Make ecpg thread safe.

Lee Kindness

Author: bmomjian

configure.in

@@ -1,5 +1,5 @@
 dnl Process this file with autoconf to produce a configure script.
-dnl $Header: /cvsroot/pgsql/configure.in,v 1.264 2003/06/14 19:21:42 momjian Exp $
+dnl $Header: /cvsroot/pgsql/configure.in,v 1.265 2003/06/15 04:07:58 momjian Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -323,8 +323,8 @@ IFS=$ac_save_IFS
 # Enable libpq to be thread-safe
 #
 AC_MSG_CHECKING([allow threaded libpq])
-PGAC_ARG_BOOL(with, threads, no, [  --with-threads          allow libpq to be thread-safe],
-              [AC_DEFINE([USE_THREADS], 1, [Define to 1 to build libpq with threads. (--with-threads)])])
+PGAC_ARG_BOOL(with, threads, no, [  --with-threads          allow libpq and ecpg to be thread-safe],
+              [AC_DEFINE([USE_THREADS], 1, [Define to 1 to build libpq and ecpg to be thread-safe. (--with-threads)])])
 
 AC_MSG_RESULT([$with_threads])
 AC_SUBST(with_threads)

doc/src/sgml/ecpg.sgml

@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ecpg.sgml,v 1.43 2003/03/25 16:15:35 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ecpg.sgml,v 1.44 2003/06/15 04:07:58 momjian Exp $
 -->
 
 <chapter id="ecpg">
@@ -749,6 +749,13 @@ EXEC SQL INCLUDE <replaceable>filename</replaceable>;
    in the arguments specified for output.
   </para>
 
+  <para>
+   <application>ecpg</application> is thread-safe if it is compiled using
+   the <literal>--with-threads</> <filename>configure</filename>
+   command-line option.  (You might need to use other threading
+   command-line options to compile your client code.)
+  </para>
+
   <para>
    The preprocessor program is called <filename>ecpg</filename> and is
    included in a normal <productname>PostgreSQL</> installation.

doc/src/sgml/installation.sgml

@@ -1,4 +1,4 @@
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/installation.sgml,v 1.134 2003/06/13 23:10:07 momjian Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/installation.sgml,v 1.135 2003/06/15 04:07:58 momjian Exp $ -->
 
 <chapter id="installation">
  <title><![%standalone-include[<productname>PostgreSQL</>]]>
@@ -918,7 +918,8 @@ JAVACMD=$JAVA_HOME/bin/java
        <term><option>--with-threads</option></term>
        <listitem>
         <para>
-	 Allow separate libpq threads to safely control their private connection handles.
+	 Allow separate libpq and ecpg threads to safely control their
+         private connection handles.
         </para>
        </listitem>
       </varlistentry>

src/interfaces/ecpg/ecpglib/Makefile

@@ -4,7 +4,7 @@
 #
 # Copyright (c) 1994, Regents of the University of California
 #
-# $Header: /cvsroot/pgsql/src/interfaces/ecpg/ecpglib/Makefile,v 1.3 2003/05/22 17:20:44 petere Exp $
+# $Header: /cvsroot/pgsql/src/interfaces/ecpg/ecpglib/Makefile,v 1.4 2003/06/15 04:07:58 momjian Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -13,15 +13,15 @@ top_builddir = ../../../..
 include $(top_builddir)/src/Makefile.global
 
 NAME= ecpg
-SO_MAJOR_VERSION= 3
-SO_MINOR_VERSION= 4.2
+SO_MAJOR_VERSION= 4
+SO_MINOR_VERSION= 1.1
 
-override CPPFLAGS := -I$(top_srcdir)/src/interfaces/ecpg/include -I$(libpq_srcdir) $(CPPFLAGS)
+override CPPFLAGS := -I$(top_srcdir)/src/interfaces/ecpg/include -I$(libpq_srcdir) $(CPPFLAGS) $(THREAD_CFLAGS) 
 
 OBJS= execute.o typename.o descriptor.o data.o error.o prepare.o memory.o \
 	connect.o misc.o
 
-SHLIB_LINK = -L../pgtypeslib -lpgtypes $(libpq)
+SHLIB_LINK = -L../pgtypeslib -lpgtypes $(libpq) $(THREAD_LIBS)
 
 all: all-lib
 

src/interfaces/ecpg/ecpglib/connect.c

@@ -1,29 +1,53 @@
-/* $Header: /cvsroot/pgsql/src/interfaces/ecpg/ecpglib/connect.c,v 1.6 2003/06/13 10:50:57 meskes Exp $ */
+/* $Header: /cvsroot/pgsql/src/interfaces/ecpg/ecpglib/connect.c,v 1.7 2003/06/15 04:07:58 momjian Exp $ */
 
+#define POSTGRES_ECPG_INTERNAL
 #include "postgres_fe.h"
 
+#ifdef USE_THREADS
+#include <pthread.h>
+#endif
 #include "ecpgtype.h"
 #include "ecpglib.h"
 #include "ecpgerrno.h"
 #include "extern.h"
 #include "sqlca.h"
 
-static struct connection *all_connections = NULL,
-		   *actual_connection = NULL;
+#ifdef USE_THREADS
+static pthread_mutex_t connections_mutex = PTHREAD_MUTEX_INITIALIZER;
+#endif
+static struct connection *all_connections   = NULL;
+static struct connection *actual_connection = NULL;
 
 struct connection *
 ECPGget_connection(const char *connection_name)
 {
-	struct connection *con = all_connections;
+  struct connection *ret = NULL;
+
+#ifdef USE_THREADS
+  pthread_mutex_lock(&connections_mutex);
+#endif
+
+  if( (connection_name == NULL) || (strcmp(connection_name, "CURRENT") == 0) )
+    {
+      ret = actual_connection;
+    }
+  else
+    {
+      struct connection *con;
+      
+      for( con = all_connections; con != NULL; con = con->next)
+	{
+	  if( strcmp(connection_name, con->name) == 0 )
+	    break;
+	}
+      ret = con;
+    }
 
-	if (connection_name == NULL || strcmp(connection_name, "CURRENT") == 0)
-		return actual_connection;
+#ifdef USE_THREADS
+  pthread_mutex_unlock(&connections_mutex);
+#endif
 
-	for (; con && strcmp(connection_name, con->name) != 0; con = con->next);
-	if (con)
-		return con;
-	else
-		return NULL;
+  return( ret );
 }
 
 static void
@@ -37,6 +61,10 @@ ecpg_finish(struct connection * act)
 		ECPGlog("ecpg_finish: finishing %s.\n", act->name);
 		PQfinish(act->connection);
 
+		/* no need to lock connections_mutex - we're always called
+		   by ECPGdisconnect or ECPGconnect, which are holding
+		   the lock */
+
 		/* remove act from the list */
 		if (act == all_connections)
 			all_connections = act->next;
@@ -118,17 +146,18 @@ ECPGsetconn(int lineno, const char *connection_name)
 static void
 ECPGnoticeProcessor_raise(int code, const char *message)
 {
-	sqlca.sqlcode = code;
-	strncpy(sqlca.sqlerrm.sqlerrmc, message, sizeof(sqlca.sqlerrm.sqlerrmc));
-	sqlca.sqlerrm.sqlerrmc[sizeof(sqlca.sqlerrm.sqlerrmc) - 1] = 0;
-	sqlca.sqlerrm.sqlerrml = strlen(sqlca.sqlerrm.sqlerrmc);
+	struct sqlca_t *sqlca = ECPGget_sqlca();
+	sqlca->sqlcode = code;
+	strncpy(sqlca->sqlerrm.sqlerrmc, message, sizeof(sqlca->sqlerrm.sqlerrmc));
+	sqlca->sqlerrm.sqlerrmc[sizeof(sqlca->sqlerrm.sqlerrmc) - 1] = 0;
+	sqlca->sqlerrm.sqlerrml = strlen(sqlca->sqlerrm.sqlerrmc);
 
 	/* remove trailing newline */
-	if (sqlca.sqlerrm.sqlerrml
-		&& sqlca.sqlerrm.sqlerrmc[sqlca.sqlerrm.sqlerrml - 1] == '\n')
+	if (sqlca->sqlerrm.sqlerrml
+		&& sqlca->sqlerrm.sqlerrmc[sqlca->sqlerrm.sqlerrml - 1] == '\n')
 	{
-		sqlca.sqlerrm.sqlerrmc[sqlca.sqlerrm.sqlerrml - 1] = 0;
-		sqlca.sqlerrm.sqlerrml--;
+		sqlca->sqlerrm.sqlerrmc[sqlca->sqlerrm.sqlerrml - 1] = 0;
+		sqlca->sqlerrm.sqlerrml--;
 	}
 
 	ECPGlog("raising sqlcode %d\n", code);
@@ -141,6 +170,8 @@ ECPGnoticeProcessor_raise(int code, const char *message)
 static void
 ECPGnoticeProcessor(void *arg, const char *message)
 {
+	struct sqlca_t *sqlca = ECPGget_sqlca();
+
 	/* these notices raise an error */
 	if (strncmp(message, "WARNING: ", 9))
 	{
@@ -245,22 +276,23 @@ ECPGnoticeProcessor(void *arg, const char *message)
 	if (strstr(message, "cannot be rolled back"))
 		return;
 
-	/* these and other unmentioned should set sqlca.sqlwarn[2] */
+	/* these and other unmentioned should set sqlca->sqlwarn[2] */
 	/* WARNING: The ':' operator is deprecated.  Use exp(x) instead. */
 	/* WARNING: Rel *: Uninitialized page 0 - fixing */
 	/* WARNING: PortalHeapMemoryFree: * not in alloc set! */
 	/* WARNING: Too old parent tuple found - can't continue vc_repair_frag */
 	/* WARNING: identifier "*" will be truncated to "*" */
 	/* WARNING: InvalidateSharedInvalid: cache state reset */
 	/* WARNING: RegisterSharedInvalid: SI buffer overflow */
-	sqlca.sqlwarn[2] = 'W';
-	sqlca.sqlwarn[0] = 'W';
+	sqlca->sqlwarn[2] = 'W';
+	sqlca->sqlwarn[0] = 'W';
 }
 
 /* this contains some quick hacks, needs to be cleaned up, but it works */
 bool
 ECPGconnect(int lineno, const char *name, const char *user, const char *passwd, const char *connection_name, int autocommit)
 {
+	struct sqlca_t *sqlca = ECPGget_sqlca();
 	struct connection *this;
 	char	   *dbname = strdup(name),
 			   *host = NULL,
@@ -269,7 +301,7 @@ ECPGconnect(int lineno, const char *name, const char *user, const char *passwd,
 			   *realname = NULL,
 			   *options = NULL;
 
-	ECPGinit_sqlca();
+	ECPGinit_sqlca(sqlca);
 
 	if ((this = (struct connection *) ECPGalloc(sizeof(struct connection), lineno)) == NULL)
 		return false;
@@ -394,6 +426,9 @@ ECPGconnect(int lineno, const char *name, const char *user, const char *passwd,
 		realname = strdup(dbname);
 
 	/* add connection to our list */
+#ifdef USE_THREADS
+	pthread_mutex_lock(&connections_mutex);
+#endif
 	if (connection_name != NULL)
 		this->name = ECPGstrdup(connection_name, lineno);
 	else
@@ -424,6 +459,9 @@ ECPGconnect(int lineno, const char *name, const char *user, const char *passwd,
 
         set_backend_err(errmsg, lineno);
 		ecpg_finish(this);
+#ifdef USE_THREADS
+		pthread_mutex_unlock(&connections_mutex);
+#endif
 		ECPGlog("connect: could not open database %s on %s port %s %s%s%s%s in line %d\n\t%s\n",
                 db,
 				host ? host : "<DEFAULT>",
@@ -445,6 +483,9 @@ ECPGconnect(int lineno, const char *name, const char *user, const char *passwd,
 			ECPGfree(dbname);
 		return false;
 	}
+#ifdef USE_THREADS
+	pthread_mutex_unlock(&connections_mutex);
+#endif
 
 	if (host)
 		ECPGfree(host);
@@ -468,11 +509,16 @@ ECPGconnect(int lineno, const char *name, const char *user, const char *passwd,
 bool
 ECPGdisconnect(int lineno, const char *connection_name)
 {
+	struct sqlca_t *sqlca = ECPGget_sqlca();
 	struct connection *con;
 
+#ifdef USE_THREADS
+	pthread_mutex_lock(&connections_mutex);
+#endif
+
 	if (strcmp(connection_name, "ALL") == 0)
 	{
-		ECPGinit_sqlca();
+		ECPGinit_sqlca(sqlca);
 		for (con = all_connections; con;)
 		{
 			struct connection *f = con;
@@ -486,10 +532,19 @@ ECPGdisconnect(int lineno, const char *connection_name)
 		con = ECPGget_connection(connection_name);
 
 		if (!ECPGinit(con, connection_name, lineno))
-			return (false);
+		  {
+#ifdef USE_THREADS
+		    pthread_mutex_unlock(&connections_mutex);
+#endif
+		    return (false);
+		  }
 		else
-			ecpg_finish(con);
+		  ecpg_finish(con);
 	}
 
+#ifdef USE_THREADS
+	pthread_mutex_unlock(&connections_mutex);
+#endif
+
 	return true;
 }

src/interfaces/ecpg/ecpglib/data.c

@@ -1,5 +1,6 @@
-/* $Header: /cvsroot/pgsql/src/interfaces/ecpg/ecpglib/data.c,v 1.4 2003/04/01 14:37:25 meskes Exp $ */
+/* $Header: /cvsroot/pgsql/src/interfaces/ecpg/ecpglib/data.c,v 1.5 2003/06/15 04:07:58 momjian Exp $ */
 
+#define POSTGRES_ECPG_INTERNAL
 #include "postgres_fe.h"
 
 #include <stdlib.h>
@@ -21,6 +22,7 @@ ECPGget_data(const PGresult *results, int act_tuple, int act_field, int lineno,
 			 char *var, char *ind, long varcharsize, long offset,
 			 long ind_offset, bool isarray)
 {
+	struct sqlca_t *sqlca = ECPGget_sqlca();
 	char	   *pval = (char *) PQgetvalue(results, act_tuple, act_field);
 
 	ECPGlog("ECPGget_data line %d: RESULT: %s offset: %ld\n", lineno, pval ? pval : "", offset);
@@ -328,7 +330,7 @@ ECPGget_data(const PGresult *results, int act_tuple, int act_field, int lineno,
 							default:
 								break;
 						}
-						sqlca.sqlwarn[0] = sqlca.sqlwarn[1] = 'W';
+						sqlca->sqlwarn[0] = sqlca->sqlwarn[1] = 'W';
 					}
 				}
 				break;
@@ -373,7 +375,7 @@ ECPGget_data(const PGresult *results, int act_tuple, int act_field, int lineno,
 							default:
 								break;
 						}
-						sqlca.sqlwarn[0] = sqlca.sqlwarn[1] = 'W';
+						sqlca->sqlwarn[0] = sqlca->sqlwarn[1] = 'W';
 
 						variable->len = varcharsize;
 					}