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 #include <linux/poll.h> 28 29 30 #ifdef CONFIG_UNIX98_PTYS 31 static struct tty_driver *ptm_driver; 32 static struct tty_driver *pts_driver; 33 static DEFINE_MUTEX(devpts_mutex); 34 #endif 35 36 static void pty_close(struct tty_struct *tty, struct file *filp) 37 { 38 BUG_ON(!tty); 39 if (tty->driver->subtype == PTY_TYPE_MASTER) 40 WARN_ON(tty->count > 1); 41 else { 42 if (test_bit(TTY_IO_ERROR, &tty->flags)) 43 return; 44 if (tty->count > 2) 45 return; 46 } 47 set_bit(TTY_IO_ERROR, &tty->flags); 48 wake_up_interruptible(&tty->read_wait); 49 wake_up_interruptible(&tty->write_wait); 50 spin_lock_irq(&tty->ctrl_lock); 51 tty->packet = 0; 52 spin_unlock_irq(&tty->ctrl_lock); 53 /* Review - krefs on tty_link ?? */ 54 if (!tty->link) 55 return; 56 set_bit(TTY_OTHER_CLOSED, &tty->link->flags); 57 tty_flip_buffer_push(tty->link->port); 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 mutex_lock(&devpts_mutex); 64 if (tty->link->driver_data) 65 devpts_pty_kill(tty->link->driver_data); 66 mutex_unlock(&devpts_mutex); 67 } 68 #endif 69 tty_vhangup(tty->link); 70 } 71 } 72 73 /* 74 * The unthrottle routine is called by the line discipline to signal 75 * that it can receive more characters. For PTY's, the TTY_THROTTLED 76 * flag is always set, to force the line discipline to always call the 77 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE 78 * characters in the queue. This is necessary since each time this 79 * happens, we need to wake up any sleeping processes that could be 80 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent() 81 * for the pty buffer to be drained. 82 */ 83 static void pty_unthrottle(struct tty_struct *tty) 84 { 85 tty_wakeup(tty->link); 86 set_bit(TTY_THROTTLED, &tty->flags); 87 } 88 89 /** 90 * pty_write - write to a pty 91 * @tty: the tty we write from 92 * @buf: kernel buffer of data 93 * @count: bytes to write 94 * 95 * Our "hardware" write method. Data is coming from the ldisc which 96 * may be in a non sleeping state. We simply throw this at the other 97 * end of the link as if we were an IRQ handler receiving stuff for 98 * the other side of the pty/tty pair. 99 */ 100 101 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c) 102 { 103 struct tty_struct *to = tty->link; 104 105 if (tty->stopped) 106 return 0; 107 108 if (c > 0) { 109 /* Stuff the data into the input queue of the other end */ 110 c = tty_insert_flip_string(to->port, buf, c); 111 /* And shovel */ 112 if (c) 113 tty_flip_buffer_push(to->port); 114 } 115 return c; 116 } 117 118 /** 119 * pty_write_room - write space 120 * @tty: tty we are writing from 121 * 122 * Report how many bytes the ldisc can send into the queue for 123 * the other device. 124 */ 125 126 static int pty_write_room(struct tty_struct *tty) 127 { 128 if (tty->stopped) 129 return 0; 130 return tty_buffer_space_avail(tty->link->port); 131 } 132 133 /** 134 * pty_chars_in_buffer - characters currently in our tx queue 135 * @tty: our tty 136 * 137 * Report how much we have in the transmit queue. As everything is 138 * instantly at the other end this is easy to implement. 139 */ 140 141 static int pty_chars_in_buffer(struct tty_struct *tty) 142 { 143 return 0; 144 } 145 146 /* Set the lock flag on a pty */ 147 static int pty_set_lock(struct tty_struct *tty, int __user *arg) 148 { 149 int val; 150 if (get_user(val, arg)) 151 return -EFAULT; 152 if (val) 153 set_bit(TTY_PTY_LOCK, &tty->flags); 154 else 155 clear_bit(TTY_PTY_LOCK, &tty->flags); 156 return 0; 157 } 158 159 static int pty_get_lock(struct tty_struct *tty, int __user *arg) 160 { 161 int locked = test_bit(TTY_PTY_LOCK, &tty->flags); 162 return put_user(locked, arg); 163 } 164 165 /* Set the packet mode on a pty */ 166 static int pty_set_pktmode(struct tty_struct *tty, int __user *arg) 167 { 168 int pktmode; 169 170 if (get_user(pktmode, arg)) 171 return -EFAULT; 172 173 spin_lock_irq(&tty->ctrl_lock); 174 if (pktmode) { 175 if (!tty->packet) { 176 tty->link->ctrl_status = 0; 177 smp_mb(); 178 tty->packet = 1; 179 } 180 } else 181 tty->packet = 0; 182 spin_unlock_irq(&tty->ctrl_lock); 183 184 return 0; 185 } 186 187 /* Get the packet mode of a pty */ 188 static int pty_get_pktmode(struct tty_struct *tty, int __user *arg) 189 { 190 int pktmode = tty->packet; 191 return put_user(pktmode, arg); 192 } 193 194 /* Send a signal to the slave */ 195 static int pty_signal(struct tty_struct *tty, int sig) 196 { 197 struct pid *pgrp; 198 199 if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP) 200 return -EINVAL; 201 202 if (tty->link) { 203 pgrp = tty_get_pgrp(tty->link); 204 if (pgrp) 205 kill_pgrp(pgrp, sig, 1); 206 put_pid(pgrp); 207 } 208 return 0; 209 } 210 211 static void pty_flush_buffer(struct tty_struct *tty) 212 { 213 struct tty_struct *to = tty->link; 214 struct tty_ldisc *ld; 215 216 if (!to) 217 return; 218 219 ld = tty_ldisc_ref(to); 220 tty_buffer_flush(to, ld); 221 if (ld) 222 tty_ldisc_deref(ld); 223 224 if (to->packet) { 225 spin_lock_irq(&tty->ctrl_lock); 226 tty->ctrl_status |= TIOCPKT_FLUSHWRITE; 227 wake_up_interruptible(&to->read_wait); 228 spin_unlock_irq(&tty->ctrl_lock); 229 } 230 } 231 232 static int pty_open(struct tty_struct *tty, struct file *filp) 233 { 234 if (!tty || !tty->link) 235 return -ENODEV; 236 237 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) 238 goto out; 239 if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) 240 goto out; 241 if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1) 242 goto out; 243 244 clear_bit(TTY_IO_ERROR, &tty->flags); 245 /* TTY_OTHER_CLOSED must be cleared before TTY_OTHER_DONE */ 246 clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); 247 clear_bit(TTY_OTHER_DONE, &tty->link->flags); 248 set_bit(TTY_THROTTLED, &tty->flags); 249 return 0; 250 251 out: 252 set_bit(TTY_IO_ERROR, &tty->flags); 253 return -EIO; 254 } 255 256 static void pty_set_termios(struct tty_struct *tty, 257 struct ktermios *old_termios) 258 { 259 /* See if packet mode change of state. */ 260 if (tty->link && tty->link->packet) { 261 int extproc = (old_termios->c_lflag & EXTPROC) | 262 (tty->termios.c_lflag & EXTPROC); 263 int old_flow = ((old_termios->c_iflag & IXON) && 264 (old_termios->c_cc[VSTOP] == '\023') && 265 (old_termios->c_cc[VSTART] == '\021')); 266 int new_flow = (I_IXON(tty) && 267 STOP_CHAR(tty) == '\023' && 268 START_CHAR(tty) == '\021'); 269 if ((old_flow != new_flow) || extproc) { 270 spin_lock_irq(&tty->ctrl_lock); 271 if (old_flow != new_flow) { 272 tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); 273 if (new_flow) 274 tty->ctrl_status |= TIOCPKT_DOSTOP; 275 else 276 tty->ctrl_status |= TIOCPKT_NOSTOP; 277 } 278 if (extproc) 279 tty->ctrl_status |= TIOCPKT_IOCTL; 280 spin_unlock_irq(&tty->ctrl_lock); 281 wake_up_interruptible(&tty->link->read_wait); 282 } 283 } 284 285 tty->termios.c_cflag &= ~(CSIZE | PARENB); 286 tty->termios.c_cflag |= (CS8 | CREAD); 287 } 288 289 /** 290 * pty_do_resize - resize event 291 * @tty: tty being resized 292 * @ws: window size being set. 293 * 294 * Update the termios variables and send the necessary signals to 295 * peform a terminal resize correctly 296 */ 297 298 static int pty_resize(struct tty_struct *tty, struct winsize *ws) 299 { 300 struct pid *pgrp, *rpgrp; 301 struct tty_struct *pty = tty->link; 302 303 /* For a PTY we need to lock the tty side */ 304 mutex_lock(&tty->winsize_mutex); 305 if (!memcmp(ws, &tty->winsize, sizeof(*ws))) 306 goto done; 307 308 /* Signal the foreground process group of both ptys */ 309 pgrp = tty_get_pgrp(tty); 310 rpgrp = tty_get_pgrp(pty); 311 312 if (pgrp) 313 kill_pgrp(pgrp, SIGWINCH, 1); 314 if (rpgrp != pgrp && rpgrp) 315 kill_pgrp(rpgrp, SIGWINCH, 1); 316 317 put_pid(pgrp); 318 put_pid(rpgrp); 319 320 tty->winsize = *ws; 321 pty->winsize = *ws; /* Never used so will go away soon */ 322 done: 323 mutex_unlock(&tty->winsize_mutex); 324 return 0; 325 } 326 327 /** 328 * pty_start - start() handler 329 * pty_stop - stop() handler 330 * @tty: tty being flow-controlled 331 * 332 * Propagates the TIOCPKT status to the master pty. 333 * 334 * NB: only the master pty can be in packet mode so only the slave 335 * needs start()/stop() handlers 336 */ 337 static void pty_start(struct tty_struct *tty) 338 { 339 unsigned long flags; 340 341 if (tty->link && tty->link->packet) { 342 spin_lock_irqsave(&tty->ctrl_lock, flags); 343 tty->ctrl_status &= ~TIOCPKT_STOP; 344 tty->ctrl_status |= TIOCPKT_START; 345 spin_unlock_irqrestore(&tty->ctrl_lock, flags); 346 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); 347 } 348 } 349 350 static void pty_stop(struct tty_struct *tty) 351 { 352 unsigned long flags; 353 354 if (tty->link && tty->link->packet) { 355 spin_lock_irqsave(&tty->ctrl_lock, flags); 356 tty->ctrl_status &= ~TIOCPKT_START; 357 tty->ctrl_status |= TIOCPKT_STOP; 358 spin_unlock_irqrestore(&tty->ctrl_lock, flags); 359 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); 360 } 361 } 362 363 /** 364 * pty_common_install - set up the pty pair 365 * @driver: the pty driver 366 * @tty: the tty being instantiated 367 * @legacy: true if this is BSD style 368 * 369 * Perform the initial set up for the tty/pty pair. Called from the 370 * tty layer when the port is first opened. 371 * 372 * Locking: the caller must hold the tty_mutex 373 */ 374 static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, 375 bool legacy) 376 { 377 struct tty_struct *o_tty; 378 struct tty_port *ports[2]; 379 int idx = tty->index; 380 int retval = -ENOMEM; 381 382 /* Opening the slave first has always returned -EIO */ 383 if (driver->subtype != PTY_TYPE_MASTER) 384 return -EIO; 385 386 ports[0] = kmalloc(sizeof **ports, GFP_KERNEL); 387 ports[1] = kmalloc(sizeof **ports, GFP_KERNEL); 388 if (!ports[0] || !ports[1]) 389 goto err; 390 if (!try_module_get(driver->other->owner)) { 391 /* This cannot in fact currently happen */ 392 goto err; 393 } 394 o_tty = alloc_tty_struct(driver->other, idx); 395 if (!o_tty) 396 goto err_put_module; 397 398 tty_set_lock_subclass(o_tty); 399 lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE); 400 401 if (legacy) { 402 /* We always use new tty termios data so we can do this 403 the easy way .. */ 404 retval = tty_init_termios(tty); 405 if (retval) 406 goto err_deinit_tty; 407 408 retval = tty_init_termios(o_tty); 409 if (retval) 410 goto err_free_termios; 411 412 driver->other->ttys[idx] = o_tty; 413 driver->ttys[idx] = tty; 414 } else { 415 memset(&tty->termios_locked, 0, sizeof(tty->termios_locked)); 416 tty->termios = driver->init_termios; 417 memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked)); 418 o_tty->termios = driver->other->init_termios; 419 } 420 421 /* 422 * Everything allocated ... set up the o_tty structure. 423 */ 424 tty_driver_kref_get(driver->other); 425 /* Establish the links in both directions */ 426 tty->link = o_tty; 427 o_tty->link = tty; 428 tty_port_init(ports[0]); 429 tty_port_init(ports[1]); 430 tty_buffer_set_limit(ports[0], 8192); 431 tty_buffer_set_limit(ports[1], 8192); 432 o_tty->port = ports[0]; 433 tty->port = ports[1]; 434 o_tty->port->itty = o_tty; 435 436 tty_buffer_set_lock_subclass(o_tty->port); 437 438 tty_driver_kref_get(driver); 439 tty->count++; 440 o_tty->count++; 441 return 0; 442 err_free_termios: 443 if (legacy) 444 tty_free_termios(tty); 445 err_deinit_tty: 446 deinitialize_tty_struct(o_tty); 447 free_tty_struct(o_tty); 448 err_put_module: 449 module_put(driver->other->owner); 450 err: 451 kfree(ports[0]); 452 kfree(ports[1]); 453 return retval; 454 } 455 456 static void pty_cleanup(struct tty_struct *tty) 457 { 458 tty_port_put(tty->port); 459 } 460 461 /* Traditional BSD devices */ 462 #ifdef CONFIG_LEGACY_PTYS 463 464 static int pty_install(struct tty_driver *driver, struct tty_struct *tty) 465 { 466 return pty_common_install(driver, tty, true); 467 } 468 469 static void pty_remove(struct tty_driver *driver, struct tty_struct *tty) 470 { 471 struct tty_struct *pair = tty->link; 472 driver->ttys[tty->index] = NULL; 473 if (pair) 474 pair->driver->ttys[pair->index] = NULL; 475 } 476 477 static int pty_bsd_ioctl(struct tty_struct *tty, 478 unsigned int cmd, unsigned long arg) 479 { 480 switch (cmd) { 481 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ 482 return pty_set_lock(tty, (int __user *) arg); 483 case TIOCGPTLCK: /* Get PT Lock status */ 484 return pty_get_lock(tty, (int __user *)arg); 485 case TIOCPKT: /* Set PT packet mode */ 486 return pty_set_pktmode(tty, (int __user *)arg); 487 case TIOCGPKT: /* Get PT packet mode */ 488 return pty_get_pktmode(tty, (int __user *)arg); 489 case TIOCSIG: /* Send signal to other side of pty */ 490 return pty_signal(tty, (int) arg); 491 case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */ 492 return -EINVAL; 493 } 494 return -ENOIOCTLCMD; 495 } 496 497 static int legacy_count = CONFIG_LEGACY_PTY_COUNT; 498 module_param(legacy_count, int, 0); 499 500 /* 501 * The master side of a pty can do TIOCSPTLCK and thus 502 * has pty_bsd_ioctl. 503 */ 504 static const struct tty_operations master_pty_ops_bsd = { 505 .install = pty_install, 506 .open = pty_open, 507 .close = pty_close, 508 .write = pty_write, 509 .write_room = pty_write_room, 510 .flush_buffer = pty_flush_buffer, 511 .chars_in_buffer = pty_chars_in_buffer, 512 .unthrottle = pty_unthrottle, 513 .ioctl = pty_bsd_ioctl, 514 .cleanup = pty_cleanup, 515 .resize = pty_resize, 516 .remove = pty_remove 517 }; 518 519 static const struct tty_operations slave_pty_ops_bsd = { 520 .install = pty_install, 521 .open = pty_open, 522 .close = pty_close, 523 .write = pty_write, 524 .write_room = pty_write_room, 525 .flush_buffer = pty_flush_buffer, 526 .chars_in_buffer = pty_chars_in_buffer, 527 .unthrottle = pty_unthrottle, 528 .set_termios = pty_set_termios, 529 .cleanup = pty_cleanup, 530 .resize = pty_resize, 531 .start = pty_start, 532 .stop = pty_stop, 533 .remove = pty_remove 534 }; 535 536 static void __init legacy_pty_init(void) 537 { 538 struct tty_driver *pty_driver, *pty_slave_driver; 539 540 if (legacy_count <= 0) 541 return; 542 543 pty_driver = tty_alloc_driver(legacy_count, 544 TTY_DRIVER_RESET_TERMIOS | 545 TTY_DRIVER_REAL_RAW | 546 TTY_DRIVER_DYNAMIC_ALLOC); 547 if (IS_ERR(pty_driver)) 548 panic("Couldn't allocate pty driver"); 549 550 pty_slave_driver = tty_alloc_driver(legacy_count, 551 TTY_DRIVER_RESET_TERMIOS | 552 TTY_DRIVER_REAL_RAW | 553 TTY_DRIVER_DYNAMIC_ALLOC); 554 if (IS_ERR(pty_slave_driver)) 555 panic("Couldn't allocate pty slave driver"); 556 557 pty_driver->driver_name = "pty_master"; 558 pty_driver->name = "pty"; 559 pty_driver->major = PTY_MASTER_MAJOR; 560 pty_driver->minor_start = 0; 561 pty_driver->type = TTY_DRIVER_TYPE_PTY; 562 pty_driver->subtype = PTY_TYPE_MASTER; 563 pty_driver->init_termios = tty_std_termios; 564 pty_driver->init_termios.c_iflag = 0; 565 pty_driver->init_termios.c_oflag = 0; 566 pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 567 pty_driver->init_termios.c_lflag = 0; 568 pty_driver->init_termios.c_ispeed = 38400; 569 pty_driver->init_termios.c_ospeed = 38400; 570 pty_driver->other = pty_slave_driver; 571 tty_set_operations(pty_driver, &master_pty_ops_bsd); 572 573 pty_slave_driver->driver_name = "pty_slave"; 574 pty_slave_driver->name = "ttyp"; 575 pty_slave_driver->major = PTY_SLAVE_MAJOR; 576 pty_slave_driver->minor_start = 0; 577 pty_slave_driver->type = TTY_DRIVER_TYPE_PTY; 578 pty_slave_driver->subtype = PTY_TYPE_SLAVE; 579 pty_slave_driver->init_termios = tty_std_termios; 580 pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 581 pty_slave_driver->init_termios.c_ispeed = 38400; 582 pty_slave_driver->init_termios.c_ospeed = 38400; 583 pty_slave_driver->other = pty_driver; 584 tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd); 585 586 if (tty_register_driver(pty_driver)) 587 panic("Couldn't register pty driver"); 588 if (tty_register_driver(pty_slave_driver)) 589 panic("Couldn't register pty slave driver"); 590 } 591 #else 592 static inline void legacy_pty_init(void) { } 593 #endif 594 595 /* Unix98 devices */ 596 #ifdef CONFIG_UNIX98_PTYS 597 598 static struct cdev ptmx_cdev; 599 600 static int pty_unix98_ioctl(struct tty_struct *tty, 601 unsigned int cmd, unsigned long arg) 602 { 603 switch (cmd) { 604 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ 605 return pty_set_lock(tty, (int __user *)arg); 606 case TIOCGPTLCK: /* Get PT Lock status */ 607 return pty_get_lock(tty, (int __user *)arg); 608 case TIOCPKT: /* Set PT packet mode */ 609 return pty_set_pktmode(tty, (int __user *)arg); 610 case TIOCGPKT: /* Get PT packet mode */ 611 return pty_get_pktmode(tty, (int __user *)arg); 612 case TIOCGPTN: /* Get PT Number */ 613 return put_user(tty->index, (unsigned int __user *)arg); 614 case TIOCSIG: /* Send signal to other side of pty */ 615 return pty_signal(tty, (int) arg); 616 } 617 618 return -ENOIOCTLCMD; 619 } 620 621 /** 622 * ptm_unix98_lookup - find a pty master 623 * @driver: ptm driver 624 * @idx: tty index 625 * 626 * Look up a pty master device. Called under the tty_mutex for now. 627 * This provides our locking. 628 */ 629 630 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, 631 struct inode *ptm_inode, int idx) 632 { 633 /* Master must be open via /dev/ptmx */ 634 return ERR_PTR(-EIO); 635 } 636 637 /** 638 * pts_unix98_lookup - find a pty slave 639 * @driver: pts driver 640 * @idx: tty index 641 * 642 * Look up a pty master device. Called under the tty_mutex for now. 643 * This provides our locking for the tty pointer. 644 */ 645 646 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, 647 struct inode *pts_inode, int idx) 648 { 649 struct tty_struct *tty; 650 651 mutex_lock(&devpts_mutex); 652 tty = devpts_get_priv(pts_inode); 653 mutex_unlock(&devpts_mutex); 654 /* Master must be open before slave */ 655 if (!tty) 656 return ERR_PTR(-EIO); 657 return tty; 658 } 659 660 /* We have no need to install and remove our tty objects as devpts does all 661 the work for us */ 662 663 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) 664 { 665 return pty_common_install(driver, tty, false); 666 } 667 668 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) 669 { 670 } 671 672 /* this is called once with whichever end is closed last */ 673 static void pty_unix98_shutdown(struct tty_struct *tty) 674 { 675 devpts_kill_index(tty->driver_data, tty->index); 676 } 677 678 static const struct tty_operations ptm_unix98_ops = { 679 .lookup = ptm_unix98_lookup, 680 .install = pty_unix98_install, 681 .remove = pty_unix98_remove, 682 .open = pty_open, 683 .close = pty_close, 684 .write = pty_write, 685 .write_room = pty_write_room, 686 .flush_buffer = pty_flush_buffer, 687 .chars_in_buffer = pty_chars_in_buffer, 688 .unthrottle = pty_unthrottle, 689 .ioctl = pty_unix98_ioctl, 690 .resize = pty_resize, 691 .shutdown = pty_unix98_shutdown, 692 .cleanup = pty_cleanup 693 }; 694 695 static const struct tty_operations pty_unix98_ops = { 696 .lookup = pts_unix98_lookup, 697 .install = pty_unix98_install, 698 .remove = pty_unix98_remove, 699 .open = pty_open, 700 .close = pty_close, 701 .write = pty_write, 702 .write_room = pty_write_room, 703 .flush_buffer = pty_flush_buffer, 704 .chars_in_buffer = pty_chars_in_buffer, 705 .unthrottle = pty_unthrottle, 706 .set_termios = pty_set_termios, 707 .start = pty_start, 708 .stop = pty_stop, 709 .shutdown = pty_unix98_shutdown, 710 .cleanup = pty_cleanup, 711 }; 712 713 /** 714 * ptmx_open - open a unix 98 pty master 715 * @inode: inode of device file 716 * @filp: file pointer to tty 717 * 718 * Allocate a unix98 pty master device from the ptmx driver. 719 * 720 * Locking: tty_mutex protects the init_dev work. tty->count should 721 * protect the rest. 722 * allocated_ptys_lock handles the list of free pty numbers 723 */ 724 725 static int ptmx_open(struct inode *inode, struct file *filp) 726 { 727 struct tty_struct *tty; 728 struct inode *slave_inode; 729 int retval; 730 int index; 731 732 nonseekable_open(inode, filp); 733 734 /* We refuse fsnotify events on ptmx, since it's a shared resource */ 735 filp->f_mode |= FMODE_NONOTIFY; 736 737 retval = tty_alloc_file(filp); 738 if (retval) 739 return retval; 740 741 /* find a device that is not in use. */ 742 mutex_lock(&devpts_mutex); 743 index = devpts_new_index(inode); 744 if (index < 0) { 745 retval = index; 746 mutex_unlock(&devpts_mutex); 747 goto err_file; 748 } 749 750 mutex_unlock(&devpts_mutex); 751 752 mutex_lock(&tty_mutex); 753 tty = tty_init_dev(ptm_driver, index); 754 755 if (IS_ERR(tty)) { 756 retval = PTR_ERR(tty); 757 goto out; 758 } 759 760 /* The tty returned here is locked so we can safely 761 drop the mutex */ 762 mutex_unlock(&tty_mutex); 763 764 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ 765 tty->driver_data = inode; 766 767 tty_add_file(tty, filp); 768 769 slave_inode = devpts_pty_new(inode, 770 MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index, 771 tty->link); 772 if (IS_ERR(slave_inode)) { 773 retval = PTR_ERR(slave_inode); 774 goto err_release; 775 } 776 tty->link->driver_data = slave_inode; 777 778 retval = ptm_driver->ops->open(tty, filp); 779 if (retval) 780 goto err_release; 781 782 tty_unlock(tty); 783 return 0; 784 err_release: 785 tty_unlock(tty); 786 tty_release(inode, filp); 787 return retval; 788 out: 789 mutex_unlock(&tty_mutex); 790 devpts_kill_index(inode, index); 791 err_file: 792 tty_free_file(filp); 793 return retval; 794 } 795 796 static struct file_operations ptmx_fops; 797 798 static void __init unix98_pty_init(void) 799 { 800 ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, 801 TTY_DRIVER_RESET_TERMIOS | 802 TTY_DRIVER_REAL_RAW | 803 TTY_DRIVER_DYNAMIC_DEV | 804 TTY_DRIVER_DEVPTS_MEM | 805 TTY_DRIVER_DYNAMIC_ALLOC); 806 if (IS_ERR(ptm_driver)) 807 panic("Couldn't allocate Unix98 ptm driver"); 808 pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, 809 TTY_DRIVER_RESET_TERMIOS | 810 TTY_DRIVER_REAL_RAW | 811 TTY_DRIVER_DYNAMIC_DEV | 812 TTY_DRIVER_DEVPTS_MEM | 813 TTY_DRIVER_DYNAMIC_ALLOC); 814 if (IS_ERR(pts_driver)) 815 panic("Couldn't allocate Unix98 pts driver"); 816 817 ptm_driver->driver_name = "pty_master"; 818 ptm_driver->name = "ptm"; 819 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR; 820 ptm_driver->minor_start = 0; 821 ptm_driver->type = TTY_DRIVER_TYPE_PTY; 822 ptm_driver->subtype = PTY_TYPE_MASTER; 823 ptm_driver->init_termios = tty_std_termios; 824 ptm_driver->init_termios.c_iflag = 0; 825 ptm_driver->init_termios.c_oflag = 0; 826 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 827 ptm_driver->init_termios.c_lflag = 0; 828 ptm_driver->init_termios.c_ispeed = 38400; 829 ptm_driver->init_termios.c_ospeed = 38400; 830 ptm_driver->other = pts_driver; 831 tty_set_operations(ptm_driver, &ptm_unix98_ops); 832 833 pts_driver->driver_name = "pty_slave"; 834 pts_driver->name = "pts"; 835 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR; 836 pts_driver->minor_start = 0; 837 pts_driver->type = TTY_DRIVER_TYPE_PTY; 838 pts_driver->subtype = PTY_TYPE_SLAVE; 839 pts_driver->init_termios = tty_std_termios; 840 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 841 pts_driver->init_termios.c_ispeed = 38400; 842 pts_driver->init_termios.c_ospeed = 38400; 843 pts_driver->other = ptm_driver; 844 tty_set_operations(pts_driver, &pty_unix98_ops); 845 846 if (tty_register_driver(ptm_driver)) 847 panic("Couldn't register Unix98 ptm driver"); 848 if (tty_register_driver(pts_driver)) 849 panic("Couldn't register Unix98 pts driver"); 850 851 /* Now create the /dev/ptmx special device */ 852 tty_default_fops(&ptmx_fops); 853 ptmx_fops.open = ptmx_open; 854 855 cdev_init(&ptmx_cdev, &ptmx_fops); 856 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || 857 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) 858 panic("Couldn't register /dev/ptmx driver"); 859 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); 860 } 861 862 #else 863 static inline void unix98_pty_init(void) { } 864 #endif 865 866 static int __init pty_init(void) 867 { 868 legacy_pty_init(); 869 unix98_pty_init(); 870 return 0; 871 } 872 module_init(pty_init); 873