/* mv -- move or rename files
   Copyright (C) 86, 89, 90, 91, 95, 96, 1997 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* Options:
   -f, --force		Assume a 'y' answer to all questions it would
			normally ask, and not ask the questions.

   -i, --interactive	Require confirmation from the user before
			performing any move that would destroy an
			existing file.

   -u, --update		Do not move a nondirectory that has an
			existing destination with the same or newer
			modification time.

   -v, --verbose		List the name of each file as it is moved, and
			the name it is moved to.

   -b, --backup
   -S, --suffix
   -V, --version-control
			Backup file creation.

   Written by Mike Parker and David MacKenzie */

#ifdef _AIX
 #pragma alloca
#endif

#include <config.h>
#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>

#include "system.h"
#include "path-concat.h"
#include "backupfile.h"
#include "error.h"

#ifdef HAVE_LCHOWN
# define chown(PATH, OWNER, GROUP) lchown(PATH, OWNER, GROUP)
#endif

char *base_name ();
enum backup_type get_version ();
int isdir ();
int yesno ();
int safe_read ();
int full_write ();
int euidaccess ();

/* The name this program was run with. */
char *program_name;

/* If nonzero, query the user before overwriting files. */
static int interactive;

/* If nonzero, do not query the user before overwriting unwritable
   files. */
static int override_mode;

/* If nonzero, do not move a nondirectory that has an existing destination
   with the same or newer modification time. */
static int update = 0;

/* If nonzero, list each file as it is moved. */
static int verbose;

/* If nonzero, stdin is a tty. */
static int stdin_tty;

/* If nonzero, display usage information and exit.  */
static int show_help;

/* If nonzero, print the version on standard output and exit.  */
static int show_version;

static struct option const long_options[] =
{
  {"backup", no_argument, NULL, 'b'},
  {"force", no_argument, NULL, 'f'},
  {"interactive", no_argument, NULL, 'i'},
  {"suffix", required_argument, NULL, 'S'},
  {"update", no_argument, &update, 1},
  {"verbose", no_argument, &verbose, 1},
  {"version-control", required_argument, NULL, 'V'},
  {"help", no_argument, &show_help, 1},
  {"version", no_argument, &show_version, 1},
  {NULL, 0, NULL, 0}
};

/* If PATH is an existing directory, return nonzero, else 0.  */

static int
is_real_dir (const char *path)
{
  struct stat stats;

  return lstat (path, &stats) == 0 && S_ISDIR (stats.st_mode);
}

/* Apply as many of the file attributes (the struct stat fields: st_atime,
   st_mtime, st_uid, st_gid, st_mode) of ATTR to FILE as possible.
   Return non-zero if any operation failed; return zero otherwise.  */

static int
apply_attributes (const char *file, const struct stat *attr)
{
  struct utimbuf tv;
  mode_t mode = attr->st_mode;
  int fail = 0;

  /* Try to apply the modtime and access time.  */
  tv.actime = attr->st_atime;
  tv.modtime = attr->st_mtime;
  if (utime (file, &tv))
    {
      error (0, errno, "%s: unable to restore file times", file);
      fail = 1;
    }

  /* chown would turn off set[ug]id bits for non-root, so do the
     chown before the chmod.  */

  /* Try to apply group ID and owner ID.  */
  if (chown (file, attr->st_uid, attr->st_gid))
    {
      error (0, errno, "%s: unable to restore owner and group IDs", file);

      /* If the owner and group cannot be preserved, then mask off
	 any setgid and setuid bits.  */
      mode &= (~(S_ISUID | S_ISGID));
      fail = 1;
    }

  /* Try to apply file mode.  */
  if (chmod (file, mode & 07777))
    {
      error (0, errno, "%s: unable to restore file mode", file);
      fail = 1;
    }

  return fail;
}

/* Copy regular file SOURCE onto file DEST.  SOURCE_STATS must be
   the result of calling lstat on SOURCE.
   Return 1 if an error occurred, 0 if successful. */

static int
copy_reg (const char *source, const char *dest, const struct stat *source_stats)
{
  int ifd;
  int ofd;
  char buf[1024 * 8];
  int len;			/* Number of bytes read into `buf'. */

  if (!S_ISREG (source_stats->st_mode))
    {
      error (0, 0,
	     _("cannot move `%s' across filesystems: Not a regular file"),
	     source);
      return 1;
    }

  if (unlink (dest) && errno != ENOENT)
    {
      error (0, errno, _("cannot remove `%s'"), dest);
      return 1;
    }

  ifd = open (source, O_RDONLY, 0);
  if (ifd < 0)
    {
      error (0, errno, "%s", source);
      return 1;
    }
  ofd = open (dest, O_WRONLY | O_CREAT | O_TRUNC, 0600);
  if (ofd < 0)
    {
      error (0, errno, "%s", dest);
      close (ifd);
      return 1;
    }

  while ((len = safe_read (ifd, buf, sizeof (buf))) > 0)
    {
      if (full_write (ofd, buf, len) < 0)
	{
	  error (0, errno, "%s", dest);
	  close (ifd);
	  close (ofd);
	  unlink (dest);
	  return 1;
	}
    }
  if (len < 0)
    {
      error (0, errno, "%s", source);
      close (ifd);
      close (ofd);
      unlink (dest);
      return 1;
    }

  if (close (ifd) < 0)
    {
      error (0, errno, "%s", source);
      close (ofd);
      return 1;
    }
  if (close (ofd) < 0)
    {
      error (0, errno, "%s", dest);
      return 1;
    }

  /* Try to apply the attributes of SOURCE to DEST.
     Each failure gets a diagnostic, but POSIX requires that failure
     to preserve attributes not change mv's exit status.  */
  apply_attributes (dest, source_stats);

  return 0;
}

/* Move SOURCE onto DEST.  Handles cross-filesystem moves.
   If SOURCE is a directory, DEST must not exist.
   Return 0 if successful, 1 if an error occurred.  */

static int
do_move (const char *source, const char *dest)
{
  char *dest_backup = NULL;
  struct stat source_stats;
  struct stat dest_stats;

  if (lstat (source, &source_stats) != 0)
    {
      error (0, errno, "%s", source);
      return 1;
    }

  if (lstat (dest, &dest_stats) == 0)
    {

      if (source_stats.st_dev == dest_stats.st_dev
	  && source_stats.st_ino == dest_stats.st_ino)
	{
	  error (0, 0, _("`%s' and `%s' are the same file"), source, dest);
	  return 1;
	}

      if (S_ISDIR (dest_stats.st_mode))
	{
	  error (0, 0, _("%s: cannot overwrite directory"), dest);
	  return 1;
	}

      if (!S_ISDIR (source_stats.st_mode) && update
	  && source_stats.st_mtime <= dest_stats.st_mtime)
	return 0;

      if (!override_mode && (interactive || stdin_tty)
	  && euidaccess (dest, W_OK))
	{
	  fprintf (stderr, _("%s: replace `%s', overriding mode %04o? "),
		   program_name, dest,
		   (unsigned int) (dest_stats.st_mode & 07777));
	  if (!yesno ())
	    return 0;
	}
      else if (interactive)
	{
	  fprintf (stderr, _("%s: replace `%s'? "), program_name, dest);
	  if (!yesno ())
	    return 0;
	}

      if (backup_type != none)
	{
	  char *tmp_backup = find_backup_file_name (dest);
	  if (tmp_backup == NULL)
	    error (1, 0, _("virtual memory exhausted"));
	  dest_backup = (char *) alloca (strlen (tmp_backup) + 1);
	  strcpy (dest_backup, tmp_backup);
	  free (tmp_backup);
	  if (rename (dest, dest_backup))
	    {
	      if (errno != ENOENT)
		{
		  error (0, errno, _("cannot backup `%s'"), dest);
		  return 1;
		}
	      else
		dest_backup = NULL;
	    }
	}
    }
  else if (errno != ENOENT)
    {
      error (0, errno, "%s", dest);
      return 1;
    }

  if (verbose)
    printf ("%s -> %s\n", source, dest);

  if (rename (source, dest) == 0)
    {
      return 0;
    }

  if (errno != EXDEV)
    {
      error (0, errno, _("cannot move `%s' to `%s'"), source, dest);
      goto un_backup;
    }

  /* rename failed on cross-filesystem link.  Copy the file instead. */

  if (copy_reg (source, dest, &source_stats))
    goto un_backup;

  if (unlink (source))
    {
      error (0, errno, _("cannot remove `%s'"), source);
      return 1;
    }

  return 0;

 un_backup:
  if (dest_backup)
    {
      if (rename (dest_backup, dest))
	error (0, errno, _("cannot un-backup `%s'"), dest);
    }
  return 1;
}

static int
strip_trailing_slashes_2 (char *path)
{
  char *end_p = path + strlen (path) - 1;
  char *slash = end_p;

  while (slash > path && *slash == '/')
    *slash-- = '\0';

  return slash < end_p;
}

/* Move file SOURCE onto DEST.  Handles the case when DEST is a directory.
   DEST_IS_DIR must be nonzero when DEST is a directory or a symlink to a
   directory and zero otherwise.
   Return 0 if successful, 1 if an error occurred.  */

static int
movefile (char *source, char *dest, int dest_is_dir)
{
  int dest_had_trailing_slash = strip_trailing_slashes_2 (dest);
  int fail;

  /* In addition to when DEST is a directory, if DEST has a trailing
     slash and neither SOURCE nor DEST is a directory, presume the target
     is DEST/`basename source`.  This converts `mv x y/' to `mv x y/x'.
     This change means that the command `mv any file/' will now fail
     rather than performing the move.  The case when SOURCE is a
     directory and DEST is not is properly diagnosed by do_move.  */

  if (dest_is_dir || (dest_had_trailing_slash && !is_real_dir (source)))
    {
      /* DEST is a directory; build full target filename. */
      char *src_basename;
      char *new_dest;

      /* Remove trailing slashes before taking base_name.
	 Otherwise, base_name ("a/") returns "".  */
      strip_trailing_slashes_2 (source);

      src_basename = base_name (source);
      new_dest = path_concat (dest, src_basename, NULL);
      if (new_dest == NULL)
	error (1, 0, _("virtual memory exhausted"));
      fail = do_move (source, new_dest);
      free (new_dest);
    }
  else
    {
      fail = do_move (source, dest);
    }

  return fail;
}

static void
usage (int status)
{
  if (status != 0)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
	     program_name);
  else
    {
      printf (_("\
Usage: %s [OPTION]... SOURCE DEST\n\
  or:  %s [OPTION]... SOURCE... DIRECTORY\n\
"),
	      program_name, program_name);
      printf (_("\
Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY.\n\
\n\
  -b, --backup                 make backup before removal\n\
  -f, --force                  remove existing destinations, never prompt\n\
  -i, --interactive            prompt before overwrite\n\
  -S, --suffix=SUFFIX          override the usual backup suffix\n\
  -u, --update                 move only older or brand new files\n\
  -v, --verbose                explain what is being done\n\
  -V, --version-control=WORD   override the usual version control\n\
      --help                   display this help and exit\n\
      --version                output version information and exit\n\
\n\
"));
      printf (_("\
The backup suffix is ~, unless set with SIMPLE_BACKUP_SUFFIX.  The\n\
version control may be set with VERSION_CONTROL, values are:\n\
\n\
  t, numbered     make numbered backups\n\
  nil, existing   numbered if numbered backups exist, simple otherwise\n\
  never, simple   always make simple backups\n\
"));
      puts (_("\nReport bugs to <fileutils-bugs@gnu.org>."));
    }
  exit (status);
}

int
main (int argc, char **argv)
{
  int c;
  int errors;
  int make_backups = 0;
  int dest_is_dir;
  char *version;

  program_name = argv[0];
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  version = getenv ("SIMPLE_BACKUP_SUFFIX");
  if (version)
    simple_backup_suffix = version;
  version = getenv ("VERSION_CONTROL");

  interactive = override_mode = verbose = update = 0;
  errors = 0;

  while ((c = getopt_long (argc, argv, "bfiuvS:V:", long_options, NULL)) != -1)
    {
      switch (c)
	{
	case 0:
	  break;
	case 'b':
	  make_backups = 1;
	  break;
	case 'f':
	  interactive = 0;
	  override_mode = 1;
	  break;
	case 'i':
	  interactive = 1;
	  override_mode = 0;
	  break;
	case 'u':
	  update = 1;
	  break;
	case 'v':
	  verbose = 1;
	  break;
	case 'S':
	  simple_backup_suffix = optarg;
	  break;
	case 'V':
	  version = optarg;
	  break;
	default:
	  usage (1);
	}
    }

  if (show_version)
    {
      printf ("mv (%s) %s\n", GNU_PACKAGE, VERSION);
      exit (0);
    }

  if (show_help)
    usage (0);

  if (argc < optind + 2)
    {
      error (0, 0, "%s", (argc == optind
			  ? _("missing file arguments")
			  : _("missing file argument")));
      usage (1);
    }

  if (make_backups)
    backup_type = get_version (version);

  stdin_tty = isatty (STDIN_FILENO);
  dest_is_dir = isdir (argv[argc - 1]);

  if (argc > optind + 2 && !dest_is_dir)
    error (1, 0,
	   _("when moving multiple files, last argument must be a directory"));

  /* Move each arg but the last onto the last. */
  for (; optind < argc - 1; ++optind)
    errors |= movefile (argv[optind], argv[argc - 1], dest_is_dir);

  exit (errors);
}