1 /*
2 * Copyright (c) 1997, 2015, 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
45
46 static void mangle_name_on(outputStream* st, Symbol* name, int begin, int end) {
47 char* bytes = (char*)name->bytes() + begin;
48 char* end_bytes = (char*)name->bytes() + end;
49 while (bytes < end_bytes) {
50 jchar c;
51 bytes = UTF8::next(bytes, &c);
52 if (c <= 0x7f && isalnum(c)) {
53 st->put((char) c);
54 } else {
55 if (c == '_') st->print("_1");
56 else if (c == '/') st->print("_");
57 else if (c == ';') st->print("_2");
58 else if (c == '[') st->print("_3");
59 else st->print("_%.5x", c);
60 }
61 }
62 }
63
64
65 static void mangle_name_on(outputStream* st, Symbol* name) {
66 mangle_name_on(st, name, 0, name->utf8_length());
67 }
68
69
70 char* NativeLookup::pure_jni_name(methodHandle method) {
71 stringStream st;
72 // Prefix
73 st.print("Java_");
74 // Klass name
75 mangle_name_on(&st, method->klass_name());
76 st.print("_");
77 // Method name
78 mangle_name_on(&st, method->name());
79 return st.as_string();
80 }
81
82
83 char* NativeLookup::critical_jni_name(methodHandle method) {
84 stringStream st;
85 // Prefix
86 st.print("JavaCritical_");
87 // Klass name
88 mangle_name_on(&st, method->klass_name());
89 st.print("_");
90 // Method name
91 mangle_name_on(&st, method->name());
92 return st.as_string();
93 }
94
95
96 char* NativeLookup::long_jni_name(methodHandle method) {
97 // Signature ignore the wrapping parenteses and the trailing return type
98 stringStream st;
99 Symbol* signature = method->signature();
100 st.print("__");
101 // find ')'
102 int end;
103 for (end = 0; end < signature->utf8_length() && signature->byte_at(end) != ')'; end++);
104 // skip first '('
105 mangle_name_on(&st, signature, 1, end);
106 return st.as_string();
107 }
108
109 extern "C" {
110 void JNICALL JVM_RegisterUnsafeMethods(JNIEnv *env, jclass unsafecls);
111 void JNICALL JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass unsafecls);
112 void JNICALL JVM_RegisterPerfMethods(JNIEnv *env, jclass perfclass);
113 void JNICALL JVM_RegisterWhiteBoxMethods(JNIEnv *env, jclass wbclass);
114 }
115
116 #define CC (char*) /* cast a literal from (const char*) */
117 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
118
119 static JNINativeMethod lookup_special_native_methods[] = {
120 { CC"Java_sun_misc_Unsafe_registerNatives", NULL, FN_PTR(JVM_RegisterUnsafeMethods) },
121 { CC"Java_java_lang_invoke_MethodHandleNatives_registerNatives", NULL, FN_PTR(JVM_RegisterMethodHandleMethods) },
122 { CC"Java_sun_misc_Perf_registerNatives", NULL, FN_PTR(JVM_RegisterPerfMethods) },
123 { CC"Java_sun_hotspot_WhiteBox_registerNatives", NULL, FN_PTR(JVM_RegisterWhiteBoxMethods) },
124 };
125
126 static address lookup_special_native(char* jni_name) {
127 int count = sizeof(lookup_special_native_methods) / sizeof(JNINativeMethod);
128 for (int i = 0; i < count; i++) {
129 // NB: To ignore the jni prefix and jni postfix strstr is used matching.
130 if (strstr(jni_name, lookup_special_native_methods[i].name) != NULL) {
131 return CAST_FROM_FN_PTR(address, lookup_special_native_methods[i].fnPtr);
132 }
133 }
134 return NULL;
135 }
136
137 address NativeLookup::lookup_style(methodHandle method, char* pure_name, const char* long_name, int args_size, bool os_style, bool& in_base_library, TRAPS) {
138 address entry;
139 // Compute complete JNI name for style
140 stringStream st;
141 if (os_style) os::print_jni_name_prefix_on(&st, args_size);
142 st.print_raw(pure_name);
143 st.print_raw(long_name);
144 if (os_style) os::print_jni_name_suffix_on(&st, args_size);
145 char* jni_name = st.as_string();
146
147 // If the loader is null we have a system class, so we attempt a lookup in
148 // the native Java library. This takes care of any bootstrapping problems.
149 // Note: It is critical for bootstrapping that Java_java_lang_ClassLoader_00024NativeLibrary_find
150 // gets found the first time around - otherwise an infinite loop can occure. This is
151 // another VM/library dependency
152 Handle loader(THREAD, method->method_holder()->class_loader());
153 if (loader.is_null()) {
154 entry = lookup_special_native(jni_name);
155 if (entry == NULL) {
156 entry = (address) os::dll_lookup(os::native_java_library(), jni_name);
157 }
158 if (entry != NULL) {
159 in_base_library = true;
160 return entry;
161 }
162 }
163
164 // Otherwise call static method findNative in ClassLoader
165 KlassHandle klass (THREAD, SystemDictionary::ClassLoader_klass());
166 Handle name_arg = java_lang_String::create_from_str(jni_name, CHECK_NULL);
167
168 JavaValue result(T_LONG);
169 JavaCalls::call_static(&result,
170 klass,
171 vmSymbols::findNative_name(),
172 vmSymbols::classloader_string_long_signature(),
173 // Arguments
174 loader,
175 name_arg,
176 CHECK_NULL);
177 entry = (address) (intptr_t) result.get_jlong();
178
179 if (entry == NULL) {
180 // findNative didn't find it, if there are any agent libraries look in them
181 AgentLibrary* agent;
182 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
183 entry = (address) os::dll_lookup(agent->os_lib(), jni_name);
184 if (entry != NULL) {
185 return entry;
186 }
187 }
188 }
189
190 return entry;
191 }
192
193
194 address NativeLookup::lookup_critical_style(methodHandle method, char* pure_name, const char* long_name, int args_size, bool os_style) {
195 if (!method->has_native_function()) {
196 return NULL;
197 }
198
199 address current_entry = method->native_function();
200
201 char dll_name[JVM_MAXPATHLEN];
202 int offset;
203 if (os::dll_address_to_library_name(current_entry, dll_name, sizeof(dll_name), &offset)) {
204 char ebuf[32];
205 void* dll = os::dll_load(dll_name, ebuf, sizeof(ebuf));
206 if (dll != NULL) {
207 // Compute complete JNI name for style
208 stringStream st;
209 if (os_style) os::print_jni_name_prefix_on(&st, args_size);
210 st.print_raw(pure_name);
211 st.print_raw(long_name);
212 if (os_style) os::print_jni_name_suffix_on(&st, args_size);
213 char* jni_name = st.as_string();
214 return (address)os::dll_lookup(dll, jni_name);
215 }
216 }
217
218 return NULL;
219 }
220
221
222 // Check all the formats of native implementation name to see if there is one
223 // for the specified method.
224 address NativeLookup::lookup_entry(methodHandle method, bool& in_base_library, TRAPS) {
225 address entry = NULL;
226 in_base_library = false;
227 // Compute pure name
228 char* pure_name = pure_jni_name(method);
229
230 // Compute argument size
231 int args_size = 1 // JNIEnv
232 + (method->is_static() ? 1 : 0) // class for static methods
233 + method->size_of_parameters(); // actual parameters
234
235
236 // 1) Try JNI short style
237 entry = lookup_style(method, pure_name, "", args_size, true, in_base_library, CHECK_NULL);
238 if (entry != NULL) return entry;
239
240 // Compute long name
241 char* long_name = long_jni_name(method);
242
243 // 2) Try JNI long style
244 entry = lookup_style(method, pure_name, long_name, args_size, true, in_base_library, CHECK_NULL);
245 if (entry != NULL) return entry;
246
247 // 3) Try JNI short style without os prefix/suffix
248 entry = lookup_style(method, pure_name, "", args_size, false, in_base_library, CHECK_NULL);
249 if (entry != NULL) return entry;
250
251 // 4) Try JNI long style without os prefix/suffix
252 entry = lookup_style(method, pure_name, long_name, args_size, false, in_base_library, CHECK_NULL);
253
254 return entry; // NULL indicates not found
255 }
256
257 // Check all the formats of native implementation name to see if there is one
258 // for the specified method.
259 address NativeLookup::lookup_critical_entry(methodHandle method) {
260 if (!CriticalJNINatives) return NULL;
261
262 if (method->is_synchronized() ||
263 !method->is_static()) {
264 // Only static non-synchronized methods are allowed
265 return NULL;
266 }
267
268 ResourceMark rm;
269 address entry = NULL;
270
271 Symbol* signature = method->signature();
272 for (int end = 0; end < signature->utf8_length(); end++) {
273 if (signature->byte_at(end) == 'L') {
274 // Don't allow object types
275 return NULL;
276 }
277 }
278
279 // Compute critical name
280 char* critical_name = critical_jni_name(method);
281
282 // Compute argument size
283 int args_size = 1 // JNIEnv
284 + (method->is_static() ? 1 : 0) // class for static methods
285 + method->size_of_parameters(); // actual parameters
286
287
288 // 1) Try JNI short style
289 entry = lookup_critical_style(method, critical_name, "", args_size, true);
290 if (entry != NULL) return entry;
291
292 // Compute long name
293 char* long_name = long_jni_name(method);
294
295 // 2) Try JNI long style
296 entry = lookup_critical_style(method, critical_name, long_name, args_size, true);
297 if (entry != NULL) return entry;
298
299 // 3) Try JNI short style without os prefix/suffix
300 entry = lookup_critical_style(method, critical_name, "", args_size, false);
301 if (entry != NULL) return entry;
302
303 // 4) Try JNI long style without os prefix/suffix
304 entry = lookup_critical_style(method, critical_name, long_name, args_size, false);
305
306 return entry; // NULL indicates not found
307 }
308
309 // Check if there are any JVM TI prefixes which have been applied to the native method name.
310 // If any are found, remove them before attemping the look up of the
311 // native implementation again.
312 // See SetNativeMethodPrefix in the JVM TI Spec for more details.
313 address NativeLookup::lookup_entry_prefixed(methodHandle method, bool& in_base_library, TRAPS) {
314 #if INCLUDE_JVMTI
315 ResourceMark rm(THREAD);
316
317 int prefix_count;
318 char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
319 char* in_name = method->name()->as_C_string();
320 char* wrapper_name = in_name;
321 // last applied prefix will be first -- go backwards
322 for (int i = prefix_count-1; i >= 0; i--) {
323 char* prefix = prefixes[i];
324 size_t prefix_len = strlen(prefix);
325 if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
326 // has this prefix remove it
327 wrapper_name += prefix_len;
328 }
329 }
330 if (wrapper_name != in_name) {
331 // we have a name for a wrapping method
332 int wrapper_name_len = (int)strlen(wrapper_name);
333 TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);
334 if (wrapper_symbol != NULL) {
335 KlassHandle kh(method->method_holder());
336 Method* wrapper_method = kh()->lookup_method(wrapper_symbol,
337 method->signature());
338 if (wrapper_method != NULL && !wrapper_method->is_native()) {
339 // we found a wrapper method, use its native entry
340 method->set_is_prefixed_native();
341 return lookup_entry(wrapper_method, in_base_library, THREAD);
342 }
343 }
344 }
345 #endif // INCLUDE_JVMTI
346 return NULL;
347 }
348
349 address NativeLookup::lookup_base(methodHandle method, bool& in_base_library, TRAPS) {
350 address entry = NULL;
351 ResourceMark rm(THREAD);
352
353 entry = lookup_entry(method, in_base_library, THREAD);
354 if (entry != NULL) return entry;
355
356 // standard native method resolution has failed. Check if there are any
357 // JVM TI prefixes which have been applied to the native method name.
358 entry = lookup_entry_prefixed(method, in_base_library, THREAD);
359 if (entry != NULL) return entry;
360
361 // Native function not found, throw UnsatisfiedLinkError
362 THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(),
363 method->name_and_sig_as_C_string());
364 }
365
366
367 address NativeLookup::lookup(methodHandle method, bool& in_base_library, TRAPS) {
368 if (!method->has_native_function()) {
369 address entry = lookup_base(method, in_base_library, CHECK_NULL);
370 method->set_native_function(entry,
371 Method::native_bind_event_is_interesting);
372 // -verbose:jni printing
373 if (PrintJNIResolving) {
374 ResourceMark rm(THREAD);
375 tty->print_cr("[Dynamic-linking native method %s.%s ... JNI]",
376 method->method_holder()->external_name(),
377 method->name()->as_C_string());
378 }
379 }
380 return method->native_function();
381 }
382
383 address NativeLookup::base_library_lookup(const char* class_name, const char* method_name, const char* signature) {
384 EXCEPTION_MARK;
385 bool in_base_library = true; // SharedRuntime inits some math methods.
386 TempNewSymbol c_name = SymbolTable::new_symbol(class_name, CATCH);
387 TempNewSymbol m_name = SymbolTable::new_symbol(method_name, CATCH);
388 TempNewSymbol s_name = SymbolTable::new_symbol(signature, CATCH);
389
390 // Find the class
391 Klass* k = SystemDictionary::resolve_or_fail(c_name, true, CATCH);
392 instanceKlassHandle klass (THREAD, k);
393
394 // Find method and invoke standard lookup
395 methodHandle method (THREAD,
396 klass->uncached_lookup_method(m_name, s_name, Klass::find_overpass));
397 address result = lookup(method, in_base_library, CATCH);
398 assert(in_base_library, "must be in basic library");
399 guarantee(result != NULL, "must be non NULL");
400 return result;
401 }