/*      $OpenBSD: mv.c,v 1.47 2021/10/24 21:24:21 deraadt Exp $ */
/*      $NetBSD: mv.c,v 1.9 1995/03/21 09:06:52 cgd Exp $       */

/*
 * 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/time.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/mount.h>

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

extern char *__progname;

int fflg, iflg, vflg;
int stdin_ok;

extern int cpmain(int argc, char **argv);
extern int rmmain(int argc, char **argv);

int     mvcopy(char *, char *);
int     do_move(char *, char *);
int     fastcopy(char *, char *, struct stat *);
void    usage(void);

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

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

        if (argc < 2)
                usage();

        stdin_ok = isatty(STDIN_FILENO);

        /*
         * 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)
                        usage();
                exit(do_move(argv[0], argv[1]));
        }

        /* It's a directory, move each file into it. */
        if (strlcpy(path, argv[argc - 1], sizeof path) >= sizeof path)
                errx(1, "%s: destination pathname too long", *argv);
        baselen = strlen(path);
        endp = &path[baselen];
        if (*(endp - 1) != '/') {
                *endp++ = '/';
                ++baselen;
        }
        for (rval = 0; --argc; ++argv) {
                char *current_arg = *argv;

                /*
                 * Get the name of the file to create from
                 * the argument. This is a bit tricky because
                 * in the case of b/ we actually want b and empty
                 * string
                 */
                if ((p = strrchr(current_arg, '/')) == NULL)
                        p = current_arg;
                else {
                        /* Special case foo/ */
                        if (!*(p+1)) {
                                while (p >= current_arg && *p == '/')
                                        p--;

                                while (p >= current_arg && *p != '/')
                                        p--;
                        }

                        p++;
                }

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

int
do_move(char *from, char *to)
{
        struct stat sb, fsb;
        char modep[15];

        /* Source path must exist (symlink is OK). */
        if (lstat(from, &fsb)) {
                warn("%s", from);
                return (1);
        }

        /*
         * (1)  If the destination path exists, the -f option is not specified
         *      and either of the following conditions are true:
         *
         *      (a) The permissions of the destination path do not permit
         *          writing and the standard input is a terminal.
         *      (b) The -i option is specified.
         *
         *      the mv utility shall write a prompt to standard error and
         *      read a line from standard input.  If the response is not
         *      affirmative, mv shall do nothing more with the current
         *      source file...
         */
        if (!fflg && !access(to, F_OK)) {
                int ask = 1;
                int ch, first;

                if (iflg && !access(from, F_OK)) {
                        (void)fprintf(stderr, "overwrite %s? ", to);
                } else if (stdin_ok && access(to, W_OK) && !stat(to, &sb)) {
                        strmode(sb.st_mode, modep);
                        (void)fprintf(stderr, "override %s%s%s/%s for %s? ",
                            modep + 1, modep[9] == ' ' ? "" : " ",
                            user_from_uid(sb.st_uid, 0),
                            group_from_gid(sb.st_gid, 0), to);
                } else
                        ask = 0;
                if (ask) {
                        first = ch = getchar();
                        while (ch != '\n' && ch != EOF)
                                ch = getchar();
                        if (first != 'y' && first != 'Y')
                                return (0);
                }
        }

        /*
         * (2)  If rename() succeeds, mv shall do nothing more with the
         *      current source file.  If it fails for any other reason than
         *      EXDEV, mv shall write a diagnostic message to the standard
         *      error and do nothing more with the current source file.
         *
         * (3)  If the destination path exists, and it is a file of type
         *      directory and source_file is not a file of type directory,
         *      or it is a file not of type directory, and source file is
         *      a file of type directory, mv shall write a diagnostic
         *      message to standard error, and do nothing more with the
         *      current source file...
         */
        if (!rename(from, to)) {
                if (vflg)
                        (void)fprintf(stdout, "%s -> %s\n", from, to);
                return (0);
        }

        if (errno != EXDEV) {
                warn("rename %s to %s", from, to);
                return (1);
        }

        /* Disallow moving a mount point. */
        if (S_ISDIR(fsb.st_mode)) {
                struct statfs sfs;
                char path[PATH_MAX];

                if (realpath(from, path) == NULL) {
                        warnx("cannot resolve %s", from);
                        return (1);
                }
                if (!statfs(path, &sfs) && !strcmp(path, sfs.f_mntonname)) {
                        warnx("cannot rename a mount point");
                        return (1);
                }
        }

        /*
         * (4)  If the destination path exists, mv shall attempt to remove it.
         *      If this fails for any reason, mv shall write a diagnostic
         *      message to the standard error and do nothing more with the
         *      current source file...
         */
        if (!lstat(to, &sb)) {
                if ((S_ISDIR(sb.st_mode)) ? rmdir(to) : unlink(to)) {
                        warn("can't remove %s", to);
                        return (1);
                }
        }

        /*
         * (5)  The file hierarchy rooted in source_file shall be duplicated
         *      as a file hierarchy rooted in the destination path...
         */
        return (S_ISREG(fsb.st_mode) ?
            fastcopy(from, to, &fsb) : mvcopy(from, to));
}

int
fastcopy(char *from, char *to, struct stat *sbp)
{
        struct timespec ts[2];
        static u_int32_t blen;
        static char *bp;
        int nread, from_fd, to_fd;
        int badchown = 0, serrno = 0;

        if (!blen) {
                blen = sbp->st_blksize;
                if ((bp = malloc(blen)) == NULL) {
                        warn(NULL);
                        blen = 0;
                        return (1);
                }
        }

        if ((from_fd = open(from, O_RDONLY)) == -1) {
                warn("%s", from);
                return (1);
        }
        if ((to_fd = open(to, O_CREAT | O_TRUNC | O_WRONLY, 0600)) == -1) {
                warn("%s", to);
                (void)close(from_fd);
                return (1);
        }

        if (fchown(to_fd, sbp->st_uid, sbp->st_gid)) {
                serrno = errno;
                badchown = 1;
        }
        (void) fchmod(to_fd, sbp->st_mode & ~(S_ISUID|S_ISGID));

        while ((nread = read(from_fd, bp, blen)) > 0)
                if (write(to_fd, bp, nread) != nread) {
                        warn("%s", to);
                        goto err;
                }
        if (nread == -1) {
                warn("%s", from);
err:            if (unlink(to))
                        warn("%s: remove", to);
                (void)close(from_fd);
                (void)close(to_fd);
                return (1);
        }
        (void)close(from_fd);

        if (badchown) {
                if ((sbp->st_mode & (S_ISUID|S_ISGID)))  {
                        warnc(serrno,
                            "%s: set owner/group; not setting setuid/setgid",
                            to);
                        sbp->st_mode &= ~(S_ISUID|S_ISGID);
                } else if (!fflg)
                        warnc(serrno, "%s: set owner/group", to);
        }
        if (fchmod(to_fd, sbp->st_mode))
                warn("%s: set mode", 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.)
         */
        errno = 0;
        if (fchflags(to_fd, sbp->st_flags))
                if (errno != EOPNOTSUPP || sbp->st_flags != 0)
                        warn("%s: set flags", to);

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

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

        if (unlink(from)) {
                warn("%s: remove", from);
                return (1);
        }

        if (vflg)
                (void)fprintf(stdout, "%s -> %s\n", from, to);

        return (0);
}

int
mvcopy(char *from, char *to)
{
        char *argv[3];

        argv[0] = from;
        argv[1] = to;
        argv[2] = NULL;
        if (cpmain(2, argv)) {
                warn("cp failed");
                _exit(1);
        }

        argv[0] = from;
        argv[1] = NULL;
        if (rmmain(1, argv)) {
                warn("rm failed");
                _exit(1);
        }

        /*
         * XXX
         * The external cpmain(), rmmain() approach (to avoid
         * fork+exec) hides some of the details on what was moved.
         * This can be improved upon during a refactor.
         */
        if (vflg)
                (void)fprintf(stdout, "%s -> %s\n", from, to);

        return (0);
}

void
usage(void)
{
        (void)fprintf(stderr, "usage: %s [-fiv] source target\n", __progname);
        (void)fprintf(stderr, "       %s [-fiv] source ... directory\n",
            __progname);
        exit(1);
}