Colony » Colony Scout » Colony Scout OS

/*

 * 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.

 */

#include <stddef.h>

#include <stdlib.h>

#include <string.h>

extern char **environ;

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.

 */

int

setenv(name, value, rewrite)

        const char *name;

        const char *value;

        int rewrite;

{

        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 ((int)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);

                        bcopy(environ, p, 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++) != 0;);

        return (0);

}

/*

 * unsetenv(name) --

 *        Delete environmental variable "name".

 */

void

unsetenv(name)

        const char *name;

{

        char **p;

        int offset;

        while (__findenv(name, &offset))        /* if set multiple times */

                for (p = &environ[offset];; ++p)

                        if (!(*p = *(p + 1)))

                                break;

}