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
51static 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
70static void mangle_name_on(outputStream* st, Symbol* name) {
71 mangle_name_on(st, name, 0, name->utf8_length());
72}
73
74
75char* 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
88char* 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
101char* 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
114extern "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
127static 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
141static 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
152address 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
209address 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.
245address 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.
279address 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.
335address 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
370address 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
391address 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
407address 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}
426