1 /*
   2  * Copyright (c) 2015, 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/javaClasses.inline.hpp"
  28 #include "classfile/vmSymbols.hpp"
  29 #include "logging/log.hpp"
  30 #include "logging/logStream.hpp"
  31 #include "memory/oopFactory.hpp"
  32 #include "memory/universe.hpp"
  33 #include "oops/oop.inline.hpp"
  34 #include "oops/objArrayOop.inline.hpp"
  35 #include "prims/stackwalk.hpp"
  36 #include "runtime/globals.hpp"
  37 #include "runtime/handles.inline.hpp"
  38 #include "runtime/javaCalls.hpp"
  39 #include "runtime/thread.inline.hpp"
  40 #include "runtime/vframe.inline.hpp"
  41 #include "utilities/globalDefinitions.hpp"
  42 
  43 // setup and cleanup actions
  44 void BaseFrameStream::setup_magic_on_entry(objArrayHandle frames_array) {
  45   frames_array->obj_at_put(magic_pos, _thread->threadObj());
  46   _anchor = address_value();
  47   assert(check_magic(frames_array), "invalid magic");
  48 }
  49 
  50 bool BaseFrameStream::check_magic(objArrayHandle frames_array) {
  51   oop   m1 = frames_array->obj_at(magic_pos);
  52   jlong m2 = _anchor;
  53   if (oopDesc::equals(m1, _thread->threadObj()) && m2 == address_value())  return true;
  54   return false;
  55 }
  56 
  57 bool BaseFrameStream::cleanup_magic_on_exit(objArrayHandle frames_array) {
  58   bool ok = check_magic(frames_array);
  59   frames_array->obj_at_put(magic_pos, NULL);
  60   _anchor = 0L;
  61   return ok;
  62 }
  63 
  64 JavaFrameStream::JavaFrameStream(JavaThread* thread, int mode)
  65   : BaseFrameStream(thread), _vfst(thread) {
  66   _need_method_info = StackWalk::need_method_info(mode);
  67 }
  68 
  69 void JavaFrameStream::next() { _vfst.next();}
  70 
  71 // Returns the BaseFrameStream for the current stack being traversed.
  72 //
  73 // Parameters:
  74 //  thread         Current Java thread.
  75 //  magic          Magic value used for each stack walking
  76 //  frames_array   User-supplied buffers.  The 0th element is reserved
  77 //                 for this BaseFrameStream to use
  78 //
  79 BaseFrameStream* BaseFrameStream::from_current(JavaThread* thread, jlong magic,
  80                                                objArrayHandle frames_array)
  81 {
  82   assert(thread != NULL && thread->is_Java_thread(), "");
  83   oop m1 = frames_array->obj_at(magic_pos);
  84   if (!oopDesc::equals(m1, thread->threadObj())) return NULL;
  85   if (magic == 0L)                    return NULL;
  86   BaseFrameStream* stream = (BaseFrameStream*) (intptr_t) magic;
  87   if (!stream->is_valid_in(thread, frames_array))   return NULL;
  88   return stream;
  89 }
  90 
  91 // Unpacks one or more frames into user-supplied buffers.
  92 // Updates the end index, and returns the number of unpacked frames.
  93 // Always start with the existing vfst.method and bci.
  94 // Do not call vfst.next to advance over the last returned value.
  95 // In other words, do not leave any stale data in the vfst.
  96 //
  97 // Parameters:
  98 //   mode             Restrict which frames to be decoded.
  99 //   BaseFrameStream  stream of frames
 100 //   max_nframes      Maximum number of frames to be filled.
 101 //   start_index      Start index to the user-supplied buffers.
 102 //   frames_array     Buffer to store Class or StackFrame in, starting at start_index.
 103 //                    frames array is a Class<?>[] array when only getting caller
 104 //                    reference, and a StackFrameInfo[] array (or derivative)
 105 //                    otherwise. It should never be null.
 106 //   end_index        End index to the user-supplied buffers with unpacked frames.
 107 //
 108 // Returns the number of frames whose information was transferred into the buffers.
 109 //
 110 int StackWalk::fill_in_frames(jlong mode, BaseFrameStream& stream,
 111                               int max_nframes, int start_index,
 112                               objArrayHandle  frames_array,
 113                               int& end_index, TRAPS) {
 114   log_debug(stackwalk)("fill_in_frames limit=%d start=%d frames length=%d",
 115                        max_nframes, start_index, frames_array->length());
 116   assert(max_nframes > 0, "invalid max_nframes");
 117   assert(start_index + max_nframes <= frames_array->length(), "oob");
 118 
 119   int frames_decoded = 0;
 120   for (; !stream.at_end(); stream.next()) {
 121     Method* method = stream.method();
 122 
 123     if (method == NULL) continue;
 124 
 125     // skip hidden frames for default StackWalker option (i.e. SHOW_HIDDEN_FRAMES
 126     // not set) and when StackWalker::getCallerClass is called
 127     if (!ShowHiddenFrames && (skip_hidden_frames(mode) || get_caller_class(mode))) {
 128       if (method->is_hidden()) {
 129         LogTarget(Debug, stackwalk) lt;
 130         if (lt.is_enabled()) {
 131           ResourceMark rm(THREAD);
 132           LogStream ls(lt);
 133           ls.print("  hidden method: ");
 134           method->print_short_name(&ls);
 135           ls.cr();
 136         }
 137         continue;
 138       }
 139     }
 140 
 141     int index = end_index++;
 142     LogTarget(Debug, stackwalk) lt;
 143     if (lt.is_enabled()) {
 144       ResourceMark rm(THREAD);
 145       LogStream ls(lt);
 146       ls.print("  %d: frame method: ", index);
 147       method->print_short_name(&ls);
 148       ls.print_cr(" bci=%d", stream.bci());
 149     }
 150 
 151     if (!need_method_info(mode) && get_caller_class(mode) &&
 152           index == start_index && method->caller_sensitive()) {
 153       ResourceMark rm(THREAD);
 154       THROW_MSG_0(vmSymbols::java_lang_UnsupportedOperationException(),
 155         err_msg("StackWalker::getCallerClass called from @CallerSensitive '%s' method",
 156                 method->external_name()));
 157     }
 158     // fill in StackFrameInfo and initialize MemberName
 159     stream.fill_frame(index, frames_array, method, CHECK_0);
 160     if (++frames_decoded >= max_nframes)  break;
 161   }
 162   return frames_decoded;
 163 }
 164 
 165 // Fill in the LiveStackFrameInfo at the given index in frames_array
 166 void LiveFrameStream::fill_frame(int index, objArrayHandle  frames_array,
 167                                  const methodHandle& method, TRAPS) {
 168   HandleMark hm(THREAD);
 169   Handle stackFrame(THREAD, frames_array->obj_at(index));
 170   fill_live_stackframe(stackFrame, method, CHECK);
 171 }
 172 
 173 // Fill in the StackFrameInfo at the given index in frames_array
 174 void JavaFrameStream::fill_frame(int index, objArrayHandle  frames_array,
 175                                  const methodHandle& method, TRAPS) {
 176   if (_need_method_info) {
 177     HandleMark hm(THREAD);
 178     Handle stackFrame(THREAD, frames_array->obj_at(index));
 179     fill_stackframe(stackFrame, method, CHECK);
 180   } else {
 181     frames_array->obj_at_put(index, method->method_holder()->java_mirror());
 182   }
 183 }
 184 
 185 // Create and return a LiveStackFrame.PrimitiveSlot (if needed) for the
 186 // StackValue at the given index. 'type' is expected to be T_INT, T_LONG,
 187 // T_OBJECT, or T_CONFLICT.
 188 oop LiveFrameStream::create_primitive_slot_instance(StackValueCollection* values,
 189                                                     int i, BasicType type, TRAPS) {
 190   Klass* k = SystemDictionary::resolve_or_null(vmSymbols::java_lang_LiveStackFrameInfo(), CHECK_NULL);
 191   InstanceKlass* ik = InstanceKlass::cast(k);
 192 
 193   JavaValue result(T_OBJECT);
 194   JavaCallArguments args;
 195   Symbol* signature = NULL;
 196 
 197   // ## TODO: type is only available in LocalVariable table, if present.
 198   // ## StackValue type is T_INT or T_OBJECT (or converted to T_LONG on 64-bit)
 199   switch (type) {
 200     case T_INT:
 201       args.push_int(values->int_at(i));
 202       signature = vmSymbols::asPrimitive_int_signature();
 203       break;
 204 
 205     case T_LONG:
 206       args.push_long(values->long_at(i));
 207       signature = vmSymbols::asPrimitive_long_signature();
 208       break;
 209 
 210     case T_FLOAT:
 211     case T_DOUBLE:
 212     case T_BYTE:
 213     case T_SHORT:
 214     case T_CHAR:
 215     case T_BOOLEAN:
 216       THROW_MSG_(vmSymbols::java_lang_InternalError(), "Unexpected StackValue type", NULL);
 217 
 218     case T_OBJECT:
 219       return values->obj_at(i)();
 220 
 221     case T_CONFLICT:
 222       // put a non-null slot
 223       #ifdef _LP64
 224         args.push_long(0);
 225         signature = vmSymbols::asPrimitive_long_signature();
 226       #else
 227         args.push_int(0);
 228         signature = vmSymbols::asPrimitive_int_signature();
 229       #endif
 230 
 231       break;
 232 
 233     default: ShouldNotReachHere();
 234   }
 235   JavaCalls::call_static(&result,
 236                          ik,
 237                          vmSymbols::asPrimitive_name(),
 238                          signature,
 239                          &args,
 240                          CHECK_NULL);
 241   return (instanceOop) result.get_jobject();
 242 }
 243 
 244 objArrayHandle LiveFrameStream::values_to_object_array(StackValueCollection* values, TRAPS) {
 245   objArrayHandle empty;
 246   int length = values->size();
 247   objArrayOop array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(),
 248                                                    length, CHECK_(empty));
 249   objArrayHandle array_h(THREAD, array_oop);
 250   for (int i = 0; i < values->size(); i++) {
 251     StackValue* st = values->at(i);
 252     BasicType type = st->type();
 253     int index = i;
 254 #ifdef _LP64
 255     if (type != T_OBJECT && type != T_CONFLICT) {
 256         intptr_t ret = st->get_int(); // read full 64-bit slot
 257         type = T_LONG;                // treat as long
 258         index--;                      // undo +1 in StackValueCollection::long_at
 259     }
 260 #endif
 261     oop obj = create_primitive_slot_instance(values, index, type, CHECK_(empty));
 262     if (obj != NULL) {
 263       array_h->obj_at_put(i, obj);
 264     }
 265   }
 266   return array_h;
 267 }
 268 
 269 objArrayHandle LiveFrameStream::monitors_to_object_array(GrowableArray<MonitorInfo*>* monitors, TRAPS) {
 270   int length = monitors->length();
 271   objArrayOop array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(),
 272                                                    length, CHECK_(objArrayHandle()));
 273   objArrayHandle array_h(THREAD, array_oop);
 274   for (int i = 0; i < length; i++) {
 275     MonitorInfo* monitor = monitors->at(i);
 276     array_h->obj_at_put(i, monitor->owner());
 277   }
 278   return array_h;
 279 }
 280 
 281 // Fill StackFrameInfo with bci and initialize memberName
 282 void BaseFrameStream::fill_stackframe(Handle stackFrame, const methodHandle& method, TRAPS) {
 283   java_lang_StackFrameInfo::set_method_and_bci(stackFrame, method, bci(), THREAD);
 284 }
 285 
 286 // Fill LiveStackFrameInfo with locals, monitors, and expressions
 287 void LiveFrameStream::fill_live_stackframe(Handle stackFrame,
 288                                            const methodHandle& method, TRAPS) {
 289   fill_stackframe(stackFrame, method, CHECK);
 290   if (_jvf != NULL) {
 291     StackValueCollection* locals = _jvf->locals();
 292     StackValueCollection* expressions = _jvf->expressions();
 293     GrowableArray<MonitorInfo*>* monitors = _jvf->monitors();
 294 
 295     int mode = 0;
 296     if (_jvf->is_interpreted_frame()) {
 297       mode = MODE_INTERPRETED;
 298     } else if (_jvf->is_compiled_frame()) {
 299       mode = MODE_COMPILED;
 300     }
 301 
 302     if (!locals->is_empty()) {
 303       objArrayHandle locals_h = values_to_object_array(locals, CHECK);
 304       java_lang_LiveStackFrameInfo::set_locals(stackFrame(), locals_h());
 305     }
 306     if (!expressions->is_empty()) {
 307       objArrayHandle expressions_h = values_to_object_array(expressions, CHECK);
 308       java_lang_LiveStackFrameInfo::set_operands(stackFrame(), expressions_h());
 309     }
 310     if (monitors->length() > 0) {
 311       objArrayHandle monitors_h = monitors_to_object_array(monitors, CHECK);
 312       java_lang_LiveStackFrameInfo::set_monitors(stackFrame(), monitors_h());
 313     }
 314     java_lang_LiveStackFrameInfo::set_mode(stackFrame(), mode);
 315   }
 316 }
 317 
 318 // Begins stack walking.
 319 //
 320 // Parameters:
 321 //   stackStream    StackStream object
 322 //   mode           Stack walking mode.
 323 //   skip_frames    Number of frames to be skipped.
 324 //   frame_count    Number of frames to be traversed.
 325 //   start_index    Start index to the user-supplied buffers.
 326 //   frames_array   Buffer to store StackFrame in, starting at start_index.
 327 //                  frames array is a Class<?>[] array when only getting caller
 328 //                  reference, and a StackFrameInfo[] array (or derivative)
 329 //                  otherwise. It should never be null.
 330 //
 331 // Returns Object returned from AbstractStackWalker::doStackWalk call.
 332 //
 333 oop StackWalk::walk(Handle stackStream, jlong mode,
 334                     int skip_frames, int frame_count, int start_index,
 335                     objArrayHandle frames_array,
 336                     TRAPS) {
 337   ResourceMark rm(THREAD);
 338   JavaThread* jt = (JavaThread*)THREAD;
 339   log_debug(stackwalk)("Start walking: mode " JLONG_FORMAT " skip %d frames batch size %d",
 340                        mode, skip_frames, frame_count);
 341 
 342   if (frames_array.is_null()) {
 343     THROW_MSG_(vmSymbols::java_lang_NullPointerException(), "frames_array is NULL", NULL);
 344   }
 345 
 346   // Setup traversal onto my stack.
 347   if (live_frame_info(mode)) {
 348     assert (use_frames_array(mode), "Bad mode for get live frame");
 349     RegisterMap regMap(jt, true);
 350     LiveFrameStream stream(jt, &regMap);
 351     return fetchFirstBatch(stream, stackStream, mode, skip_frames, frame_count,
 352                            start_index, frames_array, THREAD);
 353   } else {
 354     JavaFrameStream stream(jt, mode);
 355     return fetchFirstBatch(stream, stackStream, mode, skip_frames, frame_count,
 356                            start_index, frames_array, THREAD);
 357   }
 358 }
 359 
 360 oop StackWalk::fetchFirstBatch(BaseFrameStream& stream, Handle stackStream,
 361                                jlong mode, int skip_frames, int frame_count,
 362                                int start_index, objArrayHandle frames_array, TRAPS) {
 363   methodHandle m_doStackWalk(THREAD, Universe::do_stack_walk_method());
 364 
 365   {
 366     Klass* stackWalker_klass = SystemDictionary::StackWalker_klass();
 367     Klass* abstractStackWalker_klass = SystemDictionary::AbstractStackWalker_klass();
 368     while (!stream.at_end()) {
 369       InstanceKlass* ik = stream.method()->method_holder();
 370       if (ik != stackWalker_klass &&
 371             ik != abstractStackWalker_klass && ik->super() != abstractStackWalker_klass)  {
 372         break;
 373       }
 374 
 375       LogTarget(Debug, stackwalk) lt;
 376       if (lt.is_enabled()) {
 377         ResourceMark rm(THREAD);
 378         LogStream ls(lt);
 379         ls.print("  skip ");
 380         stream.method()->print_short_name(&ls);
 381         ls.cr();
 382       }
 383       stream.next();
 384     }
 385 
 386     // stack frame has been traversed individually and resume stack walk
 387     // from the stack frame at depth == skip_frames.
 388     for (int n=0; n < skip_frames && !stream.at_end(); stream.next(), n++) {
 389       LogTarget(Debug, stackwalk) lt;
 390       if (lt.is_enabled()) {
 391         ResourceMark rm(THREAD);
 392         LogStream ls(lt);
 393         ls.print("  skip ");
 394         stream.method()->print_short_name(&ls);
 395         ls.cr();
 396       }
 397     }
 398   }
 399 
 400   int end_index = start_index;
 401   int numFrames = 0;
 402   if (!stream.at_end()) {
 403     numFrames = fill_in_frames(mode, stream, frame_count, start_index,
 404                                frames_array, end_index, CHECK_NULL);
 405     if (numFrames < 1) {
 406       THROW_MSG_(vmSymbols::java_lang_InternalError(), "stack walk: decode failed", NULL);
 407     }
 408   }
 409 
 410   // JVM_CallStackWalk walks the stack and fills in stack frames, then calls to
 411   // Java method java.lang.StackStreamFactory.AbstractStackWalker::doStackWalk
 412   // which calls the implementation to consume the stack frames.
 413   // When JVM_CallStackWalk returns, it invalidates the stack stream.
 414   JavaValue result(T_OBJECT);
 415   JavaCallArguments args(stackStream);
 416   args.push_long(stream.address_value());
 417   args.push_int(skip_frames);
 418   args.push_int(frame_count);
 419   args.push_int(start_index);
 420   args.push_int(end_index);
 421 
 422   // Link the thread and vframe stream into the callee-visible object
 423   stream.setup_magic_on_entry(frames_array);
 424 
 425   JavaCalls::call(&result, m_doStackWalk, &args, THREAD);
 426 
 427   // Do this before anything else happens, to disable any lingering stream objects
 428   bool ok = stream.cleanup_magic_on_exit(frames_array);
 429 
 430   // Throw pending exception if we must
 431   (void) (CHECK_NULL);
 432 
 433   if (!ok) {
 434     THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: corrupted buffers on exit", NULL);
 435   }
 436 
 437   // Return normally
 438   return (oop)result.get_jobject();
 439 }
 440 
 441 // Walk the next batch of stack frames
 442 //
 443 // Parameters:
 444 //   stackStream    StackStream object
 445 //   mode           Stack walking mode.
 446 //   magic          Must be valid value to continue the stack walk
 447 //   frame_count    Number of frames to be decoded.
 448 //   start_index    Start index to the user-supplied buffers.
 449 //   frames_array   Buffer to store StackFrame in, starting at start_index.
 450 //
 451 // Returns the end index of frame filled in the buffer.
 452 //
 453 jint StackWalk::fetchNextBatch(Handle stackStream, jlong mode, jlong magic,
 454                                int frame_count, int start_index,
 455                                objArrayHandle frames_array,
 456                                TRAPS)
 457 {
 458   JavaThread* jt = (JavaThread*)THREAD;
 459   BaseFrameStream* existing_stream = BaseFrameStream::from_current(jt, magic, frames_array);
 460   if (existing_stream == NULL) {
 461     THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: corrupted buffers", 0L);
 462   }
 463 
 464   if (frames_array.is_null()) {
 465     THROW_MSG_(vmSymbols::java_lang_NullPointerException(), "frames_array is NULL", 0L);
 466   }
 467 
 468   log_debug(stackwalk)("StackWalk::fetchNextBatch frame_count %d existing_stream "
 469                        PTR_FORMAT " start %d frames %d",
 470                        frame_count, p2i(existing_stream), start_index, frames_array->length());
 471   int end_index = start_index;
 472   if (frame_count <= 0) {
 473     return end_index;        // No operation.
 474   }
 475 
 476   int count = frame_count + start_index;
 477   assert (frames_array->length() >= count, "not enough space in buffers");
 478 
 479   BaseFrameStream& stream = (*existing_stream);
 480   if (!stream.at_end()) {
 481     stream.next(); // advance past the last frame decoded in previous batch
 482     if (!stream.at_end()) {
 483       int n = fill_in_frames(mode, stream, frame_count, start_index,
 484                              frames_array, end_index, CHECK_0);
 485       if (n < 1) {
 486         THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: later decode failed", 0L);
 487       }
 488       return end_index;
 489     }
 490   }
 491   return end_index;
 492 }
--- EOF ---