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1 /*	$OpenBSD: setenv.c,v 1.13 2010/08/23 22:31:50 millert 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 
35 #if !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV)
36 
37 #include <errno.h>
38 #include <stdlib.h>
39 #include <string.h>
40 
41 extern char **environ;
42 static char **lastenv;				/* last value of environ */
43 
44 /* OpenSSH Portable: __findenv is from getenv.c rev 1.8, made static */
45 /*
46  * __findenv --
47  *	Returns pointer to value associated with name, if any, else NULL.
48  *	Starts searching within the environmental array at offset.
49  *	Sets offset to be the offset of the name/value combination in the
50  *	environmental array, for use by putenv(3), setenv(3) and unsetenv(3).
51  *	Explicitly removes '=' in argument name.
52  *
53  *	This routine *should* be a static; don't use it.
54  */
55 static char *
__findenv(const char * name,int len,int * offset)56 __findenv(const char *name, int len, int *offset)
57 {
58 	extern char **environ;
59 	int i;
60 	const char *np;
61 	char **p, *cp;
62 
63 	if (name == NULL || environ == NULL)
64 		return (NULL);
65 	for (p = environ + *offset; (cp = *p) != NULL; ++p) {
66 		for (np = name, i = len; i && *cp; i--)
67 			if (*cp++ != *np++)
68 				break;
69 		if (i == 0 && *cp++ == '=') {
70 			*offset = p - environ;
71 			return (cp);
72 		}
73 	}
74 	return (NULL);
75 }
76 
77 #if 0 /* nothing uses putenv */
78 /*
79  * putenv --
80  *	Add a name=value string directly to the environmental, replacing
81  *	any current value.
82  */
83 int
84 putenv(char *str)
85 {
86 	char **P, *cp;
87 	size_t cnt;
88 	int offset = 0;
89 
90 	for (cp = str; *cp && *cp != '='; ++cp)
91 		;
92 	if (*cp != '=') {
93 		errno = EINVAL;
94 		return (-1);			/* missing `=' in string */
95 	}
96 
97 	if (__findenv(str, (int)(cp - str), &offset) != NULL) {
98 		environ[offset++] = str;
99 		/* could be set multiple times */
100 		while (__findenv(str, (int)(cp - str), &offset)) {
101 			for (P = &environ[offset];; ++P)
102 				if (!(*P = *(P + 1)))
103 					break;
104 		}
105 		return (0);
106 	}
107 
108 	/* create new slot for string */
109 	for (P = environ; *P != NULL; P++)
110 		;
111 	cnt = P - environ;
112 	P = (char **)realloc(lastenv, sizeof(char *) * (cnt + 2));
113 	if (!P)
114 		return (-1);
115 	if (lastenv != environ)
116 		memcpy(P, environ, cnt * sizeof(char *));
117 	lastenv = environ = P;
118 	environ[cnt] = str;
119 	environ[cnt + 1] = NULL;
120 	return (0);
121 }
122 
123 #endif
124 
125 #ifndef HAVE_SETENV
126 /*
127  * setenv --
128  *	Set the value of the environmental variable "name" to be
129  *	"value".  If rewrite is set, replace any current value.
130  */
131 int
setenv(const char * name,const char * value,int rewrite)132 setenv(const char *name, const char *value, int rewrite)
133 {
134 	char *C, **P;
135 	const char *np;
136 	int l_value, offset = 0;
137 
138 	for (np = name; *np && *np != '='; ++np)
139 		;
140 #ifdef notyet
141 	if (*np) {
142 		errno = EINVAL;
143 		return (-1);			/* has `=' in name */
144 	}
145 #endif
146 
147 	l_value = strlen(value);
148 	if ((C = __findenv(name, (int)(np - name), &offset)) != NULL) {
149 		int tmpoff = offset + 1;
150 		if (!rewrite)
151 			return (0);
152 #if 0 /* XXX - existing entry may not be writable */
153 		if (strlen(C) >= l_value) {	/* old larger; copy over */
154 			while ((*C++ = *value++))
155 				;
156 			return (0);
157 		}
158 #endif
159 		/* could be set multiple times */
160 		while (__findenv(name, (int)(np - name), &tmpoff)) {
161 			for (P = &environ[tmpoff];; ++P)
162 				if (!(*P = *(P + 1)))
163 					break;
164 		}
165 	} else {					/* create new slot */
166 		size_t cnt;
167 
168 		for (P = environ; *P != NULL; P++)
169 			;
170 		cnt = P - environ;
171 		P = (char **)realloc(lastenv, sizeof(char *) * (cnt + 2));
172 		if (!P)
173 			return (-1);
174 		if (lastenv != environ)
175 			memcpy(P, environ, cnt * sizeof(char *));
176 		lastenv = environ = P;
177 		offset = cnt;
178 		environ[cnt + 1] = NULL;
179 	}
180 	if (!(environ[offset] =			/* name + `=' + value */
181 	    malloc((size_t)((int)(np - name) + l_value + 2))))
182 		return (-1);
183 	for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
184 		;
185 	for (*C++ = '='; (*C++ = *value++); )
186 		;
187 	return (0);
188 }
189 
190 #endif /* HAVE_SETENV */
191 
192 #ifndef HAVE_UNSETENV
193 /*
194  * unsetenv(name) --
195  *	Delete environmental variable "name".
196  */
197 int
unsetenv(const char * name)198 unsetenv(const char *name)
199 {
200 	char **P;
201 	const char *np;
202 	int offset = 0;
203 
204 	if (!name || !*name) {
205 		errno = EINVAL;
206 		return (-1);
207 	}
208 	for (np = name; *np && *np != '='; ++np)
209 		;
210 	if (*np) {
211 		errno = EINVAL;
212 		return (-1);			/* has `=' in name */
213 	}
214 
215 	/* could be set multiple times */
216 	while (__findenv(name, (int)(np - name), &offset)) {
217 		for (P = &environ[offset];; ++P)
218 			if (!(*P = *(P + 1)))
219 				break;
220 	}
221 	return (0);
222 }
223 #endif /* HAVE_UNSETENV */
224 
225 #endif /* !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV) */
226 
227