#!/usr/bin/perl

#- Mandrake Simple Archive Extracter/Builder.
#- Copyright (C) 2000 MandrakeSoft <fpons@mandrakesoft.com>
#-
#- 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.

#- Simple cat archive with gzip/bzip2 for perl.
#- This new version is merging of the extract_achive and build_archive.
#-
#- uncompressing sheme is:
#-         | |
#-         | |                                        | |
#-  $off1 =|*| }                                      | |
#-         |*| }                               $off2 =|+| }
#-         |*| } $siz1   =>   'gzip/bzip2 -d'   =>    |+| } $siz2  => $filename
#-         |*| }                                      |+| }
#-         |*| }                                      | |
#-         | |                                        | |
#-         | |                                        | |
#-         | |
#- where %data has the following format:
#-   { 'filename' => [ 'f', $off1, $siz1, $off2, $siz2 ] }
#- except for symbolink link where it is:
#-   { 'filename_symlink' => [ 'l', $symlink_value ] }
#- and directory where it is only
#-   { 'filename_directory' => [ 'd' ] }
#- as you can see, there is no owner, group, filemode... an extension could be
#- made with 'F' (instead of 'f'), 'L' instead of 'l' for exemple.
#- we do not need them as it is used for DrakX for fast archive extraction and
#- owner/filemode is for user running only (ie root).
#-
#- archive file contains concatenation of all bzip2'ed group of files whose
#- filenames are on input,
#- then a TOC (describing %data, concatenation of toc_line) follow and a
#- TOC_TRAILER for summary.

#+use strict qw(subs vars refs);

#- general information.
my $VERSION = "0.1";
my $default_size = 400000;
my $default_tmpdir = "/tmp";
my $default_ratio = 6;

#- used for uncompressing archive and listing.
my %toc_trailer;
my @data;
my %data;

#- used for compression, always set in main.
my $tmpz = '';

#- taken from DrakX common stuff, for conveniance and modified to match our expectation.
sub dirname { @_ == 1 or die "packdrake: usage: dirname <name>\n"; local $_ = shift; s|[^/]*/*\s*$||; s|(.)/*$|$1|; $_ || '.' }
sub basename { @_ == 1 or die "packdrake: usage: basename <name>\n"; local $_ = shift; s|/*\s*$||; s|.*/||; $_ }
sub mkdir_ {
    my $root = dirname $_[0];
    if (-e $root) {
	-d $root or die "packdrake: mkdir: error creating directory $_[0]: $root is a file and i won't delete it\n";
    } else {
	mkdir_($root);
    }
    -d $_[0] and return;
    mkdir $_[0], 0755 or die "packdrake: mkdir: error creating directory $_: $!\n";
}
sub symlink_ { mkdir_ dirname($_[1]); unlink $_[1]; symlink $_[0], $_[1] }

#- for building an archive.
sub toc_line {
    my ($file, $data) = @_;

    for ($data->[0]) {
	return(/l/ && pack("anna*", 'l', length($file), length($data->[1]), "$file$data->[1]") ||
	       /d/ && pack("ana*", 'd', length($file), $file) ||
	       /f/ && pack("anNNNNa*", 'f', length($file), $data->[1], $data->[2], $data->[3], $data->[4], $file) ||
	       die "packdrake: unknown extension $_\n");
    }
}

sub cat_compress {
    my ($compress, @filenames) = @_;
    local *F;
    open F, "| $compress >$tmpz" or die "packdrake: cannot start \"$compress\"\n";
    foreach (@filenames) {
	my ($buf, $siz, $sz);
	local *FILE;
	open FILE, $_ or die "packdrake: cannot open $_: $!\n";
	$siz = -s $_;
	while (($sz = sysread(FILE, $buf, $siz > 16384 ? 16384 : $siz))) {
	    $siz -= $sz;
	    syswrite(F, $buf);
	    last unless $siz > 0;
	}
	close FILE;
    }
    close F;
    -s $tmpz;
}

sub toc_trailer {
    my ($toc_d_count, $toc_l_count, $toc_f_count, $toc_str_size, $uncompress) = @_;

    #- 'cz[0' is toc_trailer header where 0 is version information, only 0 now.
    #- '0]cz' is toc_trailer trailer that match the corresponding header for information.
    return pack "a4NNNNa40a4", 'cz[0', $toc_d_count, $toc_l_count, $toc_f_count, $toc_str_size, $uncompress, '0]cz';
}

#- compute the closure of filename list according to symlinks or directory
#- contents inside the archive.
sub compute_closure {
    my %file;
    my @file;

    #- keep in mind when a filename already exist and remove doublons.
    @file{@_} = ();

    #- navigate through filename list to follow symlinks.
    do {
	@file = grep { !$file{$_} } keys %file;
	foreach (@file) {
	    my $file = $_;

	    #- keep in mind this one has been processed and does not need
	    #- to be examined again.
	    $file{$file} = 1;

	    exists $data{$file} or next;

	    for ($data{$file}[0]) {
		#- on symlink, try to follow it and mark %file if
		#- it is still inside the archive contents.
		/l/ && do {
		    my ($source, $target) = ($file, $data{$file}[1]);

		    $source =~ s|[^/]*$||; #- remove filename to navigate directory.
		    if ($source) {
			while ($target =~ s|^\./|| || $target =~ s|//+|/| || $target =~ s|/$|| or
			       $source and $target =~ s|^\.\./|| and $source =~ s|[^/]*/$||) {}
		    }

		    #- FALL THROUGH with new selection.
		    $file = $target =~ m|^/| ? $target : $source.$target;
		};

		#- on directory, try all files on data starting with
		#- this directory, provided they are not already taken
		#- into account.
		/[ld]/ && do {
		    @file{grep { !$file{$_} && m|^$file$| || m|^$file/| } keys %data} = ();
		    last;
		};
	    }
	}
    } while (@file > 0);

    keys %file;
}

#- degraded reading of toc at end of archive, do not check filelist.
sub read_toc_trailer {
    my ($file) = @_;
    my $toc_trailer;

    local *ARCHIVE;
    open ARCHIVE, "<$file" or die "packdrake: cannot open archive file $file\n";

    #- seek to end of file minus 64, size of trailer.
    #- read toc_trailer, check header/trailer for version 0.
    seek ARCHIVE, -64, 2;
    read ARCHIVE, $toc_trailer, 64 or die "packdrake: cannot read toc_trailer of archive file $file\n";
    @toc_trailer{qw(header toc_d_count toc_l_count toc_f_count toc_str_size uncompress trailer)} =
	unpack "a4NNNNZ40a4", $toc_trailer;
    $toc_trailer{header} eq 'cz[0' && $toc_trailer{trailer} eq '0]cz' or die "packdrake: bad toc_trailer in archive file $file\n";

    close ARCHIVE;
}

#- read toc at end of archive.
sub read_toc {
    my ($file) = @_;
    my ($toc, $toc_trailer, $toc_size);
    my @toc_str;
    my @toc_data;

    local *ARCHIVE;
    open ARCHIVE, "<$file" or die "packdrake: cannot open archive file $file\n";

    #- seek to end of file minus 64, size of trailer.
    #- read toc_trailer, check header/trailer for version 0.
    seek ARCHIVE, -64, 2;
    read ARCHIVE, $toc_trailer, 64 or die "packdrake: cannot read toc_trailer of archive file $file\n";
    @toc_trailer{qw(header toc_d_count toc_l_count toc_f_count toc_str_size uncompress trailer)} =
	unpack "a4NNNNZ40a4", $toc_trailer;
    $toc_trailer{header} eq 'cz[0' && $toc_trailer{trailer} eq '0]cz' or die "packdrake: bad toc_trailer in archive file $file\n";

    #- read toc, extract data hashes.
    $toc_size = $toc_trailer{toc_str_size} + 16*$toc_trailer{toc_f_count};
    seek ARCHIVE, -64-$toc_size, 2;

    #- read strings separated by \n, so this char cannot be inside filename, oops.
    read ARCHIVE, $toc, $toc_trailer{toc_str_size} or die "packdrake: cannot read toc of archive file $file\n";
    @toc_str = split "\n", $toc;

    #- read data for file.
    read ARCHIVE, $toc, 16*$toc_trailer{toc_f_count} or die "packdrake: cannot read toc of archive file $file\n";
    @toc_data = unpack "N". 4*$toc_trailer{toc_f_count}, $toc;

    close ARCHIVE;

    foreach (0..$toc_trailer{toc_d_count}-1) {
	my $file = $toc_str[$_];
	push @data, $file;
	$data{$file} = [ 'd' ];
    }
    foreach (0..$toc_trailer{toc_l_count}-1) {
	my ($file, $symlink) = ($toc_str[$toc_trailer{toc_d_count}+2*$_],
				$toc_str[$toc_trailer{toc_d_count}+2*$_+1]);
	push @data, $file;
	$data{$file} = [ 'l', $symlink ];
    }
    foreach (0..$toc_trailer{toc_f_count}-1) {
	my $file = $toc_str[$toc_trailer{toc_d_count}+2*$toc_trailer{toc_l_count}+$_];
	push @data, $file;
	$data{$file} = [ 'f', @toc_data[4*$_ .. 4*$_+3] ];
    }

    scalar keys %data == $toc_trailer{toc_d_count}+$toc_trailer{toc_l_count}+$toc_trailer{toc_f_count} or
	die "packdrake: mismatch count when reading toc, bad archive file $file\n";
}

sub catsksz {
    my ($input, $seek, $siz, $output) = @_;
    my ($buf, $sz);

    while (($sz = sysread($input, $buf, $seek > 65536 ? 65536 : $seek))) {
	$seek -= $sz;
	last unless $seek > 0;
    }
    while (($sz = sysread($input, $buf, $siz > 65536 ? 65536 : $siz))) {
	$siz -= $sz;
	syswrite($output, $buf);
	last unless $siz > 0;
    }
}

sub cat_archive {
    my $pid;

    foreach (@_)  {
	#- update %data according to TOC_TRAILER of each archive.
	read_toc_trailer($_);

	#- dump all the file according to 
	if (my $pid = fork()) {
	    waitpid $pid, 0;
	} else {
	    open STDIN, "<$_" or die "packdrake: unable to open archive $_\n";
	    open STDERR, ">/dev/null" or die "packdrake: unable to open archive $_\n";

	    exec split " ", $toc_trailer{uncompress};

	    die "packdrake: unable to cat the archive\n";
	}
    }
}

sub extract_archive {
    my ($archivename, $dir, @file) = @_;
    my %extract_table;

    #- update %data according to TOC of archive.
    read_toc($archivename);

    #- as a special features, if both $dir and $file are empty, list contents of archive.
    if (!$dir && !@file) {
	my $count = scalar keys %data;
	print "$count files in archive, uncompression method is \"$toc_trailer{uncompress}\"\n";
	foreach my $file (@data) {
	    for ($data{$file}[0]) {
		/l/ && do { printf "l %13c %s -> %s\n", ' ', $file, $data{$file}[1]; last; };
		/d/ && do { printf "d %13c %s\n", ' ', $file; last; };
		/f/ && do { printf "f %12d %s\n", $data{$file}[4], $file; last; };
	    }
	}
	exit 0;
    }

    #- compute closure.
    @file = compute_closure(@file);

    foreach my $file (@file) {
	#- check for presence of file, but do not abort, continue with others.
	$data{$file} or do { print STDERR "packdrake: unable to find file $file in archive $archivename\n"; next };

	my $newfile = "$dir/$file";

	print "extracting $file\n";
	for ($data{$file}[0]) {
	    /l/ && do { symlink_ $data{$file}[1], $newfile; last; };
	    /d/ && do { mkdir_ $newfile; last; };
	    /f/ && do {
		mkdir_ dirname $newfile;
		$extract_table{$data{$file}[1]} ||= [ $data{$file}[2], [] ];
		push @{$extract_table{$data{$file}[1]}[1]}, [ $newfile, $data{$file}[3], $data{$file}[4] ];
		$extract_table{$data{$file}[1]}[0] == $data{$file}[2] or die "packdrake: mismatched relocation in toc\n";
		last;
	    };
	    die "packdrake: unknown extension \"$_\" when uncompressing archive $archivename\n";
	}
    }

    #- delayed extraction is done on each block for a single  execution
    #- of uncompress executable.
    foreach (sort { $a <=> $b } keys %extract_table) {
	local *OUTPUT;
	if (open OUTPUT, "-|") {
	    #- $curr_off is used to handle the reading in a pipe and simulating
	    #- a seek on it as done by catsksz, so last file position is
	    #- last byte not read (ie last block read start + last block read size).
	    my $curr_off = 0;
	    foreach (sort { $a->[1] <=> $b->[1] } @{$extract_table{$_}[1]}) {
		my ($newfile, $off, $siz) = @$_;
		local *FILE;
		open FILE, $dir ? ">$newfile" : ">&STDOUT";
		catsksz(\*OUTPUT, $off - $curr_off, $siz, \*FILE);
		$curr_off = $off + $siz;
	    }
	} else {
	    local *BUNZIP2;
	    open BUNZIP2, "| $toc_trailer{uncompress}";
	    local *ARCHIVE;
	    open ARCHIVE, "<$archivename" or die "packdrake: cannot open archive $archivename\n";
	    catsksz(\*ARCHIVE, $_, $extract_table{$_}[0], \*BUNZIP2);
	    exit 0;
	}
    }
}

sub build_archive {
    my ($archivename, $maxsiz, $compress, $uncompress) = @_;
    my ($off1, $siz1, $off2, $siz2) = ('', '', 0, 0, 0, 0);
    my @filelist = ();
    my @data = ();
    my %data = ();

    print "choosing compression method with \"$compress\" for archive $archivename\n";

    unlink "$archivename";
    unlink $tmpz;

    foreach (<STDIN>) {
	chomp;

	my $file = $_; -e $file or die "packdrake: unable to find file $file\n";

	push @data, $file;
	#- now symbolic link and directory are supported, extension is
	#- available with the first field of $data{$file}.
	if (-l $file) {
	    $data{$file} = [ 'l', readlink $file ];
	} elsif (-d $file) {
	    $data{$file} = [ 'd' ];
	} else {
	    $siz2 = -s $file;

	    push @filelist, $file;
	    $data{$file} = [ 'f', -1, -1, $off2, $siz2 ];

	    if ($off2 + $siz2 > $maxsiz) { #- need compression.
		$siz1 = cat_compress($compress, @filelist);

		foreach (@filelist) { $data{$_} = [ 'f', $off1, $siz1, $data{$_}[3], $data{$_}[4] ] }

		system "cat $tmpz >>$archivename";
		$off1 += $siz1;
		$off2 = 0; $siz2 = 0;
		@filelist = ();
	    }
	    $off2 += $siz2;
	}
    }
    if (scalar @filelist) {
	$siz1 = cat_compress($compress, @filelist);

	foreach (@filelist) { $data{$_} = [ 'f', $off1, $siz1, $data{$_}[3], $data{$_}[4] ] }

	system "cat $tmpz >>$archivename";
	$off1 += $siz1;
	print "real archive size of $archivename is $off1\n";
    }

    #- produce a TOC directly at the end of the file, follow with
    #- a trailer with TOC summary and archive summary.
    local *OUTPUT;
    open OUTPUT, ">>$archivename";

    my ($toc_str, $toc_data) = ('', '');
    my @data_d = ();
    my @data_l = ();
    my @data_f = ();

    foreach (@data) {
	my $file = $_;
	$data{$file} or die "packdrake: internal error on $_\n";

	#- specific according to type.
	#- with this version, only f has specific data other than strings.
	for ($data{$file}[0]) {
	    /d/ && do { push @data_d, $file; last; };
	    /l/ && do { push @data_l, $file; last; };
	    /f/ && do { push @data_f, $file; $toc_data .= pack("NNNN",
							       $data{$file}[1],
							       $data{$file}[2],
							       $data{$file}[3],
							       $data{$file}[4]); last; };
	    die "packdrake: unknown extension $_\n";
	}
    }

    foreach (@data_d) { $toc_str .= $_ . "\n" }
    foreach (@data_l) { $toc_str .= $_ . "\n" . $data{$_}[1] . "\n" }
    foreach (@data_f) { $toc_str .= $_ . "\n" }

    print OUTPUT $toc_str;
    print OUTPUT $toc_data;
    print OUTPUT toc_trailer(scalar(@data_d), scalar(@data_l), scalar(@data_f),
			     length($toc_str), $uncompress);
    close OUTPUT;

    unlink $tmpz;
}

sub usage {
    die "packdrake version $VERSION
Copyright (C) 2000 MandrakeSoft.
This is free software and may be redistributed under the terms of the GNU GPL.

usage:
  --help                 - print this help message.
  --build <file>         - build archive <file> with filenames given on
                           standard input.
    -[1..9]              - select appropriate compression ratio, $default_ratio by default.
    --size <cmd>         - set maximun chunk size, $default_size by default.
    --method <cmd>       - select standard compression command method, default
                           is set according to archive filename, example is
                           /bin/gzip or /usr/bin/bzip2.
    --compress <cmd>     - select compression command.
    --uncompress <cmd>   - select uncompression command.
    --tmpdir             - select a specific tempory directory for operation,
                           default to $default_tmpdir.
  --extract <file> <dir> - extract archive <file> contents to directory <dir>,
                           specific file to extract are given on command line.
    --uncompress <cmd>   - override uncompression method in archive <file>.
  --list <file>          - list contents of archive.
  --cat <file>           - dump archive, only supported with gzip and bzip2,
                           this write the contents of all file in archive.
";
}

sub main {
    my ($file, $mode, $dir, $size, $method, $compress, $uncompress, $tmpdir, $ratio);
    my @nextargv = (\$file);
    my @list = ();

    #- some quite usefull error message.
    my $error_mode = "packdrake: choose only --build, --extract, --list or --cat\n";
    for (@_) {
	/^--help$/       and do { usage; next };
	/^--build$/      and do { $mode and die $error_mode; $mode = "build"; @nextargv = (\$file); next };
	/^--extract$/    and do { $mode and die $error_mode; $mode = "extract"; @nextargv = (\$file, \$dir); next };
	/^--list$/       and do { $mode and die $error_mode; $mode = "list"; @nextargv = (\$file); next };
	/^--cat$/        and do { $mode and die $error_mode; $mode = "cat"; @nextargv = (); next };
	/^--size$/       and do { push @nextargv, \$size; next };
	/^--method$/     and do { push @nextargv, \$method; next };
	/^--compress$/   and do { push @nextargv, \$compress; next };
	/^--uncompress$/ and do { push @nextargv, \$uncompress; next };
	/^--tmpdir$/     and do { push @nextargv, \$tmpdir; next };
	/^-(.*)$/ and do { foreach (split //, $1) {
	    /[1-9]/  and do { $ratio = $_; next };
	    /b/      and do { $mode and die $error_mode; $mode = "build"; @nextargv = (\$file); next };
	    /x/      and do { $mode and die $error_mode; $mode = "extract"; @nextargv = (\$file, \$dir); next };
	    /l/      and do { $mode and die $error_mode; $mode = "list"; @nextargv = (\$file); next };
	    /c/      and do { $mode and die $error_mode; $mode = "cat"; @nextargv = (); next };
	    /s/      and do { push @nextargv, \$size; next };
	    /m/      and do { push @nextargv, \$method; next };
	    die "packdrake: unknown option \"-$1\", check usage with --help\n"; } next };
	$mode =~ /extract|cat/ or @nextargv or die "packdrake: unknown option \"$_\", check usage with --help\n";
	my $ref = shift @nextargv; $ref ? $$ref = $_ : push @list, $_;
	$mode ||= "list";
    }

    #- examine and lauch.
    $mode =~ /cat/ or $file or die "packdrake: no archive filename given, check usage with --help\n";
    $size ||= 400000;
    $tmpdir ||= "/tmp";
    $ratio ||= 6;

    $tmpz = "$tmpdir/packdrake-tmp.$$";
    unless ($method) {
	$file =~ /\.cz$/  and $method = "gzip";
	$file =~ /\.cz2$/ and $method = "bzip2";
    }

    $compress ||= "$method -$ratio";
    $uncompress ||= "$method -d";

    for ($mode) {
	/build/   and do { build_archive($file, $size, $compress, $uncompress); last };
	/extract/ and do { extract_archive($file, $dir, @list); last };
	/list/    and do { extract_archive($file); last };
	/cat/     and do { cat_archive(@list); last };
	die "packdrake: internal error, unable to select right mode?\n";
    }
}

#- start the stuff.
main(@ARGV);