libjava/stacktrace.cc

   1 // stacktrace.cc - Functions for unwinding & inspecting the call stack.
   2
   3 /* Copyright (C) 2005, 2006  Free Software Foundation
   4
   5    This file is part of libgcj.
   6
   7 This software is copyrighted work licensed under the terms of the
   8 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
   9 details.  */
  10
  11 #include <config.h>
  12 #include <platform.h>
  13
  14 #include <jvm.h>
  15 #include <gcj/cni.h>
  16 #include <java-interp.h>
  17 #include <java-stack.h>
  18
  19 #include <stdio.h>
  20
  21 #include <java/lang/Class.h>
  22 #include <java/lang/Long.h>
  23 #include <java/security/AccessController.h>
  24 #include <java/util/ArrayList.h>
  25 #include <java/util/IdentityHashMap.h>
  26 #include <gnu/java/lang/MainThread.h>
  27 #include <gnu/gcj/runtime/NameFinder.h>
  28 #include <gnu/gcj/runtime/StringBuffer.h>
  29
  30 #include <sysdep/backtrace.h>
  31 #include <sysdep/descriptor.h>
  32
  33 using namespace java::lang;
  34 using namespace java::lang::reflect;
  35 using namespace java::util;
  36 using namespace gnu::gcj::runtime;
  37
  38 // Maps ncode values to their containing native class.
  39 // NOTE: Currently this Map contradicts class GC for native classes. This map
  40 // (and the "new class stack") will need to use WeakReferences in order to
  41 // enable native class GC.
  42 static java::util::IdentityHashMap *ncodeMap;
  43
  44 // Check the "class stack" for any classes initialized since we were last
  45 // called, and add them to ncodeMap.
  46 void
  47 _Jv_StackTrace::UpdateNCodeMap ()
  48 {
  49   // The Map should be large enough so that a typical Java app doesn't cause
  50   // it to rehash, without using too much memory. ~5000 entries should be
  51   // enough.
  52   if (ncodeMap == NULL)
  53     ncodeMap = new java::util::IdentityHashMap (5087);
  54
  55   jclass klass;
  56   while ((klass = _Jv_PopClass ()))
  57     if (!_Jv_IsInterpretedClass (klass))
  58       {
  59         //printf ("got %s\n", klass->name->data);
  60         for (int i = 0; i < klass->method_count; i++)
  61           {
  62             _Jv_Method *method = &klass->methods[i];
  63             void *ncode = method->ncode;
  64             // Add non-abstract methods to ncodeMap.
  65             if (ncode)
  66               {
  67                 ncode = UNWRAP_FUNCTION_DESCRIPTOR (ncode);
  68                 ncodeMap->put ((java::lang::Object *) ncode, klass);
  69               }
  70           }
  71       }
  72 }
  73
  74 // Given a native frame, return the class which this code belongs
  75 // to. Returns NULL if this IP is not associated with a native Java class.
  76 // If NCODE is supplied, it will be set with the ip for the entry point of the
  77 // enclosing method.
  78 jclass
  79 _Jv_StackTrace::ClassForFrame (_Jv_StackFrame *frame)
  80 {
  81   JvAssert (frame->type == frame_native);
  82   jclass klass = NULL;
  83
  84   // look it up in ncodeMap
  85   if (frame->start_ip)
  86     klass = (jclass) ncodeMap->get ((jobject) frame->start_ip);
  87
  88   return klass;
  89 }
  90
  91 _Unwind_Reason_Code
  92 _Jv_StackTrace::UnwindTraceFn (struct _Unwind_Context *context, void *state_ptr)
  93 {
  94   _Jv_UnwindState *state = (_Jv_UnwindState *) state_ptr;
  95   jint pos = state->pos;
  96
  97   // Check if the trace buffer needs to be extended.
  98   if (pos == state->length)
  99     {
 100       int newLength = state->length * 2;
 101       void *newFrames = _Jv_AllocBytes (newLength * sizeof(_Jv_StackFrame));
 102       memcpy (newFrames, state->frames, state->length * sizeof(_Jv_StackFrame));
 103       state->frames = (_Jv_StackFrame *) newFrames;
 104       state->length = newLength;
 105     }
 106
 107   void *func_addr = (void *) _Unwind_GetRegionStart (context);
 108
 109   // If we see the interpreter's main function, "pop" an entry off the
 110   // interpreter stack and use that instead, so that the trace goes through
 111   // the java code and not the interpreter itself. This assumes a 1:1
 112   // correspondance between call frames in the interpreted stack and occurances
 113   // of _Jv_InterpMethod::run() on the native stack.
 114 #ifdef INTERPRETER
 115   void *interp_run = (void *) &_Jv_InterpMethod::run;
 116   if (func_addr == UNWRAP_FUNCTION_DESCRIPTOR (interp_run))
 117     {
 118       state->frames[pos].type = frame_interpreter;
 119       state->frames[pos].interp.meth = state->interp_frame->self;
 120       state->frames[pos].interp.pc = state->interp_frame->pc;
 121       state->interp_frame = state->interp_frame->next;
 122     }
 123   else
 124 #endif
 125     {
 126       _Unwind_Ptr ip;
 127       int ip_before_insn = 0;
 128       ip = _Unwind_GetIPInfo (context, &ip_before_insn);
 129
 130       // If the unwinder gave us a 'return' address, roll it back a little
 131       // to ensure we get the correct line number for the call itself.
 132       if (! ip_before_insn)
 133         --ip;
 134
 135       state->frames[pos].type = frame_native;
 136       state->frames[pos].ip = (void *) ip;
 137       state->frames[pos].start_ip = func_addr;
 138     }
 139
 140   _Unwind_Reason_Code result = _URC_NO_REASON;
 141   if (state->trace_function != NULL)
 142     result = (state->trace_function) (state);
 143   state->pos++;
 144   return result;
 145 }
 146
 147 // Return a raw stack trace from the current point of execution. The raw
 148 // trace will include all functions that have unwind info.
 149 _Jv_StackTrace *
 150 _Jv_StackTrace::GetStackTrace(void)
 151 {
 152   int trace_size = 100;
 153   _Jv_StackFrame frames[trace_size];
 154   _Jv_UnwindState state (trace_size);
 155   state.frames = (_Jv_StackFrame *) &frames;
 156
 157   _Unwind_Backtrace (UnwindTraceFn, &state);
 158
 159   // Copy the trace and return it.
 160   int traceSize = sizeof (_Jv_StackTrace) +
 161     (sizeof (_Jv_StackFrame) * state.pos);
 162   _Jv_StackTrace *trace = (_Jv_StackTrace *) _Jv_AllocBytes (traceSize);
 163   trace->length = state.pos;
 164   memcpy (trace->frames, state.frames, sizeof (_Jv_StackFrame) * state.pos);
 165   return trace;
 166 }
 167
 168 void
 169 _Jv_StackTrace::getLineNumberForFrame(_Jv_StackFrame *frame, NameFinder *finder,
 170                                       jstring *sourceFileName, jint *lineNum,
 171                                       jstring *methodName)
 172 {
 173 #ifdef INTERPRETER
 174   if (frame->type == frame_interpreter)
 175     {
 176       _Jv_InterpMethod *interp_meth = frame->interp.meth;
 177       _Jv_InterpClass *interp_class =
 178          (_Jv_InterpClass *) interp_meth->defining_class->aux_info;
 179       *sourceFileName = interp_class->source_file_name;
 180       // The interpreter advances the PC before executing an instruction,
 181       // so roll-back 1 byte to ensure the line number is accurate.
 182       *lineNum = interp_meth->get_source_line(frame->interp.pc - 1);
 183       return;
 184     }
 185 #endif
 186
 187   // Use _Jv_platform_dladdr() to determine in which binary the address IP
 188   // resides.
 189   _Jv_AddrInfo info;
 190   jstring binaryName = NULL;
 191   const char *argv0 = _Jv_GetSafeArg(0);
 192
 193   void *ip = frame->ip;
 194   _Unwind_Ptr offset = 0;
 195
 196   if (_Jv_platform_dladdr (ip, &info))
 197     {
 198       if (info.file_name)
 199         binaryName = JvNewStringUTF (info.file_name);
 200       else
 201         return;
 202
 203       if (*methodName == NULL && info.sym_name)
 204         *methodName = JvNewStringUTF (info.sym_name);
 205
 206       // addr2line expects relative addresses for shared libraries.
 207       if (strcmp (info.file_name, argv0) == 0)
 208         offset = (_Unwind_Ptr) ip;
 209       else
 210         offset = (_Unwind_Ptr) ip - (_Unwind_Ptr) info.base;
 211
 212       finder->lookup (binaryName, (jlong) offset);
 213       *sourceFileName = finder->getSourceFile();
 214       *lineNum = finder->getLineNum();
 215       if (*lineNum == -1 && NameFinder::showRaw())
 216         {
 217           gnu::gcj::runtime::StringBuffer *t =
 218             new gnu::gcj::runtime::StringBuffer(binaryName);
 219           t->append ((jchar)' ');
 220           t->append ((jchar)'[');
 221           // + 1 to compensate for the - 1 adjustment above;
 222           t->append (Long::toHexString (offset + 1));
 223           t->append ((jchar)']');
 224           *sourceFileName = t->toString();
 225         }
 226     }
 227 }
 228
 229 // Look up class and method info for the given stack frame, setting
 230 // frame->klass and frame->meth if they are known.
 231 void
 232 _Jv_StackTrace::FillInFrameInfo (_Jv_StackFrame *frame)
 233 {
 234   jclass klass = NULL;
 235   _Jv_Method *meth = NULL;
 236
 237   if (frame->type == frame_native)
 238     {
 239       klass = _Jv_StackTrace::ClassForFrame (frame);
 240
 241       if (klass != NULL)
 242         // Find method in class
 243         for (int j = 0; j < klass->method_count; j++)
 244           {
 245             void *wncode = UNWRAP_FUNCTION_DESCRIPTOR (klass->methods[j].ncode);
 246             if (wncode == frame->start_ip)
 247               {
 248                 meth = &klass->methods[j];
 249                 break;
 250               }
 251           }
 252     }
 253 #ifdef INTERPRETER
 254   else if (frame->type == frame_interpreter)
 255     {
 256       _Jv_InterpMethod *interp_meth = frame->interp.meth;
 257       klass = interp_meth->defining_class;
 258       meth = interp_meth->self;
 259     }
 260 #endif
 261   else
 262     JvFail ("Unknown frame type");
 263
 264   frame->klass = klass;
 265   frame->meth = meth;
 266 }
 267
 268 // Convert raw stack frames to a Java array of StackTraceElement objects.
 269 JArray< ::java::lang::StackTraceElement *>*
 270 _Jv_StackTrace::GetStackTraceElements (_Jv_StackTrace *trace,
 271   Throwable *throwable __attribute__((unused)))
 272 {
 273   ArrayList *list = new ArrayList ();
 274
 275 #if defined (SJLJ_EXCEPTIONS) && ! defined (WIN32)
 276   // We can't use the nCodeMap without unwinder support. Instead,
 277   // fake the method name by giving the IP in hex - better than nothing.
 278   jstring hex = JvNewStringUTF ("0x");
 279
 280   for (int i = 0; i < trace->length; i++)
 281     {
 282       jstring sourceFileName = NULL;
 283       jint lineNum = -1;
 284       _Jv_StackFrame *frame = &trace->frames[i];
 285
 286       jstring className = NULL;
 287       jstring methodName = hex->concat (Long::toHexString ((jlong) frame->ip));
 288
 289       StackTraceElement *element = new StackTraceElement (sourceFileName,
 290         lineNum, className, methodName, 0);
 291       list->add (element);
 292     }
 293
 294 #else /* SJLJ_EXCEPTIONS && !WIN32 */
 295
 296   //JvSynchronized (ncodeMap);
 297   UpdateNCodeMap ();
 298
 299   NameFinder *finder = new NameFinder();
 300   int start_idx = 0;
 301   int end_idx = trace->length - 1;
 302
 303   // First pass: strip superfluous frames from beginning and end of the trace.
 304   for (int i = 0; i < trace->length; i++)
 305     {
 306       _Jv_StackFrame *frame = &trace->frames[i];
 307       FillInFrameInfo (frame);
 308
 309       if (!frame->klass || !frame->meth)
 310         // Not a Java frame.
 311         continue;
 312
 313       // Throw away the top of the stack till we see:
 314       //  - the constructor(s) of this Throwable, or
 315       //  - the Throwable.fillInStackTrace call.
 316       if (frame->klass == throwable->getClass()
 317           && strcmp (frame->meth->name->chars(), "<init>") == 0)
 318         start_idx = i + 1;
 319
 320       if (frame->klass == &Throwable::class$
 321           && strcmp (frame->meth->name->chars(), "fillInStackTrace") == 0)
 322         start_idx = i + 1;
 323
 324       // End the trace at the application's main() method if we see call_main.
 325       if (frame->klass == &gnu::java::lang::MainThread::class$
 326           && strcmp (frame->meth->name->chars(), "call_main") == 0)
 327         end_idx = i - 1;
 328     }
 329
 330   const jboolean remove_unknown
 331     = gnu::gcj::runtime::NameFinder::removeUnknown();
 332
 333   // Second pass: Look up line-number info for remaining frames.
 334   for (int i = start_idx; i <= end_idx; i++)
 335     {
 336       _Jv_StackFrame *frame = &trace->frames[i];
 337
 338       if (frame->klass == NULL && remove_unknown)
 339         // Not a Java frame.
 340         continue;
 341
 342       jstring className = NULL;
 343       if (frame->klass != NULL)
 344         className = frame->klass->getName ();
 345
 346       jstring methodName = NULL;
 347       if (frame->meth)
 348         methodName = JvNewStringUTF (frame->meth->name->chars());
 349
 350       jstring sourceFileName = NULL;
 351       jint lineNum = -1;
 352
 353       getLineNumberForFrame(frame, finder, &sourceFileName, &lineNum,
 354                             &methodName);
 355
 356       StackTraceElement *element = new StackTraceElement (sourceFileName, lineNum,
 357         className, methodName, 0);
 358       list->add (element);
 359     }
 360
 361   finder->close();
 362 #endif /* SJLJ_EXCEPTIONS && !WIN32 */
 363
 364   JArray<Object *> *array = JvNewObjectArray (list->size (),
 365     &StackTraceElement::class$, NULL);
 366
 367   return (JArray<StackTraceElement *>*) list->toArray (array);
 368 }
 369
 370 struct CallingClassTraceData
 371 {
 372   jclass checkClass;
 373   jclass foundClass;
 374   _Jv_Method *foundMeth;
 375   bool seen_checkClass;
 376 };
 377
 378 _Unwind_Reason_Code
 379 _Jv_StackTrace::calling_class_trace_fn (_Jv_UnwindState *state)
 380 {
 381   CallingClassTraceData *trace_data = (CallingClassTraceData *)
 382     state->trace_data;
 383   _Jv_StackFrame *frame = &state->frames[state->pos];
 384   FillInFrameInfo (frame);
 385
 386   if (trace_data->seen_checkClass
 387       && frame->klass
 388       && frame->klass != trace_data->checkClass)
 389     {
 390       trace_data->foundClass = frame->klass;
 391       trace_data->foundMeth = frame->meth;
 392       return _URC_NORMAL_STOP;
 393     }
 394
 395   if (frame->klass == trace_data->checkClass)
 396     trace_data->seen_checkClass = true;
 397
 398   return _URC_NO_REASON;
 399 }
 400
 401 // Find the class immediately above the given class on the call stack. Any
 402 // intermediate non-Java
 403 // frames are ignored. If the calling class could not be determined (eg because
 404 // the unwinder is not supported on this platform), NULL is returned.
 405 // This function is used to implement calling-classloader checks and reflection
 406 // accessibility checks.
 407 // CHECKCLASS is typically the class calling GetCallingClass. The first class
 408 // above CHECKCLASS on the call stack will be returned.
 409 jclass
 410 _Jv_StackTrace::GetCallingClass (jclass checkClass)
 411 {
 412   jclass result = NULL;
 413   GetCallerInfo (checkClass, &result, NULL);
 414   return result;
 415 }
 416
 417 void
 418 _Jv_StackTrace::GetCallerInfo (jclass checkClass, jclass *caller_class,
 419   _Jv_Method **caller_meth)
 420 {
 421   int trace_size = 20;
 422   _Jv_StackFrame frames[trace_size];
 423   _Jv_UnwindState state (trace_size);
 424   state.frames = (_Jv_StackFrame *) &frames;
 425
 426   CallingClassTraceData trace_data;
 427   trace_data.checkClass = checkClass;
 428   trace_data.seen_checkClass = false;
 429   trace_data.foundClass = NULL;
 430   trace_data.foundMeth = NULL;
 431
 432   state.trace_function = calling_class_trace_fn;
 433   state.trace_data = (void *) &trace_data;
 434
 435   //JvSynchronized (ncodeMap);
 436   UpdateNCodeMap ();
 437
 438   _Unwind_Backtrace (UnwindTraceFn, &state);
 439
 440   if (caller_class)
 441     *caller_class = trace_data.foundClass;
 442   if (caller_meth)
 443     *caller_meth = trace_data.foundMeth;
 444 }
 445
 446 // Return a java array containing the Java classes on the stack above CHECKCLASS.
 447 JArray<jclass> *
 448 _Jv_StackTrace::GetClassContext (jclass checkClass)
 449 {
 450   JArray<jclass> *result = NULL;
 451
 452   int trace_size = 100;
 453   _Jv_StackFrame frames[trace_size];
 454   _Jv_UnwindState state (trace_size);
 455   state.frames = (_Jv_StackFrame *) &frames;
 456
 457   //JvSynchronized (ncodeMap);
 458   UpdateNCodeMap ();
 459
 460   _Unwind_Backtrace (UnwindTraceFn, &state);
 461
 462   // Count the number of Java frames on the stack.
 463   int jframe_count = 0;
 464   bool seen_checkClass = false;
 465   int start_pos = -1;
 466   for (int i = 0; i < state.pos; i++)
 467     {
 468       _Jv_StackFrame *frame = &state.frames[i];
 469       FillInFrameInfo (frame);
 470
 471       if (seen_checkClass)
 472         {
 473           if (frame->klass)
 474             {
 475               jframe_count++;
 476               if (start_pos == -1)
 477                 start_pos = i;
 478             }
 479         }
 480       else
 481         seen_checkClass = frame->klass == checkClass;
 482     }
 483   result = (JArray<jclass> *) _Jv_NewObjectArray (jframe_count, &Class::class$, NULL);
 484   int pos = 0;
 485
 486   for (int i = start_pos; i < state.pos; i++)
 487     {
 488       _Jv_StackFrame *frame = &state.frames[i];
 489       if (frame->klass)
 490         elements(result)[pos++] = frame->klass;
 491     }
 492   return result;
 493 }
 494
 495 _Unwind_Reason_Code
 496 _Jv_StackTrace::non_system_trace_fn (_Jv_UnwindState *state)
 497 {
 498   _Jv_StackFrame *frame = &state->frames[state->pos];
 499   FillInFrameInfo (frame);
 500
 501   ClassLoader *classLoader = NULL;
 502
 503   if (frame->klass)
 504     {
 505       classLoader = frame->klass->getClassLoaderInternal();
 506 #ifdef INTERPRETER
 507       if (classLoader != NULL)
 508         {
 509           state->trace_data = (void *) classLoader;
 510           return _URC_NORMAL_STOP;
 511         }
 512 #endif
 513     }
 514
 515   return _URC_NO_REASON;
 516 }
 517
 518 ClassLoader *
 519 _Jv_StackTrace::GetFirstNonSystemClassLoader ()
 520 {
 521   int trace_size = 32;
 522   _Jv_StackFrame frames[trace_size];
 523   _Jv_UnwindState state (trace_size);
 524   state.frames = (_Jv_StackFrame *) &frames;
 525   state.trace_function = non_system_trace_fn;
 526   state.trace_data = NULL;
 527
 528   //JvSynchronized (ncodeMap);
 529   UpdateNCodeMap ();
 530
 531   _Unwind_Backtrace (UnwindTraceFn, &state);
 532
 533   if (state.trace_data)
 534     return (ClassLoader *) state.trace_data;
 535
 536   return NULL;
 537 }
 538
 539 _Unwind_Reason_Code
 540 _Jv_StackTrace::accesscontrol_trace_fn (_Jv_UnwindState *state)
 541 {
 542   _Jv_StackFrame *frame = &state->frames[state->pos];
 543   FillInFrameInfo (frame);
 544
 545   if (!(frame->klass && frame->meth))
 546     return _URC_NO_REASON;
 547
 548   bool *stopping = (bool *) state->trace_data;
 549   if (*stopping)
 550     return _URC_NORMAL_STOP;
 551
 552   if (frame->klass == &::java::security::AccessController::class$
 553       && strcmp (frame->meth->name->chars(), "doPrivileged") == 0)
 554     *stopping = true;
 555
 556   return _URC_NO_REASON;
 557 }
 558
 559 JArray<jobjectArray> *
 560 _Jv_StackTrace::GetAccessControlStack (void)
 561 {
 562   int trace_size = 100;
 563   _Jv_StackFrame frames[trace_size];
 564   _Jv_UnwindState state (trace_size);
 565   state.frames = (_Jv_StackFrame *) &frames;
 566   state.trace_function = accesscontrol_trace_fn;
 567   bool stopping = false;
 568   state.trace_data = (void *) &stopping;
 569
 570   UpdateNCodeMap();
 571   _Unwind_Backtrace (UnwindTraceFn, &state);
 572
 573   jint length = 0;
 574
 575   for (int i = 0; i < state.pos; i++)
 576     {
 577       _Jv_StackFrame *frame = &state.frames[i];
 578
 579       if (frame->klass && frame->meth)
 580         length++;
 581     }
 582
 583   jclass array_class = _Jv_GetArrayClass (&::java::lang::Object::class$, NULL);
 584   JArray<jobjectArray> *result =
 585     (JArray<jobjectArray> *) _Jv_NewObjectArray (2, array_class, NULL);
 586   JArray<jclass> *classes = (JArray<jclass> *)
 587     _Jv_NewObjectArray (length, &::java::lang::Class::class$, NULL);
 588   JArray<jstring> *methods = (JArray<jstring> *)
 589     _Jv_NewObjectArray (length, &::java::lang::String::class$, NULL);
 590   jclass  *c = elements (classes);
 591   jstring *m = elements (methods);
 592
 593   for (int i = 0, j = 0; i < state.pos; i++)
 594     {
 595       _Jv_StackFrame *frame = &state.frames[i];
 596       if (!frame->klass || !frame->meth)
 597         continue;
 598       c[j] = frame->klass;
 599       m[j] = JvNewStringUTF (frame->meth->name->chars());
 600       j++;
 601     }
 602
 603   jobjectArray *elems = elements (result);
 604   elems[0] = (jobjectArray) classes;
 605   elems[1] = (jobjectArray) methods;
 606
 607   return result;
 608 }