This addresses a latency issue - chroot_fs_refs called inside pivot_root
in the kernel can take several milliseconds on machines with many threads
running.
This might not always reduce latency for custom forkservers, as additional
fork can be more costly than pivot_root.
PiperOrigin-RevId: 281306284
Change-Id: If503ac76a70e5438e94caf708d79cb0219c66def
Also properly check status of send and use one-byte messages
to avoid issues with partial send, receive.
PiperOrigin-RevId: 258362495
Change-Id: I889b4699c100c80d15b129bf3a254f5442405bc2
PR_SET_PDEATHSIG is already issued for init process in SanitizeCurrentProcess
Same for setsid
PiperOrigin-RevId: 258142844
Change-Id: Iad9e94bd402d576c1b24caab0b03efc50e2df07e
