/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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 <sys/types.h>

#include <capsicum_helpers.h>
#include <err.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

extern char **environ;

static void
usage(void)
{
        (void)fprintf(stderr, "usage: printenv [name]\n");
        exit(EXIT_FAILURE);
}

/*
 * printenv
 *
 * Bill Joy, UCB
 * February, 1979
 */
int
main(int argc, char *argv[])
{
        char *cp, **ep;
        size_t len;
        int opt;

        if (caph_limit_stdio() < 0 || caph_enter() < 0)
                err(1, "capsicum");

        while ((opt = getopt(argc, argv, "")) != -1) {
                switch (opt) {
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        if (argc > 1)
                usage();
        if (argc == 0) {
                for (ep = environ; *ep; ep++)
                        (void)printf("%s\n", *ep);
        } else {
                len = strlen(*argv);
                for (ep = environ; *ep != NULL; ep++) {
                        if (memcmp(*ep, *argv, len) == 0) {
                                cp = *ep + len;
                                if (*cp == '=') {
                                        (void)printf("%s\n", cp + 1);
                                        break;
                                }
                        }
                }
                if (*ep == NULL) {
                        /* *argv not found */
                        exit(EXIT_FAILURE);
                }
        }
        if (fflush(stdout) != 0)
                err(EXIT_FAILURE, "stdout");
        exit(EXIT_SUCCESS);
}