path: root/term-utils/agetty.c

/*
 * agetty.c - another getty program for Linux. By W. Z. Venema 1989
 *
 * Ported to Linux by Peter Orbaek <poe@daimi.aau.dk>
 * This program is freely distributable. The entire man-page used to
 * be here. Now read the real man-page agetty.8 instead.
 *
 */
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <signal.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdarg.h>
#include <ctype.h>
#include <utmp.h>
#include <getopt.h>
#include <time.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <netdb.h>

#include "strutils.h"
#include "nls.h"
#include "pathnames.h"
#include "c.h"
#include "xalloc.h"

#ifdef __linux__
#include <sys/param.h>
#define USE_SYSLOG
#endif

/* If USE_SYSLOG is undefined all diagnostics go directly to /dev/console. */

#ifdef	USE_SYSLOG
#include <syslog.h>
#endif

/*
 * Some heuristics to find out what environment we are in: if it is not
 * System V, assume it is SunOS 4.
 */
#ifdef LOGIN_PROCESS			/* defined in System V utmp.h */
#define	SYSV_STYLE			/* select System V style getty */
#endif

/*
 * Things you may want to modify.
 *
 * If ISSUE is not defined, agetty will never display the contents of the
 * /etc/issue file. You will not want to spit out large "issue" files at the
 * wrong baud rate. Relevant for System V only.
 *
 * You may disagree with the default line-editing etc. characters defined
 * below. Note, however, that DEL cannot be used for interrupt generation
 * and for line editing at the same time.
 */

#ifdef	SYSV_STYLE
#define	ISSUE "/etc/issue"		/* displayed before the login prompt */
#include <sys/utsname.h>
#endif

#define LOGIN " login: "		/* login prompt */

/* Some shorthands for control characters. */

#define CTL(x)		(x ^ 0100)	/* Assumes ASCII dialect */
#define	CR		CTL('M')	/* carriage return */
#define	NL		CTL('J')	/* line feed */
#define	BS		CTL('H')	/* back space */
#define	DEL		CTL('?')	/* delete */

/* Defaults for line-editing etc. characters; you may want to change this. */

#define DEF_ERASE	DEL		/* default erase character */
#define DEF_INTR	CTL('C')	/* default interrupt character */
#define DEF_QUIT	CTL('\\')	/* default quit char */
#define DEF_KILL	CTL('U')	/* default kill char */
#define DEF_EOF		CTL('D')	/* default EOF char */
#define DEF_EOL		0
#define DEF_SWITCH	0		/* default switch char */

#ifndef MAXHOSTNAMELEN
# ifdef HOST_NAME_MAX
#  define MAXHOSTNAMELEN HOST_NAME_MAX
# else
#  define MAXHOSTNAMELEN 64
# endif /* HOST_NAME_MAX */
#endif /* MAXHOSTNAMELEN */

/*
 * When multiple baud rates are specified on the command line, the first one
 * we will try is the first one specified.
 */
#define	FIRST_SPEED	0

/* Storage for command-line options. */

#define	MAX_SPEED	10		/* max. nr. of baud rates */

struct options {
	int     flags;			/* toggle switches, see below */
	int     timeout;			/* time-out period */
	char   *login;			/* login program */
	char   *tty;			/* name of tty */
	char   *initstring;			/* modem init string */
	char   *issue;			/* alternative issue file */
	int     numspeed;			/* number of baud rates to try */
	int     speeds[MAX_SPEED];		/* baud rates to be tried */
	int     eightbits;			/* assume 8bit-clean tty */
};

#define	F_PARSE		(1<<0)		/* process modem status messages */
#define	F_ISSUE		(1<<1)		/* display /etc/issue */
#define	F_RTSCTS	(1<<2)		/* enable RTS/CTS flow control */
#define F_LOCAL		(1<<3)		/* force local */
#define F_INITSTRING    (1<<4)		/* initstring is set */
#define F_WAITCRLF	(1<<5)		/* wait for CR or LF */
#define F_CUSTISSUE	(1<<6)		/* give alternative issue file */
#define F_NOPROMPT	(1<<7)		/* don't ask for login name! */
#define F_LCUC		(1<<8)		/* Support for *LCUC stty modes */
#define F_KEEPSPEED	(1<<9)		/* Follow baud rate from kernel */
#define F_KEEPCFLAGS	(1<<10)		/* Reuse c_cflags setup from kernel */

/* Storage for things detected while the login name was read. */

struct chardata {
	int     erase;			/* erase character */
	int     kill;			/* kill character */
	int     eol;			/* end-of-line character */
	int     parity;			/* what parity did we see */
	int     capslock;			/* upper case without lower case */
};

/* Initial values for the above. */

struct chardata init_chardata = {
	DEF_ERASE,				/* default erase character */
	DEF_KILL,				/* default kill character */
	13,					/* default eol char */
	0,					/* space parity */
	0,					/* no capslock */
};

struct Speedtab {
	long    speed;
	int     code;
};

static struct Speedtab speedtab[] = {
	{ 50, B50 },
	{ 75, B75 },
	{ 110, B110 },
	{ 134, B134 },
	{ 150, B150 },
	{ 200, B200 },
	{ 300, B300 },
	{ 600, B600 },
	{ 1200, B1200 },
	{ 1800, B1800 },
	{ 2400, B2400 },
	{ 4800, B4800 },
	{ 9600, B9600 },
#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
	{ 0, 0 },
};

#define P_(s) s
int main P_((int argc, char **argv));
void parse_args P_((int argc, char **argv, struct options *op));
void parse_speeds P_((struct options *op, char *arg));
void update_utmp P_((char *line));
void open_tty P_((char *tty, struct termios *tp, int local));
void termio_init P_((struct termios *tp, struct options *op));
void auto_baud P_((struct termios *tp));
void do_prompt P_((struct options *op, struct termios *tp));
void next_speed P_((struct termios *tp, struct options *op));
char *get_logname P_((struct options *op, struct chardata *cp, struct termios *tp));
void termio_final P_((struct options *op, struct termios *tp, struct chardata *cp));
int caps_lock P_((char *s));
int bcode P_((char *s));
void usage P_((FILE *out));
void error P_((const char *, ...));
#undef P_

/* Fake hostname for ut_host specified on command line. */
char *fakehost = NULL;

/* ... */
#ifdef DEBUGGING
#define debug(s) fprintf(dbf,s); fflush(dbf)
FILE *dbf;
#else
#define debug(s) /* nothing */
#endif /* DEBUGGING */

int main(argc, argv)
	int     argc;
	char  **argv;
{
	char   *logname = NULL;		/* login name, given to /bin/login */
	struct chardata chardata;	/* set by get_logname() */
	struct termios termios;		/* terminal mode bits */
	static struct options options = {
		F_ISSUE,		/* show /etc/issue (SYSV_STYLE) */
		0,			/* no timeout */
		_PATH_LOGIN,		/* default login program */
		"tty1",			/* default tty line */
		"",			/* modem init string */
		ISSUE,			/* default issue file */
		0,			/* no baud rates known yet */
	};

	setlocale(LC_ALL, "");
	bindtextdomain(PACKAGE, LOCALEDIR);
	textdomain(PACKAGE);

#ifdef DEBUGGING
	dbf = fopen("/dev/ttyp0", "w");
	{
		int i;
		for(i = 1; i < argc; i++) {
			debug(argv[i]);
		}
	}
#endif /* DEBUGGING */

	/* Parse command-line arguments. */

	parse_args(argc, argv, &options);

#ifdef __linux__
	setsid();
#endif

	/* Update the utmp file. */

#ifdef	SYSV_STYLE
	update_utmp(options.tty);
#endif

	debug("calling open_tty\n");
	/* Open the tty as standard { input, output, error }. */
	open_tty(options.tty, &termios, options.flags & F_LOCAL);

	tcsetpgrp(STDIN_FILENO, getpid());
	/* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */
	debug("calling termio_init\n");
	termio_init(&termios, &options);

	/* write the modem init string and DON'T flush the buffers */
	if (options.flags & F_INITSTRING) {
		debug("writing init string\n");
		ignore_result( write(1,
				options.initstring, strlen(options.initstring)) );
	}

	if (!(options.flags & F_LOCAL)) {
		/* go to blocking write mode unless -L is specified */
		fcntl(STDOUT_FILENO, F_SETFL,
				fcntl(STDOUT_FILENO, F_GETFL, 0) & ~O_NONBLOCK);
	}

	/* Optionally detect the baud rate from the modem status message. */
	debug("before autobaud\n");
	if (options.flags & F_PARSE)
		auto_baud(&termios);

	/* Set the optional timer. */
	if (options.timeout)
		(void) alarm((unsigned) options.timeout);

	/* optionally wait for CR or LF before writing /etc/issue */
	if (options.flags & F_WAITCRLF) {
		char ch;

		debug("waiting for cr-lf\n");
		while(read(STDIN_FILENO, &ch, 1) == 1) {
			ch &= 0x7f;   /* strip "parity bit" */
#ifdef DEBUGGING
			fprintf(dbf, "read %c\n", ch);
#endif
			if (ch == '\n' || ch == '\r') break;
		}
	}

	chardata = init_chardata;
	if (!(options.flags & F_NOPROMPT)) {
		/* Read the login name. */
		debug("reading login name\n");
		while ((logname = get_logname(&options,
					      &chardata, &termios)) == 0)
			next_speed(&termios, &options);
	}

	/* Disable timer. */

	if (options.timeout)
		(void) alarm(0);

	/* Finalize the termios settings. */

	termio_final(&options, &termios, &chardata);

	/* Now the newline character should be properly written. */

	ignore_result( write(STDOUT_FILENO, "\n", 1) );

	/* Let the login program take care of password validation. */

	(void) execl(options.login, options.login, "--", logname, NULL);
	error(_("%s: can't exec %s: %m"), options.tty, options.login);
}

/* parse-args - parse command-line arguments */

void parse_args(argc, argv, op)
	int     argc;
	char  **argv;
	struct options *op;
{
	extern char *optarg;		/* getopt */
	extern int optind;			/* getopt */
	int     c;

	enum {
		VERSION_OPTION = CHAR_MAX + 1,
		HELP_OPTION
	};
	static const struct option longopts[] = {
		{  "8bits",	     no_argument,	 0,  '8'  },
		{  "noreset",	     no_argument,	 0,  'c'  },
		{  "issue-file",     required_argument,  0,  'f'  },
		{  "flow-control",   no_argument,	 0,  'h'  },
		{  "host",	     required_argument,  0,  'H'  },
		{  "noissue",	     no_argument,	 0,  'i'  },
		{  "init-string",    required_argument,  0,  'I'  },
		{  "login-program",  required_argument,  0,  'l'  },
		{  "local-line",     no_argument,	 0,  'L'  },
		{  "extract-baud",   no_argument,	 0,  'm'  },
		{  "skip-login",     no_argument,	 0,  'n'  },
		{  "keep-baud",      no_argument,	 0,  's'  },
		{  "timeout",	     required_argument,  0,  't'  },
		{  "detect-case",    no_argument,	 0,  'U'  },
		{  "wait-cr",	     no_argument,	 0,  'w'  },
		{  "version",	     no_argument,	 0,  VERSION_OPTION  },
		{  "help",	     no_argument,	 0,  HELP_OPTION     },
		{ NULL, 0, 0, 0 }
	};

	while ((c = getopt_long(argc, argv, "8cf:hH:iI:l:Lmnst:Uw",
				longopts, NULL)) != -1) {
		switch (c) {
		case '8':
			op->eightbits = 1;
			break;
		case 'c':
			op->flags |= F_KEEPCFLAGS;
			break;
		case 'f':				/* custom issue file */
			op->flags |= F_CUSTISSUE;
			op->issue = optarg;
			break;
		case 'h':				/* enable h/w flow control */
			op->flags |= F_RTSCTS;
			break;
		case 'H':				/* fake login host */
			fakehost = optarg;
			break;
		case 'i':				/* do not show /etc/issue */
			op->flags &= ~F_ISSUE;
			break;
		case 'I':
		{
			char ch, *p, *q;
			int i;

			op->initstring = xmalloc(strlen(optarg) + 1);

			/* copy optarg into op->initstring decoding \ddd octal
			 * codes into chars
			 */
			q = op->initstring;
			p = optarg;
			while (*p) {
				if (*p == '\\') {		/* know \\ means \ */
					p++;
					if (*p == '\\') {
						ch = '\\';
						p++;
					} else {		/* handle \000 - \177 */
						ch = 0;
						for (i = 1; i <= 3; i++) {
							if (*p >= '0' && *p <= '7') {
								ch <<= 3;
								ch += *p - '0';
								p++;
							} else
								break;
						}
					}
					*q++ = ch;
				} else {
					*q++ = *p++;
				}
			}
			*q = '\0';
			op->flags |= F_INITSTRING;
			break;
		}
		case 'l':
			op->login = optarg;			/* non-default login program */
			break;
		case 'L':				/* force local */
			op->flags |= F_LOCAL;
			break;
		case 'm':				/* parse modem status message */
			op->flags |= F_PARSE;
			break;
		case 'n':
			op->flags |= F_NOPROMPT;
			break;
		case 's':
			op->flags |= F_KEEPSPEED;		/* keep kernel defined speed */
			break;
		case 't':				/* time out */
			if ((op->timeout = atoi(optarg)) <= 0)
				error(_("bad timeout value: %s"), optarg);
			break;
		case 'U':
			op->flags |= F_LCUC;
			break;
		case 'w':
			op->flags |= F_WAITCRLF;
			break;
		case VERSION_OPTION:
			printf(_("%s from %s\n"), program_invocation_short_name,
					PACKAGE_STRING);
			exit(EXIT_SUCCESS);
		case HELP_OPTION:
			usage(stdout);
		default:
			usage(stderr);
		}
	}

	debug("after getopt loop\n");

	if (argc < optind + 2) {			/* check parameter count */
		warnx(_("not enough arguments"));
		usage(stderr);
	}

	/* we loosen up a bit and accept both "baudrate tty" and "tty baudrate" */
	if('0' <= argv[optind][0] && argv[optind][0] <= '9') {
		/* a number first, assume it's a speed (BSD style) */
		parse_speeds(op, argv[optind++]);	/* baud rate(s) */
		op->tty = argv[optind];			/* tty name */
	} else {
		op->tty = argv[optind++];		/* tty name */
		parse_speeds(op, argv[optind]);		/* baud rate(s) */
	}

	optind++;
	if (argc > optind && argv[optind])
		setenv ("TERM", argv[optind], 1);

#ifdef DO_DEVFS_FIDDLING
	/*
	 * some devfs junk, following Goswin Brederlow:
	 *   turn ttyS<n> into tts/<n>
	 *   turn tty<n> into vc/<n>
	 */
	if (op->tty && strlen(op->tty) < 90) {
		char dev_name[100];
		struct stat st;

		if (strncmp(op->tty, "ttyS", 4) == 0) {
			strcpy(dev_name, "/dev/");
			strcat(dev_name, op->tty);
			if (stat(dev_name, &st) < 0) {
				strcpy(dev_name, "/dev/tts/");
				strcat(dev_name, op->tty + 4);
				if (stat(dev_name, &st) == 0)
					op->tty = xstrdup(dev_name + 5);
			}
		} else if (strncmp(op->tty, "tty", 3) == 0) {
			strcpy(dev_name, "/dev/");
			strncat(dev_name, op->tty, 90);
			if (stat(dev_name, &st) < 0) {
				strcpy(dev_name, "/dev/vc/");
				strcat(dev_name, op->tty + 3);
				if (stat(dev_name, &st) == 0)
					op->tty = xstrdup(dev_name + 5);
			}
		}
	}
#endif /* DO_DEVFS_FIDDLING */

	debug("exiting parseargs\n");
}

/* parse_speeds - parse alternate baud rates */

void parse_speeds(op, arg)
	struct options *op;
	char   *arg;
{
	char   *cp;

	debug("entered parse_speeds\n");
	for (cp = strtok(arg, ","); cp != 0; cp = strtok((char *) 0, ",")) {
		if ((op->speeds[op->numspeed++] = bcode(cp)) <= 0)
			error(_("bad speed: %s"), cp);
		if (op->numspeed >= MAX_SPEED)
			error(_("too many alternate speeds"));
	}
	debug("exiting parsespeeds\n");
}

#ifdef	SYSV_STYLE

/* update_utmp - update our utmp entry */
void update_utmp(line)
	char   *line;
{
	struct  utmp ut;
	time_t  t;
	int     mypid = getpid();
	struct  utmp *utp;

	/*
	 * The utmp file holds miscellaneous information about things started by
	 * /sbin/init and other system-related events. Our purpose is to update
	 * the utmp entry for the current process, in particular the process type
	 * and the tty line we are listening to. Return successfully only if the
	 * utmp file can be opened for update, and if we are able to find our
	 * entry in the utmp file.
	 */

	utmpname(_PATH_UTMP);
	setutent();

	/* Find mypid in utmp. Earlier code here tested only
	   utp->ut_type != INIT_PROCESS, so maybe the >= here should be >.
	   The present code is taken from login.c, so if this is changed,
	   maybe login has to be changed as well. */
	while ((utp = getutent()))
		if (utp->ut_pid == mypid
				&& utp->ut_type >= INIT_PROCESS
				&& utp->ut_type <= DEAD_PROCESS)
			break;

	if (utp) {
		memcpy(&ut, utp, sizeof(ut));
	} else {
		/* some inits don't initialize utmp... */
		memset(&ut, 0, sizeof(ut));
		strncpy(ut.ut_id, line + 3, sizeof(ut.ut_id));
	}

	strncpy(ut.ut_user, "LOGIN", sizeof(ut.ut_user));
	strncpy(ut.ut_line, line, sizeof(ut.ut_line));
	if (fakehost)
		strncpy(ut.ut_host, fakehost, sizeof(ut.ut_host));
	time(&t);
	ut.ut_time = t;
	ut.ut_type = LOGIN_PROCESS;
	ut.ut_pid = mypid;

	pututline(&ut);
	endutent();

	{
#ifdef HAVE_UPDWTMP
		updwtmp(_PATH_WTMP, &ut);
#else
		int ut_fd;
		int lf;

		if ((lf = open(_PATH_WTMPLOCK, O_CREAT|O_WRONLY, 0660)) >= 0) {
			flock(lf, LOCK_EX);
			if ((ut_fd = open(_PATH_WTMP, O_APPEND|O_WRONLY)) >= 0) {
				ignore_result( write(ut_fd, &ut, sizeof(ut)) );
				close(ut_fd);
			}
			flock(lf, LOCK_UN);
			close(lf);
		}
#endif /* HAVE_UPDWTMP */
	}
}

#endif /* SYSV_STYLE */

/* open_tty - set up tty as standard { input, output, error } */
void open_tty(tty, tp, local)
	char   *tty;
	struct termios *tp;
	int    local;
{
	/* Get rid of the present standard { output, error} if any. */

	(void) close(STDOUT_FILENO);
	(void) close(STDERR_FILENO);
	errno = 0;					/* ignore above errors */

	/* Set up new standard input, unless we are given an already opened port. */

	if (strcmp(tty, "-")) {
		struct stat st;

		/* Sanity checks... */

		if (chdir("/dev"))
			error(_("/dev: chdir() failed: %m"));
		if (stat(tty, &st) < 0)
			error("/dev/%s: %m", tty);
		if ((st.st_mode & S_IFMT) != S_IFCHR)
			error(_("/dev/%s: not a character device"), tty);

		/* Open the tty as standard input. */

		(void) close(STDIN_FILENO);
		errno = 0;				/* ignore close(2) errors */

		debug("open(2)\n");
		if (open(tty, O_RDWR|O_NONBLOCK, 0) != 0)
			error(_("/dev/%s: cannot open as standard input: %m"), tty);

	} else {

		/*
		 * Standard input should already be connected to an open port. Make
		 * sure it is open for read/write.
		 */

		if ((fcntl(STDIN_FILENO, F_GETFL, 0) & O_RDWR) != O_RDWR)
			error(_("%s: not open for read/write"), tty);
	}

	/* Set up standard output and standard error file descriptors. */
	debug("duping\n");
	/* set up stdout and stderr */
	if (dup(STDIN_FILENO) != 1 || dup(STDIN_FILENO) != 2)
		error(_("%s: dup problem: %m"), tty);	/* we have a problem */

	/*
	 * The following ioctl will fail if stdin is not a tty, but also when
	 * there is noise on the modem control lines. In the latter case, the
	 * common course of action is (1) fix your cables (2) give the modem more
	 * time to properly reset after hanging up. SunOS users can achieve (2)
	 * by patching the SunOS kernel variable "zsadtrlow" to a larger value;
	 * 5 seconds seems to be a good value.
	 */

	if (tcgetattr(STDIN_FILENO, tp) < 0)
		error("%s: tcgetattr: %m", tty);

	/*
	 * It seems to be a terminal. Set proper protections and ownership. Mode
	 * 0622 is suitable for SYSV <4 because /bin/login does not change
	 * protections. SunOS 4 login will change the protections to 0620 (write
	 * access for group tty) after the login has succeeded.
	 *
	 * Linux login(1) will change tty permissions.
	 */

	/*
	 * Let us use 0600 for Linux for the period between getty and login
	 */
	ignore_result( chown(tty, 0, 0) );		/* root, sys */
	ignore_result( chmod(tty, 0600) );		/* 0622: crw--w--w- */
	errno = 0;					/* ignore above errors */
}

/* termio_init - initialize termios settings */

char gbuf[1024];
char area[1024];

void termio_init(tp, op)
	struct termios *tp;
	struct options *op;
{
	speed_t ispeed, ospeed;

	if (op->flags & F_KEEPSPEED) {
		ispeed = cfgetispeed(tp);		/* save the original setting */
		ospeed = cfgetospeed(tp);
	} else
		ospeed = ispeed = op->speeds[FIRST_SPEED];

	/*
	 * Initial termios settings: 8-bit characters, raw-mode, blocking i/o.
	 * Special characters are set after we have read the login name; all
	 * reads will be done in raw mode anyway. Errors will be dealt with
	 * lateron.
	 */
	/* flush input and output queues, important for modems! */
	(void) tcflush(STDIN_FILENO, TCIOFLUSH);

	tp->c_iflag = tp->c_lflag = tp->c_oflag = 0;

	if (!(op->flags & F_KEEPCFLAGS))
		tp->c_cflag = CS8 | HUPCL | CREAD | (tp->c_cflag & CLOCAL);

	/* Note that the speed is stored in the c_cflag termios field, so we have
	 * set the speed always when the cflag se reseted.
	 */
	cfsetispeed(tp, ispeed);
	cfsetospeed(tp, ospeed);

	if (op->flags & F_LOCAL) {
		tp->c_cflag |= CLOCAL;
	}

#ifdef HAVE_STRUCT_TERMIOS_C_LINE
	tp->c_line = 0;
#endif
	tp->c_cc[VMIN] = 1;
	tp->c_cc[VTIME] = 0;

	/* Optionally enable hardware flow control */

#ifdef	CRTSCTS
	if (op->flags & F_RTSCTS)
		tp->c_cflag |= CRTSCTS;
#endif

	(void) tcsetattr(STDIN_FILENO, TCSANOW, tp);

	/* go to blocking input even in local mode */
	fcntl(STDIN_FILENO, F_SETFL, fcntl(STDIN_FILENO, F_GETFL, 0) & ~O_NONBLOCK);

	debug("term_io 2\n");
}

/* auto_baud - extract baud rate from modem status message */
void auto_baud(tp)
	struct termios *tp;
{
	int     speed;
	int     vmin;
	unsigned iflag;
	char    buf[BUFSIZ];
	char   *bp;
	int     nread;

	/*
	 * This works only if the modem produces its status code AFTER raising
	 * the DCD line, and if the computer is fast enough to set the proper
	 * baud rate before the message has gone by. We expect a message of the
	 * following format:
	 *
	 * <junk><number><junk>
	 *
	 * The number is interpreted as the baud rate of the incoming call. If the
	 * modem does not tell us the baud rate within one second, we will keep
	 * using the current baud rate. It is advisable to enable BREAK
	 * processing (comma-separated list of baud rates) if the processing of
	 * modem status messages is enabled.
	 */

	/*
	 * Use 7-bit characters, don't block if input queue is empty. Errors will
	 * be dealt with lateron.
	 */

	iflag = tp->c_iflag;
	tp->c_iflag |= ISTRIP;			/* enable 8th-bit stripping */
	vmin = tp->c_cc[VMIN];
	tp->c_cc[VMIN] = 0;				/* don't block if queue empty */
	tcsetattr(STDIN_FILENO, TCSANOW, tp);

	/*
	 * Wait for a while, then read everything the modem has said so far and
	 * try to extract the speed of the dial-in call.
	 */

	(void) sleep(1);
	if ((nread = read(STDIN_FILENO, buf, sizeof(buf) - 1)) > 0) {
		buf[nread] = '\0';
		for (bp = buf; bp < buf + nread; bp++) {
			if (isascii(*bp) && isdigit(*bp)) {
				if ((speed = bcode(bp))) {
					cfsetispeed(tp, speed);
					cfsetospeed(tp, speed);
				}
				break;
			}
		}
	}
	/* Restore terminal settings. Errors will be dealt with lateron. */

	tp->c_iflag = iflag;
	tp->c_cc[VMIN] = vmin;
	(void) tcsetattr(STDIN_FILENO, TCSANOW, tp);
}

/* do_prompt - show login prompt, optionally preceded by /etc/issue contents */
	void
do_prompt(op, tp)
	struct options *op;
	struct termios *tp;
{
#ifdef	ISSUE
	FILE    *fd;
	int     oflag;
	int     c;
	struct utsname uts;

	(void) uname(&uts);
#endif /* ISSUE */

	ignore_result( write(STDOUT_FILENO, "\r\n", 2) );	/* start a new line */
#ifdef	ISSUE					/* optional: show /etc/issue */
	if ((op->flags & F_ISSUE) && (fd = fopen(op->issue, "r"))) {
		oflag = tp->c_oflag;			/* save current setting */
		tp->c_oflag |= (ONLCR | OPOST);		/* map NL in output to CR-NL */
		(void) tcsetattr(STDIN_FILENO, TCSADRAIN, tp);

		while ((c = getc(fd)) != EOF) {
			if (c == '\\') {
				c = getc(fd);

				switch (c) {
				case 's':
					(void) printf ("%s", uts.sysname);
					break;
				case 'n':
					(void) printf ("%s", uts.nodename);
					break;
				case 'r':
					(void) printf ("%s", uts.release);
					break;
				case 'v':
					(void) printf ("%s", uts.version);
					break;
				case 'm':
					(void) printf ("%s", uts.machine);
					break;
				case 'o':
				{
					char domainname[MAXHOSTNAMELEN+1];
#ifdef HAVE_GETDOMAINNAME
					if (getdomainname(domainname, sizeof(domainname)))
#endif /* HAVE_GETDOMAINNAME */
						strcpy(domainname, "unknown_domain");
					domainname[sizeof(domainname)-1] = '\0';
					printf ("%s", domainname);
					break;
				}
				case 'O':
				{
					char *dom = "unknown_domain";
					char host[MAXHOSTNAMELEN+1];
					struct addrinfo hints, *info = NULL;

					memset(&hints, 0, sizeof(hints));
					hints.ai_flags = AI_CANONNAME;

					if (gethostname(host, sizeof(host)) ||
							getaddrinfo(host, NULL, &hints, &info) ||
							info == NULL)
						fputs(dom, stdout);
					else {
						char *canon;

						if (info->ai_canonname &&
								(canon = strchr(info->ai_canonname, '.')))
							dom = canon + 1;
						fputs(dom, stdout);
						freeaddrinfo(info);
					}
					break;
				}
				case 'd':
				case 't':
				{
					time_t now;
					struct tm *tm;

					(void) time (&now);
					tm = localtime(&now);

					if (c == 'd')
						(void) printf ("%s %s %d  %d",
								nl_langinfo(ABDAY_1 + tm->tm_wday),
								nl_langinfo(ABMON_1 + tm->tm_mon),
								tm->tm_mday,
								tm->tm_year < 70 ? tm->tm_year + 2000 :
								tm->tm_year + 1900);
					else
						(void) printf ("%02d:%02d:%02d",
								tm->tm_hour, tm->tm_min, tm->tm_sec);
					break;
				}
				case 'l':
					(void) printf ("%s", op->tty);
					break;
				case 'b':
				{
					int i;

					for (i = 0; speedtab[i].speed; i++) {
						if (speedtab[i].code == cfgetispeed(tp)) {
							printf("%ld", speedtab[i].speed);
							break;
						}
					}
					break;
				}
				case 'u':
				case 'U':
				{
					int users = 0;
					struct utmp *ut;
					setutent();
					while ((ut = getutent()))
						if (ut->ut_type == USER_PROCESS)
							users++;
					endutent();
					printf ("%d ", users);
					if (c == 'U')
						printf ((users == 1) ? _("user") : _("users"));
					break;
				}
				default:
					(void) putchar(c);
				}
			} else
				(void) putchar(c);
		}
		fflush(stdout);

		tp->c_oflag = oflag;			/* restore settings */
		(void) tcsetattr(STDIN_FILENO, TCSADRAIN, tp);	/* wait till output is gone */
		(void) fclose(fd);
	}
#endif /* ISSUE */
	{
		char hn[MAXHOSTNAMELEN+1];
		if (gethostname(hn, sizeof(hn)) == 0)
			ignore_result( write(1, hn, strlen(hn)) );
	}
	ignore_result( write(STDOUT_FILENO, LOGIN, sizeof(LOGIN) - 1) );	/* always show login prompt */
}

/* next_speed - select next baud rate */
void next_speed(tp, op)
	struct termios *tp;
	struct options *op;
{
	static int baud_index = -1;

	if (baud_index == -1)
		/*
		 * if the F_KEEPSPEED flags is set then the FIRST_SPEED is not
		 * tested yet (see termio_init()).
		 */
		baud_index = (op->flags & F_KEEPSPEED) ? FIRST_SPEED :
			1 % op->numspeed;
	else
		baud_index = (baud_index + 1) % op->numspeed;

	cfsetispeed(tp, op->speeds[baud_index]);
	cfsetospeed(tp, op->speeds[baud_index]);
	(void) tcsetattr(STDIN_FILENO, TCSANOW, tp);
}

/* get_logname - get user name, establish parity, speed, erase, kill, eol */

char   *get_logname(op, cp, tp)
	struct options *op;
	struct chardata *cp;
	struct termios *tp;
{
	static char logname[BUFSIZ];
	char   *bp;
	char    c;				/* input character, full eight bits */
	char    ascval;			/* low 7 bits of input character */
	int     bits;			/* # of "1" bits per character */
	int     mask;			/* mask with 1 bit up */
	static char *erase[] = {		/* backspace-space-backspace */
		"\010\040\010",			/* space parity */
		"\010\040\010",			/* odd parity */
		"\210\240\210",			/* even parity */
		"\210\240\210",			/* no parity */
	};

	/* Initialize kill, erase, parity etc. (also after switching speeds). */

	*cp = init_chardata;

	/* Flush pending input (esp. after parsing or switching the baud rate). */

	(void) sleep(1);
	(void) tcflush(STDIN_FILENO, TCIFLUSH);

	/* Prompt for and read a login name. */

	for (*logname = 0; *logname == 0; /* void */ ) {
		/* Write issue file and prompt, with "parity" bit == 0. */
		do_prompt(op, tp);

		/* Read name, watch for break, parity, erase, kill, end-of-line. */
		for (bp = logname, cp->eol = 0; cp->eol == 0; /* void */ ) {

			/* Do not report trivial EINTR/EIO errors. */
			if (read(STDIN_FILENO, &c, 1) < 1) {
				if (errno == EINTR || errno == EIO)
					exit(EXIT_SUCCESS);
				error(_("%s: read: %m"), op->tty);
			}
			/* Do BREAK handling elsewhere. */
			if ((c == 0) && op->numspeed > 1)
				return EXIT_SUCCESS;
			/* Do parity bit handling. */
			if (op->eightbits) {
				ascval = c;
			} else if (c != (ascval = (c & 0177))) {	/* "parity" bit on */
				for (bits = 1, mask = 1; mask & 0177; mask <<= 1)
					if (mask & ascval)
						bits++;			/* count "1" bits */
				cp->parity |= ((bits & 1) ? 1 : 2);
			}
			/* Do erase, kill and end-of-line processing. */
			switch (ascval) {
			case CR:
			case NL:
				*bp = 0;			/* terminate logname */
				cp->eol = ascval;		/* set end-of-line char */
				break;
			case BS:
			case DEL:
			case '#':
				cp->erase = ascval;		/* set erase character */
				if (bp > logname) {
					ignore_result( write(1, erase[cp->parity], 3) );
					bp--;
				}
				break;
			case CTL('U'):
			case '@':
				cp->kill = ascval;		/* set kill character */
				while (bp > logname) {
					ignore_result( write(1, erase[cp->parity], 3) );
					bp--;
				}
				break;
			case CTL('D'):
				exit(EXIT_SUCCESS);
			default:
				if (!isascii(ascval) || !isprint(ascval)) {
					/* ignore garbage characters */ ;
				} else if (bp - logname >= sizeof(logname) - 1) {
					error(_("%s: input overrun"), op->tty);
				} else {
					ignore_result( write(1, &c, 1) );	/* echo the character */
					*bp++ = ascval;		/* and store it */
				}
				break;
			}
		}
	}
	/* Handle names with upper case and no lower case. */
	if ((op->flags & F_LCUC) && (cp->capslock = caps_lock(logname))) {
		for (bp = logname; *bp; bp++)
			if (isupper(*bp))
				*bp = tolower(*bp);		/* map name to lower case */
	}
	return logname;
}

/* termio_final - set the final tty mode bits */
void termio_final(op, tp, cp)
	struct options *op;
	struct termios *tp;
	struct chardata *cp;
{
	/* General terminal-independent stuff. */
	tp->c_iflag |= IXON | IXOFF;		/* 2-way flow control */
	tp->c_lflag |= ICANON | ISIG | ECHO | ECHOE | ECHOK| ECHOKE;
	/* no longer| ECHOCTL | ECHOPRT*/
	tp->c_oflag |= OPOST;
	/* tp->c_cflag = 0; */
	tp->c_cc[VINTR] = DEF_INTR;			/* default interrupt */
	tp->c_cc[VQUIT] = DEF_QUIT;			/* default quit */
	tp->c_cc[VEOF] = DEF_EOF;			/* default EOF character */
	tp->c_cc[VEOL] = DEF_EOL;
#ifdef __linux__
	tp->c_cc[VSWTC] = DEF_SWITCH;		/* default switch character */
#elif defined(VSWTCH)
	tp->c_cc[VSWTCH] = DEF_SWITCH;		/* default switch character */
#endif /* __linux__ */

	/* Account for special characters seen in input. */
	if (cp->eol == CR) {
		tp->c_iflag |= ICRNL;			/* map CR in input to NL */
		tp->c_oflag |= ONLCR;			/* map NL in output to CR-NL */
	}
	tp->c_cc[VERASE] = cp->erase;		/* set erase character */
	tp->c_cc[VKILL] = cp->kill;			/* set kill character */

	/* Account for the presence or absence of parity bits in input. */
	switch (cp->parity) {
		case 0:					/* space (always 0) parity */
			break;
		case 1:					/* odd parity */
			tp->c_cflag |= PARODD;
			/* FALLTHROUGH */
		case 2:					/* even parity */
			tp->c_cflag |= PARENB;
			tp->c_iflag |= INPCK | ISTRIP;
			/* FALLTHROUGH */
		case (1 | 2):				/* no parity bit */
			tp->c_cflag &= ~CSIZE;
			tp->c_cflag |= CS7;
			break;
	}
	/* Account for upper case without lower case. */
	if (cp->capslock) {
#ifdef IUCLC
		tp->c_iflag |= IUCLC;
#endif
#ifdef XCASE
		tp->c_lflag |= XCASE;
#endif
#ifdef OLCUC
		tp->c_oflag |= OLCUC;
#endif
	}
	/* Optionally enable hardware flow control */
#ifdef	CRTSCTS
	if (op->flags & F_RTSCTS)
		tp->c_cflag |= CRTSCTS;
#endif

	/* Finally, make the new settings effective */
	if (tcsetattr(STDIN_FILENO, TCSANOW, tp) < 0)
		error("%s: tcsetattr: TCSANOW: %m", op->tty);
}

/* caps_lock - string contains upper case without lower case */
int caps_lock(s)
	char   *s;
{
	int     capslock;

	for (capslock = 0; *s; s++) {
		if (islower(*s))
			return EXIT_SUCCESS;
		if (capslock == 0)
			capslock = isupper(*s);
	}
	return capslock;
}

/* bcode - convert speed string to speed code; return 0 on failure */
int bcode(s)
	char   *s;
{
	struct Speedtab *sp;
	long    speed = atol(s);

	for (sp = speedtab; sp->speed; sp++)
		if (sp->speed == speed)
			return sp->code;
	return 0;
}

/* usage - explain */
void __attribute__((__noreturn__)) usage(FILE *out)
{
	fprintf(out, _(
		"\nUsage:\n"
		"    %1$s [options] line baud_rate,... [termtype]\n"
		"    %1$s [options] baud_rate,... line [termtype]\n"),
		program_invocation_short_name);

	fprintf(out, _(
		"\nOptions:\n"
		" -8, --8bits                assume 8-bit tty\n"
		" -c, --noreset              do not reset control mode\n"
		" -f, --issue-file FILE      display issue file\n"
		" -h, --flow-control         enable hardware flow control\n"
		" -H, --host HOSTNAME        specify login host\n"
		" -i, --noissue              do not display issue file\n"
		" -I, --init-string STRING   set init string\n"
		" -l, --login-program FILE   specify login program\n"
		" -L, --local-line           force local line\n"
		" -m, --extract-baud         extract baud rate during connect\n"
		" -n, --skip-login           do not prompt for login\n"
		" -s, --keep-baud            try to keep baud rate after break\n"
		" -t, --timeout NUMBER       login process timeout\n"
		" -U, --detect-case          detect uppercase terminal\n"
		" -w, --wait-cr              wait carriage-return\n"
		"     --version              output version information and exit\n"
		"     --help                 display this help and exit\n\n"));

	exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}

/* error - report errors to console or syslog; only understands %s and %m */
#define	str2cpy(b,s1,s2)	strcat(strcpy(b,s1),s2)

void error(const char *fmt, ...) {
	va_list ap;
#ifndef	USE_SYSLOG
	int     fd;
#endif
	char    buf[BUFSIZ];
	char   *bp;

	/*
	 * If the diagnostic is reported via syslog(3), the process name is
	 * automatically prepended to the message. If we write directly to
	 * /dev/console, we must prepend the process name ourselves.
	 */

#ifdef USE_SYSLOG
	buf[0] = '\0';
	bp = buf;
#else
	(void) str2cpy(buf, program_invocation_short_name, ": ");
	bp = buf + strlen(buf);
#endif /* USE_SYSLOG */

	/*
	 * %s expansion is done by hand. On a System V Release 2 system without
	 * shared libraries and without syslog(3), linking with the the stdio
	 * library would make the program three times as big...
	 *
	 * %m expansion is done here as well. Too bad syslog(3) does not have a
	 * vsprintf() like interface.
	 */

	va_start(ap, fmt);
	while (*fmt && bp < &buf[BUFSIZ-1]) {
		if (strncmp(fmt, "%s", 2) == 0) {
			xstrncpy(bp, va_arg(ap, char *), &buf[BUFSIZ-1] - bp);
			bp += strlen(bp);
			fmt += 2;
		} else if (strncmp(fmt, "%m", 2) == 0) {
			xstrncpy(bp, strerror(errno), &buf[BUFSIZ-1] - bp);
			bp += strlen(bp);
			fmt += 2;
		} else {
			*bp++ = *fmt++;
		}
	}
	*bp = 0;
	va_end(ap);

	/*
	 * Write the diagnostic directly to /dev/console if we do not use the
	 * syslog(3) facility.
	 */

#ifdef	USE_SYSLOG
	(void) openlog(program_invocation_short_name, LOG_PID, LOG_AUTHPRIV);
	(void) syslog(LOG_ERR, "%s", buf);
	closelog();
#else
	/* Terminate with CR-LF since the console mode is unknown. */
	(void) strcat(bp, "\r\n");
	if ((fd = open("/dev/console", 1)) >= 0) {
		ignore_result( write(fd, buf, strlen(buf)) );
		(void) close(fd);
	}
#endif /* USE_SYSLOG */
	(void) sleep((unsigned) 10);		/* be kind to init(8) */
	exit(EXIT_FAILURE);
}