Bug #63908 [Com]: file_put_contents is not atomic.

Edit report at https://bugs.php.net/bug.php?id=63908&edit=1 ID: 63908 Comment by: awm086 at gmail dot com Reported by: awm086 at gmail dot com Summary: file_put_contents is not atomic. Status: Not a bug Type: Bug Package: Filesystem function related Operating System: LINUX PHP Version: Irrelevant Block user comment: N Private report: N New Comment: I noticed that function tempname does the same thing. Is that the case? Previous Comments: ------------------------------------------------------------------------ [2013-01-06 00:33:34] rasmus@php.net http://lxr.php.net/xref/PHP_5_4/ext/standard/file.c#564 ------------------------------------------------------------------------ [2013-01-06 00:24:42] awm086 at gmail dot com Where can I find the C implementation of the function. I am just curious now. ------------------------------------------------------------------------ [2013-01-06 00:09:16] rasmus@php.net Nope, sorry, there isn't. The false indicates that the function wasn't able to complete its operation. Much like the underlying filesystem calls, there is no such thing as transactions or anything along those lines where you can group a bunch of operations into a single atomic unit. That's simply not how filesystem operations work. ------------------------------------------------------------------------ [2013-01-05 23:40:34] awm086 at gmail dot com I cannot belive that a function returns false, indicating that a file failed to be written, and still write to the file system. There must be a way. ------------------------------------------------------------------------ [2013-01-04 23:56:46] rasmus@php.net Sorry, there is no way to guarantee that. Even if we were to check before starting to write, there is no way to do an atomic check+write, so in between checking and writing even though the check said there should be space to write to completion, the filesystem could have filled up by the time we actually do the write. If you need this, you have to do it in userspace and apply whatever logic makes sense for your environment to ensure that the write is safe. ------------------------------------------------------------------------ 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=63908 -- Edit this bug report at https://bugs.php.net/bug.php?id=63908&edit=1