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 #include <linux/errno.h> 11 #include <linux/interrupt.h> 12 #include <linux/tty.h> 13 #include <linux/tty_flip.h> 14 #include <linux/fcntl.h> 15 #include <linux/sched.h> 16 #include <linux/string.h> 17 #include <linux/major.h> 18 #include <linux/mm.h> 19 #include <linux/init.h> 20 #include <linux/device.h> 21 #include <linux/uaccess.h> 22 #include <linux/bitops.h> 23 #include <linux/devpts_fs.h> 24 #include <linux/slab.h> 25 #include <linux/mutex.h> 26 #include <linux/poll.h> 27 28 #undef TTY_DEBUG_HANGUP 29 #ifdef TTY_DEBUG_HANGUP 30 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args) 31 #else 32 # define tty_debug_hangup(tty, f, args...) do {} while (0) 33 #endif 34 35 #ifdef CONFIG_UNIX98_PTYS 36 static struct tty_driver *ptm_driver; 37 static struct tty_driver *pts_driver; 38 static DEFINE_MUTEX(devpts_mutex); 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 (test_bit(TTY_IO_ERROR, &tty->flags)) 48 return; 49 if (tty->count > 2) 50 return; 51 } 52 set_bit(TTY_IO_ERROR, &tty->flags); 53 wake_up_interruptible(&tty->read_wait); 54 wake_up_interruptible(&tty->write_wait); 55 spin_lock_irq(&tty->ctrl_lock); 56 tty->packet = 0; 57 spin_unlock_irq(&tty->ctrl_lock); 58 /* Review - krefs on tty_link ?? */ 59 if (!tty->link) 60 return; 61 set_bit(TTY_OTHER_CLOSED, &tty->link->flags); 62 tty_flip_buffer_push(tty->link->port); 63 wake_up_interruptible(&tty->link->write_wait); 64 if (tty->driver->subtype == PTY_TYPE_MASTER) { 65 set_bit(TTY_OTHER_CLOSED, &tty->flags); 66 #ifdef CONFIG_UNIX98_PTYS 67 if (tty->driver == ptm_driver) { 68 mutex_lock(&devpts_mutex); 69 if (tty->link->driver_data) 70 devpts_pty_kill(tty->link->driver_data); 71 mutex_unlock(&devpts_mutex); 72 } 73 #endif 74 tty_vhangup(tty->link); 75 } 76 } 77 78 /* 79 * The unthrottle routine is called by the line discipline to signal 80 * that it can receive more characters. For PTY's, the TTY_THROTTLED 81 * flag is always set, to force the line discipline to always call the 82 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE 83 * characters in the queue. This is necessary since each time this 84 * happens, we need to wake up any sleeping processes that could be 85 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent() 86 * for the pty buffer to be drained. 87 */ 88 static void pty_unthrottle(struct tty_struct *tty) 89 { 90 tty_wakeup(tty->link); 91 set_bit(TTY_THROTTLED, &tty->flags); 92 } 93 94 /** 95 * pty_write - write to a pty 96 * @tty: the tty we write from 97 * @buf: kernel buffer of data 98 * @count: bytes to write 99 * 100 * Our "hardware" write method. Data is coming from the ldisc which 101 * may be in a non sleeping state. We simply throw this at the other 102 * end of the link as if we were an IRQ handler receiving stuff for 103 * the other side of the pty/tty pair. 104 */ 105 106 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c) 107 { 108 struct tty_struct *to = tty->link; 109 110 if (tty->stopped) 111 return 0; 112 113 if (c > 0) { 114 /* Stuff the data into the input queue of the other end */ 115 c = tty_insert_flip_string(to->port, buf, c); 116 /* And shovel */ 117 if (c) 118 tty_flip_buffer_push(to->port); 119 } 120 return c; 121 } 122 123 /** 124 * pty_write_room - write space 125 * @tty: tty we are writing from 126 * 127 * Report how many bytes the ldisc can send into the queue for 128 * the other device. 129 */ 130 131 static int pty_write_room(struct tty_struct *tty) 132 { 133 if (tty->stopped) 134 return 0; 135 return tty_buffer_space_avail(tty->link->port); 136 } 137 138 /** 139 * pty_chars_in_buffer - characters currently in our tx queue 140 * @tty: our tty 141 * 142 * Report how much we have in the transmit queue. As everything is 143 * instantly at the other end this is easy to implement. 144 */ 145 146 static int pty_chars_in_buffer(struct tty_struct *tty) 147 { 148 return 0; 149 } 150 151 /* Set the lock flag on a pty */ 152 static int pty_set_lock(struct tty_struct *tty, int __user *arg) 153 { 154 int val; 155 if (get_user(val, arg)) 156 return -EFAULT; 157 if (val) 158 set_bit(TTY_PTY_LOCK, &tty->flags); 159 else 160 clear_bit(TTY_PTY_LOCK, &tty->flags); 161 return 0; 162 } 163 164 static int pty_get_lock(struct tty_struct *tty, int __user *arg) 165 { 166 int locked = test_bit(TTY_PTY_LOCK, &tty->flags); 167 return put_user(locked, arg); 168 } 169 170 /* Set the packet mode on a pty */ 171 static int pty_set_pktmode(struct tty_struct *tty, int __user *arg) 172 { 173 int pktmode; 174 175 if (get_user(pktmode, arg)) 176 return -EFAULT; 177 178 spin_lock_irq(&tty->ctrl_lock); 179 if (pktmode) { 180 if (!tty->packet) { 181 tty->link->ctrl_status = 0; 182 smp_mb(); 183 tty->packet = 1; 184 } 185 } else 186 tty->packet = 0; 187 spin_unlock_irq(&tty->ctrl_lock); 188 189 return 0; 190 } 191 192 /* Get the packet mode of a pty */ 193 static int pty_get_pktmode(struct tty_struct *tty, int __user *arg) 194 { 195 int pktmode = tty->packet; 196 return put_user(pktmode, arg); 197 } 198 199 /* Send a signal to the slave */ 200 static int pty_signal(struct tty_struct *tty, int sig) 201 { 202 struct pid *pgrp; 203 204 if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP) 205 return -EINVAL; 206 207 if (tty->link) { 208 pgrp = tty_get_pgrp(tty->link); 209 if (pgrp) 210 kill_pgrp(pgrp, sig, 1); 211 put_pid(pgrp); 212 } 213 return 0; 214 } 215 216 static void pty_flush_buffer(struct tty_struct *tty) 217 { 218 struct tty_struct *to = tty->link; 219 struct tty_ldisc *ld; 220 221 if (!to) 222 return; 223 224 ld = tty_ldisc_ref(to); 225 tty_buffer_flush(to, ld); 226 if (ld) 227 tty_ldisc_deref(ld); 228 229 if (to->packet) { 230 spin_lock_irq(&tty->ctrl_lock); 231 tty->ctrl_status |= TIOCPKT_FLUSHWRITE; 232 wake_up_interruptible(&to->read_wait); 233 spin_unlock_irq(&tty->ctrl_lock); 234 } 235 } 236 237 static int pty_open(struct tty_struct *tty, struct file *filp) 238 { 239 if (!tty || !tty->link) 240 return -ENODEV; 241 242 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) 243 goto out; 244 if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) 245 goto out; 246 if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1) 247 goto out; 248 249 clear_bit(TTY_IO_ERROR, &tty->flags); 250 /* TTY_OTHER_CLOSED must be cleared before TTY_OTHER_DONE */ 251 clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); 252 clear_bit(TTY_OTHER_DONE, &tty->link->flags); 253 set_bit(TTY_THROTTLED, &tty->flags); 254 return 0; 255 256 out: 257 set_bit(TTY_IO_ERROR, &tty->flags); 258 return -EIO; 259 } 260 261 static void pty_set_termios(struct tty_struct *tty, 262 struct ktermios *old_termios) 263 { 264 /* See if packet mode change of state. */ 265 if (tty->link && tty->link->packet) { 266 int extproc = (old_termios->c_lflag & EXTPROC) | 267 (tty->termios.c_lflag & EXTPROC); 268 int old_flow = ((old_termios->c_iflag & IXON) && 269 (old_termios->c_cc[VSTOP] == '\023') && 270 (old_termios->c_cc[VSTART] == '\021')); 271 int new_flow = (I_IXON(tty) && 272 STOP_CHAR(tty) == '\023' && 273 START_CHAR(tty) == '\021'); 274 if ((old_flow != new_flow) || extproc) { 275 spin_lock_irq(&tty->ctrl_lock); 276 if (old_flow != new_flow) { 277 tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); 278 if (new_flow) 279 tty->ctrl_status |= TIOCPKT_DOSTOP; 280 else 281 tty->ctrl_status |= TIOCPKT_NOSTOP; 282 } 283 if (extproc) 284 tty->ctrl_status |= TIOCPKT_IOCTL; 285 spin_unlock_irq(&tty->ctrl_lock); 286 wake_up_interruptible(&tty->link->read_wait); 287 } 288 } 289 290 tty->termios.c_cflag &= ~(CSIZE | PARENB); 291 tty->termios.c_cflag |= (CS8 | CREAD); 292 } 293 294 /** 295 * pty_do_resize - resize event 296 * @tty: tty being resized 297 * @ws: window size being set. 298 * 299 * Update the termios variables and send the necessary signals to 300 * peform a terminal resize correctly 301 */ 302 303 static int pty_resize(struct tty_struct *tty, struct winsize *ws) 304 { 305 struct pid *pgrp, *rpgrp; 306 struct tty_struct *pty = tty->link; 307 308 /* For a PTY we need to lock the tty side */ 309 mutex_lock(&tty->winsize_mutex); 310 if (!memcmp(ws, &tty->winsize, sizeof(*ws))) 311 goto done; 312 313 /* Signal the foreground process group of both ptys */ 314 pgrp = tty_get_pgrp(tty); 315 rpgrp = tty_get_pgrp(pty); 316 317 if (pgrp) 318 kill_pgrp(pgrp, SIGWINCH, 1); 319 if (rpgrp != pgrp && rpgrp) 320 kill_pgrp(rpgrp, SIGWINCH, 1); 321 322 put_pid(pgrp); 323 put_pid(rpgrp); 324 325 tty->winsize = *ws; 326 pty->winsize = *ws; /* Never used so will go away soon */ 327 done: 328 mutex_unlock(&tty->winsize_mutex); 329 return 0; 330 } 331 332 /** 333 * pty_start - start() handler 334 * pty_stop - stop() handler 335 * @tty: tty being flow-controlled 336 * 337 * Propagates the TIOCPKT status to the master pty. 338 * 339 * NB: only the master pty can be in packet mode so only the slave 340 * needs start()/stop() handlers 341 */ 342 static void pty_start(struct tty_struct *tty) 343 { 344 unsigned long flags; 345 346 if (tty->link && tty->link->packet) { 347 spin_lock_irqsave(&tty->ctrl_lock, flags); 348 tty->ctrl_status &= ~TIOCPKT_STOP; 349 tty->ctrl_status |= TIOCPKT_START; 350 spin_unlock_irqrestore(&tty->ctrl_lock, flags); 351 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); 352 } 353 } 354 355 static void pty_stop(struct tty_struct *tty) 356 { 357 unsigned long flags; 358 359 if (tty->link && tty->link->packet) { 360 spin_lock_irqsave(&tty->ctrl_lock, flags); 361 tty->ctrl_status &= ~TIOCPKT_START; 362 tty->ctrl_status |= TIOCPKT_STOP; 363 spin_unlock_irqrestore(&tty->ctrl_lock, flags); 364 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); 365 } 366 } 367 368 /** 369 * pty_common_install - set up the pty pair 370 * @driver: the pty driver 371 * @tty: the tty being instantiated 372 * @legacy: true if this is BSD style 373 * 374 * Perform the initial set up for the tty/pty pair. Called from the 375 * tty layer when the port is first opened. 376 * 377 * Locking: the caller must hold the tty_mutex 378 */ 379 static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, 380 bool legacy) 381 { 382 struct tty_struct *o_tty; 383 struct tty_port *ports[2]; 384 int idx = tty->index; 385 int retval = -ENOMEM; 386 387 /* Opening the slave first has always returned -EIO */ 388 if (driver->subtype != PTY_TYPE_MASTER) 389 return -EIO; 390 391 ports[0] = kmalloc(sizeof **ports, GFP_KERNEL); 392 ports[1] = kmalloc(sizeof **ports, GFP_KERNEL); 393 if (!ports[0] || !ports[1]) 394 goto err; 395 if (!try_module_get(driver->other->owner)) { 396 /* This cannot in fact currently happen */ 397 goto err; 398 } 399 o_tty = alloc_tty_struct(driver->other, idx); 400 if (!o_tty) 401 goto err_put_module; 402 403 tty_set_lock_subclass(o_tty); 404 lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE); 405 406 if (legacy) { 407 /* We always use new tty termios data so we can do this 408 the easy way .. */ 409 retval = tty_init_termios(tty); 410 if (retval) 411 goto err_deinit_tty; 412 413 retval = tty_init_termios(o_tty); 414 if (retval) 415 goto err_free_termios; 416 417 driver->other->ttys[idx] = o_tty; 418 driver->ttys[idx] = tty; 419 } else { 420 memset(&tty->termios_locked, 0, sizeof(tty->termios_locked)); 421 tty->termios = driver->init_termios; 422 memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked)); 423 o_tty->termios = driver->other->init_termios; 424 } 425 426 /* 427 * Everything allocated ... set up the o_tty structure. 428 */ 429 tty_driver_kref_get(driver->other); 430 /* Establish the links in both directions */ 431 tty->link = o_tty; 432 o_tty->link = tty; 433 tty_port_init(ports[0]); 434 tty_port_init(ports[1]); 435 tty_buffer_set_limit(ports[0], 8192); 436 tty_buffer_set_limit(ports[1], 8192); 437 o_tty->port = ports[0]; 438 tty->port = ports[1]; 439 o_tty->port->itty = o_tty; 440 441 tty_buffer_set_lock_subclass(o_tty->port); 442 443 tty_driver_kref_get(driver); 444 tty->count++; 445 o_tty->count++; 446 return 0; 447 err_free_termios: 448 if (legacy) 449 tty_free_termios(tty); 450 err_deinit_tty: 451 deinitialize_tty_struct(o_tty); 452 free_tty_struct(o_tty); 453 err_put_module: 454 module_put(driver->other->owner); 455 err: 456 kfree(ports[0]); 457 kfree(ports[1]); 458 return retval; 459 } 460 461 static void pty_cleanup(struct tty_struct *tty) 462 { 463 tty_port_put(tty->port); 464 } 465 466 /* Traditional BSD devices */ 467 #ifdef CONFIG_LEGACY_PTYS 468 469 static int pty_install(struct tty_driver *driver, struct tty_struct *tty) 470 { 471 return pty_common_install(driver, tty, true); 472 } 473 474 static void pty_remove(struct tty_driver *driver, struct tty_struct *tty) 475 { 476 struct tty_struct *pair = tty->link; 477 driver->ttys[tty->index] = NULL; 478 if (pair) 479 pair->driver->ttys[pair->index] = NULL; 480 } 481 482 static int pty_bsd_ioctl(struct tty_struct *tty, 483 unsigned int cmd, unsigned long arg) 484 { 485 switch (cmd) { 486 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ 487 return pty_set_lock(tty, (int __user *) arg); 488 case TIOCGPTLCK: /* Get PT Lock status */ 489 return pty_get_lock(tty, (int __user *)arg); 490 case TIOCPKT: /* Set PT packet mode */ 491 return pty_set_pktmode(tty, (int __user *)arg); 492 case TIOCGPKT: /* Get PT packet mode */ 493 return pty_get_pktmode(tty, (int __user *)arg); 494 case TIOCSIG: /* Send signal to other side of pty */ 495 return pty_signal(tty, (int) arg); 496 case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */ 497 return -EINVAL; 498 } 499 return -ENOIOCTLCMD; 500 } 501 502 static int legacy_count = CONFIG_LEGACY_PTY_COUNT; 503 /* 504 * not really modular, but the easiest way to keep compat with existing 505 * bootargs behaviour is to continue using module_param here. 506 */ 507 module_param(legacy_count, int, 0); 508 509 /* 510 * The master side of a pty can do TIOCSPTLCK and thus 511 * has pty_bsd_ioctl. 512 */ 513 static const struct tty_operations master_pty_ops_bsd = { 514 .install = pty_install, 515 .open = pty_open, 516 .close = pty_close, 517 .write = pty_write, 518 .write_room = pty_write_room, 519 .flush_buffer = pty_flush_buffer, 520 .chars_in_buffer = pty_chars_in_buffer, 521 .unthrottle = pty_unthrottle, 522 .ioctl = pty_bsd_ioctl, 523 .cleanup = pty_cleanup, 524 .resize = pty_resize, 525 .remove = pty_remove 526 }; 527 528 static const struct tty_operations slave_pty_ops_bsd = { 529 .install = pty_install, 530 .open = pty_open, 531 .close = pty_close, 532 .write = pty_write, 533 .write_room = pty_write_room, 534 .flush_buffer = pty_flush_buffer, 535 .chars_in_buffer = pty_chars_in_buffer, 536 .unthrottle = pty_unthrottle, 537 .set_termios = pty_set_termios, 538 .cleanup = pty_cleanup, 539 .resize = pty_resize, 540 .start = pty_start, 541 .stop = pty_stop, 542 .remove = pty_remove 543 }; 544 545 static void __init legacy_pty_init(void) 546 { 547 struct tty_driver *pty_driver, *pty_slave_driver; 548 549 if (legacy_count <= 0) 550 return; 551 552 pty_driver = tty_alloc_driver(legacy_count, 553 TTY_DRIVER_RESET_TERMIOS | 554 TTY_DRIVER_REAL_RAW | 555 TTY_DRIVER_DYNAMIC_ALLOC); 556 if (IS_ERR(pty_driver)) 557 panic("Couldn't allocate pty driver"); 558 559 pty_slave_driver = tty_alloc_driver(legacy_count, 560 TTY_DRIVER_RESET_TERMIOS | 561 TTY_DRIVER_REAL_RAW | 562 TTY_DRIVER_DYNAMIC_ALLOC); 563 if (IS_ERR(pty_slave_driver)) 564 panic("Couldn't allocate pty slave driver"); 565 566 pty_driver->driver_name = "pty_master"; 567 pty_driver->name = "pty"; 568 pty_driver->major = PTY_MASTER_MAJOR; 569 pty_driver->minor_start = 0; 570 pty_driver->type = TTY_DRIVER_TYPE_PTY; 571 pty_driver->subtype = PTY_TYPE_MASTER; 572 pty_driver->init_termios = tty_std_termios; 573 pty_driver->init_termios.c_iflag = 0; 574 pty_driver->init_termios.c_oflag = 0; 575 pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 576 pty_driver->init_termios.c_lflag = 0; 577 pty_driver->init_termios.c_ispeed = 38400; 578 pty_driver->init_termios.c_ospeed = 38400; 579 pty_driver->other = pty_slave_driver; 580 tty_set_operations(pty_driver, &master_pty_ops_bsd); 581 582 pty_slave_driver->driver_name = "pty_slave"; 583 pty_slave_driver->name = "ttyp"; 584 pty_slave_driver->major = PTY_SLAVE_MAJOR; 585 pty_slave_driver->minor_start = 0; 586 pty_slave_driver->type = TTY_DRIVER_TYPE_PTY; 587 pty_slave_driver->subtype = PTY_TYPE_SLAVE; 588 pty_slave_driver->init_termios = tty_std_termios; 589 pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 590 pty_slave_driver->init_termios.c_ispeed = 38400; 591 pty_slave_driver->init_termios.c_ospeed = 38400; 592 pty_slave_driver->other = pty_driver; 593 tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd); 594 595 if (tty_register_driver(pty_driver)) 596 panic("Couldn't register pty driver"); 597 if (tty_register_driver(pty_slave_driver)) 598 panic("Couldn't register pty slave driver"); 599 } 600 #else 601 static inline void legacy_pty_init(void) { } 602 #endif 603 604 /* Unix98 devices */ 605 #ifdef CONFIG_UNIX98_PTYS 606 607 static struct cdev ptmx_cdev; 608 609 static int pty_unix98_ioctl(struct tty_struct *tty, 610 unsigned int cmd, unsigned long arg) 611 { 612 switch (cmd) { 613 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ 614 return pty_set_lock(tty, (int __user *)arg); 615 case TIOCGPTLCK: /* Get PT Lock status */ 616 return pty_get_lock(tty, (int __user *)arg); 617 case TIOCPKT: /* Set PT packet mode */ 618 return pty_set_pktmode(tty, (int __user *)arg); 619 case TIOCGPKT: /* Get PT packet mode */ 620 return pty_get_pktmode(tty, (int __user *)arg); 621 case TIOCGPTN: /* Get PT Number */ 622 return put_user(tty->index, (unsigned int __user *)arg); 623 case TIOCSIG: /* Send signal to other side of pty */ 624 return pty_signal(tty, (int) arg); 625 } 626 627 return -ENOIOCTLCMD; 628 } 629 630 /** 631 * ptm_unix98_lookup - find a pty master 632 * @driver: ptm driver 633 * @idx: tty index 634 * 635 * Look up a pty master device. Called under the tty_mutex for now. 636 * This provides our locking. 637 */ 638 639 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, 640 struct inode *ptm_inode, int idx) 641 { 642 /* Master must be open via /dev/ptmx */ 643 return ERR_PTR(-EIO); 644 } 645 646 /** 647 * pts_unix98_lookup - find a pty slave 648 * @driver: pts driver 649 * @idx: tty index 650 * 651 * Look up a pty master device. Called under the tty_mutex for now. 652 * This provides our locking for the tty pointer. 653 */ 654 655 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, 656 struct inode *pts_inode, int idx) 657 { 658 struct tty_struct *tty; 659 660 mutex_lock(&devpts_mutex); 661 tty = devpts_get_priv(pts_inode); 662 mutex_unlock(&devpts_mutex); 663 /* Master must be open before slave */ 664 if (!tty) 665 return ERR_PTR(-EIO); 666 return tty; 667 } 668 669 /* We have no need to install and remove our tty objects as devpts does all 670 the work for us */ 671 672 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) 673 { 674 return pty_common_install(driver, tty, false); 675 } 676 677 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) 678 { 679 } 680 681 /* this is called once with whichever end is closed last */ 682 static void pty_unix98_shutdown(struct tty_struct *tty) 683 { 684 devpts_kill_index(tty->driver_data, tty->index); 685 } 686 687 static const struct tty_operations ptm_unix98_ops = { 688 .lookup = ptm_unix98_lookup, 689 .install = pty_unix98_install, 690 .remove = pty_unix98_remove, 691 .open = pty_open, 692 .close = pty_close, 693 .write = pty_write, 694 .write_room = pty_write_room, 695 .flush_buffer = pty_flush_buffer, 696 .chars_in_buffer = pty_chars_in_buffer, 697 .unthrottle = pty_unthrottle, 698 .ioctl = pty_unix98_ioctl, 699 .resize = pty_resize, 700 .shutdown = pty_unix98_shutdown, 701 .cleanup = pty_cleanup 702 }; 703 704 static const struct tty_operations pty_unix98_ops = { 705 .lookup = pts_unix98_lookup, 706 .install = pty_unix98_install, 707 .remove = pty_unix98_remove, 708 .open = pty_open, 709 .close = pty_close, 710 .write = pty_write, 711 .write_room = pty_write_room, 712 .flush_buffer = pty_flush_buffer, 713 .chars_in_buffer = pty_chars_in_buffer, 714 .unthrottle = pty_unthrottle, 715 .set_termios = pty_set_termios, 716 .start = pty_start, 717 .stop = pty_stop, 718 .shutdown = pty_unix98_shutdown, 719 .cleanup = pty_cleanup, 720 }; 721 722 /** 723 * ptmx_open - open a unix 98 pty master 724 * @inode: inode of device file 725 * @filp: file pointer to tty 726 * 727 * Allocate a unix98 pty master device from the ptmx driver. 728 * 729 * Locking: tty_mutex protects the init_dev work. tty->count should 730 * protect the rest. 731 * allocated_ptys_lock handles the list of free pty numbers 732 */ 733 734 static int ptmx_open(struct inode *inode, struct file *filp) 735 { 736 struct tty_struct *tty; 737 struct inode *slave_inode; 738 int retval; 739 int index; 740 741 nonseekable_open(inode, filp); 742 743 /* We refuse fsnotify events on ptmx, since it's a shared resource */ 744 filp->f_mode |= FMODE_NONOTIFY; 745 746 retval = tty_alloc_file(filp); 747 if (retval) 748 return retval; 749 750 /* find a device that is not in use. */ 751 mutex_lock(&devpts_mutex); 752 index = devpts_new_index(inode); 753 if (index < 0) { 754 retval = index; 755 mutex_unlock(&devpts_mutex); 756 goto err_file; 757 } 758 759 mutex_unlock(&devpts_mutex); 760 761 mutex_lock(&tty_mutex); 762 tty = tty_init_dev(ptm_driver, index); 763 764 if (IS_ERR(tty)) { 765 retval = PTR_ERR(tty); 766 goto out; 767 } 768 769 /* The tty returned here is locked so we can safely 770 drop the mutex */ 771 mutex_unlock(&tty_mutex); 772 773 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ 774 tty->driver_data = inode; 775 776 tty_add_file(tty, filp); 777 778 slave_inode = devpts_pty_new(inode, 779 MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index, 780 tty->link); 781 if (IS_ERR(slave_inode)) { 782 retval = PTR_ERR(slave_inode); 783 goto err_release; 784 } 785 tty->link->driver_data = slave_inode; 786 787 retval = ptm_driver->ops->open(tty, filp); 788 if (retval) 789 goto err_release; 790 791 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count); 792 793 tty_unlock(tty); 794 return 0; 795 err_release: 796 tty_unlock(tty); 797 tty_release(inode, filp); 798 return retval; 799 out: 800 mutex_unlock(&tty_mutex); 801 devpts_kill_index(inode, index); 802 err_file: 803 tty_free_file(filp); 804 return retval; 805 } 806 807 static struct file_operations ptmx_fops; 808 809 static void __init unix98_pty_init(void) 810 { 811 ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, 812 TTY_DRIVER_RESET_TERMIOS | 813 TTY_DRIVER_REAL_RAW | 814 TTY_DRIVER_DYNAMIC_DEV | 815 TTY_DRIVER_DEVPTS_MEM | 816 TTY_DRIVER_DYNAMIC_ALLOC); 817 if (IS_ERR(ptm_driver)) 818 panic("Couldn't allocate Unix98 ptm driver"); 819 pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, 820 TTY_DRIVER_RESET_TERMIOS | 821 TTY_DRIVER_REAL_RAW | 822 TTY_DRIVER_DYNAMIC_DEV | 823 TTY_DRIVER_DEVPTS_MEM | 824 TTY_DRIVER_DYNAMIC_ALLOC); 825 if (IS_ERR(pts_driver)) 826 panic("Couldn't allocate Unix98 pts driver"); 827 828 ptm_driver->driver_name = "pty_master"; 829 ptm_driver->name = "ptm"; 830 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR; 831 ptm_driver->minor_start = 0; 832 ptm_driver->type = TTY_DRIVER_TYPE_PTY; 833 ptm_driver->subtype = PTY_TYPE_MASTER; 834 ptm_driver->init_termios = tty_std_termios; 835 ptm_driver->init_termios.c_iflag = 0; 836 ptm_driver->init_termios.c_oflag = 0; 837 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 838 ptm_driver->init_termios.c_lflag = 0; 839 ptm_driver->init_termios.c_ispeed = 38400; 840 ptm_driver->init_termios.c_ospeed = 38400; 841 ptm_driver->other = pts_driver; 842 tty_set_operations(ptm_driver, &ptm_unix98_ops); 843 844 pts_driver->driver_name = "pty_slave"; 845 pts_driver->name = "pts"; 846 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR; 847 pts_driver->minor_start = 0; 848 pts_driver->type = TTY_DRIVER_TYPE_PTY; 849 pts_driver->subtype = PTY_TYPE_SLAVE; 850 pts_driver->init_termios = tty_std_termios; 851 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 852 pts_driver->init_termios.c_ispeed = 38400; 853 pts_driver->init_termios.c_ospeed = 38400; 854 pts_driver->other = ptm_driver; 855 tty_set_operations(pts_driver, &pty_unix98_ops); 856 857 if (tty_register_driver(ptm_driver)) 858 panic("Couldn't register Unix98 ptm driver"); 859 if (tty_register_driver(pts_driver)) 860 panic("Couldn't register Unix98 pts driver"); 861 862 /* Now create the /dev/ptmx special device */ 863 tty_default_fops(&ptmx_fops); 864 ptmx_fops.open = ptmx_open; 865 866 cdev_init(&ptmx_cdev, &ptmx_fops); 867 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || 868 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) 869 panic("Couldn't register /dev/ptmx driver"); 870 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); 871 } 872 873 #else 874 static inline void unix98_pty_init(void) { } 875 #endif 876 877 static int __init pty_init(void) 878 { 879 legacy_pty_init(); 880 unix98_pty_init(); 881 return 0; 882 } 883 device_initcall(pty_init); 884