Finding out if a directory is empty ...

[Richard Sharpe]

At 02:36 PM 3/27/01 +0900, Kenichi Okuyama wrote:
>Dear Sharpe,
>
>>>>>> "RS" == Richard Sharpe <sharpe at ns.aus.com> writes:
>RS> 1. Directory is not empty, and you do not have sufficient access to
remove it
>RS> 2. Directory is not empty, and you do have sufficient access to remove it
>RS> 3. Directory is empty, and you do not have sufficient access to remove it
>RS> 4. Directory is empty, and you do have sufficient access to remove it.
>
>RS> I have to return the following:
>
>RS> 1. ENOTEMPTY
>RS> 2. ENOTEMPTY
>RS> 3. EACCES
>RS> 4. 0
>
>RS> As you say, if I try to delete the directory, and it is not empty, I get
>RS> back EACCES from a Samba mapping function, but I then have to
determine if
>RS> the problem was an empty directory to which the caller truly does not
have
>RS> access or the directory is not empty.
>
>Wait, I think you have more possibilities.

Yes, you are correct, now that I think of it ...

>RS> 1. Directory is not empty, and you do not have sufficient access to
remove it
>RS> 2. Directory is not empty, and you do have sufficient access to remove it
>RS> 3. Directory is empty, and you do not have sufficient access to remove it
>RS> 4. Directory is empty, and you do have sufficient access to remove it.
>
>    5. There's no such directory.

Yes. However, SMB servers return a different error than Permission denied.

>    6. System error.

Yes, and I think I return a different error in that case.

>Okey. But! At least, what you should first do is rmdir().

Yes, that is what I do.

>If you succeed, then it's case 4. No doubt.

Yes, that is correct.

>If errno == 'EPERM', then it's write permission that you didn't have.

I never seem to get this back ...

>This is one of the case 3.
>If errno == 'EFAULT' or 'ENOENT' then it's case 5.
>If errno != 'EACCESS' than it's case 6.
>
>Now we get to point where we have to decide whether it's case 1 or
>2.
>But according to whay you've mentioned, we do not really have to
>check if it's case 1 or 2, for ether cases, we're going to return
>"ENOTEMPTY".

Yes, I return ENOTEMPTY if the directory is not empty. But you see, I will
get EACCES back if the directory was not empty, in both cases, and the best
I can do is map it to ENOTEMPTY, as that is the case. I cannot easily
distinguish between cases 1 and 2 above.

># Am I reading your sentence correctly?
>
>
>Just in case you need to find out whether it's case 1 or 2,
>all we need to check is whether we have write permission against
>that directory. To check this you need to call stat(2).
>Still, this is lot lighter than looking inside directory.

Hmmm, maybe I can do that. I will check what the situation is ... I would
have to stat the parent to see what access I have ...

>isn't it?
>---- 
>Kenichi Okuayma at Tokyo Research Lab. IBM-Japan, Co.
>

Regards
-------
Richard Sharpe, sharpe at ns.aus.com
Samba (Team member, www.samba.org), Ethereal (Team member, www.ethereal.com)
Contributing author, SAMS Teach Yourself Samba in 24 Hours
Author, Special Edition, Using Samba