+ * Work out the device name, if it hasn't already been specified.
+ */
+ using_pty = notty || ptycommand != NULL;
+ if (!using_pty && default_device) {
+ char *p;
+ if (!isatty(0) || (p = ttyname(0)) == NULL) {
+ option_error("no device specified and stdin is not a tty");
+ exit(EXIT_OPTION_ERROR);
+ }
+ strlcpy(devnam, p, sizeof(devnam));
+ if (stat(devnam, &devstat) < 0)
+ fatal("Couldn't stat default device %s: %m", devnam);
+ }
+
+ /*
+ * Parse the tty options file and the command line.
+ * The per-tty options file should not change
+ * ptycommand, notty or devnam.
+ */
+ devnam_fixed = 1;
+ if (!using_pty) {
+ if (!options_for_tty())
+ exit(EXIT_OPTION_ERROR);
+ }
+
+ devnam_fixed = 0;
+ if (!parse_args(argc-1, argv+1))
+ exit(EXIT_OPTION_ERROR);
+
+ /*
+ * Check that we are running as root.
+ */
+ if (geteuid() != 0) {
+ option_error("must be root to run %s, since it is not setuid-root",
+ argv[0]);
+ exit(EXIT_NOT_ROOT);
+ }
+
+ if (!ppp_available()) {
+ option_error(no_ppp_msg);
+ exit(EXIT_NO_KERNEL_SUPPORT);
+ }
+
+ /*
+ * Check that the options given are valid and consistent.
+ */
+ if (!sys_check_options())
+ exit(EXIT_OPTION_ERROR);
+ auth_check_options();
+ for (i = 0; (protp = protocols[i]) != NULL; ++i)
+ if (protp->check_options != NULL)
+ (*protp->check_options)();
+ if (demand && connector == 0) {
+ option_error("connect script is required for demand-dialling\n");
+ exit(EXIT_OPTION_ERROR);
+ }
+ /* default holdoff to 0 if no connect script has been given */
+ if (connector == 0 && !holdoff_specified)
+ holdoff = 0;
+
+ if (using_pty) {
+ if (!default_device) {
+ option_error("%s option precludes specifying device name",
+ notty? "notty": "pty");
+ exit(EXIT_OPTION_ERROR);
+ }
+ if (ptycommand != NULL && notty) {
+ option_error("pty option is incompatible with notty option");
+ exit(EXIT_OPTION_ERROR);
+ }
+ default_device = notty;
+ lockflag = 0;
+ modem = 0;
+ if (notty && log_to_fd <= 1)
+ log_to_fd = -1;
+ } else {
+ /*
+ * If the user has specified a device which is the same as
+ * the one on stdin, pretend they didn't specify any.
+ * If the device is already open read/write on stdin,
+ * we assume we don't need to lock it, and we can open it as root.
+ */
+ if (fstat(0, &statbuf) >= 0 && S_ISCHR(statbuf.st_mode)
+ && statbuf.st_rdev == devstat.st_rdev) {
+ default_device = 1;
+ fdflags = fcntl(0, F_GETFL);
+ if (fdflags != -1 && (fdflags & O_ACCMODE) == O_RDWR)
+ privopen = 1;
+ }
+ }
+ if (default_device)
+ nodetach = 1;
+
+ /*
+ * Don't send log messages to the serial port, it tends to
+ * confuse the peer. :-)
+ */
+ if (log_to_fd >= 0 && fstat(log_to_fd, &statbuf) >= 0
+ && S_ISCHR(statbuf.st_mode) && statbuf.st_rdev == devstat.st_rdev)
+ log_to_fd = -1;
+
+ script_setenv("DEVICE", devnam);
+
+ /*
+ * Initialize system-dependent stuff.