Bug 33457

Summary:	tp-qt4 uses non-atomic file write in avatar cache
Product:	Telepathy	Reporter:	Xavier Claessens <xclaesse>
Component:	tp-qt	Assignee:	Telepathy bugs list <telepathy-bugs>
Status:	RESOLVED FIXED	QA Contact:	Telepathy bugs list <telepathy-bugs>
Severity:	normal
Priority:	medium	CC:	ollisal
Version:	unspecified
Hardware:	Other
OS:	All
URL:	http://git.collabora.co.uk/?p=user/xclaesse/telepathy-qt4.git;a=shortlog;h=refs/heads/atomic-write
Whiteboard:
i915 platform:		i915 features:

Description Xavier Claessens 2011-01-25 03:59:23 UTC

The avatar cache is using not-atomic operation to store the image on-disk. This means when an avatar is updated, if more than on process is tracking its avatar data, they will both write the data into the cache at the same time. This is racy.

For now we could just create a QTemporaryFile then rename it. It's probably not 100% portable, but long-term solution is doing the cache in CM as said in bug #33410

Comment 1 Olli Salli 2011-01-25 04:04:23 UTC

Otherwise simple enough, but QFile::rename doesn't overwrite existing files. Looking at how similar tasks are implemented in KDE libraries could be a reasonable step forward.

Comment 2 Xavier Claessens 2011-01-25 04:50:40 UTC

Patch: http://git.collabora.co.uk/?p=user/xclaesse/telepathy-qt4.git;a=shortlog;h=refs/heads/atomic-write

I have to disable autoremove otherwise it remove the renamed file too :(

Comment 3 Xavier Claessens 2011-01-25 06:09:56 UTC

Branch merged.

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