Pileus Git - ~andy/linux/blob - drivers/tty/pty.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *
   4  *  Added support for a Unix98-style ptmx device.
   5  *    -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
   6  *
   7  *  When reading this code see also fs/devpts. In particular note that the
   8  *  driver_data field is used by the devpts side as a binding to the devpts
   9  *  inode.
  10  */
  11
  12 #include <linux/module.h>
  13
  14 #include <linux/errno.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/tty.h>
  17 #include <linux/tty_flip.h>
  18 #include <linux/fcntl.h>
  19 #include <linux/sched.h>
  20 #include <linux/string.h>
  21 #include <linux/major.h>
  22 #include <linux/mm.h>
  23 #include <linux/init.h>
  24 #include <linux/device.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/bitops.h>
  27 #include <linux/devpts_fs.h>
  28 #include <linux/slab.h>
  29
  30 #include <asm/system.h>
  31
  32 #ifdef CONFIG_UNIX98_PTYS
  33 static struct tty_driver *ptm_driver;
  34 static struct tty_driver *pts_driver;
  35 #endif
  36
  37 static void pty_close(struct tty_struct *tty, struct file *filp)
  38 {
  39         BUG_ON(!tty);
  40         if (tty->driver->subtype == PTY_TYPE_MASTER)
  41                 WARN_ON(tty->count > 1);
  42         else {
  43                 if (tty->count > 2)
  44                         return;
  45         }
  46         wake_up_interruptible(&tty->read_wait);
  47         wake_up_interruptible(&tty->write_wait);
  48         tty->packet = 0;
  49         if (!tty->link)
  50                 return;
  51         tty->link->packet = 0;
  52         set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
  53         wake_up_interruptible(&tty->link->read_wait);
  54         wake_up_interruptible(&tty->link->write_wait);
  55         if (tty->driver->subtype == PTY_TYPE_MASTER) {
  56                 set_bit(TTY_OTHER_CLOSED, &tty->flags);
  57 #ifdef CONFIG_UNIX98_PTYS
  58                 if (tty->driver == ptm_driver)
  59                         devpts_pty_kill(tty->link);
  60 #endif
  61                 tty_unlock();
  62                 tty_vhangup(tty->link);
  63                 tty_lock();
  64         }
  65 }
  66
  67 /*
  68  * The unthrottle routine is called by the line discipline to signal
  69  * that it can receive more characters.  For PTY's, the TTY_THROTTLED
  70  * flag is always set, to force the line discipline to always call the
  71  * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
  72  * characters in the queue.  This is necessary since each time this
  73  * happens, we need to wake up any sleeping processes that could be
  74  * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
  75  * for the pty buffer to be drained.
  76  */
  77 static void pty_unthrottle(struct tty_struct *tty)
  78 {
  79         tty_wakeup(tty->link);
  80         set_bit(TTY_THROTTLED, &tty->flags);
  81 }
  82
  83 /**
  84  *      pty_space       -       report space left for writing
  85  *      @to: tty we are writing into
  86  *
  87  *      The tty buffers allow 64K but we sneak a peak and clip at 8K this
  88  *      allows a lot of overspill room for echo and other fun messes to
  89  *      be handled properly
  90  */
  91
  92 static int pty_space(struct tty_struct *to)
  93 {
  94         int n = 8192 - to->buf.memory_used;
  95         if (n < 0)
  96                 return 0;
  97         return n;
  98 }
  99
 100 /**
 101  *      pty_write               -       write to a pty
 102  *      @tty: the tty we write from
 103  *      @buf: kernel buffer of data
 104  *      @count: bytes to write
 105  *
 106  *      Our "hardware" write method. Data is coming from the ldisc which
 107  *      may be in a non sleeping state. We simply throw this at the other
 108  *      end of the link as if we were an IRQ handler receiving stuff for
 109  *      the other side of the pty/tty pair.
 110  */
 111
 112 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
 113 {
 114         struct tty_struct *to = tty->link;
 115
 116         if (tty->stopped)
 117                 return 0;
 118
 119         if (c > 0) {
 120                 /* Stuff the data into the input queue of the other end */
 121                 c = tty_insert_flip_string(to, buf, c);
 122                 /* And shovel */
 123                 if (c) {
 124                         tty_flip_buffer_push(to);
 125                         tty_wakeup(tty);
 126                 }
 127         }
 128         return c;
 129 }
 130
 131 /**
 132  *      pty_write_room  -       write space
 133  *      @tty: tty we are writing from
 134  *
 135  *      Report how many bytes the ldisc can send into the queue for
 136  *      the other device.
 137  */
 138
 139 static int pty_write_room(struct tty_struct *tty)
 140 {
 141         if (tty->stopped)
 142                 return 0;
 143         return pty_space(tty->link);
 144 }
 145
 146 /**
 147  *      pty_chars_in_buffer     -       characters currently in our tx queue
 148  *      @tty: our tty
 149  *
 150  *      Report how much we have in the transmit queue. As everything is
 151  *      instantly at the other end this is easy to implement.
 152  */
 153
 154 static int pty_chars_in_buffer(struct tty_struct *tty)
 155 {
 156         return 0;
 157 }
 158
 159 /* Set the lock flag on a pty */
 160 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
 161 {
 162         int val;
 163         if (get_user(val, arg))
 164                 return -EFAULT;
 165         if (val)
 166                 set_bit(TTY_PTY_LOCK, &tty->flags);
 167         else
 168                 clear_bit(TTY_PTY_LOCK, &tty->flags);
 169         return 0;
 170 }
 171
 172 /* Send a signal to the slave */
 173 static int pty_signal(struct tty_struct *tty, int sig)
 174 {
 175         unsigned long flags;
 176         struct pid *pgrp;
 177
 178         if (tty->link) {
 179                 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
 180                 pgrp = get_pid(tty->link->pgrp);
 181                 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
 182
 183                 kill_pgrp(pgrp, sig, 1);
 184                 put_pid(pgrp);
 185         }
 186         return 0;
 187 }
 188
 189 static void pty_flush_buffer(struct tty_struct *tty)
 190 {
 191         struct tty_struct *to = tty->link;
 192         unsigned long flags;
 193
 194         if (!to)
 195                 return;
 196         /* tty_buffer_flush(to); FIXME */
 197         if (to->packet) {
 198                 spin_lock_irqsave(&tty->ctrl_lock, flags);
 199                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
 200                 wake_up_interruptible(&to->read_wait);
 201                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 202         }
 203 }
 204
 205 static int pty_open(struct tty_struct *tty, struct file *filp)
 206 {
 207         int     retval = -ENODEV;
 208
 209         if (!tty || !tty->link)
 210                 goto out;
 211
 212         retval = -EIO;
 213         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
 214                 goto out;
 215         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
 216                 goto out;
 217         if (tty->link->count != 1)
 218                 goto out;
 219
 220         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
 221         set_bit(TTY_THROTTLED, &tty->flags);
 222         retval = 0;
 223 out:
 224         return retval;
 225 }
 226
 227 static void pty_set_termios(struct tty_struct *tty,
 228                                         struct ktermios *old_termios)
 229 {
 230         tty->termios->c_cflag &= ~(CSIZE | PARENB);
 231         tty->termios->c_cflag |= (CS8 | CREAD);
 232 }
 233
 234 /**
 235  *      pty_do_resize           -       resize event
 236  *      @tty: tty being resized
 237  *      @ws: window size being set.
 238  *
 239  *      Update the termios variables and send the necessary signals to
 240  *      peform a terminal resize correctly
 241  */
 242
 243 int pty_resize(struct tty_struct *tty,  struct winsize *ws)
 244 {
 245         struct pid *pgrp, *rpgrp;
 246         unsigned long flags;
 247         struct tty_struct *pty = tty->link;
 248
 249         /* For a PTY we need to lock the tty side */
 250         mutex_lock(&tty->termios_mutex);
 251         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
 252                 goto done;
 253
 254         /* Get the PID values and reference them so we can
 255            avoid holding the tty ctrl lock while sending signals.
 256            We need to lock these individually however. */
 257
 258         spin_lock_irqsave(&tty->ctrl_lock, flags);
 259         pgrp = get_pid(tty->pgrp);
 260         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 261
 262         spin_lock_irqsave(&pty->ctrl_lock, flags);
 263         rpgrp = get_pid(pty->pgrp);
 264         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
 265
 266         if (pgrp)
 267                 kill_pgrp(pgrp, SIGWINCH, 1);
 268         if (rpgrp != pgrp && rpgrp)
 269                 kill_pgrp(rpgrp, SIGWINCH, 1);
 270
 271         put_pid(pgrp);
 272         put_pid(rpgrp);
 273
 274         tty->winsize = *ws;
 275         pty->winsize = *ws;     /* Never used so will go away soon */
 276 done:
 277         mutex_unlock(&tty->termios_mutex);
 278         return 0;
 279 }
 280
 281 /* Traditional BSD devices */
 282 #ifdef CONFIG_LEGACY_PTYS
 283
 284 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
 285 {
 286         struct tty_struct *o_tty;
 287         int idx = tty->index;
 288         int retval;
 289
 290         o_tty = alloc_tty_struct();
 291         if (!o_tty)
 292                 return -ENOMEM;
 293         if (!try_module_get(driver->other->owner)) {
 294                 /* This cannot in fact currently happen */
 295                 retval = -ENOMEM;
 296                 goto err_free_tty;
 297         }
 298         initialize_tty_struct(o_tty, driver->other, idx);
 299
 300         /* We always use new tty termios data so we can do this
 301            the easy way .. */
 302         retval = tty_init_termios(tty);
 303         if (retval)
 304                 goto err_deinit_tty;
 305
 306         retval = tty_init_termios(o_tty);
 307         if (retval)
 308                 goto err_free_termios;
 309
 310         /*
 311          * Everything allocated ... set up the o_tty structure.
 312          */
 313         driver->other->ttys[idx] = o_tty;
 314         tty_driver_kref_get(driver->other);
 315         if (driver->subtype == PTY_TYPE_MASTER)
 316                 o_tty->count++;
 317         /* Establish the links in both directions */
 318         tty->link   = o_tty;
 319         o_tty->link = tty;
 320
 321         tty_driver_kref_get(driver);
 322         tty->count++;
 323         driver->ttys[idx] = tty;
 324         return 0;
 325 err_free_termios:
 326         tty_free_termios(tty);
 327 err_deinit_tty:
 328         deinitialize_tty_struct(o_tty);
 329         module_put(o_tty->driver->owner);
 330 err_free_tty:
 331         free_tty_struct(o_tty);
 332         return retval;
 333 }
 334
 335 static int pty_bsd_ioctl(struct tty_struct *tty,
 336                          unsigned int cmd, unsigned long arg)
 337 {
 338         switch (cmd) {
 339         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 340                 return pty_set_lock(tty, (int __user *) arg);
 341         case TIOCSIG:    /* Send signal to other side of pty */
 342                 return pty_signal(tty, (int) arg);
 343         }
 344         return -ENOIOCTLCMD;
 345 }
 346
 347 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
 348 module_param(legacy_count, int, 0);
 349
 350 /*
 351  * The master side of a pty can do TIOCSPTLCK and thus
 352  * has pty_bsd_ioctl.
 353  */
 354 static const struct tty_operations master_pty_ops_bsd = {
 355         .install = pty_install,
 356         .open = pty_open,
 357         .close = pty_close,
 358         .write = pty_write,
 359         .write_room = pty_write_room,
 360         .flush_buffer = pty_flush_buffer,
 361         .chars_in_buffer = pty_chars_in_buffer,
 362         .unthrottle = pty_unthrottle,
 363         .set_termios = pty_set_termios,
 364         .ioctl = pty_bsd_ioctl,
 365         .resize = pty_resize
 366 };
 367
 368 static const struct tty_operations slave_pty_ops_bsd = {
 369         .install = pty_install,
 370         .open = pty_open,
 371         .close = pty_close,
 372         .write = pty_write,
 373         .write_room = pty_write_room,
 374         .flush_buffer = pty_flush_buffer,
 375         .chars_in_buffer = pty_chars_in_buffer,
 376         .unthrottle = pty_unthrottle,
 377         .set_termios = pty_set_termios,
 378         .resize = pty_resize
 379 };
 380
 381 static void __init legacy_pty_init(void)
 382 {
 383         struct tty_driver *pty_driver, *pty_slave_driver;
 384
 385         if (legacy_count <= 0)
 386                 return;
 387
 388         pty_driver = alloc_tty_driver(legacy_count);
 389         if (!pty_driver)
 390                 panic("Couldn't allocate pty driver");
 391
 392         pty_slave_driver = alloc_tty_driver(legacy_count);
 393         if (!pty_slave_driver)
 394                 panic("Couldn't allocate pty slave driver");
 395
 396         pty_driver->driver_name = "pty_master";
 397         pty_driver->name = "pty";
 398         pty_driver->major = PTY_MASTER_MAJOR;
 399         pty_driver->minor_start = 0;
 400         pty_driver->type = TTY_DRIVER_TYPE_PTY;
 401         pty_driver->subtype = PTY_TYPE_MASTER;
 402         pty_driver->init_termios = tty_std_termios;
 403         pty_driver->init_termios.c_iflag = 0;
 404         pty_driver->init_termios.c_oflag = 0;
 405         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 406         pty_driver->init_termios.c_lflag = 0;
 407         pty_driver->init_termios.c_ispeed = 38400;
 408         pty_driver->init_termios.c_ospeed = 38400;
 409         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
 410         pty_driver->other = pty_slave_driver;
 411         tty_set_operations(pty_driver, &master_pty_ops_bsd);
 412
 413         pty_slave_driver->driver_name = "pty_slave";
 414         pty_slave_driver->name = "ttyp";
 415         pty_slave_driver->major = PTY_SLAVE_MAJOR;
 416         pty_slave_driver->minor_start = 0;
 417         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
 418         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
 419         pty_slave_driver->init_termios = tty_std_termios;
 420         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 421         pty_slave_driver->init_termios.c_ispeed = 38400;
 422         pty_slave_driver->init_termios.c_ospeed = 38400;
 423         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
 424                                         TTY_DRIVER_REAL_RAW;
 425         pty_slave_driver->other = pty_driver;
 426         tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
 427
 428         if (tty_register_driver(pty_driver))
 429                 panic("Couldn't register pty driver");
 430         if (tty_register_driver(pty_slave_driver))
 431                 panic("Couldn't register pty slave driver");
 432 }
 433 #else
 434 static inline void legacy_pty_init(void) { }
 435 #endif
 436
 437 /* Unix98 devices */
 438 #ifdef CONFIG_UNIX98_PTYS
 439
 440 static struct cdev ptmx_cdev;
 441
 442 static int pty_unix98_ioctl(struct tty_struct *tty,
 443                             unsigned int cmd, unsigned long arg)
 444 {
 445         switch (cmd) {
 446         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 447                 return pty_set_lock(tty, (int __user *)arg);
 448         case TIOCGPTN: /* Get PT Number */
 449                 return put_user(tty->index, (unsigned int __user *)arg);
 450         case TIOCSIG:    /* Send signal to other side of pty */
 451                 return pty_signal(tty, (int) arg);
 452         }
 453
 454         return -ENOIOCTLCMD;
 455 }
 456
 457 /**
 458  *      ptm_unix98_lookup       -       find a pty master
 459  *      @driver: ptm driver
 460  *      @idx: tty index
 461  *
 462  *      Look up a pty master device. Called under the tty_mutex for now.
 463  *      This provides our locking.
 464  */
 465
 466 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
 467                 struct inode *ptm_inode, int idx)
 468 {
 469         /* Master must be open via /dev/ptmx */
 470         return ERR_PTR(-EIO);
 471 }
 472
 473 /**
 474  *      pts_unix98_lookup       -       find a pty slave
 475  *      @driver: pts driver
 476  *      @idx: tty index
 477  *
 478  *      Look up a pty master device. Called under the tty_mutex for now.
 479  *      This provides our locking.
 480  */
 481
 482 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
 483                 struct inode *pts_inode, int idx)
 484 {
 485         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
 486         /* Master must be open before slave */
 487         if (!tty)
 488                 return ERR_PTR(-EIO);
 489         return tty;
 490 }
 491
 492 static void pty_unix98_shutdown(struct tty_struct *tty)
 493 {
 494         tty_driver_remove_tty(tty->driver, tty);
 495         /* We have our own method as we don't use the tty index */
 496         kfree(tty->termios);
 497 }
 498
 499 /* We have no need to install and remove our tty objects as devpts does all
 500    the work for us */
 501
 502 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
 503 {
 504         struct tty_struct *o_tty;
 505         int idx = tty->index;
 506
 507         o_tty = alloc_tty_struct();
 508         if (!o_tty)
 509                 return -ENOMEM;
 510         if (!try_module_get(driver->other->owner)) {
 511                 /* This cannot in fact currently happen */
 512                 goto err_free_tty;
 513         }
 514         initialize_tty_struct(o_tty, driver->other, idx);
 515
 516         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 517         if (tty->termios == NULL)
 518                 goto err_free_mem;
 519         *tty->termios = driver->init_termios;
 520         tty->termios_locked = tty->termios + 1;
 521
 522         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 523         if (o_tty->termios == NULL)
 524                 goto err_free_mem;
 525         *o_tty->termios = driver->other->init_termios;
 526         o_tty->termios_locked = o_tty->termios + 1;
 527
 528         tty_driver_kref_get(driver->other);
 529         if (driver->subtype == PTY_TYPE_MASTER)
 530                 o_tty->count++;
 531         /* Establish the links in both directions */
 532         tty->link   = o_tty;
 533         o_tty->link = tty;
 534         /*
 535          * All structures have been allocated, so now we install them.
 536          * Failures after this point use release_tty to clean up, so
 537          * there's no need to null out the local pointers.
 538          */
 539         tty_driver_kref_get(driver);
 540         tty->count++;
 541         return 0;
 542 err_free_mem:
 543         deinitialize_tty_struct(o_tty);
 544         kfree(o_tty->termios);
 545         kfree(tty->termios);
 546         module_put(o_tty->driver->owner);
 547 err_free_tty:
 548         free_tty_struct(o_tty);
 549         return -ENOMEM;
 550 }
 551
 552 static void ptm_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 553 {
 554 }
 555
 556 static void pts_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 557 {
 558 }
 559
 560 static const struct tty_operations ptm_unix98_ops = {
 561         .lookup = ptm_unix98_lookup,
 562         .install = pty_unix98_install,
 563         .remove = ptm_unix98_remove,
 564         .open = pty_open,
 565         .close = pty_close,
 566         .write = pty_write,
 567         .write_room = pty_write_room,
 568         .flush_buffer = pty_flush_buffer,
 569         .chars_in_buffer = pty_chars_in_buffer,
 570         .unthrottle = pty_unthrottle,
 571         .set_termios = pty_set_termios,
 572         .ioctl = pty_unix98_ioctl,
 573         .shutdown = pty_unix98_shutdown,
 574         .resize = pty_resize
 575 };
 576
 577 static const struct tty_operations pty_unix98_ops = {
 578         .lookup = pts_unix98_lookup,
 579         .install = pty_unix98_install,
 580         .remove = pts_unix98_remove,
 581         .open = pty_open,
 582         .close = pty_close,
 583         .write = pty_write,
 584         .write_room = pty_write_room,
 585         .flush_buffer = pty_flush_buffer,
 586         .chars_in_buffer = pty_chars_in_buffer,
 587         .unthrottle = pty_unthrottle,
 588         .set_termios = pty_set_termios,
 589         .shutdown = pty_unix98_shutdown
 590 };
 591
 592 /**
 593  *      ptmx_open               -       open a unix 98 pty master
 594  *      @inode: inode of device file
 595  *      @filp: file pointer to tty
 596  *
 597  *      Allocate a unix98 pty master device from the ptmx driver.
 598  *
 599  *      Locking: tty_mutex protects the init_dev work. tty->count should
 600  *              protect the rest.
 601  *              allocated_ptys_lock handles the list of free pty numbers
 602  */
 603
 604 static int ptmx_open(struct inode *inode, struct file *filp)
 605 {
 606         struct tty_struct *tty;
 607         int retval;
 608         int index;
 609
 610         nonseekable_open(inode, filp);
 611
 612         retval = tty_alloc_file(filp);
 613         if (retval)
 614                 return retval;
 615
 616         /* find a device that is not in use. */
 617         tty_lock();
 618         index = devpts_new_index(inode);
 619         tty_unlock();
 620         if (index < 0) {
 621                 retval = index;
 622                 goto err_file;
 623         }
 624
 625         mutex_lock(&tty_mutex);
 626         tty_lock();
 627         tty = tty_init_dev(ptm_driver, index);
 628         mutex_unlock(&tty_mutex);
 629
 630         if (IS_ERR(tty)) {
 631                 retval = PTR_ERR(tty);
 632                 goto out;
 633         }
 634
 635         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
 636
 637         tty_add_file(tty, filp);
 638
 639         retval = devpts_pty_new(inode, tty->link);
 640         if (retval)
 641                 goto err_release;
 642
 643         retval = ptm_driver->ops->open(tty, filp);
 644         if (retval)
 645                 goto err_release;
 646
 647         tty_unlock();
 648         return 0;
 649 err_release:
 650         tty_unlock();
 651         tty_release(inode, filp);
 652         return retval;
 653 out:
 654         devpts_kill_index(inode, index);
 655         tty_unlock();
 656 err_file:
 657         tty_free_file(filp);
 658         return retval;
 659 }
 660
 661 static struct file_operations ptmx_fops;
 662
 663 static void __init unix98_pty_init(void)
 664 {
 665         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
 666         if (!ptm_driver)
 667                 panic("Couldn't allocate Unix98 ptm driver");
 668         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
 669         if (!pts_driver)
 670                 panic("Couldn't allocate Unix98 pts driver");
 671
 672         ptm_driver->driver_name = "pty_master";
 673         ptm_driver->name = "ptm";
 674         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
 675         ptm_driver->minor_start = 0;
 676         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
 677         ptm_driver->subtype = PTY_TYPE_MASTER;
 678         ptm_driver->init_termios = tty_std_termios;
 679         ptm_driver->init_termios.c_iflag = 0;
 680         ptm_driver->init_termios.c_oflag = 0;
 681         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 682         ptm_driver->init_termios.c_lflag = 0;
 683         ptm_driver->init_termios.c_ispeed = 38400;
 684         ptm_driver->init_termios.c_ospeed = 38400;
 685         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 686                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
 687         ptm_driver->other = pts_driver;
 688         tty_set_operations(ptm_driver, &ptm_unix98_ops);
 689
 690         pts_driver->driver_name = "pty_slave";
 691         pts_driver->name = "pts";
 692         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
 693         pts_driver->minor_start = 0;
 694         pts_driver->type = TTY_DRIVER_TYPE_PTY;
 695         pts_driver->subtype = PTY_TYPE_SLAVE;
 696         pts_driver->init_termios = tty_std_termios;
 697         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 698         pts_driver->init_termios.c_ispeed = 38400;
 699         pts_driver->init_termios.c_ospeed = 38400;
 700         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 701                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
 702         pts_driver->other = ptm_driver;
 703         tty_set_operations(pts_driver, &pty_unix98_ops);
 704
 705         if (tty_register_driver(ptm_driver))
 706                 panic("Couldn't register Unix98 ptm driver");
 707         if (tty_register_driver(pts_driver))
 708                 panic("Couldn't register Unix98 pts driver");
 709
 710         /* Now create the /dev/ptmx special device */
 711         tty_default_fops(&ptmx_fops);
 712         ptmx_fops.open = ptmx_open;
 713
 714         cdev_init(&ptmx_cdev, &ptmx_fops);
 715         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
 716             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
 717                 panic("Couldn't register /dev/ptmx driver\n");
 718         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
 719 }
 720
 721 #else
 722 static inline void unix98_pty_init(void) { }
 723 #endif
 724
 725 static int __init pty_init(void)
 726 {
 727         legacy_pty_init();
 728         unix98_pty_init();
 729         return 0;
 730 }
 731 module_init(pty_init);