package Cwd;
require 5.000;
-require Exporter;
-require Config;
-
-# Use osname for portability switches (doubled to cheaply avoid -w warning)
-my $osname = $Config::Config{'osname'} || $Config::Config{'osname'};
-
=head1 NAME
The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions
in Perl.
-The fastgetcwd() function looks the same as getcwd(), but runs faster.
-It's also more dangerous because you might conceivably chdir() out of a
-directory that you can't chdir() back into.
+The fastcwd() function looks the same as getcwd(), but runs faster.
+It's also more dangerous because it might conceivably chdir() you out
+of a directory that it can't chdir() you back into. If fastcwd
+encounters a problem it will return undef but will probably leave you
+in a different directory. For a measure of extra security, if
+everything appears to have worked, the fastcwd() function will check
+that it leaves you in the same directory that it started in. If it has
+changed it will C<die> with the message "Unstable directory path,
+current directory changed unexpectedly". That should never happen.
The cwd() function looks the same as getcwd and fastgetcwd but is
implemented using the most natural and safe form for the current
architecture. For most systems it is identical to `pwd` (but without
-the trailing line terminator). It is recommended that cwd (or another
-*cwd() function) is used in I<all> code to ensure portability.
+the trailing line terminator).
+
+It is recommended that cwd (or another *cwd() function) is used in
+I<all> code to ensure portability.
If you ask to override your chdir() built-in function, then your PWD
environment variable will be kept up to date. (See
-L<perlsub/Overriding builtin functions>.) Note that it will only be
-kept up to date it all packages which use chdir import it from Cwd.
+L<perlsub/Overriding Builtin Functions>.) Note that it will only be
+kept up to date if all packages which use chdir import it from Cwd.
=cut
+## use strict;
+
+use Carp;
+
+$VERSION = '2.00';
+
+require Exporter;
@ISA = qw(Exporter);
-@EXPORT = qw(cwd getcwd fastcwd);
-@EXPORT_OK = qw(chdir);
+@EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
+@EXPORT_OK = qw(chdir abs_path fast_abs_path);
+
-# use strict;
+# The 'natural and safe form' for UNIX (pwd may be setuid root)
-sub _backtick_pwd { # The 'natural and safe form' for UNIX (pwd may be setuid root)
+sub _backtick_pwd {
my $cwd;
chop($cwd = `pwd`);
$cwd;
-}
+}
# Since some ports may predefine cwd internally (e.g., NT)
# we take care not to override an existing definition for cwd().
}
if ($pst[0] == $cst[0] && $pst[1] == $cst[1])
{
- $dir = '';
+ $dir = undef;
}
else
{
}
unless (@tst = lstat("$dotdots/$dir"))
{
- warn "lstat($dotdots/$dir): $!";
- closedir(PARENT);
- return '';
+ # warn "lstat($dotdots/$dir): $!";
+ # Just because you can't lstat this directory
+ # doesn't mean you'll never find the right one.
+ # closedir(PARENT);
+ # return '';
}
}
while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] ||
$tst[1] != $pst[1]);
}
- $cwd = "$dir/$cwd";
+ $cwd = (defined $dir ? "$dir" : "" ) . "/$cwd" ;
closedir(PARENT);
- } while ($dir);
- chop($cwd); # drop the trailing /
+ } while (defined $dir);
+ chop($cwd) unless $cwd eq '/'; # drop the trailing /
$cwd;
}
#
# 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, $path);
local(*DIR);
- ($cdev, $cino) = stat('.');
+ my($orig_cdev, $orig_cino) = stat('.');
+ ($cdev, $cino) = ($orig_cdev, $orig_cino);
for (;;) {
my $direntry;
($odev, $oino) = ($cdev, $cino);
- chdir('..');
+ chdir('..') || return undef;
($cdev, $cino) = stat('.');
last if $odev == $cdev && $oino == $cino;
- opendir(DIR, '.');
+ opendir(DIR, '.') || return undef;
for (;;) {
$direntry = readdir(DIR);
+ last unless defined $direntry;
next if $direntry eq '.';
next if $direntry eq '..';
- last unless defined $direntry;
($tdev, $tino) = lstat($direntry);
last unless $tdev != $odev || $tino != $oino;
}
closedir(DIR);
+ return undef unless defined $direntry; # should never happen
unshift(@path, $direntry);
}
- chdir($path = '/' . join('/', @path));
+ $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
+ chdir($path) || return undef;
+ ($cdev, $cino) = stat('.');
+ die "Unstable directory path, current directory changed unexpectedly"
+ if $cdev != $orig_cdev || $cino != $orig_cino;
$path;
}
my $chdir_init = 0;
sub chdir_init {
- if ($ENV{'PWD'} and $osname ne 'os2') {
+ if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'msdos') {
my($dd,$di) = stat('.');
my($pd,$pi) = stat($ENV{'PWD'});
if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {
$newdir =~ s|///*|/|g;
chdir_init() unless $chdir_init;
return 0 unless CORE::chdir $newdir;
- if ($osname eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} }
+ if ($^O eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} }
if ($newdir =~ m#^/#) {
$ENV{'PWD'} = $newdir;
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])
+ {
+ $dir = '';
+ }
+ else
+ {
+ do
+ {
+ unless (defined ($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]);
+ }
+ $cwd = "$dir/$cwd";
+ closedir(PARENT);
+ } while ($dir);
+ chop($cwd); # drop the trailing /
+ $cwd;
+}
+
+sub fast_abs_path {
+ my $cwd = getcwd();
+ my $path = shift || '.';
+ chdir($path) || croak "Cannot chdir to $path:$!";
+ my $realpath = getcwd();
+ chdir($cwd) || croak "Cannot chdir back to $cwd:$!";
+ $realpath;
+}
+
# --- PORTING SECTION ---
# VMS: $ENV{'DEFAULT'} points to default directory at all times
-# 08-Dec-1994 Charles Bailey bailey@genetics.upenn.edu
-# Note: Use of Cwd::getcwd() or Cwd::chdir() (but not Cwd::fastcwd())
-# 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
+# 06-Mar-1996 Charles Bailey bailey@genetics.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.
-# This does not apply to other systems (where only chdir() sets PWD).
sub _vms_cwd {
- return $ENV{'DEFAULT'}
+ return $ENV{'DEFAULT'};
}
-sub _vms_pwd {
- return $ENV{'PWD'} = $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'};
return $ENV{'PWD'};
}
-if ($osname eq 'VMS') {
-
- *cwd = \&_vms_pwd;
- *getcwd = \&_vms_pwd;
- *fastgetcwd = \&_vms_cwd;
+sub _win32_cwd {
+ $ENV{'PWD'} = Win32::GetCurrentDirectory();
+ $ENV{'PWD'} =~ s:\\:/:g ;
+ return $ENV{'PWD'};
}
-elsif ($osname eq 'NT') {
- *getcwd = \&cwd;
- *fastgetcwd = \&cwd;
+*_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd &&
+ defined &Win32::GetCurrentDirectory);
+
+*_NT_cwd = \&_os2_cwd unless defined &_NT_cwd;
+
+sub _msdos_cwd {
+ $ENV{'PWD'} = `command /c cd`;
+ chop $ENV{'PWD'};
+ $ENV{'PWD'} =~ s:\\:/:g ;
+ return $ENV{'PWD'};
}
-elsif ($osname eq 'os2') {
- *cwd = \&_os2_cwd;
- *getcwd = \&_os2_cwd;
- *fastgetcwd = \&_os2_cwd;
- *fastcwd = \&_os2_cwd;
+
+{
+ 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 'msdos') {
+ *cwd = \&_msdos_cwd;
+ *getcwd = \&_msdos_cwd;
+ *fastgetcwd = \&_msdos_cwd;
+ *fastcwd = \&_msdos_cwd;
+ *abs_path = \&fast_abs_path;
+ }
}
# package main; eval join('',<DATA>) || die $@; # quick test
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