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 "prims/unsafe.hpp"
  39 #include "runtime/arguments.hpp"
  40 #include "runtime/handles.inline.hpp"
  41 #include "runtime/javaCalls.hpp"
  42 #include "runtime/sharedRuntime.hpp"
  43 #include "runtime/signature.hpp"
  44 #include "utilities/macros.hpp"
  45 #if INCLUDE_TRACE
  46 #include "trace/traceMacros.hpp"
  47 #endif
  48 
  49 static void mangle_name_on(outputStream* st, Symbol* name, int begin, int end) {
  50   char* bytes = (char*)name->bytes() + begin;
  51   char* end_bytes = (char*)name->bytes() + end;
  52   while (bytes < end_bytes) {
  53     jchar c;
  54     bytes = UTF8::next(bytes, &c);
  55     if (c <= 0x7f && isalnum(c)) {
  56       st->put((char) c);
  57     } else {
  58            if (c == '_') st->print("_1");
  59       else if (c == '/') st->print("_");
  60       else if (c == ';') st->print("_2");
  61       else if (c == '[') st->print("_3");
  62       else               st->print("_%.5x", c);
  63     }
  64   }
  65 }
  66 
  67 
  68 static void mangle_name_on(outputStream* st, Symbol* name) {
  69   mangle_name_on(st, name, 0, name->utf8_length());
  70 }
  71 
  72 
  73 char* NativeLookup::pure_jni_name(const methodHandle& method) {
  74   stringStream st;
  75   // Prefix
  76   st.print("Java_");
  77   // Klass name
  78   mangle_name_on(&st, method->klass_name());
  79   st.print("_");
  80   // Method name
  81   mangle_name_on(&st, method->name());
  82   return st.as_string();
  83 }
  84 
  85 
  86 char* NativeLookup::critical_jni_name(const methodHandle& method) {
  87   stringStream st;
  88   // Prefix
  89   st.print("JavaCritical_");
  90   // Klass name
  91   mangle_name_on(&st, method->klass_name());
  92   st.print("_");
  93   // Method name
  94   mangle_name_on(&st, method->name());
  95   return st.as_string();
  96 }
  97 
  98 
  99 char* NativeLookup::long_jni_name(const methodHandle& method) {
 100   // Signature ignore the wrapping parenteses and the trailing return type
 101   stringStream st;
 102   Symbol* signature = method->signature();
 103   st.print("__");
 104   // find ')'
 105   int end;
 106   for (end = 0; end < signature->utf8_length() && signature->byte_at(end) != ')'; end++);
 107   // skip first '('
 108   mangle_name_on(&st, signature, 1, end);
 109   return st.as_string();
 110 }
 111 
 112 extern "C" {
 113   void JNICALL JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass unsafecls);
 114   void JNICALL JVM_RegisterPerfMethods(JNIEnv *env, jclass perfclass);
 115   void JNICALL JVM_RegisterWhiteBoxMethods(JNIEnv *env, jclass wbclass);

 116 #if INCLUDE_JVMCI
 117   jobject  JNICALL JVM_GetJVMCIRuntime(JNIEnv *env, jclass c);
 118   void     JNICALL JVM_RegisterJVMCINatives(JNIEnv *env, jclass compilerToVMClass);
 119 #endif
 120 }
 121 
 122 #define CC (char*)  /* cast a literal from (const char*) */
 123 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
 124 
 125 static JNINativeMethod lookup_special_native_methods[] = {
 126   { CC"Java_jdk_internal_misc_Unsafe_registerNatives",             NULL, FN_PTR(JVM_RegisterJDKInternalMiscUnsafeMethods) },
 127   { CC"Java_java_lang_invoke_MethodHandleNatives_registerNatives", NULL, FN_PTR(JVM_RegisterMethodHandleMethods) },
 128   { CC"Java_jdk_internal_perf_Perf_registerNatives",               NULL, FN_PTR(JVM_RegisterPerfMethods)         },
 129   { CC"Java_sun_hotspot_WhiteBox_registerNatives",                 NULL, FN_PTR(JVM_RegisterWhiteBoxMethods)     },

 130 #if INCLUDE_JVMCI
 131   { CC"Java_jdk_vm_ci_runtime_JVMCI_initializeRuntime",            NULL, FN_PTR(JVM_GetJVMCIRuntime)             },
 132   { CC"Java_jdk_vm_ci_hotspot_CompilerToVM_registerNatives",       NULL, FN_PTR(JVM_RegisterJVMCINatives)        },
 133 #endif
 134 #if INCLUDE_TRACE
 135   { CC"Java_jdk_jfr_internal_JVM_registerNatives",                 NULL, TRACE_REGISTER_NATIVES                  },
 136 #endif
 137 };
 138 
 139 static address lookup_special_native(char* jni_name) {
 140   int count = sizeof(lookup_special_native_methods) / sizeof(JNINativeMethod);
 141   for (int i = 0; i < count; i++) {
 142     // NB: To ignore the jni prefix and jni postfix strstr is used matching.
 143     if (strstr(jni_name, lookup_special_native_methods[i].name) != NULL) {
 144       return CAST_FROM_FN_PTR(address, lookup_special_native_methods[i].fnPtr);
 145     }
 146   }
 147   return NULL;
 148 }
 149 
 150 address NativeLookup::lookup_style(const methodHandle& method, char* pure_name, const char* long_name, int args_size, bool os_style, bool& in_base_library, TRAPS) {
 151   address entry;
 152   // Compute complete JNI name for style
 153   stringStream st;
 154   if (os_style) os::print_jni_name_prefix_on(&st, args_size);
 155   st.print_raw(pure_name);
 156   st.print_raw(long_name);
 157   if (os_style) os::print_jni_name_suffix_on(&st, args_size);
 158   char* jni_name = st.as_string();
 159 
 160   // If the loader is null we have a system class, so we attempt a lookup in
 161   // the native Java library. This takes care of any bootstrapping problems.
 162   // Note: It is critical for bootstrapping that Java_java_lang_ClassLoader_00024NativeLibrary_find
 163   // gets found the first time around - otherwise an infinite loop can occure. This is
 164   // another VM/library dependency
 165   Handle loader(THREAD, method->method_holder()->class_loader());
 166   if (loader.is_null()) {
 167     entry = lookup_special_native(jni_name);
 168     if (entry == NULL) {
 169        entry = (address) os::dll_lookup(os::native_java_library(), jni_name);
 170     }
 171     if (entry != NULL) {
 172       in_base_library = true;
 173       return entry;
 174     }
 175   }
 176 
 177   // Otherwise call static method findNative in ClassLoader
 178   Klass*   klass = SystemDictionary::ClassLoader_klass();
 179   Handle name_arg = java_lang_String::create_from_str(jni_name, CHECK_NULL);
 180 
 181   JavaValue result(T_LONG);
 182   JavaCalls::call_static(&result,
 183                          klass,
 184                          vmSymbols::findNative_name(),
 185                          vmSymbols::classloader_string_long_signature(),
 186                          // Arguments
 187                          loader,
 188                          name_arg,
 189                          CHECK_NULL);
 190   entry = (address) (intptr_t) result.get_jlong();
 191 
 192   if (entry == NULL) {
 193     // findNative didn't find it, if there are any agent libraries look in them
 194     AgentLibrary* agent;
 195     for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
 196       entry = (address) os::dll_lookup(agent->os_lib(), jni_name);
 197       if (entry != NULL) {
 198         return entry;
 199       }
 200     }
 201   }
 202 
 203   return entry;
 204 }
 205 
 206 
 207 address NativeLookup::lookup_critical_style(const methodHandle& method, char* pure_name, const char* long_name, int args_size, bool os_style) {
 208   if (!method->has_native_function()) {
 209     return NULL;
 210   }
 211 
 212   address current_entry = method->native_function();
 213 
 214   char dll_name[JVM_MAXPATHLEN];
 215   int offset;
 216   if (os::dll_address_to_library_name(current_entry, dll_name, sizeof(dll_name), &offset)) {
 217     char ebuf[32];
 218     void* dll = os::dll_load(dll_name, ebuf, sizeof(ebuf));
 219     if (dll != NULL) {
 220       // Compute complete JNI name for style
 221       stringStream st;
 222       if (os_style) os::print_jni_name_prefix_on(&st, args_size);
 223       st.print_raw(pure_name);
 224       st.print_raw(long_name);
 225       if (os_style) os::print_jni_name_suffix_on(&st, args_size);
 226       char* jni_name = st.as_string();
 227       return (address)os::dll_lookup(dll, jni_name);
 228     }
 229   }
 230 
 231   return NULL;
 232 }
 233 
 234 
 235 // Check all the formats of native implementation name to see if there is one
 236 // for the specified method.
 237 address NativeLookup::lookup_entry(const methodHandle& method, bool& in_base_library, TRAPS) {
 238   address entry = NULL;
 239   in_base_library = false;
 240   // Compute pure name
 241   char* pure_name = pure_jni_name(method);
 242 
 243   // Compute argument size
 244   int args_size = 1                             // JNIEnv
 245                 + (method->is_static() ? 1 : 0) // class for static methods
 246                 + method->size_of_parameters(); // actual parameters
 247 
 248 
 249   // 1) Try JNI short style
 250   entry = lookup_style(method, pure_name, "",        args_size, true,  in_base_library, CHECK_NULL);
 251   if (entry != NULL) return entry;
 252 
 253   // Compute long name
 254   char* long_name = long_jni_name(method);
 255 
 256   // 2) Try JNI long style
 257   entry = lookup_style(method, pure_name, long_name, args_size, true,  in_base_library, CHECK_NULL);
 258   if (entry != NULL) return entry;
 259 
 260   // 3) Try JNI short style without os prefix/suffix
 261   entry = lookup_style(method, pure_name, "",        args_size, false, in_base_library, CHECK_NULL);
 262   if (entry != NULL) return entry;
 263 
 264   // 4) Try JNI long style without os prefix/suffix
 265   entry = lookup_style(method, pure_name, long_name, args_size, false, in_base_library, CHECK_NULL);
 266 
 267   return entry; // NULL indicates not found
 268 }
 269 
 270 // Check all the formats of native implementation name to see if there is one
 271 // for the specified method.
 272 address NativeLookup::lookup_critical_entry(const methodHandle& method) {
 273   if (!CriticalJNINatives) return NULL;
 274 
 275   if (method->is_synchronized() ||
 276       !method->is_static()) {
 277     // Only static non-synchronized methods are allowed
 278     return NULL;
 279   }
 280 
 281   ResourceMark rm;
 282   address entry = NULL;
 283 
 284   Symbol* signature = method->signature();
 285   for (int end = 0; end < signature->utf8_length(); end++) {
 286     if (signature->byte_at(end) == 'L') {
 287       // Don't allow object types
 288       return NULL;
 289     }
 290   }
 291 
 292   // Compute critical name
 293   char* critical_name = critical_jni_name(method);
 294 
 295   // Compute argument size
 296   int args_size = 1                             // JNIEnv
 297                 + (method->is_static() ? 1 : 0) // class for static methods
 298                 + method->size_of_parameters(); // actual parameters
 299 
 300 
 301   // 1) Try JNI short style
 302   entry = lookup_critical_style(method, critical_name, "",        args_size, true);
 303   if (entry != NULL) return entry;
 304 
 305   // Compute long name
 306   char* long_name = long_jni_name(method);
 307 
 308   // 2) Try JNI long style
 309   entry = lookup_critical_style(method, critical_name, long_name, args_size, true);
 310   if (entry != NULL) return entry;
 311 
 312   // 3) Try JNI short style without os prefix/suffix
 313   entry = lookup_critical_style(method, critical_name, "",        args_size, false);
 314   if (entry != NULL) return entry;
 315 
 316   // 4) Try JNI long style without os prefix/suffix
 317   entry = lookup_critical_style(method, critical_name, long_name, args_size, false);
 318 
 319   return entry; // NULL indicates not found
 320 }
 321 
 322 // Check if there are any JVM TI prefixes which have been applied to the native method name.
 323 // If any are found, remove them before attemping the look up of the
 324 // native implementation again.
 325 // See SetNativeMethodPrefix in the JVM TI Spec for more details.
 326 address NativeLookup::lookup_entry_prefixed(const methodHandle& method, bool& in_base_library, TRAPS) {
 327 #if INCLUDE_JVMTI
 328   ResourceMark rm(THREAD);
 329 
 330   int prefix_count;
 331   char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
 332   char* in_name = method->name()->as_C_string();
 333   char* wrapper_name = in_name;
 334   // last applied prefix will be first -- go backwards
 335   for (int i = prefix_count-1; i >= 0; i--) {
 336     char* prefix = prefixes[i];
 337     size_t prefix_len = strlen(prefix);
 338     if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
 339       // has this prefix remove it
 340       wrapper_name += prefix_len;
 341     }
 342   }
 343   if (wrapper_name != in_name) {
 344     // we have a name for a wrapping method
 345     int wrapper_name_len = (int)strlen(wrapper_name);
 346     TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);
 347     if (wrapper_symbol != NULL) {
 348       Klass* k = method->method_holder();
 349       Method* wrapper_method = k->lookup_method(wrapper_symbol, method->signature());
 350       if (wrapper_method != NULL && !wrapper_method->is_native()) {
 351         // we found a wrapper method, use its native entry
 352         method->set_is_prefixed_native();
 353         return lookup_entry(wrapper_method, in_base_library, THREAD);
 354       }
 355     }
 356   }
 357 #endif // INCLUDE_JVMTI
 358   return NULL;
 359 }
 360 
 361 address NativeLookup::lookup_base(const methodHandle& method, bool& in_base_library, TRAPS) {
 362   address entry = NULL;
 363   ResourceMark rm(THREAD);
 364 
 365   entry = lookup_entry(method, in_base_library, THREAD);
 366   if (entry != NULL) return entry;
 367 
 368   // standard native method resolution has failed.  Check if there are any
 369   // JVM TI prefixes which have been applied to the native method name.
 370   entry = lookup_entry_prefixed(method, in_base_library, THREAD);
 371   if (entry != NULL) return entry;
 372 
 373   // Native function not found, throw UnsatisfiedLinkError
 374   THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(),
 375               method->name_and_sig_as_C_string());
 376 }
 377 
 378 
 379 address NativeLookup::lookup(const methodHandle& method, bool& in_base_library, TRAPS) {
 380   if (!method->has_native_function()) {
 381     address entry = lookup_base(method, in_base_library, CHECK_NULL);
 382     method->set_native_function(entry,
 383       Method::native_bind_event_is_interesting);
 384     // -verbose:jni printing
 385     if (PrintJNIResolving) {
 386       ResourceMark rm(THREAD);
 387       tty->print_cr("[Dynamic-linking native method %s.%s ... JNI]",
 388         method->method_holder()->external_name(),
 389         method->name()->as_C_string());
 390     }
 391   }
 392   return method->native_function();
 393 }
 394 
 395 address NativeLookup::base_library_lookup(const char* class_name, const char* method_name, const char* signature) {
 396   EXCEPTION_MARK;
 397   bool in_base_library = true;  // SharedRuntime inits some math methods.
 398   TempNewSymbol c_name = SymbolTable::new_symbol(class_name,  CATCH);
 399   TempNewSymbol m_name = SymbolTable::new_symbol(method_name, CATCH);
 400   TempNewSymbol s_name = SymbolTable::new_symbol(signature,   CATCH);
 401 
 402   // Find the class
 403   Klass* k = SystemDictionary::resolve_or_fail(c_name, true, CATCH);
 404   InstanceKlass* klass  = InstanceKlass::cast(k);
 405 
 406   // Find method and invoke standard lookup
 407   methodHandle method (THREAD,
 408                        klass->uncached_lookup_method(m_name, s_name, Klass::find_overpass));
 409   address result = lookup(method, in_base_library, CATCH);
 410   assert(in_base_library, "must be in basic library");
 411   guarantee(result != NULL, "must be non NULL");
 412   return result;
 413 }
--- EOF ---