Crashes on startup and crashes apps when /var/lib/ isn't writable

[Loïc Minier]

Hi there

gallery-app was crashing when run on the read-only images; it was trying to update the "photos taken" metric, but usermetrics daemon was crashing on startup because /var/lib/usermetrics was read-only:
access("/var/lib/usermetrics/usermetrics3.db-journal", F_OK) = -1 ENOENT (No such file or directory)

The gallery-app bt looked like:
#3 0x40cce7ac in __gnu_cxx::__verbose_terminate_handler ()
    at ../../../../src/libstdc++-v3/libsupc++/vterminate.cc:95
#4 0x40ccd1cc in __cxxabiv1::__terminate (handler=<optimized out>)
    at ../../../../src/libstdc++-v3/libsupc++/eh_terminate.cc:38
#5 0x40ccd1e8 in std::terminate ()
    at ../../../../src/libstdc++-v3/libsupc++/eh_terminate.cc:48
#6 0x40ccd412 in __cxxabiv1::__cxa_throw (obj=0x1f3b978,
    tinfo=<optimized out>, dest=<optimized out>)
    at ../../../../src/libstdc++-v3/libsupc++/eh_throw.cc:84
#7 0x4074c74a in UserMetricsInput::MetricManagerImpl::add (this=0x1f44610,
    dataSourceId=..., formatString=..., emptyDataString=..., textDomain=...)
    at /build/buildd/libusermetrics-1.1.1+13.10.20130816/src/libusermetricsinput/MetricManagerImpl.cpp:52
#8 0x0000a69e in CameraApplication::increaseTodaysPhotoMetrics() ()
#9 0x0000ada2 in CameraApplication::qt_metacall(QMetaObject::Call, int, void**) ()
#10 0x4035918a in QMetaObject::metacall(QObject*, QMetaObject::Call, int, void**) () from /usr/lib/arm-linux-gnueabihf/libQt5Core.so.5

It would seem to be a good idea for libusermetrics to be robust in the face of usermetrics daemon crashes and for userdaemon to report a db create failure as such rather than SEGVing :-)

Cheers,