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 int time_to_start_writing;
  37
  38 /* Pointer to where we started to write in the first record we write out.
  39    This is used if we can't backspace the output and have to null out the
  40    first part of the record.  */
  41 char *output_start;
  42
  43 /* Catenate file PATH to the archive without creating a header for it.
  44    It had better be a tar file or the archive is screwed.  */
  45 static void
  46 append_file (char *path)
  47 {
  48   int handle = open (path, O_RDONLY | O_BINARY);
  49   struct stat stat_data;
  50
  51   if (handle < 0)
  52     {
  53       open_error (path);
  54       return;
  55     }
  56
  57   if (fstat (handle, &stat_data) != 0)
  58     stat_error (path);
  59   else
  60     {
  61       off_t bytes_left = stat_data.st_size;
  62
  63       while (bytes_left > 0)
  64         {
  65           union block *start = find_next_block ();
  66           size_t buffer_size = available_space_after (start);
  67           ssize_t status;
  68           char buf[UINTMAX_STRSIZE_BOUND];
  69
  70           if (bytes_left < buffer_size)
  71             {
  72               buffer_size = bytes_left;
  73               status = buffer_size % BLOCKSIZE;
  74               if (status)
  75                 memset (start->buffer + bytes_left, 0, BLOCKSIZE - status);
  76             }
  77
  78           status = safe_read (handle, start->buffer, buffer_size);
  79           if (status < 0)
  80             read_fatal_details (path, stat_data.st_size - bytes_left,
  81                                 buffer_size);
  82           if (status == 0)
  83             FATAL_ERROR ((0, 0,
  84                           ngettext ("%s: File shrank by %s byte",
  85                                     "%s: File shrank by %s bytes",
  86                                     bytes_left),
  87                           quotearg_colon (path),
  88                           STRINGIFY_BIGINT (bytes_left, buf)));
  89
  90           bytes_left -= status;
  91
  92           set_next_block_after (start + (status - 1) / BLOCKSIZE);
  93         }
  94     }
  95
  96   if (close (handle) != 0)
  97     close_error (path);
  98 }
  99
 100 /* Implement the 'r' (add files to end of archive), and 'u' (add files
 101    to end of archive if they aren't there, or are more up to date than
 102    the version in the archive) commands.  */
 103 void
 104 update_archive (void)
 105 {
 106   enum read_header previous_status = HEADER_STILL_UNREAD;
 107   int found_end = 0;
 108
 109   name_gather ();
 110   open_archive (ACCESS_UPDATE);
 111
 112   while (!found_end)
 113     {
 114       enum read_header status = read_header (false);
 115
 116       switch (status)
 117         {
 118         case HEADER_STILL_UNREAD:
 119         case HEADER_SUCCESS_EXTENDED:
 120           abort ();
 121
 122         case HEADER_SUCCESS:
 123           {
 124             struct name *name;
 125
 126             if (subcommand_option == UPDATE_SUBCOMMAND
 127                 && (name = name_scan (current_stat_info.file_name), name))
 128               {
 129                 struct stat s;
 130                 enum archive_format unused;
 131
 132                 decode_header (current_header, &current_stat_info, &unused, 0);
 133                 chdir_do (name->change_dir);
 134                 if (deref_stat (dereference_option, current_stat_info.file_name, &s) == 0
 135                     && s.st_mtime <= current_stat_info.stat.st_mtime)
 136                   add_avoided_name (current_stat_info.file_name);
 137               }
 138             skip_member ();
 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             case HEADER_SUCCESS_EXTENDED:
 169               abort ();
 170             }
 171           break;
 172         }
 173
 174       previous_status = status;
 175     }
 176
 177   reset_eof ();
 178   time_to_start_writing = 1;
 179   output_start = current_block->buffer;
 180
 181   {
 182     char *path;
 183
 184     while (path = name_from_list (), path)
 185       {
 186         if (excluded_name (path))
 187           continue;
 188         if (interactive_option && !confirm ("add", path))
 189           continue;
 190         if (subcommand_option == CAT_SUBCOMMAND)
 191           append_file (path);
 192         else
 193           dump_file (path, 1, (dev_t) 0);
 194       }
 195   }
 196
 197   write_eot ();
 198   close_archive ();
 199   names_notfound ();
 200 }