1 /*
   2  * Copyright (c) 2015, 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 StackWalkAnchor::setup_magic_on_entry() {
  41   _frames->obj_at_put(StackWalk::magic_pos, _thread->threadObj());
  42   _anchor = address_value();
  43   assert(check_magic(), "invalid magic");
  44 }
  45 
  46 bool StackWalkAnchor::check_magic() {
  47   oop   m1 = _frames->obj_at(StackWalk::magic_pos);
  48   jlong m2 = _anchor;
  49   if (m1 == _thread->threadObj() && m2 == address_value())  return true;
  50   return false;
  51 }
  52 
  53 bool StackWalkAnchor::cleanup_magic_on_exit() {
  54   bool ok = check_magic();
  55   _frames->obj_at_put(StackWalk::magic_pos, NULL);
  56   _anchor = 0L;
  57   return ok;
  58 }
  59 
  60 /**
  61  * Returns StackWalkAnchor for the current stack being traversed.
  62  *
  63  * @argument thread.       Current Java thread.
  64  * @argument magic.        Magic value used for each stack walking
  65  * @argument classes_array User-supplied buffers.  The 0th element is reserved
  66  *                         to this StackWalkAnchor to use
  67  */
  68 StackWalkAnchor* StackWalkAnchor::from_current(JavaThread* thread, jlong magic,
  69                                                objArrayHandle classes_array)
  70 {
  71   assert(thread != NULL && thread->is_Java_thread(), "");
  72   oop m1 = classes_array->obj_at(StackWalk::magic_pos);
  73   if (m1 != thread->threadObj())      return NULL;
  74   if (magic == 0L)                    return NULL;
  75   StackWalkAnchor* anchor = (StackWalkAnchor*) (intptr_t) magic;
  76   if (!anchor->is_valid_in(thread))   return NULL;
  77   return anchor;
  78 }
  79 
  80 /*
  81  * Unpacks one or more frames into user-supplied buffers.
  82  * Updates the end index, and returns the number of unpacked frames.
  83  * Always start with the existing vfst.method and bci.
  84  * Do not call vfst.next to advance over the last returned value.
  85  * In other words, do not leave any stale data in the vfst.
  86  *
  87  * @argument mode.          Restrict which frames to be decoded.
  88  * @argument decode_limit.  Maximum of frames to be decoded.
  89  * @argument start_index.   Start index to the user-supplied buffers.
  90  * @argument classes_array. Buffer to store classes in, starting at start_index.
  91  * @argument frames_array.  Buffer to store StackFrame in, starting at start_index.
  92  *                          NULL if not used.
  93  * @argument end_index.     End index to the user-supplied buffers
  94  *                          with unpacked frames.
  95  *
  96  * @return Number of frames whose information was transferred into the buffers.
  97  */
  98 int StackWalkAnchor::decode_frames(jlong mode, int decode_limit, int start_index,
  99                                    objArrayHandle  classes_array,
 100                                    objArrayHandle  frames_array,
 101                                    int& end_index, TRAPS) {
 102   if (TraceStackWalk) {
 103     tty->print_cr("decode_frames limit=%d start=%d frames length=%d",
 104                   decode_limit, start_index, classes_array->length());
 105   }
 106   assert(decode_limit > 0, "invalid decode_limit");
 107   assert(start_index + decode_limit <= classes_array->length(), "oob");
 108 
 109   int frames_decoded = 0;
 110   for (; !_vfst.at_end(); _vfst.next()) {
 111     Method* method = _vfst.method();
 112     int bci = _vfst.bci();
 113 
 114     if (method == NULL) continue;
 115     if (!ShowHiddenFrames && StackWalk::skip_hidden_frames(mode)) {
 116         if (method->is_hidden()) {
 117           if (TraceStackWalk) {
 118             tty->print("  hidden method: "); method->print_short_name();
 119             tty->print("\n");
 120           }
 121           continue;
 122         }
 123     }
 124 
 125     int index = end_index++;
 126     if (TraceStackWalk) {
 127       tty->print("  %d: frame method: ", index); method->print_short_name();
 128       tty->print_cr(" bci=%d", bci);
 129     }
 130 
 131     classes_array->obj_at_put(index, method->method_holder()->java_mirror());
 132     // fill in StackFrameInfo and initialize MemberName
 133     if (StackWalk::live_frame_info(mode)) {
 134       Handle stackFrame(frames_array->obj_at(index));
 135       StackWalk::fill_live_stackframe(stackFrame, method, bci, _vfst.java_frame(), CHECK_0);
 136     } else if (StackWalk::need_method_info(mode)) {
 137       Handle stackFrame(frames_array->obj_at(index));
 138       StackWalk::fill_stackframe(stackFrame, method, bci);
 139     }
 140     if (++frames_decoded >= decode_limit)  break;
 141   }
 142   return frames_decoded;
 143 }
 144 
 145 static oop create_primitive_value_instance(StackValueCollection* values, int i, TRAPS) {
 146     Klass* k = SystemDictionary::resolve_or_null(vmSymbols::java_lang_LiveStackFrameInfo(), CHECK_NULL);
 147     instanceKlassHandle ik (THREAD, k);
 148 
 149     JavaValue result(T_OBJECT);
 150     JavaCallArguments args;
 151     Symbol* signature = NULL;
 152 
 153     // ## TODO: type is only available in LocalVariable table, if present.
 154     // ## StackValue type is T_INT or T_OBJECT.
 155     switch (values->at(i)->type()) {
 156         case T_INT:
 157             args.push_int(values->int_at(i));
 158             signature = vmSymbols::asPrimitive_int_signature();
 159             break;
 160 
 161         case T_LONG:
 162             args.push_long(values->long_at(i));
 163             signature = vmSymbols::asPrimitive_long_signature();
 164             break;
 165 
 166         case T_FLOAT:
 167             args.push_float(values->float_at(i));
 168             signature = vmSymbols::asPrimitive_float_signature();
 169             break;
 170 
 171         case T_DOUBLE:
 172             args.push_double(values->double_at(i));
 173             signature = vmSymbols::asPrimitive_double_signature();
 174             break;
 175 
 176         case T_BYTE:
 177             args.push_int(values->int_at(i));
 178             signature = vmSymbols::asPrimitive_byte_signature();
 179             break;
 180 
 181         case T_SHORT:
 182             args.push_int(values->int_at(i));
 183             signature = vmSymbols::asPrimitive_short_signature();
 184             break;
 185 
 186         case T_CHAR:
 187             args.push_int(values->int_at(i));
 188             signature = vmSymbols::asPrimitive_char_signature();
 189             break;
 190 
 191         case T_BOOLEAN:
 192             args.push_int(values->int_at(i));
 193             signature = vmSymbols::asPrimitive_boolean_signature();
 194             break;
 195 
 196         case T_OBJECT:
 197             return values->obj_at(i)();
 198 
 199         case T_CONFLICT:
 200             // put a non-null slot
 201             args.push_int(0);
 202             signature = vmSymbols::asPrimitive_int_signature();
 203             break;
 204             
 205         default: ShouldNotReachHere();
 206     }
 207     JavaCalls::call_static(&result,
 208                            ik,
 209                            vmSymbols::asPrimitive_name(),
 210                            signature,
 211                            &args,
 212                            CHECK_NULL);
 213     return (instanceOop) result.get_jobject();
 214 }
 215 
 216 static objArrayHandle values_to_object_array(StackValueCollection* values, TRAPS) {
 217   objArrayHandle empty;
 218   int length = values->size();
 219   objArrayOop array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(),
 220                                                    length, CHECK_(empty));
 221   objArrayHandle array_h(THREAD, array_oop);
 222   for (int i = 0; i < values->size(); i++) {
 223     StackValue* st = values->at(i);
 224     oop obj = create_primitive_value_instance(values, i, CHECK_(empty));
 225     if (obj != NULL)
 226       array_h->obj_at_put(i, obj);
 227   }
 228   return array_h;
 229 }
 230 
 231 static objArrayHandle monitors_to_object_array(GrowableArray<MonitorInfo*>* monitors, TRAPS) {
 232   int length = monitors->length();
 233   objArrayOop array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(),
 234                                                    length, CHECK_(objArrayHandle()));
 235   objArrayHandle array_h(THREAD, array_oop);
 236   for (int i = 0; i < length; i++) {
 237     MonitorInfo* monitor = monitors->at(i);
 238     array_h->obj_at_put(i, monitor->owner());
 239   }
 240   return array_h;
 241 }
 242 
 243 /*
 244  * Fill StackFrameInfo with declaringClass and bci and initialize memberName
 245  */
 246 void StackWalk::fill_stackframe(Handle stackFrame, const methodHandle& method, int bci) {
 247   if (TraceStackWalk) {
 248     tty->print("     member name: "); method->print_short_name();
 249     tty->print_cr(" bci=%d", bci);
 250   }
 251 
 252   java_lang_StackFrameInfo::set_declaringClass(stackFrame(), method->method_holder()->java_mirror());
 253   java_lang_StackFrameInfo::set_method_and_bci(stackFrame(), method, bci);
 254 }
 255 
 256 /*
 257  * Fill LiveStackFrameInfo with locals, monitors, and expressions
 258  */
 259 
 260 void StackWalk::fill_live_stackframe(Handle stackFrame, const methodHandle& method, int bci, javaVFrame* jvf, TRAPS) {
 261   fill_stackframe(stackFrame, method, bci);
 262  
 263   if (jvf != NULL) {
 264     StackValueCollection* locals = jvf->locals();
 265     StackValueCollection* expressions = jvf->expressions();
 266     GrowableArray<MonitorInfo*>* monitors = jvf->monitors();
 267 
 268     if (!locals->is_empty()) {
 269       objArrayHandle locals_h = values_to_object_array(locals, CHECK);
 270       java_lang_LiveStackFrameInfo::set_locals(stackFrame(), locals_h());
 271     }
 272     if (!expressions->is_empty()) {
 273       objArrayHandle expressions_h = values_to_object_array(expressions, CHECK);
 274       java_lang_LiveStackFrameInfo::set_operands(stackFrame(), expressions_h());
 275     }
 276     if (monitors->length() > 0) {
 277       objArrayHandle monitors_h = monitors_to_object_array(monitors, CHECK);
 278       java_lang_LiveStackFrameInfo::set_monitors(stackFrame(), monitors_h());
 279     }
 280   }
 281 }
 282 
 283 /*
 284  * Begins stack walking.
 285  *
 286  * @argument stackStream.   StackStream object
 287  * @argument mode.          Stack walking mode.
 288  * @argument skip_frames.   Number of frames to be skipped.
 289  * @argument frame_count.   Number of frames to be traversed.
 290  * @argument start_index.   Start index to the user-supplied buffers.
 291  * @argument classes_array. Buffer to store classes in, starting at start_index.
 292  * @argument frames_array.  Buffer to store StackFrame in, starting at start_index.
 293  *                          NULL if not used.
 294  * @return   Object returned from AbstractStackWalker::doStackWalk call.
 295  */
 296 Handle StackWalk::walk(Handle stackStream, jlong mode,
 297                        int skip_frames, int frame_count, int start_index,
 298                        objArrayHandle  classes_array,
 299                        objArrayHandle  frames_array,
 300                        TRAPS)
 301 {
 302   Handle empty;
 303 
 304   JavaThread* jt = (JavaThread*)THREAD;
 305   if (TraceStackWalk) {
 306     tty->print_cr("Start walking: mode " JLONG_FORMAT " skip %d frames batch size %d", mode, skip_frames, frame_count);
 307   }
 308 
 309   if (need_method_info(mode)) {
 310     if (frames_array.is_null()) {
 311       THROW_MSG_(vmSymbols::java_lang_NullPointerException(), "frames_array is NULL", empty);
 312     }
 313   }
 314 
 315   Klass* stackWalker_klass = SystemDictionary::StackWalker_klass();
 316   Klass* abstractStackWalker_klass = SystemDictionary::AbstractStackWalker_klass();
 317 
 318   methodHandle m_doStackWalk(THREAD, Universe::stack_walker_callback_method());
 319 
 320   // Open up a traversable stream onto my stack.
 321   // This stream will be made available by *reference* to the inner Java call.
 322   StackWalkAnchor anchor(jt, classes_array);
 323   vframeStream& vfst = anchor.vframe_stream();
 324 
 325   {
 326     // Skip all methods from AbstractStackWalker and StackWalk (enclosing method)
 327     if (!fill_in_stacktrace(mode)) {
 328       while (!vfst.at_end()) {
 329         InstanceKlass* ik = vfst.method()->method_holder();
 330         if (ik != stackWalker_klass && ik != abstractStackWalker_klass && ik->super() != abstractStackWalker_klass)  {
 331           break;
 332         }
 333 
 334         if (TraceStackWalk) {
 335           tty->print("  skip "); vfst.method()->print_short_name(); tty->print("\n");
 336         }
 337         vfst.next();
 338       }
 339     }
 340 
 341     // For exceptions, skip Throwable::fillInStackTrace and <init> methods
 342     // of the exception class and superclasses
 343     if (fill_in_stacktrace(mode)) {
 344       bool skip_to_fillInStackTrace = false;
 345       bool skip_throwableInit_check = false;
 346       while (!vfst.at_end() && !skip_throwableInit_check) {
 347         InstanceKlass* ik = vfst.method()->method_holder();
 348         Method* method = vfst.method();
 349         if (!skip_to_fillInStackTrace) {
 350           if (ik == SystemDictionary::Throwable_klass() &&
 351               method->name() == vmSymbols::fillInStackTrace_name()) {
 352               // this frame will be skipped
 353               skip_to_fillInStackTrace = true;
 354           }
 355         } else if (!(ik->is_subclass_of(SystemDictionary::Throwable_klass()) &&
 356                      method->name() == vmSymbols::object_initializer_name())) {
 357             // there are none or we've seen them all - either way stop checking
 358             skip_throwableInit_check = true;
 359             break;
 360         }
 361 
 362         if (TraceStackWalk) {
 363           tty->print("stack walk: skip "); vfst.method()->print_short_name(); tty->print("\n");
 364         }
 365         vfst.next();
 366       }
 367     }
 368 
 369     // stack frame has been traversed individually and resume stack walk
 370     // from the stack frame at depth == skip_frames.
 371     for (int n=0; n < skip_frames && !vfst.at_end(); vfst.next(), n++) {
 372       if (TraceStackWalk) {
 373         tty->print("  skip "); vfst.method()->print_short_name();
 374         tty->print_cr(" frame id: " PTR_FORMAT " pc: " PTR_FORMAT,
 375                       p2i(vfst.frame_id()), p2i(vfst.frame_pc()));
 376       }
 377     }
 378   }
 379 
 380   // The Method* pointer in the vfst has a very short shelf life.  Grab it now.
 381   int end_index = start_index;
 382   int numFrames = 0;
 383   if (!vfst.at_end()) {
 384     numFrames = anchor.decode_frames(mode, frame_count, start_index, classes_array,
 385                                      frames_array, end_index, CHECK_(empty));
 386     if (numFrames < 1) {
 387       THROW_MSG_(vmSymbols::java_lang_InternalError(), "stack walk: decode failed", empty);
 388     }
 389   }
 390 
 391   // call StackStream::doStackWalk to do bulk traversal on the entire stack
 392   JavaValue result(T_OBJECT);
 393   JavaCallArguments args(stackStream);
 394   args.push_long(anchor.address_value());
 395   args.push_int(skip_frames);
 396   args.push_int(frame_count);
 397   args.push_int(start_index);
 398   args.push_int(end_index);
 399 
 400   // Link the thread and vframe stream into the callee-visible object:
 401   anchor.setup_magic_on_entry();
 402 
 403   JavaCalls::call(&result, m_doStackWalk, &args, THREAD);
 404 
 405   // Do this before anything else happens, to disable any lingering stream objects:
 406   bool ok = anchor.cleanup_magic_on_exit();
 407 
 408   // Throw pending exception if we must:
 409   (void) (CHECK_(empty));
 410 
 411   if (!ok) {
 412     THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: corrupted buffers on exit", empty);
 413   }
 414 
 415   Handle obj(THREAD, (oop) result.get_jobject());
 416   // Return normally:
 417   return obj;
 418 
 419 }
 420 
 421 /*
 422  * Walk the next batch of stack frames
 423  *
 424  * @argument stackStream.   StackStream object
 425  * @argument mode.          Stack walking mode.
 426  * @argument magic.         Must be valid value to continue the stack walk
 427  * @argument frame_count.   Number of frames to be decoded.
 428  * @argument start_index.   Start index to the user-supplied buffers.
 429  * @argument classes_array. Buffer to store classes in, starting at start_index.
 430  * @argument frames_array.  Buffer to store StackFrame in, starting at start_index.
 431  *                          NULL if not used.
 432  * @return   End index
 433  */
 434 jint StackWalk::moreFrames(Handle stackStream, jlong mode, jlong magic,
 435                            int frame_count, int start_index,
 436                            objArrayHandle classes_array,
 437                            objArrayHandle frames_array,
 438                            TRAPS)
 439 {
 440   JavaThread* jt = (JavaThread*)THREAD;
 441   StackWalkAnchor* existing_anchor = StackWalkAnchor::from_current(jt, magic, classes_array);
 442   if (existing_anchor == NULL) {
 443     THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: corrupted buffers", 0L);
 444   }
 445 
 446   if ((need_method_info(mode) || live_frame_info(mode)) && frames_array.is_null()) {
 447     THROW_MSG_(vmSymbols::java_lang_NullPointerException(), "frames_array is NULL", 0L);
 448   }
 449 
 450   if (TraceStackWalk) {
 451     tty->print_cr("StackWalk::moreFrames frame_count %d existing_anchor " PTR_FORMAT " start %d frames %d",
 452                   frame_count, p2i(existing_anchor), start_index, classes_array->length());
 453   }
 454   int end_index = start_index;
 455   if (frame_count <= 0) {
 456     return end_index;        // No operation.
 457   }
 458 
 459   int count = frame_count+start_index;
 460   assert (classes_array->length() >= count, "not enough space in buffers");
 461 
 462   StackWalkAnchor& anchor = (*existing_anchor);
 463   vframeStream& vfst = anchor.vframe_stream();
 464   if (!vfst.at_end()) {
 465     vfst.next();  // skip java.lang.StackStream::moreStackWalk
 466     if (!vfst.at_end()) {
 467       int n = anchor.decode_frames(mode, frame_count, start_index, classes_array,
 468                                    frames_array, end_index, CHECK_0);
 469       if (n < 1) {
 470         THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: later decode failed", 0L);
 471       }
 472       return end_index;
 473     }
 474   }
 475   return end_index;
 476 }