From eb916c305a5cd8683e7e8f955740a7c810220e19 Mon Sep 17 00:00:00 2001 From: Alexey Min Date: Thu, 8 Nov 2018 00:28:30 +0300 Subject: Fix crash if XDG_CACHE_HOME directory is too small or out of space Summary: Incorrect checking for error return code of posix_fallocate() causes function to think that everything is OK, while it is not, causing crash in some cases. BUG: 400610 CCBUG: 339829 Test Plan: good test plan provided in https://bugs.kde.org/show_bug.cgi?id=400610 . Works like a charm, tested in KDE Neon dev-ustable The reason for bug was that return value of posix_fallocate() was assumed to be negative on error, but in fact it is a positive integer. The check was `< 0`, whi should be `!= 0`. ( http://man7.org/linux/man-pages/man3/posix_fallocate.3.html ) With this fix applied test application does not crash, and the output in console widow is: ``` No space left on device. Check filesystem free space at your XDG_CACHE_HOME! The operating system is unable to promise 10547304 bytes for mapped cache, abandoning the cache for crash-safety. org.kde.kcoreaddons: Failed to establish shared memory mapping, will fallback to private memory -- memory usage will increase ``` Reviewers: dfaure, #frameworks, mpyne Reviewed By: dfaure Subscribers: cfeck, kde-frameworks-devel Tags: #frameworks Differential Revision: https://phabricator.kde.org/D16744 --- src/lib/caching/kshareddatacache_p.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/lib/caching/kshareddatacache_p.h b/src/lib/caching/kshareddatacache_p.h index 625bc5d..c13275b 100644 --- a/src/lib/caching/kshareddatacache_p.h +++ b/src/lib/caching/kshareddatacache_p.h @@ -472,7 +472,10 @@ static bool ensureFileAllocated(int fd, size_t fileSize) ; } - if (result < 0) { + if (result != 0) { + if (result == ENOSPC) { + qCritical() << "No space left on device. Check filesystem free space at your XDG_CACHE_HOME!"; + } qCritical() << "The operating system is unable to promise" << fileSize << "bytes for mapped cache, " -- cgit v0.11.2