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/string.h>
  22 #include <linux/major.h>
  23 #include <linux/mm.h>
  24 #include <linux/init.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/sysctl.h>
  27 #include <linux/device.h>
  28 #include <linux/uaccess.h>
  29 #include <linux/bitops.h>
  30 #include <linux/devpts_fs.h>
  31
  32 #include <asm/system.h>
  33
  34 #ifdef CONFIG_UNIX98_PTYS
  35 static struct tty_driver *ptm_driver;
  36 static struct tty_driver *pts_driver;
  37 #endif
  38
  39 static void pty_close(struct tty_struct *tty, struct file *filp)
  40 {
  41         BUG_ON(!tty);
  42         if (tty->driver->subtype == PTY_TYPE_MASTER)
  43                 WARN_ON(tty->count > 1);
  44         else {
  45                 if (tty->count > 2)
  46                         return;
  47         }
  48         wake_up_interruptible(&tty->read_wait);
  49         wake_up_interruptible(&tty->write_wait);
  50         tty->packet = 0;
  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                         devpts_pty_kill(tty->link);
  62 #endif
  63                 tty_vhangup(tty->link);
  64         }
  65 }
  66
  67 /*
  68  * The unthrottle routine is called by the line discipline to signal
  69  * that it can receive more characters.  For PTY's, the TTY_THROTTLED
  70  * flag is always set, to force the line discipline to always call the
  71  * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
  72  * characters in the queue.  This is necessary since each time this
  73  * happens, we need to wake up any sleeping processes that could be
  74  * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
  75  * for the pty buffer to be drained.
  76  */
  77 static void pty_unthrottle(struct tty_struct *tty)
  78 {
  79         tty_wakeup(tty->link);
  80         set_bit(TTY_THROTTLED, &tty->flags);
  81 }
  82
  83 /**
  84  *      pty_space       -       report space left for writing
  85  *      @to: tty we are writing into
  86  *
  87  *      The tty buffers allow 64K but we sneak a peak and clip at 8K this
  88  *      allows a lot of overspill room for echo and other fun messes to
  89  *      be handled properly
  90  */
  91
  92 static int pty_space(struct tty_struct *to)
  93 {
  94         int n = 8192 - to->buf.memory_used;
  95         if (n < 0)
  96                 return 0;
  97         return n;
  98 }
  99
 100 /**
 101  *      pty_write               -       write to a pty
 102  *      @tty: the tty we write from
 103  *      @buf: kernel buffer of data
 104  *      @count: bytes to write
 105  *
 106  *      Our "hardware" write method. Data is coming from the ldisc which
 107  *      may be in a non sleeping state. We simply throw this at the other
 108  *      end of the link as if we were an IRQ handler receiving stuff for
 109  *      the other side of the pty/tty pair.
 110  */
 111
 112 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
 113 {
 114         struct tty_struct *to = tty->link;
 115
 116         if (tty->stopped)
 117                 return 0;
 118
 119         if (c > 0) {
 120                 /* Stuff the data into the input queue of the other end */
 121                 c = tty_insert_flip_string(to, buf, c);
 122                 /* And shovel */
 123                 if (c) {
 124                         tty_flip_buffer_push(to);
 125                         tty_wakeup(tty);
 126                 }
 127         }
 128         return c;
 129 }
 130
 131 /**
 132  *      pty_write_room  -       write space
 133  *      @tty: tty we are writing from
 134  *
 135  *      Report how many bytes the ldisc can send into the queue for
 136  *      the other device.
 137  */
 138
 139 static int pty_write_room(struct tty_struct *tty)
 140 {
 141         if (tty->stopped)
 142                 return 0;
 143         return pty_space(tty->link);
 144 }
 145
 146 /**
 147  *      pty_chars_in_buffer     -       characters currently in our tx queue
 148  *      @tty: our tty
 149  *
 150  *      Report how much we have in the transmit queue. As everything is
 151  *      instantly at the other end this is easy to implement.
 152  */
 153
 154 static int pty_chars_in_buffer(struct tty_struct *tty)
 155 {
 156         return 0;
 157 }
 158
 159 /* Set the lock flag on a pty */
 160 static int pty_set_lock(struct tty_struct *tty, int __user *arg)
 161 {
 162         int val;
 163         if (get_user(val, arg))
 164                 return -EFAULT;
 165         if (val)
 166                 set_bit(TTY_PTY_LOCK, &tty->flags);
 167         else
 168                 clear_bit(TTY_PTY_LOCK, &tty->flags);
 169         return 0;
 170 }
 171
 172 static void pty_flush_buffer(struct tty_struct *tty)
 173 {
 174         struct tty_struct *to = tty->link;
 175         unsigned long flags;
 176
 177         if (!to)
 178                 return;
 179         /* tty_buffer_flush(to); FIXME */
 180         if (to->packet) {
 181                 spin_lock_irqsave(&tty->ctrl_lock, flags);
 182                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
 183                 wake_up_interruptible(&to->read_wait);
 184                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 185         }
 186 }
 187
 188 static int pty_open(struct tty_struct *tty, struct file *filp)
 189 {
 190         int     retval = -ENODEV;
 191
 192         if (!tty || !tty->link)
 193                 goto out;
 194
 195         retval = -EIO;
 196         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
 197                 goto out;
 198         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
 199                 goto out;
 200         if (tty->link->count != 1)
 201                 goto out;
 202
 203         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
 204         set_bit(TTY_THROTTLED, &tty->flags);
 205         retval = 0;
 206 out:
 207         return retval;
 208 }
 209
 210 static void pty_set_termios(struct tty_struct *tty,
 211                                         struct ktermios *old_termios)
 212 {
 213         tty->termios->c_cflag &= ~(CSIZE | PARENB);
 214         tty->termios->c_cflag |= (CS8 | CREAD);
 215 }
 216
 217 /**
 218  *      pty_do_resize           -       resize event
 219  *      @tty: tty being resized
 220  *      @ws: window size being set.
 221  *
 222  *      Update the termios variables and send the neccessary signals to
 223  *      peform a terminal resize correctly
 224  */
 225
 226 int pty_resize(struct tty_struct *tty,  struct winsize *ws)
 227 {
 228         struct pid *pgrp, *rpgrp;
 229         unsigned long flags;
 230         struct tty_struct *pty = tty->link;
 231
 232         /* For a PTY we need to lock the tty side */
 233         mutex_lock(&tty->termios_mutex);
 234         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
 235                 goto done;
 236
 237         /* Get the PID values and reference them so we can
 238            avoid holding the tty ctrl lock while sending signals.
 239            We need to lock these individually however. */
 240
 241         spin_lock_irqsave(&tty->ctrl_lock, flags);
 242         pgrp = get_pid(tty->pgrp);
 243         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 244
 245         spin_lock_irqsave(&pty->ctrl_lock, flags);
 246         rpgrp = get_pid(pty->pgrp);
 247         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
 248
 249         if (pgrp)
 250                 kill_pgrp(pgrp, SIGWINCH, 1);
 251         if (rpgrp != pgrp && rpgrp)
 252                 kill_pgrp(rpgrp, SIGWINCH, 1);
 253
 254         put_pid(pgrp);
 255         put_pid(rpgrp);
 256
 257         tty->winsize = *ws;
 258         pty->winsize = *ws;     /* Never used so will go away soon */
 259 done:
 260         mutex_unlock(&tty->termios_mutex);
 261         return 0;
 262 }
 263
 264 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
 265 {
 266         struct tty_struct *o_tty;
 267         int idx = tty->index;
 268         int retval;
 269
 270         o_tty = alloc_tty_struct();
 271         if (!o_tty)
 272                 return -ENOMEM;
 273         if (!try_module_get(driver->other->owner)) {
 274                 /* This cannot in fact currently happen */
 275                 free_tty_struct(o_tty);
 276                 return -ENOMEM;
 277         }
 278         initialize_tty_struct(o_tty, driver->other, idx);
 279
 280         /* We always use new tty termios data so we can do this
 281            the easy way .. */
 282         retval = tty_init_termios(tty);
 283         if (retval)
 284                 goto free_mem_out;
 285
 286         retval = tty_init_termios(o_tty);
 287         if (retval) {
 288                 tty_free_termios(tty);
 289                 goto free_mem_out;
 290         }
 291
 292         /*
 293          * Everything allocated ... set up the o_tty structure.
 294          */
 295         driver->other->ttys[idx] = o_tty;
 296         tty_driver_kref_get(driver->other);
 297         if (driver->subtype == PTY_TYPE_MASTER)
 298                 o_tty->count++;
 299         /* Establish the links in both directions */
 300         tty->link   = o_tty;
 301         o_tty->link = tty;
 302
 303         tty_driver_kref_get(driver);
 304         tty->count++;
 305         driver->ttys[idx] = tty;
 306         return 0;
 307 free_mem_out:
 308         module_put(o_tty->driver->owner);
 309         free_tty_struct(o_tty);
 310         return -ENOMEM;
 311 }
 312
 313
 314 static const struct tty_operations pty_ops = {
 315         .install = pty_install,
 316         .open = pty_open,
 317         .close = pty_close,
 318         .write = pty_write,
 319         .write_room = pty_write_room,
 320         .flush_buffer = pty_flush_buffer,
 321         .chars_in_buffer = pty_chars_in_buffer,
 322         .unthrottle = pty_unthrottle,
 323         .set_termios = pty_set_termios,
 324         .resize = pty_resize
 325 };
 326
 327 /* Traditional BSD devices */
 328 #ifdef CONFIG_LEGACY_PTYS
 329 static struct tty_driver *pty_driver, *pty_slave_driver;
 330
 331 static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
 332                          unsigned int cmd, unsigned long arg)
 333 {
 334         switch (cmd) {
 335         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 336                 return pty_set_lock(tty, (int __user *) arg);
 337         }
 338         return -ENOIOCTLCMD;
 339 }
 340
 341 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
 342 module_param(legacy_count, int, 0);
 343
 344 static const struct tty_operations pty_ops_bsd = {
 345         .open = pty_open,
 346         .close = pty_close,
 347         .write = pty_write,
 348         .write_room = pty_write_room,
 349         .flush_buffer = pty_flush_buffer,
 350         .chars_in_buffer = pty_chars_in_buffer,
 351         .unthrottle = pty_unthrottle,
 352         .set_termios = pty_set_termios,
 353         .ioctl = pty_bsd_ioctl,
 354         .resize = pty_resize
 355 };
 356
 357 static void __init legacy_pty_init(void)
 358 {
 359         if (legacy_count <= 0)
 360                 return;
 361
 362         pty_driver = alloc_tty_driver(legacy_count);
 363         if (!pty_driver)
 364                 panic("Couldn't allocate pty driver");
 365
 366         pty_slave_driver = alloc_tty_driver(legacy_count);
 367         if (!pty_slave_driver)
 368                 panic("Couldn't allocate pty slave driver");
 369
 370         pty_driver->owner = THIS_MODULE;
 371         pty_driver->driver_name = "pty_master";
 372         pty_driver->name = "pty";
 373         pty_driver->major = PTY_MASTER_MAJOR;
 374         pty_driver->minor_start = 0;
 375         pty_driver->type = TTY_DRIVER_TYPE_PTY;
 376         pty_driver->subtype = PTY_TYPE_MASTER;
 377         pty_driver->init_termios = tty_std_termios;
 378         pty_driver->init_termios.c_iflag = 0;
 379         pty_driver->init_termios.c_oflag = 0;
 380         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 381         pty_driver->init_termios.c_lflag = 0;
 382         pty_driver->init_termios.c_ispeed = 38400;
 383         pty_driver->init_termios.c_ospeed = 38400;
 384         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
 385         pty_driver->other = pty_slave_driver;
 386         tty_set_operations(pty_driver, &pty_ops);
 387
 388         pty_slave_driver->owner = THIS_MODULE;
 389         pty_slave_driver->driver_name = "pty_slave";
 390         pty_slave_driver->name = "ttyp";
 391         pty_slave_driver->major = PTY_SLAVE_MAJOR;
 392         pty_slave_driver->minor_start = 0;
 393         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
 394         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
 395         pty_slave_driver->init_termios = tty_std_termios;
 396         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 397         pty_slave_driver->init_termios.c_ispeed = 38400;
 398         pty_slave_driver->init_termios.c_ospeed = 38400;
 399         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
 400                                         TTY_DRIVER_REAL_RAW;
 401         pty_slave_driver->other = pty_driver;
 402         tty_set_operations(pty_slave_driver, &pty_ops);
 403
 404         if (tty_register_driver(pty_driver))
 405                 panic("Couldn't register pty driver");
 406         if (tty_register_driver(pty_slave_driver))
 407                 panic("Couldn't register pty slave driver");
 408 }
 409 #else
 410 static inline void legacy_pty_init(void) { }
 411 #endif
 412
 413 /* Unix98 devices */
 414 #ifdef CONFIG_UNIX98_PTYS
 415 /*
 416  * sysctl support for setting limits on the number of Unix98 ptys allocated.
 417  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
 418  */
 419 int pty_limit = NR_UNIX98_PTY_DEFAULT;
 420 static int pty_limit_min;
 421 static int pty_limit_max = NR_UNIX98_PTY_MAX;
 422 static int pty_count;
 423
 424 static struct cdev ptmx_cdev;
 425
 426 static struct ctl_table pty_table[] = {
 427         {
 428                 .ctl_name       = PTY_MAX,
 429                 .procname       = "max",
 430                 .maxlen         = sizeof(int),
 431                 .mode           = 0644,
 432                 .data           = &pty_limit,
 433                 .proc_handler   = &proc_dointvec_minmax,
 434                 .strategy       = &sysctl_intvec,
 435                 .extra1         = &pty_limit_min,
 436                 .extra2         = &pty_limit_max,
 437         }, {
 438                 .ctl_name       = PTY_NR,
 439                 .procname       = "nr",
 440                 .maxlen         = sizeof(int),
 441                 .mode           = 0444,
 442                 .data           = &pty_count,
 443                 .proc_handler   = &proc_dointvec,
 444         }, {
 445                 .ctl_name       = 0
 446         }
 447 };
 448
 449 static struct ctl_table pty_kern_table[] = {
 450         {
 451                 .ctl_name       = KERN_PTY,
 452                 .procname       = "pty",
 453                 .mode           = 0555,
 454                 .child          = pty_table,
 455         },
 456         {}
 457 };
 458
 459 static struct ctl_table pty_root_table[] = {
 460         {
 461                 .ctl_name       = CTL_KERN,
 462                 .procname       = "kernel",
 463                 .mode           = 0555,
 464                 .child          = pty_kern_table,
 465         },
 466         {}
 467 };
 468
 469
 470 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
 471                             unsigned int cmd, unsigned long arg)
 472 {
 473         switch (cmd) {
 474         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 475                 return pty_set_lock(tty, (int __user *)arg);
 476         case TIOCGPTN: /* Get PT Number */
 477                 return put_user(tty->index, (unsigned int __user *)arg);
 478         }
 479
 480         return -ENOIOCTLCMD;
 481 }
 482
 483 /**
 484  *      ptm_unix98_lookup       -       find a pty master
 485  *      @driver: ptm driver
 486  *      @idx: tty index
 487  *
 488  *      Look up a pty master device. Called under the tty_mutex for now.
 489  *      This provides our locking.
 490  */
 491
 492 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
 493                 struct inode *ptm_inode, int idx)
 494 {
 495         struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
 496         if (tty)
 497                 tty = tty->link;
 498         return tty;
 499 }
 500
 501 /**
 502  *      pts_unix98_lookup       -       find a pty slave
 503  *      @driver: pts driver
 504  *      @idx: tty index
 505  *
 506  *      Look up a pty master device. Called under the tty_mutex for now.
 507  *      This provides our locking.
 508  */
 509
 510 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
 511                 struct inode *pts_inode, int idx)
 512 {
 513         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
 514         /* Master must be open before slave */
 515         if (!tty)
 516                 return ERR_PTR(-EIO);
 517         return tty;
 518 }
 519
 520 static void pty_unix98_shutdown(struct tty_struct *tty)
 521 {
 522         /* We have our own method as we don't use the tty index */
 523         kfree(tty->termios);
 524 }
 525
 526 /* We have no need to install and remove our tty objects as devpts does all
 527    the work for us */
 528
 529 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
 530 {
 531         struct tty_struct *o_tty;
 532         int idx = tty->index;
 533
 534         o_tty = alloc_tty_struct();
 535         if (!o_tty)
 536                 return -ENOMEM;
 537         if (!try_module_get(driver->other->owner)) {
 538                 /* This cannot in fact currently happen */
 539                 free_tty_struct(o_tty);
 540                 return -ENOMEM;
 541         }
 542         initialize_tty_struct(o_tty, driver->other, idx);
 543
 544         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 545         if (tty->termios == NULL)
 546                 goto free_mem_out;
 547         *tty->termios = driver->init_termios;
 548         tty->termios_locked = tty->termios + 1;
 549
 550         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 551         if (o_tty->termios == NULL)
 552                 goto free_mem_out;
 553         *o_tty->termios = driver->other->init_termios;
 554         o_tty->termios_locked = o_tty->termios + 1;
 555
 556         tty_driver_kref_get(driver->other);
 557         if (driver->subtype == PTY_TYPE_MASTER)
 558                 o_tty->count++;
 559         /* Establish the links in both directions */
 560         tty->link   = o_tty;
 561         o_tty->link = tty;
 562         /*
 563          * All structures have been allocated, so now we install them.
 564          * Failures after this point use release_tty to clean up, so
 565          * there's no need to null out the local pointers.
 566          */
 567         tty_driver_kref_get(driver);
 568         tty->count++;
 569         pty_count++;
 570         return 0;
 571 free_mem_out:
 572         kfree(o_tty->termios);
 573         module_put(o_tty->driver->owner);
 574         free_tty_struct(o_tty);
 575         kfree(tty->termios);
 576         return -ENOMEM;
 577 }
 578
 579 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 580 {
 581         pty_count--;
 582 }
 583
 584 static const struct tty_operations ptm_unix98_ops = {
 585         .lookup = ptm_unix98_lookup,
 586         .install = pty_unix98_install,
 587         .remove = pty_unix98_remove,
 588         .open = pty_open,
 589         .close = pty_close,
 590         .write = pty_write,
 591         .write_room = pty_write_room,
 592         .flush_buffer = pty_flush_buffer,
 593         .chars_in_buffer = pty_chars_in_buffer,
 594         .unthrottle = pty_unthrottle,
 595         .set_termios = pty_set_termios,
 596         .ioctl = pty_unix98_ioctl,
 597         .shutdown = pty_unix98_shutdown,
 598         .resize = pty_resize
 599 };
 600
 601 static const struct tty_operations pty_unix98_ops = {
 602         .lookup = pts_unix98_lookup,
 603         .install = pty_unix98_install,
 604         .remove = pty_unix98_remove,
 605         .open = pty_open,
 606         .close = pty_close,
 607         .write = pty_write,
 608         .write_room = pty_write_room,
 609         .flush_buffer = pty_flush_buffer,
 610         .chars_in_buffer = pty_chars_in_buffer,
 611         .unthrottle = pty_unthrottle,
 612         .set_termios = pty_set_termios,
 613         .shutdown = pty_unix98_shutdown
 614 };
 615
 616 /**
 617  *      ptmx_open               -       open a unix 98 pty master
 618  *      @inode: inode of device file
 619  *      @filp: file pointer to tty
 620  *
 621  *      Allocate a unix98 pty master device from the ptmx driver.
 622  *
 623  *      Locking: tty_mutex protects the init_dev work. tty->count should
 624  *              protect the rest.
 625  *              allocated_ptys_lock handles the list of free pty numbers
 626  */
 627
 628 static int __ptmx_open(struct inode *inode, struct file *filp)
 629 {
 630         struct tty_struct *tty;
 631         int retval;
 632         int index;
 633
 634         nonseekable_open(inode, filp);
 635
 636         /* find a device that is not in use. */
 637         index = devpts_new_index(inode);
 638         if (index < 0)
 639                 return index;
 640
 641         mutex_lock(&tty_mutex);
 642         tty = tty_init_dev(ptm_driver, index, 1);
 643         mutex_unlock(&tty_mutex);
 644
 645         if (IS_ERR(tty)) {
 646                 retval = PTR_ERR(tty);
 647                 goto out;
 648         }
 649
 650         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
 651         filp->private_data = tty;
 652         file_move(filp, &tty->tty_files);
 653
 654         retval = devpts_pty_new(inode, tty->link);
 655         if (retval)
 656                 goto out1;
 657
 658         retval = ptm_driver->ops->open(tty, filp);
 659         if (!retval)
 660                 return 0;
 661 out1:
 662         tty_release_dev(filp);
 663         return retval;
 664 out:
 665         devpts_kill_index(inode, index);
 666         return retval;
 667 }
 668
 669 static int ptmx_open(struct inode *inode, struct file *filp)
 670 {
 671         int ret;
 672
 673         lock_kernel();
 674         ret = __ptmx_open(inode, filp);
 675         unlock_kernel();
 676         return ret;
 677 }
 678
 679 static struct file_operations ptmx_fops;
 680
 681 static void __init unix98_pty_init(void)
 682 {
 683         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
 684         if (!ptm_driver)
 685                 panic("Couldn't allocate Unix98 ptm driver");
 686         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
 687         if (!pts_driver)
 688                 panic("Couldn't allocate Unix98 pts driver");
 689
 690         ptm_driver->owner = THIS_MODULE;
 691         ptm_driver->driver_name = "pty_master";
 692         ptm_driver->name = "ptm";
 693         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
 694         ptm_driver->minor_start = 0;
 695         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
 696         ptm_driver->subtype = PTY_TYPE_MASTER;
 697         ptm_driver->init_termios = tty_std_termios;
 698         ptm_driver->init_termios.c_iflag = 0;
 699         ptm_driver->init_termios.c_oflag = 0;
 700         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 701         ptm_driver->init_termios.c_lflag = 0;
 702         ptm_driver->init_termios.c_ispeed = 38400;
 703         ptm_driver->init_termios.c_ospeed = 38400;
 704         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 705                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
 706         ptm_driver->other = pts_driver;
 707         tty_set_operations(ptm_driver, &ptm_unix98_ops);
 708
 709         pts_driver->owner = THIS_MODULE;
 710         pts_driver->driver_name = "pty_slave";
 711         pts_driver->name = "pts";
 712         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
 713         pts_driver->minor_start = 0;
 714         pts_driver->type = TTY_DRIVER_TYPE_PTY;
 715         pts_driver->subtype = PTY_TYPE_SLAVE;
 716         pts_driver->init_termios = tty_std_termios;
 717         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 718         pts_driver->init_termios.c_ispeed = 38400;
 719         pts_driver->init_termios.c_ospeed = 38400;
 720         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 721                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
 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         register_sysctl_table(pty_root_table);
 731
 732         /* Now create the /dev/ptmx special device */
 733         tty_default_fops(&ptmx_fops);
 734         ptmx_fops.open = ptmx_open;
 735
 736         cdev_init(&ptmx_cdev, &ptmx_fops);
 737         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
 738             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
 739                 panic("Couldn't register /dev/ptmx driver\n");
 740         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
 741 }
 742
 743 #else
 744 static inline void unix98_pty_init(void) { }
 745 #endif
 746
 747 static int __init pty_init(void)
 748 {
 749         legacy_pty_init();
 750         unix98_pty_init();
 751         return 0;
 752 }
 753 module_init(pty_init);