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1 | package File::stat; |
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2 | use 5.006; |
3 | |
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4 | use strict; |
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5 | use warnings; |
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6 | use warnings::register; |
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7 | use Carp; |
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8 | |
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9 | BEGIN { *warnif = \&warnings::warnif } |
10 | |
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11 | our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS); |
12 | |
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13 | our $VERSION = '1.02'; |
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14 | |
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15 | my @fields; |
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16 | BEGIN { |
17 | use Exporter (); |
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18 | @EXPORT = qw(stat lstat); |
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19 | @fields = qw( $st_dev $st_ino $st_mode |
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20 | $st_nlink $st_uid $st_gid |
21 | $st_rdev $st_size |
22 | $st_atime $st_mtime $st_ctime |
23 | $st_blksize $st_blocks |
24 | ); |
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25 | @EXPORT_OK = ( @fields, "stat_cando" ); |
26 | %EXPORT_TAGS = ( FIELDS => [ @fields, @EXPORT ] ); |
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27 | } |
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28 | use vars @fields; |
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29 | |
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30 | use Fcntl qw(S_IRUSR S_IWUSR S_IXUSR); |
31 | |
32 | BEGIN { |
33 | # These constants will croak on use if the platform doesn't define |
34 | # them. It's important to avoid inflicting that on the user. |
35 | no strict 'refs'; |
36 | for (qw(suid sgid svtx)) { |
37 | my $val = eval { &{"Fcntl::S_I\U$_"} }; |
38 | *{"_$_"} = defined $val ? sub { $_[0] & $val ? 1 : "" } : sub { "" }; |
39 | } |
40 | for (qw(SOCK CHR BLK REG DIR FIFO LNK)) { |
41 | *{"S_IS$_"} = defined eval { &{"Fcntl::S_IF$_"} } |
42 | ? \&{"Fcntl::S_IS$_"} : sub { "" }; |
43 | } |
44 | } |
45 | |
46 | # from doio.c |
47 | sub _ingroup { |
48 | |
49 | $^O eq "MacOS" and return 1; |
50 | |
51 | my ($gid, $eff) = @_; |
52 | |
53 | # I am assuming that since VMS doesn't have getgroups(2), $) will |
54 | # always only contain a single entry. |
55 | $^O eq "VMS" and return $_[0] == $); |
56 | |
57 | my ($egid, @supp) = split " ", $); |
58 | my ($rgid) = split " ", $(; |
59 | |
60 | $gid == ($eff ? $egid : $rgid) and return 1; |
61 | grep $gid == $_, @supp and return 1; |
62 | |
63 | return ""; |
64 | } |
65 | |
66 | # VMS uses the Unix version of the routine, even though this is very |
67 | # suboptimal. VMS has a permissions structure that doesn't really fit |
68 | # into struct stat, and unlike on Win32 the normal -X operators respect |
69 | # that, but unfortunately by the time we get here we've already lost the |
70 | # information we need. It looks to me as though if we were to preserve |
71 | # the st_devnam entry of vmsish.h's fake struct stat (which actually |
72 | # holds the filename) it might be possible to do this right, but both |
73 | # getting that value out of the struct (perl's stat doesn't return it) |
74 | # and interpreting it later would require this module to have an XS |
75 | # component (at which point we might as well just call Perl_cando and |
76 | # have done with it). |
77 | |
78 | if (grep $^O eq $_, qw/os2 MSWin32 dos/) { |
79 | |
80 | # from doio.c |
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81 | *cando = sub { ($_[0][2] & $_[1]) ? 1 : "" }; |
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82 | } |
83 | else { |
84 | |
85 | # from doio.c |
86 | *cando = sub { |
87 | my ($s, $mode, $eff) = @_; |
88 | my $uid = $eff ? $> : $<; |
89 | |
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90 | $^O ne "VMS" and $uid == 0 and return 1; |
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91 | |
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92 | my ($stmode, $stuid, $stgid) = @$s[2,4,5]; |
93 | |
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94 | # This code basically assumes that the rwx bits of the mode are |
95 | # the 0777 bits, but so does Perl_cando. |
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96 | if ($stuid == $uid) { |
97 | $stmode & $mode and return 1; |
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98 | } |
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99 | elsif (_ingroup($stgid, $eff)) { |
100 | $stmode & ($mode >> 3) and return 1; |
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101 | } |
102 | else { |
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103 | $stmode & ($mode >> 6) and return 1; |
448e77d7 |
104 | } |
105 | return ""; |
106 | }; |
107 | } |
108 | |
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109 | # alias for those who don't like objects |
110 | *stat_cando = \&cando; |
111 | |
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112 | my %op = ( |
113 | r => sub { cando($_[0], S_IRUSR, 1) }, |
114 | w => sub { cando($_[0], S_IWUSR, 1) }, |
115 | x => sub { cando($_[0], S_IXUSR, 1) }, |
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116 | o => sub { $_[0][4] == $> }, |
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117 | |
118 | R => sub { cando($_[0], S_IRUSR, 0) }, |
119 | W => sub { cando($_[0], S_IWUSR, 0) }, |
120 | X => sub { cando($_[0], S_IXUSR, 0) }, |
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121 | O => sub { $_[0][4] == $< }, |
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122 | |
123 | e => sub { 1 }, |
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124 | z => sub { $_[0][7] == 0 }, |
125 | s => sub { $_[0][7] }, |
126 | |
127 | f => sub { S_ISREG ($_[0][2]) }, |
128 | d => sub { S_ISDIR ($_[0][2]) }, |
129 | l => sub { S_ISLNK ($_[0][2]) }, |
130 | p => sub { S_ISFIFO($_[0][2]) }, |
131 | S => sub { S_ISSOCK($_[0][2]) }, |
132 | b => sub { S_ISBLK ($_[0][2]) }, |
133 | c => sub { S_ISCHR ($_[0][2]) }, |
134 | |
135 | u => sub { _suid($_[0][2]) }, |
136 | g => sub { _sgid($_[0][2]) }, |
137 | k => sub { _svtx($_[0][2]) }, |
138 | |
139 | M => sub { ($^T - $_[0][9] ) / 86400 }, |
140 | C => sub { ($^T - $_[0][10]) / 86400 }, |
141 | A => sub { ($^T - $_[0][8] ) / 86400 }, |
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142 | ); |
143 | |
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144 | use constant HINT_FILETEST_ACCESS => 0x00400000; |
145 | |
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146 | # we need fallback=>1 or stringifying breaks |
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147 | use overload |
148 | fallback => 1, |
149 | -X => sub { |
150 | my ($s, $op) = @_; |
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151 | |
152 | if (index "rwxRWX", $op) { |
153 | (caller 0)[8] & HINT_FILETEST_ACCESS |
154 | and warnif("File::stat ignores use filetest 'access'"); |
155 | |
156 | $^O eq "VMS" and warnif("File::stat ignores VMS ACLs"); |
157 | |
158 | # It would be nice to have a warning about using -l on a |
159 | # non-lstat, but that would require an extra member in the |
160 | # object. |
161 | } |
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162 | |
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163 | if ($op{$op}) { |
164 | return $op{$op}->($_[0]); |
165 | } |
166 | else { |
167 | croak "-$op is not implemented on a File::stat object"; |
168 | } |
169 | }; |
170 | |
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171 | # Class::Struct forbids use of @ISA |
172 | sub import { goto &Exporter::import } |
173 | |
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174 | use Class::Struct qw(struct); |
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175 | struct 'File::stat' => [ |
176 | map { $_ => '$' } qw{ |
177 | dev ino mode nlink uid gid rdev size |
178 | atime mtime ctime blksize blocks |
179 | } |
180 | ]; |
181 | |
182 | sub populate (@) { |
183 | return unless @_; |
184 | my $stob = new(); |
185 | @$stob = ( |
186 | $st_dev, $st_ino, $st_mode, $st_nlink, $st_uid, $st_gid, $st_rdev, |
187 | $st_size, $st_atime, $st_mtime, $st_ctime, $st_blksize, $st_blocks ) |
188 | = @_; |
189 | return $stob; |
190 | } |
191 | |
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192 | sub lstat ($) { populate(CORE::lstat(shift)) } |
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193 | |
194 | sub stat ($) { |
195 | my $arg = shift; |
196 | my $st = populate(CORE::stat $arg); |
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197 | return $st if defined $st; |
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198 | my $fh; |
199 | { |
200 | local $!; |
201 | no strict 'refs'; |
202 | require Symbol; |
83716b1e |
203 | $fh = \*{ Symbol::qualify( $arg, caller() )}; |
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204 | return unless defined fileno $fh; |
205 | } |
206 | return populate(CORE::stat $fh); |
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207 | } |
208 | |
209 | 1; |
210 | __END__ |
211 | |
212 | =head1 NAME |
213 | |
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214 | File::stat - by-name interface to Perl's built-in stat() functions |
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215 | |
216 | =head1 SYNOPSIS |
217 | |
218 | use File::stat; |
219 | $st = stat($file) or die "No $file: $!"; |
220 | if ( ($st->mode & 0111) && $st->nlink > 1) ) { |
221 | print "$file is executable with lotsa links\n"; |
222 | } |
223 | |
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224 | if ( -x $st ) { |
225 | print "$file is executable\n"; |
226 | } |
227 | |
228 | use Fcntl "S_IRUSR"; |
229 | if ( $st->cando(S_IRUSR, 1) ) { |
230 | print "My effective uid can read $file\n"; |
231 | } |
232 | |
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233 | use File::stat qw(:FIELDS); |
234 | stat($file) or die "No $file: $!"; |
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235 | if ( ($st_mode & 0111) && ($st_nlink > 1) ) { |
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236 | print "$file is executable with lotsa links\n"; |
237 | } |
238 | |
239 | =head1 DESCRIPTION |
240 | |
241 | This module's default exports override the core stat() |
242 | and lstat() functions, replacing them with versions that return |
243 | "File::stat" objects. This object has methods that |
244 | return the similarly named structure field name from the |
245 | stat(2) function; namely, |
246 | dev, |
247 | ino, |
248 | mode, |
249 | nlink, |
250 | uid, |
251 | gid, |
252 | rdev, |
253 | size, |
254 | atime, |
255 | mtime, |
256 | ctime, |
257 | blksize, |
258 | and |
259 | blocks. |
260 | |
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261 | As of version 1.02 (provided with perl 5.12) the object provides C<"-X"> |
262 | overloading, so you can call filetest operators (C<-f>, C<-x>, and so |
263 | on) on it. It also provides a C<< ->cando >> method, called like |
264 | |
265 | $st->cando( ACCESS, EFFECTIVE ) |
266 | |
267 | where I<ACCESS> is one of C<S_IRUSR>, C<S_IWUSR> or C<S_IXUSR> from the |
268 | L<Fcntl|Fcntl> module, and I<EFFECTIVE> indicates whether to use |
269 | effective (true) or real (false) ids. The method interprets the C<mode>, |
270 | C<uid> and C<gid> fields, and returns whether or not the current process |
271 | would be allowed the specified access. |
272 | |
273 | If you don't want to use the objects, you may import the C<< ->cando >> |
274 | method into your namespace as a regular function called C<stat_cando>. |
275 | This takes an arrayref containing the return values of C<stat> or |
276 | C<lstat> as its first argument, and interprets it for you. |
277 | |
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278 | You may also import all the structure fields directly into your namespace |
279 | as regular variables using the :FIELDS import tag. (Note that this still |
280 | overrides your stat() and lstat() functions.) Access these fields as |
281 | variables named with a preceding C<st_> in front their method names. |
282 | Thus, C<$stat_obj-E<gt>dev()> corresponds to $st_dev if you import |
283 | the fields. |
284 | |
285 | To access this functionality without the core overrides, |
286 | pass the C<use> an empty import list, and then access |
287 | function functions with their full qualified names. |
288 | On the other hand, the built-ins are still available |
289 | via the C<CORE::> pseudo-package. |
290 | |
5c4d9947 |
291 | =head1 BUGS |
292 | |
293 | As of Perl 5.8.0 after using this module you cannot use the implicit |
294 | C<$_> or the special filehandle C<_> with stat() or lstat(), trying |
295 | to do so leads into strange errors. The workaround is for C<$_> to |
296 | be explicit |
297 | |
298 | my $stat_obj = stat $_; |
299 | |
300 | and for C<_> to explicitly populate the object using the unexported |
301 | and undocumented populate() function with CORE::stat(): |
302 | |
303 | my $stat_obj = File::stat::populate(CORE::stat(_)); |
304 | |
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305 | =head1 ERRORS |
306 | |
307 | =over 4 |
308 | |
309 | =item -%s is not implemented on a File::stat object |
310 | |
311 | The filetest operators C<-t>, C<-T> and C<-B> are not implemented, as |
312 | they require more information than just a stat buffer. |
313 | |
314 | =back |
315 | |
316 | =head1 WARNINGS |
317 | |
318 | These can all be disabled with |
319 | |
320 | no warnings "File::stat"; |
321 | |
322 | =over 4 |
323 | |
324 | =item File::stat ignores use filetest 'access' |
325 | |
326 | You have tried to use one of the C<-rwxRWX> filetests with C<use |
327 | filetest 'access'> in effect. C<File::stat> will ignore the pragma, and |
328 | just use the information in the C<mode> member as usual. |
329 | |
330 | =item File::stat ignores VMS ACLs |
331 | |
332 | VMS systems have a permissions structure that cannot be completely |
333 | represented in a stat buffer, and unlike on other systems the builtin |
334 | filetest operators respect this. The C<File::stat> overloads, however, |
335 | do not, since the information required is not available. |
336 | |
337 | =back |
338 | |
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339 | =head1 NOTE |
340 | |
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341 | While this class is currently implemented using the Class::Struct |
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342 | module to build a struct-like class, you shouldn't rely upon this. |
343 | |
344 | =head1 AUTHOR |
345 | |
346 | Tom Christiansen |