1 /*
2 * Copyright (c) 1997, 2020, 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 "logging/log.hpp"
31 #include "logging/logTag.hpp"
32 #include "memory/oopFactory.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "oops/instanceKlass.hpp"
35 #include "oops/method.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "oops/symbol.hpp"
38 #include "prims/jvm_misc.hpp"
39 #include "prims/nativeLookup.hpp"
40 #include "prims/unsafe.hpp"
41 #include "runtime/arguments.hpp"
42 #include "runtime/handles.inline.hpp"
43 #include "runtime/interfaceSupport.inline.hpp"
44 #include "runtime/javaCalls.hpp"
45 #include "runtime/os.inline.hpp"
46 #include "runtime/sharedRuntime.hpp"
47 #include "runtime/signature.hpp"
48 #include "utilities/macros.hpp"
49 #include "utilities/utf8.hpp"
50 #if INCLUDE_JFR
51 #include "jfr/jfr.hpp"
52 #endif
53
54 static void mangle_name_on(outputStream* st, Symbol* name, int begin, int end) {
55 char* bytes = (char*)name->bytes() + begin;
56 char* end_bytes = (char*)name->bytes() + end;
57 while (bytes < end_bytes) {
58 jchar c;
59 bytes = UTF8::next(bytes, &c);
60 if (c <= 0x7f && isalnum(c)) {
61 st->put((char) c);
62 } else {
63 if (c == '_') st->print("_1");
64 else if (c == '/') st->print("_");
65 else if (c == ';') st->print("_2");
66 else if (c == '[') st->print("_3");
67 else st->print("_%.5x", c);
68 }
69 }
70 }
71
72
73 static void mangle_name_on(outputStream* st, Symbol* name) {
74 mangle_name_on(st, name, 0, name->utf8_length());
75 }
76
77
78 char* NativeLookup::pure_jni_name(const methodHandle& method) {
79 stringStream st;
80 // Prefix
81 st.print("Java_");
82 // Klass name
83 mangle_name_on(&st, method->klass_name());
84 st.print("_");
85 // Method name
86 mangle_name_on(&st, method->name());
87 return st.as_string();
88 }
89
90
91 char* NativeLookup::critical_jni_name(const methodHandle& method) {
92 stringStream st;
93 // Prefix
94 st.print("JavaCritical_");
95 // Klass name
96 mangle_name_on(&st, method->klass_name());
97 st.print("_");
98 // Method name
99 mangle_name_on(&st, method->name());
100 return st.as_string();
101 }
102
103
104 char* NativeLookup::long_jni_name(const methodHandle& method) {
105 // Signature ignore the wrapping parenteses and the trailing return type
106 stringStream st;
107 Symbol* signature = method->signature();
108 st.print("__");
109 // find ')'
110 int end;
111 for (end = 0; end < signature->utf8_length() && signature->char_at(end) != JVM_SIGNATURE_ENDFUNC; end++);
112 // skip first '('
113 mangle_name_on(&st, signature, 1, end);
114 return st.as_string();
115 }
116
117 extern "C" {
118 void JNICALL JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass unsafecls);
119 void JNICALL JVM_RegisterPerfMethods(JNIEnv *env, jclass perfclass);
120 void JNICALL JVM_RegisterWhiteBoxMethods(JNIEnv *env, jclass wbclass);
121 void JNICALL JVM_RegisterVectorSupportMethods(JNIEnv *env, jclass vsclass);
122 #if INCLUDE_JVMCI
123 jobject JNICALL JVM_GetJVMCIRuntime(JNIEnv *env, jclass c);
124 void JNICALL JVM_RegisterJVMCINatives(JNIEnv *env, jclass compilerToVMClass);
125 #endif
126 }
127
128 #define CC (char*) /* cast a literal from (const char*) */
129 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
130
131 static JNINativeMethod lookup_special_native_methods[] = {
132 { CC"Java_jdk_internal_misc_Unsafe_registerNatives", NULL, FN_PTR(JVM_RegisterJDKInternalMiscUnsafeMethods) },
133 { CC"Java_java_lang_invoke_MethodHandleNatives_registerNatives", NULL, FN_PTR(JVM_RegisterMethodHandleMethods) },
134 { CC"Java_jdk_internal_perf_Perf_registerNatives", NULL, FN_PTR(JVM_RegisterPerfMethods) },
135 { CC"Java_sun_hotspot_WhiteBox_registerNatives", NULL, FN_PTR(JVM_RegisterWhiteBoxMethods) },
136 { CC"Java_jdk_internal_vm_vector_VectorSupport_registerNatives", NULL, FN_PTR(JVM_RegisterVectorSupportMethods)},
137 #if INCLUDE_JVMCI
138 { CC"Java_jdk_vm_ci_runtime_JVMCI_initializeRuntime", NULL, FN_PTR(JVM_GetJVMCIRuntime) },
139 { CC"Java_jdk_vm_ci_hotspot_CompilerToVM_registerNatives", NULL, FN_PTR(JVM_RegisterJVMCINatives) },
140 #endif
141 #if INCLUDE_JFR
142 { CC"Java_jdk_jfr_internal_JVM_registerNatives", NULL, FN_PTR(jfr_register_natives) },
143 #endif
144 };
145
146 static address lookup_special_native(const char* jni_name) {
147 int count = sizeof(lookup_special_native_methods) / sizeof(JNINativeMethod);
148 for (int i = 0; i < count; i++) {
149 // NB: To ignore the jni prefix and jni postfix strstr is used matching.
150 if (strstr(jni_name, lookup_special_native_methods[i].name) != NULL) {
151 return CAST_FROM_FN_PTR(address, lookup_special_native_methods[i].fnPtr);
152 }
153 }
154 return NULL;
155 }
156
157 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) {
158 address entry;
159 const char* jni_name = compute_complete_jni_name(pure_name, long_name, args_size, os_style);
160
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_findNative
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 const char* NativeLookup::compute_complete_jni_name(const char* pure_name, const char* long_name, int args_size, bool os_style) {
209 stringStream st;
210 if (os_style) {
211 os::print_jni_name_prefix_on(&st, args_size);
212 }
213
214 st.print_raw(pure_name);
215 st.print_raw(long_name);
216 if (os_style) {
217 os::print_jni_name_suffix_on(&st, args_size);
218 }
219
220 return st.as_string();
221 }
222
223 address NativeLookup::lookup_critical_style(void* dll, const char* pure_name, const char* long_name, int args_size, bool os_style) {
224 const char* jni_name = compute_complete_jni_name(pure_name, long_name, args_size, os_style);
225 assert(dll != NULL, "dll must be loaded");
226 return (address)os::dll_lookup(dll, jni_name);
227 }
228
229 // Check all the formats of native implementation name to see if there is one
230 // for the specified method.
231 address NativeLookup::lookup_entry(const methodHandle& method, bool& in_base_library, TRAPS) {
232 address entry = NULL;
233 in_base_library = false;
234 // Compute pure name
235 char* pure_name = pure_jni_name(method);
236
237 // Compute argument size
238 int args_size = 1 // JNIEnv
239 + (method->is_static() ? 1 : 0) // class for static methods
240 + method->size_of_parameters(); // actual parameters
241
242 // 1) Try JNI short style
243 entry = lookup_style(method, pure_name, "", args_size, true, in_base_library, CHECK_NULL);
244 if (entry != NULL) return entry;
245
246 // Compute long name
247 char* long_name = long_jni_name(method);
248
249 // 2) Try JNI long style
250 entry = lookup_style(method, pure_name, long_name, args_size, true, in_base_library, CHECK_NULL);
251 if (entry != NULL) return entry;
252
253 // 3) Try JNI short style without os prefix/suffix
254 entry = lookup_style(method, pure_name, "", args_size, false, in_base_library, CHECK_NULL);
255 if (entry != NULL) return entry;
256
257 // 4) Try JNI long style without os prefix/suffix
258 entry = lookup_style(method, pure_name, long_name, args_size, false, in_base_library, CHECK_NULL);
259
260 return entry; // NULL indicates not found
261 }
262
263 // Check all the formats of native implementation name to see if there is one
264 // for the specified method.
265 address NativeLookup::lookup_critical_entry(const methodHandle& method) {
266 assert(CriticalJNINatives, "or should not be here");
267
268 if (method->is_synchronized() ||
269 !method->is_static()) {
270 // Only static non-synchronized methods are allowed
271 return NULL;
272 }
273
274 ResourceMark rm;
275
276 Symbol* signature = method->signature();
277 for (int end = 0; end < signature->utf8_length(); end++) {
278 if (signature->char_at(end) == 'L') {
279 // Don't allow object types
280 return NULL;
281 }
282 }
283
284 // Compute argument size
285 int args_size = method->size_of_parameters();
286 for (SignatureStream ss(signature); !ss.at_return_type(); ss.next()) {
287 if (ss.is_array()) {
288 args_size += T_INT_size; // array length parameter
289 }
290 }
291
292 // dll handling requires I/O. Don't do that while in _thread_in_vm (safepoint may get requested).
293 ThreadToNativeFromVM thread_in_native(JavaThread::current());
294
295 void* dll = dll_load(method);
296 address entry = NULL;
297
298 if (dll != NULL) {
299 entry = lookup_critical_style(dll, method, args_size);
300 // Close the handle to avoid keeping the library alive if the native method holder is unloaded.
301 // This is fine because the library is still kept alive by JNI (see JVM_LoadLibrary). As soon
302 // as the holder class and the library are unloaded (see JVM_UnloadLibrary), the native wrapper
303 // that calls 'critical_entry' becomes unreachable and is unloaded as well.
304 os::dll_unload(dll);
305 }
306
307 return entry; // NULL indicates not found
308 }
309
310 void* NativeLookup::dll_load(const methodHandle& method) {
311 if (method->has_native_function()) {
312
313 address current_entry = method->native_function();
314
315 char dll_name[JVM_MAXPATHLEN];
316 int offset;
317 if (os::dll_address_to_library_name(current_entry, dll_name, sizeof(dll_name), &offset)) {
318 char ebuf[32];
319 return os::dll_load(dll_name, ebuf, sizeof(ebuf));
320 }
321 }
322
323 return NULL;
324 }
325
326 address NativeLookup::lookup_critical_style(void* dll, const methodHandle& method, int args_size) {
327 address entry = NULL;
328 const char* critical_name = critical_jni_name(method);
329
330 // 1) Try JNI short style
331 entry = lookup_critical_style(dll, critical_name, "", args_size, true);
332 if (entry != NULL) {
333 return entry;
334 }
335
336 const char* long_name = long_jni_name(method);
337
338 // 2) Try JNI long style
339 entry = lookup_critical_style(dll, critical_name, long_name, args_size, true);
340 if (entry != NULL) {
341 return entry;
342 }
343
344 // 3) Try JNI short style without os prefix/suffix
345 entry = lookup_critical_style(dll, critical_name, "", args_size, false);
346 if (entry != NULL) {
347 return entry;
348 }
349
350 // 4) Try JNI long style without os prefix/suffix
351 return lookup_critical_style(dll, critical_name, long_name, args_size, false);
352 }
353
354 // Check if there are any JVM TI prefixes which have been applied to the native method name.
355 // If any are found, remove them before attemping the look up of the
356 // native implementation again.
357 // See SetNativeMethodPrefix in the JVM TI Spec for more details.
358 address NativeLookup::lookup_entry_prefixed(const methodHandle& method, bool& in_base_library, TRAPS) {
359 #if INCLUDE_JVMTI
360 ResourceMark rm(THREAD);
361
362 int prefix_count;
363 char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
364 char* in_name = method->name()->as_C_string();
365 char* wrapper_name = in_name;
366 // last applied prefix will be first -- go backwards
367 for (int i = prefix_count-1; i >= 0; i--) {
368 char* prefix = prefixes[i];
369 size_t prefix_len = strlen(prefix);
370 if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
371 // has this prefix remove it
372 wrapper_name += prefix_len;
373 }
374 }
375 if (wrapper_name != in_name) {
376 // we have a name for a wrapping method
377 int wrapper_name_len = (int)strlen(wrapper_name);
378 TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);
379 if (wrapper_symbol != NULL) {
380 Klass* k = method->method_holder();
381 Method* wrapper_method = k->lookup_method(wrapper_symbol, method->signature());
382 if (wrapper_method != NULL && !wrapper_method->is_native()) {
383 // we found a wrapper method, use its native entry
384 method->set_is_prefixed_native();
385 return lookup_entry(methodHandle(THREAD, wrapper_method), in_base_library, THREAD);
386 }
387 }
388 }
389 #endif // INCLUDE_JVMTI
390 return NULL;
391 }
392
393 address NativeLookup::lookup_base(const methodHandle& method, bool& in_base_library, TRAPS) {
394 address entry = NULL;
395 ResourceMark rm(THREAD);
396
397 entry = lookup_entry(method, in_base_library, THREAD);
398 if (entry != NULL) return entry;
399
400 // standard native method resolution has failed. Check if there are any
401 // JVM TI prefixes which have been applied to the native method name.
402 entry = lookup_entry_prefixed(method, in_base_library, THREAD);
403 if (entry != NULL) return entry;
404
405 // Native function not found, throw UnsatisfiedLinkError
406 stringStream ss;
407 ss.print("'");
408 method->print_external_name(&ss);
409 ss.print("'");
410 THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(), ss.as_string());
411 }
412
413
414 address NativeLookup::lookup(const methodHandle& method, bool& in_base_library, TRAPS) {
415 if (!method->has_native_function()) {
416 address entry = lookup_base(method, in_base_library, CHECK_NULL);
417 method->set_native_function(entry,
418 Method::native_bind_event_is_interesting);
419 // -verbose:jni printing
420 if (log_is_enabled(Debug, jni, resolve)) {
421 ResourceMark rm(THREAD);
422 log_debug(jni, resolve)("[Dynamic-linking native method %s.%s ... JNI]",
423 method->method_holder()->external_name(),
424 method->name()->as_C_string());
425 }
426 }
427 return method->native_function();
428 }
429
430 address NativeLookup::base_library_lookup(const char* class_name, const char* method_name, const char* signature) {
431 EXCEPTION_MARK;
432 bool in_base_library = true; // SharedRuntime inits some math methods.
433 TempNewSymbol c_name = SymbolTable::new_symbol(class_name);
434 TempNewSymbol m_name = SymbolTable::new_symbol(method_name);
435 TempNewSymbol s_name = SymbolTable::new_symbol(signature);
436
437 // Find the class
438 Klass* k = SystemDictionary::resolve_or_fail(c_name, true, CATCH);
439 InstanceKlass* klass = InstanceKlass::cast(k);
440
441 // Find method and invoke standard lookup
442 methodHandle method (THREAD,
443 klass->uncached_lookup_method(m_name, s_name, Klass::OverpassLookupMode::find));
444 address result = lookup(method, in_base_library, CATCH);
445 assert(in_base_library, "must be in basic library");
446 guarantee(result != NULL, "must be non NULL");
447 return result;
448 }