nativeLookup.cpp revision 0:a61af66fc99e 
1/*
2 * Copyright 1997-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25# include "incls/_precompiled.incl"
26# include "incls/_nativeLookup.cpp.incl"
27
28
29static void mangle_name_on(outputStream* st, symbolOop name, int begin, int end) {
30  char* bytes = (char*)name->bytes() + begin;
31  char* end_bytes = (char*)name->bytes() + end;
32  while (bytes < end_bytes) {
33    jchar c;
34    bytes = UTF8::next(bytes, &c);
35    if (c <= 0x7f && isalnum(c)) {
36      st->put((char) c);
37    } else {
38           if (c == '_') st->print("_1");
39      else if (c == '/') st->print("_");
40      else if (c == ';') st->print("_2");
41      else if (c == '[') st->print("_3");
42      else               st->print("_%.5x", c);
43    }
44  }
45}
46
47
48static void mangle_name_on(outputStream* st, symbolOop name) {
49  mangle_name_on(st, name, 0, name->utf8_length());
50}
51
52
53char* NativeLookup::pure_jni_name(methodHandle method) {
54  stringStream st;
55  // Prefix
56  st.print("Java_");
57  // Klass name
58  mangle_name_on(&st, method->klass_name());
59  st.print("_");
60  // Method name
61  mangle_name_on(&st, method->name());
62  return st.as_string();
63}
64
65
66char* NativeLookup::long_jni_name(methodHandle method) {
67  // Signature ignore the wrapping parenteses and the trailing return type
68  stringStream st;
69  symbolOop signature = method->signature();
70  st.print("__");
71  // find ')'
72  int end;
73  for (end = 0; end < signature->utf8_length() && signature->byte_at(end) != ')'; end++);
74  // skip first '('
75  mangle_name_on(&st, signature, 1, end);
76  return st.as_string();
77}
78
79extern "C" {
80  void JNICALL JVM_RegisterUnsafeMethods(JNIEnv *env, jclass unsafecls);
81  void JNICALL JVM_RegisterPerfMethods(JNIEnv *env, jclass perfclass);
82}
83
84static address lookup_special_native(char* jni_name) {
85  // NB: To ignore the jni prefix and jni postfix strstr is used matching.
86  if (!JDK_Version::is_gte_jdk14x_version()) {
87    // These functions only exist for compatibility with 1.3.1 and earlier
88    // Intercept ObjectOutputStream getPrimitiveFieldValues for faster serialization
89    if (strstr(jni_name, "Java_java_io_ObjectOutputStream_getPrimitiveFieldValues") != NULL) {
90      return CAST_FROM_FN_PTR(address, JVM_GetPrimitiveFieldValues);
91    }
92    // Intercept ObjectInputStream setPrimitiveFieldValues for faster serialization
93    if (strstr(jni_name, "Java_java_io_ObjectInputStream_setPrimitiveFieldValues") != NULL) {
94      return CAST_FROM_FN_PTR(address, JVM_SetPrimitiveFieldValues);
95    }
96  }
97  if (strstr(jni_name, "Java_sun_misc_Unsafe_registerNatives") != NULL) {
98    return CAST_FROM_FN_PTR(address, JVM_RegisterUnsafeMethods);
99  }
100  if (strstr(jni_name, "Java_sun_misc_Perf_registerNatives") != NULL) {
101    return CAST_FROM_FN_PTR(address, JVM_RegisterPerfMethods);
102  }
103
104  return NULL;
105}
106
107address NativeLookup::lookup_style(methodHandle method, char* pure_name, const char* long_name, int args_size, bool os_style, bool& in_base_library, TRAPS) {
108  address entry;
109  // Compute complete JNI name for style
110  stringStream st;
111  if (os_style) os::print_jni_name_prefix_on(&st, args_size);
112  st.print_raw(pure_name);
113  st.print_raw(long_name);
114  if (os_style) os::print_jni_name_suffix_on(&st, args_size);
115  char* jni_name = st.as_string();
116
117  // If the loader is null we have a system class, so we attempt a lookup in
118  // the native Java library. This takes care of any bootstrapping problems.
119  // Note: It is critical for bootstrapping that Java_java_lang_ClassLoader_00024NativeLibrary_find
120  // gets found the first time around - otherwise an infinite loop can occure. This is
121  // another VM/library dependency
122  Handle loader(THREAD,
123                instanceKlass::cast(method->method_holder())->class_loader());
124  if (loader.is_null()) {
125    entry = lookup_special_native(jni_name);
126    if (entry == NULL) {
127       entry = (address) hpi::dll_lookup(os::native_java_library(), jni_name);
128    }
129    if (entry != NULL) {
130      in_base_library = true;
131      return entry;
132    }
133  }
134
135  // Otherwise call static method findNative in ClassLoader
136  KlassHandle   klass (THREAD, SystemDictionary::classloader_klass());
137  Handle name_arg = java_lang_String::create_from_str(jni_name, CHECK_NULL);
138
139  JavaValue result(T_LONG);
140  JavaCalls::call_static(&result,
141                         klass,
142                         vmSymbolHandles::findNative_name(),
143                         vmSymbolHandles::classloader_string_long_signature(),
144                         // Arguments
145                         loader,
146                         name_arg,
147                         CHECK_NULL);
148  entry = (address) (intptr_t) result.get_jlong();
149
150  if (entry == NULL) {
151    // findNative didn't find it, if there are any agent libraries look in them
152    AgentLibrary* agent;
153    for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
154      entry = (address) hpi::dll_lookup(agent->os_lib(), jni_name);
155      if (entry != NULL) {
156        return entry;
157      }
158    }
159  }
160
161  return entry;
162}
163
164
165// Check all the formats of native implementation name to see if there is one
166// for the specified method.
167address NativeLookup::lookup_entry(methodHandle method, bool& in_base_library, TRAPS) {
168  address entry = NULL;
169  in_base_library = false;
170  // Compute pure name
171  char* pure_name = pure_jni_name(method);
172
173  // Compute argument size
174  int args_size = 1                             // JNIEnv
175                + (method->is_static() ? 1 : 0) // class for static methods
176                + method->size_of_parameters(); // actual parameters
177
178
179  // 1) Try JNI short style
180  entry = lookup_style(method, pure_name, "",        args_size, true,  in_base_library, CHECK_NULL);
181  if (entry != NULL) return entry;
182
183  // Compute long name
184  char* long_name = long_jni_name(method);
185
186  // 2) Try JNI long style
187  entry = lookup_style(method, pure_name, long_name, args_size, true,  in_base_library, CHECK_NULL);
188  if (entry != NULL) return entry;
189
190  // 3) Try JNI short style without os prefix/suffix
191  entry = lookup_style(method, pure_name, "",        args_size, false, in_base_library, CHECK_NULL);
192  if (entry != NULL) return entry;
193
194  // 4) Try JNI long style without os prefix/suffix
195  entry = lookup_style(method, pure_name, long_name, args_size, false, in_base_library, CHECK_NULL);
196
197  return entry; // NULL indicates not found
198}
199
200// Check if there are any JVM TI prefixes which have been applied to the native method name.
201// If any are found, remove them before attemping the look up of the
202// native implementation again.
203// See SetNativeMethodPrefix in the JVM TI Spec for more details.
204address NativeLookup::lookup_entry_prefixed(methodHandle method, bool& in_base_library, TRAPS) {
205  ResourceMark rm(THREAD);
206
207  int prefix_count;
208  char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
209  char* in_name = method->name()->as_C_string();
210  char* wrapper_name = in_name;
211  // last applied prefix will be first -- go backwards
212  for (int i = prefix_count-1; i >= 0; i--) {
213    char* prefix = prefixes[i];
214    size_t prefix_len = strlen(prefix);
215    if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
216      // has this prefix remove it
217      wrapper_name += prefix_len;
218    }
219  }
220  if (wrapper_name != in_name) {
221    // we have a name for a wrapping method
222    int wrapper_name_len = (int)strlen(wrapper_name);
223    symbolHandle wrapper_symbol(THREAD, SymbolTable::probe(wrapper_name, wrapper_name_len));
224    if (!wrapper_symbol.is_null()) {
225      KlassHandle kh(method->method_holder());
226      methodOop wrapper_method = Klass::cast(kh())->lookup_method(wrapper_symbol(),
227                                                                  method->signature());
228      if (wrapper_method != NULL && !wrapper_method->is_native()) {
229        // we found a wrapper method, use its native entry
230        method->set_is_prefixed_native();
231        return lookup_entry(wrapper_method, in_base_library, THREAD);
232      }
233    }
234  }
235  return NULL;
236}
237
238address NativeLookup::lookup_base(methodHandle method, bool& in_base_library, TRAPS) {
239  address entry = NULL;
240  ResourceMark rm(THREAD);
241
242  entry = lookup_entry(method, in_base_library, THREAD);
243  if (entry != NULL) return entry;
244
245  // standard native method resolution has failed.  Check if there are any
246  // JVM TI prefixes which have been applied to the native method name.
247  entry = lookup_entry_prefixed(method, in_base_library, THREAD);
248  if (entry != NULL) return entry;
249
250  // Native function not found, throw UnsatisfiedLinkError
251  THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(),
252              method->name_and_sig_as_C_string());
253}
254
255
256address NativeLookup::lookup(methodHandle method, bool& in_base_library, TRAPS) {
257  if (!method->has_native_function()) {
258    address entry = lookup_base(method, in_base_library, CHECK_NULL);
259    method->set_native_function(entry,
260      methodOopDesc::native_bind_event_is_interesting);
261    // -verbose:jni printing
262    if (PrintJNIResolving) {
263      ResourceMark rm(THREAD);
264      tty->print_cr("[Dynamic-linking native method %s.%s ... JNI]",
265        Klass::cast(method->method_holder())->external_name(),
266        method->name()->as_C_string());
267    }
268  }
269  return method->native_function();
270}
271
272address NativeLookup::base_library_lookup(const char* class_name, const char* method_name, const char* signature) {
273  EXCEPTION_MARK;
274  bool in_base_library = true;  // SharedRuntime inits some math methods.
275  symbolHandle c_name = oopFactory::new_symbol_handle(class_name,  CATCH);
276  symbolHandle m_name = oopFactory::new_symbol_handle(method_name, CATCH);
277  symbolHandle s_name = oopFactory::new_symbol_handle(signature,   CATCH);
278
279  // Find the class
280  klassOop k = SystemDictionary::resolve_or_fail(c_name, true, CATCH);
281  instanceKlassHandle klass (THREAD, k);
282
283  // Find method and invoke standard lookup
284  methodHandle method (THREAD,
285                       klass->uncached_lookup_method(m_name(), s_name()));
286  address result = lookup(method, in_base_library, CATCH);
287  assert(in_base_library, "must be in basic library");
288  guarantee(result != NULL, "must be non NULL");
289  return result;
290}
291