/*-
 * 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 <err.h>
#include <errno.h>
#include <fts.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "extern.h"

#define STRIP_TRAILING_SLASH(p) {                                       \
        while ((p).p_end > (p).p_path + 1 && (p).p_end[-1] == '/')      \
                *--(p).p_end = 0;                                       \
}

#if defined(__FreeBSD__) || defined(__DragonFly__)
#define FTS_CONST const
#else
#define FTS_CONST
#endif

static char emptystring[] = "";

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

int fflag, iflag, lflag, nflag, pflag, vflag;
static int Rflag, rflag;
volatile sig_atomic_t info;

enum op { FILE_TO_FILE, FILE_TO_DIR, DIR_TO_DNE };

static int copy(char *[], enum op, int);
static int mastercmp (const FTSENT *FTS_CONST *, const FTSENT *FTS_CONST *);
#ifdef SIGINFO
static void siginfo (int);
#endif

int
main(int argc, char *argv[])
{
        struct stat to_stat, tmp_stat;
        enum op type;
        int Hflag, Lflag, Pflag, ch, fts_options, r, have_trailing_slash;
        char *target;

        fts_options = FTS_NOCHDIR | FTS_PHYSICAL;
        Hflag = Lflag = Pflag = 0;
        while ((ch = getopt(argc, argv, "HLPRafilnprvx")) != -1)
                switch (ch) {
                case 'H':
                        Hflag = 1;
                        Lflag = Pflag = 0;
                        break;
                case 'L':
                        Lflag = 1;
                        Hflag = Pflag = 0;
                        break;
                case 'P':
                        Pflag = 1;
                        Hflag = Lflag = 0;
                        break;
                case 'R':
                        Rflag = 1;
                        break;
                case 'a':
                        Pflag = 1;
                        pflag = 1;
                        Rflag = 1;
                        Hflag = Lflag = 0;
                        break;
                case 'f':
                        fflag = 1;
                        iflag = nflag = 0;
                        break;
                case 'i':
                        iflag = 1;
                        fflag = nflag = 0;
                        break;
                case 'l':
                        lflag = 1;
                        break;
                case 'n':
                        nflag = 1;
                        fflag = iflag = 0;
                        break;
                case 'p':
                        pflag = 1;
                        break;
                case 'r':
                        rflag = Lflag = 1;
                        Hflag = Pflag = 0;
                        break;
                case 'v':
                        vflag = 1;
                        break;
                case 'x':
                        fts_options |= FTS_XDEV;
                        break;
                default:
                        usage();
                        break;
                }
        argc -= optind;
        argv += optind;

        if (argc < 2)
                usage();

        if (Rflag && rflag)
                errx(1, "the -R and -r options may not be specified together");
        if (rflag)
                Rflag = 1;
        if (Rflag) {
                if (Hflag)
                        fts_options |= FTS_COMFOLLOW;
                if (Lflag) {
                        fts_options &= ~FTS_PHYSICAL;
                        fts_options |= FTS_LOGICAL;
                }
        } else {
                fts_options &= ~FTS_PHYSICAL;
                fts_options |= FTS_LOGICAL | FTS_COMFOLLOW;
        }
#ifdef SIGINFO
        signal(SIGINFO, siginfo);
#endif

        /* 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;
        }
        have_trailing_slash = (to.p_end[-1] == '/');
        if (have_trailing_slash)
                STRIP_TRAILING_SLASH(to);
        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)
                        errx(1, "%s is not a directory", to.p_path);

                /*
                 * 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) {
                        if (Rflag && (Lflag || Hflag))
                                stat(*argv, &tmp_stat);
                        else
                                lstat(*argv, &tmp_stat);

                        if (S_ISDIR(tmp_stat.st_mode) && Rflag)
                                type = DIR_TO_DNE;
                        else
                                type = FILE_TO_FILE;
                } else
                        type = FILE_TO_FILE;
                
                if (have_trailing_slash && type == FILE_TO_FILE) {
                        if (r == -1)
                                errx(1, "directory %s does not exist",
                                     to.p_path);
                        else
                                errx(1, "%s is not a directory", to.p_path);
                }
        } else
                /*
                 * Case (2).  Target is a directory.
                 */
                type = FILE_TO_DIR;

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

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

        /*
         * Keep an inverted copy of the umask, for use in correcting
         * permissions on created directories when not using -p.
         */
        mask = ~umask(0777);
        umask(~mask);

        if ((ftsp = fts_open(argv, fts_options, mastercmp)) == NULL)
                err(1, "fts_open");
        for (badcp = rval = 0; (curr = fts_read(ftsp)) != NULL; badcp = 0) {
                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:                    /* Warn, continue. */
                        warnx("%s: directory causes a cycle", curr->fts_path);
                        rval = 1;
                        continue;
                default:
                        ;
                }

                /*
                 * 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 = strrchr(curr->fts_path, '/');
                                        base = (p == NULL) ? 0 :
                                            (int)(p - curr->fts_path + 1);

                                        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;
                        }
                        strncat(target_mid, p, nlen);
                        to.p_end = target_mid + nlen;
                        *to.p_end = 0;
                        STRIP_TRAILING_SLASH(to);
                }

                if (curr->fts_info == FTS_DP) {
                        /*
                         * We are nearly finished with this directory.  If we
                         * didn't actually copy it, or otherwise don't need to
                         * change its attributes, then we are done.
                         */
                        if (!curr->fts_number)
                                continue;
                        /*
                         * If -p is in effect, set all the attributes.
                         * Otherwise, set the correct permissions, limited
                         * by the umask.  Optimise by avoiding a chmod()
                         * if possible (which is usually the case if we
                         * made the directory).  Note that mkdir() does not
                         * honour setuid, setgid and sticky bits, but we
                         * normally want to preserve them on directories.
                         */
                        if (pflag) {
                                if (setfile(curr->fts_statp, -1))
                                    rval = 1;
                        } else {
                                mode = curr->fts_statp->st_mode;
                                if ((mode & (S_ISUID | S_ISGID | S_ISTXT)) ||
                                    ((mode | S_IRWXU) & mask) != (mode & mask))
                                        if (chmod(to.p_path, mode & mask) != 0){
                                                warn("chmod: %s", to.p_path);
                                                rval = 1;
                                        }
                        }
                        continue;
                }

                /* Not an error but need to remember it happened */
                if (stat(to.p_path, &to_stat) == -1)
                        dne = 1;
                else {
                        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))
                                        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;
                        }
                        dne = 0;
                }

                switch (curr->fts_statp->st_mode & S_IFMT) {
                case S_IFLNK:
                        /* Catch special case of a non-dangling symlink */
                        if ((fts_options & FTS_LOGICAL) ||
                            ((fts_options & FTS_COMFOLLOW) &&
                            curr->fts_level == 0)) {
                                if (copy_file(curr, dne))
                                        badcp = rval = 1;
                        } else {        
                                if (copy_link(curr, !dne))
                                        badcp = rval = 1;
                        }
                        break;
                case S_IFDIR:
                        if (!Rflag) {
                                warnx("%s is a directory (not copied).",
                                    curr->fts_path);
                                fts_set(ftsp, curr, FTS_SKIP);
                                badcp = rval = 1;
                                break;
                        }
                        /*
                         * 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 (dne) {
                                if (mkdir(to.p_path,
                                    curr->fts_statp->st_mode | S_IRWXU) < 0)
                                        err(1, "%s", to.p_path);
                        } else if (!S_ISDIR(to_stat.st_mode)) {
                                errno = ENOTDIR;
                                err(1, "%s", to.p_path);
                        }
                        /*
                         * Arrange to correct directory attributes later
                         * (in the post-order phase) if this is a new
                         * directory, or if the -p flag is in effect.
                         */
                        curr->fts_number = pflag || dne;
                        break;
                case S_IFBLK:
                case S_IFCHR:
                        if (Rflag) {
                                if (copy_special(curr->fts_statp, !dne))
                                        badcp = rval = 1;
                        } else {
                                if (copy_file(curr, dne))
                                        badcp = rval = 1;
                        }
                        break;
                case S_IFSOCK:
                        warnx("%s is a socket (not copied).",
                                    curr->fts_path);
                        break;
                case S_IFIFO:
                        if (Rflag) {
                                if (copy_fifo(curr->fts_statp, !dne))
                                        badcp = rval = 1;
                        } else {
                                if (copy_file(curr, dne))
                                        badcp = rval = 1;
                        }
                        break;
                default:
                        if (copy_file(curr, dne))
                                badcp = rval = 1;
                        break;
                }
                if (vflag && !badcp)
                        printf("%s -> %s\n", curr->fts_path, to.p_path);
        }
        if (errno)
                err(1, "fts_read");
        fts_close(ftsp);
        return (rval);
}

/*
 * mastercmp --
 *      The comparison function for the copy order.  The order is to copy
 *      non-directory files before directory files.  The reason for this
 *      is because files tend to be in the same cylinder group as their
 *      parent directory, whereas directories tend not to be.  Copying the
 *      files first reduces seeking.
 */
static int
mastercmp(const FTSENT *FTS_CONST *a, const FTSENT *FTS_CONST *b)
{
        int a_info, b_info;

        a_info = (*a)->fts_info;
        if (a_info == FTS_ERR || a_info == FTS_NS || a_info == FTS_DNR)
                return (0);
        b_info = (*b)->fts_info;
        if (b_info == FTS_ERR || b_info == FTS_NS || b_info == FTS_DNR)
                return (0);
        if (a_info == FTS_D)
                return (-1);
        if (b_info == FTS_D)
                return (1);
        return (0);
}

#ifdef SIGINFO
static void
siginfo(int sig __unused)
{
        info = 1;
}
#endif