Edit report at https://bugs.php.net/bug.php?id=63709&edit=1
ID: 63709 User updated by: eric dot saintetienne at gmail dot com Reported by: eric dot saintetienne at gmail dot com Summary: flock() doesn't trigger mandatory locks on linux Status: Analyzed Type: Bug Package: Filesystem function related Operating System: Linux PHP Version: 5.3.19 Block user comment: N Private report: N New Comment: You're right, dio is a plain inteface to the underlying C function hence exposing real file descriptors (integers). That's also what Python does: it exposes two different types of file objects: standard file objects via the builtin open() and file descriptors via os.open() Is that is feasible with php? Previous Comments: ------------------------------------------------------------------------ [2012-12-07 08:48:41] ahar...@php.net My worry there is that dio resources are (as I recall, anyway) completely distinct from normal file resources, so you couldn't fopen() a file and then dio_fcntl() it: it's all or nothing. ------------------------------------------------------------------------ [2012-12-07 08:42:12] eric dot saintetienne at gmail dot com A fifth option is to pull the "Direct IO" extension into the mainline. http://pecl.php.net/package/dio This extension already expose fcntl() as well as a few other low-level POSIX routines, and have some amount of testing as it's in its fourth version already (though it's said to be in beta state) ------------------------------------------------------------------------ [2012-12-07 03:24:16] larue...@php.net I like 3 :) change the behavior of flock will intruduce a visible bc break ------------------------------------------------------------------------ [2012-12-07 01:48:08] ahar...@php.net The key difference between Python and PHP here is that Python always uses fcntl() internally, whereas PHP will use flock() if it's available (which it obviously is on Linux) and will only fall back to fcntl() if it's not. flock() will never create a mandatory lock, so the manual page is wrong, which I'm pretty sure is my fault. Mea culpa. We can probably fix this by switching to preferring fcntl() within our flock() function as Python does, since that's actually the more useful behaviour, but that would be a (mild) BC break in how flock() behaves in practice â although it would actually bring it into line with what's documented. The options I see are: 1. Change the behaviour of flock() as described above to prefer fcntl(). 2. Add a new lockf() function, as suggested. 3. Just bite the bullet and expose fcntl() as a PHP function on POSIX platforms. 4. Do nothing and update the manual. :) Does anyone have any thoughts? I'm happy to do the donkey work, but am not really sure on the best way to proceed. ------------------------------------------------------------------------ [2012-12-06 14:19:38] eric dot saintetienne at gmail dot com Note that dio_fcntl() of the "Direct IO" extension can successfully exclusively lock the file, but this shouldn't be considered as a workaround as it's not always possible to install extensions. If flock() couldn't be modified for backward compatibility reasons, options could be added to alter its behaviour, or a new call lockf() would be welcome too. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=63709 -- Edit this bug report at https://bugs.php.net/bug.php?id=63709&edit=1
