Make Cwd more bulletproof in chrooted environments.

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

diff --git a/lib/Cwd.pm b/lib/Cwd.pm
index e3c4590..7279591 100644 (file)
--- a/lib/Cwd.pm
+++ b/lib/Cwd.pm
@@ -66,30 +66,38 @@ kept up to date if all packages which use chdir import it from Cwd.
 
 =cut
 
-## use strict;
+use strict;
 
 use Carp;
 
-$VERSION = '2.02';
+our $VERSION = '2.03';
 
-require Exporter;
-@ISA = qw(Exporter);
-@EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
-@EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);
+use base qw/ Exporter /;
+our @EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
+our @EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);
 
 
 # The 'natural and safe form' for UNIX (pwd may be setuid root)
 
 sub _backtick_pwd {
-    my $cwd;
-    chop($cwd = `pwd`);
+    my $cwd = `pwd`;
+    # `pwd` may fail e.g. if the disk is full
+    chomp($cwd) if defined $cwd;
     $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;
+unless(defined &cwd) {
+    # The pwd command is not available in some chroot(2)'ed environments
+    if(grep { -x "$_/pwd" } split(':', $ENV{PATH})) {
+       *cwd = \&_backtick_pwd;
+    }
+    else {
+       *cwd = \&getcwd;
+    }
+}
 
 
 # By Brandon S. Allbery
@@ -108,9 +116,6 @@ sub getcwd
 # 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, $path);
@@ -142,7 +147,7 @@ sub fastcwd {
     if ($^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 $path =~ /^(.*)$/;   # untaint
+    $path = $1 if $path =~ /^(.*)\z/s; # untaint
     CORE::chdir($path) || return undef;
     ($cdev, $cino) = stat('.');
     die "Unstable directory path, current directory changed unexpectedly"
@@ -159,7 +164,7 @@ sub fastcwd {
 my $chdir_init = 0;
 
 sub chdir_init {
-    if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos') {
+    if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos' and $^O ne 'MSWin32') {
        my($dd,$di) = stat('.');
        my($pd,$pi) = stat($ENV{'PWD'});
        if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {
@@ -167,10 +172,12 @@ sub chdir_init {
        }
     }
     else {
-       $ENV{'PWD'} = cwd();
+       my $wd = cwd();
+       $wd = Win32::GetFullPathName($wd) if $^O eq 'MSWin32';
+       $ENV{'PWD'} = $wd;
     }
     # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar)
-    if ($ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|) {
+    if ($^O ne 'MSWin32' and $ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|s) {
        my($pd,$pi) = stat($2);
        my($dd,$di) = stat($1);
        if (defined $pd and defined $dd and $di == $pi and $dd == $pd) {
@@ -181,13 +188,19 @@ sub chdir_init {
 }
 
 sub chdir {
-    my $newdir = shift || '';  # allow for no arg (chdir to HOME dir)
-    $newdir =~ s|///*|/|g;
+    my $newdir = @? ? shift : '';      # allow for no arg (chdir to HOME dir)
+    $newdir =~ s|///*|/|g unless $^O eq 'MSWin32';
     chdir_init() unless $chdir_init;
     return 0 unless CORE::chdir $newdir;
-    if ($^O eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} }
+    if ($^O eq 'VMS') {
+       return $ENV{'PWD'} = $ENV{'DEFAULT'}
+    }
+    elsif ($^O eq 'MSWin32') {
+       $ENV{'PWD'} = Win32::GetFullPathName($newdir);
+       return 1;
+    }
 
-    if ($newdir =~ m#^/#) {
+    if ($newdir =~ m#^/#s) {
        $ENV{'PWD'} = $newdir;
     } else {
        my @curdir = split(m#/#,$ENV{'PWD'});
@@ -266,7 +279,7 @@ sub abs_path
 
 sub fast_abs_path {
     my $cwd = getcwd();
-    my $path = shift || '.';
+    my $path = @_ ? shift : '.';
     CORE::chdir($path) || croak "Cannot chdir to $path:$!";
     my $realpath = getcwd();
     CORE::chdir($cwd)  || croak "Cannot chdir back to $cwd:$!";
@@ -335,12 +348,17 @@ sub _qnx_cwd {
 }
 
 sub _qnx_abs_path {
-    my $path = shift || '.';
+    my $path = @_ ? shift : '.';
     my $realpath=`/usr/bin/fullpath -t $path`;
     chop $realpath;
     return $realpath;
 }
 
+sub _epoc_cwd {
+    $ENV{'PWD'} = EPOC::getcwd();
+    return $ENV{'PWD'};
+}
+
 {
     no warnings;       # assignments trigger 'subroutine redefined' warning
 
@@ -389,6 +407,12 @@ sub _qnx_abs_path {
         *fastcwd       = \&cwd;
         *abs_path      = \&fast_abs_path;
     }
+    elsif ($^O eq 'epoc') {
+        *getcwd        = \&_epoc_cwd;
+        *fastgetcwd    = \&_epoc_cwd;
+        *fastcwd       = \&_epoc_cwd;
+        *abs_path      = \&fast_abs_path;
+    }
 }
 
 # package main; eval join('',<DATA>) || die $@;        # quick test