/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ken Smith of The State University of New York at Buffalo.
 *
 * 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/acl.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <limits.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

/* Exit code for a failed exec. */
#define EXEC_FAILED 127

static int      fflg, hflg, iflg, nflg, vflg;

static int      copy(const char *, const char *);
static int      do_move(const char *, const char *);
static int      fastcopy(const char *, const char *, struct stat *);
static void     usage(void);
static void     preserve_fd_acls(int, int, const char *, const char *);

int
main(int argc, char *argv[])
{
        char path[PATH_MAX];
        struct stat sb;
        char *p, *endp;
        size_t baselen, len;
        int ch, rval;

        while ((ch = getopt(argc, argv, "fhinv")) != -1)
                switch (ch) {
                case 'h':
                        hflg = 1;
                        break;
                case 'i':
                        iflg = 1;
                        fflg = nflg = 0;
                        break;
                case 'f':
                        fflg = 1;
                        iflg = nflg = 0;
                        break;
                case 'n':
                        nflg = 1;
                        fflg = iflg = 0;
                        break;
                case 'v':
                        vflg = 1;
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc < 2)
                usage();

        /*
         * If the stat on the target fails or the target isn't a directory,
         * try the move.  More than 2 arguments is an error in this case.
         */
        if (stat(argv[argc - 1], &sb) || !S_ISDIR(sb.st_mode)) {
                if (argc > 2)
                        errx(1, "%s is not a directory", argv[argc - 1]);
                exit(do_move(argv[0], argv[1]));
        }

        /*
         * If -h was specified, treat the target as a symlink instead of
         * directory.
         */
        if (hflg) {
                if (argc > 2)
                        usage();
                if (lstat(argv[1], &sb) == 0 && S_ISLNK(sb.st_mode))
                        exit(do_move(argv[0], argv[1]));
        }

        /* It's a directory, move each file into it. */
        if (strlen(argv[argc - 1]) > sizeof(path) - 1)
                errx(1, "%s: destination pathname too long", *argv);
        (void)strcpy(path, argv[argc - 1]);
        baselen = strlen(path);
        endp = &path[baselen];
        if (!baselen || *(endp - 1) != '/') {
                *endp++ = '/';
                ++baselen;
        }
        for (rval = 0; --argc; ++argv) {
                /*
                 * Find the last component of the source pathname.  It
                 * may have trailing slashes.
                 */
                p = *argv + strlen(*argv);
                while (p != *argv && p[-1] == '/')
                        --p;
                while (p != *argv && p[-1] != '/')
                        --p;

                if ((baselen + (len = strlen(p))) >= PATH_MAX) {
                        warnx("%s: destination pathname too long", *argv);
                        rval = 1;
                } else {
                        memmove(endp, p, (size_t)len + 1);
                        if (do_move(*argv, path))
                                rval = 1;
                }
        }
        exit(rval);
}

static int
do_move(const char *from, const char *to)
{
        char path[PATH_MAX], modep[15];
        struct statfs sfs;
        struct stat sb;
        int ask, ch, first;

        /*
         * Check access.  If interactive and file exists, ask user if it
         * should be replaced.  Otherwise if file exists but isn't writable
         * make sure the user wants to clobber it.
         */
        if (!fflg && !access(to, F_OK)) {
                /* prompt only if source exists */
                if (lstat(from, &sb) == -1) {
                        warn("%s", from);
                        return (1);
                }

#define YESNO "(y/n [n]) "
                ask = 0;
                if (nflg) {
                        if (vflg)
                                printf("%s not overwritten\n", to);
                        return (0);
                } else if (iflg) {
                        (void)fprintf(stderr, "overwrite %s? %s", to, YESNO);
                        ask = 1;
                } else if (access(to, W_OK) && !stat(to, &sb) && isatty(STDIN_FILENO)) {
                        strmode(sb.st_mode, modep);
                        (void)fprintf(stderr, "override %s%s%s/%s for %s? %s",
                            modep + 1, modep[9] == ' ' ? "" : " ",
                            user_from_uid((unsigned long)sb.st_uid, 0),
                            group_from_gid((unsigned long)sb.st_gid, 0), to, YESNO);
                        ask = 1;
                }
                if (ask) {
                        first = ch = getchar();
                        while (ch != '\n' && ch != EOF)
                                ch = getchar();
                        if (first != 'y' && first != 'Y') {
                                (void)fprintf(stderr, "not overwritten\n");
                                return (0);
                        }
                }
        }
        /*
         * Rename on FreeBSD will fail with EISDIR and ENOTDIR, before failing
         * with EXDEV.  Therefore, copy() doesn't have to perform the checks
         * specified in the Step 3 of the POSIX mv specification.
         */
        if (!rename(from, to)) {
                if (vflg)
                        printf("%s -> %s\n", from, to);
                return (0);
        }

        if (errno == EXDEV) {
                /*
                 * If the source is a symbolic link and is on another
                 * filesystem, it can be recreated at the destination.
                 */
                if (lstat(from, &sb) == -1) {
                        warn("%s", from);
                        return (1);
                }
                if (!S_ISLNK(sb.st_mode)) {
                        /* Can't mv(1) a mount point. */
                        if (realpath(from, path) == NULL) {
                                warn("cannot resolve %s: %s", from, path);
                                return (1);
                        }
                        if (!statfs(path, &sfs) &&
                            !strcmp(path, sfs.f_mntonname)) {
                                warnx("cannot rename a mount point");
                                return (1);
                        }
                }
        } else {
                warn("rename %s to %s", from, to);
                return (1);
        }

        /*
         * If rename fails because we're trying to cross devices, and
         * it's a regular file, do the copy internally; otherwise, use
         * cp and rm.
         */
        if (lstat(from, &sb)) {
                warn("%s", from);
                return (1);
        }
        return (S_ISREG(sb.st_mode) ?
            fastcopy(from, to, &sb) : copy(from, to));
}

static int
fastcopy(const char *from, const char *to, struct stat *sbp)
{
        struct timespec ts[2];
        struct stat tsb;
        static char *bp = NULL;
        static size_t blen = MAXPHYS;
        ssize_t nread;
        int from_fd, to_fd;
        mode_t oldmode;

        if ((from_fd = open(from, O_RDONLY, 0)) < 0) {
                warn("fastcopy: open() failed (from): %s", from);
                return (1);
        }
        if (bp == NULL && (bp = malloc(blen)) == NULL) {
                warnx("malloc(%zu) failed", blen);
                (void)close(from_fd);
                return (1);
        }
        while ((to_fd =
            open(to, O_CREAT | O_EXCL | O_TRUNC | O_WRONLY, 0)) < 0) {
                if (errno == EEXIST && unlink(to) == 0)
                        continue;
                warn("fastcopy: open() failed (to): %s", to);
                (void)close(from_fd);
                return (1);
        }
        while ((nread = read(from_fd, bp, blen)) > 0)
                if (write(to_fd, bp, (size_t)nread) != nread) {
                        warn("fastcopy: write() failed: %s", to);
                        goto err;
                }
        if (nread < 0) {
                warn("fastcopy: read() failed: %s", from);
err:            if (unlink(to))
                        warn("%s: remove", to);
                (void)close(from_fd);
                (void)close(to_fd);
                return (1);
        }

        oldmode = sbp->st_mode & ALLPERMS;
        if (fchown(to_fd, sbp->st_uid, sbp->st_gid)) {
                warn("%s: set owner/group (was: %lu/%lu)", to,
                    (u_long)sbp->st_uid, (u_long)sbp->st_gid);
                if (oldmode & (S_ISUID | S_ISGID)) {
                        warnx("%s: owner/group changed; "
                            "clearing suid/sgid (mode was 0%03o)",
                            to, oldmode);
                        sbp->st_mode &= ~(S_ISUID | S_ISGID);
                }
        }
        if (fchmod(to_fd, sbp->st_mode))
                warn("%s: set mode (was: 0%03o)", to, oldmode);
        /*
         * POSIX 1003.2c states that if _POSIX_ACL_EXTENDED is in effect
         * for dest_file, then its ACLs shall reflect the ACLs of the
         * source_file.
         */
        preserve_fd_acls(from_fd, to_fd, from, to);
        (void)close(from_fd);

        ts[0] = sbp->st_atim;
        ts[1] = sbp->st_mtim;
        if (futimens(to_fd, ts))
                warn("%s: set times", to);

        /*
         * XXX
         * NFS doesn't support chflags; ignore errors unless there's reason
         * to believe we're losing bits.  (Note, this still won't be right
         * if the server supports flags and we were trying to *remove* flags
         * on a file that we copied, i.e., that we didn't create.)
         */
        if (fstat(to_fd, &tsb) == 0) {
                if ((sbp->st_flags  & ~UF_ARCHIVE) !=
                    (tsb.st_flags & ~UF_ARCHIVE)) {
                        if (fchflags(to_fd,
                            sbp->st_flags | (tsb.st_flags & UF_ARCHIVE)))
                                if (errno != EOPNOTSUPP ||
                                    ((sbp->st_flags & ~UF_ARCHIVE) != 0))
                                        warn("%s: set flags (was: 0%07o)",
                                            to, sbp->st_flags);
                }
        } else
                warn("%s: cannot stat", to);

        if (close(to_fd)) {
                warn("%s", to);
                return (1);
        }

        if (unlink(from)) {
                warn("%s: remove", from);
                return (1);
        }
        if (vflg)
                printf("%s -> %s\n", from, to);
        return (0);
}

static int
copy(const char *from, const char *to)
{
        struct stat sb;
        int pid, status;

        if (lstat(to, &sb) == 0) {
                /* Destination path exists. */
                if (S_ISDIR(sb.st_mode)) {
                        if (rmdir(to) != 0) {
                                warn("rmdir %s", to);
                                return (1);
                        }
                } else {
                        if (unlink(to) != 0) {
                                warn("unlink %s", to);
                                return (1);
                        }
                }
        } else if (errno != ENOENT) {
                warn("%s", to);
                return (1);
        }

        /* Copy source to destination. */
        if (!(pid = vfork())) {
                execl(_PATH_CP, "mv", vflg ? "-PRpv" : "-PRp", "--", from, to,
                    (char *)NULL);
                _exit(EXEC_FAILED);
        }
        if (waitpid(pid, &status, 0) == -1) {
                warn("%s %s %s: waitpid", _PATH_CP, from, to);
                return (1);
        }
        if (!WIFEXITED(status)) {
                warnx("%s %s %s: did not terminate normally",
                    _PATH_CP, from, to);
                return (1);
        }
        switch (WEXITSTATUS(status)) {
        case 0:
                break;
        case EXEC_FAILED:
                warnx("%s %s %s: exec failed", _PATH_CP, from, to);
                return (1);
        default:
                warnx("%s %s %s: terminated with %d (non-zero) status",
                    _PATH_CP, from, to, WEXITSTATUS(status));
                return (1);
        }

        /* Delete the source. */
        if (!(pid = vfork())) {
                execl(_PATH_RM, "mv", "-rf", "--", from, (char *)NULL);
                _exit(EXEC_FAILED);
        }
        if (waitpid(pid, &status, 0) == -1) {
                warn("%s %s: waitpid", _PATH_RM, from);
                return (1);
        }
        if (!WIFEXITED(status)) {
                warnx("%s %s: did not terminate normally", _PATH_RM, from);
                return (1);
        }
        switch (WEXITSTATUS(status)) {
        case 0:
                break;
        case EXEC_FAILED:
                warnx("%s %s: exec failed", _PATH_RM, from);
                return (1);
        default:
                warnx("%s %s: terminated with %d (non-zero) status",
                    _PATH_RM, from, WEXITSTATUS(status));
                return (1);
        }
        return (0);
}

static void
preserve_fd_acls(int source_fd, int dest_fd, const char *source_path,
    const char *dest_path)
{
        acl_t acl;
        acl_type_t acl_type;
        int acl_supported = 0, ret, trivial;

        ret = fpathconf(source_fd, _PC_ACL_NFS4);
        if (ret > 0 ) {
                acl_supported = 1;
                acl_type = ACL_TYPE_NFS4;
        } else if (ret < 0 && errno != EINVAL) {
                warn("fpathconf(..., _PC_ACL_NFS4) failed for %s",
                    source_path);
                return;
        }
        if (acl_supported == 0) {
                ret = fpathconf(source_fd, _PC_ACL_EXTENDED);
                if (ret > 0 ) {
                        acl_supported = 1;
                        acl_type = ACL_TYPE_ACCESS;
                } else if (ret < 0 && errno != EINVAL) {
                        warn("fpathconf(..., _PC_ACL_EXTENDED) failed for %s",
                            source_path);
                        return;
                }
        }
        if (acl_supported == 0)
                return;

        acl = acl_get_fd_np(source_fd, acl_type);
        if (acl == NULL) {
                warn("failed to get acl entries for %s", source_path);
                return;
        }
        if (acl_is_trivial_np(acl, &trivial)) {
                warn("acl_is_trivial() failed for %s", source_path);
                acl_free(acl);
                return;
        }
        if (trivial) {
                acl_free(acl);
                return;
        }
        if (acl_set_fd_np(dest_fd, acl, acl_type) < 0) {
                warn("failed to set acl entries for %s", dest_path);
                acl_free(acl);
                return;
        }
        acl_free(acl);
}

static void
usage(void)
{
        (void)fprintf(stderr, "%s\n%s\n",
            "usage: mv [-f | -i | -n] [-hv] source target",
            "       mv [-f | -i | -n] [-v] source ... directory");
        exit(EX_USAGE);
}