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package File::stat; | |
use 5.006; | |
use strict; | |
use warnings; | |
use warnings::register; | |
use Carp; | |
use constant _IS_CYGWIN => $^O eq "cygwin"; | |
BEGIN { *warnif = \&warnings::warnif } | |
our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS); | |
our $VERSION = '1.09'; | |
our @fields; | |
our ( $st_dev, $st_ino, $st_mode, | |
$st_nlink, $st_uid, $st_gid, | |
$st_rdev, $st_size, | |
$st_atime, $st_mtime, $st_ctime, | |
$st_blksize, $st_blocks | |
); | |
BEGIN { | |
use Exporter (); | |
@EXPORT = qw(stat lstat); | |
@fields = qw( $st_dev $st_ino $st_mode | |
$st_nlink $st_uid $st_gid | |
$st_rdev $st_size | |
$st_atime $st_mtime $st_ctime | |
$st_blksize $st_blocks | |
); | |
@EXPORT_OK = ( @fields, "stat_cando" ); | |
%EXPORT_TAGS = ( FIELDS => [ @fields, @EXPORT ] ); | |
} | |
use Fcntl qw(S_IRUSR S_IWUSR S_IXUSR); | |
BEGIN { | |
# These constants will croak on use if the platform doesn't define | |
# them. It's important to avoid inflicting that on the user. | |
no strict 'refs'; | |
for (qw(suid sgid svtx)) { | |
my $val = eval { &{"Fcntl::S_I\U$_"} }; | |
*{"_$_"} = defined $val ? sub { $_[0] & $val ? 1 : "" } : sub { "" }; | |
} | |
for (qw(SOCK CHR BLK REG DIR LNK)) { | |
*{"S_IS$_"} = defined eval { &{"Fcntl::S_IF$_"} } | |
? \&{"Fcntl::S_IS$_"} : sub { "" }; | |
} | |
# FIFO flag and macro don't quite follow the S_IF/S_IS pattern above | |
# RT #111638 | |
*{"S_ISFIFO"} = defined &Fcntl::S_IFIFO | |
? \&Fcntl::S_ISFIFO : sub { "" }; | |
} | |
# from doio.c | |
sub _ingroup { | |
my ($gid, $eff) = @_; | |
# I am assuming that since VMS doesn't have getgroups(2), $) will | |
# always only contain a single entry. | |
$^O eq "VMS" and return $_[0] == $); | |
my ($egid, @supp) = split " ", $); | |
my ($rgid) = split " ", $(; | |
$gid == ($eff ? $egid : $rgid) and return 1; | |
grep $gid == $_, @supp and return 1; | |
return ""; | |
} | |
# VMS uses the Unix version of the routine, even though this is very | |
# suboptimal. VMS has a permissions structure that doesn't really fit | |
# into struct stat, and unlike on Win32 the normal -X operators respect | |
# that, but unfortunately by the time we get here we've already lost the | |
# information we need. It looks to me as though if we were to preserve | |
# the st_devnam entry of vmsish.h's fake struct stat (which actually | |
# holds the filename) it might be possible to do this right, but both | |
# getting that value out of the struct (perl's stat doesn't return it) | |
# and interpreting it later would require this module to have an XS | |
# component (at which point we might as well just call Perl_cando and | |
# have done with it). | |
if (grep $^O eq $_, qw/os2 MSWin32 dos/) { | |
# from doio.c | |
*cando = sub { ($_[0][2] & $_[1]) ? 1 : "" }; | |
} | |
else { | |
# from doio.c | |
*cando = sub { | |
my ($s, $mode, $eff) = @_; | |
my $uid = $eff ? $> : $<; | |
my ($stmode, $stuid, $stgid) = @$s[2,4,5]; | |
# This code basically assumes that the rwx bits of the mode are | |
# the 0777 bits, but so does Perl_cando. | |
if (_IS_CYGWIN ? _ingroup(544, $eff) : ($uid == 0 && $^O ne "VMS")) { | |
# If we're root on unix | |
# not testing for executable status => all file tests are true | |
return 1 if !($mode & 0111); | |
# testing for executable status => | |
# for a file, any x bit will do | |
# for a directory, always true | |
return 1 if $stmode & 0111 || S_ISDIR($stmode); | |
return ""; | |
} | |
if ($stuid == $uid) { | |
$stmode & $mode and return 1; | |
} | |
elsif (_ingroup($stgid, $eff)) { | |
$stmode & ($mode >> 3) and return 1; | |
} | |
else { | |
$stmode & ($mode >> 6) and return 1; | |
} | |
return ""; | |
}; | |
} | |
# alias for those who don't like objects | |
*stat_cando = \&cando; | |
my %op = ( | |
r => sub { cando($_[0], S_IRUSR, 1) }, | |
w => sub { cando($_[0], S_IWUSR, 1) }, | |
x => sub { cando($_[0], S_IXUSR, 1) }, | |
o => sub { $_[0][4] == $> }, | |
R => sub { cando($_[0], S_IRUSR, 0) }, | |
W => sub { cando($_[0], S_IWUSR, 0) }, | |
X => sub { cando($_[0], S_IXUSR, 0) }, | |
O => sub { $_[0][4] == $< }, | |
e => sub { 1 }, | |
z => sub { $_[0][7] == 0 }, | |
s => sub { $_[0][7] }, | |
f => sub { S_ISREG ($_[0][2]) }, | |
d => sub { S_ISDIR ($_[0][2]) }, | |
l => sub { S_ISLNK ($_[0][2]) }, | |
p => sub { S_ISFIFO($_[0][2]) }, | |
S => sub { S_ISSOCK($_[0][2]) }, | |
b => sub { S_ISBLK ($_[0][2]) }, | |
c => sub { S_ISCHR ($_[0][2]) }, | |
u => sub { _suid($_[0][2]) }, | |
g => sub { _sgid($_[0][2]) }, | |
k => sub { _svtx($_[0][2]) }, | |
M => sub { ($^T - $_[0][9] ) / 86400 }, | |
C => sub { ($^T - $_[0][10]) / 86400 }, | |
A => sub { ($^T - $_[0][8] ) / 86400 }, | |
); | |
use constant HINT_FILETEST_ACCESS => 0x00400000; | |
# we need fallback=>1 or stringifying breaks | |
use overload | |
fallback => 1, | |
-X => sub { | |
my ($s, $op) = @_; | |
if (index("rwxRWX", $op) >= 0) { | |
(caller 0)[8] & HINT_FILETEST_ACCESS | |
and warnif("File::stat ignores use filetest 'access'"); | |
$^O eq "VMS" and warnif("File::stat ignores VMS ACLs"); | |
# It would be nice to have a warning about using -l on a | |
# non-lstat, but that would require an extra member in the | |
# object. | |
} | |
if ($op{$op}) { | |
return $op{$op}->($_[0]); | |
} | |
else { | |
croak "-$op is not implemented on a File::stat object"; | |
} | |
}; | |
# Class::Struct forbids use of @ISA | |
sub import { goto &Exporter::import } | |
use Class::Struct qw(struct); | |
struct 'File::stat' => [ | |
map { $_ => '$' } qw{ | |
dev ino mode nlink uid gid rdev size | |
atime mtime ctime blksize blocks | |
} | |
]; | |
sub populate (@) { | |
return unless @_; | |
my $stob = new(); | |
@$stob = ( | |
$st_dev, $st_ino, $st_mode, $st_nlink, $st_uid, $st_gid, $st_rdev, | |
$st_size, $st_atime, $st_mtime, $st_ctime, $st_blksize, $st_blocks ) | |
= @_; | |
return $stob; | |
} | |
sub lstat ($) { populate(CORE::lstat(shift)) } | |
sub stat ($) { | |
my $arg = shift; | |
my $st = populate(CORE::stat $arg); | |
return $st if defined $st; | |
my $fh; | |
{ | |
local $!; | |
no strict 'refs'; | |
require Symbol; | |
$fh = \*{ Symbol::qualify( $arg, caller() )}; | |
return unless defined fileno $fh; | |
} | |
return populate(CORE::stat $fh); | |
} | |
1; | |
__END__ | |
=head1 NAME | |
File::stat - by-name interface to Perl's built-in stat() functions | |
=head1 SYNOPSIS | |
use File::stat; | |
$st = stat($file) or die "No $file: $!"; | |
if ( ($st->mode & 0111) && $st->nlink > 1) ) { | |
print "$file is executable with lotsa links\n"; | |
} | |
if ( -x $st ) { | |
print "$file is executable\n"; | |
} | |
use Fcntl "S_IRUSR"; | |
if ( $st->cando(S_IRUSR, 1) ) { | |
print "My effective uid can read $file\n"; | |
} | |
use File::stat qw(:FIELDS); | |
stat($file) or die "No $file: $!"; | |
if ( ($st_mode & 0111) && ($st_nlink > 1) ) { | |
print "$file is executable with lotsa links\n"; | |
} | |
=head1 DESCRIPTION | |
This module's default exports override the core stat() | |
and lstat() functions, replacing them with versions that return | |
"File::stat" objects. This object has methods that | |
return the similarly named structure field name from the | |
stat(2) function; namely, | |
dev, | |
ino, | |
mode, | |
nlink, | |
uid, | |
gid, | |
rdev, | |
size, | |
atime, | |
mtime, | |
ctime, | |
blksize, | |
and | |
blocks. | |
As of version 1.02 (provided with perl 5.12) the object provides C<"-X"> | |
overloading, so you can call filetest operators (C<-f>, C<-x>, and so | |
on) on it. It also provides a C<< ->cando >> method, called like | |
$st->cando( ACCESS, EFFECTIVE ) | |
where I<ACCESS> is one of C<S_IRUSR>, C<S_IWUSR> or C<S_IXUSR> from the | |
L<Fcntl|Fcntl> module, and I<EFFECTIVE> indicates whether to use | |
effective (true) or real (false) ids. The method interprets the C<mode>, | |
C<uid> and C<gid> fields, and returns whether or not the current process | |
would be allowed the specified access. | |
If you don't want to use the objects, you may import the C<< ->cando >> | |
method into your namespace as a regular function called C<stat_cando>. | |
This takes an arrayref containing the return values of C<stat> or | |
C<lstat> as its first argument, and interprets it for you. | |
You may also import all the structure fields directly into your namespace | |
as regular variables using the :FIELDS import tag. (Note that this still | |
overrides your stat() and lstat() functions.) Access these fields as | |
variables named with a preceding C<st_> in front their method names. | |
Thus, C<$stat_obj-E<gt>dev()> corresponds to $st_dev if you import | |
the fields. | |
To access this functionality without the core overrides, | |
pass the C<use> an empty import list, and then access | |
function functions with their full qualified names. | |
On the other hand, the built-ins are still available | |
via the C<CORE::> pseudo-package. | |
=head1 BUGS | |
As of Perl 5.8.0 after using this module you cannot use the implicit | |
C<$_> or the special filehandle C<_> with stat() or lstat(), trying | |
to do so leads into strange errors. The workaround is for C<$_> to | |
be explicit | |
my $stat_obj = stat $_; | |
and for C<_> to explicitly populate the object using the unexported | |
and undocumented populate() function with CORE::stat(): | |
my $stat_obj = File::stat::populate(CORE::stat(_)); | |
=head1 ERRORS | |
=over 4 | |
=item -%s is not implemented on a File::stat object | |
The filetest operators C<-t>, C<-T> and C<-B> are not implemented, as | |
they require more information than just a stat buffer. | |
=back | |
=head1 WARNINGS | |
These can all be disabled with | |
no warnings "File::stat"; | |
=over 4 | |
=item File::stat ignores use filetest 'access' | |
You have tried to use one of the C<-rwxRWX> filetests with C<use | |
filetest 'access'> in effect. C<File::stat> will ignore the pragma, and | |
just use the information in the C<mode> member as usual. | |
=item File::stat ignores VMS ACLs | |
VMS systems have a permissions structure that cannot be completely | |
represented in a stat buffer, and unlike on other systems the builtin | |
filetest operators respect this. The C<File::stat> overloads, however, | |
do not, since the information required is not available. | |
=back | |
=head1 NOTE | |
While this class is currently implemented using the Class::Struct | |
module to build a struct-like class, you shouldn't rely upon this. | |
=head1 AUTHOR | |
Tom Christiansen | |