedded VMs should
3730     // call DestroyJavaVM() to assure that VM resources are released.
3731 
3732     // note: perfMemory_exit_helper atexit function may be removed in
3733     // the future if the appropriate cleanup code can be added to the
3734     // VM_Exit VMOperation's doit method.
3735     if (atexit(perfMemory_exit_helper) != 0) {
3736       warning("os::init2 atexit(perfMemory_exit_helper) failed");
3737     }
3738   }
3739 
3740   // initialize thread priority policy
3741   prio_init();
3742 
3743 #ifdef __APPLE__
3744   // dynamically link to objective c gc registration
3745   void *handleLibObjc = dlopen(OBJC_LIB, RTLD_LAZY);
3746   if (handleLibObjc != NULL) {
3747     objc_registerThreadWithCollectorFunction = (objc_registerThreadWithCollector_t) dlsym(handleLibObjc, OBJC_GCREGISTER);
3748   }
3749 #endif
3750 
3751   return JNI_OK;
3752 }
3753 
3754 // Mark the polling page as unreadable
3755 void os::make_polling_page_unreadable(void) {
3756   if( !guard_memory((char*)_polling_page, Bsd::page_size()) )
3757     fatal("Could not disable polling page");
3758 };
3759 
3760 // Mark the polling page as readable
3761 void os::make_polling_page_readable(void) {
3762   if( !bsd_mprotect((char *)_polling_page, Bsd::page_size(), PROT_READ)) {
3763     fatal("Could not enable polling page");
3764   }
3765 };
3766 
3767 int os::active_processor_count() {
3768   // User has overridden the number of active processors
3769   if (ActiveProcessorCount > 0) {
3770     if (PrintActiveCpus) {
3771       tty->print_cr("active_processor_count: "
3772                     "active processor count set by user : %d",
3773                      ActiveProcessorCount);
3774     }
3775     return ActiveProcessorCount;
3776   }
3777 
3778   return _processor_count;
3779 }
3780 
3781 void os::set_native_thread_name(const char *name) {
3782 #if defined(__APPLE__) && MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_5
3783   // This is only supported in Snow Leopard and beyond
3784   if (name != NULL) {
3785     // Add a "Java: " prefix to the name
3786     char buf[MAXTHREADNAMESIZE];
3787     snprintf(buf, sizeof(buf), "Java: %s", name);
3788     pthread_setname_np(buf);
3789   }
3790 #endif
3791 }
3792 
3793 bool os::distribute_processes(uint length, uint* distribution) {
3794   // Not yet implemented.
3795   return false;
3796 }
3797 
3798 bool os::bind_to_processor(uint processor_id) {
3799   // Not yet implemented.
3800   return false;
3801 }
3802 
3803 void os::SuspendedThreadTask::internal_do_task() {
3804   if (do_suspend(_thread->osthread())) {
3805     SuspendedThreadTaskContext context(_thread, _thread->osthread()->ucontext());
3806     do_task(context);
3807     do_resume(_thread->osthread());
3808   }
3809 }
3810 
3811 ///
3812 class PcFetcher : public os::SuspendedThreadTask {
3813 public:
3814   PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
3815   ExtendedPC result();
3816 protected:
3817   void do_task(const os::SuspendedThreadTaskContext& context);
3818 private:
3819   ExtendedPC _epc;
3820 };
3821 
3822 ExtendedPC PcFetcher::result() {
3823   guarantee(is_done(), "task is not done yet.");
3824   return _epc;
3825 }
3826 
3827 void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
3828   Thread* thread = context.thread();
3829   OSThread* osthread = thread->osthread();
3830   if (osthread->ucontext() != NULL) {
3831     _epc = os::Bsd::ucontext_get_pc((ucontext_t *) context.ucontext());
3832   } else {
3833     // NULL context is unexpected, double-check this is the VMThread
3834     guarantee(thread->is_VM_thread(), "can only be called for VMThread");
3835   }
3836 }
3837 
3838 // Suspends the target using the signal mechanism and then grabs the PC before
3839 // resuming the target. Used by the flat-profiler only
3840 ExtendedPC os::get_thread_pc(Thread* thread) {
3841   // Make sure that it is called by the watcher for the VMThread
3842   assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
3843   assert(thread->is_VM_thread(), "Can only be called for VMThread");
3844 
3845   PcFetcher fetcher(thread);
3846   fetcher.run();
3847   return fetcher.result();
3848 }
3849 
3850 int os::Bsd::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
3851 {
3852   return pthread_cond_timedwait(_cond, _mutex, _abstime);
3853 }
3854 
3855 ////////////////////////////////////////////////////////////////////////////////
3856 // debug support
3857 
3858 bool os::find(address addr, outputStream* st) {
3859   Dl_info dlinfo;
3860   memset(&dlinfo, 0, sizeof(dlinfo));
3861   if (dladdr(addr, &dlinfo) != 0) {
3862     st->print(PTR_FORMAT ": ", addr);
3863     if (dlinfo.dli_sname != NULL && dlinfo.dli_saddr != NULL) {
3864       st->print("%s+%#x", dlinfo.dli_sname,
3865                  addr - (intptr_t)dlinfo.dli_saddr);
3866     } else if (dlinfo.dli_fbase != NULL) {
3867       st->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
3868     } else {
3869       st->print("<absolute address>");
3870     }
3871     if (dlinfo.dli_fname != NULL) {
3872       st->print(" in %s", dlinfo.dli_fname);
3873     }
3874     if (dlinfo.dli_fbase != NULL) {
3875       st->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
3876     }
3877     st->cr();
3878 
3879     if (Verbose) {
3880       // decode some bytes around the PC
3881       address begin = clamp_address_in_page(addr-40, addr, os::vm_page_size());
3882       address end   = clamp_address_in_page(addr+40, addr, os::vm_page_size());
3883       address       lowest = (address) dlinfo.dli_sname;
3884       if (!lowest)  lowest = (address) dlinfo.dli_fbase;
3885       if (begin < lowest)  begin = lowest;
3886       Dl_info dlinfo2;
3887       if (dladdr(end, &dlinfo2) != 0 && dlinfo2.dli_saddr != dlinfo.dli_saddr
3888           && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
3889         end = (address) dlinfo2.dli_saddr;
3890       Disassembler::decode(begin, end, st);
3891     }
3892     return true;
3893   }
3894   return false;
3895 }
3896 
3897 ////////////////////////////////////////////////////////////////////////////////
3898 // misc
3899 
3900 // This does not do anything on Bsd. This is basically a hook for being
3901 // able to use structured exception handling (thread-local exception filters)
3902 // on, e.g., Win32.
3903 void
3904 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
3905                          JavaCallArguments* args, Thread* thread) {
3906   f(value, method, args, thread);
3907 }
3908 
3909 void os::print_statistics() {
3910 }
3911 
3912 int os::message_box(const char* title, const char* message) {
3913   int i;
3914   fdStream err(defaultStream::error_fd());
3915   for (i = 0; i < 78; i++) err.print_raw("=");
3916   err.cr();
3917   err.print_raw_cr(title);
3918   for (i = 0; i < 78; i++) err.print_raw("-");
3919   err.cr();
3920   err.print_raw_cr(message);
3921   for (i = 0; i < 78; i++) err.print_raw("=");
3922   err.cr();
3923 
3924   char buf[16];
3925   // Prevent process from exiting upon "read error" without consuming all CPU
3926   while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
3927 
3928   return buf[0] == 'y' || buf[0] == 'Y';
3929 }
3930 
3931 int os::stat(const char *path, struct stat *sbuf) {
3932   char pathbuf[MAX_PATH];
3933   if (strlen(path) > MAX_PATH - 1) {
3934     errno = ENAMETOOLONG;
3935     return -1;
3936   }
3937   os::native_path(strcpy(pathbuf, path));
3938   return ::stat(pathbuf, sbuf);
3939 }
3940 
3941 bool os::check_heap(bool force) {
3942   return true;
3943 }
3944 
3945 ATTRIBUTE_PRINTF(3, 0)
3946 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
3947   return ::vsnprintf(buf, count, format, args);
3948 }
3949 
3950 // Is a (classpath) directory empty?
3951 bool os::dir_is_empty(const char* path) {
3952   DIR *dir = NULL;
3953   struct dirent *ptr;
3954 
3955   dir = opendir(path);
3956   if (dir == NULL) return true;
3957 
3958   /* Scan the directory */
3959   bool result = true;
3960   while (result && (ptr = readdir(dir)) != NULL) {
3961     if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
3962       result = false;
3963     }
3964   }
3965   closedir(dir);
3966   return result;
3967 }
3968 
3969 // This code originates from JDK's sysOpen and open64_w
3970 // from src/solaris/hpi/src/system_md.c
3971 
3972 #ifndef O_DELETE
3973 #define O_DELETE 0x10000
3974 #endif
3975 
3976 // Open a file. Unlink the file immediately after open returns
3977 // if the specified oflag has the O_DELETE flag set.
3978 // O_DELETE is used only in j2se/src/share/native/java/util/zip/ZipFile.c
3979 
3980 int os::open(const char *path, int oflag, int mode) {
3981 
3982   if (strlen(path) > MAX_PATH - 1) {
3983     errno = ENAMETOOLONG;
3984     return -1;
3985   }
3986   int fd;
3987   int o_delete = (oflag & O_DELETE);
3988   oflag = oflag & ~O_DELETE;
3989 
3990   fd = ::open(path, oflag, mode);
3991   if (fd == -1) return -1;
3992 
3993   //If the open succeeded, the file might still be a directory
3994   {
3995     struct stat buf;
3996     int ret = ::fstat(fd, &buf);
3997     int st_mode = buf.st_mode;
3998 
3999     if (ret != -1) {
4000       if ((st_mode & S_IFMT) == S_IFDIR) {
4001         errno = EISDIR;
4002         ::close(fd);
4003         return -1;
4004       }
4005     } else {
4006       ::close(fd);
4007       return -1;
4008     }
4009   }
4010 
4011     /*
4012      * All file descriptors that are opened in the JVM and not
4013      * specifically destined for a subprocess should have the
4014      * close-on-exec flag set.  If we don't set it, then careless 3rd
4015      * party native code might fork and exec without closing all
4016      * appropriate file descriptors (e.g. as we do in closeDescriptors in
4017      * UNIXProcess.c), and this in turn might:
4018      *
4019      * - cause end-of-file to fail to be detected on some file
4020      *   descriptors, resulting in mysterious hangs, or
4021      *
4022      * - might cause an fopen in the subprocess to fail on a system
4023      *   suffering from bug 1085341.
4024      *
4025      * (Yes, the default setting of the close-on-exec flag is a Unix
4026      * design flaw)
4027      *
4028      * See:
4029      * 1085341: 32-bit stdio routines should support file descriptors >255
4030      * 4843136: (process) pipe file descriptor from Runtime.exec not being closed
4031      * 6339493: (process) Runtime.exec does not close all file descriptors on Solaris 9
4032      */
4033 #ifdef FD_CLOEXEC
4034     {
4035         int flags = ::fcntl(fd, F_GETFD);
4036         if (flags != -1)
4037             ::fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
4038     }
4039 #endif
4040 
4041   if (o_delete != 0) {
4042     ::unlink(path);
4043   }
4044   return fd;
4045 }
4046 
4047 
4048 // create binary file, rewriting existing file if required
4049 int os::create_binary_file(const char* path, bool rewrite_existing) {
4050   int oflags = O_WRONLY | O_CREAT;
4051   if (!rewrite_existing) {
4052     oflags |= O_EXCL;
4053   }
4054   return ::open(path, oflags, S_IREAD | S_IWRITE);
4055 }
4056 
4057 // return current position of file pointer
4058 jlong os::current_file_offset(int fd) {
4059   return (jlong)::lseek(fd, (off_t)0, SEEK_CUR);
4060 }
4061 
4062 // move file pointer to the specified offset
4063 jlong os::seek_to_file_offset(int fd, jlong offset) {
4064   return (jlong)::lseek(fd, (off_t)offset, SEEK_SET);
4065 }
4066 
4067 // This code originates from JDK's sysAvailable
4068 // from src/solaris/hpi/src/native_threads/src/sys_api_td.c
4069 
4070 int os::available(int fd, jlong *bytes) {
4071   jlong cur, end;
4072   int mode;
4073   struct stat buf;
4074 
4075   if (::fstat(fd, &buf) >= 0) {
4076     mode = buf.st_mode;
4077     if (S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) {
4078       /*
4079       * XXX: is the following call interruptible? If so, this might
4080       * need to go through the INTERRUPT_IO() wrapper as for other
4081       * blocking, interruptible calls in this file.
4082       */
4083       int n;
4084       if (::ioctl(fd, FIONREAD, &n) >= 0) {
4085         *bytes = n;
4086         return 1;
4087       }
4088     }
4089   }
4090   if ((cur = ::lseek(fd, 0L, SEEK_CUR)) == -1) {
4091     return 0;
4092   } else if ((end = ::lseek(fd, 0L, SEEK_END)) == -1) {
4093     return 0;
4094   } else if (::lseek(fd, cur, SEEK_SET) == -1) {
4095     return 0;
4096   }
4097   *bytes = end - cur;
4098   return 1;
4099 }
4100 
4101 int os::socket_available(int fd, jint *pbytes) {
4102    if (fd < 0)
4103      return OS_OK;
4104 
4105    int ret;
4106 
4107    RESTARTABLE(::ioctl(fd, FIONREAD, pbytes), ret);
4108 
4109    //%% note ioctl can return 0 when successful, JVM_SocketAvailable
4110    // is expected to return 0 on failure and 1 on success to the jdk.
4111 
4112    return (ret == OS_ERR) ? 0 : 1;
4113 }
4114 
4115 // Map a block of memory.
4116 char* os::pd_map_memory(int fd, const char* file_name, size_t file_offset,
4117                      char *addr, size_t bytes, bool read_only,
4118                      bool allow_exec) {
4119   int prot;
4120   int flags;
4121 
4122   if (read_only) {
4123     prot = PROT_READ;
4124     flags = MAP_SHARED;
4125   } else {
4126     prot = PROT_READ | PROT_WRITE;
4127     flags = MAP_PRIVATE;
4128   }
4129 
4130   if (allow_exec) {
4131     prot |= PROT_EXEC;
4132   }
4133 
4134   if (addr != NULL) {
4135     flags |= MAP_FIXED;
4136   }
4137 
4138   char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4139                                      fd, file_offset);
4140   if (mapped_address == MAP_FAILED) {
4141     return NULL;
4142   }
4143   return mapped_address;
4144 }
4145 
4146 
4147 // Remap a block of memory.
4148 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset,
4149                        char *addr, size_t bytes, bool read_only,
4150                        bool allow_exec) {
4151   // same as map_memory() on this OS
4152   return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4153                         allow_exec);
4154 }
4155 
4156 
4157 // Unmap a block of memory.
4158 bool os::pd_unmap_memory(char* addr, size_t bytes) {
4159   return munmap(addr, bytes) == 0;
4160 }
4161 
4162 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4163 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4164 // of a thread.
4165 //
4166 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4167 // the fast estimate available on the platform.
4168 
4169 jlong os::current_thread_cpu_time() {
4170 #ifdef __APPLE__
4171   return os::thread_cpu_time(Thread::current(), true /* user + sys */);
4172 #else
4173   Unimplemented();
4174   return 0;
4175 #endif
4176 }
4177 
4178 jlong os::thread_cpu_time(Thread* thread) {
4179 #ifdef __APPLE__
4180   return os::thread_cpu_time(thread, true /* user + sys */);
4181 #else
4182   Unimplemented();
4183   return 0;
4184 #endif
4185 }
4186 
4187 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4188 #ifdef __APPLE__
4189   return os::thread_cpu_time(Thread::current(), user_sys_cpu_time);
4190 #else
4191   Unimplemented();
4192   return 0;
4193 #endif
4194 }
4195 
4196 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4197 #ifdef __APPLE__
4198   struct thread_basic_info tinfo;
4199   mach_msg_type_number_t tcount = THREAD_INFO_MAX;
4200   kern_return_t kr;
4201   thread_t mach_thread;
4202 
4203   mach_thread = thread->osthread()->thread_id();
4204   kr = thread_info(mach_thread, THREAD_BASIC_INFO, (thread_info_t)&tinfo, &tcount);
4205   if (kr != KERN_SUCCESS)
4206     return -1;
4207 
4208   if (user_sys_cpu_time) {
4209     jlong nanos;
4210     nanos = ((jlong) tinfo.system_time.seconds + tinfo.user_time.seconds) * (jlong)1000000000;
4211     nanos += ((jlong) tinfo.system_time.microseconds + (jlong) tinfo.user_time.microseconds) * (jlong)1000;
4212     return nanos;
4213   } else {
4214     return ((jlong)tinfo.user_time.seconds * 1000000000) + ((jlong)tinfo.user_time.microseconds * (jlong)1000);
4215   }
4216 #else
4217   Unimplemented();
4218   return 0;
4219 #endif
4220 }
4221 
4222 
4223 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4224   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4225   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4226   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4227   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4228 }
4229 
4230 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4231   info_ptr->max_value = ALL_64_BITS;       // will not wrap in less than 64 bits
4232   info_ptr->may_skip_backward = false;     // elapsed time not wall time
4233   info_ptr->may_skip_forward = false;      // elapsed time not wall time
4234   info_ptr->kind = JVMTI_TIMER_TOTAL_CPU;  // user+system time is returned
4235 }
4236 
4237 bool os::is_thread_cpu_time_supported() {
4238 #ifdef __APPLE__
4239   return true;
4240 #else
4241   return false;
4242 #endif
4243 }
4244 
4245 // System loadavg support.  Returns -1 if load average cannot be obtained.
4246 // Bsd doesn't yet have a (official) notion of processor sets,
4247 // so just return the system wide load average.
4248 int os::loadavg(double loadavg[], int nelem) {
4249   return ::getloadavg(loadavg, nelem);
4250 }
4251 
4252 void os::pause() {
4253   char filename[MAX_PATH];
4254   if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4255     jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4256   } else {
4257     jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4258   }
4259 
4260   int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4261   if (fd != -1) {
4262     struct stat buf;
4263     ::close(fd);
4264     while (::stat(filename, &buf) == 0) {
4265       (void)::poll(NULL, 0, 100);
4266     }
4267   } else {
4268     jio_fprintf(stderr,
4269       "Could not open pause file '%s', continuing immediately.\n", filename);
4270   }
4271 }
4272 
4273 
4274 // Refer to the comments in os_solaris.cpp park-unpark.
4275 //
4276 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4277 // hang indefinitely.  For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4278 // For specifics regarding the bug see GLIBC BUGID 261237 :
4279 //    http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4280 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4281 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4282 // is used.  (The simple C test-case provided in the GLIBC bug report manifests the
4283 // hang).  The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4284 // and monitorenter when we're using 1-0 locking.  All those operations may result in
4285 // calls to pthread_cond_timedwait().  Using LD_ASSUME_KERNEL to use an older version
4286 // of libpthread avoids the problem, but isn't practical.
4287 //
4288 // Possible remedies:
4289 //
4290 // 1.   Establish a minimum relative wait time.  50 to 100 msecs seems to work.
4291 //      This is palliative and probabilistic, however.  If the thread is preempted
4292 //      between the call to compute_abstime() and pthread_cond_timedwait(), more
4293 //      than the minimum period may have passed, and the abstime may be stale (in the
4294 //      past) resultin in a hang.   Using this technique reduces the odds of a hang
4295 //      but the JVM is still vulnerable, particularly on heavily loaded systems.
4296 //
4297 // 2.   Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4298 //      of the usual flag-condvar-mutex idiom.  The write side of the pipe is set
4299 //      NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4300 //      reduces to poll()+read().  This works well, but consumes 2 FDs per extant
4301 //      thread.
4302 //
4303 // 3.   Embargo pthread_cond_timedwait() and implement a native "chron" thread
4304 //      that manages timeouts.  We'd emulate pthread_cond_timedwait() by enqueuing
4305 //      a timeout request to the chron thread and then blocking via pthread_cond_wait().
4306 //      This also works well.  In fact it avoids kernel-level scalability impediments
4307 //      on certain platforms that don't handle lots of active pthread_cond_timedwait()
4308 //      timers in a graceful fashion.
4309 //
4310 // 4.   When the abstime value is in the past it appears that control returns
4311 //      correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4312 //      Subsequent timedwait/wait calls may hang indefinitely.  Given that, we
4313 //      can avoid the problem by reinitializing the condvar -- by cond_destroy()
4314 //      followed by cond_init() -- after all calls to pthread_cond_timedwait().
4315 //      It may be possible to avoid reinitialization by checking the return
4316 //      value from pthread_cond_timedwait().  In addition to reinitializing the
4317 //      condvar we must establish the invariant that cond_signal() is only called
4318 //      within critical sections protected by the adjunct mutex.  This prevents
4319 //      cond_signal() from "seeing" a condvar that's in the midst of being
4320 //      reinitialized or that is corrupt.  Sadly, this invariant obviates the
4321 //      desirable signal-after-unlock optimization that avoids futile context switching.
4322 //
4323 //      I'm also concerned that some versions of NTPL might allocate an auxilliary
4324 //      structure when a condvar is used or initialized.  cond_destroy()  would
4325 //      release the helper structure.  Our reinitialize-after-timedwait fix
4326 //      put excessive stress on malloc/free and locks protecting the c-heap.
4327 //
4328 // We currently use (4).  See the WorkAroundNTPLTimedWaitHang flag.
4329 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4330 // and only enabling the work-around for vulnerable environments.
4331 
4332 // utility to compute the abstime argument to timedwait:
4333 // millis is the relative timeout time
4334 // abstime will be the absolute timeout time
4335 // TODO: replace compute_abstime() with unpackTime()
4336 
4337 static struct timespec* compute_abstime(struct timespec* abstime, jlong millis) {
4338   if (millis < 0)  millis = 0;
4339   struct timeval now;
4340   int status = gettimeofday(&now, NULL);
4341   assert(status == 0, "gettimeofday");
4342   jlong seconds = millis / 1000;
4343   millis %= 1000;
4344   if (seconds > 50000000) { // see man cond_timedwait(3T)
4345     seconds = 50000000;
4346   }
4347   abstime->tv_sec = now.tv_sec  + seconds;
4348   long       usec = now.tv_usec + millis * 1000;
4349   if (usec >= 1000000) {
4350     abstime->tv_sec += 1;
4351     usec -= 1000000;
4352   }
4353   abstime->tv_nsec = usec * 1000;
4354   return abstime;
4355 }
4356 
4357 
4358 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
4359 // Conceptually TryPark() should be equivalent to park(0).
4360 
4361 int os::PlatformEvent::TryPark() {
4362   for (;;) {
4363     const int v = _Event ;
4364     guarantee ((v == 0) || (v == 1), "invariant") ;
4365     if (Atomic::cmpxchg (0, &_Event, v) == v) return v  ;
4366   }
4367 }
4368 
4369 void os::PlatformEvent::park() {       // AKA "down()"
4370   // Invariant: Only the thread associated with the Event/PlatformEvent
4371   // may call park().
4372   // TODO: assert that _Assoc != NULL or _Assoc == Self
4373   int v ;
4374   for (;;) {
4375       v = _Event ;
4376       if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
4377   }
4378   guarantee (v >= 0, "invariant") ;
4379   if (v == 0) {
4380      // Do this the hard way by blocking ...
4381      int status = pthread_mutex_lock(_mutex);
4382      assert_status(status == 0, status, "mutex_lock");
4383      guarantee (_nParked == 0, "invariant") ;
4384      ++ _nParked ;
4385      while (_Event < 0) {
4386         status = pthread_cond_wait(_cond, _mutex);
4387         // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
4388         // Treat this the same as if the wait was interrupted
4389         if (status == ETIMEDOUT) { status = EINTR; }
4390         assert_status(status == 0 || status == EINTR, status, "cond_wait");
4391      }
4392      -- _nParked ;
4393 
4394     _Event = 0 ;
4395      status = pthread_mutex_unlock(_mutex);
4396      assert_status(status == 0, status, "mutex_unlock");
4397     // Paranoia to ensure our locked and lock-free paths interact
4398     // correctly with each other.
4399     OrderAccess::fence();
4400   }
4401   guarantee (_Event >= 0, "invariant") ;
4402 }
4403 
4404 int os::PlatformEvent::park(jlong millis) {
4405   guarantee (_nParked == 0, "invariant") ;
4406 
4407   int v ;
4408   for (;;) {
4409       v = _Event ;
4410       if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
4411   }
4412   guarantee (v >= 0, "invariant") ;
4413   if (v != 0) return OS_OK ;
4414 
4415   // We do this the hard way, by blocking the thread.
4416   // Consider enforcing a minimum timeout value.
4417   struct timespec abst;
4418   compute_abstime(&abst, millis);
4419 
4420   int ret = OS_TIMEOUT;
4421   int status = pthread_mutex_lock(_mutex);
4422   assert_status(status == 0, status, "mutex_lock");
4423   guarantee (_nParked == 0, "invariant") ;
4424   ++_nParked ;
4425 
4426   // Object.wait(timo) will return because of
4427   // (a) notification
4428   // (b) timeout
4429   // (c) thread.interrupt
4430   //
4431   // Thread.interrupt and object.notify{All} both call Event::set.
4432   // That is, we treat thread.interrupt as a special case of notification.
4433   // The underlying Solaris implementation, cond_timedwait, admits
4434   // spurious/premature wakeups, but the JLS/JVM spec prevents the
4435   // JVM from making those visible to Java code.  As such, we must
4436   // filter out spurious wakeups.  We assume all ETIME returns are valid.
4437   //
4438   // TODO: properly differentiate simultaneous notify+interrupt.
4439   // In that case, we should propagate the notify to another waiter.
4440 
4441   while (_Event < 0) {
4442     status = os::Bsd::safe_cond_timedwait(_cond, _mutex, &abst);
4443     if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4444       pthread_cond_destroy (_cond);
4445       pthread_cond_init (_cond, NULL) ;
4446     }
4447     assert_status(status == 0 || status == EINTR ||
4448                   status == ETIMEDOUT,
4449                   status, "cond_timedwait");
4450     if (!FilterSpuriousWakeups) break ;                 // previous semantics
4451     if (status == ETIMEDOUT) break ;
4452     // We consume and ignore EINTR and spurious wakeups.
4453   }
4454   --_nParked ;
4455   if (_Event >= 0) {
4456      ret = OS_OK;
4457   }
4458   _Event = 0 ;
4459   status = pthread_mutex_unlock(_mutex);
4460   assert_status(status == 0, status, "mutex_unlock");
4461   assert (_nParked == 0, "invariant") ;
4462   // Paranoia to ensure our locked and lock-free paths interact
4463   // correctly with each other.
4464   OrderAccess::fence();
4465   return ret;
4466 }
4467 
4468 void os::PlatformEvent::unpark() {
4469   // Transitions for _Event:
4470   //    0 :=> 1
4471   //    1 :=> 1
4472   //   -1 :=> either 0 or 1; must signal target thread
4473   //          That is, we can safely transition _Event from -1 to either
4474   //          0 or 1. Forcing 1 is slightly more efficient for back-to-back
4475   //          unpark() calls.
4476   // See also: "Semaphores in Plan 9" by Mullender & Cox
4477   //
4478   // Note: Forcing a transition from "-1" to "1" on an unpark() means
4479   // that it will take two back-to-back park() calls for the owning
4480   // thread to block. This has the benefit of forcing a spurious return
4481   // from the first park() call after an unpark() call which will help
4482   // shake out uses of park() and unpark() without condition variables.
4483 
4484   if (Atomic::xchg(1, &_Event) >= 0) return;
4485 
4486   // Wait for the thread associated with the event to vacate
4487   int status = pthread_mutex_lock(_mutex);
4488   assert_status(status == 0, status, "mutex_lock");
4489   int AnyWaiters = _nParked;
4490   assert(AnyWaiters == 0 || AnyWaiters == 1, "invariant");
4491   if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
4492     AnyWaiters = 0;
4493     pthread_cond_signal(_cond);
4494   }
4495   status = pthread_mutex_unlock(_mutex);
4496   assert_status(status == 0, status, "mutex_unlock");
4497   if (AnyWaiters != 0) {
4498     status = pthread_cond_signal(_cond);
4499     assert_status(status == 0, status, "cond_signal");
4500   }
4501 
4502   // Note that we signal() _after dropping the lock for "immortal" Events.
4503   // This is safe and avoids a common class of  futile wakeups.  In rare
4504   // circumstances this can cause a thread to return prematurely from
4505   // cond_{timed}wait() but the spurious wakeup is benign and the victim will
4506   // simply re-test the condition and re-park itself.
4507 }
4508 
4509 
4510 // JSR166
4511 // -------------------------------------------------------
4512 
4513 /*
4514  * The solaris and bsd implementations of park/unpark are fairly
4515  * conservative for now, but can be improved. They currently use a
4516  * mutex/condvar pair, plus a a count.
4517  * Park decrements count if > 0, else does a condvar wait.  Unpark
4518  * sets count to 1 and signals condvar.  Only one thread ever waits
4519  * on the condvar. Contention seen when trying to park implies that someone
4520  * is unparking you, so don't wait. And spurious returns are fine, so there
4521  * is no need to track notifications.
4522  */
4523 
4524 #define MAX_SECS 100000000
4525 /*
4526  * This code is common to bsd and solaris and will be moved to a
4527  * common place in dolphin.
4528  *
4529  * The passed in time value is either a relative time in nanoseconds
4530  * or an absolute time in milliseconds. Either way it has to be unpacked
4531  * into suitable seconds and nanoseconds components and stored in the
4532  * given timespec structure.
4533  * Given time is a 64-bit value and the time_t used in the timespec is only
4534  * a signed-32-bit value (except on 64-bit Bsd) we have to watch for
4535  * overflow if times way in the future are given. Further on Solaris versions
4536  * prior to 10 there is a restriction (see cond_timedwait) that the specified
4537  * number of seconds, in abstime, is less than current_time  + 100,000,000.
4538  * As it will be 28 years before "now + 100000000" will overflow we can
4539  * ignore overflow and just impose a hard-limit on seconds using the value
4540  * of "now + 100,000,000". This places a limit on the timeout of about 3.17
4541  * years from "now".
4542  */
4543 
4544 static void unpackTime(struct timespec* absTime, bool isAbsolute, jlong time) {
4545   assert (time > 0, "convertTime");
4546 
4547   struct timeval now;
4548   int status = gettimeofday(&now, NULL);
4549   assert(status == 0, "gettimeofday");
4550 
4551   time_t max_secs = now.tv_sec + MAX_SECS;
4552 
4553   if (isAbsolute) {
4554     jlong secs = time / 1000;
4555     if (secs > max_secs) {
4556       absTime->tv_sec = max_secs;
4557     }
4558     else {
4559       absTime->tv_sec = secs;
4560     }
4561     absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
4562   }
4563   else {
4564     jlong secs = time / NANOSECS_PER_SEC;
4565     if (secs >= MAX_SECS) {
4566       absTime->tv_sec = max_secs;
4567       absTime->tv_nsec = 0;
4568     }
4569     else {
4570       absTime->tv_sec = now.tv_sec + secs;
4571       absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
4572       if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
4573         absTime->tv_nsec -= NANOSECS_PER_SEC;
4574         ++absTime->tv_sec; // note: this must be <= max_secs
4575       }
4576     }
4577   }
4578   assert(absTime->tv_sec >= 0, "tv_sec < 0");
4579   assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
4580   assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
4581   assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
4582 }
4583 
4584 void Parker::park(bool isAbsolute, jlong time) {
4585   // Ideally we'd do something useful while spinning, such
4586   // as calling unpackTime().
4587 
4588   // Optional fast-path check:
4589   // Return immediately if a permit is available.
4590   // We depend on Atomic::xchg() having full barrier semantics
4591   // since we are doing a lock-free update to _counter.
4592   if (Atomic::xchg(0, &_counter) > 0) return;
4593 
4594   Thread* thread = Thread::current();
4595   assert(thread->is_Java_thread(), "Must be JavaThread");
4596   JavaThread *jt = (JavaThread *)thread;
4597 
4598   // Optional optimization -- avoid state transitions if there's an interrupt pending.
4599   // Check interrupt before trying to wait
4600   if (Thread::is_interrupted(thread, false)) {
4601     return;
4602   }
4603 
4604   // Next, demultiplex/decode time arguments
4605   struct timespec absTime;
4606   if (time < 0 || (isAbsolute && time == 0) ) { // don't wait at all
4607     return;
4608   }
4609   if (time > 0) {
4610     unpackTime(&absTime, isAbsolute, time);
4611   }
4612 
4613 
4614   // Enter safepoint region
4615   // Beware of deadlocks such as 6317397.
4616   // The per-thread Parker:: mutex is a classic leaf-lock.
4617   // In particular a thread must never block on the Threads_lock while
4618   // holding the Parker:: mutex.  If safepoints are pending both the
4619   // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
4620   ThreadBlockInVM tbivm(jt);
4621 
4622   // Don't wait if cannot get lock since interference arises from
4623   // unblocking.  Also. check interrupt before trying wait
4624   if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
4625     return;
4626   }
4627 
4628   int status ;
4629   if (_counter > 0)  { // no wait needed
4630     _counter = 0;
4631     status = pthread_mutex_unlock(_mutex);
4632     assert (status == 0, "invariant") ;
4633     // Paranoia to ensure our locked and lock-free paths interact
4634     // correctly with each other and Java-level accesses.
4635     OrderAccess::fence();
4636     return;
4637   }
4638 
4639 #ifdef ASSERT
4640   // Don't catch signals while blocked; let the running threads have the signals.
4641   // (This allows a debugger to break into the running thread.)
4642   sigset_t oldsigs;
4643   sigset_t* allowdebug_blocked = os::Bsd::allowdebug_blocked_signals();
4644   pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
4645 #endif
4646 
4647   OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
4648   jt->set_suspend_equivalent();
4649   // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
4650 
4651   if (time == 0) {
4652     status = pthread_cond_wait (_cond, _mutex) ;
4653   } else {
4654     status = os::Bsd::safe_cond_timedwait (_cond, _mutex, &absTime) ;
4655     if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4656       pthread_cond_destroy (_cond) ;
4657       pthread_cond_init    (_cond, NULL);
4658     }
4659   }
4660   assert_status(status == 0 || status == EINTR ||
4661                 status == ETIMEDOUT,
4662                 status, "cond_timedwait");
4663 
4664 #ifdef ASSERT
4665   pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
4666 #endif
4667 
4668   _counter = 0 ;
4669   status = pthread_mutex_unlock(_mutex) ;
4670   assert_status(status == 0, status, "invariant") ;
4671   // Paranoia to ensure our locked and lock-free paths interact
4672   // correctly with each other and Java-level accesses.
4673   OrderAccess::fence();
4674 
4675   // If externally suspended while waiting, re-suspend
4676   if (jt->handle_special_suspend_equivalent_condition()) {
4677     jt->java_suspend_self();
4678   }
4679 }
4680 
4681 void Parker::unpark() {
4682   int s, status ;
4683   status = pthread_mutex_lock(_mutex);
4684   assert (status == 0, "invariant") ;
4685   s = _counter;
4686   _counter = 1;
4687   if (s < 1) {
4688      if (WorkAroundNPTLTimedWaitHang) {
4689         status = pthread_cond_signal (_cond) ;
4690         assert (status == 0, "invariant") ;
4691         status = pthread_mutex_unlock(_mutex);
4692         assert (status == 0, "invariant") ;
4693      } else {
4694         status = pthread_mutex_unlock(_mutex);
4695         assert (status == 0, "invariant") ;
4696         status = pthread_cond_signal (_cond) ;
4697         assert (status == 0, "invariant") ;
4698      }
4699   } else {
4700     pthread_mutex_unlock(_mutex);
4701     assert (status == 0, "invariant") ;
4702   }
4703 }
4704 
4705 
4706 /* Darwin has no "environ" in a dynamic library. */
4707 #ifdef __APPLE__
4708 #include <crt_externs.h>
4709 #define environ (*_NSGetEnviron())
4710 #else
4711 extern char** environ;
4712 #endif
4713 
4714 // Run the specified command in a separate process. Return its exit value,
4715 // or -1 on failure (e.g. can't fork a new process).
4716 // Unlike system(), this function can be called from signal handler. It
4717 // doesn't block SIGINT et al.
4718 int os::fork_and_exec(char* cmd, bool use_vfork_if_available) {
4719   const char * argv[4] = {"sh", "-c", cmd, NULL};
4720 
4721   // fork() in BsdThreads/NPTL is not async-safe. It needs to run
4722   // pthread_atfork handlers and reset pthread library. All we need is a
4723   // separate process to execve. Make a direct syscall to fork process.
4724   // On IA64 there's no fork syscall, we have to use fork() and hope for
4725   // the best...
4726   pid_t pid = fork();
4727 
4728   if (pid < 0) {
4729     // fork failed
4730     return -1;
4731 
4732   } else if (pid == 0) {
4733     // child process
4734 
4735     // execve() in BsdThreads will call pthread_kill_other_threads_np()
4736     // first to kill every thread on the thread list. Because this list is
4737     // not reset by fork() (see notes above), execve() will instead kill
4738     // every thread in the parent process. We know this is the only thread
4739     // in the new process, so make a system call directly.
4740     // IA64 should use normal execve() from glibc to match the glibc fork()
4741     // above.
4742     execve("/bin/sh", (char* const*)argv, environ);
4743 
4744     // execve failed
4745     _exit(-1);
4746 
4747   } else  {
4748     // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4749     // care about the actual exit code, for now.
4750 
4751     int status;
4752 
4753     // Wait for the child process to exit.  This returns immediately if
4754     // the child has already exited. */
4755     while (waitpid(pid, &status, 0) < 0) {
4756         switch (errno) {
4757         case ECHILD: return 0;
4758         case EINTR: break;
4759         default: return -1;
4760         }
4761     }
4762 
4763     if (WIFEXITED(status)) {
4764        // The child exited normally; get its exit code.
4765        return WEXITSTATUS(status);
4766     } else if (WIFSIGNALED(status)) {
4767        // The child exited because of a signal
4768        // The best value to return is 0x80 + signal number,
4769        // because that is what all Unix shells do, and because
4770        // it allows callers to distinguish between process exit and
4771        // process death by signal.
4772        return 0x80 + WTERMSIG(status);
4773     } else {
4774        // Unknown exit code; pass it through
4775        return status;
4776     }
4777   }
4778 }
4779 
4780 // is_headless_jre()
4781 //
4782 // Test for the existence of xawt/libmawt.so or libawt_xawt.so
4783 // in order to report if we are running in a headless jre
4784 //
4785 // Since JDK8 xawt/libmawt.so was moved into the same directory
4786 // as libawt.so, and renamed libawt_xawt.so
4787 //
4788 bool os::is_headless_jre() {
4789 #ifdef __APPLE__
4790     // We no longer build headless-only on Mac OS X
4791     return false;
4792 #else
4793     struct stat statbuf;
4794     char buf[MAXPATHLEN];
4795     char libmawtpath[MAXPATHLEN];
4796     const char *xawtstr  = "/xawt/libmawt" JNI_LIB_SUFFIX;
4797     const char *new_xawtstr = "/libawt_xawt" JNI_LIB_SUFFIX;
4798     char *p;
4799 
4800     // Get path to libjvm.so
4801     os::jvm_path(buf, sizeof(buf));
4802 
4803     // Get rid of libjvm.so
4804     p = strrchr(buf, '/');
4805     if (p == NULL) return false;
4806     else *p = '\0';
4807 
4808     // Get rid of client or server
4809     p = strrchr(buf, '/');
4810     if (p == NULL) return false;
4811     else *p = '\0';
4812 
4813     // check xawt/libmawt.so
4814     strcpy(libmawtpath, buf);
4815     strcat(libmawtpath, xawtstr);
4816     if (::stat(libmawtpath, &statbuf) == 0) return false;
4817 
4818     // check libawt_xawt.so
4819     strcpy(libmawtpath, buf);
4820     strcat(libmawtpath, new_xawtstr);
4821     if (::stat(libmawtpath, &statbuf) == 0) return false;
4822 
4823     return true;
4824 #endif
4825 }
4826 
4827 // Get the default path to the core file
4828 // Returns the length of the string
4829 int os::get_core_path(char* buffer, size_t bufferSize) {
4830   int n = jio_snprintf(buffer, bufferSize, "/cores");
4831 
4832   // Truncate if theoretical string was longer than bufferSize
4833   n = MIN2(n, (int)bufferSize);
4834 
4835   return n;
4836 }
4837 
4838 #ifndef PRODUCT
4839 void TestReserveMemorySpecial_test() {
4840   // No tests available for this platform
4841 }
4842 #endif