1package Cwd; 2 3=head1 NAME 4 5Cwd - get pathname of current working directory 6 7=head1 SYNOPSIS 8 9 use Cwd; 10 my $dir = getcwd; 11 12 use Cwd 'abs_path'; 13 my $abs_path = abs_path($file); 14 15=head1 DESCRIPTION 16 17This module provides functions for determining the pathname of the 18current working directory. It is recommended that getcwd (or another 19*cwd() function) be used in I<all> code to ensure portability. 20 21By default, it exports the functions cwd(), getcwd(), fastcwd(), and 22fastgetcwd() (and, on Win32, getdcwd()) into the caller's namespace. 23 24 25=head2 getcwd and friends 26 27Each of these functions are called without arguments and return the 28absolute path of the current working directory. 29 30=over 4 31 32=item getcwd 33 34 my $cwd = getcwd(); 35 36Returns the current working directory. 37 38Exposes the POSIX function getcwd(3) or re-implements it if it's not 39available. 40 41=item cwd 42 43 my $cwd = cwd(); 44 45The cwd() is the most natural form for the current architecture. For 46most systems it is identical to `pwd` (but without the trailing line 47terminator). 48 49=item fastcwd 50 51 my $cwd = fastcwd(); 52 53A more dangerous version of getcwd(), but potentially faster. 54 55It might conceivably chdir() you out of a directory that it can't 56chdir() you back into. If fastcwd encounters a problem it will return 57undef but will probably leave you in a different directory. For a 58measure of extra security, if everything appears to have worked, the 59fastcwd() function will check that it leaves you in the same directory 60that it started in. If it has changed it will C<die> with the message 61"Unstable directory path, current directory changed 62unexpectedly". That should never happen. 63 64=item fastgetcwd 65 66 my $cwd = fastgetcwd(); 67 68The fastgetcwd() function is provided as a synonym for cwd(). 69 70=item getdcwd 71 72 my $cwd = getdcwd(); 73 my $cwd = getdcwd('C:'); 74 75The getdcwd() function is also provided on Win32 to get the current working 76directory on the specified drive, since Windows maintains a separate current 77working directory for each drive. If no drive is specified then the current 78drive is assumed. 79 80This function simply calls the Microsoft C library _getdcwd() function. 81 82=back 83 84 85=head2 abs_path and friends 86 87These functions are exported only on request. They each take a single 88argument and return the absolute pathname for it. If no argument is 89given they'll use the current working directory. 90 91=over 4 92 93=item abs_path 94 95 my $abs_path = abs_path($file); 96 97Uses the same algorithm as getcwd(). Symbolic links and relative-path 98components ("." and "..") are resolved to return the canonical 99pathname, just like realpath(3). 100 101=item realpath 102 103 my $abs_path = realpath($file); 104 105A synonym for abs_path(). 106 107=item fast_abs_path 108 109 my $abs_path = fast_abs_path($file); 110 111A more dangerous, but potentially faster version of abs_path. 112 113=back 114 115=head2 $ENV{PWD} 116 117If you ask to override your chdir() built-in function, 118 119 use Cwd qw(chdir); 120 121then your PWD environment variable will be kept up to date. Note that 122it will only be kept up to date if all packages which use chdir import 123it from Cwd. 124 125 126=head1 NOTES 127 128=over 4 129 130=item * 131 132Since the path seperators are different on some operating systems ('/' 133on Unix, ':' on MacPerl, etc...) we recommend you use the File::Spec 134modules wherever portability is a concern. 135 136=item * 137 138Actually, on Mac OS, the C<getcwd()>, C<fastgetcwd()> and C<fastcwd()> 139functions are all aliases for the C<cwd()> function, which, on Mac OS, 140calls `pwd`. Likewise, the C<abs_path()> function is an alias for 141C<fast_abs_path()>. 142 143=back 144 145=head1 AUTHOR 146 147Originally by the perl5-porters. 148 149Maintained by Ken Williams <KWILLIAMS@cpan.org> 150 151=head1 COPYRIGHT 152 153Copyright (c) 2004 by the Perl 5 Porters. All rights reserved. 154 155This program is free software; you can redistribute it and/or modify 156it under the same terms as Perl itself. 157 158Portions of the C code in this library are copyright (c) 1994 by the 159Regents of the University of California. All rights reserved. The 160license on this code is compatible with the licensing of the rest of 161the distribution - please see the source code in F<Cwd.xs> for the 162details. 163 164=head1 SEE ALSO 165 166L<File::chdir> 167 168=cut 169 170use strict; 171use Exporter; 172use vars qw(@ISA @EXPORT @EXPORT_OK $VERSION); 173 174$VERSION = '3.24'; 175 176@ISA = qw/ Exporter /; 177@EXPORT = qw(cwd getcwd fastcwd fastgetcwd); 178push @EXPORT, qw(getdcwd) if $^O eq 'MSWin32'; 179@EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath); 180 181# sys_cwd may keep the builtin command 182 183# All the functionality of this module may provided by builtins, 184# there is no sense to process the rest of the file. 185# The best choice may be to have this in BEGIN, but how to return from BEGIN? 186 187if ($^O eq 'os2') { 188 local $^W = 0; 189 190 *cwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd; 191 *getcwd = \&cwd; 192 *fastgetcwd = \&cwd; 193 *fastcwd = \&cwd; 194 195 *fast_abs_path = \&sys_abspath if defined &sys_abspath; 196 *abs_path = \&fast_abs_path; 197 *realpath = \&fast_abs_path; 198 *fast_realpath = \&fast_abs_path; 199 200 return 1; 201} 202 203# If loading the XS stuff doesn't work, we can fall back to pure perl 204eval { 205 if ( $] >= 5.006 ) { 206 require XSLoader; 207 XSLoader::load( __PACKAGE__, $VERSION ); 208 } else { 209 require DynaLoader; 210 push @ISA, 'DynaLoader'; 211 __PACKAGE__->bootstrap( $VERSION ); 212 } 213}; 214 215# Must be after the DynaLoader stuff: 216$VERSION = eval $VERSION; 217 218# Big nasty table of function aliases 219my %METHOD_MAP = 220 ( 221 VMS => 222 { 223 cwd => '_vms_cwd', 224 getcwd => '_vms_cwd', 225 fastcwd => '_vms_cwd', 226 fastgetcwd => '_vms_cwd', 227 abs_path => '_vms_abs_path', 228 fast_abs_path => '_vms_abs_path', 229 }, 230 231 MSWin32 => 232 { 233 # We assume that &_NT_cwd is defined as an XSUB or in the core. 234 cwd => '_NT_cwd', 235 getcwd => '_NT_cwd', 236 fastcwd => '_NT_cwd', 237 fastgetcwd => '_NT_cwd', 238 abs_path => 'fast_abs_path', 239 realpath => 'fast_abs_path', 240 }, 241 242 dos => 243 { 244 cwd => '_dos_cwd', 245 getcwd => '_dos_cwd', 246 fastgetcwd => '_dos_cwd', 247 fastcwd => '_dos_cwd', 248 abs_path => 'fast_abs_path', 249 }, 250 251 qnx => 252 { 253 cwd => '_qnx_cwd', 254 getcwd => '_qnx_cwd', 255 fastgetcwd => '_qnx_cwd', 256 fastcwd => '_qnx_cwd', 257 abs_path => '_qnx_abs_path', 258 fast_abs_path => '_qnx_abs_path', 259 }, 260 261 cygwin => 262 { 263 getcwd => 'cwd', 264 fastgetcwd => 'cwd', 265 fastcwd => 'cwd', 266 abs_path => 'fast_abs_path', 267 realpath => 'fast_abs_path', 268 }, 269 270 epoc => 271 { 272 cwd => '_epoc_cwd', 273 getcwd => '_epoc_cwd', 274 fastgetcwd => '_epoc_cwd', 275 fastcwd => '_epoc_cwd', 276 abs_path => 'fast_abs_path', 277 }, 278 279 MacOS => 280 { 281 getcwd => 'cwd', 282 fastgetcwd => 'cwd', 283 fastcwd => 'cwd', 284 abs_path => 'fast_abs_path', 285 }, 286 ); 287 288$METHOD_MAP{NT} = $METHOD_MAP{MSWin32}; 289$METHOD_MAP{nto} = $METHOD_MAP{qnx}; 290 291 292# Find the pwd command in the expected locations. We assume these 293# are safe. This prevents _backtick_pwd() consulting $ENV{PATH} 294# so everything works under taint mode. 295my $pwd_cmd; 296foreach my $try ('/bin/pwd', 297 '/usr/bin/pwd', 298 '/QOpenSys/bin/pwd', # OS/400 PASE. 299 ) { 300 301 if( -x $try ) { 302 $pwd_cmd = $try; 303 last; 304 } 305} 306my $found_pwd_cmd = defined($pwd_cmd); 307unless ($pwd_cmd) { 308 # Isn't this wrong? _backtick_pwd() will fail if somenone has 309 # pwd in their path but it is not /bin/pwd or /usr/bin/pwd? 310 # See [perl #16774]. --jhi 311 $pwd_cmd = 'pwd'; 312} 313 314# Lazy-load Carp 315sub _carp { require Carp; Carp::carp(@_) } 316sub _croak { require Carp; Carp::croak(@_) } 317 318# The 'natural and safe form' for UNIX (pwd may be setuid root) 319sub _backtick_pwd { 320 # Localize %ENV entries in a way that won't create new hash keys 321 my @localize = grep exists $ENV{$_}, qw(PATH IFS CDPATH ENV BASH_ENV); 322 local @ENV{@localize}; 323 324 my $cwd = `$pwd_cmd`; 325 # Belt-and-suspenders in case someone said "undef $/". 326 local $/ = "\n"; 327 # `pwd` may fail e.g. if the disk is full 328 chomp($cwd) if defined $cwd; 329 $cwd; 330} 331 332# Since some ports may predefine cwd internally (e.g., NT) 333# we take care not to override an existing definition for cwd(). 334 335unless ($METHOD_MAP{$^O}{cwd} or defined &cwd) { 336 # The pwd command is not available in some chroot(2)'ed environments 337 my $sep = $Config::Config{path_sep} || ':'; 338 my $os = $^O; # Protect $^O from tainting 339 340 341 # Try again to find a pwd, this time searching the whole PATH. 342 if (defined $ENV{PATH} and $os ne 'MSWin32') { # no pwd on Windows 343 my @candidates = split($sep, $ENV{PATH}); 344 while (!$found_pwd_cmd and @candidates) { 345 my $candidate = shift @candidates; 346 $found_pwd_cmd = 1 if -x "$candidate/pwd"; 347 } 348 } 349 350 # MacOS has some special magic to make `pwd` work. 351 if( $os eq 'MacOS' || $found_pwd_cmd ) 352 { 353 *cwd = \&_backtick_pwd; 354 } 355 else { 356 *cwd = \&getcwd; 357 } 358} 359 360if ($^O eq 'cygwin') { 361 # We need to make sure cwd() is called with no args, because it's 362 # got an arg-less prototype and will die if args are present. 363 local $^W = 0; 364 my $orig_cwd = \&cwd; 365 *cwd = sub { &$orig_cwd() } 366} 367 368 369# set a reasonable (and very safe) default for fastgetcwd, in case it 370# isn't redefined later (20001212 rspier) 371*fastgetcwd = \&cwd; 372 373# A non-XS version of getcwd() - also used to bootstrap the perl build 374# process, when miniperl is running and no XS loading happens. 375sub _perl_getcwd 376{ 377 abs_path('.'); 378} 379 380# By John Bazik 381# 382# Usage: $cwd = &fastcwd; 383# 384# This is a faster version of getcwd. It's also more dangerous because 385# you might chdir out of a directory that you can't chdir back into. 386 387sub fastcwd_ { 388 my($odev, $oino, $cdev, $cino, $tdev, $tino); 389 my(@path, $path); 390 local(*DIR); 391 392 my($orig_cdev, $orig_cino) = stat('.'); 393 ($cdev, $cino) = ($orig_cdev, $orig_cino); 394 for (;;) { 395 my $direntry; 396 ($odev, $oino) = ($cdev, $cino); 397 CORE::chdir('..') || return undef; 398 ($cdev, $cino) = stat('.'); 399 last if $odev == $cdev && $oino == $cino; 400 opendir(DIR, '.') || return undef; 401 for (;;) { 402 $direntry = readdir(DIR); 403 last unless defined $direntry; 404 next if $direntry eq '.'; 405 next if $direntry eq '..'; 406 407 ($tdev, $tino) = lstat($direntry); 408 last unless $tdev != $odev || $tino != $oino; 409 } 410 closedir(DIR); 411 return undef unless defined $direntry; # should never happen 412 unshift(@path, $direntry); 413 } 414 $path = '/' . join('/', @path); 415 if ($^O eq 'apollo') { $path = "/".$path; } 416 # At this point $path may be tainted (if tainting) and chdir would fail. 417 # Untaint it then check that we landed where we started. 418 $path =~ /^(.*)\z/s # untaint 419 && CORE::chdir($1) or return undef; 420 ($cdev, $cino) = stat('.'); 421 die "Unstable directory path, current directory changed unexpectedly" 422 if $cdev != $orig_cdev || $cino != $orig_cino; 423 $path; 424} 425if (not defined &fastcwd) { *fastcwd = \&fastcwd_ } 426 427 428# Keeps track of current working directory in PWD environment var 429# Usage: 430# use Cwd 'chdir'; 431# chdir $newdir; 432 433my $chdir_init = 0; 434 435sub chdir_init { 436 if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos' and $^O ne 'MSWin32') { 437 my($dd,$di) = stat('.'); 438 my($pd,$pi) = stat($ENV{'PWD'}); 439 if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) { 440 $ENV{'PWD'} = cwd(); 441 } 442 } 443 else { 444 my $wd = cwd(); 445 $wd = Win32::GetFullPathName($wd) if $^O eq 'MSWin32'; 446 $ENV{'PWD'} = $wd; 447 } 448 # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar) 449 if ($^O ne 'MSWin32' and $ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|s) { 450 my($pd,$pi) = stat($2); 451 my($dd,$di) = stat($1); 452 if (defined $pd and defined $dd and $di == $pi and $dd == $pd) { 453 $ENV{'PWD'}="$2$3"; 454 } 455 } 456 $chdir_init = 1; 457} 458 459sub chdir { 460 my $newdir = @_ ? shift : ''; # allow for no arg (chdir to HOME dir) 461 $newdir =~ s|///*|/|g unless $^O eq 'MSWin32'; 462 chdir_init() unless $chdir_init; 463 my $newpwd; 464 if ($^O eq 'MSWin32') { 465 # get the full path name *before* the chdir() 466 $newpwd = Win32::GetFullPathName($newdir); 467 } 468 469 return 0 unless CORE::chdir $newdir; 470 471 if ($^O eq 'VMS') { 472 return $ENV{'PWD'} = $ENV{'DEFAULT'} 473 } 474 elsif ($^O eq 'MacOS') { 475 return $ENV{'PWD'} = cwd(); 476 } 477 elsif ($^O eq 'MSWin32') { 478 $ENV{'PWD'} = $newpwd; 479 return 1; 480 } 481 482 if (ref $newdir eq 'GLOB') { # in case a file/dir handle is passed in 483 $ENV{'PWD'} = cwd(); 484 } elsif ($newdir =~ m#^/#s) { 485 $ENV{'PWD'} = $newdir; 486 } else { 487 my @curdir = split(m#/#,$ENV{'PWD'}); 488 @curdir = ('') unless @curdir; 489 my $component; 490 foreach $component (split(m#/#, $newdir)) { 491 next if $component eq '.'; 492 pop(@curdir),next if $component eq '..'; 493 push(@curdir,$component); 494 } 495 $ENV{'PWD'} = join('/',@curdir) || '/'; 496 } 497 1; 498} 499 500 501sub _perl_abs_path 502{ 503 my $start = @_ ? shift : '.'; 504 my($dotdots, $cwd, @pst, @cst, $dir, @tst); 505 506 unless (@cst = stat( $start )) 507 { 508 _carp("stat($start): $!"); 509 return ''; 510 } 511 512 unless (-d _) { 513 # Make sure we can be invoked on plain files, not just directories. 514 # NOTE that this routine assumes that '/' is the only directory separator. 515 516 my ($dir, $file) = $start =~ m{^(.*)/(.+)$} 517 or return cwd() . '/' . $start; 518 519 # Can't use "-l _" here, because the previous stat was a stat(), not an lstat(). 520 if (-l $start) { 521 my $link_target = readlink($start); 522 die "Can't resolve link $start: $!" unless defined $link_target; 523 524 require File::Spec; 525 $link_target = $dir . '/' . $link_target 526 unless File::Spec->file_name_is_absolute($link_target); 527 528 return abs_path($link_target); 529 } 530 531 return $dir ? abs_path($dir) . "/$file" : "/$file"; 532 } 533 534 $cwd = ''; 535 $dotdots = $start; 536 do 537 { 538 $dotdots .= '/..'; 539 @pst = @cst; 540 local *PARENT; 541 unless (opendir(PARENT, $dotdots)) 542 { 543 _carp("opendir($dotdots): $!"); 544 return ''; 545 } 546 unless (@cst = stat($dotdots)) 547 { 548 _carp("stat($dotdots): $!"); 549 closedir(PARENT); 550 return ''; 551 } 552 if ($pst[0] == $cst[0] && $pst[1] == $cst[1]) 553 { 554 $dir = undef; 555 } 556 else 557 { 558 do 559 { 560 unless (defined ($dir = readdir(PARENT))) 561 { 562 _carp("readdir($dotdots): $!"); 563 closedir(PARENT); 564 return ''; 565 } 566 $tst[0] = $pst[0]+1 unless (@tst = lstat("$dotdots/$dir")) 567 } 568 while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] || 569 $tst[1] != $pst[1]); 570 } 571 $cwd = (defined $dir ? "$dir" : "" ) . "/$cwd" ; 572 closedir(PARENT); 573 } while (defined $dir); 574 chop($cwd) unless $cwd eq '/'; # drop the trailing / 575 $cwd; 576} 577 578 579my $Curdir; 580sub fast_abs_path { 581 local $ENV{PWD} = $ENV{PWD} || ''; # Guard against clobberage 582 my $cwd = getcwd(); 583 require File::Spec; 584 my $path = @_ ? shift : ($Curdir ||= File::Spec->curdir); 585 586 # Detaint else we'll explode in taint mode. This is safe because 587 # we're not doing anything dangerous with it. 588 ($path) = $path =~ /(.*)/; 589 ($cwd) = $cwd =~ /(.*)/; 590 591 unless (-e $path) { 592 _croak("$path: No such file or directory"); 593 } 594 595 unless (-d _) { 596 # Make sure we can be invoked on plain files, not just directories. 597 598 my ($vol, $dir, $file) = File::Spec->splitpath($path); 599 return File::Spec->catfile($cwd, $path) unless length $dir; 600 601 if (-l $path) { 602 my $link_target = readlink($path); 603 die "Can't resolve link $path: $!" unless defined $link_target; 604 605 $link_target = File::Spec->catpath($vol, $dir, $link_target) 606 unless File::Spec->file_name_is_absolute($link_target); 607 608 return fast_abs_path($link_target); 609 } 610 611 return $dir eq File::Spec->rootdir 612 ? File::Spec->catpath($vol, $dir, $file) 613 : fast_abs_path(File::Spec->catpath($vol, $dir, '')) . '/' . $file; 614 } 615 616 if (!CORE::chdir($path)) { 617 _croak("Cannot chdir to $path: $!"); 618 } 619 my $realpath = getcwd(); 620 if (! ((-d $cwd) && (CORE::chdir($cwd)))) { 621 _croak("Cannot chdir back to $cwd: $!"); 622 } 623 $realpath; 624} 625 626# added function alias to follow principle of least surprise 627# based on previous aliasing. --tchrist 27-Jan-00 628*fast_realpath = \&fast_abs_path; 629 630 631# --- PORTING SECTION --- 632 633# VMS: $ENV{'DEFAULT'} points to default directory at all times 634# 06-Mar-1996 Charles Bailey bailey@newman.upenn.edu 635# Note: Use of Cwd::chdir() causes the logical name PWD to be defined 636# in the process logical name table as the default device and directory 637# seen by Perl. This may not be the same as the default device 638# and directory seen by DCL after Perl exits, since the effects 639# the CRTL chdir() function persist only until Perl exits. 640 641sub _vms_cwd { 642 return $ENV{'DEFAULT'}; 643} 644 645sub _vms_abs_path { 646 return $ENV{'DEFAULT'} unless @_; 647 648 # may need to turn foo.dir into [.foo] 649 my $path = VMS::Filespec::pathify($_[0]); 650 $path = $_[0] unless defined $path; 651 652 return VMS::Filespec::rmsexpand($path); 653} 654 655sub _os2_cwd { 656 $ENV{'PWD'} = `cmd /c cd`; 657 chomp $ENV{'PWD'}; 658 $ENV{'PWD'} =~ s:\\:/:g ; 659 return $ENV{'PWD'}; 660} 661 662sub _win32_cwd { 663 $ENV{'PWD'} = Win32::GetCwd(); 664 $ENV{'PWD'} =~ s:\\:/:g ; 665 return $ENV{'PWD'}; 666} 667 668*_NT_cwd = defined &Win32::GetCwd ? \&_win32_cwd : \&_os2_cwd; 669 670sub _dos_cwd { 671 if (!defined &Dos::GetCwd) { 672 $ENV{'PWD'} = `command /c cd`; 673 chomp $ENV{'PWD'}; 674 $ENV{'PWD'} =~ s:\\:/:g ; 675 } else { 676 $ENV{'PWD'} = Dos::GetCwd(); 677 } 678 return $ENV{'PWD'}; 679} 680 681sub _qnx_cwd { 682 local $ENV{PATH} = ''; 683 local $ENV{CDPATH} = ''; 684 local $ENV{ENV} = ''; 685 $ENV{'PWD'} = `/usr/bin/fullpath -t`; 686 chomp $ENV{'PWD'}; 687 return $ENV{'PWD'}; 688} 689 690sub _qnx_abs_path { 691 local $ENV{PATH} = ''; 692 local $ENV{CDPATH} = ''; 693 local $ENV{ENV} = ''; 694 my $path = @_ ? shift : '.'; 695 local *REALPATH; 696 697 defined( open(REALPATH, '-|') || exec '/usr/bin/fullpath', '-t', $path ) or 698 die "Can't open /usr/bin/fullpath: $!"; 699 my $realpath = <REALPATH>; 700 close REALPATH; 701 chomp $realpath; 702 return $realpath; 703} 704 705sub _epoc_cwd { 706 $ENV{'PWD'} = EPOC::getcwd(); 707 return $ENV{'PWD'}; 708} 709 710 711# Now that all the base-level functions are set up, alias the 712# user-level functions to the right places 713 714if (exists $METHOD_MAP{$^O}) { 715 my $map = $METHOD_MAP{$^O}; 716 foreach my $name (keys %$map) { 717 local $^W = 0; # assignments trigger 'subroutine redefined' warning 718 no strict 'refs'; 719 *{$name} = \&{$map->{$name}}; 720 } 721} 722 723# In case the XS version doesn't load. 724*abs_path = \&_perl_abs_path unless defined &abs_path; 725*getcwd = \&_perl_getcwd unless defined &getcwd; 726 727# added function alias for those of us more 728# used to the libc function. --tchrist 27-Jan-00 729*realpath = \&abs_path; 730 7311; 732