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commit    ccbb01ff4a4cac8622930ef6475ed3cf8281e4c7
Author:   Alvaro Herrera <alvherre@alvh.no-ip.org>
Date:     Mon Feb 15 23:33:43 2016 +0000
First released in: 9.6.0, 9.1.21, 9.2.16, 9.3.12, 9.4.7, 9.5.2

    pgbench: avoid FD_ISSET on an invalid file descriptor
    
    The original code wasn't careful to test the file descriptor returned by
    PQsocket() for an invalid socket.  If an invalid socket did turn up,
    that would amount to calling FD_ISSET with fd = -1, whereby undefined
    behavior can be invoked.
    
    To fix, test file descriptor for validity and stop further processing if
    that fails.
    
    Problem noticed by Coverity.
    
    There is an existing FD_ISSET callsite that does check for invalid
    sockets beforehand, but the error message reported by it was
    strerror(errno); in testing the aforementioned change, that turns out to
    result in "bad socket: Success" which isn't terribly helpful.  Instead
    use PQerrorMessage() in both places which is more likely to contain an
    useful error message.
    
    Backpatch-through: 9.1.


 contrib/pgbench/pgbench.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/contrib/pgbench/pgbench.c b/contrib/pgbench/pgbench.c
index 693dbc3934b..6c36ad2528a 100644
--- a/contrib/pgbench/pgbench.c
+++ b/contrib/pgbench/pgbench.c
@@ -3231,7 +3231,7 @@ threadRun(void *arg)
 			sock = PQsocket(st->con);
 			if (sock < 0)
 			{
-				fprintf(stderr, "bad socket: %s\n", strerror(errno));
+				fprintf(stderr, "bad socket: %s", PQerrorMessage(st->con));
 				goto done;
 			}
 
@@ -3299,11 +3299,21 @@ threadRun(void *arg)
 			Command   **commands = sql_files[st->use_file];
 			int			prev_ecnt = st->ecnt;
 
-			if (st->con && (FD_ISSET(PQsocket(st->con), &input_mask)
-							|| commands[st->state]->type == META_COMMAND))
+			if (st->con)
 			{
-				if (!doCustom(thread, st, &result->conn_time, logfile, &aggs))
-					remains--;	/* I've aborted */
+				int			sock = PQsocket(st->con);
+
+				if (sock < 0)
+				{
+					fprintf(stderr, "bad socket: %s", PQerrorMessage(st->con));
+					goto done;
+				}
+				if (FD_ISSET(sock, &input_mask) ||
+					commands[st->state]->type == META_COMMAND)
+				{
+					if (!doCustom(thread, st, &result->conn_time, logfile, &aggs))
+						remains--;	/* I've aborted */
+				}
 			}
 
 			if (st->ecnt > prev_ecnt && commands[st->state]->type == META_COMMAND)


[parent: e3ad502740e8]