Two comments:
02000 is 1024 in base 8; the leading 0 indicates octal much as leading 0x
indicates hex.
$a & $b returns the number with bits in common, so we expect 1024 & 1024 to
equal 1024 (or 02000 & 02755, the latter being a realistic file mode; note
these are in octal). This will be true in boolean context.
Hope this helps;
Anne
2011. 10. 29. 오후 10:07에 "Daniel Patrick Sullivan" <dansulli...@gmail.com>님이
작성:
> HI, All,
>
> I am banging my head against the wall on an issue that I think would
> be pretty simple; I'm trying to determine whether or not the current
> running script has the SetGUID file mode set on it and it is proving
> much more challenging than I had originally anticipated. I am using
> OSX version 10.6 and perl version v5.10.0.
>
> Basically my function looks like this:
>
> use Fcntl;
> sub isCurrentFileSetGID() {
> my $currentFile = $0;
> my $mode = (stat($currentFile))[2];
> print "Mode: " . $mode . "\n";
> my $MyMask = Fcntl::S_ISGID;
> print "MyMask: " . Fcntl::S_ISGID . "\n";
> my $isItSet = $mode & Fcntl::S_ISGID;
> print "iSItSet = " . $isItSet . "\n";
> return $isItSet;
> }
>
> For some reason, the S_ISGID constant is being interpreted as 1024,
> however I am uncertain why. It appears as "0002000" in
> /usr/include/sys/fcntl.h:
>
> #define S_ISGID 0002000 /* [XSI] set group id on execution
> */
>
> When I execute the script, I am getting 1024 as the output for both
> the mask and the operation between the mask and the file mode. Am I
> missing something here? I would expect this to return 1. Can
> somebody help me shed some light on this? The output of my execution
> against a perl script with the setgid bit set is found below.
>
> wireless-s1-so-150-57-199:Perl dsullivan2$ ls -l
> total 8
> -rwx--x--x 1 dsullivan2 staff 731 Oct 29 05:55 pw7.pl
> wireless-s1-so-150-57-199:Perl dsullivan2$ chmod 2711 pw7.pl
> wireless-s1-so-150-57-199:Perl dsullivan2$ ls -l
> total 8
> -rwx--s--x 1 dsullivan2 staff 731 Oct 29 05:55 pw7.pl
> wireless-s1-so-150-57-199:Perl dsullivan2$ ./pw7.pl
> Mode: 34249
> MyMask: 1024
> iSItSet = 1024
> wireless-s1-so-150-57-199:Perl dsullivan2$
>
> Thank-you,
>
> Dan Sullivan
> 312-607-3702
>
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