f859061eaf
In order to avoid creating libfsdriver exceptions, two changes to VFS are necessary: - the returned position field for reads/writes is no longer abused to return the new pipe size; VFS is perfectly capable of updating the size itself; - during system startup, PFS is now sent a mount request, just like all other file systems. In proper "two steps forward, one step back" fashion, the latter point has the consequence that PFS can no longer drop its privileges at startup. This is probably best resolved with a more general solution for all boot image system services. The upside is that PFS no longer needs to be linked with libc. Change-Id: I92e2410cdb0d93d0e6107bae10bc08efc2dbb8b3