Move pqsignal() to libpgport.

We had two copies of this function in the backend and libpq, which was
already pretty bogus, but it turns out that we need it in some other
programs that don't use libpq (such as pg_test_fsync).  So put it where
it probably should have been all along.  The signal-mask-initialization
support in src/backend/libpq/pqsignal.c stays where it is, though, since
we only need that in the backend.

src/backend/access/transam/xlog.c

@@ -35,7 +35,6 @@
 #include "catalog/catversion.h"
 #include "catalog/pg_control.h"
 #include "catalog/pg_database.h"
-#include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "postmaster/bgwriter.h"

src/backend/libpq/pqsignal.c

@@ -1,8 +1,7 @@
 /*-------------------------------------------------------------------------
  *
  * pqsignal.c
- *	  reliable BSD-style signal(2) routine stolen from RWW who stole it
- *	  from Stevens...
+ *	  Backend signal(2) support (see also src/port/pqsignal.c)
  *
  * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
@@ -11,38 +10,11 @@
  * IDENTIFICATION
  *	  src/backend/libpq/pqsignal.c
  *
- * NOTES
- *		This shouldn't be in libpq, but the monitor and some other
- *		things need it...
- *
- *	A NOTE ABOUT SIGNAL HANDLING ACROSS THE VARIOUS PLATFORMS.
- *
- *	pg_config.h defines the macro HAVE_POSIX_SIGNALS for some platforms and
- *	not for others.  This file and pqsignal.h use that macro to decide
- *	how to handle signalling.
- *
- *	signal(2) handling - this is here because it affects some of
- *	the frontend commands as well as the backend processes.
- *
- *	Ultrix and SunOS provide BSD signal(2) semantics by default.
- *
- *	SVID2 and POSIX signal(2) semantics differ from BSD signal(2)
- *	semantics.	We can use the POSIX sigaction(2) on systems that
- *	allow us to request restartable signals (SA_RESTART).
- *
- *	Some systems don't allow restartable signals at all unless we
- *	link to a special BSD library.
- *
- *	We devoutly hope that there aren't any systems that provide
- *	neither POSIX signals nor BSD signals.	The alternative
- *	is to do signal-handler reinstallation, which doesn't work well
- *	at all.
- * ------------------------------------------------------------------------*/
+ * ------------------------------------------------------------------------
+ */
 
 #include "postgres.h"
 
-#include <signal.h>
-
 #include "libpq/pqsignal.h"
 
 
@@ -145,36 +117,3 @@ pqinitmask(void)
 		sigmask(SIGWINCH) | sigmask(SIGFPE);
 #endif
 }
-
-
-/* Win32 signal handling is in backend/port/win32/signal.c */
-#ifndef WIN32
-
-/*
- * Set up a signal handler
- */
-pqsigfunc
-pqsignal(int signo, pqsigfunc func)
-{
-#if !defined(HAVE_POSIX_SIGNALS)
-	return signal(signo, func);
-#else
-	struct sigaction act,
-				oact;
-
-	act.sa_handler = func;
-	sigemptyset(&act.sa_mask);
-	act.sa_flags = 0;
-	if (signo != SIGALRM)
-		act.sa_flags |= SA_RESTART;
-#ifdef SA_NOCLDSTOP
-	if (signo == SIGCHLD)
-		act.sa_flags |= SA_NOCLDSTOP;
-#endif
-	if (sigaction(signo, &act, &oact) < 0)
-		return SIG_ERR;
-	return oact.sa_handler;
-#endif   /* !HAVE_POSIX_SIGNALS */
-}
-
-#endif   /* WIN32 */

src/backend/main/main.c

@@ -41,9 +41,6 @@
 #include "utils/help_config.h"
 #include "utils/pg_locale.h"
 #include "utils/ps_status.h"
-#ifdef WIN32
-#include "libpq/pqsignal.h"
-#endif
 
 
 const char *progname;

src/backend/port/win32/signal.c

@@ -13,7 +13,7 @@
 
 #include "postgres.h"
 
-#include <libpq/pqsignal.h>
+#include "libpq/pqsignal.h"
 
 /*
  * These are exported for use by the UNBLOCKED_SIGNAL_QUEUE() macro.
@@ -158,7 +158,11 @@ pqsigsetmask(int mask)
 }
 
 
-/* signal manipulation. Only called on main thread, no sync required */
+/*
+ * Unix-like signal handler installation
+ *
+ * Only called on main thread, no sync required
+ */
 pqsigfunc
 pqsignal(int signum, pqsigfunc handler)
 {

src/backend/port/win32/timer.c

@@ -18,8 +18,6 @@
 
 #include "postgres.h"
 
-#include "libpq/pqsignal.h"
-
 
 /* Communication area for inter-thread communication */
 typedef struct timerCA

src/backend/replication/walsender.c

@@ -49,7 +49,6 @@
 #include "funcapi.h"
 #include "libpq/libpq.h"
 #include "libpq/pqformat.h"
-#include "libpq/pqsignal.h"
 #include "miscadmin.h"
 #include "nodes/replnodes.h"
 #include "replication/basebackup.h"

src/backend/utils/misc/timeout.c

@@ -16,7 +16,6 @@
 
 #include <sys/time.h>
 
-#include "libpq/pqsignal.h"
 #include "storage/proc.h"
 #include "utils/timeout.h"
 #include "utils/timestamp.h"