1/* backtrace.h -- Public header file for stack backtrace library.
2 Copyright (C) 2012-2025 Free Software Foundation, Inc.
3 Written by Ian Lance Taylor, Google.
4
5Redistribution and use in source and binary forms, with or without
6modification, are permitted provided that the following conditions are
7met:
8
9 (1) Redistributions of source code must retain the above copyright
10 notice, this list of conditions and the following disclaimer.
11
12 (2) Redistributions in binary form must reproduce the above copyright
13 notice, this list of conditions and the following disclaimer in
14 the documentation and/or other materials provided with the
15 distribution.
16
17 (3) The name of the author may not be used to
18 endorse or promote products derived from this software without
19 specific prior written permission.
20
21THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
24DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
25INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
26(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
27SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
29STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
30IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31POSSIBILITY OF SUCH DAMAGE. */
32
33#ifndef BACKTRACE_H
34#define BACKTRACE_H
35
36#include <stddef.h>
37#include <stdio.h>
38
39/* We want to get a definition for uintptr_t, but we still care about
40 systems that don't have <stdint.h>. */
41#if defined(__GLIBC__) && __GLIBC__ >= 2
42
43#include <stdint.h>
44
45#elif defined(HAVE_STDINT_H)
46
47#include <stdint.h>
48
49#else
50
51/* Systems that don't have <stdint.h> must provide gstdint.h, e.g.,
52 from GCC_HEADER_STDINT in configure.ac. */
53#include "gstdint.h"
54
55#endif
56
57#ifdef __cplusplus
58extern "C" {
59#endif
60
61/* The backtrace state. This struct is intentionally not defined in
62 the public interface. */
63
64struct backtrace_state;
65
66/* The type of the error callback argument to backtrace functions.
67 This function, if not NULL, will be called for certain error cases.
68 The DATA argument is passed to the function that calls this one.
69 The MSG argument is an error message. The ERRNUM argument, if
70 greater than 0, holds an errno value. The MSG buffer may become
71 invalid after this function returns.
72
73 As a special case, the ERRNUM argument will be passed as -1 if no
74 debug info can be found for the executable, or if the debug info
75 exists but has an unsupported version, but the function requires
76 debug info (e.g., backtrace_full, backtrace_pcinfo). The MSG in
77 this case will be something along the lines of "no debug info".
78 Similarly, ERRNUM will be passed as -1 if there is no symbol table,
79 but the function requires a symbol table (e.g., backtrace_syminfo).
80 This may be used as a signal that some other approach should be
81 tried. */
82
83typedef void (*backtrace_error_callback) (void *data, const char *msg,
84 int errnum);
85
86/* Create state information for the backtrace routines. This must be
87 called before any of the other routines, and its return value must
88 be passed to all of the other routines. FILENAME is the path name
89 of the executable file; if it is NULL the library will try
90 system-specific path names. If not NULL, FILENAME must point to a
91 permanent buffer. If THREADED is non-zero the state may be
92 accessed by multiple threads simultaneously, and the library will
93 use appropriate atomic operations. If THREADED is zero the state
94 may only be accessed by one thread at a time. This returns a state
95 pointer on success, NULL on error. If an error occurs, this will
96 call the ERROR_CALLBACK routine.
97
98 Calling this function allocates resources that cannot be freed.
99 There is no backtrace_free_state function. The state is used to
100 cache information that is expensive to recompute. Programs are
101 expected to call this function at most once and to save the return
102 value for all later calls to backtrace functions. */
103
104extern struct backtrace_state *backtrace_create_state (
105 const char *filename, int threaded,
106 backtrace_error_callback error_callback, void *data);
107
108/* The type of the callback argument to the backtrace_full function.
109 DATA is the argument passed to backtrace_full. PC is the program
110 counter. FILENAME is the name of the file containing PC, or NULL
111 if not available. LINENO is the line number in FILENAME containing
112 PC, or 0 if not available. FUNCTION is the name of the function
113 containing PC, or NULL if not available. This should return 0 to
114 continuing tracing. The FILENAME and FUNCTION buffers may become
115 invalid after this function returns. */
116
117typedef int (*backtrace_full_callback) (void *data, uintptr_t pc,
118 const char *filename, int lineno,
119 const char *function);
120
121/* Get a full stack backtrace. SKIP is the number of frames to skip;
122 passing 0 will start the trace with the function calling
123 backtrace_full. DATA is passed to the callback routine. If any
124 call to CALLBACK returns a non-zero value, the stack backtrace
125 stops, and backtrace returns that value; this may be used to limit
126 the number of stack frames desired. If all calls to CALLBACK
127 return 0, backtrace returns 0. The backtrace_full function will
128 make at least one call to either CALLBACK or ERROR_CALLBACK. This
129 function requires debug info for the executable. */
130
131extern int backtrace_full (struct backtrace_state *state, int skip,
132 backtrace_full_callback callback,
133 backtrace_error_callback error_callback,
134 void *data);
135
136/* The type of the callback argument to the backtrace_simple function.
137 DATA is the argument passed to simple_backtrace. PC is the program
138 counter. This should return 0 to continue tracing. */
139
140typedef int (*backtrace_simple_callback) (void *data, uintptr_t pc);
141
142/* Get a simple backtrace. SKIP is the number of frames to skip, as
143 in backtrace. DATA is passed to the callback routine. If any call
144 to CALLBACK returns a non-zero value, the stack backtrace stops,
145 and backtrace_simple returns that value. Otherwise
146 backtrace_simple returns 0. The backtrace_simple function will
147 make at least one call to either CALLBACK or ERROR_CALLBACK. This
148 function does not require any debug info for the executable. */
149
150extern int backtrace_simple (struct backtrace_state *state, int skip,
151 backtrace_simple_callback callback,
152 backtrace_error_callback error_callback,
153 void *data);
154
155/* Print the current backtrace in a user readable format to a FILE.
156 SKIP is the number of frames to skip, as in backtrace_full. Any
157 error messages are printed to stderr. This function requires debug
158 info for the executable. */
159
160extern void backtrace_print (struct backtrace_state *state, int skip, FILE *);
161
162/* Given PC, a program counter in the current program, call the
163 callback function with filename, line number, and function name
164 information. This will normally call the callback function exactly
165 once. However, if the PC happens to describe an inlined call, and
166 the debugging information contains the necessary information, then
167 this may call the callback function multiple times. This will make
168 at least one call to either CALLBACK or ERROR_CALLBACK. This
169 returns the first non-zero value returned by CALLBACK, or 0. */
170
171extern int backtrace_pcinfo (struct backtrace_state *state, uintptr_t pc,
172 backtrace_full_callback callback,
173 backtrace_error_callback error_callback,
174 void *data);
175
176/* The type of the callback argument to backtrace_syminfo. DATA and
177 PC are the arguments passed to backtrace_syminfo. SYMNAME is the
178 name of the symbol for the corresponding code. SYMVAL is the
179 value and SYMSIZE is the size of the symbol. SYMNAME will be NULL
180 if no error occurred but the symbol could not be found. */
181
182typedef void (*backtrace_syminfo_callback) (void *data, uintptr_t pc,
183 const char *symname,
184 uintptr_t symval,
185 uintptr_t symsize);
186
187/* Given ADDR, an address or program counter in the current program,
188 call the callback information with the symbol name and value
189 describing the function or variable in which ADDR may be found.
190 This will call either CALLBACK or ERROR_CALLBACK exactly once.
191 This returns 1 on success, 0 on failure. This function requires
192 the symbol table but does not require the debug info. Note that if
193 the symbol table is present but ADDR could not be found in the
194 table, CALLBACK will be called with a NULL SYMNAME argument.
195 Returns 1 on success, 0 on error. */
196
197extern int backtrace_syminfo (struct backtrace_state *state, uintptr_t addr,
198 backtrace_syminfo_callback callback,
199 backtrace_error_callback error_callback,
200 void *data);
201
202#ifdef __cplusplus
203} /* End extern "C". */
204#endif
205
206#endif
207

source code of libbacktrace/backtrace.h