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 #ifdef TARGET_OS_FAMILY_linux
  45 # include "os_linux.inline.hpp"
  46 #endif
  47 #ifdef TARGET_OS_FAMILY_solaris
  48 # include "os_solaris.inline.hpp"
  49 #endif
  50 #ifdef TARGET_OS_FAMILY_windows
  51 # include "os_windows.inline.hpp"
  52 #endif
  53 #ifdef TARGET_OS_FAMILY_aix
  54 # include "os_aix.inline.hpp"
  55 #endif
  56 #ifdef TARGET_OS_FAMILY_bsd
  57 # include "os_bsd.inline.hpp"
  58 #endif
  59 
  60 
  61 static void mangle_name_on(outputStream* st, Symbol* name, int begin, int end) {
  62   char* bytes = (char*)name->bytes() + begin;
  63   char* end_bytes = (char*)name->bytes() + end;
  64   while (bytes < end_bytes) {
  65     jchar c;
  66     bytes = UTF8::next(bytes, &c);
  67     if (c <= 0x7f && isalnum(c)) {
  68       st->put((char) c);
  69     } else {
  70            if (c == '_') st->print("_1");
  71       else if (c == '/') st->print("_");
  72       else if (c == ';') st->print("_2");
  73       else if (c == '[') st->print("_3");
  74       else               st->print("_%.5x", c);
  75     }
  76   }
  77 }
  78 
  79 
  80 static void mangle_name_on(outputStream* st, Symbol* name) {
  81   mangle_name_on(st, name, 0, name->utf8_length());
  82 }
  83 
  84 
  85 char* NativeLookup::pure_jni_name(methodHandle method) {
  86   stringStream st;
  87   // Prefix
  88   st.print("Java_");
  89   // Klass name
  90   mangle_name_on(&st, method->klass_name());
  91   st.print("_");
  92   // Method name
  93   mangle_name_on(&st, method->name());
  94   return st.as_string();
  95 }
  96 
  97 
  98 char* NativeLookup::critical_jni_name(methodHandle method) {
  99   stringStream st;
 100   // Prefix
 101   st.print("JavaCritical_");
 102   // Klass name
 103   mangle_name_on(&st, method->klass_name());
 104   st.print("_");
 105   // Method name
 106   mangle_name_on(&st, method->name());
 107   return st.as_string();
 108 }
 109 
 110 
 111 char* NativeLookup::long_jni_name(methodHandle method) {
 112   // Signature ignore the wrapping parenteses and the trailing return type
 113   stringStream st;
 114   Symbol* signature = method->signature();
 115   st.print("__");
 116   // find ')'
 117   int end;
 118   for (end = 0; end < signature->utf8_length() && signature->byte_at(end) != ')'; end++);
 119   // skip first '('
 120   mangle_name_on(&st, signature, 1, end);
 121   return st.as_string();
 122 }
 123 
 124 extern "C" {
 125   void JNICALL JVM_RegisterUnsafeMethods(JNIEnv *env, jclass unsafecls);
 126   void JNICALL JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass unsafecls);
 127   void JNICALL JVM_RegisterPerfMethods(JNIEnv *env, jclass perfclass);
 128   void JNICALL JVM_RegisterWhiteBoxMethods(JNIEnv *env, jclass wbclass);
 129 }
 130 
 131 #define CC (char*)  /* cast a literal from (const char*) */
 132 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
 133 
 134 static JNINativeMethod lookup_special_native_methods[] = {
 135   { CC"Java_sun_misc_Unsafe_registerNatives",                      NULL, FN_PTR(JVM_RegisterUnsafeMethods)       },
 136   { CC"Java_java_lang_invoke_MethodHandleNatives_registerNatives", NULL, FN_PTR(JVM_RegisterMethodHandleMethods) },
 137   { CC"Java_sun_misc_Perf_registerNatives",                        NULL, FN_PTR(JVM_RegisterPerfMethods)         },
 138   { CC"Java_sun_hotspot_WhiteBox_registerNatives",                 NULL, FN_PTR(JVM_RegisterWhiteBoxMethods)     },



 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(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   KlassHandle   klass (THREAD, 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(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       return (address)os::dll_lookup(dll, jni_name);
 230     }
 231   }
 232 
 233   return NULL;
 234 }
 235 
 236 
 237 // Check all the formats of native implementation name to see if there is one
 238 // for the specified method.
 239 address NativeLookup::lookup_entry(methodHandle method, bool& in_base_library, TRAPS) {
 240   address entry = NULL;
 241   in_base_library = false;
 242   // Compute pure name
 243   char* pure_name = pure_jni_name(method);
 244 
 245   // Compute argument size
 246   int args_size = 1                             // JNIEnv
 247                 + (method->is_static() ? 1 : 0) // class for static methods
 248                 + method->size_of_parameters(); // actual parameters
 249 
 250 
 251   // 1) Try JNI short style
 252   entry = lookup_style(method, pure_name, "",        args_size, true,  in_base_library, CHECK_NULL);
 253   if (entry != NULL) return entry;
 254 
 255   // Compute long name
 256   char* long_name = long_jni_name(method);
 257 
 258   // 2) Try JNI long style
 259   entry = lookup_style(method, pure_name, long_name, args_size, true,  in_base_library, CHECK_NULL);
 260   if (entry != NULL) return entry;
 261 
 262   // 3) Try JNI short style without os prefix/suffix
 263   entry = lookup_style(method, pure_name, "",        args_size, false, in_base_library, CHECK_NULL);
 264   if (entry != NULL) return entry;
 265 
 266   // 4) Try JNI long style without os prefix/suffix
 267   entry = lookup_style(method, pure_name, long_name, args_size, false, in_base_library, CHECK_NULL);
 268 
 269   return entry; // NULL indicates not found
 270 }
 271 
 272 // Check all the formats of native implementation name to see if there is one
 273 // for the specified method.
 274 address NativeLookup::lookup_critical_entry(methodHandle method) {
 275   if (!CriticalJNINatives) return NULL;
 276 
 277   if (method->is_synchronized() ||
 278       !method->is_static()) {
 279     // Only static non-synchronized methods are allowed
 280     return NULL;
 281   }
 282 
 283   ResourceMark rm;
 284   address entry = NULL;
 285 
 286   Symbol* signature = method->signature();
 287   for (int end = 0; end < signature->utf8_length(); end++) {
 288     if (signature->byte_at(end) == 'L') {
 289       // Don't allow object types
 290       return NULL;
 291     }
 292   }
 293 
 294   // Compute critical name
 295   char* critical_name = critical_jni_name(method);
 296 
 297   // Compute argument size
 298   int args_size = 1                             // JNIEnv
 299                 + (method->is_static() ? 1 : 0) // class for static methods
 300                 + method->size_of_parameters(); // actual parameters
 301 
 302 
 303   // 1) Try JNI short style
 304   entry = lookup_critical_style(method, critical_name, "",        args_size, true);
 305   if (entry != NULL) return entry;
 306 
 307   // Compute long name
 308   char* long_name = long_jni_name(method);
 309 
 310   // 2) Try JNI long style
 311   entry = lookup_critical_style(method, critical_name, long_name, args_size, true);
 312   if (entry != NULL) return entry;
 313 
 314   // 3) Try JNI short style without os prefix/suffix
 315   entry = lookup_critical_style(method, critical_name, "",        args_size, false);
 316   if (entry != NULL) return entry;
 317 
 318   // 4) Try JNI long style without os prefix/suffix
 319   entry = lookup_critical_style(method, critical_name, long_name, args_size, false);
 320 
 321   return entry; // NULL indicates not found
 322 }
 323 
 324 // Check if there are any JVM TI prefixes which have been applied to the native method name.
 325 // If any are found, remove them before attemping the look up of the
 326 // native implementation again.
 327 // See SetNativeMethodPrefix in the JVM TI Spec for more details.
 328 address NativeLookup::lookup_entry_prefixed(methodHandle method, bool& in_base_library, TRAPS) {
 329 #if INCLUDE_JVMTI
 330   ResourceMark rm(THREAD);
 331 
 332   int prefix_count;
 333   char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
 334   char* in_name = method->name()->as_C_string();
 335   char* wrapper_name = in_name;
 336   // last applied prefix will be first -- go backwards
 337   for (int i = prefix_count-1; i >= 0; i--) {
 338     char* prefix = prefixes[i];
 339     size_t prefix_len = strlen(prefix);
 340     if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
 341       // has this prefix remove it
 342       wrapper_name += prefix_len;
 343     }
 344   }
 345   if (wrapper_name != in_name) {
 346     // we have a name for a wrapping method
 347     int wrapper_name_len = (int)strlen(wrapper_name);
 348     TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);
 349     if (wrapper_symbol != NULL) {
 350       KlassHandle kh(method->method_holder());
 351       Method* wrapper_method = kh()->lookup_method(wrapper_symbol,
 352                                                                   method->signature());
 353       if (wrapper_method != NULL && !wrapper_method->is_native()) {
 354         // we found a wrapper method, use its native entry
 355         method->set_is_prefixed_native();
 356         return lookup_entry(wrapper_method, in_base_library, THREAD);
 357       }
 358     }
 359   }
 360 #endif // INCLUDE_JVMTI
 361   return NULL;
 362 }
 363 
 364 address NativeLookup::lookup_base(methodHandle method, bool& in_base_library, TRAPS) {
 365   address entry = NULL;
 366   ResourceMark rm(THREAD);
 367 
 368   entry = lookup_entry(method, in_base_library, THREAD);
 369   if (entry != NULL) return entry;
 370 
 371   // standard native method resolution has failed.  Check if there are any
 372   // JVM TI prefixes which have been applied to the native method name.
 373   entry = lookup_entry_prefixed(method, in_base_library, THREAD);
 374   if (entry != NULL) return entry;
 375 
 376   // Native function not found, throw UnsatisfiedLinkError
 377   THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(),
 378               method->name_and_sig_as_C_string());
 379 }
 380 
 381 
 382 address NativeLookup::lookup(methodHandle method, bool& in_base_library, TRAPS) {
 383   if (!method->has_native_function()) {
 384     address entry = lookup_base(method, in_base_library, CHECK_NULL);
 385     method->set_native_function(entry,
 386       Method::native_bind_event_is_interesting);
 387     // -verbose:jni printing
 388     if (PrintJNIResolving) {
 389       ResourceMark rm(THREAD);
 390       tty->print_cr("[Dynamic-linking native method %s.%s ... JNI]",
 391         method->method_holder()->external_name(),
 392         method->name()->as_C_string());
 393     }
 394   }
 395   return method->native_function();
 396 }
 397 
 398 address NativeLookup::base_library_lookup(const char* class_name, const char* method_name, const char* signature) {
 399   EXCEPTION_MARK;
 400   bool in_base_library = true;  // SharedRuntime inits some math methods.
 401   TempNewSymbol c_name = SymbolTable::new_symbol(class_name,  CATCH);
 402   TempNewSymbol m_name = SymbolTable::new_symbol(method_name, CATCH);
 403   TempNewSymbol s_name = SymbolTable::new_symbol(signature,   CATCH);
 404 
 405   // Find the class
 406   Klass* k = SystemDictionary::resolve_or_fail(c_name, true, CATCH);
 407   instanceKlassHandle klass (THREAD, k);
 408 
 409   // Find method and invoke standard lookup
 410   methodHandle method (THREAD,
 411                        klass->uncached_lookup_method(m_name, s_name, Klass::find_overpass));
 412   address result = lookup(method, in_base_library, CATCH);
 413   assert(in_base_library, "must be in basic library");
 414   guarantee(result != NULL, "must be non NULL");
 415   return result;
 416 }
--- EOF ---