[pgpool-committers: 7047] pgpool: Fix sefault in pgpool child process in certain case.

[Tatsuo Ishii]

Fix sefault in pgpool child process in certain case.

When all backend go down, pgpool refuses to accept connection from
clients and try to send a message in
validate_backend_connectivity(). For this purpose it connects to the
client and try to read the startup packet. This is done in a PG_TRY
block. The startup packet is read in memory pointed to by "sp", which
is declared as "StartupPacket *volatile". This is fine. But it was
forgotten to initialize the value with NULL. As a result, if reading
startup packet fails, sp would be garbage a pointer and segfaults later
in pool_free_startup_packet(sp).

Fix is, initialize "sp" with NULL.

I have found this accidentally in following way:

1) shutdown all backends.

2) connect to pgpool with invalid client. I have used pcp_attach_node
with pgpool's port number, not pcp's.

Branch
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V4_1_STABLE

Details
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https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=2f141610ba5fe4e2411c43c3f2821f02ba3514d9

Modified Files
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src/protocol/child.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)