1/* print.c -- Print the current backtrace.
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#include "config.h"
34
35#include <stdio.h>
36#include <string.h>
37#include <sys/types.h>
38
39#include "backtrace.h"
40#include "internal.h"
41
42/* Passed to callbacks. */
43
44struct print_data
45{
46 struct backtrace_state *state;
47 FILE *f;
48};
49
50/* Print errors to stderr. */
51
52static void
53error_callback (void *data, const char *msg, int errnum)
54{
55 struct print_data *pdata = (struct print_data *) data;
56
57 if (pdata->state->filename != NULL)
58 fprintf (stderr, format: "%s: ", pdata->state->filename);
59 fprintf (stderr, format: "libbacktrace: %s", msg);
60 if (errnum > 0)
61 fprintf (stderr, format: ": %s", strerror (errnum: errnum));
62 fputc (c: '\n', stderr);
63}
64
65/* Print one level of a backtrace if we couldn't get a file or function name.
66 Use syminfo to try to get a symbol name. */
67
68static void print_syminfo_callback (void *data, uintptr_t pc,
69 const char *symname, uintptr_t symval,
70 uintptr_t symsize ATTRIBUTE_UNUSED)
71{
72 struct print_data *pdata = (struct print_data *) data;
73
74 if (symname == NULL)
75 fprintf (stream: pdata->f, format: "0x%lx ???\n\t???:0\n", (unsigned long) pc);
76 else
77 fprintf (stream: pdata->f, format: "0x%lx ???\n\t%s+0x%lx:0\n",
78 (unsigned long) pc,
79 symname,
80 (unsigned long) (pc - symval));
81}
82
83/* Print one level of a backtrace. */
84
85static int
86print_callback (void *data, uintptr_t pc, const char *filename, int lineno,
87 const char *function)
88{
89 struct print_data *pdata = (struct print_data *) data;
90
91 if (function == NULL && filename == NULL)
92 {
93 backtrace_syminfo (state: pdata->state, addr: pc, callback: print_syminfo_callback,
94 error_callback, data);
95 return 0;
96 }
97
98 fprintf (stream: pdata->f, format: "0x%lx %s\n\t%s:%d\n",
99 (unsigned long) pc,
100 function == NULL ? "???" : function,
101 filename == NULL ? "???" : filename,
102 lineno);
103 return 0;
104}
105
106/* Print a backtrace. */
107
108void __attribute__((noinline))
109backtrace_print (struct backtrace_state *state, int skip, FILE *f)
110{
111 struct print_data data;
112
113 data.state = state;
114 data.f = f;
115 backtrace_full (state, skip: skip + 1, callback: print_callback, error_callback,
116 data: (void *) &data);
117}
118

source code of libbacktrace/print.c