149 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			149 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			C++
		
	
	
	
/*
 | 
						|
 * Copyright (C) 2014 The Android Open Source Project
 | 
						|
 *
 | 
						|
 * Licensed under the Apache License, Version 2.0 (the "License");
 | 
						|
 * you may not use this file except in compliance with the License.
 | 
						|
 * You may obtain a copy of the License at
 | 
						|
 *
 | 
						|
 *      http://www.apache.org/licenses/LICENSE-2.0
 | 
						|
 *
 | 
						|
 * Unless required by applicable law or agreed to in writing, software
 | 
						|
 * distributed under the License is distributed on an "AS IS" BASIS,
 | 
						|
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 | 
						|
 * See the License for the specific language governing permissions and
 | 
						|
 * limitations under the License.
 | 
						|
 */
 | 
						|
 | 
						|
#include <pthread.h>
 | 
						|
#include <stdint.h>
 | 
						|
#include <stdlib.h>
 | 
						|
#include <sys/types.h>
 | 
						|
#include <unistd.h>
 | 
						|
 | 
						|
#include <backtrace/BacktraceMap.h>
 | 
						|
 | 
						|
#include <libunwind.h>
 | 
						|
 | 
						|
#include "BacktraceLog.h"
 | 
						|
#include "UnwindMap.h"
 | 
						|
 | 
						|
//-------------------------------------------------------------------------
 | 
						|
// libunwind has a single shared address space for the current process
 | 
						|
// aka local. If multiple maps are created for the current pid, then
 | 
						|
// only update the local address space once, and keep a reference count
 | 
						|
// of maps using the same map cursor.
 | 
						|
//-------------------------------------------------------------------------
 | 
						|
UnwindMap::UnwindMap(pid_t pid) : BacktraceMap(pid) {
 | 
						|
  unw_map_cursor_clear(&map_cursor_);
 | 
						|
}
 | 
						|
 | 
						|
UnwindMapRemote::UnwindMapRemote(pid_t pid) : UnwindMap(pid) {
 | 
						|
}
 | 
						|
 | 
						|
UnwindMapRemote::~UnwindMapRemote() {
 | 
						|
  unw_map_cursor_destroy(&map_cursor_);
 | 
						|
  unw_map_cursor_clear(&map_cursor_);
 | 
						|
}
 | 
						|
 | 
						|
bool UnwindMapRemote::GenerateMap() {
 | 
						|
  // Use the map_cursor information to construct the BacktraceMap data
 | 
						|
  // rather than reparsing /proc/self/maps.
 | 
						|
  unw_map_cursor_reset(&map_cursor_);
 | 
						|
 | 
						|
  unw_map_t unw_map;
 | 
						|
  while (unw_map_cursor_get_next(&map_cursor_, &unw_map)) {
 | 
						|
    backtrace_map_t map;
 | 
						|
 | 
						|
    map.start = unw_map.start;
 | 
						|
    map.end = unw_map.end;
 | 
						|
    map.offset = unw_map.offset;
 | 
						|
    map.load_bias = unw_map.load_base;
 | 
						|
    map.flags = unw_map.flags;
 | 
						|
    map.name = unw_map.path;
 | 
						|
 | 
						|
    // The maps are in descending order, but we want them in ascending order.
 | 
						|
    maps_.push_front(map);
 | 
						|
  }
 | 
						|
 | 
						|
  return true;
 | 
						|
}
 | 
						|
 | 
						|
bool UnwindMapRemote::Build() {
 | 
						|
  return (unw_map_cursor_create(&map_cursor_, pid_) == 0) && GenerateMap();
 | 
						|
}
 | 
						|
 | 
						|
UnwindMapLocal::UnwindMapLocal() : UnwindMap(getpid()), map_created_(false) {
 | 
						|
  pthread_rwlock_init(&map_lock_, nullptr);
 | 
						|
}
 | 
						|
 | 
						|
UnwindMapLocal::~UnwindMapLocal() {
 | 
						|
  if (map_created_) {
 | 
						|
    unw_map_local_destroy();
 | 
						|
    unw_map_cursor_clear(&map_cursor_);
 | 
						|
  }
 | 
						|
}
 | 
						|
 | 
						|
bool UnwindMapLocal::GenerateMap() {
 | 
						|
  // Lock so that multiple threads cannot modify the maps data at the
 | 
						|
  // same time.
 | 
						|
  pthread_rwlock_wrlock(&map_lock_);
 | 
						|
 | 
						|
  // It's possible for the map to be regenerated while this loop is occurring.
 | 
						|
  // If that happens, get the map again, but only try at most three times
 | 
						|
  // before giving up.
 | 
						|
  bool generated = false;
 | 
						|
  for (int i = 0; i < 3; i++) {
 | 
						|
    maps_.clear();
 | 
						|
 | 
						|
    // Save the map data retrieved so we can tell if it changes.
 | 
						|
    unw_map_local_cursor_get(&map_cursor_);
 | 
						|
 | 
						|
    unw_map_t unw_map;
 | 
						|
    int ret;
 | 
						|
    while ((ret = unw_map_local_cursor_get_next(&map_cursor_, &unw_map)) > 0) {
 | 
						|
      backtrace_map_t map;
 | 
						|
 | 
						|
      map.start = unw_map.start;
 | 
						|
      map.end = unw_map.end;
 | 
						|
      map.offset = unw_map.offset;
 | 
						|
      map.load_bias = unw_map.load_base;
 | 
						|
      map.flags = unw_map.flags;
 | 
						|
      map.name = unw_map.path;
 | 
						|
 | 
						|
      free(unw_map.path);
 | 
						|
 | 
						|
      // The maps are in descending order, but we want them in ascending order.
 | 
						|
      maps_.push_front(map);
 | 
						|
    }
 | 
						|
    // Check to see if the map changed while getting the data.
 | 
						|
    if (ret != -UNW_EINVAL) {
 | 
						|
      generated = true;
 | 
						|
      break;
 | 
						|
    }
 | 
						|
  }
 | 
						|
 | 
						|
  pthread_rwlock_unlock(&map_lock_);
 | 
						|
 | 
						|
  if (!generated) {
 | 
						|
    BACK_LOGW("Unable to generate the map.");
 | 
						|
  }
 | 
						|
  return generated;
 | 
						|
}
 | 
						|
 | 
						|
bool UnwindMapLocal::Build() {
 | 
						|
  return (map_created_ = (unw_map_local_create() == 0)) && GenerateMap();;
 | 
						|
}
 | 
						|
 | 
						|
void UnwindMapLocal::FillIn(uint64_t addr, backtrace_map_t* map) {
 | 
						|
  BacktraceMap::FillIn(addr, map);
 | 
						|
  if (!IsValid(*map)) {
 | 
						|
    // Check to see if the underlying map changed and regenerate the map
 | 
						|
    // if it did.
 | 
						|
    if (unw_map_local_cursor_valid(&map_cursor_) < 0) {
 | 
						|
      if (GenerateMap()) {
 | 
						|
        BacktraceMap::FillIn(addr, map);
 | 
						|
      }
 | 
						|
    }
 | 
						|
  }
 | 
						|
}
 |