1/* Write formatted list with names for addresses in backtrace to a file.
2 Copyright (C) 1998-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#include <execinfo.h>
21#include <string.h>
22#include <sys/uio.h>
23
24#include <_itoa.h>
25#include <ldsodefs.h>
26
27#if __ELF_NATIVE_CLASS == 32
28# define WORD_WIDTH 8
29#else
30/* We assume 64bits. */
31# define WORD_WIDTH 16
32#endif
33
34
35void
36__backtrace_symbols_fd (void *const *array, int size, int fd)
37{
38 struct iovec iov[9];
39 int cnt;
40
41 for (cnt = 0; cnt < size; ++cnt)
42 {
43 char buf[WORD_WIDTH];
44 char buf2[WORD_WIDTH];
45 Dl_info info;
46 struct link_map *map;
47 size_t last = 0;
48
49 if (_dl_addr (array[cnt], &info, &map, NULL)
50 && info.dli_fname != NULL && info.dli_fname[0] != '\0')
51 {
52 /* Name of the file. */
53 iov[0].iov_base = (void *) info.dli_fname;
54 iov[0].iov_len = strlen (info.dli_fname);
55 last = 1;
56
57 if (info.dli_sname != NULL || map->l_addr != 0)
58 {
59 size_t diff;
60
61 iov[last].iov_base = (void *) "(";
62 iov[last].iov_len = 1;
63 ++last;
64
65 if (info.dli_sname != NULL)
66 {
67 /* We have a symbol name. */
68 iov[last].iov_base = (void *) info.dli_sname;
69 iov[last].iov_len = strlen (info.dli_sname);
70 ++last;
71 }
72 else
73 /* We have no symbol, so describe it as relative to the file.
74 The load bias is more useful to the user than the load
75 address. The use of these addresses is to calculate an
76 address in the ELF file, so its prelinked bias is not
77 something we want to subtract out. */
78 info.dli_saddr = (void *) map->l_addr;
79
80 if (array[cnt] >= (void *) info.dli_saddr)
81 {
82 iov[last].iov_base = (void *) "+0x";
83 diff = array[cnt] - info.dli_saddr;
84 }
85 else
86 {
87 iov[last].iov_base = (void *) "-0x";
88 diff = info.dli_saddr - array[cnt];
89 }
90 iov[last].iov_len = 3;
91 ++last;
92
93 iov[last].iov_base = _itoa_word ((unsigned long int) diff,
94 &buf2[WORD_WIDTH], 16, 0);
95 iov[last].iov_len = (&buf2[WORD_WIDTH]
96 - (char *) iov[last].iov_base);
97 ++last;
98
99 iov[last].iov_base = (void *) ")";
100 iov[last].iov_len = 1;
101 ++last;
102 }
103 }
104
105 iov[last].iov_base = (void *) "[0x";
106 iov[last].iov_len = 3;
107 ++last;
108
109 iov[last].iov_base = _itoa_word ((unsigned long int) array[cnt],
110 &buf[WORD_WIDTH], 16, 0);
111 iov[last].iov_len = &buf[WORD_WIDTH] - (char *) iov[last].iov_base;
112 ++last;
113
114 iov[last].iov_base = (void *) "]\n";
115 iov[last].iov_len = 2;
116 ++last;
117
118 __writev (fd, iov, last);
119 }
120}
121weak_alias (__backtrace_symbols_fd, backtrace_symbols_fd)
122libc_hidden_def (__backtrace_symbols_fd)
123