*** pgsql/src/backend/libpq/pqcomm.c	2010/02/16 19:26:02	1.203
--- pgsql/src/backend/libpq/pqcomm.c	2010/02/18 11:13:45	1.204
***************
*** 30,36 ****
   * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
!  *	$PostgreSQL: pgsql/src/backend/libpq/pqcomm.c,v 1.202 2010/01/15 09:19:02 heikki Exp $
   *
   *-------------------------------------------------------------------------
   */
--- 30,36 ----
   * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
!  *	$PostgreSQL: pgsql/src/backend/libpq/pqcomm.c,v 1.203 2010/02/16 19:26:02 mha Exp $
   *
   *-------------------------------------------------------------------------
   */
*************** pq_peekbyte(void)
*** 821,828 ****
   *		pq_getbyte_if_available	- get a single byte from connection,
   *			if available
   *
!  * The received byte is stored in *c. Returns 1 if a byte was read, 0 if
!  * if no data was available, or EOF.
   * --------------------------------
   */
  int
--- 821,828 ----
   *		pq_getbyte_if_available	- get a single byte from connection,
   *			if available
   *
!  * The received byte is stored in *c. Returns 1 if a byte was read,
!  * 0 if no data was available, or EOF if trouble.
   * --------------------------------
   */
  int
*************** pq_getbyte_if_available(unsigned char *c
*** 848,853 ****
--- 848,880 ----
  	PG_TRY();
  	{
  		r = secure_read(MyProcPort, c, 1);
+ 		if (r < 0)
+ 		{
+ 			/*
+ 			 * Ok if no data available without blocking or interrupted
+ 			 * (though EINTR really shouldn't happen with a non-blocking
+ 			 * socket). Report other errors.
+ 			 */
+ 			if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
+ 				r = 0;
+ 			else
+ 			{
+ 				/*
+ 				 * Careful: an ereport() that tries to write to the client would
+ 				 * cause recursion to here, leading to stack overflow and core
+ 				 * dump!  This message must go *only* to the postmaster log.
+ 				 */
+ 				ereport(COMMERROR,
+ 						(errcode_for_socket_access(),
+ 						 errmsg("could not receive data from client: %m")));
+ 				r = EOF;
+ 			}
+ 		}
+ 		else if (r == 0)
+ 		{
+ 			/* EOF detected */
+ 			r = EOF;
+ 		}
  	}
  	PG_CATCH();
  	{