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 #if defined(__linux__)
32 #include <procinfo/process_map.h>
33 #endif
34
35 using android::base::StringPrintf;
36
Name() const37 std::string backtrace_map_t::Name() const {
38 if (!name.empty()) return name;
39 if (start == 0 && end == 0) return "";
40 return StringPrintf("<anonymous:%" PRIPTR ">", start);
41 }
42
BacktraceMap(pid_t pid)43 BacktraceMap::BacktraceMap(pid_t pid) : pid_(pid) {
44 if (pid_ < 0) {
45 pid_ = getpid();
46 }
47 }
48
~BacktraceMap()49 BacktraceMap::~BacktraceMap() {}
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
63 #if defined(__APPLE__)
ParseLine(const char * line,backtrace_map_t * map)64 static bool ParseLine(const char* line, backtrace_map_t* map) {
65 uint64_t start;
66 uint64_t end;
67 char permissions[5];
68 int name_pos;
69
70 // Mac OS vmmap(1) output:
71 // __TEXT 0009f000-000a1000 [ 8K 8K] r-x/rwx SM=COW
72 // /Volumes/android/dalvik-dev/out/host/darwin-x86/bin/libcorkscrew_test\n
73 // 012345678901234567890123456789012345678901234567890123456789
74 // 0 1 2 3 4 5
75 if (sscanf(line, "%*21c %" SCNx64 "-%" SCNx64 " [%*13c] %3c/%*3c SM=%*3c %n", &start, &end,
76 permissions, &name_pos) != 3) {
77 return false;
78 }
79
80 map->start = start;
81 map->end = end;
82 map->flags = PROT_NONE;
83 if (permissions[0] == 'r') {
84 map->flags |= PROT_READ;
85 }
86 if (permissions[1] == 'w') {
87 map->flags |= PROT_WRITE;
88 }
89 if (permissions[2] == 'x') {
90 map->flags |= PROT_EXEC;
91 }
92
93 map->name = line + name_pos;
94 if (!map->name.empty() && map->name[map->name.length() - 1] == '\n') {
95 map->name.erase(map->name.length() - 1);
96 }
97
98 ALOGV("Parsed map: start=%p, end=%p, flags=%x, name=%s", reinterpret_cast<void*>(map->start),
99 reinterpret_cast<void*>(map->end), map->flags, map->name.c_str());
100 return true;
101 }
102 #endif // defined(__APPLE__)
103
Build()104 bool BacktraceMap::Build() {
105 #if defined(__APPLE__)
106 char
107 cmd[sizeof(pid_t) * 3 + sizeof("vmmap -w -resident -submap -allSplitLibs -interleaved ") + 1];
108 char line[1024];
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 if (fp == nullptr) {
113 return false;
114 }
115
116 while (fgets(line, sizeof(line), fp)) {
117 backtrace_map_t map;
118 if (ParseLine(line, &map)) {
119 maps_.push_back(map);
120 }
121 }
122 pclose(fp);
123 return true;
124 #else
125 return android::procinfo::ReadProcessMaps(
126 pid_, [&](uint64_t start, uint64_t end, uint16_t flags, uint64_t, ino_t, const char* name) {
127 maps_.resize(maps_.size() + 1);
128 backtrace_map_t& map = maps_.back();
129 map.start = start;
130 map.end = end;
131 map.flags = flags;
132 map.name = name;
133 });
134 #endif
135 }
136
137 #if defined(__APPLE__)
138 // Corkscrew and libunwind don't compile on the mac, so create a generic
139 // map object.
Create(pid_t pid,bool)140 BacktraceMap* BacktraceMap::Create(pid_t pid, bool /*uncached*/) {
141 BacktraceMap* map = new BacktraceMap(pid);
142 if (!map->Build()) {
143 delete map;
144 return nullptr;
145 }
146 return map;
147 }
148 #endif
149