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/*
* Provide setenv() and unsetenv() on platforms that don't have them.
* From FreeBSD's libc.
*/
/*
* Copyright (c) 1987, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* $XFree86: xc/programs/xedit/lisp/env.c,v 1.1 2002/03/05 03:52:34 dawes Exp $ */
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
extern char **environ;
extern int setenv(const char *name, const char *value, int overwrite);
extern void unsetenv(const char *name);
static char *
findenv(const char *name, int *offset)
{
int len, i;
const char *np;
char **p, *cp;
if (name == NULL || environ == NULL)
return NULL;
for (np = name; *np && *np != '='; ++np)
continue;
len = np - name;
for (p = environ; (cp = *p) != NULL; ++p) {
for (np = name, i = len; i && *cp; i--)
if (*cp++ != *np++)
break;
if (i == 0 && *cp++ == '=') {
*offset = p - environ;
return cp;
}
}
return NULL;
}
/*
* setenv --
* Set the value of the environmental variable "name" to be
* "value". If overwrite is set, replace any current value.
*/
int
setenv(const char *name, const char *value, int overwrite)
{
static char **alloced; /* if allocated space before */
char *c;
int l_value, offset;
if (*value == '=') /* no '=' in value */
++value;
l_value = strlen(value);
if ((c = findenv(name, &offset))) { /* find if already exists */
if (!overwrite)
return 0;
if (strlen(c) >= l_value) { /* old larger; copy over */
while ((*c++ = *value++))
;
return 0;
}
} else { /* create new slot */
int cnt;
char **p;
for (p = environ, cnt = 0; *p; ++p, ++cnt)
;
if (alloced == environ) { /* just increase size */
p = (char **)realloc((char *)environ,
sizeof(char *) * (cnt + 2));
if (!p)
return -1;
alloced = environ = p;
} else { /* get new space */
/* copy old entries into it */
p = malloc(sizeof(char *) * (cnt + 2));
if (!p)
return -1;
memcpy(p, environ, cnt * sizeof(char *));
alloced = environ = p;
}
environ[cnt + 1] = NULL;
offset = cnt;
}
for (c = (char *)name; *c && *c != '='; ++c) /* no '=' in name */
;
if (!(environ[offset] = /* name + '=' + value */
malloc((int)(c - name) + l_value + 2)))
return -1;
for (c = environ[offset]; (*c = *name++) && *c != '='; ++c)
;
for (*c++ = '='; (*c++ = *value++); )
;
return 0;
}
/*
* unsetenv(name) --
* Delete environmental variable "name".
*/
void
unsetenv(const char *name)
{
char **p;
int offset;
while (findenv(name, &offset)) /* if set multiple times */
for (p = &environ[offset];; ++p)
if (!(*p = *(p + 1)))
break;
}
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