Introduce two new libpq connection functions, PQconnectdbParams and

PQconnectStartParams. These are analogous to PQconnectdb and PQconnectStart
respectively. They differ from the legacy functions in that they accept
two NULL-terminated arrays, keywords and values, rather than conninfo
strings. This avoids the need to build the conninfo string in cases
where it might be inconvenient to do so. Includes documentation.

Also modify psql to utilize PQconnectdbParams rather than PQsetdbLogin.
This allows the new config parameter application_name to be set, which
in turn is displayed in the pg_stat_activity view and included in CSV
log entries. This will also ensure both new functions get regularly
exercised.

Patch by Guillaume Lelarge with review and minor adjustments by
Joe Conway.

4 files changed, 316 insertions, 35 deletions

diff --git a/src/bin/psql/startup.c b/src/bin/psql/startup.c
index 6ffe593786a..b29c84fdaec 100644
--- a/src/bin/psql/startup.c
+++ b/src/bin/psql/startup.c
@@ -3,7 +3,7 @@
  *
  * Copyright (c) 2000-2010, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/bin/psql/startup.c,v 1.158 2010/01/02 16:57:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/bin/psql/startup.c,v 1.159 2010/01/28 06:28:26 joe Exp $
  */
 #include "postgres_fe.h"
 
@@ -90,6 +90,8 @@ main(int argc, char *argv[])
 	char	   *password = NULL;
 	char	   *password_prompt = NULL;
 	bool		new_pass;
+	const char *keywords[] = {"host","port","dbname","user",
+							  "password","application_name",NULL};
 
 	set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("psql"));
 
@@ -171,11 +173,20 @@ main(int argc, char *argv[])
 	/* loop until we have a password if requested by backend */
 	do
 	{
-		new_pass = false;
-		pset.db = PQsetdbLogin(options.host, options.port, NULL, NULL,
-					options.action == ACT_LIST_DB && options.dbname == NULL ?
-							   "postgres" : options.dbname,
-							   options.username, password);
+        const char *values[] = {
+                  options.host,
+                  options.port,
+                  (options.action == ACT_LIST_DB && 
+                               options.dbname == NULL) ? "postgres" : options.dbname,
+                  options.username,
+                  password,
+                  pset.progname,
+                  NULL
+              };
+        
+        new_pass = false;
+
+        pset.db = PQconnectdbParams(keywords, values);
 
 		if (PQstatus(pset.db) == CONNECTION_BAD &&
 			PQconnectionNeedsPassword(pset.db) &&
diff --git a/src/interfaces/libpq/exports.txt b/src/interfaces/libpq/exports.txt
index a7a1b94e111..bdaa5857b7f 100644
--- a/src/interfaces/libpq/exports.txt
+++ b/src/interfaces/libpq/exports.txt
@@ -1,4 +1,4 @@
-# $PostgreSQL: pgsql/src/interfaces/libpq/exports.txt,v 1.24 2010/01/21 14:58:53 rhaas Exp $
+# $PostgreSQL: pgsql/src/interfaces/libpq/exports.txt,v 1.25 2010/01/28 06:28:26 joe Exp $
 # Functions to be exported by libpq DLLs
 PQconnectdb               1
 PQsetdbLogin              2
@@ -155,3 +155,5 @@ PQconninfoParse           152
 PQinitOpenSSL             153
 PQescapeLiteral           154
 PQescapeIdentifier        155
+PQconnectdbParams         156
+PQconnectStartParams      157
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 4d7be078c07..048c438527b 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.384 2010/01/20 21:15:21 petere Exp $
+ *	  $PostgreSQL: pgsql/src/interfaces/libpq/fe-connect.c,v 1.385 2010/01/28 06:28:26 joe Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -262,10 +262,14 @@ static bool connectOptions2(PGconn *conn);
 static int	connectDBStart(PGconn *conn);
 static int	connectDBComplete(PGconn *conn);
 static PGconn *makeEmptyPGconn(void);
+static void fillPGconn(PGconn *conn, PQconninfoOption *connOptions);
 static void freePGconn(PGconn *conn);
 static void closePGconn(PGconn *conn);
 static PQconninfoOption *conninfo_parse(const char *conninfo,
 			   PQExpBuffer errorMessage, bool use_defaults);
+static PQconninfoOption *conninfo_array_parse(const char **keywords,
+				const char **values, PQExpBuffer errorMessage,
+				bool use_defaults);
 static char *conninfo_getval(PQconninfoOption *connOptions,
 				const char *keyword);
 static void defaultNoticeReceiver(void *arg, const PGresult *res);
@@ -290,23 +294,60 @@ pgthreadlock_t pg_g_threadlock = default_threadlock;
 /*
  *		Connecting to a Database
  *
- * There are now four different ways a user of this API can connect to the
+ * There are now six different ways a user of this API can connect to the
  * database.  Two are not recommended for use in new code, because of their
  * lack of extensibility with respect to the passing of options to the
  * backend.  These are PQsetdb and PQsetdbLogin (the former now being a macro
  * to the latter).
  *
  * If it is desired to connect in a synchronous (blocking) manner, use the
- * function PQconnectdb.
+ * function PQconnectdb or PQconnectdbParams. The former accepts a string
+ * of option = value pairs which must be parsed; the latter takes two NULL
+ * terminated arrays instead.
  *
  * To connect in an asynchronous (non-blocking) manner, use the functions
- * PQconnectStart, and PQconnectPoll.
+ * PQconnectStart or PQconnectStartParams (which differ in the same way as 
+ * PQconnectdb and PQconnectdbParams) and PQconnectPoll.
  *
  * Internally, the static functions connectDBStart, connectDBComplete
  * are part of the connection procedure.
  */
 
 /*
+ *		PQconnectdbParams
+ *
+ * establishes a connection to a postgres backend through the postmaster
+ * using connection information in two arrays.
+ *
+ * The keywords array is defined as
+ *
+ *	   const char *params[] = {"option1", "option2", NULL}
+ *
+ * The values array is defined as
+ *
+ *	   const char *values[] = {"value1", "value2", NULL}
+ *
+ * Returns a PGconn* which is needed for all subsequent libpq calls, or NULL
+ * if a memory allocation failed.
+ * If the status field of the connection returned is CONNECTION_BAD,
+ * then some fields may be null'ed out instead of having valid values.
+ *
+ * You should call PQfinish (if conn is not NULL) regardless of whether this
+ * call succeeded.
+ */
+PGconn *
+PQconnectdbParams(const char **keywords, const char **values)
+{
+	PGconn	   *conn = PQconnectStartParams(keywords, values);
+
+	if (conn && conn->status != CONNECTION_BAD)
+		(void) connectDBComplete(conn);
+
+	return conn;
+
+}
+
+/*
  *		PQconnectdb
  *
  * establishes a connection to a postgres backend through the postmaster
@@ -340,12 +381,12 @@ PQconnectdb(const char *conninfo)
 }
 
 /*
- *		PQconnectStart
+ *		PQconnectStartParams
  *
  * Begins the establishment of a connection to a postgres backend through the
- * postmaster using connection information in a string.
+ * postmaster using connection information in a struct.
  *
- * See comment for PQconnectdb for the definition of the string format.
+ * See comment for PQconnectdbParams for the definition of the string format.
  *
  * Returns a PGconn*.  If NULL is returned, a malloc error has occurred, and
  * you should not attempt to proceed with this connection.	If the status
@@ -359,9 +400,10 @@ PQconnectdb(const char *conninfo)
  * See PQconnectPoll for more info.
  */
 PGconn *
-PQconnectStart(const char *conninfo)
+PQconnectStartParams(const char **keywords, const char **values)
 {
-	PGconn	   *conn;
+	PGconn			   *conn;
+	PQconninfoOption   *connOptions;
 
 	/*
 	 * Allocate memory for the conn structure
@@ -371,10 +413,26 @@ PQconnectStart(const char *conninfo)
 		return NULL;
 
 	/*
-	 * Parse the conninfo string
+	 * Parse the conninfo arrays
 	 */
-	if (!connectOptions1(conn, conninfo))
-		return conn;
+	connOptions = conninfo_array_parse(keywords, values,
+									   &conn->errorMessage, true);
+	if (connOptions == NULL)
+	{
+		conn->status = CONNECTION_BAD;
+		/* errorMessage is already set */
+		return false;
+	}
+
+	/*
+	 * Move option values into conn structure
+	 */
+    fillPGconn(conn, connOptions);
+
+	/*
+	 * Free the option info - all is in conn now
+	 */
+	PQconninfoFree(connOptions);
 
 	/*
 	 * Compute derived options
@@ -395,33 +453,65 @@ PQconnectStart(const char *conninfo)
 }
 
 /*
- *		connectOptions1
+ *		PQconnectStart
  *
- * Internal subroutine to set up connection parameters given an already-
- * created PGconn and a conninfo string.  Derived settings should be
- * processed by calling connectOptions2 next.  (We split them because
- * PQsetdbLogin overrides defaults in between.)
+ * Begins the establishment of a connection to a postgres backend through the
+ * postmaster using connection information in a string.
  *
- * Returns true if OK, false if trouble (in which case errorMessage is set
- * and so is conn->status).
+ * See comment for PQconnectdb for the definition of the string format.
+ *
+ * Returns a PGconn*.  If NULL is returned, a malloc error has occurred, and
+ * you should not attempt to proceed with this connection.	If the status
+ * field of the connection returned is CONNECTION_BAD, an error has
+ * occurred. In this case you should call PQfinish on the result, (perhaps
+ * inspecting the error message first).  Other fields of the structure may not
+ * be valid if that occurs.  If the status field is not CONNECTION_BAD, then
+ * this stage has succeeded - call PQconnectPoll, using select(2) to see when
+ * this is necessary.
+ *
+ * See PQconnectPoll for more info.
  */
-static bool
-connectOptions1(PGconn *conn, const char *conninfo)
+PGconn *
+PQconnectStart(const char *conninfo)
 {
-	PQconninfoOption *connOptions;
-	char	   *tmp;
+	PGconn	   *conn;
+
+	/*
+	 * Allocate memory for the conn structure
+	 */
+	conn = makeEmptyPGconn();
+	if (conn == NULL)
+		return NULL;
 
 	/*
 	 * Parse the conninfo string
 	 */
-	connOptions = conninfo_parse(conninfo, &conn->errorMessage, true);
-	if (connOptions == NULL)
+	if (!connectOptions1(conn, conninfo))
+		return conn;
+
+	/*
+	 * Compute derived options
+	 */
+	if (!connectOptions2(conn))
+		return conn;
+
+	/*
+	 * Connect to the database
+	 */
+	if (!connectDBStart(conn))
 	{
+		/* Just in case we failed to set it in connectDBStart */
 		conn->status = CONNECTION_BAD;
-		/* errorMessage is already set */
-		return false;
 	}
 
+	return conn;
+}
+
+static void
+fillPGconn(PGconn *conn, PQconninfoOption *connOptions)
+{
+	char	   *tmp;
+
 	/*
 	 * Move option values into conn structure
 	 *
@@ -482,6 +572,39 @@ connectOptions1(PGconn *conn, const char *conninfo)
 #endif
 	tmp = conninfo_getval(connOptions, "replication");
 	conn->replication = tmp ? strdup(tmp) : NULL;
+}
+
+/*
+ *		connectOptions1
+ *
+ * Internal subroutine to set up connection parameters given an already-
+ * created PGconn and a conninfo string.  Derived settings should be
+ * processed by calling connectOptions2 next.  (We split them because
+ * PQsetdbLogin overrides defaults in between.)
+ *
+ * Returns true if OK, false if trouble (in which case errorMessage is set
+ * and so is conn->status).
+ */
+static bool
+connectOptions1(PGconn *conn, const char *conninfo)
+{
+	PQconninfoOption *connOptions;
+
+	/*
+	 * Parse the conninfo string
+	 */
+	connOptions = conninfo_parse(conninfo, &conn->errorMessage, true);
+	if (connOptions == NULL)
+	{
+		conn->status = CONNECTION_BAD;
+		/* errorMessage is already set */
+		return false;
+	}
+
+	/*
+	 * Move option values into conn structure
+	 */
+    fillPGconn(conn, connOptions);
 
 	/*
 	 * Free the option info - all is in conn now
@@ -3598,6 +3721,149 @@ conninfo_parse(const char *conninfo, PQExpBuffer errorMessage,
 	return options;
 }
 
+/*
+ * Conninfo array parser routine
+ *
+ * If successful, a malloc'd PQconninfoOption array is returned.
+ * If not successful, NULL is returned and an error message is
+ * left in errorMessage.
+ * Defaults are supplied (from a service file, environment variables, etc)
+ * for unspecified options, but only if use_defaults is TRUE.
+ */
+static PQconninfoOption *
+conninfo_array_parse(const char **keywords, const char **values,
+					 PQExpBuffer errorMessage, bool use_defaults)
+{
+	char			   *tmp;
+	PQconninfoOption   *options;
+	PQconninfoOption   *option;
+	int					i = 0;
+
+	/* Make a working copy of PQconninfoOptions */
+	options = malloc(sizeof(PQconninfoOptions));
+	if (options == NULL)
+	{
+		printfPQExpBuffer(errorMessage,
+						  libpq_gettext("out of memory\n"));
+		return NULL;
+	}
+	memcpy(options, PQconninfoOptions, sizeof(PQconninfoOptions));
+
+	/* Parse the keywords/values arrays */
+	while(keywords[i])
+	{
+		const char *pname = keywords[i];
+		const char *pvalue  = values[i];
+
+		if (pvalue != NULL)
+		{
+			/* Search for the param record */
+			for (option = options; option->keyword != NULL; option++)
+			{
+				if (strcmp(option->keyword, pname) == 0)
+					break;
+			}
+
+			/* Check for invalid connection option */
+			if (option->keyword == NULL)
+			{
+				printfPQExpBuffer(errorMessage,
+							 libpq_gettext("invalid connection option \"%s\"\n"),
+								  pname);
+				PQconninfoFree(options);
+				return NULL;
+			}
+
+		    /*
+		     * Store the value
+		     */
+		    if (option->val)
+		    	free(option->val);
+		    option->val = strdup(pvalue);
+		    if (!option->val)
+		    {
+		    	printfPQExpBuffer(errorMessage,
+		    					  libpq_gettext("out of memory\n"));
+		    	PQconninfoFree(options);
+		    	return NULL;
+		    }
+		}
+		++i;
+	}
+
+	/*
+	 * Stop here if caller doesn't want defaults filled in.
+	 */
+	if (!use_defaults)
+		return options;
+
+	/*
+	 * If there's a service spec, use it to obtain any not-explicitly-given
+	 * parameters.
+	 */
+	if (parseServiceInfo(options, errorMessage))
+	{
+		PQconninfoFree(options);
+		return NULL;
+	}
+
+	/*
+	 * Get the fallback resources for parameters not specified in the conninfo
+	 * string nor the service.
+	 */
+	for (option = options; option->keyword != NULL; option++)
+	{
+		if (option->val != NULL)
+			continue;			/* Value was in conninfo or service */
+
+		/*
+		 * Try to get the environment variable fallback
+		 */
+		if (option->envvar != NULL)
+		{
+			if ((tmp = getenv(option->envvar)) != NULL)
+			{
+				option->val = strdup(tmp);
+				if (!option->val)
+				{
+					printfPQExpBuffer(errorMessage,
+									  libpq_gettext("out of memory\n"));
+					PQconninfoFree(options);
+					return NULL;
+				}
+				continue;
+			}
+		}
+
+		/*
+		 * No environment variable specified or this one isn't set - try
+		 * compiled in
+		 */
+		if (option->compiled != NULL)
+		{
+			option->val = strdup(option->compiled);
+			if (!option->val)
+			{
+				printfPQExpBuffer(errorMessage,
+								  libpq_gettext("out of memory\n"));
+				PQconninfoFree(options);
+				return NULL;
+			}
+			continue;
+		}
+
+		/*
+		 * Special handling for user
+		 */
+		if (strcmp(option->keyword, "user") == 0)
+		{
+			option->val = pg_fe_getauthname(errorMessage);
+			continue;
+		}
+	}
+
+	return options;
+}
 
 static char *
 conninfo_getval(PQconninfoOption *connOptions,
diff --git a/src/interfaces/libpq/libpq-fe.h b/src/interfaces/libpq/libpq-fe.h
index 537bd231e8f..5f59da0f753 100644
--- a/src/interfaces/libpq/libpq-fe.h
+++ b/src/interfaces/libpq/libpq-fe.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-fe.h,v 1.149 2010/01/21 14:58:53 rhaas Exp $
+ * $PostgreSQL: pgsql/src/interfaces/libpq/libpq-fe.h,v 1.150 2010/01/28 06:28:26 joe Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -226,10 +226,12 @@ typedef struct pgresAttDesc
 /* make a new client connection to the backend */
 /* Asynchronous (non-blocking) */
 extern PGconn *PQconnectStart(const char *conninfo);
+extern PGconn *PQconnectStartParams(const char **keywords, const char **values);
 extern PostgresPollingStatusType PQconnectPoll(PGconn *conn);
 
 /* Synchronous (blocking) */
 extern PGconn *PQconnectdb(const char *conninfo);
+extern PGconn *PQconnectdbParams(const char **keywords, const char **values);
 extern PGconn *PQsetdbLogin(const char *pghost, const char *pgport,
 			 const char *pgoptions, const char *pgtty,
 			 const char *dbName,