Fix: Argument with 'nonnull' attribute passed null
Reported by scan-build
API Argument with 'nonnull' attribute passed null libringbuffer
/ring_buffer_backend.c 380
API Argument with 'nonnull' attribute passed null libringbuffer
/ring_buffer_backend.c 420
CID 1021259 (#1 of 1): Improper use of negative value
(NEGATIVE_RETURNS)5. negative_returns: sysconf(_SC_PAGESIZE) is passed
to a parameter that cannot be negative.
Fix: close socket on protocol error, sendmsg MSG_NOSIGNAL
Don't try to keep interacting with sessiond when a protocol error is
detected at the UST application side: this means we cannot trust the
protocol anymore, so there is no reason for keeping the socket open.
For instance, if the application is exiting and we receive a new stream,
we're effectively not reading the stream data, and we return an error.
Unfortunately, the session daemon may try to send us another command,
but we will try interpreting the stream data as a command, which is
invalid.
Also, use MSG_NOSIGNAL flag in the fds recvmsg, so the session daemon
don't get killed with SIGPIPE when it cannot send to the socket due to
connection closed.
Listener threads can be cancelled with ust lock held, which can hang the
following ust cleanup routine, because tracepoint probe unregister needs
to take the ust lock.
Fix this by disabling pthread cancellation for the entire duration of
the ust lock.
