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

   1 /* Update a tar archive.
   2    Copyright (C) 1988, 1992, 1994, 1996, 1997 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify it
   5    under the terms of the GNU General Public License as published by the
   6    Free Software Foundation; either version 2, or (at your option) any later
   7    version.
   8
   9    This program is distributed in the hope that it will be useful, but
  10    WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
  12    Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License along
  15    with this program; if not, write to the Free Software Foundation, Inc.,
  16    59 Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Implement the 'r', 'u' and 'A' options for tar.  'A' means that the
  19    file names are tar files, and they should simply be appended to the end
  20    of the archive.  No attempt is made to record the reads from the args; if
  21    they're on raw tape or something like that, it'll probably lose...  */
  22
  23 #include "system.h"
  24 #include "common.h"
  25
  26 /* FIXME: This module should not directly handle the following variable,
  27    instead, this should be done in buffer.c only.  */
  28 extern union block *current_block;
  29
  30 /* We've hit the end of the old stuff, and its time to start writing new
  31    stuff to the tape.  This involves seeking back one record and
  32    re-writing the current record (which has been changed).  */
  33 int time_to_start_writing = 0;
  34
  35 /* Pointer to where we started to write in the first record we write out.
  36    This is used if we can't backspace the output and have to null out the
  37    first part of the record.  */
  38 char *output_start;
  39
  40 /*------------------------------------------------------------------------.
  41 | Catenate file PATH to the archive without creating a header for it.  It |
  42 | had better be a tar file or the archive is screwed.                     |
  43 `------------------------------------------------------------------------*/
  44
  45 static void
  46 append_file (char *path)
  47 {
  48   int handle;
  49   struct stat stat_data;
  50   long bytes_left;
  51
  52   if (stat (path, &stat_data) != 0
  53       || (handle = open (path, O_RDONLY | O_BINARY), handle < 0))
  54     {
  55       ERROR ((0, errno, _("Cannot open file %s"), path));
  56       return;
  57     }
  58
  59   bytes_left = stat_data.st_size;
  60
  61   while (bytes_left > 0)
  62     {
  63       union block *start = find_next_block ();
  64       long buffer_size = available_space_after (start);
  65       int status;
  66
  67       if (bytes_left < buffer_size)
  68         {
  69           buffer_size = bytes_left;
  70           status = buffer_size % BLOCKSIZE;
  71           if (status)
  72             memset (start->buffer + bytes_left, 0,
  73                     (size_t) (BLOCKSIZE - status));
  74         }
  75
  76       status = read (handle, start->buffer, (size_t) buffer_size);
  77       if (status < 0)
  78         FATAL_ERROR ((0, errno,
  79                 _("Read error at byte %ld reading %d bytes in file %s"),
  80                 stat_data.st_size - bytes_left, buffer_size, path));
  81       bytes_left -= status;
  82
  83       set_next_block_after (start + (status - 1) / BLOCKSIZE);
  84
  85       if (status != buffer_size)
  86         FATAL_ERROR ((0, 0, _("%s: File shrunk by %d bytes, (yark!)"),
  87                       path, bytes_left));
  88     }
  89
  90   close (handle);
  91 }
  92
  93 /*-----------------------------------------------------------------------.
  94 | Implement the 'r' (add files to end of archive), and 'u' (add files to |
  95 | end of archive if they arent there, or are more up to date than the    |
  96 | version in the archive.) commands.                                     |
  97 `-----------------------------------------------------------------------*/
  98
  99 void
 100 update_archive (void)
 101 {
 102   enum read_header previous_status = HEADER_STILL_UNREAD;
 103   int found_end = 0;
 104
 105   name_gather ();
 106   if (subcommand_option == UPDATE_SUBCOMMAND)
 107     name_expand ();
 108   open_archive (ACCESS_UPDATE);
 109
 110   while (!found_end)
 111     {
 112       enum read_header status = read_header ();
 113
 114       switch (status)
 115         {
 116         case HEADER_STILL_UNREAD:
 117           abort ();
 118
 119         case HEADER_SUCCESS:
 120           {
 121             struct name *name;
 122
 123             if (subcommand_option == UPDATE_SUBCOMMAND
 124                 && (name = name_scan (current_file_name), name))
 125               {
 126                 struct stat stat_data;
 127                 enum archive_format unused;
 128
 129                 decode_header (current_header, &current_stat, &unused, 0);
 130                 if (stat (current_file_name, &stat_data) < 0)
 131                   ERROR ((0, errno, _("Cannot stat %s"), current_file_name));
 132                 else if (current_stat.st_mtime >= stat_data.st_mtime)
 133                   name->found = 1;
 134               }
 135             set_next_block_after (current_header);
 136             if (current_header->oldgnu_header.isextended)
 137               skip_extended_headers ();
 138             skip_file ((long) current_stat.st_size);
 139             break;
 140           }
 141
 142         case HEADER_ZERO_BLOCK:
 143           current_block = current_header;
 144           found_end = 1;
 145           break;
 146
 147         case HEADER_END_OF_FILE:
 148           found_end = 1;
 149           break;
 150
 151         case HEADER_FAILURE:
 152           set_next_block_after (current_header);
 153           switch (previous_status)
 154             {
 155             case HEADER_STILL_UNREAD:
 156               WARN ((0, 0, _("This does not look like a tar archive")));
 157               /* Fall through.  */
 158
 159             case HEADER_SUCCESS:
 160             case HEADER_ZERO_BLOCK:
 161               ERROR ((0, 0, _("Skipping to next header")));
 162               /* Fall through.  */
 163
 164             case HEADER_FAILURE:
 165               break;
 166
 167             case HEADER_END_OF_FILE:
 168               abort ();
 169             }
 170           break;
 171         }
 172
 173       previous_status = status;
 174     }
 175
 176   reset_eof ();
 177   time_to_start_writing = 1;
 178   output_start = current_block->buffer;
 179
 180   {
 181     char *path;
 182
 183     while (path = name_from_list (), path)
 184       {
 185         if (interactive_option && !confirm ("add", path))
 186           continue;
 187         if (subcommand_option == CAT_SUBCOMMAND)
 188           append_file (path);
 189         else
 190           dump_file (path, -1, 1);
 191       }
 192   }
 193
 194   write_eot ();
 195   close_archive ();
 196   names_notfound ();
 197 }