drivers/char/pty.c

   1 /*
   2  *  linux/drivers/char/pty.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *
   6  *  Added support for a Unix98-style ptmx device.
   7  *    -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
   8  *
   9  *  When reading this code see also fs/devpts. In particular note that the
  10  *  driver_data field is used by the devpts side as a binding to the devpts
  11  *  inode.
  12  */
  13
  14 #include <linux/module.h>
  15
  16 #include <linux/errno.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/tty.h>
  19 #include <linux/tty_flip.h>
  20 #include <linux/fcntl.h>
  21 #include <linux/sched.h>
  22 #include <linux/string.h>
  23 #include <linux/major.h>
  24 #include <linux/mm.h>
  25 #include <linux/init.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/sysctl.h>
  28 #include <linux/device.h>
  29 #include <linux/uaccess.h>
  30 #include <linux/bitops.h>
  31 #include <linux/devpts_fs.h>
  32 #include <linux/slab.h>
  33
  34 #include <asm/system.h>
  35
  36 #ifdef CONFIG_UNIX98_PTYS
  37 static struct tty_driver *ptm_driver;
  38 static struct tty_driver *pts_driver;
  39 #endif
  40
  41 static void pty_close(struct tty_struct *tty, struct file *filp)
  42 {
  43         BUG_ON(!tty);
  44         if (tty->driver->subtype == PTY_TYPE_MASTER)
  45                 WARN_ON(tty->count > 1);
  46         else {
  47                 if (tty->count > 2)
  48                         return;
  49         }
  50         wake_up_interruptible(&tty->read_wait);
  51         wake_up_interruptible(&tty->write_wait);
  52         tty->packet = 0;
  53         if (!tty->link)
  54                 return;
  55         tty->link->packet = 0;
  56         set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
  57         wake_up_interruptible(&tty->link->read_wait);
  58         wake_up_interruptible(&tty->link->write_wait);
  59         if (tty->driver->subtype == PTY_TYPE_MASTER) {
  60                 set_bit(TTY_OTHER_CLOSED, &tty->flags);
  61 #ifdef CONFIG_UNIX98_PTYS
  62                 if (tty->driver == ptm_driver)
  63                         devpts_pty_kill(tty->link);
  64 #endif
  65                 tty_vhangup(tty->link);
  66         }
  67 }
  68
  69 /*
  70  * The unthrottle routine is called by the line discipline to signal
  71  * that it can receive more characters.  For PTY's, the TTY_THROTTLED
  72  * flag is always set, to force the line discipline to always call the
  73  * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
  74  * characters in the queue.  This is necessary since each time this
  75  * happens, we need to wake up any sleeping processes that could be
  76  * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
  77  * for the pty buffer to be drained.
  78  */
  79 static void pty_unthrottle(struct tty_struct *tty)
  80 {
  81         tty_wakeup(tty->link);
  82         set_bit(TTY_THROTTLED, &tty->flags);
  83 }
  84
  85 /**
  86  *      pty_space       -       report space left for writing
  87  *      @to: tty we are writing into
  88  *
  89  *      The tty buffers allow 64K but we sneak a peak and clip at 8K this
  90  *      allows a lot of overspill room for echo and other fun messes to
  91  *      be handled properly
  92  */
  93
  94 static int pty_space(struct tty_struct *to)
  95 {
  96         int n = 8192 - to->buf.memory_used;
  97         if (n < 0)
  98                 return 0;
  99         return n;
 100 }
 101
 102 /**
 103  *      pty_write               -       write to a pty
 104  *      @tty: the tty we write from
 105  *      @buf: kernel buffer of data
 106  *      @count: bytes to write
 107  *
 108  *      Our "hardware" write method. Data is coming from the ldisc which
 109  *      may be in a non sleeping state. We simply throw this at the other
 110  *      end of the link as if we were an IRQ handler receiving stuff for
 111  *      the other side of the pty/tty pair.
 112  */
 113
 114 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
 115 {
 116         struct tty_struct *to = tty->link;
 117
 118         if (tty->stopped)
 119                 return 0;
 120
 121         if (c > 0) {
 122                 /* Stuff the data into the input queue of the other end */
 123                 c = tty_insert_flip_string(to, buf, c);
 124                 /* And shovel */
 125                 if (c) {
 126                         tty_flip_buffer_push(to);
 127                         tty_wakeup(tty);
 128                 }
 129         }
 130         return c;
 131 }
 132
 133 /**
 134  *      pty_write_room  -       write space
 135  *      @tty: tty we are writing from
 136  *
 137  *      Report how many bytes the ldisc can send into the queue for
 138  *      the other device.
 139  */
 140
 141 static int pty_write_room(struct tty_struct *tty)
 142 {
 143         if (tty->stopped)
 144                 return 0;
 145         return pty_space(tty->link);
 146 }
 147
 148 /**
 149  *      pty_chars_in_buffer     -       characters currently in our tx queue
 150  *      @tty: our tty
 151  *
 152  *      Report how much we have in the transmit queue. As everything is
 153  *      instantly at the other end this is easy to implement.
 154  */
 155
 156 static int pty_chars_in_buffer(struct tty_struct *tty)
 157 {
 158         return 0;
 159 }
 160
 161 /* Set the lock flag on a pty */
 162 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
 163 {
 164         int val;
 165         if (get_user(val, arg))
 166                 return -EFAULT;
 167         if (val)
 168                 set_bit(TTY_PTY_LOCK, &tty->flags);
 169         else
 170                 clear_bit(TTY_PTY_LOCK, &tty->flags);
 171         return 0;
 172 }
 173
 174 /* Send a signal to the slave */
 175 static int pty_signal(struct tty_struct *tty, int sig)
 176 {
 177         unsigned long flags;
 178         struct pid *pgrp;
 179
 180         if (tty->link) {
 181                 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
 182                 pgrp = get_pid(tty->link->pgrp);
 183                 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
 184
 185                 kill_pgrp(pgrp, sig, 1);
 186                 put_pid(pgrp);
 187         }
 188         return 0;
 189 }
 190
 191 static void pty_flush_buffer(struct tty_struct *tty)
 192 {
 193         struct tty_struct *to = tty->link;
 194         unsigned long flags;
 195
 196         if (!to)
 197                 return;
 198         /* tty_buffer_flush(to); FIXME */
 199         if (to->packet) {
 200                 spin_lock_irqsave(&tty->ctrl_lock, flags);
 201                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
 202                 wake_up_interruptible(&to->read_wait);
 203                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 204         }
 205 }
 206
 207 static int pty_open(struct tty_struct *tty, struct file *filp)
 208 {
 209         int     retval = -ENODEV;
 210
 211         if (!tty || !tty->link)
 212                 goto out;
 213
 214         retval = -EIO;
 215         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
 216                 goto out;
 217         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
 218                 goto out;
 219         if (tty->link->count != 1)
 220                 goto out;
 221
 222         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
 223         set_bit(TTY_THROTTLED, &tty->flags);
 224         retval = 0;
 225 out:
 226         return retval;
 227 }
 228
 229 static void pty_set_termios(struct tty_struct *tty,
 230                                         struct ktermios *old_termios)
 231 {
 232         tty->termios->c_cflag &= ~(CSIZE | PARENB);
 233         tty->termios->c_cflag |= (CS8 | CREAD);
 234 }
 235
 236 /**
 237  *      pty_do_resize           -       resize event
 238  *      @tty: tty being resized
 239  *      @ws: window size being set.
 240  *
 241  *      Update the termios variables and send the necessary signals to
 242  *      peform a terminal resize correctly
 243  */
 244
 245 int pty_resize(struct tty_struct *tty,  struct winsize *ws)
 246 {
 247         struct pid *pgrp, *rpgrp;
 248         unsigned long flags;
 249         struct tty_struct *pty = tty->link;
 250
 251         /* For a PTY we need to lock the tty side */
 252         mutex_lock(&tty->termios_mutex);
 253         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
 254                 goto done;
 255
 256         /* Get the PID values and reference them so we can
 257            avoid holding the tty ctrl lock while sending signals.
 258            We need to lock these individually however. */
 259
 260         spin_lock_irqsave(&tty->ctrl_lock, flags);
 261         pgrp = get_pid(tty->pgrp);
 262         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 263
 264         spin_lock_irqsave(&pty->ctrl_lock, flags);
 265         rpgrp = get_pid(pty->pgrp);
 266         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
 267
 268         if (pgrp)
 269                 kill_pgrp(pgrp, SIGWINCH, 1);
 270         if (rpgrp != pgrp && rpgrp)
 271                 kill_pgrp(rpgrp, SIGWINCH, 1);
 272
 273         put_pid(pgrp);
 274         put_pid(rpgrp);
 275
 276         tty->winsize = *ws;
 277         pty->winsize = *ws;     /* Never used so will go away soon */
 278 done:
 279         mutex_unlock(&tty->termios_mutex);
 280         return 0;
 281 }
 282
 283 /* Traditional BSD devices */
 284 #ifdef CONFIG_LEGACY_PTYS
 285
 286 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
 287 {
 288         struct tty_struct *o_tty;
 289         int idx = tty->index;
 290         int retval;
 291
 292         o_tty = alloc_tty_struct();
 293         if (!o_tty)
 294                 return -ENOMEM;
 295         if (!try_module_get(driver->other->owner)) {
 296                 /* This cannot in fact currently happen */
 297                 free_tty_struct(o_tty);
 298                 return -ENOMEM;
 299         }
 300         initialize_tty_struct(o_tty, driver->other, idx);
 301
 302         /* We always use new tty termios data so we can do this
 303            the easy way .. */
 304         retval = tty_init_termios(tty);
 305         if (retval)
 306                 goto free_mem_out;
 307
 308         retval = tty_init_termios(o_tty);
 309         if (retval) {
 310                 tty_free_termios(tty);
 311                 goto free_mem_out;
 312         }
 313
 314         /*
 315          * Everything allocated ... set up the o_tty structure.
 316          */
 317         driver->other->ttys[idx] = o_tty;
 318         tty_driver_kref_get(driver->other);
 319         if (driver->subtype == PTY_TYPE_MASTER)
 320                 o_tty->count++;
 321         /* Establish the links in both directions */
 322         tty->link   = o_tty;
 323         o_tty->link = tty;
 324
 325         tty_driver_kref_get(driver);
 326         tty->count++;
 327         driver->ttys[idx] = tty;
 328         return 0;
 329 free_mem_out:
 330         module_put(o_tty->driver->owner);
 331         free_tty_struct(o_tty);
 332         return -ENOMEM;
 333 }
 334
 335 static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
 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->owner = THIS_MODULE;
 397         pty_driver->driver_name = "pty_master";
 398         pty_driver->name = "pty";
 399         pty_driver->major = PTY_MASTER_MAJOR;
 400         pty_driver->minor_start = 0;
 401         pty_driver->type = TTY_DRIVER_TYPE_PTY;
 402         pty_driver->subtype = PTY_TYPE_MASTER;
 403         pty_driver->init_termios = tty_std_termios;
 404         pty_driver->init_termios.c_iflag = 0;
 405         pty_driver->init_termios.c_oflag = 0;
 406         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 407         pty_driver->init_termios.c_lflag = 0;
 408         pty_driver->init_termios.c_ispeed = 38400;
 409         pty_driver->init_termios.c_ospeed = 38400;
 410         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
 411         pty_driver->other = pty_slave_driver;
 412         tty_set_operations(pty_driver, &master_pty_ops_bsd);
 413
 414         pty_slave_driver->owner = THIS_MODULE;
 415         pty_slave_driver->driver_name = "pty_slave";
 416         pty_slave_driver->name = "ttyp";
 417         pty_slave_driver->major = PTY_SLAVE_MAJOR;
 418         pty_slave_driver->minor_start = 0;
 419         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
 420         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
 421         pty_slave_driver->init_termios = tty_std_termios;
 422         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 423         pty_slave_driver->init_termios.c_ispeed = 38400;
 424         pty_slave_driver->init_termios.c_ospeed = 38400;
 425         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
 426                                         TTY_DRIVER_REAL_RAW;
 427         pty_slave_driver->other = pty_driver;
 428         tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
 429
 430         if (tty_register_driver(pty_driver))
 431                 panic("Couldn't register pty driver");
 432         if (tty_register_driver(pty_slave_driver))
 433                 panic("Couldn't register pty slave driver");
 434 }
 435 #else
 436 static inline void legacy_pty_init(void) { }
 437 #endif
 438
 439 /* Unix98 devices */
 440 #ifdef CONFIG_UNIX98_PTYS
 441 /*
 442  * sysctl support for setting limits on the number of Unix98 ptys allocated.
 443  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
 444  */
 445 int pty_limit = NR_UNIX98_PTY_DEFAULT;
 446 static int pty_limit_min;
 447 static int pty_limit_max = NR_UNIX98_PTY_MAX;
 448 static int pty_count;
 449
 450 static struct cdev ptmx_cdev;
 451
 452 static struct ctl_table pty_table[] = {
 453         {
 454                 .procname       = "max",
 455                 .maxlen         = sizeof(int),
 456                 .mode           = 0644,
 457                 .data           = &pty_limit,
 458                 .proc_handler   = proc_dointvec_minmax,
 459                 .extra1         = &pty_limit_min,
 460                 .extra2         = &pty_limit_max,
 461         }, {
 462                 .procname       = "nr",
 463                 .maxlen         = sizeof(int),
 464                 .mode           = 0444,
 465                 .data           = &pty_count,
 466                 .proc_handler   = proc_dointvec,
 467         },
 468         {}
 469 };
 470
 471 static struct ctl_table pty_kern_table[] = {
 472         {
 473                 .procname       = "pty",
 474                 .mode           = 0555,
 475                 .child          = pty_table,
 476         },
 477         {}
 478 };
 479
 480 static struct ctl_table pty_root_table[] = {
 481         {
 482                 .procname       = "kernel",
 483                 .mode           = 0555,
 484                 .child          = pty_kern_table,
 485         },
 486         {}
 487 };
 488
 489
 490 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
 491                             unsigned int cmd, unsigned long arg)
 492 {
 493         switch (cmd) {
 494         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 495                 return pty_set_lock(tty, (int __user *)arg);
 496         case TIOCGPTN: /* Get PT Number */
 497                 return put_user(tty->index, (unsigned int __user *)arg);
 498         case TIOCSIG:    /* Send signal to other side of pty */
 499                 return pty_signal(tty, (int) arg);
 500         }
 501
 502         return -ENOIOCTLCMD;
 503 }
 504
 505 /**
 506  *      ptm_unix98_lookup       -       find a pty master
 507  *      @driver: ptm driver
 508  *      @idx: tty index
 509  *
 510  *      Look up a pty master device. Called under the tty_mutex for now.
 511  *      This provides our locking.
 512  */
 513
 514 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
 515                 struct inode *ptm_inode, int idx)
 516 {
 517         struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
 518         if (tty)
 519                 tty = tty->link;
 520         return tty;
 521 }
 522
 523 /**
 524  *      pts_unix98_lookup       -       find a pty slave
 525  *      @driver: pts driver
 526  *      @idx: tty index
 527  *
 528  *      Look up a pty master device. Called under the tty_mutex for now.
 529  *      This provides our locking.
 530  */
 531
 532 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
 533                 struct inode *pts_inode, int idx)
 534 {
 535         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
 536         /* Master must be open before slave */
 537         if (!tty)
 538                 return ERR_PTR(-EIO);
 539         return tty;
 540 }
 541
 542 static void pty_unix98_shutdown(struct tty_struct *tty)
 543 {
 544         /* We have our own method as we don't use the tty index */
 545         kfree(tty->termios);
 546 }
 547
 548 /* We have no need to install and remove our tty objects as devpts does all
 549    the work for us */
 550
 551 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
 552 {
 553         struct tty_struct *o_tty;
 554         int idx = tty->index;
 555
 556         o_tty = alloc_tty_struct();
 557         if (!o_tty)
 558                 return -ENOMEM;
 559         if (!try_module_get(driver->other->owner)) {
 560                 /* This cannot in fact currently happen */
 561                 free_tty_struct(o_tty);
 562                 return -ENOMEM;
 563         }
 564         initialize_tty_struct(o_tty, driver->other, idx);
 565
 566         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 567         if (tty->termios == NULL)
 568                 goto free_mem_out;
 569         *tty->termios = driver->init_termios;
 570         tty->termios_locked = tty->termios + 1;
 571
 572         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 573         if (o_tty->termios == NULL)
 574                 goto free_mem_out;
 575         *o_tty->termios = driver->other->init_termios;
 576         o_tty->termios_locked = o_tty->termios + 1;
 577
 578         tty_driver_kref_get(driver->other);
 579         if (driver->subtype == PTY_TYPE_MASTER)
 580                 o_tty->count++;
 581         /* Establish the links in both directions */
 582         tty->link   = o_tty;
 583         o_tty->link = tty;
 584         /*
 585          * All structures have been allocated, so now we install them.
 586          * Failures after this point use release_tty to clean up, so
 587          * there's no need to null out the local pointers.
 588          */
 589         tty_driver_kref_get(driver);
 590         tty->count++;
 591         pty_count++;
 592         return 0;
 593 free_mem_out:
 594         kfree(o_tty->termios);
 595         module_put(o_tty->driver->owner);
 596         free_tty_struct(o_tty);
 597         kfree(tty->termios);
 598         return -ENOMEM;
 599 }
 600
 601 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 602 {
 603         pty_count--;
 604 }
 605
 606 static const struct tty_operations ptm_unix98_ops = {
 607         .lookup = ptm_unix98_lookup,
 608         .install = pty_unix98_install,
 609         .remove = pty_unix98_remove,
 610         .open = pty_open,
 611         .close = pty_close,
 612         .write = pty_write,
 613         .write_room = pty_write_room,
 614         .flush_buffer = pty_flush_buffer,
 615         .chars_in_buffer = pty_chars_in_buffer,
 616         .unthrottle = pty_unthrottle,
 617         .set_termios = pty_set_termios,
 618         .ioctl = pty_unix98_ioctl,
 619         .shutdown = pty_unix98_shutdown,
 620         .resize = pty_resize
 621 };
 622
 623 static const struct tty_operations pty_unix98_ops = {
 624         .lookup = pts_unix98_lookup,
 625         .install = pty_unix98_install,
 626         .remove = pty_unix98_remove,
 627         .open = pty_open,
 628         .close = pty_close,
 629         .write = pty_write,
 630         .write_room = pty_write_room,
 631         .flush_buffer = pty_flush_buffer,
 632         .chars_in_buffer = pty_chars_in_buffer,
 633         .unthrottle = pty_unthrottle,
 634         .set_termios = pty_set_termios,
 635         .shutdown = pty_unix98_shutdown
 636 };
 637
 638 /**
 639  *      ptmx_open               -       open a unix 98 pty master
 640  *      @inode: inode of device file
 641  *      @filp: file pointer to tty
 642  *
 643  *      Allocate a unix98 pty master device from the ptmx driver.
 644  *
 645  *      Locking: tty_mutex protects the init_dev work. tty->count should
 646  *              protect the rest.
 647  *              allocated_ptys_lock handles the list of free pty numbers
 648  */
 649
 650 static int __ptmx_open(struct inode *inode, struct file *filp)
 651 {
 652         struct tty_struct *tty;
 653         int retval;
 654         int index;
 655
 656         nonseekable_open(inode, filp);
 657
 658         /* find a device that is not in use. */
 659         index = devpts_new_index(inode);
 660         if (index < 0)
 661                 return index;
 662
 663         mutex_lock(&tty_mutex);
 664         tty = tty_init_dev(ptm_driver, index, 1);
 665         mutex_unlock(&tty_mutex);
 666
 667         if (IS_ERR(tty)) {
 668                 retval = PTR_ERR(tty);
 669                 goto out;
 670         }
 671
 672         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
 673         filp->private_data = tty;
 674         file_move(filp, &tty->tty_files);
 675
 676         retval = devpts_pty_new(inode, tty->link);
 677         if (retval)
 678                 goto out1;
 679
 680         retval = ptm_driver->ops->open(tty, filp);
 681         if (!retval)
 682                 return 0;
 683 out1:
 684         tty_release(inode, filp);
 685         return retval;
 686 out:
 687         devpts_kill_index(inode, index);
 688         return retval;
 689 }
 690
 691 static int ptmx_open(struct inode *inode, struct file *filp)
 692 {
 693         int ret;
 694
 695         tty_lock();
 696         ret = __ptmx_open(inode, filp);
 697         tty_unlock();
 698         return ret;
 699 }
 700
 701 static struct file_operations ptmx_fops;
 702
 703 static void __init unix98_pty_init(void)
 704 {
 705         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
 706         if (!ptm_driver)
 707                 panic("Couldn't allocate Unix98 ptm driver");
 708         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
 709         if (!pts_driver)
 710                 panic("Couldn't allocate Unix98 pts driver");
 711
 712         ptm_driver->owner = THIS_MODULE;
 713         ptm_driver->driver_name = "pty_master";
 714         ptm_driver->name = "ptm";
 715         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
 716         ptm_driver->minor_start = 0;
 717         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
 718         ptm_driver->subtype = PTY_TYPE_MASTER;
 719         ptm_driver->init_termios = tty_std_termios;
 720         ptm_driver->init_termios.c_iflag = 0;
 721         ptm_driver->init_termios.c_oflag = 0;
 722         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 723         ptm_driver->init_termios.c_lflag = 0;
 724         ptm_driver->init_termios.c_ispeed = 38400;
 725         ptm_driver->init_termios.c_ospeed = 38400;
 726         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 727                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
 728         ptm_driver->other = pts_driver;
 729         tty_set_operations(ptm_driver, &ptm_unix98_ops);
 730
 731         pts_driver->owner = THIS_MODULE;
 732         pts_driver->driver_name = "pty_slave";
 733         pts_driver->name = "pts";
 734         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
 735         pts_driver->minor_start = 0;
 736         pts_driver->type = TTY_DRIVER_TYPE_PTY;
 737         pts_driver->subtype = PTY_TYPE_SLAVE;
 738         pts_driver->init_termios = tty_std_termios;
 739         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 740         pts_driver->init_termios.c_ispeed = 38400;
 741         pts_driver->init_termios.c_ospeed = 38400;
 742         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 743                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
 744         pts_driver->other = ptm_driver;
 745         tty_set_operations(pts_driver, &pty_unix98_ops);
 746
 747         if (tty_register_driver(ptm_driver))
 748                 panic("Couldn't register Unix98 ptm driver");
 749         if (tty_register_driver(pts_driver))
 750                 panic("Couldn't register Unix98 pts driver");
 751
 752         register_sysctl_table(pty_root_table);
 753
 754         /* Now create the /dev/ptmx special device */
 755         tty_default_fops(&ptmx_fops);
 756         ptmx_fops.open = ptmx_open;
 757
 758         cdev_init(&ptmx_cdev, &ptmx_fops);
 759         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
 760             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
 761                 panic("Couldn't register /dev/ptmx driver\n");
 762         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
 763 }
 764
 765 #else
 766 static inline void unix98_pty_init(void) { }
 767 #endif
 768
 769 static int __init pty_init(void)
 770 {
 771         legacy_pty_init();
 772         unix98_pty_init();
 773         return 0;
 774 }
 775 module_init(pty_init);