1/* backtrace.h -- Public header file for stack backtrace library.
2 Copyright (C) 2012-2017 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, but the function
75 requires debug info (e.g., backtrace_full, backtrace_pcinfo). The
76 MSG in this case will be something along the lines of "no debug
77 info". Similarly, ERRNUM will be passed as -1 if there is no
78 symbol table, but the function requires a symbol table (e.g.,
79 backtrace_syminfo). This may be used as a signal that some other
80 approach should be tried. */
81
82typedef void (*backtrace_error_callback) (void *data, const char *msg,
83 int errnum);
84
85/* Create state information for the backtrace routines. This must be
86 called before any of the other routines, and its return value must
87 be passed to all of the other routines. FILENAME is the path name
88 of the executable file; if it is NULL the library will try
89 system-specific path names. If not NULL, FILENAME must point to a
90 permanent buffer. If THREADED is non-zero the state may be
91 accessed by multiple threads simultaneously, and the library will
92 use appropriate atomic operations. If THREADED is zero the state
93 may only be accessed by one thread at a time. This returns a state
94 pointer on success, NULL on error. If an error occurs, this will
95 call the ERROR_CALLBACK routine. */
96
97extern struct backtrace_state *backtrace_create_state (
98 const char *filename, int threaded,
99 backtrace_error_callback error_callback, void *data);
100
101/* The type of the callback argument to the backtrace_full function.
102 DATA is the argument passed to backtrace_full. PC is the program
103 counter. FILENAME is the name of the file containing PC, or NULL
104 if not available. LINENO is the line number in FILENAME containing
105 PC, or 0 if not available. FUNCTION is the name of the function
106 containing PC, or NULL if not available. This should return 0 to
107 continuing tracing. The FILENAME and FUNCTION buffers may become
108 invalid after this function returns. */
109
110typedef int (*backtrace_full_callback) (void *data, uintptr_t pc,
111 const char *filename, int lineno,
112 const char *function);
113
114/* Get a full stack backtrace. SKIP is the number of frames to skip;
115 passing 0 will start the trace with the function calling
116 backtrace_full. DATA is passed to the callback routine. If any
117 call to CALLBACK returns a non-zero value, the stack backtrace
118 stops, and backtrace returns that value; this may be used to limit
119 the number of stack frames desired. If all calls to CALLBACK
120 return 0, backtrace returns 0. The backtrace_full function will
121 make at least one call to either CALLBACK or ERROR_CALLBACK. This
122 function requires debug info for the executable. */
123
124extern int backtrace_full (struct backtrace_state *state, int skip,
125 backtrace_full_callback callback,
126 backtrace_error_callback error_callback,
127 void *data);
128
129/* The type of the callback argument to the backtrace_simple function.
130 DATA is the argument passed to simple_backtrace. PC is the program
131 counter. This should return 0 to continue tracing. */
132
133typedef int (*backtrace_simple_callback) (void *data, uintptr_t pc);
134
135/* Get a simple backtrace. SKIP is the number of frames to skip, as
136 in backtrace. DATA is passed to the callback routine. If any call
137 to CALLBACK returns a non-zero value, the stack backtrace stops,
138 and backtrace_simple returns that value. Otherwise
139 backtrace_simple returns 0. The backtrace_simple function will
140 make at least one call to either CALLBACK or ERROR_CALLBACK. This
141 function does not require any debug info for the executable. */
142
143extern int backtrace_simple (struct backtrace_state *state, int skip,
144 backtrace_simple_callback callback,
145 backtrace_error_callback error_callback,
146 void *data);
147
148/* Print the current backtrace in a user readable format to a FILE.
149 SKIP is the number of frames to skip, as in backtrace_full. Any
150 error messages are printed to stderr. This function requires debug
151 info for the executable. */
152
153extern void backtrace_print (struct backtrace_state *state, int skip, FILE *);
154
155/* Given PC, a program counter in the current program, call the
156 callback function with filename, line number, and function name
157 information. This will normally call the callback function exactly
158 once. However, if the PC happens to describe an inlined call, and
159 the debugging information contains the necessary information, then
160 this may call the callback function multiple times. This will make
161 at least one call to either CALLBACK or ERROR_CALLBACK. This
162 returns the first non-zero value returned by CALLBACK, or 0. */
163
164extern int backtrace_pcinfo (struct backtrace_state *state, uintptr_t pc,
165 backtrace_full_callback callback,
166 backtrace_error_callback error_callback,
167 void *data);
168
169/* The type of the callback argument to backtrace_syminfo. DATA and
170 PC are the arguments passed to backtrace_syminfo. SYMNAME is the
171 name of the symbol for the corresponding code. SYMVAL is the
172 value and SYMSIZE is the size of the symbol. SYMNAME will be NULL
173 if no error occurred but the symbol could not be found. */
174
175typedef void (*backtrace_syminfo_callback) (void *data, uintptr_t pc,
176 const char *symname,
177 uintptr_t symval,
178 uintptr_t symsize);
179
180/* Given ADDR, an address or program counter in the current program,
181 call the callback information with the symbol name and value
182 describing the function or variable in which ADDR may be found.
183 This will call either CALLBACK or ERROR_CALLBACK exactly once.
184 This returns 1 on success, 0 on failure. This function requires
185 the symbol table but does not require the debug info. Note that if
186 the symbol table is present but ADDR could not be found in the
187 table, CALLBACK will be called with a NULL SYMNAME argument.
188 Returns 1 on success, 0 on error. */
189
190extern int backtrace_syminfo (struct backtrace_state *state, uintptr_t addr,
191 backtrace_syminfo_callback callback,
192 backtrace_error_callback error_callback,
193 void *data);
194
195#ifdef __cplusplus
196} /* End extern "C". */
197#endif
198
199#endif
200