From: Tom Lane <tgl@sss.pgh.pa.us>

Making PQrequestCancel safe to call in a signal handler turned out to be
much easier than I feared.  So here are the diffs.

Some notes:
  * I modified the postmaster's packet "iodone" callback interface to allow
    the callback routine to return a continue-or-drop-connection return
    code; this was necessary to allow the connection to be closed after
    receiving a Cancel, rather than proceeding to launch a new backend...
    Being a neatnik, I also made the iodone proc have a typechecked
    parameter list.
  * I deleted all code I could find that had to do with OOB.
  * I made some edits to ensure that all signals mentioned in the code
    are referred to symbolically not by numbers ("SIGUSR2" not "2").
    I think Bruce may have already done at least some of the same edits;
    I hope that merging these patches is not too painful.

3 files changed, 55 insertions, 115 deletions

diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 4aee9b9197a..c1cc08f4c79 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/libpq/auth.c,v 1.28 1998/06/13 04:27:14 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/libpq/auth.c,v 1.29 1998/07/09 03:28:45 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -40,13 +40,13 @@
 #include <libpq/crypt.h>
 
 
-static void sendAuthRequest(Port *port, AuthRequest areq, void (*handler) ());
-static void handle_done_auth(Port *port);
-static void handle_krb4_auth(Port *port);
-static void handle_krb5_auth(Port *port);
-static void handle_password_auth(Port *port);
-static void readPasswordPacket(char *arg, PacketLen len, char *pkt);
-static void pg_passwordv0_recvauth(char *arg, PacketLen len, char *pkt);
+static void sendAuthRequest(Port *port, AuthRequest areq, PacketDoneProc handler);
+static int	handle_done_auth(void *arg, PacketLen len, void *pkt);
+static int	handle_krb4_auth(void *arg, PacketLen len, void *pkt);
+static int	handle_krb5_auth(void *arg, PacketLen len, void *pkt);
+static int	handle_password_auth(void *arg, PacketLen len, void *pkt);
+static int	readPasswordPacket(void *arg, PacketLen len, void *pkt);
+static int	pg_passwordv0_recvauth(void *arg, PacketLen len, void *pkt);
 static int	checkPassword(Port *port, char *user, char *password);
 static int	old_be_recvauth(Port *port);
 static int	map_old_to_new(Port *port, UserAuth old, int status);
@@ -327,8 +327,8 @@ pg_krb5_recvauth(Port *port)
  * Handle a v0 password packet.
  */
 
-static void
-pg_passwordv0_recvauth(char *arg, PacketLen len, char *pkt)
+static int
+pg_passwordv0_recvauth(void *arg, PacketLen len, void *pkt)
 {
 	Port	   *port;
 	PasswordPacketV0 *pp;
@@ -393,6 +393,8 @@ pg_passwordv0_recvauth(char *arg, PacketLen len, char *pkt)
 		if (map_old_to_new(port, uaPassword, status) != STATUS_OK)
 			auth_failed(port);
 	}
+
+	return (STATUS_OK);			/* don't close the connection yet */
 }
 
 
@@ -433,7 +435,7 @@ be_recvauth(Port *port)
 	else
 	{
 		AuthRequest areq;
-		void		(*auth_handler) ();
+		PacketDoneProc auth_handler;
 
 		/* Keep the compiler quiet. */
 
@@ -499,7 +501,7 @@ be_recvauth(Port *port)
  */
 
 static void
-sendAuthRequest(Port *port, AuthRequest areq, void (*handler) ())
+sendAuthRequest(Port *port, AuthRequest areq, PacketDoneProc handler)
 {
 	char	   *dp,
 			   *sp;
@@ -527,7 +529,7 @@ sendAuthRequest(Port *port, AuthRequest areq, void (*handler) ())
 		i += 2;
 	}
 
-	PacketSendSetup(&port->pktInfo, i, handler, (char *) port);
+	PacketSendSetup(&port->pktInfo, i, handler, (void *) port);
 }
 
 
@@ -535,8 +537,8 @@ sendAuthRequest(Port *port, AuthRequest areq, void (*handler) ())
  * Called when we have told the front end that it is authorised.
  */
 
-static void
-handle_done_auth(Port *port)
+static int
+handle_done_auth(void *arg, PacketLen len, void *pkt)
 {
 
 	/*
@@ -544,7 +546,7 @@ handle_done_auth(Port *port)
 	 * start.
 	 */
 
-	return;
+	return STATUS_OK;
 }
 
 
@@ -553,13 +555,17 @@ handle_done_auth(Port *port)
  * authentication.
  */
 
-static void
-handle_krb4_auth(Port *port)
+static int
+handle_krb4_auth(void *arg, PacketLen len, void *pkt)
 {
+	Port	   *port = (Port *) arg;
+
 	if (pg_krb4_recvauth(port) != STATUS_OK)
 		auth_failed(port);
 	else
 		sendAuthRequest(port, AUTH_REQ_OK, handle_done_auth);
+
+	return STATUS_OK;
 }
 
 
@@ -568,13 +574,17 @@ handle_krb4_auth(Port *port)
  * authentication.
  */
 
-static void
-handle_krb5_auth(Port *port)
+static int
+handle_krb5_auth(void *arg, PacketLen len, void *pkt)
 {
+	Port	   *port = (Port *) arg;
+
 	if (pg_krb5_recvauth(port) != STATUS_OK)
 		auth_failed(port);
 	else
 		sendAuthRequest(port, AUTH_REQ_OK, handle_done_auth);
+
+	return STATUS_OK;
 }
 
 
@@ -583,12 +593,16 @@ handle_krb5_auth(Port *port)
  * authentication.
  */
 
-static void
-handle_password_auth(Port *port)
+static int
+handle_password_auth(void *arg, PacketLen len, void *pkt)
 {
+	Port	   *port = (Port *) arg;
+
 	/* Set up the read of the password packet. */
 
-	PacketReceiveSetup(&port->pktInfo, readPasswordPacket, (char *) port);
+	PacketReceiveSetup(&port->pktInfo, readPasswordPacket, (void *) port);
+
+	return STATUS_OK;
 }
 
 
@@ -596,13 +610,11 @@ handle_password_auth(Port *port)
  * Called when we have received the password packet.
  */
 
-static void
-readPasswordPacket(char *arg, PacketLen len, char *pkt)
+static int
+readPasswordPacket(void *arg, PacketLen len, void *pkt)
 {
 	char		password[sizeof(PasswordPacket) + 1];
-	Port	   *port;
-
-	port = (Port *) arg;
+	Port	   *port = (Port *) arg;
 
 	/* Silently truncate a password that is too big. */
 
@@ -615,6 +627,8 @@ readPasswordPacket(char *arg, PacketLen len, char *pkt)
 		auth_failed(port);
 	else
 		sendAuthRequest(port, AUTH_REQ_OK, handle_done_auth);
+
+	return (STATUS_OK);			/* don't close the connection yet */
 }
 
 
@@ -662,7 +676,7 @@ old_be_recvauth(Port *port)
 
 		case STARTUP_PASSWORD_MSG:
 			PacketReceiveSetup(&port->pktInfo, pg_passwordv0_recvauth,
-							   (char *) port);
+							   (void *) port);
 
 			return STATUS_OK;
 
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index a70bbc22e9c..4c5b85b248b 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/libpq/pqcomm.c,v 1.47 1998/06/27 04:53:30 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/libpq/pqcomm.c,v 1.48 1998/07/09 03:28:46 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -30,7 +30,6 @@
  *		pq_getinserv	- initialize address from host and service name
  *		pq_connect		- create remote input / output connection
  *		pq_accept		- accept remote input / output connection
- *		pq_async_notify - receive notification from backend.
  *
  * NOTES
  *		These functions are used by both frontend applications and
@@ -79,7 +78,6 @@
 FILE	   *Pfout,
 		   *Pfin;
 FILE	   *Pfdebug;			/* debugging libpq */
-int			PQAsyncNotifyWaiting;		/* for async. notification */
 
 /* --------------------------------
  *		pq_init - open portal file descriptors
@@ -160,9 +158,7 @@ pq_close()
 		fclose(Pfout);
 		Pfout = NULL;
 	}
-	PQAsyncNotifyWaiting = 0;
 	PQnotifies_init();
-	pq_unregoob();
 }
 
 /* --------------------------------
@@ -418,29 +414,6 @@ pq_putint(int i, int b)
 	}
 }
 
-/* ---
- *	   pq_sendoob - send a string over the out-of-band channel
- *	   pq_recvoob - receive a string over the oob channel
- *	NB: Fortunately, the out-of-band channel doesn't conflict with
- *		buffered I/O because it is separate from regular com. channel.
- * ---
- */
-int
-pq_sendoob(char *msg, int len)
-{
-	int			fd = fileno(Pfout);
-
-	return send(fd, msg, len, MSG_OOB);
-}
-
-int
-pq_recvoob(char *msgPtr, int len)
-{
-	int			fd = fileno(Pfout);
-
-	return recv(fd, msgPtr, len, MSG_OOB);
-}
-
 /* --------------------------------
  *		pq_getinaddr - initialize address from host and port number
  * --------------------------------
@@ -508,55 +481,6 @@ pq_getinserv(struct sockaddr_in * sin, char *host, char *serv)
 }
 
 /*
- * register an out-of-band listener proc--at most one allowed.
- * This is used for receiving async. notification from the backend.
- */
-void
-pq_regoob(void (*fptr) ())
-{
-	int			fd = fileno(Pfout);
-
-#if defined(hpux)
-	ioctl(fd, FIOSSAIOOWN, MyProcPid);
-#elif defined(sco)
-	ioctl(fd, SIOCSPGRP, MyProcPid);
-#else
-	fcntl(fd, F_SETOWN, MyProcPid);
-#endif							/* hpux */
-	pqsignal(SIGURG, fptr);
-}
-
-void
-pq_unregoob()
-{
-	pqsignal(SIGURG, SIG_DFL);
-}
-
-
-void
-pq_async_notify()
-{
-	char		msg[20];
-
-	/* int len = sizeof(msg); */
-	int			len = 20;
-
-	if (pq_recvoob(msg, len) >= 0)
-	{
-		/* debugging */
-		printf("received notification: %s\n", msg);
-		PQAsyncNotifyWaiting = 1;
-		/* PQappendNotify(msg+1); */
-	}
-	else
-	{
-		extern int	errno;
-
-		printf("SIGURG but no data: len = %d, err=%d\n", len, errno);
-	}
-}
-
-/*
  * Streams -- wrapper around Unix socket system calls
  *
  *
@@ -620,7 +544,7 @@ StreamServerPort(char *hostName, short portName, int *fdP)
 		pqdebug("%s", PQerrormsg);
 		return (STATUS_ERROR);
 	}
-	bzero(&saddr, sizeof(saddr));
+	MemSet((char *) &saddr, 0, sizeof(saddr));
 	saddr.sa.sa_family = family;
 	if (family == AF_UNIX)
 	{
diff --git a/src/backend/libpq/pqpacket.c b/src/backend/libpq/pqpacket.c
index 97caae952ac..631af78ce29 100644
--- a/src/backend/libpq/pqpacket.c
+++ b/src/backend/libpq/pqpacket.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/libpq/Attic/pqpacket.c,v 1.15 1998/02/26 04:31:56 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/libpq/Attic/pqpacket.c,v 1.16 1998/07/09 03:28:46 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -33,7 +33,7 @@
  * Set up a packet read for the postmaster event loop.
  */
 
-void		PacketReceiveSetup(Packet *pkt, void (*iodone) (), char *arg)
+void		PacketReceiveSetup(Packet *pkt, PacketDoneProc iodone, void *arg)
 {
 	pkt->nrtodo = sizeof(pkt->len);
 	pkt->ptr = (char *) &pkt->len;
@@ -94,8 +94,8 @@ PacketReceiveFragment(Packet *pkt, int sock)
 			if (pkt->iodone == NULL)
 				return STATUS_ERROR;
 
-			(*pkt->iodone) (pkt->arg, pkt->len - sizeof(pkt->len),
-							(char *) &pkt->pkt);
+			return (*pkt->iodone) (pkt->arg, pkt->len - sizeof(pkt->len),
+								   (void *) &pkt->pkt);
 		}
 
 		return STATUS_OK;
@@ -107,7 +107,7 @@ PacketReceiveFragment(Packet *pkt, int sock)
 	if (errno == EINTR)
 		return STATUS_OK;
 
-	fprintf(stderr, "read() system call failed\n");
+	perror("PacketReceiveFragment: read() failed");
 
 	return STATUS_ERROR;
 }
@@ -117,8 +117,9 @@ PacketReceiveFragment(Packet *pkt, int sock)
  * Set up a packet write for the postmaster event loop.
  */
 
-void		PacketSendSetup(Packet *pkt, int nbytes, void (*iodone) (), char *arg)
+void		PacketSendSetup(Packet *pkt, int nbytes, PacketDoneProc iodone, void *arg)
 {
+	pkt->len = (PacketLen) nbytes;
 	pkt->nrtodo = nbytes;
 	pkt->ptr = (char *) &pkt->pkt;
 	pkt->iodone = iodone;
@@ -153,7 +154,8 @@ PacketSendFragment(Packet *pkt, int sock)
 			if (pkt->iodone == NULL)
 				return STATUS_ERROR;
 
-			(*pkt->iodone) (pkt->arg);
+			return (*pkt->iodone) (pkt->arg, pkt->len,
+								   (void *) &pkt->pkt);
 		}
 
 		return STATUS_OK;
@@ -165,7 +167,7 @@ PacketSendFragment(Packet *pkt, int sock)
 	if (errno == EINTR)
 		return STATUS_OK;
 
-	fprintf(stderr, "write() system call failed\n");
+	perror("PacketSendFragment: write() failed");
 
 	return STATUS_ERROR;
 }