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    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           ssize_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 < 0)
  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
 114   while (!found_end)
 115     {
 116       enum read_header status = read_header (false);
 117
 118       switch (status)
 119         {
 120         case HEADER_STILL_UNREAD:
 121         case HEADER_SUCCESS_EXTENDED:
 122           abort ();
 123
 124         case HEADER_SUCCESS:
 125           {
 126             struct name *name;
 127
 128             if (subcommand_option == UPDATE_SUBCOMMAND
 129                 && (name = name_scan (current_stat_info.file_name)) != NULL)
 130               {
 131                 struct stat s;
 132                 enum archive_format unused;
 133
 134                 decode_header (current_header, &current_stat_info, &unused, 0);
 135                 chdir_do (name->change_dir);
 136                 if (deref_stat (dereference_option,
 137                                 current_stat_info.file_name, &s) == 0
 138                     && s.st_mtime <= current_stat_info.stat.st_mtime)
 139                   add_avoided_name (current_stat_info.file_name);
 140               }
 141             skip_member ();
 142             break;
 143           }
 144
 145         case HEADER_ZERO_BLOCK:
 146           current_block = current_header;
 147           found_end = 1;
 148           break;
 149
 150         case HEADER_END_OF_FILE:
 151           found_end = 1;
 152           break;
 153
 154         case HEADER_FAILURE:
 155           set_next_block_after (current_header);
 156           switch (previous_status)
 157             {
 158             case HEADER_STILL_UNREAD:
 159               WARN ((0, 0, _("This does not look like a tar archive")));
 160               /* Fall through.  */
 161
 162             case HEADER_SUCCESS:
 163             case HEADER_ZERO_BLOCK:
 164               ERROR ((0, 0, _("Skipping to next header")));
 165               /* Fall through.  */
 166
 167             case HEADER_FAILURE:
 168               break;
 169
 170             case HEADER_END_OF_FILE:
 171             case HEADER_SUCCESS_EXTENDED:
 172               abort ();
 173             }
 174           break;
 175         }
 176
 177       previous_status = status;
 178     }
 179
 180   reset_eof ();
 181   time_to_start_writing = true;
 182   output_start = current_block->buffer;
 183
 184   {
 185     char *path;
 186
 187     while ((path = name_from_list ()) != NULL)
 188       {
 189         if (excluded_name (path))
 190           continue;
 191         if (interactive_option && !confirm ("add", path))
 192           continue;
 193         if (subcommand_option == CAT_SUBCOMMAND)
 194           append_file (path);
 195         else
 196           dump_file (path, 1, (dev_t) 0);
 197       }
 198   }
 199
 200   write_eot ();
 201   close_archive ();
 202   names_notfound ();
 203 }