1/*
2 * Copyright (c) 1987 Regents of the University of California.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifdef HAVE_CONFIG_H
35# include "config.h"
36#endif
37#ifndef HAVE_SETENV
38
39#if defined(LIBC_SCCS) && !defined(lint)
40/*static char *sccsid = "from: @(#)setenv.c	5.6 (Berkeley) 6/4/91";*/
41static char *rcsid = "$Id: setenv.c,v 1.5 1996/09/04 22:10:42 sjg Exp $";
42#endif /* LIBC_SCCS and not lint */
43
44#include <stddef.h>
45#include <stdlib.h>
46#include <string.h>
47
48/*
49 * __findenv --
50 *	Returns pointer to value associated with name, if any, else NULL.
51 *	Sets offset to be the offset of the name/value combination in the
52 *	environmental array, for use by setenv(3) and unsetenv(3).
53 *	Explicitly removes '=' in argument name.
54 *
55 *	This routine *should* be a static; don't use it.
56 */
57static char *
58__findenv(name, offset)
59	register char *name;
60	int *offset;
61{
62	extern char **environ;
63	register int len;
64	register char **P, *C;
65
66	for (C = name, len = 0; *C && *C != '='; ++C, ++len);
67	for (P = environ; *P; ++P)
68		if (!strncmp(*P, name, len))
69			if (*(C = *P + len) == '=') {
70				*offset = P - environ;
71				return(++C);
72			}
73	return(NULL);
74}
75
76/*
77 * setenv --
78 *	Set the value of the environmental variable "name" to be
79 *	"value".  If rewrite is set, replace any current value.
80 */
81setenv(name, value, rewrite)
82	register const char *name;
83	register const char *value;
84	int rewrite;
85{
86	extern char **environ;
87	static int alloced;			/* if allocated space before */
88	register char *C;
89	int l_value, offset;
90	char *__findenv();
91
92	if (*value == '=')			/* no `=' in value */
93		++value;
94	l_value = strlen(value);
95	if ((C = __findenv(name, &offset))) {	/* find if already exists */
96		if (!rewrite)
97			return (0);
98		if (strlen(C) >= l_value) {	/* old larger; copy over */
99			while (*C++ = *value++);
100			return (0);
101		}
102	} else {					/* create new slot */
103		register int	cnt;
104		register char	**P;
105
106		for (P = environ, cnt = 0; *P; ++P, ++cnt);
107		if (alloced) {			/* just increase size */
108			environ = (char **)realloc((char *)environ,
109			    (size_t)(sizeof(char *) * (cnt + 2)));
110			if (!environ)
111				return (-1);
112		}
113		else {				/* get new space */
114			alloced = 1;		/* copy old entries into it */
115			P = (char **)malloc((size_t)(sizeof(char *) *
116			    (cnt + 2)));
117			if (!P)
118				return (-1);
119			bcopy(environ, P, cnt * sizeof(char *));
120			environ = P;
121		}
122		environ[cnt + 1] = NULL;
123		offset = cnt;
124	}
125	for (C = (char *)name; *C && *C != '='; ++C);	/* no `=' in name */
126	if (!(environ[offset] =			/* name + `=' + value */
127	    malloc((size_t)((int)(C - name) + l_value + 2))))
128		return (-1);
129	for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
130		;
131	for (*C++ = '='; *C++ = *value++; )
132		;
133	return (0);
134}
135
136/*
137 * unsetenv(name) --
138 *	Delete environmental variable "name".
139 */
140void
141unsetenv(name)
142	const char	*name;
143{
144	extern char **environ;
145	register char **P;
146	int offset;
147	char *__findenv();
148
149	while (__findenv(name, &offset))		/* if set multiple times */
150		for (P = &environ[offset];; ++P)
151			if (!(*P = *(P + 1)))
152				break;
153}
154#endif
155