1 /*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define LOG_TAG "backtrace-map"
18
19 #include <ctype.h>
20 #include <inttypes.h>
21 #include <stdint.h>
22 #include <sys/types.h>
23 #include <unistd.h>
24
25 #include <log/log.h>
26
27 #include <backtrace/backtrace_constants.h>
28 #include <backtrace/BacktraceMap.h>
29
30 #include "thread_utils.h"
31
BacktraceMap(pid_t pid)32 BacktraceMap::BacktraceMap(pid_t pid) : pid_(pid) {
33 if (pid_ < 0) {
34 pid_ = getpid();
35 }
36 }
37
~BacktraceMap()38 BacktraceMap::~BacktraceMap() {
39 }
40
FillIn(uintptr_t addr,backtrace_map_t * map)41 void BacktraceMap::FillIn(uintptr_t addr, backtrace_map_t* map) {
42 ScopedBacktraceMapIteratorLock lock(this);
43 for (BacktraceMap::const_iterator it = begin(); it != end(); ++it) {
44 if (addr >= it->start && addr < it->end) {
45 *map = *it;
46 return;
47 }
48 }
49 *map = {};
50 }
51
ParseLine(const char * line,backtrace_map_t * map)52 bool BacktraceMap::ParseLine(const char* line, backtrace_map_t* map) {
53 uint64_t start;
54 uint64_t end;
55 char permissions[5];
56 int name_pos;
57
58 #if defined(__APPLE__)
59 // Mac OS vmmap(1) output:
60 // __TEXT 0009f000-000a1000 [ 8K 8K] r-x/rwx SM=COW /Volumes/android/dalvik-dev/out/host/darwin-x86/bin/libcorkscrew_test\n
61 // 012345678901234567890123456789012345678901234567890123456789
62 // 0 1 2 3 4 5
63 if (sscanf(line, "%*21c %" SCNx64 "-%" SCNx64 " [%*13c] %3c/%*3c SM=%*3c %n",
64 &start, &end, permissions, &name_pos) != 3) {
65 #else
66 // Linux /proc/<pid>/maps lines:
67 // 6f000000-6f01e000 rwxp 00000000 00:0c 16389419 /system/lib/libcomposer.so\n
68 // 012345678901234567890123456789012345678901234567890123456789
69 // 0 1 2 3 4 5
70 if (sscanf(line, "%" SCNx64 "-%" SCNx64 " %4s %*x %*x:%*x %*d %n",
71 &start, &end, permissions, &name_pos) != 3) {
72 #endif
73 return false;
74 }
75
76 map->start = start;
77 map->end = end;
78 map->flags = PROT_NONE;
79 if (permissions[0] == 'r') {
80 map->flags |= PROT_READ;
81 }
82 if (permissions[1] == 'w') {
83 map->flags |= PROT_WRITE;
84 }
85 if (permissions[2] == 'x') {
86 map->flags |= PROT_EXEC;
87 }
88
89 map->name = line+name_pos;
90 if (!map->name.empty() && map->name[map->name.length()-1] == '\n') {
91 map->name.erase(map->name.length()-1);
92 }
93
94 ALOGV("Parsed map: start=%p, end=%p, flags=%x, name=%s",
95 reinterpret_cast<void*>(map->start), reinterpret_cast<void*>(map->end),
96 map->flags, map->name.c_str());
97 return true;
98 }
99
100 bool BacktraceMap::Build() {
101 #if defined(__APPLE__)
102 char cmd[sizeof(pid_t)*3 + sizeof("vmmap -w -resident -submap -allSplitLibs -interleaved ") + 1];
103 #else
104 char path[sizeof(pid_t)*3 + sizeof("/proc//maps") + 1];
105 #endif
106 char line[1024];
107
108 #if defined(__APPLE__)
109 // cmd is guaranteed to always be big enough to hold this string.
110 snprintf(cmd, sizeof(cmd), "vmmap -w -resident -submap -allSplitLibs -interleaved %d", pid_);
111 FILE* fp = popen(cmd, "r");
112 #else
113 // path is guaranteed to always be big enough to hold this string.
114 snprintf(path, sizeof(path), "/proc/%d/maps", pid_);
115 FILE* fp = fopen(path, "r");
116 #endif
117 if (fp == nullptr) {
118 return false;
119 }
120
121 while(fgets(line, sizeof(line), fp)) {
122 backtrace_map_t map;
123 if (ParseLine(line, &map)) {
124 maps_.push_back(map);
125 }
126 }
127 #if defined(__APPLE__)
128 pclose(fp);
129 #else
130 fclose(fp);
131 #endif
132
133 return true;
134 }
135
136 #if defined(__APPLE__)
137 // Corkscrew and libunwind don't compile on the mac, so create a generic
138 // map object.
139 BacktraceMap* BacktraceMap::Create(pid_t pid, bool /*uncached*/) {
140 BacktraceMap* map = new BacktraceMap(pid);
141 if (!map->Build()) {
142 delete map;
143 return nullptr;
144 }
145 return map;
146 }
147 #endif
148
149 BacktraceMap* BacktraceMap::Create(pid_t pid, const std::vector<backtrace_map_t>& maps) {
150 BacktraceMap* backtrace_map = new BacktraceMap(pid);
151 backtrace_map->maps_.insert(backtrace_map->maps_.begin(), maps.begin(), maps.end());
152 std::sort(backtrace_map->maps_.begin(), backtrace_map->maps_.end(),
153 [](const backtrace_map_t& map1, const backtrace_map_t& map2) {
154 return map1.start < map2.start;
155 });
156 return backtrace_map;
157 }
158