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

   1 /* Update a tar archive.
   2
   3    Copyright (C) 1988, 1992, 1994, 1996, 1997, 1999, 2000, 2001, 2003,
   4    2004, 2005, 2007, 2010 Free Software Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by the
   8    Free Software Foundation; either version 3, or (at your option) any later
   9    version.
  10
  11    This program is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
  14    Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License along
  17    with this program; if not, write to the Free Software Foundation, Inc.,
  18    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  19
  20 /* Implement the 'r', 'u' and 'A' options for tar.  'A' means that the
  21    file names are tar files, and they should simply be appended to the end
  22    of the archive.  No attempt is made to record the reads from the args; if
  23    they're on raw tape or something like that, it'll probably lose...  */
  24
  25 #include <system.h>
  26 #include <quotearg.h>
  27 #include "common.h"
  28
  29 /* FIXME: This module should not directly handle the following variable,
  30    instead, this should be done in buffer.c only.  */
  31 extern union block *current_block;
  32
  33 /* We've hit the end of the old stuff, and its time to start writing new
  34    stuff to the tape.  This involves seeking back one record and
  35    re-writing the current record (which has been changed).
  36    FIXME: Either eliminate it or move it to common.h.
  37 */
  38 bool time_to_start_writing;
  39
  40 /* Pointer to where we started to write in the first record we write out.
  41    This is used if we can't backspace the output and have to null out the
  42    first part of the record.  */
  43 char *output_start;
  44
  45 /* Catenate file FILE_NAME to the archive without creating a header for it.
  46    It had better be a tar file or the archive is screwed.  */
  47 static void
  48 append_file (char *file_name)
  49 {
  50   int handle = openat (chdir_fd, file_name, O_RDONLY | O_BINARY);
  51   struct stat stat_data;
  52
  53   if (handle < 0)
  54     {
  55       open_error (file_name);
  56       return;
  57     }
  58
  59   if (fstat (handle, &stat_data) != 0)
  60     stat_error (file_name);
  61   else
  62     {
  63       off_t bytes_left = stat_data.st_size;
  64
  65       while (bytes_left > 0)
  66         {
  67           union block *start = find_next_block ();
  68           size_t buffer_size = available_space_after (start);
  69           size_t status;
  70           char buf[UINTMAX_STRSIZE_BOUND];
  71
  72           if (bytes_left < buffer_size)
  73             {
  74               buffer_size = bytes_left;
  75               status = buffer_size % BLOCKSIZE;
  76               if (status)
  77                 memset (start->buffer + bytes_left, 0, BLOCKSIZE - status);
  78             }
  79
  80           status = safe_read (handle, start->buffer, buffer_size);
  81           if (status == SAFE_READ_ERROR)
  82             read_fatal_details (file_name, stat_data.st_size - bytes_left,
  83                                 buffer_size);
  84           if (status == 0)
  85             FATAL_ERROR ((0, 0,
  86                           ngettext ("%s: File shrank by %s byte",
  87                                     "%s: File shrank by %s bytes",
  88                                     bytes_left),
  89                           quotearg_colon (file_name),
  90                           STRINGIFY_BIGINT (bytes_left, buf)));
  91
  92           bytes_left -= status;
  93
  94           set_next_block_after (start + (status - 1) / BLOCKSIZE);
  95         }
  96     }
  97
  98   if (close (handle) != 0)
  99     close_error (file_name);
 100 }
 101
 102 /* Implement the 'r' (add files to end of archive), and 'u' (add files
 103    to end of archive if they aren't there, or are more up to date than
 104    the version in the archive) commands.  */
 105 void
 106 update_archive (void)
 107 {
 108   enum read_header previous_status = HEADER_STILL_UNREAD;
 109   bool found_end = false;
 110
 111   name_gather ();
 112   open_archive (ACCESS_UPDATE);
 113   buffer_write_global_xheader ();
 114
 115   while (!found_end)
 116     {
 117       enum read_header status = read_header (&current_header,
 118                                              &current_stat_info,
 119                                              read_header_auto);
 120
 121       switch (status)
 122         {
 123         case HEADER_STILL_UNREAD:
 124         case HEADER_SUCCESS_EXTENDED:
 125           abort ();
 126
 127         case HEADER_SUCCESS:
 128           {
 129             struct name *name;
 130
 131             decode_header (current_header, &current_stat_info,
 132                            &current_format, 0);
 133             transform_stat_info (current_header->header.typeflag,
 134                                  &current_stat_info);
 135             archive_format = current_format;
 136
 137             if (subcommand_option == UPDATE_SUBCOMMAND
 138                 && (name = name_scan (current_stat_info.file_name)) != NULL)
 139               {
 140                 struct stat s;
 141
 142                 chdir_do (name->change_dir);
 143                 if (deref_stat (current_stat_info.file_name, &s) == 0)
 144                   {
 145                     if (S_ISDIR (s.st_mode))
 146                       {
 147                         char *p, *dirp;
 148                         DIR *stream;
 149                         int fd = openat (chdir_fd, name->name,
 150                                          open_read_flags | O_DIRECTORY);
 151                         if (fd < 0)
 152                           open_error (name->name);
 153                         else if (! ((stream = fdopendir (fd))
 154                                     && (dirp = streamsavedir (stream))))
 155                           savedir_error (name->name);
 156                         else
 157                           {
 158                             namebuf_t nbuf = namebuf_create (name->name);
 159
 160                             for (p = dirp; *p; p += strlen (p) + 1)
 161                               addname (namebuf_name (nbuf, p),
 162                                        0, false, NULL);
 163
 164                             namebuf_free (nbuf);
 165                             free (dirp);
 166
 167                             remname (name);
 168                           }
 169
 170                         if (stream
 171                             ? closedir (stream) != 0
 172                             : 0 <= fd && close (fd) != 0)
 173                           savedir_error (name->name);
 174                       }
 175                     else if (tar_timespec_cmp (get_stat_mtime (&s),
 176                                                current_stat_info.mtime)
 177                              <= 0)
 178                       remname (name);
 179                   }
 180               }
 181
 182             skip_member ();
 183             break;
 184           }
 185
 186         case HEADER_ZERO_BLOCK:
 187           current_block = current_header;
 188           found_end = true;
 189           break;
 190
 191         case HEADER_END_OF_FILE:
 192           found_end = true;
 193           break;
 194
 195         case HEADER_FAILURE:
 196           set_next_block_after (current_header);
 197           switch (previous_status)
 198             {
 199             case HEADER_STILL_UNREAD:
 200               WARN ((0, 0, _("This does not look like a tar archive")));
 201               /* Fall through.  */
 202
 203             case HEADER_SUCCESS:
 204             case HEADER_ZERO_BLOCK:
 205               ERROR ((0, 0, _("Skipping to next header")));
 206               /* Fall through.  */
 207
 208             case HEADER_FAILURE:
 209               break;
 210
 211             case HEADER_END_OF_FILE:
 212             case HEADER_SUCCESS_EXTENDED:
 213               abort ();
 214             }
 215           break;
 216         }
 217
 218       tar_stat_destroy (&current_stat_info);
 219       previous_status = status;
 220     }
 221
 222   reset_eof ();
 223   time_to_start_writing = true;
 224   output_start = current_block->buffer;
 225
 226   {
 227     struct name const *p;
 228     while ((p = name_from_list ()) != NULL)
 229       {
 230         char *file_name = p->name;
 231         if (excluded_name (file_name))
 232           continue;
 233         if (interactive_option && !confirm ("add", file_name))
 234           continue;
 235         if (subcommand_option == CAT_SUBCOMMAND)
 236           append_file (file_name);
 237         else
 238           dump_file (0, file_name, file_name);
 239       }
 240   }
 241
 242   write_eot ();
 243   close_archive ();
 244   finish_deferred_unlinks ();
 245   names_notfound ();
 246 }