1 /* OPENBSD ORIGINAL: lib/libc/stdlib/setenv.c */
4 * Copyright (c) 1987 Regents of the University of California.
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33 #if !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV)
35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char *rcsid = "$OpenBSD: setenv.c,v 1.6 2003/06/02 20:18:38 millert Exp $";
37 #endif /* LIBC_SCCS and not lint */
42 char *__findenv(const char *name, int *offset);
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.
51 * This routine *should* be a static; don't use it.
54 __findenv(name, offset)
55 register const char *name;
58 extern char **environ;
60 register const char *np;
61 register char **p, *cp;
63 if (name == NULL || environ == NULL)
65 for (np = name; *np && *np != '='; ++np)
68 for (p = environ; (cp = *p) != NULL; ++p) {
69 for (np = name, i = len; i && *cp; i--)
72 if (i == 0 && *cp++ == '=') {
73 *offset = p - environ;
83 * Set the value of the environmental variable "name" to be
84 * "value". If rewrite is set, replace any current value.
87 setenv(name, value, rewrite)
88 register const char *name;
89 register const char *value;
92 extern char **environ;
93 static int alloced; /* if allocated space before */
97 if (*value == '=') /* no `=' in value */
99 l_value = strlen(value);
100 if ((C = __findenv(name, &offset))) { /* find if already exists */
103 if (strlen(C) >= l_value) { /* old larger; copy over */
104 while ((*C++ = *value++))
108 } else { /* create new slot */
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)));
120 else { /* get new space */
121 alloced = 1; /* copy old entries into it */
122 P = (char **)malloc((size_t)(sizeof(char *) *
126 memmove(P, environ, cnt * sizeof(char *));
129 environ[cnt + 1] = NULL;
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))))
136 for (C = environ[offset]; (*C = *name++) && *C != '='; ++C)
138 for (*C++ = '='; (*C++ = *value++); )
142 #endif /* HAVE_SETENV */
144 #ifndef HAVE_UNSETENV
147 * Delete environmental variable "name".
153 extern char **environ;
158 while (__findenv(name, &offset)) /* if set multiple times */
159 for (P = &environ[offset];; ++P)
160 if (!(*P = *(P + 1)))
163 #endif /* HAVE_UNSETENV */
165 #endif /* !defined(HAVE_SETENV) || !defined(HAVE_UNSETENV) */