coreutils/src/cp.c

/* cp.c  -- file copying (main routines)
   Copyright (C) 89, 90, 91, 95, 1996 Free Software Foundation.

   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.

   Written by Torbjorn Granlund, David MacKenzie, and Jim Meyering. */

#ifdef _AIX
 #pragma alloca
#endif

#include <config.h>
#include <stdio.h>

#define NDEBUG
#include <assert.h>

#include <getopt.h>
#include "cp.h"
#include "backupfile.h"
#include "argmatch.h"

#ifndef _POSIX_VERSION
uid_t geteuid ();
#endif

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

/* Used by do_copy, make_path_private, and re_protect
   to keep a list of leading directories whose protections
   need to be fixed after copying. */
struct dir_attr
{
  int is_new_dir;
  int slash_offset;
  struct dir_attr *next;
};

/* Control creation of sparse files (files with holes).  */
enum Sparse_type
{
  /* Never create holes in DEST.  */
  SPARSE_NEVER,

  /* This is the default.  Use a crude (and sometimes inaccurate)
     heuristic to determine if SOURCE has holes.  If so, try to create
     holes in DEST.  */
  SPARSE_AUTO,

  /* For every sufficiently long sequence of bytes in SOURCE, try to
     create a corresponding hole in DEST.  There is a performance penalty
     here because CP has to search for holes in SRC.  But if the holes are
     big enough, that penalty can be offset by the decrease in the amount
     of data written to disk.   */
  SPARSE_ALWAYS
};

int stat ();
int lstat ();

char *dirname ();
char *xstrdup ();
enum backup_type get_version ();
int euidaccess ();
int full_write ();

static int do_copy __P ((int argc, char **argv));
static int copy __P ((const char *src_path, const char *dst_path, int new_dst,
		      dev_t device, struct dir_list *ancestors));
static int copy_dir __P ((const char *src_path_in, const char *dst_path_in,
			  int new_dst, const struct stat *src_sb,
			  struct dir_list *ancestors));
static int make_path_private __P ((const char *const_dirpath, int src_offset,
				   int mode, const char *verbose_fmt_string,
				   struct dir_attr **attr_list, int *new_dst));
static int copy_reg __P ((const char *src_path, const char *dst_path));
static int re_protect __P ((const char *const_dst_path, int src_offset,
			    struct dir_attr *attr_list));

/* Initial number of entries in each hash table entry's table of inodes.  */
#define INITIAL_HASH_MODULE 100

/* Initial number of entries in the inode hash table.  */
#define INITIAL_ENTRY_TAB_SIZE 70

/* The invocation name of this program.  */
char *program_name;

/* A pointer to either lstat or stat, depending on
   whether dereferencing of symlinks is done.  */
static int (*xstat) ();

/* If nonzero, copy all files except (directories and, if not dereferencing
   them, symbolic links,) as if they were regular files. */
static int flag_copy_as_regular = 1;

/* If nonzero, dereference symbolic links (copy the files they point to). */
static int flag_dereference = 1;

/* If nonzero, remove existing destination nondirectories. */
static int flag_force = 0;

/* If nonzero, create hard links instead of copying files.
   Create destination directories as usual. */
static int flag_hard_link = 0;

/* If nonzero, query before overwriting existing destinations
   with regular files. */
static int flag_interactive = 0;

/* If nonzero, the command "cp x/e_file e_dir" uses "e_dir/x/e_file"
   as its destination instead of the usual "e_dir/e_file." */
static int flag_path = 0;

/* If nonzero, give the copies the original files' permissions,
   ownership, and timestamps. */
static int flag_preserve = 0;

/* If nonzero, copy directories recursively and copy special files
   as themselves rather than copying their contents. */
static int flag_recursive = 0;

/* If nonzero, create symbolic links instead of copying files.
   Create destination directories as usual. */
static int flag_symbolic_link = 0;

/* If nonzero, when copying recursively, skip any subdirectories that are
   on different filesystems from the one we started on. */
static int flag_one_file_system = 0;

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

/* If nonzero, display the names of the files before copying them. */
static int flag_verbose = 0;

static char const *const sparse_type_string[] =
{
  "never", "auto", "always", 0
};

static enum Sparse_type const sparse_type[] =
{
  SPARSE_NEVER, SPARSE_AUTO, SPARSE_ALWAYS
};

/* Control creation of sparse files.  */
static int flag_sparse = SPARSE_AUTO;

/* The error code to return to the system. */
static int exit_status = 0;

/* The bits to preserve in created files' modes. */
static int umask_kill;

/* This process's effective user ID.  */
static uid_t myeuid;

/* 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_opts[] =
{
  {"archive", no_argument, NULL, 'a'},
  {"backup", no_argument, NULL, 'b'},
  {"force", no_argument, NULL, 'f'},
  {"sparse", required_argument, NULL, 2},
  {"interactive", no_argument, NULL, 'i'},
  {"link", no_argument, NULL, 'l'},
  {"no-dereference", no_argument, &flag_dereference, 0},
  {"one-file-system", no_argument, &flag_one_file_system, 1},
  {"parents", no_argument, &flag_path, 1},
  {"path", no_argument, &flag_path, 1},
  {"preserve", no_argument, &flag_preserve, 1},
  {"recursive", no_argument, NULL, 'R'},
  {"suffix", required_argument, NULL, 'S'},
  {"symbolic-link", no_argument, NULL, 's'},
  {"update", no_argument, &flag_update, 1},
  {"verbose", no_argument, &flag_verbose, 1},
  {"version-control", required_argument, NULL, 'V'},
  {"help", no_argument, &show_help, 1},
  {"version", no_argument, &show_version, 1},
  {NULL, 0, NULL, 0}
};

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

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

  myeuid = geteuid ();

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

  /* Find out the current file creation mask, to knock the right bits
     when using chmod.  The creation mask is set to to be liberal, so
     that created directories can be written, even if it would not
     have been allowed with the mask this process was started with.  */

  umask_kill = 0777777 ^ umask (0);

  while ((c = getopt_long (argc, argv, "abdfilprsuvxPRS:V:", long_opts,
			   (int *) 0)) != EOF)
    {
      switch (c)
	{
	case 0:
	  break;

	case 2:
	  {
	    int i;

	    /* --sparse={never,auto,always}  */
	    i = argmatch (optarg, sparse_type_string);
	    if (i < 0)
	      {
		invalid_arg (_("sparse type"), optarg, i);
		usage (2, NULL);
	      }
	    flag_sparse = sparse_type[i];
	  }
	  break;

	case 'a':		/* Like -dpR. */
	  flag_dereference = 0;
	  flag_preserve = 1;
	  flag_recursive = 1;
	  flag_copy_as_regular = 0;
	  break;

	case 'b':
	  make_backups = 1;
	  break;

	case 'd':
	  flag_dereference = 0;
	  break;

	case 'f':
	  flag_force = 1;
	  flag_interactive = 0;
	  break;

	case 'i':
	  flag_force = 0;
	  flag_interactive = 1;
	  break;

	case 'l':
	  flag_hard_link = 1;
	  break;

	case 'p':
	  flag_preserve = 1;
	  break;

	case 'P':
	  flag_path = 1;
	  break;

	case 'r':
	  flag_recursive = 1;
	  flag_copy_as_regular = 1;
	  break;

	case 'R':
	  flag_recursive = 1;
	  flag_copy_as_regular = 0;
	  break;

	case 's':
#ifdef S_ISLNK
	  flag_symbolic_link = 1;
#else
	  error (1, 0, _("symbolic links are not supported on this system"));
#endif
	  break;

	case 'u':
	  flag_update = 1;
	  break;

	case 'v':
	  flag_verbose = 1;
	  break;

	case 'x':
	  flag_one_file_system = 1;
	  break;

	case 'S':
	  simple_backup_suffix = optarg;
	  break;

	case 'V':
	  version = optarg;
	  break;

	default:
	  usage (2, (char *) 0);
	}
    }

  if (show_version)
    {
      printf ("cp - %s\n", PACKAGE_VERSION);
      exit (0);
    }

  if (show_help)
    usage (0, NULL);

  if (flag_hard_link && flag_symbolic_link)
    usage (2, _("cannot make both hard and symbolic links"));

  if (make_backups)
    backup_type = get_version (version);

  if (flag_preserve == 1)
    umask_kill = 0777777;

  /* The key difference between -d (--no-dereference) and not is the version
     of `stat' to call.  */

  if (flag_dereference)
    xstat = stat;
  else
    xstat = lstat;

  /* Allocate space for remembering copied and created files.  */

  hash_init (INITIAL_HASH_MODULE, INITIAL_ENTRY_TAB_SIZE);

  exit_status |= do_copy (argc, argv);

  exit (exit_status);
}

/* Concatenate two pathname components, DIR and BASE, in newly-allocated
   storage and return the result.  Be careful that in the result they are
   separated by a slash.  That is, if DIR ends with a slash or if BASE
   begins with one, don't add a separating slash.  Otherwise, add one.  */

static char *
path_concat (const char *dir, const char *base)
{
  char *dir_end;
  char *p_concat;

  assert (strlen (dir) > 0);
  p_concat = xmalloc (strlen (dir) + strlen (base) + 2);
  dir_end = stpcpy (p_concat, dir);
  if (*(dir_end - 1) == '/')
    --dir_end;
  else if (*base == '/')
    ++base;
  stpcpy (stpcpy (dir_end, "/"), base);
  return p_concat;
}

/* Scan the arguments, and copy each by calling copy.
   Return 0 if successful, 1 if any errors occur. */

static int
do_copy (int argc, char **argv)
{
  char *dest;
  struct stat sb;
  int new_dst = 0;
  int ret = 0;

  if (optind >= argc)
    usage (2, _("missing file arguments"));
  if (optind >= argc - 1)
    usage (2, _("missing destination file"));

  dest = argv[argc - 1];

  if (lstat (dest, &sb))
    {
      if (errno != ENOENT)
	{
	  error (0, errno, "%s", dest);
	  return 1;
	}
      else
	new_dst = 1;
    }
  else
    {
      struct stat sbx;

      /* If `dest' is not a symlink to a nonexistent file, use
	 the results of stat instead of lstat, so we can copy files
	 into symlinks to directories. */
      if (stat (dest, &sbx) == 0)
	sb = sbx;
    }

  if (!new_dst && S_ISDIR (sb.st_mode))
    {
      /* cp file1...filen edir
	 Copy the files `file1' through `filen'
	 to the existing directory `edir'. */

      for (;;)
	{
	  char *arg;
	  char *ap;
	  char *dst_path;
	  int parent_exists = 1; /* True if dirname (dst_path) exists. */
	  struct dir_attr *attr_list;

	  arg = argv[optind];

	  strip_trailing_slashes (arg);

	  if (flag_path)
	    {
	      /* Append all of `arg' to `dest'.  */
	      dst_path = path_concat (dest, arg);

	      /* For --parents, we have to make sure that the directory
	         dirname (dst_path) exists.  We may have to create a few
	         leading directories. */
	      parent_exists = !make_path_private (dst_path,
						  strlen (dest) + 1, 0700,
						  (flag_verbose
						   ? "%s -> %s\n" : NULL),
						  &attr_list, &new_dst);
	    }
  	  else
  	    {
	      /* Append the last component of `arg' to `dest'.  */

	      ap = basename (arg);
	      /* For `cp -R source/.. dest', don't copy into `dest/..'. */
	      dst_path = (STREQ (ap, "..")
			  ? xstrdup (dest)
			  : path_concat (dest, ap));
	    }

	  if (!parent_exists)
	    {
	      /* make_path_private failed, so don't even attempt the copy. */
	      ret = 1;
  	    }
	  else
	    {
	      ret |= copy (arg, dst_path, new_dst, 0, (struct dir_list *) 0);
	      forget_all ();

	      if (flag_path)
		{
		  ret |= re_protect (dst_path, strlen (dest) + 1, attr_list);
		}
	    }

	  free (dst_path);
	  ++optind;
	  if (optind == argc - 1)
	    break;
	}
      return ret;
    }
  else if (argc - optind == 2)
    {
      char *new_dest;
      char *source;
      struct stat source_stats;

      if (flag_path)
	usage (2,
	       _("when preserving paths, last argument must be a directory"));

      source = argv[optind];

      /* When the force and backup options have been specified and
	 the source and destination are the same name for an existing
	 regular file, convert the user's command, e.g.,
	 `cp --force --backup foo foo' to `cp --force foo fooSUFFIX'
	 where SUFFIX is determined by any version control options used.  */

      if (flag_force
	  && backup_type != none
	  && STREQ (source, dest)
	  && !new_dst && S_ISREG (sb.st_mode))
	 {
	   backup_type = none;
	   new_dest = find_backup_file_name (dest);
	   if (new_dest == NULL)
	     error (1, 0, _("virtual memory exhausted"));
	 }

      /* When the destination is specified with a trailing slash and the
	 source exists but is not a directory, convert the user's command
	 `cp source dest/' to `cp source dest/basename(source)'.  */

      else if (dest[strlen (dest) - 1] == '/'
	  && lstat (source, &source_stats) == 0
	  && !S_ISDIR (source_stats.st_mode))
	{
	  char *source_base;
	  char *tmp_source;

	  tmp_source = (char *) alloca (strlen (source) + 1);
	  strcpy (tmp_source, source);
	  strip_trailing_slashes (tmp_source);
	  source_base = basename (tmp_source);

	  new_dest = (char *) alloca (strlen (dest) + 1 +
				      strlen (source_base) + 1);
	  stpcpy (stpcpy (stpcpy (new_dest, dest), "/"), source_base);
	}
      else
	{
	  new_dest = dest;
	}

      return copy (source, new_dest, new_dst, 0, (struct dir_list *) 0);
    }
  else
    usage (2,
	 _("when copying multiple files, last argument must be a directory"));
}

/* Copy the file SRC_PATH to the file DST_PATH.  The files may be of
   any type.  NEW_DST should be nonzero if the file DST_PATH cannot
   exist because its parent directory was just created; NEW_DST should
   be zero if DST_PATH might already exist.  DEVICE is the device
   number of the parent directory, or 0 if the parent of this file is
   not known.  ANCESTORS points to a linked, null terminated list of
   devices and inodes of parent directories of SRC_PATH.
   Return 0 if successful, 1 if an error occurs. */

static int
copy (const char *src_path, const char *dst_path, int new_dst, dev_t device,
      struct dir_list *ancestors)
{
  struct stat src_sb;
  struct stat dst_sb;
  int src_mode;
  int src_type;
  char *earlier_file;
  char *dst_backup = NULL;
  int fix_mode = 0;

  if ((*xstat) (src_path, &src_sb))
    {
      error (0, errno, "%s", src_path);
      return 1;
    }

  /* Are we crossing a file system boundary?  */
  if (flag_one_file_system && device != 0 && device != src_sb.st_dev)
    return 0;

  /* We wouldn't insert a node unless nlink > 1, except that we need to
     find created files so as to not copy infinitely if a directory is
     copied into itself.  */

  earlier_file = remember_copied (dst_path, src_sb.st_ino, src_sb.st_dev);

  /* Did we just create this file?  */

  if (earlier_file == &new_file)
    return 0;

  src_mode = src_sb.st_mode;
  src_type = src_sb.st_mode;

  if (S_ISDIR (src_type) && !flag_recursive)
    {
      error (0, 0, _("%s: omitting directory"), src_path);
      return 1;
    }

  if (!new_dst)
    {
      if ((*xstat) (dst_path, &dst_sb))
	{
	  if (errno != ENOENT)
	    {
	      error (0, errno, "%s", dst_path);
	      return 1;
	    }
	  else
	    new_dst = 1;
	}
      else
	{
	  /* The file exists already.  */

	  if (src_sb.st_ino == dst_sb.st_ino && src_sb.st_dev == dst_sb.st_dev)
	    {
	      if (flag_hard_link)
		return 0;

	      error (0, 0, _("`%s' and `%s' are the same file"),
		     src_path, dst_path);
	      return 1;
	    }

	  if (!S_ISDIR (src_type))
	    {
	      if (S_ISDIR (dst_sb.st_mode))
		{
		  error (0, 0,
		       _("%s: cannot overwrite directory with non-directory"),
			 dst_path);
		  return 1;
		}

	      if (flag_update && src_sb.st_mtime <= dst_sb.st_mtime)
		return 0;
	    }

	  if (S_ISREG (src_type) && !flag_force)
	    {
	      if (flag_interactive)
		{
		  if (euidaccess (dst_path, W_OK) != 0)
		    fprintf (stderr,
			     _("%s: overwrite `%s', overriding mode %04o? "),
			     program_name, dst_path,
			     (unsigned int) (dst_sb.st_mode & 07777));
		  else
		    fprintf (stderr, _("%s: overwrite `%s'? "),
			     program_name, dst_path);
		  if (!yesno ())
		    return 0;
		}
	    }

	  if (backup_type != none && !S_ISDIR (dst_sb.st_mode))
	    {
	      char *tmp_backup = find_backup_file_name (dst_path);
	      if (tmp_backup == NULL)
		error (1, 0, _("virtual memory exhausted"));

	      /* Detect (and fail) when creating the backup file would
		 destroy the source file.  Before, running the commands
		 cd /tmp; rm -f a a~; : > a; echo A > a~; cp -b -V simple a~ a
		 would leave two zero-length files: a and a~.  */
	      if (STREQ (tmp_backup, src_path))
		{
		  error (0, 0,
		   _("backing up `%s' would destroy source;  `%s' not copied"),
			 dst_path, src_path);
		  return 1;

		}
	      dst_backup = (char *) alloca (strlen (tmp_backup) + 1);
	      strcpy (dst_backup, tmp_backup);
	      free (tmp_backup);
	      if (rename (dst_path, dst_backup))
		{
		  if (errno != ENOENT)
		    {
		      error (0, errno, _("cannot backup `%s'"), dst_path);
		      return 1;
		    }
		  else
		    dst_backup = NULL;
		}
	      new_dst = 1;
	    }
	  else if (flag_force)
	    {
	      if (S_ISDIR (dst_sb.st_mode))
		{
		  /* Temporarily change mode to allow overwriting. */
		  if (euidaccess (dst_path, W_OK | X_OK) != 0)
		    {
		      if (chmod (dst_path, 0700))
			{
			  error (0, errno, "%s", dst_path);
			  return 1;
			}
		      else
			fix_mode = 1;
		    }
		}
	      else
		{
		  if (unlink (dst_path) && errno != ENOENT)
		    {
		      error (0, errno, _("cannot remove old link to `%s'"),
			     dst_path);
		      return 1;
		    }
		  new_dst = 1;
		}
	    }
	}
    }

  /* If the source is a directory, we don't always create the destination
     directory.  So --verbose should not announce anything until we're
     sure we'll create a directory. */
  if (flag_verbose && !S_ISDIR (src_type))
    printf ("%s -> %s\n", src_path, dst_path);

  /* Did we copy this inode somewhere else (in this command line argument)
     and therefore this is a second hard link to the inode?  */

  if (!flag_dereference && src_sb.st_nlink > 1 && earlier_file)
    {
      if (link (earlier_file, dst_path))
	{
	  error (0, errno, "%s", dst_path);
	  goto un_backup;
	}
      return 0;
    }

  if (S_ISDIR (src_type))
    {
      struct dir_list *dir;

      /* If this directory has been copied before during the
         recursion, there is a symbolic link to an ancestor
         directory of the symbolic link.  It is impossible to
         continue to copy this, unless we've got an infinite disk.  */

      if (is_ancestor (&src_sb, ancestors))
	{
	  error (0, 0, _("%s: cannot copy cyclic symbolic link"), src_path);
	  goto un_backup;
	}

      /* Insert the current directory in the list of parents.  */

      dir = (struct dir_list *) alloca (sizeof (struct dir_list));
      dir->parent = ancestors;
      dir->ino = src_sb.st_ino;
      dir->dev = src_sb.st_dev;

      if (new_dst || !S_ISDIR (dst_sb.st_mode))
	{
	  /* Create the new directory writable and searchable, so
             we can create new entries in it.  */

	  if (mkdir (dst_path, (src_mode & umask_kill) | 0700))
	    {
	      error (0, errno, _("cannot create directory `%s'"), dst_path);
	      goto un_backup;
	    }

	  /* Insert the created directory's inode and device
             numbers into the search structure, so that we can
             avoid copying it again.  */

	  if (remember_created (dst_path))
	    goto un_backup;

	  if (flag_verbose)
	    printf ("%s -> %s\n", src_path, dst_path);
	}

      /* Copy the contents of the directory.  */

      if (copy_dir (src_path, dst_path, new_dst, &src_sb, dir))
	return 1;
    }
#ifdef S_ISLNK
  else if (flag_symbolic_link)
    {
      if (*src_path == '/'
	  || (!strncmp (dst_path, "./", 2) && strchr (dst_path + 2, '/') == 0)
	  || strchr (dst_path, '/') == 0)
	{
	  if (symlink (src_path, dst_path))
	    {
	      error (0, errno, "%s", dst_path);
	      goto un_backup;
	    }
	  return 0;
	}
      else
	{
	  error (0, 0,
	   _("%s: can make relative symbolic links only in current directory"),
		 dst_path);
	  goto un_backup;
	}
    }
#endif
  else if (flag_hard_link)
    {
      if (link (src_path, dst_path))
	{
	  error (0, errno, _("cannot create link `%s'"), dst_path);
	  goto un_backup;
	}
      return 0;
    }
  else if (S_ISREG (src_type)
	   || (flag_copy_as_regular && !S_ISDIR (src_type)
#ifdef S_ISLNK
	       && !S_ISLNK (src_type)
#endif
	       ))
    {
      if (copy_reg (src_path, dst_path))
	goto un_backup;
    }
  else
#ifdef S_ISFIFO
  if (S_ISFIFO (src_type))
    {
      if (mkfifo (dst_path, src_mode & umask_kill))
	{
	  error (0, errno, _("cannot create fifo `%s'"), dst_path);
	  goto un_backup;
	}
    }
  else
#endif
    if (S_ISBLK (src_type) || S_ISCHR (src_type)
#ifdef S_ISSOCK
	|| S_ISSOCK (src_type)
#endif
	)
    {
      if (mknod (dst_path, src_mode & umask_kill, src_sb.st_rdev))
	{
	  error (0, errno, _("cannot create special file `%s'"), dst_path);
	  goto un_backup;
	}
    }
  else
#ifdef S_ISLNK
  if (S_ISLNK (src_type))
    {
      char *link_val;
      int link_size;

      link_val = (char *) alloca (PATH_MAX + 2);
      link_size = readlink (src_path, link_val, PATH_MAX + 1);
      if (link_size < 0)
	{
	  error (0, errno, _("cannot read symbolic link `%s'"), src_path);
	  goto un_backup;
	}
      link_val[link_size] = '\0';

      if (symlink (link_val, dst_path))
	{
	  error (0, errno, _("cannot create symbolic link `%s'"), dst_path);
	  goto un_backup;
	}
      return 0;
    }
  else
#endif
    {
      error (0, 0, _("%s: unknown file type"), src_path);
      goto un_backup;
    }

  /* Adjust the times (and if possible, ownership) for the copy.
     chown turns off set[ug]id bits for non-root,
     so do the chmod last.  */

  if (flag_preserve)
    {
      struct utimbuf utb;

      utb.actime = src_sb.st_atime;
      utb.modtime = src_sb.st_mtime;

      if (utime (dst_path, &utb))
	{
	  error (0, errno, "%s", dst_path);
	  return 1;
	}

      /* If non-root uses -p, it's ok if we can't preserve ownership.
	 But root probably wants to know, e.g. if NFS disallows it.  */
      if (chown (dst_path,
		 (myeuid == 0 ? src_sb.st_uid : myeuid),
		 src_sb.st_gid)
	  && (errno != EPERM || myeuid == 0))
	{
	  error (0, errno, "%s", dst_path);
	  return 1;
	}
    }

  if ((flag_preserve || new_dst)
      && (flag_copy_as_regular || S_ISREG (src_type) || S_ISDIR (src_type)))
    {
      if (chmod (dst_path, src_mode & umask_kill))
	{
	  error (0, errno, "%s", dst_path);
	  return 1;
	}
    }
  else if (fix_mode)
    {
      /* Reset the temporarily changed mode.  */
      if (chmod (dst_path, dst_sb.st_mode))
	{
	  error (0, errno, "%s", dst_path);
	  return 1;
	}
    }

  return 0;

un_backup:
  if (dst_backup)
    {
      if (rename (dst_backup, dst_path))
	error (0, errno, _("cannot un-backup `%s'"), dst_path);
    }
  return 1;
}

/* Ensure that the parent directory of CONST_DIRPATH exists, for
   the --parents option.

   SRC_OFFSET is the index in CONST_DIRPATH (which is a destination
   path) of the beginning of the source directory name.
   Create any leading directories that don't already exist,
   giving them permissions MODE.
   If VERBOSE_FMT_STRING is nonzero, use it as a printf format
   string for printing a message after successfully making a directory.
   The format should take two string arguments: the names of the
   source and destination directories.
   Creates a linked list of attributes of intermediate directories,
   *ATTR_LIST, for re_protect to use after calling copy.
   Sets *NEW_DST to 1 if this function creates parent of CONST_DIRPATH.

   Return 0 if parent of CONST_DIRPATH exists as a directory with the proper
   permissions when done, otherwise 1. */

static int
make_path_private (const char *const_dirpath, int src_offset, int mode,
		   const char *verbose_fmt_string, struct dir_attr **attr_list,
		   int *new_dst)
{
  struct stat stats;
  char *dirpath;		/* A copy of CONST_DIRPATH we can change. */
  char *src;			/* Source name in `dirpath'. */
  char *tmp_dst_dirname;	/* Leading path of `dirpath', malloc. */
  char *dst_dirname;		/* Leading path of `dirpath', alloca. */

  dirpath = (char *) alloca (strlen (const_dirpath) + 1);
  strcpy (dirpath, const_dirpath);

  src = dirpath + src_offset;

  tmp_dst_dirname = dirname (dirpath);
  dst_dirname = (char *) alloca (strlen (tmp_dst_dirname) + 1);
  strcpy (dst_dirname, tmp_dst_dirname);
  free (tmp_dst_dirname);

  *attr_list = NULL;

  if ((*xstat) (dst_dirname, &stats))
    {
      /* Parent of CONST_DIRNAME does not exist.
	 Make all missing intermediate directories. */
      char *slash;

      slash = src;
      while (*slash == '/')
	slash++;
      while ((slash = strchr (slash, '/')))
	{
	  /* Add this directory to the list of directories whose modes need
	     fixing later. */
	  struct dir_attr *new =
	    (struct dir_attr *) xmalloc (sizeof (struct dir_attr));
	  new->slash_offset = slash - dirpath;
	  new->next = *attr_list;
	  *attr_list = new;

	  *slash = '\0';
	  if ((*xstat) (dirpath, &stats))
	    {
	      /* This element of the path does not exist.  We must set
		 *new_dst and new->is_new_dir inside this loop because,
		 for example, in the command `cp --parents ../a/../b/c e_dir',
		 make_path_private creates only e_dir/../a if ./b already
		 exists. */
	      *new_dst = 1;
	      new->is_new_dir = 1;
	      if (mkdir (dirpath, mode))
		{
		  error (0, errno, _("cannot make directory `%s'"), dirpath);
		  return 1;
		}
	      else
		{
		  if (verbose_fmt_string != NULL)
		    printf (verbose_fmt_string, src, dirpath);
		}
	    }
	  else if (!S_ISDIR (stats.st_mode))
	    {
	      error (0, 0, _("`%s' exists but is not a directory"), dirpath);
	      return 1;
	    }
	  else
	    {
	      new->is_new_dir = 0;
	      *new_dst = 0;
	    }
	  *slash++ = '/';

	  /* Avoid unnecessary calls to `stat' when given
	     pathnames containing multiple adjacent slashes.  */
	  while (*slash == '/')
	    slash++;
	}
    }

  /* We get here if the parent of `dirpath' already exists. */

  else if (!S_ISDIR (stats.st_mode))
    {
      error (0, 0, _("`%s' exists but is not a directory"), dst_dirname);
      return 1;
    }
  else
    {
      *new_dst = 0;
    }
  return 0;
}

/* Ensure that the parent directories of CONST_DST_PATH have the
   correct protections, for the --parents option.  This is done
   after all copying has been completed, to allow permissions
   that don't include user write/execute.

   SRC_OFFSET is the index in CONST_DST_PATH of the beginning of the
   source directory name.

   ATTR_LIST is a null-terminated linked list of structures that
   indicates the end of the filename of each intermediate directory
   in CONST_DST_PATH that may need to have its attributes changed.
   The command `cp --parents --preserve a/b/c d/e_dir' changes the
   attributes of the directories d/e_dir/a and d/e_dir/a/b to match
   the corresponding source directories regardless of whether they
   existed before the `cp' command was given.

   Return 0 if the parent of CONST_DST_PATH and any intermediate
   directories specified by ATTR_LIST have the proper permissions
   when done, otherwise 1. */

static int
re_protect (const char *const_dst_path, int src_offset,
	    struct dir_attr *attr_list)
{
  struct dir_attr *p;
  char *dst_path;		/* A copy of CONST_DST_PATH we can change. */
  char *src_path;		/* The source name in `dst_path'. */

  dst_path = (char *) alloca (strlen (const_dst_path) + 1);
  strcpy (dst_path, const_dst_path);
  src_path = dst_path + src_offset;

  for (p = attr_list; p; p = p->next)
    {
      struct stat src_sb;

      dst_path[p->slash_offset] = '\0';

      if ((*xstat) (src_path, &src_sb))
	{
	  error (0, errno, "%s", src_path);
	  return 1;
	}

      /* Adjust the times (and if possible, ownership) for the copy.
	 chown turns off set[ug]id bits for non-root,
	 so do the chmod last.  */

      if (flag_preserve)
	{
	  struct utimbuf utb;

	  utb.actime = src_sb.st_atime;
	  utb.modtime = src_sb.st_mtime;

	  if (utime (dst_path, &utb))
	    {
	      error (0, errno, "%s", dst_path);
	      return 1;
	    }

	  /* If non-root uses -p, it's ok if we can't preserve ownership.
	     But root probably wants to know, e.g. if NFS disallows it.  */
	  if (chown (dst_path, src_sb.st_uid, src_sb.st_gid)
	      && (errno != EPERM || myeuid == 0))
	    {
	      error (0, errno, "%s", dst_path);
	      return 1;
	    }
	}

      if (flag_preserve || p->is_new_dir)
	{
	  if (chmod (dst_path, src_sb.st_mode & umask_kill))
	    {
	      error (0, errno, "%s", dst_path);
	      return 1;
	    }
	}

      dst_path[p->slash_offset] = '/';
    }
  return 0;
}

/* Read the contents of the directory SRC_PATH_IN, and recursively
   copy the contents to DST_PATH_IN.  NEW_DST is nonzero if
   DST_PATH_IN is a directory that was created previously in the
   recursion.   SRC_SB and ANCESTORS describe SRC_PATH_IN.
   Return 0 if successful, -1 if an error occurs. */

static int
copy_dir (const char *src_path_in, const char *dst_path_in, int new_dst,
	  const struct stat *src_sb, struct dir_list *ancestors)
{
  char *name_space;
  char *namep;
  char *src_path;
  char *dst_path;
  int ret = 0;

  errno = 0;
  name_space = savedir (src_path_in, src_sb->st_size);
  if (name_space == 0)
    {
      if (errno)
	{
	  error (0, errno, "%s", src_path_in);
	  return -1;
	}
      else
	error (1, 0, _("virtual memory exhausted"));
    }

  namep = name_space;
  while (*namep != '\0')
    {
      int fn_length = strlen (namep) + 1;

      dst_path = xmalloc (strlen (dst_path_in) + fn_length + 1);
      src_path = xmalloc (strlen (src_path_in) + fn_length + 1);

      stpcpy (stpcpy (stpcpy (src_path, src_path_in), "/"), namep);
      stpcpy (stpcpy (stpcpy (dst_path, dst_path_in), "/"), namep);

      ret |= copy (src_path, dst_path, new_dst, src_sb->st_dev, ancestors);

      /* Free the memory for `src_path'.  The memory for `dst_path'
	 cannot be deallocated, since it is used to create multiple
	 hard links.  */

      free (src_path);

      namep += fn_length;
    }
  free (name_space);
  return -ret;
}

/* Copy a regular file from SRC_PATH to DST_PATH.
   If the source file contains holes, copies holes and blocks of zeros
   in the source file as holes in the destination file.
   (Holes are read as zeroes by the `read' system call.)
   Return 0 if successful, -1 if an error occurred. */

static int
copy_reg (const char *src_path, const char *dst_path)
{
  char *buf;
  int buf_size;
  int dest_desc;
  int source_desc;
  int n_read;
  struct stat sb;
  char *cp;
  int *ip;
  int return_val = 0;
  long n_read_total = 0;
  int last_write_made_hole = 0;
  int make_holes = (flag_sparse == SPARSE_ALWAYS);

  source_desc = open (src_path, O_RDONLY);
  if (source_desc < 0)
    {
      error (0, errno, "%s", src_path);
      return -1;
    }

  /* Create the new regular file with small permissions initially,
     to not create a security hole.  */

  dest_desc = open (dst_path, O_WRONLY | O_CREAT | O_TRUNC, 0600);
  if (dest_desc < 0)
    {
      error (0, errno, _("cannot create regular file `%s'"), dst_path);
      return_val = -1;
      goto ret2;
    }

  /* Find out the optimal buffer size.  */

  if (fstat (dest_desc, &sb))
    {
      error (0, errno, "%s", dst_path);
      return_val = -1;
      goto ret;
    }

  buf_size = ST_BLKSIZE (sb);

#ifdef HAVE_ST_BLOCKS
  if (flag_sparse == SPARSE_AUTO && S_ISREG (sb.st_mode))
    {
      /* Use a heuristic to determine whether SRC_PATH contains any
	 sparse blocks. */

      if (fstat (source_desc, &sb))
	{
	  error (0, errno, "%s", src_path);
	  return_val = -1;
	  goto ret;
	}

      /* If the file has fewer blocks than would normally
	 be needed for a file of its size, then
	 at least one of the blocks in the file is a hole. */
      if (S_ISREG (sb.st_mode)
	  && (size_t) (sb.st_size / 512) > (size_t) ST_NBLOCKS (sb))
	make_holes = 1;
    }
#endif

  /* Make a buffer with space for a sentinel at the end.  */

  buf = (char *) alloca (buf_size + sizeof (int));

  for (;;)
    {
      n_read = read (source_desc, buf, buf_size);
      if (n_read < 0)
	{
#ifdef EINTR
	  if (errno == EINTR)
	    continue;
#endif
	  error (0, errno, "%s", src_path);
	  return_val = -1;
	  goto ret;
	}
      if (n_read == 0)
	break;

      n_read_total += n_read;

      ip = 0;
      if (make_holes)
	{
	  buf[n_read] = 1;	/* Sentinel to stop loop.  */

	  /* Find first nonzero *word*, or the word with the sentinel.  */

	  ip = (int *) buf;
	  while (*ip++ == 0)
	    ;

	  /* Find the first nonzero *byte*, or the sentinel.  */

	  cp = (char *) (ip - 1);
	  while (*cp++ == 0)
	    ;

	  /* If we found the sentinel, the whole input block was zero,
	     and we can make a hole.  */

	  if (cp > buf + n_read)
	    {
	      /* Make a hole.  */
	      if (lseek (dest_desc, (off_t) n_read, SEEK_CUR) < 0L)
		{
		  error (0, errno, "%s", dst_path);
		  return_val = -1;
		  goto ret;
		}
	      last_write_made_hole = 1;
	    }
	  else
	    /* Clear to indicate that a normal write is needed. */
	    ip = 0;
	}
      if (ip == 0)
	{
	  if (full_write (dest_desc, buf, n_read) < 0)
	    {
	      error (0, errno, "%s", dst_path);
	      return_val = -1;
	      goto ret;
	    }
	  last_write_made_hole = 0;
	}
    }

  /* If the file ends with a `hole', something needs to be written at
     the end.  Otherwise the kernel would truncate the file at the end
     of the last write operation.  */

  if (last_write_made_hole)
    {
#ifdef HAVE_FTRUNCATE
      /* Write a null character and truncate it again.  */
      if (full_write (dest_desc, "", 1) < 0
	  || ftruncate (dest_desc, n_read_total) < 0)
#else
      /* Seek backwards one character and write a null.  */
      if (lseek (dest_desc, (off_t) -1, SEEK_CUR) < 0L
	  || full_write (dest_desc, "", 1) < 0)
#endif
	{
	  error (0, errno, "%s", dst_path);
	  return_val = -1;
	}
    }

ret:
  if (close (dest_desc) < 0)
    {
      error (0, errno, "%s", dst_path);
      return_val = -1;
    }
ret2:
  if (close (source_desc) < 0)
    {
      error (0, errno, "%s", src_path);
      return_val = -1;
    }

  return return_val;
}