2 * Copyright (c) 1987, 1993
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33 * @(#)setenv.c 8.1 (Berkeley) 6/4/93
34 * $FreeBSD: src/lib/libc/stdlib/setenv.c,v 1.5.2.1 2000/09/20 19:46:03 brian Exp $
35 * $DragonFly: src/lib/libc/stdlib/setenv.c,v 1.5 2005/04/28 13:51:55 joerg Exp $
42 extern char **environ;
44 char *__findenv (const char *, size_t *);
48 * Set the value of the environmental variable "name" to be
49 * "value". If rewrite is set, replace any current value.
52 setenv(const char *name, const char *value, int rewrite)
54 static char **alloced; /* if allocated space before */
56 size_t l_value, offset;
58 if (*value == '=') /* no `=' in value */
60 l_value = strlen(value);
61 if ((c = __findenv(name, &offset))) { /* find if already exists */
64 if (strlen(c) >= l_value) { /* old larger; copy over */
65 while ( (*c++ = *value++) );
68 } else { /* create new slot */
72 for (p = environ, cnt = 0; *p; ++p, ++cnt);
73 if (alloced == environ) {
74 /* just increase size */
75 p = realloc(environ, sizeof(char *) * (cnt + 2));
78 alloced = environ = p;
80 else { /* get new space */
81 /* copy old entries into it */
82 p = malloc(sizeof(char *) * (cnt + 2));
85 bcopy(environ, p, cnt * sizeof(char *));
86 alloced = environ = p;
88 environ[cnt + 1] = NULL;
91 for (c = (char *)name; *c && *c != '='; ++c); /* no `=' in name */
92 if (!(environ[offset] = /* name + `=' + value */
93 malloc((size_t)((int)(c - name) + l_value + 2))))
95 for (c = environ[offset]; (*c = *name++) && *c != '='; ++c);
96 for (*c++ = '='; (*c++ = *value++); );
102 * Delete environmental variable "name".
105 unsetenv(const char *name)
110 while (__findenv(name, &offset)) /* if set multiple times */
111 for (p = &environ[offset];; ++p)
112 if (!(*p = *(p + 1)))