tty.c

Minix3.11的源码。[MINIX 3是一个为高可靠性应用而设计的自由且简洁的类UNIX系统。]

		tp->tty_outrepcode = REVIVE;
	}
  }
  tty_reply(TASK_REPLY, m_ptr->m_source, m_ptr->PROC_NR, r);
}

/*===========================================================================*
 *				do_ioctl				     *
 *===========================================================================*/
PRIVATE void do_ioctl(tp, m_ptr)
register tty_t *tp;
message *m_ptr;			/* pointer to message sent to task */
{
/* Perform an IOCTL on this terminal. Posix termios calls are handled
 * by the IOCTL system call
 */

  int r;
  union {
	int i;
#if ENABLE_SRCCOMPAT
	struct sgttyb sg;
	struct tchars tc;
#endif
  } param;
  size_t size;

  /* Size of the ioctl parameter. */
  switch (m_ptr->TTY_REQUEST) {
    case TCGETS:        /* Posix tcgetattr function */
    case TCSETS:        /* Posix tcsetattr function, TCSANOW option */ 
    case TCSETSW:       /* Posix tcsetattr function, TCSADRAIN option */
    case TCSETSF:	/* Posix tcsetattr function, TCSAFLUSH option */
        size = sizeof(struct termios);
        break;

    case TCSBRK:        /* Posix tcsendbreak function */
    case TCFLOW:        /* Posix tcflow function */
    case TCFLSH:        /* Posix tcflush function */
    case TIOCGPGRP:     /* Posix tcgetpgrp function */
    case TIOCSPGRP:	/* Posix tcsetpgrp function */
        size = sizeof(int);
        break;

    case TIOCGWINSZ:    /* get window size (not Posix) */
    case TIOCSWINSZ:	/* set window size (not Posix) */
        size = sizeof(struct winsize);
        break;

#if ENABLE_SRCCOMPAT
    case TIOCGETP:      /* BSD-style get terminal properties */
    case TIOCSETP:	/* BSD-style set terminal properties */
	size = sizeof(struct sgttyb);
	break;

    case TIOCGETC:      /* BSD-style get terminal special characters */ 
    case TIOCSETC:	/* BSD-style get terminal special characters */ 
	size = sizeof(struct tchars);
	break;
#endif
#if (MACHINE == IBM_PC)
    case KIOCSMAP:	/* load keymap (Minix extension) */
        size = sizeof(keymap_t);
        break;

    case TIOCSFON:	/* load font (Minix extension) */
        size = sizeof(u8_t [8192]);
        break;

#endif
    case TCDRAIN:	/* Posix tcdrain function -- no parameter */
    default:		size = 0;
  }

  r = OK;
  switch (m_ptr->TTY_REQUEST) {
    case TCGETS:
	/* Get the termios attributes. */
	r = sys_vircopy(SELF, D, (vir_bytes) &tp->tty_termios,
		m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS, 
		(vir_bytes) size);
	break;

    case TCSETSW:
    case TCSETSF:
    case TCDRAIN:
	if (tp->tty_outleft > 0) {
		/* Wait for all ongoing output processing to finish. */
		tp->tty_iocaller = m_ptr->m_source;
		tp->tty_ioproc = m_ptr->PROC_NR;
		tp->tty_ioreq = m_ptr->REQUEST;
		tp->tty_iovir = (vir_bytes) m_ptr->ADDRESS;
		r = SUSPEND;
		break;
	}
	if (m_ptr->TTY_REQUEST == TCDRAIN) break;
	if (m_ptr->TTY_REQUEST == TCSETSF) tty_icancel(tp);
	/*FALL THROUGH*/
    case TCSETS:
	/* Set the termios attributes. */
	r = sys_vircopy( m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS,
		SELF, D, (vir_bytes) &tp->tty_termios, (vir_bytes) size);
	if (r != OK) break;
	setattr(tp);
	break;

    case TCFLSH:
	r = sys_vircopy( m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS,
		SELF, D, (vir_bytes) &param.i, (vir_bytes) size);
	if (r != OK) break;
	switch (param.i) {
	    case TCIFLUSH:	tty_icancel(tp);		 	    break;
	    case TCOFLUSH:	(*tp->tty_ocancel)(tp, 0);		    break;
	    case TCIOFLUSH:	tty_icancel(tp); (*tp->tty_ocancel)(tp, 0); break;
	    default:		r = EINVAL;
	}
	break;

    case TCFLOW:
	r = sys_vircopy( m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS,
		SELF, D, (vir_bytes) &param.i, (vir_bytes) size);
	if (r != OK) break;
	switch (param.i) {
	    case TCOOFF:
	    case TCOON:
		tp->tty_inhibited = (param.i == TCOOFF);
		tp->tty_events = 1;
		break;
	    case TCIOFF:
		(*tp->tty_echo)(tp, tp->tty_termios.c_cc[VSTOP]);
		break;
	    case TCION:
		(*tp->tty_echo)(tp, tp->tty_termios.c_cc[VSTART]);
		break;
	    default:
		r = EINVAL;
	}
	break;

    case TCSBRK:
	if (tp->tty_break != NULL) (*tp->tty_break)(tp,0);
	break;

    case TIOCGWINSZ:
	r = sys_vircopy(SELF, D, (vir_bytes) &tp->tty_winsize,
		m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS, 
		(vir_bytes) size);
	break;

    case TIOCSWINSZ:
	r = sys_vircopy( m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS,
		SELF, D, (vir_bytes) &tp->tty_winsize, (vir_bytes) size);
	sigchar(tp, SIGWINCH);
	break;

#if ENABLE_SRCCOMPAT
    case TIOCGETP:
	compat_getp(tp, &param.sg);
	r = sys_vircopy(SELF, D, (vir_bytes) &param.sg,
		m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS,
		(vir_bytes) size);
	break;

    case TIOCSETP:
	r = sys_vircopy( m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS,
		SELF, D, (vir_bytes) &param.sg, (vir_bytes) size);
	if (r != OK) break;
	compat_setp(tp, &param.sg);
	break;

    case TIOCGETC:
	compat_getc(tp, &param.tc);
	r = sys_vircopy(SELF, D, (vir_bytes) &param.tc,
		m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS, 
		(vir_bytes) size);
	break;

    case TIOCSETC:
	r = sys_vircopy( m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS,
		SELF, D, (vir_bytes) &param.tc, (vir_bytes) size);
	if (r != OK) break;
	compat_setc(tp, &param.tc);
	break;
#endif

#if (MACHINE == IBM_PC)
    case KIOCSMAP:
	/* Load a new keymap (only /dev/console). */
	if (isconsole(tp)) r = kbd_loadmap(m_ptr);
	break;

    case TIOCSFON:
	/* Load a font into an EGA or VGA card ([e-mail]) */
	if (isconsole(tp)) r = con_loadfont(m_ptr);
	break;
#endif

#if (MACHINE == ATARI)
    case VDU_LOADFONT:
	r = vdu_loadfont(m_ptr);
	break;
#endif

/* These Posix functions are allowed to fail if _POSIX_JOB_CONTROL is 
 * not defined.
 */
    case TIOCGPGRP:     
    case TIOCSPGRP:	
    default:
#if ENABLE_BINCOMPAT
	do_ioctl_compat(tp, m_ptr);
	return;
#else
	r = ENOTTY;
#endif
  }

  /* Send the reply. */
  tty_reply(TASK_REPLY, m_ptr->m_source, m_ptr->PROC_NR, r);
}

/*===========================================================================*
 *				do_open					     *
 *===========================================================================*/
PRIVATE void do_open(tp, m_ptr)
register tty_t *tp;
message *m_ptr;			/* pointer to message sent to task */
{
/* A tty line has been opened.  Make it the callers controlling tty if
 * O_NOCTTY is *not* set and it is not the log device.  1 is returned if
 * the tty is made the controlling tty, otherwise OK or an error code.
 */
  int r = OK;

  if (m_ptr->TTY_LINE == LOG_MINOR) {
	/* The log device is a write-only diagnostics device. */
	if (m_ptr->COUNT & R_BIT) r = EACCES;
  } else {
	if (!(m_ptr->COUNT & O_NOCTTY)) {
		tp->tty_pgrp = m_ptr->PROC_NR;
		r = 1;
	}
	tp->tty_openct++;
  }
  tty_reply(TASK_REPLY, m_ptr->m_source, m_ptr->PROC_NR, r);
}

/*===========================================================================*
 *				do_close				     *
 *===========================================================================*/
PRIVATE void do_close(tp, m_ptr)
register tty_t *tp;
message *m_ptr;			/* pointer to message sent to task */
{
/* A tty line has been closed.  Clean up the line if it is the last close. */

  if (m_ptr->TTY_LINE != LOG_MINOR && --tp->tty_openct == 0) {
	tp->tty_pgrp = 0;
	tty_icancel(tp);
	(*tp->tty_ocancel)(tp, 0);
	(*tp->tty_close)(tp, 0);
	tp->tty_termios = termios_defaults;
	tp->tty_winsize = winsize_defaults;
	setattr(tp);
  }
  tty_reply(TASK_REPLY, m_ptr->m_source, m_ptr->PROC_NR, OK);
}

/*===========================================================================*
 *				do_cancel				     *
 *===========================================================================*/
PRIVATE void do_cancel(tp, m_ptr)
register tty_t *tp;
message *m_ptr;			/* pointer to message sent to task */
{
/* A signal has been sent to a process that is hanging trying to read or write.
 * The pending read or write must be finished off immediately.
 */

  int proc_nr;
  int mode;

  /* Check the parameters carefully, to avoid cancelling twice. */
  proc_nr = m_ptr->PROC_NR;
  mode = m_ptr->COUNT;
  if ((mode & R_BIT) && tp->tty_inleft != 0 && proc_nr == tp->tty_inproc) {
	/* Process was reading when killed.  Clean up input. */
	tty_icancel(tp);
	tp->tty_inleft = tp->tty_incum = 0;
  }
  if ((mode & W_BIT) && tp->tty_outleft != 0 && proc_nr == tp->tty_outproc) {
	/* Process was writing when killed.  Clean up output. */
	(*tp->tty_ocancel)(tp, 0);
	tp->tty_outleft = tp->tty_outcum = 0;
  }
  if (tp->tty_ioreq != 0 && proc_nr == tp->tty_ioproc) {
	/* Process was waiting for output to drain. */
	tp->tty_ioreq = 0;
  }
  tp->tty_events = 1;
  tty_reply(TASK_REPLY, m_ptr->m_source, proc_nr, EINTR);
}

PUBLIC int select_try(struct tty *tp, int ops)
{
	int ready_ops = 0;

	/* Special case. If line is hung up, no operations will block.
	 * (and it can be seen as an exceptional condition.)
	 */
	if (tp->tty_termios.c_ospeed == B0) {
		ready_ops |= ops;
	}

	if (ops & SEL_RD) {
		/* will i/o not block on read? */
		if (tp->tty_inleft > 0) {
			ready_ops |= SEL_RD;	/* EIO - no blocking */
		} else if (tp->tty_incount > 0) {
			/* Is a regular read possible? tty_incount
			 * says there is data. But a read will only succeed
			 * in canonical mode if a newline has been seen.
			 */
			if (!(tp->tty_termios.c_lflag & ICANON) ||
				tp->tty_eotct > 0) {
				ready_ops |= SEL_RD;
			}
		}
	}

	if (ops & SEL_WR)  {
  		if (tp->tty_outleft > 0)  ready_ops |= SEL_WR;
		else if ((*tp->tty_devwrite)(tp, 1)) ready_ops |= SEL_WR;
	}

	return ready_ops;
}

PUBLIC int select_retry(struct tty *tp)
{
	if (select_try(tp, tp->tty_select_ops))
		notify(tp->tty_select_proc);
	return OK;
}

/*===========================================================================*
 *				handle_events				     *
 *===========================================================================*/
PUBLIC void handle_events(tp)
tty_t *tp;			/* TTY to check for events. */
{
/* Handle any events pending on a TTY.  These events are usually device
 * interrupts.
 *
 * Two kinds of events are prominent:
 *	- a character has been received from the console or an RS232 line.
 *	- an RS232 line has completed a write request (on behalf of a user).
 * The interrupt handler may delay the interrupt message at its discretion
 * to avoid swamping the TTY task.  Messages may be overwritten when the
 * lines are fast or when there are races between different lines, input
 * and output, because MINIX only provides single buffering for interrupt
 * messages (in proc.c).  This is handled by explicitly checking each line
 * for fresh input and completed output on each interrupt.
 */
  char *buf;
  unsigned count;
  int status;

  do {
	tp->tty_events = 0;

	/* Read input and perform input processing. */
	(*tp->tty_devread)(tp, 0);

	/* Perform output processing and write output. */
	(*tp->tty_devwrite)(tp, 0);

	/* Ioctl waiting for some event? */
	if (tp->tty_ioreq != 0) dev_ioctl(tp);
  } while (tp->tty_events);

  /* Transfer characters from the input queue to a waiting process. */
  in_transfer(tp);

  /* Reply if enough bytes are available. */
  if (tp->tty_incum >= tp->tty_min && tp->tty_inleft > 0) {
	if (tp->tty_inrepcode == REVIVE) {
		notify(tp->tty_incaller);
		tp->tty_inrevived = 1;
	} else {
		tty_reply(tp->tty_inrepcode, tp->tty_incaller, 
			tp->tty_inproc, tp->tty_incum);
		tp->tty_inleft = tp->tty_incum = 0;
	}
  }
  if (tp->tty_select_ops)
  	select_retry(tp);
#if NR_PTYS > 0
  if (ispty(tp))
  	select_retry_pty(tp);
#endif
}

/*===========================================================================*
 *				in_transfer				     *
 *===========================================================================*/
PRIVATE void in_transfer(tp)
register tty_t *tp;		/* pointer to terminal to read from */
{
/* Transfer bytes from the input queue to a process reading from a terminal. */

  int ch;
  int count;
  char buf[64], *bp;

  /* Force read to succeed if the line is hung up, looks like EOF to reader. */
  if (tp->tty_termios.c_ospeed == B0) tp->tty_min = 0;

  /* Anything to do? */
  if (tp->tty_inleft == 0 || tp->tty_eotct < tp->tty_min) return;

  bp = buf;
  while (tp->tty_inleft > 0 && tp->tty_eotct > 0) {
	ch = *tp->tty_intail;

	if (!(ch & IN_EOF)) {
		/* One character to be delivered to the user. */
		*bp = ch & IN_CHAR;
		tp->tty_inleft--;
		if (++bp == bufend(buf)) {
			/* Temp buffer full, copy to user space. */
			sys_vircopy(SELF, D, (vir_bytes) buf, 
				tp->tty_inproc, D, tp->tty_in_vir,
				(vir_bytes) buflen(buf));
			tp->tty_in_vir += buflen(buf);
			tp->tty_incum += buflen(buf);
			bp = buf;
		}
	}

	/* Remove the character from the input queue. */
	if (++tp->tty_intail == bufend(tp->tty_inbuf))
		tp->tty_intail = tp->tty_inbuf;
	tp->tty_incount--;
	if (ch & IN_EOT) {
		tp->tty_eotct--;
		/* Don't read past a line break in canonical mode. */
		if (tp->tty_termios.c_lflag & ICANON) tp->tty_inleft = 0;
	}
  }

  if (bp > buf) {
	/* Leftover characters in the buffer. */
	count = bp - buf;
	sys_vircopy(SELF, D, (vir_bytes) buf, 
		tp->tty_inproc, D, tp->tty_in_vir, (vir_bytes) count);
	tp->tty_in_vir += count;
	tp->tty_incum += count;
  }

  /* Usually reply to the reader, possibly even if incum == 0 (EOF). */
  if (tp->tty_inleft == 0) {
	if (tp->tty_inrepcode == REVIVE) {
		notify(tp->tty_incaller);
		tp->tty_inrevived = 1;
	} else {
		tty_reply(tp->tty_inrepcode, tp->tty_incaller, 
			tp->tty_inproc, tp->tty_incum);
		tp->tty_inleft = tp->tty_incum = 0;
	}
  }
}

/*===========================================================================*
 *				in_process				     *
 *===========================================================================*/
PUBLIC int in_process(tp, buf, count)
register tty_t *tp;		/* terminal on which character has arrived */
char *buf;			/* buffer with input characters */
int count;			/* number of input characters */
{
/* Characters have just been typed in.  Process, save, and echo them.  Return
 * the number of characters processed.
 */

  int ch, sig, ct;
  int timeset = FALSE;
  static unsigned char csize_mask[] = { 0x1F, 0x3F, 0x7F, 0xFF };

  for (ct = 0; ct < count; ct++) {
	/* Take one character. */
	ch = *buf++ & BYTE;

	/* Strip to seven bits? */
	if (tp->tty_termios.c_iflag & ISTRIP) ch &= 0x7F;

	/* Input extensions? */
	if (tp->tty_termios.c_lflag & IEXTEN) {