Add -d option to pg_basebackup and pg_receivexlog, for connection string.

Without this, there's no way to pass arbitrary libpq connection parameters
to these applications. It's a bit strange that the option is called
-d/--dbname, when in fact you can *not* pass a database name in it, but it's
consistent with other client applications where a connection string is also
passed using -d.

Original patch by Amit Kapila, heavily modified by me.

doc/src/sgml/ref/pg_basebackup.sgml

@@ -358,6 +358,23 @@ PostgreSQL documentation
     The following command-line options control the database connection parameters.
 
     <variablelist>
+     <varlistentry>
+      <term><option>-d <replaceable class="parameter">connstr</replaceable></option></term>
+      <term><option>--dbname=<replaceable class="parameter">connstr</replaceable></option></term>
+      <listitem>
+       <para>
+        Specifies parameters used to connect to the server, as a connection
+        string. See <xref linkend="libpq-connstring"> for more information.
+       </para>
+       <para>
+        The option is called <literal>--dbname</> for consistency with other
+        client applications, but because <application>pg_basebackup</application>
+        doesn't connect to any particular database in the cluster, database
+        name in the connection string will be ignored.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><option>-h <replaceable class="parameter">host</replaceable></option></term>
       <term><option>--host=<replaceable class="parameter">host</replaceable></option></term>

doc/src/sgml/ref/pg_receivexlog.sgml

@@ -122,6 +122,23 @@ PostgreSQL documentation
     The following command-line options control the database connection parameters.
 
     <variablelist>
+     <varlistentry>
+      <term><option>-d <replaceable class="parameter">connstr</replaceable></option></term>
+      <term><option>--dbname=<replaceable class="parameter">connstr</replaceable></option></term>
+      <listitem>
+       <para>
+        Specifies parameters used to connect to the server, as a connection
+        string. See <xref linkend="libpq-connstring"> for more information.
+       </para>
+       <para>
+        The option is called <literal>--dbname</> for consistency with other
+        client applications, but because <application>pg_basebackup</application>
+        doesn't connect to any particular database in the cluster, database
+        name in the connection string will be ignored.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><option>-h <replaceable class="parameter">host</replaceable></option></term>
       <term><option>--host=<replaceable class="parameter">host</replaceable></option></term>

src/bin/pg_basebackup/pg_basebackup.c

@@ -126,6 +126,7 @@ usage(void)
 	printf(_("  -V, --version          output version information, then exit\n"));
 	printf(_("  -?, --help             show this help, then exit\n"));
 	printf(_("\nConnection options:\n"));
+	printf(_("  -d, --dbname=CONNSTR   connection string\n"));
 	printf(_("  -h, --host=HOSTNAME    database server host or socket directory\n"));
 	printf(_("  -p, --port=PORT        database server port number\n"));
 	printf(_("  -s, --status-interval=INTERVAL\n"
@@ -1540,6 +1541,7 @@ main(int argc, char **argv)
 		{"gzip", no_argument, NULL, 'z'},
 		{"compress", required_argument, NULL, 'Z'},
 		{"label", required_argument, NULL, 'l'},
+		{"dbname", required_argument, NULL, 'd'},
 		{"host", required_argument, NULL, 'h'},
 		{"port", required_argument, NULL, 'p'},
 		{"username", required_argument, NULL, 'U'},
@@ -1572,7 +1574,7 @@ main(int argc, char **argv)
 		}
 	}
 
-	while ((c = getopt_long(argc, argv, "D:F:RxX:l:zZ:c:h:p:U:s:wWvP",
+	while ((c = getopt_long(argc, argv, "D:F:RxX:l:zZ:d:c:h:p:U:s:wWvP",
 							long_options, &option_index)) != -1)
 	{
 		switch (c)
@@ -1663,6 +1665,9 @@ main(int argc, char **argv)
 					exit(1);
 				}
 				break;
+			case 'd':
+				connection_string = pg_strdup(optarg);
+				break;
 			case 'h':
 				dbhost = pg_strdup(optarg);
 				break;

src/bin/pg_basebackup/pg_receivexlog.c

@@ -58,6 +58,7 @@ usage(void)
 	printf(_("  -V, --version          output version information, then exit\n"));
 	printf(_("  -?, --help             show this help, then exit\n"));
 	printf(_("\nConnection options:\n"));
+	printf(_("  -d, --dbname=CONNSTR   connection string\n"));
 	printf(_("  -h, --host=HOSTNAME    database server host or socket directory\n"));
 	printf(_("  -p, --port=PORT        database server port number\n"));
 	printf(_("  -s, --status-interval=INTERVAL\n"
@@ -306,6 +307,7 @@ main(int argc, char **argv)
 		{"help", no_argument, NULL, '?'},
 		{"version", no_argument, NULL, 'V'},
 		{"directory", required_argument, NULL, 'D'},
+		{"dbname", required_argument, NULL, 'd'},
 		{"host", required_argument, NULL, 'h'},
 		{"port", required_argument, NULL, 'p'},
 		{"username", required_argument, NULL, 'U'},
@@ -338,7 +340,7 @@ main(int argc, char **argv)
 		}
 	}
 
-	while ((c = getopt_long(argc, argv, "D:h:p:U:s:nwWv",
+	while ((c = getopt_long(argc, argv, "D:d:h:p:U:s:nwWv",
 							long_options, &option_index)) != -1)
 	{
 		switch (c)
@@ -346,6 +348,9 @@ main(int argc, char **argv)
 			case 'D':
 				basedir = pg_strdup(optarg);
 				break;
+			case 'd':
+				connection_string = pg_strdup(optarg);
+				break;
 			case 'h':
 				dbhost = pg_strdup(optarg);
 				break;

src/bin/pg_basebackup/streamutil.c

@@ -18,6 +18,7 @@
 #include <string.h>
 
 const char *progname;
+char	   *connection_string = NULL;
 char	   *dbhost = NULL;
 char	   *dbuser = NULL;
 char	   *dbport = NULL;
@@ -34,31 +35,67 @@ PGconn *
 GetConnection(void)
 {
 	PGconn	   *tmpconn;
-	int			argcount = 4;	/* dbname, replication, fallback_app_name,
-								 * password */
+	int			argcount = 7;	/* dbname, replication, fallback_app_name,
+								 * host, user, port, password */
 	int			i;
 	const char **keywords;
 	const char **values;
 	char	   *password = NULL;
 	const char *tmpparam;
+	PQconninfoOption *conn_opts = NULL;
+	PQconninfoOption *conn_opt;
+	char	   *err_msg = NULL;
 
-	if (dbhost)
-		argcount++;
-	if (dbuser)
-		argcount++;
-	if (dbport)
+	/*
+	 * Merge the connection info inputs given in form of connection string,
+	 * options and default values (dbname=replication, replication=true,
+	 * etc.)
+	 */
+	i = 0;
+	if (connection_string)
+	{
+		conn_opts = PQconninfoParse(connection_string, &err_msg);
+		if (conn_opts == NULL)
+		{
+			fprintf(stderr, "%s: %s\n", progname, err_msg);
+			return NULL;
+		}
+
+		for (conn_opt = conn_opts; conn_opt->keyword != NULL; conn_opt++)
+		{
+			if (conn_opt->val != NULL && conn_opt->val[0] != '\0')
 				argcount++;
+		}
 
 		keywords = pg_malloc0((argcount + 1) * sizeof(*keywords));
 		values = pg_malloc0((argcount + 1) * sizeof(*values));
 
-	keywords[0] = "dbname";
-	values[0] = "replication";
-	keywords[1] = "replication";
-	values[1] = "true";
-	keywords[2] = "fallback_application_name";
-	values[2] = progname;
-	i = 3;
+		for (conn_opt = conn_opts; conn_opt->keyword != NULL; conn_opt++)
+		{
+			if (conn_opt->val != NULL && conn_opt->val[0] != '\0')
+			{
+				keywords[i] = conn_opt->keyword;
+				values[i] = conn_opt->val;
+				i++;
+			}
+		}
+	}
+	else
+	{
+		keywords = pg_malloc0((argcount + 1) * sizeof(*keywords));
+		values = pg_malloc0((argcount + 1) * sizeof(*values));
+	}
+
+	keywords[i] = "dbname";
+	values[i] = "replication";
+	i++;
+	keywords[i] = "replication";
+	values[i] = "true";
+	i++;
+	keywords[i] = "fallback_application_name";
+	values[i] = progname;
+	i++;
+
 	if (dbhost)
 	{
 		keywords[i] = "host";
@@ -90,15 +127,15 @@ GetConnection(void)
 			 * meaning this is the call for a second session to the same
 			 * database, so just forcibly reuse that password.
 			 */
-			keywords[argcount - 1] = "password";
-			values[argcount - 1] = dbpassword;
+			keywords[i] = "password";
+			values[i] = dbpassword;
 			dbgetpassword = -1; /* Don't try again if this fails */
 		}
 		else if (dbgetpassword == 1)
 		{
 			password = simple_prompt(_("Password: "), 100, false);
-			keywords[argcount - 1] = "password";
-			values[argcount - 1] = password;
+			keywords[i] = "password";
+			values[i] = password;
 		}
 
 		tmpconn = PQconnectdbParams(keywords, values, true);
@@ -130,12 +167,16 @@ GetConnection(void)
 			PQfinish(tmpconn);
 			free(values);
 			free(keywords);
+			if (conn_opts)
+				PQconninfoFree(conn_opts);
 			return NULL;
 		}
 
 		/* Connection ok! */
 		free(values);
 		free(keywords);
+		if (conn_opts)
+			PQconninfoFree(conn_opts);
 
 		/*
 		 * Ensure we have the same value of integer timestamps as the server

src/bin/pg_basebackup/streamutil.h

 #include "libpq-fe.h"
 
 extern const char *progname;
+extern char *connection_string;
 extern char *dbhost;
 extern char *dbuser;
 extern char *dbport;