/*      $OpenBSD: cp.c,v 1.11 2024/10/14 08:26:48 jsg Exp $     */
/*      $NetBSD: cp.c,v 1.14 1995/09/07 06:14:51 jtc Exp $      */
/*      $NetBSD: utils.c,v 1.6 1997/02/26 14:40:51 cgd Exp $    */

/*
 * Copyright (c) 1988, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * David Hitz of Auspex Systems Inc.
 *
 * 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.
 */

/*
 * Cp copies source files to target files.
 *
 * The global PATH_T structure "to" always contains the path to the
 * current target file.  Since fts(3) does not change directories,
 * this path can be either absolute or dot-relative.
 *
 * The basic algorithm is to initialize "to" and use fts(3) to traverse
 * the file hierarchy rooted in the argument list.  A trivial case is the
 * case of 'cp file1 file2'.  The more interesting case is the case of
 * 'cp file1 file2 ... fileN dir' where the hierarchy is traversed and the
 * path (relative to the root of the traversal) is appended to dir (stored
 * in "to") to form the final target path.
 */

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

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

#define fts_dne(_x)     (_x->fts_pointer != NULL)

typedef struct {
        char *p_end;                    /* pointer to NULL at end of path */
        char *target_end;               /* pointer to end of target base */
        char p_path[PATH_MAX];          /* pointer to the start of a path */
} PATH_T;

static PATH_T to = { to.p_path, "" };

static int     copy_fifo(struct stat *, int);
static int     copy_file(FTSENT *, int);
static int     copy_link(FTSENT *, int);
static int     copy_special(struct stat *, int);
static int     setfile(struct stat *, int);


extern char *__progname;

static uid_t myuid;
static int fflag, iflag;
static mode_t myumask;

enum op { FILE_TO_FILE, FILE_TO_DIR, DIR_TO_DNE };

static int copy(char *[], enum op, int);
static char *find_last_component(char *);

static void __dead
usage(void)
{
        (void)fprintf(stderr,
            "usage: %s [-fip] [-R [-H | -L | -P]] source target\n", __progname);
        (void)fprintf(stderr,
            "       %s [-fip] [-R [-H | -L | -P]] source ... directory\n",
            __progname);
        exit(1);
}

int
cpmain(int argc, char *argv[])
{
        struct stat to_stat, tmp_stat;
        enum op type;
        int fts_options, r;
        char *target;

        fts_options = FTS_NOCHDIR | FTS_PHYSICAL;

        myuid = getuid();

        /* Copy the umask for explicit mode setting. */
        myumask = umask(0);
        (void)umask(myumask);

        /* Save the target base in "to". */
        target = argv[--argc];
        if (strlcpy(to.p_path, target, sizeof to.p_path) >= sizeof(to.p_path))
                errx(1, "%s: name too long", target);
        to.p_end = to.p_path + strlen(to.p_path);
        if (to.p_path == to.p_end) {
                *to.p_end++ = '.';
                *to.p_end = '\0';
        }
        to.target_end = to.p_end;

        /* Set end of argument list for fts(3). */
        argv[argc] = NULL;

        /*
         * Cp has two distinct cases:
         *
         * cp [-R] source target
         * cp [-R] source1 ... sourceN directory
         *
         * In both cases, source can be either a file or a directory.
         *
         * In (1), the target becomes a copy of the source. That is, if the
         * source is a file, the target will be a file, and likewise for
         * directories.
         *
         * In (2), the real target is not directory, but "directory/source".
         */
        r = stat(to.p_path, &to_stat);
        if (r == -1 && errno != ENOENT)
                err(1, "%s", to.p_path);
        if (r == -1 || !S_ISDIR(to_stat.st_mode)) {
                /*
                 * Case (1).  Target is not a directory.
                 */
                if (argc > 1)
                        usage();
                /*
                 * Need to detect the case:
                 *      cp -R dir foo
                 * Where dir is a directory and foo does not exist, where
                 * we want pathname concatenations turned on but not for
                 * the initial mkdir().
                 */
                if (r == -1) {
                        lstat(*argv, &tmp_stat);

                        if (S_ISDIR(tmp_stat.st_mode))
                                type = DIR_TO_DNE;
                        else
                                type = FILE_TO_FILE;
                } else
                        type = FILE_TO_FILE;
        } else {
                /*
                 * Case (2).  Target is a directory.
                 */
                type = FILE_TO_DIR;
        }

        return (copy(argv, type, fts_options));
}

static char *
find_last_component(char *path)
{
        char *p;

        if ((p = strrchr(path, '/')) == NULL)
                p = path;
        else {
                /* Special case foo/ */
                if (!*(p+1)) {
                        while ((p >= path) && *p == '/')
                                p--;

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

                p++;
        }

        return (p);
}

static int
copy(char *argv[], enum op type, int fts_options)
{
        struct stat to_stat;
        FTS *ftsp;
        FTSENT *curr;
        int base, nlen, rval;
        char *p, *target_mid;
        base = 0;

        if ((ftsp = fts_open(argv, fts_options, NULL)) == NULL)
                err(1, NULL);
        for (rval = 0; (curr = fts_read(ftsp)) != NULL;) {
                switch (curr->fts_info) {
                case FTS_NS:
                case FTS_DNR:
                case FTS_ERR:
                        warnx("%s: %s",
                            curr->fts_path, strerror(curr->fts_errno));
                        rval = 1;
                        continue;
                case FTS_DC:
                        warnx("%s: directory causes a cycle", curr->fts_path);
                        rval = 1;
                        continue;
                }

                /*
                 * If we are in case (2) or (3) above, we need to append the
                 * source name to the target name.
                 */
                if (type != FILE_TO_FILE) {
                        /*
                         * Need to remember the roots of traversals to create
                         * correct pathnames.  If there's a directory being
                         * copied to a non-existent directory, e.g.
                         *      cp -R a/dir noexist
                         * the resulting path name should be noexist/foo, not
                         * noexist/dir/foo (where foo is a file in dir), which
                         * is the case where the target exists.
                         *
                         * Also, check for "..".  This is for correct path
                         * concatenation for paths ending in "..", e.g.
                         *      cp -R .. /tmp
                         * Paths ending in ".." are changed to ".".  This is
                         * tricky, but seems the easiest way to fix the problem.
                         *
                         * XXX
                         * Since the first level MUST be FTS_ROOTLEVEL, base
                         * is always initialized.
                         */
                        if (curr->fts_level == FTS_ROOTLEVEL) {
                                if (type != DIR_TO_DNE) {
                                        p = find_last_component(curr->fts_path);
                                        base = p - curr->fts_path;
                                        
                                        if (!strcmp(&curr->fts_path[base],
                                            ".."))
                                                base += 1;
                                } else
                                        base = curr->fts_pathlen;
                        }

                        p = &curr->fts_path[base];
                        nlen = curr->fts_pathlen - base;
                        target_mid = to.target_end;
                        if (*p != '/' && target_mid[-1] != '/')
                                *target_mid++ = '/';
                        *target_mid = '\0';
                        if (target_mid - to.p_path + nlen >= PATH_MAX) {
                                warnx("%s%s: name too long (not copied)",
                                    to.p_path, p);
                                rval = 1;
                                continue;
                        }
                        (void)strncat(target_mid, p, nlen);
                        to.p_end = target_mid + nlen;
                        *to.p_end = '\0';
                }

                /* Not an error but need to remember it happened */
                if (stat(to.p_path, &to_stat) == -1) {
                        if (curr->fts_info == FTS_DP)
                                continue;
                        /*
                         * We use fts_pointer as a boolean to indicate that
                         * we created this directory ourselves.  We'll use
                         * this later on via the fts_dne macro to decide
                         * whether or not to set the directory mode during
                         * the post-order pass.
                         */
                        curr->fts_pointer = (void *)1;
                } else {
                        /*
                         * Set directory mode/user/times on the post-order
                         * pass.  We can't do this earlier because the mode
                         * may not allow us write permission.  Furthermore,
                         * if we set the times during the pre-order pass,
                         * they will get changed later when the directory
                         * is populated.
                         */
                        if (curr->fts_info == FTS_DP) {
                                if (!S_ISDIR(to_stat.st_mode))
                                        continue;
                                /*
                                 * If not -p and directory didn't exist, set
                                 * it to be the same as the from directory,
                                 * unmodified by the umask; arguably wrong,
                                 * but it's been that way forever.
                                 */
                                if (setfile(curr->fts_statp, -1))
                                        rval = 1;
                                else if (fts_dne(curr))
                                        (void)chmod(to.p_path,
                                            curr->fts_statp->st_mode);
                                continue;
                        }
                        if (to_stat.st_dev == curr->fts_statp->st_dev &&
                            to_stat.st_ino == curr->fts_statp->st_ino) {
                                warnx("%s and %s are identical (not copied).",
                                    to.p_path, curr->fts_path);
                                rval = 1;
                                if (S_ISDIR(curr->fts_statp->st_mode))
                                        (void)fts_set(ftsp, curr, FTS_SKIP);
                                continue;
                        }
                        if (!S_ISDIR(curr->fts_statp->st_mode) &&
                            S_ISDIR(to_stat.st_mode)) {
                warnx("cannot overwrite directory %s with non-directory %s",
                                    to.p_path, curr->fts_path);
                                rval = 1;
                                continue;
                        }
                }

                switch (curr->fts_statp->st_mode & S_IFMT) {
                case S_IFLNK:
                        if (copy_link(curr, !fts_dne(curr)))
                                rval = 1;
                        break;
                case S_IFDIR:
                        /*
                         * If the directory doesn't exist, create the new
                         * one with the from file mode plus owner RWX bits,
                         * modified by the umask.  Trade-off between being
                         * able to write the directory (if from directory is
                         * 555) and not causing a permissions race.  If the
                         * umask blocks owner writes, we fail..
                         */
                        if (fts_dne(curr)) {
                                if (mkdir(to.p_path,
                                    curr->fts_statp->st_mode | S_IRWXU) == -1)
                                        err(1, "%s", to.p_path);
                        } else if (!S_ISDIR(to_stat.st_mode))
                                errc(1, ENOTDIR, "%s", to.p_path);
                        break;
                case S_IFBLK:
                case S_IFCHR:
                                if (copy_special(curr->fts_statp, !fts_dne(curr)))
                                        rval = 1;
                        break;
                case S_IFIFO:
                                if (copy_fifo(curr->fts_statp, !fts_dne(curr)))
                                        rval = 1;
                        break;
                case S_IFSOCK:
                        warnc(EOPNOTSUPP, "%s", curr->fts_path);
                        break;
                default:
                        if (copy_file(curr, fts_dne(curr)))
                                rval = 1;
                        break;
                }
        }
        if (errno)
                err(1, "fts_read");
        (void)fts_close(ftsp);
        return (rval);
}

#define _MAXBSIZE       (64 * 1024)

static int
copy_file(FTSENT *entp, int dne)
{
        static char *buf;
        static char *zeroes;
        struct stat *fs;
        int ch, checkch, from_fd, rcount, rval, to_fd, wcount;
        const size_t buflen = _MAXBSIZE;
#ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED
        char *p;
#endif

        if (!buf) {
                buf = malloc(buflen);
                if (!buf)
                        err(1, "malloc");
        }
        if (!zeroes) {
                zeroes = calloc(1, buflen);
                if (!zeroes)
                        err(1, "calloc");
        }

        if ((from_fd = open(entp->fts_path, O_RDONLY)) == -1) {
                warn("%s", entp->fts_path);
                return (1);
        }

        fs = entp->fts_statp;

        /*
         * In -f (force) mode, we always unlink the destination first
         * if it exists.  Note that -i and -f are mutually exclusive.
         */
        if (!dne && fflag)
                (void)unlink(to.p_path);

        /*
         * If the file exists and we're interactive, verify with the user.
         * If the file DNE, set the mode to be the from file, minus setuid
         * bits, modified by the umask; arguably wrong, but it makes copying
         * executables work right and it's been that way forever.  (The
         * other choice is 666 or'ed with the execute bits on the from file
         * modified by the umask.)
         */
        if (!dne && !fflag) {
                if (iflag) {
                        (void)fprintf(stderr, "overwrite %s? ", to.p_path);
                        checkch = ch = getchar();
                        while (ch != '\n' && ch != EOF)
                                ch = getchar();
                        if (checkch != 'y' && checkch != 'Y') {
                                (void)close(from_fd);
                                return (0);
                        }
                }
                to_fd = open(to.p_path, O_WRONLY | O_TRUNC);
        } else
                to_fd = open(to.p_path, O_WRONLY | O_TRUNC | O_CREAT,
                    fs->st_mode & ~(S_ISTXT | S_ISUID | S_ISGID));

        if (to_fd == -1) {
                warn("%s", to.p_path);
                (void)close(from_fd);
                return (1);
        }

        rval = 0;

        /*
         * Mmap and write if less than 8M (the limit is so we don't totally
         * trash memory on big files.  This is really a minor hack, but it
         * wins some CPU back.
         */
#ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED
        /* XXX broken for 0-size mmap */
        if (fs->st_size <= 8 * 1048576) {
                if ((p = mmap(NULL, (size_t)fs->st_size, PROT_READ,
                    MAP_FILE|MAP_SHARED, from_fd, (off_t)0)) == MAP_FAILED) {
                        warn("mmap: %s", entp->fts_path);
                        rval = 1;
                } else {
                        madvise(p, fs->st_size, MADV_SEQUENTIAL);
                        if (write(to_fd, p, fs->st_size) != fs->st_size) {
                                warn("%s", to.p_path);
                                rval = 1;
                        }
                        /* Some systems don't unmap on close(2). */
                        if (munmap(p, fs->st_size) == -1) {
                                warn("%s", entp->fts_path);
                                rval = 1;
                        }
                }
        } else
#endif
        {
                int skipholes = 0;
                struct stat tosb;
                if (!fstat(to_fd, &tosb) && S_ISREG(tosb.st_mode))
                        skipholes = 1;
                while ((rcount = read(from_fd, buf, buflen)) > 0) {
                        if (skipholes && memcmp(buf, zeroes, rcount) == 0)
                                wcount = lseek(to_fd, rcount, SEEK_CUR) == -1 ? -1 : rcount;
                        else
                                wcount = write(to_fd, buf, rcount);
                        if (rcount != wcount || wcount == -1) {
                                warn("%s", to.p_path);
                                rval = 1;
                                break;
                        }
                }
                if (skipholes && rcount >= 0)
                        rcount = ftruncate(to_fd, lseek(to_fd, 0, SEEK_CUR));
                if (rcount == -1) {
                        warn("%s", entp->fts_path);
                        rval = 1;
                }
        }

        if (rval == 1) {
                (void)close(from_fd);
                (void)close(to_fd);
                return (1);
        }

        if (setfile(fs, to_fd))
                rval = 1;
        (void)close(from_fd);
        if (close(to_fd)) {
                warn("%s", to.p_path);
                rval = 1;
        }
        return (rval);
}

static int
copy_link(FTSENT *p, int exists)
{
        int len;
        char linkname[PATH_MAX];

        if ((len = readlink(p->fts_path, linkname, sizeof(linkname)-1)) == -1) {
                warn("readlink: %s", p->fts_path);
                return (1);
        }
        linkname[len] = '\0';
        if (exists && unlink(to.p_path)) {
                warn("unlink: %s", to.p_path);
                return (1);
        }
        if (symlink(linkname, to.p_path)) {
                warn("symlink: %s", linkname);
                return (1);
        }
        return (setfile(p->fts_statp, -1));
}

static int
copy_fifo(struct stat *from_stat, int exists)
{
        if (exists && unlink(to.p_path)) {
                warn("unlink: %s", to.p_path);
                return (1);
        }
        if (mkfifo(to.p_path, from_stat->st_mode)) {
                warn("mkfifo: %s", to.p_path);
                return (1);
        }
        return (setfile(from_stat, -1));
}

static int
copy_special(struct stat *from_stat, int exists)
{
        if (exists && unlink(to.p_path)) {
                warn("unlink: %s", to.p_path);
                return (1);
        }
        if (mknod(to.p_path, from_stat->st_mode, from_stat->st_rdev)) {
                warn("mknod: %s", to.p_path);
                return (1);
        }
        return (setfile(from_stat, -1));
}


static int
setfile(struct stat *fs, int fd)
{
        struct timespec ts[2];
        int rval;

        rval = 0;
        fs->st_mode &= S_ISTXT | S_ISUID | S_ISGID | S_IRWXU | S_IRWXG | S_IRWXO;

        ts[0] = fs->st_atim;
        ts[1] = fs->st_mtim;
        if (fd >= 0 ? futimens(fd, ts) :
            utimensat(AT_FDCWD, to.p_path, ts, AT_SYMLINK_NOFOLLOW)) {
                warn("update times: %s", to.p_path);
                rval = 1;
        }
        /*
         * Changing the ownership probably won't succeed, unless we're root
         * or POSIX_CHOWN_RESTRICTED is not set.  Set uid/gid before setting
         * the mode; current BSD behavior is to remove all setuid bits on
         * chown.  If chown fails, lose setuid/setgid bits.
         */
        if (fd >= 0 ? fchown(fd, fs->st_uid, fs->st_gid) :
            lchown(to.p_path, fs->st_uid, fs->st_gid)) {
                if (errno != EPERM) {
                        warn("chown: %s", to.p_path);
                        rval = 1;
                }
                fs->st_mode &= ~(S_ISTXT | S_ISUID | S_ISGID);
        }
        if (fd >= 0 ? fchmod(fd, fs->st_mode) :
            fchmodat(AT_FDCWD, to.p_path, fs->st_mode, AT_SYMLINK_NOFOLLOW)) {
                warn("chmod: %s", to.p_path);
                rval = 1;
        }

        /*
         * 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 (fd >= 0 ? fchflags(fd, fs->st_flags) :
            chflagsat(AT_FDCWD, to.p_path, fs->st_flags, AT_SYMLINK_NOFOLLOW))
                if (errno != EOPNOTSUPP || fs->st_flags != 0) {
                        warn("chflags: %s", to.p_path);
                        rval = 1;
                }
        return (rval);
}