libubacktrace/backtracesymsfd.c

   1 /* Write formatted list with names for addresses in backtrace to a file.
   2    Copyright (C) 1998, 2000, 2003, 2005 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/backtracesymsfd.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      - updated to use snprintf instead of _itoa_word */
  29
  30 #include <execinfo.h>
  31 #include <string.h>
  32 #include <sys/uio.h>
  33 #include <dlfcn.h>
  34 #include <stdio.h>
  35 #include <link.h>       /* required for __ELF_NATIVE_CLASS */
  36
  37 #if __ELF_NATIVE_CLASS == 32
  38 # define WORD_WIDTH 8
  39 #else
  40 /* We assyme 64bits.  */
  41 # define WORD_WIDTH 16
  42 #endif
  43
  44 #define BUF_SIZE (WORD_WIDTH + 1)
  45
  46 void backtrace_symbols_fd (void *const *array, int size, int fd)
  47 {
  48         struct iovec iov[9];
  49         int cnt;
  50
  51         for (cnt = 0; cnt < size; ++cnt) {
  52                 char buf[BUF_SIZE];
  53                 Dl_info info;
  54                 size_t last = 0;
  55                 size_t len = 0;
  56
  57                 memset(buf, 0, sizeof(buf));
  58                 if (dladdr (array[cnt], &info)
  59                         && info.dli_fname && info.dli_fname[0] != '\0') {
  60                         /* Name of the file.  */
  61                         iov[0].iov_base = (void *) info.dli_fname;
  62                         iov[0].iov_len = strlen (info.dli_fname);
  63                         last = 1;
  64
  65                         /* Symbol name.  */
  66                         if (info.dli_sname != NULL) {
  67                                 char buf2[BUF_SIZE];
  68                                 memset(buf2, 0, sizeof(buf2));
  69                                 size_t diff;
  70
  71                                 iov[1].iov_base = (void *) "(";
  72                                 iov[1].iov_len = 1;
  73                                 iov[2].iov_base = (void *) info.dli_sname;
  74                                 iov[2].iov_len = strlen (info.dli_sname);
  75
  76                                 if (array[cnt] >= (void *) info.dli_saddr) {
  77                                         iov[3].iov_base = (void *) "+0x";
  78                                         diff = array[cnt] - info.dli_saddr;
  79                                 } else {
  80                                         iov[3].iov_base = (void *) "-0x";
  81                                         diff = info.dli_saddr - array[cnt];
  82                                 }
  83
  84                                 iov[3].iov_len = 3;
  85
  86                                 /* convert diff to a string in hex format */
  87                                 len = snprintf(buf2, sizeof(buf2), "%lx", (unsigned long) diff);
  88                                 iov[4].iov_base = buf2;
  89                                 iov[4].iov_len = len;
  90
  91                                 iov[5].iov_base = (void *) ")";
  92                                 iov[5].iov_len = 1;
  93
  94                                 last = 6;
  95                         }
  96                 }
  97
  98                 iov[last].iov_base = (void *) "[0x";
  99                 iov[last].iov_len = 3;
 100                 ++last;
 101
 102                 /* convert array[cnt] to a string in hex format */
 103                 len = snprintf(buf, sizeof(buf), "%lx", (unsigned long) array[cnt]);
 104                 iov[last].iov_base = buf;
 105                 iov[last].iov_len = len;
 106
 107                 ++last;
 108
 109                 iov[last].iov_base = (void *) "]\n";
 110                 iov[last].iov_len = 2;
 111                 ++last;
 112
 113                 writev (fd, iov, last);
 114         }
 115 }