Dogcows Code - chaz/tar/blob - src/update.c

   1 /* Update a tar archive.
   2
   3    Copyright 1988, 1992, 1994, 1996-1997, 1999-2001, 2003-2005, 2007, 2010,
   4    2013 Free Software Foundation, Inc.
   5
   6    This file is part of GNU tar.
   7
   8    GNU tar is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    GNU tar is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 /* Implement the 'r', 'u' and 'A' options for tar.  'A' means that the
  22    file names are tar files, and they should simply be appended to the end
  23    of the archive.  No attempt is made to record the reads from the args; if
  24    they're on raw tape or something like that, it'll probably lose...  */
  25
  26 #include <system.h>
  27 #include <quotearg.h>
  28 #include "common.h"
  29
  30 /* FIXME: This module should not directly handle the following variable,
  31    instead, this should be done in buffer.c only.  */
  32 extern union block *current_block;
  33
  34 /* We've hit the end of the old stuff, and its time to start writing new
  35    stuff to the tape.  This involves seeking back one record and
  36    re-writing the current record (which has been changed).
  37    FIXME: Either eliminate it or move it to common.h.
  38 */
  39 bool time_to_start_writing;
  40
  41 /* Pointer to where we started to write in the first record we write out.
  42    This is used if we can't backspace the output and have to null out the
  43    first part of the record.  */
  44 char *output_start;
  45
  46 /* Catenate file FILE_NAME to the archive without creating a header for it.
  47    It had better be a tar file or the archive is screwed.  */
  48 static void
  49 append_file (char *file_name)
  50 {
  51   int handle = openat (chdir_fd, file_name, O_RDONLY | O_BINARY);
  52   struct stat stat_data;
  53
  54   if (handle < 0)
  55     {
  56       open_error (file_name);
  57       return;
  58     }
  59
  60   if (fstat (handle, &stat_data) != 0)
  61     stat_error (file_name);
  62   else
  63     {
  64       off_t bytes_left = stat_data.st_size;
  65
  66       while (bytes_left > 0)
  67         {
  68           union block *start = find_next_block ();
  69           size_t buffer_size = available_space_after (start);
  70           size_t status;
  71           char buf[UINTMAX_STRSIZE_BOUND];
  72
  73           if (bytes_left < buffer_size)
  74             {
  75               buffer_size = bytes_left;
  76               status = buffer_size % BLOCKSIZE;
  77               if (status)
  78                 memset (start->buffer + bytes_left, 0, BLOCKSIZE - status);
  79             }
  80
  81           status = safe_read (handle, start->buffer, buffer_size);
  82           if (status == SAFE_READ_ERROR)
  83             read_fatal_details (file_name, stat_data.st_size - bytes_left,
  84                                 buffer_size);
  85           if (status == 0)
  86             FATAL_ERROR ((0, 0,
  87                           ngettext ("%s: File shrank by %s byte",
  88                                     "%s: File shrank by %s bytes",
  89                                     bytes_left),
  90                           quotearg_colon (file_name),
  91                           STRINGIFY_BIGINT (bytes_left, buf)));
  92
  93           bytes_left -= status;
  94
  95           set_next_block_after (start + (status - 1) / BLOCKSIZE);
  96         }
  97     }
  98
  99   if (close (handle) != 0)
 100     close_error (file_name);
 101 }
 102
 103 /* Implement the 'r' (add files to end of archive), and 'u' (add files
 104    to end of archive if they aren't there, or are more up to date than
 105    the version in the archive) commands.  */
 106 void
 107 update_archive (void)
 108 {
 109   enum read_header previous_status = HEADER_STILL_UNREAD;
 110   bool found_end = false;
 111
 112   name_gather ();
 113   open_archive (ACCESS_UPDATE);
 114   buffer_write_global_xheader ();
 115
 116   while (!found_end)
 117     {
 118       enum read_header status = read_header (&current_header,
 119                                              &current_stat_info,
 120                                              read_header_auto);
 121
 122       switch (status)
 123         {
 124         case HEADER_STILL_UNREAD:
 125         case HEADER_SUCCESS_EXTENDED:
 126           abort ();
 127
 128         case HEADER_SUCCESS:
 129           {
 130             struct name *name;
 131
 132             decode_header (current_header, &current_stat_info,
 133                            &current_format, 0);
 134             transform_stat_info (current_header->header.typeflag,
 135                                  &current_stat_info);
 136             archive_format = current_format;
 137
 138             if (subcommand_option == UPDATE_SUBCOMMAND
 139                 && (name = name_scan (current_stat_info.file_name)) != NULL)
 140               {
 141                 struct stat s;
 142
 143                 chdir_do (name->change_dir);
 144                 if (deref_stat (current_stat_info.file_name, &s) == 0)
 145                   {
 146                     if (S_ISDIR (s.st_mode))
 147                       {
 148                         char *p, *dirp;
 149                         DIR *stream = NULL;
 150                         int fd = openat (chdir_fd, name->name,
 151                                          open_read_flags | O_DIRECTORY);
 152                         if (fd < 0)
 153                           open_error (name->name);
 154                         else if (! ((stream = fdopendir (fd))
 155                                     && (dirp = streamsavedir (stream))))
 156                           savedir_error (name->name);
 157                         else
 158                           {
 159                             namebuf_t nbuf = namebuf_create (name->name);
 160
 161                             for (p = dirp; *p; p += strlen (p) + 1)
 162                               addname (namebuf_name (nbuf, p),
 163                                        0, false, NULL);
 164
 165                             namebuf_free (nbuf);
 166                             free (dirp);
 167
 168                             remname (name);
 169                           }
 170
 171                         if (stream
 172                             ? closedir (stream) != 0
 173                             : 0 <= fd && close (fd) != 0)
 174                           savedir_error (name->name);
 175                       }
 176                     else if (tar_timespec_cmp (get_stat_mtime (&s),
 177                                                current_stat_info.mtime)
 178                              <= 0)
 179                       remname (name);
 180                   }
 181               }
 182
 183             skip_member ();
 184             break;
 185           }
 186
 187         case HEADER_ZERO_BLOCK:
 188           current_block = current_header;
 189           found_end = true;
 190           break;
 191
 192         case HEADER_END_OF_FILE:
 193           found_end = true;
 194           break;
 195
 196         case HEADER_FAILURE:
 197           set_next_block_after (current_header);
 198           switch (previous_status)
 199             {
 200             case HEADER_STILL_UNREAD:
 201               WARN ((0, 0, _("This does not look like a tar archive")));
 202               /* Fall through.  */
 203
 204             case HEADER_SUCCESS:
 205             case HEADER_ZERO_BLOCK:
 206               ERROR ((0, 0, _("Skipping to next header")));
 207               /* Fall through.  */
 208
 209             case HEADER_FAILURE:
 210               break;
 211
 212             case HEADER_END_OF_FILE:
 213             case HEADER_SUCCESS_EXTENDED:
 214               abort ();
 215             }
 216           break;
 217         }
 218
 219       tar_stat_destroy (&current_stat_info);
 220       previous_status = status;
 221     }
 222
 223   reset_eof ();
 224   time_to_start_writing = true;
 225   output_start = current_block->buffer;
 226
 227   {
 228     struct name const *p;
 229     while ((p = name_from_list ()) != NULL)
 230       {
 231         char *file_name = p->name;
 232         if (excluded_name (file_name))
 233           continue;
 234         if (interactive_option && !confirm ("add", file_name))
 235           continue;
 236         if (subcommand_option == CAT_SUBCOMMAND)
 237           append_file (file_name);
 238         else
 239           dump_file (0, file_name, file_name);
 240       }
 241   }
 242
 243   write_eot ();
 244   close_archive ();
 245   finish_deferred_unlinks ();
 246   names_notfound ();
 247 }