libiberty/setenv.c

   1 /* Copyright (C) 1992, 1995, 1996, 1997 Free Software Foundation, Inc.
   2    This file based on setenv.c in the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #if HAVE_CONFIG_H
  20 # include <config.h>
  21 #endif
  22
  23 #include "ansidecl.h"
  24
  25 #include <errno.h>
  26 #if !defined(errno) && !defined(HAVE_ERRNO_DECL)
  27 extern int errno;
  28 #endif
  29 #define __set_errno(ev) ((errno) = (ev))
  30
  31 #if HAVE_STDLIB_H
  32 # include <stdlib.h>
  33 #endif
  34 #if HAVE_STRING_H
  35 # include <string.h>
  36 #endif
  37 #if HAVE_UNISTD_H
  38 # include <unistd.h>
  39 #endif
  40
  41 #define __environ       environ
  42 #ifndef HAVE_ENVIRON_DECL
  43 extern char **environ;
  44 #endif
  45
  46 /* LOCK and UNLOCK are defined as no-ops.  This makes the libiberty
  47  * implementation MT-Unsafe. */
  48 #define LOCK
  49 #define UNLOCK
  50
  51 /* Below this point, it's verbatim code from the glibc-2.0 implementation */
  52
  53 /* If this variable is not a null pointer we allocated the current
  54    environment.  */
  55 static char **last_environ;
  56
  57
  58 int
  59 setenv (name, value, replace)
  60      const char *name;
  61      const char *value;
  62      int replace;
  63 {
  64   register char **ep;
  65   register size_t size;
  66   const size_t namelen = strlen (name);
  67   const size_t vallen = strlen (value) + 1;
  68
  69   LOCK;
  70
  71   size = 0;
  72   if (__environ != NULL)
  73     for (ep = __environ; *ep != NULL; ++ep)
  74       if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
  75         break;
  76       else
  77         ++size;
  78
  79   if (__environ == NULL || *ep == NULL)
  80     {
  81       char **new_environ;
  82       if (__environ == last_environ && __environ != NULL)
  83         /* We allocated this space; we can extend it.  */
  84         new_environ = (char **) realloc (last_environ,
  85                                          (size + 2) * sizeof (char *));
  86       else
  87         new_environ = (char **) malloc ((size + 2) * sizeof (char *));
  88
  89       if (new_environ == NULL)
  90         {
  91           UNLOCK;
  92           return -1;
  93         }
  94
  95       new_environ[size] = malloc (namelen + 1 + vallen);
  96       if (new_environ[size] == NULL)
  97         {
  98           free ((char *) new_environ);
  99           __set_errno (ENOMEM);
 100           UNLOCK;
 101           return -1;
 102         }
 103
 104       if (__environ != last_environ)
 105         memcpy ((char *) new_environ, (char *) __environ,
 106                 size * sizeof (char *));
 107
 108       memcpy (new_environ[size], name, namelen);
 109       new_environ[size][namelen] = '=';
 110       memcpy (&new_environ[size][namelen + 1], value, vallen);
 111
 112       new_environ[size + 1] = NULL;
 113
 114       last_environ = __environ = new_environ;
 115     }
 116   else if (replace)
 117     {
 118       size_t len = strlen (*ep);
 119       if (len + 1 < namelen + 1 + vallen)
 120         {
 121           /* The existing string is too short; malloc a new one.  */
 122           char *new = malloc (namelen + 1 + vallen);
 123           if (new == NULL)
 124             {
 125               UNLOCK;
 126               return -1;
 127             }
 128           *ep = new;
 129         }
 130       memcpy (*ep, name, namelen);
 131       (*ep)[namelen] = '=';
 132       memcpy (&(*ep)[namelen + 1], value, vallen);
 133     }
 134
 135   UNLOCK;
 136
 137   return 0;
 138 }
 139
 140 void
 141 unsetenv (name)
 142      const char *name;
 143 {
 144   const size_t len = strlen (name);
 145   char **ep;
 146
 147   LOCK;
 148
 149   for (ep = __environ; *ep; ++ep)
 150     if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
 151       {
 152         /* Found it.  Remove this pointer by moving later ones back.  */
 153         char **dp = ep;
 154         do
 155           dp[0] = dp[1];
 156         while (*dp++);
 157         /* Continue the loop in case NAME appears again.  */
 158       }
 159
 160   UNLOCK;
 161 }