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