/*
 * modem.c - Modem control functions.
 *
 * Copyright (c) 1994, 1995, 1996 Eric Schenk.
 * Copyright (c) 1999 Mike Jagdis.
 * All rights reserved. Please see the file LICENSE which should be
 * distributed with this software for terms of use.
 *
 * Portions of this code were derived from the code for pppd copyright
 * (c) 1989 Carnegie Mellon University. The copyright notice on this code
 * is reproduced below.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by Carnegie Mellon University.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include "diald.h"

static char *lock_file = 0;
static int rotate_offset = 0;

char *current_dev = 0;
int current_mode;
int current_slip_encap;

/* local variables */

static struct termios inittermios;      /* Initial TTY termios */
static int restore_term = 0;

#if B9600 == 9600
/*
 * XXX assume speed_t values numerically equal bits per second
 * (so we can ask for any speed).
 */
#define translate_speed(bps)	(bps)

#else
/*
 * List of valid speeds.
 */
struct speed {
    int speed_int, speed_val;
} speeds[] = {
#ifdef B50
    { 50, B50 },
#endif
#ifdef B75
    { 75, B75 },
#endif
#ifdef B110
    { 110, B110 },
#endif
#ifdef B134
    { 134, B134 },
#endif
#ifdef B150
    { 150, B150 },
#endif
#ifdef B200
    { 200, B200 },
#endif
#ifdef B300
    { 300, B300 },
#endif
#ifdef B600
    { 600, B600 },
#endif
#ifdef B1200
    { 1200, B1200 },
#endif
#ifdef B1800
    { 1800, B1800 },
#endif
#ifdef B2000
    { 2000, B2000 },
#endif
#ifdef B2400
    { 2400, B2400 },
#endif
#ifdef B3600
    { 3600, B3600 },
#endif
#ifdef B4800
    { 4800, B4800 },
#endif
#ifdef B7200
    { 7200, B7200 },
#endif
#ifdef B9600
    { 9600, B9600 },
#endif
#ifdef B19200
    { 19200, B19200 },
#endif
#ifdef B38400
    { 38400, B38400 },
#endif
#ifdef EXTA
    { 19200, EXTA },
#endif
#ifdef EXTB
    { 38400, EXTB },
#endif
#ifdef B57600
    { 57600, B57600 },
#endif
#ifdef B115200
    { 115200, B115200 },
#endif
#ifdef B230400
    { 230400, B230400 },
#endif
#ifdef B460800
    { 460800, B460800 },
#endif
    { 0, 0 }
};

/*
 * Translate from bits/second to a speed_t.
 */
int translate_speed(int bps)
{
    struct speed *speedp;

    if (bps == 0)
	return 0;
    for (speedp = speeds; speedp->speed_int; speedp++)
	if (bps == speedp->speed_int)
	    return speedp->speed_val;
    mon_syslog(LOG_WARNING, "speed %d not supported", bps);
    return 0;
}
#endif

/*
 * set_up_tty: Set up the serial port on `fd' for 8 bits, no parity,
 * at the requested speed, etc.  If `local' is true, set CLOCAL
 * regardless of whether the modem option was specified.
 */
void set_up_tty(int fd, int local, int spd)
{
    int speed, i;
    struct termios tios;

    if (tcgetattr(fd, &tios) < 0) {
	mon_syslog(LOG_ERR, "could not get initial terminal attributes: %m");
    }

    tios.c_cflag = CS8 | CREAD | HUPCL;
    if (local || !modem) tios.c_cflag |= CLOCAL;
    if (crtscts == 1) tios.c_cflag |= CRTSCTS;
    tios.c_iflag = IGNBRK | IGNPAR;
    tios.c_oflag = 0;
    tios.c_lflag = 0;
    for (i = 0; i < NCCS; i++)
	tios.c_cc[i] = 0;
    tios.c_cc[VMIN] = 1;
    tios.c_cc[VTIME] = 0;

    speed = translate_speed(spd);
    if (speed) {
	cfsetospeed(&tios, speed);
	cfsetispeed(&tios, speed);
    } else {
	speed = cfgetospeed(&tios);
    }

    if (tcsetattr(fd, TCSAFLUSH, &tios) < 0) {
	mon_syslog(LOG_ERR, "failed to set terminal attributes: %m");
    }
}

/*
 * setdtr - control the DTR line on the serial port.
 * This is called from die(), so it shouldn't call die().
 */
void setdtr(int fd, int on)
{
    int modembits = TIOCM_DTR;

    ioctl(fd, (on? TIOCMBIS: TIOCMBIC), &modembits);
}


/*
 * Open up a modem and set up the desired parameters.
 */
int open_modem()
{
    int i;

    /*
     * Open the serial device and set it up.
     */

    modem_hup = 0;
    modem_fd = -1;
    dial_status = 0;

    /* If this is a request for diald to take over management of an
     * interface that we didn't bring up ourselves there is little
     * to do here except note what we are taking on.
     */
    if (req_pid) {
	current_dev = req_dev;
	use_req=1;

	/* FIXME: If we are locking devices and the requested device
	 * is not already locked we should probably lock it to prevent
	 * anyone else trying it. This is a particular problem with
	 * non-modem devices such as isdn? and ippp?.
	 *   Possibly we should also inherit existing locks?
	 */

	modem_fd = open(current_dev[0] == '/' ? current_dev : "/dev/null",
			O_RDWR | O_NDELAY);
	if (modem_fd < 0) {
	    mon_syslog(LOG_ERR, "Can't open requested device '%s'", req_dev);
	    if (current_dev[0] != '/')
		req_pid = 0;
	    else {
	    	killpg(req_pid, SIGKILL);
	    	kill(req_pid, SIGKILL);
	    }
	    dial_status = -1;
	    return 1;
	}
	if (lock_dev) lock_file = lock(current_dev);
    } else {
	for (i = 0; i < device_count; i++) {
	    current_dev = devices[(i+rotate_offset)%device_count];

	    if (lock_dev && !(lock_file = lock(current_dev)))
		continue;

	    /* OK. Locked one, try to open it */
	    modem_fd = open(current_dev[0] == '/' ? current_dev : "/dev/null",
			    O_RDWR | O_NDELAY);
	    if (modem_fd >= 0)
		break;

	    /* That didn't work, get rid of the lock */
	    mon_syslog(LOG_ERR,"Error opening device %s: %m",current_dev);
	    if (lock_dev) unlock(lock_file);
	}
	if (modem_fd < 0) {
	    mon_syslog(LOG_WARNING,"No devices free to call out on.");
	    current_dev = 0;
	    dial_status = -1;
	    return 2;
	}

	if (rotate_devices)
	    rotate_offset = (rotate_offset+1)%device_count;

	current_dev = strdup(current_dev);
    }
    fcntl(modem_fd, F_SETFD, FD_CLOEXEC);

    if (current_dev[0] != '/')
	current_mode = MODE_DEV;
    else {
	current_mode = mode;
	current_slip_encap = slip_encap;
    }

    if (current_mode == MODE_DEV) {
	/* If we have a connector we may need to run it to set up the
	 * real interface.
	 */
	if (!req_pid && connector)
		dial_pid = run_shell(SHELL_NOWAIT,
				"connector", connector, modem_fd);
	req_pid = 0;
	return 0;
    }


    /* set device to be controlling tty */
    /* FIXME: we should not die here. If we go round again we may
     * be able to use the next device in the list.
     */
    /* If this is outgoing this should have become our controlling
     * tty when we opened it. If it is incoming it belongs to
     * another session so we have to steal it.
     */
    if (ioctl(modem_fd, TIOCSCTTY, 1) < 0) {
	mon_syslog(LOG_ERR, "failed to set modem to controlling tty: %m");
	die(1);
    }

    if (tcsetpgrp(modem_fd, getpgrp()) < 0) {
	mon_syslog(LOG_ERR, "open: failed to set tty process group: %m");
	die(1);
    }

    /* Get rid of any initial line noise */
    tcflush(modem_fd, TCIOFLUSH);

    if (tcgetattr(modem_fd, &inittermios) < 0) {
	mon_syslog(LOG_ERR, "failed to get initial modem terminal attributes: %m");
    }

    /* So we don't try to restore if we die before this */
    restore_term = 1;

    /* Clear the NDELAY flag now */
    if (fcntl(modem_fd,F_SETFL,fcntl(modem_fd,F_GETFL)&~(O_NDELAY)) < 0)
	mon_syslog(LOG_ERR, "failed to clear O_NDELAY flag: %m"), die(1);

    if (!req_pid) {
	int line_disc;

	/* hang up and then start again */
	set_up_tty(modem_fd, 1, inspeed);
	if (ioctl(modem_fd, TIOCGETD, &line_disc) < 0 || line_disc != N_TTY) {
	    line_disc = N_TTY;
	    ioctl(modem_fd, TIOCSETD, &line_disc);
	}
	set_up_tty(modem_fd, 1, 0);
	sleep(1);
	set_up_tty(modem_fd, 1, inspeed);

	/* Get rid of any initial line noise after the hangup */
	tcflush(modem_fd, TCIOFLUSH);
	dial_pid = run_shell(SHELL_NOWAIT, "connector", connector, modem_fd);
    } else {
	/* someone else opened the line, we just set the mode */
	set_up_tty(modem_fd, 0, inspeed);
    }
    return 0;
}

/*
 * Reopen up a modem that closed on a sighup and set up the desired parameters.
 */
void reopen_modem()
{
    if (current_mode == MODE_DEV)
	return;

    if(debug&DEBUG_VERBOSE)
	mon_syslog(LOG_INFO,"Reopening modem device");

    close(modem_fd);
    sleep(1);
    if ((modem_fd = open(current_dev, O_RDWR | O_NDELAY)) < 0) {
	mon_syslog(LOG_ERR,"Can't reopen device '%s'",current_dev);
    } else {
	/* set device to be controlling tty */
	if (ioctl(modem_fd, TIOCSCTTY, 1) < 0) {
	    mon_syslog(LOG_ERR, "reopen: failed to set modem to controlling tty: %m");
	    die(1);
	}

	if (tcsetpgrp(modem_fd, getpgrp()) < 0) {
	    mon_syslog(LOG_ERR, "reopen: failed to set process group: %m");
	    die(1);
	}

	set_up_tty(modem_fd, 1, inspeed);
	/* Clear the NDELAY flag now */
	if (fcntl(modem_fd,F_SETFL,fcntl(modem_fd,F_GETFL)&~(O_NDELAY)) < 0)
	    mon_syslog(LOG_ERR, "failed to clear O_NDELAY flag: %m"), die(1);
    }
}

void finish_dial()
{
    if (current_mode == MODE_DEV)
	return;

    if (!req_pid) {
	if (tcsetpgrp(modem_fd, getpgrp()) < 0)
	    mon_syslog(LOG_ERR, "finish: failed to set pgrp: %m");
        set_up_tty(modem_fd, 0, inspeed);
    }
}

/*
 * Close the modem, making sure it hangs up properly!
 */
void close_modem()
{
    if (current_dev && debug&DEBUG_VERBOSE)
        mon_syslog(LOG_INFO,"Closing %s", current_dev);

    if (current_dev)
	free(current_dev);
    current_dev = 0;
    if (modem_fd < 0)
 	return;

    if (current_mode != MODE_DEV) {
	tcsetpgrp(modem_fd, getpgrp());

	/* Get rid of what ever might be waiting to go out still */
	tcflush(modem_fd, TCIOFLUSH);

	/*
	 * Restore the initial termio settings.
	 */

	if (restore_term) {
	    tcsetattr(modem_fd, TCSANOW, &inittermios);
	}

	/*
	 * Hang up the modem up by dropping the DTR.
	 * We do this because the initial termio settings
	 * may not have set HUPCL. This forces the issue.
	 * We need the sleep to give the modem a chance to hang
	 * up before we get another program asserting the DTR.
	 */
	setdtr(modem_fd, 0);
	sleep(1);
    }

    close(modem_fd);
    modem_fd = -1;

    if (use_req) {
	if (req_pid) {
	    if (debug&DEBUG_VERBOSE)
		mon_syslog(LOG_INFO, "Killing requesting shell pid %d",req_pid);
	    killpg(req_pid, SIGKILL);
	    kill(req_pid, SIGKILL);
	    req_pid = 0;
	}
    }
    if (lock_file) {
	unlock(lock_file);
	lock_file = NULL;
    }
}