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 #include <ostream>
11
12 #include "base/debug/proc_maps_linux.h"
13 #include "base/strings/stringprintf.h"
14 #include "base/threading/thread_restrictions.h"
15
16 #ifdef __LP64__
17 #define FMT_ADDR "0x%016lx"
18 #else
19 #define FMT_ADDR "0x%08x"
20 #endif
21
22 namespace {
23
24 struct StackCrawlState {
StackCrawlState__anon925f3f030111::StackCrawlState25 StackCrawlState(uintptr_t* frames, size_t max_depth)
26 : frames(frames),
27 frame_count(0),
28 max_depth(max_depth),
29 have_skipped_self(false) {}
30
31 uintptr_t* frames;
32 size_t frame_count;
33 size_t max_depth;
34 bool have_skipped_self;
35 };
36
TraceStackFrame(_Unwind_Context * context,void * arg)37 _Unwind_Reason_Code TraceStackFrame(_Unwind_Context* context, void* arg) {
38 StackCrawlState* state = static_cast<StackCrawlState*>(arg);
39 uintptr_t ip = _Unwind_GetIP(context);
40
41 // The first stack frame is this function itself. Skip it.
42 if (ip != 0 && !state->have_skipped_self) {
43 state->have_skipped_self = true;
44 return _URC_NO_REASON;
45 }
46
47 state->frames[state->frame_count++] = ip;
48 if (state->frame_count >= state->max_depth)
49 return _URC_END_OF_STACK;
50 return _URC_NO_REASON;
51 }
52
53 } // namespace
54
55 namespace base {
56 namespace debug {
57
EnableInProcessStackDumping()58 bool EnableInProcessStackDumping() {
59 // When running in an application, our code typically expects SIGPIPE
60 // to be ignored. Therefore, when testing that same code, it should run
61 // with SIGPIPE ignored as well.
62 // TODO(phajdan.jr): De-duplicate this SIGPIPE code.
63 struct sigaction action;
64 memset(&action, 0, sizeof(action));
65 action.sa_handler = SIG_IGN;
66 sigemptyset(&action.sa_mask);
67 return (sigaction(SIGPIPE, &action, NULL) == 0);
68 }
69
StackTrace()70 StackTrace::StackTrace() {
71 StackCrawlState state(reinterpret_cast<uintptr_t*>(trace_), kMaxTraces);
72 _Unwind_Backtrace(&TraceStackFrame, &state);
73 count_ = state.frame_count;
74 }
75
Print() const76 void StackTrace::Print() const {
77 std::string backtrace = ToString();
78 __android_log_write(ANDROID_LOG_ERROR, "chromium", backtrace.c_str());
79 }
80
81 // NOTE: Native libraries in APKs are stripped before installing. Print out the
82 // relocatable address and library names so host computers can use tools to
83 // symbolize and demangle (e.g., addr2line, c++filt).
OutputToStream(std::ostream * os) const84 void StackTrace::OutputToStream(std::ostream* os) const {
85 std::string proc_maps;
86 std::vector<MappedMemoryRegion> regions;
87 // Allow IO to read /proc/self/maps. Reading this file doesn't hit the disk
88 // since it lives in procfs, and this is currently used to print a stack trace
89 // on fatal log messages in debug builds only. If the restriction is enabled
90 // then it will recursively trigger fatal failures when this enters on the
91 // UI thread.
92 base::ThreadRestrictions::ScopedAllowIO allow_io;
93 if (!ReadProcMaps(&proc_maps)) {
94 __android_log_write(
95 ANDROID_LOG_ERROR, "chromium", "Failed to read /proc/self/maps");
96 } else if (!ParseProcMaps(proc_maps, ®ions)) {
97 __android_log_write(
98 ANDROID_LOG_ERROR, "chromium", "Failed to parse /proc/self/maps");
99 }
100
101 for (size_t i = 0; i < count_; ++i) {
102 // Subtract one as return address of function may be in the next
103 // function when a function is annotated as noreturn.
104 uintptr_t address = reinterpret_cast<uintptr_t>(trace_[i]) - 1;
105
106 std::vector<MappedMemoryRegion>::iterator iter = regions.begin();
107 while (iter != regions.end()) {
108 if (address >= iter->start && address < iter->end &&
109 !iter->path.empty()) {
110 break;
111 }
112 ++iter;
113 }
114
115 *os << base::StringPrintf("#%02zd " FMT_ADDR " ", i, address);
116
117 if (iter != regions.end()) {
118 uintptr_t rel_pc = address - iter->start + iter->offset;
119 const char* path = iter->path.c_str();
120 *os << base::StringPrintf("%s+" FMT_ADDR, path, rel_pc);
121 } else {
122 *os << "<unknown>";
123 }
124
125 *os << "\n";
126 }
127 }
128
129 } // namespace debug
130 } // namespace base
131