Real Path Name

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

I have the following requirement:

Do some work in any directory the codes are called. However, if the pwd is C:\, don't do the work there.

So, I've come out with the following program:

use Cwd;
if (lc(cwd()) eq 'c:/')
{
   print "I'm not working on this directory!\n";
}
else
{
   print "I'll work on this directory!\n";
}
end;
[download]

However, there's a loophole here. If the user subst's C:\ with Z:\, and calls the codes from Z:\, it'll still run. It is not supposed to run, because Z:\ is effectively C:\.

Is there anyway to work around this subst, or even mapped drives?

Thanks in advance!

Comment on Real Path Name Download Code

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Re: Real Path Name by bellaire (Hermit) on Mar 09, 2009 at 12:58 UTC
It looks like Win32::FileOp exports the method `Substed`, which if invoked on your drive letter will tell you whether it's substed somewhere else, or where the drive mapping leads if it's a network mapped drive. The output syntax is a little odd (in particular it uses windows-native `\` for directory separation rather than perl-standard `/`), but with a little work it should get the job done. Running the following in `-e` from the command line: `print join(',',Substed(split(/\//,cwd)));` [download] ... yields ... `C:\>perl -MCwd -MWin32::FileOp -e "..." ,HarddiskVolume1 X:\>perl -MCwd -MWin32::FileOp -e "..." \??\C:\temp, Z:\>perl -MCwd -MWin32::FileOp -e "..." \??\C:, O:\>perl -MCwd -MWin32::FileOp -e "..." ,LanmanRedirector\;O:000000000002ef75\SOME-MACHINE\Network\Share` [download] Note the comma in the above examples, Substed returns a list of two elements, which I joined with a comma in the output. I've substed `X:` to `C:\temp`, `Z:` to `C:\`, and `O:` is a network share.	[reply] [d/l] [select]
Re^2: Real Path Name by Anonymous Monk on Mar 09, 2009 at 17:48 UTC
Thx a lot, bellaire! It seems that that is what I'm looking for, a way to determine if the cwd is a substituted / mapped, or "real" directory.	[reply]
Re: Real Path Name by jethro (Monsignor) on Mar 09, 2009 at 11:22 UTC
Your script could refuse to work in any directory that has a file 'dontexecutehere.txt' in it. Then you should create that file in C:\, with a small text in it why it was created. I would do this as an additional precaution since there is the danger that someone else might remove the file out of ignorance	[reply]
Re^2: Real Path Name by Anonymous Monk on Mar 09, 2009 at 11:31 UTC
Thx, Jethro. But the do_not_do_any_work directory is actually a regression test depository. I'm hoping that there could be a more foolproof method of handling it. Thx again!	[reply]