1 /** $MirOS: src/lib/libc/stdlib/setenv.c,v 1.6 2006/07/04 21:43:02 tg Exp $ */
2 /* $OpenBSD: setenv.c,v 1.9 2005/08/08 08:05:37 espie Exp $ */
3 /*
4 * Copyright (c) 1987 Regents of the University of California.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <errno.h>
33 #include <stdlib.h>
34 #include <string.h>
35
36 __RCSID("$MirOS: src/lib/libc/stdlib/setenv.c,v 1.6 2006/07/04 21:43:02 tg Exp $");
37
38 char *__findenv(const char *name, int *offset);
39
40 extern char **environ;
41
42 /*
43 * setenv --
44 * Set the value of the environmental variable "name" to be
45 * "value". If rewrite is set, replace any current value.
46 */
47 int
setenv(const char * name,const char * value,int rewrite)48 setenv(const char *name, const char *value, int rewrite)
49 {
50 static char **lastenv; /* last value of environ */
51 char *C;
52 const char *CC;
53 int l_value, offset;
54
55 if (*value == '=') /* no `=' in value */
56 ++value;
57 l_value = strlen(value);
58 if ((C = __findenv(name, &offset))) { /* find if already exists */
59 if (!rewrite)
60 return (0);
61 if (strlen(C) >= (size_t)l_value) { /* old larger; copy over */
62 while ((*C++ = *value++))
63 ;
64 return (0);
65 }
66 } else { /* create new slot */
67 size_t cnt;
68 char **P;
69
70 for (P = environ; *P != NULL; P++)
71 ;
72 cnt = P - environ;
73 P = (char **)realloc(lastenv, sizeof(char *) * (cnt + 2));
74 if (!P)
75 return (-1);
76 if (lastenv != environ)
77 memcpy(P, environ, cnt * sizeof(char *));
78 lastenv = environ = P;
79 offset = cnt;
80 environ[cnt + 1] = NULL;
81 }
82 for (CC = name; *CC && *CC != '='; ++CC)
83 ; /* no `=' in name */
84 if (!(environ[offset] = /* name + `=' + value */
85 malloc((size_t)((int)(CC - name) + l_value + 2))))
86 return (-1);
87 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
88 ;
89 for (*C++ = '='; (*C++ = *value++); )
90 ;
91 return (0);
92 }
93
94 /*
95 * unsetenv(name) --
96 * Delete environmental variable "name".
97 */
98 int
unsetenv(const char * name)99 unsetenv(const char *name)
100 {
101 char **P;
102 int offset;
103
104 if ((name == NULL) || (*name == '\0') || strchr(name, '=')) {
105 errno = EINVAL;
106 return (-1);
107 }
108
109 while (__findenv(name, &offset)) /* if set multiple times */
110 for (P = &environ[offset];; ++P)
111 if (!(*P = *(P + 1)))
112 break;
113 return (0);
114 }
115