Provide support for multiplexing SIGUSR1 signal. The upcoming synchronous

replication patch needs a signal, but we've already used SIGUSR1 and
SIGUSR2 in normal backends. This patch allows reusing SIGUSR1 for that,
and for other purposes too if the need arises.

1 files changed, 18 insertions, 1 deletions

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 90c4c8400e..0049c86c13 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -2437,6 +2437,23 @@ drop_unnamed_stmt(void)
  */
 
 /*
+ * proc_sigusr1_handler - handle SIGUSR1 signal.
+ *
+ * SIGUSR1 is multiplexed to handle multiple different events. The signalFlags
+ * array in PGPROC indicates which events have been signaled.
+ */
+void
+proc_sigusr1_handler(SIGNAL_ARGS)
+{
+	int			save_errno = errno;
+
+	if (CheckProcSignal(PROCSIG_CATCHUP_INTERRUPT))
+		HandleCatchupInterrupt();
+
+	errno = save_errno;
+}
+
+/*
  * quickdie() occurs when signalled SIGQUIT by the postmaster.
  *
  * Some backend has bought the farm,
@@ -3180,7 +3197,7 @@ PostgresMain(int argc, char *argv[], const char *username)
 	 * of output during who-knows-what operation...
 	 */
 	pqsignal(SIGPIPE, SIG_IGN);
-	pqsignal(SIGUSR1, CatchupInterruptHandler);
+	pqsignal(SIGUSR1, proc_sigusr1_handler);
 	pqsignal(SIGUSR2, NotifyInterruptHandler);
 	pqsignal(SIGFPE, FloatExceptionHandler);