diff options
Diffstat (limited to 'contrib/tar/src/update.c')
| -rw-r--r-- | contrib/tar/src/update.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/contrib/tar/src/update.c b/contrib/tar/src/update.c new file mode 100644 index 0000000..754d321 --- /dev/null +++ b/contrib/tar/src/update.c @@ -0,0 +1,195 @@ +/* Update a tar archive. + + Copyright (C) 1988, 1992, 1994, 1996, 1997, 1999, 2000, 2001 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., + 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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). */ +int 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 PATH 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 *path) +{ + int handle = open (path, O_RDONLY | O_BINARY); + struct stat stat_data; + + if (handle < 0) + { + open_error (path); + return; + } + + if (fstat (handle, &stat_data) != 0) + stat_error (path); + 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); + ssize_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 < 0) + read_fatal_details (path, stat_data.st_size - bytes_left, + buffer_size); + if (status == 0) + FATAL_ERROR ((0, 0, _("%s: File shrank by %s bytes"), + quotearg_colon (path), + STRINGIFY_BIGINT (bytes_left, buf))); + + bytes_left -= status; + + set_next_block_after (start + (status - 1) / BLOCKSIZE); + } + } + + if (close (handle) != 0) + close_error (path); +} + +/* 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; + int found_end = 0; + + name_gather (); + open_archive (ACCESS_UPDATE); + + while (!found_end) + { + enum read_header status = read_header (0); + + switch (status) + { + case HEADER_STILL_UNREAD: + abort (); + + case HEADER_SUCCESS: + { + struct name *name; + + if (subcommand_option == UPDATE_SUBCOMMAND + && (name = name_scan (current_file_name), name)) + { + struct stat s; + enum archive_format unused; + + decode_header (current_header, ¤t_stat, &unused, 0); + chdir_do (name->change_dir); + if (deref_stat (dereference_option, current_file_name, &s) == 0 + && s.st_mtime <= current_stat.st_mtime) + add_avoided_name (current_file_name); + } + skip_member (); + break; + } + + case HEADER_ZERO_BLOCK: + current_block = current_header; + found_end = 1; + break; + + case HEADER_END_OF_FILE: + found_end = 1; + 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: + abort (); + } + break; + } + + previous_status = status; + } + + reset_eof (); + time_to_start_writing = 1; + output_start = current_block->buffer; + + { + char *path; + + while (path = name_from_list (), path) + { + if (excluded_name (path)) + continue; + if (interactive_option && !confirm ("add", path)) + continue; + if (subcommand_option == CAT_SUBCOMMAND) + append_file (path); + else + dump_file (path, 1, (dev_t) 0); + } + } + + write_eot (); + close_archive (); + names_notfound (); +} |
