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 static void pty_flush_buffer(struct tty_struct *tty)
 175 {
 176         struct tty_struct *to = tty->link;
 177         unsigned long flags;
 178
 179         if (!to)
 180                 return;
 181         /* tty_buffer_flush(to); FIXME */
 182         if (to->packet) {
 183                 spin_lock_irqsave(&tty->ctrl_lock, flags);
 184                 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
 185                 wake_up_interruptible(&to->read_wait);
 186                 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 187         }
 188 }
 189
 190 static int pty_open(struct tty_struct *tty, struct file *filp)
 191 {
 192         int     retval = -ENODEV;
 193
 194         if (!tty || !tty->link)
 195                 goto out;
 196
 197         retval = -EIO;
 198         if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
 199                 goto out;
 200         if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
 201                 goto out;
 202         if (tty->link->count != 1)
 203                 goto out;
 204
 205         clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
 206         set_bit(TTY_THROTTLED, &tty->flags);
 207         retval = 0;
 208 out:
 209         return retval;
 210 }
 211
 212 static void pty_set_termios(struct tty_struct *tty,
 213                                         struct ktermios *old_termios)
 214 {
 215         tty->termios->c_cflag &= ~(CSIZE | PARENB);
 216         tty->termios->c_cflag |= (CS8 | CREAD);
 217 }
 218
 219 /**
 220  *      pty_do_resize           -       resize event
 221  *      @tty: tty being resized
 222  *      @ws: window size being set.
 223  *
 224  *      Update the termios variables and send the necessary signals to
 225  *      peform a terminal resize correctly
 226  */
 227
 228 int pty_resize(struct tty_struct *tty,  struct winsize *ws)
 229 {
 230         struct pid *pgrp, *rpgrp;
 231         unsigned long flags;
 232         struct tty_struct *pty = tty->link;
 233
 234         /* For a PTY we need to lock the tty side */
 235         mutex_lock(&tty->termios_mutex);
 236         if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
 237                 goto done;
 238
 239         /* Get the PID values and reference them so we can
 240            avoid holding the tty ctrl lock while sending signals.
 241            We need to lock these individually however. */
 242
 243         spin_lock_irqsave(&tty->ctrl_lock, flags);
 244         pgrp = get_pid(tty->pgrp);
 245         spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 246
 247         spin_lock_irqsave(&pty->ctrl_lock, flags);
 248         rpgrp = get_pid(pty->pgrp);
 249         spin_unlock_irqrestore(&pty->ctrl_lock, flags);
 250
 251         if (pgrp)
 252                 kill_pgrp(pgrp, SIGWINCH, 1);
 253         if (rpgrp != pgrp && rpgrp)
 254                 kill_pgrp(rpgrp, SIGWINCH, 1);
 255
 256         put_pid(pgrp);
 257         put_pid(rpgrp);
 258
 259         tty->winsize = *ws;
 260         pty->winsize = *ws;     /* Never used so will go away soon */
 261 done:
 262         mutex_unlock(&tty->termios_mutex);
 263         return 0;
 264 }
 265
 266 /* Traditional BSD devices */
 267 #ifdef CONFIG_LEGACY_PTYS
 268
 269 static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
 270 {
 271         struct tty_struct *o_tty;
 272         int idx = tty->index;
 273         int retval;
 274
 275         o_tty = alloc_tty_struct();
 276         if (!o_tty)
 277                 return -ENOMEM;
 278         if (!try_module_get(driver->other->owner)) {
 279                 /* This cannot in fact currently happen */
 280                 free_tty_struct(o_tty);
 281                 return -ENOMEM;
 282         }
 283         initialize_tty_struct(o_tty, driver->other, idx);
 284
 285         /* We always use new tty termios data so we can do this
 286            the easy way .. */
 287         retval = tty_init_termios(tty);
 288         if (retval)
 289                 goto free_mem_out;
 290
 291         retval = tty_init_termios(o_tty);
 292         if (retval) {
 293                 tty_free_termios(tty);
 294                 goto free_mem_out;
 295         }
 296
 297         /*
 298          * Everything allocated ... set up the o_tty structure.
 299          */
 300         driver->other->ttys[idx] = o_tty;
 301         tty_driver_kref_get(driver->other);
 302         if (driver->subtype == PTY_TYPE_MASTER)
 303                 o_tty->count++;
 304         /* Establish the links in both directions */
 305         tty->link   = o_tty;
 306         o_tty->link = tty;
 307
 308         tty_driver_kref_get(driver);
 309         tty->count++;
 310         driver->ttys[idx] = tty;
 311         return 0;
 312 free_mem_out:
 313         module_put(o_tty->driver->owner);
 314         free_tty_struct(o_tty);
 315         return -ENOMEM;
 316 }
 317
 318 static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
 319                          unsigned int cmd, unsigned long arg)
 320 {
 321         switch (cmd) {
 322         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 323                 return pty_set_lock(tty, (int __user *) arg);
 324         }
 325         return -ENOIOCTLCMD;
 326 }
 327
 328 static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
 329 module_param(legacy_count, int, 0);
 330
 331 /*
 332  * The master side of a pty can do TIOCSPTLCK and thus
 333  * has pty_bsd_ioctl.
 334  */
 335 static const struct tty_operations master_pty_ops_bsd = {
 336         .install = pty_install,
 337         .open = pty_open,
 338         .close = pty_close,
 339         .write = pty_write,
 340         .write_room = pty_write_room,
 341         .flush_buffer = pty_flush_buffer,
 342         .chars_in_buffer = pty_chars_in_buffer,
 343         .unthrottle = pty_unthrottle,
 344         .set_termios = pty_set_termios,
 345         .ioctl = pty_bsd_ioctl,
 346         .resize = pty_resize
 347 };
 348
 349 static const struct tty_operations slave_pty_ops_bsd = {
 350         .install = pty_install,
 351         .open = pty_open,
 352         .close = pty_close,
 353         .write = pty_write,
 354         .write_room = pty_write_room,
 355         .flush_buffer = pty_flush_buffer,
 356         .chars_in_buffer = pty_chars_in_buffer,
 357         .unthrottle = pty_unthrottle,
 358         .set_termios = pty_set_termios,
 359         .resize = pty_resize
 360 };
 361
 362 static void __init legacy_pty_init(void)
 363 {
 364         struct tty_driver *pty_driver, *pty_slave_driver;
 365
 366         if (legacy_count <= 0)
 367                 return;
 368
 369         pty_driver = alloc_tty_driver(legacy_count);
 370         if (!pty_driver)
 371                 panic("Couldn't allocate pty driver");
 372
 373         pty_slave_driver = alloc_tty_driver(legacy_count);
 374         if (!pty_slave_driver)
 375                 panic("Couldn't allocate pty slave driver");
 376
 377         pty_driver->owner = THIS_MODULE;
 378         pty_driver->driver_name = "pty_master";
 379         pty_driver->name = "pty";
 380         pty_driver->major = PTY_MASTER_MAJOR;
 381         pty_driver->minor_start = 0;
 382         pty_driver->type = TTY_DRIVER_TYPE_PTY;
 383         pty_driver->subtype = PTY_TYPE_MASTER;
 384         pty_driver->init_termios = tty_std_termios;
 385         pty_driver->init_termios.c_iflag = 0;
 386         pty_driver->init_termios.c_oflag = 0;
 387         pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 388         pty_driver->init_termios.c_lflag = 0;
 389         pty_driver->init_termios.c_ispeed = 38400;
 390         pty_driver->init_termios.c_ospeed = 38400;
 391         pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
 392         pty_driver->other = pty_slave_driver;
 393         tty_set_operations(pty_driver, &master_pty_ops_bsd);
 394
 395         pty_slave_driver->owner = THIS_MODULE;
 396         pty_slave_driver->driver_name = "pty_slave";
 397         pty_slave_driver->name = "ttyp";
 398         pty_slave_driver->major = PTY_SLAVE_MAJOR;
 399         pty_slave_driver->minor_start = 0;
 400         pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
 401         pty_slave_driver->subtype = PTY_TYPE_SLAVE;
 402         pty_slave_driver->init_termios = tty_std_termios;
 403         pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 404         pty_slave_driver->init_termios.c_ispeed = 38400;
 405         pty_slave_driver->init_termios.c_ospeed = 38400;
 406         pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
 407                                         TTY_DRIVER_REAL_RAW;
 408         pty_slave_driver->other = pty_driver;
 409         tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
 410
 411         if (tty_register_driver(pty_driver))
 412                 panic("Couldn't register pty driver");
 413         if (tty_register_driver(pty_slave_driver))
 414                 panic("Couldn't register pty slave driver");
 415 }
 416 #else
 417 static inline void legacy_pty_init(void) { }
 418 #endif
 419
 420 /* Unix98 devices */
 421 #ifdef CONFIG_UNIX98_PTYS
 422 /*
 423  * sysctl support for setting limits on the number of Unix98 ptys allocated.
 424  * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
 425  */
 426 int pty_limit = NR_UNIX98_PTY_DEFAULT;
 427 static int pty_limit_min;
 428 static int pty_limit_max = NR_UNIX98_PTY_MAX;
 429 static int pty_count;
 430
 431 static struct cdev ptmx_cdev;
 432
 433 static struct ctl_table pty_table[] = {
 434         {
 435                 .procname       = "max",
 436                 .maxlen         = sizeof(int),
 437                 .mode           = 0644,
 438                 .data           = &pty_limit,
 439                 .proc_handler   = proc_dointvec_minmax,
 440                 .extra1         = &pty_limit_min,
 441                 .extra2         = &pty_limit_max,
 442         }, {
 443                 .procname       = "nr",
 444                 .maxlen         = sizeof(int),
 445                 .mode           = 0444,
 446                 .data           = &pty_count,
 447                 .proc_handler   = proc_dointvec,
 448         },
 449         {}
 450 };
 451
 452 static struct ctl_table pty_kern_table[] = {
 453         {
 454                 .procname       = "pty",
 455                 .mode           = 0555,
 456                 .child          = pty_table,
 457         },
 458         {}
 459 };
 460
 461 static struct ctl_table pty_root_table[] = {
 462         {
 463                 .procname       = "kernel",
 464                 .mode           = 0555,
 465                 .child          = pty_kern_table,
 466         },
 467         {}
 468 };
 469
 470
 471 static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
 472                             unsigned int cmd, unsigned long arg)
 473 {
 474         switch (cmd) {
 475         case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
 476                 return pty_set_lock(tty, (int __user *)arg);
 477         case TIOCGPTN: /* Get PT Number */
 478                 return put_user(tty->index, (unsigned int __user *)arg);
 479         }
 480
 481         return -ENOIOCTLCMD;
 482 }
 483
 484 /**
 485  *      ptm_unix98_lookup       -       find a pty master
 486  *      @driver: ptm driver
 487  *      @idx: tty index
 488  *
 489  *      Look up a pty master device. Called under the tty_mutex for now.
 490  *      This provides our locking.
 491  */
 492
 493 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
 494                 struct inode *ptm_inode, int idx)
 495 {
 496         struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
 497         if (tty)
 498                 tty = tty->link;
 499         return tty;
 500 }
 501
 502 /**
 503  *      pts_unix98_lookup       -       find a pty slave
 504  *      @driver: pts driver
 505  *      @idx: tty index
 506  *
 507  *      Look up a pty master device. Called under the tty_mutex for now.
 508  *      This provides our locking.
 509  */
 510
 511 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
 512                 struct inode *pts_inode, int idx)
 513 {
 514         struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
 515         /* Master must be open before slave */
 516         if (!tty)
 517                 return ERR_PTR(-EIO);
 518         return tty;
 519 }
 520
 521 static void pty_unix98_shutdown(struct tty_struct *tty)
 522 {
 523         /* We have our own method as we don't use the tty index */
 524         kfree(tty->termios);
 525 }
 526
 527 /* We have no need to install and remove our tty objects as devpts does all
 528    the work for us */
 529
 530 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
 531 {
 532         struct tty_struct *o_tty;
 533         int idx = tty->index;
 534
 535         o_tty = alloc_tty_struct();
 536         if (!o_tty)
 537                 return -ENOMEM;
 538         if (!try_module_get(driver->other->owner)) {
 539                 /* This cannot in fact currently happen */
 540                 free_tty_struct(o_tty);
 541                 return -ENOMEM;
 542         }
 543         initialize_tty_struct(o_tty, driver->other, idx);
 544
 545         tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 546         if (tty->termios == NULL)
 547                 goto free_mem_out;
 548         *tty->termios = driver->init_termios;
 549         tty->termios_locked = tty->termios + 1;
 550
 551         o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
 552         if (o_tty->termios == NULL)
 553                 goto free_mem_out;
 554         *o_tty->termios = driver->other->init_termios;
 555         o_tty->termios_locked = o_tty->termios + 1;
 556
 557         tty_driver_kref_get(driver->other);
 558         if (driver->subtype == PTY_TYPE_MASTER)
 559                 o_tty->count++;
 560         /* Establish the links in both directions */
 561         tty->link   = o_tty;
 562         o_tty->link = tty;
 563         /*
 564          * All structures have been allocated, so now we install them.
 565          * Failures after this point use release_tty to clean up, so
 566          * there's no need to null out the local pointers.
 567          */
 568         tty_driver_kref_get(driver);
 569         tty->count++;
 570         pty_count++;
 571         return 0;
 572 free_mem_out:
 573         kfree(o_tty->termios);
 574         module_put(o_tty->driver->owner);
 575         free_tty_struct(o_tty);
 576         kfree(tty->termios);
 577         return -ENOMEM;
 578 }
 579
 580 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 581 {
 582         pty_count--;
 583 }
 584
 585 static const struct tty_operations ptm_unix98_ops = {
 586         .lookup = ptm_unix98_lookup,
 587         .install = pty_unix98_install,
 588         .remove = pty_unix98_remove,
 589         .open = pty_open,
 590         .close = pty_close,
 591         .write = pty_write,
 592         .write_room = pty_write_room,
 593         .flush_buffer = pty_flush_buffer,
 594         .chars_in_buffer = pty_chars_in_buffer,
 595         .unthrottle = pty_unthrottle,
 596         .set_termios = pty_set_termios,
 597         .ioctl = pty_unix98_ioctl,
 598         .shutdown = pty_unix98_shutdown,
 599         .resize = pty_resize
 600 };
 601
 602 static const struct tty_operations pty_unix98_ops = {
 603         .lookup = pts_unix98_lookup,
 604         .install = pty_unix98_install,
 605         .remove = pty_unix98_remove,
 606         .open = pty_open,
 607         .close = pty_close,
 608         .write = pty_write,
 609         .write_room = pty_write_room,
 610         .flush_buffer = pty_flush_buffer,
 611         .chars_in_buffer = pty_chars_in_buffer,
 612         .unthrottle = pty_unthrottle,
 613         .set_termios = pty_set_termios,
 614         .shutdown = pty_unix98_shutdown
 615 };
 616
 617 /**
 618  *      ptmx_open               -       open a unix 98 pty master
 619  *      @inode: inode of device file
 620  *      @filp: file pointer to tty
 621  *
 622  *      Allocate a unix98 pty master device from the ptmx driver.
 623  *
 624  *      Locking: tty_mutex protects the init_dev work. tty->count should
 625  *              protect the rest.
 626  *              allocated_ptys_lock handles the list of free pty numbers
 627  */
 628
 629 static int __ptmx_open(struct inode *inode, struct file *filp)
 630 {
 631         struct tty_struct *tty;
 632         int retval;
 633         int index;
 634
 635         nonseekable_open(inode, filp);
 636
 637         /* find a device that is not in use. */
 638         index = devpts_new_index(inode);
 639         if (index < 0)
 640                 return index;
 641
 642         mutex_lock(&tty_mutex);
 643         tty = tty_init_dev(ptm_driver, index, 1);
 644         mutex_unlock(&tty_mutex);
 645
 646         if (IS_ERR(tty)) {
 647                 retval = PTR_ERR(tty);
 648                 goto out;
 649         }
 650
 651         set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
 652         filp->private_data = tty;
 653         file_move(filp, &tty->tty_files);
 654
 655         retval = devpts_pty_new(inode, tty->link);
 656         if (retval)
 657                 goto out1;
 658
 659         retval = ptm_driver->ops->open(tty, filp);
 660         if (!retval)
 661                 return 0;
 662 out1:
 663         tty_release(inode, filp);
 664         return retval;
 665 out:
 666         devpts_kill_index(inode, index);
 667         return retval;
 668 }
 669
 670 static int ptmx_open(struct inode *inode, struct file *filp)
 671 {
 672         int ret;
 673
 674         lock_kernel();
 675         ret = __ptmx_open(inode, filp);
 676         unlock_kernel();
 677         return ret;
 678 }
 679
 680 static struct file_operations ptmx_fops;
 681
 682 static void __init unix98_pty_init(void)
 683 {
 684         ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
 685         if (!ptm_driver)
 686                 panic("Couldn't allocate Unix98 ptm driver");
 687         pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
 688         if (!pts_driver)
 689                 panic("Couldn't allocate Unix98 pts driver");
 690
 691         ptm_driver->owner = THIS_MODULE;
 692         ptm_driver->driver_name = "pty_master";
 693         ptm_driver->name = "ptm";
 694         ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
 695         ptm_driver->minor_start = 0;
 696         ptm_driver->type = TTY_DRIVER_TYPE_PTY;
 697         ptm_driver->subtype = PTY_TYPE_MASTER;
 698         ptm_driver->init_termios = tty_std_termios;
 699         ptm_driver->init_termios.c_iflag = 0;
 700         ptm_driver->init_termios.c_oflag = 0;
 701         ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 702         ptm_driver->init_termios.c_lflag = 0;
 703         ptm_driver->init_termios.c_ispeed = 38400;
 704         ptm_driver->init_termios.c_ospeed = 38400;
 705         ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 706                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
 707         ptm_driver->other = pts_driver;
 708         tty_set_operations(ptm_driver, &ptm_unix98_ops);
 709
 710         pts_driver->owner = THIS_MODULE;
 711         pts_driver->driver_name = "pty_slave";
 712         pts_driver->name = "pts";
 713         pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
 714         pts_driver->minor_start = 0;
 715         pts_driver->type = TTY_DRIVER_TYPE_PTY;
 716         pts_driver->subtype = PTY_TYPE_SLAVE;
 717         pts_driver->init_termios = tty_std_termios;
 718         pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
 719         pts_driver->init_termios.c_ispeed = 38400;
 720         pts_driver->init_termios.c_ospeed = 38400;
 721         pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
 722                 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
 723         pts_driver->other = ptm_driver;
 724         tty_set_operations(pts_driver, &pty_unix98_ops);
 725
 726         if (tty_register_driver(ptm_driver))
 727                 panic("Couldn't register Unix98 ptm driver");
 728         if (tty_register_driver(pts_driver))
 729                 panic("Couldn't register Unix98 pts driver");
 730
 731         register_sysctl_table(pty_root_table);
 732
 733         /* Now create the /dev/ptmx special device */
 734         tty_default_fops(&ptmx_fops);
 735         ptmx_fops.open = ptmx_open;
 736
 737         cdev_init(&ptmx_cdev, &ptmx_fops);
 738         if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
 739             register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
 740                 panic("Couldn't register /dev/ptmx driver\n");
 741         device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
 742 }
 743
 744 #else
 745 static inline void unix98_pty_init(void) { }
 746 #endif
 747
 748 static int __init pty_init(void)
 749 {
 750         legacy_pty_init();
 751         unix98_pty_init();
 752         return 0;
 753 }
 754 module_init(pty_init);