1 /*
   2  * Copyright (c) 1997, 2017, 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 "classfile/javaClasses.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "classfile/vmSymbols.hpp"
  29 #include "memory/oopFactory.hpp"
  30 #include "memory/resourceArea.hpp"
  31 #include "memory/universe.inline.hpp"
  32 #include "oops/instanceKlass.hpp"
  33 #include "oops/method.hpp"
  34 #include "oops/oop.inline.hpp"
  35 #include "oops/symbol.hpp"
  36 #include "prims/jvm_misc.hpp"
  37 #include "prims/nativeLookup.hpp"
  38 #include "runtime/arguments.hpp"
  39 #include "runtime/handles.inline.hpp"
  40 #include "runtime/javaCalls.hpp"
  41 #include "runtime/sharedRuntime.hpp"
  42 #include "runtime/signature.hpp"
  43 #include "utilities/macros.hpp"
  44 #if INCLUDE_JFR
  45 #include "jfr/jfr.hpp"
  46 #endif
  47 #ifdef TARGET_OS_FAMILY_linux
  48 # include "os_linux.inline.hpp"
  49 #endif
  50 #ifdef TARGET_OS_FAMILY_solaris
  51 # include "os_solaris.inline.hpp"
  52 #endif
  53 #ifdef TARGET_OS_FAMILY_windows
  54 # include "os_windows.inline.hpp"
  55 #endif
  56 #ifdef TARGET_OS_FAMILY_aix
  57 # include "os_aix.inline.hpp"
  58 #endif
  59 #ifdef TARGET_OS_FAMILY_bsd
  60 # include "os_bsd.inline.hpp"
  61 #endif
  62 
  63 
  64 static void mangle_name_on(outputStream* st, Symbol* name, int begin, int end) {
  65   char* bytes = (char*)name->bytes() + begin;
  66   char* end_bytes = (char*)name->bytes() + end;
  67   while (bytes < end_bytes) {
  68     jchar c;
  69     bytes = UTF8::next(bytes, &c);
  70     if (c <= 0x7f && isalnum(c)) {
  71       st->put((char) c);
  72     } else {
  73            if (c == '_') st->print("_1");
  74       else if (c == '/') st->print("_");
  75       else if (c == ';') st->print("_2");
  76       else if (c == '[') st->print("_3");
  77       else               st->print("_%.5x", c);
  78     }
  79   }
  80 }
  81 
  82 
  83 static void mangle_name_on(outputStream* st, Symbol* name) {
  84   mangle_name_on(st, name, 0, name->utf8_length());
  85 }
  86 
  87 
  88 char* NativeLookup::pure_jni_name(methodHandle method) {
  89   stringStream st;
  90   // Prefix
  91   st.print("Java_");
  92   // Klass name
  93   mangle_name_on(&st, method->klass_name());
  94   st.print("_");
  95   // Method name
  96   mangle_name_on(&st, method->name());
  97   return st.as_string();
  98 }
  99 
 100 
 101 char* NativeLookup::critical_jni_name(methodHandle method) {
 102   stringStream st;
 103   // Prefix
 104   st.print("JavaCritical_");
 105   // Klass name
 106   mangle_name_on(&st, method->klass_name());
 107   st.print("_");
 108   // Method name
 109   mangle_name_on(&st, method->name());
 110   return st.as_string();
 111 }
 112 
 113 
 114 char* NativeLookup::long_jni_name(methodHandle method) {
 115   // Signature ignore the wrapping parenteses and the trailing return type
 116   stringStream st;
 117   Symbol* signature = method->signature();
 118   st.print("__");
 119   // find ')'
 120   int end;
 121   for (end = 0; end < signature->utf8_length() && signature->byte_at(end) != ')'; end++);
 122   // skip first '('
 123   mangle_name_on(&st, signature, 1, end);
 124   return st.as_string();
 125 }
 126 
 127 extern "C" {
 128   void JNICALL JVM_RegisterUnsafeMethods(JNIEnv *env, jclass unsafecls);
 129   void JNICALL JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass unsafecls);
 130   void JNICALL JVM_RegisterPerfMethods(JNIEnv *env, jclass perfclass);
 131   void JNICALL JVM_RegisterWhiteBoxMethods(JNIEnv *env, jclass wbclass);
 132 }
 133 
 134 #define CC (char*)  /* cast a literal from (const char*) */
 135 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
 136 
 137 static JNINativeMethod lookup_special_native_methods[] = {
 138   { CC"Java_sun_misc_Unsafe_registerNatives",                      NULL, FN_PTR(JVM_RegisterUnsafeMethods)       },
 139   { CC"Java_java_lang_invoke_MethodHandleNatives_registerNatives", NULL, FN_PTR(JVM_RegisterMethodHandleMethods) },
 140   { CC"Java_sun_misc_Perf_registerNatives",                        NULL, FN_PTR(JVM_RegisterPerfMethods)         },
 141   { CC"Java_sun_hotspot_WhiteBox_registerNatives",                 NULL, FN_PTR(JVM_RegisterWhiteBoxMethods)     },
 142 #if INCLUDE_JFR
 143   { CC"Java_jdk_jfr_internal_JVM_registerNatives",                 NULL, FN_PTR(jfr_register_natives)            },
 144 #endif
 145 };
 146 
 147 static address lookup_special_native(char* jni_name) {
 148   int count = sizeof(lookup_special_native_methods) / sizeof(JNINativeMethod);
 149   for (int i = 0; i < count; i++) {
 150     // NB: To ignore the jni prefix and jni postfix strstr is used matching.
 151     if (strstr(jni_name, lookup_special_native_methods[i].name) != NULL) {
 152       return CAST_FROM_FN_PTR(address, lookup_special_native_methods[i].fnPtr);
 153     }
 154   }
 155   return NULL;
 156 }
 157 
 158 address NativeLookup::lookup_style(methodHandle method, char* pure_name, const char* long_name, int args_size, bool os_style, bool& in_base_library, TRAPS) {
 159   address entry;
 160   // Compute complete JNI name for style
 161   stringStream st;
 162   if (os_style) os::print_jni_name_prefix_on(&st, args_size);
 163   st.print_raw(pure_name);
 164   st.print_raw(long_name);
 165   if (os_style) os::print_jni_name_suffix_on(&st, args_size);
 166   char* jni_name = st.as_string();
 167 
 168   // If the loader is null we have a system class, so we attempt a lookup in
 169   // the native Java library. This takes care of any bootstrapping problems.
 170   // Note: It is critical for bootstrapping that Java_java_lang_ClassLoader_00024NativeLibrary_find
 171   // gets found the first time around - otherwise an infinite loop can occure. This is
 172   // another VM/library dependency
 173   Handle loader(THREAD, method->method_holder()->class_loader());
 174   if (loader.is_null()) {
 175     entry = lookup_special_native(jni_name);
 176     if (entry == NULL) {
 177        entry = (address) os::dll_lookup(os::native_java_library(), jni_name);
 178     }
 179     if (entry != NULL) {
 180       in_base_library = true;
 181       return entry;
 182     }
 183   }
 184 
 185   // Otherwise call static method findNative in ClassLoader
 186   KlassHandle   klass (THREAD, SystemDictionary::ClassLoader_klass());
 187   Handle name_arg = java_lang_String::create_from_str(jni_name, CHECK_NULL);
 188 
 189   JavaValue result(T_LONG);
 190   JavaCalls::call_static(&result,
 191                          klass,
 192                          vmSymbols::findNative_name(),
 193                          vmSymbols::classloader_string_long_signature(),
 194                          // Arguments
 195                          loader,
 196                          name_arg,
 197                          CHECK_NULL);
 198   entry = (address) (intptr_t) result.get_jlong();
 199 
 200   if (entry == NULL) {
 201     // findNative didn't find it, if there are any agent libraries look in them
 202     AgentLibrary* agent;
 203     for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
 204       entry = (address) os::dll_lookup(agent->os_lib(), jni_name);
 205       if (entry != NULL) {
 206         return entry;
 207       }
 208     }
 209   }
 210 
 211   return entry;
 212 }
 213 
 214 
 215 address NativeLookup::lookup_critical_style(methodHandle method, char* pure_name, const char* long_name, int args_size, bool os_style) {
 216   if (!method->has_native_function()) {
 217     return NULL;
 218   }
 219 
 220   address current_entry = method->native_function();
 221 
 222   char dll_name[JVM_MAXPATHLEN];
 223   int offset;
 224   if (os::dll_address_to_library_name(current_entry, dll_name, sizeof(dll_name), &offset)) {
 225     char ebuf[32];
 226     void* dll = os::dll_load(dll_name, ebuf, sizeof(ebuf));
 227     if (dll != NULL) {
 228       // Compute complete JNI name for style
 229       stringStream st;
 230       if (os_style) os::print_jni_name_prefix_on(&st, args_size);
 231       st.print_raw(pure_name);
 232       st.print_raw(long_name);
 233       if (os_style) os::print_jni_name_suffix_on(&st, args_size);
 234       char* jni_name = st.as_string();
 235       return (address)os::dll_lookup(dll, jni_name);
 236     }
 237   }
 238 
 239   return NULL;
 240 }
 241 
 242 
 243 // Check all the formats of native implementation name to see if there is one
 244 // for the specified method.
 245 address NativeLookup::lookup_entry(methodHandle method, bool& in_base_library, TRAPS) {
 246   address entry = NULL;
 247   in_base_library = false;
 248   // Compute pure name
 249   char* pure_name = pure_jni_name(method);
 250 
 251   // Compute argument size
 252   int args_size = 1                             // JNIEnv
 253                 + (method->is_static() ? 1 : 0) // class for static methods
 254                 + method->size_of_parameters(); // actual parameters
 255 
 256 
 257   // 1) Try JNI short style
 258   entry = lookup_style(method, pure_name, "",        args_size, true,  in_base_library, CHECK_NULL);
 259   if (entry != NULL) return entry;
 260 
 261   // Compute long name
 262   char* long_name = long_jni_name(method);
 263 
 264   // 2) Try JNI long style
 265   entry = lookup_style(method, pure_name, long_name, args_size, true,  in_base_library, CHECK_NULL);
 266   if (entry != NULL) return entry;
 267 
 268   // 3) Try JNI short style without os prefix/suffix
 269   entry = lookup_style(method, pure_name, "",        args_size, false, in_base_library, CHECK_NULL);
 270   if (entry != NULL) return entry;
 271 
 272   // 4) Try JNI long style without os prefix/suffix
 273   entry = lookup_style(method, pure_name, long_name, args_size, false, in_base_library, CHECK_NULL);
 274 
 275   return entry; // NULL indicates not found
 276 }
 277 
 278 // Check all the formats of native implementation name to see if there is one
 279 // for the specified method.
 280 address NativeLookup::lookup_critical_entry(methodHandle method) {
 281   if (!CriticalJNINatives) return NULL;
 282 
 283   if (method->is_synchronized() ||
 284       !method->is_static()) {
 285     // Only static non-synchronized methods are allowed
 286     return NULL;
 287   }
 288 
 289   ResourceMark rm;
 290   address entry = NULL;
 291 
 292   Symbol* signature = method->signature();
 293   for (int end = 0; end < signature->utf8_length(); end++) {
 294     if (signature->byte_at(end) == 'L') {
 295       // Don't allow object types
 296       return NULL;
 297     }
 298   }
 299 
 300   // Compute critical name
 301   char* critical_name = critical_jni_name(method);
 302 
 303   // Compute argument size
 304   int args_size = 1                             // JNIEnv
 305                 + (method->is_static() ? 1 : 0) // class for static methods
 306                 + method->size_of_parameters(); // actual parameters
 307 
 308 
 309   // 1) Try JNI short style
 310   entry = lookup_critical_style(method, critical_name, "",        args_size, true);
 311   if (entry != NULL) return entry;
 312 
 313   // Compute long name
 314   char* long_name = long_jni_name(method);
 315 
 316   // 2) Try JNI long style
 317   entry = lookup_critical_style(method, critical_name, long_name, args_size, true);
 318   if (entry != NULL) return entry;
 319 
 320   // 3) Try JNI short style without os prefix/suffix
 321   entry = lookup_critical_style(method, critical_name, "",        args_size, false);
 322   if (entry != NULL) return entry;
 323 
 324   // 4) Try JNI long style without os prefix/suffix
 325   entry = lookup_critical_style(method, critical_name, long_name, args_size, false);
 326 
 327   return entry; // NULL indicates not found
 328 }
 329 
 330 // Check if there are any JVM TI prefixes which have been applied to the native method name.
 331 // If any are found, remove them before attemping the look up of the
 332 // native implementation again.
 333 // See SetNativeMethodPrefix in the JVM TI Spec for more details.
 334 address NativeLookup::lookup_entry_prefixed(methodHandle method, bool& in_base_library, TRAPS) {
 335 #if INCLUDE_JVMTI
 336   ResourceMark rm(THREAD);
 337 
 338   int prefix_count;
 339   char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
 340   char* in_name = method->name()->as_C_string();
 341   char* wrapper_name = in_name;
 342   // last applied prefix will be first -- go backwards
 343   for (int i = prefix_count-1; i >= 0; i--) {
 344     char* prefix = prefixes[i];
 345     size_t prefix_len = strlen(prefix);
 346     if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
 347       // has this prefix remove it
 348       wrapper_name += prefix_len;
 349     }
 350   }
 351   if (wrapper_name != in_name) {
 352     // we have a name for a wrapping method
 353     int wrapper_name_len = (int)strlen(wrapper_name);
 354     TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);
 355     if (wrapper_symbol != NULL) {
 356       KlassHandle kh(method->method_holder());
 357       Method* wrapper_method = kh()->lookup_method(wrapper_symbol,
 358                                                                   method->signature());
 359       if (wrapper_method != NULL && !wrapper_method->is_native()) {
 360         // we found a wrapper method, use its native entry
 361         method->set_is_prefixed_native();
 362         return lookup_entry(wrapper_method, in_base_library, THREAD);
 363       }
 364     }
 365   }
 366 #endif // INCLUDE_JVMTI
 367   return NULL;
 368 }
 369 
 370 address NativeLookup::lookup_base(methodHandle method, bool& in_base_library, TRAPS) {
 371   address entry = NULL;
 372   ResourceMark rm(THREAD);
 373 
 374   entry = lookup_entry(method, in_base_library, THREAD);
 375   if (entry != NULL) return entry;
 376 
 377   // standard native method resolution has failed.  Check if there are any
 378   // JVM TI prefixes which have been applied to the native method name.
 379   entry = lookup_entry_prefixed(method, in_base_library, THREAD);
 380   if (entry != NULL) return entry;
 381 
 382   // Native function not found, throw UnsatisfiedLinkError
 383   THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(),
 384               method->name_and_sig_as_C_string());
 385 }
 386 
 387 
 388 address NativeLookup::lookup(methodHandle method, bool& in_base_library, TRAPS) {
 389   if (!method->has_native_function()) {
 390     address entry = lookup_base(method, in_base_library, CHECK_NULL);
 391     method->set_native_function(entry,
 392       Method::native_bind_event_is_interesting);
 393     // -verbose:jni printing
 394     if (PrintJNIResolving) {
 395       ResourceMark rm(THREAD);
 396       tty->print_cr("[Dynamic-linking native method %s.%s ... JNI]",
 397         method->method_holder()->external_name(),
 398         method->name()->as_C_string());
 399     }
 400   }
 401   return method->native_function();
 402 }
 403 
 404 address NativeLookup::base_library_lookup(const char* class_name, const char* method_name, const char* signature) {
 405   EXCEPTION_MARK;
 406   bool in_base_library = true;  // SharedRuntime inits some math methods.
 407   TempNewSymbol c_name = SymbolTable::new_symbol(class_name,  CATCH);
 408   TempNewSymbol m_name = SymbolTable::new_symbol(method_name, CATCH);
 409   TempNewSymbol s_name = SymbolTable::new_symbol(signature,   CATCH);
 410 
 411   // Find the class
 412   Klass* k = SystemDictionary::resolve_or_fail(c_name, true, CATCH);
 413   instanceKlassHandle klass (THREAD, k);
 414 
 415   // Find method and invoke standard lookup
 416   methodHandle method (THREAD,
 417                        klass->uncached_lookup_method(m_name, s_name, Klass::find_overpass));
 418   address result = lookup(method, in_base_library, CATCH);
 419   assert(in_base_library, "must be in basic library");
 420   guarantee(result != NULL, "must be non NULL");
 421   return result;
 422 }
--- EOF ---