[p5sagit/p5-mst-13.2.git] / lib / Cwd.pm

package Cwd;
require 5.000;

=head1 NAME

getcwd - get pathname of current working directory

=head1 SYNOPSIS

    use Cwd;
    $dir = cwd;

    use Cwd;
    $dir = getcwd;

    use Cwd;
    $dir = fastgetcwd;

    use Cwd 'chdir';
    chdir "/tmp";
    print $ENV{'PWD'};

    use Cwd 'abs_path';
    print abs_path($ENV{'PWD'});

    use Cwd 'fast_abs_path';
    print fast_abs_path($ENV{'PWD'});

=head1 DESCRIPTION

The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions
in Perl.

The abs_path() function takes a single argument and returns the
absolute pathname for that argument. It uses the same algoritm as
getcwd(). (actually getcwd() is abs_path("."))

The fastcwd() function looks the same as getcwd(), but runs faster.
It's also more dangerous because it might conceivably chdir() you out
of a directory that it can't chdir() you back into.  If fastcwd
encounters a problem it will return undef but will probably leave you
in a different directory.  For a measure of extra security, if
everything appears to have worked, the fastcwd() function will check
that it leaves you in the same directory that it started in. If it has
changed it will C<die> with the message "Unstable directory path,
current directory changed unexpectedly". That should never happen.

The fast_abs_path() function looks the same as abs_path(), but runs faster.
And like fastcwd() is more dangerous.

The cwd() function looks the same as getcwd and fastgetcwd but is
implemented using the most natural and safe form for the current
architecture. For most systems it is identical to `pwd` (but without
the trailing line terminator).

It is recommended that cwd (or another *cwd() function) is used in
I<all> code to ensure portability.

If you ask to override your chdir() built-in function, then your PWD
environment variable will be kept up to date.  (See
L<perlsub/Overriding Builtin Functions>.) Note that it will only be
kept up to date if all packages which use chdir import it from Cwd.

=cut

## use strict;

use Carp;

$VERSION = '2.01';

require Exporter;
@ISA = qw(Exporter);
@EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
@EXPORT_OK = qw(chdir abs_path fast_abs_path);


# The 'natural and safe form' for UNIX (pwd may be setuid root)

sub _backtick_pwd {
    my $cwd;
    chop($cwd = `pwd`);
    $cwd;
}

# Since some ports may predefine cwd internally (e.g., NT)
# we take care not to override an existing definition for cwd().

*cwd = \&_backtick_pwd unless defined &cwd;


# By Brandon S. Allbery
#
# Usage: $cwd = getcwd();

sub getcwd
{
    abs_path('.');
}

# By John Bazik
#
# Usage: $cwd = &fastcwd;
#
# This is a faster version of getcwd.  It's also more dangerous because
# you might chdir out of a directory that you can't chdir back into.
    
# List of metachars taken from do_exec() in doio.c
my $quoted_shell_meta = quotemeta('$&*(){}[]";\\|?<>~`'."'\n");

sub fastcwd {
    my($odev, $oino, $cdev, $cino, $tdev, $tino);
    my(@path, $path);
    local(*DIR);

    my($orig_cdev, $orig_cino) = stat('.');
    ($cdev, $cino) = ($orig_cdev, $orig_cino);
    for (;;) {
	my $direntry;
	($odev, $oino) = ($cdev, $cino);
	CORE::chdir('..') || return undef;
	($cdev, $cino) = stat('.');
	last if $odev == $cdev && $oino == $cino;
	opendir(DIR, '.') || return undef;
	for (;;) {
	    $direntry = readdir(DIR);
	    last unless defined $direntry;
	    next if $direntry eq '.';
	    next if $direntry eq '..';

	    ($tdev, $tino) = lstat($direntry);
	    last unless $tdev != $odev || $tino != $oino;
	}
	closedir(DIR);
	return undef unless defined $direntry; # should never happen
	unshift(@path, $direntry);
    }
    $path = '/' . join('/', @path);
    # At this point $path may be tainted (if tainting) and chdir would fail.
    # To be more useful we untaint it then check that we landed where we started.
    $path = $1 if $path =~ /^(.*)$/;	# untaint
    CORE::chdir($path) || return undef;
    ($cdev, $cino) = stat('.');
    die "Unstable directory path, current directory changed unexpectedly"
	if $cdev != $orig_cdev || $cino != $orig_cino;
    $path;
}


# Keeps track of current working directory in PWD environment var
# Usage:
#	use Cwd 'chdir';
#	chdir $newdir;

my $chdir_init = 0;

sub chdir_init {
    if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos') {
	my($dd,$di) = stat('.');
	my($pd,$pi) = stat($ENV{'PWD'});
	if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {
	    $ENV{'PWD'} = cwd();
	}
    }
    else {
	$ENV{'PWD'} = cwd();
    }
    # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar)
    if ($ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|) {
	my($pd,$pi) = stat($2);
	my($dd,$di) = stat($1);
	if (defined $pd and defined $dd and $di == $pi and $dd == $pd) {
	    $ENV{'PWD'}="$2$3";
	}
    }
    $chdir_init = 1;
}

sub chdir {
    my $newdir = shift || '';	# allow for no arg (chdir to HOME dir)
    $newdir =~ s|///*|/|g;
    chdir_init() unless $chdir_init;
    return 0 unless CORE::chdir $newdir;
    if ($^O eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} }

    if ($newdir =~ m#^/#) {
	$ENV{'PWD'} = $newdir;
    } else {
	my @curdir = split(m#/#,$ENV{'PWD'});
	@curdir = ('') unless @curdir;
	my $component;
	foreach $component (split(m#/#, $newdir)) {
	    next if $component eq '.';
	    pop(@curdir),next if $component eq '..';
	    push(@curdir,$component);
	}
	$ENV{'PWD'} = join('/',@curdir) || '/';
    }
    1;
}

# Taken from Cwd.pm It is really getcwd with an optional
# parameter instead of '.'
#

sub abs_path
{
    my $start = @_ ? shift : '.';
    my($dotdots, $cwd, @pst, @cst, $dir, @tst);

    unless (@cst = stat( $start ))
    {
	carp "stat($start): $!";
	return '';
    }
    $cwd = '';
    $dotdots = $start;
    do
    {
	$dotdots .= '/..';
	@pst = @cst;
	unless (opendir(PARENT, $dotdots))
	{
	    carp "opendir($dotdots): $!";
	    return '';
	}
	unless (@cst = stat($dotdots))
	{
	    carp "stat($dotdots): $!";
	    closedir(PARENT);
	    return '';
	}
	if ($pst[0] == $cst[0] && $pst[1] == $cst[1])
	{
	    $dir = undef;
	}
	else
	{
	    do
	    {
		unless (defined ($dir = readdir(PARENT)))
	        {
		    carp "readdir($dotdots): $!";
		    closedir(PARENT);
		    return '';
		}
		$tst[0] = $pst[0]+1 unless (@tst = lstat("$dotdots/$dir"))
	    }
	    while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] ||
		   $tst[1] != $pst[1]);
	}
	$cwd = (defined $dir ? "$dir" : "" ) . "/$cwd" ;
	closedir(PARENT);
    } while (defined $dir);
    chop($cwd) unless $cwd eq '/'; # drop the trailing /
    $cwd;
}

sub fast_abs_path {
    my $cwd = getcwd();
    my $path = shift || '.';
    CORE::chdir($path) || croak "Cannot chdir to $path:$!";
    my $realpath = getcwd();
    CORE::chdir($cwd)  || croak "Cannot chdir back to $cwd:$!";
    $realpath;
}


# --- PORTING SECTION ---

# VMS: $ENV{'DEFAULT'} points to default directory at all times
# 06-Mar-1996  Charles Bailey  bailey@newman.upenn.edu
# Note: Use of Cwd::chdir() causes the logical name PWD to be defined
#   in the process logical name table as the default device and directory
#   seen by Perl. This may not be the same as the default device
#   and directory seen by DCL after Perl exits, since the effects
#   the CRTL chdir() function persist only until Perl exits.

sub _vms_cwd {
    return $ENV{'DEFAULT'};
}

sub _vms_abs_path {
    return $ENV{'DEFAULT'} unless @_;
    my $path = VMS::Filespec::pathify($_[0]);
    croak("Invalid path name $_[0]") unless defined $path;
    return VMS::Filespec::rmsexpand($path);
}

sub _os2_cwd {
    $ENV{'PWD'} = `cmd /c cd`;
    chop $ENV{'PWD'};
    $ENV{'PWD'} =~ s:\\:/:g ;
    return $ENV{'PWD'};
}

sub _win32_cwd {
    $ENV{'PWD'} = Win32::GetCwd();
    $ENV{'PWD'} =~ s:\\:/:g ;
    return $ENV{'PWD'};
}

*_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd && 
                            defined &Win32::GetCwd);

*_NT_cwd = \&_os2_cwd unless defined &_NT_cwd;

sub _dos_cwd {
    if (!defined &Dos::GetCwd) {
        $ENV{'PWD'} = `command /c cd`;
        chop $ENV{'PWD'};
        $ENV{'PWD'} =~ s:\\:/:g ;
    } else {
        $ENV{'PWD'} = Dos::GetCwd();
    }
    return $ENV{'PWD'};
}

sub _qnx_cwd {
    $ENV{'PWD'} = `/usr/bin/fullpath -t`;
    chop $ENV{'PWD'};
    return $ENV{'PWD'};
}

sub _qnx_abs_path {
    my $path = shift || '.';
    my $realpath=`/usr/bin/fullpath -t $path`;
    chop $realpath;
    return $realpath;
}

{
    local $^W = 0;	# assignments trigger 'subroutine redefined' warning

    if ($^O eq 'VMS') {
        *cwd		= \&_vms_cwd;
        *getcwd		= \&_vms_cwd;
        *fastcwd	= \&_vms_cwd;
        *fastgetcwd	= \&_vms_cwd;
        *abs_path	= \&_vms_abs_path;
        *fast_abs_path	= \&_vms_abs_path;
    }
    elsif ($^O eq 'NT' or $^O eq 'MSWin32') {
        # We assume that &_NT_cwd is defined as an XSUB or in the core.
        *cwd		= \&_NT_cwd;
        *getcwd		= \&_NT_cwd;
        *fastcwd	= \&_NT_cwd;
        *fastgetcwd	= \&_NT_cwd;
        *abs_path	= \&fast_abs_path;
    }
    elsif ($^O eq 'os2') {
        # sys_cwd may keep the builtin command
        *cwd		= defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
        *getcwd		= \&cwd;
        *fastgetcwd	= \&cwd;
        *fastcwd	= \&cwd;
        *abs_path	= \&fast_abs_path;
    }
    elsif ($^O eq 'dos') {
        *cwd		= \&_dos_cwd;
        *getcwd		= \&_dos_cwd;
        *fastgetcwd	= \&_dos_cwd;
        *fastcwd	= \&_dos_cwd;
        *abs_path	= \&fast_abs_path;
    }
    elsif ($^O eq 'qnx') {
        *cwd		= \&_qnx_cwd;
        *getcwd		= \&_qnx_cwd;
        *fastgetcwd	= \&_qnx_cwd;
        *fastcwd	= \&_qnx_cwd;
        *abs_path	= \&_qnx_abs_path;
        *fast_abs_path	= \&_qnx_abs_path;
    }
}

# package main; eval join('',<DATA>) || die $@;	# quick test

1;

__END__
BEGIN { import Cwd qw(:DEFAULT chdir); }
print join("\n", cwd, getcwd, fastcwd, "");
chdir('..');
print join("\n", cwd, getcwd, fastcwd, "");
print "$ENV{PWD}\n";
Commit	Line	Data
a0d0e21e	1	package Cwd;
a0d0e21e	2	require 5.000;
a0d0e21e	3
f06db76b	4	=head1 NAME
	5
	6	getcwd - get pathname of current working directory
	7
	8	=head1 SYNOPSIS
	9
4633a7c4	10	use Cwd;
	11	$dir = cwd;
	12
	13	use Cwd;
	14	$dir = getcwd;
f06db76b	15
f06db76b	16	use Cwd;
4633a7c4	17	$dir = fastgetcwd;
f06db76b	18
	19	use Cwd 'chdir';
	20	chdir "/tmp";
	21	print $ENV{'PWD'};
	22
20408e3c	23	use Cwd 'abs_path';
	24	print abs_path($ENV{'PWD'});
	25
	26	use Cwd 'fast_abs_path';
	27	print fast_abs_path($ENV{'PWD'});
	28
f06db76b	29	=head1 DESCRIPTION
	30
	31	The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions
4633a7c4	32	in Perl.
f06db76b	33
20408e3c	34	The abs_path() function takes a single argument and returns the
	35	absolute pathname for that argument. It uses the same algoritm as
	36	getcwd(). (actually getcwd() is abs_path("."))
	37
cb1a09d0	38	The fastcwd() function looks the same as getcwd(), but runs faster.
fb73857a	39	It's also more dangerous because it might conceivably chdir() you out
	40	of a directory that it can't chdir() you back into. If fastcwd
	41	encounters a problem it will return undef but will probably leave you
	42	in a different directory. For a measure of extra security, if
	43	everything appears to have worked, the fastcwd() function will check
	44	that it leaves you in the same directory that it started in. If it has
	45	changed it will C<die> with the message "Unstable directory path,
	46	current directory changed unexpectedly". That should never happen.
f06db76b	47
20408e3c	48	The fast_abs_path() function looks the same as abs_path(), but runs faster.
	49	And like fastcwd() is more dangerous.
	50
4633a7c4	51	The cwd() function looks the same as getcwd and fastgetcwd but is
	52	implemented using the most natural and safe form for the current
	53	architecture. For most systems it is identical to `pwd` (but without
fb73857a	54	the trailing line terminator).
	55
	56	It is recommended that cwd (or another *cwd() function) is used in
	57	I<all> code to ensure portability.
4633a7c4	58
	59	If you ask to override your chdir() built-in function, then your PWD
	60	environment variable will be kept up to date. (See
55497cff	61	L<perlsub/Overriding Builtin Functions>.) Note that it will only be
1fef88e7	62	kept up to date if all packages which use chdir import it from Cwd.
4633a7c4	63
f06db76b	64	=cut
f06db76b	65
96e4d5b1	66	## use strict;
	67
	68	use Carp;
	69
07569ed3	70	$VERSION = '2.01';
96e4d5b1	71
96e4d5b1	72	require Exporter;
a0d0e21e	73	@ISA = qw(Exporter);
e7ae0116	74	@EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
96e4d5b1	75	@EXPORT_OK = qw(chdir abs_path fast_abs_path);
a0d0e21e	76
4633a7c4	77
8b88ae92	78	# The 'natural and safe form' for UNIX (pwd may be setuid root)
96e4d5b1	79
8b88ae92	80	sub _backtick_pwd {
4633a7c4	81	my $cwd;
	82	chop($cwd = `pwd`);
	83	$cwd;
8b88ae92	84	}
4633a7c4	85
	86	# Since some ports may predefine cwd internally (e.g., NT)
	87	# we take care not to override an existing definition for cwd().
	88
	89	*cwd = \&_backtick_pwd unless defined &cwd;
a0d0e21e	90
748a9306	91
a0d0e21e	92	# By Brandon S. Allbery
	93	#
	94	# Usage: $cwd = getcwd();
	95
	96	sub getcwd
	97	{
07569ed3	98	abs_path('.');
a0d0e21e	99	}
a0d0e21e	100
a0d0e21e	101	# By John Bazik
	102	#
	103	# Usage: $cwd = &fastcwd;
	104	#
	105	# This is a faster version of getcwd. It's also more dangerous because
	106	# you might chdir out of a directory that you can't chdir back into.
fb73857a	107
	108	# List of metachars taken from do_exec() in doio.c
	109	my $quoted_shell_meta = quotemeta('$&*(){}[]";\\\|?<>~`'."'\n");
a0d0e21e	110
	111	sub fastcwd {
	112	my($odev, $oino, $cdev, $cino, $tdev, $tino);
	113	my(@path, $path);
	114	local(*DIR);
	115
fb73857a	116	my($orig_cdev, $orig_cino) = stat('.');
fb73857a	117	($cdev, $cino) = ($orig_cdev, $orig_cino);
a0d0e21e	118	for (;;) {
40000a8c	119	my $direntry;
a0d0e21e	120	($odev, $oino) = ($cdev, $cino);
e79e61e4	121	CORE::chdir('..') \|\| return undef;
a0d0e21e	122	($cdev, $cino) = stat('.');
a0d0e21e	123	last if $odev == $cdev && $oino == $cino;
fb73857a	124	opendir(DIR, '.') \|\| return undef;
a0d0e21e	125	for (;;) {
40000a8c	126	$direntry = readdir(DIR);
fb73857a	127	last unless defined $direntry;
40000a8c	128	next if $direntry eq '.';
40000a8c	129	next if $direntry eq '..';
a0d0e21e	130
40000a8c	131	($tdev, $tino) = lstat($direntry);
a0d0e21e	132	last unless $tdev != $odev \|\| $tino != $oino;
	133	}
	134	closedir(DIR);
fb73857a	135	return undef unless defined $direntry; # should never happen
40000a8c	136	unshift(@path, $direntry);
a0d0e21e	137	}
fb73857a	138	$path = '/' . join('/', @path);
	139	# At this point $path may be tainted (if tainting) and chdir would fail.
	140	# To be more useful we untaint it then check that we landed where we started.
	141	$path = $1 if $path =~ /^(.*)$/; # untaint
e79e61e4	142	CORE::chdir($path) \|\| return undef;
fb73857a	143	($cdev, $cino) = stat('.');
	144	die "Unstable directory path, current directory changed unexpectedly"
	145	if $cdev != $orig_cdev \|\| $cino != $orig_cino;
a0d0e21e	146	$path;
	147	}
	148
	149
4633a7c4	150	# Keeps track of current working directory in PWD environment var
a0d0e21e	151	# Usage:
	152	# use Cwd 'chdir';
	153	# chdir $newdir;
	154
4633a7c4	155	my $chdir_init = 0;
a0d0e21e	156
4633a7c4	157	sub chdir_init {
39e571d4	158	if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos') {
a0d0e21e	159	my($dd,$di) = stat('.');
	160	my($pd,$pi) = stat($ENV{'PWD'});
	161	if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {
4633a7c4	162	$ENV{'PWD'} = cwd();
a0d0e21e	163	}
	164	}
	165	else {
4633a7c4	166	$ENV{'PWD'} = cwd();
a0d0e21e	167	}
4633a7c4	168	# Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar)
a0d0e21e	169	if ($ENV{'PWD'} =~ m\|(/[^/]+(/[^/]+/[^/]+))(.*)\|) {
	170	my($pd,$pi) = stat($2);
	171	my($dd,$di) = stat($1);
	172	if (defined $pd and defined $dd and $di == $pi and $dd == $pd) {
	173	$ENV{'PWD'}="$2$3";
	174	}
	175	}
	176	$chdir_init = 1;
	177	}
	178
	179	sub chdir {
4633a7c4	180	my $newdir = shift \|\| ''; # allow for no arg (chdir to HOME dir)
4633a7c4	181	$newdir =~ s\|///*\|/\|g;
a0d0e21e	182	chdir_init() unless $chdir_init;
4633a7c4	183	return 0 unless CORE::chdir $newdir;
c6538b72	184	if ($^O eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} }
748a9306	185
a0d0e21e	186	if ($newdir =~ m#^/#) {
a0d0e21e	187	$ENV{'PWD'} = $newdir;
4633a7c4	188	} else {
	189	my @curdir = split(m#/#,$ENV{'PWD'});
	190	@curdir = ('') unless @curdir;
	191	my $component;
a0d0e21e	192	foreach $component (split(m#/#, $newdir)) {
	193	next if $component eq '.';
	194	pop(@curdir),next if $component eq '..';
	195	push(@curdir,$component);
	196	}
	197	$ENV{'PWD'} = join('/',@curdir) \|\| '/';
	198	}
4633a7c4	199	1;
a0d0e21e	200	}
a0d0e21e	201
8b88ae92	202	# Taken from Cwd.pm It is really getcwd with an optional
	203	# parameter instead of '.'
	204	#
	205
	206	sub abs_path
	207	{
07569ed3	208	my $start = @_ ? shift : '.';
8b88ae92	209	my($dotdots, $cwd, @pst, @cst, $dir, @tst);
	210
	211	unless (@cst = stat( $start ))
	212	{
	213	carp "stat($start): $!";
	214	return '';
	215	}
	216	$cwd = '';
	217	$dotdots = $start;
	218	do
	219	{
	220	$dotdots .= '/..';
	221	@pst = @cst;
	222	unless (opendir(PARENT, $dotdots))
	223	{
	224	carp "opendir($dotdots): $!";
	225	return '';
	226	}
	227	unless (@cst = stat($dotdots))
	228	{
	229	carp "stat($dotdots): $!";
	230	closedir(PARENT);
	231	return '';
	232	}
	233	if ($pst[0] == $cst[0] && $pst[1] == $cst[1])
	234	{
07569ed3	235	$dir = undef;
8b88ae92	236	}
	237	else
	238	{
	239	do
	240	{
	241	unless (defined ($dir = readdir(PARENT)))
	242	{
	243	carp "readdir($dotdots): $!";
	244	closedir(PARENT);
	245	return '';
	246	}
	247	$tst[0] = $pst[0]+1 unless (@tst = lstat("$dotdots/$dir"))
	248	}
	249	while ($dir eq '.' \|\| $dir eq '..' \|\| $tst[0] != $pst[0] \|\|
	250	$tst[1] != $pst[1]);
	251	}
07569ed3	252	$cwd = (defined $dir ? "$dir" : "" ) . "/$cwd" ;
8b88ae92	253	closedir(PARENT);
07569ed3	254	} while (defined $dir);
07569ed3	255	chop($cwd) unless $cwd eq '/'; # drop the trailing /
8b88ae92	256	$cwd;
	257	}
	258
96e4d5b1	259	sub fast_abs_path {
	260	my $cwd = getcwd();
	261	my $path = shift \|\| '.';
e79e61e4	262	CORE::chdir($path) \|\| croak "Cannot chdir to $path:$!";
96e4d5b1	263	my $realpath = getcwd();
e79e61e4	264	CORE::chdir($cwd) \|\| croak "Cannot chdir back to $cwd:$!";
96e4d5b1	265	$realpath;
8b88ae92	266	}
8b88ae92	267
4633a7c4	268
	269	# --- PORTING SECTION ---
	270
	271	# VMS: $ENV{'DEFAULT'} points to default directory at all times
bd3fa61c	272	# 06-Mar-1996 Charles Bailey bailey@newman.upenn.edu
c6538b72	273	# Note: Use of Cwd::chdir() causes the logical name PWD to be defined
8b88ae92	274	# in the process logical name table as the default device and directory
8b88ae92	275	# seen by Perl. This may not be the same as the default device
4633a7c4	276	# and directory seen by DCL after Perl exits, since the effects
4633a7c4	277	# the CRTL chdir() function persist only until Perl exits.
4633a7c4	278
4633a7c4	279	sub _vms_cwd {
96e4d5b1	280	return $ENV{'DEFAULT'};
	281	}
	282
	283	sub _vms_abs_path {
	284	return $ENV{'DEFAULT'} unless @_;
	285	my $path = VMS::Filespec::pathify($_[0]);
	286	croak("Invalid path name $_[0]") unless defined $path;
	287	return VMS::Filespec::rmsexpand($path);
4633a7c4	288	}
68dc0745	289
4633a7c4	290	sub _os2_cwd {
	291	$ENV{'PWD'} = `cmd /c cd`;
	292	chop $ENV{'PWD'};
	293	$ENV{'PWD'} =~ s:\\:/:g ;
	294	return $ENV{'PWD'};
	295	}
	296
96e4d5b1	297	sub _win32_cwd {
2d7a9237	298	$ENV{'PWD'} = Win32::GetCwd();
96e4d5b1	299	$ENV{'PWD'} =~ s:\\:/:g ;
	300	return $ENV{'PWD'};
	301	}
	302
	303	*_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd &&
2d7a9237	304	defined &Win32::GetCwd);
96e4d5b1	305
96e4d5b1	306	*_NT_cwd = \&_os2_cwd unless defined &_NT_cwd;
68dc0745	307
39e571d4	308	sub _dos_cwd {
	309	if (!defined &Dos::GetCwd) {
	310	$ENV{'PWD'} = `command /c cd`;
	311	chop $ENV{'PWD'};
	312	$ENV{'PWD'} =~ s:\\:/:g ;
	313	} else {
	314	$ENV{'PWD'} = Dos::GetCwd();
	315	}
55497cff	316	return $ENV{'PWD'};
	317	}
	318
7fbf1995	319	sub _qnx_cwd {
	320	$ENV{'PWD'} = `/usr/bin/fullpath -t`;
	321	chop $ENV{'PWD'};
	322	return $ENV{'PWD'};
	323	}
	324
	325	sub _qnx_abs_path {
	326	my $path = shift \|\| '.';
	327	my $realpath=`/usr/bin/fullpath -t $path`;
	328	chop $realpath;
	329	return $realpath;
	330	}
	331
ac1ad7f0	332	{
ac1ad7f0	333	local $^W = 0; # assignments trigger 'subroutine redefined' warning
4633a7c4	334
ac1ad7f0	335	if ($^O eq 'VMS') {
96e4d5b1	336	*cwd = \&_vms_cwd;
	337	*getcwd = \&_vms_cwd;
	338	*fastcwd = \&_vms_cwd;
	339	*fastgetcwd = \&_vms_cwd;
	340	*abs_path = \&_vms_abs_path;
	341	*fast_abs_path = \&_vms_abs_path;
ac1ad7f0	342	}
	343	elsif ($^O eq 'NT' or $^O eq 'MSWin32') {
	344	# We assume that &_NT_cwd is defined as an XSUB or in the core.
96e4d5b1	345	*cwd = \&_NT_cwd;
	346	*getcwd = \&_NT_cwd;
	347	*fastcwd = \&_NT_cwd;
	348	*fastgetcwd = \&_NT_cwd;
	349	*abs_path = \&fast_abs_path;
ac1ad7f0	350	}
	351	elsif ($^O eq 'os2') {
	352	# sys_cwd may keep the builtin command
96e4d5b1	353	*cwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
	354	*getcwd = \&cwd;
	355	*fastgetcwd = \&cwd;
	356	*fastcwd = \&cwd;
	357	*abs_path = \&fast_abs_path;
ac1ad7f0	358	}
39e571d4	359	elsif ($^O eq 'dos') {
	360	*cwd = \&_dos_cwd;
	361	*getcwd = \&_dos_cwd;
	362	*fastgetcwd = \&_dos_cwd;
	363	*fastcwd = \&_dos_cwd;
96e4d5b1	364	*abs_path = \&fast_abs_path;
ac1ad7f0	365	}
7fbf1995	366	elsif ($^O eq 'qnx') {
	367	*cwd = \&_qnx_cwd;
	368	*getcwd = \&_qnx_cwd;
	369	*fastgetcwd = \&_qnx_cwd;
	370	*fastcwd = \&_qnx_cwd;
	371	*abs_path = \&_qnx_abs_path;
	372	*fast_abs_path = \&_qnx_abs_path;
	373	}
55497cff	374	}
4633a7c4	375
	376	# package main; eval join('',<DATA>) \|\| die $@; # quick test
	377
a0d0e21e	378	1;
a0d0e21e	379
4633a7c4	380	__END__
	381	BEGIN { import Cwd qw(:DEFAULT chdir); }
	382	print join("\n", cwd, getcwd, fastcwd, "");
	383	chdir('..');
	384	print join("\n", cwd, getcwd, fastcwd, "");
	385	print "$ENV{PWD}\n";