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 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 2, 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    59 Temple Place - Suite 330, Boston, MA 02111-1307, 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   xheader_write_global ();
 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                     && s.st_mtime <= current_stat_info.stat.st_mtime)
 142                   add_avoided_name (current_stat_info.file_name);
 143               }
 144
 145             skip_member ();
 146             break;
 147           }
 148
 149         case HEADER_ZERO_BLOCK:
 150           current_block = current_header;
 151           found_end = true;
 152           break;
 153
 154         case HEADER_END_OF_FILE:
 155           found_end = true;
 156           break;
 157
 158         case HEADER_FAILURE:
 159           set_next_block_after (current_header);
 160           switch (previous_status)
 161             {
 162             case HEADER_STILL_UNREAD:
 163               WARN ((0, 0, _("This does not look like a tar archive")));
 164               /* Fall through.  */
 165
 166             case HEADER_SUCCESS:
 167             case HEADER_ZERO_BLOCK:
 168               ERROR ((0, 0, _("Skipping to next header")));
 169               /* Fall through.  */
 170
 171             case HEADER_FAILURE:
 172               break;
 173
 174             case HEADER_END_OF_FILE:
 175             case HEADER_SUCCESS_EXTENDED:
 176               abort ();
 177             }
 178           break;
 179         }
 180
 181       tar_stat_destroy (&current_stat_info);
 182       xheader_destroy (&extended_header);
 183       previous_status = status;
 184     }
 185
 186   reset_eof ();
 187   time_to_start_writing = true;
 188   output_start = current_block->buffer;
 189
 190   {
 191     char *file_name;
 192
 193     while ((file_name = name_from_list ()) != NULL)
 194       {
 195         if (excluded_name (file_name))
 196           continue;
 197         if (interactive_option && !confirm ("add", file_name))
 198           continue;
 199         if (subcommand_option == CAT_SUBCOMMAND)
 200           append_file (file_name);
 201         else
 202           dump_file (file_name, 1, (dev_t) 0);
 203       }
 204   }
 205
 206   write_eot ();
 207   close_archive ();
 208   names_notfound ();
 209 }