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 /**
 287  *      pty_common_install              -       set up the pty pair
 288  *      @driver: the pty driver
 289  *      @tty: the tty being instantiated
 290  *      @bool: legacy, true if this is BSD style
 291  *
 292  *      Perform the initial set up for the tty/pty pair. Called from the
 293  *      tty layer when the port is first opened.
 294  *
 295  *      Locking: the caller must hold the tty_mutex
 296  */
 297 static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
 298                 bool legacy)
 299 {
 300         struct tty_struct *o_tty;
 301         struct tty_port *ports[2];
 302         int idx = tty->index;
 303         int retval = -ENOMEM;
 304
 305         o_tty = alloc_tty_struct();
 306         if (!o_tty)
 307                 goto err;
 308         ports[0] = kmalloc(sizeof **ports, GFP_KERNEL);
 309         ports[1] = kmalloc(sizeof **ports, GFP_KERNEL);
 310         if (!ports[0] || !ports[1])
 311                 goto err_free_tty;
 312         if (!try_module_get(driver->other->owner)) {
 313                 /* This cannot in fact currently happen */
 314                 goto err_free_tty;
 315         }
 316         initialize_tty_struct(o_tty, driver->other, idx);
 317
 318         if (legacy) {
 319                 /* We always use new tty termios data so we can do this
 320                    the easy way .. */
 321                 retval = tty_init_termios(tty);
 322                 if (retval)
 323                         goto err_deinit_tty;
 324
 325                 retval = tty_init_termios(o_tty);
 326                 if (retval)
 327                         goto err_free_termios;
 328
 329                 driver->other->ttys[idx] = o_tty;
 330                 driver->ttys[idx] = tty;
 331         } else {
 332                 memset(&tty->termios_locked, 0, sizeof(tty->termios_locked));
 333                 tty->termios = driver->init_termios;
 334                 memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked));
 335                 o_tty->termios = driver->other->init_termios;
 336         }
 337
 338         /*
 339          * Everything allocated ... set up the o_tty structure.
 340          */
 341         tty_driver_kref_get(driver->other);
 342         if (driver->subtype == PTY_TYPE_MASTER)
 343                 o_tty->count++;
 344         /* Establish the links in both directions */
 345         tty->link   = o_tty;
 346         o_tty->link = tty;
 347         tty_port_init(ports[0]);
 348         tty_port_init(ports[1]);
 349         o_tty->port = ports[0];
 350         tty->port = ports[1];
 351
 352         tty_driver_kref_get(driver);
 353         tty->count++;
 354         return 0;
 355 err_free_termios:
 356         if (legacy)
 357                 tty_free_termios(tty);
 358 err_deinit_tty:
 359         deinitialize_tty_struct(o_tty);
 360         module_put(o_tty->driver->owner);
 361 err_free_tty:
 362         kfree(ports[0]);
 363         kfree(ports[1]);
 364         free_tty_struct(o_tty);
 365 err:
 366         return retval;
 367 }
 368
 369 static void pty_cleanup(struct tty_struct *tty)
 370 {
 371         kfree(tty->port);
 372 }
 373
 374 /* Traditional BSD devices */
 375 #ifdef CONFIG_LEGACY_PTYS
 376
 377 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
 378 {
 379         return pty_common_install(driver, tty, true);
 380 }
 381
 382 static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
 383 {
 384         struct tty_struct *pair = tty->link;
 385         driver->ttys[tty->index] = NULL;
 386         if (pair)
 387                 pair->driver->ttys[pair->index] = NULL;
 388 }
 389
 390 static int pty_bsd_ioctl(struct tty_struct *tty,
 391                          unsigned int cmd, unsigned long arg)
 392 {
 393         switch (cmd) {
 394         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 395                 return pty_set_lock(tty, (int __user *) arg);
 396         case TIOCSIG:    /* Send signal to other side of pty */
 397                 return pty_signal(tty, (int) arg);
 398         }
 399         return -ENOIOCTLCMD;
 400 }
 401
 402 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
 403 module_param(legacy_count, int, 0);
 404
 405 /*
 406  * The master side of a pty can do TIOCSPTLCK and thus
 407  * has pty_bsd_ioctl.
 408  */
 409 static const struct tty_operations master_pty_ops_bsd = {
 410         .install = pty_install,
 411         .open = pty_open,
 412         .close = pty_close,
 413         .write = pty_write,
 414         .write_room = pty_write_room,
 415         .flush_buffer = pty_flush_buffer,
 416         .chars_in_buffer = pty_chars_in_buffer,
 417         .unthrottle = pty_unthrottle,
 418         .set_termios = pty_set_termios,
 419         .ioctl = pty_bsd_ioctl,
 420         .cleanup = pty_cleanup,
 421         .resize = pty_resize,
 422         .remove = pty_remove
 423 };
 424
 425 static const struct tty_operations slave_pty_ops_bsd = {
 426         .install = pty_install,
 427         .open = pty_open,
 428         .close = pty_close,
 429         .write = pty_write,
 430         .write_room = pty_write_room,
 431         .flush_buffer = pty_flush_buffer,
 432         .chars_in_buffer = pty_chars_in_buffer,
 433         .unthrottle = pty_unthrottle,
 434         .set_termios = pty_set_termios,
 435         .cleanup = pty_cleanup,
 436         .resize = pty_resize,
 437         .remove = pty_remove
 438 };
 439
 440 static void __init legacy_pty_init(void)
 441 {
 442         struct tty_driver *pty_driver, *pty_slave_driver;
 443
 444         if (legacy_count <= 0)
 445                 return;
 446
 447         pty_driver = tty_alloc_driver(legacy_count,
 448                         TTY_DRIVER_RESET_TERMIOS |
 449                         TTY_DRIVER_REAL_RAW |
 450                         TTY_DRIVER_DYNAMIC_ALLOC);
 451         if (IS_ERR(pty_driver))
 452                 panic("Couldn't allocate pty driver");
 453
 454         pty_slave_driver = tty_alloc_driver(legacy_count,
 455                         TTY_DRIVER_RESET_TERMIOS |
 456                         TTY_DRIVER_REAL_RAW |
 457                         TTY_DRIVER_DYNAMIC_ALLOC);
 458         if (IS_ERR(pty_slave_driver))
 459                 panic("Couldn't allocate pty slave driver");
 460
 461         pty_driver->driver_name = "pty_master";
 462         pty_driver->name = "pty";
 463         pty_driver->major = PTY_MASTER_MAJOR;
 464         pty_driver->minor_start = 0;
 465         pty_driver->type = TTY_DRIVER_TYPE_PTY;
 466         pty_driver->subtype = PTY_TYPE_MASTER;
 467         pty_driver->init_termios = tty_std_termios;
 468         pty_driver->init_termios.c_iflag = 0;
 469         pty_driver->init_termios.c_oflag = 0;
 470         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 471         pty_driver->init_termios.c_lflag = 0;
 472         pty_driver->init_termios.c_ispeed = 38400;
 473         pty_driver->init_termios.c_ospeed = 38400;
 474         pty_driver->other = pty_slave_driver;
 475         tty_set_operations(pty_driver, &master_pty_ops_bsd);
 476
 477         pty_slave_driver->driver_name = "pty_slave";
 478         pty_slave_driver->name = "ttyp";
 479         pty_slave_driver->major = PTY_SLAVE_MAJOR;
 480         pty_slave_driver->minor_start = 0;
 481         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
 482         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
 483         pty_slave_driver->init_termios = tty_std_termios;
 484         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 485         pty_slave_driver->init_termios.c_ispeed = 38400;
 486         pty_slave_driver->init_termios.c_ospeed = 38400;
 487         pty_slave_driver->other = pty_driver;
 488         tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
 489
 490         if (tty_register_driver(pty_driver))
 491                 panic("Couldn't register pty driver");
 492         if (tty_register_driver(pty_slave_driver))
 493                 panic("Couldn't register pty slave driver");
 494 }
 495 #else
 496 static inline void legacy_pty_init(void) { }
 497 #endif
 498
 499 /* Unix98 devices */
 500 #ifdef CONFIG_UNIX98_PTYS
 501
 502 static struct cdev ptmx_cdev;
 503
 504 static int pty_unix98_ioctl(struct tty_struct *tty,
 505                             unsigned int cmd, unsigned long arg)
 506 {
 507         switch (cmd) {
 508         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 509                 return pty_set_lock(tty, (int __user *)arg);
 510         case TIOCGPTN: /* Get PT Number */
 511                 return put_user(tty->index, (unsigned int __user *)arg);
 512         case TIOCSIG:    /* Send signal to other side of pty */
 513                 return pty_signal(tty, (int) arg);
 514         }
 515
 516         return -ENOIOCTLCMD;
 517 }
 518
 519 /**
 520  *      ptm_unix98_lookup       -       find a pty master
 521  *      @driver: ptm driver
 522  *      @idx: tty index
 523  *
 524  *      Look up a pty master device. Called under the tty_mutex for now.
 525  *      This provides our locking.
 526  */
 527
 528 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
 529                 struct inode *ptm_inode, int idx)
 530 {
 531         /* Master must be open via /dev/ptmx */
 532         return ERR_PTR(-EIO);
 533 }
 534
 535 /**
 536  *      pts_unix98_lookup       -       find a pty slave
 537  *      @driver: pts driver
 538  *      @idx: tty index
 539  *
 540  *      Look up a pty master device. Called under the tty_mutex for now.
 541  *      This provides our locking for the tty pointer.
 542  */
 543
 544 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
 545                 struct inode *pts_inode, int idx)
 546 {
 547         struct tty_struct *tty;
 548
 549         mutex_lock(&devpts_mutex);
 550         tty = devpts_get_tty(pts_inode, idx);
 551         mutex_unlock(&devpts_mutex);
 552         /* Master must be open before slave */
 553         if (!tty)
 554                 return ERR_PTR(-EIO);
 555         return tty;
 556 }
 557
 558 /* We have no need to install and remove our tty objects as devpts does all
 559    the work for us */
 560
 561 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
 562 {
 563         return pty_common_install(driver, tty, false);
 564 }
 565
 566 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 567 {
 568 }
 569
 570 static const struct tty_operations ptm_unix98_ops = {
 571         .lookup = ptm_unix98_lookup,
 572         .install = pty_unix98_install,
 573         .remove = pty_unix98_remove,
 574         .open = pty_open,
 575         .close = pty_close,
 576         .write = pty_write,
 577         .write_room = pty_write_room,
 578         .flush_buffer = pty_flush_buffer,
 579         .chars_in_buffer = pty_chars_in_buffer,
 580         .unthrottle = pty_unthrottle,
 581         .set_termios = pty_set_termios,
 582         .ioctl = pty_unix98_ioctl,
 583         .resize = pty_resize,
 584         .cleanup = pty_cleanup
 585 };
 586
 587 static const struct tty_operations pty_unix98_ops = {
 588         .lookup = pts_unix98_lookup,
 589         .install = pty_unix98_install,
 590         .remove = pty_unix98_remove,
 591         .open = pty_open,
 592         .close = pty_close,
 593         .write = pty_write,
 594         .write_room = pty_write_room,
 595         .flush_buffer = pty_flush_buffer,
 596         .chars_in_buffer = pty_chars_in_buffer,
 597         .unthrottle = pty_unthrottle,
 598         .set_termios = pty_set_termios,
 599         .cleanup = pty_cleanup,
 600 };
 601
 602 /**
 603  *      ptmx_open               -       open a unix 98 pty master
 604  *      @inode: inode of device file
 605  *      @filp: file pointer to tty
 606  *
 607  *      Allocate a unix98 pty master device from the ptmx driver.
 608  *
 609  *      Locking: tty_mutex protects the init_dev work. tty->count should
 610  *              protect the rest.
 611  *              allocated_ptys_lock handles the list of free pty numbers
 612  */
 613
 614 static int ptmx_open(struct inode *inode, struct file *filp)
 615 {
 616         struct tty_struct *tty;
 617         int retval;
 618         int index;
 619
 620         nonseekable_open(inode, filp);
 621
 622         retval = tty_alloc_file(filp);
 623         if (retval)
 624                 return retval;
 625
 626         /* find a device that is not in use. */
 627         mutex_lock(&devpts_mutex);
 628         index = devpts_new_index(inode);
 629         if (index < 0) {
 630                 retval = index;
 631                 mutex_unlock(&devpts_mutex);
 632                 goto err_file;
 633         }
 634
 635         mutex_unlock(&devpts_mutex);
 636
 637         mutex_lock(&tty_mutex);
 638         tty = tty_init_dev(ptm_driver, index);
 639
 640         if (IS_ERR(tty)) {
 641                 retval = PTR_ERR(tty);
 642                 goto out;
 643         }
 644
 645         /* The tty returned here is locked so we can safely
 646            drop the 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         tty_free_file(filp);
 672         return retval;
 673 }
 674
 675 static struct file_operations ptmx_fops;
 676
 677 static void __init unix98_pty_init(void)
 678 {
 679         ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
 680                         TTY_DRIVER_RESET_TERMIOS |
 681                         TTY_DRIVER_REAL_RAW |
 682                         TTY_DRIVER_DYNAMIC_DEV |
 683                         TTY_DRIVER_DEVPTS_MEM |
 684                         TTY_DRIVER_DYNAMIC_ALLOC);
 685         if (IS_ERR(ptm_driver))
 686                 panic("Couldn't allocate Unix98 ptm driver");
 687         pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
 688                         TTY_DRIVER_RESET_TERMIOS |
 689                         TTY_DRIVER_REAL_RAW |
 690                         TTY_DRIVER_DYNAMIC_DEV |
 691                         TTY_DRIVER_DEVPTS_MEM |
 692                         TTY_DRIVER_DYNAMIC_ALLOC);
 693         if (IS_ERR(pts_driver))
 694                 panic("Couldn't allocate Unix98 pts driver");
 695
 696         ptm_driver->driver_name = "pty_master";
 697         ptm_driver->name = "ptm";
 698         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
 699         ptm_driver->minor_start = 0;
 700         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
 701         ptm_driver->subtype = PTY_TYPE_MASTER;
 702         ptm_driver->init_termios = tty_std_termios;
 703         ptm_driver->init_termios.c_iflag = 0;
 704         ptm_driver->init_termios.c_oflag = 0;
 705         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 706         ptm_driver->init_termios.c_lflag = 0;
 707         ptm_driver->init_termios.c_ispeed = 38400;
 708         ptm_driver->init_termios.c_ospeed = 38400;
 709         ptm_driver->other = pts_driver;
 710         tty_set_operations(ptm_driver, &ptm_unix98_ops);
 711
 712         pts_driver->driver_name = "pty_slave";
 713         pts_driver->name = "pts";
 714         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
 715         pts_driver->minor_start = 0;
 716         pts_driver->type = TTY_DRIVER_TYPE_PTY;
 717         pts_driver->subtype = PTY_TYPE_SLAVE;
 718         pts_driver->init_termios = tty_std_termios;
 719         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 720         pts_driver->init_termios.c_ispeed = 38400;
 721         pts_driver->init_termios.c_ospeed = 38400;
 722         pts_driver->other = ptm_driver;
 723         tty_set_operations(pts_driver, &pty_unix98_ops);
 724
 725         if (tty_register_driver(ptm_driver))
 726                 panic("Couldn't register Unix98 ptm driver");
 727         if (tty_register_driver(pts_driver))
 728                 panic("Couldn't register Unix98 pts driver");
 729
 730         /* Now create the /dev/ptmx special device */
 731         tty_default_fops(&ptmx_fops);
 732         ptmx_fops.open = ptmx_open;
 733
 734         cdev_init(&ptmx_cdev, &ptmx_fops);
 735         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
 736             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
 737                 panic("Couldn't register /dev/ptmx driver\n");
 738         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
 739 }
 740
 741 #else
 742 static inline void unix98_pty_init(void) { }
 743 #endif
 744
 745 static int __init pty_init(void)
 746 {
 747         legacy_pty_init();
 748         unix98_pty_init();
 749         return 0;
 750 }
 751 module_init(pty_init);