1/*	$OpenBSD: setenv.c,v 1.9 2005/08/08 08:05:37 espie Exp $ */
2/*
3 * Copyright (c) 1987 Regents of the University of California.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31/* OPENBSD ORIGINAL: lib/libc/stdlib/setenv.c */
32
33#include "includes.h"
34#if !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV)
35
36#include <stdlib.h>
37#include <string.h>
38
39extern char **environ;
40
41/* OpenSSH Portable: __findenv is from getenv.c rev 1.8, made static */
42/*
43 * __findenv --
44 *	Returns pointer to value associated with name, if any, else NULL.
45 *	Sets offset to be the offset of the name/value combination in the
46 *	environmental array, for use by setenv(3) and unsetenv(3).
47 *	Explicitly removes '=' in argument name.
48 */
49static char *
50__findenv(const char *name, size_t *offset)
51{
52	extern char **environ;
53	int len, i;
54	const char *np;
55	char **p, *cp;
56
57	if (name == NULL || environ == NULL)
58		return (NULL);
59	for (np = name; *np && *np != '='; ++np)
60		;
61	len = np - name;
62	for (p = environ; (cp = *p) != NULL; ++p) {
63		for (np = name, i = len; i && *cp; i--)
64			if (*cp++ != *np++)
65				break;
66		if (i == 0 && *cp++ == '=') {
67			*offset = p - environ;
68			return (cp);
69		}
70	}
71	return (NULL);
72}
73
74#ifndef HAVE_SETENV
75/*
76 * setenv --
77 *	Set the value of the environmental variable "name" to be
78 *	"value".  If rewrite is set, replace any current value.
79 */
80int
81setenv(const char *name, const char *value, int rewrite)
82{
83	static char **lastenv;			/* last value of environ */
84	char *C;
85	size_t l_value, offset;
86
87	if (*value == '=')			/* no `=' in value */
88		++value;
89	l_value = strlen(value);
90	if ((C = __findenv(name, &offset))) {	/* find if already exists */
91		if (!rewrite)
92			return (0);
93		if (strlen(C) >= l_value) {	/* old larger; copy over */
94			while ((*C++ = *value++))
95				;
96			return (0);
97		}
98	} else {					/* create new slot */
99		size_t cnt;
100		char **P;
101
102		for (P = environ; *P != NULL; P++)
103			;
104		cnt = P - environ;
105		P = (char **)realloc(lastenv, sizeof(char *) * (cnt + 2));
106		if (!P)
107			return (-1);
108		if (lastenv != environ)
109			memcpy(P, environ, cnt * sizeof(char *));
110		lastenv = environ = P;
111		offset = cnt;
112		environ[cnt + 1] = NULL;
113	}
114	for (C = (char *)name; *C && *C != '='; ++C)
115		;				/* no `=' in name */
116	if (!(environ[offset] =			/* name + `=' + value */
117	    malloc((size_t)((int)(C - name) + l_value + 2))))
118		return (-1);
119	for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
120		;
121	for (*C++ = '='; (*C++ = *value++); )
122		;
123	return (0);
124}
125#endif /* HAVE_SETENV */
126
127#ifndef HAVE_UNSETENV
128/*
129 * unsetenv(name) --
130 *	Delete environmental variable "name".
131 */
132void
133unsetenv(const char *name)
134{
135	char **P;
136	size_t offset;
137
138	while (__findenv(name, &offset))	/* if set multiple times */
139		for (P = &environ[offset];; ++P)
140			if (!(*P = *(P + 1)))
141				break;
142}
143#endif /* HAVE_UNSETENV */
144
145#endif /* !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV) */
146