diff options
Diffstat (limited to 'delete.cc')
| -rw-r--r-- | delete.cc | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/delete.cc b/delete.cc new file mode 100644 index 0000000..6e54cf3 --- /dev/null +++ b/delete.cc @@ -0,0 +1,189 @@ +/* Tarlz - Archiver with multimember lzip compression + Copyright (C) 2013-2024 Antonio Diaz Diaz. + + 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 of the License, 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, see <http://www.gnu.org/licenses/>. +*/ + +#define _FILE_OFFSET_BITS 64 + +#include <cctype> +#include <cerrno> +#include <cstdio> +#include <stdint.h> // for lzlib.h +#include <unistd.h> +#include <lzlib.h> + +#include "tarlz.h" +#include "arg_parser.h" +#include "lzip_index.h" +#include "archive_reader.h" + + +bool safe_seek( const int fd, const long long pos ) + { + if( lseek( fd, pos, SEEK_SET ) == pos ) return true; + show_error( seek_msg, errno ); return false; + } + + +int tail_copy( const Arg_parser & parser, const Archive_descriptor & ad, + std::vector< char > & name_pending, const long long istream_pos, + const int outfd, int retval ) + { + const long long rest = ad.lzip_index.file_size() - istream_pos; + if( istream_pos > 0 && rest > 0 && + ( !safe_seek( ad.infd, istream_pos ) || + !copy_file( ad.infd, outfd, rest ) ) ) + { show_file_error( ad.namep, "Error during tail copy." ); + return retval ? retval : 1; } + const long long ostream_pos = lseek( outfd, 0, SEEK_CUR ); + if( ostream_pos < 0 ) + { show_file_error( ad.namep, seek_msg, errno ); retval = 1; } + else if( ostream_pos > 0 && ostream_pos < ad.lzip_index.file_size() ) + { + int ret; + do ret = ftruncate( outfd, ostream_pos ); + while( ret != 0 && errno == EINTR ); + if( ret != 0 || lseek( outfd, 0, SEEK_END ) != ostream_pos ) + { + show_file_error( ad.namep, "Can't truncate archive", errno ); + if( retval < 1 ) retval = 1; + } + } + + if( ( close( outfd ) | close( ad.infd ) ) != 0 && retval == 0 ) + { show_file_error( ad.namep, eclosa_msg, errno ); retval = 1; } + + if( retval == 0 ) + for( int i = 0; i < parser.arguments(); ++i ) + if( nonempty_arg( parser, i ) && name_pending[i] ) + { show_file_error( parser.argument( i ).c_str(), nfound_msg ); + retval = 1; } + return retval; + } + + +/* Deleting from a corrupt archive must not worsen the corruption. Stop and + tail-copy as soon as corruption is found. +*/ +int delete_members( const Cl_options & cl_opts ) + { + if( cl_opts.num_files <= 0 ) + { if( verbosity >= 1 ) show_error( "Nothing to delete." ); return 0; } + if( cl_opts.archive_name.empty() ) + { show_error( "Deleting from stdin not implemented yet." ); return 1; } + const Archive_descriptor ad( cl_opts.archive_name ); + if( ad.infd < 0 ) return 1; + const int outfd = open_outstream( cl_opts.archive_name, false ); + if( outfd < 0 ) { close( ad.infd ); return 1; } + + // mark member names to be deleted + std::vector< char > name_pending( cl_opts.parser.arguments(), false ); + for( int i = 0; i < cl_opts.parser.arguments(); ++i ) + if( nonempty_arg( cl_opts.parser, i ) && + !Exclude::excluded( cl_opts.parser.argument( i ).c_str() ) ) + name_pending[i] = true; + + if( ad.indexed ) // archive is a compressed regular file + return delete_members_lz( cl_opts, ad, name_pending, outfd ); + if( !ad.seekable ) + { show_file_error( ad.namep, "Archive is not seekable." ); return 1; } + if( ad.lzip_index.file_size() < 3 * header_size ) + { show_file_error( ad.namep, has_lz_ext( ad.name ) ? + posix_lz_msg : posix_msg ); return 2; } + // archive is uncompressed seekable, unless compressed corrupt + + Archive_reader ar( ad ); // serial reader + Resizable_buffer rbuf; + long long istream_pos = 0; // source of next data move + long long member_begin = 0; // first pos of current tar member + Extended extended; // metadata from extended records + int retval = 0; + bool prev_extended = false; // prev header was extended + if( !rbuf.size() ) { show_error( mem_msg ); return 1; } + + while( true ) // process one tar header per iteration + { + if( !prev_extended && ( member_begin = lseek( ad.infd, 0, SEEK_CUR ) ) < 0 ) + { show_file_error( ad.namep, seek_msg, errno ); retval = 1; break; } + Tar_header header; + if( ( retval = ar.read( header, header_size ) ) != 0 ) + { show_file_error( ad.namep, ar.e_msg(), ar.e_code() ); break; } + if( !check_ustar_chksum( header ) ) // error or EOA + { + if( block_is_zero( header, header_size ) ) // EOA + { + if( prev_extended && !cl_opts.permissive ) + { show_file_error( ad.namep, fv_msg1 ); retval = 2; } + break; + } + // posix format already checked by archive reader + show_file_error( ad.namep, bad_hdr_msg ); + retval = 2; break; + } + + const Typeflag typeflag = (Typeflag)header[typeflag_o]; + if( typeflag == tf_global ) + { + if( prev_extended && !cl_opts.permissive ) + { show_file_error( ad.namep, fv_msg2 ); retval = 2; break; } + Extended dummy; // global headers are parsed and ignored + retval = ar.parse_records( dummy, header, rbuf, gblrec_msg, true ); + if( retval ) + { show_file_error( ad.namep, ar.e_msg(), ar.e_code() ); break; } + continue; + } + if( typeflag == tf_extended ) + { + if( prev_extended && !cl_opts.permissive ) + { show_file_error( ad.namep, fv_msg3 ); retval = 2; break; } + if( ( retval = ar.parse_records( extended, header, rbuf, extrec_msg, + cl_opts.permissive ) ) != 0 ) + { show_file_error( ad.namep, ar.e_msg(), ar.e_code() ); break; } + if( !extended.crc_present() && cl_opts.missing_crc ) + { show_file_error( ad.namep, miscrc_msg ); retval = 2; break; } + prev_extended = true; continue; + } + prev_extended = false; + + extended.fill_from_ustar( header ); // copy metadata from header + + if( ( retval = ar.skip_member( extended ) ) != 0 ) + { show_file_error( ad.namep, seek_msg, errno ); break; } + + // delete tar member + if( !check_skip_filename( cl_opts, name_pending, extended.path().c_str() ) ) + { + print_removed_prefix( extended.removed_prefix ); + if( !show_member_name( extended, header, 1, rbuf ) ) + { retval = 1; break; } + const long long pos = lseek( ad.infd, 0, SEEK_CUR ); + if( pos <= 0 || pos <= member_begin || member_begin < istream_pos ) + { show_file_error( ad.namep, seek_msg, errno ); retval = 1; break; } + const long long size = member_begin - istream_pos; + if( size > 0 ) // move pending data each time a member is deleted + { + if( istream_pos == 0 ) + { if( !safe_seek( outfd, size ) ) { retval = 1; break; } } + else if( !safe_seek( ad.infd, istream_pos ) || + !copy_file( ad.infd, outfd, size ) || + !safe_seek( ad.infd, pos ) ) { retval = 1; break; } + } + istream_pos = pos; + } + extended.reset(); + } + + return tail_copy( cl_opts.parser, ad, name_pending, istream_pos, outfd, retval ); + } |