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 <android-base/stringprintf.h>
28 #include <backtrace/Backtrace.h>
29 #include <backtrace/BacktraceMap.h>
30 #include <backtrace/backtrace_constants.h>
31
32 #include "thread_utils.h"
33
34 using android::base::StringPrintf;
35
Name() const36 std::string backtrace_map_t::Name() const {
37 if (!name.empty()) return name;
38 if (start == 0 && end == 0) return "";
39 return StringPrintf("<anonymous:%" PRIPTR ">", start);
40 }
41
BacktraceMap(pid_t pid)42 BacktraceMap::BacktraceMap(pid_t pid) : pid_(pid) {
43 if (pid_ < 0) {
44 pid_ = getpid();
45 }
46 }
47
~BacktraceMap()48 BacktraceMap::~BacktraceMap() {
49 }
50
FillIn(uint64_t addr,backtrace_map_t * map)51 void BacktraceMap::FillIn(uint64_t addr, backtrace_map_t* map) {
52 ScopedBacktraceMapIteratorLock lock(this);
53 for (auto it = begin(); it != end(); ++it) {
54 const backtrace_map_t* entry = *it;
55 if (addr >= entry->start && addr < entry->end) {
56 *map = *entry;
57 return;
58 }
59 }
60 *map = {};
61 }
62
ParseLine(const char * line,backtrace_map_t * map)63 bool BacktraceMap::ParseLine(const char* line, backtrace_map_t* map) {
64 uint64_t start;
65 uint64_t end;
66 char permissions[5];
67 int name_pos;
68
69 #if defined(__APPLE__)
70 // Mac OS vmmap(1) output:
71 // __TEXT 0009f000-000a1000 [ 8K 8K] r-x/rwx SM=COW /Volumes/android/dalvik-dev/out/host/darwin-x86/bin/libcorkscrew_test\n
72 // 012345678901234567890123456789012345678901234567890123456789
73 // 0 1 2 3 4 5
74 if (sscanf(line, "%*21c %" SCNx64 "-%" SCNx64 " [%*13c] %3c/%*3c SM=%*3c %n",
75 &start, &end, permissions, &name_pos) != 3) {
76 #else
77 // Linux /proc/<pid>/maps lines:
78 // 6f000000-6f01e000 rwxp 00000000 00:0c 16389419 /system/lib/libcomposer.so\n
79 // 012345678901234567890123456789012345678901234567890123456789
80 // 0 1 2 3 4 5
81 if (sscanf(line, "%" SCNx64 "-%" SCNx64 " %4s %*x %*x:%*x %*d %n",
82 &start, &end, permissions, &name_pos) != 3) {
83 #endif
84 return false;
85 }
86
87 map->start = start;
88 map->end = end;
89 map->flags = PROT_NONE;
90 if (permissions[0] == 'r') {
91 map->flags |= PROT_READ;
92 }
93 if (permissions[1] == 'w') {
94 map->flags |= PROT_WRITE;
95 }
96 if (permissions[2] == 'x') {
97 map->flags |= PROT_EXEC;
98 }
99
100 map->name = line+name_pos;
101 if (!map->name.empty() && map->name[map->name.length()-1] == '\n') {
102 map->name.erase(map->name.length()-1);
103 }
104
105 ALOGV("Parsed map: start=%p, end=%p, flags=%x, name=%s",
106 reinterpret_cast<void*>(map->start), reinterpret_cast<void*>(map->end),
107 map->flags, map->name.c_str());
108 return true;
109 }
110
111 bool BacktraceMap::Build() {
112 #if defined(__APPLE__)
113 char cmd[sizeof(pid_t)*3 + sizeof("vmmap -w -resident -submap -allSplitLibs -interleaved ") + 1];
114 #else
115 char path[sizeof(pid_t)*3 + sizeof("/proc//maps") + 1];
116 #endif
117 char line[1024];
118
119 #if defined(__APPLE__)
120 // cmd is guaranteed to always be big enough to hold this string.
121 snprintf(cmd, sizeof(cmd), "vmmap -w -resident -submap -allSplitLibs -interleaved %d", pid_);
122 FILE* fp = popen(cmd, "r");
123 #else
124 // path is guaranteed to always be big enough to hold this string.
125 snprintf(path, sizeof(path), "/proc/%d/maps", pid_);
126 FILE* fp = fopen(path, "r");
127 #endif
128 if (fp == nullptr) {
129 return false;
130 }
131
132 while(fgets(line, sizeof(line), fp)) {
133 backtrace_map_t map;
134 if (ParseLine(line, &map)) {
135 maps_.push_back(map);
136 }
137 }
138 #if defined(__APPLE__)
139 pclose(fp);
140 #else
141 fclose(fp);
142 #endif
143
144 return true;
145 }
146
147 #if defined(__APPLE__)
148 // Corkscrew and libunwind don't compile on the mac, so create a generic
149 // map object.
150 BacktraceMap* BacktraceMap::Create(pid_t pid, bool /*uncached*/) {
151 BacktraceMap* map = new BacktraceMap(pid);
152 if (!map->Build()) {
153 delete map;
154 return nullptr;
155 }
156 return map;
157 }
158 #endif
159