File: BacktraceMap.cpp

package info (click to toggle)
android-platform-system-core 1%3A7.0.0%2Br33-1
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 10,464 kB
  • sloc: cpp: 96,742; ansic: 39,563; asm: 3,482; python: 1,571; sh: 666; lex: 311; java: 169; makefile: 65; xml: 19
file content (154 lines) | stat: -rw-r--r-- 4,502 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
/*
 * 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 <algorithm>
#include <ctype.h>
#include <stdint.h>
#include <sys/types.h>
#include <unistd.h>

#include <backtrace/backtrace_constants.h>
#include <backtrace/BacktraceMap.h>
#include <log/log.h>

#include "thread_utils.h"

BacktraceMap::BacktraceMap(pid_t pid) : pid_(pid) {
  if (pid_ < 0) {
    pid_ = getpid();
  }
}

BacktraceMap::~BacktraceMap() {
}

void BacktraceMap::FillIn(uintptr_t addr, backtrace_map_t* map) {
  for (BacktraceMap::const_iterator it = begin();
       it != end(); ++it) {
    if (addr >= it->start && addr < it->end) {
      *map = *it;
      return;
    }
  }
  *map = {};
}

bool BacktraceMap::ParseLine(const char* line, backtrace_map_t* map) {
  unsigned long int start;
  unsigned long int end;
  char permissions[5];
  int name_pos;

#if defined(__APPLE__)
// Mac OS vmmap(1) output:
// __TEXT                 0009f000-000a1000 [    8K     8K] r-x/rwx SM=COW  /Volumes/android/dalvik-dev/out/host/darwin-x86/bin/libcorkscrew_test\n
// 012345678901234567890123456789012345678901234567890123456789
// 0         1         2         3         4         5
  if (sscanf(line, "%*21c %lx-%lx [%*13c] %3c/%*3c SM=%*3c  %n",
             &start, &end, permissions, &name_pos) != 3) {
#else
// Linux /proc/<pid>/maps lines:
// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419   /system/lib/libcomposer.so\n
// 012345678901234567890123456789012345678901234567890123456789
// 0         1         2         3         4         5
  if (sscanf(line, "%lx-%lx %4s %*x %*x:%*x %*d %n",
             &start, &end, permissions, &name_pos) != 3) {
#endif
    return false;
  }

  map->start = start;
  map->end = end;
  map->flags = PROT_NONE;
  if (permissions[0] == 'r') {
    map->flags |= PROT_READ;
  }
  if (permissions[1] == 'w') {
    map->flags |= PROT_WRITE;
  }
  if (permissions[2] == 'x') {
    map->flags |= PROT_EXEC;
  }

  map->name = line+name_pos;
  if (!map->name.empty() && map->name[map->name.length()-1] == '\n') {
    map->name.erase(map->name.length()-1);
  }

  ALOGV("Parsed map: start=%p, end=%p, flags=%x, name=%s",
        reinterpret_cast<void*>(map->start), reinterpret_cast<void*>(map->end),
        map->flags, map->name.c_str());
  return true;
}

bool BacktraceMap::Build() {
#if defined(__APPLE__)
  char cmd[sizeof(pid_t)*3 + sizeof("vmmap -w -resident -submap -allSplitLibs -interleaved ") + 1];
#else
  char path[sizeof(pid_t)*3 + sizeof("/proc//maps") + 1];
#endif
  char line[1024];

#if defined(__APPLE__)
  // cmd is guaranteed to always be big enough to hold this string.
  snprintf(cmd, sizeof(cmd), "vmmap -w -resident -submap -allSplitLibs -interleaved %d", pid_);
  FILE* fp = popen(cmd, "r");
#else
  // path is guaranteed to always be big enough to hold this string.
  snprintf(path, sizeof(path), "/proc/%d/maps", pid_);
  FILE* fp = fopen(path, "r");
#endif
  if (fp == nullptr) {
    return false;
  }

  while(fgets(line, sizeof(line), fp)) {
    backtrace_map_t map;
    if (ParseLine(line, &map)) {
      maps_.push_back(map);
    }
  }
#if defined(__APPLE__)
  pclose(fp);
#else
  fclose(fp);
#endif

  return true;
}

#if defined(__APPLE__)
// Corkscrew and libunwind don't compile on the mac, so create a generic
// map object.
BacktraceMap* BacktraceMap::Create(pid_t pid, bool /*uncached*/) {
  BacktraceMap* map = new BacktraceMap(pid);
  if (!map->Build()) {
    delete map;
    return nullptr;
  }
  return map;
}
#endif

BacktraceMap* BacktraceMap::Create(pid_t pid, const std::vector<backtrace_map_t>& maps) {
    BacktraceMap* backtrace_map = new BacktraceMap(pid);
    backtrace_map->maps_.insert(backtrace_map->maps_.begin(), maps.begin(), maps.end());
    std::sort(backtrace_map->maps_.begin(), backtrace_map->maps_.end(),
            [](const backtrace_map_t& map1, const backtrace_map_t& map2) {
              return map1.start < map2.start;
            });
    return backtrace_map;
}