1 // Copyright 2012 The Chromium Authors
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/memory/raw_ptr.h"
16 #include "base/strings/strcat.h"
17 #include "base/strings/stringprintf.h"
18 #include "base/threading/thread_restrictions.h"
19
20 #ifdef __LP64__
21 #define FMT_ADDR "0x%016lx"
22 #else
23 #define FMT_ADDR "0x%08x"
24 #endif
25
26 namespace {
27
28 struct StackCrawlState {
StackCrawlState__anon29c001190111::StackCrawlState29 StackCrawlState(uintptr_t* frames, size_t max_depth)
30 : frames(frames),
31 frame_count(0),
32 max_depth(max_depth),
33 have_skipped_self(false) {}
34
35 raw_ptr<uintptr_t, AllowPtrArithmetic> frames;
36 size_t frame_count;
37 size_t max_depth;
38 bool have_skipped_self;
39 };
40
TraceStackFrame(_Unwind_Context * context,void * arg)41 _Unwind_Reason_Code TraceStackFrame(_Unwind_Context* context, void* arg) {
42 StackCrawlState* state = static_cast<StackCrawlState*>(arg);
43 uintptr_t ip = _Unwind_GetIP(context);
44
45 // The first stack frame is this function itself. Skip it.
46 if (ip != 0 && !state->have_skipped_self) {
47 state->have_skipped_self = true;
48 return _URC_NO_REASON;
49 }
50
51 state->frames[state->frame_count++] = ip;
52 if (state->frame_count >= state->max_depth)
53 return _URC_END_OF_STACK;
54 return _URC_NO_REASON;
55 }
56
EndsWith(const std::string & s,const std::string & suffix)57 bool EndsWith(const std::string& s, const std::string& suffix) {
58 return s.size() >= suffix.size() &&
59 s.substr(s.size() - suffix.size(), suffix.size()) == suffix;
60 }
61
62 } // namespace
63
64 namespace base {
65 namespace debug {
66
EnableInProcessStackDumping()67 bool EnableInProcessStackDumping() {
68 // When running in an application, our code typically expects SIGPIPE
69 // to be ignored. Therefore, when testing that same code, it should run
70 // with SIGPIPE ignored as well.
71 // TODO(phajdan.jr): De-duplicate this SIGPIPE code.
72 struct sigaction action;
73 memset(&action, 0, sizeof(action));
74 action.sa_handler = SIG_IGN;
75 sigemptyset(&action.sa_mask);
76 return (sigaction(SIGPIPE, &action, NULL) == 0);
77 }
78
CollectStackTrace(const void ** trace,size_t count)79 size_t CollectStackTrace(const void** trace, size_t count) {
80 StackCrawlState state(reinterpret_cast<uintptr_t*>(trace), count);
81 _Unwind_Backtrace(&TraceStackFrame, &state);
82 return state.frame_count;
83 }
84
85 // static
PrintMessageWithPrefix(cstring_view prefix_string,cstring_view message)86 void StackTrace::PrintMessageWithPrefix(cstring_view prefix_string,
87 cstring_view message) {
88 if (!prefix_string.empty()) {
89 __android_log_write(ANDROID_LOG_ERROR, "chromium",
90 StrCat({prefix_string, message}).c_str());
91 } else {
92 __android_log_write(ANDROID_LOG_ERROR, "chromium", message.c_str());
93 }
94 }
95
PrintWithPrefixImpl(cstring_view prefix_string) const96 void StackTrace::PrintWithPrefixImpl(cstring_view prefix_string) const {
97 std::string backtrace = ToStringWithPrefix(prefix_string);
98 __android_log_write(ANDROID_LOG_ERROR, "chromium", backtrace.c_str());
99 }
100
101 // NOTE: Native libraries in APKs are stripped before installing. Print out the
102 // relocatable address and library names so host computers can use tools to
103 // symbolize and demangle (e.g., addr2line, c++filt).
OutputToStreamWithPrefixImpl(std::ostream * os,cstring_view prefix_string) const104 void StackTrace::OutputToStreamWithPrefixImpl(
105 std::ostream* os,
106 cstring_view prefix_string) const {
107 std::string proc_maps;
108 std::vector<MappedMemoryRegion> regions;
109 // Allow IO to read /proc/self/maps. Reading this file doesn't hit the disk
110 // since it lives in procfs, and this is currently used to print a stack trace
111 // on fatal log messages in debug builds only. If the restriction is enabled
112 // then it will recursively trigger fatal failures when this enters on the
113 // UI thread.
114 base::ScopedAllowBlocking scoped_allow_blocking;
115 if (!ReadProcMaps(&proc_maps)) {
116 __android_log_write(
117 ANDROID_LOG_ERROR, "chromium", "Failed to read /proc/self/maps");
118 } else if (!ParseProcMaps(proc_maps, ®ions)) {
119 __android_log_write(
120 ANDROID_LOG_ERROR, "chromium", "Failed to parse /proc/self/maps");
121 }
122
123 for (size_t i = 0; i < count_; ++i) {
124 // Subtract one as return address of function may be in the next
125 // function when a function is annotated as noreturn.
126 uintptr_t address = reinterpret_cast<uintptr_t>(trace_[i]) - 1;
127
128 std::vector<MappedMemoryRegion>::iterator iter = regions.begin();
129 while (iter != regions.end()) {
130 if (address >= iter->start && address < iter->end &&
131 !iter->path.empty()) {
132 break;
133 }
134 ++iter;
135 }
136
137 *os << prefix_string;
138
139 // Adjust absolute address to be an offset within the mapped region, to
140 // match the format dumped by Android's crash output.
141 if (iter != regions.end()) {
142 address -= iter->start;
143 }
144
145 // The format below intentionally matches that of Android's debuggerd
146 // output. This simplifies decoding by scripts such as stack.py.
147 *os << base::StringPrintf("#%02zd pc " FMT_ADDR " ", i, address);
148
149 if (iter != regions.end()) {
150 *os << base::StringPrintf("%s", iter->path.c_str());
151 if (EndsWith(iter->path, ".apk")) {
152 *os << base::StringPrintf(" (offset 0x%llx)", iter->offset);
153 }
154 } else {
155 *os << "<unknown>";
156 }
157
158 *os << "\n";
159 }
160 }
161
162 } // namespace debug
163 } // namespace base
164