1 /*
   2  * Copyright (c) 2012, 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 #include "precompiled.hpp"
  26 #include "jvm.h"
  27 #include "memory/allocation.inline.hpp"
  28 #include "os_aix.inline.hpp"
  29 #include "runtime/os.hpp"
  30 #include "runtime/os_perf.hpp"
  31 
  32 #include CPU_HEADER(vm_version_ext)
  33 
  34 #include <stdio.h>
  35 #include <stdarg.h>
  36 #include <unistd.h>
  37 #include <errno.h>
  38 #include <string.h>
  39 #include <sys/resource.h>
  40 #include <sys/types.h>
  41 #include <sys/stat.h>
  42 #include <dirent.h>
  43 #include <stdlib.h>
  44 #include <dlfcn.h>
  45 #include <pthread.h>
  46 #include <limits.h>
  47 
  48 /**
  49    /proc/[number]/stat
  50               Status information about the process.  This is used by ps(1).  It is defined in /usr/src/linux/fs/proc/array.c.
  51 
  52               The fields, in order, with their proper scanf(3) format specifiers, are:
  53 
  54               1. pid %d The process id.
  55 
  56               2. comm %s
  57                      The filename of the executable, in parentheses.  This is visible whether or not the executable is swapped out.
  58 
  59               3. state %c
  60                      One  character  from  the  string "RSDZTW" where R is running, S is sleeping in an interruptible wait, D is waiting in uninterruptible disk
  61                      sleep, Z is zombie, T is traced or stopped (on a signal), and W is paging.
  62 
  63               4. ppid %d
  64                      The PID of the parent.
  65 
  66               5. pgrp %d
  67                      The process group ID of the process.
  68 
  69               6. session %d
  70                      The session ID of the process.
  71 
  72               7. tty_nr %d
  73                      The tty the process uses.
  74 
  75               8. tpgid %d
  76                      The process group ID of the process which currently owns the tty that the process is connected to.
  77 
  78               9. flags %lu
  79                      The flags of the process.  The math bit is decimal 4, and the traced bit is decimal 10.
  80 
  81               10. minflt %lu
  82                      The number of minor faults the process has made which have not required loading a memory page from disk.
  83 
  84               11. cminflt %lu
  85                      The number of minor faults that the process's waited-for children have made.
  86 
  87               12. majflt %lu
  88                      The number of major faults the process has made which have required loading a memory page from disk.
  89 
  90               13. cmajflt %lu
  91                      The number of major faults that the process's waited-for children have made.
  92 
  93               14. utime %lu
  94                      The number of jiffies that this process has been scheduled in user mode.
  95 
  96               15. stime %lu
  97                      The number of jiffies that this process has been scheduled in kernel mode.
  98 
  99               16. cutime %ld
 100                      The number of jiffies that this process's waited-for children have been scheduled in user mode. (See also times(2).)
 101 
 102               17. cstime %ld
 103                      The number of jiffies that this process' waited-for children have been scheduled in kernel mode.
 104 
 105               18. priority %ld
 106                      The standard nice value, plus fifteen.  The value is never negative in the kernel.
 107 
 108               19. nice %ld
 109                      The nice value ranges from 19 (nicest) to -19 (not nice to others).
 110 
 111               20. 0 %ld  This value is hard coded to 0 as a placeholder for a removed field.
 112 
 113               21. itrealvalue %ld
 114                      The time in jiffies before the next SIGALRM is sent to the process due to an interval timer.
 115 
 116               22. starttime %lu
 117                      The time in jiffies the process started after system boot.
 118 
 119               23. vsize %lu
 120                      Virtual memory size in bytes.
 121 
 122               24. rss %ld
 123                      Resident Set Size: number of pages the process has in real memory, minus 3 for administrative purposes. This is just the pages which  count
 124                      towards text, data, or stack space.  This does not include pages which have not been demand-loaded in, or which are swapped out.
 125 
 126               25. rlim %lu
 127                      Current limit in bytes on the rss of the process (usually 4294967295 on i386).
 128 
 129               26. startcode %lu
 130                      The address above which program text can run.
 131 
 132               27. endcode %lu
 133                      The address below which program text can run.
 134 
 135               28. startstack %lu
 136                      The address of the start of the stack.
 137 
 138               29. kstkesp %lu
 139                      The current value of esp (stack pointer), as found in the kernel stack page for the process.
 140 
 141               30. kstkeip %lu
 142                      The current EIP (instruction pointer).
 143 
 144               31. signal %lu
 145                      The bitmap of pending signals (usually 0).
 146 
 147               32. blocked %lu
 148                      The bitmap of blocked signals (usually 0, 2 for shells).
 149 
 150               33. sigignore %lu
 151                      The bitmap of ignored signals.
 152 
 153               34. sigcatch %lu
 154                      The bitmap of catched signals.
 155 
 156               35. wchan %lu
 157                      This  is the "channel" in which the process is waiting.  It is the address of a system call, and can be looked up in a namelist if you need
 158                      a textual name.  (If you have an up-to-date /etc/psdatabase, then try ps -l to see the WCHAN field in action.)
 159 
 160               36. nswap %lu
 161                      Number of pages swapped - not maintained.
 162 
 163               37. cnswap %lu
 164                      Cumulative nswap for child processes.
 165 
 166               38. exit_signal %d
 167                      Signal to be sent to parent when we die.
 168 
 169               39. processor %d
 170                      CPU number last executed on.
 171 
 172 
 173 
 174  ///// SSCANF FORMAT STRING. Copy and use.
 175 
 176 field:        1  2  3  4  5  6  7  8  9   10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38 39
 177 format:       %d %s %c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld %lu %lu %ld %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %d %d
 178 
 179 
 180 */
 181 
 182 /**
 183  * For platforms that have them, when declaring
 184  * a printf-style function,
 185  *   formatSpec is the parameter number (starting at 1)
 186  *       that is the format argument ("%d pid %s")
 187  *   params is the parameter number where the actual args to
 188  *       the format starts. If the args are in a va_list, this
 189  *       should be 0.
 190  */
 191 #ifndef PRINTF_ARGS
 192 #  define PRINTF_ARGS(formatSpec,  params) ATTRIBUTE_PRINTF(formatSpec, params)
 193 #endif
 194 
 195 #ifndef SCANF_ARGS
 196 #  define SCANF_ARGS(formatSpec,   params) ATTRIBUTE_SCANF(formatSpec, params)
 197 #endif
 198 
 199 #ifndef _PRINTFMT_
 200 #  define _PRINTFMT_
 201 #endif
 202 
 203 #ifndef _SCANFMT_
 204 #  define _SCANFMT_
 205 #endif
 206 
 207 
 208 struct CPUPerfTicks {
 209   uint64_t  used;
 210   uint64_t  usedKernel;
 211   uint64_t  total;
 212 };
 213 
 214 typedef enum {
 215   CPU_LOAD_VM_ONLY,
 216   CPU_LOAD_GLOBAL,
 217 } CpuLoadTarget;
 218 
 219 enum {
 220   UNDETECTED,
 221   UNDETECTABLE,
 222   LINUX26_NPTL,
 223   BAREMETAL
 224 };
 225 
 226 struct CPUPerfCounters {
 227   int   nProcs;
 228   CPUPerfTicks jvmTicks;
 229   CPUPerfTicks* cpus;
 230 };
 231 
 232 static double get_cpu_load(int which_logical_cpu, CPUPerfCounters* counters, double* pkernelLoad, CpuLoadTarget target);
 233 
 234 /** reads /proc/<pid>/stat data, with some checks and some skips.
 235  *  Ensure that 'fmt' does _NOT_ contain the first two "%d %s"
 236  */
 237 static int SCANF_ARGS(2, 0) vread_statdata(const char* procfile, _SCANFMT_ const char* fmt, va_list args) {
 238   FILE*f;
 239   int n;
 240   char buf[2048];
 241 
 242   if ((f = fopen(procfile, "r")) == NULL) {
 243     return -1;
 244   }
 245 
 246   if ((n = fread(buf, 1, sizeof(buf), f)) != -1) {
 247     char *tmp;
 248 
 249     buf[n-1] = '\0';
 250     /** skip through pid and exec name. */
 251     if ((tmp = strrchr(buf, ')')) != NULL) {
 252       // skip the ')' and the following space
 253       // but check that buffer is long enough
 254       tmp += 2;
 255       if (tmp < buf + n) {
 256         n = vsscanf(tmp, fmt, args);
 257       }
 258     }
 259   }
 260 
 261   fclose(f);
 262 
 263   return n;
 264 }
 265 
 266 static int SCANF_ARGS(2, 3) read_statdata(const char* procfile, _SCANFMT_ const char* fmt, ...) {
 267   int   n;
 268   va_list args;
 269 
 270   va_start(args, fmt);
 271   n = vread_statdata(procfile, fmt, args);
 272   va_end(args);
 273   return n;
 274 }
 275 
 276 /**
 277  * on Linux we got the ticks related information from /proc/stat
 278  * this does not work on AIX, libperfstat might be an alternative
 279  */
 280 static OSReturn get_total_ticks(int which_logical_cpu, CPUPerfTicks* pticks) {
 281   return OS_ERR;
 282 }
 283 
 284 /** read user and system ticks from a named procfile, assumed to be in 'stat' format then. */
 285 static int read_ticks(const char* procfile, uint64_t* userTicks, uint64_t* systemTicks) {
 286   return read_statdata(procfile, "%*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u " UINT64_FORMAT " " UINT64_FORMAT,
 287     userTicks, systemTicks);
 288 }
 289 
 290 /**
 291  * Return the number of ticks spent in any of the processes belonging
 292  * to the JVM on any CPU.
 293  */
 294 static OSReturn get_jvm_ticks(CPUPerfTicks* pticks) {
 295   return OS_ERR;
 296 }
 297 
 298 /**
 299  * Return the load of the CPU as a double. 1.0 means the CPU process uses all
 300  * available time for user or system processes, 0.0 means the CPU uses all time
 301  * being idle.
 302  *
 303  * Returns a negative value if there is a problem in determining the CPU load.
 304  */
 305 static double get_cpu_load(int which_logical_cpu, CPUPerfCounters* counters, double* pkernelLoad, CpuLoadTarget target) {
 306   uint64_t udiff, kdiff, tdiff;
 307   CPUPerfTicks* pticks;
 308   CPUPerfTicks  tmp;
 309   double user_load;
 310 
 311   *pkernelLoad = 0.0;
 312 
 313   if (target == CPU_LOAD_VM_ONLY) {
 314     pticks = &counters->jvmTicks;
 315   } else if (-1 == which_logical_cpu) {
 316     pticks = &counters->cpus[counters->nProcs];
 317   } else {
 318     pticks = &counters->cpus[which_logical_cpu];
 319   }
 320 
 321   tmp = *pticks;
 322 
 323   if (target == CPU_LOAD_VM_ONLY) {
 324     if (get_jvm_ticks(pticks) != OS_OK) {
 325       return -1.0;
 326     }
 327   } else if (get_total_ticks(which_logical_cpu, pticks) != OS_OK) {
 328     return -1.0;
 329   }
 330 
 331   // seems like we sometimes end up with less kernel ticks when
 332   // reading /proc/self/stat a second time, timing issue between cpus?
 333   if (pticks->usedKernel < tmp.usedKernel) {
 334     kdiff = 0;
 335   } else {
 336     kdiff = pticks->usedKernel - tmp.usedKernel;
 337   }
 338   tdiff = pticks->total - tmp.total;
 339   udiff = pticks->used - tmp.used;
 340 
 341   if (tdiff == 0) {
 342     return 0.0;
 343   } else if (tdiff < (udiff + kdiff)) {
 344     tdiff = udiff + kdiff;
 345   }
 346   *pkernelLoad = (kdiff / (double)tdiff);
 347   // BUG9044876, normalize return values to sane values
 348   *pkernelLoad = MAX2<double>(*pkernelLoad, 0.0);
 349   *pkernelLoad = MIN2<double>(*pkernelLoad, 1.0);
 350 
 351   user_load = (udiff / (double)tdiff);
 352   user_load = MAX2<double>(user_load, 0.0);
 353   user_load = MIN2<double>(user_load, 1.0);
 354 
 355   return user_load;
 356 }
 357 
 358 static int SCANF_ARGS(1, 2) parse_stat(_SCANFMT_ const char* fmt, ...) {
 359   return OS_ERR;
 360 }
 361 
 362 static int get_noof_context_switches(uint64_t* switches) {
 363   return parse_stat("ctxt " UINT64_FORMAT "\n", switches);
 364 }
 365 
 366 /** returns boot time in _seconds_ since epoch */
 367 static int get_boot_time(uint64_t* time) {
 368   return parse_stat("btime " UINT64_FORMAT "\n", time);
 369 }
 370 
 371 static int perf_context_switch_rate(double* rate) {
 372   static pthread_mutex_t contextSwitchLock = PTHREAD_MUTEX_INITIALIZER;
 373   static uint64_t      lastTime;
 374   static uint64_t      lastSwitches;
 375   static double        lastRate;
 376 
 377   uint64_t lt = 0;
 378   int res = 0;
 379 
 380   if (lastTime == 0) {
 381     uint64_t tmp;
 382     if (get_boot_time(&tmp) < 0) {
 383       return OS_ERR;
 384     }
 385     lt = tmp * 1000;
 386   }
 387 
 388   res = OS_OK;
 389 
 390   pthread_mutex_lock(&contextSwitchLock);
 391   {
 392 
 393     uint64_t sw;
 394     s8 t, d;
 395 
 396     if (lastTime == 0) {
 397       lastTime = lt;
 398     }
 399 
 400     t = os::javaTimeMillis();
 401     d = t - lastTime;
 402 
 403     if (d == 0) {
 404       *rate = lastRate;
 405     } else if (!get_noof_context_switches(&sw)) {
 406       *rate      = ( (double)(sw - lastSwitches) / d ) * 1000;
 407       lastRate     = *rate;
 408       lastSwitches = sw;
 409       lastTime     = t;
 410     } else {
 411       *rate = 0;
 412       res   = OS_ERR;
 413     }
 414     if (*rate <= 0) {
 415       *rate = 0;
 416       lastRate = 0;
 417     }
 418   }
 419   pthread_mutex_unlock(&contextSwitchLock);
 420 
 421   return res;
 422 }
 423 
 424 class CPUPerformanceInterface::CPUPerformance : public CHeapObj<mtInternal> {
 425   friend class CPUPerformanceInterface;
 426  private:
 427   CPUPerfCounters _counters;
 428 
 429   int cpu_load(int which_logical_cpu, double* cpu_load);
 430   int context_switch_rate(double* rate);
 431   int cpu_load_total_process(double* cpu_load);
 432   int cpu_loads_process(double* pjvmUserLoad, double* pjvmKernelLoad, double* psystemTotalLoad);
 433 
 434  public:
 435   CPUPerformance();
 436   bool initialize();
 437   ~CPUPerformance();
 438 };
 439 
 440 CPUPerformanceInterface::CPUPerformance::CPUPerformance() {
 441   _counters.nProcs = os::active_processor_count();
 442   _counters.cpus = NULL;
 443 }
 444 
 445 bool CPUPerformanceInterface::CPUPerformance::initialize() {
 446   size_t tick_array_size = (_counters.nProcs +1) * sizeof(CPUPerfTicks);
 447   _counters.cpus = (CPUPerfTicks*)NEW_C_HEAP_ARRAY(char, tick_array_size, mtInternal);
 448   if (NULL == _counters.cpus) {
 449     return false;
 450   }
 451   memset(_counters.cpus, 0, tick_array_size);
 452 
 453   // For the CPU load total
 454   get_total_ticks(-1, &_counters.cpus[_counters.nProcs]);
 455 
 456   // For each CPU
 457   for (int i = 0; i < _counters.nProcs; i++) {
 458     get_total_ticks(i, &_counters.cpus[i]);
 459   }
 460   // For JVM load
 461   get_jvm_ticks(&_counters.jvmTicks);
 462 
 463   // initialize context switch system
 464   // the double is only for init
 465   double init_ctx_switch_rate;
 466   perf_context_switch_rate(&init_ctx_switch_rate);
 467 
 468   return true;
 469 }
 470 
 471 CPUPerformanceInterface::CPUPerformance::~CPUPerformance() {
 472   if (_counters.cpus != NULL) {
 473     FREE_C_HEAP_ARRAY(char, _counters.cpus);
 474   }
 475 }
 476 
 477 int CPUPerformanceInterface::CPUPerformance::cpu_load(int which_logical_cpu, double* cpu_load) {
 478   double u, s;
 479   u = get_cpu_load(which_logical_cpu, &_counters, &s, CPU_LOAD_GLOBAL);
 480   if (u < 0) {
 481     *cpu_load = 0.0;
 482     return OS_ERR;
 483   }
 484   // Cap total systemload to 1.0
 485   *cpu_load = MIN2<double>((u + s), 1.0);
 486   return OS_OK;
 487 }
 488 
 489 int CPUPerformanceInterface::CPUPerformance::cpu_load_total_process(double* cpu_load) {
 490   double u, s;
 491   u = get_cpu_load(-1, &_counters, &s, CPU_LOAD_VM_ONLY);
 492   if (u < 0) {
 493     *cpu_load = 0.0;
 494     return OS_ERR;
 495   }
 496   *cpu_load = u + s;
 497   return OS_OK;
 498 }
 499 
 500 int CPUPerformanceInterface::CPUPerformance::cpu_loads_process(double* pjvmUserLoad, double* pjvmKernelLoad, double* psystemTotalLoad) {
 501   double u, s, t;
 502 
 503   assert(pjvmUserLoad != NULL, "pjvmUserLoad not inited");
 504   assert(pjvmKernelLoad != NULL, "pjvmKernelLoad not inited");
 505   assert(psystemTotalLoad != NULL, "psystemTotalLoad not inited");
 506 
 507   u = get_cpu_load(-1, &_counters, &s, CPU_LOAD_VM_ONLY);
 508   if (u < 0) {
 509     *pjvmUserLoad = 0.0;
 510     *pjvmKernelLoad = 0.0;
 511     *psystemTotalLoad = 0.0;
 512     return OS_ERR;
 513   }
 514 
 515   cpu_load(-1, &t);
 516   // clamp at user+system and 1.0
 517   if (u + s > t) {
 518     t = MIN2<double>(u + s, 1.0);
 519   }
 520 
 521   *pjvmUserLoad = u;
 522   *pjvmKernelLoad = s;
 523   *psystemTotalLoad = t;
 524 
 525   return OS_OK;
 526 }
 527 
 528 int CPUPerformanceInterface::CPUPerformance::context_switch_rate(double* rate) {
 529   return perf_context_switch_rate(rate);
 530 }
 531 
 532 CPUPerformanceInterface::CPUPerformanceInterface() {
 533   _impl = NULL;
 534 }
 535 
 536 bool CPUPerformanceInterface::initialize() {
 537   _impl = new CPUPerformanceInterface::CPUPerformance();
 538   return NULL == _impl ? false : _impl->initialize();
 539 }
 540 
 541 CPUPerformanceInterface::~CPUPerformanceInterface() {
 542   if (_impl != NULL) {
 543     delete _impl;
 544   }
 545 }
 546 
 547 int CPUPerformanceInterface::cpu_load(int which_logical_cpu, double* cpu_load) const {
 548   return _impl->cpu_load(which_logical_cpu, cpu_load);
 549 }
 550 
 551 int CPUPerformanceInterface::cpu_load_total_process(double* cpu_load) const {
 552   return _impl->cpu_load_total_process(cpu_load);
 553 }
 554 
 555 int CPUPerformanceInterface::cpu_loads_process(double* pjvmUserLoad, double* pjvmKernelLoad, double* psystemTotalLoad) const {
 556   return _impl->cpu_loads_process(pjvmUserLoad, pjvmKernelLoad, psystemTotalLoad);
 557 }
 558 
 559 int CPUPerformanceInterface::context_switch_rate(double* rate) const {
 560   return _impl->context_switch_rate(rate);
 561 }
 562 
 563 class SystemProcessInterface::SystemProcesses : public CHeapObj<mtInternal> {
 564   friend class SystemProcessInterface;
 565  private:
 566   class ProcessIterator : public CHeapObj<mtInternal> {
 567     friend class SystemProcessInterface::SystemProcesses;
 568    private:
 569     DIR*           _dir;
 570     struct dirent* _entry;
 571     bool           _valid;
 572     char           _exeName[PATH_MAX];
 573     char           _exePath[PATH_MAX];
 574 
 575     ProcessIterator();
 576     ~ProcessIterator();
 577     bool initialize();
 578 
 579     bool is_valid() const { return _valid; }
 580     bool is_valid_entry(struct dirent* entry) const;
 581     bool is_dir(const char* name) const;
 582     int  fsize(const char* name, uint64_t& size) const;
 583 
 584     char* allocate_string(const char* str) const;
 585     void  get_exe_name();
 586     char* get_exe_path();
 587     char* get_cmdline();
 588 
 589     int current(SystemProcess* process_info);
 590     int next_process();
 591   };
 592 
 593   ProcessIterator* _iterator;
 594   SystemProcesses();
 595   bool initialize();
 596   ~SystemProcesses();
 597 
 598   //information about system processes
 599   int system_processes(SystemProcess** system_processes, int* no_of_sys_processes) const;
 600 };
 601 
 602 bool SystemProcessInterface::SystemProcesses::ProcessIterator::is_dir(const char* name) const {
 603   struct stat mystat;
 604   int ret_val = 0;
 605 
 606   ret_val = stat(name, &mystat);
 607   if (ret_val < 0) {
 608     return false;
 609   }
 610   ret_val = S_ISDIR(mystat.st_mode);
 611   return ret_val > 0;
 612 }
 613 
 614 int SystemProcessInterface::SystemProcesses::ProcessIterator::fsize(const char* name, uint64_t& size) const {
 615   assert(name != NULL, "name pointer is NULL!");
 616   size = 0;
 617   struct stat fbuf;
 618 
 619   if (stat(name, &fbuf) < 0) {
 620     return OS_ERR;
 621   }
 622   size = fbuf.st_size;
 623   return OS_OK;
 624 }
 625 
 626 // if it has a numeric name, is a directory and has a 'stat' file in it
 627 bool SystemProcessInterface::SystemProcesses::ProcessIterator::is_valid_entry(struct dirent* entry) const {
 628   char buffer[PATH_MAX];
 629   uint64_t size = 0;
 630 
 631   if (atoi(entry->d_name) != 0) {
 632     jio_snprintf(buffer, PATH_MAX, "/proc/%s", entry->d_name);
 633     buffer[PATH_MAX - 1] = '\0';
 634 
 635     if (is_dir(buffer)) {
 636       jio_snprintf(buffer, PATH_MAX, "/proc/%s/stat", entry->d_name);
 637       buffer[PATH_MAX - 1] = '\0';
 638       if (fsize(buffer, size) != OS_ERR) {
 639         return true;
 640       }
 641     }
 642   }
 643   return false;
 644 }
 645 
 646 // get exe-name from /proc/<pid>/stat
 647 void SystemProcessInterface::SystemProcesses::ProcessIterator::get_exe_name() {
 648   FILE* fp;
 649   char  buffer[PATH_MAX];
 650 
 651   jio_snprintf(buffer, PATH_MAX, "/proc/%s/stat", _entry->d_name);
 652   buffer[PATH_MAX - 1] = '\0';
 653   if ((fp = fopen(buffer, "r")) != NULL) {
 654     if (fgets(buffer, PATH_MAX, fp) != NULL) {
 655       char* start, *end;
 656       // exe-name is between the first pair of ( and )
 657       start = strchr(buffer, '(');
 658       if (start != NULL && start[1] != '\0') {
 659         start++;
 660         end = strrchr(start, ')');
 661         if (end != NULL) {
 662           size_t len;
 663           len = MIN2<size_t>(end - start, sizeof(_exeName) - 1);
 664           memcpy(_exeName, start, len);
 665           _exeName[len] = '\0';
 666         }
 667       }
 668     }
 669     fclose(fp);
 670   }
 671 }
 672 
 673 // get command line from /proc/<pid>/cmdline
 674 char* SystemProcessInterface::SystemProcesses::ProcessIterator::get_cmdline() {
 675   FILE* fp;
 676   char  buffer[PATH_MAX];
 677   char* cmdline = NULL;
 678 
 679   jio_snprintf(buffer, PATH_MAX, "/proc/%s/cmdline", _entry->d_name);
 680   buffer[PATH_MAX - 1] = '\0';
 681   if ((fp = fopen(buffer, "r")) != NULL) {
 682     size_t size = 0;
 683     char   dummy;
 684 
 685     // find out how long the file is (stat always returns 0)
 686     while (fread(&dummy, 1, 1, fp) == 1) {
 687       size++;
 688     }
 689     if (size > 0) {
 690       cmdline = NEW_C_HEAP_ARRAY(char, size + 1, mtInternal);
 691       if (cmdline != NULL) {
 692         cmdline[0] = '\0';
 693         if (fseek(fp, 0, SEEK_SET) == 0) {
 694           if (fread(cmdline, 1, size, fp) == size) {
 695             // the file has the arguments separated by '\0',
 696             // so we translate '\0' to ' '
 697             for (size_t i = 0; i < size; i++) {
 698               if (cmdline[i] == '\0') {
 699                 cmdline[i] = ' ';
 700               }
 701             }
 702             cmdline[size] = '\0';
 703           }
 704         }
 705       }
 706     }
 707     fclose(fp);
 708   }
 709   return cmdline;
 710 }
 711 
 712 // get full path to exe from /proc/<pid>/exe symlink
 713 char* SystemProcessInterface::SystemProcesses::ProcessIterator::get_exe_path() {
 714   char buffer[PATH_MAX];
 715 
 716   jio_snprintf(buffer, PATH_MAX, "/proc/%s/exe", _entry->d_name);
 717   buffer[PATH_MAX - 1] = '\0';
 718   return realpath(buffer, _exePath);
 719 }
 720 
 721 char* SystemProcessInterface::SystemProcesses::ProcessIterator::allocate_string(const char* str) const {
 722   if (str != NULL) {
 723     return os::strdup_check_oom(str, mtInternal);
 724   }
 725   return NULL;
 726 }
 727 
 728 int SystemProcessInterface::SystemProcesses::ProcessIterator::current(SystemProcess* process_info) {
 729   if (!is_valid()) {
 730     return OS_ERR;
 731   }
 732 
 733   process_info->set_pid(atoi(_entry->d_name));
 734 
 735   get_exe_name();
 736   process_info->set_name(allocate_string(_exeName));
 737 
 738   if (get_exe_path() != NULL) {
 739      process_info->set_path(allocate_string(_exePath));
 740   }
 741 
 742   char* cmdline = NULL;
 743   cmdline = get_cmdline();
 744   if (cmdline != NULL) {
 745     process_info->set_command_line(allocate_string(cmdline));
 746     FREE_C_HEAP_ARRAY(char, cmdline);
 747   }
 748 
 749   return OS_OK;
 750 }
 751 
 752 int SystemProcessInterface::SystemProcesses::ProcessIterator::next_process() {
 753   if (!is_valid()) {
 754     return OS_ERR;
 755   }
 756 
 757   do {
 758     _entry = os::readdir(_dir);
 759     if (_entry == NULL) {
 760       // Error or reached end.  Could use errno to distinguish those cases.
 761       _valid = false;
 762       return OS_ERR;
 763     }
 764   } while(!is_valid_entry(_entry));
 765 
 766   _valid = true;
 767   return OS_OK;
 768 }
 769 
 770 SystemProcessInterface::SystemProcesses::ProcessIterator::ProcessIterator() {
 771   _dir = NULL;
 772   _entry = NULL;
 773   _valid = false;
 774 }
 775 
 776 bool SystemProcessInterface::SystemProcesses::ProcessIterator::initialize() {
 777   // Not yet implemented.
 778   return false;
 779 }
 780 
 781 SystemProcessInterface::SystemProcesses::ProcessIterator::~ProcessIterator() {
 782   if (_dir != NULL) {
 783     os::closedir(_dir);
 784   }
 785 }
 786 
 787 SystemProcessInterface::SystemProcesses::SystemProcesses() {
 788   _iterator = NULL;
 789 }
 790 
 791 bool SystemProcessInterface::SystemProcesses::initialize() {
 792   _iterator = new SystemProcessInterface::SystemProcesses::ProcessIterator();
 793   return NULL == _iterator ? false : _iterator->initialize();
 794 }
 795 
 796 SystemProcessInterface::SystemProcesses::~SystemProcesses() {
 797   if (_iterator != NULL) {
 798     delete _iterator;
 799   }
 800 }
 801 
 802 int SystemProcessInterface::SystemProcesses::system_processes(SystemProcess** system_processes, int* no_of_sys_processes) const {
 803   assert(system_processes != NULL, "system_processes pointer is NULL!");
 804   assert(no_of_sys_processes != NULL, "system_processes counter pointers is NULL!");
 805   assert(_iterator != NULL, "iterator is NULL!");
 806 
 807   // initialize pointers
 808   *no_of_sys_processes = 0;
 809   *system_processes = NULL;
 810 
 811   while (_iterator->is_valid()) {
 812     SystemProcess* tmp = new SystemProcess();
 813     _iterator->current(tmp);
 814 
 815     //if already existing head
 816     if (*system_processes != NULL) {
 817       //move "first to second"
 818       tmp->set_next(*system_processes);
 819     }
 820     // new head
 821     *system_processes = tmp;
 822     // increment
 823     (*no_of_sys_processes)++;
 824     // step forward
 825     _iterator->next_process();
 826   }
 827   return OS_OK;
 828 }
 829 
 830 int SystemProcessInterface::system_processes(SystemProcess** system_procs, int* no_of_sys_processes) const {
 831   return _impl->system_processes(system_procs, no_of_sys_processes);
 832 }
 833 
 834 SystemProcessInterface::SystemProcessInterface() {
 835   _impl = NULL;
 836 }
 837 
 838 bool SystemProcessInterface::initialize() {
 839   _impl = new SystemProcessInterface::SystemProcesses();
 840   return NULL == _impl ? false : _impl->initialize();
 841 }
 842 
 843 SystemProcessInterface::~SystemProcessInterface() {
 844   if (_impl != NULL) {
 845     delete _impl;
 846   }
 847 }
 848 
 849 CPUInformationInterface::CPUInformationInterface() {
 850   _cpu_info = NULL;
 851 }
 852 
 853 bool CPUInformationInterface::initialize() {
 854   _cpu_info = new CPUInformation();
 855   if (NULL == _cpu_info) {
 856     return false;
 857   }
 858   _cpu_info->set_number_of_hardware_threads(VM_Version_Ext::number_of_threads());
 859   _cpu_info->set_number_of_cores(VM_Version_Ext::number_of_cores());
 860   _cpu_info->set_number_of_sockets(VM_Version_Ext::number_of_sockets());
 861   _cpu_info->set_cpu_name(VM_Version_Ext::cpu_name());
 862   _cpu_info->set_cpu_description(VM_Version_Ext::cpu_description());
 863 
 864   return true;
 865 }
 866 
 867 CPUInformationInterface::~CPUInformationInterface() {
 868   if (_cpu_info != NULL) {
 869     if (_cpu_info->cpu_name() != NULL) {
 870       const char* cpu_name = _cpu_info->cpu_name();
 871       FREE_C_HEAP_ARRAY(char, cpu_name);
 872       _cpu_info->set_cpu_name(NULL);
 873     }
 874     if (_cpu_info->cpu_description() != NULL) {
 875        const char* cpu_desc = _cpu_info->cpu_description();
 876        FREE_C_HEAP_ARRAY(char, cpu_desc);
 877       _cpu_info->set_cpu_description(NULL);
 878     }
 879     delete _cpu_info;
 880   }
 881 }
 882 
 883 int CPUInformationInterface::cpu_information(CPUInformation& cpu_info) {
 884   if (_cpu_info == NULL) {
 885     return OS_ERR;
 886   }
 887 
 888   cpu_info = *_cpu_info; // shallow copy assignment
 889   return OS_OK;
 890 }
 891 
 892 class NetworkPerformanceInterface::NetworkPerformance : public CHeapObj<mtInternal> {
 893   friend class NetworkPerformanceInterface;
 894  private:
 895   NetworkPerformance();
 896   NetworkPerformance(const NetworkPerformance& rhs); // no impl
 897   NetworkPerformance& operator=(const NetworkPerformance& rhs); // no impl
 898   bool initialize();
 899   ~NetworkPerformance();
 900   int network_utilization(NetworkInterface** network_interfaces) const;
 901 };
 902 
 903 NetworkPerformanceInterface::NetworkPerformance::NetworkPerformance() {
 904 
 905 }
 906 
 907 bool NetworkPerformanceInterface::NetworkPerformance::initialize() {
 908   return true;
 909 }
 910 
 911 NetworkPerformanceInterface::NetworkPerformance::~NetworkPerformance() {
 912 }
 913 
 914 int NetworkPerformanceInterface::NetworkPerformance::network_utilization(NetworkInterface** network_interfaces) const
 915 {
 916   return FUNCTIONALITY_NOT_IMPLEMENTED;
 917 }
 918 
 919 NetworkPerformanceInterface::NetworkPerformanceInterface() {
 920   _impl = NULL;
 921 }
 922 
 923 NetworkPerformanceInterface::~NetworkPerformanceInterface() {
 924   if (_impl != NULL) {
 925     delete _impl;
 926   }
 927 }
 928 
 929 bool NetworkPerformanceInterface::initialize() {
 930   _impl = new NetworkPerformanceInterface::NetworkPerformance();
 931   return _impl != NULL && _impl->initialize();
 932 }
 933 
 934 int NetworkPerformanceInterface::network_utilization(NetworkInterface** network_interfaces) const {
 935   return _impl->network_utilization(network_interfaces);
 936 }