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 #include <linux/mutex.h>
  30
  31
  32 #ifdef CONFIG_UNIX98_PTYS
  33 static struct tty_driver *ptm_driver;
  34 static struct tty_driver *pts_driver;
  35 static DEFINE_MUTEX(devpts_mutex);
  36 #endif
  37
  38 static void pty_close(struct tty_struct *tty, struct file *filp)
  39 {
  40         BUG_ON(!tty);
  41         if (tty->driver->subtype == PTY_TYPE_MASTER)
  42                 WARN_ON(tty->count > 1);
  43         else {
  44                 if (tty->count > 2)
  45                         return;
  46         }
  47         wake_up_interruptible(&tty->read_wait);
  48         wake_up_interruptible(&tty->write_wait);
  49         tty->packet = 0;
  50         /* Review - krefs on tty_link ?? */
  51         if (!tty->link)
  52                 return;
  53         tty->link->packet = 0;
  54         set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
  55         wake_up_interruptible(&tty->link->read_wait);
  56         wake_up_interruptible(&tty->link->write_wait);
  57         if (tty->driver->subtype == PTY_TYPE_MASTER) {
  58                 set_bit(TTY_OTHER_CLOSED, &tty->flags);
  59 #ifdef CONFIG_UNIX98_PTYS
  60                 if (tty->driver == ptm_driver) {
  61                         mutex_lock(&devpts_mutex);
  62                         devpts_pty_kill(tty->link);
  63                         mutex_unlock(&devpts_mutex);
  64                 }
  65 #endif
  66                 tty_unlock(tty);
  67                 tty_vhangup(tty->link);
  68                 tty_lock(tty);
  69         }
  70 }
  71
  72 /*
  73  * The unthrottle routine is called by the line discipline to signal
  74  * that it can receive more characters.  For PTY's, the TTY_THROTTLED
  75  * flag is always set, to force the line discipline to always call the
  76  * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
  77  * characters in the queue.  This is necessary since each time this
  78  * happens, we need to wake up any sleeping processes that could be
  79  * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
  80  * for the pty buffer to be drained.
  81  */
  82 static void pty_unthrottle(struct tty_struct *tty)
  83 {
  84         tty_wakeup(tty->link);
  85         set_bit(TTY_THROTTLED, &tty->flags);
  86 }
  87
  88 /**
  89  *      pty_space       -       report space left for writing
  90  *      @to: tty we are writing into
  91  *
  92  *      The tty buffers allow 64K but we sneak a peak and clip at 8K this
  93  *      allows a lot of overspill room for echo and other fun messes to
  94  *      be handled properly
  95  */
  96
  97 static int pty_space(struct tty_struct *to)
  98 {
  99         int n = 8192 - to->buf.memory_used;
 100         if (n < 0)
 101                 return 0;
 102         return n;
 103 }
 104
 105 /**
 106  *      pty_write               -       write to a pty
 107  *      @tty: the tty we write from
 108  *      @buf: kernel buffer of data
 109  *      @count: bytes to write
 110  *
 111  *      Our "hardware" write method. Data is coming from the ldisc which
 112  *      may be in a non sleeping state. We simply throw this at the other
 113  *      end of the link as if we were an IRQ handler receiving stuff for
 114  *      the other side of the pty/tty pair.
 115  */
 116
 117 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
 118 {
 119         struct tty_struct *to = tty->link;
 120
 121         if (tty->stopped)
 122                 return 0;
 123
 124         if (c > 0) {
 125                 /* Stuff the data into the input queue of the other end */
 126                 c = tty_insert_flip_string(to, buf, c);
 127                 /* And shovel */
 128                 if (c) {
 129                         tty_flip_buffer_push(to);
 130                         tty_wakeup(tty);
 131                 }
 132         }
 133         return c;
 134 }
 135
 136 /**
 137  *      pty_write_room  -       write space
 138  *      @tty: tty we are writing from
 139  *
 140  *      Report how many bytes the ldisc can send into the queue for
 141  *      the other device.
 142  */
 143
 144 static int pty_write_room(struct tty_struct *tty)
 145 {
 146         if (tty->stopped)
 147                 return 0;
 148         return pty_space(tty->link);
 149 }
 150
 151 /**
 152  *      pty_chars_in_buffer     -       characters currently in our tx queue
 153  *      @tty: our tty
 154  *
 155  *      Report how much we have in the transmit queue. As everything is
 156  *      instantly at the other end this is easy to implement.
 157  */
 158
 159 static int pty_chars_in_buffer(struct tty_struct *tty)
 160 {
 161         return 0;
 162 }
 163
 164 /* Set the lock flag on a pty */
 165 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
 166 {
 167         int val;
 168         if (get_user(val, arg))
 169                 return -EFAULT;
 170         if (val)
 171                 set_bit(TTY_PTY_LOCK, &tty->flags);
 172         else
 173                 clear_bit(TTY_PTY_LOCK, &tty->flags);
 174         return 0;
 175 }
 176
 177 /* Send a signal to the slave */
 178 static int pty_signal(struct tty_struct *tty, int sig)
 179 {
 180         unsigned long flags;
 181         struct pid *pgrp;
 182
 183         if (tty->link) {
 184                 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
 185                 pgrp = get_pid(tty->link->pgrp);
 186                 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
 187
 188                 kill_pgrp(pgrp, sig, 1);
 189                 put_pid(pgrp);
 190         }
 191         return 0;
 192 }
 193
 194 static void pty_flush_buffer(struct tty_struct *tty)
 195 {
 196         struct tty_struct *to = tty->link;
 197         unsigned long flags;
 198
 199         if (!to)
 200                 return;
 201         /* tty_buffer_flush(to); FIXME */
 202         if (to->packet) {
 203                 spin_lock_irqsave(&tty->ctrl_lock, flags);
 204                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
 205                 wake_up_interruptible(&to->read_wait);
 206                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 207         }
 208 }
 209
 210 static int pty_open(struct tty_struct *tty, struct file *filp)
 211 {
 212         int     retval = -ENODEV;
 213
 214         if (!tty || !tty->link)
 215                 goto out;
 216
 217         retval = -EIO;
 218         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
 219                 goto out;
 220         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
 221                 goto out;
 222         if (tty->link->count != 1)
 223                 goto out;
 224
 225         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
 226         set_bit(TTY_THROTTLED, &tty->flags);
 227         retval = 0;
 228 out:
 229         return retval;
 230 }
 231
 232 static void pty_set_termios(struct tty_struct *tty,
 233                                         struct ktermios *old_termios)
 234 {
 235         tty->termios->c_cflag &= ~(CSIZE | PARENB);
 236         tty->termios->c_cflag |= (CS8 | CREAD);
 237 }
 238
 239 /**
 240  *      pty_do_resize           -       resize event
 241  *      @tty: tty being resized
 242  *      @ws: window size being set.
 243  *
 244  *      Update the termios variables and send the necessary signals to
 245  *      peform a terminal resize correctly
 246  */
 247
 248 int pty_resize(struct tty_struct *tty,  struct winsize *ws)
 249 {
 250         struct pid *pgrp, *rpgrp;
 251         unsigned long flags;
 252         struct tty_struct *pty = tty->link;
 253
 254         /* For a PTY we need to lock the tty side */
 255         mutex_lock(&tty->termios_mutex);
 256         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
 257                 goto done;
 258
 259         /* Get the PID values and reference them so we can
 260            avoid holding the tty ctrl lock while sending signals.
 261            We need to lock these individually however. */
 262
 263         spin_lock_irqsave(&tty->ctrl_lock, flags);
 264         pgrp = get_pid(tty->pgrp);
 265         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 266
 267         spin_lock_irqsave(&pty->ctrl_lock, flags);
 268         rpgrp = get_pid(pty->pgrp);
 269         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
 270
 271         if (pgrp)
 272                 kill_pgrp(pgrp, SIGWINCH, 1);
 273         if (rpgrp != pgrp && rpgrp)
 274                 kill_pgrp(rpgrp, SIGWINCH, 1);
 275
 276         put_pid(pgrp);
 277         put_pid(rpgrp);
 278
 279         tty->winsize = *ws;
 280         pty->winsize = *ws;     /* Never used so will go away soon */
 281 done:
 282         mutex_unlock(&tty->termios_mutex);
 283         return 0;
 284 }
 285
 286 /* Traditional BSD devices */
 287 #ifdef CONFIG_LEGACY_PTYS
 288
 289 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
 290 {
 291         struct tty_struct *o_tty;
 292         int idx = tty->index;
 293         int retval;
 294
 295         o_tty = alloc_tty_struct();
 296         if (!o_tty)
 297                 return -ENOMEM;
 298         if (!try_module_get(driver->other->owner)) {
 299                 /* This cannot in fact currently happen */
 300                 retval = -ENOMEM;
 301                 goto err_free_tty;
 302         }
 303         initialize_tty_struct(o_tty, driver->other, idx);
 304
 305         /* We always use new tty termios data so we can do this
 306            the easy way .. */
 307         retval = tty_init_termios(tty);
 308         if (retval)
 309                 goto err_deinit_tty;
 310
 311         retval = tty_init_termios(o_tty);
 312         if (retval)
 313                 goto err_free_termios;
 314
 315         /*
 316          * Everything allocated ... set up the o_tty structure.
 317          */
 318         driver->other->ttys[idx] = o_tty;
 319         tty_driver_kref_get(driver->other);
 320         if (driver->subtype == PTY_TYPE_MASTER)
 321                 o_tty->count++;
 322         /* Establish the links in both directions */
 323         tty->link   = o_tty;
 324         o_tty->link = tty;
 325
 326         tty_driver_kref_get(driver);
 327         tty->count++;
 328         driver->ttys[idx] = tty;
 329         return 0;
 330 err_free_termios:
 331         tty_free_termios(tty);
 332 err_deinit_tty:
 333         deinitialize_tty_struct(o_tty);
 334         module_put(o_tty->driver->owner);
 335 err_free_tty:
 336         free_tty_struct(o_tty);
 337         return retval;
 338 }
 339
 340 static int pty_bsd_ioctl(struct tty_struct *tty,
 341                          unsigned int cmd, unsigned long arg)
 342 {
 343         switch (cmd) {
 344         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 345                 return pty_set_lock(tty, (int __user *) arg);
 346         case TIOCSIG:    /* Send signal to other side of pty */
 347                 return pty_signal(tty, (int) arg);
 348         }
 349         return -ENOIOCTLCMD;
 350 }
 351
 352 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
 353 module_param(legacy_count, int, 0);
 354
 355 /*
 356  * The master side of a pty can do TIOCSPTLCK and thus
 357  * has pty_bsd_ioctl.
 358  */
 359 static const struct tty_operations master_pty_ops_bsd = {
 360         .install = pty_install,
 361         .open = pty_open,
 362         .close = pty_close,
 363         .write = pty_write,
 364         .write_room = pty_write_room,
 365         .flush_buffer = pty_flush_buffer,
 366         .chars_in_buffer = pty_chars_in_buffer,
 367         .unthrottle = pty_unthrottle,
 368         .set_termios = pty_set_termios,
 369         .ioctl = pty_bsd_ioctl,
 370         .resize = pty_resize
 371 };
 372
 373 static const struct tty_operations slave_pty_ops_bsd = {
 374         .install = pty_install,
 375         .open = pty_open,
 376         .close = pty_close,
 377         .write = pty_write,
 378         .write_room = pty_write_room,
 379         .flush_buffer = pty_flush_buffer,
 380         .chars_in_buffer = pty_chars_in_buffer,
 381         .unthrottle = pty_unthrottle,
 382         .set_termios = pty_set_termios,
 383         .resize = pty_resize
 384 };
 385
 386 static void __init legacy_pty_init(void)
 387 {
 388         struct tty_driver *pty_driver, *pty_slave_driver;
 389
 390         if (legacy_count <= 0)
 391                 return;
 392
 393         pty_driver = alloc_tty_driver(legacy_count);
 394         if (!pty_driver)
 395                 panic("Couldn't allocate pty driver");
 396
 397         pty_slave_driver = alloc_tty_driver(legacy_count);
 398         if (!pty_slave_driver)
 399                 panic("Couldn't allocate pty slave driver");
 400
 401         pty_driver->driver_name = "pty_master";
 402         pty_driver->name = "pty";
 403         pty_driver->major = PTY_MASTER_MAJOR;
 404         pty_driver->minor_start = 0;
 405         pty_driver->type = TTY_DRIVER_TYPE_PTY;
 406         pty_driver->subtype = PTY_TYPE_MASTER;
 407         pty_driver->init_termios = tty_std_termios;
 408         pty_driver->init_termios.c_iflag = 0;
 409         pty_driver->init_termios.c_oflag = 0;
 410         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 411         pty_driver->init_termios.c_lflag = 0;
 412         pty_driver->init_termios.c_ispeed = 38400;
 413         pty_driver->init_termios.c_ospeed = 38400;
 414         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
 415         pty_driver->other = pty_slave_driver;
 416         tty_set_operations(pty_driver, &master_pty_ops_bsd);
 417
 418         pty_slave_driver->driver_name = "pty_slave";
 419         pty_slave_driver->name = "ttyp";
 420         pty_slave_driver->major = PTY_SLAVE_MAJOR;
 421         pty_slave_driver->minor_start = 0;
 422         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
 423         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
 424         pty_slave_driver->init_termios = tty_std_termios;
 425         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 426         pty_slave_driver->init_termios.c_ispeed = 38400;
 427         pty_slave_driver->init_termios.c_ospeed = 38400;
 428         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
 429                                         TTY_DRIVER_REAL_RAW;
 430         pty_slave_driver->other = pty_driver;
 431         tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
 432
 433         if (tty_register_driver(pty_driver))
 434                 panic("Couldn't register pty driver");
 435         if (tty_register_driver(pty_slave_driver))
 436                 panic("Couldn't register pty slave driver");
 437 }
 438 #else
 439 static inline void legacy_pty_init(void) { }
 440 #endif
 441
 442 /* Unix98 devices */
 443 #ifdef CONFIG_UNIX98_PTYS
 444
 445 static struct cdev ptmx_cdev;
 446
 447 static int pty_unix98_ioctl(struct tty_struct *tty,
 448                             unsigned int cmd, unsigned long arg)
 449 {
 450         switch (cmd) {
 451         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 452                 return pty_set_lock(tty, (int __user *)arg);
 453         case TIOCGPTN: /* Get PT Number */
 454                 return put_user(tty->index, (unsigned int __user *)arg);
 455         case TIOCSIG:    /* Send signal to other side of pty */
 456                 return pty_signal(tty, (int) arg);
 457         }
 458
 459         return -ENOIOCTLCMD;
 460 }
 461
 462 /**
 463  *      ptm_unix98_lookup       -       find a pty master
 464  *      @driver: ptm driver
 465  *      @idx: tty index
 466  *
 467  *      Look up a pty master device. Called under the tty_mutex for now.
 468  *      This provides our locking.
 469  */
 470
 471 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
 472                 struct inode *ptm_inode, int idx)
 473 {
 474         /* Master must be open via /dev/ptmx */
 475         return ERR_PTR(-EIO);
 476 }
 477
 478 /**
 479  *      pts_unix98_lookup       -       find a pty slave
 480  *      @driver: pts driver
 481  *      @idx: tty index
 482  *
 483  *      Look up a pty master device. Called under the tty_mutex for now.
 484  *      This provides our locking for the tty pointer.
 485  */
 486
 487 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
 488                 struct inode *pts_inode, int idx)
 489 {
 490         struct tty_struct *tty;
 491
 492         mutex_lock(&devpts_mutex);
 493         tty = devpts_get_tty(pts_inode, idx);
 494         mutex_unlock(&devpts_mutex);
 495         /* Master must be open before slave */
 496         if (!tty)
 497                 return ERR_PTR(-EIO);
 498         return tty;
 499 }
 500
 501 static void pty_unix98_shutdown(struct tty_struct *tty)
 502 {
 503         tty_driver_remove_tty(tty->driver, tty);
 504         /* We have our own method as we don't use the tty index */
 505         kfree(tty->termios);
 506 }
 507
 508 /* We have no need to install and remove our tty objects as devpts does all
 509    the work for us */
 510
 511 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
 512 {
 513         struct tty_struct *o_tty;
 514         int idx = tty->index;
 515
 516         o_tty = alloc_tty_struct();
 517         if (!o_tty)
 518                 return -ENOMEM;
 519         if (!try_module_get(driver->other->owner)) {
 520                 /* This cannot in fact currently happen */
 521                 goto err_free_tty;
 522         }
 523         initialize_tty_struct(o_tty, driver->other, idx);
 524
 525         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 526         if (tty->termios == NULL)
 527                 goto err_free_mem;
 528         *tty->termios = driver->init_termios;
 529         tty->termios_locked = tty->termios + 1;
 530
 531         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 532         if (o_tty->termios == NULL)
 533                 goto err_free_mem;
 534         *o_tty->termios = driver->other->init_termios;
 535         o_tty->termios_locked = o_tty->termios + 1;
 536
 537         tty_driver_kref_get(driver->other);
 538         if (driver->subtype == PTY_TYPE_MASTER)
 539                 o_tty->count++;
 540         /* Establish the links in both directions */
 541         tty->link   = o_tty;
 542         o_tty->link = tty;
 543         /*
 544          * All structures have been allocated, so now we install them.
 545          * Failures after this point use release_tty to clean up, so
 546          * there's no need to null out the local pointers.
 547          */
 548         tty_driver_kref_get(driver);
 549         tty->count++;
 550         return 0;
 551 err_free_mem:
 552         deinitialize_tty_struct(o_tty);
 553         kfree(o_tty->termios);
 554         kfree(tty->termios);
 555         module_put(o_tty->driver->owner);
 556 err_free_tty:
 557         free_tty_struct(o_tty);
 558         return -ENOMEM;
 559 }
 560
 561 static void ptm_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 562 {
 563 }
 564
 565 static void pts_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 566 {
 567 }
 568
 569 static const struct tty_operations ptm_unix98_ops = {
 570         .lookup = ptm_unix98_lookup,
 571         .install = pty_unix98_install,
 572         .remove = ptm_unix98_remove,
 573         .open = pty_open,
 574         .close = pty_close,
 575         .write = pty_write,
 576         .write_room = pty_write_room,
 577         .flush_buffer = pty_flush_buffer,
 578         .chars_in_buffer = pty_chars_in_buffer,
 579         .unthrottle = pty_unthrottle,
 580         .set_termios = pty_set_termios,
 581         .ioctl = pty_unix98_ioctl,
 582         .shutdown = pty_unix98_shutdown,
 583         .resize = pty_resize
 584 };
 585
 586 static const struct tty_operations pty_unix98_ops = {
 587         .lookup = pts_unix98_lookup,
 588         .install = pty_unix98_install,
 589         .remove = pts_unix98_remove,
 590         .open = pty_open,
 591         .close = pty_close,
 592         .write = pty_write,
 593         .write_room = pty_write_room,
 594         .flush_buffer = pty_flush_buffer,
 595         .chars_in_buffer = pty_chars_in_buffer,
 596         .unthrottle = pty_unthrottle,
 597         .set_termios = pty_set_termios,
 598         .shutdown = pty_unix98_shutdown
 599 };
 600
 601 /**
 602  *      ptmx_open               -       open a unix 98 pty master
 603  *      @inode: inode of device file
 604  *      @filp: file pointer to tty
 605  *
 606  *      Allocate a unix98 pty master device from the ptmx driver.
 607  *
 608  *      Locking: tty_mutex protects the init_dev work. tty->count should
 609  *              protect the rest.
 610  *              allocated_ptys_lock handles the list of free pty numbers
 611  */
 612
 613 static int ptmx_open(struct inode *inode, struct file *filp)
 614 {
 615         struct tty_struct *tty;
 616         int retval;
 617         int index;
 618
 619         nonseekable_open(inode, filp);
 620
 621         retval = tty_alloc_file(filp);
 622         if (retval)
 623                 return retval;
 624
 625         /* find a device that is not in use. */
 626         mutex_lock(&devpts_mutex);
 627         index = devpts_new_index(inode);
 628         if (index < 0) {
 629                 retval = index;
 630                 goto err_file;
 631         }
 632
 633         mutex_unlock(&devpts_mutex);
 634
 635         mutex_lock(&tty_mutex);
 636         mutex_lock(&devpts_mutex);
 637         tty = tty_init_dev(ptm_driver, index);
 638
 639         if (IS_ERR(tty)) {
 640                 retval = PTR_ERR(tty);
 641                 goto out;
 642         }
 643
 644         /* The tty returned here is locked so we can safely
 645            drop the mutex */
 646         mutex_unlock(&devpts_mutex);
 647         mutex_unlock(&tty_mutex);
 648
 649         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
 650
 651         tty_add_file(tty, filp);
 652
 653         retval = devpts_pty_new(inode, tty->link);
 654         if (retval)
 655                 goto err_release;
 656
 657         retval = ptm_driver->ops->open(tty, filp);
 658         if (retval)
 659                 goto err_release;
 660
 661         tty_unlock(tty);
 662         return 0;
 663 err_release:
 664         tty_unlock(tty);
 665         tty_release(inode, filp);
 666         return retval;
 667 out:
 668         mutex_unlock(&tty_mutex);
 669         devpts_kill_index(inode, index);
 670 err_file:
 671         mutex_unlock(&devpts_mutex);
 672         tty_free_file(filp);
 673         return retval;
 674 }
 675
 676 static struct file_operations ptmx_fops;
 677
 678 static void __init unix98_pty_init(void)
 679 {
 680         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
 681         if (!ptm_driver)
 682                 panic("Couldn't allocate Unix98 ptm driver");
 683         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
 684         if (!pts_driver)
 685                 panic("Couldn't allocate Unix98 pts driver");
 686
 687         ptm_driver->driver_name = "pty_master";
 688         ptm_driver->name = "ptm";
 689         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
 690         ptm_driver->minor_start = 0;
 691         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
 692         ptm_driver->subtype = PTY_TYPE_MASTER;
 693         ptm_driver->init_termios = tty_std_termios;
 694         ptm_driver->init_termios.c_iflag = 0;
 695         ptm_driver->init_termios.c_oflag = 0;
 696         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 697         ptm_driver->init_termios.c_lflag = 0;
 698         ptm_driver->init_termios.c_ispeed = 38400;
 699         ptm_driver->init_termios.c_ospeed = 38400;
 700         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 701                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
 702         ptm_driver->other = pts_driver;
 703         tty_set_operations(ptm_driver, &ptm_unix98_ops);
 704
 705         pts_driver->driver_name = "pty_slave";
 706         pts_driver->name = "pts";
 707         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
 708         pts_driver->minor_start = 0;
 709         pts_driver->type = TTY_DRIVER_TYPE_PTY;
 710         pts_driver->subtype = PTY_TYPE_SLAVE;
 711         pts_driver->init_termios = tty_std_termios;
 712         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 713         pts_driver->init_termios.c_ispeed = 38400;
 714         pts_driver->init_termios.c_ospeed = 38400;
 715         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 716                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
 717         pts_driver->other = ptm_driver;
 718         tty_set_operations(pts_driver, &pty_unix98_ops);
 719
 720         if (tty_register_driver(ptm_driver))
 721                 panic("Couldn't register Unix98 ptm driver");
 722         if (tty_register_driver(pts_driver))
 723                 panic("Couldn't register Unix98 pts driver");
 724
 725         /* Now create the /dev/ptmx special device */
 726         tty_default_fops(&ptmx_fops);
 727         ptmx_fops.open = ptmx_open;
 728
 729         cdev_init(&ptmx_cdev, &ptmx_fops);
 730         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
 731             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
 732                 panic("Couldn't register /dev/ptmx driver\n");
 733         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
 734 }
 735
 736 #else
 737 static inline void unix98_pty_init(void) { }
 738 #endif
 739
 740 static int __init pty_init(void)
 741 {
 742         legacy_pty_init();
 743         unix98_pty_init();
 744         return 0;
 745 }
 746 module_init(pty_init);