2 $VERSION = $VERSION = '2.15';
6 Cwd - get pathname of current working directory
14 my $abs_path = abs_path($file);
18 This module provides functions for determining the pathname of the
19 current working directory. It is recommended that getcwd (or another
20 *cwd() function) be used in I<all> code to ensure portability.
22 By default, it exports the functions cwd(), getcwd(), fastcwd(), and
23 fastgetcwd() into the caller's namespace.
26 =head2 getcwd and friends
28 Each of these functions are called without arguments and return the
29 absolute path of the current working directory.
37 Returns the current working directory.
39 Re-implements the getcwd(3) (or getwd(3)) functions in Perl.
45 The cwd() is the most natural form for the current architecture. For
46 most systems it is identical to `pwd` (but without the trailing line
53 A more dangerous version of getcwd(), but potentially faster.
55 It might conceivably chdir() you out of a directory that it can't
56 chdir() you back into. If fastcwd encounters a problem it will return
57 undef but will probably leave you in a different directory. For a
58 measure of extra security, if everything appears to have worked, the
59 fastcwd() function will check that it leaves you in the same directory
60 that it started in. If it has changed it will C<die> with the message
61 "Unstable directory path, current directory changed
62 unexpectedly". That should never happen.
66 my $cwd = fastgetcwd();
68 The fastgetcwd() function is provided as a synonym for cwd().
73 =head2 abs_path and friends
75 These functions are exported only on request. They each take a single
76 argument and return the absolute pathname for it. If no argument is
77 given they'll use the current working directory.
83 my $abs_path = abs_path($file);
85 Uses the same algorithm as getcwd(). Symbolic links and relative-path
86 components ("." and "..") are resolved to return the canonical
87 pathname, just like realpath(3).
91 my $abs_path = realpath($file);
93 A synonym for abs_path().
97 my $abs_path = fast_abs_path($file);
99 A more dangerous, but potentially faster version of abs_path.
105 If you ask to override your chdir() built-in function,
109 then your PWD environment variable will be kept up to date. Note that
110 it will only be kept up to date if all packages which use chdir import
120 Since the path seperators are different on some operating systems ('/'
121 on Unix, ':' on MacPerl, etc...) we recommend you use the File::Spec
122 modules wherever portability is a concern.
126 Actually, on Mac OS, the C<getcwd()>, C<fastgetcwd()> and C<fastcwd()>
127 functions are all aliases for the C<cwd()> function, which, on Mac OS,
128 calls `pwd`. Likewise, the C<abs_path()> function is an alias for
135 Originally by the perl5-porters.
137 Now maintained by Ken Williams <KWILLIAMS@cpan.org>
147 use vars qw(@ISA @EXPORT @EXPORT_OK);
149 @ISA = qw/ Exporter /;
150 @EXPORT = qw(cwd getcwd fastcwd fastgetcwd);
151 @EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath);
153 # sys_cwd may keep the builtin command
155 # All the functionality of this module may provided by builtins,
156 # there is no sense to process the rest of the file.
157 # The best choice may be to have this in BEGIN, but how to return from BEGIN?
162 *cwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd;
167 *fast_abs_path = \&sys_abspath if defined &sys_abspath;
168 *abs_path = \&fast_abs_path;
169 *realpath = \&fast_abs_path;
170 *fast_realpath = \&fast_abs_path;
178 XSLoader::load('Cwd');
182 # Find the pwd command in the expected locations. We assume these
183 # are safe. This prevents _backtick_pwd() consulting $ENV{PATH}
184 # so everything works under taint mode.
186 foreach my $try ('/bin/pwd',
188 '/QOpenSys/bin/pwd', # OS/400 PASE.
197 # Isn't this wrong? _backtick_pwd() will fail if somenone has
198 # pwd in their path but it is not /bin/pwd or /usr/bin/pwd?
199 # See [perl #16774]. --jhi
204 sub _carp { require Carp; Carp::carp(@_) }
205 sub _croak { require Carp; Carp::croak(@_) }
207 # The 'natural and safe form' for UNIX (pwd may be setuid root)
209 local @ENV{qw(PATH IFS CDPATH ENV BASH_ENV)};
210 my $cwd = `$pwd_cmd`;
211 # Belt-and-suspenders in case someone said "undef $/".
213 # `pwd` may fail e.g. if the disk is full
214 chomp($cwd) if defined $cwd;
218 # Since some ports may predefine cwd internally (e.g., NT)
219 # we take care not to override an existing definition for cwd().
221 unless(defined &cwd) {
222 # The pwd command is not available in some chroot(2)'ed environments
223 if( $^O eq 'MacOS' || (defined $ENV{PATH} &&
224 grep { -x "$_/pwd" } split(':', $ENV{PATH})) )
226 *cwd = \&_backtick_pwd;
233 # set a reasonable (and very safe) default for fastgetcwd, in case it
234 # isn't redefined later (20001212 rspier)
237 # By Brandon S. Allbery
239 # Usage: $cwd = getcwd();
249 # Usage: $cwd = &fastcwd;
251 # This is a faster version of getcwd. It's also more dangerous because
252 # you might chdir out of a directory that you can't chdir back into.
255 my($odev, $oino, $cdev, $cino, $tdev, $tino);
259 my($orig_cdev, $orig_cino) = stat('.');
260 ($cdev, $cino) = ($orig_cdev, $orig_cino);
263 ($odev, $oino) = ($cdev, $cino);
264 CORE::chdir('..') || return undef;
265 ($cdev, $cino) = stat('.');
266 last if $odev == $cdev && $oino == $cino;
267 opendir(DIR, '.') || return undef;
269 $direntry = readdir(DIR);
270 last unless defined $direntry;
271 next if $direntry eq '.';
272 next if $direntry eq '..';
274 ($tdev, $tino) = lstat($direntry);
275 last unless $tdev != $odev || $tino != $oino;
278 return undef unless defined $direntry; # should never happen
279 unshift(@path, $direntry);
281 $path = '/' . join('/', @path);
282 if ($^O eq 'apollo') { $path = "/".$path; }
283 # At this point $path may be tainted (if tainting) and chdir would fail.
284 # Untaint it then check that we landed where we started.
285 $path =~ /^(.*)\z/s # untaint
286 && CORE::chdir($1) or return undef;
287 ($cdev, $cino) = stat('.');
288 die "Unstable directory path, current directory changed unexpectedly"
289 if $cdev != $orig_cdev || $cino != $orig_cino;
294 # Keeps track of current working directory in PWD environment var
302 if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos' and $^O ne 'MSWin32') {
303 my($dd,$di) = stat('.');
304 my($pd,$pi) = stat($ENV{'PWD'});
305 if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) {
311 $wd = Win32::GetFullPathName($wd) if $^O eq 'MSWin32';
314 # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar)
315 if ($^O ne 'MSWin32' and $ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|s) {
316 my($pd,$pi) = stat($2);
317 my($dd,$di) = stat($1);
318 if (defined $pd and defined $dd and $di == $pi and $dd == $pd) {
326 my $newdir = @_ ? shift : ''; # allow for no arg (chdir to HOME dir)
327 $newdir =~ s|///*|/|g unless $^O eq 'MSWin32';
328 chdir_init() unless $chdir_init;
330 if ($^O eq 'MSWin32') {
331 # get the full path name *before* the chdir()
332 $newpwd = Win32::GetFullPathName($newdir);
335 return 0 unless CORE::chdir $newdir;
338 return $ENV{'PWD'} = $ENV{'DEFAULT'}
340 elsif ($^O eq 'MacOS') {
341 return $ENV{'PWD'} = cwd();
343 elsif ($^O eq 'MSWin32') {
344 $ENV{'PWD'} = $newpwd;
348 if ($newdir =~ m#^/#s) {
349 $ENV{'PWD'} = $newdir;
351 my @curdir = split(m#/#,$ENV{'PWD'});
352 @curdir = ('') unless @curdir;
354 foreach $component (split(m#/#, $newdir)) {
355 next if $component eq '.';
356 pop(@curdir),next if $component eq '..';
357 push(@curdir,$component);
359 $ENV{'PWD'} = join('/',@curdir) || '/';
365 # In case the XS version doesn't load.
366 *abs_path = \&_perl_abs_path unless defined &abs_path;
369 my $start = @_ ? shift : '.';
370 my($dotdots, $cwd, @pst, @cst, $dir, @tst);
372 unless (@cst = stat( $start ))
374 _carp("stat($start): $!");
384 unless (opendir(PARENT, $dotdots))
386 _carp("opendir($dotdots): $!");
389 unless (@cst = stat($dotdots))
391 _carp("stat($dotdots): $!");
395 if ($pst[0] == $cst[0] && $pst[1] == $cst[1])
403 unless (defined ($dir = readdir(PARENT)))
405 _carp("readdir($dotdots): $!");
409 $tst[0] = $pst[0]+1 unless (@tst = lstat("$dotdots/$dir"))
411 while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] ||
414 $cwd = (defined $dir ? "$dir" : "" ) . "/$cwd" ;
416 } while (defined $dir);
417 chop($cwd) unless $cwd eq '/'; # drop the trailing /
422 # added function alias for those of us more
423 # used to the libc function. --tchrist 27-Jan-00
424 *realpath = \&abs_path;
430 my $path = @_ ? shift : ($Curdir ||= File::Spec->curdir);
432 # Detaint else we'll explode in taint mode. This is safe because
433 # we're not doing anything dangerous with it.
434 ($path) = $path =~ /(.*)/;
435 ($cwd) = $cwd =~ /(.*)/;
437 if (!CORE::chdir($path)) {
438 _croak("Cannot chdir to $path: $!");
440 my $realpath = getcwd();
441 if (! ((-d $cwd) && (CORE::chdir($cwd)))) {
442 _croak("Cannot chdir back to $cwd: $!");
447 # added function alias to follow principle of least surprise
448 # based on previous aliasing. --tchrist 27-Jan-00
449 *fast_realpath = \&fast_abs_path;
452 # --- PORTING SECTION ---
454 # VMS: $ENV{'DEFAULT'} points to default directory at all times
455 # 06-Mar-1996 Charles Bailey bailey@newman.upenn.edu
456 # Note: Use of Cwd::chdir() causes the logical name PWD to be defined
457 # in the process logical name table as the default device and directory
458 # seen by Perl. This may not be the same as the default device
459 # and directory seen by DCL after Perl exits, since the effects
460 # the CRTL chdir() function persist only until Perl exits.
463 return $ENV{'DEFAULT'};
467 return $ENV{'DEFAULT'} unless @_;
468 my $path = VMS::Filespec::pathify($_[0]);
471 _croak("Invalid path name $_[0]")
473 return VMS::Filespec::rmsexpand($path);
477 $ENV{'PWD'} = `cmd /c cd`;
479 $ENV{'PWD'} =~ s:\\:/:g ;
484 $ENV{'PWD'} = Win32::GetCwd();
485 $ENV{'PWD'} =~ s:\\:/:g ;
489 *_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd &&
490 defined &Win32::GetCwd);
492 *_NT_cwd = \&_os2_cwd unless defined &_NT_cwd;
495 if (!defined &Dos::GetCwd) {
496 $ENV{'PWD'} = `command /c cd`;
498 $ENV{'PWD'} =~ s:\\:/:g ;
500 $ENV{'PWD'} = Dos::GetCwd();
506 local $ENV{PATH} = '';
507 local $ENV{CDPATH} = '';
508 local $ENV{ENV} = '';
509 $ENV{'PWD'} = `/usr/bin/fullpath -t`;
515 local $ENV{PATH} = '';
516 local $ENV{CDPATH} = '';
517 local $ENV{ENV} = '';
518 my $path = @_ ? shift : '.';
521 open(REALPATH, '-|', '/usr/bin/fullpath', '-t', $path) or
522 die "Can't open /usr/bin/fullpath: $!";
523 my $realpath = <REALPATH>;
530 $ENV{'PWD'} = EPOC::getcwd();
535 no warnings; # assignments trigger 'subroutine redefined' warning
539 *getcwd = \&_vms_cwd;
540 *fastcwd = \&_vms_cwd;
541 *fastgetcwd = \&_vms_cwd;
542 *abs_path = \&_vms_abs_path;
543 *fast_abs_path = \&_vms_abs_path;
545 elsif ($^O eq 'NT' or $^O eq 'MSWin32') {
546 # We assume that &_NT_cwd is defined as an XSUB or in the core.
549 *fastcwd = \&_NT_cwd;
550 *fastgetcwd = \&_NT_cwd;
551 *abs_path = \&fast_abs_path;
552 *realpath = \&fast_abs_path;
554 elsif ($^O eq 'dos') {
556 *getcwd = \&_dos_cwd;
557 *fastgetcwd = \&_dos_cwd;
558 *fastcwd = \&_dos_cwd;
559 *abs_path = \&fast_abs_path;
561 elsif ($^O =~ m/^(?:qnx|nto)$/ ) {
563 *getcwd = \&_qnx_cwd;
564 *fastgetcwd = \&_qnx_cwd;
565 *fastcwd = \&_qnx_cwd;
566 *abs_path = \&_qnx_abs_path;
567 *fast_abs_path = \&_qnx_abs_path;
569 elsif ($^O eq 'cygwin') {
573 *abs_path = \&fast_abs_path;
574 *realpath = \&abs_path;
576 elsif ($^O eq 'epoc') {
578 *getcwd = \&_epoc_cwd;
579 *fastgetcwd = \&_epoc_cwd;
580 *fastcwd = \&_epoc_cwd;
581 *abs_path = \&fast_abs_path;
583 elsif ($^O eq 'MacOS') {
587 *abs_path = \&fast_abs_path;