tty.c

自己精简过的PPPD代码。在嵌入中应用可以更好的发挥。比原先的小了很多

/*
 * tty.c - code for handling serial ports in pppd.
 *
 * Copyright (C) 2000-2004 Paul Mackerras. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. The name(s) of the authors of this software must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission.
 *
 * 3. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Paul Mackerras
 *     <[e-mail]>".
 *
 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Portions derived from main.c, which is:
 *
 * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The name "Carnegie Mellon University" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For permission or any legal
 *    details, please contact
 *      Office of Technology Transfer
 *      Carnegie Mellon University
 *      5000 Forbes Avenue
 *      Pittsburgh, PA  15213-3890
 *      [phone], fax: [phone]
 *      [e-mail]
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Computing Services
 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
 *
 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#define RCSID	"$Id: tty.c,v 1.25 2006/06/04 07:04:57 paulus Exp $"

#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include <syslog.h>
#include <netdb.h>
#include <utmp.h>
#include <pwd.h>
#include <setjmp.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "pppd.h"
#include "fsm.h"
#include "lcp.h"

void tty_process_extra_options __P((void));
void tty_check_options __P((void));
int  connect_tty __P((void));
void disconnect_tty __P((void));
void tty_close_fds __P((void));
void cleanup_tty __P((void));
void tty_do_send_config __P((int, u_int32_t, int, int));

static int setdevname __P((char *, char **, int));
static int setspeed __P((char *, char **, int));
static int setxonxoff __P((char **));
static int setescape __P((char **));
static void printescape __P((option_t *, void (*)(void *, char *,...),void *));
static void finish_tty __P((void));
static int start_charshunt __P((int, int));
static void stop_charshunt __P((void *, int));
static void charshunt_done __P((void *));
static void charshunt __P((int, int, char *));
static int record_write __P((FILE *, int code, u_char *buf, int nb,
			     struct timeval *));
static int open_socket __P((char *));
static void maybe_relock __P((void *, int));

static int pty_master;		/* fd for master side of pty */
static int pty_slave;		/* fd for slave side of pty */
static int real_ttyfd;		/* fd for actual serial port (not pty) */
static int ttyfd;		/* Serial port file descriptor */
static char speed_str[16];	/* Serial port speed as string */

mode_t tty_mode = (mode_t)-1;	/* Original access permissions to tty */
int baud_rate;			/* Actual bits/second for serial device */
char *callback_script;		/* script for doing callback */
int charshunt_pid;		/* Process ID for charshunt */
int locked;			/* lock() has succeeded */
struct stat devstat;		/* result of stat() on devnam */

/* option variables */
int	crtscts = 0;		/* Use hardware flow control */
bool	modem = 1;		/* Use modem control lines */
int	inspeed = 0;		/* Input/Output speed requested */
bool	lockflag = 0;		/* Create lock file to lock the serial dev */
char	*initializer = NULL;	/* Script to initialize physical link */
char	*connect_script = NULL;	/* Script to establish physical link */
char	*disconnect_script = NULL; /* Script to disestablish physical link */
char	*welcomer = NULL;	/* Script to run after phys link estab. */
char	*ptycommand = NULL;	/* Command to run on other side of pty */
bool	notty = 0;		/* Stdin/out is not a tty */
char	*record_file = NULL;	/* File to record chars sent/received */
int	max_data_rate;		/* max bytes/sec through charshunt */
bool	sync_serial = 0;	/* Device is synchronous serial device */
char	*pty_socket = NULL;	/* Socket to connect to pty */
int	using_pty = 0;		/* we're allocating a pty as the device */

extern uid_t uid;
extern int kill_link;
extern int asked_to_quit;
extern int got_sigterm;

/* XXX */
extern int privopen;		/* don't lock, open device as root */

u_int32_t xmit_accm[8];		/* extended transmit ACCM */

/* option descriptors */
option_t tty_options[] = {
    /* device name must be first, or change connect_tty() below! */
    { "device name", o_wild, (void *) &setdevname,
      "Serial port device name",
      OPT_DEVNAM | OPT_PRIVFIX | OPT_NOARG  | OPT_A2STRVAL | OPT_STATIC,
      devnam},

    { "tty speed", o_wild, (void *) &setspeed,
      "Baud rate for serial port",
      OPT_PRIO | OPT_NOARG | OPT_A2STRVAL | OPT_STATIC, speed_str },

    { "lock", o_bool, &lockflag,
      "Lock serial device with UUCP-style lock file", OPT_PRIO | 1 },
    { "nolock", o_bool, &lockflag,
      "Don't lock serial device", OPT_PRIOSUB | OPT_PRIV },

    { "init", o_string, &initializer,
      "A program to initialize the device", OPT_PRIO | OPT_PRIVFIX },

    { "connect", o_string, &connect_script,
      "A program to set up a connection", OPT_PRIO | OPT_PRIVFIX },

    { "disconnect", o_string, &disconnect_script,
      "Program to disconnect serial device", OPT_PRIO | OPT_PRIVFIX },

    { "welcome", o_string, &welcomer,
      "Script to welcome client", OPT_PRIO | OPT_PRIVFIX },

    { "pty", o_string, &ptycommand,
      "Script to run on pseudo-tty master side",
      OPT_PRIO | OPT_PRIVFIX | OPT_DEVNAM },

    { "notty", o_bool, &notty,
      "Input/output is not a tty", OPT_DEVNAM | 1 },

    { "socket", o_string, &pty_socket,
      "Send and receive over socket, arg is host:port",
      OPT_PRIO | OPT_DEVNAM },

    { "record", o_string, &record_file,
      "Record characters sent/received to file", OPT_PRIO },

    { "crtscts", o_int, &crtscts,
      "Set hardware (RTS/CTS) flow control",
      OPT_PRIO | OPT_NOARG | OPT_VAL(1) },
    { "cdtrcts", o_int, &crtscts,
      "Set alternate hardware (DTR/CTS) flow control",
      OPT_PRIOSUB | OPT_NOARG | OPT_VAL(2) },
    { "nocrtscts", o_int, &crtscts,
      "Disable hardware flow control",
      OPT_PRIOSUB | OPT_NOARG | OPT_VAL(-1) },
    { "-crtscts", o_int, &crtscts,
      "Disable hardware flow control",
      OPT_PRIOSUB | OPT_ALIAS | OPT_NOARG | OPT_VAL(-1) },
    { "nocdtrcts", o_int, &crtscts,
      "Disable hardware flow control",
      OPT_PRIOSUB | OPT_ALIAS | OPT_NOARG | OPT_VAL(-1) },
    { "xonxoff", o_special_noarg, (void *)setxonxoff,
      "Set software (XON/XOFF) flow control", OPT_PRIOSUB },

    { "modem", o_bool, &modem,
      "Use modem control lines", OPT_PRIO | 1 },
    { "local", o_bool, &modem,
      "Don't use modem control lines", OPT_PRIOSUB | 0 },

    { "sync", o_bool, &sync_serial,
      "Use synchronous HDLC serial encoding", 1 },

    { "datarate", o_int, &max_data_rate,
      "Maximum data rate in bytes/sec (with pty, notty or record option)",
      OPT_PRIO },

    { "escape", o_special, (void *)setescape,
      "List of character codes to escape on transmission",
      OPT_A2PRINTER, (void *)printescape },

    { NULL }
};


struct channel tty_channel = {
	tty_options,
	&tty_process_extra_options,
	&tty_check_options,
	&connect_tty,
	&disconnect_tty,
	&tty_establish_ppp,
	&tty_disestablish_ppp,
	&tty_do_send_config,
	&tty_recv_config,
	&cleanup_tty,
	&tty_close_fds
};

/*
 * setspeed - Set the serial port baud rate.
 * If doit is 0, the call is to check whether this option is
 * potentially a speed value.
 */
static int
setspeed(arg, argv, doit)
    char *arg;
    char **argv;
    int doit;
{
	char *ptr;
	int spd;

	spd = strtol(arg, &ptr, 0);
	if (ptr == arg || *ptr != 0 || spd == 0)
		return 0;
	if (doit) {
		inspeed = spd;
		slprintf(speed_str, sizeof(speed_str), "%d", spd);
	}
	return 1;
}


/*
 * setdevname - Set the device name.
 * If doit is 0, the call is to check whether this option is
 * potentially a device name.
 */
static int
setdevname(cp, argv, doit)
    char *cp;
    char **argv;
    int doit;
{
	struct stat statbuf;
	char dev[MAXPATHLEN];

	if (*cp == 0)
		return 0;

	if (*cp != '/') {
		strlcpy(dev, "/dev/", sizeof(dev));
		strlcat(dev, cp, sizeof(dev));
		cp = dev;
	}

	/*
	 * Check if there is a character device by this name.
	 */
	if (stat(cp, &statbuf) < 0) {
		if (!doit)
			return errno != ENOENT;
		option_error("Couldn't stat %s: %m", cp);
		return 0;
	}
	if (!S_ISCHR(statbuf.st_mode)) {
		if (doit)
			option_error("%s is not a character device", cp);
		return 0;
	}

	if (doit) {
		strlcpy(devnam, cp, sizeof(devnam));
		devstat = statbuf;
		default_device = 0;
	}
  
	return 1;
}

static int
setxonxoff(argv)
    char **argv;
{
	lcp_wantoptions[0].asyncmap |= 0x000A0000;	/* escape ^S and ^Q */
	lcp_wantoptions[0].neg_asyncmap = 1;

	crtscts = -2;
	return 1;
}

/*
 * setescape - add chars to the set we escape on transmission.
 */
static int
setescape(argv)
    char **argv;
{
    int n, ret;
    char *p, *endp;

    p = *argv;
    ret = 1;
    while (*p) {
	n = strtol(p, &endp, 16);
	if (p == endp) {
	    option_error("escape parameter contains invalid hex number '%s'",
			 p);
	    return 0;
	}
	p = endp;
	if (n < 0 || n == 0x5E || n > 0xFF) {
	    option_error("can't escape character 0x%x", n);
	    ret = 0;
	} else
	    xmit_accm[n >> 5] |= 1 << (n & 0x1F);
	while (*p == ',' || *p == ' ')
	    ++p;
    }
    lcp_allowoptions[0].asyncmap = xmit_accm[0];
    return ret;
}

static void
printescape(opt, printer, arg)
    option_t *opt;
    void (*printer) __P((void *, char *, ...));
    void *arg;
{
	int n;
	int first = 1;

	for (n = 0; n < 256; ++n) {
		if (n == 0x7d)
			n += 2;		/* skip 7d, 7e */
		if (xmit_accm[n >> 5] & (1 << (n & 0x1f))) {
			if (!first)
				printer(arg, ",");
			else
				first = 0;
			printer(arg, "%x", n);
		}
	}
	if (first)
		printer(arg, "oops # nothing escaped");
}

/*
 * tty_init - do various tty-related initializations.
 */
void tty_init()
{
    add_notifier(&pidchange, maybe_relock, 0);
    the_channel = &tty_channel;
    xmit_accm[3] = 0x60000000;
}

/*
 * tty_process_extra_options - work out which tty device we are using
 * and read its options file.
 */
void tty_process_extra_options()
{
	using_pty = notty || ptycommand != NULL || pty_socket != NULL;
	if (using_pty)
		return;
	if (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);