setenv.c - vx32 - Local 9vx git repository for patches.
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setenv.c (3752B)
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1 /*
2 * Copyright (c) 1987, 1993
3 * The Regents of the University of California. 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 <stddef.h>
35 #include <stdlib.h>
36 #include <string.h>
37
38 char *__findenv(const char *, int *);
39
40 /*
41 * setenv --
42 * Set the value of the environmental variable "name" to be
43 * "value". If rewrite is set, replace any current value.
44 */
45 int
46 setenv(name, value, rewrite)
47 const char *name;
48 const char *value;
49 int rewrite;
50 {
51 extern char **environ;
52 static char **alloced; /* if allocated space before */
53 char *c;
54 int l_value, offset;
55
56 if (*value == '=') /* no `=' in value */
57 ++value;
58 l_value = strlen(value);
59 if ((c = __findenv(name, &offset))) { /* find if already exists */
60 if (!rewrite)
61 return (0);
62 if (strlen(c) >= l_value) { /* old larger; copy over */
63 while ( (*c++ = *value++) );
64 return (0);
65 }
66 } else { /* create new slot */
67 int cnt;
68 char **p;
69
70 for (p = environ, cnt = 0; *p; ++p, ++cnt);
71 if (alloced == environ) { /* just increase size */
72 p = (char **)realloc((char *)environ,
73 (size_t)(sizeof(char *) * (cnt + 2)));
74 if (!p)
75 return (-1);
76 alloced = environ = p;
77 }
78 else { /* get new space */
79 /* copy old entries into it */
80 p = malloc((size_t)(sizeof(char *) * (cnt + 2)));
81 if (!p)
82 return (-1);
83 memcpy(p, environ, cnt * sizeof(char *));
84 alloced = environ = p;
85 }
86 environ[cnt + 1] = NULL;
87 offset = cnt;
88 }
89 for (c = (char *)name; *c && *c != '='; ++c); /* no `=' in name */
90 if (!(environ[offset] = /* name + `=' + value */
91 malloc((size_t)((int)(c - name) + l_value + 2))))
92 return (-1);
93 for (c = environ[offset]; (*c = *name++) && *c != '='; ++c);
94 for (*c++ = '='; (*c++ = *value++); );
95 return (0);
96 }
97
98 /*
99 * unsetenv(name) --
100 * Delete environmental variable "name".
101 */
102 int
103 unsetenv(name)
104 const char *name;
105 {
106 extern char **environ;
107 char **p;
108 int offset;
109
110 while (__findenv(name, &offset)) /* if set multiple times */
111 for (p = &environ[offset];; ++p)
112 if (!(*p = *(p + 1)))
113 break;
114 return 0;
115 }