diff options
Diffstat (limited to 'src/update.c')
| -rw-r--r-- | src/update.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/src/update.c b/src/update.c new file mode 100644 index 0000000..fa18c1d --- /dev/null +++ b/src/update.c @@ -0,0 +1,210 @@ +/* Update a tar archive. + + Copyright (C) 1988, 1992, 1994, 1996, 1997, 1999, 2000, 2001, 2003, + 2004, 2005 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by the + Free Software Foundation; either version 2, or (at your option) any later + version. + + This program is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General + Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Implement the 'r', 'u' and 'A' options for tar. 'A' means that the + file names are tar files, and they should simply be appended to the end + of the archive. No attempt is made to record the reads from the args; if + they're on raw tape or something like that, it'll probably lose... */ + +#include <system.h> +#include <quotearg.h> +#include "common.h" + +/* FIXME: This module should not directly handle the following variable, + instead, this should be done in buffer.c only. */ +extern union block *current_block; + +/* We've hit the end of the old stuff, and its time to start writing new + stuff to the tape. This involves seeking back one record and + re-writing the current record (which has been changed). + FIXME: Either eliminate it or move it to common.h. +*/ +bool time_to_start_writing; + +/* Pointer to where we started to write in the first record we write out. + This is used if we can't backspace the output and have to null out the + first part of the record. */ +char *output_start; + +/* Catenate file FILE_NAME to the archive without creating a header for it. + It had better be a tar file or the archive is screwed. */ +static void +append_file (char *file_name) +{ + int handle = open (file_name, O_RDONLY | O_BINARY); + struct stat stat_data; + + if (handle < 0) + { + open_error (file_name); + return; + } + + if (fstat (handle, &stat_data) != 0) + stat_error (file_name); + else + { + off_t bytes_left = stat_data.st_size; + + while (bytes_left > 0) + { + union block *start = find_next_block (); + size_t buffer_size = available_space_after (start); + size_t status; + char buf[UINTMAX_STRSIZE_BOUND]; + + if (bytes_left < buffer_size) + { + buffer_size = bytes_left; + status = buffer_size % BLOCKSIZE; + if (status) + memset (start->buffer + bytes_left, 0, BLOCKSIZE - status); + } + + status = safe_read (handle, start->buffer, buffer_size); + if (status == SAFE_READ_ERROR) + read_fatal_details (file_name, stat_data.st_size - bytes_left, + buffer_size); + if (status == 0) + FATAL_ERROR ((0, 0, + ngettext ("%s: File shrank by %s byte", + "%s: File shrank by %s bytes", + bytes_left), + quotearg_colon (file_name), + STRINGIFY_BIGINT (bytes_left, buf))); + + bytes_left -= status; + + set_next_block_after (start + (status - 1) / BLOCKSIZE); + } + } + + if (close (handle) != 0) + close_error (file_name); +} + +/* Implement the 'r' (add files to end of archive), and 'u' (add files + to end of archive if they aren't there, or are more up to date than + the version in the archive) commands. */ +void +update_archive (void) +{ + enum read_header previous_status = HEADER_STILL_UNREAD; + bool found_end = false; + + name_gather (); + open_archive (ACCESS_UPDATE); + buffer_write_global_xheader (); + + while (!found_end) + { + enum read_header status = read_header (false); + + switch (status) + { + case HEADER_STILL_UNREAD: + case HEADER_SUCCESS_EXTENDED: + abort (); + + case HEADER_SUCCESS: + { + struct name *name; + + decode_header (current_header, ¤t_stat_info, + ¤t_format, 0); + archive_format = current_format; + + if (subcommand_option == UPDATE_SUBCOMMAND + && (name = name_scan (current_stat_info.file_name)) != NULL) + { + struct stat s; + + chdir_do (name->change_dir); + if (deref_stat (dereference_option, + current_stat_info.file_name, &s) == 0 + && (tar_timespec_cmp (get_stat_mtime (&s), + current_stat_info.mtime) + <= 0)) + add_avoided_name (current_stat_info.file_name); + } + + skip_member (); + break; + } + + case HEADER_ZERO_BLOCK: + current_block = current_header; + found_end = true; + break; + + case HEADER_END_OF_FILE: + found_end = true; + break; + + case HEADER_FAILURE: + set_next_block_after (current_header); + switch (previous_status) + { + case HEADER_STILL_UNREAD: + WARN ((0, 0, _("This does not look like a tar archive"))); + /* Fall through. */ + + case HEADER_SUCCESS: + case HEADER_ZERO_BLOCK: + ERROR ((0, 0, _("Skipping to next header"))); + /* Fall through. */ + + case HEADER_FAILURE: + break; + + case HEADER_END_OF_FILE: + case HEADER_SUCCESS_EXTENDED: + abort (); + } + break; + } + + tar_stat_destroy (¤t_stat_info); + previous_status = status; + } + + reset_eof (); + time_to_start_writing = true; + output_start = current_block->buffer; + + { + char *file_name; + + while ((file_name = name_from_list ()) != NULL) + { + if (excluded_name (file_name)) + continue; + if (interactive_option && !confirm ("add", file_name)) + continue; + if (subcommand_option == CAT_SUBCOMMAND) + append_file (file_name); + else + dump_file (file_name, 1, (dev_t) 0); + } + } + + write_eot (); + close_archive (); + names_notfound (); +} |