2 * tty.c - code for handling serial ports in pppd.
4 * Copyright (C) 2000-2004 Paul Mackerras. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
13 * 2. The name(s) of the authors of this software must not be used to
14 * endorse or promote products derived from this software without
15 * prior written permission.
17 * 3. Redistributions of any form whatsoever must retain the following
19 * "This product includes software developed by Paul Mackerras
20 * <paulus@samba.org>".
22 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
23 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
24 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
25 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
26 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
27 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
28 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
30 * Portions derived from main.c, which is:
32 * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
34 * Redistribution and use in source and binary forms, with or without
35 * modification, are permitted provided that the following conditions
38 * 1. Redistributions of source code must retain the above copyright
39 * notice, this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright
42 * notice, this list of conditions and the following disclaimer in
43 * the documentation and/or other materials provided with the
46 * 3. The name "Carnegie Mellon University" must not be used to
47 * endorse or promote products derived from this software without
48 * prior written permission. For permission or any legal
49 * details, please contact
50 * Office of Technology Transfer
51 * Carnegie Mellon University
53 * Pittsburgh, PA 15213-3890
54 * (412) 268-4387, fax: (412) 268-7395
55 * tech-transfer@andrew.cmu.edu
57 * 4. Redistributions of any form whatsoever must retain the following
59 * "This product includes software developed by Computing Services
60 * at Carnegie Mellon University (http://www.cmu.edu/computing/)."
62 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
63 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
64 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
65 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
66 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
67 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
68 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
71 #define RCSID "$Id: tty.c,v 1.27 2008/07/01 12:27:56 paulus Exp $"
86 #include <sys/param.h>
87 #include <sys/types.h>
90 #include <sys/resource.h>
92 #include <sys/socket.h>
93 #include <netinet/in.h>
94 #include <arpa/inet.h>
100 void tty_process_extra_options __P((void));
101 void tty_check_options __P((void));
102 int connect_tty __P((void));
103 void disconnect_tty __P((void));
104 void tty_close_fds __P((void));
105 void cleanup_tty __P((void));
106 void tty_do_send_config __P((int, u_int32_t, int, int));
108 static int setdevname __P((char *, char **, int));
109 static int setspeed __P((char *, char **, int));
110 static int setxonxoff __P((char **));
111 static int setescape __P((char **));
112 static void printescape __P((option_t *, void (*)(void *, char *,...),void *));
113 static void finish_tty __P((void));
114 static int start_charshunt __P((int, int));
115 static void stop_charshunt __P((void *, int));
116 static void charshunt_done __P((void *));
117 static void charshunt __P((int, int, char *));
118 static int record_write __P((FILE *, int code, u_char *buf, int nb,
120 static int open_socket __P((char *));
121 static void maybe_relock __P((void *, int));
123 static int pty_master; /* fd for master side of pty */
124 static int pty_slave; /* fd for slave side of pty */
125 static int real_ttyfd; /* fd for actual serial port (not pty) */
126 static int ttyfd; /* Serial port file descriptor */
127 static char speed_str[16]; /* Serial port speed as string */
129 mode_t tty_mode = (mode_t)-1; /* Original access permissions to tty */
130 int baud_rate; /* Actual bits/second for serial device */
131 char *callback_script; /* script for doing callback */
132 int charshunt_pid; /* Process ID for charshunt */
133 int locked; /* lock() has succeeded */
134 struct stat devstat; /* result of stat() on devnam */
136 /* option variables */
137 int crtscts = 0; /* Use hardware flow control */
138 int stop_bits = 1; /* Number of serial port stop bits */
139 bool modem = 1; /* Use modem control lines */
140 int inspeed = 0; /* Input/Output speed requested */
141 bool lockflag = 0; /* Create lock file to lock the serial dev */
142 char *initializer = NULL; /* Script to initialize physical link */
143 char *connect_script = NULL; /* Script to establish physical link */
144 char *disconnect_script = NULL; /* Script to disestablish physical link */
145 char *welcomer = NULL; /* Script to run after phys link estab. */
146 char *ptycommand = NULL; /* Command to run on other side of pty */
147 bool notty = 0; /* Stdin/out is not a tty */
148 char *record_file = NULL; /* File to record chars sent/received */
149 int max_data_rate; /* max bytes/sec through charshunt */
150 bool sync_serial = 0; /* Device is synchronous serial device */
151 char *pty_socket = NULL; /* Socket to connect to pty */
152 int using_pty = 0; /* we're allocating a pty as the device */
155 extern int kill_link;
156 extern int asked_to_quit;
157 extern int got_sigterm;
160 extern int privopen; /* don't lock, open device as root */
162 u_int32_t xmit_accm[8]; /* extended transmit ACCM */
164 /* option descriptors */
165 option_t tty_options[] = {
166 /* device name must be first, or change connect_tty() below! */
167 { "device name", o_wild, (void *) &setdevname,
168 "Serial port device name",
169 OPT_DEVNAM | OPT_PRIVFIX | OPT_NOARG | OPT_A2STRVAL | OPT_STATIC,
172 { "tty speed", o_wild, (void *) &setspeed,
173 "Baud rate for serial port",
174 OPT_PRIO | OPT_NOARG | OPT_A2STRVAL | OPT_STATIC, speed_str },
176 { "lock", o_bool, &lockflag,
177 "Lock serial device with UUCP-style lock file", OPT_PRIO | 1 },
178 { "nolock", o_bool, &lockflag,
179 "Don't lock serial device", OPT_PRIOSUB | OPT_PRIV },
181 { "init", o_string, &initializer,
182 "A program to initialize the device", OPT_PRIO | OPT_PRIVFIX },
184 { "connect", o_string, &connect_script,
185 "A program to set up a connection", OPT_PRIO | OPT_PRIVFIX },
187 { "disconnect", o_string, &disconnect_script,
188 "Program to disconnect serial device", OPT_PRIO | OPT_PRIVFIX },
190 { "welcome", o_string, &welcomer,
191 "Script to welcome client", OPT_PRIO | OPT_PRIVFIX },
193 { "pty", o_string, &ptycommand,
194 "Script to run on pseudo-tty master side",
195 OPT_PRIO | OPT_PRIVFIX | OPT_DEVNAM },
197 { "notty", o_bool, ¬ty,
198 "Input/output is not a tty", OPT_DEVNAM | 1 },
200 { "socket", o_string, &pty_socket,
201 "Send and receive over socket, arg is host:port",
202 OPT_PRIO | OPT_DEVNAM },
204 { "record", o_string, &record_file,
205 "Record characters sent/received to file", OPT_PRIO },
207 { "crtscts", o_int, &crtscts,
208 "Set hardware (RTS/CTS) flow control",
209 OPT_PRIO | OPT_NOARG | OPT_VAL(1) },
210 { "cdtrcts", o_int, &crtscts,
211 "Set alternate hardware (DTR/CTS) flow control",
212 OPT_PRIOSUB | OPT_NOARG | OPT_VAL(2) },
213 { "nocrtscts", o_int, &crtscts,
214 "Disable hardware flow control",
215 OPT_PRIOSUB | OPT_NOARG | OPT_VAL(-1) },
216 { "-crtscts", o_int, &crtscts,
217 "Disable hardware flow control",
218 OPT_PRIOSUB | OPT_ALIAS | OPT_NOARG | OPT_VAL(-1) },
219 { "nocdtrcts", o_int, &crtscts,
220 "Disable hardware flow control",
221 OPT_PRIOSUB | OPT_ALIAS | OPT_NOARG | OPT_VAL(-1) },
222 { "xonxoff", o_special_noarg, (void *)setxonxoff,
223 "Set software (XON/XOFF) flow control", OPT_PRIOSUB },
224 { "stop-bits", o_int, &stop_bits,
225 "Number of stop bits in serial port",
226 OPT_PRIO | OPT_PRIVFIX | OPT_LIMITS, NULL, 2, 1 },
228 { "modem", o_bool, &modem,
229 "Use modem control lines", OPT_PRIO | 1 },
230 { "local", o_bool, &modem,
231 "Don't use modem control lines", OPT_PRIOSUB | 0 },
233 { "sync", o_bool, &sync_serial,
234 "Use synchronous HDLC serial encoding", 1 },
236 { "datarate", o_int, &max_data_rate,
237 "Maximum data rate in bytes/sec (with pty, notty or record option)",
240 { "escape", o_special, (void *)setescape,
241 "List of character codes to escape on transmission",
242 OPT_A2PRINTER, (void *)printescape },
248 struct channel tty_channel = {
250 &tty_process_extra_options,
255 &tty_disestablish_ppp,
263 * setspeed - Set the serial port baud rate.
264 * If doit is 0, the call is to check whether this option is
265 * potentially a speed value.
268 setspeed(arg, argv, doit)
276 spd = strtol(arg, &ptr, 0);
277 if (ptr == arg || *ptr != 0 || spd == 0)
281 slprintf(speed_str, sizeof(speed_str), "%d", spd);
288 * setdevname - Set the device name.
289 * If doit is 0, the call is to check whether this option is
290 * potentially a device name.
293 setdevname(cp, argv, doit)
299 char dev[MAXPATHLEN];
305 strlcpy(dev, "/dev/", sizeof(dev));
306 strlcat(dev, cp, sizeof(dev));
311 * Check if there is a character device by this name.
313 if (stat(cp, &statbuf) < 0) {
315 return errno != ENOENT;
316 option_error("Couldn't stat %s: %m", cp);
319 if (!S_ISCHR(statbuf.st_mode)) {
321 option_error("%s is not a character device", cp);
326 strlcpy(devnam, cp, sizeof(devnam));
338 lcp_wantoptions[0].asyncmap |= 0x000A0000; /* escape ^S and ^Q */
339 lcp_wantoptions[0].neg_asyncmap = 1;
346 * setescape - add chars to the set we escape on transmission.
358 n = strtol(p, &endp, 16);
360 option_error("escape parameter contains invalid hex number '%s'",
365 if (n < 0 || n == 0x5E || n > 0xFF) {
366 option_error("can't escape character 0x%x", n);
369 xmit_accm[n >> 5] |= 1 << (n & 0x1F);
370 while (*p == ',' || *p == ' ')
373 lcp_allowoptions[0].asyncmap = xmit_accm[0];
378 printescape(opt, printer, arg)
380 void (*printer) __P((void *, char *, ...));
386 for (n = 0; n < 256; ++n) {
388 n += 2; /* skip 7d, 7e */
389 if (xmit_accm[n >> 5] & (1 << (n & 0x1f))) {
394 printer(arg, "%x", n);
398 printer(arg, "oops # nothing escaped");
402 * tty_init - do various tty-related initializations.
406 add_notifier(&pidchange, maybe_relock, 0);
407 the_channel = &tty_channel;
408 xmit_accm[3] = 0x60000000;
412 * tty_process_extra_options - work out which tty device we are using
413 * and read its options file.
415 void tty_process_extra_options()
417 using_pty = notty || ptycommand != NULL || pty_socket != NULL;
420 if (default_device) {
422 if (!isatty(0) || (p = ttyname(0)) == NULL) {
423 option_error("no device specified and stdin is not a tty");
424 exit(EXIT_OPTION_ERROR);
426 strlcpy(devnam, p, sizeof(devnam));
427 if (stat(devnam, &devstat) < 0)
428 fatal("Couldn't stat default device %s: %m", devnam);
433 * Parse the tty options file.
434 * The per-tty options file should not change
435 * ptycommand, pty_socket, notty or devnam.
436 * options_for_tty doesn't override options set on the command line,
437 * except for some privileged options.
439 if (!options_for_tty())
440 exit(EXIT_OPTION_ERROR);
444 * tty_check_options - do consistency checks on the options we were given.
452 if (demand && notty) {
453 option_error("demand-dialling is incompatible with notty");
454 exit(EXIT_OPTION_ERROR);
456 if (demand && connect_script == 0 && ptycommand == NULL
457 && pty_socket == NULL) {
458 option_error("connect script is required for demand-dialling\n");
459 exit(EXIT_OPTION_ERROR);
461 /* default holdoff to 0 if no connect script has been given */
462 if (connect_script == 0 && !holdoff_specified)
466 if (!default_device) {
467 option_error("%s option precludes specifying device name",
468 pty_socket? "socket": notty? "notty": "pty");
469 exit(EXIT_OPTION_ERROR);
471 if (ptycommand != NULL && notty) {
472 option_error("pty option is incompatible with notty option");
473 exit(EXIT_OPTION_ERROR);
475 if (pty_socket != NULL && (ptycommand != NULL || notty)) {
476 option_error("socket option is incompatible with pty and notty");
477 exit(EXIT_OPTION_ERROR);
479 default_device = notty;
482 if (notty && log_to_fd <= 1)
486 * If the user has specified a device which is the same as
487 * the one on stdin, pretend they didn't specify any.
488 * If the device is already open read/write on stdin,
489 * we assume we don't need to lock it, and we can open it
492 if (fstat(0, &statbuf) >= 0 && S_ISCHR(statbuf.st_mode)
493 && statbuf.st_rdev == devstat.st_rdev) {
495 fdflags = fcntl(0, F_GETFL);
496 if (fdflags != -1 && (fdflags & O_ACCMODE) == O_RDWR)
504 * Don't send log messages to the serial port, it tends to
505 * confuse the peer. :-)
507 if (log_to_fd >= 0 && fstat(log_to_fd, &statbuf) >= 0
508 && S_ISCHR(statbuf.st_mode) && statbuf.st_rdev == devstat.st_rdev)
513 * connect_tty - get the serial port ready to start doing PPP.
514 * That is, open the serial port, set its speed and mode, and run
515 * the connector and/or welcomer.
527 * Get a pty master/slave pair if the pty, notty, socket,
528 * or record options were specified.
530 strlcpy(ppp_devnam, devnam, sizeof(ppp_devnam));
534 if (using_pty || record_file != NULL) {
535 if (!get_pty(&pty_master, &pty_slave, ppp_devnam, uid)) {
536 error("Couldn't allocate pseudo-tty");
537 status = EXIT_FATAL_ERROR;
540 set_up_tty(pty_slave, 1);
544 * Lock the device if we've been asked to.
546 status = EXIT_LOCK_FAILED;
547 if (lockflag && !privopen) {
548 if (lock(devnam) < 0)
554 * Open the serial device and set it up to be the ppp interface.
555 * First we open it in non-blocking mode so we can set the
556 * various termios flags appropriately. If we aren't dialling
557 * out and we want to use the modem lines, we reopen it later
558 * in order to wait for the carrier detect signal from the modem.
561 connector = doing_callback? callback_script: connect_script;
562 if (devnam[0] != 0) {
564 /* If the user specified the device name, become the
565 user before opening it. */
568 prio = privopen? OPRIO_ROOT: tty_options[0].priority;
569 if (prio < OPRIO_ROOT && seteuid(uid) == -1) {
570 error("Unable to drop privileges before opening %s: %m\n",
572 status = EXIT_OPEN_FAILED;
575 real_ttyfd = open(devnam, O_NONBLOCK | O_RDWR, 0);
577 if (prio < OPRIO_ROOT && seteuid(0) == -1)
578 fatal("Unable to regain privileges");
583 error("Failed to open %s: %m", devnam);
584 status = EXIT_OPEN_FAILED;
586 if (!persist || err != EINTR)
590 if ((fdflags = fcntl(ttyfd, F_GETFL)) == -1
591 || fcntl(ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
592 warn("Couldn't reset non-blocking mode on device: %m");
596 * Linux 2.4 and above blocks normal writes to the tty
597 * when it is in PPP line discipline, so this isn't needed.
600 * Do the equivalent of `mesg n' to stop broadcast messages.
602 if (fstat(ttyfd, &statbuf) < 0
603 || fchmod(ttyfd, statbuf.st_mode & ~(S_IWGRP | S_IWOTH)) < 0) {
604 warn("Couldn't restrict write permissions to %s: %m", devnam);
606 tty_mode = statbuf.st_mode;
607 #endif /* __linux__ */
610 * Set line speed, flow control, etc.
611 * If we have a non-null connection or initializer script,
612 * on most systems we set CLOCAL for now so that we can talk
613 * to the modem before carrier comes up. But this has the
614 * side effect that we might miss it if CD drops before we
615 * get to clear CLOCAL below. On systems where we can talk
616 * successfully to the modem with CLOCAL clear and CD down,
617 * we could clear CLOCAL at this point.
619 set_up_tty(ttyfd, ((connector != NULL && connector[0] != 0)
620 || initializer != NULL));
624 * If the pty, socket, notty and/or record option was specified,
625 * start up the character shunt now.
627 status = EXIT_PTYCMD_FAILED;
628 if (ptycommand != NULL) {
629 if (record_file != NULL) {
630 int ipipe[2], opipe[2], ok;
632 if (pipe(ipipe) < 0 || pipe(opipe) < 0)
633 fatal("Couldn't create pipes for record option: %m");
635 /* don't leak these to the ptycommand */
636 (void) fcntl(ipipe[0], F_SETFD, FD_CLOEXEC);
637 (void) fcntl(opipe[1], F_SETFD, FD_CLOEXEC);
639 ok = device_script(ptycommand, opipe[0], ipipe[1], 1) == 0
640 && start_charshunt(ipipe[0], opipe[1]);
648 if (device_script(ptycommand, pty_master, pty_master, 1) < 0)
651 } else if (pty_socket != NULL) {
652 int fd = open_socket(pty_socket);
655 if (!start_charshunt(fd, fd))
659 if (!start_charshunt(0, 1))
667 } else if (record_file != NULL) {
669 if (!start_charshunt(fd, fd))
673 if (using_pty || record_file != NULL) {
679 /* run connection script */
680 if ((connector && connector[0]) || initializer) {
681 if (real_ttyfd != -1) {
682 /* XXX do this if doing_callback == CALLBACK_DIALIN? */
683 if (!default_device && modem) {
684 setdtr(real_ttyfd, 0); /* in case modem is off hook */
686 setdtr(real_ttyfd, 1);
690 if (initializer && initializer[0]) {
691 if (device_script(initializer, ttyfd, ttyfd, 0) < 0) {
692 error("Initializer script failed");
693 status = EXIT_INIT_FAILED;
700 info("Serial port initialized.");
703 if (connector && connector[0]) {
704 if (device_script(connector, ttyfd, ttyfd, 0) < 0) {
705 error("Connect script failed");
706 status = EXIT_CONNECT_FAILED;
713 info("Serial connection established.");
716 /* set line speed, flow control, etc.;
717 clear CLOCAL if modem option */
718 if (real_ttyfd != -1)
719 set_up_tty(real_ttyfd, 0);
721 if (doing_callback == CALLBACK_DIALIN)
725 /* reopen tty if necessary to wait for carrier */
726 if (connector == NULL && modem && devnam[0] != 0) {
729 if ((i = open(devnam, O_RDWR)) >= 0)
731 if (errno != EINTR) {
732 error("Failed to reopen %s: %m", devnam);
733 status = EXIT_OPEN_FAILED;
735 if (!persist || errno != EINTR || hungup || got_sigterm)
741 slprintf(numbuf, sizeof(numbuf), "%d", baud_rate);
742 script_setenv("SPEED", numbuf, 0);
744 /* run welcome script, if any */
745 if (welcomer && welcomer[0]) {
746 if (device_script(welcomer, ttyfd, ttyfd, 0) < 0)
747 warn("Welcome script failed");
751 * If we are initiating this connection, wait for a short
752 * time for something from the peer. This can avoid bouncing
753 * our packets off his tty before he has it set up.
755 if (connector != NULL || ptycommand != NULL || pty_socket != NULL)
756 listen_time = connect_delay;
762 tcflush(real_ttyfd, TCIOFLUSH);
764 if (pty_master >= 0) {
775 void disconnect_tty()
777 if (disconnect_script == NULL || hungup)
780 set_up_tty(real_ttyfd, 1);
781 if (device_script(disconnect_script, ttyfd, ttyfd, 0) < 0) {
782 warn("disconnect script failed");
784 info("Serial link disconnected.");
786 stop_charshunt(NULL, 0);
793 if (real_ttyfd >= 0) {
797 /* N.B. ttyfd will == either pty_slave or real_ttyfd */
812 * tty_do_send_config - set transmit-side PPP configuration.
813 * We set the extended transmit ACCM here as well.
816 tty_do_send_config(mtu, accm, pcomp, accomp)
821 tty_set_xaccm(xmit_accm);
822 tty_send_config(mtu, accm, pcomp, accomp);
826 * finish_tty - restore the terminal device to its original settings
831 /* drop dtr to hang up */
832 if (!default_device && modem) {
833 setdtr(real_ttyfd, 0);
835 * This sleep is in case the serial port has CLOCAL set by default,
836 * and consequently will reassert DTR when we close the device.
841 restore_tty(real_ttyfd);
844 if (tty_mode != (mode_t) -1) {
845 if (fchmod(real_ttyfd, tty_mode) != 0)
846 error("Couldn't restore tty permissions");
848 #endif /* __linux__ */
855 * maybe_relock - our PID has changed, maybe update the lock file.
858 maybe_relock(arg, pid)
867 * open_socket - establish a stream socket connection to the nominated
874 char *sep, *endp = NULL;
877 struct hostent *hent;
878 struct sockaddr_in sad;
880 /* parse host:port and resolve host to an IP address */
881 sep = strchr(dest, ':');
883 port = strtol(sep+1, &endp, 10);
884 if (port < 0 || endp == sep+1 || sep == dest) {
885 error("Can't parse host:port for socket destination");
889 host = inet_addr(dest);
890 if (host == (u_int32_t) -1) {
891 hent = gethostbyname(dest);
893 error("%s: unknown host in socket option", dest);
897 host = *(u_int32_t *)(hent->h_addr_list[0]);
901 /* get a socket and connect it to the other end */
902 sock = socket(PF_INET, SOCK_STREAM, 0);
904 error("Can't create socket: %m");
907 memset(&sad, 0, sizeof(sad));
908 sad.sin_family = AF_INET;
909 sad.sin_port = htons(port);
910 sad.sin_addr.s_addr = host;
911 if (connect(sock, (struct sockaddr *)&sad, sizeof(sad)) < 0) {
912 error("Can't connect to %s: %m", dest);
922 * start_charshunt - create a child process to run the character shunt.
925 start_charshunt(ifd, ofd)
930 cpid = safe_fork(ifd, ofd, (log_to_fd >= 0? log_to_fd: 2));
932 error("Can't fork process for character shunt: %m");
940 else if (log_to_fd >= 0)
945 fatal("setuid failed");
946 charshunt(0, 1, record_file);
949 charshunt_pid = cpid;
950 record_child(cpid, "pppd (charshunt)", charshunt_done, NULL, 1);
962 stop_charshunt(arg, sig)
967 kill(charshunt_pid, (sig == SIGINT? sig: SIGTERM));
971 * charshunt - the character shunt, which passes characters between
972 * the pty master side and the serial port (or stdin/stdout).
973 * This runs as the user (not as root).
974 * (We assume ofd >= ifd which is true the way this gets called. :-).
977 charshunt(ifd, ofd, record_file)
982 fd_set ready, writey;
983 u_char *ibufp, *obufp;
986 int pty_readable, stdin_readable;
987 struct timeval lasttime;
988 FILE *recordf = NULL;
989 int ilevel, olevel, max_level;
990 struct timeval levelt, tout, *top;
991 extern u_char inpacket_buf[];
994 * Reset signal handlers.
996 signal(SIGHUP, SIG_IGN); /* Hangup */
997 signal(SIGINT, SIG_DFL); /* Interrupt */
998 signal(SIGTERM, SIG_DFL); /* Terminate */
999 signal(SIGCHLD, SIG_DFL);
1000 signal(SIGUSR1, SIG_DFL);
1001 signal(SIGUSR2, SIG_DFL);
1002 signal(SIGABRT, SIG_DFL);
1003 signal(SIGALRM, SIG_DFL);
1004 signal(SIGFPE, SIG_DFL);
1005 signal(SIGILL, SIG_DFL);
1006 signal(SIGPIPE, SIG_DFL);
1007 signal(SIGQUIT, SIG_DFL);
1008 signal(SIGSEGV, SIG_DFL);
1010 signal(SIGBUS, SIG_DFL);
1013 signal(SIGEMT, SIG_DFL);
1016 signal(SIGPOLL, SIG_DFL);
1019 signal(SIGPROF, SIG_DFL);
1022 signal(SIGSYS, SIG_DFL);
1025 signal(SIGTRAP, SIG_DFL);
1028 signal(SIGVTALRM, SIG_DFL);
1031 signal(SIGXCPU, SIG_DFL);
1034 signal(SIGXFSZ, SIG_DFL);
1038 * Check that the fds won't overrun the fd_sets
1040 if (ifd >= FD_SETSIZE || ofd >= FD_SETSIZE || pty_master >= FD_SETSIZE)
1041 fatal("internal error: file descriptor too large (%d, %d, %d)",
1042 ifd, ofd, pty_master);
1045 * Open the record file if required.
1047 if (record_file != NULL) {
1048 recordf = fopen(record_file, "a");
1049 if (recordf == NULL)
1050 error("Couldn't create record file %s: %m", record_file);
1053 /* set all the fds to non-blocking mode */
1054 flags = fcntl(pty_master, F_GETFL);
1056 || fcntl(pty_master, F_SETFL, flags | O_NONBLOCK) == -1)
1057 warn("couldn't set pty master to nonblock: %m");
1058 flags = fcntl(ifd, F_GETFL);
1060 || fcntl(ifd, F_SETFL, flags | O_NONBLOCK) == -1)
1061 warn("couldn't set %s to nonblock: %m", (ifd==0? "stdin": "tty"));
1063 flags = fcntl(ofd, F_GETFL);
1065 || fcntl(ofd, F_SETFL, flags | O_NONBLOCK) == -1)
1066 warn("couldn't set stdout to nonblock: %m");
1070 ibufp = obufp = NULL;
1071 pty_readable = stdin_readable = 1;
1073 ilevel = olevel = 0;
1074 gettimeofday(&levelt, NULL);
1075 if (max_data_rate) {
1076 max_level = max_data_rate / 10;
1077 if (max_level < 100)
1080 max_level = PPP_MRU + PPP_HDRLEN + 1;
1082 nfds = (ofd > pty_master? ofd: pty_master) + 1;
1083 if (recordf != NULL) {
1084 gettimeofday(&lasttime, NULL);
1085 putc(7, recordf); /* put start marker */
1086 putc(lasttime.tv_sec >> 24, recordf);
1087 putc(lasttime.tv_sec >> 16, recordf);
1088 putc(lasttime.tv_sec >> 8, recordf);
1089 putc(lasttime.tv_sec, recordf);
1090 lasttime.tv_usec = 0;
1093 while (nibuf != 0 || nobuf != 0 || pty_readable || stdin_readable) {
1096 tout.tv_usec = 10000;
1100 if (ilevel >= max_level)
1103 FD_SET(pty_master, &writey);
1104 } else if (stdin_readable)
1105 FD_SET(ifd, &ready);
1107 if (olevel >= max_level)
1110 FD_SET(ofd, &writey);
1111 } else if (pty_readable)
1112 FD_SET(pty_master, &ready);
1113 if (select(nfds, &ready, &writey, NULL, top) < 0) {
1118 if (max_data_rate) {
1123 gettimeofday(&now, NULL);
1124 dt = (now.tv_sec - levelt.tv_sec
1125 + (now.tv_usec - levelt.tv_usec) / 1e6);
1126 nbt = (int)(dt * max_data_rate);
1127 ilevel = (nbt < 0 || nbt > ilevel)? 0: ilevel - nbt;
1128 olevel = (nbt < 0 || nbt > olevel)? 0: olevel - nbt;
1131 ilevel = olevel = 0;
1132 if (FD_ISSET(ifd, &ready)) {
1133 ibufp = inpacket_buf;
1134 nibuf = read(ifd, ibufp, PPP_MRU + PPP_HDRLEN);
1135 if (nibuf < 0 && errno == EIO)
1138 if (!(errno == EINTR || errno == EAGAIN)) {
1139 error("Error reading standard input: %m");
1143 } else if (nibuf == 0) {
1144 /* end of file from stdin */
1147 if (!record_write(recordf, 4, NULL, 0, &lasttime))
1150 FD_SET(pty_master, &writey);
1152 if (!record_write(recordf, 2, ibufp, nibuf, &lasttime))
1156 if (FD_ISSET(pty_master, &ready)) {
1157 obufp = outpacket_buf;
1158 nobuf = read(pty_master, obufp, PPP_MRU + PPP_HDRLEN);
1159 if (nobuf < 0 && errno == EIO)
1162 if (!(errno == EINTR || errno == EAGAIN)) {
1163 error("Error reading pseudo-tty master: %m");
1167 } else if (nobuf == 0) {
1168 /* end of file from the pty - slave side has closed */
1170 stdin_readable = 0; /* pty is not writable now */
1174 if (!record_write(recordf, 3, NULL, 0, &lasttime))
1177 FD_SET(ofd, &writey);
1179 if (!record_write(recordf, 1, obufp, nobuf, &lasttime))
1182 } else if (!stdin_readable)
1184 if (FD_ISSET(ofd, &writey)) {
1186 if (olevel + n > max_level)
1187 n = max_level - olevel;
1188 n = write(ofd, obufp, n);
1193 } else if (errno != EAGAIN && errno != EINTR) {
1194 error("Error writing standard output: %m");
1203 if (FD_ISSET(pty_master, &writey)) {
1205 if (ilevel + n > max_level)
1206 n = max_level - ilevel;
1207 n = write(pty_master, ibufp, n);
1212 } else if (errno != EAGAIN && errno != EINTR) {
1213 error("Error writing pseudo-tty master: %m");
1227 record_write(f, code, buf, nb, tp)
1237 gettimeofday(&now, NULL);
1238 now.tv_usec /= 100000; /* actually 1/10 s, not usec now */
1239 diff = (now.tv_sec - tp->tv_sec) * 10 + (now.tv_usec - tp->tv_usec);
1243 putc(diff >> 24, f);
1244 putc(diff >> 16, f);
1257 fwrite(buf, nb, 1, f);
1261 error("Error writing record file: %m");