1/*	$OpenBSD: setenv.c,v 1.16 2015/09/13 08:31:47 guenther 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#include <errno.h>
32#include <stdlib.h>
33#include <string.h>
34
35extern char **environ;
36static char **lastenv;				/* last value of environ */
37
38/*
39 * putenv --
40 *	Add a name=value string directly to the environmental, replacing
41 *	any current value.
42 */
43int
44putenv(char *str)
45{
46	char **P, *cp;
47	size_t cnt;
48	int offset = 0;
49
50	for (cp = str; *cp && *cp != '='; ++cp)
51		;
52	if (*cp != '=') {
53		errno = EINVAL;
54		return (-1);			/* missing `=' in string */
55	}
56
57	if (__findenv(str, (int)(cp - str), &offset) != NULL) {
58		environ[offset++] = str;
59		/* could be set multiple times */
60		while (__findenv(str, (int)(cp - str), &offset)) {
61			for (P = &environ[offset];; ++P)
62				if (!(*P = *(P + 1)))
63					break;
64		}
65		return (0);
66	}
67
68	/* create new slot for string */
69	for (P = environ; *P != NULL; P++)
70		;
71	cnt = P - environ;
72	P = reallocarray(lastenv, cnt + 2, sizeof(char *));
73	if (!P)
74		return (-1);
75	if (lastenv != environ)
76		memcpy(P, environ, cnt * sizeof(char *));
77	lastenv = environ = P;
78	environ[cnt] = str;
79	environ[cnt + 1] = NULL;
80	return (0);
81}
82DEF_WEAK(putenv);
83
84/*
85 * setenv --
86 *	Set the value of the environmental variable "name" to be
87 *	"value".  If rewrite is set, replace any current value.
88 */
89int
90setenv(const char *name, const char *value, int rewrite)
91{
92	char *C, **P;
93	const char *np;
94	int l_value, offset = 0;
95
96	if (!name || !*name) {
97		errno = EINVAL;
98		return (-1);
99	}
100	for (np = name; *np && *np != '='; ++np)
101		;
102	if (*np) {
103		errno = EINVAL;
104		return (-1);			/* has `=' in name */
105	}
106
107	l_value = strlen(value);
108	if ((C = __findenv(name, (int)(np - name), &offset)) != NULL) {
109		int tmpoff = offset + 1;
110		if (!rewrite)
111			return (0);
112#if 0 /* XXX - existing entry may not be writable */
113		if (strlen(C) >= l_value) {	/* old larger; copy over */
114			while ((*C++ = *value++))
115				;
116			return (0);
117		}
118#endif
119		/* could be set multiple times */
120		while (__findenv(name, (int)(np - name), &tmpoff)) {
121			for (P = &environ[tmpoff];; ++P)
122				if (!(*P = *(P + 1)))
123					break;
124		}
125	} else {					/* create new slot */
126		size_t cnt;
127
128		for (P = environ; *P != NULL; P++)
129			;
130		cnt = P - environ;
131		P = reallocarray(lastenv, cnt + 2, sizeof(char *));
132		if (!P)
133			return (-1);
134		if (lastenv != environ)
135			memcpy(P, environ, cnt * sizeof(char *));
136		lastenv = environ = P;
137		offset = cnt;
138		environ[cnt + 1] = NULL;
139	}
140	if (!(environ[offset] =			/* name + `=' + value */
141	    malloc((size_t)((int)(np - name) + l_value + 2))))
142		return (-1);
143	for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
144		;
145	for (*C++ = '='; (*C++ = *value++); )
146		;
147	return (0);
148}
149DEF_WEAK(setenv);
150
151/*
152 * unsetenv(name) --
153 *	Delete environmental variable "name".
154 */
155int
156unsetenv(const char *name)
157{
158	char **P;
159	const char *np;
160	int offset = 0;
161
162	if (!name || !*name) {
163		errno = EINVAL;
164		return (-1);
165	}
166	for (np = name; *np && *np != '='; ++np)
167		;
168	if (*np) {
169		errno = EINVAL;
170		return (-1);			/* has `=' in name */
171	}
172
173	/* could be set multiple times */
174	while (__findenv(name, (int)(np - name), &offset)) {
175		for (P = &environ[offset];; ++P)
176			if (!(*P = *(P + 1)))
177				break;
178	}
179	return (0);
180}
181DEF_WEAK(unsetenv);
182