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 PATH 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 *path)
  49 {
  50   int handle = open (path, O_RDONLY | O_BINARY);
  51   struct stat stat_data;
  52
  53   if (handle < 0)
  54     {
  55       open_error (path);
  56       return;
  57     }
  58
  59   if (fstat (handle, &stat_data) != 0)
  60     stat_error (path);
  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 (path, 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 (path),
  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 (path);
 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   int found_end = 0;
 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             if (subcommand_option == UPDATE_SUBCOMMAND
 130                 && (name = name_scan (current_stat_info.file_name)) != NULL)
 131               {
 132                 struct stat s;
 133                 enum archive_format unused;
 134
 135                 decode_header (current_header, &current_stat_info, &unused, 0);
 136                 chdir_do (name->change_dir);
 137                 if (deref_stat (dereference_option,
 138                                 current_stat_info.file_name, &s) == 0
 139                     && s.st_mtime <= current_stat_info.stat.st_mtime)
 140                   add_avoided_name (current_stat_info.file_name);
 141               }
 142             skip_member ();
 143             break;
 144           }
 145
 146         case HEADER_ZERO_BLOCK:
 147           current_block = current_header;
 148           found_end = 1;
 149           break;
 150
 151         case HEADER_END_OF_FILE:
 152           found_end = 1;
 153           break;
 154
 155         case HEADER_FAILURE:
 156           set_next_block_after (current_header);
 157           switch (previous_status)
 158             {
 159             case HEADER_STILL_UNREAD:
 160               WARN ((0, 0, _("This does not look like a tar archive")));
 161               /* Fall through.  */
 162
 163             case HEADER_SUCCESS:
 164             case HEADER_ZERO_BLOCK:
 165               ERROR ((0, 0, _("Skipping to next header")));
 166               /* Fall through.  */
 167
 168             case HEADER_FAILURE:
 169               break;
 170
 171             case HEADER_END_OF_FILE:
 172             case HEADER_SUCCESS_EXTENDED:
 173               abort ();
 174             }
 175           break;
 176         }
 177
 178       previous_status = status;
 179     }
 180
 181   reset_eof ();
 182   time_to_start_writing = true;
 183   output_start = current_block->buffer;
 184
 185   {
 186     char *path;
 187
 188     while ((path = name_from_list ()) != NULL)
 189       {
 190         if (excluded_name (path))
 191           continue;
 192         if (interactive_option && !confirm ("add", path))
 193           continue;
 194         if (subcommand_option == CAT_SUBCOMMAND)
 195           append_file (path);
 196         else
 197           dump_file (path, 1, (dev_t) 0);
 198       }
 199   }
 200
 201   write_eot ();
 202   close_archive ();
 203   names_notfound ();
 204 }