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 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 "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;
  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 = open (path, O_RDONLY | O_BINARY);
  49   struct stat stat_data;
  50
  51   if (handle < 0)
  52     {
  53       ERROR ((0, errno, _("Cannot open file %s"), path));
  54       return;
  55     }
  56
  57   if (fstat (handle, &stat_data) != 0)
  58     ERROR ((0, errno, "%s", 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             FATAL_ERROR ((0, errno,
  81                           _("Read error at byte %s reading %lu bytes in file %s"),
  82                           STRINGIFY_BIGINT (stat_data.st_size - bytes_left,
  83                                             buf),
  84                           (unsigned long) buffer_size, path));
  85           if (status == 0)
  86             FATAL_ERROR ((0, 0, _("%s: File shrunk by %s bytes, (yark!)"),
  87                           path, STRINGIFY_BIGINT (bytes_left, buf)));
  88
  89           bytes_left -= status;
  90
  91           set_next_block_after (start + (status - 1) / BLOCKSIZE);
  92         }
  93     }
  94
  95   close (handle);
  96 }
  97
  98 /*-----------------------------------------------------------------------.
  99 | Implement the 'r' (add files to end of archive), and 'u' (add files to |
 100 | end of archive if they arent there, or are more up to date than the    |
 101 | version in the archive.) commands.                                     |
 102 `-----------------------------------------------------------------------*/
 103
 104 void
 105 update_archive (void)
 106 {
 107   enum read_header previous_status = HEADER_STILL_UNREAD;
 108   int found_end = 0;
 109
 110   name_gather ();
 111   if (subcommand_option == UPDATE_SUBCOMMAND)
 112     name_expand ();
 113   open_archive (ACCESS_UPDATE);
 114
 115   while (!found_end)
 116     {
 117       enum read_header status = read_header ();
 118
 119       switch (status)
 120         {
 121         case HEADER_STILL_UNREAD:
 122           abort ();
 123
 124         case HEADER_SUCCESS:
 125           {
 126             struct name *name;
 127
 128             if (subcommand_option == UPDATE_SUBCOMMAND
 129                 && (name = name_scan (current_file_name), name))
 130               {
 131                 struct stat stat_data;
 132                 enum archive_format unused;
 133
 134                 decode_header (current_header, &current_stat, &unused, 0);
 135                 if (stat (current_file_name, &stat_data) < 0)
 136                   ERROR ((0, errno, _("Cannot stat %s"), current_file_name));
 137                 else if (current_stat.st_mtime >= stat_data.st_mtime)
 138                   name->found = 1;
 139               }
 140             set_next_block_after (current_header);
 141             if (current_header->oldgnu_header.isextended)
 142               skip_extended_headers ();
 143             skip_file (current_stat.st_size);
 144             break;
 145           }
 146
 147         case HEADER_ZERO_BLOCK:
 148           current_block = current_header;
 149           found_end = 1;
 150           break;
 151
 152         case HEADER_END_OF_FILE:
 153           found_end = 1;
 154           break;
 155
 156         case HEADER_FAILURE:
 157           set_next_block_after (current_header);
 158           switch (previous_status)
 159             {
 160             case HEADER_STILL_UNREAD:
 161               WARN ((0, 0, _("This does not look like a tar archive")));
 162               /* Fall through.  */
 163
 164             case HEADER_SUCCESS:
 165             case HEADER_ZERO_BLOCK:
 166               ERROR ((0, 0, _("Skipping to next header")));
 167               /* Fall through.  */
 168
 169             case HEADER_FAILURE:
 170               break;
 171
 172             case HEADER_END_OF_FILE:
 173               abort ();
 174             }
 175           break;
 176         }
 177
 178       previous_status = status;
 179     }
 180
 181   reset_eof ();
 182   time_to_start_writing = 1;
 183   output_start = current_block->buffer;
 184
 185   {
 186     char *path;
 187
 188     while (path = name_from_list (), path)
 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, (dev_t) -1, 1);
 198       }
 199   }
 200
 201   write_eot ();
 202   close_archive ();
 203   names_notfound ();
 204 }