/src/interfaces/libpq/fe-connect.c

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/*-------------------------------------------------------------------------
 *
 * fe-connect.c
 *	  functions related to setting up a connection to the backend
 *
 * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  src/interfaces/libpq/fe-connect.c
 *
 *-------------------------------------------------------------------------
 */

#include "postgres_fe.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <ctype.h>
#include <time.h>
#include <unistd.h>

#include "libpq-fe.h"
#include "libpq-int.h"
#include "fe-auth.h"
#include "pg_config_paths.h"

#ifdef WIN32
#include "win32.h"
#ifdef _WIN32_IE
#undef _WIN32_IE
#endif
#define _WIN32_IE 0x0500
#ifdef near
#undef near
#endif
#define near
#include <shlobj.h>
#ifdef WIN32_ONLY_COMPILER		/* mstcpip.h is missing on mingw */
#include <mstcpip.h>
#endif
#else
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#ifdef HAVE_NETINET_TCP_H
#include <netinet/tcp.h>
#endif
#include <arpa/inet.h>
#endif

#ifdef ENABLE_THREAD_SAFETY
#ifdef WIN32
#include "pthread-win32.h"
#else
#include <pthread.h>
#endif
#endif

#ifdef USE_LDAP
#ifdef WIN32
#include <winldap.h>
#else
/* OpenLDAP deprecates RFC 1823, but we want standard conformance */
#define LDAP_DEPRECATED 1
#include <ldap.h>
typedef struct timeval LDAP_TIMEVAL;
#endif
static int ldapServiceLookup(const char *purl, PQconninfoOption *options,
				  PQExpBuffer errorMessage);
#endif

#include "libpq/ip.h"
#include "mb/pg_wchar.h"

#ifndef FD_CLOEXEC
#define FD_CLOEXEC 1
#endif


#ifndef WIN32
#define PGPASSFILE ".pgpass"
#else
#define PGPASSFILE "pgpass.conf"
#endif

/*
 * Pre-9.0 servers will return this SQLSTATE if asked to set
 * application_name in a startup packet.  We hard-wire the value rather
 * than looking into errcodes.h since it reflects historical behavior
 * rather than that of the current code.
 */
#define ERRCODE_APPNAME_UNKNOWN "42704"

/* This is part of the protocol so just define it */
#define ERRCODE_INVALID_PASSWORD "28P01"
/* This too */
#define ERRCODE_CANNOT_CONNECT_NOW "57P03"

/*
 * fall back options if they are not specified by arguments or defined
 * by environment variables
 */
#define DefaultHost		"localhost"
#define DefaultTty		""
#define DefaultOption	""
#define DefaultAuthtype		  ""
#define DefaultPassword		  ""
#ifdef USE_SSL
#define DefaultSSLMode "prefer"
#else
#define DefaultSSLMode	"disable"
#endif

/* ----------
 * Definition of the conninfo parameters and their fallback resources.
 *
 * If Environment-Var and Compiled-in are specified as NULL, no
 * fallback is available. If after all no value can be determined
 * for an option, an error is returned.
 *
 * The value for the username is treated specially in conninfo_add_defaults.
 * If the value is not obtained any other way, the username is determined
 * by pg_fe_getauthname().
 *
 * The Label and Disp-Char entries are provided for applications that
 * want to use PQconndefaults() to create a generic database connection
 * dialog. Disp-Char is defined as follows:
 *		""		Normal input field
 *		"*"		Password field - hide value
 *		"D"		Debug option - don't show by default
 *
 * PQconninfoOptions[] is a constant static array that we use to initialize
 * a dynamically allocated working copy.  All the "val" fields in
 * PQconninfoOptions[] *must* be NULL.	In a working copy, non-null "val"
 * fields point to malloc'd strings that should be freed when the working
 * array is freed (see PQconninfoFree).
 *
 * The first part of each struct is identical to the one in libpq-fe.h,
 * which is required since we memcpy() data between the two!
 * ----------
 */
typedef struct _internalPQconninfoOption
{
	char	   *keyword;		/* The keyword of the option			*/
	char	   *envvar;			/* Fallback environment variable name	*/
	char	   *compiled;		/* Fallback compiled in default value	*/
	char	   *val;			/* Option's current value, or NULL		 */
	char	   *label;			/* Label for field in connect dialog	*/
	char	   *dispchar;		/* Indicates how to display this field in a
								 * connect dialog. Values are: "" Display
								 * entered value as is "*" Password field -
								 * hide value "D"  Debug option - don't show
								 * by default */
	int			dispsize;		/* Field size in characters for dialog	*/
	/* ---
	 * Anything above this comment must be synchronized with
	 * PQconninfoOption in libpq-fe.h, since we memcpy() data
	 * between them!
	 * ---
	 */
	off_t		connofs;		/* Offset into PGconn struct, -1 if not there */
} internalPQconninfoOption;

static const internalPQconninfoOption PQconninfoOptions[] = {
	/*
	 * "authtype" is no longer used, so mark it "don't show".  We keep it in
	 * the array so as not to reject conninfo strings from old apps that might
	 * still try to set it.
	 */
	{"authtype", "PGAUTHTYPE", DefaultAuthtype, NULL,
	"Database-Authtype", "D", 20, -1},

	{"service", "PGSERVICE", NULL, NULL,
	"Database-Service", "", 20, -1},

	{"user", "PGUSER", NULL, NULL,
		"Database-User", "", 20,
	offsetof(struct pg_conn, pguser)},

	{"password", "PGPASSWORD", NULL, NULL,
		"Database-Password", "*", 20,
	offsetof(struct pg_conn, pgpass)},

	{"connect_timeout", "PGCONNECT_TIMEOUT", NULL, NULL,
		"Connect-timeout", "", 10,		/* strlen(INT32_MAX) == 10 */
	offsetof(struct pg_conn, connect_timeout)},

	{"dbname", "PGDATABASE", NULL, NULL,
		"Database-Name", "", 20,
	offsetof(struct pg_conn, dbName)},

	{"host", "PGHOST", NULL, NULL,
		"Database-Host", "", 40,
	offsetof(struct pg_conn, pghost)},

	{"hostaddr", "PGHOSTADDR", NULL, NULL,
		"Database-Host-IP-Address", "", 45,
	offsetof(struct pg_conn, pghostaddr)},

	{"port", "PGPORT", DEF_PGPORT_STR, NULL,
		"Database-Port", "", 6,
	offsetof(struct pg_conn, pgport)},

	{"client_encoding", "PGCLIENTENCODING", NULL, NULL,
		"Client-Encoding", "", 10,
	offsetof(struct pg_conn, client_encoding_initial)},

	/*
	 * "tty" is no longer used either, but keep it present for backwards
	 * compatibility.
	 */
	{"tty", "PGTTY", DefaultTty, NULL,
		"Backend-Debug-TTY", "D", 40,
	offsetof(struct pg_conn, pgtty)},

	{"options", "PGOPTIONS", DefaultOption, NULL,
		"Backend-Debug-Options", "D", 40,
	offsetof(struct pg_conn, pgoptions)},

	{"application_name", "PGAPPNAME", NULL, NULL,
		"Application-Name", "", 64,
	offsetof(struct pg_conn, appname)},

	{"fallback_application_name", NULL, NULL, NULL,
		"Fallback-Application-Name", "", 64,
	offsetof(struct pg_conn, fbappname)},

	{"keepalives", NULL, NULL, NULL,
		"TCP-Keepalives", "", 1,	/* should be just '0' or '1' */
	offsetof(struct pg_conn, keepalives)},

	{"keepalives_idle", NULL, NULL, NULL,
		"TCP-Keepalives-Idle", "", 10,	/* strlen(INT32_MAX) == 10 */
	offsetof(struct pg_conn, keepalives_idle)},

	{"keepalives_interval", NULL, NULL, NULL,
		"TCP-Keepalives-Interval", "", 10,		/* strlen(INT32_MAX) == 10 */
	offsetof(struct pg_conn, keepalives_interval)},

	{"keepalives_count", NULL, NULL, NULL,
		"TCP-Keepalives-Count", "", 10, /* strlen(INT32_MAX) == 10 */
	offsetof(struct pg_conn, keepalives_count)},

	/*
	 * ssl options are allowed even without client SSL support because the
	 * client can still handle SSL modes "disable" and "allow". Other
	 * parameters have no effect on non-SSL connections, so there is no reason
	 * to exclude them since none of them are mandatory.
	 */
	{"sslmode", "PGSSLMODE", DefaultSSLMode, NULL,
		"SSL-Mode", "", 12,		/* sizeof("verify-full") == 12 */
	offsetof(struct pg_conn, sslmode)},

	{"sslcompression", "PGSSLCOMPRESSION", "1", NULL,
		"SSL-Compression", "", 1,
	offsetof(struct pg_conn, sslcompression)},

	{"sslcert", "PGSSLCERT", NULL, NULL,
		"SSL-Client-Cert", "", 64,
	offsetof(struct pg_conn, sslcert)},

	{"sslkey", "PGSSLKEY", NULL, NULL,
		"SSL-Client-Key", "", 64,
	offsetof(struct pg_conn, sslkey)},

	{"sslrootcert", "PGSSLROOTCERT", NULL, NULL,
		"SSL-Root-Certificate", "", 64,
	offsetof(struct pg_conn, sslrootcert)},

	{"sslcrl", "PGSSLCRL", NULL, NULL,
		"SSL-Revocation-List", "", 64,
	offsetof(struct pg_conn, sslcrl)},

	{"requirepeer", "PGREQUIREPEER", NULL, NULL,
		"Require-Peer", "", 10,
	offsetof(struct pg_conn, requirepeer)},

#if defined(ENABLE_GSS) || defined(ENABLE_SSPI)
	/* Kerberos and GSSAPI authentication support specifying the service name */
	{"krbsrvname", "PGKRBSRVNAME", PG_KRB_SRVNAM, NULL,
		"Kerberos-service-name", "", 20,
	offsetof(struct pg_conn, krbsrvname)},
#endif

#if defined(ENABLE_GSS) && defined(ENABLE_SSPI)

	/*
	 * GSSAPI and SSPI both enabled, give a way to override which is used by
	 * default
	 */
	{"gsslib", "PGGSSLIB", NULL, NULL,
		"GSS-library", "", 7,	/* sizeof("gssapi") = 7 */
	offsetof(struct pg_conn, gsslib)},
#endif

	{"replication", NULL, NULL, NULL,
		"Replication", "D", 5,
	offsetof(struct pg_conn, replication)},

	/* Terminating entry --- MUST BE LAST */
	{NULL, NULL, NULL, NULL,
	NULL, NULL, 0}
};

static const PQEnvironmentOption EnvironmentOptions[] =
{
	/* common user-interface settings */
	{
		"PGDATESTYLE", "datestyle"
	},
	{
		"PGTZ", "timezone"
	},
	/* internal performance-related settings */
	{
		"PGGEQO", "geqo"
	},
	{
		NULL, NULL
	}
};

/* The connection URI must start with either of the following designators: */
static const char uri_designator[] = "postgresql://";
static const char short_uri_designator[] = "postgres://";

static bool connectOptions1(PGconn *conn, const char *conninfo);
static bool connectOptions2(PGconn *conn);
static int	connectDBStart(PGconn *conn);
static int	connectDBComplete(PGconn *conn);
static PGPing internal_ping(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_init(PQExpBuffer errorMessage);
static PQconninfoOption *parse_connection_string(const char *conninfo,
						PQExpBuffer errorMessage, bool use_defaults);
static int	uri_prefix_length(const char *connstr);
static bool recognized_connection_string(const char *connstr);
static PQconninfoOption *conninfo_parse(const char *conninfo,
			   PQExpBuffer errorMessage, bool use_defaults);
static PQconninfoOption *conninfo_array_parse(const char *const * keywords,
					 const char *const * values, PQExpBuffer errorMessage,
					 bool use_defaults, int expand_dbname);
static bool conninfo_add_defaults(PQconninfoOption *options,
					  PQExpBuffer errorMessage);
static PQconninfoOption *conninfo_uri_parse(const char *uri,
				   PQExpBuffer errorMessage, bool use_defaults);
static bool conninfo_uri_parse_options(PQconninfoOption *options,
						   const char *uri, PQExpBuffer errorMessage);
static bool conninfo_uri_parse_params(char *params,
						  PQconninfoOption *connOptions,
						  PQExpBuffer errorMessage);
static char *conninfo_uri_decode(const char *str, PQExpBuffer errorMessage);
static bool get_hexdigit(char digit, int *value);
static const char *conninfo_getval(PQconninfoOption *connOptions,
				const char *keyword);
static PQconninfoOption *conninfo_storeval(PQconninfoOption *connOptions,
				  const char *keyword, const char *value,
			  PQExpBuffer errorMessage, bool ignoreMissing, bool uri_decode);
static PQconninfoOption *conninfo_find(PQconninfoOption *connOptions,
			  const char *keyword);
static void defaultNoticeReceiver(void *arg, const PGresult *res);
static void defaultNoticeProcessor(void *arg, const char *message);
static int parseServiceInfo(PQconninfoOption *options,
				 PQExpBuffer errorMessage);
static int parseServiceFile(const char *serviceFile,
				 const char *service,
				 PQconninfoOption *options,
				 PQExpBuffer errorMessage,
				 bool *group_found);
static char *pwdfMatchesString(char *buf, char *token);
static char *PasswordFromFile(char *hostname, char *port, char *dbname,
				 char *username);
static bool getPgPassFilename(char *pgpassfile);
static void dot_pg_pass_warning(PGconn *conn);
static void default_threadlock(int acquire);


/* global variable because fe-auth.c needs to access it */
pgthreadlock_t pg_g_threadlock = default_threadlock;


/*
 *		pqDropConnection
 *
 * Close any physical connection to the server, and reset associated
 * state inside the connection object.	We don't release state that
 * would be needed to reconnect, though.
 */
void
pqDropConnection(PGconn *conn)
{
	/* Drop any SSL state */
	pqsecure_close(conn);
	/* Close the socket itself */
	if (conn->sock >= 0)
		closesocket(conn->sock);
	conn->sock = -1;
	/* Discard any unread/unsent data */
	conn->inStart = conn->inCursor = conn->inEnd = 0;
	conn->outCount = 0;
}


/*
 *		Connecting to a Database
 *
 * 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 or PQconnectdbParams. The former accepts a string of
 * option = value pairs (or a URI) which must be parsed; the latter takes two
 * NULL terminated arrays instead.
 *
 * To connect in an asynchronous (non-blocking) manner, use the functions
 * 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 *const * keywords,
				  const char *const * values,
				  int expand_dbname)
{
	PGconn	   *conn = PQconnectStartParams(keywords, values, expand_dbname);

	if (conn && conn->status != CONNECTION_BAD)
		(void) connectDBComplete(conn);

	return conn;

}

/*
 *		PQpingParams
 *
 * check server status, accepting parameters identical to PQconnectdbParams
 */
PGPing
PQpingParams(const char *const * keywords,
			 const char *const * values,
			 int expand_dbname)
{
	PGconn	   *conn = PQconnectStartParams(keywords, values, expand_dbname);
	PGPing		ret;

	ret = internal_ping(conn);
	PQfinish(conn);

	return ret;
}

/*
 *		PQconnectdb
 *
 * establishes a connection to a postgres backend through the postmaster
 * using connection information in a string.
 *
 * The conninfo string is either a whitespace-separated list of
 *
 *	   option = value
 *
 * definitions or a URI (refer to the documentation for details.) Value
 * might be a single value containing no whitespaces or a single quoted
 * string. If a single quote should appear anywhere in the value, it must be
 * escaped with a backslash like \'
 *
 * 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 *
PQconnectdb(const char *conninfo)
{
	PGconn	   *conn = PQconnectStart(conninfo);

	if (conn && conn->status != CONNECTION_BAD)
		(void) connectDBComplete(conn);

	return conn;
}

/*
 *		PQping
 *
 * check server status, accepting parameters identical to PQconnectdb
 */
PGPing
PQping(const char *conninfo)
{
	PGconn	   *conn = PQconnectStart(conninfo);
	PGPing		ret;

	ret = internal_ping(conn);
	PQfinish(conn);

	return ret;
}

/*
 *		PQconnectStartParams
 *
 * Begins the establishment of a connection to a postgres backend through the
 * postmaster using connection information in a struct.
 *
 * 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
 * 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.
 */
PGconn *
PQconnectStartParams(const char *const * keywords,
					 const char *const * values,
					 int expand_dbname)
{
	PGconn	   *conn;
	PQconninfoOption *connOptions;

	/*
	 * Allocate memory for the conn structure
	 */
	conn = makeEmptyPGconn();
	if (conn == NULL)
		return NULL;

	/*
	 * Parse the conninfo arrays
	 */
	connOptions = conninfo_array_parse(keywords, values,
									   &conn->errorMessage,
									   true, expand_dbname);
	if (connOptions == NULL)
	{
		conn->status = CONNECTION_BAD;
		/* errorMessage is already set */
		return conn;
	}

	/*
	 * Move option values into conn structure
	 */
	fillPGconn(conn, connOptions);

	/*
	 * Free the option info - all is in conn now
	 */
	PQconninfoFree(connOptions);

	/*
	 * 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;
	}

	return conn;
}

/*
 *		PQconnectStart
 *
 * Begins the establishment of a connection to a postgres backend through the
 * postmaster using connection information in a string.
 *
 * 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.
 */
PGconn *
PQconnectStart(const char *conninfo)
{
	PGconn	   *conn;

	/*
	 * Allocate memory for the conn structure
	 */
	conn = makeEmptyPGconn();
	if (conn == NULL)
		return NULL;

	/*
	 * Parse the conninfo string
	 */
	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;
	}

	return conn;
}

static void
fillPGconn(PGconn *conn, PQconninfoOption *connOptions)
{
	const internalPQconninfoOption *option;

	/*
	 * Move option values into conn structure
	 *
	 * Don't put anything cute here --- intelligence should be in
	 * connectOptions2 ...
	 *
	 * XXX: probably worth checking strdup() return value here...
	 */
	for (option = PQconninfoOptions; option->keyword; option++)
	{
		const char *tmp = conninfo_getval(connOptions, option->keyword);

		if (tmp && option->connofs >= 0)
		{
			char	  **connmember = (char **) ((char *) conn + option->connofs);

			if (*connmember)
				free(*connmember);
			*connmember = 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 = parse_connection_string(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
	 */
	PQconninfoFree(connOptions);

	return true;
}

/*
 *		connectOptions2
 *
 * Compute derived connection options after absorbing all user-supplied info.
 *
 * Returns true if OK, false if trouble (in which case errorMessage is set
 * and so is conn->status).
 */
static bool
connectOptions2(PGconn *conn)
{
	/*
	 * If database name was not given, default it to equal user name
	 */
	if ((conn->dbName == NULL || conn->dbName[0] == '\0')
		&& conn->pguser != NULL)
	{
		if (conn->dbName)
			free(conn->dbName);
		conn->dbName = strdup(conn->pguser);
	}

	/*
	 * Supply default password if none given
	 */
	if (conn->pgpass == NULL || conn->pgpass[0] == '\0')
	{
		if (conn->pgpass)
			free(conn->pgpass);
		conn->pgpass = PasswordFromFile(conn->pghost, conn->pgport,
										conn->dbName, conn->pguser);
		if (conn->pgpass == NULL)
			conn->pgpass = strdup(DefaultPassword);
		else
			conn->dot_pgpass_used = true;
	}

	/*
	 * Allow unix socket specification in the host name
	 */
	if (conn->pghost && is_absolute_path(conn->pghost))
	{
		if (conn->pgunixsocket)
			free(conn->pgunixsocket);
		conn->pgunixsocket = conn->pghost;
		conn->pghost = NULL;
	}

	/*
	 * validate sslmode option
	 */
	if (conn->sslmode)
	{
		if (strcmp(conn->sslmode, "disable") != 0
			&& strcmp(conn->sslmode, "allow") != 0
			&& strcmp(conn->sslmode, "prefer") != 0
			&& strcmp(conn->sslmode, "require") != 0
			&& strcmp(conn->sslmode, "verify-ca") != 0
			&& strcmp(conn->sslmode, "verify-full") != 0)
		{
			conn->status = CONNECTION_BAD;
			printfPQExpBuffer(&conn->errorMessage,
							libpq_gettext("invalid sslmode value: \"%s\"\n"),
							  conn->sslmode);
			return false;
		}

#ifndef USE_SSL
		switch (conn->sslmode[0])
		{
			case 'a':			/* "allow" */
			case 'p':			/* "prefer" */

				/*
				 * warn user that an SSL connection will never be negotiated
				 * since SSL was not compiled in?
				 */
				break;

			case 'r':			/* "require" */
			case 'v':			/* "verify-ca" or "verify-full" */
				conn->status = CONNECTION_BAD;
				printfPQExpBuffer(&conn->errorMessage,
								  libpq_gettext("sslmode value \"%s\" invalid when SSL support is not compiled in\n"),
								  conn->sslmode);
				return false;
		}
#endif
	}
	else
		conn->sslmode = strdup(DefaultSSLMode);

	/*
	 * Resolve special "auto" client_encoding from the locale
	 */
	if (conn->client_encoding_initial &&
		strcmp(conn->client_encoding_initial, "auto") == 0)
	{
		free(conn->client_encoding_initial);
		conn->client_encoding_initial = strdup(pg_encoding_to_char(pg_get_encoding_from_locale(NULL, true)));
	}

	/*
	 * Only if we get this far is it appropriate to try to connect. (We need a
	 * state flag, rather than just the boolean result of this function, in
	 * case someone tries to PQreset() the PGconn.)
	 */
	conn->options_valid = true;

	return true;
}

/*
 *		PQconndefaults
 *
 * Construct a default connection options array, which identifies all the
 * available options and shows any default values that are available from the
 * environment etc.  On error (eg out of memory), NULL is returned.
 *
 * Using this function, an application may determine all possible options
 * and their current default values.
 *
 * NOTE: as of PostgreSQL 7.0, the returned array is dynamically allocated
 * and should be freed when no longer needed via PQconninfoFree().	(In prior
 * versions, the returned array was static, but that's not thread-safe.)
 * Pre-7.0 applications that use this function will see a small memory leak
 * until they are updated to call PQconninfoFree.
 */
PQconninfoOption *
PQconndefaults(void)
{
	PQExpBufferData errorBuf;
	PQconninfoOption *connOptions;

	/* We don't actually report any errors here, but callees want a buffer */
	initPQExpBuffer(&errorBuf);
	if (PQExpBufferDataBroken(errorBuf))
		return NULL;			/* out of memory already :-( */

	connOptions = conninfo_init(&errorBuf);
	if (connOptions != NULL)
	{
		/* pass NULL errorBuf to ignore errors */
		if (!conninfo_add_defaults(connOptions, NULL))
		{
			PQconninfoFree(connOptions);
			connOptions = NULL;
		}
	}

	termPQExpBuffer(&errorBuf);
	return connOptions;
}

/* ----------------
 *		PQsetdbLogin
 *
 * establishes a connection to a postgres backend through the postmaster
 * at the specified host and port.
 *
 * returns a PGconn* which is needed for all subsequent libpq calls
 *
 * if the status field of the connection returned is CONNECTION_BAD,
 * then only the errorMessage is likely to be useful.
 * ----------------
 */
PGconn *
PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions,
			 const char *pgtty, const char *dbName, const char *login,
			 const char *pwd)
{
	PGconn	   *conn;

	/*
	 * Allocate memory for the conn structure
	 */
	conn = makeEmptyPGconn();
	if (conn == NULL)
		return NULL;

	/*
	 * If the dbName parameter contains what looks like a connection string,
	 * parse it into conn struct using connectOptions1.
	 */
	if (dbName && recognized_connection_string(dbName))
	{
		if (!connectOptions1(conn, dbName))
			return conn;
	}
	else
	{
		/*
		 * Old-style path: first, parse an empty conninfo string in order to
		 * set up the same defaults that PQconnectdb() would use.
		 */
		if (!connectOptions1(conn, ""))
			return conn;

		/* Insert dbName parameter value into struct */
		if (dbName && dbName[0] != '\0')
		{
			if (conn->dbName)
				free(conn->dbName);
			conn->dbName = strdup(dbName);
		}
	}

	/*
	 * Insert remaining parameters into struct, overriding defaults (as well
	 * as any conflicting data from dbName taken as a conninfo).
	 */
	if (pghost && pghost[0] != '\0')
	{
		if (conn->pghost)
			free(conn->pghost);
		conn->pghost = strdup(pghost);
	}

	if (pgport && pgport[0] != '\0')
	{
		if (conn->pgport)
			free(conn->pgport);
		conn->pgport = strdup(pgport);
	}

	if (pgoptions && pgoptions[0] != '\0')
	{
		if (conn->pgoptions)
			free(conn->pgoptions);
		conn->pgoptions = strdup(pgoptions);
	}

	if (pgtty && pgtty[0] != '\0')
	{
		if (conn->pgtty)
			free(conn->pgtty);
		conn->pgtty = strdup(pgtty);
	}

	if (login && login[0] != '\0')
	{
		if (conn->pguser)
			free(conn->pguser);
		conn->pguser = strdup(login);
	}

	if (pwd && pwd[0] != '\0')
	{
		if (conn->pgpass)
			free(conn->pgpass);
		conn->pgpass = strdup(pwd);
	}

	/*
	 * Compute derived options
	 */
	if (!connectOptions2(conn))
		return conn;

	/*
	 * Connect to the database
	 */
	if (connectDBStart(conn))
		(void) connectDBComplete(conn);

	return conn;
}


/* ----------
 * connectNoDelay -
 * Sets the TCP_NODELAY socket option.
 * Returns 1 if successful, 0 if not.
 * ----------
 */
static int
connectNoDelay(PGconn *conn)
{
#ifdef	TCP_NODELAY
	int			on = 1;

	if (setsockopt(conn->sock, IPPROTO_TCP, TCP_NODELAY,
				   (char *) &on,
				   sizeof(on)) < 0)
	{
		char		sebuf[256];

		appendPQExpBuffer(&conn->errorMessage,
			libpq_gettext("could not set socket to TCP no delay mode: %s\n"),
						  SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
		return 0;
	}
#endif

	return 1;
}


/* ----------
 * connectFailureMessage -
 * create a friendly error message on connection failure.
 * ----------
 */
static void
connectFailureMessage(PGconn *conn, int errorno)
{
	char		sebuf[256];

#ifdef HAVE_UNIX_SOCKETS
	if (IS_AF_UNIX(conn->raddr.addr.ss_family))
	{
		char		service[NI_MAXHOST];

		pg_getnameinfo_all(&conn->raddr.addr, conn->raddr.salen,
						   NULL, 0,
						   service, sizeof(service),
						   NI_NUMERICSERV);
		appendPQExpBuffer(&conn->errorMessage,
						  libpq_gettext("could not connect to server: %s\n"
							"\tIs the server running locally and accepting\n"
							"\tconnections on Unix domain socket \"%s\"?\n"),
						  SOCK_STRERROR(errorno, sebuf, sizeof(sebuf)),
						  service);
	}
	else
#endif   /* HAVE_UNIX_SOCKETS */
	{
		char		host_addr[NI_MAXHOST];
		const char *displayed_host;
		struct sockaddr_storage *addr = &conn->raddr.addr;

		/*
		 * Optionally display the network address with the hostname. This is
		 * useful to distinguish between IPv4 and IPv6 connections.
		 */
		if (conn->pghostaddr != NULL)
			strlcpy(host_addr, conn->pghostaddr, NI_MAXHOST);
		else if (addr->ss_family == AF_INET)
		{
			if (inet_net_ntop(AF_INET,
							  &((struct sockaddr_in *) addr)->sin_addr.s_addr,
							  32,
							  host_addr, sizeof(host_addr)) == NULL)
				strcpy(host_addr, "???");
		}
#ifdef HAVE_IPV6
		else if (addr->ss_family == AF_INET6)
		{
			if (inet_net_ntop(AF_INET6,
						  &((struct sockaddr_in6 *) addr)->sin6_addr.s6_addr,
							  128,
							  host_addr, sizeof(host_addr)) == NULL)
				strcpy(host_addr, "???");
		}
#endif
		else
			strcpy(host_addr, "???");

		if (conn->pghostaddr && conn->pghostaddr[0] != '\0')
			displayed_host = conn->pghostaddr;
		else if (conn->pghost && conn->pghost[0] != '\0')
			displayed_host = conn->pghost;
		else
			displayed_host = DefaultHost;

		/*
		 * If the user did not supply an IP address using 'hostaddr', and
		 * 'host' was missing or does not match our lookup, display the
		 * looked-up IP address.
		 */
		if ((conn->pghostaddr == NULL) &&
			(conn->pghost == NULL || strcmp(conn->pghost, host_addr) != 0))
			appendPQExpBuffer(&conn->errorMessage,
							libpq_gettext("could not connect to server: %s\n"
				"\tIs the server running on host \"%s\" (%s) and accepting\n"
									   "\tTCP/IP connections on port %s?\n"),
							  SOCK_STRERROR(errorno, sebuf, sizeof(sebuf)),
							  displayed_host,
							  host_addr,
							  conn->pgport);
		else
			appendPQExpBuffer(&conn->errorMessage,
							libpq_gettext("could not connect to server: %s\n"
					 "\tIs the server running on host \"%s\" and accepting\n"
									   "\tTCP/IP connections on port %s?\n"),
							  SOCK_STRERROR(errorno, sebuf, sizeof(sebuf)),
							  displayed_host,
							  conn->pgport);
	}
}

/*
 * Should we use keepalives?  Returns 1 if yes, 0 if no, and -1 if
 * conn->keepalives is set to a value which is not parseable as an
 * integer.
 */
static int
useKeepalives(PGconn *conn)
{
	char	   *ep;
	int			val;

	if (conn->keepalives == NULL)
		return 1;
	val = strtol(conn->keepalives, &ep, 10);
	if (*ep)
		return -1;
	return val != 0 ? 1 : 0;
}

#ifndef WIN32
/*
 * Set the keepalive idle timer.
 */
static int
setKeepalivesIdle(PGconn *conn)
{
	int			idle;

	if (conn->keepalives_idle == NULL)
		return 1;

	idle = atoi(conn->keepalives_idle);
	if (idle < 0)
		idle = 0;

#ifdef TCP_KEEPIDLE
	if (setsockopt(conn->sock, IPPROTO_TCP, TCP_KEEPIDLE,
				   (char *) &idle, sizeof(idle)) < 0)
	{
		char		sebuf[256];

		appendPQExpBuffer(&conn->errorMessage,
					  libpq_gettext("setsockopt(TCP_KEEPIDLE) failed: %s\n"),
						  SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
		return 0;
	}
#else
#ifdef TCP_KEEPALIVE
	/* Darwin uses TCP_KEEPALIVE rather than TCP_KEEPIDLE */
	if (setsockopt(conn->sock, IPPROTO_TCP, TCP_KEEPALIVE,
				   (char *) &idle, sizeof(idle)) < 0)
	{
		char		sebuf[256];

		appendPQExpBuffer(&conn->errorMessage,
					 libpq_gettext("setsockopt(TCP_KEEPALIVE) failed: %s\n"),
						  SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
		return 0;
	}
#endif
#endif

	return 1;
}

/*
 * Set the keepalive interval.
 */
static int
setKeepalivesInterval(PGconn *conn)
{
	int			interval;

	if (conn->keepalives_interval == NULL)
		return 1;

	interval = atoi(conn->keepalives_interval);
	if (interval < 0)
		interval = 0;

#ifdef TCP_KEEPINTVL
	if (setsockopt(conn->sock, IPPROTO_TCP, TCP_KEEPINTVL,
				   (char *) &interval, sizeof(interval)) < 0)
	{
		char		sebuf[256];

		appendPQExpBuffer(&conn->errorMessage,
					 libpq_gettext("setsockopt(TCP_KEEPINTVL) failed: %s\n"),
						  SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
		return 0;
	}
#endif

	return 1;
}

/*
 * Set the count of lost keepalive packets that will trigger a connection
 * break.
 */
static int
setKeepalivesCount(PGconn *conn)
{
	int			count;

	if (conn->keepalives_count == NULL)
		return 1;

	count = atoi(conn->keepalives_count);
	if (count < 0)
		count = 0;

#ifdef TCP_KEEPCNT
	if (setsockopt(conn->sock, IPPROTO_TCP, TCP_KEEPCNT,
				   (char *) &count, sizeof(count)) < 0)
	{
		char		sebuf[256];

		appendPQExpBuffer(&conn->errorMessage,
					   libpq_gettext("setsockopt(TCP_KEEPCNT) failed: %s\n"),
						  SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
		return 0;
	}
#endif

	return 1;
}
#else							/* Win32 */
#ifdef SIO_KEEPALIVE_VALS
/*
 * Enable keepalives and set the keepalive values on Win32,
 * where they are always set in one batch.
 */
static int
setKeepalivesWin32(PGconn *conn)
{
	struct tcp_keepalive ka;
	DWORD		retsize;
	int			idle = 0;
	int			interval = 0;

	if (conn->keepalives_idle)
		idle = atoi(conn->keepalives_idle);
	if (idle <= 0)
		idle = 2 * 60 * 60;		/* 2 hours = default */

	if (conn->keepalives_interval)
		interval = atoi(conn->keepalives_interval);
	if (interval <= 0)
		interval = 1;			/* 1 second = default */

	ka.onoff = 1;
	ka.keepalivetime = idle * 1000;
	ka.keepaliveinterval = interval * 1000;

	if (WSAIoctl(conn->sock,
				 SIO_KEEPALIVE_VALS,
				 (LPVOID) &ka,
				 sizeof(ka),
				 NULL,
				 0,
				 &retsize,
				 NULL,
				 NULL)
		!= 0)
	{
		appendPQExpBuffer(&conn->errorMessage,
				 libpq_gettext("WSAIoctl(SIO_KEEPALIVE_VALS) failed: %ui\n"),
						  WSAGetLastError());
		return 0;
	}
	return 1;
}
#endif   /* SIO_KEEPALIVE_VALS */
#endif   /* WIN32 */

/* ----------
 * connectDBStart -
 *		Begin the process of making a connection to the backend.
 *
 * Returns 1 if successful, 0 if not.
 * ----------
 */
static int
connectDBStart(PGconn *conn)
{
	int			portnum;
	char		portstr[MAXPGPATH];
	struct addrinfo *addrs = NULL;
	struct addrinfo hint;
	const char *node;
	int			ret;

	if (!conn)
		return 0;

	if (!conn->options_valid)
		goto connect_errReturn;

	/* Ensure our buffers are empty */
	conn->inStart = conn->inCursor = conn->inEnd = 0;
	conn->outCount = 0;

	/*
	 * Determine the parameters to pass to pg_getaddrinfo_all.
	 */

	/* Initialize hint structure */
	MemSet(&hint, 0, sizeof(hint));
	hint.ai_socktype = SOCK_STREAM;
	hint.ai_family = AF_UNSPEC;

	/* Set up port number as a string */
	if (conn->pgport != NULL && conn->pgport[0] != '\0')
	{
		portnum = atoi(conn->pgport);
		if (portnum < 1 || portnum > 65535)
		{
			appendPQExpBuffer(&conn->errorMessage,
							  libpq_gettext("invalid port number: \"%s\"\n"),
							  conn->pgport);
			conn->options_valid = false;
			goto connect_errReturn;
		}
	}
	else
		portnum = DEF_PGPORT;
	snprintf(portstr, sizeof(portstr), "%d", portnum);

	if (conn->pghostaddr != NULL && conn->pghostaddr[0] != '\0')
	{
		/* Using pghostaddr avoids a hostname lookup */
		node = conn->pghostaddr;
		hint.ai_family = AF_UNSPEC;
		hint.ai_flags = AI_NUMERICHOST;
	}
	else if (conn->pghost != NULL && conn->pghost[0] != '\0')
	{
		/* Using pghost, so we have to look-up the hostname */
		node = conn->pghost;
		hint.ai_family = AF_UNSPEC;
	}
	else
	{
#ifdef HAVE_UNIX_SOCKETS
		/* pghostaddr and pghost are NULL, so use Unix domain socket */
		node = NULL;
		hint.ai_family = AF_UNIX;
		UNIXSOCK_PATH(portstr, portnum, conn->pgunixsocket);
		if (strlen(portstr) >= UNIXSOCK_PATH_BUFLEN)
		{
			appendPQExpBuffer(&conn->errorMessage,
							  libpq_gettext("Unix-domain socket path \"%s\" is too long (maximum %d bytes)\n"),
							  portstr,
							  (int) (UNIXSOCK_PATH_BUFLEN - 1));
			conn->options_valid = false;
			goto connect_errReturn;
		}
#else
		/* Without Unix sockets, default to localhost instead */
		node = DefaultHost;
		hint.ai_family = AF_UNSPEC;
#endif   /* HAVE_UNIX_SOCKETS */
	}

	/* Use pg_getaddrinfo_all() to resolve the address */
	ret = pg_getaddrinfo_all(node, portstr, &hint, &addrs);
	if (ret || !addrs)
	{
		if (node)
			appendPQExpBuffer(&conn->errorMessage,
							  libpq_gettext("could not translate host name \"%s\" to address: %s\n"),
							  node, gai_strerror(ret));
		else
			appendPQExpBuffer(&conn->errorMessage,
							  libpq_gettext("could not translate Unix-domain socket path \"%s\" to address: %s\n"),
							  portstr, gai_strerror(ret));
		if (addrs)
			pg_freeaddrinfo_all(hint.ai_family, addrs);
		conn->options_valid = false;
		goto connect_errReturn;
	}

#ifdef USE_SSL
	/* setup values based on SSL mode */
	if (conn->sslmode[0] == 'd')	/* "disable" */
		conn->allow_ssl_try = false;
	else if (conn->sslmode[0] == 'a')	/* "allow" */
		conn->wait_ssl_try = true;
#endif

	/*
	 * Set up to try to connect, with protocol 3.0 as the first attempt.
	 */
	conn->addrlist = addrs;
	conn->addr_cur = addrs;
	conn->addrlist_family = hint.ai_family;
	conn->pversion = PG_PROTOCOL(3, 0);
	conn->send_appname = true;
	conn->status = CONNECTION_NEEDED;

	/*
	 * The code for processing CONNECTION_NEEDED state is in PQconnectPoll(),
	 * so that it can easily be re-executed if needed again during the
	 * asynchronous startup process.  However, we must run it once here,
	 * because callers expect a success return from this routine to mean that
	 * we are in PGRES_POLLING_WRITING connection state.
	 */
	if (PQconnectPoll(conn) == PGRES_POLLING_WRITING)
		return 1;

connect_errReturn:
	pqDropConnection(conn);
	conn->status = CONNECTION_BAD;
	return 0;
}


/*
 *		connectDBComplete
 *
 * Block and complete a connection.
 *
 * Returns 1 on success, 0 on failure.
 */
static int
connectDBComplete(PGconn *conn)
{
	PostgresPollingStatusType flag = PGRES_POLLING_WRITING;
	time_t		finish_time = ((time_t) -1);

	if (conn == NULL || conn->status == CONNECTION_BAD)
		return 0;

	/*
	 * Set up a time limit, if connect_timeout isn't zero.
	 */
	if (conn->connect_timeout != NULL)
	{
		int			timeout = atoi(conn->connect_timeout);

		if (timeout > 0)
		{
			/*
			 * Rounding could cause connection to fail; need at least 2 secs
			 */
			if (timeout < 2)
				timeout = 2;
			/* calculate the finish time based on start + timeout */
			finish_time = time(NULL) + timeout;
		}
	}

	for (;;)
	{
		/*
		 * Wait, if necessary.	Note that the initial state (just after
		 * PQconnectStart) is to wait for the socket to select for writing.
		 */
		switch (flag)
		{
			case PGRES_POLLING_OK:

				/*
				 * Reset stored error messages since we now have a working
				 * connection
				 */
				resetPQExpBuffer(&conn->errorMessage);
				return 1;		/* success! */

			case PGRES_POLLING_READING:
				if (pqWaitTimed(1, 0, conn, finish_time))
				{
					conn->status = CONNECTION_BAD;
					return 0;
				}
				break;

			case PGRES_POLLING_WRITING:
				if (pqWaitTimed(0, 1, conn, finish_time))
				{
					conn->status = CONNECTION_BAD;
					return 0;
				}
				break;

			default:
				/* Just in case we failed to set it in PQconnectPoll */
				conn->status = CONNECTION_BAD;
				return 0;
		}

		/*
		 * Now try to advance the state machine.
		 */
		flag = PQconnectPoll(conn);
	}
}

/* ----------------
 *		PQconnectPoll
 *
 * Poll an asynchronous connection.
 *
 * Returns a PostgresPollingStatusType.
 * Before calling this function, use select(2) to determine when data
 * has arrived..
 *
 * You must call PQfinish whether or not this fails.
 *
 * This function and PQconnectStart are intended to allow connections to be
 * made without blocking the execution of your program on remote I/O. However,
 * there are a number of caveats:
 *
 *	 o	If you call PQtrace, ensure that the stream object into which you trace
 *		will not block.
 *	 o	If you do not supply an IP address for the remote host (i.e. you
 *		supply a host name instead) then PQconnectStart will block on
 *		gethostbyname.	You will be fine if using Unix sockets (i.e. by
 *		supplying neither a host name nor a host address).
 *	 o	If your backend wants to use Kerberos authentication then you must
 *		supply both a host name and a host address, otherwise this function
 *		may block on gethostname.
 *
 * ----------------
 */
PostgresPollingStatusType
PQconnectPoll(PGconn *conn)
{
	PGresult   *res;
	char		sebuf[256];
	int			optval;

	if (conn == NULL)
		return PGRES_POLLING_FAILED;

	/* Get the new data */
	switch (conn->status)
	{
			/*
			 * We really shouldn't have been polled in these two cases, but we
			 * can handle it.
			 */
		case CONNECTION_BAD:
			return PGRES_POLLING_FAILED;
		case CONNECTION_OK:
			return PGRES_POLLING_OK;

			/* These are reading states */
		case CONNECTION_AWAITING_RESPONSE:
		case CONNECTION_AUTH_OK:
			{
				/* Load waiting data */
				int			n = pqReadData(conn);

				if (n < 0)
					goto error_return;
				if (n == 0)
					return PGRES_POLLING_READING;

				break;
			}

			/* These are writing states, so we just proceed. */
		case CONNECTION_STARTED:
		case CONNECTION_MADE:
			break;

			/* We allow pqSetenvPoll to decide whether to proceed. */
		case CONNECTION_SETENV:
			break;

			/* Special cases: proceed without waiting. */
		case CONNECTION_SSL_STARTUP:
		case CONNECTION_NEEDED:
			break;

		default:
			appendPQExpBufferStr(&conn->errorMessage,
								 libpq_gettext(
											   "invalid connection state, "
								 "probably indicative of memory corruption\n"
											));
			goto error_return;
	}


keep_going:						/* We will come back to here until there is
								 * nothing left to do. */
	switch (conn->status)
	{
		case CONNECTION_NEEDED:
			{
				/*
				 * Try to initiate a connection to one of the addresses
				 * returned by pg_getaddrinfo_all().  conn->addr_cur is the
				 * next one to try. We fail when we run out of addresses.
				 */
				while (conn->addr_cur != NULL)
				{
					struct addrinfo *addr_cur = conn->addr_cur;

					/* Remember current address for possible error msg */
					memcpy(&conn->raddr.addr, addr_cur->ai_addr,
						   addr_cur->ai_addrlen);
					conn->raddr.salen = addr_cur->ai_addrlen;

					/* Open a socket */
					conn->sock = socket(addr_cur->ai_family, SOCK_STREAM, 0);
					if (conn->sock < 0)
					{
						/*
						 * ignore socket() failure if we have more addresses
						 * to try
						 */
						if (addr_cur->ai_next != NULL)
						{
							conn->addr_cur = addr_cur->ai_next;
							continue;
						}
						appendPQExpBuffer(&conn->errorMessage,
							  libpq_gettext("could not create socket: %s\n"),
							SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
						break;
					}

					/*
					 * Select socket options: no delay of outgoing data for
					 * TCP sockets, nonblock mode, close-on-exec. Fail if any
					 * of this fails.
					 */
					if (!IS_AF_UNIX(addr_cur->ai_family))
					{
						if (!connectNoDelay(conn))
						{
							pqDropConnection(conn);
							conn->addr_cur = addr_cur->ai_next;
							continue;
						}
					}
					if (!pg_set_noblock(conn->sock))
					{
						appendPQExpBuffer(&conn->errorMessage,
										  libpq_gettext("could not set socket to nonblocking mode: %s\n"),
							SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
						pqDropConnection(conn);
						conn->addr_cur = addr_cur->ai_next;
						continue;
					}

#ifdef F_SETFD
					if (fcntl(conn->sock, F_SETFD, FD_CLOEXEC) == -1)
					{
						appendPQExpBuffer(&conn->errorMessage,
										  libpq_gettext("could not set socket to close-on-exec mode: %s\n"),
							SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
						pqDropConnection(conn);
						conn->addr_cur = addr_cur->ai_next;
						continue;
					}
#endif   /* F_SETFD */

					if (!IS_AF_UNIX(addr_cur->ai_family))
					{
#ifndef WIN32
						int			on = 1;
#endif
						int			usekeepalives = useKeepalives(conn);
						int			err = 0;

						if (usekeepalives < 0)
						{
							appendPQExpBufferStr(&conn->errorMessage,
												 libpq_gettext("keepalives parameter must be an integer\n"));
							err = 1;
						}
						else if (usekeepalives == 0)
						{
							/* Do nothing */
						}
#ifndef WIN32
						else if (setsockopt(conn->sock,
											SOL_SOCKET, SO_KEEPALIVE,
											(char *) &on, sizeof(on)) < 0)
						{
							appendPQExpBuffer(&conn->errorMessage,
											  libpq_gettext("setsockopt(SO_KEEPALIVE) failed: %s\n"),
							SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
							err = 1;
						}
						else if (!setKeepalivesIdle(conn)
								 || !setKeepalivesInterval(conn)
								 || !setKeepalivesCount(conn))
							err = 1;
#else							/* WIN32 */
#ifdef SIO_KEEPALIVE_VALS
						else if (!setKeepalivesWin32(conn))
							err = 1;
#endif   /* SIO_KEEPALIVE_VALS */
#endif   /* WIN32 */

						if (err)
						{
							pqDropConnection(conn);
							conn->addr_cur = addr_cur->ai_next;
							continue;
						}
					}

					/*----------
					 * We have three methods of blocking SIGPIPE during
					 * send() calls to this socket:
					 *
					 *	- setsockopt(sock, SO_NOSIGPIPE)
					 *	- send(sock, ..., MSG_NOSIGNAL)
					 *	- setting the signal mask to SIG_IGN during send()
					 *
					 * The third method requires three syscalls per send,
					 * so we prefer either of the first two, but they are
					 * less portable.  The state is tracked in the following
					 * members of PGconn:
					 *
					 * conn->sigpipe_so		- we have set up SO_NOSIGPIPE
					 * conn->sigpipe_flag	- we're specifying MSG_NOSIGNAL
					 *
					 * If we can use SO_NOSIGPIPE, then set sigpipe_so here
					 * and we're done.  Otherwise, set sigpipe_flag so that
					 * we will try MSG_NOSIGNAL on sends.  If we get an error
					 * with MSG_NOSIGNAL, we'll clear that flag and revert to
					 * signal masking.
					 *----------
					 */
					conn->sigpipe_so = false;
#ifdef MSG_NOSIGNAL
					conn->sigpipe_flag = true;
#else
					conn->sigpipe_flag = false;
#endif   /* MSG_NOSIGNAL */

#ifdef SO_NOSIGPIPE
					optval = 1;
					if (setsockopt(conn->sock, SOL_SOCKET, SO_NOSIGPIPE,
								   (char *) &optval, sizeof(optval)) == 0)
					{
						conn->sigpipe_so = true;
						conn->sigpipe_flag = false;
					}
#endif   /* SO_NOSIGPIPE */

					/*
					 * Start/make connection.  This should not block, since we
					 * are in nonblock mode.  If it does, well, too bad.
					 */
					if (connect(conn->sock, addr_cur->ai_addr,
								addr_cur->ai_addrlen) < 0)
					{
						if (SOCK_ERRNO == EINPROGRESS ||
#ifdef WIN32
							SOCK_ERRNO == EWOULDBLOCK ||
#endif
							SOCK_ERRNO == EINTR)
						{
							/*
							 * This is fine - we're in non-blocking mode, and
							 * the connection is in progress.  Tell caller to
							 * wait for write-ready on socket.
							 */
							conn->status = CONNECTION_STARTED;
							return PGRES_POLLING_WRITING;
						}
						/* otherwise, trouble */
					}
					else
					{
						/*
						 * Hm, we're connected already --- seems the "nonblock
						 * connection" wasn't.  Advance the state machine and
						 * go do the next stuff.
						 */
						conn->status = CONNECTION_STARTED;
						goto keep_going;
					}

					/*
					 * This connection failed --- set up error report, then
					 * close socket (do it this way in case close() affects
					 * the value of errno...).	We will ignore the connect()
					 * failure and keep going if there are more addresses.
					 */
					connectFailureMessage(conn, SOCK_ERRNO);
					pqDropConnection(conn);

					/*
					 * Try the next address, if any.
					 */
					conn->addr_cur = addr_cur->ai_next;
				}				/* loop over addresses */

				/*
				 * Ooops, no more addresses.  An appropriate error message is
				 * already set up, so just set the right status.
				 */
				goto error_return;
			}

		case CONNECTION_STARTED:
			{
				ACCEPT_TYPE_ARG3 optlen = sizeof(optval);

				/*
				 * Write ready, since we've made it here, so the connection
				 * has been made ... or has failed.
				 */

				/*
				 * Now check (using getsockopt) that there is not an error
				 * state waiting for us on the socket.
				 */

				if (getsockopt(conn->sock, SOL_SOCKET, SO_ERROR,
							   (char *) &optval, &optlen) == -1)
				{
					appendPQExpBuffer(&conn->errorMessage,
					libpq_gettext("could not get socket error status: %s\n"),
							SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
					goto error_return;
				}
				else if (optval != 0)
				{
					/*
					 * When using a nonblocking connect, we will typically see
					 * connect failures at this point, so provide a friendly
					 * error message.
					 */
					connectFailureMessage(conn, optval);
					pqDropConnection(conn);

					/*
					 * If more addresses remain, keep trying, just as in the
					 * case where connect() returned failure immediately.
					 */
					if (conn->addr_cur->ai_next != NULL)
					{
						conn->addr_cur = conn->addr_cur->ai_next;
						conn->status = CONNECTION_NEEDED;
						goto keep_going;
					}
					goto error_return;
				}

				/* Fill in the client address */
				conn->laddr.salen = sizeof(conn->laddr.addr);
				if (getsockname(conn->sock,
								(struct sockaddr *) & conn->laddr.addr,
								&conn->laddr.salen) < 0)
				{
					appendPQExpBuffer(&conn->errorMessage,
									  libpq_gettext("could not get client address from socket: %s\n"),
							SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
					goto error_return;
				}

				/*
				 * Make sure we can write before advancing to next step.
				 */
				conn->status = CON…