elf/dl-origin.c

   1 /* Find path of executable.
   2    Copyright (C) 1998-2017 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; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <sys/param.h>
  23 #include <ldsodefs.h>
  24
  25 #include <dl-dst.h>
  26
  27
  28 const char *
  29 _dl_get_origin (void)
  30 {
  31   char *result = (char *) -1;
  32   /* We use the environment variable LD_ORIGIN_PATH.  If it is set make
  33      a copy and strip out trailing slashes.  */
  34   if (GLRO(dl_origin_path) != NULL)
  35     {
  36       size_t len = strlen (GLRO(dl_origin_path));
  37       result = (char *) malloc (len + 1);
  38       if (result == NULL)
  39         result = (char *) -1;
  40       else
  41         {
  42           char *cp = __mempcpy (result, GLRO(dl_origin_path), len);
  43           while (cp > result + 1 && cp[-1] == '/')
  44             --cp;
  45           *cp = '\0';
  46         }
  47     }
  48
  49   return result;
  50 }