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 #include <ctype.h>
18 #include <stdint.h>
19 #include <sys/types.h>
20 #include <unistd.h>
21
22 #include <backtrace/backtrace_constants.h>
23 #include <backtrace/BacktraceMap.h>
24 #include <log/log.h>
25
26 #include "thread_utils.h"
27
BacktraceMap(pid_t pid)28 BacktraceMap::BacktraceMap(pid_t pid) : pid_(pid) {
29 if (pid_ < 0) {
30 pid_ = getpid();
31 }
32 }
33
~BacktraceMap()34 BacktraceMap::~BacktraceMap() {
35 }
36
FillIn(uintptr_t addr,backtrace_map_t * map)37 void BacktraceMap::FillIn(uintptr_t addr, backtrace_map_t* map) {
38 for (BacktraceMap::const_iterator it = begin();
39 it != end(); ++it) {
40 if (addr >= it->start && addr < it->end) {
41 *map = *it;
42 return;
43 }
44 }
45 *map = {};
46 }
47
ParseLine(const char * line,backtrace_map_t * map)48 bool BacktraceMap::ParseLine(const char* line, backtrace_map_t* map) {
49 unsigned long int start;
50 unsigned long int end;
51 char permissions[5];
52 int name_pos;
53
54 #if defined(__APPLE__)
55 // Mac OS vmmap(1) output:
56 // __TEXT 0009f000-000a1000 [ 8K 8K] r-x/rwx SM=COW /Volumes/android/dalvik-dev/out/host/darwin-x86/bin/libcorkscrew_test\n
57 // 012345678901234567890123456789012345678901234567890123456789
58 // 0 1 2 3 4 5
59 if (sscanf(line, "%*21c %lx-%lx [%*13c] %3c/%*3c SM=%*3c %n",
60 &start, &end, permissions, &name_pos) != 3) {
61 #else
62 // Linux /proc/<pid>/maps lines:
63 // 6f000000-6f01e000 rwxp 00000000 00:0c 16389419 /system/lib/libcomposer.so\n
64 // 012345678901234567890123456789012345678901234567890123456789
65 // 0 1 2 3 4 5
66 if (sscanf(line, "%lx-%lx %4s %*x %*x:%*x %*d%n",
67 &start, &end, permissions, &name_pos) != 3) {
68 #endif
69 return false;
70 }
71
72 map->start = start;
73 map->end = end;
74 map->flags = PROT_NONE;
75 if (permissions[0] == 'r') {
76 map->flags |= PROT_READ;
77 }
78 if (permissions[1] == 'w') {
79 map->flags |= PROT_WRITE;
80 }
81 if (permissions[2] == 'x') {
82 map->flags |= PROT_EXEC;
83 }
84
85 while (isspace(line[name_pos])) {
86 name_pos += 1;
87 }
88 map->name = line+name_pos;
89 if (!map->name.empty() && map->name[map->name.length()-1] == '\n') {
90 map->name.erase(map->name.length()-1);
91 }
92
93 ALOGV("Parsed map: start=%p, end=%p, flags=%x, name=%s",
94 reinterpret_cast<void*>(map->start), reinterpret_cast<void*>(map->end),
95 map->flags, map->name.c_str());
96 return true;
97 }
98
99 bool BacktraceMap::Build() {
100 #if defined(__APPLE__)
101 char cmd[sizeof(pid_t)*3 + sizeof("vmmap -w -resident -submap -allSplitLibs -interleaved ") + 1];
102 #else
103 char path[sizeof(pid_t)*3 + sizeof("/proc//maps") + 1];
104 #endif
105 char line[1024];
106
107 #if defined(__APPLE__)
108 // cmd is guaranteed to always be big enough to hold this string.
109 snprintf(cmd, sizeof(cmd), "vmmap -w -resident -submap -allSplitLibs -interleaved %d", pid_);
110 FILE* fp = popen(cmd, "r");
111 #else
112 // path is guaranteed to always be big enough to hold this string.
113 snprintf(path, sizeof(path), "/proc/%d/maps", pid_);
114 FILE* fp = fopen(path, "r");
115 #endif
116 if (fp == nullptr) {
117 return false;
118 }
119
120 while(fgets(line, sizeof(line), fp)) {
121 backtrace_map_t map;
122 if (ParseLine(line, &map)) {
123 maps_.push_back(map);
124 }
125 }
126 #if defined(__APPLE__)
127 pclose(fp);
128 #else
129 fclose(fp);
130 #endif
131
132 return true;
133 }
134
135 #if defined(__APPLE__)
136 // Corkscrew and libunwind don't compile on the mac, so create a generic
137 // map object.
138 BacktraceMap* BacktraceMap::Create(pid_t pid, bool uncached) {
139 BacktraceMap* map = new BacktraceMap(pid);
140 if (!map->Build()) {
141 delete map;
142 return nullptr;
143 }
144 return map;
145 }
146 #endif
147