1/* Write formatted list with names for addresses in backtrace to a file.
2 Copyright (C) 1998-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <execinfo.h>
20#include <string.h>
21#include <sys/uio.h>
22
23#include <_itoa.h>
24#include <ldsodefs.h>
25
26#if __ELF_NATIVE_CLASS == 32
27# define WORD_WIDTH 8
28#else
29/* We assume 64bits. */
30# define WORD_WIDTH 16
31#endif
32
33
34void
35__backtrace_symbols_fd (void *const *array, int size, int fd)
36{
37 struct iovec iov[9];
38 int cnt;
39
40 for (cnt = 0; cnt < size; ++cnt)
41 {
42 char buf[WORD_WIDTH];
43 char buf2[WORD_WIDTH];
44 Dl_info info;
45 struct link_map *map;
46 size_t last = 0;
47
48 if (_dl_addr (array[cnt], &info, &map, NULL)
49 && info.dli_fname != NULL && info.dli_fname[0] != '\0')
50 {
51 /* Name of the file. */
52 iov[0].iov_base = (void *) info.dli_fname;
53 iov[0].iov_len = strlen (info.dli_fname);
54 last = 1;
55
56 if (info.dli_sname != NULL || map->l_addr != 0)
57 {
58 size_t diff;
59
60 iov[last].iov_base = (void *) "(";
61 iov[last].iov_len = 1;
62 ++last;
63
64 if (info.dli_sname != NULL)
65 {
66 /* We have a symbol name. */
67 iov[last].iov_base = (void *) info.dli_sname;
68 iov[last].iov_len = strlen (info.dli_sname);
69 ++last;
70 }
71 else
72 /* We have no symbol, so describe it as relative to the file.
73 The load bias is more useful to the user than the load
74 address. The use of these addresses is to calculate an
75 address in the ELF file, so its prelinked bias is not
76 something we want to subtract out. */
77 info.dli_saddr = (void *) map->l_addr;
78
79 if (array[cnt] >= (void *) info.dli_saddr)
80 {
81 iov[last].iov_base = (void *) "+0x";
82 diff = array[cnt] - info.dli_saddr;
83 }
84 else
85 {
86 iov[last].iov_base = (void *) "-0x";
87 diff = info.dli_saddr - array[cnt];
88 }
89 iov[last].iov_len = 3;
90 ++last;
91
92 iov[last].iov_base = _itoa_word ((unsigned long int) diff,
93 &buf2[WORD_WIDTH], 16, 0);
94 iov[last].iov_len = (&buf2[WORD_WIDTH]
95 - (char *) iov[last].iov_base);
96 ++last;
97
98 iov[last].iov_base = (void *) ")";
99 iov[last].iov_len = 1;
100 ++last;
101 }
102 }
103
104 iov[last].iov_base = (void *) "[0x";
105 iov[last].iov_len = 3;
106 ++last;
107
108 iov[last].iov_base = _itoa_word ((unsigned long int) array[cnt],
109 &buf[WORD_WIDTH], 16, 0);
110 iov[last].iov_len = &buf[WORD_WIDTH] - (char *) iov[last].iov_base;
111 ++last;
112
113 iov[last].iov_base = (void *) "]\n";
114 iov[last].iov_len = 2;
115 ++last;
116
117 __writev (fd, iov, last);
118 }
119}
120weak_alias (__backtrace_symbols_fd, backtrace_symbols_fd)
121libc_hidden_def (__backtrace_symbols_fd)
122