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    2004, 2005, 2007 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 3, 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    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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 FILE_NAME 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 *file_name)
  49 {
  50   int handle = open (file_name, O_RDONLY | O_BINARY);
  51   struct stat stat_data;
  52
  53   if (handle < 0)
  54     {
  55       open_error (file_name);
  56       return;
  57     }
  58
  59   if (fstat (handle, &stat_data) != 0)
  60     stat_error (file_name);
  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           size_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 == SAFE_READ_ERROR)
  82             read_fatal_details (file_name, 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 (file_name),
  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 (file_name);
 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   bool found_end = false;
 110
 111   name_gather ();
 112   open_archive (ACCESS_UPDATE);
 113   buffer_write_global_xheader ();
 114
 115   while (!found_end)
 116     {
 117       enum read_header status = read_header (false);
 118
 119       switch (status)
 120         {
 121         case HEADER_STILL_UNREAD:
 122         case HEADER_SUCCESS_EXTENDED:
 123           abort ();
 124
 125         case HEADER_SUCCESS:
 126           {
 127             struct name *name;
 128
 129             decode_header (current_header, &current_stat_info,
 130                            &current_format, 0);
 131             archive_format = current_format;
 132
 133             if (subcommand_option == UPDATE_SUBCOMMAND
 134                 && (name = name_scan (current_stat_info.file_name)) != NULL)
 135               {
 136                 struct stat s;
 137
 138                 chdir_do (name->change_dir);
 139                 if (deref_stat (dereference_option,
 140                                 current_stat_info.file_name, &s) == 0)
 141                   {
 142                     if (S_ISDIR (s.st_mode))
 143                       {
 144                         char *p, *dirp;
 145                         dirp = savedir (name->name);
 146                         if (!dirp)
 147                           savedir_error (name->name);
 148                         else
 149                           {
 150                             namebuf_t nbuf = namebuf_create (name->name);
 151
 152                             for (p = dirp; *p; p += strlen (p) + 1)
 153                               addname (namebuf_name (nbuf, p),
 154                                        0, false, NULL);
 155
 156                             namebuf_free (nbuf);
 157                             free (dirp);
 158
 159                             remname (name);
 160                           }
 161                       }
 162                     else if (tar_timespec_cmp (get_stat_mtime (&s),
 163                                                current_stat_info.mtime)
 164                              <= 0)
 165                       remname (name);
 166                   }
 167               }
 168
 169             skip_member ();
 170             break;
 171           }
 172
 173         case HEADER_ZERO_BLOCK:
 174           current_block = current_header;
 175           found_end = true;
 176           break;
 177
 178         case HEADER_END_OF_FILE:
 179           found_end = true;
 180           break;
 181
 182         case HEADER_FAILURE:
 183           set_next_block_after (current_header);
 184           switch (previous_status)
 185             {
 186             case HEADER_STILL_UNREAD:
 187               WARN ((0, 0, _("This does not look like a tar archive")));
 188               /* Fall through.  */
 189
 190             case HEADER_SUCCESS:
 191             case HEADER_ZERO_BLOCK:
 192               ERROR ((0, 0, _("Skipping to next header")));
 193               /* Fall through.  */
 194
 195             case HEADER_FAILURE:
 196               break;
 197
 198             case HEADER_END_OF_FILE:
 199             case HEADER_SUCCESS_EXTENDED:
 200               abort ();
 201             }
 202           break;
 203         }
 204
 205       tar_stat_destroy (&current_stat_info);
 206       previous_status = status;
 207     }
 208
 209   reset_eof ();
 210   time_to_start_writing = true;
 211   output_start = current_block->buffer;
 212
 213   {
 214     struct name const *p;
 215     while ((p = name_from_list ()) != NULL)
 216       {
 217         char *file_name = p->name;
 218         if (excluded_name (file_name))
 219           continue;
 220         if (interactive_option && !confirm ("add", file_name))
 221           continue;
 222         if (subcommand_option == CAT_SUBCOMMAND)
 223           append_file (file_name);
 224         else
 225           dump_file (file_name, 1, (dev_t) 0);
 226       }
 227   }
 228
 229   write_eot ();
 230   close_archive ();
 231   names_notfound ();
 232 }