sysdeps/generic/dl-environ.c

   1 /*Environment handling for dynamic loader.
   2    Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <string.h>
  21
  22
  23 extern char **_environ;
  24
  25 /* Walk through the environment of the process and return all entries
  26    starting with `LD_'.  */
  27 char *
  28 internal_function
  29 _dl_next_ld_env_entry (char ***position)
  30 {
  31   char **current = *position;
  32   char *result = NULL;
  33
  34   if (current == NULL)
  35     /* We start over.  */
  36     current = _environ;
  37
  38   while (result == NULL && *current != NULL)
  39     {
  40       if ((*current)[0] == 'L' && (*current)[1] == 'D' && (*current)[2] == '_')
  41         result = *current;
  42
  43       ++current;
  44     }
  45
  46   /* Save current position for next visit.  */
  47   *position = current;
  48
  49   return result;
  50 }
  51
  52 void
  53 unsetenv (const char *name)
  54 {
  55   const size_t len = strlen (name);
  56   char **ep;
  57
  58   for (ep = _environ; *ep != NULL; ++ep)
  59     if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
  60       {
  61         /* Found it.  Remove this pointer by moving later ones back.  */
  62         char **dp = ep;
  63
  64         do
  65           dp[0] = dp[1];
  66         while (*dp++);
  67         /* Continue the loop in case NAME appears again.  */
  68       }
  69 }