libubacktrace/backtracesyms.c

   1 /* Return list with names for address in backtrace.
   2    Copyright (C) 1998,1999,2000,2001,2003 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; see the file COPYING.LIB.  If
  18    not, see <http://www.gnu.org/licenses/>.
  19
  20    Based on glibc/sysdeps/generic/elf/backtracesyms.c
  21
  22    Copyright (C) 2010 STMicroelectronics Ltd
  23    Author(s): Carmelo Amoroso <carmelo.amoroso@st.com>
  24    * Modified to work with uClibc
  25      - updated headers inclusion
  26      - updated formatting and style
  27      - updated to use dladdr from libdl */
  28
  29 #include <execinfo.h>
  30 #include <assert.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include <dlfcn.h>
  36 #include <link.h>       /* required for __ELF_NATIVE_CLASS */
  37
  38 #if __ELF_NATIVE_CLASS == 32
  39 # define WORD_WIDTH 8
  40 #else
  41 /* We assyme 64bits.  */
  42 # define WORD_WIDTH 16
  43 #endif
  44
  45
  46 char ** backtrace_symbols (void *const *array,  int size)
  47 {
  48         Dl_info info[size];
  49         int status[size];
  50         int cnt;
  51         size_t total = 0;
  52         char **result;
  53
  54         /* Fill in the information we can get from `dladdr'.  */
  55         for (cnt = 0; cnt < size; ++cnt) {
  56                 status[cnt] = dladdr (array[cnt], &info[cnt]);
  57                 if (status[cnt] && info[cnt].dli_fname &&
  58                         info[cnt].dli_fname[0] != '\0')
  59                 /*
  60                  * We have some info, compute the length of the string which will be
  61                  * "<file-name>(<sym-name>) [+offset].
  62                  */
  63                 total += (strlen (info[cnt].dli_fname ?: "") +
  64                                   (info[cnt].dli_sname ?
  65                                   strlen (info[cnt].dli_sname) + 3 + WORD_WIDTH + 3 : 1)
  66                                   + WORD_WIDTH + 5);
  67                 else
  68                         total += 5 + WORD_WIDTH;
  69         }
  70
  71         /* Allocate memory for the result.  */
  72         result = (char **) malloc (size * sizeof (char *) + total);
  73         if (result != NULL) {
  74                 char *last = (char *) (result + size);
  75                 for (cnt = 0; cnt < size; ++cnt) {
  76                         result[cnt] = last;
  77
  78                         if (status[cnt] && info[cnt].dli_fname
  79                                 && info[cnt].dli_fname[0] != '\0') {
  80
  81                                 char buf[20];
  82
  83                                 if (array[cnt] >= (void *) info[cnt].dli_saddr)
  84                                         sprintf (buf, "+%#lx",
  85                                                         (unsigned long)(array[cnt] - info[cnt].dli_saddr));
  86                                 else
  87                                         sprintf (buf, "-%#lx",
  88                                         (unsigned long)(info[cnt].dli_saddr - array[cnt]));
  89
  90                                 last += 1 + sprintf (last, "%s%s%s%s%s[%p]",
  91                                 info[cnt].dli_fname ?: "",
  92                                 info[cnt].dli_sname ? "(" : "",
  93                                 info[cnt].dli_sname ?: "",
  94                                 info[cnt].dli_sname ? buf : "",
  95                                 info[cnt].dli_sname ? ") " : " ",
  96                                 array[cnt]);
  97                         } else
  98                                 last += 1 + sprintf (last, "[%p]", array[cnt]);
  99                 }
 100                 assert (last <= (char *) result + size * sizeof (char *) + total);
 101         }
 102
 103         return result;
 104 }