pgsql: Prevent shm_mq_send from reading uninitialized memory.

Prevent shm_mq_send from reading uninitialized memory.

shm_mq_send_bytes didn't invariably initialize *bytes_written before
returning, which would cause shm_mq_send to read from uninitialized
memory and add the value it found there to mqh->mqh_partial_bytes.
This could cause the next attempt to send a message via the queue to
fail an assertion (if the queue was detached) or copy data from a
garbage pointer value into the queue (if non-blocking mode was in use).

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/1144ea3421e4bcc24dd7402a1f21ba94638d591b

Modified Files
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src/backend/storage/ipc/shm_mq.c |    7 +++++++
1 file changed, 7 insertions(+)