backtrace.h revision 19b39f371be5250e7b9e88016be1e5e665367b3f 
1/*
2 * Copyright (C) 2011 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/* A stack unwinder. */
18
19#ifndef _CORKSCREW_BACKTRACE_H
20#define _CORKSCREW_BACKTRACE_H
21
22#ifdef __cplusplus
23extern "C" {
24#endif
25
26#include <sys/types.h>
27#include <corkscrew/ptrace.h>
28#include <corkscrew/map_info.h>
29#include <corkscrew/symbol_table.h>
30
31/*
32 * Describes a single frame of a backtrace.
33 */
34typedef struct {
35    uintptr_t absolute_pc;     /* absolute PC offset */
36    uintptr_t stack_top;       /* top of stack for this frame */
37    size_t stack_size;         /* size of this stack frame */
38} backtrace_frame_t;
39
40/*
41 * Describes the symbols associated with a backtrace frame.
42 */
43typedef struct {
44    uintptr_t relative_pc;       /* relative frame PC offset from the start of the library,
45                                    or the absolute PC if the library is unknown */
46    uintptr_t relative_symbol_addr; /* relative offset of the symbol from the start of the
47                                    library or 0 if the library is unknown */
48    char* map_name;              /* executable or library name, or NULL if unknown */
49    char* symbol_name;           /* symbol name, or NULL if unknown */
50    char* demangled_name;        /* demangled symbol name, or NULL if unknown */
51} backtrace_symbol_t;
52
53/*
54 * Unwinds the call stack for the current thread of execution.
55 * Populates the backtrace array with the program counters from the call stack.
56 * Returns the number of frames collected, or -1 if an error occurred.
57 */
58ssize_t unwind_backtrace(backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth);
59
60/*
61 * Unwinds the call stack for a thread within this process.
62 * Populates the backtrace array with the program counters from the call stack.
63 * Returns the number of frames collected, or -1 if an error occurred.
64 *
65 * The task is briefly suspended while the backtrace is being collected.
66 */
67ssize_t unwind_backtrace_thread(pid_t tid, backtrace_frame_t* backtrace,
68        size_t ignore_depth, size_t max_depth);
69
70/*
71 * Unwinds the call stack of a task within a remote process using ptrace().
72 * Populates the backtrace array with the program counters from the call stack.
73 * Returns the number of frames collected, or -1 if an error occurred.
74 */
75ssize_t unwind_backtrace_ptrace(pid_t tid, const ptrace_context_t* context,
76        backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth);
77
78/*
79 * Gets the symbols for each frame of a backtrace.
80 * The symbols array must be big enough to hold one symbol record per frame.
81 * The symbols must later be freed using free_backtrace_symbols.
82 */
83void get_backtrace_symbols(const backtrace_frame_t* backtrace, size_t frames,
84        backtrace_symbol_t* backtrace_symbols);
85
86/*
87 * Gets the symbols for each frame of a backtrace from a remote process.
88 * The symbols array must be big enough to hold one symbol record per frame.
89 * The symbols must later be freed using free_backtrace_symbols.
90 */
91void get_backtrace_symbols_ptrace(const ptrace_context_t* context,
92        const backtrace_frame_t* backtrace, size_t frames,
93        backtrace_symbol_t* backtrace_symbols);
94
95/*
96 * Frees the storage associated with backtrace symbols.
97 */
98void free_backtrace_symbols(backtrace_symbol_t* backtrace_symbols, size_t frames);
99
100enum {
101    // A hint for how big to make the line buffer for format_backtrace_line
102    MAX_BACKTRACE_LINE_LENGTH = 800,
103};
104
105/**
106 * Formats a line from a backtrace as a zero-terminated string into the specified buffer.
107 */
108void format_backtrace_line(unsigned frameNumber, const backtrace_frame_t* frame,
109        const backtrace_symbol_t* symbol, char* buffer, size_t bufferSize);
110
111#ifdef __cplusplus
112}
113#endif
114
115#endif // _CORKSCREW_BACKTRACE_H
116