1 /* $NetBSD: backtrace.c,v 1.3 2013/08/29 14:58:56 christos Exp $ */
4 * Copyright (c) 2012 The NetBSD Foundation, Inc.
7 * This code is derived from software contributed to The NetBSD Foundation
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
31 #include <sys/cdefs.h>
32 __RCSID("$NetBSD: backtrace.c,v 1.3 2013/08/29 14:58:56 christos Exp $");
34 #include <sys/param.h>
52 #define SELF "/proc/self/exe"
54 #include <sys/sysctl.h>
55 #define SELF "/proc/curproc/file"
61 const char *pathname = SELF;
62 #ifdef KERN_PROC_PATHNAME
63 static const int name[] = {
64 CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1,
66 char path[MAXPATHLEN];
70 if (sysctl(name, 4, path, &len, NULL, 0) != -1)
73 return open(pathname, flags);
77 static int __printflike(4, 5)
78 rasprintf(char **buf, size_t *bufsiz, size_t offs, const char *fmt, ...)
84 if (*buf && offs < *bufsiz) {
89 len = vsnprintf(*buf + offs, *bufsiz - offs, fmt, ap);
92 if (len < 0 || (size_t)len + 1 < *bufsiz - offs)
94 nbufsiz = MAX(*bufsiz + 512, (size_t)len + 1);
96 nbufsiz = MAX(offs, *bufsiz) + 512;
98 nbuf = realloc(*buf, nbufsiz);
110 * %d = symbol_address - address
111 * %D = if symbol_address == address "" else +%d
115 format_string(char **buf, size_t *bufsiz, size_t offs, const char *fmt,
116 Dl_info *dli, const void *addr)
118 ptrdiff_t diff = (const char *)addr - (const char *)dli->dli_saddr;
122 for (; *fmt; fmt++) {
127 len = rasprintf(buf, bufsiz, o, "%p", addr);
130 len = rasprintf(buf, bufsiz, o, "%s", dli->dli_sname);
134 len = rasprintf(buf, bufsiz, o, "+0x%tx", diff);
139 len = rasprintf(buf, bufsiz, o, "0x%tx", diff);
142 len = rasprintf(buf, bufsiz, o, "%s", dli->dli_fname);
146 len = rasprintf(buf, bufsiz, o, "%c", *fmt);
157 format_address(symtab_t *st, char **buf, size_t *bufsiz, size_t offs,
158 const char *fmt, const void *addr)
162 memset(&dli, 0, sizeof(dli));
163 (void)dladdr(addr, &dli);
165 symtab_find(st, addr, &dli);
167 if (dli.dli_sname == NULL)
168 dli.dli_sname = "???";
169 if (dli.dli_fname == NULL)
170 dli.dli_fname = "???";
171 if (dli.dli_saddr == NULL)
172 dli.dli_saddr = (void *)(intptr_t)addr;
174 return format_string(buf, bufsiz, offs, fmt, &dli, addr);
178 backtrace_symbols_fmt(void *const *trace, size_t len, const char *fmt)
181 static const size_t slen = sizeof(char *) + 64; /* estimate */
186 if ((fd = open_self(O_RDONLY)) != -1)
187 st = symtab_create(fd, -1, STT_FUNC);
191 if ((ptr = calloc(len, slen)) == NULL)
194 size_t psize = len * slen;
195 size_t offs = len * sizeof(char *);
197 /* We store only offsets in the first pass because of realloc */
198 for (size_t i = 0; i < len; i++) {
200 ((char **)(void *)ptr)[i] = (void *)offs;
201 x = format_address(st, &ptr, &psize, offs, fmt, trace[i]);
209 assert(offs < psize);
212 /* Change offsets to pointers */
213 for (size_t j = 0; j < len; j++)
214 ((char **)(void *)ptr)[j] += (intptr_t)ptr;
225 backtrace_symbols_fd_fmt(void *const *trace, size_t len, int fd,
228 char **s = backtrace_symbols_fmt(trace, len, fmt);
231 for (size_t i = 0; i < len; i++)
232 if (dprintf(fd, "%s\n", s[i]) < 0)
238 static const char fmt[] = "%a <%n%D> at %f";
241 backtrace_symbols(void *const *trace, size_t len)
243 return backtrace_symbols_fmt(trace, len, fmt);
247 backtrace_symbols_fd(void *const *trace, size_t len, int fd)
249 return backtrace_symbols_fd_fmt(trace, len, fd, fmt);