Change elog(ERROR) to get back to main loop via a plain sigsetjmp,

instead of doing a kill(self, SIGQUIT) and expecting the signal handler
to do it.  Also, clean up inconsistent definitions of the sigjmp buffer
in the several files that already referenced it.

src/backend/bootstrap/bootstrap.c

@@ -7,7 +7,7 @@
  * Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.57 1999/03/25 03:49:25 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/bootstrap/bootstrap.c,v 1.58 1999/04/20 02:19:53 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -184,24 +184,6 @@ static char *values[MAXATTR];	/* cooresponding attribute values */
 int			numattr;			/* number of attributes for cur. rel */
 extern bool	disableFsync;			/* do not fsync the database */
 
-/* The test for HAVE_SIGSETJMP fails on Linux 2.0.x because the test
- *	explicitly disallows sigsetjmp being a #define, which is how it
- *	is declared in Linux. So, to avoid compiler warnings about
- *	sigsetjmp() being redefined, let's not redefine unless necessary.
- * - thomas 1997-12-27
- */
-
-#if !defined(HAVE_SIGSETJMP) && !defined(sigsetjmp)
-static jmp_buf Warn_restart;
-
-#define sigsetjmp(x,y)	setjmp(x)
-#define siglongjmp longjmp
-
-#else
-static sigjmp_buf Warn_restart;
-
-#endif
-
 int			DebugMode;
 static GlobalMemory nogc = (GlobalMemory) NULL; /* special no-gc mem
 												 * context */

src/backend/tcop/postgres.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.106 1999/03/22 16:45:27 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.107 1999/04/20 02:19:53 tgl Exp $
  *
  * NOTES
  *	  this is the "main" module of the postgres backend and
@@ -21,7 +21,6 @@
 #include <string.h>
 #include <signal.h>
 #include <time.h>
-#include <setjmp.h>
 #include <sys/time.h>
 #include <sys/types.h>
 #include <fcntl.h>
@@ -136,15 +135,8 @@ static bool IsEmptyQuery = false;
 
 char		relname[80];		/* current relation name */
 
-#if defined(nextstep)
-jmp_buf		Warn_restart;
-
-#define sigsetjmp(x,y)	setjmp(x)
-#define siglongjmp longjmp
-#else
+/* note: these declarations had better match tcopprot.h */
 DLLIMPORT sigjmp_buf	Warn_restart;
-
-#endif	 /* defined(nextstep) */
 bool		InError;
 
 extern int	NBuffers;
@@ -829,8 +821,15 @@ pg_exec_query_dest(char *query_string,	/* string to execute */
 /* --------------------------------
  *		signal handler routines used in PostgresMain()
  *
- *		handle_warn() is used to catch kill(getpid(),SIGQUIT) which
- *		occurs when elog(ERROR) is called.
+ *		handle_warn() catches SIGQUIT.  It forces control back to the main
+ *		loop, just as if an internal error (elog(ERROR,...)) had occurred.
+ *		elog() used to actually use kill(2) to induce a SIGQUIT to get here!
+ *		But that's not 100% reliable on some systems, so now it does its own
+ *		siglongjmp() instead. 
+ *		We still provide the signal catcher so that an error quit can be
+ *		forced externally.  This should be done only with great caution,
+ *		however, since an asynchronous signal could leave the system in
+ *		who-knows-what inconsistent state.
  *
  *		quickdie() occurs when signalled by the postmaster.
  *		Some backend has bought the farm,
@@ -1531,7 +1530,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
 	if (!IsUnderPostmaster)
 	{
 		puts("\nPOSTGRES backend interactive interface ");
-		puts("$Revision: 1.106 $ $Date: 1999/03/22 16:45:27 $\n");
+		puts("$Revision: 1.107 $ $Date: 1999/04/20 02:19:53 $\n");
 	}
 
 	/* ----------------
@@ -1543,8 +1542,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
 	 *	so that the slaves signal the master to abort the transaction
 	 *	rather than calling AbortCurrentTransaction() themselves.
 	 *
-	 *	Note:  elog(ERROR) causes a kill(getpid(),SIGQUIT) to occur
-	 *		   sending us back here.
+	 *	Note:  elog(ERROR) does a siglongjmp() to transfer control here.
 	 * ----------------
 	 */
 

src/backend/utils/error/elog.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/error/elog.c,v 1.40 1999/04/16 06:38:17 ishii Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/error/elog.c,v 1.41 1999/04/20 02:19:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -32,6 +32,7 @@
 #include "miscadmin.h"
 #include "libpq/libpq.h"
 #include "storage/proc.h"
+#include "tcop/tcopprot.h"
 #include "utils/trace.h"
 
 #ifdef USE_SYSLOG
@@ -216,24 +217,12 @@ elog(int lev, const char *fmt,...)
 
 	if (lev == ERROR)
 	{
-		extern bool InError;
-
 		ProcReleaseSpins(NULL); /* get rid of spinlocks we hold */
 		if (!InError)
 		{
-			if (MyProcPid == 0) {
-				kill(getpid(), SIGQUIT);
-			} else {
-				kill(MyProcPid, SIGQUIT);	/* abort to traffic cop */
-			}
-			pause();
+			/* exit to main loop */
+			siglongjmp(Warn_restart, 1);
 		}
-
-		/*
-		 * The pause(3) is just to avoid race conditions where the thread
-		 * of control on an MP system gets past here (i.e., the signal is
-		 * not received instantaneously).
-		 */
 	}
 
 	if (lev == FATAL)

src/include/tcop/tcopprot.h

@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: tcopprot.h,v 1.17 1999/02/13 23:22:13 momjian Exp $
+ * $Id: tcopprot.h,v 1.18 1999/04/20 02:19:55 tgl Exp $
  *
  * OLD COMMENTS
  *	  This file was created so that other c files could get the two
@@ -18,8 +18,26 @@
 #ifndef TCOPPROT_H
 #define TCOPPROT_H
 
-#include <executor/execdesc.h>
-#include <parser/parse_node.h>
+#include <setjmp.h>
+#include "executor/execdesc.h"
+#include "parser/parse_node.h"
+
+/*  Autoconf's test for HAVE_SIGSETJMP fails on Linux 2.0.x because the test
+ *	explicitly disallows sigsetjmp being a #define, which is how it
+ *	is declared in Linux. So, to avoid compiler warnings about
+ *	sigsetjmp() being redefined, let's not redefine unless necessary.
+ * - thomas 1997-12-27
+ * Autoconf really ought to be brighter about macro-ized system functions...
+ * and this code really ought to be in config.h ...
+ */
+
+#if !defined(HAVE_SIGSETJMP) && !defined(sigsetjmp)
+#define sigjmp_buf jmp_buf
+#define sigsetjmp(x,y)	setjmp(x)
+#define siglongjmp longjmp
+#endif
+extern DLLIMPORT sigjmp_buf	Warn_restart;
+extern bool InError;
 
 #ifndef BOOTSTRAP_INCLUDE
 extern List *pg_parse_and_plan(char *query_string, Oid *typev, int nargs,
@@ -30,7 +48,7 @@ extern void pg_exec_query_acl_override(char *query_string);
 extern void
 			pg_exec_query_dest(char *query_string, CommandDest dest, bool aclOverride);
 
-#endif	 /* BOOTSTRAP_HEADER */
+#endif	 /* BOOTSTRAP_INCLUDE */
 
 extern void handle_warn(SIGNAL_ARGS);
 extern void quickdie(SIGNAL_ARGS);
@@ -42,4 +60,4 @@ extern int PostgresMain(int argc, char *argv[],
 extern void ResetUsage(void);
 extern void ShowUsage(void);
 
-#endif	 /* tcopprotIncluded */
+#endif	 /* TCOPPROT_H */

src/pl/plpgsql/src/pl_exec.c

@@ -3,7 +3,7 @@
  *			  procedural language
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.8 1999/03/22 16:45:30 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.9 1999/04/20 02:19:57 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -55,28 +55,12 @@
 #include "fmgr.h"
 #include "access/heapam.h"
 
+#include "tcop/tcopprot.h"
 #include "utils/syscache.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
 
 
-/************************************************************
- * Make Warn_restart from tcop/postgres.c visible for us.
- * The longjmp() mechanism of the elog(ERROR,...) makes it
- * impossible for us to call exceptions. But at least I
- * would like some suggestions about where in the PL function
- * the error occured.
- *
- * It's ugly - Jan
- ************************************************************/
-#if defined(nextstep)
-#define sigjmp_buf		jmp_buf
-#define sigsetjmp(x,y)	setjmp(x)
-#define siglongjmp		longjmp
-#endif
-
-extern DLLIMPORT sigjmp_buf Warn_restart; /* in tcop/postgres.c */
-
 static PLpgSQL_function *error_info_func = NULL;
 static PLpgSQL_stmt *error_info_stmt = NULL;
 static char *error_info_text = NULL;

src/pl/tcl/pltcl.c

@@ -3,7 +3,7 @@
  *			  procedural language (PL)
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/pl/tcl/pltcl.c,v 1.8 1998/11/27 20:05:27 vadim Exp $
+ *	  $Header: /cvsroot/pgsql/src/pl/tcl/pltcl.c,v 1.9 1999/04/20 02:19:59 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -52,6 +52,7 @@
 #include "fmgr.h"
 #include "access/heapam.h"
 
+#include "tcop/tcopprot.h"
 #include "utils/syscache.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
@@ -90,23 +91,6 @@ typedef struct pltcl_query_desc
 }			pltcl_query_desc;
 
 
-/************************************************************
- * Make Warn_restart from tcop/postgres.c visible for us.
- * The longjmp() mechanism of the elog(ERROR,...) restart let's
- * interpreter levels lay around. So we must tidy up in that
- * case and thus, we have to catch the longjmp's sometimes to
- * return though all the interpreter levels back.
- *
- * It's ugly - Jan
- ************************************************************/
-#if defined(nextstep)
-#define sigjmp_buf	jmp_buf
-#define sigsetjmp(x,y)	setjmp(x)
-#define siglongjmp	longjmp
-#endif
-
-extern sigjmp_buf Warn_restart; /* in tcop/postgres.c */
-
 /**********************************************************************
  * Global data
  **********************************************************************/