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  */
   8
   9 #include <linux/module.h>
  10
  11 #include <linux/errno.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/tty.h>
  14 #include <linux/tty_flip.h>
  15 #include <linux/fcntl.h>
  16 #include <linux/sched.h>
  17 #include <linux/string.h>
  18 #include <linux/major.h>
  19 #include <linux/mm.h>
  20 #include <linux/init.h>
  21 #include <linux/device.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/bitops.h>
  24 #include <linux/devpts_fs.h>
  25 #include <linux/slab.h>
  26 #include <linux/mutex.h>
  27
  28
  29 #ifdef CONFIG_UNIX98_PTYS
  30 static struct tty_driver *ptm_driver;
  31 static struct tty_driver *pts_driver;
  32 static DEFINE_MUTEX(devpts_mutex);
  33 #endif
  34
  35 static void pty_close(struct tty_struct *tty, struct file *filp)
  36 {
  37         BUG_ON(!tty);
  38         if (tty->driver->subtype == PTY_TYPE_MASTER)
  39                 WARN_ON(tty->count > 1);
  40         else {
  41                 if (test_bit(TTY_IO_ERROR, &tty->flags))
  42                         return;
  43                 if (tty->count > 2)
  44                         return;
  45         }
  46         set_bit(TTY_IO_ERROR, &tty->flags);
  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         set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
  54         wake_up_interruptible(&tty->link->read_wait);
  55         wake_up_interruptible(&tty->link->write_wait);
  56         if (tty->driver->subtype == PTY_TYPE_MASTER) {
  57                 set_bit(TTY_OTHER_CLOSED, &tty->flags);
  58 #ifdef CONFIG_UNIX98_PTYS
  59                 if (tty->driver == ptm_driver) {
  60                         mutex_lock(&devpts_mutex);
  61                         if (tty->link->driver_data)
  62                                 devpts_pty_kill(tty->link->driver_data);
  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  *      Limit the buffer space used by ptys to 8k.
  93  */
  94
  95 static int pty_space(struct tty_struct *to)
  96 {
  97         int n = tty_buffer_space_avail(to->port);
  98         return min(n, 8192);
  99 }
 100
 101 /**
 102  *      pty_write               -       write to a pty
 103  *      @tty: the tty we write from
 104  *      @buf: kernel buffer of data
 105  *      @count: bytes to write
 106  *
 107  *      Our "hardware" write method. Data is coming from the ldisc which
 108  *      may be in a non sleeping state. We simply throw this at the other
 109  *      end of the link as if we were an IRQ handler receiving stuff for
 110  *      the other side of the pty/tty pair.
 111  */
 112
 113 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
 114 {
 115         struct tty_struct *to = tty->link;
 116
 117         if (tty->stopped)
 118                 return 0;
 119
 120         if (c > 0) {
 121                 /* Stuff the data into the input queue of the other end */
 122                 c = tty_insert_flip_string(to->port, buf, c);
 123                 /* And shovel */
 124                 if (c)
 125                         tty_flip_buffer_push(to->port);
 126         }
 127         return c;
 128 }
 129
 130 /**
 131  *      pty_write_room  -       write space
 132  *      @tty: tty we are writing from
 133  *
 134  *      Report how many bytes the ldisc can send into the queue for
 135  *      the other device.
 136  */
 137
 138 static int pty_write_room(struct tty_struct *tty)
 139 {
 140         if (tty->stopped)
 141                 return 0;
 142         return pty_space(tty->link);
 143 }
 144
 145 /**
 146  *      pty_chars_in_buffer     -       characters currently in our tx queue
 147  *      @tty: our tty
 148  *
 149  *      Report how much we have in the transmit queue. As everything is
 150  *      instantly at the other end this is easy to implement.
 151  */
 152
 153 static int pty_chars_in_buffer(struct tty_struct *tty)
 154 {
 155         return 0;
 156 }
 157
 158 /* Set the lock flag on a pty */
 159 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
 160 {
 161         int val;
 162         if (get_user(val, arg))
 163                 return -EFAULT;
 164         if (val)
 165                 set_bit(TTY_PTY_LOCK, &tty->flags);
 166         else
 167                 clear_bit(TTY_PTY_LOCK, &tty->flags);
 168         return 0;
 169 }
 170
 171 static int pty_get_lock(struct tty_struct *tty, int __user *arg)
 172 {
 173         int locked = test_bit(TTY_PTY_LOCK, &tty->flags);
 174         return put_user(locked, arg);
 175 }
 176
 177 /* Set the packet mode on a pty */
 178 static int pty_set_pktmode(struct tty_struct *tty, int __user *arg)
 179 {
 180         unsigned long flags;
 181         int pktmode;
 182
 183         if (get_user(pktmode, arg))
 184                 return -EFAULT;
 185
 186         spin_lock_irqsave(&tty->ctrl_lock, flags);
 187         if (pktmode) {
 188                 if (!tty->packet) {
 189                         tty->packet = 1;
 190                         tty->link->ctrl_status = 0;
 191                 }
 192         } else
 193                 tty->packet = 0;
 194         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 195
 196         return 0;
 197 }
 198
 199 /* Get the packet mode of a pty */
 200 static int pty_get_pktmode(struct tty_struct *tty, int __user *arg)
 201 {
 202         int pktmode = tty->packet;
 203         return put_user(pktmode, arg);
 204 }
 205
 206 /* Send a signal to the slave */
 207 static int pty_signal(struct tty_struct *tty, int sig)
 208 {
 209         unsigned long flags;
 210         struct pid *pgrp;
 211
 212         if (tty->link) {
 213                 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
 214                 pgrp = get_pid(tty->link->pgrp);
 215                 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
 216
 217                 kill_pgrp(pgrp, sig, 1);
 218                 put_pid(pgrp);
 219         }
 220         return 0;
 221 }
 222
 223 static void pty_flush_buffer(struct tty_struct *tty)
 224 {
 225         struct tty_struct *to = tty->link;
 226         unsigned long flags;
 227
 228         if (!to)
 229                 return;
 230         /* tty_buffer_flush(to); FIXME */
 231         if (to->packet) {
 232                 spin_lock_irqsave(&tty->ctrl_lock, flags);
 233                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
 234                 wake_up_interruptible(&to->read_wait);
 235                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 236         }
 237 }
 238
 239 static int pty_open(struct tty_struct *tty, struct file *filp)
 240 {
 241         if (!tty || !tty->link)
 242                 return -ENODEV;
 243
 244         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
 245                 goto out;
 246         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
 247                 goto out;
 248         if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1)
 249                 goto out;
 250
 251         clear_bit(TTY_IO_ERROR, &tty->flags);
 252         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
 253         set_bit(TTY_THROTTLED, &tty->flags);
 254         return 0;
 255
 256 out:
 257         set_bit(TTY_IO_ERROR, &tty->flags);
 258         return -EIO;
 259 }
 260
 261 static void pty_set_termios(struct tty_struct *tty,
 262                                         struct ktermios *old_termios)
 263 {
 264         tty->termios.c_cflag &= ~(CSIZE | PARENB);
 265         tty->termios.c_cflag |= (CS8 | CREAD);
 266 }
 267
 268 /**
 269  *      pty_do_resize           -       resize event
 270  *      @tty: tty being resized
 271  *      @ws: window size being set.
 272  *
 273  *      Update the termios variables and send the necessary signals to
 274  *      peform a terminal resize correctly
 275  */
 276
 277 static int pty_resize(struct tty_struct *tty,  struct winsize *ws)
 278 {
 279         struct pid *pgrp, *rpgrp;
 280         unsigned long flags;
 281         struct tty_struct *pty = tty->link;
 282
 283         /* For a PTY we need to lock the tty side */
 284         mutex_lock(&tty->winsize_mutex);
 285         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
 286                 goto done;
 287
 288         /* Get the PID values and reference them so we can
 289            avoid holding the tty ctrl lock while sending signals.
 290            We need to lock these individually however. */
 291
 292         spin_lock_irqsave(&tty->ctrl_lock, flags);
 293         pgrp = get_pid(tty->pgrp);
 294         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 295
 296         spin_lock_irqsave(&pty->ctrl_lock, flags);
 297         rpgrp = get_pid(pty->pgrp);
 298         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
 299
 300         if (pgrp)
 301                 kill_pgrp(pgrp, SIGWINCH, 1);
 302         if (rpgrp != pgrp && rpgrp)
 303                 kill_pgrp(rpgrp, SIGWINCH, 1);
 304
 305         put_pid(pgrp);
 306         put_pid(rpgrp);
 307
 308         tty->winsize = *ws;
 309         pty->winsize = *ws;     /* Never used so will go away soon */
 310 done:
 311         mutex_unlock(&tty->winsize_mutex);
 312         return 0;
 313 }
 314
 315 /**
 316  *      pty_common_install              -       set up the pty pair
 317  *      @driver: the pty driver
 318  *      @tty: the tty being instantiated
 319  *      @legacy: true if this is BSD style
 320  *
 321  *      Perform the initial set up for the tty/pty pair. Called from the
 322  *      tty layer when the port is first opened.
 323  *
 324  *      Locking: the caller must hold the tty_mutex
 325  */
 326 static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
 327                 bool legacy)
 328 {
 329         struct tty_struct *o_tty;
 330         struct tty_port *ports[2];
 331         int idx = tty->index;
 332         int retval = -ENOMEM;
 333
 334         ports[0] = kmalloc(sizeof **ports, GFP_KERNEL);
 335         ports[1] = kmalloc(sizeof **ports, GFP_KERNEL);
 336         if (!ports[0] || !ports[1])
 337                 goto err;
 338         if (!try_module_get(driver->other->owner)) {
 339                 /* This cannot in fact currently happen */
 340                 goto err;
 341         }
 342         o_tty = alloc_tty_struct(driver->other, idx);
 343         if (!o_tty)
 344                 goto err_put_module;
 345
 346         if (legacy) {
 347                 /* We always use new tty termios data so we can do this
 348                    the easy way .. */
 349                 retval = tty_init_termios(tty);
 350                 if (retval)
 351                         goto err_deinit_tty;
 352
 353                 retval = tty_init_termios(o_tty);
 354                 if (retval)
 355                         goto err_free_termios;
 356
 357                 driver->other->ttys[idx] = o_tty;
 358                 driver->ttys[idx] = tty;
 359         } else {
 360                 memset(&tty->termios_locked, 0, sizeof(tty->termios_locked));
 361                 tty->termios = driver->init_termios;
 362                 memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked));
 363                 o_tty->termios = driver->other->init_termios;
 364         }
 365
 366         /*
 367          * Everything allocated ... set up the o_tty structure.
 368          */
 369         tty_driver_kref_get(driver->other);
 370         if (driver->subtype == PTY_TYPE_MASTER)
 371                 o_tty->count++;
 372         /* Establish the links in both directions */
 373         tty->link   = o_tty;
 374         o_tty->link = tty;
 375         tty_port_init(ports[0]);
 376         tty_port_init(ports[1]);
 377         o_tty->port = ports[0];
 378         tty->port = ports[1];
 379         o_tty->port->itty = o_tty;
 380
 381         tty_driver_kref_get(driver);
 382         tty->count++;
 383         return 0;
 384 err_free_termios:
 385         if (legacy)
 386                 tty_free_termios(tty);
 387 err_deinit_tty:
 388         deinitialize_tty_struct(o_tty);
 389         free_tty_struct(o_tty);
 390 err_put_module:
 391         module_put(driver->other->owner);
 392 err:
 393         kfree(ports[0]);
 394         kfree(ports[1]);
 395         return retval;
 396 }
 397
 398 static void pty_cleanup(struct tty_struct *tty)
 399 {
 400         tty_port_put(tty->port);
 401 }
 402
 403 /* Traditional BSD devices */
 404 #ifdef CONFIG_LEGACY_PTYS
 405
 406 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
 407 {
 408         return pty_common_install(driver, tty, true);
 409 }
 410
 411 static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
 412 {
 413         struct tty_struct *pair = tty->link;
 414         driver->ttys[tty->index] = NULL;
 415         if (pair)
 416                 pair->driver->ttys[pair->index] = NULL;
 417 }
 418
 419 static int pty_bsd_ioctl(struct tty_struct *tty,
 420                          unsigned int cmd, unsigned long arg)
 421 {
 422         switch (cmd) {
 423         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 424                 return pty_set_lock(tty, (int __user *) arg);
 425         case TIOCGPTLCK: /* Get PT Lock status */
 426                 return pty_get_lock(tty, (int __user *)arg);
 427         case TIOCPKT: /* Set PT packet mode */
 428                 return pty_set_pktmode(tty, (int __user *)arg);
 429         case TIOCGPKT: /* Get PT packet mode */
 430                 return pty_get_pktmode(tty, (int __user *)arg);
 431         case TIOCSIG:    /* Send signal to other side of pty */
 432                 return pty_signal(tty, (int) arg);
 433         case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */
 434                 return -EINVAL;
 435         }
 436         return -ENOIOCTLCMD;
 437 }
 438
 439 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
 440 module_param(legacy_count, int, 0);
 441
 442 /*
 443  * The master side of a pty can do TIOCSPTLCK and thus
 444  * has pty_bsd_ioctl.
 445  */
 446 static const struct tty_operations master_pty_ops_bsd = {
 447         .install = pty_install,
 448         .open = pty_open,
 449         .close = pty_close,
 450         .write = pty_write,
 451         .write_room = pty_write_room,
 452         .flush_buffer = pty_flush_buffer,
 453         .chars_in_buffer = pty_chars_in_buffer,
 454         .unthrottle = pty_unthrottle,
 455         .set_termios = pty_set_termios,
 456         .ioctl = pty_bsd_ioctl,
 457         .cleanup = pty_cleanup,
 458         .resize = pty_resize,
 459         .remove = pty_remove
 460 };
 461
 462 static const struct tty_operations slave_pty_ops_bsd = {
 463         .install = pty_install,
 464         .open = pty_open,
 465         .close = pty_close,
 466         .write = pty_write,
 467         .write_room = pty_write_room,
 468         .flush_buffer = pty_flush_buffer,
 469         .chars_in_buffer = pty_chars_in_buffer,
 470         .unthrottle = pty_unthrottle,
 471         .set_termios = pty_set_termios,
 472         .cleanup = pty_cleanup,
 473         .resize = pty_resize,
 474         .remove = pty_remove
 475 };
 476
 477 static void __init legacy_pty_init(void)
 478 {
 479         struct tty_driver *pty_driver, *pty_slave_driver;
 480
 481         if (legacy_count <= 0)
 482                 return;
 483
 484         pty_driver = tty_alloc_driver(legacy_count,
 485                         TTY_DRIVER_RESET_TERMIOS |
 486                         TTY_DRIVER_REAL_RAW |
 487                         TTY_DRIVER_DYNAMIC_ALLOC);
 488         if (IS_ERR(pty_driver))
 489                 panic("Couldn't allocate pty driver");
 490
 491         pty_slave_driver = tty_alloc_driver(legacy_count,
 492                         TTY_DRIVER_RESET_TERMIOS |
 493                         TTY_DRIVER_REAL_RAW |
 494                         TTY_DRIVER_DYNAMIC_ALLOC);
 495         if (IS_ERR(pty_slave_driver))
 496                 panic("Couldn't allocate pty slave driver");
 497
 498         pty_driver->driver_name = "pty_master";
 499         pty_driver->name = "pty";
 500         pty_driver->major = PTY_MASTER_MAJOR;
 501         pty_driver->minor_start = 0;
 502         pty_driver->type = TTY_DRIVER_TYPE_PTY;
 503         pty_driver->subtype = PTY_TYPE_MASTER;
 504         pty_driver->init_termios = tty_std_termios;
 505         pty_driver->init_termios.c_iflag = 0;
 506         pty_driver->init_termios.c_oflag = 0;
 507         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 508         pty_driver->init_termios.c_lflag = 0;
 509         pty_driver->init_termios.c_ispeed = 38400;
 510         pty_driver->init_termios.c_ospeed = 38400;
 511         pty_driver->other = pty_slave_driver;
 512         tty_set_operations(pty_driver, &master_pty_ops_bsd);
 513
 514         pty_slave_driver->driver_name = "pty_slave";
 515         pty_slave_driver->name = "ttyp";
 516         pty_slave_driver->major = PTY_SLAVE_MAJOR;
 517         pty_slave_driver->minor_start = 0;
 518         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
 519         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
 520         pty_slave_driver->init_termios = tty_std_termios;
 521         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 522         pty_slave_driver->init_termios.c_ispeed = 38400;
 523         pty_slave_driver->init_termios.c_ospeed = 38400;
 524         pty_slave_driver->other = pty_driver;
 525         tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
 526
 527         if (tty_register_driver(pty_driver))
 528                 panic("Couldn't register pty driver");
 529         if (tty_register_driver(pty_slave_driver))
 530                 panic("Couldn't register pty slave driver");
 531 }
 532 #else
 533 static inline void legacy_pty_init(void) { }
 534 #endif
 535
 536 /* Unix98 devices */
 537 #ifdef CONFIG_UNIX98_PTYS
 538
 539 static struct cdev ptmx_cdev;
 540
 541 static int pty_unix98_ioctl(struct tty_struct *tty,
 542                             unsigned int cmd, unsigned long arg)
 543 {
 544         switch (cmd) {
 545         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 546                 return pty_set_lock(tty, (int __user *)arg);
 547         case TIOCGPTLCK: /* Get PT Lock status */
 548                 return pty_get_lock(tty, (int __user *)arg);
 549         case TIOCPKT: /* Set PT packet mode */
 550                 return pty_set_pktmode(tty, (int __user *)arg);
 551         case TIOCGPKT: /* Get PT packet mode */
 552                 return pty_get_pktmode(tty, (int __user *)arg);
 553         case TIOCGPTN: /* Get PT Number */
 554                 return put_user(tty->index, (unsigned int __user *)arg);
 555         case TIOCSIG:    /* Send signal to other side of pty */
 556                 return pty_signal(tty, (int) arg);
 557         }
 558
 559         return -ENOIOCTLCMD;
 560 }
 561
 562 /**
 563  *      ptm_unix98_lookup       -       find a pty master
 564  *      @driver: ptm driver
 565  *      @idx: tty index
 566  *
 567  *      Look up a pty master device. Called under the tty_mutex for now.
 568  *      This provides our locking.
 569  */
 570
 571 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
 572                 struct inode *ptm_inode, int idx)
 573 {
 574         /* Master must be open via /dev/ptmx */
 575         return ERR_PTR(-EIO);
 576 }
 577
 578 /**
 579  *      pts_unix98_lookup       -       find a pty slave
 580  *      @driver: pts driver
 581  *      @idx: tty index
 582  *
 583  *      Look up a pty master device. Called under the tty_mutex for now.
 584  *      This provides our locking for the tty pointer.
 585  */
 586
 587 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
 588                 struct inode *pts_inode, int idx)
 589 {
 590         struct tty_struct *tty;
 591
 592         mutex_lock(&devpts_mutex);
 593         tty = devpts_get_priv(pts_inode);
 594         mutex_unlock(&devpts_mutex);
 595         /* Master must be open before slave */
 596         if (!tty)
 597                 return ERR_PTR(-EIO);
 598         return tty;
 599 }
 600
 601 /* We have no need to install and remove our tty objects as devpts does all
 602    the work for us */
 603
 604 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
 605 {
 606         return pty_common_install(driver, tty, false);
 607 }
 608
 609 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 610 {
 611 }
 612
 613 /* this is called once with whichever end is closed last */
 614 static void pty_unix98_shutdown(struct tty_struct *tty)
 615 {
 616         devpts_kill_index(tty->driver_data, tty->index);
 617 }
 618
 619 static const struct tty_operations ptm_unix98_ops = {
 620         .lookup = ptm_unix98_lookup,
 621         .install = pty_unix98_install,
 622         .remove = pty_unix98_remove,
 623         .open = pty_open,
 624         .close = pty_close,
 625         .write = pty_write,
 626         .write_room = pty_write_room,
 627         .flush_buffer = pty_flush_buffer,
 628         .chars_in_buffer = pty_chars_in_buffer,
 629         .unthrottle = pty_unthrottle,
 630         .set_termios = pty_set_termios,
 631         .ioctl = pty_unix98_ioctl,
 632         .resize = pty_resize,
 633         .shutdown = pty_unix98_shutdown,
 634         .cleanup = pty_cleanup
 635 };
 636
 637 static const struct tty_operations pty_unix98_ops = {
 638         .lookup = pts_unix98_lookup,
 639         .install = pty_unix98_install,
 640         .remove = pty_unix98_remove,
 641         .open = pty_open,
 642         .close = pty_close,
 643         .write = pty_write,
 644         .write_room = pty_write_room,
 645         .flush_buffer = pty_flush_buffer,
 646         .chars_in_buffer = pty_chars_in_buffer,
 647         .unthrottle = pty_unthrottle,
 648         .set_termios = pty_set_termios,
 649         .shutdown = pty_unix98_shutdown,
 650         .cleanup = pty_cleanup,
 651 };
 652
 653 /**
 654  *      ptmx_open               -       open a unix 98 pty master
 655  *      @inode: inode of device file
 656  *      @filp: file pointer to tty
 657  *
 658  *      Allocate a unix98 pty master device from the ptmx driver.
 659  *
 660  *      Locking: tty_mutex protects the init_dev work. tty->count should
 661  *              protect the rest.
 662  *              allocated_ptys_lock handles the list of free pty numbers
 663  */
 664
 665 static int ptmx_open(struct inode *inode, struct file *filp)
 666 {
 667         struct tty_struct *tty;
 668         struct inode *slave_inode;
 669         int retval;
 670         int index;
 671
 672         nonseekable_open(inode, filp);
 673
 674         /* We refuse fsnotify events on ptmx, since it's a shared resource */
 675         filp->f_mode |= FMODE_NONOTIFY;
 676
 677         retval = tty_alloc_file(filp);
 678         if (retval)
 679                 return retval;
 680
 681         /* find a device that is not in use. */
 682         mutex_lock(&devpts_mutex);
 683         index = devpts_new_index(inode);
 684         if (index < 0) {
 685                 retval = index;
 686                 mutex_unlock(&devpts_mutex);
 687                 goto err_file;
 688         }
 689
 690         mutex_unlock(&devpts_mutex);
 691
 692         mutex_lock(&tty_mutex);
 693         tty = tty_init_dev(ptm_driver, index);
 694
 695         if (IS_ERR(tty)) {
 696                 retval = PTR_ERR(tty);
 697                 goto out;
 698         }
 699
 700         /* The tty returned here is locked so we can safely
 701            drop the mutex */
 702         mutex_unlock(&tty_mutex);
 703
 704         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
 705         tty->driver_data = inode;
 706
 707         tty_add_file(tty, filp);
 708
 709         slave_inode = devpts_pty_new(inode,
 710                         MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index,
 711                         tty->link);
 712         if (IS_ERR(slave_inode)) {
 713                 retval = PTR_ERR(slave_inode);
 714                 goto err_release;
 715         }
 716         tty->link->driver_data = slave_inode;
 717
 718         retval = ptm_driver->ops->open(tty, filp);
 719         if (retval)
 720                 goto err_release;
 721
 722         tty_unlock(tty);
 723         return 0;
 724 err_release:
 725         tty_unlock(tty);
 726         tty_release(inode, filp);
 727         return retval;
 728 out:
 729         mutex_unlock(&tty_mutex);
 730         devpts_kill_index(inode, index);
 731 err_file:
 732         tty_free_file(filp);
 733         return retval;
 734 }
 735
 736 static struct file_operations ptmx_fops;
 737
 738 static void __init unix98_pty_init(void)
 739 {
 740         ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
 741                         TTY_DRIVER_RESET_TERMIOS |
 742                         TTY_DRIVER_REAL_RAW |
 743                         TTY_DRIVER_DYNAMIC_DEV |
 744                         TTY_DRIVER_DEVPTS_MEM |
 745                         TTY_DRIVER_DYNAMIC_ALLOC);
 746         if (IS_ERR(ptm_driver))
 747                 panic("Couldn't allocate Unix98 ptm driver");
 748         pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
 749                         TTY_DRIVER_RESET_TERMIOS |
 750                         TTY_DRIVER_REAL_RAW |
 751                         TTY_DRIVER_DYNAMIC_DEV |
 752                         TTY_DRIVER_DEVPTS_MEM |
 753                         TTY_DRIVER_DYNAMIC_ALLOC);
 754         if (IS_ERR(pts_driver))
 755                 panic("Couldn't allocate Unix98 pts driver");
 756
 757         ptm_driver->driver_name = "pty_master";
 758         ptm_driver->name = "ptm";
 759         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
 760         ptm_driver->minor_start = 0;
 761         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
 762         ptm_driver->subtype = PTY_TYPE_MASTER;
 763         ptm_driver->init_termios = tty_std_termios;
 764         ptm_driver->init_termios.c_iflag = 0;
 765         ptm_driver->init_termios.c_oflag = 0;
 766         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 767         ptm_driver->init_termios.c_lflag = 0;
 768         ptm_driver->init_termios.c_ispeed = 38400;
 769         ptm_driver->init_termios.c_ospeed = 38400;
 770         ptm_driver->other = pts_driver;
 771         tty_set_operations(ptm_driver, &ptm_unix98_ops);
 772
 773         pts_driver->driver_name = "pty_slave";
 774         pts_driver->name = "pts";
 775         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
 776         pts_driver->minor_start = 0;
 777         pts_driver->type = TTY_DRIVER_TYPE_PTY;
 778         pts_driver->subtype = PTY_TYPE_SLAVE;
 779         pts_driver->init_termios = tty_std_termios;
 780         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 781         pts_driver->init_termios.c_ispeed = 38400;
 782         pts_driver->init_termios.c_ospeed = 38400;
 783         pts_driver->other = ptm_driver;
 784         tty_set_operations(pts_driver, &pty_unix98_ops);
 785
 786         if (tty_register_driver(ptm_driver))
 787                 panic("Couldn't register Unix98 ptm driver");
 788         if (tty_register_driver(pts_driver))
 789                 panic("Couldn't register Unix98 pts driver");
 790
 791         /* Now create the /dev/ptmx special device */
 792         tty_default_fops(&ptmx_fops);
 793         ptmx_fops.open = ptmx_open;
 794
 795         cdev_init(&ptmx_cdev, &ptmx_fops);
 796         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
 797             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
 798                 panic("Couldn't register /dev/ptmx driver");
 799         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
 800 }
 801
 802 #else
 803 static inline void unix98_pty_init(void) { }
 804 #endif
 805
 806 static int __init pty_init(void)
 807 {
 808         legacy_pty_init();
 809         unix98_pty_init();
 810         return 0;
 811 }
 812 module_init(pty_init);