1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/debug/stack_trace.h"
6
7 #include <android/log.h>
8 #include <stddef.h>
9 #include <unwind.h>
10
11 #include <algorithm>
12 #include <ostream>
13
14 #include "base/debug/proc_maps_linux.h"
15 #include "base/stl_util.h"
16 #include "base/strings/stringprintf.h"
17 #include "base/threading/thread_restrictions.h"
18
19 #ifdef __LP64__
20 #define FMT_ADDR "0x%016lx"
21 #else
22 #define FMT_ADDR "0x%08x"
23 #endif
24
25 namespace {
26
27 struct StackCrawlState {
StackCrawlState__anon8509b2f80111::StackCrawlState28 StackCrawlState(uintptr_t* frames, size_t max_depth)
29 : frames(frames),
30 frame_count(0),
31 max_depth(max_depth),
32 have_skipped_self(false) {}
33
34 uintptr_t* frames;
35 size_t frame_count;
36 size_t max_depth;
37 bool have_skipped_self;
38 };
39
TraceStackFrame(_Unwind_Context * context,void * arg)40 _Unwind_Reason_Code TraceStackFrame(_Unwind_Context* context, void* arg) {
41 StackCrawlState* state = static_cast<StackCrawlState*>(arg);
42 uintptr_t ip = _Unwind_GetIP(context);
43
44 // The first stack frame is this function itself. Skip it.
45 if (ip != 0 && !state->have_skipped_self) {
46 state->have_skipped_self = true;
47 return _URC_NO_REASON;
48 }
49
50 state->frames[state->frame_count++] = ip;
51 if (state->frame_count >= state->max_depth)
52 return _URC_END_OF_STACK;
53 return _URC_NO_REASON;
54 }
55
EndsWith(const std::string & s,const std::string & suffix)56 bool EndsWith(const std::string& s, const std::string& suffix) {
57 return s.size() >= suffix.size() &&
58 s.substr(s.size() - suffix.size(), suffix.size()) == suffix;
59 }
60
61 } // namespace
62
63 namespace base {
64 namespace debug {
65
EnableInProcessStackDumping()66 bool EnableInProcessStackDumping() {
67 // When running in an application, our code typically expects SIGPIPE
68 // to be ignored. Therefore, when testing that same code, it should run
69 // with SIGPIPE ignored as well.
70 // TODO(phajdan.jr): De-duplicate this SIGPIPE code.
71 struct sigaction action;
72 memset(&action, 0, sizeof(action));
73 action.sa_handler = SIG_IGN;
74 sigemptyset(&action.sa_mask);
75 return (sigaction(SIGPIPE, &action, NULL) == 0);
76 }
77
CollectStackTrace(void ** trace,size_t count)78 size_t CollectStackTrace(void** trace, size_t count) {
79 StackCrawlState state(reinterpret_cast<uintptr_t*>(trace), count);
80 _Unwind_Backtrace(&TraceStackFrame, &state);
81 return state.frame_count;
82 }
83
PrintWithPrefix(const char * prefix_string) const84 void StackTrace::PrintWithPrefix(const char* prefix_string) const {
85 std::string backtrace = ToStringWithPrefix(prefix_string);
86 __android_log_write(ANDROID_LOG_ERROR, "chromium", backtrace.c_str());
87 }
88
89 // NOTE: Native libraries in APKs are stripped before installing. Print out the
90 // relocatable address and library names so host computers can use tools to
91 // symbolize and demangle (e.g., addr2line, c++filt).
OutputToStreamWithPrefix(std::ostream * os,const char * prefix_string) const92 void StackTrace::OutputToStreamWithPrefix(std::ostream* os,
93 const char* prefix_string) const {
94 std::string proc_maps;
95 std::vector<MappedMemoryRegion> regions;
96 // Allow IO to read /proc/self/maps. Reading this file doesn't hit the disk
97 // since it lives in procfs, and this is currently used to print a stack trace
98 // on fatal log messages in debug builds only. If the restriction is enabled
99 // then it will recursively trigger fatal failures when this enters on the
100 // UI thread.
101 base::ThreadRestrictions::ScopedAllowIO allow_io;
102 if (!ReadProcMaps(&proc_maps)) {
103 __android_log_write(
104 ANDROID_LOG_ERROR, "chromium", "Failed to read /proc/self/maps");
105 } else if (!ParseProcMaps(proc_maps, ®ions)) {
106 __android_log_write(
107 ANDROID_LOG_ERROR, "chromium", "Failed to parse /proc/self/maps");
108 }
109
110 for (size_t i = 0; i < count_; ++i) {
111 // Subtract one as return address of function may be in the next
112 // function when a function is annotated as noreturn.
113 uintptr_t address = reinterpret_cast<uintptr_t>(trace_[i]) - 1;
114
115 std::vector<MappedMemoryRegion>::iterator iter = regions.begin();
116 while (iter != regions.end()) {
117 if (address >= iter->start && address < iter->end &&
118 !iter->path.empty()) {
119 break;
120 }
121 ++iter;
122 }
123
124 if (prefix_string)
125 *os << prefix_string;
126
127 // Adjust absolute address to be an offset within the mapped region, to
128 // match the format dumped by Android's crash output.
129 if (iter != regions.end()) {
130 address -= iter->start;
131 }
132
133 // The format below intentionally matches that of Android's debuggerd
134 // output. This simplifies decoding by scripts such as stack.py.
135 *os << base::StringPrintf("#%02zd pc " FMT_ADDR " ", i, address);
136
137 if (iter != regions.end()) {
138 *os << base::StringPrintf("%s", iter->path.c_str());
139 if (EndsWith(iter->path, ".apk")) {
140 *os << base::StringPrintf(" (offset 0x%llx)", iter->offset);
141 }
142 } else {
143 *os << "<unknown>";
144 }
145
146 *os << "\n";
147 }
148 }
149
150 } // namespace debug
151 } // namespace base
152