/*	$NetBSD: setenv.c,v 1.1.1.1 2009/04/12 15:33:26 christos Exp $	*/

#if defined(LIBC_SCCS) && !defined(lint)

static const char sccsid[] = "@(#)setenv.c	8.1 (Berkeley) 6/4/93";

static const char rcsid[] = "Id: setenv.c,v 1.2 2005/04/27 04:56:11 sra Exp";

#endif /* LIBC_SCCS and not lint */

/*

 * 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. 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.

 */

/*

 * Per the statement at http://opensource.org/licenses/bsd-license.php,

 *

 *	The advertising clause in the license appearing on BSD Unix files was

 *	officially rescinded by the Director of the Office of Technology

 *	Licensing of the University of California on July 22 1999. He states

 *	that clause 3 is "hereby deleted in its entirety."

 *

 * I removed the advertising clause in the above copyright.

 * The above web site points to

 * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change.

 *

 * Arnold Robbins

 * 7 September 2016

 */

/* #include "port_before.h" */

#include <stddef.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

/* #include "port_after.h" */

#define NEED_SETENV

#if !defined(NEED_SETENV)

int __bindcompat_setenv;

#else

/*

 * Gawk changes:

 * 1. Comment out "port_before.h" and "port_after.h" includes.

 * 2. Define NEED_SETENV.

 * 3. Add leading "int" to setenv() for C99 compilers. Which is worse,

 *    that it wasn't there in the first place, or that C99 now makes

 *    such functions void, breaking 40+ years of historical practice?

 * 4. Change return type of unsetenv to "int" for standards

 *    conformance and check for name containing an "=" in

 *    which case it return an error. (See unsetenv(3), at least on Linux.)

 */

extern char **environ;

static char *findenv(const char *name, int *offset);

/*%

 * setenv --

 *	Set the value of the environmental variable "name" to be

 *	"value".  If rewrite is set, replace any current value.

 */

int

setenv(const char *name, const char *value, int rewrite)

{

	extern char **environ;

	static int alloced;			/*%< if allocated space before */

	char *c;

	int l_value, offset;

	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 */

		int cnt;

		char **p;

		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);

}

/*%

 * unsetenv(name) --

 *	Delete environmental variable "name".

 */

int

unsetenv(const char *name)

{

	char **p;

	int offset;

	if (strchr(name, '=') != NULL) {

		errno = EINVAL;

		return -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.

 */

static char *

findenv(const char *name, int *offset)

{

	const char *np;

	char **p, *c;

	int len;

	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);

}

#endif

/*! \file */