/*      $OpenBSD: env.c,v 1.19 2024/07/28 21:44:42 kn Exp $     */

/*
 * Copyright (c) 1988, 1993, 1994
 *      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 <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static void __dead usage(void);

int
main(int argc, char *argv[])
{
        extern char **environ;
        extern int optind;
        char **ep, *p;
        int ch;

        if (pledge("stdio exec", NULL) == -1)
                err(1, "pledge");

        while ((ch = getopt(argc, argv, "iu:-")) != -1)
                switch(ch) {
                case '-':                       /* obsolete */
                case 'i':
                        if ((environ = calloc(1, sizeof(char *))) == NULL)
                                err(126, "calloc");
                        break;
                case 'u':
                        if (unsetenv(optarg) == -1)
                                err(126, "unsetenv");
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        for (; *argv && (p = strchr(*argv, '=')); ++argv) {
                *p++ = '\0';
                if (setenv(*argv, p, 1) == -1) {
                        /* reuse 126, it matches the problem most */
                        err(126, "setenv");
                }
        }

        if (*argv) {
                /*
                 * return 127 if the command to be run could not be
                 * found; 126 if the command was found but could
                 * not be invoked
                 */
                execvp(*argv, argv);
                err((errno == ENOENT) ? 127 : 126, "%s", *argv);
        }

        for (ep = environ; *ep; ep++)
                (void)printf("%s\n", *ep);

        return 0;
}

static void __dead
usage(void)
{
        extern char *__progname;

        (void)fprintf(stderr, "usage: %s [-i] [-u name] [name=value ...] "
            "[utility [argument ...]]\n", __progname);
        exit(1);
}