/*
		     * Three cases. Either (a) there's a nonzero
		     * length string followed by an @, in which
		     * case that's user and the remainder is host.
		     * Or (b) there's only one string, not counting
		     * a potential initial @, and it exists in the
		     * saved-sessions database. Or (c) only one
		     * string and it _doesn't_ exist in the
		     * database.
		     */
		    r = strrchr(p, '@');
		    if (r == p)
			p++, r = NULL; /* discount initial @ */
		    if (r == NULL) {
			/*
			 * One string.
			 */
			Config cfg2;
			do_defaults(p, &cfg2);
			if (loaded_session || cfg2.host[0] == '\0') {
			    /* No settings for this host; use defaults */
			    /* (or session was already loaded with -load) */
			    strncpy(cfg.host, p, sizeof(cfg.host) - 1);
			    cfg.host[sizeof(cfg.host) - 1] = '\0';
			    cfg.port = default_port;
			} else {
			    cfg = cfg2;
			    /* Ick: patch up internal pointer after copy */
			    cfg.remote_cmd_ptr = cfg.remote_cmd;
			}
		    } else {
			*r++ = '\0';
			strncpy(cfg.username, p, sizeof(cfg.username) - 1);
			cfg.username[sizeof(cfg.username) - 1] = '\0';
			strncpy(cfg.host, r, sizeof(cfg.host) - 1);
			cfg.host[sizeof(cfg.host) - 1] = '\0';
			cfg.port = default_port;
		    }
		}
	    } else {
		char *command;
		int cmdlen, cmdsize;
		cmdlen = cmdsize = 0;
		command = NULL;

		while (argc) {
		    while (*p) {
			if (cmdlen >= cmdsize) {
			    cmdsize = cmdlen + 512;
			    command = sresize(command, cmdsize, char);
			}
			command[cmdlen++]=*p++;
		    }
		    if (cmdlen >= cmdsize) {
			cmdsize = cmdlen + 512;
			command = sresize(command, cmdsize, char);
		    }
		    command[cmdlen++]=' '; /* always add trailing space */
		    if (--argc) p = *++argv;
		}
		if (cmdlen) command[--cmdlen]='\0';
				       /* change trailing blank to NUL */
		cfg.remote_cmd_ptr = command;
		cfg.remote_cmd_ptr2 = NULL;
		cfg.nopty = TRUE;      /* command => no terminal */

		break;		       /* done with cmdline */
	    }
	}
    }

    if (errors)
	return 1;

    if (!*cfg.host) {
	usage();
    }

    /*
     * Trim leading whitespace off the hostname if it's there.
     */
    {
	int space = strspn(cfg.host, " \t");
	memmove(cfg.host, cfg.host+space, 1+strlen(cfg.host)-space);
    }

    /* See if host is of the form user@host */
    if (cfg.host[0] != '\0') {
	char *atsign = strchr(cfg.host, '@');
	/* Make sure we're not overflowing the user field */
	if (atsign) {
	    if (atsign - cfg.host < sizeof cfg.username) {
		strncpy(cfg.username, cfg.host, atsign - cfg.host);
		cfg.username[atsign - cfg.host] = '\0';
	    }
	    memmove(cfg.host, atsign + 1, 1 + strlen(atsign + 1));
	}
    }

    /*
     * Perform command-line overrides on session configuration.
     */
    cmdline_run_saved(&cfg);

    /*
     * Apply subsystem status.
     */
    if (use_subsystem)
	cfg.ssh_subsys = TRUE;

    /*
     * Trim a colon suffix off the hostname if it's there.
     */
    cfg.host[strcspn(cfg.host, ":")] = '\0';

    /*
     * Remove any remaining whitespace from the hostname.
     */
    {
	int p1 = 0, p2 = 0;
	while (cfg.host[p2] != '\0') {
	    if (cfg.host[p2] != ' ' && cfg.host[p2] != '\t') {
		cfg.host[p1] = cfg.host[p2];
		p1++;
	    }
	    p2++;
	}
	cfg.host[p1] = '\0';
    }

    if (!*cfg.remote_cmd_ptr)
	flags |= FLAG_INTERACTIVE;

    /*
     * Select protocol. This is farmed out into a table in a
     * separate file to enable an ssh-free variant.
     */
    {
	int i;
	back = NULL;
	for (i = 0; backends[i].backend != NULL; i++)
	    if (backends[i].protocol == cfg.protocol) {
		back = backends[i].backend;
		break;
	    }
	if (back == NULL) {
	    fprintf(stderr,
		    "Internal fault: Unsupported protocol found\n");
	    return 1;
	}
    }

    /*
     * Select port.
     */
    if (portnumber != -1)
	cfg.port = portnumber;

    sk_init();
    if (p_WSAEventSelect == NULL) {
	fprintf(stderr, "Plink requires WinSock 2\n");
	return 1;
    }

    /*
     * Start up the connection.
     */
    netevent = CreateEvent(NULL, FALSE, FALSE, NULL);
    {
	const char *error;
	char *realhost;
	/* nodelay is only useful if stdin is a character device (console) */
	int nodelay = cfg.tcp_nodelay &&
	    (GetFileType(GetStdHandle(STD_INPUT_HANDLE)) == FILE_TYPE_CHAR);

	error = back->init(NULL, &backhandle, &cfg, cfg.host, cfg.port,
			   &realhost, nodelay, cfg.tcp_keepalives);
	if (error) {
	    fprintf(stderr, "Unable to open connection:\n%s", error);
	    return 1;
	}
	logctx = log_init(NULL, &cfg);
	back->provide_logctx(backhandle, logctx);
	console_provide_logctx(logctx);
	sfree(realhost);
    }
    connopen = 1;

    stdinevent = CreateEvent(NULL, FALSE, FALSE, NULL);
    stdoutevent = CreateEvent(NULL, FALSE, FALSE, NULL);
    stderrevent = CreateEvent(NULL, FALSE, FALSE, NULL);

    inhandle = GetStdHandle(STD_INPUT_HANDLE);
    outhandle = GetStdHandle(STD_OUTPUT_HANDLE);
    errhandle = GetStdHandle(STD_ERROR_HANDLE);
    GetConsoleMode(inhandle, &orig_console_mode);
    SetConsoleMode(inhandle, ENABLE_PROCESSED_INPUT);

    main_thread_id = GetCurrentThreadId();

    /*
     * Turn off ECHO and LINE input modes. We don't care if this
     * call fails, because we know we aren't necessarily running in
     * a console.
     */
    handles[0] = netevent;
    handles[1] = stdinevent;
    handles[2] = stdoutevent;
    handles[3] = stderrevent;
    sending = FALSE;

    /*
     * Create spare threads to write to stdout and stderr, so we
     * can arrange asynchronous writes.
     */
    odata.event = stdoutevent;
    odata.eventback = CreateEvent(NULL, FALSE, FALSE, NULL);
    odata.is_stderr = 0;
    odata.busy = odata.done = 0;
    if (!CreateThread(NULL, 0, stdout_write_thread,
		      &odata, 0, &out_threadid)) {
	fprintf(stderr, "Unable to create output thread\n");
	cleanup_exit(1);
    }
    edata.event = stderrevent;
    edata.eventback = CreateEvent(NULL, FALSE, FALSE, NULL);
    edata.is_stderr = 1;
    edata.busy = edata.done = 0;
    if (!CreateThread(NULL, 0, stdout_write_thread,
		      &edata, 0, &err_threadid)) {
	fprintf(stderr, "Unable to create error output thread\n");
	cleanup_exit(1);
    }

    while (1) {
	int n;

	if (!sending && back->sendok(backhandle)) {
	    /*
	     * Create a separate thread to read from stdin. This is
	     * a total pain, but I can't find another way to do it:
	     *
	     *  - an overlapped ReadFile or ReadFileEx just doesn't
	     *    happen; we get failure from ReadFileEx, and
	     *    ReadFile blocks despite being given an OVERLAPPED
	     *    structure. Perhaps we can't do overlapped reads
	     *    on consoles. WHY THE HELL NOT?
	     * 
	     *  - WaitForMultipleObjects(netevent, console) doesn't
	     *    work, because it signals the console when
	     *    _anything_ happens, including mouse motions and
	     *    other things that don't cause data to be readable
	     *    - so we're back to ReadFile blocking.
	     */
	    idata.event = stdinevent;
	    idata.eventback = CreateEvent(NULL, FALSE, FALSE, NULL);
	    if (!CreateThread(NULL, 0, stdin_read_thread,
			      &idata, 0, &in_threadid)) {
		fprintf(stderr, "Unable to create input thread\n");
		cleanup_exit(1);
	    }
	    sending = TRUE;
	}

	n = MsgWaitForMultipleObjects(4, handles, FALSE, INFINITE,
				      QS_POSTMESSAGE);
	if (n == 0) {
	    WSANETWORKEVENTS things;
	    SOCKET socket;
	    extern SOCKET first_socket(int *), next_socket(int *);
	    extern int select_result(WPARAM, LPARAM);
	    int i, socketstate;

	    /*
	     * We must not call select_result() for any socket
	     * until we have finished enumerating within the tree.
	     * This is because select_result() may close the socket
	     * and modify the tree.
	     */
	    /* Count the active sockets. */
	    i = 0;
	    for (socket = first_socket(&socketstate);
		 socket != INVALID_SOCKET;
		 socket = next_socket(&socketstate)) i++;

	    /* Expand the buffer if necessary. */
	    if (i > sksize) {
		sksize = i + 16;
		sklist = sresize(sklist, sksize, SOCKET);
	    }

	    /* Retrieve the sockets into sklist. */
	    skcount = 0;
	    for (socket = first_socket(&socketstate);
		 socket != INVALID_SOCKET;
		 socket = next_socket(&socketstate)) {
		sklist[skcount++] = socket;
	    }

	    /* Now we're done enumerating; go through the list. */
	    for (i = 0; i < skcount; i++) {
		WPARAM wp;
		socket = sklist[i];
		wp = (WPARAM) socket;
		if (!p_WSAEnumNetworkEvents(socket, NULL, &things)) {
                    static const struct { int bit, mask; } eventtypes[] = {
                        {FD_CONNECT_BIT, FD_CONNECT},
                        {FD_READ_BIT, FD_READ},
                        {FD_CLOSE_BIT, FD_CLOSE},
                        {FD_OOB_BIT, FD_OOB},
                        {FD_WRITE_BIT, FD_WRITE},
                        {FD_ACCEPT_BIT, FD_ACCEPT},
                    };
                    int e;

		    noise_ultralight(socket);
		    noise_ultralight(things.lNetworkEvents);

                    for (e = 0; e < lenof(eventtypes); e++)
                        if (things.lNetworkEvents & eventtypes[e].mask) {
                            LPARAM lp;
                            int err = things.iErrorCode[eventtypes[e].bit];
                            lp = WSAMAKESELECTREPLY(eventtypes[e].mask, err);
                            connopen &= select_result(wp, lp);
                        }
		}
	    }
	} else if (n == 1) {
	    reading = 0;
	    noise_ultralight(idata.len);
	    if (connopen && back->socket(backhandle) != NULL) {
		if (idata.len > 0) {
		    back->send(backhandle, idata.buffer, idata.len);
		} else {
		    back->special(backhandle, TS_EOF);
		}
	    }
	} else if (n == 2) {
	    odata.busy = 0;
	    if (!odata.writeret) {
		fprintf(stderr, "Unable to write to standard output\n");
		cleanup_exit(0);
	    }
	    bufchain_consume(&stdout_data, odata.lenwritten);
	    if (bufchain_size(&stdout_data) > 0)
		try_output(0);
	    if (connopen && back->socket(backhandle) != NULL) {
		back->unthrottle(backhandle, bufchain_size(&stdout_data) +
				 bufchain_size(&stderr_data));
	    }
	} else if (n == 3) {
	    edata.busy = 0;
	    if (!edata.writeret) {
		fprintf(stderr, "Unable to write to standard output\n");
		cleanup_exit(0);
	    }
	    bufchain_consume(&stderr_data, edata.lenwritten);
	    if (bufchain_size(&stderr_data) > 0)
		try_output(1);
	    if (connopen && back->socket(backhandle) != NULL) {
		back->unthrottle(backhandle, bufchain_size(&stdout_data) +
				 bufchain_size(&stderr_data));
	    }
	} else if (n == 4) {
	    MSG msg;
	    while (PeekMessage(&msg, INVALID_HANDLE_VALUE,
			       WM_AGENT_CALLBACK, WM_AGENT_CALLBACK,
			       PM_REMOVE)) {
		struct agent_callback *c = (struct agent_callback *)msg.lParam;
		c->callback(c->callback_ctx, c->data, c->len);
		sfree(c);
	    }
	}
	if (!reading && back->sendbuffer(backhandle) < MAX_STDIN_BACKLOG) {
	    SetEvent(idata.eventback);
	    reading = 1;
	}
	if ((!connopen || back->socket(backhandle) == NULL) &&
	    bufchain_size(&stdout_data) == 0 &&
	    bufchain_size(&stderr_data) == 0)
	    break;		       /* we closed the connection */
    }
    exitcode = back->exitcode(backhandle);
    if (exitcode < 0) {
	fprintf(stderr, "Remote process exit code unavailable\n");
	exitcode = 1;		       /* this is an error condition */
    }
    cleanup_exit(exitcode);
    return 0;			       /* placate compiler warning */
}