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.

		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(0, 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");
	if (dup(0) != 1 || dup(0) != 2)	/* set up stdout and stderr */
		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 (ioctl(0, TCGETA, tp) < 0)
		error("%s: ioctl: %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.
	 */

#ifdef DEBIAN
	{
		/* tty to root.dialout 660 */
		struct group *gr;
		int id;

		id = (gr = getgrnam("dialout")) ? gr->gr_gid : 0;
		chown(tty, 0, id);
		chmod(tty, 0660);

		/* vcs,vcsa to root.sys 600 */
		if (!strncmp(tty, "tty", 3) && isdigit(tty[3])) {
			char *vcs, *vcsa;

			if (!(vcs = strdup(tty)))
				error("Can't malloc for vcs");
			if (!(vcsa = malloc(strlen(tty) + 2)))
				error("Can't malloc for vcsa");
			strcpy(vcs, "vcs");
			strcpy(vcs + 3, tty + 3);
			strcpy(vcsa, "vcsa");
			strcpy(vcsa + 4, tty + 3);

			id = (gr = getgrnam("sys")) ? gr->gr_gid : 0;
			chown(vcs, 0, id);
			chmod(vcs, 0600);
			chown(vcsa, 0, id);
			chmod(vcs, 0600);

			free(vcs);
			free(vcsa);
		}
	}
#else
	(void) chown(tty, 0, 0);	/* root, sys */
	(void) chmod(tty, 0622);	/* crw--w--w- */
	errno = 0;					/* ignore above errors */
#endif
}

/* termio_init - initialize termio settings */

static void termio_init(struct termio *tp, int speed, struct options *op)
{

	/*
	 * Initial termio 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.
	 */
#ifdef __linux__
	/* flush input and output queues, important for modems! */
	(void) ioctl(0, TCFLSH, TCIOFLUSH);
#endif

	tp->c_cflag = CS8 | HUPCL | CREAD | speed;
	if (op->flags & F_LOCAL) {
		tp->c_cflag |= CLOCAL;
	}

	tp->c_iflag = tp->c_lflag = tp->c_oflag = tp->c_line = 0;
	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) ioctl(0, TCSETA, tp);

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

	debug("term_io 2\n");
}

/* auto_baud - extract baud rate from modem status message */
static void auto_baud(struct termio *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 */
	(void) ioctl(0, TCSETA, 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(0, buf, sizeof(buf) - 1)) > 0) {
		buf[nread] = '\0';
		for (bp = buf; bp < buf + nread; bp++) {
			if (isascii(*bp) && isdigit(*bp)) {
				if ((speed = bcode(bp))) {
					tp->c_cflag &= ~CBAUD;
					tp->c_cflag |= speed;
				}
				break;
			}
		}
	}
	/* Restore terminal settings. Errors will be dealt with lateron. */

	tp->c_iflag = iflag;
	tp->c_cc[VMIN] = vmin;
	(void) ioctl(0, TCSETA, tp);
}

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

	(void) uname(&uts);
#endif

	(void) write(1, "\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) ioctl(0, TCSETAW, 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[256];

					getdomainname(domainname, sizeof(domainname));
					domainname[sizeof(domainname) - 1] = '\0';
					printf("%s", domainname);
				}
					break;

				case 'd':
				case 't':
				{
					char *weekday[] = { "Sun", "Mon", "Tue", "Wed", "Thu",
						"Fri", "Sat"
					};
					char *month[] = { "Jan", "Feb", "Mar", "Apr", "May",
						"Jun", "Jul", "Aug", "Sep", "Oct",
						"Nov", "Dec"
					};
					time_t now;
					struct tm *tm;

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

					if (c == 'd')
						(void) printf("%s %s %d  %d",
									  weekday[tm->tm_wday],
									  month[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 == (tp->c_cflag & CBAUD)) {
							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) ioctl(0, TCSETAW, tp);	/* wait till output is gone */
		(void) fclose(fd);
	}
#endif
#ifdef __linux__
	{
		char hn[MAXHOSTNAMELEN + 1];

		(void) gethostname(hn, MAXHOSTNAMELEN);
		write(1, hn, strlen(hn));
	}
#endif
	(void) write(1, LOGIN, sizeof(LOGIN) - 1);	/* always show login prompt */
}

/* next_speed - select next baud rate */
static void next_speed(struct termio *tp, struct options *op)
{
	static int baud_index = FIRST_SPEED;	/* current speed index */

	baud_index = (baud_index + 1) % op->numspeed;
	tp->c_cflag &= ~CBAUD;
	tp->c_cflag |= op->speeds[baud_index];
	(void) ioctl(0, TCSETA, tp);
}

/* get_logname - get user name, establish parity, speed, erase, kill, eol */
/* return NULL on failure, logname on success */
static char *get_logname(struct options *op, struct chardata *cp, struct termio *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) ioctl(0, TCFLSH, 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(0, &c, 1) < 1) {
				if (errno == EINTR || errno == EIO)
					exit(0);
				error("%s: read: %m", op->tty);
			}
			/* Do BREAK handling elsewhere. */

			if ((c == 0) && op->numspeed > 1)
				/* return (0); */
				return NULL;

			/* Do parity bit handling. */

			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) {
					(void) write(1, erase[cp->parity], 3);
					bp--;
				}
				break;
			case CTL('U'):
			case '@':
				cp->kill = ascval;	/* set kill character */
				while (bp > logname) {
					(void) write(1, erase[cp->parity], 3);
					bp--;
				}
				break;
			case CTL('D'):
				exit(0);
			default:
				if (!isascii(ascval) || !isprint(ascval)) {
					/* ignore garbage characters */ ;
				} else if (bp - logname >= sizeof(logname) - 1) {
					error("%s: input overrun", op->tty);
				} else {
					(void) write(1, &c, 1);	/* echo the character */
					*bp++ = ascval;	/* and store it */
				}
				break;
			}
		}
	}
	/* Handle names with upper case and no lower case. */

	if ((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 */
static void termio_final(struct options *op, struct termio *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 */
#else
	tp->c_cc[VSWTCH] = DEF_SWITCH;	/* default switch character */
#endif

	/* 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) {
		tp->c_iflag |= IUCLC;
		tp->c_lflag |= XCASE;
		tp->c_oflag |= OLCUC;
	}
	/* Optionally enable hardware flow control */

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

	/* Finally, make the new settings effective */

	if (ioctl(0, TCSETA, tp) < 0)
		error("%s: ioctl: TCSETA: %m", op->tty);
}

/* caps_lock - string contains upper case without lower case */
/* returns 1 if true, 0 if false */
static int caps_lock(const char *s)
{
	int capslock;

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

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

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

/* error - report errors to console or syslog; only understands %s and %m */

#define	str2cpy(b,s1,s2)	strcat(strcpy(b,s1),s2)

/*
 * output error messages
 */
static void error(const char *fmt, ...)
{
	va_list va_alist;
	char buf[256], *bp;

#ifndef	USE_SYSLOG
	int fd;
#endif

#ifdef USE_SYSLOG
	buf[0] = '\0';
	bp = buf;
#else
	strncpy(buf, applet_name, 256);
	strncat(buf, ": ", 256);
	buf[255] = 0;
	bp = buf + strlen(buf);
#endif

	va_start(va_alist, fmt);
	vsnprintf(bp, 256 - strlen(buf), fmt, va_alist);
	buf[255] = 0;
	va_end(va_alist);

#ifdef	USE_SYSLOG
	syslog_msg(LOG_AUTH, LOG_ERR, buf);
#else
	strncat(bp, "\r\n", 256 - strlen(buf));
	buf[255] = 0;
	if ((fd = open("/dev/console", 1)) >= 0) {
		write(fd, buf, strlen(buf));
		close(fd);
	}
#endif
	(void) sleep((unsigned) 10);	/* be kind to init(8) */
	exit(1);
}