Re: Detecting share violations over cifs with PHP? Feature request

Yes readdir was an example and I am saying error reporting is not very good. I am suggesting ( requesting a feature ) that all I/O functions should return better information so we can detect outcomes of I/O - whichever function is used, whatever file system, whatever circumstance. ----- Original Message ----- From: "Keisial" <keisial@gmail.com> To: "Ian Tighe" <ian.tighe@latitude-51.co.uk> Cc: <internals@lists.php.net> Sent: Thursday, September 17, 2009 1:54 PM Subject: Re: [PHP-DEV] Detecting share violations over cifs with PHP? Feature request

Ian Tighe `wrote:

Hi , I am using readdir with a view to selecting files for opening and reading or just taking a stat of them. I am doing this recursively. I test the output from readdir to see if its a file or dir or link etc and this works well. This suddenly changes though and an item is returned by readdir (that is a filename) but its type cannot be determined - it is not of any type at all! So looking at a wireshark trace revealed there had been a sharing violation but I was blissfully unaware of this. I am seeking to have such an error condition made available so that ANY i/o op can be tested not just for true or false but to further establish the i/o outcome and hence track sharing violations amongst other errors. Apart from the type issue above, my substantive point about readdir was this: If I get a false reply I am not sure if I had a failed i/o operation or I had come to the end of a directory list. As far as I can see ( and I may be wrong of course ) there is for PHP no difference between the two but the impact is significantly different. It was more to demonstrate that error reporting is fairly clumsy in these circumstances.

The readdir() system call doesn't have a better error checking. It will return a null pointer on error, just as on eof. The only way to check if it had an error is by setting errno to 0 before the call and checking its status after it. And the reported shouldn't happen anyway, since they are application errors (passing a bad fd...) not reading problems. Perhaps the sharing violation should be reported by stat() instead of readdir()?

It is certainly true all the files I have seen so far that cause this problem related to either iTunes or Microsoft - especially internet explorer 8 recovery files. It must be they are exclusively locked and any attempt by my software makes to read them brings about a violation which cannot be detected, cannot be recovered from and thus not handled by me. I cannot reliably repeat it as I can barely detect it other than my software will carry on looking for files and directories and not being able to recognise types and actions I wanted are not carried out. I have a wireshark trace of the smb protocol exchanges if that helps but it basically says trans2 query path request, trans2 query path response , create_andx request (which is probably a stat), which is retried several times and finally a create andx response indicating a sharing violation. If I could get hold of that in PHP I could react............. Thanks Ian