uxplink.c

远程登陆工具软件源码 用于远程登陆unix

		    char *r;
		    /*
		     * Before we process the [user@]host string, we
		     * first check for the presence of a protocol
		     * prefix (a protocol name followed by ",").
		     */
		    r = strchr(p, ',');
		    if (r) {
			int i, j;
			for (i = 0; backends[i].backend != NULL; i++) {
			    j = strlen(backends[i].name);
			    if (j == r - p &&
				!memcmp(backends[i].name, p, j)) {
				default_protocol = cfg.protocol =
				    backends[i].protocol;
				portnumber =
				    backends[i].backend->default_port;
				p = r + 1;
				break;
			    }
			}
		    }

		    /*
		     * 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;

    /*
     * Set up the pipe we'll use to tell us about SIGWINCH.
     */
    if (pipe(signalpipe) < 0) {
	perror("pipe");
	exit(1);
    }
    putty_signal(SIGWINCH, sigwinch);

    sk_init();
    uxsel_init();

    /*
     * Start up the connection.
     */
    logctx = log_init(NULL, &cfg);
    console_provide_logctx(logctx);
    {
	const char *error;
	char *realhost;
	/* nodelay is only useful if stdin is a terminal device */
	int nodelay = cfg.tcp_nodelay && isatty(0);

	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\n", error);
	    return 1;
	}
	back->provide_logctx(backhandle, logctx);
	ldisc = ldisc_create(&cfg, NULL, back, backhandle, NULL);
	sfree(realhost);
    }
    connopen = 1;

    /*
     * Set up the initial console mode. We don't care if this call
     * fails, because we know we aren't necessarily running in a
     * console.
     */
    tcgetattr(0, &orig_termios);
    atexit(cleanup_termios);
    ldisc_update(NULL, 1, 1);
    sending = FALSE;

    while (1) {
	fd_set rset, wset, xset;
	int maxfd;
	int rwx;
	int ret;

	FD_ZERO(&rset);
	FD_ZERO(&wset);
	FD_ZERO(&xset);
	maxfd = 0;

	FD_SET_MAX(signalpipe[0], maxfd, rset);

	if (connopen && !sending &&
	    back->socket(backhandle) != NULL &&
	    back->sendok(backhandle) &&
	    back->sendbuffer(backhandle) < MAX_STDIN_BACKLOG) {
	    /* If we're OK to send, then try to read from stdin. */
	    FD_SET_MAX(0, maxfd, rset);
	}

	if (bufchain_size(&stdout_data) > 0) {
	    /* If we have data for stdout, try to write to stdout. */
	    FD_SET_MAX(1, maxfd, wset);
	}

	if (bufchain_size(&stderr_data) > 0) {
	    /* If we have data for stderr, try to write to stderr. */
	    FD_SET_MAX(2, maxfd, wset);
	}

	/* Count the currently active fds. */
	i = 0;
	for (fd = first_fd(&fdstate, &rwx); fd >= 0;
	     fd = next_fd(&fdstate, &rwx)) i++;

	/* Expand the fdlist buffer if necessary. */
	if (i > fdsize) {
	    fdsize = i + 16;
	    fdlist = sresize(fdlist, fdsize, int);
	}

	/*
	 * Add all currently open fds to the select sets, and store
	 * them in fdlist as well.
	 */
	fdcount = 0;
	for (fd = first_fd(&fdstate, &rwx); fd >= 0;
	     fd = next_fd(&fdstate, &rwx)) {
	    fdlist[fdcount++] = fd;
	    if (rwx & 1)
		FD_SET_MAX(fd, maxfd, rset);
	    if (rwx & 2)
		FD_SET_MAX(fd, maxfd, wset);
	    if (rwx & 4)
		FD_SET_MAX(fd, maxfd, xset);
	}

	do {
	    ret = select(maxfd, &rset, &wset, &xset, NULL);
	} while (ret < 0 && errno == EINTR);

	if (ret < 0) {
	    perror("select");
	    exit(1);
	}

	for (i = 0; i < fdcount; i++) {
	    fd = fdlist[i];
            /*
             * We must process exceptional notifications before
             * ordinary readability ones, or we may go straight
             * past the urgent marker.
             */
	    if (FD_ISSET(fd, &xset))
		select_result(fd, 4);
	    if (FD_ISSET(fd, &rset))
		select_result(fd, 1);
	    if (FD_ISSET(fd, &wset))
		select_result(fd, 2);
	}

	if (FD_ISSET(signalpipe[0], &rset)) {
	    char c[1];
	    struct winsize size;
	    read(signalpipe[0], c, 1); /* ignore its value; it'll be `x' */
	    if (ioctl(0, TIOCGWINSZ, (void *)&size) >= 0)
		back->size(backhandle, size.ws_col, size.ws_row);
	}

	if (FD_ISSET(0, &rset)) {
	    char buf[4096];
	    int ret;

	    if (connopen && back->socket(backhandle) != NULL) {
		ret = read(0, buf, sizeof(buf));
		if (ret < 0) {
		    perror("stdin: read");
		    exit(1);
		} else if (ret == 0) {
		    back->special(backhandle, TS_EOF);
		    sending = FALSE;   /* send nothing further after this */
		} else {
		    back->send(backhandle, buf, ret);
		}
	    }
	}

	if (FD_ISSET(1, &wset)) {
	    try_output(0);
	}

	if (FD_ISSET(2, &wset)) {
	    try_output(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 exitcode;		       /* shouldn't happen, but placates gcc */
}