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 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 = open (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 (false);
 118
 119       switch (status)
 120         {
 121         case HEADER_STILL_UNREAD:
 122         case HEADER_SUCCESS_EXTENDED:
 123           abort ();
 124
 125         case HEADER_SUCCESS:
 126           {
 127             struct name *name;
 128
 129             decode_header (current_header, &current_stat_info,
 130                            &current_format, 0);
 131             archive_format = current_format;
 132
 133             if (subcommand_option == UPDATE_SUBCOMMAND
 134                 && (name = name_scan (current_stat_info.file_name)) != NULL)
 135               {
 136                 struct stat s;
 137
 138                 chdir_do (name->change_dir);
 139                 if (deref_stat (dereference_option,
 140                                 current_stat_info.file_name, &s) == 0
 141                     && (tar_timespec_cmp (get_stat_mtime (&s),
 142                                           current_stat_info.mtime)
 143                         <= 0))
 144                   add_avoided_name (current_stat_info.file_name);
 145               }
 146
 147             skip_member ();
 148             break;
 149           }
 150
 151         case HEADER_ZERO_BLOCK:
 152           current_block = current_header;
 153           found_end = true;
 154           break;
 155
 156         case HEADER_END_OF_FILE:
 157           found_end = true;
 158           break;
 159
 160         case HEADER_FAILURE:
 161           set_next_block_after (current_header);
 162           switch (previous_status)
 163             {
 164             case HEADER_STILL_UNREAD:
 165               WARN ((0, 0, _("This does not look like a tar archive")));
 166               /* Fall through.  */
 167
 168             case HEADER_SUCCESS:
 169             case HEADER_ZERO_BLOCK:
 170               ERROR ((0, 0, _("Skipping to next header")));
 171               /* Fall through.  */
 172
 173             case HEADER_FAILURE:
 174               break;
 175
 176             case HEADER_END_OF_FILE:
 177             case HEADER_SUCCESS_EXTENDED:
 178               abort ();
 179             }
 180           break;
 181         }
 182
 183       tar_stat_destroy (&current_stat_info);
 184       previous_status = status;
 185     }
 186
 187   reset_eof ();
 188   time_to_start_writing = true;
 189   output_start = current_block->buffer;
 190
 191   {
 192     char *file_name;
 193
 194     while ((file_name = name_from_list ()) != NULL)
 195       {
 196         if (excluded_name (file_name))
 197           continue;
 198         if (interactive_option && !confirm ("add", file_name))
 199           continue;
 200         if (subcommand_option == CAT_SUBCOMMAND)
 201           append_file (file_name);
 202         else
 203           dump_file (file_name, 1, (dev_t) 0);
 204       }
 205   }
 206
 207   write_eot ();
 208   close_archive ();
 209   names_notfound ();
 210 }