1/*
2 * Copyright (c) 1987, 1993
3 *	The Regents of the University of California.  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#include "config.h"
35
36#if defined(LIBC_SCCS) && !defined(lint)
37static const char sccsid[] = "@(#)getenv.c	8.1 (Berkeley) 6/4/93";
38static const char sccsid[] = "@(#)setenv.c	8.1 (Berkeley) 6/4/93";
39#endif /* LIBC_SCCS and not lint */
40#else
41__RCSID("$NetBSD$");
42#endif
43
44#include <stdlib.h>
45#include <string.h>
46
47/*
48 * __findenv --
49 *	Returns pointer to value associated with name, if any, else NULL.
50 *	Sets offset to be the offset of the name/value combination in the
51 *	environmental array, for use by setenv(3) and unsetenv(3).
52 *	Explicitly removes '=' in argument name.
53 *
54 *	This routine *should* be a static; don't use it.
55 */
56static char *
57__findenv(register char *name, int *offset)
58{
59	extern char **environ;
60	register int len;
61	register char *np;
62	register char **p, *c;
63
64	if (name == NULL || environ == NULL)
65		return (NULL);
66	for (np = name; *np && *np != '='; ++np)
67		continue;
68	len = np - name;
69	for (p = environ; (c = *p) != NULL; ++p)
70		if (strncmp(c, name, len) == 0 && c[len] == '=') {
71			*offset = p - environ;
72			return (c + len + 1);
73		}
74	return (NULL);
75}
76
77#ifndef HAVE_SETENV
78/*
79 * setenv --
80 *	Set the value of the environmental variable "name" to be
81 *	"value".  If rewrite is set, replace any current value.
82 *
83 * PUBLIC: #ifndef HAVE_SETENV
84 * PUBLIC: int setenv __P((const char *, const char *, int));
85 * PUBLIC: #endif
86 */
87setenv(name, value, rewrite)
88	register char *name;
89	register char *value;
90	int rewrite;
91{
92	extern char **environ;
93	static int alloced;			/* if allocated space before */
94	register char *c;
95	int l_value, offset;
96
97	if (*value == '=')			/* no `=' in value */
98		++value;
99	l_value = strlen(value);
100	if ((c = __findenv(name, &offset))) {	/* find if already exists */
101		if (!rewrite)
102			return (0);
103		if (strlen(c) >= l_value) {	/* old larger; copy over */
104			while (*c++ = *value++);
105			return (0);
106		}
107	} else {					/* create new slot */
108		register int cnt;
109		register char **p;
110
111		for (p = environ, cnt = 0; *p; ++p, ++cnt);
112		if (alloced) {			/* just increase size */
113			environ = (char **)realloc((char *)environ,
114			    (size_t)(sizeof(char *) * (cnt + 2)));
115			if (!environ)
116				return (-1);
117		}
118		else {				/* get new space */
119			alloced = 1;		/* copy old entries into it */
120			p = malloc((size_t)(sizeof(char *) * (cnt + 2)));
121			if (!p)
122				return (-1);
123			memmove(p, environ, cnt * sizeof(char *));
124			environ = p;
125		}
126		environ[cnt + 1] = NULL;
127		offset = cnt;
128	}
129	for (c = (char *)name; *c && *c != '='; ++c);	/* no `=' in name */
130	if (!(environ[offset] =			/* name + `=' + value */
131	    malloc((size_t)((int)(c - name) + l_value + 2))))
132		return (-1);
133	for (c = environ[offset]; (*c = *name++) && *c != '='; ++c);
134	for (*c++ = '='; *c++ = *value++;);
135	return (0);
136}
137#endif
138
139#ifndef HAVE_UNSETENV
140/*
141 * unsetenv(name) --
142 *	Delete environmental variable "name".
143 *
144 * PUBLIC: #ifndef HAVE_UNSETENV
145 * PUBLIC: void unsetenv __P((const char *));
146 * PUBLIC: #endif
147 */
148void
149unsetenv(name)
150	char *name;
151{
152	extern char **environ;
153	register char **p;
154	int offset;
155
156	while (__findenv(name, &offset))	/* if set multiple times */
157		for (p = &environ[offset];; ++p)
158			if (!(*p = *(p + 1)))
159				break;
160}
161#endif
162