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。]

/* This file contains the terminal driver, both for the IBM console and regular
 * ASCII terminals.  It handles only the device-independent part of a TTY, the
 * device dependent parts are in console.c, rs232.c, etc.  This file contains
 * two main entry points, tty_task() and tty_wakeup(), and several minor entry
 * points for use by the device-dependent code.
 *
 * The device-independent part accepts "keyboard" input from the device-
 * dependent part, performs input processing (special key interpretation),
 * and sends the input to a process reading from the TTY.  Output to a TTY
 * is sent to the device-dependent code for output processing and "screen"
 * display.  Input processing is done by the device by calling 'in_process'
 * on the input characters, output processing may be done by the device itself
 * or by calling 'out_process'.  The TTY takes care of input queuing, the
 * device does the output queuing.  If a device receives an external signal,
 * like an interrupt, then it causes tty_wakeup() to be run by the CLOCK task
 * to, you guessed it, wake up the TTY to check if input or output can
 * continue.
 *
 * The valid messages and their parameters are:
 *
 *   HARD_INT:       output has been completed or input has arrived
 *   SYS_SIG:      e.g., MINIX wants to shutdown; run code to cleanly stop
 *   DEV_READ:       a process wants to read from a terminal
 *   DEV_WRITE:      a process wants to write on a terminal
 *   DEV_IOCTL:      a process wants to change a terminal's parameters
 *   DEV_OPEN:       a tty line has been opened
 *   DEV_CLOSE:      a tty line has been closed
 *   DEV_SELECT:     start select notification request
 *   DEV_STATUS:     FS wants to know status for SELECT or REVIVE
 *   CANCEL:         terminate a previous incomplete system call immediately
 *
 *    m_type      TTY_LINE   PROC_NR    COUNT   TTY_SPEK  TTY_FLAGS  ADDRESS
 * ---------------------------------------------------------------------------
 * | HARD_INT    |         |         |         |         |         |         |
 * |-------------+---------+---------+---------+---------+---------+---------|
 * | SYS_SIG     | sig set |         |         |         |         |         |
 * |-------------+---------+---------+---------+---------+---------+---------|
 * | DEV_READ    |minor dev| proc nr |  count  |         O_NONBLOCK| buf ptr |
 * |-------------+---------+---------+---------+---------+---------+---------|
 * | DEV_WRITE   |minor dev| proc nr |  count  |         |         | buf ptr |
 * |-------------+---------+---------+---------+---------+---------+---------|
 * | DEV_IOCTL   |minor dev| proc nr |func code|erase etc|  flags  |         |
 * |-------------+---------+---------+---------+---------+---------+---------|
 * | DEV_OPEN    |minor dev| proc nr | O_NOCTTY|         |         |         |
 * |-------------+---------+---------+---------+---------+---------+---------|
 * | DEV_CLOSE   |minor dev| proc nr |         |         |         |         |
 * |-------------+---------+---------+---------+---------+---------+---------|
 * | DEV_SELECT  |         |         |         |         |         |         |
 * |-------------+---------+---------+---------+---------+---------+---------|
 * | DEV_STATUS  |         |         |         |         |         |         |
 * |-------------+---------+---------+---------+---------+---------+---------|
 * | CANCEL      |minor dev| proc nr |         |         |         |         |
 * ---------------------------------------------------------------------------
 *
 * Changes:
 *   Jan 20, 2004   moved TTY driver to user-space  (Jorrit N. Herder)
 *   Sep 20, 2004   local timer management/ sync alarms  (Jorrit N. Herder)
 *   Jul 13, 2004   support for function key observers  (Jorrit N. Herder)  
 */

#include "../drivers.h"
#include <termios.h>
#if ENABLE_SRCCOMPAT || ENABLE_BINCOMPAT
#include <sgtty.h>
#endif
#include <sys/ioc_tty.h>
#include <signal.h>
#include <minix/callnr.h>
#if (CHIP == INTEL)
#include <minix/keymap.h>
#endif
#include "tty.h"

#include <sys/time.h>
#include <sys/select.h>

extern int irq_hook_id;

unsigned long kbd_irq_set = 0;
unsigned long rs_irq_set = 0;

/* Address of a tty structure. */
#define tty_addr(line)	(&tty_table[line])

/* Macros for magic tty types. */
#define isconsole(tp)	((tp) < tty_addr(NR_CONS))
#define ispty(tp)	((tp) >= tty_addr(NR_CONS+NR_RS_LINES))

/* Macros for magic tty structure pointers. */
#define FIRST_TTY	tty_addr(0)
#define END_TTY		tty_addr(sizeof(tty_table) / sizeof(tty_table[0]))

/* A device exists if at least its 'devread' function is defined. */
#define tty_active(tp)	((tp)->tty_devread != NULL)

/* RS232 lines or pseudo terminals can be completely configured out. */
#if NR_RS_LINES == 0
#define rs_init(tp)	((void) 0)
#endif
#if NR_PTYS == 0
#define pty_init(tp)	((void) 0)
#define do_pty(tp, mp)	((void) 0)
#endif

struct kmessages kmess;

FORWARD _PROTOTYPE( void tty_timed_out, (timer_t *tp)			);
FORWARD _PROTOTYPE( void expire_timers, (void)				);
FORWARD _PROTOTYPE( void settimer, (tty_t *tty_ptr, int enable)		);
FORWARD _PROTOTYPE( void do_cancel, (tty_t *tp, message *m_ptr)		);
FORWARD _PROTOTYPE( void do_ioctl, (tty_t *tp, message *m_ptr)		);
FORWARD _PROTOTYPE( void do_open, (tty_t *tp, message *m_ptr)		);
FORWARD _PROTOTYPE( void do_close, (tty_t *tp, message *m_ptr)		);
FORWARD _PROTOTYPE( void do_read, (tty_t *tp, message *m_ptr)		);
FORWARD _PROTOTYPE( void do_write, (tty_t *tp, message *m_ptr)		);
FORWARD _PROTOTYPE( void do_select, (tty_t *tp, message *m_ptr)		);
FORWARD _PROTOTYPE( void do_status, (message *m_ptr)			);
FORWARD _PROTOTYPE( void in_transfer, (tty_t *tp)			);
FORWARD _PROTOTYPE( int tty_echo, (tty_t *tp, int ch)			);
FORWARD _PROTOTYPE( void rawecho, (tty_t *tp, int ch)			);
FORWARD _PROTOTYPE( int back_over, (tty_t *tp)				);
FORWARD _PROTOTYPE( void reprint, (tty_t *tp)				);
FORWARD _PROTOTYPE( void dev_ioctl, (tty_t *tp)				);
FORWARD _PROTOTYPE( void setattr, (tty_t *tp)				);
FORWARD _PROTOTYPE( void tty_icancel, (tty_t *tp)			);
FORWARD _PROTOTYPE( void tty_init, (void)				);
#if ENABLE_SRCCOMPAT || ENABLE_BINCOMPAT
FORWARD _PROTOTYPE( int compat_getp, (tty_t *tp, struct sgttyb *sg)	);
FORWARD _PROTOTYPE( int compat_getc, (tty_t *tp, struct tchars *sg)	);
FORWARD _PROTOTYPE( int compat_setp, (tty_t *tp, struct sgttyb *sg)	);
FORWARD _PROTOTYPE( int compat_setc, (tty_t *tp, struct tchars *sg)	);
FORWARD _PROTOTYPE( int tspd2sgspd, (speed_t tspd)			);
FORWARD _PROTOTYPE( speed_t sgspd2tspd, (int sgspd)			);
#if ENABLE_BINCOMPAT
FORWARD _PROTOTYPE( void do_ioctl_compat, (tty_t *tp, message *m_ptr)	);
#endif
#endif

/* Default attributes. */
PRIVATE struct termios termios_defaults = {
  TINPUT_DEF, TOUTPUT_DEF, TCTRL_DEF, TLOCAL_DEF, TSPEED_DEF, TSPEED_DEF,
  {
	TEOF_DEF, TEOL_DEF, TERASE_DEF, TINTR_DEF, TKILL_DEF, TMIN_DEF,
	TQUIT_DEF, TTIME_DEF, TSUSP_DEF, TSTART_DEF, TSTOP_DEF,
	TREPRINT_DEF, TLNEXT_DEF, TDISCARD_DEF,
  },
};
PRIVATE struct winsize winsize_defaults;	/* = all zeroes */

/* Global variables for the TTY task (declared extern in tty.h). */
PUBLIC tty_t tty_table[NR_CONS+NR_RS_LINES+NR_PTYS];
PUBLIC int ccurrent;			/* currently active console */
PUBLIC timer_t *tty_timers;		/* queue of TTY timers */
PUBLIC clock_t tty_next_timeout;	/* time that the next alarm is due */
PUBLIC struct machine machine;		/* kernel environment variables */

/*===========================================================================*
 *				tty_task				     *
 *===========================================================================*/
PUBLIC void main(void)
{
/* Main routine of the terminal task. */

  message tty_mess;		/* buffer for all incoming messages */
  unsigned line;
  int r, s;
  register struct proc *rp;
  register tty_t *tp;

  /* Initialize the TTY driver. */
  tty_init();

  /* Get kernel environment (protected_mode, pc_at and ega are needed). */ 
  if (OK != (s=sys_getmachine(&machine))) {
    panic("TTY","Couldn't obtain kernel environment.", s);
  }

  /* Final one-time keyboard initialization. */
  kb_init_once();

  printf("\n");

  while (TRUE) {

	/* Check for and handle any events on any of the ttys. */
	for (tp = FIRST_TTY; tp < END_TTY; tp++) {
		if (tp->tty_events) handle_events(tp);
	}

	/* Get a request message. */
	r= receive(ANY, &tty_mess);
	if (r != 0)
		panic("TTY", "receive failed with %d", r);

	/* First handle all kernel notification types that the TTY supports. 
	 *  - An alarm went off, expire all timers and handle the events. 
	 *  - A hardware interrupt also is an invitation to check for events. 
	 *  - A new kernel message is available for printing.
	 *  - Reset the console on system shutdown. 
	 * Then see if this message is different from a normal device driver
	 * request and should be handled separately. These extra functions
	 * do not operate on a device, in constrast to the driver requests. 
	 */
	switch (tty_mess.m_type) { 
	case SYN_ALARM: 		/* fall through */
		expire_timers();	/* run watchdogs of expired timers */
		continue;		/* contine to check for events */
	case DEV_PING:
		notify(tty_mess.m_source);
		continue;
	case HARD_INT: {		/* hardware interrupt notification */
		if (tty_mess.NOTIFY_ARG & kbd_irq_set)
			kbd_interrupt(&tty_mess);/* fetch chars from keyboard */
#if NR_RS_LINES > 0
		if (tty_mess.NOTIFY_ARG & rs_irq_set)
			rs_interrupt(&tty_mess);/* serial I/O */
#endif
		expire_timers();	/* run watchdogs of expired timers */
		continue;		/* contine to check for events */
	}
	case SYS_SIG: {			/* system signal */
		sigset_t sigset = (sigset_t) tty_mess.NOTIFY_ARG;

		if (sigismember(&sigset, SIGKSTOP)) {
			cons_stop();		/* switch to primary console */
			if (irq_hook_id != -1) {
				sys_irqdisable(&irq_hook_id);
				sys_irqrmpolicy(KEYBOARD_IRQ, &irq_hook_id);
			}
		} 
		if (sigismember(&sigset, SIGTERM)) cons_stop();	
		if (sigismember(&sigset, SIGKMESS)) do_new_kmess(&tty_mess);
		continue;
	}
	case PANIC_DUMPS:		/* allow panic dumps */
		cons_stop();		/* switch to primary console */
		do_panic_dumps(&tty_mess);	
		continue;
	case DIAGNOSTICS: 		/* a server wants to print some */
		do_diagnostics(&tty_mess);
		continue;
	case GET_KMESS:
		do_get_kmess(&tty_mess);
		continue;
	case FKEY_CONTROL:		/* (un)register a fkey observer */
		do_fkey_ctl(&tty_mess);
		continue;
	default:			/* should be a driver request */
		;			/* do nothing; end switch */
	}

	/* Only device requests should get to this point. All requests, 
	 * except DEV_STATUS, have a minor device number. Check this
	 * exception and get the minor device number otherwise.
	 */
	if (tty_mess.m_type == DEV_STATUS) {
		do_status(&tty_mess);
		continue;
	}
	line = tty_mess.TTY_LINE;
	if ((line - CONS_MINOR) < NR_CONS) {
		tp = tty_addr(line - CONS_MINOR);
	} else if (line == LOG_MINOR) {
		tp = tty_addr(0);
	} else if ((line - RS232_MINOR) < NR_RS_LINES) {
		tp = tty_addr(line - RS232_MINOR + NR_CONS);
	} else if ((line - TTYPX_MINOR) < NR_PTYS) {
		tp = tty_addr(line - TTYPX_MINOR + NR_CONS + NR_RS_LINES);
	} else if ((line - PTYPX_MINOR) < NR_PTYS) {
		tp = tty_addr(line - PTYPX_MINOR + NR_CONS + NR_RS_LINES);
		if (tty_mess.m_type != DEV_IOCTL) {
			do_pty(tp, &tty_mess);
			continue;
		}
	} else {
		tp = NULL;
	}

	/* If the device doesn't exist or is not configured return ENXIO. */
	if (tp == NULL || ! tty_active(tp)) {
		printf("Warning, TTY got illegal request %d from %d\n",
			tty_mess.m_type, tty_mess.m_source);
		if (tty_mess.m_source != LOG_PROC_NR)
		{
			tty_reply(TASK_REPLY, tty_mess.m_source,
						tty_mess.PROC_NR, ENXIO);
		}
		continue;
	}

	/* Execute the requested device driver function. */
	switch (tty_mess.m_type) {
	    case DEV_READ:	 do_read(tp, &tty_mess);	  break;
	    case DEV_WRITE:	 do_write(tp, &tty_mess);	  break;
	    case DEV_IOCTL:	 do_ioctl(tp, &tty_mess);	  break;
	    case DEV_OPEN:	 do_open(tp, &tty_mess);	  break;
	    case DEV_CLOSE:	 do_close(tp, &tty_mess);	  break;
	    case DEV_SELECT:	 do_select(tp, &tty_mess);	  break;
	    case CANCEL:	 do_cancel(tp, &tty_mess);	  break;
	    default:		
		printf("Warning, TTY got unexpected request %d from %d\n",
			tty_mess.m_type, tty_mess.m_source);
	    tty_reply(TASK_REPLY, tty_mess.m_source,
						tty_mess.PROC_NR, EINVAL);
	}
  }
}

/*===========================================================================*
 *				do_status				     *
 *===========================================================================*/
PRIVATE void do_status(m_ptr)
message *m_ptr;
{
  register struct tty *tp;
  int event_found;
  int status;
  int ops;
  
  /* Check for select or revive events on any of the ttys. If we found an, 
   * event return a single status message for it. The FS will make another 
   * call to see if there is more.
   */
  event_found = 0;
  for (tp = FIRST_TTY; tp < END_TTY; tp++) {
	if ((ops = select_try(tp, tp->tty_select_ops)) && 
			tp->tty_select_proc == m_ptr->m_source) {

		/* I/O for a selected minor device is ready. */
		m_ptr->m_type = DEV_IO_READY;
		m_ptr->DEV_MINOR = tp->tty_minor;
		m_ptr->DEV_SEL_OPS = ops;

		tp->tty_select_ops &= ~ops;	/* unmark select event */
  		event_found = 1;
		break;
	}
	else if (tp->tty_inrevived && tp->tty_incaller == m_ptr->m_source) {
		
		/* Suspended request finished. Send a REVIVE. */
		m_ptr->m_type = DEV_REVIVE;
  		m_ptr->REP_PROC_NR = tp->tty_inproc;
  		m_ptr->REP_STATUS = tp->tty_incum;

		tp->tty_inleft = tp->tty_incum = 0;
		tp->tty_inrevived = 0;		/* unmark revive event */
  		event_found = 1;
  		break;
	}
	else if (tp->tty_outrevived && tp->tty_outcaller == m_ptr->m_source) {
		
		/* Suspended request finished. Send a REVIVE. */
		m_ptr->m_type = DEV_REVIVE;
  		m_ptr->REP_PROC_NR = tp->tty_outproc;
  		m_ptr->REP_STATUS = tp->tty_outcum;

		tp->tty_outcum = 0;
		tp->tty_outrevived = 0;		/* unmark revive event */
  		event_found = 1;
  		break;
	}
  }

#if NR_PTYS > 0
  if (!event_found)
  	event_found = pty_status(m_ptr);
#endif

  if (! event_found) {
	/* No events of interest were found. Return an empty message. */
  	m_ptr->m_type = DEV_NO_STATUS;
  }

  /* Almost done. Send back the reply message to the caller. */
  if ((status = send(m_ptr->m_source, m_ptr)) != OK) {
	panic("TTY","send in do_status failed, status\n", status);
  }
}

/*===========================================================================*
 *				do_read					     *
 *===========================================================================*/
PRIVATE void do_read(tp, m_ptr)
register tty_t *tp;		/* pointer to tty struct */
register message *m_ptr;	/* pointer to message sent to the task */
{
/* A process wants to read from a terminal. */
  int r, status;
  phys_bytes phys_addr;

  /* Check if there is already a process hanging in a read, check if the
   * parameters are correct, do I/O.
   */
  if (tp->tty_inleft > 0) {
	r = EIO;
  } else
  if (m_ptr->COUNT <= 0) {
	r = EINVAL;
  } else
  if (sys_umap(m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS, m_ptr->COUNT,
		&phys_addr) != OK) {
	r = EFAULT;
  } else {
	/* Copy information from the message to the tty struct. */
	tp->tty_inrepcode = TASK_REPLY;
	tp->tty_incaller = m_ptr->m_source;
	tp->tty_inproc = m_ptr->PROC_NR;
	tp->tty_in_vir = (vir_bytes) m_ptr->ADDRESS;
	tp->tty_inleft = m_ptr->COUNT;

	if (!(tp->tty_termios.c_lflag & ICANON)
					&& tp->tty_termios.c_cc[VTIME] > 0) {
		if (tp->tty_termios.c_cc[VMIN] == 0) {
			/* MIN & TIME specify a read timer that finishes the
			 * read in TIME/10 seconds if no bytes are available.
			 */
			settimer(tp, TRUE);
			tp->tty_min = 1;
		} else {
			/* MIN & TIME specify an inter-byte timer that may
			 * have to be cancelled if there are no bytes yet.
			 */
			if (tp->tty_eotct == 0) {
				settimer(tp, FALSE);
				tp->tty_min = tp->tty_termios.c_cc[VMIN];
			}
		}
	}

	/* Anything waiting in the input buffer? Clear it out... */
	in_transfer(tp);
	/* ...then go back for more. */
	handle_events(tp);
	if (tp->tty_inleft == 0)  {
  		if (tp->tty_select_ops)
  			select_retry(tp);
		return;			/* already done */
	}

	/* There were no bytes in the input queue available, so either suspend
	 * the caller or break off the read if nonblocking.
	 */
	if (m_ptr->TTY_FLAGS & O_NONBLOCK) {
		r = EAGAIN;				/* cancel the read */
		tp->tty_inleft = tp->tty_incum = 0;
	} else {
		r = SUSPEND;				/* suspend the caller */
		tp->tty_inrepcode = REVIVE;
	}
  }
  tty_reply(TASK_REPLY, m_ptr->m_source, m_ptr->PROC_NR, r);
  if (tp->tty_select_ops)
  	select_retry(tp);
}

/*===========================================================================*
 *				do_write				     *
 *===========================================================================*/
PRIVATE void do_write(tp, m_ptr)
register tty_t *tp;
register message *m_ptr;	/* pointer to message sent to the task */
{
/* A process wants to write on a terminal. */
  int r;
  phys_bytes phys_addr;

  /* Check if there is already a process hanging in a write, check if the
   * parameters are correct, do I/O.
   */
  if (tp->tty_outleft > 0) {
	r = EIO;
  } else
  if (m_ptr->COUNT <= 0) {
	r = EINVAL;
  } else
  if (sys_umap(m_ptr->PROC_NR, D, (vir_bytes) m_ptr->ADDRESS, m_ptr->COUNT,
		&phys_addr) != OK) {
	r = EFAULT;
  } else {
	/* Copy message parameters to the tty structure. */
	tp->tty_outrepcode = TASK_REPLY;
	tp->tty_outcaller = m_ptr->m_source;
	tp->tty_outproc = m_ptr->PROC_NR;
	tp->tty_out_vir = (vir_bytes) m_ptr->ADDRESS;
	tp->tty_outleft = m_ptr->COUNT;

	/* Try to write. */
	handle_events(tp);
	if (tp->tty_outleft == 0) 
		return;	/* already done */

	/* None or not all the bytes could be written, so either suspend the
	 * caller or break off the write if nonblocking.
	 */
	if (m_ptr->TTY_FLAGS & O_NONBLOCK) {		/* cancel the write */
		r = tp->tty_outcum > 0 ? tp->tty_outcum : EAGAIN;
		tp->tty_outleft = tp->tty_outcum = 0;
	} else {
		r = SUSPEND;				/* suspend the caller */