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1 | package Cwd; |
2 | require 5.000; |
3 | require Exporter; |
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4 | require Config; |
5 | |
6 | # Use osname for portability switches (doubled to cheaply avoid -w warning) |
7 | my $osname = $Config::Config{'osname'} || $Config::Config{'osname'}; |
8 | |
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9 | |
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10 | =head1 NAME |
11 | |
12 | getcwd - get pathname of current working directory |
13 | |
14 | =head1 SYNOPSIS |
15 | |
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16 | use Cwd; |
17 | $dir = cwd; |
18 | |
19 | use Cwd; |
20 | $dir = getcwd; |
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21 | |
22 | use Cwd; |
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23 | $dir = fastgetcwd; |
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24 | |
25 | use Cwd 'chdir'; |
26 | chdir "/tmp"; |
27 | print $ENV{'PWD'}; |
28 | |
29 | =head1 DESCRIPTION |
30 | |
31 | The getcwd() function re-implements the getcwd(3) (or getwd(3)) functions |
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32 | in Perl. |
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33 | |
34 | The fastgetcwd() function looks the same as getcwd(), but runs faster. |
35 | It's also more dangerous because you might conceivably chdir() out of a |
36 | directory that you can't chdir() back into. |
37 | |
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38 | The cwd() function looks the same as getcwd and fastgetcwd but is |
39 | implemented using the most natural and safe form for the current |
40 | architecture. For most systems it is identical to `pwd` (but without |
41 | the trailing line terminator). It is recommended that cwd (or another |
42 | *cwd() function) is used in I<all> code to ensure portability. |
43 | |
44 | If you ask to override your chdir() built-in function, then your PWD |
45 | environment variable will be kept up to date. (See |
46 | L<perlsub/Overriding builtin functions>.) Note that it will only be |
47 | kept up to date it all packages which use chdir import it from Cwd. |
48 | |
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49 | =cut |
50 | |
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51 | @ISA = qw(Exporter); |
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52 | @EXPORT = qw(cwd getcwd fastcwd); |
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53 | @EXPORT_OK = qw(chdir); |
54 | |
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55 | # use strict; |
56 | |
57 | sub _backtick_pwd { # The 'natural and safe form' for UNIX (pwd may be setuid root) |
58 | my $cwd; |
59 | chop($cwd = `pwd`); |
60 | $cwd; |
61 | } |
62 | |
63 | # Since some ports may predefine cwd internally (e.g., NT) |
64 | # we take care not to override an existing definition for cwd(). |
65 | |
66 | *cwd = \&_backtick_pwd unless defined &cwd; |
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67 | |
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68 | |
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69 | # By Brandon S. Allbery |
70 | # |
71 | # Usage: $cwd = getcwd(); |
72 | |
73 | sub getcwd |
74 | { |
75 | my($dotdots, $cwd, @pst, @cst, $dir, @tst); |
76 | |
77 | unless (@cst = stat('.')) |
78 | { |
79 | warn "stat(.): $!"; |
80 | return ''; |
81 | } |
82 | $cwd = ''; |
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83 | $dotdots = ''; |
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84 | do |
85 | { |
86 | $dotdots .= '/' if $dotdots; |
87 | $dotdots .= '..'; |
88 | @pst = @cst; |
89 | unless (opendir(PARENT, $dotdots)) |
90 | { |
91 | warn "opendir($dotdots): $!"; |
92 | return ''; |
93 | } |
94 | unless (@cst = stat($dotdots)) |
95 | { |
96 | warn "stat($dotdots): $!"; |
97 | closedir(PARENT); |
98 | return ''; |
99 | } |
100 | if ($pst[0] == $cst[0] && $pst[1] == $cst[1]) |
101 | { |
102 | $dir = ''; |
103 | } |
104 | else |
105 | { |
106 | do |
107 | { |
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108 | unless (defined ($dir = readdir(PARENT))) |
109 | { |
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110 | warn "readdir($dotdots): $!"; |
111 | closedir(PARENT); |
112 | return ''; |
113 | } |
114 | unless (@tst = lstat("$dotdots/$dir")) |
115 | { |
116 | warn "lstat($dotdots/$dir): $!"; |
117 | closedir(PARENT); |
118 | return ''; |
119 | } |
120 | } |
121 | while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] || |
122 | $tst[1] != $pst[1]); |
123 | } |
124 | $cwd = "$dir/$cwd"; |
125 | closedir(PARENT); |
126 | } while ($dir); |
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127 | chop($cwd); # drop the trailing / |
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128 | $cwd; |
129 | } |
130 | |
131 | |
132 | |
133 | # By John Bazik |
134 | # |
135 | # Usage: $cwd = &fastcwd; |
136 | # |
137 | # This is a faster version of getcwd. It's also more dangerous because |
138 | # you might chdir out of a directory that you can't chdir back into. |
139 | |
140 | sub fastcwd { |
141 | my($odev, $oino, $cdev, $cino, $tdev, $tino); |
142 | my(@path, $path); |
143 | local(*DIR); |
144 | |
145 | ($cdev, $cino) = stat('.'); |
146 | for (;;) { |
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147 | my $direntry; |
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148 | ($odev, $oino) = ($cdev, $cino); |
149 | chdir('..'); |
150 | ($cdev, $cino) = stat('.'); |
151 | last if $odev == $cdev && $oino == $cino; |
152 | opendir(DIR, '.'); |
153 | for (;;) { |
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154 | $direntry = readdir(DIR); |
155 | next if $direntry eq '.'; |
156 | next if $direntry eq '..'; |
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157 | |
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158 | last unless defined $direntry; |
159 | ($tdev, $tino) = lstat($direntry); |
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160 | last unless $tdev != $odev || $tino != $oino; |
161 | } |
162 | closedir(DIR); |
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163 | unshift(@path, $direntry); |
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164 | } |
165 | chdir($path = '/' . join('/', @path)); |
166 | $path; |
167 | } |
168 | |
169 | |
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170 | # Keeps track of current working directory in PWD environment var |
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171 | # Usage: |
172 | # use Cwd 'chdir'; |
173 | # chdir $newdir; |
174 | |
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175 | my $chdir_init = 0; |
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176 | |
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177 | sub chdir_init { |
178 | if ($ENV{'PWD'} and $osname ne 'os2') { |
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179 | my($dd,$di) = stat('.'); |
180 | my($pd,$pi) = stat($ENV{'PWD'}); |
181 | if (!defined $dd or !defined $pd or $di != $pi or $dd != $pd) { |
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182 | $ENV{'PWD'} = cwd(); |
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183 | } |
184 | } |
185 | else { |
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186 | $ENV{'PWD'} = cwd(); |
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187 | } |
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188 | # Strip an automounter prefix (where /tmp_mnt/foo/bar == /foo/bar) |
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189 | if ($ENV{'PWD'} =~ m|(/[^/]+(/[^/]+/[^/]+))(.*)|) { |
190 | my($pd,$pi) = stat($2); |
191 | my($dd,$di) = stat($1); |
192 | if (defined $pd and defined $dd and $di == $pi and $dd == $pd) { |
193 | $ENV{'PWD'}="$2$3"; |
194 | } |
195 | } |
196 | $chdir_init = 1; |
197 | } |
198 | |
199 | sub chdir { |
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200 | my $newdir = shift || ''; # allow for no arg (chdir to HOME dir) |
201 | $newdir =~ s|///*|/|g; |
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202 | chdir_init() unless $chdir_init; |
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203 | return 0 unless CORE::chdir $newdir; |
204 | if ($osname eq 'VMS') { return $ENV{'PWD'} = $ENV{'DEFAULT'} } |
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205 | |
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206 | if ($newdir =~ m#^/#) { |
207 | $ENV{'PWD'} = $newdir; |
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208 | } else { |
209 | my @curdir = split(m#/#,$ENV{'PWD'}); |
210 | @curdir = ('') unless @curdir; |
211 | my $component; |
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212 | foreach $component (split(m#/#, $newdir)) { |
213 | next if $component eq '.'; |
214 | pop(@curdir),next if $component eq '..'; |
215 | push(@curdir,$component); |
216 | } |
217 | $ENV{'PWD'} = join('/',@curdir) || '/'; |
218 | } |
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219 | 1; |
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220 | } |
221 | |
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222 | |
223 | # --- PORTING SECTION --- |
224 | |
225 | # VMS: $ENV{'DEFAULT'} points to default directory at all times |
226 | # 08-Dec-1994 Charles Bailey bailey@genetics.upenn.edu |
227 | # Note: Use of Cwd::getcwd() or Cwd::chdir() (but not Cwd::fastcwd()) |
228 | # causes the logical name PWD to be defined in the process |
229 | # logical name table as the default device and directory |
230 | # seen by Perl. This may not be the same as the default device |
231 | # and directory seen by DCL after Perl exits, since the effects |
232 | # the CRTL chdir() function persist only until Perl exits. |
233 | # This does not apply to other systems (where only chdir() sets PWD). |
234 | |
235 | sub _vms_cwd { |
236 | return $ENV{'DEFAULT'} |
237 | } |
238 | sub _vms_pwd { |
239 | return $ENV{'PWD'} = $ENV{'DEFAULT'} |
240 | } |
241 | sub _os2_cwd { |
242 | $ENV{'PWD'} = `cmd /c cd`; |
243 | chop $ENV{'PWD'}; |
244 | $ENV{'PWD'} =~ s:\\:/:g ; |
245 | return $ENV{'PWD'}; |
246 | } |
247 | |
248 | if ($osname eq 'VMS') { |
249 | |
250 | *cwd = \&_vms_pwd; |
251 | *getcwd = \&_vms_pwd; |
252 | *fastgetcwd = \&_vms_cwd; |
253 | } |
254 | elsif ($osname eq 'NT') { |
255 | |
256 | *getcwd = \&cwd; |
257 | *fastgetcwd = \&cwd; |
258 | } |
259 | elsif ($osname eq 'os2') { |
260 | *cwd = \&_os2_cwd; |
261 | *getcwd = \&_os2_cwd; |
262 | *fastgetcwd = \&_os2_cwd; |
263 | *fastcwd = \&_os2_cwd; |
264 | } |
265 | |
266 | # package main; eval join('',<DATA>) || die $@; # quick test |
267 | |
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268 | 1; |
269 | |
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270 | __END__ |
271 | BEGIN { import Cwd qw(:DEFAULT chdir); } |
272 | print join("\n", cwd, getcwd, fastcwd, ""); |
273 | chdir('..'); |
274 | print join("\n", cwd, getcwd, fastcwd, ""); |
275 | print "$ENV{PWD}\n"; |