getty.c

这是一个SIGMA方案的PMP播放器的UCLINUX程序,可播放DVD,VCD,CD MP3...有很好的参考价值.

/* vi: set sw=4 ts=4: */
/* agetty.c - another getty program for Linux. By W. Z. Venema 1989
   Ported to Linux by Peter Orbaek <[e-mail]>
   This program is freely distributable. The entire man-page used to
   be here. Now read the real man-page agetty.8 instead.

   -f option added by Eric Rasmussen <[e-mail]> - 12/28/95
   
   1999-02-22 Arkadiusz Mi秌iewicz <[e-mail]>
   - added Native Language Support

   1999-05-05 Thorsten Kranzkowski <[e-mail]>
   - enable hardware flow control before displaying /etc/issue
   
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/signal.h>
#include <fcntl.h>
#include <stdarg.h>
#include <ctype.h>
#include <utmp.h>
#include <getopt.h>
#include <termios.h>
#include "busybox.h"

#define _PATH_LOGIN     "/bin/login"

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

extern void updwtmp(const char *filename, const struct utmp *ut);

 /* 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>
#include <time.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 */

 /*
  * SunOS 4.1.1 termio is broken. We must use the termios stuff instead,
  * because the termio -> termios translation does not clear the termios
  * CIBAUD bits. Therefore, the tty driver would sometimes report that input
  * baud rate != output baud rate. I did not notice that problem with SunOS
  * 4.1. We will use termios where available, and termio otherwise.
  */

/* linux 0.12 termio is broken too, if we use it c_cc[VERASE] isn't set
   properly, but all is well if we use termios?! */

#ifdef	TCGETS
#undef	TCGETA
#undef	TCSETA
#undef	TCSETAW
#define	termio	termios
#define	TCGETA	TCGETS
#define	TCSETA	TCSETS
#define	TCSETAW	TCSETSW
#endif

 /*
  * This program tries to not use the standard-i/o library.  This keeps the
  * executable small on systems that do not have shared libraries (System V
  * Release <3).
  */
#ifndef BUFSIZ
#define	BUFSIZ		1024
#endif

 /*
  * 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 */
};

#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! */

/* 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},
};

static void parse_args(int argc, char **argv, struct options *op);
static void parse_speeds(struct options *op, char *arg);
static void update_utmp(char *line);
static void open_tty(char *tty, struct termio *tp, int local);
static void termio_init(struct termio *tp, int speed, struct options *op);
static void auto_baud(struct termio *tp);
static void do_prompt(struct options *op, struct termio *tp);
static void next_speed(struct termio *tp, struct options *op);
static char *get_logname(struct options *op, struct chardata *cp,

				  struct termio *tp);
static void termio_final(struct options *op, struct termio *tp,

				  struct chardata *cp);
static int caps_lock(const char *s);
static int bcode(const char *s);
static void error(const char *fmt, ...);

/* The following is used for understandable diagnostics. */

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

/* ... */
#ifdef DEBUGGING
#define debug(s) fprintf(dbf,s); fflush(dbf)
#define DEBUGTERM "/dev/ttyp0"
FILE *dbf;
#else
#define debug(s)				/* nothing */
#endif

int getty_main(int argc, char **argv)
{
	char *logname = NULL;		/* login name, given to /bin/login */
	struct chardata chardata;	/* set by get_logname() */
	struct termio termio;		/* 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 */
	};

#ifdef DEBUGGING
	dbf = xfopen(DEBUGTERM, "w");

	{
		int i;

		for (i = 1; i < argc; i++) {
			debug(argv[i]);
			debug("\n");
		}
	}
#endif

	/* 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, &termio, options.flags & F_LOCAL);

#ifdef __linux__
	{
		int iv;

		iv = getpid();
		if (ioctl(0, TIOCSPGRP, &iv) < 0)
			perror_msg("ioctl() TIOCSPGRP call failed");
	}
#endif
	/* Initialize the termio settings (raw mode, eight-bit, blocking i/o). */
	debug("calling termio_init\n");
	termio_init(&termio, options.speeds[FIRST_SPEED], &options);

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

	if (!(options.flags & F_LOCAL)) {
		/* go to blocking write mode unless -L is specified */
		fcntl(1, F_SETFL, fcntl(1, 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(&termio);

	/* 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(0, &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, &termio)) == 0) */
		while ((logname = get_logname(&options, &chardata, &termio)) ==
			   NULL) next_speed(&termio, &options);
	}

	/* Disable timer. */

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

	/* Finalize the termio settings. */

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

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

	(void) write(1, "\n", 1);

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

	(void) execl(options.login, options.login, "--", logname, (char *) 0);
	error("%s: can't exec %s: %m", options.tty, options.login);
	return (0);					/* quiet GCC */
}

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

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

	while (isascii(c = getopt(argc, argv, "I:LH:f:hil:mt:wn"))) {
		switch (c) {
		case 'I':
			if (!(op->initstring = strdup(optarg))) {
				error("can't malloc initstring");
				break;
			}
			{
				char ch, *p, *q;
				int i;

				/* 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':				/* force local */
			op->flags |= F_LOCAL;
			break;
		case 'H':				/* fake login host */
			fakehost = optarg;
			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 'i':				/* do not show /etc/issue */
			op->flags &= ~F_ISSUE;
			break;
		case 'l':
			op->login = optarg;	/* non-default login program */
			break;
		case 'm':				/* parse modem status message */
			op->flags |= F_PARSE;
			break;
		case 'n':
			op->flags |= F_NOPROMPT;
			break;
		case 't':				/* time out */
			if ((op->timeout = atoi(optarg)) <= 0)
				error("bad timeout value: %s", optarg);
			break;
		case 'w':
			op->flags |= F_WAITCRLF;
			break;
		default:
			show_usage();
		}
	}
	debug("after getopt loop\n");
	if (argc < optind + 2)		/* check parameter count */
		show_usage();

	/* 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);

	debug("exiting parseargs\n");
}

/* parse_speeds - parse alternate baud rates */

static void parse_speeds(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 */
static void update_utmp(char *line)
{
	struct utmp ut;
	struct utmp *utp;
	time_t t;
	int mypid = getpid();
#if ! (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1))
	struct flock lock;
#endif

	/*
	 * 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();
	while ((utp = getutent())
		   && !(utp->ut_type == INIT_PROCESS && utp->ut_pid == mypid))	/* nothing */
		;

	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));
	}
	/*endutent(); */

	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();

	{
		updwtmp(_PATH_WTMP, &ut);
	}
}

#endif

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

	(void) close(1);
	(void) close(2);
	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(0);
		errno = 0;				/* ignore close(2) errors */