1 /*
   2  * Copyright (c) 2015, 2016, 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 "memory/oopFactory.hpp"
  30 #include "oops/oop.inline.hpp"
  31 #include "oops/objArrayOop.inline.hpp"
  32 #include "prims/stackwalk.hpp"
  33 #include "runtime/globals.hpp"
  34 #include "runtime/handles.inline.hpp"
  35 #include "runtime/javaCalls.hpp"
  36 #include "runtime/vframe.hpp"
  37 #include "utilities/globalDefinitions.hpp"
  38 
  39 // setup and cleanup actions
  40 void JavaFrameStream::setup_magic_on_entry(objArrayHandle frames_array) {
  41   frames_array->obj_at_put(magic_pos, _thread->threadObj());
  42   _anchor = address_value();
  43   assert(check_magic(frames_array), "invalid magic");
  44 }
  45 
  46 bool JavaFrameStream::check_magic(objArrayHandle frames_array) {
  47   oop   m1 = frames_array->obj_at(magic_pos);
  48   jlong m2 = _anchor;
  49   if (m1 == _thread->threadObj() && m2 == address_value())  return true;
  50   return false;
  51 }
  52 
  53 bool JavaFrameStream::cleanup_magic_on_exit(objArrayHandle frames_array) {
  54   bool ok = check_magic(frames_array);
  55   frames_array->obj_at_put(magic_pos, NULL);
  56   _anchor = 0L;
  57   return ok;
  58 }
  59 
  60 // Returns JavaFrameStream for the current stack being traversed.
  61 //
  62 // Parameters:
  63 //  thread         Current Java thread.
  64 //  magic          Magic value used for each stack walking
  65 //  frames_array   User-supplied buffers.  The 0th element is reserved
  66 //                 to this JavaFrameStream to use
  67 //
  68 JavaFrameStream* JavaFrameStream::from_current(JavaThread* thread, jlong magic,
  69                                                objArrayHandle frames_array)
  70 {
  71   assert(thread != NULL && thread->is_Java_thread(), "");
  72   oop m1 = frames_array->obj_at(magic_pos);
  73   if (m1 != thread->threadObj())      return NULL;
  74   if (magic == 0L)                    return NULL;
  75   JavaFrameStream* stream = (JavaFrameStream*) (intptr_t) magic;
  76   if (!stream->is_valid_in(thread, frames_array))   return NULL;
  77   return stream;
  78 }
  79 
  80 // Unpacks one or more frames into user-supplied buffers.
  81 // Updates the end index, and returns the number of unpacked frames.
  82 // Always start with the existing vfst.method and bci.
  83 // Do not call vfst.next to advance over the last returned value.
  84 // In other words, do not leave any stale data in the vfst.
  85 //
  86 // Parameters:
  87 //   mode             Restrict which frames to be decoded.
  88 //   JavaFrameStream  stream of javaVFrames
  89 //   max_nframes      Maximum number of frames to be filled.
  90 //   start_index      Start index to the user-supplied buffers.
  91 //   frames_array     Buffer to store Class or StackFrame in, starting at start_index.
  92 //                    frames array is a Class<?>[] array when only getting caller
  93 //                    reference, and a StackFrameInfo[] array (or derivative)
  94 //                    otherwise. It should never be null.
  95 //   end_index        End index to the user-supplied buffers with unpacked frames.
  96 //
  97 // Returns the number of frames whose information was transferred into the buffers.
  98 //
  99 int StackWalk::fill_in_frames(jlong mode, JavaFrameStream& stream,
 100                               int max_nframes, int start_index,
 101                               objArrayHandle  frames_array,
 102                               int& end_index, TRAPS) {
 103   if (TraceStackWalk) {
 104     tty->print_cr("fill_in_frames limit=%d start=%d frames length=%d",
 105                   max_nframes, start_index, frames_array->length());
 106   }
 107   assert(max_nframes > 0, "invalid max_nframes");
 108   assert(start_index + max_nframes <= frames_array->length(), "oob");
 109 
 110   int frames_decoded = 0;
 111   for (; !stream.at_end(); stream.next()) {
 112     Method* method = stream.method();
 113     int bci = stream.bci();
 114 
 115     if (method == NULL) continue;
 116 
 117     // skip hidden frames for default StackWalker option (i.e. SHOW_HIDDEN_FRAMES
 118     // not set) and when StackWalker::getCallerClass is called
 119     if (!ShowHiddenFrames && (skip_hidden_frames(mode) || get_caller_class(mode))) {
 120       if (method->is_hidden()) {
 121         if (TraceStackWalk) {
 122           tty->print("  hidden method: "); method->print_short_name();
 123           tty->print("\n");
 124         }
 125         continue;
 126       }
 127     }
 128 
 129     int index = end_index++;
 130     if (TraceStackWalk) {
 131       tty->print("  %d: frame method: ", index); method->print_short_name();
 132       tty->print_cr(" bci=%d", bci);
 133     }
 134 
 135     // fill in StackFrameInfo and initialize MemberName
 136     if (live_frame_info(mode)) {
 137       assert (use_frames_array(mode), "Bad mode for get live frame");
 138       Handle stackFrame(frames_array->obj_at(index));
 139       fill_live_stackframe(stackFrame, method, bci, stream.java_frame(), CHECK_0);
 140     } else if (need_method_info(mode)) {
 141       assert (use_frames_array(mode), "Bad mode for get stack frame");
 142       Handle stackFrame(frames_array->obj_at(index));
 143       fill_stackframe(stackFrame, method, bci);
 144     } else {
 145       assert (use_frames_array(mode) == false, "Bad mode for filling in Class object");
 146       if (get_caller_class(mode) && index == start_index && method->caller_sensitive()) {
 147         ResourceMark rm(THREAD);
 148         THROW_MSG_0(vmSymbols::java_lang_UnsupportedOperationException(),
 149           err_msg("StackWalker::getCallerClass called from @CallerSensitive %s method",
 150                   method->name_and_sig_as_C_string()));
 151       }
 152 
 153       frames_array->obj_at_put(index, method->method_holder()->java_mirror());
 154     }
 155     if (++frames_decoded >= max_nframes)  break;
 156   }
 157   return frames_decoded;
 158 }
 159 
 160 static oop create_primitive_value_instance(StackValueCollection* values, int i, TRAPS) {
 161   Klass* k = SystemDictionary::resolve_or_null(vmSymbols::java_lang_LiveStackFrameInfo(), CHECK_NULL);
 162   instanceKlassHandle ik (THREAD, k);
 163 
 164   JavaValue result(T_OBJECT);
 165   JavaCallArguments args;
 166   Symbol* signature = NULL;
 167 
 168   // ## TODO: type is only available in LocalVariable table, if present.
 169   // ## StackValue type is T_INT or T_OBJECT.
 170   switch (values->at(i)->type()) {
 171     case T_INT:
 172       args.push_int(values->int_at(i));
 173       signature = vmSymbols::asPrimitive_int_signature();
 174       break;
 175 
 176     case T_LONG:
 177       args.push_long(values->long_at(i));
 178       signature = vmSymbols::asPrimitive_long_signature();
 179       break;
 180 
 181     case T_FLOAT:
 182       args.push_float(values->float_at(i));
 183       signature = vmSymbols::asPrimitive_float_signature();
 184       break;
 185 
 186     case T_DOUBLE:
 187       args.push_double(values->double_at(i));
 188       signature = vmSymbols::asPrimitive_double_signature();
 189       break;
 190 
 191     case T_BYTE:
 192       args.push_int(values->int_at(i));
 193       signature = vmSymbols::asPrimitive_byte_signature();
 194       break;
 195 
 196     case T_SHORT:
 197       args.push_int(values->int_at(i));
 198       signature = vmSymbols::asPrimitive_short_signature();
 199       break;
 200 
 201     case T_CHAR:
 202       args.push_int(values->int_at(i));
 203       signature = vmSymbols::asPrimitive_char_signature();
 204       break;
 205 
 206     case T_BOOLEAN:
 207       args.push_int(values->int_at(i));
 208       signature = vmSymbols::asPrimitive_boolean_signature();
 209       break;
 210 
 211     case T_OBJECT:
 212       return values->obj_at(i)();
 213 
 214     case T_CONFLICT:
 215       // put a non-null slot
 216       args.push_int(0);
 217       signature = vmSymbols::asPrimitive_int_signature();
 218       break;
 219 
 220     default: ShouldNotReachHere();
 221   }
 222   JavaCalls::call_static(&result,
 223                          ik,
 224                          vmSymbols::asPrimitive_name(),
 225                          signature,
 226                          &args,
 227                          CHECK_NULL);
 228   return (instanceOop) result.get_jobject();
 229 }
 230 
 231 static objArrayHandle values_to_object_array(StackValueCollection* values, TRAPS) {
 232   objArrayHandle empty;
 233   int length = values->size();
 234   objArrayOop array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(),
 235                                                    length, CHECK_(empty));
 236   objArrayHandle array_h(THREAD, array_oop);
 237   for (int i = 0; i < values->size(); i++) {
 238     StackValue* st = values->at(i);
 239     oop obj = create_primitive_value_instance(values, i, CHECK_(empty));
 240     if (obj != NULL)
 241       array_h->obj_at_put(i, obj);
 242   }
 243   return array_h;
 244 }
 245 
 246 static objArrayHandle monitors_to_object_array(GrowableArray<MonitorInfo*>* monitors, TRAPS) {
 247   int length = monitors->length();
 248   objArrayOop array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(),
 249                                                    length, CHECK_(objArrayHandle()));
 250   objArrayHandle array_h(THREAD, array_oop);
 251   for (int i = 0; i < length; i++) {
 252     MonitorInfo* monitor = monitors->at(i);
 253     array_h->obj_at_put(i, monitor->owner());
 254   }
 255   return array_h;
 256 }
 257 
 258 // Fill StackFrameInfo with declaringClass and bci and initialize memberName
 259 void StackWalk::fill_stackframe(Handle stackFrame, const methodHandle& method, int bci) {
 260   java_lang_StackFrameInfo::set_declaringClass(stackFrame(), method->method_holder()->java_mirror());
 261   java_lang_StackFrameInfo::set_method_and_bci(stackFrame(), method, bci);
 262 }
 263 
 264 // Fill LiveStackFrameInfo with locals, monitors, and expressions
 265 void StackWalk::fill_live_stackframe(Handle stackFrame, const methodHandle& method,
 266                                      int bci, javaVFrame* jvf, TRAPS) {
 267   fill_stackframe(stackFrame, method, bci);
 268   if (jvf != NULL) {
 269     StackValueCollection* locals = jvf->locals();
 270     StackValueCollection* expressions = jvf->expressions();
 271     GrowableArray<MonitorInfo*>* monitors = jvf->monitors();
 272 
 273     if (!locals->is_empty()) {
 274       objArrayHandle locals_h = values_to_object_array(locals, CHECK);
 275       java_lang_LiveStackFrameInfo::set_locals(stackFrame(), locals_h());
 276     }
 277     if (!expressions->is_empty()) {
 278       objArrayHandle expressions_h = values_to_object_array(expressions, CHECK);
 279       java_lang_LiveStackFrameInfo::set_operands(stackFrame(), expressions_h());
 280     }
 281     if (monitors->length() > 0) {
 282       objArrayHandle monitors_h = monitors_to_object_array(monitors, CHECK);
 283       java_lang_LiveStackFrameInfo::set_monitors(stackFrame(), monitors_h());
 284     }
 285   }
 286 }
 287 
 288 // Begins stack walking.
 289 //
 290 // Parameters:
 291 //   stackStream    StackStream object
 292 //   mode           Stack walking mode.
 293 //   skip_frames    Number of frames to be skipped.
 294 //   frame_count    Number of frames to be traversed.
 295 //   start_index    Start index to the user-supplied buffers.
 296 //   frames_array   Buffer to store StackFrame in, starting at start_index.
 297 //                  frames array is a Class<?>[] array when only getting caller
 298 //                  reference, and a StackFrameInfo[] array (or derivative)
 299 //                  otherwise. It should never be null.
 300 //
 301 // Returns Object returned from AbstractStackWalker::doStackWalk call.
 302 //
 303 oop StackWalk::walk(Handle stackStream, jlong mode,
 304                     int skip_frames, int frame_count, int start_index,
 305                     objArrayHandle frames_array,
 306                     TRAPS) {
 307   ResourceMark rm(THREAD);
 308   JavaThread* jt = (JavaThread*)THREAD;
 309   if (TraceStackWalk) {
 310     tty->print_cr("Start walking: mode " JLONG_FORMAT " skip %d frames batch size %d",
 311                   mode, skip_frames, frame_count);
 312   }
 313 
 314   if (frames_array.is_null()) {
 315     THROW_MSG_(vmSymbols::java_lang_NullPointerException(), "frames_array is NULL", NULL);
 316   }
 317 
 318   Klass* stackWalker_klass = SystemDictionary::StackWalker_klass();
 319   Klass* abstractStackWalker_klass = SystemDictionary::AbstractStackWalker_klass();
 320 
 321   methodHandle m_doStackWalk(THREAD, Universe::do_stack_walk_method());
 322 
 323   // Setup traversal onto my stack.
 324   RegisterMap regMap(jt, true);
 325   JavaFrameStream stream(jt, &regMap);
 326   {
 327     while (!stream.at_end()) {
 328       InstanceKlass* ik = stream.method()->method_holder();
 329       if (ik != stackWalker_klass &&
 330             ik != abstractStackWalker_klass && ik->super() != abstractStackWalker_klass)  {
 331         break;
 332       }
 333 
 334       if (TraceStackWalk) {
 335         tty->print("  skip "); stream.method()->print_short_name(); tty->print("\n");
 336       }
 337       stream.next();
 338     }
 339 
 340     // stack frame has been traversed individually and resume stack walk
 341     // from the stack frame at depth == skip_frames.
 342     for (int n=0; n < skip_frames && !stream.at_end(); stream.next(), n++) {
 343       if (TraceStackWalk) {
 344         tty->print("  skip "); stream.method()->print_short_name();
 345         tty->print_cr(" frame id: " PTR_FORMAT " pc: " PTR_FORMAT,
 346                       p2i(stream.java_frame()->fr().id()),
 347                       p2i(stream.java_frame()->fr().pc()));
 348       }
 349     }
 350   }
 351 
 352   int end_index = start_index;
 353   int numFrames = 0;
 354   if (!stream.at_end()) {
 355     numFrames = fill_in_frames(mode, stream, frame_count, start_index,
 356                                frames_array, end_index, CHECK_NULL);
 357     if (numFrames < 1) {
 358       THROW_MSG_(vmSymbols::java_lang_InternalError(), "stack walk: decode failed", NULL);
 359     }
 360   }
 361 
 362   // JVM_CallStackWalk walks the stack and fills in stack frames, then calls to
 363   // Java method java.lang.StackStreamFactory.AbstractStackWalker::doStackWalk
 364   // which calls the implementation to consume the stack frames.
 365   // When JVM_CallStackWalk returns, it invalidates the stack stream.
 366   JavaValue result(T_OBJECT);
 367   JavaCallArguments args(stackStream);
 368   args.push_long(stream.address_value());
 369   args.push_int(skip_frames);
 370   args.push_int(frame_count);
 371   args.push_int(start_index);
 372   args.push_int(end_index);
 373 
 374   // Link the thread and vframe stream into the callee-visible object
 375   stream.setup_magic_on_entry(frames_array);
 376 
 377   JavaCalls::call(&result, m_doStackWalk, &args, THREAD);
 378 
 379   // Do this before anything else happens, to disable any lingering stream objects
 380   bool ok = stream.cleanup_magic_on_exit(frames_array);
 381 
 382   // Throw pending exception if we must
 383   (void) (CHECK_NULL);
 384 
 385   if (!ok) {
 386     THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: corrupted buffers on exit", NULL);
 387   }
 388 
 389   // Return normally
 390   return (oop)result.get_jobject();
 391 }
 392 
 393 // Walk the next batch of stack frames
 394 //
 395 // Parameters:
 396 //   stackStream    StackStream object
 397 //   mode           Stack walking mode.
 398 //   magic          Must be valid value to continue the stack walk
 399 //   frame_count    Number of frames to be decoded.
 400 //   start_index    Start index to the user-supplied buffers.
 401 //   frames_array   Buffer to store StackFrame in, starting at start_index.
 402 //
 403 // Returns the end index of frame filled in the buffer.
 404 //
 405 jint StackWalk::moreFrames(Handle stackStream, jlong mode, jlong magic,
 406                            int frame_count, int start_index,
 407                            objArrayHandle frames_array,
 408                            TRAPS)
 409 {
 410   JavaThread* jt = (JavaThread*)THREAD;
 411   JavaFrameStream* existing_stream = JavaFrameStream::from_current(jt, magic, frames_array);
 412   if (existing_stream == NULL) {
 413     THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: corrupted buffers", 0L);
 414   }
 415 
 416   if (frames_array.is_null()) {
 417     THROW_MSG_(vmSymbols::java_lang_NullPointerException(), "frames_array is NULL", 0L);
 418   }
 419 
 420   if (TraceStackWalk) {
 421     tty->print_cr("StackWalk::moreFrames frame_count %d existing_stream " PTR_FORMAT " start %d frames %d",
 422                   frame_count, p2i(existing_stream), start_index, frames_array->length());
 423   }
 424   int end_index = start_index;
 425   if (frame_count <= 0) {
 426     return end_index;        // No operation.
 427   }
 428 
 429   int count = frame_count + start_index;
 430   assert (frames_array->length() >= count, "not enough space in buffers");
 431 
 432   JavaFrameStream& stream = (*existing_stream);
 433   if (!stream.at_end()) {
 434     stream.next(); // advance past the last frame decoded in previous batch
 435     if (!stream.at_end()) {
 436       int n = fill_in_frames(mode, stream, frame_count, start_index,
 437                              frames_array, end_index, CHECK_0);
 438       if (n < 1) {
 439         THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: later decode failed", 0L);
 440       }
 441       return end_index;
 442     }
 443   }
 444   return end_index;
 445 }