1: /* Environment handling for dynamic loader.
    2:    Copyright (C) 1995-1998, 2000, 2001, 2002 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 Lesser General Public
    7:    License as published by the Free Software Foundation; either
    8:    version 2.1 of the 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:    Lesser General Public License for more details.
   14: 
   15:    You should have received a copy of the GNU Lesser General Public
   16:    License along with the GNU C Library; if not, write to the Free
   17:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   18:    02111-1307 USA.  */
   19: 
   20: #include <string.h>
   21: #include <stdlib.h>
   22: #include <unistd.h>
   23: #include <ldsodefs.h>
   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:   while (*current != NULL)
   35:     {
   36:       if (__builtin_expect ((*current)[0] == 'L', 0)
   37:           && (*current)[1] == 'D' && (*current)[2] == '_')
   38:         {
   39:           result = &(*current)[3];
   40: 
   41:           /* Save current position for next visit.  */
   42:           *position = ++current;
   43: 
   44:           break;
   45:         }
   46: 
   47:       ++current;
   48:     }
   49: 
   50:   return result;
   51: }
   52: 
   53: 
   54: /* In ld.so __environ is not exported.  */
   55: extern char **__environ attribute_hidden;
   56: 
   57: int
   58: unsetenv (const char *name)
   59: {
   60:   char **ep;
   61: 
   62:   ep = __environ;
   63:   while (*ep != NULL)
   64:     {
   65:       size_t cnt = 0;
   66: 
   67:       while ((*ep)[cnt] == name[cnt] && name[cnt] != '\0')
   68:         ++cnt;
   69: 
   70:       if (name[cnt] == '\0' && (*ep)[cnt] == '=')
   71:         {
   72:           /* Found it.  Remove this pointer by moving later ones to
   73:              the front.  */
   74:           char **dp = ep;
   75: 
   76:           do
   77:             dp[0] = dp[1];
   78:           while (*dp++);
   79:           /* Continue the loop in case NAME appears again.  */
   80:         }
   81:       else
   82:         ++ep;
   83:     }
   84: 
   85:   return 0;
   86: }