1/*
2 * Copyright (c) 1997, 2017, 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 "prims/unsafe.hpp"
39#include "runtime/arguments.hpp"
40#include "runtime/handles.inline.hpp"
41#include "runtime/javaCalls.hpp"
42#include "runtime/sharedRuntime.hpp"
43#include "runtime/signature.hpp"
44#include "utilities/macros.hpp"
45#if INCLUDE_TRACE
46#include "trace/traceMacros.hpp"
47#endif
48
49static void mangle_name_on(outputStream* st, Symbol* name, int begin, int end) {
50  char* bytes = (char*)name->bytes() + begin;
51  char* end_bytes = (char*)name->bytes() + end;
52  while (bytes < end_bytes) {
53    jchar c;
54    bytes = UTF8::next(bytes, &c);
55    if (c <= 0x7f && isalnum(c)) {
56      st->put((char) c);
57    } else {
58           if (c == '_') st->print("_1");
59      else if (c == '/') st->print("_");
60      else if (c == ';') st->print("_2");
61      else if (c == '[') st->print("_3");
62      else               st->print("_%.5x", c);
63    }
64  }
65}
66
67
68static void mangle_name_on(outputStream* st, Symbol* name) {
69  mangle_name_on(st, name, 0, name->utf8_length());
70}
71
72
73char* NativeLookup::pure_jni_name(const methodHandle& method) {
74  stringStream st;
75  // Prefix
76  st.print("Java_");
77  // Klass name
78  mangle_name_on(&st, method->klass_name());
79  st.print("_");
80  // Method name
81  mangle_name_on(&st, method->name());
82  return st.as_string();
83}
84
85
86char* NativeLookup::critical_jni_name(const methodHandle& method) {
87  stringStream st;
88  // Prefix
89  st.print("JavaCritical_");
90  // Klass name
91  mangle_name_on(&st, method->klass_name());
92  st.print("_");
93  // Method name
94  mangle_name_on(&st, method->name());
95  return st.as_string();
96}
97
98
99char* NativeLookup::long_jni_name(const methodHandle& method) {
100  // Signature ignore the wrapping parenteses and the trailing return type
101  stringStream st;
102  Symbol* signature = method->signature();
103  st.print("__");
104  // find ')'
105  int end;
106  for (end = 0; end < signature->utf8_length() && signature->byte_at(end) != ')'; end++);
107  // skip first '('
108  mangle_name_on(&st, signature, 1, end);
109  return st.as_string();
110}
111
112extern "C" {
113  void JNICALL JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass unsafecls);
114  void JNICALL JVM_RegisterPerfMethods(JNIEnv *env, jclass perfclass);
115  void JNICALL JVM_RegisterWhiteBoxMethods(JNIEnv *env, jclass wbclass);
116#if INCLUDE_JVMCI
117  jobject  JNICALL JVM_GetJVMCIRuntime(JNIEnv *env, jclass c);
118  void     JNICALL JVM_RegisterJVMCINatives(JNIEnv *env, jclass compilerToVMClass);
119#endif
120}
121
122#define CC (char*)  /* cast a literal from (const char*) */
123#define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
124
125static JNINativeMethod lookup_special_native_methods[] = {
126  { CC"Java_jdk_internal_misc_Unsafe_registerNatives",             NULL, FN_PTR(JVM_RegisterJDKInternalMiscUnsafeMethods) },
127  { CC"Java_java_lang_invoke_MethodHandleNatives_registerNatives", NULL, FN_PTR(JVM_RegisterMethodHandleMethods) },
128  { CC"Java_jdk_internal_perf_Perf_registerNatives",               NULL, FN_PTR(JVM_RegisterPerfMethods)         },
129  { CC"Java_sun_hotspot_WhiteBox_registerNatives",                 NULL, FN_PTR(JVM_RegisterWhiteBoxMethods)     },
130#if INCLUDE_JVMCI
131  { CC"Java_jdk_vm_ci_runtime_JVMCI_initializeRuntime",            NULL, FN_PTR(JVM_GetJVMCIRuntime)             },
132  { CC"Java_jdk_vm_ci_hotspot_CompilerToVM_registerNatives",       NULL, FN_PTR(JVM_RegisterJVMCINatives)        },
133#endif
134#if INCLUDE_TRACE
135  { CC"Java_jdk_jfr_internal_JVM_registerNatives",                 NULL, TRACE_REGISTER_NATIVES                  },
136#endif
137};
138
139static address lookup_special_native(char* jni_name) {
140  int count = sizeof(lookup_special_native_methods) / sizeof(JNINativeMethod);
141  for (int i = 0; i < count; i++) {
142    // NB: To ignore the jni prefix and jni postfix strstr is used matching.
143    if (strstr(jni_name, lookup_special_native_methods[i].name) != NULL) {
144      return CAST_FROM_FN_PTR(address, lookup_special_native_methods[i].fnPtr);
145    }
146  }
147  return NULL;
148}
149
150address NativeLookup::lookup_style(const methodHandle& method, char* pure_name, const char* long_name, int args_size, bool os_style, bool& in_base_library, TRAPS) {
151  address entry;
152  // Compute complete JNI name for style
153  stringStream st;
154  if (os_style) os::print_jni_name_prefix_on(&st, args_size);
155  st.print_raw(pure_name);
156  st.print_raw(long_name);
157  if (os_style) os::print_jni_name_suffix_on(&st, args_size);
158  char* jni_name = st.as_string();
159
160  // If the loader is null we have a system class, so we attempt a lookup in
161  // the native Java library. This takes care of any bootstrapping problems.
162  // Note: It is critical for bootstrapping that Java_java_lang_ClassLoader_00024NativeLibrary_find
163  // gets found the first time around - otherwise an infinite loop can occure. This is
164  // another VM/library dependency
165  Handle loader(THREAD, method->method_holder()->class_loader());
166  if (loader.is_null()) {
167    entry = lookup_special_native(jni_name);
168    if (entry == NULL) {
169       entry = (address) os::dll_lookup(os::native_java_library(), jni_name);
170    }
171    if (entry != NULL) {
172      in_base_library = true;
173      return entry;
174    }
175  }
176
177  // Otherwise call static method findNative in ClassLoader
178  Klass*   klass = SystemDictionary::ClassLoader_klass();
179  Handle name_arg = java_lang_String::create_from_str(jni_name, CHECK_NULL);
180
181  JavaValue result(T_LONG);
182  JavaCalls::call_static(&result,
183                         klass,
184                         vmSymbols::findNative_name(),
185                         vmSymbols::classloader_string_long_signature(),
186                         // Arguments
187                         loader,
188                         name_arg,
189                         CHECK_NULL);
190  entry = (address) (intptr_t) result.get_jlong();
191
192  if (entry == NULL) {
193    // findNative didn't find it, if there are any agent libraries look in them
194    AgentLibrary* agent;
195    for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
196      entry = (address) os::dll_lookup(agent->os_lib(), jni_name);
197      if (entry != NULL) {
198        return entry;
199      }
200    }
201  }
202
203  return entry;
204}
205
206
207address NativeLookup::lookup_critical_style(const methodHandle& method, char* pure_name, const char* long_name, int args_size, bool os_style) {
208  if (!method->has_native_function()) {
209    return NULL;
210  }
211
212  address current_entry = method->native_function();
213
214  char dll_name[JVM_MAXPATHLEN];
215  int offset;
216  if (os::dll_address_to_library_name(current_entry, dll_name, sizeof(dll_name), &offset)) {
217    char ebuf[32];
218    void* dll = os::dll_load(dll_name, ebuf, sizeof(ebuf));
219    if (dll != NULL) {
220      // Compute complete JNI name for style
221      stringStream st;
222      if (os_style) os::print_jni_name_prefix_on(&st, args_size);
223      st.print_raw(pure_name);
224      st.print_raw(long_name);
225      if (os_style) os::print_jni_name_suffix_on(&st, args_size);
226      char* jni_name = st.as_string();
227      return (address)os::dll_lookup(dll, jni_name);
228    }
229  }
230
231  return NULL;
232}
233
234
235// Check all the formats of native implementation name to see if there is one
236// for the specified method.
237address NativeLookup::lookup_entry(const methodHandle& method, bool& in_base_library, TRAPS) {
238  address entry = NULL;
239  in_base_library = false;
240  // Compute pure name
241  char* pure_name = pure_jni_name(method);
242
243  // Compute argument size
244  int args_size = 1                             // JNIEnv
245                + (method->is_static() ? 1 : 0) // class for static methods
246                + method->size_of_parameters(); // actual parameters
247
248
249  // 1) Try JNI short style
250  entry = lookup_style(method, pure_name, "",        args_size, true,  in_base_library, CHECK_NULL);
251  if (entry != NULL) return entry;
252
253  // Compute long name
254  char* long_name = long_jni_name(method);
255
256  // 2) Try JNI long style
257  entry = lookup_style(method, pure_name, long_name, args_size, true,  in_base_library, CHECK_NULL);
258  if (entry != NULL) return entry;
259
260  // 3) Try JNI short style without os prefix/suffix
261  entry = lookup_style(method, pure_name, "",        args_size, false, in_base_library, CHECK_NULL);
262  if (entry != NULL) return entry;
263
264  // 4) Try JNI long style without os prefix/suffix
265  entry = lookup_style(method, pure_name, long_name, args_size, false, in_base_library, CHECK_NULL);
266
267  return entry; // NULL indicates not found
268}
269
270// Check all the formats of native implementation name to see if there is one
271// for the specified method.
272address NativeLookup::lookup_critical_entry(const methodHandle& method) {
273  if (!CriticalJNINatives) return NULL;
274
275  if (method->is_synchronized() ||
276      !method->is_static()) {
277    // Only static non-synchronized methods are allowed
278    return NULL;
279  }
280
281  ResourceMark rm;
282  address entry = NULL;
283
284  Symbol* signature = method->signature();
285  for (int end = 0; end < signature->utf8_length(); end++) {
286    if (signature->byte_at(end) == 'L') {
287      // Don't allow object types
288      return NULL;
289    }
290  }
291
292  // Compute critical name
293  char* critical_name = critical_jni_name(method);
294
295  // Compute argument size
296  int args_size = 1                             // JNIEnv
297                + (method->is_static() ? 1 : 0) // class for static methods
298                + method->size_of_parameters(); // actual parameters
299
300
301  // 1) Try JNI short style
302  entry = lookup_critical_style(method, critical_name, "",        args_size, true);
303  if (entry != NULL) return entry;
304
305  // Compute long name
306  char* long_name = long_jni_name(method);
307
308  // 2) Try JNI long style
309  entry = lookup_critical_style(method, critical_name, long_name, args_size, true);
310  if (entry != NULL) return entry;
311
312  // 3) Try JNI short style without os prefix/suffix
313  entry = lookup_critical_style(method, critical_name, "",        args_size, false);
314  if (entry != NULL) return entry;
315
316  // 4) Try JNI long style without os prefix/suffix
317  entry = lookup_critical_style(method, critical_name, long_name, args_size, false);
318
319  return entry; // NULL indicates not found
320}
321
322// Check if there are any JVM TI prefixes which have been applied to the native method name.
323// If any are found, remove them before attemping the look up of the
324// native implementation again.
325// See SetNativeMethodPrefix in the JVM TI Spec for more details.
326address NativeLookup::lookup_entry_prefixed(const methodHandle& method, bool& in_base_library, TRAPS) {
327#if INCLUDE_JVMTI
328  ResourceMark rm(THREAD);
329
330  int prefix_count;
331  char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
332  char* in_name = method->name()->as_C_string();
333  char* wrapper_name = in_name;
334  // last applied prefix will be first -- go backwards
335  for (int i = prefix_count-1; i >= 0; i--) {
336    char* prefix = prefixes[i];
337    size_t prefix_len = strlen(prefix);
338    if (strncmp(prefix, wrapper_name, prefix_len) == 0) {
339      // has this prefix remove it
340      wrapper_name += prefix_len;
341    }
342  }
343  if (wrapper_name != in_name) {
344    // we have a name for a wrapping method
345    int wrapper_name_len = (int)strlen(wrapper_name);
346    TempNewSymbol wrapper_symbol = SymbolTable::probe(wrapper_name, wrapper_name_len);
347    if (wrapper_symbol != NULL) {
348      Klass* k = method->method_holder();
349      Method* wrapper_method = k->lookup_method(wrapper_symbol, method->signature());
350      if (wrapper_method != NULL && !wrapper_method->is_native()) {
351        // we found a wrapper method, use its native entry
352        method->set_is_prefixed_native();
353        return lookup_entry(wrapper_method, in_base_library, THREAD);
354      }
355    }
356  }
357#endif // INCLUDE_JVMTI
358  return NULL;
359}
360
361address NativeLookup::lookup_base(const methodHandle& method, bool& in_base_library, TRAPS) {
362  address entry = NULL;
363  ResourceMark rm(THREAD);
364
365  entry = lookup_entry(method, in_base_library, THREAD);
366  if (entry != NULL) return entry;
367
368  // standard native method resolution has failed.  Check if there are any
369  // JVM TI prefixes which have been applied to the native method name.
370  entry = lookup_entry_prefixed(method, in_base_library, THREAD);
371  if (entry != NULL) return entry;
372
373  // Native function not found, throw UnsatisfiedLinkError
374  THROW_MSG_0(vmSymbols::java_lang_UnsatisfiedLinkError(),
375              method->name_and_sig_as_C_string());
376}
377
378
379address NativeLookup::lookup(const methodHandle& method, bool& in_base_library, TRAPS) {
380  if (!method->has_native_function()) {
381    address entry = lookup_base(method, in_base_library, CHECK_NULL);
382    method->set_native_function(entry,
383      Method::native_bind_event_is_interesting);
384    // -verbose:jni printing
385    if (PrintJNIResolving) {
386      ResourceMark rm(THREAD);
387      tty->print_cr("[Dynamic-linking native method %s.%s ... JNI]",
388        method->method_holder()->external_name(),
389        method->name()->as_C_string());
390    }
391  }
392  return method->native_function();
393}
394
395address NativeLookup::base_library_lookup(const char* class_name, const char* method_name, const char* signature) {
396  EXCEPTION_MARK;
397  bool in_base_library = true;  // SharedRuntime inits some math methods.
398  TempNewSymbol c_name = SymbolTable::new_symbol(class_name,  CATCH);
399  TempNewSymbol m_name = SymbolTable::new_symbol(method_name, CATCH);
400  TempNewSymbol s_name = SymbolTable::new_symbol(signature,   CATCH);
401
402  // Find the class
403  Klass* k = SystemDictionary::resolve_or_fail(c_name, true, CATCH);
404  InstanceKlass* klass  = InstanceKlass::cast(k);
405
406  // Find method and invoke standard lookup
407  methodHandle method (THREAD,
408                       klass->uncached_lookup_method(m_name, s_name, Klass::find_overpass));
409  address result = lookup(method, in_base_library, CATCH);
410  assert(in_base_library, "must be in basic library");
411  guarantee(result != NULL, "must be non NULL");
412  return result;
413}
414