#! /usr/bin/perl -w
#
# atool - A script for managing file archives of various types.
#
# Copyright (C) 2001  Oskar Liljeblad
#
#   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, write to the Free Software
#   Foundation, Inc., 59 Temple Place, Suite 330, Boston,
#   MA  02111-1307  USA
#
# See the atool(1) manual page for usage details.
#
# This file uses tab stops with width 2.
#

use File::Basename;
use File::Spec;
use Getopt::Long;
use POSIX;
use locale;
use strict;

# Subroutine prototypes (needed for perl 5.6)
sub runcmds($$;@);                #
sub getmode();                    #
sub multiarchivecmd($$$$@);       #
sub singlearchivecmd($$$$@);      #
sub maketarcmd($$$$@);            #
sub cmdexec($@);                  #
sub parsefmt($$);                 #
sub makeoutdir();                 #
sub makeoutfile();                #
sub explain($);                   #
sub extract(@);                   #
sub shquotemeta($);               #
sub tailslash($);                 #
sub de($);                        #
sub makespec(@);                  #
sub backticks(@);                 #
sub readconfig($$);               #
sub formatext($);                 #
sub stripext($);                  #
sub findformat($$);               #
sub unlink_directory($);          #
sub find_comparable_file($);      #
sub makeabsolute($);              #
sub quote($);                     #
sub shell_execute(@);             #
sub save_outdir($);               #
sub handle_empty_add(@);          #

# Configuration options and their built-in defaults
$::cfg_args_diff            = '-ru';              # arguments to pass to diff program
$::cfg_default_verbosity    = 1;                  # default verbosity level
$::cfg_keep_compressed      = 1;                  # keep compressed file after pack/unpack
$::cfg_path_arc             = 'arc';              # arc program
$::cfg_path_arj             = 'arj';              # arj program
$::cfg_path_bzip            = 'bzip';             # bzip program
$::cfg_path_bzip2           = 'bzip2';            # bzip2 program
$::cfg_path_cat             = 'cat';              # cat program
$::cfg_path_compress        = 'compress';         # compress program
$::cfg_path_cpio            = 'cpio';             # cpio program
$::cfg_path_diff            = 'diff';             # diff program
$::cfg_path_file            = 'file';             # file program
$::cfg_path_find            = 'find';             # find program
$::cfg_path_gzip            = 'gzip';             # gzip program
$::cfg_path_jar             = 'jar';              # jar program
$::cfg_path_lha             = 'lha';              # lha program
$::cfg_path_lzop            = 'lzop';             # lzop program
$::cfg_path_nomarch         = 'nomarch';          # nomarch program
$::cfg_path_pager           = 'pager';            # pager program
$::cfg_path_rar             = 'rar';              # rar program
$::cfg_path_rpm             = 'rpm';              # rpm program
$::cfg_path_rpm2cpio        = 'rpm2cpio';         # rpm2cpio program
$::cfg_path_syscfg          = '/etc/atool.conf';  # system-wide configuration file
$::cfg_path_tar             = 'tar';              # tar program
$::cfg_path_unace           = 'unace';            # unace program
$::cfg_path_unarj           = 'unarj';            # unarj program
$::cfg_path_unrar           = 'unrar';            # unrar program
$::cfg_path_unzip           = 'unzip';            # unzip program
$::cfg_path_usercfg         = '.atoolrc';         # user configuration file
$::cfg_path_xargs           = 'xargs';            # xargs program
$::cfg_path_zip             = 'zip';              # zip program
$::cfg_show_extracted       = 1;                  # always show extracted file/directory
$::cfg_strip_unknown_ext    = 1;                  # strip unknown extensions
$::cfg_tmpdir_name          = 'Unpack-%04d';      # extraction directory name
$::cfg_use_arc_for_unpack   = 0;                  # use arc to unpack arc files?
$::cfg_use_arj_for_unpack   = 0;                  # use arj to unpack arj files?
$::cfg_use_file             = 1;                  # use file(1) for unknown extensions?
$::cfg_use_find_cpio_print0 = 1;                  # use -print0/-0 find/cpio options?
$::cfg_use_gzip_for_z       = 1;                  # use gzip to decompress .Z files?
$::cfg_use_jar              = 0;                  # use jar or zip for .jar archives?
$::cfg_use_rar_for_unpack   = 0;                  # use rar to unpack rar files?
$::cfg_use_tar_bzip2_option = 1;                  # does tar support --bzip2?
$::cfg_use_tar_z_option     = 1;                  # does tar support -z?

# Global variables
$::basename = quote(File::Basename::basename($0));
@::rmdirs = ();
$::up = File::Spec->updir();
$::cur = File::Spec->curdir();

# Parse arguments
Getopt::Long::config('bundling');
Getopt::Long::GetOptions(
    'l|list'         => \$::opt_cmd_list,
    'x|extract'      => \$::opt_cmd_extract,
    'X|extract-to=s' => \$::opt_cmd_extract_to,
    'a|add'          => \$::opt_cmd_add,
    'c|cat'          => \$::opt_cmd_cat,
    'd|diff'         => \$::opt_cmd_diff,
    'r|repack'       => \$::opt_cmd_repack,
    'q|quiet'        => sub { $::opt_verbosity--; },
    'v|verbose'      => sub { $::opt_verbosity++; },
    'V|verbosity=i'  => \$::opt_verbosity,
    'config=s'       => \$::opt_config,
    'help'           => \$::opt_cmd_help,
    'version'        => \$::opt_cmd_version,
    'F|format=s'     => \$::opt_format,
    'f|force'        => \$::opt_force,
    'p|page'         => \$::opt_use_pager,
    'e|each'         => \$::opt_each,
    'E|explain'      => \$::opt_explain,
    'S|simulate'     => \$::opt_simulate,
    'save-outdir=s'  => \$::opt_save_outdir,
    'D|subdir'       => \$::opt_extract_subdir,
    '0|null'         => \$::opt_null,
) or exit 1;

# Display --version
if ($::opt_cmd_version) {
    print
"atool 0.27.0\
Written by Oskar Liljeblad <oskar\@osk.mine.nu>.\
\
Copyright (C) 2001-2003 Oskar Liljeblad.\
This is free software; see the source for copying conditions.  There is NO\
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n";
    exit;
}

# Display --help
if ($::opt_cmd_help) {
    print
"Usage: atool [OPTION]... ARCHIVE [FILE]...\
       atool -e [OPTION]... [ARCHIVE]...
Managing file archives of various types.\
\
Commands:\
  -l, --list              list files in archive (als)\
  -x, --extract           extract files from archive (aunpack)\
  -X, --extract-to=PATH   extract archive to specified directory\
  -a, --add               create archive (apack)\
  -c, --cat               extract file to standard out (acat)\
  -d, --diff              generate a diff between two archives (adiff)\
      --help              display this help and exit\
      --version           output version information and exit\
\
Options:\
  -e, --each              execute command above for each file specified
  -F, --format=EXT        override archive format (see below)\
  -D, --subdir            always create subdirectory when extracting\
  -f, --force             allow overwriting of local files\
  -q, --quiet             decrease verbosity level by one\
  -v, --verbose           increase verbosity level by one\
  -V, --verbosity=LEVEL   specify verbosity (0, 1 or 2)\
  -p, --page              send output through pager\
  -0, --null              filenames from standard in are null-byte separated\
  -E, --explain           explain what is being done by atool\
  -S, --simulate          simulation mode - no filesystem changes are made\
      --config=FILE       load configuration defaults from file\
\
Archive format (for --format) may be specified either as a\
file extension (\"tar.gz\") or as \"tar+gzip\".\
\
Report bugs to Oskar Liljeblad <oskar\@osk.mine.nu>.\
";
    exit;
}

# Read configuration files
if (defined $::opt_config) {
    readconfig($::opt_config, 0);
} else {
    readconfig($::cfg_path_syscfg, 1);
    if ($::cfg_path_usercfg !~ /^\//) {
        readconfig(File::Spec->catfile($ENV{HOME}, $::cfg_path_usercfg), 1);
    } else {
        readconfig($::cfg_path_usercfg, 1);
    }
}

# Verify option integrity
$::opt_verbosity += $::cfg_default_verbosity;
if ($::opt_explain && $::opt_simulate) {
    die "$::basename: --explain and --simulate options are mutually exclusive\n";    #OK
}

my $mode = getmode();

if (defined $::opt_save_outdir && $mode eq 'extract-to') {
    die "$::basename: --save-outdir cannot be used in extract-to mode\n";
}
if ($::opt_extract_subdir && $mode ne 'extract') {
    die "$::basename: --subdir can only be used in extract mode\n";
}

if ($mode eq 'diff') {
    die "$::basename: missing archive argument\n" if (@ARGV < 2);    #OK
    my $use_pager = $::opt_use_pager;
    $::opt_verbosity--;
    $::opt_use_pager = 0;

    my $outfile1 = makeoutdir() || exit 1;
    my $outfile2 = makeoutdir() || exit 1;
    $::opt_cmd_extract_to = $outfile1;
    exit 1 if (!runcmds('extract-to', $ARGV[0]));
    $::opt_cmd_extract_to = $outfile2;
    exit 1 if (!runcmds('extract-to', $ARGV[1]));

    my $match1 = find_comparable_file($outfile1);
    my $match2 = find_comparable_file($outfile2);

    my @cmd = ($::cfg_path_diff, split(/ /, $::cfg_args_diff), $match1, $match2);
    push @cmd, ['|'], get_pager_program() if $use_pager;
    my $allok = cmdexec(1, @cmd);

    foreach my $file ($outfile1,$outfile2) {
        if (-e $file && -d $file) {
        #if (-e $file) {
            #print "$::basename: remove `$file'? ";
            #select((select(STDOUT), $| = 1)[0]);
            #my $line = <STDIN>;
            #if (defined $line && $line =~ /^y/) {
                #if (-d $file) {
                    unlink_directory($file);
                #} else {
                    #unlink $file;
                #}
            #}
        }
    }

    exit ($allok ? 0 : 1);
}
elsif ($mode eq 'repack') {
    #FIXME: what if --each!
    die "$::basename: missing archive arguments\n" if (@ARGV < 1);    #OK
    die "$::basename: missing archive argument\n" if (@ARGV < 2);        #OK
    die "$::basename: cannot repack to same archive\n"
        if ($ARGV[0] eq $ARGV[1]
                || File::Spec->canonpath($ARGV[0]) eq File::Spec->canonpath($ARGV[1]));
    die "$::basename: ".quote($ARGV[1]).": destination file exists\n" if -e $ARGV[1];

    my $outdir = makeoutdir() || exit 1;
    $::opt_cmd_extract_to = $outdir;
    exit 1 if (!runcmds('extract-to', $ARGV[0]));                                                                        #OK?????
    my $newarchive = File::Spec->catdir($::up, $ARGV[1]);
    chdir($outdir) || die "$::basename: ".quote($outdir).": cannot change to - $!\n";            #OK?????
    exit 1 if (!runcmds('add', $newarchive, $::cur));
    chdir($::up) || die "$::basename: ".$::up.": cannot change to - $!\n";    #OK?????
    unlink_directory($outdir);
}
elsif ($::opt_each) {
    my $allok = 1;
    if ($mode eq 'cat') {
        die "$::basename: --each can not be used with cat or add command\n";    #OK
    }
    if ($mode eq 'add') {
        if (!defined $::opt_format) {
            die "$::basename: specify a format with -F when using --each in add mode\n";
        }
        my $format = findformat($::opt_format, 1);
        for (my $c = 0; $c < @ARGV; $c++) {
            my $archive = File::Spec->canonpath($ARGV[$c]) . formatext($format);
            warn quote($archive).":\n" if $::opt_verbosity > 1;
            runcmds($mode, $archive, $ARGV[$c]) or $allok = 0;
        }
    } else {
        for (my $c = 0; $c < @ARGV; $c++) {
            warn quote($ARGV[$c]).":\n" if $::opt_verbosity > 1;
            runcmds($mode, $ARGV[$c]) or $allok = 0;
        }
    }
    exit ($allok ? 0 : 1);
}
else {
    die "$::basename: missing archive argument\n" if (@ARGV == 0);    #OK
    runcmds($mode, shift @ARGV, @ARGV) || exit 1;
}

# runcmds(mode, archive, args)
# Execute an atool command. This is where it all happens.
# If mode is 'extract', returns the directory (or only file)
# which was extracted.
sub runcmds($$;@) {
    my ($mode, $archive, @args) = @_;

    my $format;
    if (defined $::opt_format) {
        $format = findformat($::opt_format, 1);
    } else {
        $format = findformat($archive, 0);
    }
    return undef if !defined $format;

    my @cmd;
    my $outdir;
    if ($format eq 'tar+bzip2') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        if ($::cfg_use_tar_bzip2_option) {
            push @cmd, maketarcmd($archive, $outdir, $mode, 'f', '--bzip2'), @args;
        } else {
            push @cmd, $::cfg_path_bzip2, '-cd', $archive, ['|'] if $mode ne 'add';
            push @cmd, maketarcmd(undef, $outdir, $mode, ''), @args;
            push @cmd, ['|'], $::cfg_path_bzip2, ['>'], $archive if $mode eq 'add';
        }
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 1, 0, \@args, @cmd);
    }
    elsif ($format eq 'tar+gzip') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        if ($::cfg_use_tar_z_option) {
            push @cmd, maketarcmd($archive, $outdir, $mode, 'zf'), @args;
        } else {
            push @cmd, $::cfg_path_gzip, '-cd', $archive, ['|'] if $mode ne 'add';
            push @cmd, maketarcmd(undef, $outdir, $mode, ''), @args;
            push @cmd, ['|'], $::cfg_path_gzip, ['>'], $archive if $mode eq 'add';
        }
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 1, 0, \@args, @cmd);
    }
    elsif ($format eq 'tar+bzip') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        push @cmd, $::cfg_path_bzip, '-cd', $archive, ['|']    if $mode ne 'add';
        push @cmd, maketarcmd(undef, $outdir, $mode, ''), @args;
        push @cmd, ['|'], $::cfg_path_bzip, ['>'], $archive if $mode eq 'add';
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 1, 0, \@args, @cmd);
    }
    elsif ($format eq 'tar+compress') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        if ($::cfg_use_gzip_for_z) {
            push @cmd, $::cfg_path_gzip, '-cd', $archive, ['|']    if $mode ne 'add';
        } else {
            push @cmd, $::cfg_path_compress, '-cd', $archive, ['|']    if $mode ne 'add';
        }
        push @cmd, maketarcmd(undef, $outdir, $mode, ''), @args;
        push @cmd, ['|'], $::cfg_path_compress, ['>'], $archive if $mode eq 'add';
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 1, 0, \@args, @cmd);
    }
    elsif ($format eq 'tar+lzop') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        push @cmd, $::cfg_path_lzop, '-Ucd', $archive, ['|']    if $mode ne 'add';
        push @cmd, maketarcmd(undef, $outdir, $mode, ''), @args;
        push @cmd, ['|'], $::cfg_path_lzop, ['>'], $archive if $mode eq 'add';
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 1, 0, \@args, @cmd);
    }
    elsif ($format eq 'tar') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        push @cmd, maketarcmd($archive, $outdir, $mode, 'f'), @args;
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 1, 0, \@args, @cmd);
    }
    elsif ($format eq 'jar' && $::cfg_use_jar) {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        my $opts = '';
        if ($mode eq 'add') {
            warn "$::basename: ".quote($archive).": $mode command not supported for $format archives\n";
            return undef;
        }
        $opts .= 'v' if $::opt_verbosity >= 1;
        push @cmd, $::cfg_path_jar;
        push @cmd, "x$opts", '-C', $outdir if $mode eq 'extract';
        push @cmd, "x$opts", '-C', $::opt_cmd_extract_to if $mode eq 'extract-to';
        push @cmd, "t$opts" if $mode eq 'list';
        push @cmd, "c$opts" if $mode eq 'add';
        push @cmd, $archive, @args;
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 1, 0, \@args, @cmd);
    }
    elsif ($format eq 'jar' || $format eq 'zip') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        if ($mode eq 'add') {
            push @cmd, $::cfg_path_zip, '-r';
        } else {
            push @cmd, $::cfg_path_unzip;
            push @cmd, '-p' if $mode eq 'cat';
            push @cmd, '-l' if $mode eq 'list';
            push @cmd, '-d', $outdir if $mode eq 'extract';
            push @cmd, '-d', $::opt_cmd_extract_to if $mode eq 'extract-to';
        }
        push @cmd, '-v' if $::opt_verbosity > 1;
        push @cmd, '-qq' if $::opt_verbosity < 0;
        push @cmd, '-q' if $::opt_verbosity == 0;
        push @cmd, $archive, @args;
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 0, 0, \@args, @cmd);
    }
    elsif ($format eq 'rar') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        if ($mode eq 'add' || $::cfg_use_rar_for_unpack) {
            push @cmd, $::cfg_path_rar;
        } else {
            push @cmd, $::cfg_path_unrar;
        }
        push @cmd, 'a' if $mode eq 'add';
        push @cmd, 'vt' if $mode eq 'list' && $::opt_verbosity >= 3;
        push @cmd, 'v' if $mode eq 'list' && $::opt_verbosity == 2;
        push @cmd, 'l' if $mode eq 'list' && $::opt_verbosity <= 1;
        push @cmd, 'x' if ($mode eq 'extract' || $mode eq 'extract-to');
        push @cmd, '-ierr', 'p' if $mode eq 'cat';
        push @cmd, '-r' if ($mode eq 'add');
        push @cmd, $archive, @args;
        push @cmd, tailslash($outdir) if $mode eq 'extract';
        push @cmd, tailslash($::opt_cmd_extract_to) if $mode eq 'extract-to';
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 0, 0, \@args, @cmd);
    }
    elsif ($format eq 'lha') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        push @cmd, $::cfg_path_lha;
        push @cmd, 'a' if $mode eq 'add';
        push @cmd, 'v' if $mode eq 'list' && $::opt_verbosity >= 3;
        push @cmd, 'l' if $mode eq 'list' && $::opt_verbosity == 2;
        push @cmd, 'lq' if $mode eq 'list' && $::opt_verbosity <= 1;
        push @cmd, 'x' if ($mode eq 'extract' || $mode eq 'extract-to');
        push @cmd, 'p' if $mode eq 'cat';
        push @cmd, $archive, @args;
        push @cmd, tailslash($outdir) if $mode eq 'extract';
        push @cmd, tailslash($::opt_cmd_extract_to) if $mode eq 'extract-to';
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 0, 0, \@args, @cmd);
    }
    elsif ($format eq 'ace') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        push @cmd, $::cfg_path_unace;
        if ($mode eq 'add' || $mode eq 'cat') {
            warn "$::basename: ".quote($archive).": $mode command not supported for $format archives\n";
            return undef;
        }
        push @cmd, 'v', '-c' if $mode eq 'list' && $::opt_verbosity >= 3;
        push @cmd, 'v' if $mode eq 'list' && $::opt_verbosity == 2;
        push @cmd, 'l' if $mode eq 'list' && $::opt_verbosity <= 1;
        push @cmd, 'x' if ($mode eq 'extract' || $mode eq 'extract-to');
        push @cmd, $archive, @args;
        push @cmd, tailslash($outdir) if $mode eq 'extract';
        push @cmd, tailslash($::opt_cmd_extract_to) if $mode eq 'extract-to';
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 0, 0, \@args, @cmd);
    }
    elsif ($format eq 'arj') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        if ($mode eq 'cat') {
            warn "$::basename: ".quote($archive).": $mode command not supported for $format archives\n";
            return undef;
        }
        if ($mode eq 'add' || $::cfg_use_arj_for_unpack) {
            push @cmd, $::cfg_path_arj;
            push @cmd, 'a' if $mode eq 'add';
            push @cmd, 'v' if $mode eq 'list' && $::opt_verbosity == 2;
            push @cmd, 'l' if $mode eq 'list' && $::opt_verbosity <= 1;
            push @cmd, 'x' if ($mode eq 'extract' || $mode eq 'extract-to');
            push @cmd, $archive, @args;
            push @cmd, tailslash($outdir) if $mode eq 'extract';
            push @cmd, tailslash($::opt_cmd_extract_to) if $mode eq 'extract-to';
            @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
            return multiarchivecmd($archive, $outdir, $mode, 0, 0, \@args, @cmd);
        } else {
            push @cmd, $::cfg_path_unarj;
            # XXX: cat mode might work for arj archives, but it extract to stderr!
            push @cmd, 'v' if $mode eq 'list' && $::opt_verbosity == 2;
            push @cmd, 'l' if $mode eq 'list' && $::opt_verbosity <= 1;
            push @cmd, 'x' if ($mode eq 'extract' || $mode eq 'extract-to');
            push @cmd, $archive if ($mode ne 'extract' && $mode ne 'extract-to');;
            # we call makeabsolute here because needcwd=1 to the multiarchivecmd call
            push @cmd, makeabsolute($archive) if ($mode eq 'extract' || $mode eq 'extract-to');
            push @cmd, @args;
            @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
            return multiarchivecmd($archive, $outdir, $mode, 0, 1, \@args, @cmd);
        }
    }
    elsif ($format eq 'arc') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        if ($mode eq 'add' || $::cfg_use_arc_for_unpack) {
            push @cmd, $::cfg_path_arc;
            push @cmd, 'a' if $mode eq 'add';
            push @cmd, 'v' if $mode eq 'list' && $::opt_verbosity >= 3;
            push @cmd, 'l' if $mode eq 'list' && $::opt_verbosity == 2;
            push @cmd, 'ln' if $mode eq 'list' && $::opt_verbosity <= 1;
            push @cmd, 'x' if ($mode eq 'extract' || $mode eq 'extract-to');
            push @cmd, 'p' if $mode eq 'cat';
        } else {
            push @cmd, $::cfg_path_nomarch;
            push @cmd, '-lvU' if $mode eq 'list' && $::opt_verbosity >= 2;
            push @cmd, '-lU' if $mode eq 'list' && $::opt_verbosity <= 1;
            push @cmd, '-p' if $mode eq 'cat';
        }
        push @cmd, $archive if ($mode ne 'extract' && $mode ne 'extract-to');
        # we call makeabsolute here because needcwd=1 to the multiarchivecmd call
        push @cmd, makeabsolute($archive) if ($mode eq 'extract' || $mode eq 'extract-to');
        push @cmd, @args;
        @cmd = handle_empty_add(@cmd) if ($mode eq 'add' && @args == 0);
        return multiarchivecmd($archive, $outdir, $mode, 0, 1, \@args, @cmd);
    }
    elsif ($format eq 'rpm') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        if ($mode eq 'list') {
            push @cmd, $::cfg_path_rpm;
            push @cmd, '-qlp' if $mode eq 'list';
            push @cmd, '-v' if $::opt_verbosity >= 1;
            push @cmd, $archive, @args;
            return multiarchivecmd($archive, $outdir, $mode, 0, 0, \@args, @cmd);
        }
        elsif ($mode eq 'extract' || $mode eq 'extract-to') {
            push @cmd, $::cfg_path_rpm2cpio;
            push @cmd, makeabsolute($archive);
            push @cmd, ['|'];
            push @cmd, $::cfg_path_cpio, '-imd', '--quiet', @args;
            return multiarchivecmd($archive, $outdir, $mode, 0, 1, \@args, @cmd);
        }
        else { # add and cat
            # FIXME: I guess cat could work too, but it would require that we
          # extracted to a temporary dir, read and printed it, then removed it.
            warn "$::basename: ".quote($archive).": $mode command not supported for $format archives\n";
            return undef;
        }
    }
    elsif ($format eq 'cpio') {
        return undef if ($mode eq 'extract' && !defined ($outdir = makeoutdir()));
        if ($mode eq 'list') {
            push @cmd, $::cfg_path_cat, $archive, ['|'];
            push @cmd, $::cfg_path_cpio, '-t';
            push @cmd, '-v' if $::opt_verbosity >= 1;
            return multiarchivecmd($archive, $outdir, $mode, 0, 0, \@args, @cmd);
        }
        elsif ($mode eq 'extract' || $mode eq 'extract-to') {
            push @cmd, $::cfg_path_cat, makeabsolute($archive), ['|'];
            push @cmd, $::cfg_path_cpio, '-i';
            push @cmd, '-v' if $::opt_verbosity >= 1;
            return multiarchivecmd($archive, $outdir, $mode, 0, 1, \@args, @cmd);
        }
        elsif ($mode eq 'add') {
            if (@args == 0) {
                push @cmd, $::cfg_path_cpio;
                push @cmd, '-0' if $::opt_null;
                push @cmd, '-o';
                push @cmd, '-v' if $::opt_verbosity >= 1;
                push @cmd, ['>'], $archive;
            } else {
                push @cmd, $::cfg_path_find, @args;
                push @cmd, '-print0' if $::cfg_use_find_cpio_print0;
                push @cmd, ['|'], $::cfg_path_cpio;
                push @cmd, '-0' if $::cfg_use_find_cpio_print0;
                push @cmd, '-o';
                push @cmd, '-v' if $::opt_verbosity >= 1;
                push @cmd, ['>'], $archive;
            }
            return multiarchivecmd($archive, $outdir, $mode, 1, 1, \@args, @cmd);
        }
        else { # cat
            warn "$::basename: ".quote($archive).": $mode command not supported for $format archives\n";
            return undef;
        }
    }
    elsif ($format eq 'bzip2') {
        return singlearchivecmd($archive, $::cfg_path_bzip2, $format, $mode, @args);
    }
    elsif ($format eq 'bzip') {
        return singlearchivecmd($archive, $::cfg_path_bzip, $format, $mode, @args);
    }
    elsif ($format eq 'gzip') {
        return singlearchivecmd($archive, $::cfg_path_gzip, $format, $mode, @args);
    }
    elsif ($format eq 'compress') {
        if ($::cfg_use_gzip_for_z && $mode ne 'add') {
            return singlearchivecmd($archive, $::cfg_path_gzip, $format, $mode, @args);
        } else {
            return singlearchivecmd($archive, $::cfg_path_compress, $format, $mode, @args);
        }
    }
    elsif ($format eq 'lzop') {
        return singlearchivecmd($archive, $::cfg_path_lzop, $format, $mode, '-U', @args);
    }

    return undef;
}

# de(value):
# Return 1 if value defined and is non-zero, 0 otherwise.
sub de($) {
    my ($value) = @_;
    return defined $value && $value ? 1 : 0;
}

# getmode()
# Identify the execution mode, and return it.
# Possible modes are 'cat', 'extract', 'list', 'add' or 'extract-to'.
sub getmode() {
    my $mode;
    if (de($::opt_cmd_list)
            + de($::opt_cmd_cat)
            + de($::opt_cmd_extract)
            + de($::opt_cmd_add) 
            + de($::opt_cmd_extract_to)
            + de($::opt_cmd_diff)
            + de($::opt_cmd_repack) > 1) {
        die "$::basename: only one command may be specified\n"; #OK
    }
    $mode = 'cat'           if ($::basename eq 'acat');
    $mode = 'extract'       if ($::basename eq 'aunpack');
    $mode = 'list'          if ($::basename eq 'als');
    $mode = 'add'           if ($::basename eq 'apack');
    $mode = 'diff'          if ($::basename eq 'adiff');
    $mode = 'repack'        if ($::basename eq 'arepack');
    $mode = 'add'                if ($::opt_cmd_add);
    $mode = 'cat'                if ($::opt_cmd_cat);
    $mode = 'list'                if ($::opt_cmd_list);
    $mode = 'extract'          if ($::opt_cmd_extract);
    $mode = 'extract-to'    if ($::opt_cmd_extract_to);
    $mode = 'diff'          if ($::opt_cmd_diff);
    $mode = 'repack'        if ($::opt_cmd_repack);
    if (!defined $mode) {
        die "$::basename: don't know what to do - no command specified\n"; #OK
    }
    return $mode;
}

# singlearchivecmd(archive, command, format, mode, args)
# Execute a command for single-file archives.
# The command parameter specifies what command to execute.
# If mode is 'extract-to', returns the directory (or only file)
# which was extracted.
sub singlearchivecmd($$$$@) {
    my ($archive, $cmd, $format, $mode, @args) = @_;

    if ($mode eq 'add' && @ARGV > 1) {
        warn "$::basename: cannot add more than one file with this format\n";
        return;
    }
    if ($mode eq 'add' && !$::opt_force && (-e $archive || -l $archive)) {
        warn "$::basename: ".quote($archive).": refusing to overwrite existing file\n";
        return;
    }

    my $outfile;
    if ($mode eq 'extract-to') {
        $outfile = $::opt_cmd_extract_to;        # undef if not extract-to
        if (-d $outfile) {
            my $base = File::Basename::basename($archive);
            $outfile = File::Spec->catfile($outfile, stripext($base));
        }
    } elsif ($mode eq 'extract') {
        $outfile = stripext($archive);
    }

    if ($mode eq 'list') {
        warn "$::basename: ".quote($archive).": $mode command not supported for $format archives\n";
        return;
    }
    if ($mode eq 'add' && !$::cfg_keep_compressed && stripext($archive) ne $args[0]) {
        warn "$::basename: ".quote($archive).": cannot create a $format archive with this name (use -X)\n";
        return;
    }

    if ($mode eq 'extract' && -e $outfile) {
        $outfile = makeoutfile();
    }

    my @cmd;
    push @cmd, $cmd;
    push @cmd, '-v'                       if $::opt_verbosity > 1;
    if ($::cfg_keep_compressed) {
        if ($mode eq 'add') {
            push @cmd, '-c', @args, ['>'], $archive;
        } elsif ($mode eq 'cat') {
            push @cmd, '-c', '-d', $archive, @args;
        } elsif ($mode eq 'extract' || $mode eq 'extract-to') {
            push @cmd, '-c', '-d', $archive, @args, ['>'], $outfile;
        }
    } else {
        if ($mode eq 'add') {
            push @cmd, @args;
        } elsif ($mode eq 'cat') {
            push @cmd, '-c', '-d', $archive, @args;
        } elsif ($mode eq 'extract') {
            push @cmd, '-d', $archive, @args;
        } elsif ($mode eq 'extract-to') {
            push @cmd, '-c', '-d', $archive, @args, ['>'], $outfile;
        }
    }
    push @cmd, ['|'], get_pager_program() if $::opt_use_pager;
    cmdexec(0, @cmd) || return;

    if (($mode eq 'extract' || $::cfg_show_extracted) && !$::opt_simulate) {
        my $archivebase = File::Basename::basename($archive);
        warn quote($archivebase).": extracted to `".quote($outfile)."'\n";
    }

    return $outfile;
}

# maketarcmd(opts):
# Create (partial) command line arguments for a tar command.
# The parameter opts specifies additional arguments to add.
sub maketarcmd($$$$@) {
    my ($archive, $outdir, $mode, $opts, @rest) = @_;
    $opts .= 'v' if $::opt_verbosity >= 1;
    my @cmd = ($::cfg_path_tar);
    push @cmd, "xO$opts" if $mode eq 'cat';
    push @cmd, "x$opts" if ($mode eq 'extract' || $mode eq 'extract-to');
    push @cmd, "t$opts" if $mode eq 'list';
    push @cmd, "c$opts" if $mode eq 'add';
    push @cmd, $archive if defined $archive;
    push @cmd, '-C', $outdir if $mode eq 'extract';
    push @cmd, '-C', $::opt_cmd_extract_to if $mode eq 'extract-to';
    push @cmd, @rest;
    return @cmd;
}

# cmdexec(ignore_return, cmdspec)
# Execute a command specification.
# The cmdspec parameter is a list of string arguments building
# the command line. If there's a list reference instead of a
# string, it is a shell meta character/string which shouldn't
# be quoted.
sub cmdexec($@) {
    my ($ignret, @cmd) = @_;
    
    if ($::opt_explain || $::opt_simulate) {
        my $spec = join(' ', map { ref $_ ? @{$_} : shquotemeta $_ } @cmd);
        explain quote($spec)."\n";
        return 1 if ($::opt_simulate);
    }

    my $cmds = makespec(@cmd);
    if (!shell_execute(@cmd)) {
        warn "$::basename: ".quote($cmds).": cannot execute - $::errmsg\n";
        return 0;
    }

    if ($? & 0xFF != 0) {
        warn "$::basename: ".quote($cmds).": abnormal exit (exit code $?)\n";
        return 0;
    }
    
    if (!$ignret && $? >> 8 != 0) {
        warn "$::basename: ".quote($cmds).": non-zero return-code\n";
        return 0;
    }

    return 1;
}

# makespec(@)
# Make a command specification when printing errors.
sub makespec(@) {
    my (@cmd) = @_;
    my $spec = $cmd[0].' ..';
    my $lastref = 0;
    foreach (@cmd, '') {
        if ($lastref) {
            $spec .= " | $_ ..";
            $lastref = 0;
        }
        $lastref = 1 if (ref);
    }
    return $spec;
}

# makeoutfile()
# Make a unique output file for extraction command.
sub makeoutfile() {
    my $file;
    do {
        $file = sprintf $::cfg_tmpdir_name, int rand 10000;
    } while (-e $file);
    return $file;
}

# makeoutdir()
# Make a temporary (unique) output directory for extraction command.
sub makeoutdir() {
    my $dir;
    do {
        $dir = sprintf $::cfg_tmpdir_name, int rand 10000;
    } while (-e $dir);

    if (!$::opt_simulate) {
        if (!mkdir($dir, 0700)) {
            warn "$::basename: ".quote($dir).": cannot create directory - $!\n";
            return undef;
        }
        push @::rmdirs, $dir;
    }
    return $dir;
}

# explain($)
# Print on screen if $::opt_explain is true.
sub explain($) {
    my ($msg) = @_;
    print STDERR $msg if ($::opt_explain || $::opt_simulate);
}

# tailslash($)
# If specified filename does not end with a slash,
# add one and return the new filename.
sub tailslash($) {
    my ($file) = @_;
    return ($file =~ /\/$/ ? $file : "$file/");
}

# shquotemeta($)
# A more sophisticated quotemeta for bourne shells.
# (This should be used for printing only.)
sub shquotemeta($) {
    my ($str) = @_;
    $str =~ s/([^A-Za-z0-9_.+,\/:=@%^-])/\\$1/g;
    return $str;
}

# multiarchivecmd(archive, outdir, mode, create, argref, cmdspec)
# Execute a command for multi-file archives.
# The `create' argument controls whether the archive
# will be created (1) or just added to (0) if mode is "add".
# If mode is 'extract', returns the directory (or only file)
# which was extracted.
# If needcwd is true, the outdir must be changed to.
sub multiarchivecmd($$$$@) {
    my ($archive, $outdir, $mode, $create, $needcwd, $argref, @cmd) = @_;
    my @args = @{$argref};

    if ($mode eq 'cat' && @args == 0) {
        die "$::basename: missing file argument\n";    #OK
    }

    if ($mode eq 'add' && $create && !$::opt_force && (-e $archive || -l $archive)) {
        warn "$::basename: ".quote($archive).": refusing to overwrite existing file\n";
        return undef;
    }

    push @cmd, ['|'], get_pager_program() if $::opt_use_pager;

    my $olddir = undef;
    if ($needcwd && !$::opt_simulate) {
        $olddir = getcwd();
        if ($mode eq 'extract' && !chdir($outdir)) {
            warn "$::basename: ".quote($outdir).": cannot change to - $!\n";
            return undef;
        }
        if ($mode eq 'extract-to' && !chdir($::opt_cmd_extract_to)) {
            warn "$::basename: ".quote($::opt_cmd_extract_to).": cannot change to - $!\n";
            return undef;
        }
    }

    if ($mode ne 'extract') {
        cmdexec(0, @cmd) || return undef;
        if (defined $olddir && !chdir($olddir)) {
            warn "$::basename: ".quote($olddir).": cannot change to - $!\n";
            return undef;
        }
        # XXX: can't save outdir with extract-to.
        return 1;
    }

    if (!cmdexec(0, @cmd)) {
        if (defined $olddir && !chdir($olddir)) {
            warn "$::basename: ".quote($olddir).": cannot change to - $!\n";
        }
         return undef;
    }

    return undef if $::opt_simulate;

    if (defined $olddir && !chdir($olddir)) {
        warn "$::basename: ".quote($olddir).": cannot change to - $!\n";
        return undef;
    }

    if (!opendir(DIR, $outdir)) {
        warn "$::basename: ".quote($outdir).": cannot list - $!\n";
        return undef;
    }
    my @files = grep !/^\.\.?$/, readdir DIR;
    closedir DIR;

    my $archivebase = File::Basename::basename($archive);
    my $reason;
    my $adddir = 0;
    if (@files == 0) {
        warn quote($archivebase).": archive is empty\n";
        rmdir $outdir;
        return undef;
    } elsif ($::opt_extract_subdir) {
        $reason = 'forced';
    } elsif (@files == 1) {
        my $fromfile = File::Spec->catfile($outdir, $files[0]);
	my $tofile = $files[0];

	unless ($::opt_force) {
	    # Find a filename to unpack to that doesn't exist
	    my $suffix = 1;
	    my $try = $tofile;
	    $try = "$tofile." . $suffix++ until !-l $try && !-e _;
	    # We assume it will find a suitable filename eventually...
	    $tofile = $try;
	}
	
	# If the file is a directory, it can only be moved if writable
	my $oldmode = undef;
	if (!-l $fromfile && -d $fromfile) {
	    my @statinfo = stat($fromfile);
	    if (!@statinfo) {
		warn quote($fromfile).": cannot get file info - $!\n";
		return undef;
	    }
	    $oldmode = $statinfo[2];
	    if (!chmod(0700, $fromfile)) {
		warn quote($fromfile).": cannot change mode - $!\n";
		return undef;
	    }
	}
	
	if (!rename $fromfile, $tofile) {
	    warn quote($fromfile).": cannot rename - $!\n";
	    return undef;
	}
	rmdir $outdir;
	
	# If we changed mode previously, restore that mode now
	if (defined $oldmode) {
	    if (!chmod($oldmode, $tofile)) {
		warn quote($tofile).": cannot change mode - $!\n";
		return undef;
	    }
	}
	
	if ($::cfg_show_extracted) {
	    my $file = ($tofile =~ /\// ? dirname($tofile) : $tofile);
	    warn quote($archivebase).": extracted to `".quote($file)."'\n" ;
	}
	
	save_outdir($tofile);
	return $tofile;
    }
    else {
	$reason = 'multiple files in root';
    }

my $localoutdir = stripext($archivebase);
if (!-e $localoutdir) {
    if (!rename $outdir, $localoutdir) {
	warn quote($outdir).": cannot rename - $!\n";
	return undef;
    }
    $outdir = $localoutdir;
}

warn quote($archivebase).": extracted to `".quote($outdir)."' ($reason)\n";
save_outdir($adddir ? File::Spec->catfile($outdir, $files[0]) : $outdir);
    return $outdir;
}

# stripext(file)
# Strip extension from the specified file.
sub stripext($) {
    my ($file) = @_;
    return $file if ($file =~ s/(\.tar\.bz2|\.tbz2)$//);
    return $file if ($file =~ s/(\.tar\.bz|\.tbz)$//);
    return $file if ($file =~ s/(\.tar\.gz|\.tgz)$//);
    return $file if ($file =~ s/(\.tar\.Z|\.tZ)$//);
    return $file if ($file =~ s/\.tar$//);
    return $file if ($file =~ s/\.bz2$//);
    return $file if ($file =~ s/\.bz$//);
    return $file if ($file =~ s/\.gz$//);
    return $file if ($file =~ s/\.zip$//);
    return $file if ($file =~ s/\.jar$//);
    return $file if ($file =~ s/\.war$//);
    return $file if ($file =~ s/\.Z$//);
    return $file if ($file =~ s/\.rar$//);
    return $file if ($file =~ s/\.(lha|lzh)$//);
    return $file if ($file =~ s/\.ace$//);
    return $file if ($file =~ s/\.arj$//);
    return $file if ($file =~ s/\.rpm$//);
    return $file if ($file =~ s/\.cpio$//);
    return $file if ($::cfg_strip_unknown_ext && $file =~ s/\.[^.]+$//);
    return $file;
}

# formatext(format)
# Return the usual extension for the specified file format
sub formatext($) {
    my ($format) = @_;
    return '.tar.lzo'  if $format eq 'tar+lzop';
    return '.tar.bz2'  if $format eq 'tar+bzip2';
    return '.tar.bz'   if $format eq 'tar+bzip';
    return '.tar.gz'   if $format eq 'tar+gzip';
    return '.tar.Z'    if $format eq 'tar+compress';
    return '.tar'      if $format eq 'tar';
    return '.bz2'      if $format eq 'bzip2';
    return '.bz'       if $format eq 'bzip';
    return '.gz'       if $format eq 'gzip';
    return '.lzo'      if $format eq 'lzop';
    return '.zip'      if $format eq 'zip';
    return '.jar'      if $format eq 'jar';
    return '.Z'        if $format eq 'compress';
    return '.rar'      if $format eq 'rar';
    return '.ace'      if $format eq 'ace';
    return '.arj'      if $format eq 'arj';
    return '.lha'      if $format eq 'lha';
    return '.rpm'      if $format eq 'rpm';
    return '.cpio'     if $format eq 'cpio';
    die "$::basename: ".quote($format).": don't know file extension for format\n";
}

# findformat(spec, manual)
# Figure out format from specified file/string.
# If manual is 0, spec is a filename, otherwise
# it is a format description string.
sub findformat($$) {
    my ($file, $manual) = @_;
    my $spec = lc $file;
    my @fileoutput = (
    ['tar+bzip2',      qr/^(GNU|POSIX) tar archive \(bzip2 compressed data(\W|$)/],
    ['tar+gzip',       qr/^(GNU|POSIX) tar archive \(gzip compressed data(\W|$)/],
    ['tar+bzip',       qr/^(GNU|POSIX) tar archive \(bzip compressed data(\W|$)/],
    ['tar+compress',   qr/^(GNU|POSIX) tar archive \(compress'd data(\W|$)/],
    ['tar',            qr/^(GNU|POSIX) tar archive(\W|$)/],
    ['zip',            qr/^Zip archive data(\W|$)/],
    ['rar',            qr/^RAR archive data(\W|$)/],
    ['lha',            qr/^LHa \(2\.x\) archive data /],
    ['lha',            qr/^LHa 2\.x\? archive data /],
    ['lha',            qr/^LHarc 1\.x archive data /],
    ['arj',            qr/^ARJ archive data(\W|$)/],
    ['arc',            qr/^ARC archive data(\W|$)/],
    ['cpio',           qr/^cpio archive$/],
    ['cpio',           qr/^ASCII cpio archive /],
    ['rpm',            qr/^RPM v/],
    ['bzip2',          qr/ \(bzip2 compressed data(\W|$)/],
    ['bzip',           qr/ \(bzip compressed data(\W|$)/],
    ['gzip',           qr/ \(gzip compressed data(\W|$)/],
    ['compress',       qr/ \(compress'd data(\W|$)/],
    ['lzop',           qr/^lzop compressed data /],
    #['bzip2',         qr/^bzip2 compressed data(\W|$)/],
    #['bzip',          qr/^bzip compressed data(\W|$)/],
    #['gzip',          qr/^gzip compressed data(\W|$)/],
    #['compress',      qr/^compress'd data(\W|$)/],
    );
    my @fileextensions = (
    ['tar+bzip',       qr/(\.tar\.bz|\.tbz)$/],
    ['tar+bzip2',      qr/(\.tar\.bz2|\.tbz2)$/],
    ['tar+compress',   qr/(\.tar\.[zZ]|\.t[zZ])$/],
    ['tar+gzip',       qr/(\.tar\.gz|\.tgz)$/],
    ['tar+lzop',       qr/(\.tar\.lzo|\.tzo)$/],
        ['arc',            qr/\.arc$/],
    ['ace',            qr/\.ace$/],
    ['arj',            qr/\.arj$/],
    ['bzip',           qr/\.bz$/],
    ['bzip2',          qr/\.bz2$/],
    ['compress',       qr/\.[zZ]$/],
    ['cpio',           qr/\.cpio$/],
    ['gzip',           qr/\.gz$/],
    ['jar',            qr/\.(jar|war)$/],
    ['lha',            qr/\.(lha|lzh)$/],
    ['lzop',           qr/\.lzo$/],
    ['rar',            qr/\.rar$/],
    ['rpm',            qr/\.rpm$/],
    ['tar',            qr/\.tar$/],
    ['zip',            qr/\.zip$/],
    );

    if ($manual) {
        $spec =~ tr/+/./;
        $spec =~ s/^\.*/\./;
        $spec =~ s/lzop/lzo/;
        $spec =~ s/bzip2/bz2/;
        $spec =~ s/bzip/bz/;
        $spec =~ s/gzip/gz/;
        $spec =~ s/compress/Z/;
    }
    foreach my $formatinfo (@fileextensions) {
        my ($format, $regex) = @{$formatinfo};
        return $format if ($spec =~ $regex);
    }

    if (!$manual && $::cfg_use_file) {
        if (!-e $file) {
            warn "$::basename: ".quote($file).": no such file and cannot identify format from extension\n";
            return;
        }
        if (!sysopen(TMP, $file, O_RDONLY)) {
            warn "$::basename: ".quote($file).": cannot open - $!\n";
            return;
        }
        close TMP;
        if (!-f $file) {
            warn "$::basename: ".quote($file).": not a regular file\n";
            return;
        }
        if ($::opt_verbosity >= 1) {
            warn "$::basename: ".quote($file).": format not known, identifying using file\n";
        }
        my @cmd = ($::cfg_path_file, '-b', '-L', '-z', '--', $file);
        $spec = backticks(@cmd);
        if (!defined $spec) {
            warn "$::basename: $::errmsg\n";
            return;
        }
        if ($? & 0xFF != 0) {
            warn "$::basename: ".quote($::cfg_path_file).": abnormal exit\n";
            return;
        }
        if ($? >> 8 != 0) {
            warn "$::basename: ".quote($file).": unknown file format\n";
            return;
        }
        chomp $spec;
        foreach my $formatinfo (@fileoutput) {
            my ($format, $regex) = @{$formatinfo};
            if ($spec =~ $regex) {
                warn "$::basename: ".quote($file).": format is `$format'\n" if $::opt_verbosity >= 1;
                return $format;
            }
        }
        warn "$::basename: ".quote($file).": unsupported file format `$spec'\n";
        return;
    }
    warn "$::basename: ".quote($file).": unrecognized file format\n";
    return;
}

# backticks(cmdargs, ..)
# An implementation of the backtick (qx//) operator.
# The difference is that command STDERR output will still
# be printed on STDERR, and the shell isn't used to parse
# the command line.
sub backticks(@) {
  if (!pipe(IN,OUT)) {
        $::errmsg = "pipe failed - $!";
        return;
    }
  my $child = fork;
    if (!defined $child) {
        $::errmsg = "fork failed - $!";
        return;
    }
  if ($child == 0) {
    close IN || exit 1;
    close STDOUT || exit 1;
    open(STDOUT, '>&OUT') || exit 1;
        close OUT || exit 1;
    $SIG{__WARN__} = sub {};
    exec(@_) || exit 1;
  }
  close OUT;
  my $text = join('', <IN>);
  close IN;
  if (waitpid($child,0) != $child) {
        $::errmsg = "waitpid failed - $!";
        return;
    }
  return $text;
}

# readconfig(file)
# Read and parse the specified configuration file.
# If the file does not exist, just return.
# If there is an error in the configuration file,
# the program will be terminated. This could be a
# problem when there are errors in the system-wide
# configuration file.
sub readconfig($$) {
    my ($file, $failok) = @_;
    my %optionmap = (
        'args_diff'               => \$::cfg_args_diff,
        'default_verbosity'       => \$::cfg_default_verbosity,
        'keep_compressed'         => \$::cfg_keep_compressed,
        'path_arc'                => \$::cfg_path_arc,
        'path_arj'                => \$::cfg_path_arj,
        'path_bzip'               => \$::cfg_path_bzip,
        'path_bzip2'              => \$::cfg_path_bzip2,
        'path_cat'                => \$::cfg_path_cat,
        'path_compress'           => \$::cfg_path_compress,
        'path_cpio'               => \$::cfg_path_cpio,
        'path_diff'               => \$::cfg_path_diff,
        'path_file'               => \$::cfg_path_file,
        'path_find'               => \$::cfg_path_find,
        'path_gzip'               => \$::cfg_path_gzip,
        'path_jar'                => \$::cfg_path_jar,
        'path_lha'                => \$::cfg_path_lha,
        'path_lzop'               => \$::cfg_path_lzop,
        'path_nomarch'            => \$::cfg_path_nomarch,
        'path_pager'              => \$::cfg_path_pager,
        'path_rar'                => \$::cfg_path_rar,
        'path_rpm'                => \$::cfg_path_rpm,
        'path_rpm2cpio'           => \$::cfg_path_rpm2cpio,
        'path_tar'                => \$::cfg_path_tar,
        'path_unace'              => \$::cfg_path_unace,
        'path_unarj'              => \$::cfg_path_unarj,
        'path_unrar'              => \$::cfg_path_unrar,
        'path_unzip'              => \$::cfg_path_unzip,
        'path_usercfg'            => \$::cfg_path_usercfg,
        'path_xargs'              => \$::cfg_path_xargs,
        'path_zip'                => \$::cfg_path_zip,
        'show_extracted'          => \$::cfg_show_extracted,
        'strip_unknown_ext'       => \$::cfg_strip_unknown_ext,
        'tmpdir_name'             => \$::cfg_tmpdir_name,
        'use_arc_for_unpack'      => \$::cfg_use_arc_for_unpack,
        'use_arj_for_unpack'      => \$::cfg_use_arc_for_unpack,
        'use_file'                => \$::cfg_use_file,
        'use_find_cpio_print0'    => \$::cfg_use_find_cpio_print0,
        'use_gzip_for_z'          => \$::cfg_use_gzip_for_z,
        'use_jar'                 => \$::cfg_use_jar,
        'use_rar_for_unpack'      => \$::cfg_use_rar_for_unpack,
        'use_rar_for_unrar'             => [ 'use_rar_for_unpack', \$::cfg_use_rar_for_unpack ],
        'use_tar_bzip2_option'    => \$::cfg_use_tar_bzip2_option,
        'use_tar_j_option'              => [ 'use_tar_bzip2_option', \$::cfg_use_tar_bzip2_option ],
        'use_tar_z_option'        => \$::cfg_use_tar_z_option,
    );
    return if ($failok && !-e $file);
    sysopen(FILE, $file, O_RDONLY) || die "$::basename: ".quote($file).": cannot open for reading - $!\n";    #OK
    while (<FILE>) {
        chomp;
        next if /^\s*(#(.*))?$/;
        my ($var,$val) = /^(.*?)\s+([^\s].*)$/;
        my $varref = undef;
        if (exists $optionmap{$var}) {
            if (ref $optionmap{$var} eq 'ARRAY') {
                my ($newopt,$newref) = @{$optionmap{$var}};
                warn quote($file).": $var is obsolete (use $newopt)\n";
                ${$newref} = $val;
            } else {
                ${$optionmap{$var}} = $val;
            }
        }
        else {
            die "$::basename: ".quote($file).":$.: unrecognized directive\n";
        }
    }
    close(FILE);
}

# Remove a directory recursively. This function used to change
# the mode on the directories is traverses, but I now consider
# that to be unsafe (what if there's a bug in atool and it
# removes a file it shouldn't?).
sub unlink_directory($) {
    my ($dir) = @_;
    die "$::basename: internal error 1 - please report this bug\n"
        if ($dir eq '/' || $dir eq $ENV{HOME});
#    chmod 0700, $dir || die "$::basename: cannot chmod `".quote($dir)."': $!\n";
    chdir $dir || die "$::basename: ".quote($dir).": cannot change to - $!\n";
    opendir(DIR, $::cur) || die "$::basename: ".quote($dir).": cannot list - $!\n";
    my @files = readdir(DIR);
    closedir(DIR);
    foreach my $file (@files) {
        next if $file eq $::cur || $file eq $::up;
        if (!-d $file) {
            unlink $file || die "$::basename: ".quote($file).": cannot remove - $!\n";
        } else {
            unlink_directory($file);
        }
    }
    chdir $::up || die "$::basename: $::up: cannot change to - $!\n";
    rmdir $dir || die "$::basename: ".quote($dir).": cannot remove - $!\n";
}

# find_comparable_file(dir)
# Assuming that the contents of some archive has been extracted to dir,
# this function will determine the main file or directory in this
# archive - the file or directory which will be compared when this
# archive is compared to some other.
sub find_comparable_file($) {
    my ($dir) = @_;
    my $result = $dir;
    if (opendir(DIR, $dir)) {
        my (@files) = map { readdir(DIR) } 0..3;
        if (@files == 3 && $files[0] eq $::cur && $files[1] eq $::up) {
            $result = File::Spec->catfile($dir, $files[2]);
        }
        closedir(DIR);
    }
    return $result;
}

# makeabsolute(file)
# Return the absolute version of file.
sub makeabsolute($) {
    my ($file) = @_;
    return $file if (substr($file, 0, 1) eq '/');
    return File::Spec->catfile(getcwd(), $file);
}

# quote(string)
# Quote a style like the GNU fileutils would do (`locale'
# quoting style).
sub quote($) {
  my ($in) = @_;
    my $out = '';
    for (my $c = 0; $c < length($in); $c++) {
        my $ch = substr($in, $c, 1);
        if ($ch eq "\b") {
            $out .= "\\b";
        } elsif ($ch eq "\f") {
            $out .= "\\f";
        } elsif ($ch eq "\n") {
            $out .= "\\n";
        } elsif ($ch eq "\r") {
            $out .= "\\r";
        } elsif ($ch eq "\t") {
            $out .= "\\t";
        } elsif (ord($ch) == 11) {            # Vertical Tab, \v
            $out .= "\\v";
        } elsif ($ch eq "\\") {
            $out .= "\\\\";
        } elsif ($ch eq "'") {
            $out .= "\\'";
        } elsif (!POSIX::isprint($ch)) {
            $out .= sprintf('\\%03o', ord($ch));
        } else {
            $out .= $ch;
        }
    }
  return $out;
}

# shell_execute(@)
# Execute a command with pipes and output redirection like the
# shell does. Only difference is we do it without the shell.
# This reason for this is because we don't have to quote
# meta-characters - some meta-characters like LF and DEL are
# unquotable!
sub shell_execute(@) {
    my (@cmdspec) = @_;

    my @cmds = ();
    my $start = 0;
    my $redir_out = undef;
    for (my $c = 0; $c < @cmdspec; $c++) {
        if (ref $cmdspec[$c]) {
            push @cmds, [ @cmdspec[$start..$c-1] ];
            $start = $c+1;
            $redir_out = $cmdspec[$c+1] if (${$cmdspec[$c]}[0] eq '>');
        }
    }
    push @cmds, [ @cmdspec[$start..$#cmdspec] ] if !defined $redir_out;

    $SIG{INT} = 'IGNORE';

    my @ip = ();
    my @op = ();
    my @children = ();
    for (my $c = 0; $c <= $#cmds; $c++) {
        if ($c != $#cmds) {
            @op = reverse POSIX::pipe();
            if (!@op || !defined $op[0] || !defined $op[1]) {
                $::errmsg = "pipe failed - $!";
                return 0;
            }
        }
        if ($c == $#cmds && defined $redir_out) {
            @_ = (); # XXX: necessary to overcome POSIX autoload bug!
            @op = (POSIX::open($redir_out, &POSIX::O_WRONLY | &POSIX::O_CREAT));
            if (!@op || !defined $op[0]) {
                $::errmsg = quote($redir_out).": cannot open for writing - $!";
                return 0;
            }
        }
        my $pid = fork();
        die "fork failed - $!\n" if !defined $pid;
        if ($pid == 0) {
            $SIG{INT} = '';
            if (@ip) {
                die "dup2 failed - $!\n" if POSIX::dup2($ip[1], 0) < 0;
                POSIX::close($_) foreach (@ip);
            }
            if (@op) {
                die "dup2 failed - $!\n" if POSIX::dup2($op[0], 1) < 0;
                POSIX::close($_) foreach (@op);
            }
            exec(@{$cmds[$c]}) || die ${$cmds[$c]}[0].": cannot execute - $!\n";
        }
        POSIX::close($op[0]) if ($c == $#cmds && defined $redir_out);
        POSIX::close($_) foreach (@ip);
        @ip = @op;
        @op = ();
        push @children, $pid;
    }

    foreach (@children) {
        if (waitpid($_,0) < 0) {
            $::errmsg = "waitpid failed - $!";
            return 0;
        }
    }
    $SIG{INT} = '';

    return 1;
}

# Write dir to file indicated by $::opt_save_outdir.
#
sub save_outdir($) {
    my ($dir) = @_;
    if (defined $::opt_save_outdir && !-l $dir && -d $dir) {
        if (!sysopen(TMP, $::opt_save_outdir, O_WRONLY)) {
            warn die "$::basename: ".quote($::opt_save_outdir).": cannot open for writing - $!\n";
        } else {
            print TMP $dir, "\n";
            close(TMP);
        }
    }
}

# Somewhat stupid subroutine to add xargs to the command line.
#
sub handle_empty_add(@) {
    my @cmd = @_;
    unshift @cmd, '--';
    unshift @cmd, '-0' if ($::opt_null);
    unshift @cmd, $::cfg_path_xargs;
    return @cmd;
}

# Return a suitable pager command
#
sub get_pager_program {
    return $ENV{PAGER} if (exists $ENV{PAGER});
    return $::cfg_path_pager;
}

sub END {
    map (rmdir, @::rmdirs) if !$::opt_simulate;    # Errors are ignored
}