Linux debugging

Check our new training course

Linux debugging, tracing, profiling & perf. analysis

Check our new training course
with Creative Commons CC-BY-SA
lecture and lab materials

Bootlin logo

Elixir Cross Referencer

/* Return list with names for address in backtrace.
   Copyright (C) 1998,1999,2000,2001,2003 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If
   not, see <http://www.gnu.org/licenses/>.

   Based on glibc/sysdeps/generic/elf/backtracesyms.c

   Copyright (C) 2010 STMicroelectronics Ltd
   Author(s): Carmelo Amoroso <carmelo.amoroso@st.com>
   * Modified to work with uClibc
     - updated headers inclusion
     - updated formatting and style
     - updated to use dladdr from libdl */

#include <execinfo.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <dlfcn.h>
#include <link.h>	/* required for __ELF_NATIVE_CLASS */

#if __ELF_NATIVE_CLASS == 32
# define WORD_WIDTH 8
#else
/* We assyme 64bits.  */
# define WORD_WIDTH 16
#endif


char ** backtrace_symbols (void *const *array,  int size)
{
	Dl_info info[size];
	int status[size];
	int cnt;
	size_t total = 0;
	char **result;

	/* Fill in the information we can get from `dladdr'.  */
	for (cnt = 0; cnt < size; ++cnt) {
		status[cnt] = dladdr (array[cnt], &info[cnt]);
		if (status[cnt] && info[cnt].dli_fname &&
			info[cnt].dli_fname[0] != '\0')
		/*
		 * We have some info, compute the length of the string which will be
		 * "<file-name>(<sym-name>) [+offset].
		 */
		total += (strlen (info[cnt].dli_fname ?: "") +
				  (info[cnt].dli_sname ?
				  strlen (info[cnt].dli_sname) + 3 + WORD_WIDTH + 3 : 1)
				  + WORD_WIDTH + 5);
		else
			total += 5 + WORD_WIDTH;
	}

	/* Allocate memory for the result.  */
	result = (char **) malloc (size * sizeof (char *) + total);
	if (result != NULL) {
		char *last = (char *) (result + size);
		for (cnt = 0; cnt < size; ++cnt) {
			result[cnt] = last;

			if (status[cnt] && info[cnt].dli_fname
				&& info[cnt].dli_fname[0] != '\0') {

				char buf[20];

				if (array[cnt] >= (void *) info[cnt].dli_saddr)
					sprintf (buf, "+%#lx",
							(unsigned long)(array[cnt] - info[cnt].dli_saddr));
				else
					sprintf (buf, "-%#lx",
					(unsigned long)(info[cnt].dli_saddr - array[cnt]));

				last += 1 + sprintf (last, "%s%s%s%s%s[%p]",
				info[cnt].dli_fname ?: "",
				info[cnt].dli_sname ? "(" : "",
				info[cnt].dli_sname ?: "",
				info[cnt].dli_sname ? buf : "",
				info[cnt].dli_sname ? ") " : " ",
				array[cnt]);
			} else
				last += 1 + sprintf (last, "[%p]", array[cnt]);
		}
		assert (last <= (char *) result + size * sizeof (char *) + total);
	}

	return result;
}