+/*
+ * Copyright (c) 1987, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
-#include <stdlib.h>
-#include <string.h>
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)setenv.c 8.1 (Berkeley) 6/4/93";
+#endif /* LIBC_SCCS and not lint */
-int
-setenv(const char *name, const char *val, int overwrite)
+#include <errno.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+
+char *__findenv(const char *, int *);
+
+/*
+ * setenv --
+ * Set the value of the environmental variable "name" to be
+ * "value". If rewrite is set, replace any current value.
+ */
+setenv(name, value, rewrite)
+ register const char *name;
+ register const char *value;
+ int rewrite;
{
- char *bf;
- int r;
+ extern char **environ;
+ static int alloced; /* if allocated space before */
+ register char *c;
+ int l_value, offset;
- if(!overwrite && getenv(name))
- return 0;
+ if (*value == '=') /* no `=' in value */
+ ++value;
+ l_value = strlen(value);
+ if ((c = __findenv(name, &offset))) { /* find if already exists */
+ if (!rewrite)
+ return (0);
+ if (strlen(c) >= l_value) { /* old larger; copy over */
+ while (*c++ = *value++);
+ return (0);
+ }
+ } else { /* create new slot */
+ register int cnt;
+ register char **p;
- if(!(bf=malloc(strlen(name)+strlen(val)+2)))
- return -1;
+ for (p = environ, cnt = 0; *p; ++p, ++cnt);
+ if (alloced) { /* just increase size */
+ environ = (char **)realloc((char *)environ,
+ (size_t)(sizeof(char *) * (cnt + 2)));
+ if (!environ)
+ return (-1);
+ }
+ else { /* get new space */
+ alloced = 1; /* copy old entries into it */
+ p = malloc((size_t)(sizeof(char *) * (cnt + 2)));
+ if (!p)
+ return (-1);
+ memcpy(p, environ, cnt * sizeof(char *));
+ environ = p;
+ }
+ environ[cnt + 1] = NULL;
+ offset = cnt;
+ }
+ for (c = (char *)name; *c && *c != '='; ++c); /* no `=' in name */
+ if (!(environ[offset] = /* name + `=' + value */
+ malloc((size_t)((int)(c - name) + l_value + 2))))
+ return (-1);
+ for (c = environ[offset]; (*c = *name++) && *c != '='; ++c);
+ for (*c++ = '='; *c++ = *value++;);
+ return (0);
+}
- strcpy(bf, name);
- strcat(bf, "=");
- strcat(bf, val);
+/*
+ * unsetenv(name) --
+ * Delete environmental variable "name".
+ */
+int
+unsetenv(name)
+ const char *name;
+{
+ extern char **environ;
+ register char **p;
+ int offset;
- r = putenv(bf);
+ if (name == NULL || strlen(name) == 0 || strchr(name, '=') != 0)
+ {
+ errno= EINVAL;
+ return -1;
+ }
- return r == 0 ? 0 : -1;
+ while (__findenv(name, &offset)) /* if set multiple times */
+ for (p = &environ[offset];; ++p)
+ if (!(*p = *(p + 1)))
+ break;
+ return 0;
}
+/*
+ * __findenv --
+ * Returns pointer to value associated with name, if any, else NULL.
+ * Sets offset to be the offset of the name/value combination in the
+ * environmental array, for use by setenv(3) and unsetenv(3).
+ * Explicitly removes '=' in argument name.
+ *
+ * This routine *should* be a static; don't use it.
+ */
+char *
+__findenv(name, offset)
+ register const char *name;
+ int *offset;
+{
+ extern char **environ;
+ register int len;
+ register const char *np;
+ register char **p, *c;
+
+ if (name == NULL || environ == NULL)
+ return (NULL);
+ for (np = name; *np && *np != '='; ++np)
+ continue;
+ len = np - name;
+ for (p = environ; (c = *p) != NULL; ++p)
+ if (strncmp(c, name, len) == 0 && c[len] == '=') {
+ *offset = p - environ;
+ return (c + len + 1);
+ }
+ return (NULL);
+}
+/*
+ * $PchId: setenv.c,v 1.3 1996/05/09 20:43:02 philip Exp philip $
+ */
