package Cwd;
require 5.000;
-require Exporter;
=head1 NAME
chdir "/tmp";
print $ENV{'PWD'};
+ use Cwd 'abs_path'; # aka realpath()
+ print abs_path($ENV{'PWD'});
+
+ use Cwd 'fast_abs_path';
+ print fast_abs_path($ENV{'PWD'});
+
=head1 DESCRIPTION
The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions
in Perl.
+The abs_path() function takes a single argument and returns the
+absolute pathname for that argument. It uses the same algorithm
+as getcwd(). (Actually, getcwd() is abs_path(".")) Symbolic links
+and relative-path components ("." and "..") are resolved to return
+the canonical pathname, just like realpath(3). Also callable as
+realpath().
+
The fastcwd() function looks the same as getcwd(), but runs faster.
-It's also more dangerous because you might conceivably chdir() out of a
-directory that you can't chdir() back into.
+It's also more dangerous because it might conceivably chdir() you out
+of a directory that it can't chdir() you back into. If fastcwd
+encounters a problem it will return undef but will probably leave you
+in a different directory. For a measure of extra security, if
+everything appears to have worked, the fastcwd() function will check
+that it leaves you in the same directory that it started in. If it has
+changed it will C<die> with the message "Unstable directory path,
+current directory changed unexpectedly". That should never happen.
+
+The fast_abs_path() function looks the same as abs_path(), but runs faster.
+And like fastcwd() is more dangerous.
The cwd() function looks the same as getcwd and fastgetcwd but is
implemented using the most natural and safe form for the current
architecture. For most systems it is identical to `pwd` (but without
-the trailing line terminator). It is recommended that cwd (or another
-*cwd() function) is used in I<all> code to ensure portability.
+the trailing line terminator).
+
+It is recommended that cwd (or another *cwd() function) is used in
+I<all> code to ensure portability.
If you ask to override your chdir() built-in function, then your PWD
environment variable will be kept up to date. (See
=cut
+## use strict;
+
+use Carp;
+
+$VERSION = '2.03';
+
+require Exporter;
@ISA = qw(Exporter);
@EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
-@EXPORT_OK = qw(chdir);
+@EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);
+
-# 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`);
$cwd;
-}
+}
# Since some ports may predefine cwd internally (e.g., NT)
# we take care not to override an existing definition for cwd().
sub getcwd
{
- my($dotdots, $cwd, @pst, @cst, $dir, @tst);
-
- unless (@cst = stat('.'))
- {
- warn "stat(.): $!";
- return '';
- }
- $cwd = '';
- $dotdots = '';
- do
- {
- $dotdots .= '/' if $dotdots;
- $dotdots .= '..';
- @pst = @cst;
- unless (opendir(PARENT, $dotdots))
- {
- warn "opendir($dotdots): $!";
- return '';
- }
- unless (@cst = stat($dotdots))
- {
- warn "stat($dotdots): $!";
- closedir(PARENT);
- return '';
- }
- if ($pst[0] == $cst[0] && $pst[1] == $cst[1])
- {
- $dir = '';
- }
- else
- {
- do
- {
- unless (defined ($dir = readdir(PARENT)))
- {
- warn "readdir($dotdots): $!";
- closedir(PARENT);
- return '';
- }
- unless (@tst = lstat("$dotdots/$dir"))
- {
- # warn "lstat($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/$cwd";
- closedir(PARENT);
- } while ($dir);
- chop($cwd) unless $cwd eq '/'; # drop the trailing /
- $cwd;
+ abs_path('.');
}
-
-
# By John Bazik
#
# Usage: $cwd = &fastcwd;
#
# This is a faster version of getcwd. It's also more dangerous because
# you might chdir out of a directory that you can't chdir back into.
-
+
sub fastcwd {
my($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, $cino);
- chdir('..');
+ CORE::chdir('..') || return undef;
($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));
+ $path = '/' . join('/', @path);
+ if ($^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;
}
my $chdir_init = 0;
sub chdir_init {
- if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'msdos') {
+ if ($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) {
$ENV{'PWD'} = cwd();
}
# Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar)
- if ($ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|) {
+ if ($ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|s) {
my($pd,$pi) = stat($2);
my($dd,$di) = stat($1);
if (defined $pd and defined $dd and $di == $pi and $dd == $pd) {
return 0 unless CORE::chdir $newdir;
if ($^O eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} }
- if ($newdir =~ m#^/#) {
+ if ($newdir =~ m#^/#s) {
$ENV{'PWD'} = $newdir;
} else {
my @curdir = split(m#/#,$ENV{'PWD'});
}
+# By Jeff "japhy" Pinyan (07/23/2000)
+# usage: abs_path(PATHNAME)
+# see the docs
+
+sub abs_path {
+ my $base = @_ ? $_[0] : ".";
+ my $path = "";
+ my $file;
+
+ do {
+ my @devino = (stat($base))[0,1] or
+ carp("stat($base): $!"), return;
+
+ $base .= "/..";
+
+ opendir PREV, $base or carp("opendir($base): $!"), return;
+ while (defined($file = readdir PREV)) {
+ next if $file eq "." or $file eq "..";
+ my @entry = (lstat("$base/$file"))[0,1] or
+ carp("lstat($base/$file): $!"), return;
+ last if $devino[0] == $entry[0] and $devino[1] == $entry[1];
+ }
+ closedir PREV;
+
+ $path = (defined $file and $file) . "/$path";
+ } while defined $file;
+
+ length($path) > 1 and chop $path;
+ return $path;
+}
+
+
+# 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 $path = shift || '.';
+ CORE::chdir($path) || croak "Cannot chdir to $path:$!";
+ my $realpath = getcwd();
+ CORE::chdir($cwd) || croak "Cannot chdir back to $cwd:$!";
+ $realpath;
+}
+
+# added function alias to follow principle of least surprise
+# based on previous aliasing. --tchrist 27-Jan-00
+*fast_realpath = \&fast_abs_path;
+
+
# --- PORTING SECTION ---
# VMS: $ENV{'DEFAULT'} points to default directory at all times
-# 06-Mar-1996 Charles Bailey bailey@genetics.upenn.edu
+# 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
+# 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'}
+ 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'};
return $ENV{'PWD'};
}
-sub _msdos_cwd {
- $ENV{'PWD'} = `command /c cd`;
- chop $ENV{'PWD'};
+sub _win32_cwd {
+ $ENV{'PWD'} = Win32::GetCwd();
$ENV{'PWD'} =~ s:\\:/:g ;
return $ENV{'PWD'};
}
-my($oldw) = $^W;
-$^W = 0; # assignments trigger 'subroutine redefined' warning
-if ($^O eq 'VMS') {
+*_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd &&
+ defined &Win32::GetCwd);
+
+*_NT_cwd = \&_os2_cwd unless defined &_NT_cwd;
- *cwd = \&_vms_cwd;
- *getcwd = \&_vms_cwd;
- *fastcwd = \&_vms_cwd;
- *fastgetcwd = \&_vms_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 $ENV{'PWD'};
}
-elsif ($^O eq 'NT' or $^O eq 'MSWin32') {
- # We assume that &_NT_cwd is defined as an XSUB or in the core.
- *getcwd = \&_NT_cwd;
- *fastcwd = \&_NT_cwd;
- *fastgetcwd = \&_NT_cwd;
+sub _qnx_cwd {
+ $ENV{'PWD'} = `/usr/bin/fullpath -t`;
+ chop $ENV{'PWD'};
+ return $ENV{'PWD'};
}
-elsif ($^O eq 'os2') {
- # sys_cwd may keep the builtin command
- *cwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
- *getcwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
- *fastgetcwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
- *fastcwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
+
+sub _qnx_abs_path {
+ my $path = shift || '.';
+ my $realpath=`/usr/bin/fullpath -t $path`;
+ chop $realpath;
+ return $realpath;
}
-elsif ($^O eq 'msdos') {
- *cwd = \&_msdos_cwd;
- *getcwd = \&_msdos_cwd;
- *fastgetcwd = \&_msdos_cwd;
- *fastcwd = \&_msdos_cwd;
+
+{
+ no warnings; # 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;
+ }
+ elsif ($^O eq 'cygwin') {
+ *getcwd = \&cwd;
+ *fastgetcwd = \&cwd;
+ *fastcwd = \&cwd;
+ *abs_path = \&fast_abs_path;
+ }
}
-$^W = $oldw;
# package main; eval join('',<DATA>) || die $@; # quick test