glibc/sysdeps/generic/putenv.c
1995-02-18 01:27:10 +00:00

102 lines
2.6 KiB
C

/* Copyright (C) 1991, 1994 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <errno.h>
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#if defined (__GNU_LIBRARY__) || defined (HAVE_STDLIB_H)
#include <stdlib.h>
#endif
#if defined (__GNU_LIBRARY__) || defined (HAVE_STRING_H)
#include <string.h>
#endif
#if defined (__GNU_LIBRARY__) || defined (HAVE_UNISTD_H)
#include <unistd.h>
#endif
#if !defined (__GNU_LIBRARY__) && !defined (HAVE_STRCHR)
#define strchr index
#endif
#if !defined (__GNU_LIBRARY__) && !defined (HAVE_MEMCPY)
#define memcpy(d,s,n) bcopy ((s), (d), (n))
#endif
#ifndef HAVE_GNU_LD
#define __environ environ
#endif
/* Put STRING, which is of the form "NAME=VALUE", in the environment. */
int
putenv (string)
const char *string;
{
const char *const name_end = strchr (string, '=');
register size_t size;
register char **ep;
if (name_end == NULL)
{
/* Remove the variable from the environment. */
size = strlen (string);
for (ep = __environ; *ep != NULL; ++ep)
if (!strncmp (*ep, string, size) && (*ep)[size] == '=')
{
while (ep[1] != NULL)
{
ep[0] = ep[1];
++ep;
}
*ep = NULL;
return 0;
}
}
size = 0;
for (ep = __environ; *ep != NULL; ++ep)
if (!strncmp (*ep, string, name_end - string) &&
(*ep)[name_end - string] == '=')
break;
else
++size;
if (*ep == NULL)
{
static char **last_environ = NULL;
char **new_environ = (char **) malloc ((size + 2) * sizeof (char *));
if (new_environ == NULL)
return -1;
(void) memcpy ((void *) new_environ, (void *) __environ,
size * sizeof (char *));
new_environ[size] = (char *) string;
new_environ[size + 1] = NULL;
if (last_environ != NULL)
free ((void *) last_environ);
last_environ = new_environ;
__environ = new_environ;
}
else
*ep = (char *) string;
return 0;
}