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

   1 /* Update a tar archive.
   2    Copyright 1988, 92, 94, 96, 97, 99, 2000 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 Temple 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 <quotearg.h>
  25 #include "common.h"
  26
  27 /* FIXME: This module should not directly handle the following variable,
  28    instead, this should be done in buffer.c only.  */
  29 extern union block *current_block;
  30
  31 /* We've hit the end of the old stuff, and its time to start writing new
  32    stuff to the tape.  This involves seeking back one record and
  33    re-writing the current record (which has been changed).  */
  34 int time_to_start_writing;
  35
  36 /* Pointer to where we started to write in the first record we write out.
  37    This is used if we can't backspace the output and have to null out the
  38    first part of the record.  */
  39 char *output_start;
  40
  41 /* Catenate file PATH to the archive without creating a header for it.
  42    It had better be a tar file or the archive is screwed.  */
  43 static void
  44 append_file (char *path)
  45 {
  46   int handle = open (path, O_RDONLY | O_BINARY);
  47   struct stat stat_data;
  48
  49   if (handle < 0)
  50     {
  51       open_error (path);
  52       return;
  53     }
  54
  55   if (fstat (handle, &stat_data) != 0)
  56     stat_error (path);
  57   else
  58     {
  59       off_t bytes_left = stat_data.st_size;
  60
  61       while (bytes_left > 0)
  62         {
  63           union block *start = find_next_block ();
  64           size_t buffer_size = available_space_after (start);
  65           ssize_t status;
  66           char buf[UINTMAX_STRSIZE_BOUND];
  67
  68           if (bytes_left < buffer_size)
  69             {
  70               buffer_size = bytes_left;
  71               status = buffer_size % BLOCKSIZE;
  72               if (status)
  73                 memset (start->buffer + bytes_left, 0, BLOCKSIZE - status);
  74             }
  75
  76           status = safe_read (handle, start->buffer, buffer_size);
  77           if (status < 0)
  78             read_fatal_details (path, stat_data.st_size - bytes_left,
  79                                 buffer_size);
  80           if (status == 0)
  81             FATAL_ERROR ((0, 0, _("%s: File shrank by %s bytes"),
  82                           quotearg_colon (path),
  83                           STRINGIFY_BIGINT (bytes_left, buf)));
  84
  85           bytes_left -= status;
  86
  87           set_next_block_after (start + (status - 1) / BLOCKSIZE);
  88         }
  89     }
  90
  91   if (close (handle) != 0)
  92     close_error (path);
  93 }
  94
  95 /* Implement the 'r' (add files to end of archive), and 'u' (add files
  96    to end of archive if they aren't there, or are more up to date than
  97    the version in the archive) commands.  */
  98 void
  99 update_archive (void)
 100 {
 101   enum read_header previous_status = HEADER_STILL_UNREAD;
 102   int found_end = 0;
 103
 104   name_gather ();
 105   open_archive (ACCESS_UPDATE);
 106
 107   while (!found_end)
 108     {
 109       enum read_header status = read_header ();
 110
 111       switch (status)
 112         {
 113         case HEADER_STILL_UNREAD:
 114           abort ();
 115
 116         case HEADER_SUCCESS:
 117           {
 118             struct name *name;
 119
 120             if (subcommand_option == UPDATE_SUBCOMMAND
 121                 && (name = name_scan (current_file_name), name))
 122               {
 123                 struct stat s;
 124                 enum archive_format unused;
 125
 126                 decode_header (current_header, &current_stat, &unused, 0);
 127                 chdir_do (name->change_dir);
 128                 if (deref_stat (dereference_option, current_file_name, &s) == 0
 129                     && s.st_mtime <= current_stat.st_mtime)
 130                   add_avoided_name (current_file_name);
 131               }
 132             skip_member ();
 133             break;
 134           }
 135
 136         case HEADER_ZERO_BLOCK:
 137           current_block = current_header;
 138           found_end = 1;
 139           break;
 140
 141         case HEADER_END_OF_FILE:
 142           found_end = 1;
 143           break;
 144
 145         case HEADER_FAILURE:
 146           set_next_block_after (current_header);
 147           switch (previous_status)
 148             {
 149             case HEADER_STILL_UNREAD:
 150               WARN ((0, 0, _("This does not look like a tar archive")));
 151               /* Fall through.  */
 152
 153             case HEADER_SUCCESS:
 154             case HEADER_ZERO_BLOCK:
 155               ERROR ((0, 0, _("Skipping to next header")));
 156               /* Fall through.  */
 157
 158             case HEADER_FAILURE:
 159               break;
 160
 161             case HEADER_END_OF_FILE:
 162               abort ();
 163             }
 164           break;
 165         }
 166
 167       previous_status = status;
 168     }
 169
 170   reset_eof ();
 171   time_to_start_writing = 1;
 172   output_start = current_block->buffer;
 173
 174   {
 175     char *path;
 176
 177     while (path = name_from_list (), path)
 178       {
 179         if (excluded_name (path))
 180           continue;
 181         if (interactive_option && !confirm ("add", path))
 182           continue;
 183         if (subcommand_option == CAT_SUBCOMMAND)
 184           append_file (path);
 185         else
 186           dump_file (path, 1, (dev_t) 0);
 187       }
 188   }
 189
 190   write_eot ();
 191   close_archive ();
 192   names_notfound ();
 193 }