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