agetty.c

Util-linux 软件包包含许多工具。其中比较重要的是加载、卸载、格式化、分区和管理硬盘驱动器

		  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];
#ifdef HAVE_getdomainname
		     getdomainname(domainname, sizeof(domainname));
#else
		     strcpy(domainname, "unknown_domain");
#endif
		     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 */
void
next_speed(tp, op)
     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 */

char   *get_logname(op, cp, tp)
     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);

	    /* 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 */
void
termio_final(op, tp, cp)
     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 */
int
caps_lock(s)
     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 */
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
usage()
{
    fprintf(stderr, _("Usage: %s [-hiLmw] [-l login_program] [-t timeout] [-I initstring] [-H login_host] baud_rate,... line [termtype]\nor\t[-hiLmw] [-l login_program] [-t timeout] [-I initstring] [-H login_host] line baud_rate,... [termtype]\n"), progname);
    exit(1);
}

/* 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, progname, ": ");
    bp = buf + strlen(buf);
#endif

    /*
     * %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(progname, 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) {
	(void) write(fd, buf, strlen(buf));
	(void) close(fd);
    }
#endif
    (void) sleep((unsigned) 10);		/* be kind to init(8) */
    exit(1);
}