fe-connect.c

关系型数据库 Postgresql 6.5.2

	SOCKET_SIZE_TYPE laddrlen;
	int			portno,
				family;
	char		beresp;
	int			on = 1;

	/*
	 * parse dbName to get all additional info in it, if any
	 */
	if (update_db_info(conn) != 0)
		goto connect_errReturn;

	/*
	 * Initialize the startup packet.
	 */

	MemSet((char *) &sp, 0, sizeof(StartupPacket));

	sp.protoVersion = (ProtocolVersion) htonl(PG_PROTOCOL_LIBPQ);

	strncpy(sp.user, conn->pguser, SM_USER);
	strncpy(sp.database, conn->dbName, SM_DATABASE);
	strncpy(sp.tty, conn->pgtty, SM_TTY);

	if (conn->pgoptions)
		strncpy(sp.options, conn->pgoptions, SM_OPTIONS);

	/*
	 * Open a connection to postmaster/backend.
	 */

	if (conn->pghost != NULL)
	{
		hp = gethostbyname(conn->pghost);
		if ((hp == NULL) || (hp->h_addrtype != AF_INET))
		{
			(void) sprintf(conn->errorMessage,
						   "connectDB() --  unknown hostname: %s\n",
						   conn->pghost);
			goto connect_errReturn;
		}
		family = AF_INET;
	}
	else
	{
		hp = NULL;
		family = AF_UNIX;
	}

	MemSet((char *) &conn->raddr, 0, sizeof(conn->raddr));
	conn->raddr.sa.sa_family = family;

	portno = atoi(conn->pgport);
	if (family == AF_INET)
	{
		memmove((char *) &(conn->raddr.in.sin_addr),
				(char *) hp->h_addr,
				hp->h_length);
		conn->raddr.in.sin_port = htons((unsigned short) (portno));
		conn->raddr_len = sizeof(struct sockaddr_in);
	}
#if !defined(WIN32) && !defined(__CYGWIN32__)
	else
		conn->raddr_len = UNIXSOCK_PATH(conn->raddr.un, portno);
#endif


	/* Connect to the server  */
	if ((conn->sock = socket(family, SOCK_STREAM, 0)) < 0)
	{
		(void) sprintf(conn->errorMessage,
					   "connectDB() -- socket() failed: errno=%d\n%s\n",
					   errno, strerror(errno));
		goto connect_errReturn;
	}
	if (connect(conn->sock, &conn->raddr.sa, conn->raddr_len) < 0)
	{
		(void) sprintf(conn->errorMessage,
					   "connectDB() -- connect() failed: %s\n"
					   "Is the postmaster running%s at '%s' and accepting connections on %s '%s'?\n",
					   strerror(errno),
					   (family == AF_INET) ? " (with -i)" : "",
					   conn->pghost ? conn->pghost : "localhost",
					 (family == AF_INET) ? "TCP/IP port" : "Unix socket",
					   conn->pgport);
		goto connect_errReturn;
	}

	/*
	 * Set the right options. We need nonblocking I/O, and we don't want
	 * delay of outgoing data.
	 */

#ifndef WIN32
	if (fcntl(conn->sock, F_SETFL, O_NONBLOCK) < 0)
#else
	if (ioctlsocket(conn->sock, FIONBIO, &on) != 0)
#endif
	{
		(void) sprintf(conn->errorMessage,
					   "connectDB() -- fcntl() failed: errno=%d\n%s\n",
					   errno, strerror(errno));
		goto connect_errReturn;
	}

	if (family == AF_INET)
	{
		struct protoent *pe;

		pe = getprotobyname("TCP");
		if (pe == NULL)
		{
			(void) sprintf(conn->errorMessage,
						   "connectDB(): getprotobyname failed\n");
			goto connect_errReturn;
		}
		if (setsockopt(conn->sock, pe->p_proto, TCP_NODELAY,
#ifdef WIN32
					   (char *)
#endif
					   &on,
					   sizeof(on)) < 0)
		{
			(void) sprintf(conn->errorMessage,
					  "connectDB() -- setsockopt failed: errno=%d\n%s\n",
						   errno, strerror(errno));
#ifdef WIN32
			printf("Winsock error: %i\n", WSAGetLastError());
#endif
			goto connect_errReturn;
		}
	}

	/* Fill in the client address */
	laddrlen = sizeof(conn->laddr);
	if (getsockname(conn->sock, &conn->laddr.sa, &laddrlen) < 0)
	{
		(void) sprintf(conn->errorMessage,
				   "connectDB() -- getsockname() failed: errno=%d\n%s\n",
					   errno, strerror(errno));
		goto connect_errReturn;
	}

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

	/* Send the startup packet. */

	if (pqPacketSend(conn, (char *) &sp, sizeof(StartupPacket)) != STATUS_OK)
	{
		sprintf(conn->errorMessage,
		  "connectDB() --  couldn't send startup packet: errno=%d\n%s\n",
				errno, strerror(errno));
		goto connect_errReturn;
	}

	/*
	 * Perform the authentication exchange: wait for backend messages and
	 * respond as necessary. We fall out of this loop when done talking to
	 * the postmaster.
	 */

	for (;;)
	{
		/* Wait for some data to arrive (or for the channel to close) */
		if (pqWait(TRUE, FALSE, conn))
			goto connect_errReturn;
		/* Load data, or detect EOF */
		if (pqReadData(conn) < 0)
			goto connect_errReturn;

		/*
		 * Scan the message. If we run out of data, loop around to try
		 * again.
		 */
		conn->inCursor = conn->inStart;

		if (pqGetc(&beresp, conn))
			continue;			/* no data yet */

		/* Handle errors. */
		if (beresp == 'E')
		{
			if (pqGets(conn->errorMessage, sizeof(conn->errorMessage), conn))
				continue;
			goto connect_errReturn;
		}

		/* Otherwise it should be an authentication request. */
		if (beresp != 'R')
		{
			(void) sprintf(conn->errorMessage,
					 "connectDB() -- expected authentication request\n");
			goto connect_errReturn;
		}

		/* Get the type of request. */
		if (pqGetInt((int *) &areq, 4, conn))
			continue;

		/* Get the password salt if there is one. */
		if (areq == AUTH_REQ_CRYPT)
		{
			if (pqGetnchar(conn->salt, sizeof(conn->salt), conn))
				continue;
		}

		/* OK, we successfully read the message; mark data consumed */
		conn->inStart = conn->inCursor;

		/* Respond to the request if necessary. */
		if (fe_sendauth(areq, conn, conn->pghost, conn->pgpass,
						conn->errorMessage) != STATUS_OK)
			goto connect_errReturn;
		if (pqFlush(conn))
			goto connect_errReturn;

		/* Are we done? */
		if (areq == AUTH_REQ_OK)
			break;
	}

	/*
	 * Now we expect to hear from the backend. A ReadyForQuery message
	 * indicates that startup is successful, but we might also get an
	 * Error message indicating failure. (Notice messages indicating
	 * nonfatal warnings are also allowed by the protocol, as is a
	 * BackendKeyData message.) Easiest way to handle this is to let
	 * PQgetResult() read the messages. We just have to fake it out about
	 * the state of the connection.
	 */

	conn->status = CONNECTION_OK;
	conn->asyncStatus = PGASYNC_BUSY;
	res = PQgetResult(conn);
	/* NULL return indicating we have gone to IDLE state is expected */
	if (res)
	{
		if (res->resultStatus != PGRES_FATAL_ERROR)
			sprintf(conn->errorMessage,
					"connectDB() -- unexpected message during startup\n");
		PQclear(res);
		goto connect_errReturn;
	}

	/*
	 * Given the new protocol that sends a ReadyForQuery message after
	 * successful backend startup, it should no longer be necessary to
	 * send an empty query to test for startup.
	 */

#ifdef NOT_USED

	/*
	 * Send a blank query to make sure everything works; in particular,
	 * that the database exists.
	 */
	res = PQexec(conn, " ");
	if (res == NULL || res->resultStatus != PGRES_EMPTY_QUERY)
	{
		/* PQexec has put error message in conn->errorMessage */
		closePGconn(conn);
		PQclear(res);
		goto connect_errReturn;
	}
	PQclear(res);

#endif

	/*
	 * Post-connection housekeeping. Send environment variables to server
	 */

	PQsetenv(conn);

	return CONNECTION_OK;

connect_errReturn:
	if (conn->sock >= 0)
	{
#ifdef WIN32
		closesocket(conn->sock);
#else
		close(conn->sock);
#endif
		conn->sock = -1;
	}
	return CONNECTION_BAD;

}

void
PQsetenv(PGconn *conn)
{
	struct EnvironmentOptions *eo;
	char		setQuery[80];	/* mjl: size okay? XXX */

#ifdef MULTIBYTE
	char	   *envname = "PGCLIENTENCODING";
	static char envbuf[64];		/* big enough? */
	char	   *env;
	char	   *encoding = 0;
	PGresult   *rtn;

#endif

#ifdef MULTIBYTE
	/* query server encoding */
	env = getenv(envname);
	if (!env || *env == '\0')
	{
		rtn = PQexec(conn, "select getdatabaseencoding()");
		if (rtn && PQresultStatus(rtn) == PGRES_TUPLES_OK)
		{
			encoding = PQgetvalue(rtn, 0, 0);
			if (encoding)
			{
				/* set client encoding */
				sprintf(envbuf, "%s=%s", envname, encoding);
				putenv(envbuf);
			}
		}
		PQclear(rtn);
		if (!encoding)
		{						/* this should not happen */
			sprintf(envbuf, "%s=%s", envname, pg_encoding_to_char(MULTIBYTE));
			putenv(envbuf);
		}
	}
#endif

	for (eo = EnvironmentOptions; eo->envName; eo++)
	{
		const char *val;

		if ((val = getenv(eo->envName)))
		{
			PGresult   *res;

			if (strcasecmp(val, "default") == 0)
				sprintf(setQuery, "SET %s = %.60s", eo->pgName, val);
			else
				sprintf(setQuery, "SET %s = '%.60s'", eo->pgName, val);
#ifdef CONNECTDEBUG
			printf("Use environment variable %s to send %s\n", eo->envName, setQuery);
#endif
			res = PQexec(conn, setQuery);
			PQclear(res);		/* Don't care? */
		}
	}
}	/* PQsetenv() */

/*
 * makeEmptyPGconn
 *	 - create a PGconn data structure with (as yet) no interesting data
 */
static PGconn *
makeEmptyPGconn(void)
{
	PGconn	   *conn = (PGconn *) malloc(sizeof(PGconn));

	if (conn == NULL)
		return conn;

	/* Zero all pointers */
	MemSet((char *) conn, 0, sizeof(PGconn));

	conn->noticeHook = defaultNoticeProcessor;
	conn->status = CONNECTION_BAD;
	conn->asyncStatus = PGASYNC_IDLE;
	conn->notifyList = DLNewList();
	conn->sock = -1;
	conn->inBufSize = PQ_BUFFER_SIZE;
	conn->inBuffer = (char *) malloc(conn->inBufSize);
	conn->outBufSize = PQ_BUFFER_SIZE;
	conn->outBuffer = (char *) malloc(conn->outBufSize);
	if (conn->inBuffer == NULL || conn->outBuffer == NULL)
	{
		freePGconn(conn);
		conn = NULL;
	}
	return conn;
}

/*
 * freePGconn
 *	 - free the PGconn data structure
 *
 */
static void
freePGconn(PGconn *conn)
{
	if (!conn)
		return;
	pqClearAsyncResult(conn);	/* deallocate result and curTuple */
	if (conn->sock >= 0)
#ifdef WIN32
		closesocket(conn->sock);
#else
		close(conn->sock);
#endif
	if (conn->pghost)
		free(conn->pghost);
	if (conn->pgport)
		free(conn->pgport);
	if (conn->pgtty)
		free(conn->pgtty);
	if (conn->pgoptions)
		free(conn->pgoptions);
	if (conn->dbName)
		free(conn->dbName);
	if (conn->pguser)
		free(conn->pguser);
	if (conn->pgpass)
		free(conn->pgpass);
	/* Note that conn->Pfdebug is not ours to close or free */
	if (conn->notifyList)
		DLFreeList(conn->notifyList);
	if (conn->lobjfuncs)
		free(conn->lobjfuncs);
	if (conn->inBuffer)
		free(conn->inBuffer);
	if (conn->outBuffer)
		free(conn->outBuffer);
	free(conn);
}

/*
   closePGconn
	 - properly close a connection to the backend
*/
static void
closePGconn(PGconn *conn)
{
	if (conn->sock >= 0)
	{

		/*
		 * Try to send "close connection" message to backend. Ignore any
		 * error. Note: this routine used to go to substantial lengths to
		 * avoid getting SIGPIPE'd if the connection were already closed.
		 * Now we rely on pqFlush to avoid the signal.
		 */
		(void) pqPuts("X", conn);
		(void) pqFlush(conn);
	}

	/*
	 * Close the connection, reset all transient state, flush I/O buffers.
	 */
	if (conn->sock >= 0)
#ifdef WIN32
		closesocket(conn->sock);
#else
		close(conn->sock);
#endif
	conn->sock = -1;
	conn->status = CONNECTION_BAD;		/* Well, not really _bad_ - just
										 * absent */
	conn->asyncStatus = PGASYNC_IDLE;
	pqClearAsyncResult(conn);	/* deallocate result and curTuple */
	if (conn->lobjfuncs)
		free(conn->lobjfuncs);
	conn->lobjfuncs = NULL;
	conn->inStart = conn->inCursor = conn->inEnd = 0;
	conn->outCount = 0;

}

/*
   PQfinish:
	  properly close a connection to the backend
	  also frees the PGconn data structure so it shouldn't be re-used
	  after this
*/
void
PQfinish(PGconn *conn)
{
	if (conn)
	{
		closePGconn(conn);
		freePGconn(conn);
	}
}

/* PQreset :
   resets the connection to the backend
   closes the existing connection and makes a new one
*/
void
PQreset(PGconn *conn)
{
	if (conn)
	{
		closePGconn(conn);
		conn->status = connectDB(conn);
	}
}


/*