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, 2010 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 = openat (chdir_fd, 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 (&current_header,
 118                                              &current_stat_info,
 119                                              read_header_auto);
 120
 121       switch (status)
 122         {
 123         case HEADER_STILL_UNREAD:
 124         case HEADER_SUCCESS_EXTENDED:
 125           abort ();
 126
 127         case HEADER_SUCCESS:
 128           {
 129             struct name *name;
 130
 131             decode_header (current_header, &current_stat_info,
 132                            &current_format, 0);
 133             archive_format = current_format;
 134
 135             if (subcommand_option == UPDATE_SUBCOMMAND
 136                 && (name = name_scan (current_stat_info.file_name)) != NULL)
 137               {
 138                 struct stat s;
 139
 140                 chdir_do (name->change_dir);
 141                 if (deref_stat (dereference_option,
 142                                 current_stat_info.file_name, &s) == 0)
 143                   {
 144                     if (S_ISDIR (s.st_mode))
 145                       {
 146                         char *p, *dirp;
 147                         DIR *stream;
 148                         int fd = openat (chdir_fd, name->name,
 149                                          open_read_flags | O_DIRECTORY);
 150                         if (fd < 0)
 151                           open_error (name->name);
 152                         else if (! ((stream = fdopendir (fd))
 153                                     && (dirp = streamsavedir (stream))))
 154                           savedir_error (name->name);
 155                         else
 156                           {
 157                             namebuf_t nbuf = namebuf_create (name->name);
 158
 159                             for (p = dirp; *p; p += strlen (p) + 1)
 160                               addname (namebuf_name (nbuf, p),
 161                                        0, false, NULL);
 162
 163                             namebuf_free (nbuf);
 164                             free (dirp);
 165
 166                             remname (name);
 167                           }
 168
 169                         if (stream
 170                             ? closedir (stream) != 0
 171                             : 0 <= fd && close (fd) != 0)
 172                           savedir_error (name->name);
 173                       }
 174                     else if (tar_timespec_cmp (get_stat_mtime (&s),
 175                                                current_stat_info.mtime)
 176                              <= 0)
 177                       remname (name);
 178                   }
 179               }
 180
 181             skip_member ();
 182             break;
 183           }
 184
 185         case HEADER_ZERO_BLOCK:
 186           current_block = current_header;
 187           found_end = true;
 188           break;
 189
 190         case HEADER_END_OF_FILE:
 191           found_end = true;
 192           break;
 193
 194         case HEADER_FAILURE:
 195           set_next_block_after (current_header);
 196           switch (previous_status)
 197             {
 198             case HEADER_STILL_UNREAD:
 199               WARN ((0, 0, _("This does not look like a tar archive")));
 200               /* Fall through.  */
 201
 202             case HEADER_SUCCESS:
 203             case HEADER_ZERO_BLOCK:
 204               ERROR ((0, 0, _("Skipping to next header")));
 205               /* Fall through.  */
 206
 207             case HEADER_FAILURE:
 208               break;
 209
 210             case HEADER_END_OF_FILE:
 211             case HEADER_SUCCESS_EXTENDED:
 212               abort ();
 213             }
 214           break;
 215         }
 216
 217       tar_stat_destroy (&current_stat_info);
 218       previous_status = status;
 219     }
 220
 221   reset_eof ();
 222   time_to_start_writing = true;
 223   output_start = current_block->buffer;
 224
 225   {
 226     struct name const *p;
 227     while ((p = name_from_list ()) != NULL)
 228       {
 229         char *file_name = p->name;
 230         if (excluded_name (file_name))
 231           continue;
 232         if (interactive_option && !confirm ("add", file_name))
 233           continue;
 234         if (subcommand_option == CAT_SUBCOMMAND)
 235           append_file (file_name);
 236         else
 237           dump_file (0, file_name, file_name);
 238       }
 239   }
 240
 241   write_eot ();
 242   close_archive ();
 243   finish_deferred_unlinks ();
 244   names_notfound ();
 245 }