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/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 #if INCLUDE_TRACE
140 { CC"Java_jdk_jfr_internal_JVM_registerNatives", NULL, TRACE_REGISTER_NATIVES },
141 #endif
142 };
143
144 static address lookup_special_native(char* jni_name) {
145 int count = sizeof(lookup_special_native_methods) / sizeof(JNINativeMethod);
146 for (int i = 0; i < count; i++) {
147 // NB: To ignore the jni prefix and jni postfix strstr is used matching.
148 if (strstr(jni_name, lookup_special_native_methods[i].name) != NULL) {
149 return CAST_FROM_FN_PTR(address, lookup_special_native_methods[i].fnPtr);
150 }
151 }
152 return NULL;
153 }
154
155 address NativeLookup::lookup_style(methodHandle method, char* pure_name, const char* long_name, int args_size, bool os_style, bool& in_base_library, TRAPS) {
156 address entry;
157 // Compute complete JNI name for style
158 stringStream st;
159 if (os_style) os::print_jni_name_prefix_on(&st, args_size);
160 st.print_raw(pure_name);
161 st.print_raw(long_name);
162 if (os_style) os::print_jni_name_suffix_on(&st, args_size);
163 char* jni_name = st.as_string();
164
165 // If the loader is null we have a system class, so we attempt a lookup in
166 // the native Java library. This takes care of any bootstrapping problems.
167 // Note: It is critical for bootstrapping that Java_java_lang_ClassLoader_00024NativeLibrary_find
168 // gets found the first time around - otherwise an infinite loop can occure. This is
169 // another VM/library dependency
170 Handle loader(THREAD, method->method_holder()->class_loader());
171 if (loader.is_null()) {
172 entry = lookup_special_native(jni_name);
173 if (entry == NULL) {
174 entry = (address) os::dll_lookup(os::native_java_library(), jni_name);
175 }
176 if (entry != NULL) {
177 in_base_library = true;
178 return entry;
179 }
180 }
181
182 // Otherwise call static method findNative in ClassLoader
183 KlassHandle klass (THREAD, SystemDictionary::ClassLoader_klass());
184 Handle name_arg = java_lang_String::create_from_str(jni_name, CHECK_NULL);
185
186 JavaValue result(T_LONG);
187 JavaCalls::call_static(&result,
188 klass,
189 vmSymbols::findNative_name(),
190 vmSymbols::classloader_string_long_signature(),
191 // Arguments
192 loader,
193 name_arg,
194 CHECK_NULL);
195 entry = (address) (intptr_t) result.get_jlong();
196
197 if (entry == NULL) {
198 // findNative didn't find it, if there are any agent libraries look in them
199 AgentLibrary* agent;
200 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
201 entry = (address) os::dll_lookup(agent->os_lib(), jni_name);
202 if (entry != NULL) {
203 return entry;
204 }
205 }
206 }
207
208 return entry;
209 }
210
211
212 address NativeLookup::lookup_critical_style(methodHandle method, char* pure_name, const char* long_name, int args_size, bool os_style) {
213 if (!method->has_native_function()) {
214 return NULL;
215 }
216
217 address current_entry = method->native_function();
218
219 char dll_name[JVM_MAXPATHLEN];
220 int offset;
221 if (os::dll_address_to_library_name(current_entry, dll_name, sizeof(dll_name), &offset)) {
222 char ebuf[32];
223 void* dll = os::dll_load(dll_name, ebuf, sizeof(ebuf));
224 if (dll != NULL) {
225 // Compute complete JNI name for style
226 stringStream st;
227 if (os_style) os::print_jni_name_prefix_on(&st, args_size);
228 st.print_raw(pure_name);
229 st.print_raw(long_name);
230 if (os_style) os::print_jni_name_suffix_on(&st, args_size);
231 char* jni_name = st.as_string();
232 return (address)os::dll_lookup(dll, jni_name);
233 }
234 }
235
236 return NULL;
237 }
238
239
240 // Check all the formats of native implementation name to see if there is one
241 // for the specified method.
242 address NativeLookup::lookup_entry(methodHandle method, bool& in_base_library, TRAPS) {
243 address entry = NULL;
244 in_base_library = false;
245 // Compute pure name
246 char* pure_name = pure_jni_name(method);
247
248 // Compute argument size
249 int args_size = 1 // JNIEnv
250 + (method->is_static() ? 1 : 0) // class for static methods
251 + method->size_of_parameters(); // actual parameters
252
253
254 // 1) Try JNI short style
255 entry = lookup_style(method, pure_name, "", args_size, true, in_base_library, CHECK_NULL);
256 if (entry != NULL) return entry;
257
258 // Compute long name
259 char* long_name = long_jni_name(method);
260
261 // 2) Try JNI long style
262 entry = lookup_style(method, pure_name, long_name, args_size, true, in_base_library, CHECK_NULL);
263 if (entry != NULL) return entry;
264
265 // 3) Try JNI short style without os prefix/suffix
266 entry = lookup_style(method, pure_name, "", args_size, false, in_base_library, CHECK_NULL);
267 if (entry != NULL) return entry;
268
269 // 4) Try JNI long style without os prefix/suffix
270 entry = lookup_style(method, pure_name, long_name, args_size, false, in_base_library, CHECK_NULL);
271
272 return entry; // NULL indicates not found
273 }
274
275 // Check all the formats of native implementation name to see if there is one
276 // for the specified method.
277 address NativeLookup::lookup_critical_entry(methodHandle method) {
278 if (!CriticalJNINatives) return NULL;
279
280 if (method->is_synchronized() ||
281 !method->is_static()) {
282 // Only static non-synchronized methods are allowed
283 return NULL;
284 }
285
286 ResourceMark rm;
287 address entry = NULL;
288
289 Symbol* signature = method->signature();
290 for (int end = 0; end < signature->utf8_length(); end++) {
291 if (signature->byte_at(end) == 'L') {
292 // Don't allow object types
293 return NULL;
294 }
295 }
296
297 // Compute critical name
298 char* critical_name = critical_jni_name(method);
299
300 // Compute argument size
301 int args_size = 1 // JNIEnv
302 + (method->is_static() ? 1 : 0) // class for static methods
303 + method->size_of_parameters(); // actual parameters
304
305
306 // 1) Try JNI short style
307 entry = lookup_critical_style(method, critical_name, "", args_size, true);
308 if (entry != NULL) return entry;
309
310 // Compute long name
311 char* long_name = long_jni_name(method);
312
313 // 2) Try JNI long style
314 entry = lookup_critical_style(method, critical_name, long_name, args_size, true);
315 if (entry != NULL) return entry;
316
317 // 3) Try JNI short style without os prefix/suffix
318 entry = lookup_critical_style(method, critical_name, "", args_size, false);
319 if (entry != NULL) return entry;
320
321 // 4) Try JNI long style without os prefix/suffix
322 entry = lookup_critical_style(method, critical_name, long_name, args_size, false);
323
324 return entry; // NULL indicates not found
325 }
326
327 // Check if there are any JVM TI prefixes which have been applied to the native method name.
328 // If any are found, remove them before attemping the look up of the
329 // native implementation again.
330 // See SetNativeMethodPrefix in the JVM TI Spec for more details.
331 address NativeLookup::lookup_entry_prefixed(methodHandle method, bool& in_base_library, TRAPS) {
332 #if INCLUDE_JVMTI
333 ResourceMark rm(THREAD);
334
335 int prefix_count;
336 char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
337 char* in_name = method->name()->as_C_string();
338 char* wrapper_name = in_name;
339 // last applied prefix will be first -- go backwards
340 for (int i = prefix_count-1; i >= 0; i--) {
341 char* prefix = prefixes[i];
342 size_t prefix_len = strlen(prefix);
343 if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
344 // has this prefix remove it
345 wrapper_name += prefix_len;
346 }
347 }
348 if (wrapper_name != in_name) {
349 // we have a name for a wrapping method
350 int wrapper_name_len = (int)strlen(wrapper_name);
351 TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);
352 if (wrapper_symbol != NULL) {
353 KlassHandle kh(method->method_holder());
354 Method* wrapper_method = kh()->lookup_method(wrapper_symbol,
355 method->signature());
356 if (wrapper_method != NULL && !wrapper_method->is_native()) {
357 // we found a wrapper method, use its native entry
358 method->set_is_prefixed_native();
359 return lookup_entry(wrapper_method, in_base_library, THREAD);
360 }
361 }
362 }
363 #endif // INCLUDE_JVMTI
364 return NULL;
365 }
366
367 address NativeLookup::lookup_base(methodHandle method, bool& in_base_library, TRAPS) {
368 address entry = NULL;
369 ResourceMark rm(THREAD);
370
371 entry = lookup_entry(method, in_base_library, THREAD);
372 if (entry != NULL) return entry;
373
374 // standard native method resolution has failed. Check if there are any
375 // JVM TI prefixes which have been applied to the native method name.
376 entry = lookup_entry_prefixed(method, in_base_library, THREAD);
377 if (entry != NULL) return entry;
378
379 // Native function not found, throw UnsatisfiedLinkError
380 THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(),
381 method->name_and_sig_as_C_string());
382 }
383
384
385 address NativeLookup::lookup(methodHandle method, bool& in_base_library, TRAPS) {
386 if (!method->has_native_function()) {
387 address entry = lookup_base(method, in_base_library, CHECK_NULL);
388 method->set_native_function(entry,
389 Method::native_bind_event_is_interesting);
390 // -verbose:jni printing
391 if (PrintJNIResolving) {
392 ResourceMark rm(THREAD);
393 tty->print_cr("[Dynamic-linking native method %s.%s ... JNI]",
394 method->method_holder()->external_name(),
395 method->name()->as_C_string());
396 }
397 }
398 return method->native_function();
399 }
400
401 address NativeLookup::base_library_lookup(const char* class_name, const char* method_name, const char* signature) {
402 EXCEPTION_MARK;
403 bool in_base_library = true; // SharedRuntime inits some math methods.
404 TempNewSymbol c_name = SymbolTable::new_symbol(class_name, CATCH);
405 TempNewSymbol m_name = SymbolTable::new_symbol(method_name, CATCH);
406 TempNewSymbol s_name = SymbolTable::new_symbol(signature, CATCH);
407
408 // Find the class
409 Klass* k = SystemDictionary::resolve_or_fail(c_name, true, CATCH);
410 instanceKlassHandle klass (THREAD, k);
411
412 // Find method and invoke standard lookup
413 methodHandle method (THREAD,
414 klass->uncached_lookup_method(m_name, s_name, Klass::find_overpass));
415 address result = lookup(method, in_base_library, CATCH);
416 assert(in_base_library, "must be in basic library");
417 guarantee(result != NULL, "must be non NULL");
418 return result;
419 }