/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 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 <sys/param.h>
#include <sys/stat.h>

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

static volatile sig_atomic_t siginfo;

static void usage(void) __dead2;
static int may_have_nfs4acl(const FTSENT *ent, int hflag);

static void
siginfo_handler(int sig __unused)
{

        siginfo = 1;
}

int
main(int argc, char *argv[])
{
        FTS *ftsp;
        FTSENT *p;
        mode_t *set;
        int Hflag, Lflag, Rflag, ch, fflag, fts_options, hflag, rval;
        int vflag;
        char *mode;
        mode_t newmode;

        set = NULL;
        Hflag = Lflag = Rflag = fflag = hflag = vflag = 0;
        while ((ch = getopt(argc, argv, "HLPRXfghorstuvwx")) != -1)
                switch (ch) {
                case 'H':
                        Hflag = 1;
                        Lflag = 0;
                        break;
                case 'L':
                        Lflag = 1;
                        Hflag = 0;
                        break;
                case 'P':
                        Hflag = Lflag = 0;
                        break;
                case 'R':
                        Rflag = 1;
                        break;
                case 'f':
                        fflag = 1;
                        break;
                case 'h':
                        /*
                         * In System V the -h option causes chmod to change
                         * the mode of the symbolic link. 4.4BSD's symbolic
                         * links didn't have modes, so it was an undocumented
                         * noop.  In FreeBSD 3.0, lchmod(2) is introduced and
                         * this option does real work.
                         */
                        hflag = 1;
                        break;
                /*
                 * XXX
                 * "-[rwx]" are valid mode commands.  If they are the entire
                 * argument, getopt has moved past them, so decrement optind.
                 * Regardless, we're done argument processing.
                 */
                case 'g': case 'o': case 'r': case 's':
                case 't': case 'u': case 'w': case 'X': case 'x':
                        if (argv[optind - 1][0] == '-' &&
                            argv[optind - 1][1] == ch &&
                            argv[optind - 1][2] == '\0')
                                --optind;
                        goto done;
                case 'v':
                        vflag++;
                        break;
                case '?':
                default:
                        usage();
                }
done:   argv += optind;
        argc -= optind;

        if (argc < 2)
                usage();

        (void)signal(SIGINFO, siginfo_handler);

        if (Rflag) {
                if (hflag)
                        errx(1, "the -R and -h options may not be "
                            "specified together.");
                if (Lflag) {
                        fts_options = FTS_LOGICAL;
                } else {
                        fts_options = FTS_PHYSICAL;

                        if (Hflag) {
                                fts_options |= FTS_COMFOLLOW;
                        }
                }
        } else if (hflag) {
                fts_options = FTS_PHYSICAL;
        } else {
                fts_options = FTS_LOGICAL;
        }

        mode = *argv;
        if ((set = setmode(mode)) == NULL)
                errx(1, "invalid file mode: %s", mode);

        if ((ftsp = fts_open(++argv, fts_options, 0)) == NULL)
                err(1, "fts_open");
        for (rval = 0; errno = 0, (p = fts_read(ftsp)) != NULL;) {
                int atflag;

                if ((fts_options & FTS_LOGICAL) ||
                    ((fts_options & FTS_COMFOLLOW) &&
                    p->fts_level == FTS_ROOTLEVEL))
                        atflag = 0;
                else
                        atflag = AT_SYMLINK_NOFOLLOW;

                switch (p->fts_info) {
                case FTS_D:
                        if (!Rflag)
                                fts_set(ftsp, p, FTS_SKIP);
                        break;
                case FTS_DNR:                   /* Warn, chmod. */
                        warnx("%s: %s", p->fts_path, strerror(p->fts_errno));
                        rval = 1;
                        break;
                case FTS_DP:                    /* Already changed at FTS_D. */
                        continue;
                case FTS_ERR:                   /* Warn, continue. */
                case FTS_NS:
                        warnx("%s: %s", p->fts_path, strerror(p->fts_errno));
                        rval = 1;
                        continue;
                default:
                        break;
                }
                newmode = getmode(set, p->fts_statp->st_mode);
                /*
                 * With NFSv4 ACLs, it is possible that applying a mode
                 * identical to the one computed from an ACL will change
                 * that ACL.
                 */
                if (may_have_nfs4acl(p, hflag) == 0 &&
                    (newmode & ALLPERMS) == (p->fts_statp->st_mode & ALLPERMS))
                                continue;
                if (fchmodat(AT_FDCWD, p->fts_accpath, newmode, atflag) == -1
                    && !fflag) {
                        warn("%s", p->fts_path);
                        rval = 1;
                } else if (vflag || siginfo) {
                        (void)printf("%s", p->fts_path);

                        if (vflag > 1 || siginfo) {
                                char m1[12], m2[12];

                                strmode(p->fts_statp->st_mode, m1);
                                strmode((p->fts_statp->st_mode &
                                    S_IFMT) | newmode, m2);
                                (void)printf(": 0%o [%s] -> 0%o [%s]",
                                    p->fts_statp->st_mode, m1,
                                    (p->fts_statp->st_mode & S_IFMT) |
                                    newmode, m2);
                        }
                        (void)printf("\n");
                        siginfo = 0;
                }
        }
        if (errno)
                err(1, "fts_read");
        exit(rval);
}

static void
usage(void)
{
        (void)fprintf(stderr,
            "usage: chmod [-fhv] [-R [-H | -L | -P]] mode file ...\n");
        exit(1);
}

static int
may_have_nfs4acl(const FTSENT *ent, int hflag)
{
        int ret;
        static dev_t previous_dev = NODEV;
        static int supports_acls = -1;

        if (previous_dev != ent->fts_statp->st_dev) {
                previous_dev = ent->fts_statp->st_dev;
                supports_acls = 0;

                if (hflag)
                        ret = lpathconf(ent->fts_accpath, _PC_ACL_NFS4);
                else
                        ret = pathconf(ent->fts_accpath, _PC_ACL_NFS4);
                if (ret > 0)
                        supports_acls = 1;
                else if (ret < 0 && errno != EINVAL)
                        warn("%s", ent->fts_path);
        }

        return (supports_acls);
}