drivers/char/tty

/* */
This source file includes following definitions.
_tty_name
tty_name
tty_paranoia_check
check_tty_count
tty_register_ldisc
tty_set_ldisc
get_tty_driver
tty_check_change
hung_up_tty_read
hung_up_tty_write
hung_up_tty_select
hung_up_tty_ioctl
tty_lseek
do_tty_hangup
tty_hangup
tty_vhangup
tty_hung_up_p
disassociate_ctty
vt_waitactive
reset_vc
complete_change_console
change_console
wait_for_keypress
stop_tty
start_tty
tty_read
tty_write
init_dev
release_dev
tty_open
tty_release
tty_select
tty_fasync
do_get_ps_info
tty_ioctl
do_SAK
flush_to_ldisc
initialize_tty_struct
tty_default_put_char
tty_register_driver
tty_unregister_driver
console_init
tty_init
   1 /*
   2  *  linux/drivers/char/tty_io.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6 
   7 /*
   8  * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
   9  * or rs-channels. It also implements echoing, cooked mode etc.
  10  *
  11  * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
  12  *
  13  * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
  14  * tty_struct and tty_queue structures.  Previously there was a array
  15  * of 256 tty_struct's which was statically allocated, and the
  16  * tty_queue structures were allocated at boot time.  Both are now
  17  * dynamically allocated only when the tty is open.
  18  *
  19  * Also restructured routines so that there is more of a separation
  20  * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
  21  * the low-level tty routines (serial.c, pty.c, console.c).  This
  22  * makes for cleaner and more compact code.  -TYT, 9/17/92 
  23  *
  24  * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
  25  * which can be dynamically activated and de-activated by the line
  26  * discipline handling modules (like SLIP).
  27  *
  28  * NOTE: pay no attention to the line discipline code (yet); its
  29  * interface is still subject to change in this version...
  30  * -- TYT, 1/31/92
  31  *
  32  * Added functionality to the OPOST tty handling.  No delays, but all
  33  * other bits should be there.
  34  *      -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
  35  *
  36  * Rewrote canonical mode and added more termios flags.
  37  *      -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
  38  */
  39 
  40 #include <linux/types.h>
  41 #include <linux/major.h>
  42 #include <linux/errno.h>
  43 #include <linux/signal.h>
  44 #include <linux/fcntl.h>
  45 #include <linux/sched.h>
  46 #include <linux/interrupt.h>
  47 #include <linux/tty.h>
  48 #include <linux/tty_flip.h>
  49 #include <linux/timer.h>
  50 #include <linux/ctype.h>
  51 #include <linux/kd.h>
  52 #include <linux/mm.h>
  53 #include <linux/string.h>
  54 #include <linux/malloc.h>
  55 #include <linux/config.h>
  56 
  57 #include <asm/segment.h>
  58 #include <asm/system.h>
  59 #include <asm/bitops.h>
  60 
  61 #include "kbd_kern.h"
  62 #include "vt_kern.h"
  63 
  64 #define CONSOLE_DEV MKDEV(TTY_MAJOR,0)
  65 #define TTY_DEV MKDEV(TTYAUX_MAJOR,0)
  66 
  67 #undef TTY_DEBUG_HANGUP
  68 
  69 #define TTY_PARANOIA_CHECK
  70 #define CHECK_TTY_COUNT
  71 
  72 #ifdef CONFIG_SELECTION
  73 extern int set_selection(const int arg, struct tty_struct *tty);
  74 extern int paste_selection(struct tty_struct *tty);
  75 extern int sel_loadlut(const int arg);
  76 extern int mouse_reporting(void);
  77 extern int shift_state;
  78 #endif /* CONFIG_SELECTION */
  79 extern int do_screendump(unsigned long arg, int mode);
  80 extern void do_blank_screen(int nopowersave);
  81 extern void do_unblank_screen(void);
  82 extern void set_vesa_blanking(const unsigned long arg);
  83 
  84 struct termios tty_std_termios;         /* for the benefit of tty drivers  */
  85 struct tty_driver *tty_drivers = NULL;  /* linked list of tty drivers */
  86 struct tty_ldisc ldiscs[NR_LDISCS];     /* line disc dispatch table     */
  87 
  88 /*
  89  * fg_console is the current virtual console,
  90  * last_console is the last used one
  91  * redirect is the pseudo-tty that console output
  92  * is redirected to if asked by TIOCCONS.
  93  */
  94 int fg_console = 0;
  95 int last_console = 0;
  96 struct tty_struct * redirect = NULL;
  97 struct wait_queue * keypress_wait = NULL;
  98 
  99 static void initialize_tty_struct(struct tty_struct *tty);
 100 
 101 static int tty_read(struct inode *, struct file *, char *, int);
 102 static int tty_write(struct inode *, struct file *, char *, int);
 103 static int tty_select(struct inode *, struct file *, int, select_table *);
 104 static int tty_open(struct inode *, struct file *);
 105 static void tty_release(struct inode *, struct file *);
 106 static int tty_ioctl(struct inode * inode, struct file * file,
 107                      unsigned int cmd, unsigned long arg);
 108 static int tty_fasync(struct inode * inode, struct file * filp, int on);
 109 
 110 #ifndef MIN
 111 #define MIN(a,b)        ((a) < (b) ? (a) : (b))
 112 #endif
 113 
 114 /*
 115  * These two routines return the name of tty.  tty_name() should NOT
 116  * be used in interrupt drivers, since it's not re-entrant.  Use
 117  * _tty_name() instead.
 118  */
 119 char *_tty_name(struct tty_struct *tty, char *buf)
     /*  */
 120 {
 121         if (tty)
 122                 sprintf(buf, "%s%d", tty->driver.name,
 123                         MINOR(tty->device) - tty->driver.minor_start +
 124                         tty->driver.name_base);
 125         else
 126                 strcpy(buf, "NULL tty");
 127         return buf;
 128 }
 129 
 130 char *tty_name(struct tty_struct *tty)
     /*  */
 131 {
 132         static char buf[64];
 133 
 134         return(_tty_name(tty, buf));
 135 }
 136 
 137 inline int tty_paranoia_check(struct tty_struct *tty, dev_t device,
     /*  */
 138                               const char *routine)
 139 {
 140 #ifdef TTY_PARANOIA_CHECK
 141         static const char *badmagic =
 142                 "Warning: bad magic number for tty struct (%d, %d) in %s\n";
 143         static const char *badtty =
 144                 "Warning: null TTY for (%d, %d) in %s\n";
 145 
 146         if (!tty) {
 147                 printk(badtty, MAJOR(device), MINOR(device), routine);
 148                 return 1;
 149         }
 150         if (tty->magic != TTY_MAGIC) {
 151                 printk(badmagic, MAJOR(device), MINOR(device), routine);
 152                 return 1;
 153         }
 154 #endif
 155         return 0;
 156 }
 157 
 158 static int check_tty_count(struct tty_struct *tty, const char *routine)
     /*  */
 159 {
 160 #ifdef CHECK_TTY_COUNT
 161         struct file *f;
 162         int i, count = 0;
 163         
 164         for (f = first_file, i=0; i<nr_files; i++, f = f->f_next) {
 165                 if (!f->f_count)
 166                         continue;
 167                 if (f->private_data == tty) {
 168                         count++;
 169                 }
 170         }
 171         if (tty->driver.type == TTY_DRIVER_TYPE_PTY &&
 172             tty->driver.subtype == PTY_TYPE_SLAVE &&
 173             tty->link && tty->link->count)
 174                 count++;
 175         if (tty->count != count) {
 176                 printk("Warning: dev (%d, %d) tty->count(%d) != #fd's(%d) in %s\n",
 177                        MAJOR(tty->device), MINOR(tty->device), tty->count,
 178                        count, routine);
 179                 return count;
 180        }        
 181 #endif
 182         return 0;
 183 }
 184 
 185 int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc)
     /*  */
 186 {
 187         if (disc < N_TTY || disc >= NR_LDISCS)
 188                 return -EINVAL;
 189         
 190         if (new_ldisc) {
 191                 ldiscs[disc] = *new_ldisc;
 192                 ldiscs[disc].flags |= LDISC_FLAG_DEFINED;
 193                 ldiscs[disc].num = disc;
 194         } else
 195                 memset(&ldiscs[disc], 0, sizeof(struct tty_ldisc));
 196         
 197         return 0;
 198 }
 199 
 200 /* Set the discipline of a tty line. */
 201 static int tty_set_ldisc(struct tty_struct *tty, int ldisc)
     /*  */
 202 {
 203         int     retval = 0;
 204         struct  tty_ldisc o_ldisc;
 205 
 206         if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS) ||
 207             !(ldiscs[ldisc].flags & LDISC_FLAG_DEFINED))
 208                 return -EINVAL;
 209 
 210         if (tty->ldisc.num == ldisc)
 211                 return 0;       /* We are already in the desired discipline */
 212         o_ldisc = tty->ldisc;
 213 
 214         /* Shutdown the current discipline. */
 215         if (tty->ldisc.close)
 216                 (tty->ldisc.close)(tty);
 217 
 218         /* Now set up the new line discipline. */
 219         tty->ldisc = ldiscs[ldisc];
 220         tty->termios->c_line = ldisc;
 221         if (tty->ldisc.open)
 222                 retval = (tty->ldisc.open)(tty);
 223         if (retval < 0) {
 224                 tty->ldisc = o_ldisc;
 225                 tty->termios->c_line = tty->ldisc.num;
 226                 if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) {
 227                         tty->ldisc = ldiscs[N_TTY];
 228                         tty->termios->c_line = N_TTY;
 229                         if (tty->ldisc.open) {
 230                                 int r = tty->ldisc.open(tty);
 231 
 232                                 if (r < 0)
 233                                         panic("Couldn't open N_TTY ldisc for "
 234                                               "%s --- error %d.",
 235                                               tty_name(tty), r);
 236                         }
 237                 }
 238         }
 239         if (tty->ldisc.num != o_ldisc.num && tty->driver.set_ldisc)
 240                 tty->driver.set_ldisc(tty);
 241         return retval;
 242 }
 243 
 244 /*
 245  * This routine returns a tty driver structure, given a device number
 246  */
 247 struct tty_driver *get_tty_driver(dev_t device)
     /*  */
 248 {
 249         int     major, minor;
 250         struct tty_driver *p;
 251         
 252         minor = MINOR(device);
 253         major = MAJOR(device);
 254 
 255         for (p = tty_drivers; p; p = p->next) {
 256                 if (p->major != major)
 257                         continue;
 258                 if (minor < p->minor_start)
 259                         continue;
 260                 if (minor >= p->minor_start + p->num)
 261                         continue;
 262                 return p;
 263         }
 264         return NULL;
 265 }
 266 
 267 /*
 268  * If we try to write to, or set the state of, a terminal and we're
 269  * not in the foreground, send a SIGTTOU.  If the signal is blocked or
 270  * ignored, go ahead and perform the operation.  (POSIX 7.2)
 271  */
 272 int tty_check_change(struct tty_struct * tty)
     /*  */
 273 {
 274         if (current->tty != tty)
 275                 return 0;
 276         if (tty->pgrp <= 0) {
 277                 printk("tty_check_change: tty->pgrp <= 0!\n");
 278                 return 0;
 279         }
 280         if (current->pgrp == tty->pgrp)
 281                 return 0;
 282         if (is_ignored(SIGTTOU))
 283                 return 0;
 284         if (is_orphaned_pgrp(current->pgrp))
 285                 return -EIO;
 286         (void) kill_pg(current->pgrp,SIGTTOU,1);
 287         return -ERESTARTSYS;
 288 }
 289 
 290 static int hung_up_tty_read(struct inode * inode, struct file * file, char * buf, int count)
     /*  */
 291 {
 292         return 0;
 293 }
 294 
 295 static int hung_up_tty_write(struct inode * inode, struct file * file, char * buf, int count)
     /*  */
 296 {
 297         return -EIO;
 298 }
 299 
 300 static int hung_up_tty_select(struct inode * inode, struct file * filp, int sel_type, select_table * wait)
     /*  */
 301 {
 302         return 1;
 303 }
 304 
 305 static int hung_up_tty_ioctl(struct inode * inode, struct file * file,
     /*  */
 306                              unsigned int cmd, unsigned long arg)
 307 {
 308         return -EIO;
 309 }
 310 
 311 static int tty_lseek(struct inode * inode, struct file * file, off_t offset, int orig)
     /*  */
 312 {
 313         return -ESPIPE;
 314 }
 315 
 316 static struct file_operations tty_fops = {
 317         tty_lseek,
 318         tty_read,
 319         tty_write,
 320         NULL,           /* tty_readdir */
 321         tty_select,
 322         tty_ioctl,
 323         NULL,           /* tty_mmap */
 324         tty_open,
 325         tty_release,
 326         NULL,           /* tty_fsync */
 327         tty_fasync
 328 };
 329 
 330 static struct file_operations hung_up_tty_fops = {
 331         tty_lseek,
 332         hung_up_tty_read,
 333         hung_up_tty_write,
 334         NULL,           /* hung_up_tty_readdir */
 335         hung_up_tty_select,
 336         hung_up_tty_ioctl,
 337         NULL,           /* hung_up_tty_mmap */
 338         NULL,           /* hung_up_tty_open */
 339         tty_release,    /* hung_up_tty_release */
 340         NULL,           /* hung_up_tty_fsync  */
 341         NULL            /* hung_up_tty_fasync */
 342 };
 343 
 344 void do_tty_hangup(struct tty_struct * tty, struct file_operations *fops)
     /*  */
 345 {
 346         int i;
 347         struct file * filp;
 348         struct task_struct *p;
 349 
 350         if (!tty)
 351                 return;
 352         check_tty_count(tty, "do_tty_hangup");
 353         for (filp = first_file, i=0; i<nr_files; i++, filp = filp->f_next) {
 354                 if (!filp->f_count)
 355                         continue;
 356                 if (filp->private_data != tty)
 357                         continue;
 358                 if (filp->f_inode && filp->f_inode->i_rdev == CONSOLE_DEV)
 359                         continue;
 360                 if (filp->f_op != &tty_fops)
 361                         continue;
 362                 tty_fasync(filp->f_inode, filp, 0);
 363                 filp->f_op = fops;
 364         }
 365         
 366         if (tty->ldisc.flush_buffer)
 367                 tty->ldisc.flush_buffer(tty);
 368         if (tty->driver.flush_buffer)
 369                 tty->driver.flush_buffer(tty);
 370         if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
 371             tty->ldisc.write_wakeup)
 372                 (tty->ldisc.write_wakeup)(tty);
 373         wake_up_interruptible(&tty->write_wait);
 374         wake_up_interruptible(&tty->read_wait);
 375 
 376         /*
 377          * Shutdown the current line discipline, and reset it to
 378          * N_TTY.
 379          */
 380         if (tty->ldisc.num != ldiscs[N_TTY].num) {
 381                 if (tty->ldisc.close)
 382                         (tty->ldisc.close)(tty);
 383                 tty->ldisc = ldiscs[N_TTY];
 384                 tty->termios->c_line = N_TTY;
 385                 if (tty->ldisc.open) {
 386                         i = (tty->ldisc.open)(tty);
 387                         if (i < 0)
 388                                 printk("do_tty_hangup: N_TTY open: error %d\n",
 389                                        -i);
 390                 }
 391         }
 392         
 393         for_each_task(p) {
 394                 if ((tty->session > 0) && (p->session == tty->session) &&
 395                     p->leader) {
 396                         send_sig(SIGHUP,p,1);
 397                         send_sig(SIGCONT,p,1);
 398                         if (tty->pgrp > 0)
 399                                 p->tty_old_pgrp = tty->pgrp;
 400                 }
 401                 if (p->tty == tty)
 402                         p->tty = NULL;
 403         }
 404         tty->flags = 0;
 405         tty->session = 0;
 406         tty->pgrp = -1;
 407         tty->ctrl_status = 0;
 408         if (tty->driver.flags & TTY_DRIVER_RESET_TERMIOS)
 409                 *tty->termios = tty->driver.init_termios;
 410         if (tty->driver.hangup)
 411                 (tty->driver.hangup)(tty);
 412 }
 413 
 414 void tty_hangup(struct tty_struct * tty)
     /*  */
 415 {
 416 #ifdef TTY_DEBUG_HANGUP
 417         printk("%s hangup...\n", tty_name(tty));
 418 #endif
 419         do_tty_hangup(tty, &hung_up_tty_fops);
 420 }
 421 
 422 void tty_vhangup(struct tty_struct * tty)
     /*  */
 423 {
 424 #ifdef TTY_DEBUG_HANGUP
 425         printk("%s vhangup...\n", tty_name(tty));
 426 #endif
 427         do_tty_hangup(tty, &hung_up_tty_fops);
 428 }
 429 
 430 int tty_hung_up_p(struct file * filp)
     /*  */
 431 {
 432         return (filp->f_op == &hung_up_tty_fops);
 433 }
 434 
 435 /*
 436  * This function is typically called only by the session leader, when
 437  * it wants to disassociate itself from its controlling tty.
 438  *
 439  * It performs the following functions:
 440  *      (1)  Sends a SIGHUP and SIGCONT to the foreground process group
 441  *      (2)  Clears the tty from being controlling the session
 442  *      (3)  Clears the controlling tty for all processes in the
 443  *              session group.
 444  */
 445 void disassociate_ctty(int priv)
     /*  */
 446 {
 447         struct tty_struct *tty = current->tty;
 448         struct task_struct *p;
 449 
 450         if (!tty) {
 451                 if (current->tty_old_pgrp) {
 452                         kill_pg(current->tty_old_pgrp, SIGHUP, priv);
 453                         kill_pg(current->tty_old_pgrp, SIGCONT, priv);
 454                 }
 455                 return;
 456         }
 457         if (tty->pgrp > 0) {
 458                 kill_pg(tty->pgrp, SIGHUP, priv);
 459                 kill_pg(tty->pgrp, SIGCONT, priv);
 460         }
 461 
 462         tty->session = 0;
 463         tty->pgrp = -1;
 464 
 465         for_each_task(p)
 466                 if (p->session == current->session)
 467                         p->tty = NULL;
 468 }
 469 
 470 /*
 471  * Sometimes we want to wait until a particular VT has been activated. We
 472  * do it in a very simple manner. Everybody waits on a single queue and
 473  * get woken up at once. Those that are satisfied go on with their business,
 474  * while those not ready go back to sleep. Seems overkill to add a wait
 475  * to each vt just for this - usually this does nothing!
 476  */
 477 static struct wait_queue *vt_activate_queue = NULL;
 478 
 479 /*
 480  * Sleeps until a vt is activated, or the task is interrupted. Returns
 481  * 0 if activation, -1 if interrupted.
 482  */
 483 int vt_waitactive(void)
     /*  */
 484 {
 485         interruptible_sleep_on(&vt_activate_queue);
 486         return (current->signal & ~current->blocked) ? -1 : 0;
 487 }
 488 
 489 #define vt_wake_waitactive() wake_up(&vt_activate_queue)
 490 
 491 void reset_vc(unsigned int new_console)
     /*  */
 492 {
 493         vt_cons[new_console]->vc_mode = KD_TEXT;
 494         kbd_table[new_console].kbdmode = VC_XLATE;
 495         vt_cons[new_console]->vt_mode.mode = VT_AUTO;
 496         vt_cons[new_console]->vt_mode.waitv = 0;
 497         vt_cons[new_console]->vt_mode.relsig = 0;
 498         vt_cons[new_console]->vt_mode.acqsig = 0;
 499         vt_cons[new_console]->vt_mode.frsig = 0;
 500         vt_cons[new_console]->vt_pid = -1;
 501         vt_cons[new_console]->vt_newvt = -1;
 502 }
 503 
 504 /*
 505  * Performs the back end of a vt switch
 506  */
 507 void complete_change_console(unsigned int new_console)
     /*  */
 508 {
 509         unsigned char old_vc_mode;
 510 
 511         if (new_console == fg_console)
 512                 return;
 513         if (!vc_cons_allocated(new_console))
 514                 return;
 515         last_console = fg_console;
 516 
 517         /*
 518          * If we're switching, we could be going from KD_GRAPHICS to
 519          * KD_TEXT mode or vice versa, which means we need to blank or
 520          * unblank the screen later.
 521          */
 522         old_vc_mode = vt_cons[fg_console]->vc_mode;
 523         update_screen(new_console);
 524 
 525         /*
 526          * If this new console is under process control, send it a signal
 527          * telling it that it has acquired. Also check if it has died and
 528          * clean up (similar to logic employed in change_console())
 529          */
 530         if (vt_cons[new_console]->vt_mode.mode == VT_PROCESS)
 531         {
 532                 /*
 533                  * Send the signal as privileged - kill_proc() will
 534                  * tell us if the process has gone or something else
 535                  * is awry
 536                  */
 537                 if (kill_proc(vt_cons[new_console]->vt_pid,
 538                               vt_cons[new_console]->vt_mode.acqsig,
 539                               1) != 0)
 540                 {
 541                 /*
 542                  * The controlling process has died, so we revert back to
 543                  * normal operation. In this case, we'll also change back
 544                  * to KD_TEXT mode. I'm not sure if this is strictly correct
 545                  * but it saves the agony when the X server dies and the screen
 546                  * remains blanked due to KD_GRAPHICS! It would be nice to do
 547                  * this outside of VT_PROCESS but there is no single process
 548                  * to account for and tracking tty count may be undesirable.
 549                  */
 550                         reset_vc(new_console);
 551                 }
 552         }
 553 
 554         /*
 555          * We do this here because the controlling process above may have
 556          * gone, and so there is now a new vc_mode
 557          */
 558         if (old_vc_mode != vt_cons[new_console]->vc_mode)
 559         {
 560                 if (vt_cons[new_console]->vc_mode == KD_TEXT)
 561                         do_unblank_screen();
 562                 else
 563                         do_blank_screen(1);
 564         }
 565 
 566         /*
 567          * Wake anyone waiting for their VT to activate
 568          */
 569         vt_wake_waitactive();
 570         return;
 571 }
 572 
 573 /*
 574  * Performs the front-end of a vt switch
 575  */
 576 void change_console(unsigned int new_console)
     /*  */
 577 {
 578         if (new_console == fg_console)
 579                 return;
 580         if (!vc_cons_allocated(new_console))
 581                 return;
 582 
 583         /*
 584          * If this vt is in process mode, then we need to handshake with
 585          * that process before switching. Essentially, we store where that
 586          * vt wants to switch to and wait for it to tell us when it's done
 587          * (via VT_RELDISP ioctl).
 588          *
 589          * We also check to see if the controlling process still exists.
 590          * If it doesn't, we reset this vt to auto mode and continue.
 591          * This is a cheap way to track process control. The worst thing
 592          * that can happen is: we send a signal to a process, it dies, and
 593          * the switch gets "lost" waiting for a response; hopefully, the
 594          * user will try again, we'll detect the process is gone (unless
 595          * the user waits just the right amount of time :-) and revert the
 596          * vt to auto control.
 597          */
 598         if (vt_cons[fg_console]->vt_mode.mode == VT_PROCESS)
 599         {
 600                 /*
 601                  * Send the signal as privileged - kill_proc() will
 602                  * tell us if the process has gone or something else
 603                  * is awry
 604                  */
 605                 if (kill_proc(vt_cons[fg_console]->vt_pid,
 606                               vt_cons[fg_console]->vt_mode.relsig,
 607                               1) == 0)
 608                 {
 609                         /*
 610                          * It worked. Mark the vt to switch to and
 611                          * return. The process needs to send us a
 612                          * VT_RELDISP ioctl to complete the switch.
 613                          */
 614                         vt_cons[fg_console]->vt_newvt = new_console;
 615                         return;
 616                 }
 617 
 618                 /*
 619                  * The controlling process has died, so we revert back to
 620                  * normal operation. In this case, we'll also change back
 621                  * to KD_TEXT mode. I'm not sure if this is strictly correct
 622                  * but it saves the agony when the X server dies and the screen
 623                  * remains blanked due to KD_GRAPHICS! It would be nice to do
 624                  * this outside of VT_PROCESS but there is no single process
 625                  * to account for and tracking tty count may be undesirable.
 626                  */
 627                 reset_vc(fg_console);
 628 
 629                 /*
 630                  * Fall through to normal (VT_AUTO) handling of the switch...
 631                  */
 632         }
 633 
 634         /*
 635          * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
 636          */
 637         if (vt_cons[fg_console]->vc_mode == KD_GRAPHICS)
 638                 return;
 639 
 640         complete_change_console(new_console);
 641 }
 642 
 643 void wait_for_keypress(void)
     /*  */
 644 {
 645         sleep_on(&keypress_wait);
 646 }
 647 
 648 void stop_tty(struct tty_struct *tty)
     /*  */
 649 {
 650         if (tty->stopped)
 651                 return;
 652         tty->stopped = 1;
 653         if (tty->link && tty->link->packet) {
 654                 tty->ctrl_status &= ~TIOCPKT_START;
 655                 tty->ctrl_status |= TIOCPKT_STOP;
 656                 wake_up_interruptible(&tty->link->read_wait);
 657         }
 658         if (tty->driver.stop)
 659                 (tty->driver.stop)(tty);
 660 }
 661 
 662 void start_tty(struct tty_struct *tty)
     /*  */
 663 {
 664         if (!tty->stopped)
 665                 return;
 666         tty->stopped = 0;
 667         if (tty->link && tty->link->packet) {
 668                 tty->ctrl_status &= ~TIOCPKT_STOP;
 669                 tty->ctrl_status |= TIOCPKT_START;
 670                 wake_up_interruptible(&tty->link->read_wait);
 671         }
 672         if (tty->driver.start)
 673                 (tty->driver.start)(tty);
 674         if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
 675             tty->ldisc.write_wakeup)
 676                 (tty->ldisc.write_wakeup)(tty);
 677         wake_up_interruptible(&tty->write_wait);
 678 }
 679 
 680 static int tty_read(struct inode * inode, struct file * file, char * buf, int count)
     /*  */
 681 {
 682         int i;
 683         struct tty_struct * tty;
 684 
 685         tty = (struct tty_struct *)file->private_data;
 686         if (tty_paranoia_check(tty, inode->i_rdev, "tty_read"))
 687                 return -EIO;
 688         if (!tty || (tty->flags & (1 << TTY_IO_ERROR)))
 689                 return -EIO;
 690 
 691         /* This check not only needs to be done before reading, but also
 692            whenever read_chan() gets woken up after sleeping, so I've
 693            moved it to there.  This should only be done for the N_TTY
 694            line discipline, anyway.  Same goes for write_chan(). -- jlc. */
 695 #if 0
 696         if ((inode->i_rdev != CONSOLE_DEV) && /* don't stop on /dev/console */
 697             (tty->pgrp > 0) &&
 698             (current->tty == tty) &&
 699             (tty->pgrp != current->pgrp))
 700                 if (is_ignored(SIGTTIN) || is_orphaned_pgrp(current->pgrp))
 701                         return -EIO;
 702                 else {
 703                         (void) kill_pg(current->pgrp, SIGTTIN, 1);
 704                         return -ERESTARTSYS;
 705                 }
 706 #endif
 707         if (tty->ldisc.read)
 708                 /* XXX casts are for what kernel-wide prototypes should be. */
 709                 i = (tty->ldisc.read)(tty,file,(unsigned char *)buf,(unsigned int)count);
 710         else
 711                 i = -EIO;
 712         if (i > 0)
 713                 inode->i_atime = CURRENT_TIME;
 714         return i;
 715 }
 716 
 717 static int tty_write(struct inode * inode, struct file * file, char * buf, int count)
     /*  */
 718 {
 719         int i, is_console;
 720         struct tty_struct * tty;
 721 
 722         is_console = (inode->i_rdev == CONSOLE_DEV);
 723 
 724         if (is_console && redirect)
 725                 tty = redirect;
 726         else
 727                 tty = (struct tty_struct *)file->private_data;
 728         if (tty_paranoia_check(tty, inode->i_rdev, "tty_write"))
 729                 return -EIO;
 730         if (!tty || !tty->driver.write || (tty->flags & (1 << TTY_IO_ERROR)))
 731                 return -EIO;
 732 #if 0
 733         if (!is_console && L_TOSTOP(tty) && (tty->pgrp > 0) &&
 734             (current->tty == tty) && (tty->pgrp != current->pgrp)) {
 735                 if (is_orphaned_pgrp(current->pgrp))
 736                         return -EIO;
 737                 if (!is_ignored(SIGTTOU)) {
 738                         (void) kill_pg(current->pgrp, SIGTTOU, 1);
 739                         return -ERESTARTSYS;
 740                 }
 741         }
 742 #endif
 743         if (tty->ldisc.write)
 744                 /* XXX casts are for what kernel-wide prototypes should be. */
 745                 i = (tty->ldisc.write)(tty,file,(unsigned char *)buf,(unsigned int)count);
 746         else
 747                 i = -EIO;
 748         if (i > 0)
 749                 inode->i_mtime = CURRENT_TIME;
 750         return i;
 751 }
 752 
 753 /*
 754  * This is so ripe with races that you should *really* not touch this
 755  * unless you know exactly what you are doing. All the changes have to be
 756  * made atomically, or there may be incorrect pointers all over the place.
 757  */
 758 static int init_dev(dev_t device, struct tty_struct **ret_tty)
     /*  */
 759 {
 760         struct tty_struct *tty, **tty_loc, *o_tty, **o_tty_loc;
 761         struct termios *tp, **tp_loc, *o_tp, **o_tp_loc;
 762         struct termios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
 763         struct tty_driver *driver;      
 764         int retval;
 765         int idx;
 766 
 767         driver = get_tty_driver(device);
 768         if (!driver)
 769                 return -ENODEV;
 770 
 771         idx = MINOR(device) - driver->minor_start;
 772         tty = o_tty = NULL;
 773         tp = o_tp = NULL;
 774         ltp = o_ltp = NULL;
 775         o_tty_loc = NULL;
 776         o_tp_loc = o_ltp_loc = NULL;
 777 
 778         tty_loc = &driver->table[idx];
 779         tp_loc = &driver->termios[idx];
 780         ltp_loc = &driver->termios_locked[idx];
 781 
 782 repeat:
 783         retval = -EAGAIN;
 784         if (driver->type == TTY_DRIVER_TYPE_PTY &&
 785             driver->subtype == PTY_TYPE_MASTER &&
 786             *tty_loc && (*tty_loc)->count)
 787                 goto end_init;
 788         retval = -ENOMEM;
 789         if (!*tty_loc && !tty) {
 790                 if (!(tty = (struct tty_struct*) get_free_page(GFP_KERNEL)))
 791                         goto end_init;
 792                 initialize_tty_struct(tty);
 793                 tty->device = device;
 794                 tty->driver = *driver;
 795                 goto repeat;
 796         }
 797         if (!*tp_loc && !tp) {
 798                 tp = (struct termios *) kmalloc(sizeof(struct termios),
 799                                                 GFP_KERNEL);
 800                 if (!tp)
 801                         goto end_init;
 802                 *tp = driver->init_termios;
 803                 goto repeat;
 804         }
 805         if (!*ltp_loc && !ltp) {
 806                 ltp = (struct termios *) kmalloc(sizeof(struct termios),
 807                                                  GFP_KERNEL);
 808                 if (!ltp)
 809                         goto end_init;
 810                 memset(ltp, 0, sizeof(struct termios));
 811                 goto repeat;
 812         }
 813         if (driver->type == TTY_DRIVER_TYPE_PTY) {
 814                 o_tty_loc = &driver->other->table[idx];
 815                 o_tp_loc = &driver->other->termios[idx];
 816                 o_ltp_loc = &driver->other->termios_locked[idx];
 817 
 818                 if (!*o_tty_loc && !o_tty) {
 819                         dev_t   o_device;
 820                         
 821                         o_tty = (struct tty_struct *)
 822                                 get_free_page(GFP_KERNEL);
 823                         if (!o_tty)
 824                                 goto end_init;
 825                         o_device = MKDEV(driver->other->major,
 826                                          driver->other->minor_start + idx);
 827                         initialize_tty_struct(o_tty);
 828                         o_tty->device = o_device;
 829                         o_tty->driver = *driver->other;
 830                         goto repeat;
 831                 }
 832                 if (!*o_tp_loc && !o_tp) {
 833                         o_tp = (struct termios *)
 834                                 kmalloc(sizeof(struct termios), GFP_KERNEL);
 835                         if (!o_tp)
 836                                 goto end_init;
 837                         *o_tp = driver->other->init_termios;
 838                         goto repeat;
 839                 }
 840                 if (!*o_ltp_loc && !o_ltp) {
 841                         o_ltp = (struct termios *)
 842                                 kmalloc(sizeof(struct termios), GFP_KERNEL);
 843                         if (!o_ltp)
 844                                 goto end_init;
 845                         memset(o_ltp, 0, sizeof(struct termios));
 846                         goto repeat;
 847                 }
 848                 
 849         }
 850         /* Now we have allocated all the structures: update all the pointers.. */
 851         if (!*tp_loc) {
 852                 *tp_loc = tp;
 853                 tp = NULL;
 854         }
 855         if (!*ltp_loc) {
 856                 *ltp_loc = ltp;
 857                 ltp = NULL;
 858         }
 859         if (!*tty_loc) {
 860                 tty->termios = *tp_loc;
 861                 tty->termios_locked = *ltp_loc;
 862                 *tty_loc = tty;
 863                 (*driver->refcount)++;
 864                 (*tty_loc)->count++;
 865                 if (tty->ldisc.open) {
 866                         retval = (tty->ldisc.open)(tty);
 867                         if (retval < 0) {
 868                                 (*tty_loc)->count--;
 869                                 tty = NULL;
 870                                 goto end_init;
 871                         }
 872                 }
 873                 tty = NULL;
 874         } else
 875                 (*tty_loc)->count++;
 876         if (driver->type == TTY_DRIVER_TYPE_PTY) {
 877                 if (!*o_tp_loc) {
 878                         *o_tp_loc = o_tp;
 879                         o_tp = NULL;
 880                 }
 881                 if (!*o_ltp_loc) {
 882                         *o_ltp_loc = o_ltp;
 883                         o_ltp = NULL;
 884                 }
 885                 if (!*o_tty_loc) {
 886                         o_tty->termios = *o_tp_loc;
 887                         o_tty->termios_locked = *o_ltp_loc;
 888                         *o_tty_loc = o_tty;
 889                         (*driver->other->refcount)++;
 890                         if (o_tty->ldisc.open) {
 891                                 retval = (o_tty->ldisc.open)(o_tty);
 892                                 if (retval < 0) {
 893                                         (*tty_loc)->count--;
 894                                         o_tty = NULL;
 895                                         goto end_init;
 896                                 }
 897                         }
 898                         o_tty = NULL;
 899                 }
 900                 (*tty_loc)->link = *o_tty_loc;
 901                 (*o_tty_loc)->link = *tty_loc;
 902                 if (driver->subtype == PTY_TYPE_MASTER)
 903                         (*o_tty_loc)->count++;
 904         }
 905         (*tty_loc)->driver = *driver;
 906         *ret_tty = *tty_loc;
 907         retval = 0;
 908 end_init:
 909         if (tty)
 910                 free_page((unsigned long) tty);
 911         if (o_tty)
 912                 free_page((unsigned long) o_tty);
 913         if (tp)
 914                 kfree_s(tp, sizeof(struct termios));
 915         if (o_tp)
 916                 kfree_s(o_tp, sizeof(struct termios));
 917         if (ltp)
 918                 kfree_s(ltp, sizeof(struct termios));
 919         if (o_ltp)
 920                 kfree_s(o_ltp, sizeof(struct termios));
 921         return retval;
 922 }
 923 
 924 /*
 925  * Even releasing the tty structures is a tricky business.. We have
 926  * to be very careful that the structures are all released at the
 927  * same time, as interrupts might otherwise get the wrong pointers.
 928  */
 929 static void release_dev(struct file * filp)
     /*  */
 930 {
 931         struct tty_struct *tty, *o_tty;
 932         struct termios *tp, *o_tp, *ltp, *o_ltp;
 933         struct task_struct **p;
 934         int     idx;
 935         
 936         tty = (struct tty_struct *)filp->private_data;
 937         if (tty_paranoia_check(tty, filp->f_inode->i_rdev, "release_dev"))
 938                 return;
 939 
 940         check_tty_count(tty, "release_dev");
 941 
 942         tty_fasync(filp->f_inode, filp, 0);
 943 
 944         tp = tty->termios;
 945         ltp = tty->termios_locked;
 946 
 947         idx = MINOR(tty->device) - tty->driver.minor_start;
 948 #ifdef TTY_PARANOIA_CHECK
 949         if (idx < 0 || idx >= tty->driver.num) {
 950                 printk("release_dev: bad idx when trying to free (%d, %d)\n",
 951                        MAJOR(tty->device), MINOR(tty->device));
 952                 return;
 953         }
 954         if (tty != tty->driver.table[idx]) {
 955                 printk("release_dev: driver.table[%d] not tty for (%d, %d)\n",
 956                        idx, MAJOR(tty->device), MINOR(tty->device));
 957                 return;
 958         }
 959         if (tp != tty->driver.termios[idx]) {
 960                 printk("release_dev: driver.termios[%d] not termios for (%d, %d)\n",
 961                        idx, MAJOR(tty->device), MINOR(tty->device));
 962                 return;
 963         }
 964         if (ltp != tty->driver.termios_locked[idx]) {
 965                 printk("release_dev: driver.termios_locked[%d] not termios_locked for (%d, %d)\n",
 966                        idx, MAJOR(tty->device), MINOR(tty->device));
 967                 return;
 968         }
 969 #endif
 970 
 971 #ifdef TTY_DEBUG_HANGUP
 972         printk("release_dev of %s (tty count=%d)...", tty_name(tty),
 973                tty->count);
 974 #endif
 975 
 976         o_tty = tty->link;
 977         o_tp = (o_tty) ? o_tty->termios : NULL;
 978         o_ltp = (o_tty) ? o_tty->termios_locked : NULL;
 979 
 980 #ifdef TTY_PARANOIA_CHECK
 981         if (tty->driver.other) {
 982                 if (o_tty != tty->driver.other->table[idx]) {
 983                         printk("release_dev: other->table[%d] not o_tty for (%d, %d)\n",
 984                                idx, MAJOR(tty->device), MINOR(tty->device));
 985                         return;
 986                 }
 987                 if (o_tp != tty->driver.other->termios[idx]) {
 988                         printk("release_dev: other->termios[%d] not o_termios for (%d, %d)\n",
 989                                idx, MAJOR(tty->device), MINOR(tty->device));
 990                         return;
 991                 }
 992                 if (o_ltp != tty->driver.other->termios_locked[idx]) {
 993                         printk("release_dev: other->termios_locked[%d] not o_termios_locked for (%d, %d)\n",
 994                                idx, MAJOR(tty->device), MINOR(tty->device));
 995                         return;
 996                 }
 997 
 998                 if (o_tty->link != tty) {
 999                         printk("release_dev: bad pty pointers\n");
1000                         return;
1001                 }
1002         }
1003 #endif
1004         
1005         if (tty->driver.close)
1006                 tty->driver.close(tty, filp);
1007         if (tty->driver.type == TTY_DRIVER_TYPE_PTY &&
1008             tty->driver.subtype == PTY_TYPE_MASTER) {
1009                 if (--tty->link->count < 0) {
1010                         printk("release_dev: bad pty slave count (%d) for %s\n",
1011                                tty->count, tty_name(tty));
1012                         tty->link->count = 0;
1013                 }
1014         }
1015         if (--tty->count < 0) {
1016                 printk("release_dev: bad tty->count (%d) for %s\n",
1017                        tty->count, tty_name(tty));
1018                 tty->count = 0;
1019         }
1020         if (tty->count)
1021                 return;
1022 
1023         if (o_tty) {
1024                 if (o_tty->count)
1025                         return;
1026                 tty->driver.other->table[idx] = NULL;
1027                 tty->driver.other->termios[idx] = NULL;
1028                 kfree_s(o_tp, sizeof(struct termios));
1029         }
1030         
1031 #ifdef TTY_DEBUG_HANGUP
1032         printk("freeing tty structure...");
1033 #endif
1034 
1035         /*
1036          * Make sure there aren't any processes that still think this
1037          * tty is their controlling tty.
1038          */
1039         for (p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
1040                 if (*p == 0)
1041                         continue;
1042                 if ((*p)->tty == tty)
1043                         (*p)->tty = NULL;
1044                 if (o_tty && (*p)->tty == o_tty)
1045                         (*p)->tty = NULL;
1046         }
1047 
1048         /*
1049          * Shutdown the current line discipline, and reset it to
1050          * N_TTY.
1051          */
1052         if (tty->ldisc.close)
1053                 (tty->ldisc.close)(tty);
1054         tty->ldisc = ldiscs[N_TTY];
1055         tty->termios->c_line = N_TTY;
1056         if (o_tty) {
1057                 if (o_tty->ldisc.close)
1058                         (o_tty->ldisc.close)(o_tty);
1059                 o_tty->ldisc = ldiscs[N_TTY];
1060                 o_tty->termios->c_line = N_TTY;
1061         }
1062         
1063         tty->driver.table[idx] = NULL;
1064         if (tty->driver.flags & TTY_DRIVER_RESET_TERMIOS) {
1065                 tty->driver.termios[idx] = NULL;
1066                 kfree_s(tp, sizeof(struct termios));
1067         }
1068         if (tty == redirect || o_tty == redirect)
1069                 redirect = NULL;
1070         /*
1071          * Make sure that the tty's task queue isn't activated.  If it
1072          * is, take it out of the linked list.
1073          */
1074         cli();
1075         if (tty->flip.tqueue.sync) {
1076                 struct tq_struct *tq, *prev;
1077 
1078                 for (tq=tq_timer, prev=0; tq; prev=tq, tq=tq->next) {
1079                         if (tq == &tty->flip.tqueue) {
1080                                 if (prev)
1081                                         prev->next = tq->next;
1082                                 else
1083                                         tq_timer = tq->next;
1084                                 break;
1085                         }
1086                 }
1087         }
1088         sti();
1089         tty->magic = 0;
1090         (*tty->driver.refcount)--;
1091         free_page((unsigned long) tty);
1092         filp->private_data = 0;
1093         if (o_tty) {
1094                 o_tty->magic = 0;
1095                 (*o_tty->driver.refcount)--;
1096                 free_page((unsigned long) o_tty);
1097         }
1098 }
1099 
1100 /*
1101  * tty_open and tty_release keep up the tty count that contains the
1102  * number of opens done on a tty. We cannot use the inode-count, as
1103  * different inodes might point to the same tty.
1104  *
1105  * Open-counting is needed for pty masters, as well as for keeping
1106  * track of serial lines: DTR is dropped when the last close happens.
1107  * (This is not done solely through tty->count, now.  - Ted 1/27/92)
1108  *
1109  * The termios state of a pty is reset on first open so that
1110  * settings don't persist across reuse.
1111  */
1112 static int tty_open(struct inode * inode, struct file * filp)
     /*  */
1113 {
1114         struct tty_struct *tty;
1115         int minor;
1116         int noctty, retval;
1117         dev_t device;
1118 
1119 retry_open:
1120         noctty = filp->f_flags & O_NOCTTY;
1121         device = inode->i_rdev;
1122         if (device == TTY_DEV) {
1123                 if (!current->tty)
1124                         return -ENXIO;
1125                 device = current->tty->device;
1126                 /* noctty = 1; */
1127         }
1128         if (device == CONSOLE_DEV) {
1129                 device = MKDEV(TTY_MAJOR, fg_console+1);
1130                 noctty = 1;
1131         }
1132         minor = MINOR(device);
1133         
1134         retval = init_dev(device, &tty);
1135         if (retval)
1136                 return retval;
1137         filp->private_data = tty;
1138         check_tty_count(tty, "tty_open");
1139         if (tty->driver.type == TTY_DRIVER_TYPE_PTY &&
1140             tty->driver.subtype == PTY_TYPE_MASTER)
1141                 noctty = 1;
1142 #ifdef TTY_DEBUG_HANGUP
1143         printk("opening %s...", tty_name(tty));
1144 #endif
1145         if (tty->driver.open)
1146                 retval = tty->driver.open(tty, filp);
1147         else
1148                 retval = -ENODEV;
1149 
1150         if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && !suser())
1151                 retval = -EBUSY;
1152 
1153         if (retval) {
1154 #ifdef TTY_DEBUG_HANGUP
1155                 printk("error %d in opening %s...", retval, tty_name(tty));
1156 #endif
1157 
1158                 release_dev(filp);
1159                 if (retval != -ERESTARTSYS)
1160                         return retval;
1161                 if (current->signal & ~current->blocked)
1162                         return retval;
1163                 schedule();
1164                 /*
1165                  * Need to reset f_op in case a hangup happened.
1166                  */
1167                 filp->f_op = &tty_fops;
1168                 goto retry_open;
1169         }
1170         if (!noctty &&
1171             current->leader &&
1172             !current->tty &&
1173             tty->session == 0) {
1174                 current->tty = tty;
1175                 tty->session = current->session;
1176                 tty->pgrp = current->pgrp;
1177         }
1178         return 0;
1179 }
1180 
1181 /*
1182  * Note that releasing a pty master also releases the child, so
1183  * we have to make the redirection checks after that and on both
1184  * sides of a pty.
1185  */
1186 static void tty_release(struct inode * inode, struct file * filp)
     /*  */
1187 {
1188         release_dev(filp);
1189 }
1190 
1191 static int tty_select(struct inode * inode, struct file * filp, int sel_type, select_table * wait)
     /*  */
1192 {
1193         struct tty_struct * tty;
1194 
1195         tty = (struct tty_struct *)filp->private_data;
1196         if (tty_paranoia_check(tty, inode->i_rdev, "tty_select"))
1197                 return 0;
1198 
1199         if (tty->ldisc.select)
1200                 return (tty->ldisc.select)(tty, inode, filp, sel_type, wait);
1201         return 0;
1202 }
1203 
1204 static int tty_fasync(struct inode * inode, struct file * filp, int on)
     /*  */
1205 {
1206         struct tty_struct * tty;
1207         struct fasync_struct *fa, *prev;
1208 
1209         tty = (struct tty_struct *)filp->private_data;
1210         if (tty_paranoia_check(tty, inode->i_rdev, "tty_fasync"))
1211                 return 0;
1212 
1213         for (fa = tty->fasync, prev = 0; fa; prev= fa, fa = fa->fa_next) {
1214                 if (fa->fa_file == filp)
1215                         break;
1216         }
1217 
1218         if (on) {
1219                 if (fa)
1220                         return 0;
1221                 fa = (struct fasync_struct *)kmalloc(sizeof(struct fasync_struct), GFP_KERNEL);
1222                 if (!fa)
1223                         return -ENOMEM;
1224                 fa->magic = FASYNC_MAGIC;
1225                 fa->fa_file = filp;
1226                 fa->fa_next = tty->fasync;
1227                 tty->fasync = fa;
1228                 if (!tty->read_wait)
1229                         tty->minimum_to_wake = 1;
1230                 if (filp->f_owner == 0) {
1231                         if (tty->pgrp)
1232                                 filp->f_owner = -tty->pgrp;
1233                         else
1234                                 filp->f_owner = current->pid;
1235                 }
1236         } else {
1237                 if (!fa)
1238                         return 0;
1239                 if (prev)
1240                         prev->fa_next = fa->fa_next;
1241                 else
1242                         tty->fasync = fa->fa_next;
1243                 kfree_s(fa, sizeof(struct fasync_struct));
1244                 if (!tty->fasync && !tty->read_wait)
1245                         tty->minimum_to_wake = N_TTY_BUF_SIZE;
1246         }
1247         return 0;       
1248 }
1249 
1250 /*
1251  * XXX does anyone use this anymore?!?
1252  */
1253 static int do_get_ps_info(unsigned long arg)
     /*  */
1254 {
1255         struct tstruct {
1256                 int flag;
1257                 int present[NR_TASKS];
1258                 struct task_struct tasks[NR_TASKS];
1259         };
1260         struct tstruct *ts = (struct tstruct *)arg;
1261         struct task_struct **p;
1262         char *c, *d;
1263         int i, n = 0;
1264         
1265         i = verify_area(VERIFY_WRITE, (void *)arg, sizeof(struct tstruct));
1266         if (i)
1267                 return i;
1268         for (p = &FIRST_TASK ; p <= &LAST_TASK ; p++, n++)
1269                 if (*p)
1270                 {
1271                         c = (char *)(*p);
1272                         d = (char *)(ts->tasks+n);
1273                         for (i=0 ; i<sizeof(struct task_struct) ; i++)
1274                                 put_fs_byte(*c++, d++);
1275                         put_fs_long(1, (unsigned long *)(ts->present+n));
1276                 }
1277                 else    
1278                         put_fs_long(0, (unsigned long *)(ts->present+n));
1279         return(0);                      
1280 }
1281 
1282 static int tty_ioctl(struct inode * inode, struct file * file,
     /*  */
1283                      unsigned int cmd, unsigned long arg)
1284 {
1285         int     retval;
1286         struct tty_struct * tty;
1287         struct tty_struct * real_tty;
1288         struct winsize tmp_ws;
1289         pid_t pgrp;
1290         unsigned char   ch;
1291         char    mbz = 0;
1292         
1293         tty = (struct tty_struct *)file->private_data;
1294         if (tty_paranoia_check(tty, inode->i_rdev, "tty_ioctl"))
1295                 return -EINVAL;
1296 
1297         if (tty->driver.type == TTY_DRIVER_TYPE_PTY &&
1298             tty->driver.subtype == PTY_TYPE_MASTER)
1299                 real_tty = tty->link;
1300         else
1301                 real_tty = tty;
1302 
1303         switch (cmd) {
1304                 case TIOCSTI:
1305                         if ((current->tty != tty) && !suser())
1306                                 return -EPERM;
1307                         retval = verify_area(VERIFY_READ, (void *) arg, 1);
1308                         if (retval)
1309                                 return retval;
1310                         ch = get_fs_byte((char *) arg);
1311                         tty->ldisc.receive_buf(tty, &ch, &mbz, 1);
1312                         return 0;
1313                 case TIOCGWINSZ:
1314                         retval = verify_area(VERIFY_WRITE, (void *) arg,
1315                                              sizeof (struct winsize));
1316                         if (retval)
1317                                 return retval;
1318                         memcpy_tofs((struct winsize *) arg, &tty->winsize,
1319                                     sizeof (struct winsize));
1320                         return 0;
1321                 case TIOCSWINSZ:
1322                         retval = verify_area(VERIFY_READ, (void *) arg,
1323                                              sizeof (struct winsize));
1324                         if (retval)
1325                                 return retval;                  
1326                         memcpy_fromfs(&tmp_ws, (struct winsize *) arg,
1327                                       sizeof (struct winsize));
1328                         if (memcmp(&tmp_ws, &tty->winsize,
1329                                    sizeof(struct winsize))) {
1330                                 if (tty->pgrp > 0)
1331                                         kill_pg(tty->pgrp, SIGWINCH, 1);
1332                                 if ((real_tty->pgrp != tty->pgrp) &&
1333                                     (real_tty->pgrp > 0))
1334                                         kill_pg(real_tty->pgrp, SIGWINCH, 1);
1335                         }
1336                         tty->winsize = tmp_ws;
1337                         real_tty->winsize = tmp_ws;
1338                         return 0;
1339                 case TIOCCONS:
1340                         if (tty->driver.type == TTY_DRIVER_TYPE_CONSOLE) {
1341                                 if (!suser())
1342                                         return -EPERM;
1343                                 redirect = NULL;
1344                                 return 0;
1345                         }
1346                         if (redirect)
1347                                 return -EBUSY;
1348                         redirect = real_tty;
1349                         return 0;
1350                 case FIONBIO:
1351                         retval = verify_area(VERIFY_READ, (void *) arg, sizeof(long));
1352                         if (retval)
1353                                 return retval;
1354                         arg = get_fs_long((unsigned long *) arg);
1355                         if (arg)
1356                                 file->f_flags |= O_NONBLOCK;
1357                         else
1358                                 file->f_flags &= ~O_NONBLOCK;
1359                         return 0;
1360                 case TIOCEXCL:
1361                         set_bit(TTY_EXCLUSIVE, &tty->flags);
1362                         return 0;
1363                 case TIOCNXCL:
1364                         clear_bit(TTY_EXCLUSIVE, &tty->flags);
1365                         return 0;
1366                 case TIOCNOTTY:
1367                         if (current->tty != tty)
1368                                 return -ENOTTY;
1369                         if (current->leader)
1370                                 disassociate_ctty(0);
1371                         current->tty = NULL;
1372                         return 0;
1373                 case TIOCSCTTY:
1374                         if (current->leader &&
1375                             (current->session == tty->session))
1376                                 return 0;
1377                         /*
1378                          * The process must be a session leader and
1379                          * not have a controlling tty already.
1380                          */
1381                         if (!current->leader || current->tty)
1382                                 return -EPERM;
1383                         if (tty->session > 0) {
1384                                 /*
1385                                  * This tty is already the controlling
1386                                  * tty for another session group!
1387                                  */
1388                                 if ((arg == 1) && suser()) {
1389                                         /*
1390                                          * Steal it away
1391                                          */
1392                                         struct task_struct *p;
1393 
1394                                         for_each_task(p)
1395                                                 if (p->tty == tty)
1396                                                         p->tty = NULL;
1397                                 } else
1398                                         return -EPERM;
1399                         }
1400                         current->tty = tty;
1401                         tty->session = current->session;
1402                         tty->pgrp = current->pgrp;
1403                         return 0;
1404                 case TIOCGPGRP:
1405                         /*
1406                          * (tty == real_tty) is a cheap way of
1407                          * testing if the tty is NOT a master pty.
1408                          */
1409                         if (tty == real_tty && current->tty != real_tty)
1410                                 return -ENOTTY;
1411                         retval = verify_area(VERIFY_WRITE, (void *) arg,
1412                                              sizeof (pid_t));
1413                         if (retval)
1414                                 return retval;
1415                         put_fs_long(real_tty->pgrp, (pid_t *) arg);
1416                         return 0;
1417                 case TIOCSPGRP:
1418                         retval = tty_check_change(real_tty);
1419                         if (retval)
1420                                 return retval;
1421                         if (!current->tty ||
1422                             (current->tty != real_tty) ||
1423                             (real_tty->session != current->session))
1424                                 return -ENOTTY;
1425                         pgrp = get_fs_long((pid_t *) arg);
1426                         if (pgrp < 0)
1427                                 return -EINVAL;
1428                         if (session_of_pgrp(pgrp) != current->session)
1429                                 return -EPERM;
1430                         real_tty->pgrp = pgrp;
1431                         return 0;
1432                 case TIOCGETD:
1433                         retval = verify_area(VERIFY_WRITE, (void *) arg,
1434                                              sizeof (unsigned long));
1435                         if (retval)
1436                                 return retval;
1437                         put_fs_long(tty->ldisc.num, (unsigned long *) arg);
1438                         return 0;
1439                 case TIOCSETD:
1440                         retval = tty_check_change(tty);
1441                         if (retval)
1442                                 return retval;
1443                         arg = get_fs_long((unsigned long *) arg);
1444                         return tty_set_ldisc(tty, arg);
1445                 case TIOCLINUX:
1446                         if (current->tty != tty && !suser())
1447                                 return -EPERM;
1448                         retval = verify_area(VERIFY_READ, (void *) arg, 1);
1449                         if (retval)
1450                                 return retval;
1451                         switch (retval = get_fs_byte((char *)arg))
1452                         {
1453                                 case 0: 
1454                                         return do_screendump(arg,0);
1455                                 case 1:
1456                                         printk("Deprecated TIOCLINUX (1) ioctl\n");
1457                                         return do_get_ps_info(arg);
1458 #ifdef CONFIG_SELECTION
1459                                 case 2:
1460                                         return set_selection(arg, tty);
1461                                 case 3:
1462                                         return paste_selection(tty);
1463 #endif /* CONFIG_SELECTION */
1464                                 case 4:
1465                                         do_unblank_screen();
1466                                         return 0;
1467 #ifdef CONFIG_SELECTION
1468                                 case 5:
1469                                         return sel_loadlut(arg);
1470                                 case 6:
1471                         /*
1472                          * Make it possible to react to Shift+Mousebutton.
1473                          * Note that 'shift_state' is an undocumented
1474                          * kernel-internal variable; programs not closely
1475                          * related to the kernel should not use this.
1476                          */
1477                                         put_fs_byte(shift_state,arg);
1478                                         return 0;
1479                                 case 7:
1480                                         put_fs_byte(mouse_reporting(),arg);
1481                                         return 0;
1482 #endif /* CONFIG_SELECTION */
1483                                 case 8: /* second arg is 1 or 2 */
1484                                 case 9: /* both are explained in console.c */
1485                                         return do_screendump(arg,retval-7);
1486                                 case 10:
1487                                         set_vesa_blanking(arg);
1488                                         return 0;
1489                                 default: 
1490                                         return -EINVAL;
1491                         }
1492                 case TIOCTTYGSTRUCT:
1493                         retval = verify_area(VERIFY_WRITE, (void *) arg,
1494                                                 sizeof(struct tty_struct));
1495                         if (retval)
1496                                 return retval;
1497                         memcpy_tofs((struct tty_struct *) arg,
1498                                     tty, sizeof(struct tty_struct));
1499                         return 0;
1500                 default:
1501                         if (tty->driver.ioctl) {
1502                                 retval = (tty->driver.ioctl)(tty, file,
1503                                                              cmd, arg);
1504                                 if (retval != -ENOIOCTLCMD)
1505                                         return retval;
1506                         }
1507                         if (tty->ldisc.ioctl) {
1508                                 retval = (tty->ldisc.ioctl)(tty, file,
1509                                                             cmd, arg);
1510                                 if (retval != -ENOIOCTLCMD)
1511                                         return retval;
1512                         }
1513                         return -EINVAL;
1514                 }
1515 }
1516 
1517 
1518 /*
1519  * This implements the "Secure Attention Key" ---  the idea is to
1520  * prevent trojan horses by killing all processes associated with this
1521  * tty when the user hits the "Secure Attention Key".  Required for
1522  * super-paranoid applications --- see the Orange Book for more details.
1523  * 
1524  * This code could be nicer; ideally it should send a HUP, wait a few
1525  * seconds, then send a INT, and then a KILL signal.  But you then
1526  * have to coordinate with the init process, since all processes associated
1527  * with the current tty must be dead before the new getty is allowed
1528  * to spawn.
1529  */
1530 void do_SAK( struct tty_struct *tty)
     /*  */
1531 {
1532 #ifdef TTY_SOFT_SAK
1533         tty_hangup(tty);
1534 #else
1535         struct task_struct **p;
1536         int session;
1537         int             i;
1538         struct file     *filp;
1539         
1540         if (!tty)
1541                 return;
1542         session  = tty->session;
1543         if (tty->ldisc.flush_buffer)
1544                 tty->ldisc.flush_buffer(tty);
1545         if (tty->driver.flush_buffer)
1546                 tty->driver.flush_buffer(tty);
1547         for (p = &LAST_TASK ; p > &FIRST_TASK ; --p) {
1548                 if (!(*p))
1549                         continue;
1550                 if (((*p)->tty == tty) ||
1551                     ((session > 0) && ((*p)->session == session)))
1552                         send_sig(SIGKILL, *p, 1);
1553                 else {
1554                         for (i=0; i < NR_OPEN; i++) {
1555                                 filp = (*p)->files->fd[i];
1556                                 if (filp && (filp->f_op == &tty_fops) &&
1557                                     (filp->private_data == tty)) {
1558                                         send_sig(SIGKILL, *p, 1);
1559                                         break;
1560                                 }
1561                         }
1562                 }
1563         }
1564 #endif
1565 }
1566 
1567 /*
1568  * This routine is called out of the software interrupt to flush data
1569  * from the flip buffer to the line discipline.
1570  */
1571 static void flush_to_ldisc(void *private_)
     /*  */
1572 {
1573         struct tty_struct *tty = (struct tty_struct *) private_;
1574         unsigned char   *cp;
1575         char            *fp;
1576         int             count;
1577 
1578         if (tty->flip.buf_num) {
1579                 cp = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
1580                 fp = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
1581                 tty->flip.buf_num = 0;
1582 
1583                 cli();
1584                 tty->flip.char_buf_ptr = tty->flip.char_buf;
1585                 tty->flip.flag_buf_ptr = tty->flip.flag_buf;
1586         } else {
1587                 cp = tty->flip.char_buf;
1588                 fp = tty->flip.flag_buf;
1589                 tty->flip.buf_num = 1;
1590 
1591                 cli();
1592                 tty->flip.char_buf_ptr = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
1593                 tty->flip.flag_buf_ptr = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
1594         }
1595         count = tty->flip.count;
1596         tty->flip.count = 0;
1597         sti();
1598         
1599 #if 0
1600         if (count > tty->max_flip_cnt)
1601                 tty->max_flip_cnt = count;
1602 #endif
1603         tty->ldisc.receive_buf(tty, cp, fp, count);
1604 }
1605 
1606 /*
1607  * This subroutine initializes a tty structure.
1608  */
1609 static void initialize_tty_struct(struct tty_struct *tty)
     /*  */
1610 {
1611         memset(tty, 0, sizeof(struct tty_struct));
1612         tty->magic = TTY_MAGIC;
1613         tty->ldisc = ldiscs[N_TTY];
1614         tty->pgrp = -1;
1615         tty->flip.char_buf_ptr = tty->flip.char_buf;
1616         tty->flip.flag_buf_ptr = tty->flip.flag_buf;
1617         tty->flip.tqueue.routine = flush_to_ldisc;
1618         tty->flip.tqueue.data = tty;
1619 }
1620 
1621 /*
1622  * The default put_char routine if the driver did not define one.
1623  */
1624 void tty_default_put_char(struct tty_struct *tty, unsigned char ch)
     /*  */
1625 {
1626         tty->driver.write(tty, 0, &ch, 1);
1627 }
1628 
1629 /*
1630  * Called by a tty driver to register itself.
1631  */
1632 int tty_register_driver(struct tty_driver *driver)
     /*  */
1633 {
1634         int error;
1635 
1636         if (driver->flags & TTY_DRIVER_INSTALLED)
1637                 return 0;
1638 
1639         error = register_chrdev(driver->major, driver->name, &tty_fops);
1640         if (error < 0)
1641                 return error;
1642         else if(driver->major == 0)
1643                 driver->major = error;
1644 
1645         if (!driver->put_char)
1646                 driver->put_char = tty_default_put_char;
1647         
1648         driver->prev = 0;
1649         driver->next = tty_drivers;
1650         if (tty_drivers) tty_drivers->prev = driver;
1651         tty_drivers = driver;
1652         return error;
1653 }
1654 
1655 /*
1656  * Called by a tty driver to unregister itself.
1657  */
1658 int tty_unregister_driver(struct tty_driver *driver)
     /*  */
1659 {
1660         int     retval;
1661         struct tty_driver *p;
1662         int     found = 0;
1663         int     major_inuse = 0;
1664         
1665         if (*driver->refcount)
1666                 return -EBUSY;
1667 
1668         for (p = tty_drivers; p; p = p->next) {
1669                 if (p == driver)
1670                         found++;
1671                 else if (p->major == driver->major)
1672                         major_inuse++;
1673         }
1674 
1675         if (!major_inuse) {
1676                 retval = unregister_chrdev(driver->major, driver->name);
1677                 if (retval)
1678                         return retval;
1679         }
1680 
1681         if (driver->prev)
1682                 driver->prev->next = driver->next;
1683         else
1684                 tty_drivers = driver->next;
1685         
1686         if (driver->next)
1687                 driver->next->prev = driver->prev;
1688 
1689         return 0;
1690 }
1691 
1692 
1693 /*
1694  * Initialize the console device. This is called *early*, so
1695  * we can't necessarily depend on lots of kernel help here.
1696  * Just do some early initializations, and do the complex setup
1697  * later.
1698  */
1699 long console_init(long kmem_start, long kmem_end)
     /*  */
1700 {
1701         /* Setup the default TTY line discipline. */
1702         memset(ldiscs, 0, sizeof(ldiscs));
1703         (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY);
1704 
1705         /*
1706          * Set up the standard termios.  Individual tty drivers may 
1707          * deviate from this; this is used as a template.
1708          */
1709         memset(&tty_std_termios, 0, sizeof(struct termios));
1710         memcpy(tty_std_termios.c_cc, INIT_C_CC, NCCS);
1711         tty_std_termios.c_iflag = ICRNL | IXON;
1712         tty_std_termios.c_oflag = OPOST | ONLCR;
1713         tty_std_termios.c_cflag = B38400 | CS8 | CREAD;
1714         tty_std_termios.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
1715                 ECHOCTL | ECHOKE | IEXTEN;
1716 
1717         /*
1718          * set up the console device so that later boot sequences can 
1719          * inform about problems etc..
1720          */
1721         return con_init(kmem_start);
1722 }
1723 
1724 /*
1725  * Ok, now we can initialize the rest of the tty devices and can count
1726  * on memory allocations, interrupts etc..
1727  */
1728 long tty_init(long kmem_start)
     /*  */
1729 {
1730         if (sizeof(struct tty_struct) > PAGE_SIZE)
1731                 panic("size of tty structure > PAGE_SIZE!");
1732         if (register_chrdev(TTY_MAJOR,"tty",&tty_fops))
1733                 panic("unable to get major %d for tty device", TTY_MAJOR);
1734         if (register_chrdev(TTYAUX_MAJOR,"cua",&tty_fops))
1735                 panic("unable to get major %d for tty device", TTYAUX_MAJOR);
1736 
1737         kmem_start = kbd_init(kmem_start);
1738         kmem_start = rs_init(kmem_start);
1739 #ifdef CONFIG_CYCLADES
1740         kmem_start = cy_init(kmem_start);
1741 #endif
1742         kmem_start = pty_init(kmem_start);
1743         return kmem_start;
1744 }
/* */
root/drivers/char/tty_io.c

DEFINITIONS
