1 /*
   2  * Copyright (c) 1997, 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 "classfile/javaClasses.hpp"
  27 #include "classfile/symbolTable.hpp"
  28 #include "classfile/systemDictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "memory/oopFactory.hpp"
  31 #include "memory/resourceArea.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/os.inline.hpp"
  43 #include "runtime/sharedRuntime.hpp"
  44 #include "runtime/signature.hpp"
  45 #include "utilities/macros.hpp"
  46 #include "utilities/utf8.hpp"
  47 #if INCLUDE_JFR
  48 #include "jfr/jfr.hpp"
  49 #endif
  50 
  51 static void mangle_name_on(outputStream* st, Symbol* name, int begin, int end) {
  52   char* bytes = (char*)name->bytes() + begin;
  53   char* end_bytes = (char*)name->bytes() + end;
  54   while (bytes < end_bytes) {
  55     jchar c;
  56     bytes = UTF8::next(bytes, &c);
  57     if (c <= 0x7f && isalnum(c)) {
  58       st->put((char) c);
  59     } else {
  60            if (c == '_') st->print("_1");
  61       else if (c == '/') st->print("_");
  62       else if (c == ';') st->print("_2");
  63       else if (c == '[') st->print("_3");
  64       else               st->print("_%.5x", c);
  65     }
  66   }
  67 }
  68 
  69 
  70 static void mangle_name_on(outputStream* st, Symbol* name) {
  71   mangle_name_on(st, name, 0, name->utf8_length());
  72 }
  73 
  74 
  75 char* NativeLookup::pure_jni_name(const methodHandle& method) {
  76   stringStream st;
  77   // Prefix
  78   st.print("Java_");
  79   // Klass name
  80   mangle_name_on(&st, method->klass_name());
  81   st.print("_");
  82   // Method name
  83   mangle_name_on(&st, method->name());
  84   return st.as_string();
  85 }
  86 
  87 
  88 char* NativeLookup::critical_jni_name(const methodHandle& method) {
  89   stringStream st;
  90   // Prefix
  91   st.print("JavaCritical_");
  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::long_jni_name(const methodHandle& method) {
 102   // Signature ignore the wrapping parenteses and the trailing return type
 103   stringStream st;
 104   Symbol* signature = method->signature();
 105   st.print("__");
 106   // find ')'
 107   int end;
 108   for (end = 0; end < signature->utf8_length() && signature->char_at(end) != ')'; end++);
 109   // skip first '('
 110   mangle_name_on(&st, signature, 1, end);
 111   return st.as_string();
 112 }
 113 
 114 extern "C" {
 115   void JNICALL JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass unsafecls);
 116   void JNICALL JVM_RegisterPerfMethods(JNIEnv *env, jclass perfclass);
 117   void JNICALL JVM_RegisterWhiteBoxMethods(JNIEnv *env, jclass wbclass);
 118 #if INCLUDE_JVMCI
 119   jobject  JNICALL JVM_GetJVMCIRuntime(JNIEnv *env, jclass c);
 120   void     JNICALL JVM_RegisterJVMCINatives(JNIEnv *env, jclass compilerToVMClass);
 121 #endif
 122 }
 123 
 124 #define CC (char*)  /* cast a literal from (const char*) */
 125 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
 126 
 127 static JNINativeMethod lookup_special_native_methods[] = {
 128   { CC"Java_jdk_internal_misc_Unsafe_registerNatives",             NULL, FN_PTR(JVM_RegisterJDKInternalMiscUnsafeMethods) },
 129   { CC"Java_java_lang_invoke_MethodHandleNatives_registerNatives", NULL, FN_PTR(JVM_RegisterMethodHandleMethods) },
 130   { CC"Java_jdk_internal_perf_Perf_registerNatives",               NULL, FN_PTR(JVM_RegisterPerfMethods)         },
 131   { CC"Java_sun_hotspot_WhiteBox_registerNatives",                 NULL, FN_PTR(JVM_RegisterWhiteBoxMethods)     },
 132 #if INCLUDE_JVMCI
 133   { CC"Java_jdk_vm_ci_runtime_JVMCI_initializeRuntime",            NULL, FN_PTR(JVM_GetJVMCIRuntime)             },
 134   { CC"Java_jdk_vm_ci_hotspot_CompilerToVM_registerNatives",       NULL, FN_PTR(JVM_RegisterJVMCINatives)        },
 135 #endif
 136 #if INCLUDE_JFR
 137   { CC"Java_jdk_jfr_internal_JVM_registerNatives",                 NULL, FN_PTR(jfr_register_natives)            },
 138 #endif
 139 };
 140 
 141 static address lookup_special_native(char* jni_name) {
 142   int count = sizeof(lookup_special_native_methods) / sizeof(JNINativeMethod);
 143   for (int i = 0; i < count; i++) {
 144     // NB: To ignore the jni prefix and jni postfix strstr is used matching.
 145     if (strstr(jni_name, lookup_special_native_methods[i].name) != NULL) {
 146       return CAST_FROM_FN_PTR(address, lookup_special_native_methods[i].fnPtr);
 147     }
 148   }
 149   return NULL;
 150 }
 151 
 152 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) {
 153   address entry;
 154   // Compute complete JNI name for style
 155   stringStream st;
 156   if (os_style) os::print_jni_name_prefix_on(&st, args_size);
 157   st.print_raw(pure_name);
 158   st.print_raw(long_name);
 159   if (os_style) os::print_jni_name_suffix_on(&st, args_size);
 160   char* jni_name = st.as_string();
 161 
 162   // If the loader is null we have a system class, so we attempt a lookup in
 163   // the native Java library. This takes care of any bootstrapping problems.
 164   // Note: It is critical for bootstrapping that Java_java_lang_ClassLoader_00024NativeLibrary_find
 165   // gets found the first time around - otherwise an infinite loop can occure. This is
 166   // another VM/library dependency
 167   Handle loader(THREAD, method->method_holder()->class_loader());
 168   if (loader.is_null()) {
 169     entry = lookup_special_native(jni_name);
 170     if (entry == NULL) {
 171        entry = (address) os::dll_lookup(os::native_java_library(), jni_name);
 172     }
 173     if (entry != NULL) {
 174       in_base_library = true;
 175       return entry;
 176     }
 177   }
 178 
 179   // Otherwise call static method findNative in ClassLoader
 180   Klass*   klass = SystemDictionary::ClassLoader_klass();
 181   Handle name_arg = java_lang_String::create_from_str(jni_name, CHECK_NULL);
 182 
 183   JavaValue result(T_LONG);
 184   JavaCalls::call_static(&result,
 185                          klass,
 186                          vmSymbols::findNative_name(),
 187                          vmSymbols::classloader_string_long_signature(),
 188                          // Arguments
 189                          loader,
 190                          name_arg,
 191                          CHECK_NULL);
 192   entry = (address) (intptr_t) result.get_jlong();
 193 
 194   if (entry == NULL) {
 195     // findNative didn't find it, if there are any agent libraries look in them
 196     AgentLibrary* agent;
 197     for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
 198       entry = (address) os::dll_lookup(agent->os_lib(), jni_name);
 199       if (entry != NULL) {
 200         return entry;
 201       }
 202     }
 203   }
 204 
 205   return entry;
 206 }
 207 
 208 
 209 address NativeLookup::lookup_critical_style(const methodHandle& method, char* pure_name, const char* long_name, int args_size, bool os_style) {
 210   if (!method->has_native_function()) {
 211     return NULL;
 212   }
 213 
 214   address current_entry = method->native_function();
 215 
 216   char dll_name[JVM_MAXPATHLEN];
 217   int offset;
 218   if (os::dll_address_to_library_name(current_entry, dll_name, sizeof(dll_name), &offset)) {
 219     char ebuf[32];
 220     void* dll = os::dll_load(dll_name, ebuf, sizeof(ebuf));
 221     if (dll != NULL) {
 222       // Compute complete JNI name for style
 223       stringStream st;
 224       if (os_style) os::print_jni_name_prefix_on(&st, args_size);
 225       st.print_raw(pure_name);
 226       st.print_raw(long_name);
 227       if (os_style) os::print_jni_name_suffix_on(&st, args_size);
 228       char* jni_name = st.as_string();
 229       address critical_entry = (address)os::dll_lookup(dll, jni_name);
 230       // Close the handle to avoid keeping the library alive if the native method holder is unloaded.
 231       // This is fine because the library is still kept alive by JNI (see JVM_LoadLibrary). As soon
 232       // as the holder class and the library are unloaded (see JVM_UnloadLibrary), the native wrapper
 233       // that calls 'critical_entry' becomes unreachable and is unloaded as well.
 234       os::dll_unload(dll);
 235       return critical_entry;
 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(const 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   // 1) Try JNI short style
 257   entry = lookup_style(method, pure_name, "",        args_size, true,  in_base_library, CHECK_NULL);
 258   if (entry != NULL) return entry;
 259 
 260   // Compute long name
 261   char* long_name = long_jni_name(method);
 262 
 263   // 2) Try JNI long style
 264   entry = lookup_style(method, pure_name, long_name, args_size, true,  in_base_library, CHECK_NULL);
 265   if (entry != NULL) return entry;
 266 
 267   // 3) Try JNI short style without os prefix/suffix
 268   entry = lookup_style(method, pure_name, "",        args_size, false, in_base_library, CHECK_NULL);
 269   if (entry != NULL) return entry;
 270 
 271   // 4) Try JNI long style without os prefix/suffix
 272   entry = lookup_style(method, pure_name, long_name, args_size, false, in_base_library, CHECK_NULL);
 273 
 274   return entry; // NULL indicates not found
 275 }
 276 
 277 // Check all the formats of native implementation name to see if there is one
 278 // for the specified method.
 279 address NativeLookup::lookup_critical_entry(const methodHandle& method) {
 280   if (!CriticalJNINatives) return NULL;
 281 
 282   if (method->is_synchronized() ||
 283       !method->is_static()) {
 284     // Only static non-synchronized methods are allowed
 285     return NULL;
 286   }
 287 
 288   ResourceMark rm;
 289   address entry = NULL;
 290 
 291   Symbol* signature = method->signature();
 292   for (int end = 0; end < signature->utf8_length(); end++) {
 293     if (signature->char_at(end) == 'L') {
 294       // Don't allow object types
 295       return NULL;
 296     }
 297   }
 298 
 299   // Compute critical name
 300   char* critical_name = critical_jni_name(method);
 301 
 302   // Compute argument size
 303   int args_size = method->size_of_parameters();
 304   for (SignatureStream ss(signature); !ss.at_return_type(); ss.next()) {
 305     if (ss.is_array()) {
 306       args_size += T_INT_size; // array length parameter
 307     }
 308   }
 309 
 310   // 1) Try JNI short style
 311   entry = lookup_critical_style(method, critical_name, "",        args_size, true);
 312   if (entry != NULL) return entry;
 313 
 314   // Compute long name
 315   char* long_name = long_jni_name(method);
 316 
 317   // 2) Try JNI long style
 318   entry = lookup_critical_style(method, critical_name, long_name, args_size, true);
 319   if (entry != NULL) return entry;
 320 
 321   // 3) Try JNI short style without os prefix/suffix
 322   entry = lookup_critical_style(method, critical_name, "",        args_size, false);
 323   if (entry != NULL) return entry;
 324 
 325   // 4) Try JNI long style without os prefix/suffix
 326   entry = lookup_critical_style(method, critical_name, long_name, args_size, false);
 327 
 328   return entry; // NULL indicates not found
 329 }
 330 
 331 // Check if there are any JVM TI prefixes which have been applied to the native method name.
 332 // If any are found, remove them before attemping the look up of the
 333 // native implementation again.
 334 // See SetNativeMethodPrefix in the JVM TI Spec for more details.
 335 address NativeLookup::lookup_entry_prefixed(const methodHandle& method, bool& in_base_library, TRAPS) {
 336 #if INCLUDE_JVMTI
 337   ResourceMark rm(THREAD);
 338 
 339   int prefix_count;
 340   char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
 341   char* in_name = method->name()->as_C_string();
 342   char* wrapper_name = in_name;
 343   // last applied prefix will be first -- go backwards
 344   for (int i = prefix_count-1; i >= 0; i--) {
 345     char* prefix = prefixes[i];
 346     size_t prefix_len = strlen(prefix);
 347     if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
 348       // has this prefix remove it
 349       wrapper_name += prefix_len;
 350     }
 351   }
 352   if (wrapper_name != in_name) {
 353     // we have a name for a wrapping method
 354     int wrapper_name_len = (int)strlen(wrapper_name);
 355     TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);
 356     if (wrapper_symbol != NULL) {
 357       Klass* k = method->method_holder();
 358       Method* wrapper_method = k->lookup_method(wrapper_symbol, 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(const 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   stringStream ss;
 384   ss.print("'");
 385   method->print_external_name(&ss);
 386   ss.print("'");
 387   THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(), ss.as_string());
 388 }
 389 
 390 
 391 address NativeLookup::lookup(const methodHandle& method, bool& in_base_library, TRAPS) {
 392   if (!method->has_native_function()) {
 393     address entry = lookup_base(method, in_base_library, CHECK_NULL);
 394     method->set_native_function(entry,
 395       Method::native_bind_event_is_interesting);
 396     // -verbose:jni printing
 397     if (PrintJNIResolving) {
 398       ResourceMark rm(THREAD);
 399       tty->print_cr("[Dynamic-linking native method %s.%s ... JNI]",
 400         method->method_holder()->external_name(),
 401         method->name()->as_C_string());
 402     }
 403   }
 404   return method->native_function();
 405 }
 406 
 407 address NativeLookup::base_library_lookup(const char* class_name, const char* method_name, const char* signature) {
 408   EXCEPTION_MARK;
 409   bool in_base_library = true;  // SharedRuntime inits some math methods.
 410   TempNewSymbol c_name = SymbolTable::new_symbol(class_name);
 411   TempNewSymbol m_name = SymbolTable::new_symbol(method_name);
 412   TempNewSymbol s_name = SymbolTable::new_symbol(signature);
 413 
 414   // Find the class
 415   Klass* k = SystemDictionary::resolve_or_fail(c_name, true, CATCH);
 416   InstanceKlass* klass  = InstanceKlass::cast(k);
 417 
 418   // Find method and invoke standard lookup
 419   methodHandle method (THREAD,
 420                        klass->uncached_lookup_method(m_name, s_name, Klass::find_overpass));
 421   address result = lookup(method, in_base_library, CATCH);
 422   assert(in_base_library, "must be in basic library");
 423   guarantee(result != NULL, "must be non NULL");
 424   return result;
 425 }