Import 2.1.15

[davej-history.git] / drivers / char / tty_io.c

/*
 * linux/drivers/char/tty_io.c
 *
 * Copyright (C) 1991, 1992 Linus Torvalds
 */

/*
 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
 * or rs-channels. It also implements echoing, cooked mode etc.
 *
 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
 *
 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
 * tty_struct and tty_queue structures. Previously there was an array
 * of 256 tty_struct's which was statically allocated, and the
 * tty_queue structures were allocated at boot time. Both are now
 * dynamically allocated only when the tty is open.
 *
 * Also restructured routines so that there is more of a separation
 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
 * the low-level tty routines (serial.c, pty.c, console.c). This
 * makes for cleaner and more compact code. -TYT, 9/17/92 
 *
 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
 * which can be dynamically activated and de-activated by the line
 * discipline handling modules (like SLIP).
 *
 * NOTE: pay no attention to the line discipline code (yet); its
 * interface is still subject to change in this version...
 * -- TYT, 1/31/92
 *
 * Added functionality to the OPOST tty handling. No delays, but all
 * other bits should be there.
 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
 *
 * Rewrote canonical mode and added more termios flags.
 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
 *
 * Reorganized FASYNC support so mouse code can share it.
 * -- ctm@ardi.com, 9Sep95
 *
 * New TIOCLINUX variants added.
 * -- mj@k332.feld.cvut.cz, 19-Nov-95
 * 
 * Restrict vt switching via ioctl()
 * -- grif@cs.ucr.edu, 5-Dec-95
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/fcntl.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/timer.h>
#include <linux/ctype.h>
#include <linux/kd.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/malloc.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/bitops.h>

#include"kbd_kern.h"
#include"vt_kern.h"
#include"selection.h"

#ifdef CONFIG_KERNELD
#include <linux/kerneld.h>
#endif

#define CONSOLE_DEV MKDEV(TTY_MAJOR,0)
#define TTY_DEV MKDEV(TTYAUX_MAJOR,0)

#undef TTY_DEBUG_HANGUP

#define TTY_PARANOIA_CHECK
#define CHECK_TTY_COUNT

externvoiddo_blank_screen(int nopowersave);
externvoidset_vesa_blanking(const unsigned long arg);

struct termios tty_std_termios;/* for the benefit of tty drivers */
struct tty_driver *tty_drivers = NULL;/* linked list of tty drivers */
struct tty_ldisc ldiscs[NR_LDISCS];/* line disc dispatch table */

/*
 * fg_console is the current virtual console,
 * last_console is the last used one,
 * want_console is the console we want to switch to,
 * kmsg_redirect is the console for kernel messages,
 * redirect is the pseudo-tty that console output
 * is redirected to if asked by TIOCCONS.
 */
int fg_console =0;
int last_console =0;
int want_console = -1;
int kmsg_redirect =0;
struct tty_struct * redirect = NULL;
struct wait_queue * keypress_wait = NULL;
char vt_dont_switch =0;

static voidinitialize_tty_struct(struct tty_struct *tty);

static longtty_read(struct inode *,struct file *,char*,unsigned long);
static longtty_write(struct inode *,struct file *,const char*,unsigned long);
static inttty_select(struct inode *,struct file *,int, select_table *);
static inttty_open(struct inode *,struct file *);
static voidtty_release(struct inode *,struct file *);
static inttty_ioctl(struct inode * inode,struct file * file,
unsigned int cmd,unsigned long arg);
static inttty_fasync(struct inode * inode,struct file * filp,int on);

externvoidreset_palette(int currcons) ;
externvoidset_palette(void) ;

#ifndef MIN
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif

/*
 * These two routines return the name of tty. tty_name() should NOT
 * be used in interrupt drivers, since it's not re-entrant. Use
 * _tty_name() instead.
 */
char*_tty_name(struct tty_struct *tty,char*buf)
{
if(tty)
sprintf(buf,"%s%d", tty->driver.name,
MINOR(tty->device) - tty->driver.minor_start +
 tty->driver.name_base);
else
strcpy(buf,"NULL tty");
return buf;
}

char*tty_name(struct tty_struct *tty)
{
static char buf[64];

return(_tty_name(tty, buf));
}

inlineinttty_paranoia_check(struct tty_struct *tty, kdev_t device,
const char*routine)
{
#ifdef TTY_PARANOIA_CHECK
static const char*badmagic =
"Warning: bad magic number for tty struct (%s) in %s\n";
static const char*badtty =
"Warning: null TTY for (%s) in %s\n";

if(!tty) {
printk(badtty,kdevname(device), routine);
return1;
}
if(tty->magic != TTY_MAGIC) {
printk(badmagic,kdevname(device), routine);
return1;
}
#endif
return0;
}

static intcheck_tty_count(struct tty_struct *tty,const char*routine)
{
#ifdef CHECK_TTY_COUNT
struct file *f;
int i, count =0;

for(f = first_file, i=0; i<nr_files; i++, f = f->f_next) {
if(!f->f_count)
continue;
if(f->private_data == tty) {
 count++;
}
}
if(tty->driver.type == TTY_DRIVER_TYPE_PTY &&
 tty->driver.subtype == PTY_TYPE_SLAVE &&
 tty->link && tty->link->count)
 count++;
if(tty->count != count) {
printk("Warning: dev (%s) tty->count(%d) != #fd's(%d) in %s\n",
kdevname(tty->device), tty->count, count, routine);
return count;
}
#endif
return0;
}

inttty_register_ldisc(int disc,struct tty_ldisc *new_ldisc)
{
if(disc < N_TTY || disc >= NR_LDISCS)
return-EINVAL;

if(new_ldisc) {
 ldiscs[disc] = *new_ldisc;
 ldiscs[disc].flags |= LDISC_FLAG_DEFINED;
 ldiscs[disc].num = disc;
}else
memset(&ldiscs[disc],0,sizeof(struct tty_ldisc));

return0;
}

/* Set the discipline of a tty line. */
static inttty_set_ldisc(struct tty_struct *tty,int ldisc)
{
int retval =0;
struct tty_ldisc o_ldisc;

if((ldisc < N_TTY) || (ldisc >= NR_LDISCS))
return-EINVAL;
#ifdef CONFIG_KERNELD
/* Eduardo Blanco <ejbs@cs.cs.com.uy> */
if(!(ldiscs[ldisc].flags & LDISC_FLAG_DEFINED)) {
char modname [20];
sprintf(modname,"tty-ldisc-%d", ldisc);
request_module(modname);
}
#endif
if(!(ldiscs[ldisc].flags & LDISC_FLAG_DEFINED))
return-EINVAL;

if(tty->ldisc.num == ldisc)
return0;/* We are already in the desired discipline */
 o_ldisc = tty->ldisc;

tty_wait_until_sent(tty,0);

/* Shutdown the current discipline. */
if(tty->ldisc.close)
(tty->ldisc.close)(tty);

/* Now set up the new line discipline. */
 tty->ldisc = ldiscs[ldisc];
 tty->termios->c_line = ldisc;
if(tty->ldisc.open)
 retval = (tty->ldisc.open)(tty);
if(retval <0) {
 tty->ldisc = o_ldisc;
 tty->termios->c_line = tty->ldisc.num;
if(tty->ldisc.open && (tty->ldisc.open(tty) <0)) {
 tty->ldisc = ldiscs[N_TTY];
 tty->termios->c_line = N_TTY;
if(tty->ldisc.open) {
int r = tty->ldisc.open(tty);

if(r <0)
panic("Couldn't open N_TTY ldisc for "
"%s --- error %d.",
tty_name(tty), r);
}
}
}
if(tty->ldisc.num != o_ldisc.num && tty->driver.set_ldisc)
 tty->driver.set_ldisc(tty);
return retval;
}

/*
 * This routine returns a tty driver structure, given a device number
 */
struct tty_driver *get_tty_driver(kdev_t device)
{
int major, minor;
struct tty_driver *p;

 minor =MINOR(device);
 major =MAJOR(device);

for(p = tty_drivers; p; p = p->next) {
if(p->major != major)
continue;
if(minor < p->minor_start)
continue;
if(minor >= p->minor_start + p->num)
continue;
return p;
}
return NULL;
}

/*
 * If we try to write to, or set the state of, a terminal and we're
 * not in the foreground, send a SIGTTOU. If the signal is blocked or
 * ignored, go ahead and perform the operation. (POSIX 7.2)
 */
inttty_check_change(struct tty_struct * tty)
{
if(current->tty != tty)
return0;
if(tty->pgrp <=0) {
printk("tty_check_change: tty->pgrp <= 0!\n");
return0;
}
if(current->pgrp == tty->pgrp)
return0;
if(is_ignored(SIGTTOU))
return0;
if(is_orphaned_pgrp(current->pgrp))
return-EIO;
(void)kill_pg(current->pgrp,SIGTTOU,1);
return-ERESTARTSYS;
}

static longhung_up_tty_read(struct inode * inode,struct file * file,
char* buf,unsigned long count)
{
return0;
}

static longhung_up_tty_write(struct inode * inode,
struct file * file,const char* buf,unsigned long count)
{
return-EIO;
}

static inthung_up_tty_select(struct inode * inode,struct file * filp,
int sel_type, select_table * wait)
{
return1;
}

static inthung_up_tty_ioctl(struct inode * inode,struct file * file,
unsigned int cmd,unsigned long arg)
{
return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
}

static long longtty_lseek(struct inode * inode,struct file * file,
long long offset,int orig)
{
return-ESPIPE;
}

static struct file_operations tty_fops = {
 tty_lseek,
 tty_read,
 tty_write,
 NULL,/* tty_readdir */
 tty_select,
 tty_ioctl,
 NULL,/* tty_mmap */
 tty_open,
 tty_release,
 NULL,/* tty_fsync */
 tty_fasync
};

static struct file_operations hung_up_tty_fops = {
 tty_lseek,
 hung_up_tty_read,
 hung_up_tty_write,
 NULL,/* hung_up_tty_readdir */
 hung_up_tty_select,
 hung_up_tty_ioctl,
 NULL,/* hung_up_tty_mmap */
 NULL,/* hung_up_tty_open */
 tty_release,/* hung_up_tty_release */
 NULL,/* hung_up_tty_fsync */
 NULL /* hung_up_tty_fasync */
};

voiddo_tty_hangup(struct tty_struct * tty,struct file_operations *fops)
{
int i;
struct file * filp;
struct task_struct *p;

if(!tty)
return;
check_tty_count(tty,"do_tty_hangup");
for(filp = first_file, i=0; i<nr_files; i++, filp = filp->f_next) {
if(!filp->f_count)
continue;
if(filp->private_data != tty)
continue;
if(!filp->f_inode)
continue;
if(filp->f_inode->i_rdev == CONSOLE_DEV)
continue;
if(filp->f_op != &tty_fops)
continue;
tty_fasync(filp->f_inode, filp,0);
 filp->f_op = fops;
}

if(tty->ldisc.flush_buffer)
 tty->ldisc.flush_buffer(tty);
if(tty->driver.flush_buffer)
 tty->driver.flush_buffer(tty);
if((tty->flags & (1<< TTY_DO_WRITE_WAKEUP)) &&
 tty->ldisc.write_wakeup)
(tty->ldisc.write_wakeup)(tty);
wake_up_interruptible(&tty->write_wait);
wake_up_interruptible(&tty->read_wait);

/*
 * Shutdown the current line discipline, and reset it to
 * N_TTY.
 */
if(tty->ldisc.num != ldiscs[N_TTY].num) {
if(tty->ldisc.close)
(tty->ldisc.close)(tty);
 tty->ldisc = ldiscs[N_TTY];
 tty->termios->c_line = N_TTY;
if(tty->ldisc.open) {
 i = (tty->ldisc.open)(tty);
if(i <0)
printk("do_tty_hangup: N_TTY open: error %d\n",
-i);
}
}

for_each_task(p) {
if((tty->session >0) && (p->session == tty->session) &&
 p->leader) {
send_sig(SIGHUP,p,1);
send_sig(SIGCONT,p,1);
if(tty->pgrp >0)
 p->tty_old_pgrp = tty->pgrp;
}
if(p->tty == tty)
 p->tty = NULL;
}
 tty->flags =0;
 tty->session =0;
 tty->pgrp = -1;
 tty->ctrl_status =0;
if(tty->driver.flags & TTY_DRIVER_RESET_TERMIOS)
*tty->termios = tty->driver.init_termios;
if(tty->driver.hangup)
(tty->driver.hangup)(tty);
}

voidtty_hangup(struct tty_struct * tty)
{
#ifdef TTY_DEBUG_HANGUP
printk("%s hangup...\n",tty_name(tty));
#endif
do_tty_hangup(tty, &hung_up_tty_fops);
}

voidtty_vhangup(struct tty_struct * tty)
{
#ifdef TTY_DEBUG_HANGUP
printk("%s vhangup...\n",tty_name(tty));
#endif
do_tty_hangup(tty, &hung_up_tty_fops);
}

inttty_hung_up_p(struct file * filp)
{
return(filp->f_op == &hung_up_tty_fops);
}

/*
 * This function is typically called only by the session leader, when
 * it wants to disassociate itself from its controlling tty.
 *
 * It performs the following functions:
 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
 * (2) Clears the tty from being controlling the session
 * (3) Clears the controlling tty for all processes in the
 * session group.
 *
 * The argument on_exit is set to 1 if called when a process is
 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
 */
voiddisassociate_ctty(int on_exit)
{
struct tty_struct *tty = current->tty;
struct task_struct *p;
int tty_pgrp = -1;

if(tty) {
 tty_pgrp = tty->pgrp;
if(on_exit && tty->driver.type != TTY_DRIVER_TYPE_PTY)
tty_vhangup(tty);
}else{
if(current->tty_old_pgrp) {
kill_pg(current->tty_old_pgrp, SIGHUP, on_exit);
kill_pg(current->tty_old_pgrp, SIGCONT, on_exit);
}
return;
}
if(tty_pgrp >0) {
kill_pg(tty_pgrp, SIGHUP, on_exit);
if(!on_exit)
kill_pg(tty_pgrp, SIGCONT, on_exit);
}

 current->tty_old_pgrp =0;
 tty->session =0;
 tty->pgrp = -1;

for_each_task(p)
if(p->session == current->session)
 p->tty = NULL;
}

/*
 * Sometimes we want to wait until a particular VT has been activated. We
 * do it in a very simple manner. Everybody waits on a single queue and
 * get woken up at once. Those that are satisfied go on with their business,
 * while those not ready go back to sleep. Seems overkill to add a wait
 * to each vt just for this - usually this does nothing!
 */
static struct wait_queue *vt_activate_queue = NULL;

/*
 * Sleeps until a vt is activated, or the task is interrupted. Returns
 * 0 if activation, -1 if interrupted.
 */
intvt_waitactive(void)
{
interruptible_sleep_on(&vt_activate_queue);
return(current->signal & ~current->blocked) ? -1:0;
}

#define vt_wake_waitactive() wake_up(&vt_activate_queue)

voidreset_vc(unsigned int new_console)
{
 vt_cons[new_console]->vc_mode = KD_TEXT;
 kbd_table[new_console].kbdmode = VC_XLATE;
 vt_cons[new_console]->vt_mode.mode = VT_AUTO;
 vt_cons[new_console]->vt_mode.waitv =0;
 vt_cons[new_console]->vt_mode.relsig =0;
 vt_cons[new_console]->vt_mode.acqsig =0;
 vt_cons[new_console]->vt_mode.frsig =0;
 vt_cons[new_console]->vt_pid = -1;
 vt_cons[new_console]->vt_newvt = -1;
reset_palette(new_console) ;
}

/*
 * Performs the back end of a vt switch
 */
voidcomplete_change_console(unsigned int new_console)
{
unsigned char old_vc_mode;

if((new_console == fg_console) || (vt_dont_switch))
return;
if(!vc_cons_allocated(new_console))
return;
 last_console = fg_console;

/*
 * If we're switching, we could be going from KD_GRAPHICS to
 * KD_TEXT mode or vice versa, which means we need to blank or
 * unblank the screen later.
 */
 old_vc_mode = vt_cons[fg_console]->vc_mode;
update_screen(new_console);

/*
 * If this new console is under process control, send it a signal
 * telling it that it has acquired. Also check if it has died and
 * clean up (similar to logic employed in change_console())
 */
if(vt_cons[new_console]->vt_mode.mode == VT_PROCESS)
{
/*
 * Send the signal as privileged - kill_proc() will
 * tell us if the process has gone or something else
 * is awry
 */
if(kill_proc(vt_cons[new_console]->vt_pid,
 vt_cons[new_console]->vt_mode.acqsig,
1) !=0)
{
/*
 * The controlling process has died, so we revert back to
 * normal operation. In this case, we'll also change back
 * to KD_TEXT mode. I'm not sure if this is strictly correct
 * but it saves the agony when the X server dies and the screen
 * remains blanked due to KD_GRAPHICS! It would be nice to do
 * this outside of VT_PROCESS but there is no single process
 * to account for and tracking tty count may be undesirable.
 */
reset_vc(new_console);
}
}

/*
 * We do this here because the controlling process above may have
 * gone, and so there is now a new vc_mode
 */
if(old_vc_mode != vt_cons[new_console]->vc_mode)
{
if(vt_cons[new_console]->vc_mode == KD_TEXT)
do_unblank_screen();
else
do_blank_screen(1);
}

/* Set the colour palette for this VT */
if(vt_cons[new_console]->vc_mode == KD_TEXT)
set_palette() ;

/*
 * Wake anyone waiting for their VT to activate
 */
vt_wake_waitactive();
return;
}

/*
 * Performs the front-end of a vt switch
 */
voidchange_console(unsigned int new_console)
{
if((new_console == fg_console) || (vt_dont_switch))
return;
if(!vc_cons_allocated(new_console))
return;

/*
 * If this vt is in process mode, then we need to handshake with
 * that process before switching. Essentially, we store where that
 * vt wants to switch to and wait for it to tell us when it's done
 * (via VT_RELDISP ioctl).
 *
 * We also check to see if the controlling process still exists.
 * If it doesn't, we reset this vt to auto mode and continue.
 * This is a cheap way to track process control. The worst thing
 * that can happen is: we send a signal to a process, it dies, and
 * the switch gets "lost" waiting for a response; hopefully, the
 * user will try again, we'll detect the process is gone (unless
 * the user waits just the right amount of time :-) and revert the
 * vt to auto control.
 */
if(vt_cons[fg_console]->vt_mode.mode == VT_PROCESS)
{
/*
 * Send the signal as privileged - kill_proc() will
 * tell us if the process has gone or something else
 * is awry
 */
if(kill_proc(vt_cons[fg_console]->vt_pid,
 vt_cons[fg_console]->vt_mode.relsig,
1) ==0)
{
/*
 * It worked. Mark the vt to switch to and
 * return. The process needs to send us a
 * VT_RELDISP ioctl to complete the switch.
 */
 vt_cons[fg_console]->vt_newvt = new_console;
return;
}

/*
 * The controlling process has died, so we revert back to
 * normal operation. In this case, we'll also change back
 * to KD_TEXT mode. I'm not sure if this is strictly correct
 * but it saves the agony when the X server dies and the screen
 * remains blanked due to KD_GRAPHICS! It would be nice to do
 * this outside of VT_PROCESS but there is no single process
 * to account for and tracking tty count may be undesirable.
 */
reset_vc(fg_console);

/*
 * Fall through to normal (VT_AUTO) handling of the switch...
 */
}

/*
 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
 */
if(vt_cons[fg_console]->vc_mode == KD_GRAPHICS)
return;

complete_change_console(new_console);
}

voidwait_for_keypress(void)
{
sleep_on(&keypress_wait);
}

voidstop_tty(struct tty_struct *tty)
{
if(tty->stopped)
return;
 tty->stopped =1;
if(tty->link && tty->link->packet) {
 tty->ctrl_status &= ~TIOCPKT_START;
 tty->ctrl_status |= TIOCPKT_STOP;
wake_up_interruptible(&tty->link->read_wait);
}
if(tty->driver.stop)
(tty->driver.stop)(tty);
}

voidstart_tty(struct tty_struct *tty)
{
if(!tty->stopped || tty->flow_stopped)
return;
 tty->stopped =0;
if(tty->link && tty->link->packet) {
 tty->ctrl_status &= ~TIOCPKT_STOP;
 tty->ctrl_status |= TIOCPKT_START;
wake_up_interruptible(&tty->link->read_wait);
}
if(tty->driver.start)
(tty->driver.start)(tty);
if((tty->flags & (1<< TTY_DO_WRITE_WAKEUP)) &&
 tty->ldisc.write_wakeup)
(tty->ldisc.write_wakeup)(tty);
wake_up_interruptible(&tty->write_wait);
}

static longtty_read(struct inode * inode,struct file * file,
char* buf,unsigned long count)
{
int i;
struct tty_struct * tty;

 tty = (struct tty_struct *)file->private_data;
if(tty_paranoia_check(tty, inode->i_rdev,"tty_read"))
return-EIO;
if(!tty || (tty->flags & (1<< TTY_IO_ERROR)))
return-EIO;

/* This check not only needs to be done before reading, but also
 whenever read_chan() gets woken up after sleeping, so I've
 moved it to there. This should only be done for the N_TTY
 line discipline, anyway. Same goes for write_chan(). -- jlc. */
#if 0
if((inode->i_rdev != CONSOLE_DEV) &&/* don't stop on /dev/console */
(tty->pgrp >0) &&
(current->tty == tty) &&
(tty->pgrp != current->pgrp))
if(is_ignored(SIGTTIN) ||is_orphaned_pgrp(current->pgrp))
return-EIO;
else{
(void)kill_pg(current->pgrp, SIGTTIN,1);
return-ERESTARTSYS;
}
#endif
if(tty->ldisc.read)
 i = (tty->ldisc.read)(tty,file,buf,count);
else
 i = -EIO;
if(i >0)
 inode->i_atime = CURRENT_TIME;
return i;
}

/*
 * Split writes up in sane blocksizes to avoid
 * denial-of-service type attacks
 */
staticinlineintdo_tty_write(
int(*write)(struct tty_struct *,struct file *,const unsigned char*,unsigned int),
struct inode *inode,
struct tty_struct *tty,
struct file *file,
const unsigned char*buf,
unsigned int count)
{
int ret =0, written =0;

for(;;) {
unsigned long size = PAGE_SIZE*2;
if(size > count)
 size = count;
 ret =write(tty, file, buf, size);
if(ret <=0)
break;
 written += ret;
 buf += ret;
 count -= ret;
if(!count)
break;
 ret = -ERESTARTSYS;
if(current->signal & ~current->blocked)
break;
if(need_resched)
schedule();
}
if(written) {
 inode->i_mtime = CURRENT_TIME;
 ret = written;
}
return ret;
}


static longtty_write(struct inode * inode,struct file * file,
const char* buf,unsigned long count)
{
int is_console;
struct tty_struct * tty;

 is_console = (inode->i_rdev == CONSOLE_DEV);

if(is_console && redirect)
 tty = redirect;
else
 tty = (struct tty_struct *)file->private_data;
if(tty_paranoia_check(tty, inode->i_rdev,"tty_write"))
return-EIO;
if(!tty || !tty->driver.write || (tty->flags & (1<< TTY_IO_ERROR)))
return-EIO;
#if 0
if(!is_console &&L_TOSTOP(tty) && (tty->pgrp >0) &&
(current->tty == tty) && (tty->pgrp != current->pgrp)) {
if(is_orphaned_pgrp(current->pgrp))
return-EIO;
if(!is_ignored(SIGTTOU)) {
(void)kill_pg(current->pgrp, SIGTTOU,1);
return-ERESTARTSYS;
}
}
#endif
if(!tty->ldisc.write)
return-EIO;
returndo_tty_write(tty->ldisc.write,
 inode, tty, file,
(const unsigned char*)buf,
(unsigned int)count);
}

/*
 * This is so ripe with races that you should *really* not touch this
 * unless you know exactly what you are doing. All the changes have to be
 * made atomically, or there may be incorrect pointers all over the place.
 */
static intinit_dev(kdev_t device,struct tty_struct **ret_tty)
{
struct tty_struct *tty, **tty_loc, *o_tty, **o_tty_loc;
struct termios *tp, **tp_loc, *o_tp, **o_tp_loc;
struct termios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
struct tty_driver *driver;
int retval;
int idx;

 driver =get_tty_driver(device);
if(!driver)
return-ENODEV;

 idx =MINOR(device) - driver->minor_start;
 tty = o_tty = NULL;
 tp = o_tp = NULL;
 ltp = o_ltp = NULL;
 o_tty_loc = NULL;
 o_tp_loc = o_ltp_loc = NULL;

 tty_loc = &driver->table[idx];
 tp_loc = &driver->termios[idx];
 ltp_loc = &driver->termios_locked[idx];

repeat:
 retval = -EIO;
if(driver->type == TTY_DRIVER_TYPE_PTY &&
 driver->subtype == PTY_TYPE_MASTER &&
*tty_loc && (*tty_loc)->count)
goto end_init;
 retval = -ENOMEM;
if(!*tty_loc && !tty) {
if(!(tty = (struct tty_struct*)get_free_page(GFP_KERNEL)))
goto end_init;
initialize_tty_struct(tty);
 tty->device = device;
 tty->driver = *driver;
goto repeat;
}
if(!*tp_loc && !tp) {
 tp = (struct termios *)kmalloc(sizeof(struct termios),
 GFP_KERNEL);
if(!tp)
goto end_init;
*tp = driver->init_termios;
goto repeat;
}
if(!*ltp_loc && !ltp) {
 ltp = (struct termios *)kmalloc(sizeof(struct termios),
 GFP_KERNEL);
if(!ltp)
goto end_init;
memset(ltp,0,sizeof(struct termios));
goto repeat;
}
if(driver->type == TTY_DRIVER_TYPE_PTY) {
 o_tty_loc = &driver->other->table[idx];
 o_tp_loc = &driver->other->termios[idx];
 o_ltp_loc = &driver->other->termios_locked[idx];

if(!*o_tty_loc && !o_tty) {
 kdev_t o_device;

 o_tty = (struct tty_struct *)
get_free_page(GFP_KERNEL);
if(!o_tty)
goto end_init;
 o_device =MKDEV(driver->other->major,
 driver->other->minor_start + idx);
initialize_tty_struct(o_tty);
 o_tty->device = o_device;
 o_tty->driver = *driver->other;
goto repeat;
}
if(!*o_tp_loc && !o_tp) {
 o_tp = (struct termios *)
kmalloc(sizeof(struct termios), GFP_KERNEL);
if(!o_tp)
goto end_init;
*o_tp = driver->other->init_termios;
goto repeat;
}
if(!*o_ltp_loc && !o_ltp) {
 o_ltp = (struct termios *)
kmalloc(sizeof(struct termios), GFP_KERNEL);
if(!o_ltp)
goto end_init;
memset(o_ltp,0,sizeof(struct termios));
goto repeat;
}

}
/* Now we have allocated all the structures: update all the pointers.. */
if(!*tp_loc) {
*tp_loc = tp;
 tp = NULL;
}
if(!*ltp_loc) {
*ltp_loc = ltp;
 ltp = NULL;
}
if(!*tty_loc) {
 tty->termios = *tp_loc;
 tty->termios_locked = *ltp_loc;
*tty_loc = tty;
(*driver->refcount)++;
(*tty_loc)->count++;
if(tty->ldisc.open) {
 retval = (tty->ldisc.open)(tty);
if(retval <0) {
(*tty_loc)->count--;
 tty = NULL;
goto end_init;
}
}
 tty = NULL;
}else{
if((*tty_loc)->flags & (1<< TTY_CLOSING)) {
printk("Attempt to open closing tty %s.\n",
tty_name(*tty_loc));
printk("Ack!!!! This should never happen!!\n");
return-EINVAL;
}
(*tty_loc)->count++;
}
if(driver->type == TTY_DRIVER_TYPE_PTY) {
if(!*o_tp_loc) {
*o_tp_loc = o_tp;
 o_tp = NULL;
}
if(!*o_ltp_loc) {
*o_ltp_loc = o_ltp;
 o_ltp = NULL;
}
if(!*o_tty_loc) {
 o_tty->termios = *o_tp_loc;
 o_tty->termios_locked = *o_ltp_loc;
*o_tty_loc = o_tty;
(*driver->other->refcount)++;
if(o_tty->ldisc.open) {
 retval = (o_tty->ldisc.open)(o_tty);
if(retval <0) {
(*tty_loc)->count--;
 o_tty = NULL;
goto end_init;
}
}
 o_tty = NULL;
}
(*tty_loc)->link = *o_tty_loc;
(*o_tty_loc)->link = *tty_loc;
if(driver->subtype == PTY_TYPE_MASTER)
(*o_tty_loc)->count++;
}
(*tty_loc)->driver = *driver;
*ret_tty = *tty_loc;
 retval =0;
end_init:
if(tty)
free_page((unsigned long) tty);
if(o_tty)
free_page((unsigned long) o_tty);
if(tp)
kfree_s(tp,sizeof(struct termios));
if(o_tp)
kfree_s(o_tp,sizeof(struct termios));
if(ltp)
kfree_s(ltp,sizeof(struct termios));
if(o_ltp)
kfree_s(o_ltp,sizeof(struct termios));
return retval;
}

/*
 * Even releasing the tty structures is a tricky business.. We have
 * to be very careful that the structures are all released at the
 * same time, as interrupts might otherwise get the wrong pointers.
 */
static voidrelease_dev(struct file * filp)
{
struct tty_struct *tty, *o_tty;
struct termios *tp, *o_tp, *ltp, *o_ltp;
struct task_struct **p;
int idx;

 tty = (struct tty_struct *)filp->private_data;
if(tty_paranoia_check(tty, filp->f_inode->i_rdev,"release_dev"))
return;

check_tty_count(tty,"release_dev");

tty_fasync(filp->f_inode, filp,0);

 tp = tty->termios;
 ltp = tty->termios_locked;

 idx =MINOR(tty->device) - tty->driver.minor_start;
#ifdef TTY_PARANOIA_CHECK
if(idx <0|| idx >= tty->driver.num) {
printk("release_dev: bad idx when trying to free (%s)\n",
kdevname(tty->device));
return;
}
if(tty != tty->driver.table[idx]) {
printk("release_dev: driver.table[%d] not tty for (%s)\n",
 idx,kdevname(tty->device));
return;
}
if(tp != tty->driver.termios[idx]) {
printk("release_dev: driver.termios[%d] not termios for ("
"%s)\n",
 idx,kdevname(tty->device));
return;
}
if(ltp != tty->driver.termios_locked[idx]) {
printk("release_dev: driver.termios_locked[%d] not termios_locked for ("
"%s)\n",
 idx,kdevname(tty->device));
return;
}
#endif

#ifdef TTY_DEBUG_HANGUP
printk("release_dev of %s (tty count=%d)...",tty_name(tty),
 tty->count);
#endif

 o_tty = tty->link;
 o_tp = (o_tty) ? o_tty->termios : NULL;
 o_ltp = (o_tty) ? o_tty->termios_locked : NULL;

#ifdef TTY_PARANOIA_CHECK
if(tty->driver.other) {
if(o_tty != tty->driver.other->table[idx]) {
printk("release_dev: other->table[%d] not o_tty for ("
"%s)\n",
 idx,kdevname(tty->device));
return;
}
if(o_tp != tty->driver.other->termios[idx]) {
printk("release_dev: other->termios[%d] not o_termios for ("
"%s)\n",
 idx,kdevname(tty->device));
return;
}
if(o_ltp != tty->driver.other->termios_locked[idx]) {
printk("release_dev: other->termios_locked[%d] not o_termios_locked for ("
"%s)\n",
 idx,kdevname(tty->device));
return;
}

if(o_tty->link != tty) {
printk("release_dev: bad pty pointers\n");
return;
}
}
#endif

if(tty->driver.close)
 tty->driver.close(tty, filp);
if(tty->driver.type == TTY_DRIVER_TYPE_PTY &&
 tty->driver.subtype == PTY_TYPE_MASTER) {
if(--tty->link->count <0) {
printk("release_dev: bad pty slave count (%d) for %s\n",
 tty->count,tty_name(tty));
 tty->link->count =0;
}
}
if(--tty->count <0) {
printk("release_dev: bad tty->count (%d) for %s\n",
 tty->count,tty_name(tty));
 tty->count =0;
}
if(tty->count)
return;

/*
 * We're committed; at this point, we must not block!
 */
if(o_tty) {
if(o_tty->count)
return;
 tty->driver.other->table[idx] = NULL;
 tty->driver.other->termios[idx] = NULL;
kfree_s(o_tp,sizeof(struct termios));
}

#ifdef TTY_DEBUG_HANGUP
printk("freeing tty structure...");
#endif
 tty->flags |= (1<< TTY_CLOSING);

/*
 * Make sure there aren't any processes that still think this
 * tty is their controlling tty.
 */
for(p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
if(*p ==0)
continue;
if((*p)->tty == tty)
(*p)->tty = NULL;
if(o_tty && (*p)->tty == o_tty)
(*p)->tty = NULL;
}

/*
 * Shutdown the current line discipline, and reset it to
 * N_TTY.
 */
if(tty->ldisc.close)
(tty->ldisc.close)(tty);
 tty->ldisc = ldiscs[N_TTY];
 tty->termios->c_line = N_TTY;
if(o_tty) {
if(o_tty->ldisc.close)
(o_tty->ldisc.close)(o_tty);
 o_tty->ldisc = ldiscs[N_TTY];
}

 tty->driver.table[idx] = NULL;
if(tty->driver.flags & TTY_DRIVER_RESET_TERMIOS) {
 tty->driver.termios[idx] = NULL;
kfree_s(tp,sizeof(struct termios));
}
if(tty == redirect || o_tty == redirect)
 redirect = NULL;
/*
 * Make sure that the tty's task queue isn't activated. If it
 * is, take it out of the linked list.
 */
cli();
if(tty->flip.tqueue.sync) {
struct tq_struct *tq, *prev;

for(tq=tq_timer, prev=0; tq; prev=tq, tq=tq->next) {
if(tq == &tty->flip.tqueue) {
if(prev)
 prev->next = tq->next;
else
 tq_timer = tq->next;
break;
}
}
}
sti();
 tty->magic =0;
(*tty->driver.refcount)--;
free_page((unsigned long) tty);
 filp->private_data =0;
if(o_tty) {
 o_tty->magic =0;
(*o_tty->driver.refcount)--;
free_page((unsigned long) o_tty);
}
}

/*
 * tty_open and tty_release keep up the tty count that contains the
 * number of opens done on a tty. We cannot use the inode-count, as
 * different inodes might point to the same tty.
 *
 * Open-counting is needed for pty masters, as well as for keeping
 * track of serial lines: DTR is dropped when the last close happens.
 * (This is not done solely through tty->count, now. - Ted 1/27/92)
 *
 * The termios state of a pty is reset on first open so that
 * settings don't persist across reuse.
 */
static inttty_open(struct inode * inode,struct file * filp)
{
struct tty_struct *tty;
int minor;
int noctty, retval;
 kdev_t device;

retry_open:
 noctty = filp->f_flags & O_NOCTTY;
 device = inode->i_rdev;
if(device == TTY_DEV) {
if(!current->tty)
return-ENXIO;
 device = current->tty->device;
/* noctty = 1; */
}
if(device == CONSOLE_DEV) {
 device =MKDEV(TTY_MAJOR, fg_console+1);
 noctty =1;
}
 minor =MINOR(device);

 retval =init_dev(device, &tty);
if(retval)
return retval;
 filp->private_data = tty;
check_tty_count(tty,"tty_open");
if(tty->driver.type == TTY_DRIVER_TYPE_PTY &&
 tty->driver.subtype == PTY_TYPE_MASTER)
 noctty =1;
#ifdef TTY_DEBUG_HANGUP
printk("opening %s...",tty_name(tty));
#endif
if(tty->driver.open)
 retval = tty->driver.open(tty, filp);
else
 retval = -ENODEV;

if(!retval &&test_bit(TTY_EXCLUSIVE, &tty->flags) && !suser())
 retval = -EBUSY;

if(retval) {
#ifdef TTY_DEBUG_HANGUP
printk("error %d in opening %s...", retval,tty_name(tty));
#endif

release_dev(filp);
if(retval != -ERESTARTSYS)
return retval;
if(current->signal & ~current->blocked)
return retval;
schedule();
/*
 * Need to reset f_op in case a hangup happened.
 */
 filp->f_op = &tty_fops;
goto retry_open;
}
if(!noctty &&
 current->leader &&
!current->tty &&
 tty->session ==0) {
 current->tty = tty;
 current->tty_old_pgrp =0;
 tty->session = current->session;
 tty->pgrp = current->pgrp;
}
return0;
}

/*
 * Note that releasing a pty master also releases the child, so
 * we have to make the redirection checks after that and on both
 * sides of a pty.
 */
static voidtty_release(struct inode * inode,struct file * filp)
{
release_dev(filp);
}

static inttty_select(struct inode * inode,struct file * filp,int sel_type, select_table * wait)
{
struct tty_struct * tty;

 tty = (struct tty_struct *)filp->private_data;
if(tty_paranoia_check(tty, inode->i_rdev,"tty_select"))
return0;

if(tty->ldisc.select)
return(tty->ldisc.select)(tty, inode, filp, sel_type, wait);
return0;
}

/*
 * fasync_helper() is used by some character device drivers (mainly mice)
 * to set up the fasync queue. It returns negative on error, 0 if it did
 * no changes and positive if it added/deleted the entry.
 */
intfasync_helper(struct inode * inode,struct file * filp,int on,struct fasync_struct **fapp)
{
struct fasync_struct *fa, **fp;
unsigned long flags;

for(fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
if(fa->fa_file == filp)
break;
}

if(on) {
if(fa)
return0;
 fa = (struct fasync_struct *)kmalloc(sizeof(struct fasync_struct), GFP_KERNEL);
if(!fa)
return-ENOMEM;
 fa->magic = FASYNC_MAGIC;
 fa->fa_file = filp;
save_flags(flags);
cli();
 fa->fa_next = *fapp;
*fapp = fa;
restore_flags(flags);
return1;
}
if(!fa)
return0;
save_flags(flags);
cli();
*fp = fa->fa_next;
restore_flags(flags);
kfree(fa);
return1;
}

static inttty_fasync(struct inode * inode,struct file * filp,int on)
{
struct tty_struct * tty;
int retval;

 tty = (struct tty_struct *)filp->private_data;
if(tty_paranoia_check(tty, inode->i_rdev,"tty_fasync"))
return0;

 retval =fasync_helper(inode, filp, on, &tty->fasync);
if(retval <=0)
return retval;

if(on) {
if(!waitqueue_active(&tty->read_wait))
 tty->minimum_to_wake =1;
if(filp->f_owner ==0) {
if(tty->pgrp)
 filp->f_owner = -tty->pgrp;
else
 filp->f_owner = current->pid;
}
}else{
if(!tty->fasync && !waitqueue_active(&tty->read_wait))
 tty->minimum_to_wake = N_TTY_BUF_SIZE;
}
return0;
}

#if 0
/*
 * XXX does anyone use this anymore?!?
 */
static intdo_get_ps_info(unsigned long arg)
{
struct tstruct {
int flag;
int present[NR_TASKS];
struct task_struct tasks[NR_TASKS];
};
struct tstruct *ts = (struct tstruct *)arg;
struct task_struct **p;
char*c, *d;
int i, n =0;

 i =verify_area(VERIFY_WRITE, (void*)arg,sizeof(struct tstruct));
if(i)
return i;
for(p = &FIRST_TASK ; p <= &LAST_TASK ; p++, n++)
if(*p)
{
 c = (char*)(*p);
 d = (char*)(ts->tasks+n);
for(i=0; i<sizeof(struct task_struct) ; i++)
put_user(*c++, d++);
put_user(1, ts->present+n);
}
else
put_user(0, ts->present+n);
return(0);
}
#endif

static inttiocsti(struct tty_struct *tty,char* arg)
{
char ch, mbz =0;

if((current->tty != tty) && !suser())
return-EPERM;
if(get_user(ch, arg))
return-EFAULT;
 tty->ldisc.receive_buf(tty, &ch, &mbz,1);
return0;
}

static inttiocgwinsz(struct tty_struct *tty,struct winsize * arg)
{
if(copy_to_user(arg, &tty->winsize,sizeof(*arg)))
return-EFAULT;
return0;
}

static inttiocswinsz(struct tty_struct *tty,struct tty_struct *real_tty,
struct winsize * arg)
{
struct winsize tmp_ws;

if(copy_from_user(&tmp_ws, arg,sizeof(*arg)))
return-EFAULT;
if(!memcmp(&tmp_ws, &tty->winsize,sizeof(*arg)))
return0;
if(tty->pgrp >0)
kill_pg(tty->pgrp, SIGWINCH,1);
if((real_tty->pgrp != tty->pgrp) && (real_tty->pgrp >0))
kill_pg(real_tty->pgrp, SIGWINCH,1);
 tty->winsize = tmp_ws;
 real_tty->winsize = tmp_ws;
return0;
}

static inttioccons(struct tty_struct *tty,struct tty_struct *real_tty)
{
if(tty->driver.type == TTY_DRIVER_TYPE_CONSOLE) {
if(!suser())
return-EPERM;
 redirect = NULL;
return0;
}
if(redirect)
return-EBUSY;
 redirect = real_tty;
return0;
}


static intfionbio(struct file *file,int*arg)
{
int nonblock;

if(get_user(nonblock, arg))
return-EFAULT;

if(nonblock)
 file->f_flags |= O_NONBLOCK;
else
 file->f_flags &= ~O_NONBLOCK;
return0;
}

static inttiocsctty(struct tty_struct *tty,int arg)
{
if(current->leader &&
(current->session == tty->session))
return0;
/*
 * The process must be a session leader and
 * not have a controlling tty already.
 */
if(!current->leader || current->tty)
return-EPERM;
if(tty->session >0) {
/*
 * This tty is already the controlling
 * tty for another session group!
 */
if((arg ==1) &&suser()) {
/*
 * Steal it away
 */
struct task_struct *p;

for_each_task(p)
if(p->tty == tty)
 p->tty = NULL;
}else
return-EPERM;
}
 current->tty = tty;
 current->tty_old_pgrp =0;
 tty->session = current->session;
 tty->pgrp = current->pgrp;
return0;
}

static inttiocgpgrp(struct tty_struct *tty,struct tty_struct *real_tty, pid_t *arg)
{
/*
 * (tty == real_tty) is a cheap way of
 * testing if the tty is NOT a master pty.
 */
if(tty == real_tty && current->tty != real_tty)
return-ENOTTY;
returnput_user(real_tty->pgrp, arg);
}

static inttiocspgrp(struct tty_struct *tty,struct tty_struct *real_tty, pid_t *arg)
{
 pid_t pgrp;
int retval =tty_check_change(real_tty);

if(retval == -EIO)
return-ENOTTY;
if(retval)
return retval;
if(!current->tty ||
(current->tty != real_tty) ||
(real_tty->session != current->session))
return-ENOTTY;
get_user(pgrp, (pid_t *) arg);
if(pgrp <0)
return-EINVAL;
if(session_of_pgrp(pgrp) != current->session)
return-EPERM;
 real_tty->pgrp = pgrp;
return0;
}

static inttioclinux(struct tty_struct *tty,unsigned long arg)
{
char type, data;

if(tty->driver.type != TTY_DRIVER_TYPE_CONSOLE)
return-EINVAL;
if(current->tty != tty && !suser())
return-EPERM;
if(get_user(type, (char*)arg))
return-EFAULT;
switch(type)
{
case2:
returnset_selection(arg, tty,1);
case3:
returnpaste_selection(tty);
case4:
do_unblank_screen();
return0;
case5:
returnsel_loadlut(arg);
case6:

/*
 * Make it possible to react to Shift+Mousebutton.
 * Note that 'shift_state' is an undocumented
 * kernel-internal variable; programs not closely
 * related to the kernel should not use this.
 */
 data = shift_state;
returnput_user(data, (char*) arg);
case7:
 data =mouse_reporting();
returnput_user(data, (char*) arg);
case10:
set_vesa_blanking(arg);
return0;
case11:/* set kmsg redirect */
if(!suser())
return-EPERM;
if(get_user(data, (char*)arg+1))
return-EFAULT;
 kmsg_redirect = data;
return0;
case12:/* get fg_console */
return fg_console;
}
return-EINVAL;
}

static inttiocttygstruct(struct tty_struct *tty,struct tty_struct *arg)
{
if(copy_to_user(arg, tty,sizeof(*arg)))
return-EFAULT;
return0;
}

static inttiocsetd(struct tty_struct *tty,int*arg)
{
int retval, ldisc;

 retval =tty_check_change(tty);
if(retval)
return retval;
 retval =get_user(ldisc, arg);
if(retval)
return retval;
returntty_set_ldisc(tty, ldisc);
}

/*
 * Split this up, as gcc can choke on it otherwise..
 */
static inttty_ioctl(struct inode * inode,struct file * file,
unsigned int cmd,unsigned long arg)
{
struct tty_struct *tty, *real_tty;

 tty = (struct tty_struct *)file->private_data;
if(tty_paranoia_check(tty, inode->i_rdev,"tty_ioctl"))
return-EINVAL;

 real_tty = tty;
if(tty->driver.type == TTY_DRIVER_TYPE_PTY &&
 tty->driver.subtype == PTY_TYPE_MASTER)
 real_tty = tty->link;

switch(cmd) {
case TIOCSTI:
returntiocsti(tty, (char*)arg);
case TIOCGWINSZ:
returntiocgwinsz(tty, (struct winsize *) arg);
case TIOCSWINSZ:
returntiocswinsz(tty, real_tty, (struct winsize *) arg);
case TIOCCONS:
returntioccons(tty, real_tty);
case FIONBIO:
returnfionbio(file, (int*) arg);
case TIOCEXCL:
set_bit(TTY_EXCLUSIVE, &tty->flags);
return0;
case TIOCNXCL:
clear_bit(TTY_EXCLUSIVE, &tty->flags);
return0;
case TIOCNOTTY:
if(current->tty != tty)
return-ENOTTY;
if(current->leader)
disassociate_ctty(0);
 current->tty = NULL;
return0;
case TIOCSCTTY:
returntiocsctty(tty, arg);
case TIOCGPGRP:
returntiocgpgrp(tty, real_tty, (pid_t *) arg);
case TIOCSPGRP:
returntiocspgrp(tty, real_tty, (pid_t *) arg);
case TIOCGETD:
returnput_user(tty->ldisc.num, (int*) arg);
case TIOCSETD:
returntiocsetd(tty, (int*) arg);
case TIOCLINUX:
returntioclinux(tty, arg);
case TIOCTTYGSTRUCT:
returntiocttygstruct(tty, (struct tty_struct *) arg);
}
if(tty->driver.ioctl) {
int retval = (tty->driver.ioctl)(tty, file, cmd, arg);
if(retval != -ENOIOCTLCMD)
return retval;
}
if(tty->ldisc.ioctl) {
int retval = (tty->ldisc.ioctl)(tty, file, cmd, arg);
if(retval != -ENOIOCTLCMD)
return retval;
}
return-EINVAL;
}


/*
 * This implements the "Secure Attention Key" --- the idea is to
 * prevent trojan horses by killing all processes associated with this
 * tty when the user hits the "Secure Attention Key". Required for
 * super-paranoid applications --- see the Orange Book for more details.
 * 
 * This code could be nicer; ideally it should send a HUP, wait a few
 * seconds, then send a INT, and then a KILL signal. But you then
 * have to coordinate with the init process, since all processes associated
 * with the current tty must be dead before the new getty is allowed
 * to spawn.
 */
voiddo_SAK(struct tty_struct *tty)
{
#ifdef TTY_SOFT_SAK
tty_hangup(tty);
#else
struct task_struct **p;
int session;
int i;
struct file *filp;

if(!tty)
return;
 session = tty->session;
if(tty->ldisc.flush_buffer)
 tty->ldisc.flush_buffer(tty);
if(tty->driver.flush_buffer)
 tty->driver.flush_buffer(tty);
for(p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
if(!(*p))
continue;
if(((*p)->tty == tty) ||
((session >0) && ((*p)->session == session)))
send_sig(SIGKILL, *p,1);
else if((*p)->files) {
for(i=0; i < NR_OPEN; i++) {
 filp = (*p)->files->fd[i];
if(filp && (filp->f_op == &tty_fops) &&
(filp->private_data == tty)) {
send_sig(SIGKILL, *p,1);
break;
}
}
}
}
#endif
}

/*
 * This routine is called out of the software interrupt to flush data
 * from the flip buffer to the line discipline.
 */
static voidflush_to_ldisc(void*private_)
{
struct tty_struct *tty = (struct tty_struct *) private_;
unsigned char*cp;
char*fp;
int count;

if(tty->flip.buf_num) {
 cp = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
 fp = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
 tty->flip.buf_num =0;

cli();
 tty->flip.char_buf_ptr = tty->flip.char_buf;
 tty->flip.flag_buf_ptr = tty->flip.flag_buf;
}else{
 cp = tty->flip.char_buf;
 fp = tty->flip.flag_buf;
 tty->flip.buf_num =1;

cli();
 tty->flip.char_buf_ptr = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
 tty->flip.flag_buf_ptr = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
}
 count = tty->flip.count;
 tty->flip.count =0;
sti();

#if 0
if(count > tty->max_flip_cnt)
 tty->max_flip_cnt = count;
#endif
 tty->ldisc.receive_buf(tty, cp, fp, count);
}

/*
 * This subroutine initializes a tty structure.
 */
static voidinitialize_tty_struct(struct tty_struct *tty)
{
memset(tty,0,sizeof(struct tty_struct));
 tty->magic = TTY_MAGIC;
 tty->ldisc = ldiscs[N_TTY];
 tty->pgrp = -1;
 tty->flip.char_buf_ptr = tty->flip.char_buf;
 tty->flip.flag_buf_ptr = tty->flip.flag_buf;
 tty->flip.tqueue.routine = flush_to_ldisc;
 tty->flip.tqueue.data = tty;
}

/*
 * The default put_char routine if the driver did not define one.
 */
voidtty_default_put_char(struct tty_struct *tty,unsigned char ch)
{
 tty->driver.write(tty,0, &ch,1);
}

/*
 * Called by a tty driver to register itself.
 */
inttty_register_driver(struct tty_driver *driver)
{
int error;

if(driver->flags & TTY_DRIVER_INSTALLED)
return0;

 error =register_chrdev(driver->major, driver->name, &tty_fops);
if(error <0)
return error;
else if(driver->major ==0)
 driver->major = error;

if(!driver->put_char)
 driver->put_char = tty_default_put_char;

 driver->prev =0;
 driver->next = tty_drivers;
if(tty_drivers) tty_drivers->prev = driver;
 tty_drivers = driver;
return error;
}

/*
 * Called by a tty driver to unregister itself.
 */
inttty_unregister_driver(struct tty_driver *driver)
{
int retval;
struct tty_driver *p;
int found =0;
const char*othername = NULL;

if(*driver->refcount)
return-EBUSY;

for(p = tty_drivers; p; p = p->next) {
if(p == driver)
 found++;
else if(p->major == driver->major)
 othername = p->name;
}

if(!found)
return-ENOENT;

if(othername == NULL) {
 retval =unregister_chrdev(driver->major, driver->name);
if(retval)
return retval;
}else
register_chrdev(driver->major, othername, &tty_fops);

if(driver->prev)
 driver->prev->next = driver->next;
else
 tty_drivers = driver->next;

if(driver->next)
 driver->next->prev = driver->prev;

return0;
}


/*
 * Initialize the console device. This is called *early*, so
 * we can't necessarily depend on lots of kernel help here.
 * Just do some early initializations, and do the complex setup
 * later.
 */
longconsole_init(long kmem_start,long kmem_end)
{
/* Setup the default TTY line discipline. */
memset(ldiscs,0,sizeof(ldiscs));
(void)tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY);

/*
 * Set up the standard termios. Individual tty drivers may 
 * deviate from this; this is used as a template.
 */
memset(&tty_std_termios,0,sizeof(struct termios));
memcpy(tty_std_termios.c_cc, INIT_C_CC, NCCS);
 tty_std_termios.c_iflag = ICRNL | IXON;
 tty_std_termios.c_oflag = OPOST | ONLCR;
 tty_std_termios.c_cflag = B38400 | CS8 | CREAD | HUPCL;
 tty_std_termios.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
 ECHOCTL | ECHOKE | IEXTEN;

/*
 * set up the console device so that later boot sequences can 
 * inform about problems etc..
 */
returncon_init(kmem_start);
}

static struct tty_driver dev_tty_driver, dev_console_driver;

/*
 * Ok, now we can initialize the rest of the tty devices and can count
 * on memory allocations, interrupts etc..
 */
inttty_init(void)
{
if(sizeof(struct tty_struct) > PAGE_SIZE)
panic("size of tty structure > PAGE_SIZE!");

/*
 * dev_tty_driver and dev_console_driver are actually magic
 * devices which get redirected at open time. Nevertheless,
 * we register them so that register_chrdev is called
 * appropriately.
 */
memset(&dev_tty_driver,0,sizeof(struct tty_driver));
 dev_tty_driver.magic = TTY_DRIVER_MAGIC;
 dev_tty_driver.name ="tty";
 dev_tty_driver.name_base =0;
 dev_tty_driver.major = TTY_MAJOR;
 dev_tty_driver.minor_start =0;
 dev_tty_driver.num =1;

if(tty_register_driver(&dev_tty_driver))
panic("Couldn't register /dev/tty driver\n");

 dev_console_driver = dev_tty_driver;
 dev_console_driver.name ="console";
 dev_console_driver.major = TTYAUX_MAJOR;

if(tty_register_driver(&dev_console_driver))
panic("Couldn't register /dev/console driver\n");

kbd_init();
#ifdef CONFIG_ESP/* init ESP before rs, so rs doesn't see the port */
esp_init();
#endif
#ifdef CONFIG_SERIAL
rs_init();
#endif
#ifdef CONFIG_CYCLADES
cy_init();
#endif
#ifdef CONFIG_STALLION
stl_init();
#endif
#ifdef CONFIG_ISTALLION
stli_init();
#endif
#ifdef CONFIG_DIGI
pcxe_init();
#endif
#ifdef CONFIG_RISCOM8
riscom8_init();
#endif
pty_init();
vcs_init();
return0;
}