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 #include "includes.h"
35 #ifndef HAVE_SETENV
36
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char *rcsid = "$OpenBSD: setenv.c,v 1.4 2001/07/09 06:57:45 deraadt Exp $";
39 #endif /* LIBC_SCCS and not lint */
40
41 #include <stdlib.h>
42 #include <string.h>
43
44 /*
45 * __findenv --
46 * Returns pointer to value associated with name, if any, else NULL.
47 * Sets offset to be the offset of the name/value combination in the
48 * environmental array, for use by setenv(3) and unsetenv(3).
49 * Explicitly removes '=' in argument name.
50 *
51 * This routine *should* be a static; don't use it.
52 */
53 char *
54 __findenv(name, offset)
55 register const char *name;
56 int *offset;
57 {
58 extern char **environ;
59 register int len, i;
60 register const char *np;
61 register char **p, *cp;
62
63 if (name == NULL || environ == NULL)
64 return (NULL);
65 for (np = name; *np && *np != '='; ++np)
66 ;
67 len = np - name;
68 for (p = environ; (cp = *p) != NULL; ++p) {
69 for (np = name, i = len; i && *cp; i--)
70 if (*cp++ != *np++)
71 break;
72 if (i == 0 && *cp++ == '=') {
73 *offset = p - environ;
74 return (cp);
75 }
76 }
77 return (NULL);
78 }
79
80 /*
81 * setenv --
82 * Set the value of the environmental variable "name" to be
83 * "value". If rewrite is set, replace any current value.
84 */
85 int
86 setenv(name, value, rewrite)
87 register const char *name;
88 register const char *value;
89 int rewrite;
90 {
91 extern char **environ;
92 static int alloced; /* if allocated space before */
93 register char *C;
94 int l_value, offset;
95 char *__findenv();
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 ;
106 return (0);
107 }
108 } else { /* create new slot */
109 register int cnt;
110 register char **P;
111
112 for (P = environ, cnt = 0; *P; ++P, ++cnt);
113 if (alloced) { /* just increase size */
114 P = (char **)realloc((void *)environ,
115 (size_t)(sizeof(char *) * (cnt + 2)));
116 if (!P)
117 return (-1);
118 environ = P;
119 }
120 else { /* get new space */
121 alloced = 1; /* copy old entries into it */
122 P = (char **)malloc((size_t)(sizeof(char *) *
123 (cnt + 2)));
124 if (!P)
125 return (-1);
126 memmove(P, environ, cnt * sizeof(char *));
127 environ = P;
128 }
129 environ[cnt + 1] = NULL;
130 offset = cnt;
131 }
132 for (C = (char *)name; *C && *C != '='; ++C); /* no `=' in name */
133 if (!(environ[offset] = /* name + `=' + value */
134 malloc((size_t)((int)(C - name) + l_value + 2))))
135 return (-1);
136 /* LINTED */
137 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
138 ;
139 for (*C++ = '='; (*C++ = *value++); )
140 ;
141 return (0);
142 }
143
144 /*
145 * unsetenv(name) --
146 * Delete environmental variable "name".
147 */
148 void
149 unsetenv(name)
150 const char *name;
151 {
152 extern char **environ;
153 register char **P;
154 int offset;
155 char *__findenv();
156
157 while (__findenv(name, &offset)) /* if set multiple times */
158 for (P = &environ[offset];; ++P)
159 /* LINTED */
160 if (!(*P = *(P + 1)))
161 break;
162 }
163
164 #endif /* HAVE_SETENV */
165
166 #pragma ident "%Z%%M% %I% %E% SMI"