/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1991, 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 <capsicum_helpers.h>
#include <err.h>
#include <libgen.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wchar.h>

void stripsuffix(char *, const char *, size_t);
void usage(void);

int
main(int argc, char **argv)
{
        char *p, *suffix;
        size_t suffixlen;
        int aflag, ch;

        setlocale(LC_ALL, "");

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

        aflag = 0;
        suffix = NULL;
        suffixlen = 0;

        while ((ch = getopt(argc, argv, "as:")) != -1)
                switch(ch) {
                case 'a':
                        aflag = 1;
                        break;
                case 's':
                        suffix = optarg;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc < 1)
                usage();

        if (!*argv[0]) {
                printf("\n");
                exit(0);
        }
        if ((p = basename(argv[0])) == NULL)
                err(1, "%s", argv[0]);
        if ((suffix == NULL && !aflag) && argc == 2) {
                suffix = argv[1];
                argc--;
        }
        if (suffix != NULL)
                suffixlen = strlen(suffix);
        while (argc--) {
                if ((p = basename(*argv)) == NULL)
                        err(1, "%s", argv[0]);
                stripsuffix(p, suffix, suffixlen);
                argv++;
                (void)printf("%s\n", p);
        }
        exit(0);
}

void
stripsuffix(char *p, const char *suffix, size_t suffixlen)
{
        char *q, *r;
        mbstate_t mbs;
        size_t n;

        if (suffixlen && (q = strchr(p, '\0') - suffixlen) > p &&
            strcmp(suffix, q) == 0) {
                /* Ensure that the match occurred on a character boundary. */
                memset(&mbs, 0, sizeof(mbs));
                for (r = p; r < q; r += n) {
                        n = mbrlen(r, MB_LEN_MAX, &mbs);
                        if (n == (size_t)-1 || n == (size_t)-2) {
                                memset(&mbs, 0, sizeof(mbs));
                                n = 1;
                        }
                }
                /* Chop off the suffix. */
                if (q == r)
                        *q = '\0';
        }
}

void
usage(void)
{

        (void)fprintf(stderr,
"usage: basename string [suffix]\n"
"       basename [-a] [-s suffix] string [...]\n");
        exit(1);
}