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