/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2002 Tim J. Robbins.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

/*
 * pathchk -- check pathnames
 *
 * Check whether files could be created with the names specified on the
 * command line. If -p is specified, check whether the pathname is portable
 * to all POSIX systems.
 */

#include <sys/types.h>
#include <sys/stat.h>

#include <err.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static int       check(const char *);
static int       portable(const char *);
static void      usage(void);

static int       pflag;                 /* Perform portability checks */
static int       Pflag;                 /* Check for empty paths, leading '-' */

int
main(int argc, char *argv[])
{
        int ch, rval;
        const char *arg;

        while ((ch = getopt(argc, argv, "pP")) > 0) {
                switch (ch) {
                case 'p':
                        pflag = 1;
                        break;
                case 'P':
                        Pflag = 1;
                        break;
                default:
                        usage();
                        /*NOTREACHED*/
                }
        }
        argc -= optind;
        argv += optind;

        if (argc == 0)
                usage();

        rval = 0;
        while ((arg = *argv++) != NULL)
                rval |= check(arg);

        exit(rval);
}

static void
usage(void)
{

        fprintf(stderr, "usage: pathchk [-Pp] pathname ...\n");
        exit(1);
}

static int
check(const char *path)
{
        struct stat sb;
        long complen, namemax, pathmax, svnamemax;
        int last;
        char *end, *p, *pathd;

        if ((pathd = strdup(path)) == NULL)
                err(1, "strdup");

        p = pathd;

        if (Pflag && *p == '\0') {
                warnx("%s: empty pathname", path);
                goto bad;
        }
        if ((Pflag || pflag) && (*p == '-' || strstr(p, "/-") != NULL)) {
                warnx("%s: contains a component starting with '-'", path);
                goto bad;
        }

        if (!pflag) {
                errno = 0;
                namemax = pathconf(*p == '/' ? "/" : ".", _PC_NAME_MAX);
                if (namemax == -1 && errno != 0)
                        namemax = NAME_MAX;
        } else
                namemax = _POSIX_NAME_MAX;

        for (;;) {
                p += strspn(p, "/");
                complen = (long)strcspn(p, "/");
                end = p + complen;
                last = *end == '\0';
                *end = '\0';

                if (namemax != -1 && complen > namemax) {
                        warnx("%s: %s: component too long (limit %ld)", path,
                            p, namemax);
                        goto bad;
                }

                if (!pflag && stat(pathd, &sb) == -1 && errno != ENOENT) {
                        warn("%s: %.*s", path, (int)(strlen(pathd) -
                            complen - 1), pathd);
                        goto bad;
                }

                if (pflag && !portable(p)) {
                        warnx("%s: %s: component contains non-portable "
                            "character", path, p);
                        goto bad;
                }

                if (last)
                        break;

                if (!pflag) {
                        errno = 0;
                        svnamemax = namemax;
                        namemax = pathconf(pathd, _PC_NAME_MAX);
                        if (namemax == -1 && errno != 0)
                                namemax = svnamemax;
                }

                *end = '/';
                p = end + 1;
        }

        if (!pflag) {
                errno = 0;
                pathmax = pathconf(path, _PC_PATH_MAX);
                if (pathmax == -1 && errno != 0)
                        pathmax = PATH_MAX;
        } else
                pathmax = _POSIX_PATH_MAX;
        if (pathmax != -1 && strlen(path) >= (size_t)pathmax) {
                warnx("%s: path too long (limit %ld)", path, pathmax - 1);
                goto bad;
        }

        free(pathd);
        return (0);

bad:    free(pathd);
        return (1);
}

/*
 * Check whether a path component contains only portable characters.
 */
static int
portable(const char *path)
{
        static const char charset[] =
            "abcdefghijklmnopqrstuvwxyz"
            "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
            "0123456789._-";
        long s;

        s = strspn(path, charset);
        if (path[s] != '\0')
                return (0);

        return (1);
}