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,
   4    2010, 2013-2014 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 = tar_savedir (name->name, 1);
 149                         if (dirp)
 150                           {
 151                             namebuf_t nbuf = namebuf_create (name->name);
 152
 153                             for (p = dirp; *p; p += strlen (p) + 1)
 154                               addname (namebuf_name (nbuf, p),
 155                                        0, false, NULL);
 156
 157                             namebuf_free (nbuf);
 158                             free (dirp);
 159
 160                             remname (name);
 161                           }
 162                       }
 163                     else if (tar_timespec_cmp (get_stat_mtime (&s),
 164                                                current_stat_info.mtime)
 165                              <= 0)
 166                       remname (name);
 167                   }
 168               }
 169
 170             skip_member ();
 171             break;
 172           }
 173
 174         case HEADER_ZERO_BLOCK:
 175           current_block = current_header;
 176           found_end = true;
 177           break;
 178
 179         case HEADER_END_OF_FILE:
 180           found_end = true;
 181           break;
 182
 183         case HEADER_FAILURE:
 184           set_next_block_after (current_header);
 185           switch (previous_status)
 186             {
 187             case HEADER_STILL_UNREAD:
 188               WARN ((0, 0, _("This does not look like a tar archive")));
 189               /* Fall through.  */
 190
 191             case HEADER_SUCCESS:
 192             case HEADER_ZERO_BLOCK:
 193               ERROR ((0, 0, _("Skipping to next header")));
 194               /* Fall through.  */
 195
 196             case HEADER_FAILURE:
 197               break;
 198
 199             case HEADER_END_OF_FILE:
 200             case HEADER_SUCCESS_EXTENDED:
 201               abort ();
 202             }
 203           break;
 204         }
 205
 206       tar_stat_destroy (&current_stat_info);
 207       previous_status = status;
 208     }
 209
 210   reset_eof ();
 211   time_to_start_writing = true;
 212   output_start = current_block->buffer;
 213
 214   {
 215     struct name const *p;
 216     while ((p = name_from_list ()) != NULL)
 217       {
 218         char *file_name = p->name;
 219         if (excluded_name (file_name))
 220           continue;
 221         if (interactive_option && !confirm ("add", file_name))
 222           continue;
 223         if (subcommand_option == CAT_SUBCOMMAND)
 224           append_file (file_name);
 225         else
 226           dump_file (0, file_name, file_name);
 227       }
 228   }
 229
 230   write_eot ();
 231   close_archive ();
 232   finish_deferred_unlinks ();
 233   names_notfound ();
 234 }