package Cwd;
-require 5.000;
+require 5.6.0;
=head1 NAME
=head1 SYNOPSIS
use Cwd;
- $dir = cwd;
+ my $dir = getcwd;
- use Cwd;
- $dir = getcwd;
+ use Cwd 'abs_path';
+ my $abs_path = abs_path($file);
- use Cwd;
- $dir = fastcwd;
+=head1 DESCRIPTION
- use Cwd;
- $dir = fastgetcwd;
+This module provides functions for determining the pathname of the
+current working directory. It is recommended that getcwd (or another
+*cwd() function) be used in I<all> code to ensure portability.
- use Cwd 'chdir';
- chdir "/tmp";
- print $ENV{'PWD'};
+By default, it exports the functions cwd(), getcwd(), fastcwd(), and
+fastgetcwd() into the caller's namespace.
- use Cwd 'abs_path'; # aka realpath()
- print abs_path($ENV{'PWD'});
- use Cwd 'fast_abs_path';
- print fast_abs_path($ENV{'PWD'});
+=head2 getcwd and friends
-=head1 DESCRIPTION
+Each of these functions are called without arguments and return the
+absolute path of the current working directory.
-This module provides functions for determining the pathname of the
-current working directory. By default, it exports the functions
-cwd(), getcwd(), fastcwd(), and fastgetcwd() into the caller's
-namespace. Each of these functions are called without arguments and
-return the absolute path of the current working directory. It is
-recommended that cwd (or another *cwd() function) be used in I<all>
-code to ensure portability.
-
-The cwd() is the most natural and safe form for the current
-architecture. For most systems it is identical to `pwd` (but without
-the trailing line terminator).
-
-The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions
-in Perl.
-
-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.
+=over 4
+
+=item getcwd
+
+ my $cwd = getcwd();
+
+Returns the current working directory.
+
+Re-implements the getcwd(3) (or getwd(3)) functions in Perl.
+
+=item cwd
+
+ my $cwd = cwd();
+
+The cwd() is the most natural form for the current architecture. For
+most systems it is identical to `pwd` (but without the trailing line
+terminator).
+
+Unfortunately, cwd() tends to break if called under taint mode.
+
+=item fastcwd
+
+ my $cwd = fastcwd();
+
+A more dangerous version of getcwd(), but potentially faster.
+
+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.
+
+=item fastgetcwd
+
+ my $cwd = fastgetcwd();
The fastgetcwd() function is provided as a synonym for cwd().
-The abs_path() function takes a single argument and returns the
-absolute pathname for that argument. It uses the same algorithm as
-getcwd(). (Actually, getcwd() is abs_path(".")) Symbolic links and
-relative-path components ("." and "..") are resolved to return the
-canonical pathname, just like realpath(3). This function is also
-callable as realpath().
+=back
+
+
+=head2 abs_path and friends
+
+These functions are exported only on request. They each take a single
+argument and return the absolute pathname for it.
+
+=over 4
+
+=item abs_path
+
+ my $abs_path = abs_path($file);
+
+Uses the same algorithm as getcwd(). Symbolic links and relative-path
+components ("." and "..") are resolved to return the canonical
+pathname, just like realpath(3).
+
+=item realpath
+
+ my $abs_path = realpath($file);
+
+A synonym for abs_path().
+
+=item fast_abs_path
+
+ my $abs_path = abs_path($file);
-The fast_abs_path() function looks the same as abs_path() but runs
-faster and, like fastcwd(), is more dangerous.
+A more dangerous, but potentially faster version of abs_path.
-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.
+=back
+
+=head2 $ENV{PWD}
+
+If you ask to override your chdir() built-in function,
+
+ use Cwd qw(chdir);
+
+then your PWD environment variable will be kept up to date. Note that
+it will only be kept up to date if all packages which use chdir import
+it from Cwd.
+
+
+=head1 NOTES
+
+=over 4
+
+=item *
+
+Since the path seperators are different on some operating systems ('/'
+on Unix, ':' on MacPerl, etc...) we recommend you use the File::Spec
+modules wherever portability is a concern.
+
+=item *
+
+Actually, on Mac OS, the C<getcwd()>, C<fastgetcwd()> and C<fastcwd()>
+functions are all aliases for the C<cwd()> function, which, on Mac OS,
+calls `pwd`. Likewise, the C<abs_path()> function is an alias for
+C<fast_abs_path()>.
+
+=back
+
+=head1 SEE ALSO
+
+L<File::chdir>
=cut
use Carp;
-our $VERSION = '2.04';
+our $VERSION = '2.06';
use base qw/ Exporter /;
our @EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
our @EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);
-# Indicates if the XS portion has been loaded or not
-my $Booted = 0;
+# sys_cwd may keep the builtin command
+
+# All the functionality of this module may provided by builtins,
+# there is no sense to process the rest of the file.
+# The best choice may be to have this in BEGIN, but how to return from BEGIN?
+
+if ($^O eq 'os2' && defined &sys_cwd && defined &sys_abspath) {
+ local $^W = 0;
+ *cwd = \&sys_cwd;
+ *getcwd = \&cwd;
+ *fastgetcwd = \&cwd;
+ *fastcwd = \&cwd;
+ *abs_path = \&sys_abspath;
+ *fast_abs_path = \&abs_path;
+ *realpath = \&abs_path;
+ *fast_realpath = \&abs_path;
+ return 1;
+}
-# The 'natural and safe form' for UNIX (pwd may be setuid root)
+eval {
+ require XSLoader;
+ undef *Cwd::fastcwd; # avoid redefinition warning
+ XSLoader::load('Cwd');
+};
+
+
+# Find the pwd command in the expected locations. We assume these
+# are safe. This prevents _backtick_pwd() consulting $ENV{PATH}
+# so everything works under taint mode.
+my $pwd_cmd;
+foreach my $try (qw(/bin/pwd /usr/bin/pwd)) {
+ if( -x $try ) {
+ $pwd_cmd = $try;
+ last;
+ }
+}
+$pwd_cmd ||= 'pwd';
+# The 'natural and safe form' for UNIX (pwd may be setuid root)
sub _backtick_pwd {
- my $cwd = `pwd`;
+ my $cwd = `$pwd_cmd`;
# `pwd` may fail e.g. if the disk is full
chomp($cwd) if defined $cwd;
$cwd;
abs_path('.');
}
-# Now a callout to an XSUB. We have to delay booting of the XSUB
-# until the first time fastcwd is called since Cwd::cwd is needed in the
-# building of perl when dynamic loading may be unavailable
+
+# By John Bazik
+#
+# Usage: $cwd = &fastcwd;
+#
+# This is a faster version of getcwd. It's also more dangerous because
+# you might chdir out of a directory that you can't chdir back into.
+
sub fastcwd {
- unless ($Booted) {
- require XSLoader;
- XSLoader::load("Cwd");
- ++$Booted;
+ my($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);
}
- return &Cwd::_fastcwd;
+ $path = '/' . join('/', @path);
+ if ($^O eq 'apollo') { $path = "/".$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 $path =~ /^(.*)\z/s; # untaint
+ CORE::chdir($path) || return undef;
+ ($cdev, $cino) = stat('.');
+ die "Unstable directory path, current directory changed unexpectedly"
+ if $cdev != $orig_cdev || $cino != $orig_cino;
+ $path;
}
1;
}
-# Now a callout to an XSUB
-sub abs_path
+
+# In case the XS version doesn't load.
+*abs_path = \&_perl_abs_path unless defined &abs_path;
+sub _perl_abs_path
{
- unless ($Booted) {
- require XSLoader;
- XSLoader::load("Cwd");
- ++$Booted;
+ my $start = @_ ? shift : '.';
+ my($dotdots, $cwd, @pst, @cst, $dir, @tst);
+
+ unless (@cst = stat( $start ))
+ {
+ carp "stat($start): $!";
+ return '';
}
- return &Cwd::_abs_path(@_);
+ $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;
}
+
# added function alias for those of us more
# used to the libc function. --tchrist 27-Jan-00
*realpath = \&abs_path;
sub fast_abs_path {
my $cwd = getcwd();
- my $path = @_ ? shift : '.';
+ require File::Spec;
+ my $path = @_ ? shift : File::Spec->curdir;
CORE::chdir($path) || croak "Cannot chdir to $path:$!";
my $realpath = getcwd();
CORE::chdir($cwd) || croak "Cannot chdir back to $cwd:$!";
*fastcwd = \&_dos_cwd;
*abs_path = \&fast_abs_path;
}
- elsif ($^O eq 'qnx') {
+ elsif ($^O =~ m/^(?:qnx|nto)$/ ) {
*cwd = \&_qnx_cwd;
*getcwd = \&_qnx_cwd;
*fastgetcwd = \&_qnx_cwd;
}
}
-# 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";
https://perl5.git.perl.org / perl5.git / blobdiff