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1 | package Cwd; |
2 | require 5.000; |
3 | require Exporter; |
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4 | use Carp; |
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5 | |
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6 | =head1 NAME |
7 | |
8 | getcwd - get pathname of current working directory |
9 | |
10 | =head1 SYNOPSIS |
11 | |
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12 | use Cwd; |
13 | $dir = cwd; |
14 | |
15 | use Cwd; |
16 | $dir = getcwd; |
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17 | |
18 | use Cwd; |
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19 | $dir = fastgetcwd; |
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20 | |
21 | use Cwd 'chdir'; |
22 | chdir "/tmp"; |
23 | print $ENV{'PWD'}; |
24 | |
25 | =head1 DESCRIPTION |
26 | |
27 | The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions |
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28 | in Perl. |
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29 | |
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30 | The fastcwd() function looks the same as getcwd(), but runs faster. |
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31 | It's also more dangerous because you might conceivably chdir() out of a |
32 | directory that you can't chdir() back into. |
33 | |
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34 | The cwd() function looks the same as getcwd and fastgetcwd but is |
35 | implemented using the most natural and safe form for the current |
36 | architecture. For most systems it is identical to `pwd` (but without |
37 | the trailing line terminator). It is recommended that cwd (or another |
38 | *cwd() function) is used in I<all> code to ensure portability. |
39 | |
40 | If you ask to override your chdir() built-in function, then your PWD |
41 | environment variable will be kept up to date. (See |
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42 | L<perlsub/Overriding Builtin Functions>.) Note that it will only be |
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43 | kept up to date if all packages which use chdir import it from Cwd. |
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44 | |
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45 | =cut |
46 | |
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47 | @ISA = qw(Exporter); |
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48 | @EXPORT = qw(cwd getcwd fastcwd fastgetcwd); |
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49 | @EXPORT_OK = qw(chdir abs_path fast_abspath); |
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50 | |
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51 | # use strict; |
52 | |
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53 | # The 'natural and safe form' for UNIX (pwd may be setuid root) |
54 | sub _backtick_pwd { |
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55 | my $cwd; |
56 | chop($cwd = `pwd`); |
57 | $cwd; |
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58 | } |
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59 | |
60 | # Since some ports may predefine cwd internally (e.g., NT) |
61 | # we take care not to override an existing definition for cwd(). |
62 | |
63 | *cwd = \&_backtick_pwd unless defined &cwd; |
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64 | |
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65 | |
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66 | # By Brandon S. Allbery |
67 | # |
68 | # Usage: $cwd = getcwd(); |
69 | |
70 | sub getcwd |
71 | { |
72 | my($dotdots, $cwd, @pst, @cst, $dir, @tst); |
73 | |
74 | unless (@cst = stat('.')) |
75 | { |
76 | warn "stat(.): $!"; |
77 | return ''; |
78 | } |
79 | $cwd = ''; |
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80 | $dotdots = ''; |
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81 | do |
82 | { |
83 | $dotdots .= '/' if $dotdots; |
84 | $dotdots .= '..'; |
85 | @pst = @cst; |
86 | unless (opendir(PARENT, $dotdots)) |
87 | { |
88 | warn "opendir($dotdots): $!"; |
89 | return ''; |
90 | } |
91 | unless (@cst = stat($dotdots)) |
92 | { |
93 | warn "stat($dotdots): $!"; |
94 | closedir(PARENT); |
95 | return ''; |
96 | } |
97 | if ($pst[0] == $cst[0] && $pst[1] == $cst[1]) |
98 | { |
99 | $dir = ''; |
100 | } |
101 | else |
102 | { |
103 | do |
104 | { |
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105 | unless (defined ($dir = readdir(PARENT))) |
106 | { |
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107 | warn "readdir($dotdots): $!"; |
108 | closedir(PARENT); |
109 | return ''; |
110 | } |
111 | unless (@tst = lstat("$dotdots/$dir")) |
112 | { |
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113 | # warn "lstat($dotdots/$dir): $!"; |
37120919 |
114 | # Just because you can't lstat this directory |
115 | # doesn't mean you'll never find the right one. |
116 | # closedir(PARENT); |
117 | # return ''; |
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118 | } |
119 | } |
120 | while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] || |
121 | $tst[1] != $pst[1]); |
122 | } |
123 | $cwd = "$dir/$cwd"; |
124 | closedir(PARENT); |
125 | } while ($dir); |
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126 | chop($cwd) unless $cwd eq '/'; # drop the trailing / |
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127 | $cwd; |
128 | } |
129 | |
130 | |
131 | |
132 | # By John Bazik |
133 | # |
134 | # Usage: $cwd = &fastcwd; |
135 | # |
136 | # This is a faster version of getcwd. It's also more dangerous because |
137 | # you might chdir out of a directory that you can't chdir back into. |
138 | |
139 | sub fastcwd { |
140 | my($odev, $oino, $cdev, $cino, $tdev, $tino); |
141 | my(@path, $path); |
142 | local(*DIR); |
143 | |
144 | ($cdev, $cino) = stat('.'); |
145 | for (;;) { |
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146 | my $direntry; |
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147 | ($odev, $oino) = ($cdev, $cino); |
148 | chdir('..'); |
149 | ($cdev, $cino) = stat('.'); |
150 | last if $odev == $cdev && $oino == $cino; |
151 | opendir(DIR, '.'); |
152 | for (;;) { |
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153 | $direntry = readdir(DIR); |
154 | next if $direntry eq '.'; |
155 | next if $direntry eq '..'; |
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156 | |
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157 | last unless defined $direntry; |
158 | ($tdev, $tino) = lstat($direntry); |
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159 | last unless $tdev != $odev || $tino != $oino; |
160 | } |
161 | closedir(DIR); |
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162 | unshift(@path, $direntry); |
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163 | } |
164 | chdir($path = '/' . join('/', @path)); |
165 | $path; |
166 | } |
167 | |
168 | |
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169 | # Keeps track of current working directory in PWD environment var |
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170 | # Usage: |
171 | # use Cwd 'chdir'; |
172 | # chdir $newdir; |
173 | |
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174 | my $chdir_init = 0; |
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175 | |
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176 | sub chdir_init { |
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177 | if ($ENV{'PWD'} and $^O ne 'os2' and $^O ne 'msdos') { |
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178 | my($dd,$di) = stat('.'); |
179 | my($pd,$pi) = stat($ENV{'PWD'}); |
180 | if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) { |
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181 | $ENV{'PWD'} = cwd(); |
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182 | } |
183 | } |
184 | else { |
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185 | $ENV{'PWD'} = cwd(); |
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186 | } |
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187 | # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar) |
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188 | if ($ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|) { |
189 | my($pd,$pi) = stat($2); |
190 | my($dd,$di) = stat($1); |
191 | if (defined $pd and defined $dd and $di == $pi and $dd == $pd) { |
192 | $ENV{'PWD'}="$2$3"; |
193 | } |
194 | } |
195 | $chdir_init = 1; |
196 | } |
197 | |
198 | sub chdir { |
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199 | my $newdir = shift || ''; # allow for no arg (chdir to HOME dir) |
200 | $newdir =~ s|///*|/|g; |
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201 | chdir_init() unless $chdir_init; |
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202 | return 0 unless CORE::chdir $newdir; |
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203 | if ($^O eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} } |
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204 | |
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205 | if ($newdir =~ m#^/#) { |
206 | $ENV{'PWD'} = $newdir; |
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207 | } else { |
208 | my @curdir = split(m#/#,$ENV{'PWD'}); |
209 | @curdir = ('') unless @curdir; |
210 | my $component; |
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211 | foreach $component (split(m#/#, $newdir)) { |
212 | next if $component eq '.'; |
213 | pop(@curdir),next if $component eq '..'; |
214 | push(@curdir,$component); |
215 | } |
216 | $ENV{'PWD'} = join('/',@curdir) || '/'; |
217 | } |
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218 | 1; |
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219 | } |
220 | |
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221 | # Taken from Cwd.pm It is really getcwd with an optional |
222 | # parameter instead of '.' |
223 | # |
224 | |
225 | sub abs_path |
226 | { |
227 | my $start = shift || '.'; |
228 | my($dotdots, $cwd, @pst, @cst, $dir, @tst); |
229 | |
230 | unless (@cst = stat( $start )) |
231 | { |
232 | carp "stat($start): $!"; |
233 | return ''; |
234 | } |
235 | $cwd = ''; |
236 | $dotdots = $start; |
237 | do |
238 | { |
239 | $dotdots .= '/..'; |
240 | @pst = @cst; |
241 | unless (opendir(PARENT, $dotdots)) |
242 | { |
243 | carp "opendir($dotdots): $!"; |
244 | return ''; |
245 | } |
246 | unless (@cst = stat($dotdots)) |
247 | { |
248 | carp "stat($dotdots): $!"; |
249 | closedir(PARENT); |
250 | return ''; |
251 | } |
252 | if ($pst[0] == $cst[0] && $pst[1] == $cst[1]) |
253 | { |
254 | $dir = ''; |
255 | } |
256 | else |
257 | { |
258 | do |
259 | { |
260 | unless (defined ($dir = readdir(PARENT))) |
261 | { |
262 | carp "readdir($dotdots): $!"; |
263 | closedir(PARENT); |
264 | return ''; |
265 | } |
266 | $tst[0] = $pst[0]+1 unless (@tst = lstat("$dotdots/$dir")) |
267 | } |
268 | while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] || |
269 | $tst[1] != $pst[1]); |
270 | } |
271 | $cwd = "$dir/$cwd"; |
272 | closedir(PARENT); |
273 | } while ($dir); |
274 | chop($cwd); # drop the trailing / |
275 | $cwd; |
276 | } |
277 | |
278 | sub fast_abspath |
279 | { |
280 | my $cwd = getcwd(); |
281 | my $path = shift || '.'; |
282 | chdir($path) || croak "Cannot chdir to $path:$!"; |
283 | my $realpath = getcwd(); |
284 | chdir($cwd) || croak "Cannot chdir back to $cwd:$!"; |
285 | $realpath; |
286 | } |
287 | |
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288 | |
289 | # --- PORTING SECTION --- |
290 | |
291 | # VMS: $ENV{'DEFAULT'} points to default directory at all times |
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292 | # 06-Mar-1996 Charles Bailey bailey@genetics.upenn.edu |
293 | # Note: Use of Cwd::chdir() causes the logical name PWD to be defined |
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294 | # in the process logical name table as the default device and directory |
295 | # seen by Perl. This may not be the same as the default device |
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296 | # and directory seen by DCL after Perl exits, since the effects |
297 | # the CRTL chdir() function persist only until Perl exits. |
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298 | |
299 | sub _vms_cwd { |
300 | return $ENV{'DEFAULT'} |
301 | } |
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302 | |
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303 | sub _os2_cwd { |
304 | $ENV{'PWD'} = `cmd /c cd`; |
305 | chop $ENV{'PWD'}; |
306 | $ENV{'PWD'} =~ s:\\:/:g ; |
307 | return $ENV{'PWD'}; |
308 | } |
309 | |
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310 | *_NT_cwd = \&_os2_cwd unless defined &_NT_cwd; |
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311 | |
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312 | sub _msdos_cwd { |
313 | $ENV{'PWD'} = `command /c cd`; |
314 | chop $ENV{'PWD'}; |
315 | $ENV{'PWD'} =~ s:\\:/:g ; |
316 | return $ENV{'PWD'}; |
317 | } |
318 | |
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319 | { |
320 | local $^W = 0; # assignments trigger 'subroutine redefined' warning |
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321 | |
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322 | if ($^O eq 'VMS') { |
323 | *cwd = \&_vms_cwd; |
324 | *getcwd = \&_vms_cwd; |
325 | *fastcwd = \&_vms_cwd; |
326 | *fastgetcwd = \&_vms_cwd; |
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327 | *abs_path = \&fast_abspath; |
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328 | } |
329 | elsif ($^O eq 'NT' or $^O eq 'MSWin32') { |
330 | # We assume that &_NT_cwd is defined as an XSUB or in the core. |
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331 | *cwd = \&_NT_cwd; |
332 | *getcwd = \&_NT_cwd; |
333 | *fastcwd = \&_NT_cwd; |
334 | *fastgetcwd = \&_NT_cwd; |
335 | *abs_path = \&fast_abspath; |
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336 | } |
337 | elsif ($^O eq 'os2') { |
338 | # sys_cwd may keep the builtin command |
339 | *cwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd; |
340 | *getcwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd; |
341 | *fastgetcwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd; |
342 | *fastcwd = defined &sys_cwd ? \&sys_cwd : \&_os2_cwd; |
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343 | *abs_path = \&fast_abspath; |
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344 | } |
345 | elsif ($^O eq 'msdos') { |
346 | *cwd = \&_msdos_cwd; |
347 | *getcwd = \&_msdos_cwd; |
348 | *fastgetcwd = \&_msdos_cwd; |
349 | *fastcwd = \&_msdos_cwd; |
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350 | *abs_path = \&fast_abspath; |
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351 | } |
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352 | } |
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353 | |
354 | # package main; eval join('',<DATA>) || die $@; # quick test |
355 | |
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356 | 1; |
357 | |
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358 | __END__ |
359 | BEGIN { import Cwd qw(:DEFAULT chdir); } |
360 | print join("\n", cwd, getcwd, fastcwd, ""); |
361 | chdir('..'); |
362 | print join("\n", cwd, getcwd, fastcwd, ""); |
363 | print "$ENV{PWD}\n"; |