Partially deduplicate interrupt handling for background processes.

Where possible, share signal handler code and main loop interrupt
checking. This saves quite a bit of code and should simplify
maintenance, too.

This commit intends not to change the way anything works, even
though that might allow more code to be unified. It does unify
a bunch of individual variables into a ShutdownRequestPending
flag that has is now used by a bunch of different process types,
though.

Patch by me, reviewed by Andres Freund and Daniel Gustafsson.

Discussion: http://postgr.es/m/CA+TgmoZwDk=BguVDVa+qdA6SBKef=PKbaKDQALTC_9qoz1mJqg@mail.gmail.com

1 files changed, 32 insertions, 0 deletions

diff --git a/src/include/postmaster/interrupt.h b/src/include/postmaster/interrupt.h
new file mode 100644
index 00000000000..8f4e43be200
--- /dev/null
+++ b/src/include/postmaster/interrupt.h
@@ -0,0 +1,32 @@
+/*-------------------------------------------------------------------------
+ *
+ * interrupt.h
+ *	  Interrupt handling routines.
+ *
+ * Responses to interrupts are fairly varied and many types of backends
+ * have their own implementations, but we provide a few generic things
+ * here to facilitate code reuse.
+ *
+ * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/include/postmaster/interrupt.h
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef INTERRUPT_H
+#define INTERRUPT_H
+
+#include <signal.h>
+
+extern PGDLLIMPORT volatile sig_atomic_t ConfigReloadPending;
+extern PGDLLIMPORT volatile sig_atomic_t ShutdownRequestPending;
+
+extern void HandleMainLoopInterrupts(void);
+extern void SignalHandlerForConfigReload(SIGNAL_ARGS);
+extern void SignalHandlerForCrashExit(SIGNAL_ARGS);
+extern void SignalHandlerForShutdownRequest(SIGNAL_ARGS);
+
+#endif