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1 | package Cwd; |
2 | use 5.006; | |
3 | ||
4 | =head1 NAME | |
5 | ||
6 | Cwd - get pathname of current working directory | |
7 | ||
8 | =head1 SYNOPSIS | |
9 | ||
10 | use Cwd; | |
11 | my $dir = getcwd; | |
12 | ||
13 | use Cwd 'abs_path'; | |
14 | my $abs_path = abs_path($file); | |
15 | ||
16 | =head1 DESCRIPTION | |
17 | ||
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. | |
21 | ||
22 | By default, it exports the functions cwd(), getcwd(), fastcwd(), and | |
23 | fastgetcwd() into the caller's namespace. | |
24 | ||
25 | ||
26 | =head2 getcwd and friends | |
27 | ||
28 | Each of these functions are called without arguments and return the | |
29 | absolute path of the current working directory. | |
30 | ||
31 | =over 4 | |
32 | ||
33 | =item getcwd | |
34 | ||
35 | my $cwd = getcwd(); | |
36 | ||
37 | Returns the current working directory. | |
38 | ||
39 | Re-implements the getcwd(3) (or getwd(3)) functions in Perl. | |
40 | ||
41 | Taint-safe. | |
42 | ||
43 | =item cwd | |
44 | ||
45 | my $cwd = cwd(); | |
46 | ||
47 | The cwd() is the most natural form for the current architecture. For | |
48 | most systems it is identical to `pwd` (but without the trailing line | |
49 | terminator). | |
50 | ||
51 | Taint-safe. | |
52 | ||
53 | =item fastcwd | |
54 | ||
55 | my $cwd = fastcwd(); | |
56 | ||
57 | A more dangerous version of getcwd(), but potentially faster. | |
58 | ||
59 | It might conceivably chdir() you out of a directory that it can't | |
60 | chdir() you back into. If fastcwd encounters a problem it will return | |
61 | undef but will probably leave you in a different directory. For a | |
62 | measure of extra security, if everything appears to have worked, the | |
63 | fastcwd() function will check that it leaves you in the same directory | |
64 | that it started in. If it has changed it will C<die> with the message | |
65 | "Unstable directory path, current directory changed | |
66 | unexpectedly". That should never happen. | |
67 | ||
68 | =item fastgetcwd | |
69 | ||
70 | my $cwd = fastgetcwd(); | |
71 | ||
72 | The fastgetcwd() function is provided as a synonym for cwd(). | |
73 | ||
74 | =back | |
75 | ||
76 | ||
77 | =head2 abs_path and friends | |
78 | ||
79 | These functions are exported only on request. They each take a single | |
80 | argument and return the absolute pathname for it. | |
81 | ||
82 | =over 4 | |
83 | ||
84 | =item abs_path | |
85 | ||
86 | my $abs_path = abs_path($file); | |
87 | ||
88 | Uses the same algorithm as getcwd(). Symbolic links and relative-path | |
89 | components ("." and "..") are resolved to return the canonical | |
90 | pathname, just like realpath(3). | |
91 | ||
92 | Taint-safe. | |
93 | ||
94 | =item realpath | |
95 | ||
96 | my $abs_path = realpath($file); | |
97 | ||
98 | A synonym for abs_path(). | |
99 | ||
100 | Taint-safe. | |
101 | ||
102 | =item fast_abs_path | |
103 | ||
104 | my $abs_path = fast_abs_path($file); | |
105 | ||
106 | A more dangerous, but potentially faster version of abs_path. | |
107 | ||
108 | This function is B<Not> taint-safe : you can't use it in programs | |
109 | that work under taint mode. | |
110 | ||
111 | =back | |
112 | ||
113 | =head2 $ENV{PWD} | |
114 | ||
115 | If you ask to override your chdir() built-in function, | |
116 | ||
117 | use Cwd qw(chdir); | |
118 | ||
119 | then your PWD environment variable will be kept up to date. Note that | |
120 | it will only be kept up to date if all packages which use chdir import | |
121 | it from Cwd. | |
122 | ||
123 | ||
124 | =head1 NOTES | |
125 | ||
126 | =over 4 | |
127 | ||
128 | =item * | |
129 | ||
130 | Since the path seperators are different on some operating systems ('/' | |
131 | on Unix, ':' on MacPerl, etc...) we recommend you use the File::Spec | |
132 | modules wherever portability is a concern. | |
133 | ||
134 | =item * | |
135 | ||
136 | Actually, on Mac OS, the C<getcwd()>, C<fastgetcwd()> and C<fastcwd()> | |
137 | functions are all aliases for the C<cwd()> function, which, on Mac OS, | |
138 | calls `pwd`. Likewise, the C<abs_path()> function is an alias for | |
139 | C<fast_abs_path()>. | |
140 | ||
141 | =back | |
142 | ||
143 | =head1 SEE ALSO | |
144 | ||
145 | L<File::chdir> | |
146 | ||
147 | =cut | |
148 | ||
149 | use strict; | |
150 | ||
151 | use Carp; | |
152 | ||
153 | our $VERSION = '2.06'; | |
154 | ||
155 | use base qw/ Exporter /; | |
156 | our @EXPORT = qw(cwd getcwd fastcwd fastgetcwd); | |
157 | our @EXPORT_OK = qw(chdir abs_path fast_abs_path realpath fast_realpath); | |
158 | ||
159 | # sys_cwd may keep the builtin command | |
160 | ||
161 | # All the functionality of this module may provided by builtins, | |
162 | # there is no sense to process the rest of the file. | |
163 | # The best choice may be to have this in BEGIN, but how to return from BEGIN? | |
164 | ||
165 | if ($^O eq 'os2' && defined &sys_cwd && defined &sys_abspath) { | |
166 | local $^W = 0; | |
167 | *cwd = \&sys_cwd; | |
168 | *getcwd = \&cwd; | |
169 | *fastgetcwd = \&cwd; | |
170 | *fastcwd = \&cwd; | |
171 | *abs_path = \&sys_abspath; | |
172 | *fast_abs_path = \&abs_path; | |
173 | *realpath = \&abs_path; | |
174 | *fast_realpath = \&abs_path; | |
175 | return 1; | |
176 | } | |
177 | ||
178 | eval { | |
179 | require XSLoader; | |
180 | undef *Cwd::fastcwd; # avoid redefinition warning | |
181 | XSLoader::load('Cwd'); | |
182 | }; | |
183 | ||
184 | ||
185 | # Find the pwd command in the expected locations. We assume these | |
186 | # are safe. This prevents _backtick_pwd() consulting $ENV{PATH} | |
187 | # so everything works under taint mode. | |
188 | my $pwd_cmd; | |
189 | foreach my $try (qw(/bin/pwd /usr/bin/pwd)) { | |
190 | if( -x $try ) { | |
191 | $pwd_cmd = $try; | |
192 | last; | |
193 | } | |
194 | } | |
195 | $pwd_cmd ||= 'pwd'; | |
196 | ||
197 | # The 'natural and safe form' for UNIX (pwd may be setuid root) | |
198 | sub _backtick_pwd { | |
199 | local @ENV{qw(PATH IFS CDPATH ENV BASH_ENV)}; | |
200 | my $cwd = `$pwd_cmd`; | |
201 | # Belt-and-suspenders in case someone said "undef $/". | |
202 | local $/ = "\n"; | |
203 | # `pwd` may fail e.g. if the disk is full | |
204 | chomp($cwd) if defined $cwd; | |
205 | $cwd; | |
206 | } | |
207 | ||
208 | # Since some ports may predefine cwd internally (e.g., NT) | |
209 | # we take care not to override an existing definition for cwd(). | |
210 | ||
211 | unless(defined &cwd) { | |
212 | # The pwd command is not available in some chroot(2)'ed environments | |
213 | if( $^O eq 'MacOS' || (defined $ENV{PATH} && | |
214 | grep { -x "$_/pwd" } split(':', $ENV{PATH})) ) | |
215 | { | |
216 | *cwd = \&_backtick_pwd; | |
217 | } | |
218 | else { | |
219 | *cwd = \&getcwd; | |
220 | } | |
221 | } | |
222 | ||
223 | # set a reasonable (and very safe) default for fastgetcwd, in case it | |
224 | # isn't redefined later (20001212 rspier) | |
225 | *fastgetcwd = \&cwd; | |
226 | ||
227 | # By Brandon S. Allbery | |
228 | # | |
229 | # Usage: $cwd = getcwd(); | |
230 | ||
231 | sub getcwd | |
232 | { | |
233 | abs_path('.'); | |
234 | } | |
235 | ||
236 | ||
237 | # By John Bazik | |
238 | # | |
239 | # Usage: $cwd = &fastcwd; | |
240 | # | |
241 | # This is a faster version of getcwd. It's also more dangerous because | |
242 | # you might chdir out of a directory that you can't chdir back into. | |
243 | ||
244 | sub fastcwd { | |
245 | my($odev, $oino, $cdev, $cino, $tdev, $tino); | |
246 | my(@path, $path); | |
247 | local(*DIR); | |
248 | ||
249 | my($orig_cdev, $orig_cino) = stat('.'); | |
250 | ($cdev, $cino) = ($orig_cdev, $orig_cino); | |
251 | for (;;) { | |
252 | my $direntry; | |
253 | ($odev, $oino) = ($cdev, $cino); | |
254 | CORE::chdir('..') || return undef; | |
255 | ($cdev, $cino) = stat('.'); | |
256 | last if $odev == $cdev && $oino == $cino; | |
257 | opendir(DIR, '.') || return undef; | |
258 | for (;;) { | |
259 | $direntry = readdir(DIR); | |
260 | last unless defined $direntry; | |
261 | next if $direntry eq '.'; | |
262 | next if $direntry eq '..'; | |
263 | ||
264 | ($tdev, $tino) = lstat($direntry); | |
265 | last unless $tdev != $odev || $tino != $oino; | |
266 | } | |
267 | closedir(DIR); | |
268 | return undef unless defined $direntry; # should never happen | |
269 | unshift(@path, $direntry); | |
270 | } | |
271 | $path = '/' . join('/', @path); | |
272 | if ($^O eq 'apollo') { $path = "/".$path; } | |
273 | # At this point $path may be tainted (if tainting) and chdir would fail. | |
274 | # Untaint it then check that we landed where we started. | |
275 | $path =~ /^(.*)\z/s # untaint | |
276 | && CORE::chdir($1) or return undef; | |
277 | ($cdev, $cino) = stat('.'); | |
278 | die "Unstable directory path, current directory changed unexpectedly" | |
279 | if $cdev != $orig_cdev || $cino != $orig_cino; | |
280 | $path; | |
281 | } | |
282 | ||
283 | ||
284 | # Keeps track of current working directory in PWD environment var | |
285 | # Usage: | |
286 | # use Cwd 'chdir'; | |
287 | # chdir $newdir; | |
288 | ||
289 | my $chdir_init = 0; | |
290 | ||
291 | sub chdir_init { | |
292 | if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'dos' and $^O ne 'MSWin32') { | |
293 | my($dd,$di) = stat('.'); | |
294 | my($pd,$pi) = stat($ENV{'PWD'}); | |
295 | if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) { | |
296 | $ENV{'PWD'} = cwd(); | |
297 | } | |
298 | } | |
299 | else { | |
300 | my $wd = cwd(); | |
301 | $wd = Win32::GetFullPathName($wd) if $^O eq 'MSWin32'; | |
302 | $ENV{'PWD'} = $wd; | |
303 | } | |
304 | # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar) | |
305 | if ($^O ne 'MSWin32' and $ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|s) { | |
306 | my($pd,$pi) = stat($2); | |
307 | my($dd,$di) = stat($1); | |
308 | if (defined $pd and defined $dd and $di == $pi and $dd == $pd) { | |
309 | $ENV{'PWD'}="$2$3"; | |
310 | } | |
311 | } | |
312 | $chdir_init = 1; | |
313 | } | |
314 | ||
315 | sub chdir { | |
316 | my $newdir = @_ ? shift : ''; # allow for no arg (chdir to HOME dir) | |
317 | $newdir =~ s|///*|/|g unless $^O eq 'MSWin32'; | |
318 | chdir_init() unless $chdir_init; | |
319 | my $newpwd; | |
320 | if ($^O eq 'MSWin32') { | |
321 | # get the full path name *before* the chdir() | |
322 | $newpwd = Win32::GetFullPathName($newdir); | |
323 | } | |
324 | ||
325 | return 0 unless CORE::chdir $newdir; | |
326 | ||
327 | if ($^O eq 'VMS') { | |
328 | return $ENV{'PWD'} = $ENV{'DEFAULT'} | |
329 | } | |
330 | elsif ($^O eq 'MacOS') { | |
331 | return $ENV{'PWD'} = cwd(); | |
332 | } | |
333 | elsif ($^O eq 'MSWin32') { | |
334 | $ENV{'PWD'} = $newpwd; | |
335 | return 1; | |
336 | } | |
337 | ||
338 | if ($newdir =~ m#^/#s) { | |
339 | $ENV{'PWD'} = $newdir; | |
340 | } else { | |
341 | my @curdir = split(m#/#,$ENV{'PWD'}); | |
342 | @curdir = ('') unless @curdir; | |
343 | my $component; | |
344 | foreach $component (split(m#/#, $newdir)) { | |
345 | next if $component eq '.'; | |
346 | pop(@curdir),next if $component eq '..'; | |
347 | push(@curdir,$component); | |
348 | } | |
349 | $ENV{'PWD'} = join('/',@curdir) || '/'; | |
350 | } | |
351 | 1; | |
352 | } | |
353 | ||
354 | ||
355 | # In case the XS version doesn't load. | |
356 | *abs_path = \&_perl_abs_path unless defined &abs_path; | |
357 | sub _perl_abs_path | |
358 | { | |
359 | my $start = @_ ? shift : '.'; | |
360 | my($dotdots, $cwd, @pst, @cst, $dir, @tst); | |
361 | ||
362 | unless (@cst = stat( $start )) | |
363 | { | |
364 | carp "stat($start): $!"; | |
365 | return ''; | |
366 | } | |
367 | $cwd = ''; | |
368 | $dotdots = $start; | |
369 | do | |
370 | { | |
371 | $dotdots .= '/..'; | |
372 | @pst = @cst; | |
373 | unless (opendir(PARENT, $dotdots)) | |
374 | { | |
375 | carp "opendir($dotdots): $!"; | |
376 | return ''; | |
377 | } | |
378 | unless (@cst = stat($dotdots)) | |
379 | { | |
380 | carp "stat($dotdots): $!"; | |
381 | closedir(PARENT); | |
382 | return ''; | |
383 | } | |
384 | if ($pst[0] == $cst[0] && $pst[1] == $cst[1]) | |
385 | { | |
386 | $dir = undef; | |
387 | } | |
388 | else | |
389 | { | |
390 | do | |
391 | { | |
392 | unless (defined ($dir = readdir(PARENT))) | |
393 | { | |
394 | carp "readdir($dotdots): $!"; | |
395 | closedir(PARENT); | |
396 | return ''; | |
397 | } | |
398 | $tst[0] = $pst[0]+1 unless (@tst = lstat("$dotdots/$dir")) | |
399 | } | |
400 | while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] || | |
401 | $tst[1] != $pst[1]); | |
402 | } | |
403 | $cwd = (defined $dir ? "$dir" : "" ) . "/$cwd" ; | |
404 | closedir(PARENT); | |
405 | } while (defined $dir); | |
406 | chop($cwd) unless $cwd eq '/'; # drop the trailing / | |
407 | $cwd; | |
408 | } | |
409 | ||
410 | ||
411 | # added function alias for those of us more | |
412 | # used to the libc function. --tchrist 27-Jan-00 | |
413 | *realpath = \&abs_path; | |
414 | ||
415 | sub fast_abs_path { | |
416 | my $cwd = getcwd(); | |
417 | require File::Spec; | |
418 | my $path = @_ ? shift : File::Spec->curdir; | |
419 | CORE::chdir($path) || croak "Cannot chdir to $path: $!"; | |
420 | my $realpath = getcwd(); | |
421 | -d $cwd && CORE::chdir($cwd) || | |
422 | croak "Cannot chdir back to $cwd: $!"; | |
423 | $realpath; | |
424 | } | |
425 | ||
426 | # added function alias to follow principle of least surprise | |
427 | # based on previous aliasing. --tchrist 27-Jan-00 | |
428 | *fast_realpath = \&fast_abs_path; | |
429 | ||
430 | ||
431 | # --- PORTING SECTION --- | |
432 | ||
433 | # VMS: $ENV{'DEFAULT'} points to default directory at all times | |
434 | # 06-Mar-1996 Charles Bailey bailey@newman.upenn.edu | |
435 | # Note: Use of Cwd::chdir() causes the logical name PWD to be defined | |
436 | # in the process logical name table as the default device and directory | |
437 | # seen by Perl. This may not be the same as the default device | |
438 | # and directory seen by DCL after Perl exits, since the effects | |
439 | # the CRTL chdir() function persist only until Perl exits. | |
440 | ||
441 | sub _vms_cwd { | |
442 | return $ENV{'DEFAULT'}; | |
443 | } | |
444 | ||
445 | sub _vms_abs_path { | |
446 | return $ENV{'DEFAULT'} unless @_; | |
447 | my $path = VMS::Filespec::pathify($_[0]); | |
448 | croak("Invalid path name $_[0]") unless defined $path; | |
449 | return VMS::Filespec::rmsexpand($path); | |
450 | } | |
451 | ||
452 | sub _os2_cwd { | |
453 | $ENV{'PWD'} = `cmd /c cd`; | |
454 | chop $ENV{'PWD'}; | |
455 | $ENV{'PWD'} =~ s:\\:/:g ; | |
456 | return $ENV{'PWD'}; | |
457 | } | |
458 | ||
459 | sub _win32_cwd { | |
460 | $ENV{'PWD'} = Win32::GetCwd(); | |
461 | $ENV{'PWD'} =~ s:\\:/:g ; | |
462 | return $ENV{'PWD'}; | |
463 | } | |
464 | ||
465 | *_NT_cwd = \&_win32_cwd if (!defined &_NT_cwd && | |
466 | defined &Win32::GetCwd); | |
467 | ||
468 | *_NT_cwd = \&_os2_cwd unless defined &_NT_cwd; | |
469 | ||
470 | sub _dos_cwd { | |
471 | if (!defined &Dos::GetCwd) { | |
472 | $ENV{'PWD'} = `command /c cd`; | |
473 | chop $ENV{'PWD'}; | |
474 | $ENV{'PWD'} =~ s:\\:/:g ; | |
475 | } else { | |
476 | $ENV{'PWD'} = Dos::GetCwd(); | |
477 | } | |
478 | return $ENV{'PWD'}; | |
479 | } | |
480 | ||
481 | sub _qnx_cwd { | |
482 | local $ENV{PATH} = ''; | |
483 | local $ENV{CDPATH} = ''; | |
484 | local $ENV{ENV} = ''; | |
485 | $ENV{'PWD'} = `/usr/bin/fullpath -t`; | |
486 | chop $ENV{'PWD'}; | |
487 | return $ENV{'PWD'}; | |
488 | } | |
489 | ||
490 | sub _qnx_abs_path { | |
491 | local $ENV{PATH} = ''; | |
492 | local $ENV{CDPATH} = ''; | |
493 | local $ENV{ENV} = ''; | |
494 | my $path = @_ ? shift : '.'; | |
495 | my $realpath=`/usr/bin/fullpath -t $path`; | |
496 | chop $realpath; | |
497 | return $realpath; | |
498 | } | |
499 | ||
500 | sub _epoc_cwd { | |
501 | $ENV{'PWD'} = EPOC::getcwd(); | |
502 | return $ENV{'PWD'}; | |
503 | } | |
504 | ||
505 | { | |
506 | no warnings; # assignments trigger 'subroutine redefined' warning | |
507 | ||
508 | if ($^O eq 'VMS') { | |
509 | *cwd = \&_vms_cwd; | |
510 | *getcwd = \&_vms_cwd; | |
511 | *fastcwd = \&_vms_cwd; | |
512 | *fastgetcwd = \&_vms_cwd; | |
513 | *abs_path = \&_vms_abs_path; | |
514 | *fast_abs_path = \&_vms_abs_path; | |
515 | } | |
516 | elsif ($^O eq 'NT' or $^O eq 'MSWin32') { | |
517 | # We assume that &_NT_cwd is defined as an XSUB or in the core. | |
518 | *cwd = \&_NT_cwd; | |
519 | *getcwd = \&_NT_cwd; | |
520 | *fastcwd = \&_NT_cwd; | |
521 | *fastgetcwd = \&_NT_cwd; | |
522 | *abs_path = \&fast_abs_path; | |
523 | *realpath = \&fast_abs_path; | |
524 | } | |
525 | elsif ($^O eq 'os2') { | |
526 | # sys_cwd may keep the builtin command | |
527 | *cwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd; | |
528 | *getcwd = \&cwd; | |
529 | *fastgetcwd = \&cwd; | |
530 | *fastcwd = \&cwd; | |
531 | *abs_path = \&fast_abs_path; | |
532 | } | |
533 | elsif ($^O eq 'dos') { | |
534 | *cwd = \&_dos_cwd; | |
535 | *getcwd = \&_dos_cwd; | |
536 | *fastgetcwd = \&_dos_cwd; | |
537 | *fastcwd = \&_dos_cwd; | |
538 | *abs_path = \&fast_abs_path; | |
539 | } | |
540 | elsif ($^O =~ m/^(?:qnx|nto)$/ ) { | |
541 | *cwd = \&_qnx_cwd; | |
542 | *getcwd = \&_qnx_cwd; | |
543 | *fastgetcwd = \&_qnx_cwd; | |
544 | *fastcwd = \&_qnx_cwd; | |
545 | *abs_path = \&_qnx_abs_path; | |
546 | *fast_abs_path = \&_qnx_abs_path; | |
547 | } | |
548 | elsif ($^O eq 'cygwin') { | |
549 | *getcwd = \&cwd; | |
550 | *fastgetcwd = \&cwd; | |
551 | *fastcwd = \&cwd; | |
552 | *abs_path = \&fast_abs_path; | |
553 | } | |
554 | elsif ($^O eq 'epoc') { | |
555 | *cwd = \&_epoc_cwd; | |
556 | *getcwd = \&_epoc_cwd; | |
557 | *fastgetcwd = \&_epoc_cwd; | |
558 | *fastcwd = \&_epoc_cwd; | |
559 | *abs_path = \&fast_abs_path; | |
560 | } | |
561 | elsif ($^O eq 'MacOS') { | |
562 | *getcwd = \&cwd; | |
563 | *fastgetcwd = \&cwd; | |
564 | *fastcwd = \&cwd; | |
565 | *abs_path = \&fast_abs_path; | |
566 | } | |
567 | } | |
568 | ||
569 | ||
570 | 1; |