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 #undef TTY_DEBUG_HANGUP 30 #ifdef TTY_DEBUG_HANGUP 31 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args) 32 #else 33 # define tty_debug_hangup(tty, f, args...) do {} while (0) 34 #endif 35 36 #ifdef CONFIG_UNIX98_PTYS 37 static struct tty_driver *ptm_driver; 38 static struct tty_driver *pts_driver; 39 static DEFINE_MUTEX(devpts_mutex); 40 #endif 41 42 static void pty_close(struct tty_struct *tty, struct file *filp) 43 { 44 BUG_ON(!tty); 45 if (tty->driver->subtype == PTY_TYPE_MASTER) 46 WARN_ON(tty->count > 1); 47 else { 48 if (test_bit(TTY_IO_ERROR, &tty->flags)) 49 return; 50 if (tty->count > 2) 51 return; 52 } 53 set_bit(TTY_IO_ERROR, &tty->flags); 54 wake_up_interruptible(&tty->read_wait); 55 wake_up_interruptible(&tty->write_wait); 56 spin_lock_irq(&tty->ctrl_lock); 57 tty->packet = 0; 58 spin_unlock_irq(&tty->ctrl_lock); 59 /* Review - krefs on tty_link ?? */ 60 if (!tty->link) 61 return; 62 set_bit(TTY_OTHER_CLOSED, &tty->link->flags); 63 tty_flip_buffer_push(tty->link->port); 64 wake_up_interruptible(&tty->link->write_wait); 65 if (tty->driver->subtype == PTY_TYPE_MASTER) { 66 set_bit(TTY_OTHER_CLOSED, &tty->flags); 67 #ifdef CONFIG_UNIX98_PTYS 68 if (tty->driver == ptm_driver) { 69 mutex_lock(&devpts_mutex); 70 if (tty->link->driver_data) 71 devpts_pty_kill(tty->link->driver_data); 72 mutex_unlock(&devpts_mutex); 73 } 74 #endif 75 tty_vhangup(tty->link); 76 } 77 } 78 79 /* 80 * The unthrottle routine is called by the line discipline to signal 81 * that it can receive more characters. For PTY's, the TTY_THROTTLED 82 * flag is always set, to force the line discipline to always call the 83 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE 84 * characters in the queue. This is necessary since each time this 85 * happens, we need to wake up any sleeping processes that could be 86 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent() 87 * for the pty buffer to be drained. 88 */ 89 static void pty_unthrottle(struct tty_struct *tty) 90 { 91 tty_wakeup(tty->link); 92 set_bit(TTY_THROTTLED, &tty->flags); 93 } 94 95 /** 96 * pty_write - write to a pty 97 * @tty: the tty we write from 98 * @buf: kernel buffer of data 99 * @count: bytes to write 100 * 101 * Our "hardware" write method. Data is coming from the ldisc which 102 * may be in a non sleeping state. We simply throw this at the other 103 * end of the link as if we were an IRQ handler receiving stuff for 104 * the other side of the pty/tty pair. 105 */ 106 107 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c) 108 { 109 struct tty_struct *to = tty->link; 110 111 if (tty->stopped) 112 return 0; 113 114 if (c > 0) { 115 /* Stuff the data into the input queue of the other end */ 116 c = tty_insert_flip_string(to->port, buf, c); 117 /* And shovel */ 118 if (c) 119 tty_flip_buffer_push(to->port); 120 } 121 return c; 122 } 123 124 /** 125 * pty_write_room - write space 126 * @tty: tty we are writing from 127 * 128 * Report how many bytes the ldisc can send into the queue for 129 * the other device. 130 */ 131 132 static int pty_write_room(struct tty_struct *tty) 133 { 134 if (tty->stopped) 135 return 0; 136 return tty_buffer_space_avail(tty->link->port); 137 } 138 139 /** 140 * pty_chars_in_buffer - characters currently in our tx queue 141 * @tty: our tty 142 * 143 * Report how much we have in the transmit queue. As everything is 144 * instantly at the other end this is easy to implement. 145 */ 146 147 static int pty_chars_in_buffer(struct tty_struct *tty) 148 { 149 return 0; 150 } 151 152 /* Set the lock flag on a pty */ 153 static int pty_set_lock(struct tty_struct *tty, int __user *arg) 154 { 155 int val; 156 if (get_user(val, arg)) 157 return -EFAULT; 158 if (val) 159 set_bit(TTY_PTY_LOCK, &tty->flags); 160 else 161 clear_bit(TTY_PTY_LOCK, &tty->flags); 162 return 0; 163 } 164 165 static int pty_get_lock(struct tty_struct *tty, int __user *arg) 166 { 167 int locked = test_bit(TTY_PTY_LOCK, &tty->flags); 168 return put_user(locked, arg); 169 } 170 171 /* Set the packet mode on a pty */ 172 static int pty_set_pktmode(struct tty_struct *tty, int __user *arg) 173 { 174 int pktmode; 175 176 if (get_user(pktmode, arg)) 177 return -EFAULT; 178 179 spin_lock_irq(&tty->ctrl_lock); 180 if (pktmode) { 181 if (!tty->packet) { 182 tty->link->ctrl_status = 0; 183 smp_mb(); 184 tty->packet = 1; 185 } 186 } else 187 tty->packet = 0; 188 spin_unlock_irq(&tty->ctrl_lock); 189 190 return 0; 191 } 192 193 /* Get the packet mode of a pty */ 194 static int pty_get_pktmode(struct tty_struct *tty, int __user *arg) 195 { 196 int pktmode = tty->packet; 197 return put_user(pktmode, arg); 198 } 199 200 /* Send a signal to the slave */ 201 static int pty_signal(struct tty_struct *tty, int sig) 202 { 203 struct pid *pgrp; 204 205 if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP) 206 return -EINVAL; 207 208 if (tty->link) { 209 pgrp = tty_get_pgrp(tty->link); 210 if (pgrp) 211 kill_pgrp(pgrp, sig, 1); 212 put_pid(pgrp); 213 } 214 return 0; 215 } 216 217 static void pty_flush_buffer(struct tty_struct *tty) 218 { 219 struct tty_struct *to = tty->link; 220 struct tty_ldisc *ld; 221 222 if (!to) 223 return; 224 225 ld = tty_ldisc_ref(to); 226 tty_buffer_flush(to, ld); 227 if (ld) 228 tty_ldisc_deref(ld); 229 230 if (to->packet) { 231 spin_lock_irq(&tty->ctrl_lock); 232 tty->ctrl_status |= TIOCPKT_FLUSHWRITE; 233 wake_up_interruptible(&to->read_wait); 234 spin_unlock_irq(&tty->ctrl_lock); 235 } 236 } 237 238 static int pty_open(struct tty_struct *tty, struct file *filp) 239 { 240 if (!tty || !tty->link) 241 return -ENODEV; 242 243 if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) 244 goto out; 245 if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) 246 goto out; 247 if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1) 248 goto out; 249 250 clear_bit(TTY_IO_ERROR, &tty->flags); 251 /* TTY_OTHER_CLOSED must be cleared before TTY_OTHER_DONE */ 252 clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); 253 clear_bit(TTY_OTHER_DONE, &tty->link->flags); 254 set_bit(TTY_THROTTLED, &tty->flags); 255 return 0; 256 257 out: 258 set_bit(TTY_IO_ERROR, &tty->flags); 259 return -EIO; 260 } 261 262 static void pty_set_termios(struct tty_struct *tty, 263 struct ktermios *old_termios) 264 { 265 /* See if packet mode change of state. */ 266 if (tty->link && tty->link->packet) { 267 int extproc = (old_termios->c_lflag & EXTPROC) | 268 (tty->termios.c_lflag & EXTPROC); 269 int old_flow = ((old_termios->c_iflag & IXON) && 270 (old_termios->c_cc[VSTOP] == '\023') && 271 (old_termios->c_cc[VSTART] == '\021')); 272 int new_flow = (I_IXON(tty) && 273 STOP_CHAR(tty) == '\023' && 274 START_CHAR(tty) == '\021'); 275 if ((old_flow != new_flow) || extproc) { 276 spin_lock_irq(&tty->ctrl_lock); 277 if (old_flow != new_flow) { 278 tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); 279 if (new_flow) 280 tty->ctrl_status |= TIOCPKT_DOSTOP; 281 else 282 tty->ctrl_status |= TIOCPKT_NOSTOP; 283 } 284 if (extproc) 285 tty->ctrl_status |= TIOCPKT_IOCTL; 286 spin_unlock_irq(&tty->ctrl_lock); 287 wake_up_interruptible(&tty->link->read_wait); 288 } 289 } 290 291 tty->termios.c_cflag &= ~(CSIZE | PARENB); 292 tty->termios.c_cflag |= (CS8 | CREAD); 293 } 294 295 /** 296 * pty_do_resize - resize event 297 * @tty: tty being resized 298 * @ws: window size being set. 299 * 300 * Update the termios variables and send the necessary signals to 301 * peform a terminal resize correctly 302 */ 303 304 static int pty_resize(struct tty_struct *tty, struct winsize *ws) 305 { 306 struct pid *pgrp, *rpgrp; 307 struct tty_struct *pty = tty->link; 308 309 /* For a PTY we need to lock the tty side */ 310 mutex_lock(&tty->winsize_mutex); 311 if (!memcmp(ws, &tty->winsize, sizeof(*ws))) 312 goto done; 313 314 /* Signal the foreground process group of both ptys */ 315 pgrp = tty_get_pgrp(tty); 316 rpgrp = tty_get_pgrp(pty); 317 318 if (pgrp) 319 kill_pgrp(pgrp, SIGWINCH, 1); 320 if (rpgrp != pgrp && rpgrp) 321 kill_pgrp(rpgrp, SIGWINCH, 1); 322 323 put_pid(pgrp); 324 put_pid(rpgrp); 325 326 tty->winsize = *ws; 327 pty->winsize = *ws; /* Never used so will go away soon */ 328 done: 329 mutex_unlock(&tty->winsize_mutex); 330 return 0; 331 } 332 333 /** 334 * pty_start - start() handler 335 * pty_stop - stop() handler 336 * @tty: tty being flow-controlled 337 * 338 * Propagates the TIOCPKT status to the master pty. 339 * 340 * NB: only the master pty can be in packet mode so only the slave 341 * needs start()/stop() handlers 342 */ 343 static void pty_start(struct tty_struct *tty) 344 { 345 unsigned long flags; 346 347 if (tty->link && tty->link->packet) { 348 spin_lock_irqsave(&tty->ctrl_lock, flags); 349 tty->ctrl_status &= ~TIOCPKT_STOP; 350 tty->ctrl_status |= TIOCPKT_START; 351 spin_unlock_irqrestore(&tty->ctrl_lock, flags); 352 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); 353 } 354 } 355 356 static void pty_stop(struct tty_struct *tty) 357 { 358 unsigned long flags; 359 360 if (tty->link && tty->link->packet) { 361 spin_lock_irqsave(&tty->ctrl_lock, flags); 362 tty->ctrl_status &= ~TIOCPKT_START; 363 tty->ctrl_status |= TIOCPKT_STOP; 364 spin_unlock_irqrestore(&tty->ctrl_lock, flags); 365 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); 366 } 367 } 368 369 /** 370 * pty_common_install - set up the pty pair 371 * @driver: the pty driver 372 * @tty: the tty being instantiated 373 * @legacy: true if this is BSD style 374 * 375 * Perform the initial set up for the tty/pty pair. Called from the 376 * tty layer when the port is first opened. 377 * 378 * Locking: the caller must hold the tty_mutex 379 */ 380 static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, 381 bool legacy) 382 { 383 struct tty_struct *o_tty; 384 struct tty_port *ports[2]; 385 int idx = tty->index; 386 int retval = -ENOMEM; 387 388 /* Opening the slave first has always returned -EIO */ 389 if (driver->subtype != PTY_TYPE_MASTER) 390 return -EIO; 391 392 ports[0] = kmalloc(sizeof **ports, GFP_KERNEL); 393 ports[1] = kmalloc(sizeof **ports, GFP_KERNEL); 394 if (!ports[0] || !ports[1]) 395 goto err; 396 if (!try_module_get(driver->other->owner)) { 397 /* This cannot in fact currently happen */ 398 goto err; 399 } 400 o_tty = alloc_tty_struct(driver->other, idx); 401 if (!o_tty) 402 goto err_put_module; 403 404 tty_set_lock_subclass(o_tty); 405 lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE); 406 407 if (legacy) { 408 /* We always use new tty termios data so we can do this 409 the easy way .. */ 410 retval = tty_init_termios(tty); 411 if (retval) 412 goto err_deinit_tty; 413 414 retval = tty_init_termios(o_tty); 415 if (retval) 416 goto err_free_termios; 417 418 driver->other->ttys[idx] = o_tty; 419 driver->ttys[idx] = tty; 420 } else { 421 memset(&tty->termios_locked, 0, sizeof(tty->termios_locked)); 422 tty->termios = driver->init_termios; 423 memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked)); 424 o_tty->termios = driver->other->init_termios; 425 } 426 427 /* 428 * Everything allocated ... set up the o_tty structure. 429 */ 430 tty_driver_kref_get(driver->other); 431 /* Establish the links in both directions */ 432 tty->link = o_tty; 433 o_tty->link = tty; 434 tty_port_init(ports[0]); 435 tty_port_init(ports[1]); 436 tty_buffer_set_limit(ports[0], 8192); 437 tty_buffer_set_limit(ports[1], 8192); 438 o_tty->port = ports[0]; 439 tty->port = ports[1]; 440 o_tty->port->itty = o_tty; 441 442 tty_buffer_set_lock_subclass(o_tty->port); 443 444 tty_driver_kref_get(driver); 445 tty->count++; 446 o_tty->count++; 447 return 0; 448 err_free_termios: 449 if (legacy) 450 tty_free_termios(tty); 451 err_deinit_tty: 452 deinitialize_tty_struct(o_tty); 453 free_tty_struct(o_tty); 454 err_put_module: 455 module_put(driver->other->owner); 456 err: 457 kfree(ports[0]); 458 kfree(ports[1]); 459 return retval; 460 } 461 462 static void pty_cleanup(struct tty_struct *tty) 463 { 464 tty_port_put(tty->port); 465 } 466 467 /* Traditional BSD devices */ 468 #ifdef CONFIG_LEGACY_PTYS 469 470 static int pty_install(struct tty_driver *driver, struct tty_struct *tty) 471 { 472 return pty_common_install(driver, tty, true); 473 } 474 475 static void pty_remove(struct tty_driver *driver, struct tty_struct *tty) 476 { 477 struct tty_struct *pair = tty->link; 478 driver->ttys[tty->index] = NULL; 479 if (pair) 480 pair->driver->ttys[pair->index] = NULL; 481 } 482 483 static int pty_bsd_ioctl(struct tty_struct *tty, 484 unsigned int cmd, unsigned long arg) 485 { 486 switch (cmd) { 487 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ 488 return pty_set_lock(tty, (int __user *) arg); 489 case TIOCGPTLCK: /* Get PT Lock status */ 490 return pty_get_lock(tty, (int __user *)arg); 491 case TIOCPKT: /* Set PT packet mode */ 492 return pty_set_pktmode(tty, (int __user *)arg); 493 case TIOCGPKT: /* Get PT packet mode */ 494 return pty_get_pktmode(tty, (int __user *)arg); 495 case TIOCSIG: /* Send signal to other side of pty */ 496 return pty_signal(tty, (int) arg); 497 case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */ 498 return -EINVAL; 499 } 500 return -ENOIOCTLCMD; 501 } 502 503 static int legacy_count = CONFIG_LEGACY_PTY_COUNT; 504 module_param(legacy_count, int, 0); 505 506 /* 507 * The master side of a pty can do TIOCSPTLCK and thus 508 * has pty_bsd_ioctl. 509 */ 510 static const struct tty_operations master_pty_ops_bsd = { 511 .install = pty_install, 512 .open = pty_open, 513 .close = pty_close, 514 .write = pty_write, 515 .write_room = pty_write_room, 516 .flush_buffer = pty_flush_buffer, 517 .chars_in_buffer = pty_chars_in_buffer, 518 .unthrottle = pty_unthrottle, 519 .ioctl = pty_bsd_ioctl, 520 .cleanup = pty_cleanup, 521 .resize = pty_resize, 522 .remove = pty_remove 523 }; 524 525 static const struct tty_operations slave_pty_ops_bsd = { 526 .install = pty_install, 527 .open = pty_open, 528 .close = pty_close, 529 .write = pty_write, 530 .write_room = pty_write_room, 531 .flush_buffer = pty_flush_buffer, 532 .chars_in_buffer = pty_chars_in_buffer, 533 .unthrottle = pty_unthrottle, 534 .set_termios = pty_set_termios, 535 .cleanup = pty_cleanup, 536 .resize = pty_resize, 537 .start = pty_start, 538 .stop = pty_stop, 539 .remove = pty_remove 540 }; 541 542 static void __init legacy_pty_init(void) 543 { 544 struct tty_driver *pty_driver, *pty_slave_driver; 545 546 if (legacy_count <= 0) 547 return; 548 549 pty_driver = tty_alloc_driver(legacy_count, 550 TTY_DRIVER_RESET_TERMIOS | 551 TTY_DRIVER_REAL_RAW | 552 TTY_DRIVER_DYNAMIC_ALLOC); 553 if (IS_ERR(pty_driver)) 554 panic("Couldn't allocate pty driver"); 555 556 pty_slave_driver = tty_alloc_driver(legacy_count, 557 TTY_DRIVER_RESET_TERMIOS | 558 TTY_DRIVER_REAL_RAW | 559 TTY_DRIVER_DYNAMIC_ALLOC); 560 if (IS_ERR(pty_slave_driver)) 561 panic("Couldn't allocate pty slave driver"); 562 563 pty_driver->driver_name = "pty_master"; 564 pty_driver->name = "pty"; 565 pty_driver->major = PTY_MASTER_MAJOR; 566 pty_driver->minor_start = 0; 567 pty_driver->type = TTY_DRIVER_TYPE_PTY; 568 pty_driver->subtype = PTY_TYPE_MASTER; 569 pty_driver->init_termios = tty_std_termios; 570 pty_driver->init_termios.c_iflag = 0; 571 pty_driver->init_termios.c_oflag = 0; 572 pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 573 pty_driver->init_termios.c_lflag = 0; 574 pty_driver->init_termios.c_ispeed = 38400; 575 pty_driver->init_termios.c_ospeed = 38400; 576 pty_driver->other = pty_slave_driver; 577 tty_set_operations(pty_driver, &master_pty_ops_bsd); 578 579 pty_slave_driver->driver_name = "pty_slave"; 580 pty_slave_driver->name = "ttyp"; 581 pty_slave_driver->major = PTY_SLAVE_MAJOR; 582 pty_slave_driver->minor_start = 0; 583 pty_slave_driver->type = TTY_DRIVER_TYPE_PTY; 584 pty_slave_driver->subtype = PTY_TYPE_SLAVE; 585 pty_slave_driver->init_termios = tty_std_termios; 586 pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 587 pty_slave_driver->init_termios.c_ispeed = 38400; 588 pty_slave_driver->init_termios.c_ospeed = 38400; 589 pty_slave_driver->other = pty_driver; 590 tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd); 591 592 if (tty_register_driver(pty_driver)) 593 panic("Couldn't register pty driver"); 594 if (tty_register_driver(pty_slave_driver)) 595 panic("Couldn't register pty slave driver"); 596 } 597 #else 598 static inline void legacy_pty_init(void) { } 599 #endif 600 601 /* Unix98 devices */ 602 #ifdef CONFIG_UNIX98_PTYS 603 604 static struct cdev ptmx_cdev; 605 606 static int pty_unix98_ioctl(struct tty_struct *tty, 607 unsigned int cmd, unsigned long arg) 608 { 609 switch (cmd) { 610 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ 611 return pty_set_lock(tty, (int __user *)arg); 612 case TIOCGPTLCK: /* Get PT Lock status */ 613 return pty_get_lock(tty, (int __user *)arg); 614 case TIOCPKT: /* Set PT packet mode */ 615 return pty_set_pktmode(tty, (int __user *)arg); 616 case TIOCGPKT: /* Get PT packet mode */ 617 return pty_get_pktmode(tty, (int __user *)arg); 618 case TIOCGPTN: /* Get PT Number */ 619 return put_user(tty->index, (unsigned int __user *)arg); 620 case TIOCSIG: /* Send signal to other side of pty */ 621 return pty_signal(tty, (int) arg); 622 } 623 624 return -ENOIOCTLCMD; 625 } 626 627 /** 628 * ptm_unix98_lookup - find a pty master 629 * @driver: ptm driver 630 * @idx: tty index 631 * 632 * Look up a pty master device. Called under the tty_mutex for now. 633 * This provides our locking. 634 */ 635 636 static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, 637 struct inode *ptm_inode, int idx) 638 { 639 /* Master must be open via /dev/ptmx */ 640 return ERR_PTR(-EIO); 641 } 642 643 /** 644 * pts_unix98_lookup - find a pty slave 645 * @driver: pts driver 646 * @idx: tty index 647 * 648 * Look up a pty master device. Called under the tty_mutex for now. 649 * This provides our locking for the tty pointer. 650 */ 651 652 static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, 653 struct inode *pts_inode, int idx) 654 { 655 struct tty_struct *tty; 656 657 mutex_lock(&devpts_mutex); 658 tty = devpts_get_priv(pts_inode); 659 mutex_unlock(&devpts_mutex); 660 /* Master must be open before slave */ 661 if (!tty) 662 return ERR_PTR(-EIO); 663 return tty; 664 } 665 666 /* We have no need to install and remove our tty objects as devpts does all 667 the work for us */ 668 669 static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) 670 { 671 return pty_common_install(driver, tty, false); 672 } 673 674 static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) 675 { 676 } 677 678 /* this is called once with whichever end is closed last */ 679 static void pty_unix98_shutdown(struct tty_struct *tty) 680 { 681 devpts_kill_index(tty->driver_data, tty->index); 682 } 683 684 static const struct tty_operations ptm_unix98_ops = { 685 .lookup = ptm_unix98_lookup, 686 .install = pty_unix98_install, 687 .remove = pty_unix98_remove, 688 .open = pty_open, 689 .close = pty_close, 690 .write = pty_write, 691 .write_room = pty_write_room, 692 .flush_buffer = pty_flush_buffer, 693 .chars_in_buffer = pty_chars_in_buffer, 694 .unthrottle = pty_unthrottle, 695 .ioctl = pty_unix98_ioctl, 696 .resize = pty_resize, 697 .shutdown = pty_unix98_shutdown, 698 .cleanup = pty_cleanup 699 }; 700 701 static const struct tty_operations pty_unix98_ops = { 702 .lookup = pts_unix98_lookup, 703 .install = pty_unix98_install, 704 .remove = pty_unix98_remove, 705 .open = pty_open, 706 .close = pty_close, 707 .write = pty_write, 708 .write_room = pty_write_room, 709 .flush_buffer = pty_flush_buffer, 710 .chars_in_buffer = pty_chars_in_buffer, 711 .unthrottle = pty_unthrottle, 712 .set_termios = pty_set_termios, 713 .start = pty_start, 714 .stop = pty_stop, 715 .shutdown = pty_unix98_shutdown, 716 .cleanup = pty_cleanup, 717 }; 718 719 /** 720 * ptmx_open - open a unix 98 pty master 721 * @inode: inode of device file 722 * @filp: file pointer to tty 723 * 724 * Allocate a unix98 pty master device from the ptmx driver. 725 * 726 * Locking: tty_mutex protects the init_dev work. tty->count should 727 * protect the rest. 728 * allocated_ptys_lock handles the list of free pty numbers 729 */ 730 731 static int ptmx_open(struct inode *inode, struct file *filp) 732 { 733 struct tty_struct *tty; 734 struct inode *slave_inode; 735 int retval; 736 int index; 737 738 nonseekable_open(inode, filp); 739 740 /* We refuse fsnotify events on ptmx, since it's a shared resource */ 741 filp->f_mode |= FMODE_NONOTIFY; 742 743 retval = tty_alloc_file(filp); 744 if (retval) 745 return retval; 746 747 /* find a device that is not in use. */ 748 mutex_lock(&devpts_mutex); 749 index = devpts_new_index(inode); 750 if (index < 0) { 751 retval = index; 752 mutex_unlock(&devpts_mutex); 753 goto err_file; 754 } 755 756 mutex_unlock(&devpts_mutex); 757 758 mutex_lock(&tty_mutex); 759 tty = tty_init_dev(ptm_driver, index); 760 761 if (IS_ERR(tty)) { 762 retval = PTR_ERR(tty); 763 goto out; 764 } 765 766 /* The tty returned here is locked so we can safely 767 drop the mutex */ 768 mutex_unlock(&tty_mutex); 769 770 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ 771 tty->driver_data = inode; 772 773 tty_add_file(tty, filp); 774 775 slave_inode = devpts_pty_new(inode, 776 MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index, 777 tty->link); 778 if (IS_ERR(slave_inode)) { 779 retval = PTR_ERR(slave_inode); 780 goto err_release; 781 } 782 tty->link->driver_data = slave_inode; 783 784 retval = ptm_driver->ops->open(tty, filp); 785 if (retval) 786 goto err_release; 787 788 tty_debug_hangup(tty, "(tty count=%d)\n", tty->count); 789 790 tty_unlock(tty); 791 return 0; 792 err_release: 793 tty_unlock(tty); 794 tty_release(inode, filp); 795 return retval; 796 out: 797 mutex_unlock(&tty_mutex); 798 devpts_kill_index(inode, index); 799 err_file: 800 tty_free_file(filp); 801 return retval; 802 } 803 804 static struct file_operations ptmx_fops; 805 806 static void __init unix98_pty_init(void) 807 { 808 ptm_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(ptm_driver)) 815 panic("Couldn't allocate Unix98 ptm driver"); 816 pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, 817 TTY_DRIVER_RESET_TERMIOS | 818 TTY_DRIVER_REAL_RAW | 819 TTY_DRIVER_DYNAMIC_DEV | 820 TTY_DRIVER_DEVPTS_MEM | 821 TTY_DRIVER_DYNAMIC_ALLOC); 822 if (IS_ERR(pts_driver)) 823 panic("Couldn't allocate Unix98 pts driver"); 824 825 ptm_driver->driver_name = "pty_master"; 826 ptm_driver->name = "ptm"; 827 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR; 828 ptm_driver->minor_start = 0; 829 ptm_driver->type = TTY_DRIVER_TYPE_PTY; 830 ptm_driver->subtype = PTY_TYPE_MASTER; 831 ptm_driver->init_termios = tty_std_termios; 832 ptm_driver->init_termios.c_iflag = 0; 833 ptm_driver->init_termios.c_oflag = 0; 834 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 835 ptm_driver->init_termios.c_lflag = 0; 836 ptm_driver->init_termios.c_ispeed = 38400; 837 ptm_driver->init_termios.c_ospeed = 38400; 838 ptm_driver->other = pts_driver; 839 tty_set_operations(ptm_driver, &ptm_unix98_ops); 840 841 pts_driver->driver_name = "pty_slave"; 842 pts_driver->name = "pts"; 843 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR; 844 pts_driver->minor_start = 0; 845 pts_driver->type = TTY_DRIVER_TYPE_PTY; 846 pts_driver->subtype = PTY_TYPE_SLAVE; 847 pts_driver->init_termios = tty_std_termios; 848 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; 849 pts_driver->init_termios.c_ispeed = 38400; 850 pts_driver->init_termios.c_ospeed = 38400; 851 pts_driver->other = ptm_driver; 852 tty_set_operations(pts_driver, &pty_unix98_ops); 853 854 if (tty_register_driver(ptm_driver)) 855 panic("Couldn't register Unix98 ptm driver"); 856 if (tty_register_driver(pts_driver)) 857 panic("Couldn't register Unix98 pts driver"); 858 859 /* Now create the /dev/ptmx special device */ 860 tty_default_fops(&ptmx_fops); 861 ptmx_fops.open = ptmx_open; 862 863 cdev_init(&ptmx_cdev, &ptmx_fops); 864 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || 865 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) 866 panic("Couldn't register /dev/ptmx driver"); 867 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); 868 } 869 870 #else 871 static inline void unix98_pty_init(void) { } 872 #endif 873 874 static int __init pty_init(void) 875 { 876 legacy_pty_init(); 877 unix98_pty_init(); 878 return 0; 879 } 880 module_init(pty_init); 881