1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 1991, 1992 Linus Torvalds 4 */ 5 6 /* 7 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles 8 * or rs-channels. It also implements echoing, cooked mode etc. 9 * 10 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0. 11 * 12 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the 13 * tty_struct and tty_queue structures. Previously there was an array 14 * of 256 tty_struct's which was statically allocated, and the 15 * tty_queue structures were allocated at boot time. Both are now 16 * dynamically allocated only when the tty is open. 17 * 18 * Also restructured routines so that there is more of a separation 19 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and 20 * the low-level tty routines (serial.c, pty.c, console.c). This 21 * makes for cleaner and more compact code. -TYT, 9/17/92 22 * 23 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines 24 * which can be dynamically activated and de-activated by the line 25 * discipline handling modules (like SLIP). 26 * 27 * NOTE: pay no attention to the line discipline code (yet); its 28 * interface is still subject to change in this version... 29 * -- TYT, 1/31/92 30 * 31 * Added functionality to the OPOST tty handling. No delays, but all 32 * other bits should be there. 33 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993. 34 * 35 * Rewrote canonical mode and added more termios flags. 36 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94 37 * 38 * Reorganized FASYNC support so mouse code can share it. 39 * -- ctm@ardi.com, 9Sep95 40 * 41 * New TIOCLINUX variants added. 42 * -- mj@k332.feld.cvut.cz, 19-Nov-95 43 * 44 * Restrict vt switching via ioctl() 45 * -- grif@cs.ucr.edu, 5-Dec-95 46 * 47 * Move console and virtual terminal code to more appropriate files, 48 * implement CONFIG_VT and generalize console device interface. 49 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97 50 * 51 * Rewrote tty_init_dev and tty_release_dev to eliminate races. 52 * -- Bill Hawes <whawes@star.net>, June 97 53 * 54 * Added devfs support. 55 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998 56 * 57 * Added support for a Unix98-style ptmx device. 58 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 59 * 60 * Reduced memory usage for older ARM systems 61 * -- Russell King <rmk@arm.linux.org.uk> 62 * 63 * Move do_SAK() into process context. Less stack use in devfs functions. 64 * alloc_tty_struct() always uses kmalloc() 65 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 66 */ 67 68 #include <linux/types.h> 69 #include <linux/major.h> 70 #include <linux/errno.h> 71 #include <linux/signal.h> 72 #include <linux/fcntl.h> 73 #include <linux/sched/signal.h> 74 #include <linux/sched/task.h> 75 #include <linux/interrupt.h> 76 #include <linux/tty.h> 77 #include <linux/tty_driver.h> 78 #include <linux/tty_flip.h> 79 #include <linux/devpts_fs.h> 80 #include <linux/file.h> 81 #include <linux/fdtable.h> 82 #include <linux/console.h> 83 #include <linux/timer.h> 84 #include <linux/ctype.h> 85 #include <linux/kd.h> 86 #include <linux/mm.h> 87 #include <linux/string.h> 88 #include <linux/slab.h> 89 #include <linux/poll.h> 90 #include <linux/ppp-ioctl.h> 91 #include <linux/proc_fs.h> 92 #include <linux/init.h> 93 #include <linux/module.h> 94 #include <linux/device.h> 95 #include <linux/wait.h> 96 #include <linux/bitops.h> 97 #include <linux/delay.h> 98 #include <linux/seq_file.h> 99 #include <linux/serial.h> 100 #include <linux/ratelimit.h> 101 #include <linux/compat.h> 102 #include <linux/uaccess.h> 103 #include <linux/termios_internal.h> 104 #include <linux/fs.h> 105 106 #include <linux/kbd_kern.h> 107 #include <linux/vt_kern.h> 108 #include <linux/selection.h> 109 110 #include <linux/kmod.h> 111 #include <linux/nsproxy.h> 112 #include "tty.h" 113 114 #undef TTY_DEBUG_HANGUP 115 #ifdef TTY_DEBUG_HANGUP 116 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args) 117 #else 118 # define tty_debug_hangup(tty, f, args...) do { } while (0) 119 #endif 120 121 #define TTY_PARANOIA_CHECK 1 122 #define CHECK_TTY_COUNT 1 123 124 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */ 125 .c_iflag = ICRNL | IXON, 126 .c_oflag = OPOST | ONLCR, 127 .c_cflag = B38400 | CS8 | CREAD | HUPCL, 128 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | 129 ECHOCTL | ECHOKE | IEXTEN, 130 .c_cc = INIT_C_CC, 131 .c_ispeed = 38400, 132 .c_ospeed = 38400, 133 /* .c_line = N_TTY, */ 134 }; 135 EXPORT_SYMBOL(tty_std_termios); 136 137 /* This list gets poked at by procfs and various bits of boot up code. This 138 * could do with some rationalisation such as pulling the tty proc function 139 * into this file. 140 */ 141 142 LIST_HEAD(tty_drivers); /* linked list of tty drivers */ 143 144 /* Mutex to protect creating and releasing a tty */ 145 DEFINE_MUTEX(tty_mutex); 146 147 static ssize_t tty_read(struct kiocb *, struct iov_iter *); 148 static ssize_t tty_write(struct kiocb *, struct iov_iter *); 149 static __poll_t tty_poll(struct file *, poll_table *); 150 static int tty_open(struct inode *, struct file *); 151 #ifdef CONFIG_COMPAT 152 static long tty_compat_ioctl(struct file *file, unsigned int cmd, 153 unsigned long arg); 154 #else 155 #define tty_compat_ioctl NULL 156 #endif 157 static int __tty_fasync(int fd, struct file *filp, int on); 158 static int tty_fasync(int fd, struct file *filp, int on); 159 static void release_tty(struct tty_struct *tty, int idx); 160 161 /** 162 * free_tty_struct - free a disused tty 163 * @tty: tty struct to free 164 * 165 * Free the write buffers, tty queue and tty memory itself. 166 * 167 * Locking: none. Must be called after tty is definitely unused 168 */ 169 static void free_tty_struct(struct tty_struct *tty) 170 { 171 tty_ldisc_deinit(tty); 172 put_device(tty->dev); 173 kvfree(tty->write_buf); 174 kfree(tty); 175 } 176 177 static inline struct tty_struct *file_tty(struct file *file) 178 { 179 return ((struct tty_file_private *)file->private_data)->tty; 180 } 181 182 int tty_alloc_file(struct file *file) 183 { 184 struct tty_file_private *priv; 185 186 priv = kmalloc(sizeof(*priv), GFP_KERNEL); 187 if (!priv) 188 return -ENOMEM; 189 190 file->private_data = priv; 191 192 return 0; 193 } 194 195 /* Associate a new file with the tty structure */ 196 void tty_add_file(struct tty_struct *tty, struct file *file) 197 { 198 struct tty_file_private *priv = file->private_data; 199 200 priv->tty = tty; 201 priv->file = file; 202 203 spin_lock(&tty->files_lock); 204 list_add(&priv->list, &tty->tty_files); 205 spin_unlock(&tty->files_lock); 206 } 207 208 /** 209 * tty_free_file - free file->private_data 210 * @file: to free private_data of 211 * 212 * This shall be used only for fail path handling when tty_add_file was not 213 * called yet. 214 */ 215 void tty_free_file(struct file *file) 216 { 217 struct tty_file_private *priv = file->private_data; 218 219 file->private_data = NULL; 220 kfree(priv); 221 } 222 223 /* Delete file from its tty */ 224 static void tty_del_file(struct file *file) 225 { 226 struct tty_file_private *priv = file->private_data; 227 struct tty_struct *tty = priv->tty; 228 229 spin_lock(&tty->files_lock); 230 list_del(&priv->list); 231 spin_unlock(&tty->files_lock); 232 tty_free_file(file); 233 } 234 235 /** 236 * tty_name - return tty naming 237 * @tty: tty structure 238 * 239 * Convert a tty structure into a name. The name reflects the kernel naming 240 * policy and if udev is in use may not reflect user space 241 * 242 * Locking: none 243 */ 244 const char *tty_name(const struct tty_struct *tty) 245 { 246 if (!tty) /* Hmm. NULL pointer. That's fun. */ 247 return "NULL tty"; 248 return tty->name; 249 } 250 EXPORT_SYMBOL(tty_name); 251 252 const char *tty_driver_name(const struct tty_struct *tty) 253 { 254 if (!tty || !tty->driver) 255 return ""; 256 return tty->driver->name; 257 } 258 259 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, 260 const char *routine) 261 { 262 #ifdef TTY_PARANOIA_CHECK 263 if (!tty) { 264 pr_warn("(%d:%d): %s: NULL tty\n", 265 imajor(inode), iminor(inode), routine); 266 return 1; 267 } 268 #endif 269 return 0; 270 } 271 272 /* Caller must hold tty_lock */ 273 static void check_tty_count(struct tty_struct *tty, const char *routine) 274 { 275 #ifdef CHECK_TTY_COUNT 276 struct list_head *p; 277 int count = 0, kopen_count = 0; 278 279 spin_lock(&tty->files_lock); 280 list_for_each(p, &tty->tty_files) { 281 count++; 282 } 283 spin_unlock(&tty->files_lock); 284 if (tty->driver->type == TTY_DRIVER_TYPE_PTY && 285 tty->driver->subtype == PTY_TYPE_SLAVE && 286 tty->link && tty->link->count) 287 count++; 288 if (tty_port_kopened(tty->port)) 289 kopen_count++; 290 if (tty->count != (count + kopen_count)) { 291 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n", 292 routine, tty->count, count, kopen_count); 293 } 294 #endif 295 } 296 297 /** 298 * get_tty_driver - find device of a tty 299 * @device: device identifier 300 * @index: returns the index of the tty 301 * 302 * This routine returns a tty driver structure, given a device number and also 303 * passes back the index number. 304 * 305 * Locking: caller must hold tty_mutex 306 */ 307 static struct tty_driver *get_tty_driver(dev_t device, int *index) 308 { 309 struct tty_driver *p; 310 311 list_for_each_entry(p, &tty_drivers, tty_drivers) { 312 dev_t base = MKDEV(p->major, p->minor_start); 313 314 if (device < base || device >= base + p->num) 315 continue; 316 *index = device - base; 317 return tty_driver_kref_get(p); 318 } 319 return NULL; 320 } 321 322 /** 323 * tty_dev_name_to_number - return dev_t for device name 324 * @name: user space name of device under /dev 325 * @number: pointer to dev_t that this function will populate 326 * 327 * This function converts device names like ttyS0 or ttyUSB1 into dev_t like 328 * (4, 64) or (188, 1). If no corresponding driver is registered then the 329 * function returns -%ENODEV. 330 * 331 * Locking: this acquires tty_mutex to protect the tty_drivers list from 332 * being modified while we are traversing it, and makes sure to 333 * release it before exiting. 334 */ 335 int tty_dev_name_to_number(const char *name, dev_t *number) 336 { 337 struct tty_driver *p; 338 int ret; 339 int index, prefix_length = 0; 340 const char *str; 341 342 for (str = name; *str && !isdigit(*str); str++) 343 ; 344 345 if (!*str) 346 return -EINVAL; 347 348 ret = kstrtoint(str, 10, &index); 349 if (ret) 350 return ret; 351 352 prefix_length = str - name; 353 mutex_lock(&tty_mutex); 354 355 list_for_each_entry(p, &tty_drivers, tty_drivers) 356 if (prefix_length == strlen(p->name) && strncmp(name, 357 p->name, prefix_length) == 0) { 358 if (index < p->num) { 359 *number = MKDEV(p->major, p->minor_start + index); 360 goto out; 361 } 362 } 363 364 /* if here then driver wasn't found */ 365 ret = -ENODEV; 366 out: 367 mutex_unlock(&tty_mutex); 368 return ret; 369 } 370 EXPORT_SYMBOL_GPL(tty_dev_name_to_number); 371 372 #ifdef CONFIG_CONSOLE_POLL 373 374 /** 375 * tty_find_polling_driver - find device of a polled tty 376 * @name: name string to match 377 * @line: pointer to resulting tty line nr 378 * 379 * This routine returns a tty driver structure, given a name and the condition 380 * that the tty driver is capable of polled operation. 381 */ 382 struct tty_driver *tty_find_polling_driver(char *name, int *line) 383 { 384 struct tty_driver *p, *res = NULL; 385 int tty_line = 0; 386 int len; 387 char *str, *stp; 388 389 for (str = name; *str; str++) 390 if ((*str >= '0' && *str <= '9') || *str == ',') 391 break; 392 if (!*str) 393 return NULL; 394 395 len = str - name; 396 tty_line = simple_strtoul(str, &str, 10); 397 398 mutex_lock(&tty_mutex); 399 /* Search through the tty devices to look for a match */ 400 list_for_each_entry(p, &tty_drivers, tty_drivers) { 401 if (!len || strncmp(name, p->name, len) != 0) 402 continue; 403 stp = str; 404 if (*stp == ',') 405 stp++; 406 if (*stp == '\0') 407 stp = NULL; 408 409 if (tty_line >= 0 && tty_line < p->num && p->ops && 410 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) { 411 res = tty_driver_kref_get(p); 412 *line = tty_line; 413 break; 414 } 415 } 416 mutex_unlock(&tty_mutex); 417 418 return res; 419 } 420 EXPORT_SYMBOL_GPL(tty_find_polling_driver); 421 #endif 422 423 static ssize_t hung_up_tty_read(struct kiocb *iocb, struct iov_iter *to) 424 { 425 return 0; 426 } 427 428 static ssize_t hung_up_tty_write(struct kiocb *iocb, struct iov_iter *from) 429 { 430 return -EIO; 431 } 432 433 /* No kernel lock held - none needed ;) */ 434 static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait) 435 { 436 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM; 437 } 438 439 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd, 440 unsigned long arg) 441 { 442 return cmd == TIOCSPGRP ? -ENOTTY : -EIO; 443 } 444 445 static long hung_up_tty_compat_ioctl(struct file *file, 446 unsigned int cmd, unsigned long arg) 447 { 448 return cmd == TIOCSPGRP ? -ENOTTY : -EIO; 449 } 450 451 static int hung_up_tty_fasync(int fd, struct file *file, int on) 452 { 453 return -ENOTTY; 454 } 455 456 static void tty_show_fdinfo(struct seq_file *m, struct file *file) 457 { 458 struct tty_struct *tty = file_tty(file); 459 460 if (tty && tty->ops && tty->ops->show_fdinfo) 461 tty->ops->show_fdinfo(tty, m); 462 } 463 464 static const struct file_operations tty_fops = { 465 .llseek = no_llseek, 466 .read_iter = tty_read, 467 .write_iter = tty_write, 468 .splice_read = copy_splice_read, 469 .splice_write = iter_file_splice_write, 470 .poll = tty_poll, 471 .unlocked_ioctl = tty_ioctl, 472 .compat_ioctl = tty_compat_ioctl, 473 .open = tty_open, 474 .release = tty_release, 475 .fasync = tty_fasync, 476 .show_fdinfo = tty_show_fdinfo, 477 }; 478 479 static const struct file_operations console_fops = { 480 .llseek = no_llseek, 481 .read_iter = tty_read, 482 .write_iter = redirected_tty_write, 483 .splice_read = copy_splice_read, 484 .splice_write = iter_file_splice_write, 485 .poll = tty_poll, 486 .unlocked_ioctl = tty_ioctl, 487 .compat_ioctl = tty_compat_ioctl, 488 .open = tty_open, 489 .release = tty_release, 490 .fasync = tty_fasync, 491 }; 492 493 static const struct file_operations hung_up_tty_fops = { 494 .llseek = no_llseek, 495 .read_iter = hung_up_tty_read, 496 .write_iter = hung_up_tty_write, 497 .poll = hung_up_tty_poll, 498 .unlocked_ioctl = hung_up_tty_ioctl, 499 .compat_ioctl = hung_up_tty_compat_ioctl, 500 .release = tty_release, 501 .fasync = hung_up_tty_fasync, 502 }; 503 504 static DEFINE_SPINLOCK(redirect_lock); 505 static struct file *redirect; 506 507 /** 508 * tty_wakeup - request more data 509 * @tty: terminal 510 * 511 * Internal and external helper for wakeups of tty. This function informs the 512 * line discipline if present that the driver is ready to receive more output 513 * data. 514 */ 515 void tty_wakeup(struct tty_struct *tty) 516 { 517 struct tty_ldisc *ld; 518 519 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { 520 ld = tty_ldisc_ref(tty); 521 if (ld) { 522 if (ld->ops->write_wakeup) 523 ld->ops->write_wakeup(tty); 524 tty_ldisc_deref(ld); 525 } 526 } 527 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT); 528 } 529 EXPORT_SYMBOL_GPL(tty_wakeup); 530 531 /** 532 * tty_release_redirect - Release a redirect on a pty if present 533 * @tty: tty device 534 * 535 * This is available to the pty code so if the master closes, if the slave is a 536 * redirect it can release the redirect. 537 */ 538 static struct file *tty_release_redirect(struct tty_struct *tty) 539 { 540 struct file *f = NULL; 541 542 spin_lock(&redirect_lock); 543 if (redirect && file_tty(redirect) == tty) { 544 f = redirect; 545 redirect = NULL; 546 } 547 spin_unlock(&redirect_lock); 548 549 return f; 550 } 551 552 /** 553 * __tty_hangup - actual handler for hangup events 554 * @tty: tty device 555 * @exit_session: if non-zero, signal all foreground group processes 556 * 557 * This can be called by a "kworker" kernel thread. That is process synchronous 558 * but doesn't hold any locks, so we need to make sure we have the appropriate 559 * locks for what we're doing. 560 * 561 * The hangup event clears any pending redirections onto the hung up device. It 562 * ensures future writes will error and it does the needed line discipline 563 * hangup and signal delivery. The tty object itself remains intact. 564 * 565 * Locking: 566 * * BTM 567 * 568 * * redirect lock for undoing redirection 569 * * file list lock for manipulating list of ttys 570 * * tty_ldiscs_lock from called functions 571 * * termios_rwsem resetting termios data 572 * * tasklist_lock to walk task list for hangup event 573 * 574 * * ->siglock to protect ->signal/->sighand 575 * 576 */ 577 static void __tty_hangup(struct tty_struct *tty, int exit_session) 578 { 579 struct file *cons_filp = NULL; 580 struct file *filp, *f; 581 struct tty_file_private *priv; 582 int closecount = 0, n; 583 int refs; 584 585 if (!tty) 586 return; 587 588 f = tty_release_redirect(tty); 589 590 tty_lock(tty); 591 592 if (test_bit(TTY_HUPPED, &tty->flags)) { 593 tty_unlock(tty); 594 return; 595 } 596 597 /* 598 * Some console devices aren't actually hung up for technical and 599 * historical reasons, which can lead to indefinite interruptible 600 * sleep in n_tty_read(). The following explicitly tells 601 * n_tty_read() to abort readers. 602 */ 603 set_bit(TTY_HUPPING, &tty->flags); 604 605 /* inuse_filps is protected by the single tty lock, 606 * this really needs to change if we want to flush the 607 * workqueue with the lock held. 608 */ 609 check_tty_count(tty, "tty_hangup"); 610 611 spin_lock(&tty->files_lock); 612 /* This breaks for file handles being sent over AF_UNIX sockets ? */ 613 list_for_each_entry(priv, &tty->tty_files, list) { 614 filp = priv->file; 615 if (filp->f_op->write_iter == redirected_tty_write) 616 cons_filp = filp; 617 if (filp->f_op->write_iter != tty_write) 618 continue; 619 closecount++; 620 __tty_fasync(-1, filp, 0); /* can't block */ 621 filp->f_op = &hung_up_tty_fops; 622 } 623 spin_unlock(&tty->files_lock); 624 625 refs = tty_signal_session_leader(tty, exit_session); 626 /* Account for the p->signal references we killed */ 627 while (refs--) 628 tty_kref_put(tty); 629 630 tty_ldisc_hangup(tty, cons_filp != NULL); 631 632 spin_lock_irq(&tty->ctrl.lock); 633 clear_bit(TTY_THROTTLED, &tty->flags); 634 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 635 put_pid(tty->ctrl.session); 636 put_pid(tty->ctrl.pgrp); 637 tty->ctrl.session = NULL; 638 tty->ctrl.pgrp = NULL; 639 tty->ctrl.pktstatus = 0; 640 spin_unlock_irq(&tty->ctrl.lock); 641 642 /* 643 * If one of the devices matches a console pointer, we 644 * cannot just call hangup() because that will cause 645 * tty->count and state->count to go out of sync. 646 * So we just call close() the right number of times. 647 */ 648 if (cons_filp) { 649 if (tty->ops->close) 650 for (n = 0; n < closecount; n++) 651 tty->ops->close(tty, cons_filp); 652 } else if (tty->ops->hangup) 653 tty->ops->hangup(tty); 654 /* 655 * We don't want to have driver/ldisc interactions beyond the ones 656 * we did here. The driver layer expects no calls after ->hangup() 657 * from the ldisc side, which is now guaranteed. 658 */ 659 set_bit(TTY_HUPPED, &tty->flags); 660 clear_bit(TTY_HUPPING, &tty->flags); 661 tty_unlock(tty); 662 663 if (f) 664 fput(f); 665 } 666 667 static void do_tty_hangup(struct work_struct *work) 668 { 669 struct tty_struct *tty = 670 container_of(work, struct tty_struct, hangup_work); 671 672 __tty_hangup(tty, 0); 673 } 674 675 /** 676 * tty_hangup - trigger a hangup event 677 * @tty: tty to hangup 678 * 679 * A carrier loss (virtual or otherwise) has occurred on @tty. Schedule a 680 * hangup sequence to run after this event. 681 */ 682 void tty_hangup(struct tty_struct *tty) 683 { 684 tty_debug_hangup(tty, "hangup\n"); 685 schedule_work(&tty->hangup_work); 686 } 687 EXPORT_SYMBOL(tty_hangup); 688 689 /** 690 * tty_vhangup - process vhangup 691 * @tty: tty to hangup 692 * 693 * The user has asked via system call for the terminal to be hung up. We do 694 * this synchronously so that when the syscall returns the process is complete. 695 * That guarantee is necessary for security reasons. 696 */ 697 void tty_vhangup(struct tty_struct *tty) 698 { 699 tty_debug_hangup(tty, "vhangup\n"); 700 __tty_hangup(tty, 0); 701 } 702 EXPORT_SYMBOL(tty_vhangup); 703 704 705 /** 706 * tty_vhangup_self - process vhangup for own ctty 707 * 708 * Perform a vhangup on the current controlling tty 709 */ 710 void tty_vhangup_self(void) 711 { 712 struct tty_struct *tty; 713 714 tty = get_current_tty(); 715 if (tty) { 716 tty_vhangup(tty); 717 tty_kref_put(tty); 718 } 719 } 720 721 /** 722 * tty_vhangup_session - hangup session leader exit 723 * @tty: tty to hangup 724 * 725 * The session leader is exiting and hanging up its controlling terminal. 726 * Every process in the foreground process group is signalled %SIGHUP. 727 * 728 * We do this synchronously so that when the syscall returns the process is 729 * complete. That guarantee is necessary for security reasons. 730 */ 731 void tty_vhangup_session(struct tty_struct *tty) 732 { 733 tty_debug_hangup(tty, "session hangup\n"); 734 __tty_hangup(tty, 1); 735 } 736 737 /** 738 * tty_hung_up_p - was tty hung up 739 * @filp: file pointer of tty 740 * 741 * Return: true if the tty has been subject to a vhangup or a carrier loss 742 */ 743 int tty_hung_up_p(struct file *filp) 744 { 745 return (filp && filp->f_op == &hung_up_tty_fops); 746 } 747 EXPORT_SYMBOL(tty_hung_up_p); 748 749 void __stop_tty(struct tty_struct *tty) 750 { 751 if (tty->flow.stopped) 752 return; 753 tty->flow.stopped = true; 754 if (tty->ops->stop) 755 tty->ops->stop(tty); 756 } 757 758 /** 759 * stop_tty - propagate flow control 760 * @tty: tty to stop 761 * 762 * Perform flow control to the driver. May be called on an already stopped 763 * device and will not re-call the &tty_driver->stop() method. 764 * 765 * This functionality is used by both the line disciplines for halting incoming 766 * flow and by the driver. It may therefore be called from any context, may be 767 * under the tty %atomic_write_lock but not always. 768 * 769 * Locking: 770 * flow.lock 771 */ 772 void stop_tty(struct tty_struct *tty) 773 { 774 unsigned long flags; 775 776 spin_lock_irqsave(&tty->flow.lock, flags); 777 __stop_tty(tty); 778 spin_unlock_irqrestore(&tty->flow.lock, flags); 779 } 780 EXPORT_SYMBOL(stop_tty); 781 782 void __start_tty(struct tty_struct *tty) 783 { 784 if (!tty->flow.stopped || tty->flow.tco_stopped) 785 return; 786 tty->flow.stopped = false; 787 if (tty->ops->start) 788 tty->ops->start(tty); 789 tty_wakeup(tty); 790 } 791 792 /** 793 * start_tty - propagate flow control 794 * @tty: tty to start 795 * 796 * Start a tty that has been stopped if at all possible. If @tty was previously 797 * stopped and is now being started, the &tty_driver->start() method is invoked 798 * and the line discipline woken. 799 * 800 * Locking: 801 * flow.lock 802 */ 803 void start_tty(struct tty_struct *tty) 804 { 805 unsigned long flags; 806 807 spin_lock_irqsave(&tty->flow.lock, flags); 808 __start_tty(tty); 809 spin_unlock_irqrestore(&tty->flow.lock, flags); 810 } 811 EXPORT_SYMBOL(start_tty); 812 813 static void tty_update_time(struct tty_struct *tty, bool mtime) 814 { 815 time64_t sec = ktime_get_real_seconds(); 816 struct tty_file_private *priv; 817 818 spin_lock(&tty->files_lock); 819 list_for_each_entry(priv, &tty->tty_files, list) { 820 struct inode *inode = file_inode(priv->file); 821 struct timespec64 *time = mtime ? &inode->i_mtime : &inode->i_atime; 822 823 /* 824 * We only care if the two values differ in anything other than the 825 * lower three bits (i.e every 8 seconds). If so, then we can update 826 * the time of the tty device, otherwise it could be construded as a 827 * security leak to let userspace know the exact timing of the tty. 828 */ 829 if ((sec ^ time->tv_sec) & ~7) 830 time->tv_sec = sec; 831 } 832 spin_unlock(&tty->files_lock); 833 } 834 835 /* 836 * Iterate on the ldisc ->read() function until we've gotten all 837 * the data the ldisc has for us. 838 * 839 * The "cookie" is something that the ldisc read function can fill 840 * in to let us know that there is more data to be had. 841 * 842 * We promise to continue to call the ldisc until it stops returning 843 * data or clears the cookie. The cookie may be something that the 844 * ldisc maintains state for and needs to free. 845 */ 846 static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, 847 struct file *file, struct iov_iter *to) 848 { 849 int retval = 0; 850 void *cookie = NULL; 851 unsigned long offset = 0; 852 char kernel_buf[64]; 853 size_t count = iov_iter_count(to); 854 855 do { 856 int size, copied; 857 858 size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count; 859 size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset); 860 if (!size) 861 break; 862 863 if (size < 0) { 864 /* Did we have an earlier error (ie -EFAULT)? */ 865 if (retval) 866 break; 867 retval = size; 868 869 /* 870 * -EOVERFLOW means we didn't have enough space 871 * for a whole packet, and we shouldn't return 872 * a partial result. 873 */ 874 if (retval == -EOVERFLOW) 875 offset = 0; 876 break; 877 } 878 879 copied = copy_to_iter(kernel_buf, size, to); 880 offset += copied; 881 count -= copied; 882 883 /* 884 * If the user copy failed, we still need to do another ->read() 885 * call if we had a cookie to let the ldisc clear up. 886 * 887 * But make sure size is zeroed. 888 */ 889 if (unlikely(copied != size)) { 890 count = 0; 891 retval = -EFAULT; 892 } 893 } while (cookie); 894 895 /* We always clear tty buffer in case they contained passwords */ 896 memzero_explicit(kernel_buf, sizeof(kernel_buf)); 897 return offset ? offset : retval; 898 } 899 900 901 /** 902 * tty_read - read method for tty device files 903 * @iocb: kernel I/O control block 904 * @to: destination for the data read 905 * 906 * Perform the read system call function on this terminal device. Checks 907 * for hung up devices before calling the line discipline method. 908 * 909 * Locking: 910 * Locks the line discipline internally while needed. Multiple read calls 911 * may be outstanding in parallel. 912 */ 913 static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to) 914 { 915 int i; 916 struct file *file = iocb->ki_filp; 917 struct inode *inode = file_inode(file); 918 struct tty_struct *tty = file_tty(file); 919 struct tty_ldisc *ld; 920 921 if (tty_paranoia_check(tty, inode, "tty_read")) 922 return -EIO; 923 if (!tty || tty_io_error(tty)) 924 return -EIO; 925 926 /* We want to wait for the line discipline to sort out in this 927 * situation. 928 */ 929 ld = tty_ldisc_ref_wait(tty); 930 if (!ld) 931 return hung_up_tty_read(iocb, to); 932 i = -EIO; 933 if (ld->ops->read) 934 i = iterate_tty_read(ld, tty, file, to); 935 tty_ldisc_deref(ld); 936 937 if (i > 0) 938 tty_update_time(tty, false); 939 940 return i; 941 } 942 943 void tty_write_unlock(struct tty_struct *tty) 944 { 945 mutex_unlock(&tty->atomic_write_lock); 946 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT); 947 } 948 949 int tty_write_lock(struct tty_struct *tty, bool ndelay) 950 { 951 if (!mutex_trylock(&tty->atomic_write_lock)) { 952 if (ndelay) 953 return -EAGAIN; 954 if (mutex_lock_interruptible(&tty->atomic_write_lock)) 955 return -ERESTARTSYS; 956 } 957 return 0; 958 } 959 960 /* 961 * Split writes up in sane blocksizes to avoid 962 * denial-of-service type attacks 963 */ 964 static ssize_t iterate_tty_write(struct tty_ldisc *ld, struct tty_struct *tty, 965 struct file *file, struct iov_iter *from) 966 { 967 size_t count = iov_iter_count(from); 968 ssize_t ret, written = 0; 969 unsigned int chunk; 970 971 ret = tty_write_lock(tty, file->f_flags & O_NDELAY); 972 if (ret < 0) 973 return ret; 974 975 /* 976 * We chunk up writes into a temporary buffer. This 977 * simplifies low-level drivers immensely, since they 978 * don't have locking issues and user mode accesses. 979 * 980 * But if TTY_NO_WRITE_SPLIT is set, we should use a 981 * big chunk-size.. 982 * 983 * The default chunk-size is 2kB, because the NTTY 984 * layer has problems with bigger chunks. It will 985 * claim to be able to handle more characters than 986 * it actually does. 987 */ 988 chunk = 2048; 989 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) 990 chunk = 65536; 991 if (count < chunk) 992 chunk = count; 993 994 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ 995 if (tty->write_cnt < chunk) { 996 unsigned char *buf_chunk; 997 998 if (chunk < 1024) 999 chunk = 1024; 1000 1001 buf_chunk = kvmalloc(chunk, GFP_KERNEL | __GFP_RETRY_MAYFAIL); 1002 if (!buf_chunk) { 1003 ret = -ENOMEM; 1004 goto out; 1005 } 1006 kvfree(tty->write_buf); 1007 tty->write_cnt = chunk; 1008 tty->write_buf = buf_chunk; 1009 } 1010 1011 /* Do the write .. */ 1012 for (;;) { 1013 size_t size = count; 1014 1015 if (size > chunk) 1016 size = chunk; 1017 1018 ret = -EFAULT; 1019 if (copy_from_iter(tty->write_buf, size, from) != size) 1020 break; 1021 1022 ret = ld->ops->write(tty, file, tty->write_buf, size); 1023 if (ret <= 0) 1024 break; 1025 1026 written += ret; 1027 if (ret > size) 1028 break; 1029 1030 /* FIXME! Have Al check this! */ 1031 if (ret != size) 1032 iov_iter_revert(from, size-ret); 1033 1034 count -= ret; 1035 if (!count) 1036 break; 1037 ret = -ERESTARTSYS; 1038 if (signal_pending(current)) 1039 break; 1040 cond_resched(); 1041 } 1042 if (written) { 1043 tty_update_time(tty, true); 1044 ret = written; 1045 } 1046 out: 1047 tty_write_unlock(tty); 1048 return ret; 1049 } 1050 1051 /** 1052 * tty_write_message - write a message to a certain tty, not just the console. 1053 * @tty: the destination tty_struct 1054 * @msg: the message to write 1055 * 1056 * This is used for messages that need to be redirected to a specific tty. We 1057 * don't put it into the syslog queue right now maybe in the future if really 1058 * needed. 1059 * 1060 * We must still hold the BTM and test the CLOSING flag for the moment. 1061 */ 1062 void tty_write_message(struct tty_struct *tty, char *msg) 1063 { 1064 if (tty) { 1065 mutex_lock(&tty->atomic_write_lock); 1066 tty_lock(tty); 1067 if (tty->ops->write && tty->count > 0) 1068 tty->ops->write(tty, msg, strlen(msg)); 1069 tty_unlock(tty); 1070 tty_write_unlock(tty); 1071 } 1072 } 1073 1074 static ssize_t file_tty_write(struct file *file, struct kiocb *iocb, struct iov_iter *from) 1075 { 1076 struct tty_struct *tty = file_tty(file); 1077 struct tty_ldisc *ld; 1078 ssize_t ret; 1079 1080 if (tty_paranoia_check(tty, file_inode(file), "tty_write")) 1081 return -EIO; 1082 if (!tty || !tty->ops->write || tty_io_error(tty)) 1083 return -EIO; 1084 /* Short term debug to catch buggy drivers */ 1085 if (tty->ops->write_room == NULL) 1086 tty_err(tty, "missing write_room method\n"); 1087 ld = tty_ldisc_ref_wait(tty); 1088 if (!ld) 1089 return hung_up_tty_write(iocb, from); 1090 if (!ld->ops->write) 1091 ret = -EIO; 1092 else 1093 ret = iterate_tty_write(ld, tty, file, from); 1094 tty_ldisc_deref(ld); 1095 return ret; 1096 } 1097 1098 /** 1099 * tty_write - write method for tty device file 1100 * @iocb: kernel I/O control block 1101 * @from: iov_iter with data to write 1102 * 1103 * Write data to a tty device via the line discipline. 1104 * 1105 * Locking: 1106 * Locks the line discipline as required 1107 * Writes to the tty driver are serialized by the atomic_write_lock 1108 * and are then processed in chunks to the device. The line 1109 * discipline write method will not be invoked in parallel for 1110 * each device. 1111 */ 1112 static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from) 1113 { 1114 return file_tty_write(iocb->ki_filp, iocb, from); 1115 } 1116 1117 ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter) 1118 { 1119 struct file *p = NULL; 1120 1121 spin_lock(&redirect_lock); 1122 if (redirect) 1123 p = get_file(redirect); 1124 spin_unlock(&redirect_lock); 1125 1126 /* 1127 * We know the redirected tty is just another tty, we can 1128 * call file_tty_write() directly with that file pointer. 1129 */ 1130 if (p) { 1131 ssize_t res; 1132 1133 res = file_tty_write(p, iocb, iter); 1134 fput(p); 1135 return res; 1136 } 1137 return tty_write(iocb, iter); 1138 } 1139 1140 /** 1141 * tty_send_xchar - send priority character 1142 * @tty: the tty to send to 1143 * @ch: xchar to send 1144 * 1145 * Send a high priority character to the tty even if stopped. 1146 * 1147 * Locking: none for xchar method, write ordering for write method. 1148 */ 1149 int tty_send_xchar(struct tty_struct *tty, char ch) 1150 { 1151 bool was_stopped = tty->flow.stopped; 1152 1153 if (tty->ops->send_xchar) { 1154 down_read(&tty->termios_rwsem); 1155 tty->ops->send_xchar(tty, ch); 1156 up_read(&tty->termios_rwsem); 1157 return 0; 1158 } 1159 1160 if (tty_write_lock(tty, false) < 0) 1161 return -ERESTARTSYS; 1162 1163 down_read(&tty->termios_rwsem); 1164 if (was_stopped) 1165 start_tty(tty); 1166 tty->ops->write(tty, &ch, 1); 1167 if (was_stopped) 1168 stop_tty(tty); 1169 up_read(&tty->termios_rwsem); 1170 tty_write_unlock(tty); 1171 return 0; 1172 } 1173 1174 /** 1175 * pty_line_name - generate name for a pty 1176 * @driver: the tty driver in use 1177 * @index: the minor number 1178 * @p: output buffer of at least 6 bytes 1179 * 1180 * Generate a name from a @driver reference and write it to the output buffer 1181 * @p. 1182 * 1183 * Locking: None 1184 */ 1185 static void pty_line_name(struct tty_driver *driver, int index, char *p) 1186 { 1187 static const char ptychar[] = "pqrstuvwxyzabcde"; 1188 int i = index + driver->name_base; 1189 /* ->name is initialized to "ttyp", but "tty" is expected */ 1190 sprintf(p, "%s%c%x", 1191 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, 1192 ptychar[i >> 4 & 0xf], i & 0xf); 1193 } 1194 1195 /** 1196 * tty_line_name - generate name for a tty 1197 * @driver: the tty driver in use 1198 * @index: the minor number 1199 * @p: output buffer of at least 7 bytes 1200 * 1201 * Generate a name from a @driver reference and write it to the output buffer 1202 * @p. 1203 * 1204 * Locking: None 1205 */ 1206 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p) 1207 { 1208 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE) 1209 return sprintf(p, "%s", driver->name); 1210 else 1211 return sprintf(p, "%s%d", driver->name, 1212 index + driver->name_base); 1213 } 1214 1215 /** 1216 * tty_driver_lookup_tty() - find an existing tty, if any 1217 * @driver: the driver for the tty 1218 * @file: file object 1219 * @idx: the minor number 1220 * 1221 * Return: the tty, if found. If not found, return %NULL or ERR_PTR() if the 1222 * driver lookup() method returns an error. 1223 * 1224 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref. 1225 */ 1226 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, 1227 struct file *file, int idx) 1228 { 1229 struct tty_struct *tty; 1230 1231 if (driver->ops->lookup) { 1232 if (!file) 1233 tty = ERR_PTR(-EIO); 1234 else 1235 tty = driver->ops->lookup(driver, file, idx); 1236 } else { 1237 if (idx >= driver->num) 1238 return ERR_PTR(-EINVAL); 1239 tty = driver->ttys[idx]; 1240 } 1241 if (!IS_ERR(tty)) 1242 tty_kref_get(tty); 1243 return tty; 1244 } 1245 1246 /** 1247 * tty_init_termios - helper for termios setup 1248 * @tty: the tty to set up 1249 * 1250 * Initialise the termios structure for this tty. This runs under the 1251 * %tty_mutex currently so we can be relaxed about ordering. 1252 */ 1253 void tty_init_termios(struct tty_struct *tty) 1254 { 1255 struct ktermios *tp; 1256 int idx = tty->index; 1257 1258 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) 1259 tty->termios = tty->driver->init_termios; 1260 else { 1261 /* Check for lazy saved data */ 1262 tp = tty->driver->termios[idx]; 1263 if (tp != NULL) { 1264 tty->termios = *tp; 1265 tty->termios.c_line = tty->driver->init_termios.c_line; 1266 } else 1267 tty->termios = tty->driver->init_termios; 1268 } 1269 /* Compatibility until drivers always set this */ 1270 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios); 1271 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios); 1272 } 1273 EXPORT_SYMBOL_GPL(tty_init_termios); 1274 1275 /** 1276 * tty_standard_install - usual tty->ops->install 1277 * @driver: the driver for the tty 1278 * @tty: the tty 1279 * 1280 * If the @driver overrides @tty->ops->install, it still can call this function 1281 * to perform the standard install operations. 1282 */ 1283 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty) 1284 { 1285 tty_init_termios(tty); 1286 tty_driver_kref_get(driver); 1287 tty->count++; 1288 driver->ttys[tty->index] = tty; 1289 return 0; 1290 } 1291 EXPORT_SYMBOL_GPL(tty_standard_install); 1292 1293 /** 1294 * tty_driver_install_tty() - install a tty entry in the driver 1295 * @driver: the driver for the tty 1296 * @tty: the tty 1297 * 1298 * Install a tty object into the driver tables. The @tty->index field will be 1299 * set by the time this is called. This method is responsible for ensuring any 1300 * need additional structures are allocated and configured. 1301 * 1302 * Locking: tty_mutex for now 1303 */ 1304 static int tty_driver_install_tty(struct tty_driver *driver, 1305 struct tty_struct *tty) 1306 { 1307 return driver->ops->install ? driver->ops->install(driver, tty) : 1308 tty_standard_install(driver, tty); 1309 } 1310 1311 /** 1312 * tty_driver_remove_tty() - remove a tty from the driver tables 1313 * @driver: the driver for the tty 1314 * @tty: tty to remove 1315 * 1316 * Remove a tty object from the driver tables. The tty->index field will be set 1317 * by the time this is called. 1318 * 1319 * Locking: tty_mutex for now 1320 */ 1321 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty) 1322 { 1323 if (driver->ops->remove) 1324 driver->ops->remove(driver, tty); 1325 else 1326 driver->ttys[tty->index] = NULL; 1327 } 1328 1329 /** 1330 * tty_reopen() - fast re-open of an open tty 1331 * @tty: the tty to open 1332 * 1333 * Re-opens on master ptys are not allowed and return -%EIO. 1334 * 1335 * Locking: Caller must hold tty_lock 1336 * Return: 0 on success, -errno on error. 1337 */ 1338 static int tty_reopen(struct tty_struct *tty) 1339 { 1340 struct tty_driver *driver = tty->driver; 1341 struct tty_ldisc *ld; 1342 int retval = 0; 1343 1344 if (driver->type == TTY_DRIVER_TYPE_PTY && 1345 driver->subtype == PTY_TYPE_MASTER) 1346 return -EIO; 1347 1348 if (!tty->count) 1349 return -EAGAIN; 1350 1351 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) 1352 return -EBUSY; 1353 1354 ld = tty_ldisc_ref_wait(tty); 1355 if (ld) { 1356 tty_ldisc_deref(ld); 1357 } else { 1358 retval = tty_ldisc_lock(tty, 5 * HZ); 1359 if (retval) 1360 return retval; 1361 1362 if (!tty->ldisc) 1363 retval = tty_ldisc_reinit(tty, tty->termios.c_line); 1364 tty_ldisc_unlock(tty); 1365 } 1366 1367 if (retval == 0) 1368 tty->count++; 1369 1370 return retval; 1371 } 1372 1373 /** 1374 * tty_init_dev - initialise a tty device 1375 * @driver: tty driver we are opening a device on 1376 * @idx: device index 1377 * 1378 * Prepare a tty device. This may not be a "new" clean device but could also be 1379 * an active device. The pty drivers require special handling because of this. 1380 * 1381 * Locking: 1382 * The function is called under the tty_mutex, which protects us from the 1383 * tty struct or driver itself going away. 1384 * 1385 * On exit the tty device has the line discipline attached and a reference 1386 * count of 1. If a pair was created for pty/tty use and the other was a pty 1387 * master then it too has a reference count of 1. 1388 * 1389 * WSH 06/09/97: Rewritten to remove races and properly clean up after a failed 1390 * open. The new code protects the open with a mutex, so it's really quite 1391 * straightforward. The mutex locking can probably be relaxed for the (most 1392 * common) case of reopening a tty. 1393 * 1394 * Return: new tty structure 1395 */ 1396 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx) 1397 { 1398 struct tty_struct *tty; 1399 int retval; 1400 1401 /* 1402 * First time open is complex, especially for PTY devices. 1403 * This code guarantees that either everything succeeds and the 1404 * TTY is ready for operation, or else the table slots are vacated 1405 * and the allocated memory released. (Except that the termios 1406 * may be retained.) 1407 */ 1408 1409 if (!try_module_get(driver->owner)) 1410 return ERR_PTR(-ENODEV); 1411 1412 tty = alloc_tty_struct(driver, idx); 1413 if (!tty) { 1414 retval = -ENOMEM; 1415 goto err_module_put; 1416 } 1417 1418 tty_lock(tty); 1419 retval = tty_driver_install_tty(driver, tty); 1420 if (retval < 0) 1421 goto err_free_tty; 1422 1423 if (!tty->port) 1424 tty->port = driver->ports[idx]; 1425 1426 if (WARN_RATELIMIT(!tty->port, 1427 "%s: %s driver does not set tty->port. This would crash the kernel. Fix the driver!\n", 1428 __func__, tty->driver->name)) { 1429 retval = -EINVAL; 1430 goto err_release_lock; 1431 } 1432 1433 retval = tty_ldisc_lock(tty, 5 * HZ); 1434 if (retval) 1435 goto err_release_lock; 1436 tty->port->itty = tty; 1437 1438 /* 1439 * Structures all installed ... call the ldisc open routines. 1440 * If we fail here just call release_tty to clean up. No need 1441 * to decrement the use counts, as release_tty doesn't care. 1442 */ 1443 retval = tty_ldisc_setup(tty, tty->link); 1444 if (retval) 1445 goto err_release_tty; 1446 tty_ldisc_unlock(tty); 1447 /* Return the tty locked so that it cannot vanish under the caller */ 1448 return tty; 1449 1450 err_free_tty: 1451 tty_unlock(tty); 1452 free_tty_struct(tty); 1453 err_module_put: 1454 module_put(driver->owner); 1455 return ERR_PTR(retval); 1456 1457 /* call the tty release_tty routine to clean out this slot */ 1458 err_release_tty: 1459 tty_ldisc_unlock(tty); 1460 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n", 1461 retval, idx); 1462 err_release_lock: 1463 tty_unlock(tty); 1464 release_tty(tty, idx); 1465 return ERR_PTR(retval); 1466 } 1467 1468 /** 1469 * tty_save_termios() - save tty termios data in driver table 1470 * @tty: tty whose termios data to save 1471 * 1472 * Locking: Caller guarantees serialisation with tty_init_termios(). 1473 */ 1474 void tty_save_termios(struct tty_struct *tty) 1475 { 1476 struct ktermios *tp; 1477 int idx = tty->index; 1478 1479 /* If the port is going to reset then it has no termios to save */ 1480 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) 1481 return; 1482 1483 /* Stash the termios data */ 1484 tp = tty->driver->termios[idx]; 1485 if (tp == NULL) { 1486 tp = kmalloc(sizeof(*tp), GFP_KERNEL); 1487 if (tp == NULL) 1488 return; 1489 tty->driver->termios[idx] = tp; 1490 } 1491 *tp = tty->termios; 1492 } 1493 EXPORT_SYMBOL_GPL(tty_save_termios); 1494 1495 /** 1496 * tty_flush_works - flush all works of a tty/pty pair 1497 * @tty: tty device to flush works for (or either end of a pty pair) 1498 * 1499 * Sync flush all works belonging to @tty (and the 'other' tty). 1500 */ 1501 static void tty_flush_works(struct tty_struct *tty) 1502 { 1503 flush_work(&tty->SAK_work); 1504 flush_work(&tty->hangup_work); 1505 if (tty->link) { 1506 flush_work(&tty->link->SAK_work); 1507 flush_work(&tty->link->hangup_work); 1508 } 1509 } 1510 1511 /** 1512 * release_one_tty - release tty structure memory 1513 * @work: work of tty we are obliterating 1514 * 1515 * Releases memory associated with a tty structure, and clears out the 1516 * driver table slots. This function is called when a device is no longer 1517 * in use. It also gets called when setup of a device fails. 1518 * 1519 * Locking: 1520 * takes the file list lock internally when working on the list of ttys 1521 * that the driver keeps. 1522 * 1523 * This method gets called from a work queue so that the driver private 1524 * cleanup ops can sleep (needed for USB at least) 1525 */ 1526 static void release_one_tty(struct work_struct *work) 1527 { 1528 struct tty_struct *tty = 1529 container_of(work, struct tty_struct, hangup_work); 1530 struct tty_driver *driver = tty->driver; 1531 struct module *owner = driver->owner; 1532 1533 if (tty->ops->cleanup) 1534 tty->ops->cleanup(tty); 1535 1536 tty_driver_kref_put(driver); 1537 module_put(owner); 1538 1539 spin_lock(&tty->files_lock); 1540 list_del_init(&tty->tty_files); 1541 spin_unlock(&tty->files_lock); 1542 1543 put_pid(tty->ctrl.pgrp); 1544 put_pid(tty->ctrl.session); 1545 free_tty_struct(tty); 1546 } 1547 1548 static void queue_release_one_tty(struct kref *kref) 1549 { 1550 struct tty_struct *tty = container_of(kref, struct tty_struct, kref); 1551 1552 /* The hangup queue is now free so we can reuse it rather than 1553 * waste a chunk of memory for each port. 1554 */ 1555 INIT_WORK(&tty->hangup_work, release_one_tty); 1556 schedule_work(&tty->hangup_work); 1557 } 1558 1559 /** 1560 * tty_kref_put - release a tty kref 1561 * @tty: tty device 1562 * 1563 * Release a reference to the @tty device and if need be let the kref layer 1564 * destruct the object for us. 1565 */ 1566 void tty_kref_put(struct tty_struct *tty) 1567 { 1568 if (tty) 1569 kref_put(&tty->kref, queue_release_one_tty); 1570 } 1571 EXPORT_SYMBOL(tty_kref_put); 1572 1573 /** 1574 * release_tty - release tty structure memory 1575 * @tty: tty device release 1576 * @idx: index of the tty device release 1577 * 1578 * Release both @tty and a possible linked partner (think pty pair), 1579 * and decrement the refcount of the backing module. 1580 * 1581 * Locking: 1582 * tty_mutex 1583 * takes the file list lock internally when working on the list of ttys 1584 * that the driver keeps. 1585 */ 1586 static void release_tty(struct tty_struct *tty, int idx) 1587 { 1588 /* This should always be true but check for the moment */ 1589 WARN_ON(tty->index != idx); 1590 WARN_ON(!mutex_is_locked(&tty_mutex)); 1591 if (tty->ops->shutdown) 1592 tty->ops->shutdown(tty); 1593 tty_save_termios(tty); 1594 tty_driver_remove_tty(tty->driver, tty); 1595 if (tty->port) 1596 tty->port->itty = NULL; 1597 if (tty->link) 1598 tty->link->port->itty = NULL; 1599 if (tty->port) 1600 tty_buffer_cancel_work(tty->port); 1601 if (tty->link) 1602 tty_buffer_cancel_work(tty->link->port); 1603 1604 tty_kref_put(tty->link); 1605 tty_kref_put(tty); 1606 } 1607 1608 /** 1609 * tty_release_checks - check a tty before real release 1610 * @tty: tty to check 1611 * @idx: index of the tty 1612 * 1613 * Performs some paranoid checking before true release of the @tty. This is a 1614 * no-op unless %TTY_PARANOIA_CHECK is defined. 1615 */ 1616 static int tty_release_checks(struct tty_struct *tty, int idx) 1617 { 1618 #ifdef TTY_PARANOIA_CHECK 1619 if (idx < 0 || idx >= tty->driver->num) { 1620 tty_debug(tty, "bad idx %d\n", idx); 1621 return -1; 1622 } 1623 1624 /* not much to check for devpts */ 1625 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) 1626 return 0; 1627 1628 if (tty != tty->driver->ttys[idx]) { 1629 tty_debug(tty, "bad driver table[%d] = %p\n", 1630 idx, tty->driver->ttys[idx]); 1631 return -1; 1632 } 1633 if (tty->driver->other) { 1634 struct tty_struct *o_tty = tty->link; 1635 1636 if (o_tty != tty->driver->other->ttys[idx]) { 1637 tty_debug(tty, "bad other table[%d] = %p\n", 1638 idx, tty->driver->other->ttys[idx]); 1639 return -1; 1640 } 1641 if (o_tty->link != tty) { 1642 tty_debug(tty, "bad link = %p\n", o_tty->link); 1643 return -1; 1644 } 1645 } 1646 #endif 1647 return 0; 1648 } 1649 1650 /** 1651 * tty_kclose - closes tty opened by tty_kopen 1652 * @tty: tty device 1653 * 1654 * Performs the final steps to release and free a tty device. It is the same as 1655 * tty_release_struct() except that it also resets %TTY_PORT_KOPENED flag on 1656 * @tty->port. 1657 */ 1658 void tty_kclose(struct tty_struct *tty) 1659 { 1660 /* 1661 * Ask the line discipline code to release its structures 1662 */ 1663 tty_ldisc_release(tty); 1664 1665 /* Wait for pending work before tty destruction commences */ 1666 tty_flush_works(tty); 1667 1668 tty_debug_hangup(tty, "freeing structure\n"); 1669 /* 1670 * The release_tty function takes care of the details of clearing 1671 * the slots and preserving the termios structure. 1672 */ 1673 mutex_lock(&tty_mutex); 1674 tty_port_set_kopened(tty->port, 0); 1675 release_tty(tty, tty->index); 1676 mutex_unlock(&tty_mutex); 1677 } 1678 EXPORT_SYMBOL_GPL(tty_kclose); 1679 1680 /** 1681 * tty_release_struct - release a tty struct 1682 * @tty: tty device 1683 * @idx: index of the tty 1684 * 1685 * Performs the final steps to release and free a tty device. It is roughly the 1686 * reverse of tty_init_dev(). 1687 */ 1688 void tty_release_struct(struct tty_struct *tty, int idx) 1689 { 1690 /* 1691 * Ask the line discipline code to release its structures 1692 */ 1693 tty_ldisc_release(tty); 1694 1695 /* Wait for pending work before tty destruction commmences */ 1696 tty_flush_works(tty); 1697 1698 tty_debug_hangup(tty, "freeing structure\n"); 1699 /* 1700 * The release_tty function takes care of the details of clearing 1701 * the slots and preserving the termios structure. 1702 */ 1703 mutex_lock(&tty_mutex); 1704 release_tty(tty, idx); 1705 mutex_unlock(&tty_mutex); 1706 } 1707 EXPORT_SYMBOL_GPL(tty_release_struct); 1708 1709 /** 1710 * tty_release - vfs callback for close 1711 * @inode: inode of tty 1712 * @filp: file pointer for handle to tty 1713 * 1714 * Called the last time each file handle is closed that references this tty. 1715 * There may however be several such references. 1716 * 1717 * Locking: 1718 * Takes BKL. See tty_release_dev(). 1719 * 1720 * Even releasing the tty structures is a tricky business. We have to be very 1721 * careful that the structures are all released at the same time, as interrupts 1722 * might otherwise get the wrong pointers. 1723 * 1724 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could 1725 * lead to double frees or releasing memory still in use. 1726 */ 1727 int tty_release(struct inode *inode, struct file *filp) 1728 { 1729 struct tty_struct *tty = file_tty(filp); 1730 struct tty_struct *o_tty = NULL; 1731 int do_sleep, final; 1732 int idx; 1733 long timeout = 0; 1734 int once = 1; 1735 1736 if (tty_paranoia_check(tty, inode, __func__)) 1737 return 0; 1738 1739 tty_lock(tty); 1740 check_tty_count(tty, __func__); 1741 1742 __tty_fasync(-1, filp, 0); 1743 1744 idx = tty->index; 1745 if (tty->driver->type == TTY_DRIVER_TYPE_PTY && 1746 tty->driver->subtype == PTY_TYPE_MASTER) 1747 o_tty = tty->link; 1748 1749 if (tty_release_checks(tty, idx)) { 1750 tty_unlock(tty); 1751 return 0; 1752 } 1753 1754 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count); 1755 1756 if (tty->ops->close) 1757 tty->ops->close(tty, filp); 1758 1759 /* If tty is pty master, lock the slave pty (stable lock order) */ 1760 tty_lock_slave(o_tty); 1761 1762 /* 1763 * Sanity check: if tty->count is going to zero, there shouldn't be 1764 * any waiters on tty->read_wait or tty->write_wait. We test the 1765 * wait queues and kick everyone out _before_ actually starting to 1766 * close. This ensures that we won't block while releasing the tty 1767 * structure. 1768 * 1769 * The test for the o_tty closing is necessary, since the master and 1770 * slave sides may close in any order. If the slave side closes out 1771 * first, its count will be one, since the master side holds an open. 1772 * Thus this test wouldn't be triggered at the time the slave closed, 1773 * so we do it now. 1774 */ 1775 while (1) { 1776 do_sleep = 0; 1777 1778 if (tty->count <= 1) { 1779 if (waitqueue_active(&tty->read_wait)) { 1780 wake_up_poll(&tty->read_wait, EPOLLIN); 1781 do_sleep++; 1782 } 1783 if (waitqueue_active(&tty->write_wait)) { 1784 wake_up_poll(&tty->write_wait, EPOLLOUT); 1785 do_sleep++; 1786 } 1787 } 1788 if (o_tty && o_tty->count <= 1) { 1789 if (waitqueue_active(&o_tty->read_wait)) { 1790 wake_up_poll(&o_tty->read_wait, EPOLLIN); 1791 do_sleep++; 1792 } 1793 if (waitqueue_active(&o_tty->write_wait)) { 1794 wake_up_poll(&o_tty->write_wait, EPOLLOUT); 1795 do_sleep++; 1796 } 1797 } 1798 if (!do_sleep) 1799 break; 1800 1801 if (once) { 1802 once = 0; 1803 tty_warn(tty, "read/write wait queue active!\n"); 1804 } 1805 schedule_timeout_killable(timeout); 1806 if (timeout < 120 * HZ) 1807 timeout = 2 * timeout + 1; 1808 else 1809 timeout = MAX_SCHEDULE_TIMEOUT; 1810 } 1811 1812 if (o_tty) { 1813 if (--o_tty->count < 0) { 1814 tty_warn(tty, "bad slave count (%d)\n", o_tty->count); 1815 o_tty->count = 0; 1816 } 1817 } 1818 if (--tty->count < 0) { 1819 tty_warn(tty, "bad tty->count (%d)\n", tty->count); 1820 tty->count = 0; 1821 } 1822 1823 /* 1824 * We've decremented tty->count, so we need to remove this file 1825 * descriptor off the tty->tty_files list; this serves two 1826 * purposes: 1827 * - check_tty_count sees the correct number of file descriptors 1828 * associated with this tty. 1829 * - do_tty_hangup no longer sees this file descriptor as 1830 * something that needs to be handled for hangups. 1831 */ 1832 tty_del_file(filp); 1833 1834 /* 1835 * Perform some housekeeping before deciding whether to return. 1836 * 1837 * If _either_ side is closing, make sure there aren't any 1838 * processes that still think tty or o_tty is their controlling 1839 * tty. 1840 */ 1841 if (!tty->count) { 1842 read_lock(&tasklist_lock); 1843 session_clear_tty(tty->ctrl.session); 1844 if (o_tty) 1845 session_clear_tty(o_tty->ctrl.session); 1846 read_unlock(&tasklist_lock); 1847 } 1848 1849 /* check whether both sides are closing ... */ 1850 final = !tty->count && !(o_tty && o_tty->count); 1851 1852 tty_unlock_slave(o_tty); 1853 tty_unlock(tty); 1854 1855 /* At this point, the tty->count == 0 should ensure a dead tty 1856 * cannot be re-opened by a racing opener. 1857 */ 1858 1859 if (!final) 1860 return 0; 1861 1862 tty_debug_hangup(tty, "final close\n"); 1863 1864 tty_release_struct(tty, idx); 1865 return 0; 1866 } 1867 1868 /** 1869 * tty_open_current_tty - get locked tty of current task 1870 * @device: device number 1871 * @filp: file pointer to tty 1872 * @return: locked tty of the current task iff @device is /dev/tty 1873 * 1874 * Performs a re-open of the current task's controlling tty. 1875 * 1876 * We cannot return driver and index like for the other nodes because devpts 1877 * will not work then. It expects inodes to be from devpts FS. 1878 */ 1879 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp) 1880 { 1881 struct tty_struct *tty; 1882 int retval; 1883 1884 if (device != MKDEV(TTYAUX_MAJOR, 0)) 1885 return NULL; 1886 1887 tty = get_current_tty(); 1888 if (!tty) 1889 return ERR_PTR(-ENXIO); 1890 1891 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ 1892 /* noctty = 1; */ 1893 tty_lock(tty); 1894 tty_kref_put(tty); /* safe to drop the kref now */ 1895 1896 retval = tty_reopen(tty); 1897 if (retval < 0) { 1898 tty_unlock(tty); 1899 tty = ERR_PTR(retval); 1900 } 1901 return tty; 1902 } 1903 1904 /** 1905 * tty_lookup_driver - lookup a tty driver for a given device file 1906 * @device: device number 1907 * @filp: file pointer to tty 1908 * @index: index for the device in the @return driver 1909 * 1910 * If returned value is not erroneous, the caller is responsible to decrement 1911 * the refcount by tty_driver_kref_put(). 1912 * 1913 * Locking: %tty_mutex protects get_tty_driver() 1914 * 1915 * Return: driver for this inode (with increased refcount) 1916 */ 1917 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp, 1918 int *index) 1919 { 1920 struct tty_driver *driver = NULL; 1921 1922 switch (device) { 1923 #ifdef CONFIG_VT 1924 case MKDEV(TTY_MAJOR, 0): { 1925 extern struct tty_driver *console_driver; 1926 1927 driver = tty_driver_kref_get(console_driver); 1928 *index = fg_console; 1929 break; 1930 } 1931 #endif 1932 case MKDEV(TTYAUX_MAJOR, 1): { 1933 struct tty_driver *console_driver = console_device(index); 1934 1935 if (console_driver) { 1936 driver = tty_driver_kref_get(console_driver); 1937 if (driver && filp) { 1938 /* Don't let /dev/console block */ 1939 filp->f_flags |= O_NONBLOCK; 1940 break; 1941 } 1942 } 1943 if (driver) 1944 tty_driver_kref_put(driver); 1945 return ERR_PTR(-ENODEV); 1946 } 1947 default: 1948 driver = get_tty_driver(device, index); 1949 if (!driver) 1950 return ERR_PTR(-ENODEV); 1951 break; 1952 } 1953 return driver; 1954 } 1955 1956 static struct tty_struct *tty_kopen(dev_t device, int shared) 1957 { 1958 struct tty_struct *tty; 1959 struct tty_driver *driver; 1960 int index = -1; 1961 1962 mutex_lock(&tty_mutex); 1963 driver = tty_lookup_driver(device, NULL, &index); 1964 if (IS_ERR(driver)) { 1965 mutex_unlock(&tty_mutex); 1966 return ERR_CAST(driver); 1967 } 1968 1969 /* check whether we're reopening an existing tty */ 1970 tty = tty_driver_lookup_tty(driver, NULL, index); 1971 if (IS_ERR(tty) || shared) 1972 goto out; 1973 1974 if (tty) { 1975 /* drop kref from tty_driver_lookup_tty() */ 1976 tty_kref_put(tty); 1977 tty = ERR_PTR(-EBUSY); 1978 } else { /* tty_init_dev returns tty with the tty_lock held */ 1979 tty = tty_init_dev(driver, index); 1980 if (IS_ERR(tty)) 1981 goto out; 1982 tty_port_set_kopened(tty->port, 1); 1983 } 1984 out: 1985 mutex_unlock(&tty_mutex); 1986 tty_driver_kref_put(driver); 1987 return tty; 1988 } 1989 1990 /** 1991 * tty_kopen_exclusive - open a tty device for kernel 1992 * @device: dev_t of device to open 1993 * 1994 * Opens tty exclusively for kernel. Performs the driver lookup, makes sure 1995 * it's not already opened and performs the first-time tty initialization. 1996 * 1997 * Claims the global %tty_mutex to serialize: 1998 * * concurrent first-time tty initialization 1999 * * concurrent tty driver removal w/ lookup 2000 * * concurrent tty removal from driver table 2001 * 2002 * Return: the locked initialized &tty_struct 2003 */ 2004 struct tty_struct *tty_kopen_exclusive(dev_t device) 2005 { 2006 return tty_kopen(device, 0); 2007 } 2008 EXPORT_SYMBOL_GPL(tty_kopen_exclusive); 2009 2010 /** 2011 * tty_kopen_shared - open a tty device for shared in-kernel use 2012 * @device: dev_t of device to open 2013 * 2014 * Opens an already existing tty for in-kernel use. Compared to 2015 * tty_kopen_exclusive() above it doesn't ensure to be the only user. 2016 * 2017 * Locking: identical to tty_kopen() above. 2018 */ 2019 struct tty_struct *tty_kopen_shared(dev_t device) 2020 { 2021 return tty_kopen(device, 1); 2022 } 2023 EXPORT_SYMBOL_GPL(tty_kopen_shared); 2024 2025 /** 2026 * tty_open_by_driver - open a tty device 2027 * @device: dev_t of device to open 2028 * @filp: file pointer to tty 2029 * 2030 * Performs the driver lookup, checks for a reopen, or otherwise performs the 2031 * first-time tty initialization. 2032 * 2033 * 2034 * Claims the global tty_mutex to serialize: 2035 * * concurrent first-time tty initialization 2036 * * concurrent tty driver removal w/ lookup 2037 * * concurrent tty removal from driver table 2038 * 2039 * Return: the locked initialized or re-opened &tty_struct 2040 */ 2041 static struct tty_struct *tty_open_by_driver(dev_t device, 2042 struct file *filp) 2043 { 2044 struct tty_struct *tty; 2045 struct tty_driver *driver = NULL; 2046 int index = -1; 2047 int retval; 2048 2049 mutex_lock(&tty_mutex); 2050 driver = tty_lookup_driver(device, filp, &index); 2051 if (IS_ERR(driver)) { 2052 mutex_unlock(&tty_mutex); 2053 return ERR_CAST(driver); 2054 } 2055 2056 /* check whether we're reopening an existing tty */ 2057 tty = tty_driver_lookup_tty(driver, filp, index); 2058 if (IS_ERR(tty)) { 2059 mutex_unlock(&tty_mutex); 2060 goto out; 2061 } 2062 2063 if (tty) { 2064 if (tty_port_kopened(tty->port)) { 2065 tty_kref_put(tty); 2066 mutex_unlock(&tty_mutex); 2067 tty = ERR_PTR(-EBUSY); 2068 goto out; 2069 } 2070 mutex_unlock(&tty_mutex); 2071 retval = tty_lock_interruptible(tty); 2072 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */ 2073 if (retval) { 2074 if (retval == -EINTR) 2075 retval = -ERESTARTSYS; 2076 tty = ERR_PTR(retval); 2077 goto out; 2078 } 2079 retval = tty_reopen(tty); 2080 if (retval < 0) { 2081 tty_unlock(tty); 2082 tty = ERR_PTR(retval); 2083 } 2084 } else { /* Returns with the tty_lock held for now */ 2085 tty = tty_init_dev(driver, index); 2086 mutex_unlock(&tty_mutex); 2087 } 2088 out: 2089 tty_driver_kref_put(driver); 2090 return tty; 2091 } 2092 2093 /** 2094 * tty_open - open a tty device 2095 * @inode: inode of device file 2096 * @filp: file pointer to tty 2097 * 2098 * tty_open() and tty_release() keep up the tty count that contains the number 2099 * of opens done on a tty. We cannot use the inode-count, as different inodes 2100 * might point to the same tty. 2101 * 2102 * Open-counting is needed for pty masters, as well as for keeping track of 2103 * serial lines: DTR is dropped when the last close happens. 2104 * (This is not done solely through tty->count, now. - Ted 1/27/92) 2105 * 2106 * The termios state of a pty is reset on the first open so that settings don't 2107 * persist across reuse. 2108 * 2109 * Locking: 2110 * * %tty_mutex protects tty, tty_lookup_driver() and tty_init_dev(). 2111 * * @tty->count should protect the rest. 2112 * * ->siglock protects ->signal/->sighand 2113 * 2114 * Note: the tty_unlock/lock cases without a ref are only safe due to %tty_mutex 2115 */ 2116 static int tty_open(struct inode *inode, struct file *filp) 2117 { 2118 struct tty_struct *tty; 2119 int noctty, retval; 2120 dev_t device = inode->i_rdev; 2121 unsigned saved_flags = filp->f_flags; 2122 2123 nonseekable_open(inode, filp); 2124 2125 retry_open: 2126 retval = tty_alloc_file(filp); 2127 if (retval) 2128 return -ENOMEM; 2129 2130 tty = tty_open_current_tty(device, filp); 2131 if (!tty) 2132 tty = tty_open_by_driver(device, filp); 2133 2134 if (IS_ERR(tty)) { 2135 tty_free_file(filp); 2136 retval = PTR_ERR(tty); 2137 if (retval != -EAGAIN || signal_pending(current)) 2138 return retval; 2139 schedule(); 2140 goto retry_open; 2141 } 2142 2143 tty_add_file(tty, filp); 2144 2145 check_tty_count(tty, __func__); 2146 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count); 2147 2148 if (tty->ops->open) 2149 retval = tty->ops->open(tty, filp); 2150 else 2151 retval = -ENODEV; 2152 filp->f_flags = saved_flags; 2153 2154 if (retval) { 2155 tty_debug_hangup(tty, "open error %d, releasing\n", retval); 2156 2157 tty_unlock(tty); /* need to call tty_release without BTM */ 2158 tty_release(inode, filp); 2159 if (retval != -ERESTARTSYS) 2160 return retval; 2161 2162 if (signal_pending(current)) 2163 return retval; 2164 2165 schedule(); 2166 /* 2167 * Need to reset f_op in case a hangup happened. 2168 */ 2169 if (tty_hung_up_p(filp)) 2170 filp->f_op = &tty_fops; 2171 goto retry_open; 2172 } 2173 clear_bit(TTY_HUPPED, &tty->flags); 2174 2175 noctty = (filp->f_flags & O_NOCTTY) || 2176 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) || 2177 device == MKDEV(TTYAUX_MAJOR, 1) || 2178 (tty->driver->type == TTY_DRIVER_TYPE_PTY && 2179 tty->driver->subtype == PTY_TYPE_MASTER); 2180 if (!noctty) 2181 tty_open_proc_set_tty(filp, tty); 2182 tty_unlock(tty); 2183 return 0; 2184 } 2185 2186 2187 /** 2188 * tty_poll - check tty status 2189 * @filp: file being polled 2190 * @wait: poll wait structures to update 2191 * 2192 * Call the line discipline polling method to obtain the poll status of the 2193 * device. 2194 * 2195 * Locking: locks called line discipline but ldisc poll method may be 2196 * re-entered freely by other callers. 2197 */ 2198 static __poll_t tty_poll(struct file *filp, poll_table *wait) 2199 { 2200 struct tty_struct *tty = file_tty(filp); 2201 struct tty_ldisc *ld; 2202 __poll_t ret = 0; 2203 2204 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll")) 2205 return 0; 2206 2207 ld = tty_ldisc_ref_wait(tty); 2208 if (!ld) 2209 return hung_up_tty_poll(filp, wait); 2210 if (ld->ops->poll) 2211 ret = ld->ops->poll(tty, filp, wait); 2212 tty_ldisc_deref(ld); 2213 return ret; 2214 } 2215 2216 static int __tty_fasync(int fd, struct file *filp, int on) 2217 { 2218 struct tty_struct *tty = file_tty(filp); 2219 unsigned long flags; 2220 int retval = 0; 2221 2222 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync")) 2223 goto out; 2224 2225 retval = fasync_helper(fd, filp, on, &tty->fasync); 2226 if (retval <= 0) 2227 goto out; 2228 2229 if (on) { 2230 enum pid_type type; 2231 struct pid *pid; 2232 2233 spin_lock_irqsave(&tty->ctrl.lock, flags); 2234 if (tty->ctrl.pgrp) { 2235 pid = tty->ctrl.pgrp; 2236 type = PIDTYPE_PGID; 2237 } else { 2238 pid = task_pid(current); 2239 type = PIDTYPE_TGID; 2240 } 2241 get_pid(pid); 2242 spin_unlock_irqrestore(&tty->ctrl.lock, flags); 2243 __f_setown(filp, pid, type, 0); 2244 put_pid(pid); 2245 retval = 0; 2246 } 2247 out: 2248 return retval; 2249 } 2250 2251 static int tty_fasync(int fd, struct file *filp, int on) 2252 { 2253 struct tty_struct *tty = file_tty(filp); 2254 int retval = -ENOTTY; 2255 2256 tty_lock(tty); 2257 if (!tty_hung_up_p(filp)) 2258 retval = __tty_fasync(fd, filp, on); 2259 tty_unlock(tty); 2260 2261 return retval; 2262 } 2263 2264 static bool tty_legacy_tiocsti __read_mostly = IS_ENABLED(CONFIG_LEGACY_TIOCSTI); 2265 /** 2266 * tiocsti - fake input character 2267 * @tty: tty to fake input into 2268 * @p: pointer to character 2269 * 2270 * Fake input to a tty device. Does the necessary locking and input management. 2271 * 2272 * FIXME: does not honour flow control ?? 2273 * 2274 * Locking: 2275 * * Called functions take tty_ldiscs_lock 2276 * * current->signal->tty check is safe without locks 2277 */ 2278 static int tiocsti(struct tty_struct *tty, char __user *p) 2279 { 2280 char ch, mbz = 0; 2281 struct tty_ldisc *ld; 2282 2283 if (!tty_legacy_tiocsti && !capable(CAP_SYS_ADMIN)) 2284 return -EIO; 2285 2286 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) 2287 return -EPERM; 2288 if (get_user(ch, p)) 2289 return -EFAULT; 2290 tty_audit_tiocsti(tty, ch); 2291 ld = tty_ldisc_ref_wait(tty); 2292 if (!ld) 2293 return -EIO; 2294 tty_buffer_lock_exclusive(tty->port); 2295 if (ld->ops->receive_buf) 2296 ld->ops->receive_buf(tty, &ch, &mbz, 1); 2297 tty_buffer_unlock_exclusive(tty->port); 2298 tty_ldisc_deref(ld); 2299 return 0; 2300 } 2301 2302 /** 2303 * tiocgwinsz - implement window query ioctl 2304 * @tty: tty 2305 * @arg: user buffer for result 2306 * 2307 * Copies the kernel idea of the window size into the user buffer. 2308 * 2309 * Locking: @tty->winsize_mutex is taken to ensure the winsize data is 2310 * consistent. 2311 */ 2312 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg) 2313 { 2314 int err; 2315 2316 mutex_lock(&tty->winsize_mutex); 2317 err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); 2318 mutex_unlock(&tty->winsize_mutex); 2319 2320 return err ? -EFAULT : 0; 2321 } 2322 2323 /** 2324 * tty_do_resize - resize event 2325 * @tty: tty being resized 2326 * @ws: new dimensions 2327 * 2328 * Update the termios variables and send the necessary signals to peform a 2329 * terminal resize correctly. 2330 */ 2331 int tty_do_resize(struct tty_struct *tty, struct winsize *ws) 2332 { 2333 struct pid *pgrp; 2334 2335 /* Lock the tty */ 2336 mutex_lock(&tty->winsize_mutex); 2337 if (!memcmp(ws, &tty->winsize, sizeof(*ws))) 2338 goto done; 2339 2340 /* Signal the foreground process group */ 2341 pgrp = tty_get_pgrp(tty); 2342 if (pgrp) 2343 kill_pgrp(pgrp, SIGWINCH, 1); 2344 put_pid(pgrp); 2345 2346 tty->winsize = *ws; 2347 done: 2348 mutex_unlock(&tty->winsize_mutex); 2349 return 0; 2350 } 2351 EXPORT_SYMBOL(tty_do_resize); 2352 2353 /** 2354 * tiocswinsz - implement window size set ioctl 2355 * @tty: tty side of tty 2356 * @arg: user buffer for result 2357 * 2358 * Copies the user idea of the window size to the kernel. Traditionally this is 2359 * just advisory information but for the Linux console it actually has driver 2360 * level meaning and triggers a VC resize. 2361 * 2362 * Locking: 2363 * Driver dependent. The default do_resize method takes the tty termios 2364 * mutex and ctrl.lock. The console takes its own lock then calls into the 2365 * default method. 2366 */ 2367 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg) 2368 { 2369 struct winsize tmp_ws; 2370 2371 if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) 2372 return -EFAULT; 2373 2374 if (tty->ops->resize) 2375 return tty->ops->resize(tty, &tmp_ws); 2376 else 2377 return tty_do_resize(tty, &tmp_ws); 2378 } 2379 2380 /** 2381 * tioccons - allow admin to move logical console 2382 * @file: the file to become console 2383 * 2384 * Allow the administrator to move the redirected console device. 2385 * 2386 * Locking: uses redirect_lock to guard the redirect information 2387 */ 2388 static int tioccons(struct file *file) 2389 { 2390 if (!capable(CAP_SYS_ADMIN)) 2391 return -EPERM; 2392 if (file->f_op->write_iter == redirected_tty_write) { 2393 struct file *f; 2394 2395 spin_lock(&redirect_lock); 2396 f = redirect; 2397 redirect = NULL; 2398 spin_unlock(&redirect_lock); 2399 if (f) 2400 fput(f); 2401 return 0; 2402 } 2403 if (file->f_op->write_iter != tty_write) 2404 return -ENOTTY; 2405 if (!(file->f_mode & FMODE_WRITE)) 2406 return -EBADF; 2407 if (!(file->f_mode & FMODE_CAN_WRITE)) 2408 return -EINVAL; 2409 spin_lock(&redirect_lock); 2410 if (redirect) { 2411 spin_unlock(&redirect_lock); 2412 return -EBUSY; 2413 } 2414 redirect = get_file(file); 2415 spin_unlock(&redirect_lock); 2416 return 0; 2417 } 2418 2419 /** 2420 * tiocsetd - set line discipline 2421 * @tty: tty device 2422 * @p: pointer to user data 2423 * 2424 * Set the line discipline according to user request. 2425 * 2426 * Locking: see tty_set_ldisc(), this function is just a helper 2427 */ 2428 static int tiocsetd(struct tty_struct *tty, int __user *p) 2429 { 2430 int disc; 2431 int ret; 2432 2433 if (get_user(disc, p)) 2434 return -EFAULT; 2435 2436 ret = tty_set_ldisc(tty, disc); 2437 2438 return ret; 2439 } 2440 2441 /** 2442 * tiocgetd - get line discipline 2443 * @tty: tty device 2444 * @p: pointer to user data 2445 * 2446 * Retrieves the line discipline id directly from the ldisc. 2447 * 2448 * Locking: waits for ldisc reference (in case the line discipline is changing 2449 * or the @tty is being hungup) 2450 */ 2451 static int tiocgetd(struct tty_struct *tty, int __user *p) 2452 { 2453 struct tty_ldisc *ld; 2454 int ret; 2455 2456 ld = tty_ldisc_ref_wait(tty); 2457 if (!ld) 2458 return -EIO; 2459 ret = put_user(ld->ops->num, p); 2460 tty_ldisc_deref(ld); 2461 return ret; 2462 } 2463 2464 /** 2465 * send_break - performed time break 2466 * @tty: device to break on 2467 * @duration: timeout in mS 2468 * 2469 * Perform a timed break on hardware that lacks its own driver level timed 2470 * break functionality. 2471 * 2472 * Locking: 2473 * @tty->atomic_write_lock serializes 2474 */ 2475 static int send_break(struct tty_struct *tty, unsigned int duration) 2476 { 2477 int retval; 2478 2479 if (tty->ops->break_ctl == NULL) 2480 return 0; 2481 2482 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK) 2483 retval = tty->ops->break_ctl(tty, duration); 2484 else { 2485 /* Do the work ourselves */ 2486 if (tty_write_lock(tty, false) < 0) 2487 return -EINTR; 2488 retval = tty->ops->break_ctl(tty, -1); 2489 if (retval) 2490 goto out; 2491 if (!signal_pending(current)) 2492 msleep_interruptible(duration); 2493 retval = tty->ops->break_ctl(tty, 0); 2494 out: 2495 tty_write_unlock(tty); 2496 if (signal_pending(current)) 2497 retval = -EINTR; 2498 } 2499 return retval; 2500 } 2501 2502 /** 2503 * tty_tiocmget - get modem status 2504 * @tty: tty device 2505 * @p: pointer to result 2506 * 2507 * Obtain the modem status bits from the tty driver if the feature is 2508 * supported. Return -%ENOTTY if it is not available. 2509 * 2510 * Locking: none (up to the driver) 2511 */ 2512 static int tty_tiocmget(struct tty_struct *tty, int __user *p) 2513 { 2514 int retval = -ENOTTY; 2515 2516 if (tty->ops->tiocmget) { 2517 retval = tty->ops->tiocmget(tty); 2518 2519 if (retval >= 0) 2520 retval = put_user(retval, p); 2521 } 2522 return retval; 2523 } 2524 2525 /** 2526 * tty_tiocmset - set modem status 2527 * @tty: tty device 2528 * @cmd: command - clear bits, set bits or set all 2529 * @p: pointer to desired bits 2530 * 2531 * Set the modem status bits from the tty driver if the feature 2532 * is supported. Return -%ENOTTY if it is not available. 2533 * 2534 * Locking: none (up to the driver) 2535 */ 2536 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd, 2537 unsigned __user *p) 2538 { 2539 int retval; 2540 unsigned int set, clear, val; 2541 2542 if (tty->ops->tiocmset == NULL) 2543 return -ENOTTY; 2544 2545 retval = get_user(val, p); 2546 if (retval) 2547 return retval; 2548 set = clear = 0; 2549 switch (cmd) { 2550 case TIOCMBIS: 2551 set = val; 2552 break; 2553 case TIOCMBIC: 2554 clear = val; 2555 break; 2556 case TIOCMSET: 2557 set = val; 2558 clear = ~val; 2559 break; 2560 } 2561 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; 2562 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; 2563 return tty->ops->tiocmset(tty, set, clear); 2564 } 2565 2566 /** 2567 * tty_get_icount - get tty statistics 2568 * @tty: tty device 2569 * @icount: output parameter 2570 * 2571 * Gets a copy of the @tty's icount statistics. 2572 * 2573 * Locking: none (up to the driver) 2574 */ 2575 int tty_get_icount(struct tty_struct *tty, 2576 struct serial_icounter_struct *icount) 2577 { 2578 memset(icount, 0, sizeof(*icount)); 2579 2580 if (tty->ops->get_icount) 2581 return tty->ops->get_icount(tty, icount); 2582 else 2583 return -ENOTTY; 2584 } 2585 EXPORT_SYMBOL_GPL(tty_get_icount); 2586 2587 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg) 2588 { 2589 struct serial_icounter_struct icount; 2590 int retval; 2591 2592 retval = tty_get_icount(tty, &icount); 2593 if (retval != 0) 2594 return retval; 2595 2596 if (copy_to_user(arg, &icount, sizeof(icount))) 2597 return -EFAULT; 2598 return 0; 2599 } 2600 2601 static int tty_set_serial(struct tty_struct *tty, struct serial_struct *ss) 2602 { 2603 char comm[TASK_COMM_LEN]; 2604 int flags; 2605 2606 flags = ss->flags & ASYNC_DEPRECATED; 2607 2608 if (flags) 2609 pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n", 2610 __func__, get_task_comm(comm, current), flags); 2611 2612 if (!tty->ops->set_serial) 2613 return -ENOTTY; 2614 2615 return tty->ops->set_serial(tty, ss); 2616 } 2617 2618 static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss) 2619 { 2620 struct serial_struct v; 2621 2622 if (copy_from_user(&v, ss, sizeof(*ss))) 2623 return -EFAULT; 2624 2625 return tty_set_serial(tty, &v); 2626 } 2627 2628 static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss) 2629 { 2630 struct serial_struct v; 2631 int err; 2632 2633 memset(&v, 0, sizeof(v)); 2634 if (!tty->ops->get_serial) 2635 return -ENOTTY; 2636 err = tty->ops->get_serial(tty, &v); 2637 if (!err && copy_to_user(ss, &v, sizeof(v))) 2638 err = -EFAULT; 2639 return err; 2640 } 2641 2642 /* 2643 * if pty, return the slave side (real_tty) 2644 * otherwise, return self 2645 */ 2646 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty) 2647 { 2648 if (tty->driver->type == TTY_DRIVER_TYPE_PTY && 2649 tty->driver->subtype == PTY_TYPE_MASTER) 2650 tty = tty->link; 2651 return tty; 2652 } 2653 2654 /* 2655 * Split this up, as gcc can choke on it otherwise.. 2656 */ 2657 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2658 { 2659 struct tty_struct *tty = file_tty(file); 2660 struct tty_struct *real_tty; 2661 void __user *p = (void __user *)arg; 2662 int retval; 2663 struct tty_ldisc *ld; 2664 2665 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl")) 2666 return -EINVAL; 2667 2668 real_tty = tty_pair_get_tty(tty); 2669 2670 /* 2671 * Factor out some common prep work 2672 */ 2673 switch (cmd) { 2674 case TIOCSETD: 2675 case TIOCSBRK: 2676 case TIOCCBRK: 2677 case TCSBRK: 2678 case TCSBRKP: 2679 retval = tty_check_change(tty); 2680 if (retval) 2681 return retval; 2682 if (cmd != TIOCCBRK) { 2683 tty_wait_until_sent(tty, 0); 2684 if (signal_pending(current)) 2685 return -EINTR; 2686 } 2687 break; 2688 } 2689 2690 /* 2691 * Now do the stuff. 2692 */ 2693 switch (cmd) { 2694 case TIOCSTI: 2695 return tiocsti(tty, p); 2696 case TIOCGWINSZ: 2697 return tiocgwinsz(real_tty, p); 2698 case TIOCSWINSZ: 2699 return tiocswinsz(real_tty, p); 2700 case TIOCCONS: 2701 return real_tty != tty ? -EINVAL : tioccons(file); 2702 case TIOCEXCL: 2703 set_bit(TTY_EXCLUSIVE, &tty->flags); 2704 return 0; 2705 case TIOCNXCL: 2706 clear_bit(TTY_EXCLUSIVE, &tty->flags); 2707 return 0; 2708 case TIOCGEXCL: 2709 { 2710 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags); 2711 2712 return put_user(excl, (int __user *)p); 2713 } 2714 case TIOCGETD: 2715 return tiocgetd(tty, p); 2716 case TIOCSETD: 2717 return tiocsetd(tty, p); 2718 case TIOCVHANGUP: 2719 if (!capable(CAP_SYS_ADMIN)) 2720 return -EPERM; 2721 tty_vhangup(tty); 2722 return 0; 2723 case TIOCGDEV: 2724 { 2725 unsigned int ret = new_encode_dev(tty_devnum(real_tty)); 2726 2727 return put_user(ret, (unsigned int __user *)p); 2728 } 2729 /* 2730 * Break handling 2731 */ 2732 case TIOCSBRK: /* Turn break on, unconditionally */ 2733 if (tty->ops->break_ctl) 2734 return tty->ops->break_ctl(tty, -1); 2735 return 0; 2736 case TIOCCBRK: /* Turn break off, unconditionally */ 2737 if (tty->ops->break_ctl) 2738 return tty->ops->break_ctl(tty, 0); 2739 return 0; 2740 case TCSBRK: /* SVID version: non-zero arg --> no break */ 2741 /* non-zero arg means wait for all output data 2742 * to be sent (performed above) but don't send break. 2743 * This is used by the tcdrain() termios function. 2744 */ 2745 if (!arg) 2746 return send_break(tty, 250); 2747 return 0; 2748 case TCSBRKP: /* support for POSIX tcsendbreak() */ 2749 return send_break(tty, arg ? arg*100 : 250); 2750 2751 case TIOCMGET: 2752 return tty_tiocmget(tty, p); 2753 case TIOCMSET: 2754 case TIOCMBIC: 2755 case TIOCMBIS: 2756 return tty_tiocmset(tty, cmd, p); 2757 case TIOCGICOUNT: 2758 return tty_tiocgicount(tty, p); 2759 case TCFLSH: 2760 switch (arg) { 2761 case TCIFLUSH: 2762 case TCIOFLUSH: 2763 /* flush tty buffer and allow ldisc to process ioctl */ 2764 tty_buffer_flush(tty, NULL); 2765 break; 2766 } 2767 break; 2768 case TIOCSSERIAL: 2769 return tty_tiocsserial(tty, p); 2770 case TIOCGSERIAL: 2771 return tty_tiocgserial(tty, p); 2772 case TIOCGPTPEER: 2773 /* Special because the struct file is needed */ 2774 return ptm_open_peer(file, tty, (int)arg); 2775 default: 2776 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg); 2777 if (retval != -ENOIOCTLCMD) 2778 return retval; 2779 } 2780 if (tty->ops->ioctl) { 2781 retval = tty->ops->ioctl(tty, cmd, arg); 2782 if (retval != -ENOIOCTLCMD) 2783 return retval; 2784 } 2785 ld = tty_ldisc_ref_wait(tty); 2786 if (!ld) 2787 return hung_up_tty_ioctl(file, cmd, arg); 2788 retval = -EINVAL; 2789 if (ld->ops->ioctl) { 2790 retval = ld->ops->ioctl(tty, cmd, arg); 2791 if (retval == -ENOIOCTLCMD) 2792 retval = -ENOTTY; 2793 } 2794 tty_ldisc_deref(ld); 2795 return retval; 2796 } 2797 2798 #ifdef CONFIG_COMPAT 2799 2800 struct serial_struct32 { 2801 compat_int_t type; 2802 compat_int_t line; 2803 compat_uint_t port; 2804 compat_int_t irq; 2805 compat_int_t flags; 2806 compat_int_t xmit_fifo_size; 2807 compat_int_t custom_divisor; 2808 compat_int_t baud_base; 2809 unsigned short close_delay; 2810 char io_type; 2811 char reserved_char; 2812 compat_int_t hub6; 2813 unsigned short closing_wait; /* time to wait before closing */ 2814 unsigned short closing_wait2; /* no longer used... */ 2815 compat_uint_t iomem_base; 2816 unsigned short iomem_reg_shift; 2817 unsigned int port_high; 2818 /* compat_ulong_t iomap_base FIXME */ 2819 compat_int_t reserved; 2820 }; 2821 2822 static int compat_tty_tiocsserial(struct tty_struct *tty, 2823 struct serial_struct32 __user *ss) 2824 { 2825 struct serial_struct32 v32; 2826 struct serial_struct v; 2827 2828 if (copy_from_user(&v32, ss, sizeof(*ss))) 2829 return -EFAULT; 2830 2831 memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base)); 2832 v.iomem_base = compat_ptr(v32.iomem_base); 2833 v.iomem_reg_shift = v32.iomem_reg_shift; 2834 v.port_high = v32.port_high; 2835 v.iomap_base = 0; 2836 2837 return tty_set_serial(tty, &v); 2838 } 2839 2840 static int compat_tty_tiocgserial(struct tty_struct *tty, 2841 struct serial_struct32 __user *ss) 2842 { 2843 struct serial_struct32 v32; 2844 struct serial_struct v; 2845 int err; 2846 2847 memset(&v, 0, sizeof(v)); 2848 memset(&v32, 0, sizeof(v32)); 2849 2850 if (!tty->ops->get_serial) 2851 return -ENOTTY; 2852 err = tty->ops->get_serial(tty, &v); 2853 if (!err) { 2854 memcpy(&v32, &v, offsetof(struct serial_struct32, iomem_base)); 2855 v32.iomem_base = (unsigned long)v.iomem_base >> 32 ? 2856 0xfffffff : ptr_to_compat(v.iomem_base); 2857 v32.iomem_reg_shift = v.iomem_reg_shift; 2858 v32.port_high = v.port_high; 2859 if (copy_to_user(ss, &v32, sizeof(v32))) 2860 err = -EFAULT; 2861 } 2862 return err; 2863 } 2864 static long tty_compat_ioctl(struct file *file, unsigned int cmd, 2865 unsigned long arg) 2866 { 2867 struct tty_struct *tty = file_tty(file); 2868 struct tty_ldisc *ld; 2869 int retval = -ENOIOCTLCMD; 2870 2871 switch (cmd) { 2872 case TIOCOUTQ: 2873 case TIOCSTI: 2874 case TIOCGWINSZ: 2875 case TIOCSWINSZ: 2876 case TIOCGEXCL: 2877 case TIOCGETD: 2878 case TIOCSETD: 2879 case TIOCGDEV: 2880 case TIOCMGET: 2881 case TIOCMSET: 2882 case TIOCMBIC: 2883 case TIOCMBIS: 2884 case TIOCGICOUNT: 2885 case TIOCGPGRP: 2886 case TIOCSPGRP: 2887 case TIOCGSID: 2888 case TIOCSERGETLSR: 2889 case TIOCGRS485: 2890 case TIOCSRS485: 2891 #ifdef TIOCGETP 2892 case TIOCGETP: 2893 case TIOCSETP: 2894 case TIOCSETN: 2895 #endif 2896 #ifdef TIOCGETC 2897 case TIOCGETC: 2898 case TIOCSETC: 2899 #endif 2900 #ifdef TIOCGLTC 2901 case TIOCGLTC: 2902 case TIOCSLTC: 2903 #endif 2904 case TCSETSF: 2905 case TCSETSW: 2906 case TCSETS: 2907 case TCGETS: 2908 #ifdef TCGETS2 2909 case TCGETS2: 2910 case TCSETSF2: 2911 case TCSETSW2: 2912 case TCSETS2: 2913 #endif 2914 case TCGETA: 2915 case TCSETAF: 2916 case TCSETAW: 2917 case TCSETA: 2918 case TIOCGLCKTRMIOS: 2919 case TIOCSLCKTRMIOS: 2920 #ifdef TCGETX 2921 case TCGETX: 2922 case TCSETX: 2923 case TCSETXW: 2924 case TCSETXF: 2925 #endif 2926 case TIOCGSOFTCAR: 2927 case TIOCSSOFTCAR: 2928 2929 case PPPIOCGCHAN: 2930 case PPPIOCGUNIT: 2931 return tty_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 2932 case TIOCCONS: 2933 case TIOCEXCL: 2934 case TIOCNXCL: 2935 case TIOCVHANGUP: 2936 case TIOCSBRK: 2937 case TIOCCBRK: 2938 case TCSBRK: 2939 case TCSBRKP: 2940 case TCFLSH: 2941 case TIOCGPTPEER: 2942 case TIOCNOTTY: 2943 case TIOCSCTTY: 2944 case TCXONC: 2945 case TIOCMIWAIT: 2946 case TIOCSERCONFIG: 2947 return tty_ioctl(file, cmd, arg); 2948 } 2949 2950 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl")) 2951 return -EINVAL; 2952 2953 switch (cmd) { 2954 case TIOCSSERIAL: 2955 return compat_tty_tiocsserial(tty, compat_ptr(arg)); 2956 case TIOCGSERIAL: 2957 return compat_tty_tiocgserial(tty, compat_ptr(arg)); 2958 } 2959 if (tty->ops->compat_ioctl) { 2960 retval = tty->ops->compat_ioctl(tty, cmd, arg); 2961 if (retval != -ENOIOCTLCMD) 2962 return retval; 2963 } 2964 2965 ld = tty_ldisc_ref_wait(tty); 2966 if (!ld) 2967 return hung_up_tty_compat_ioctl(file, cmd, arg); 2968 if (ld->ops->compat_ioctl) 2969 retval = ld->ops->compat_ioctl(tty, cmd, arg); 2970 if (retval == -ENOIOCTLCMD && ld->ops->ioctl) 2971 retval = ld->ops->ioctl(tty, (unsigned long)compat_ptr(cmd), 2972 arg); 2973 tty_ldisc_deref(ld); 2974 2975 return retval; 2976 } 2977 #endif 2978 2979 static int this_tty(const void *t, struct file *file, unsigned fd) 2980 { 2981 if (likely(file->f_op->read_iter != tty_read)) 2982 return 0; 2983 return file_tty(file) != t ? 0 : fd + 1; 2984 } 2985 2986 /* 2987 * This implements the "Secure Attention Key" --- the idea is to 2988 * prevent trojan horses by killing all processes associated with this 2989 * tty when the user hits the "Secure Attention Key". Required for 2990 * super-paranoid applications --- see the Orange Book for more details. 2991 * 2992 * This code could be nicer; ideally it should send a HUP, wait a few 2993 * seconds, then send a INT, and then a KILL signal. But you then 2994 * have to coordinate with the init process, since all processes associated 2995 * with the current tty must be dead before the new getty is allowed 2996 * to spawn. 2997 * 2998 * Now, if it would be correct ;-/ The current code has a nasty hole - 2999 * it doesn't catch files in flight. We may send the descriptor to ourselves 3000 * via AF_UNIX socket, close it and later fetch from socket. FIXME. 3001 * 3002 * Nasty bug: do_SAK is being called in interrupt context. This can 3003 * deadlock. We punt it up to process context. AKPM - 16Mar2001 3004 */ 3005 void __do_SAK(struct tty_struct *tty) 3006 { 3007 struct task_struct *g, *p; 3008 struct pid *session; 3009 int i; 3010 unsigned long flags; 3011 3012 spin_lock_irqsave(&tty->ctrl.lock, flags); 3013 session = get_pid(tty->ctrl.session); 3014 spin_unlock_irqrestore(&tty->ctrl.lock, flags); 3015 3016 tty_ldisc_flush(tty); 3017 3018 tty_driver_flush_buffer(tty); 3019 3020 read_lock(&tasklist_lock); 3021 /* Kill the entire session */ 3022 do_each_pid_task(session, PIDTYPE_SID, p) { 3023 tty_notice(tty, "SAK: killed process %d (%s): by session\n", 3024 task_pid_nr(p), p->comm); 3025 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID); 3026 } while_each_pid_task(session, PIDTYPE_SID, p); 3027 3028 /* Now kill any processes that happen to have the tty open */ 3029 do_each_thread(g, p) { 3030 if (p->signal->tty == tty) { 3031 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n", 3032 task_pid_nr(p), p->comm); 3033 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, 3034 PIDTYPE_SID); 3035 continue; 3036 } 3037 task_lock(p); 3038 i = iterate_fd(p->files, 0, this_tty, tty); 3039 if (i != 0) { 3040 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n", 3041 task_pid_nr(p), p->comm, i - 1); 3042 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, 3043 PIDTYPE_SID); 3044 } 3045 task_unlock(p); 3046 } while_each_thread(g, p); 3047 read_unlock(&tasklist_lock); 3048 put_pid(session); 3049 } 3050 3051 static void do_SAK_work(struct work_struct *work) 3052 { 3053 struct tty_struct *tty = 3054 container_of(work, struct tty_struct, SAK_work); 3055 __do_SAK(tty); 3056 } 3057 3058 /* 3059 * The tq handling here is a little racy - tty->SAK_work may already be queued. 3060 * Fortunately we don't need to worry, because if ->SAK_work is already queued, 3061 * the values which we write to it will be identical to the values which it 3062 * already has. --akpm 3063 */ 3064 void do_SAK(struct tty_struct *tty) 3065 { 3066 if (!tty) 3067 return; 3068 schedule_work(&tty->SAK_work); 3069 } 3070 EXPORT_SYMBOL(do_SAK); 3071 3072 /* Must put_device() after it's unused! */ 3073 static struct device *tty_get_device(struct tty_struct *tty) 3074 { 3075 dev_t devt = tty_devnum(tty); 3076 3077 return class_find_device_by_devt(&tty_class, devt); 3078 } 3079 3080 3081 /** 3082 * alloc_tty_struct - allocate a new tty 3083 * @driver: driver which will handle the returned tty 3084 * @idx: minor of the tty 3085 * 3086 * This subroutine allocates and initializes a tty structure. 3087 * 3088 * Locking: none - @tty in question is not exposed at this point 3089 */ 3090 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx) 3091 { 3092 struct tty_struct *tty; 3093 3094 tty = kzalloc(sizeof(*tty), GFP_KERNEL_ACCOUNT); 3095 if (!tty) 3096 return NULL; 3097 3098 kref_init(&tty->kref); 3099 if (tty_ldisc_init(tty)) { 3100 kfree(tty); 3101 return NULL; 3102 } 3103 tty->ctrl.session = NULL; 3104 tty->ctrl.pgrp = NULL; 3105 mutex_init(&tty->legacy_mutex); 3106 mutex_init(&tty->throttle_mutex); 3107 init_rwsem(&tty->termios_rwsem); 3108 mutex_init(&tty->winsize_mutex); 3109 init_ldsem(&tty->ldisc_sem); 3110 init_waitqueue_head(&tty->write_wait); 3111 init_waitqueue_head(&tty->read_wait); 3112 INIT_WORK(&tty->hangup_work, do_tty_hangup); 3113 mutex_init(&tty->atomic_write_lock); 3114 spin_lock_init(&tty->ctrl.lock); 3115 spin_lock_init(&tty->flow.lock); 3116 spin_lock_init(&tty->files_lock); 3117 INIT_LIST_HEAD(&tty->tty_files); 3118 INIT_WORK(&tty->SAK_work, do_SAK_work); 3119 3120 tty->driver = driver; 3121 tty->ops = driver->ops; 3122 tty->index = idx; 3123 tty_line_name(driver, idx, tty->name); 3124 tty->dev = tty_get_device(tty); 3125 3126 return tty; 3127 } 3128 3129 /** 3130 * tty_put_char - write one character to a tty 3131 * @tty: tty 3132 * @ch: character to write 3133 * 3134 * Write one byte to the @tty using the provided @tty->ops->put_char() method 3135 * if present. 3136 * 3137 * Note: the specific put_char operation in the driver layer may go 3138 * away soon. Don't call it directly, use this method 3139 * 3140 * Return: the number of characters successfully output. 3141 */ 3142 int tty_put_char(struct tty_struct *tty, unsigned char ch) 3143 { 3144 if (tty->ops->put_char) 3145 return tty->ops->put_char(tty, ch); 3146 return tty->ops->write(tty, &ch, 1); 3147 } 3148 EXPORT_SYMBOL_GPL(tty_put_char); 3149 3150 static int tty_cdev_add(struct tty_driver *driver, dev_t dev, 3151 unsigned int index, unsigned int count) 3152 { 3153 int err; 3154 3155 /* init here, since reused cdevs cause crashes */ 3156 driver->cdevs[index] = cdev_alloc(); 3157 if (!driver->cdevs[index]) 3158 return -ENOMEM; 3159 driver->cdevs[index]->ops = &tty_fops; 3160 driver->cdevs[index]->owner = driver->owner; 3161 err = cdev_add(driver->cdevs[index], dev, count); 3162 if (err) 3163 kobject_put(&driver->cdevs[index]->kobj); 3164 return err; 3165 } 3166 3167 /** 3168 * tty_register_device - register a tty device 3169 * @driver: the tty driver that describes the tty device 3170 * @index: the index in the tty driver for this tty device 3171 * @device: a struct device that is associated with this tty device. 3172 * This field is optional, if there is no known struct device 3173 * for this tty device it can be set to NULL safely. 3174 * 3175 * This call is required to be made to register an individual tty device 3176 * if the tty driver's flags have the %TTY_DRIVER_DYNAMIC_DEV bit set. If 3177 * that bit is not set, this function should not be called by a tty 3178 * driver. 3179 * 3180 * Locking: ?? 3181 * 3182 * Return: A pointer to the struct device for this tty device (or 3183 * ERR_PTR(-EFOO) on error). 3184 */ 3185 struct device *tty_register_device(struct tty_driver *driver, unsigned index, 3186 struct device *device) 3187 { 3188 return tty_register_device_attr(driver, index, device, NULL, NULL); 3189 } 3190 EXPORT_SYMBOL(tty_register_device); 3191 3192 static void tty_device_create_release(struct device *dev) 3193 { 3194 dev_dbg(dev, "releasing...\n"); 3195 kfree(dev); 3196 } 3197 3198 /** 3199 * tty_register_device_attr - register a tty device 3200 * @driver: the tty driver that describes the tty device 3201 * @index: the index in the tty driver for this tty device 3202 * @device: a struct device that is associated with this tty device. 3203 * This field is optional, if there is no known struct device 3204 * for this tty device it can be set to %NULL safely. 3205 * @drvdata: Driver data to be set to device. 3206 * @attr_grp: Attribute group to be set on device. 3207 * 3208 * This call is required to be made to register an individual tty device if the 3209 * tty driver's flags have the %TTY_DRIVER_DYNAMIC_DEV bit set. If that bit is 3210 * not set, this function should not be called by a tty driver. 3211 * 3212 * Locking: ?? 3213 * 3214 * Return: A pointer to the struct device for this tty device (or 3215 * ERR_PTR(-EFOO) on error). 3216 */ 3217 struct device *tty_register_device_attr(struct tty_driver *driver, 3218 unsigned index, struct device *device, 3219 void *drvdata, 3220 const struct attribute_group **attr_grp) 3221 { 3222 char name[64]; 3223 dev_t devt = MKDEV(driver->major, driver->minor_start) + index; 3224 struct ktermios *tp; 3225 struct device *dev; 3226 int retval; 3227 3228 if (index >= driver->num) { 3229 pr_err("%s: Attempt to register invalid tty line number (%d)\n", 3230 driver->name, index); 3231 return ERR_PTR(-EINVAL); 3232 } 3233 3234 if (driver->type == TTY_DRIVER_TYPE_PTY) 3235 pty_line_name(driver, index, name); 3236 else 3237 tty_line_name(driver, index, name); 3238 3239 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 3240 if (!dev) 3241 return ERR_PTR(-ENOMEM); 3242 3243 dev->devt = devt; 3244 dev->class = &tty_class; 3245 dev->parent = device; 3246 dev->release = tty_device_create_release; 3247 dev_set_name(dev, "%s", name); 3248 dev->groups = attr_grp; 3249 dev_set_drvdata(dev, drvdata); 3250 3251 dev_set_uevent_suppress(dev, 1); 3252 3253 retval = device_register(dev); 3254 if (retval) 3255 goto err_put; 3256 3257 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) { 3258 /* 3259 * Free any saved termios data so that the termios state is 3260 * reset when reusing a minor number. 3261 */ 3262 tp = driver->termios[index]; 3263 if (tp) { 3264 driver->termios[index] = NULL; 3265 kfree(tp); 3266 } 3267 3268 retval = tty_cdev_add(driver, devt, index, 1); 3269 if (retval) 3270 goto err_del; 3271 } 3272 3273 dev_set_uevent_suppress(dev, 0); 3274 kobject_uevent(&dev->kobj, KOBJ_ADD); 3275 3276 return dev; 3277 3278 err_del: 3279 device_del(dev); 3280 err_put: 3281 put_device(dev); 3282 3283 return ERR_PTR(retval); 3284 } 3285 EXPORT_SYMBOL_GPL(tty_register_device_attr); 3286 3287 /** 3288 * tty_unregister_device - unregister a tty device 3289 * @driver: the tty driver that describes the tty device 3290 * @index: the index in the tty driver for this tty device 3291 * 3292 * If a tty device is registered with a call to tty_register_device() then 3293 * this function must be called when the tty device is gone. 3294 * 3295 * Locking: ?? 3296 */ 3297 void tty_unregister_device(struct tty_driver *driver, unsigned index) 3298 { 3299 device_destroy(&tty_class, MKDEV(driver->major, driver->minor_start) + index); 3300 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) { 3301 cdev_del(driver->cdevs[index]); 3302 driver->cdevs[index] = NULL; 3303 } 3304 } 3305 EXPORT_SYMBOL(tty_unregister_device); 3306 3307 /** 3308 * __tty_alloc_driver -- allocate tty driver 3309 * @lines: count of lines this driver can handle at most 3310 * @owner: module which is responsible for this driver 3311 * @flags: some of %TTY_DRIVER_ flags, will be set in driver->flags 3312 * 3313 * This should not be called directly, some of the provided macros should be 3314 * used instead. Use IS_ERR() and friends on @retval. 3315 */ 3316 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner, 3317 unsigned long flags) 3318 { 3319 struct tty_driver *driver; 3320 unsigned int cdevs = 1; 3321 int err; 3322 3323 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1)) 3324 return ERR_PTR(-EINVAL); 3325 3326 driver = kzalloc(sizeof(*driver), GFP_KERNEL); 3327 if (!driver) 3328 return ERR_PTR(-ENOMEM); 3329 3330 kref_init(&driver->kref); 3331 driver->num = lines; 3332 driver->owner = owner; 3333 driver->flags = flags; 3334 3335 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) { 3336 driver->ttys = kcalloc(lines, sizeof(*driver->ttys), 3337 GFP_KERNEL); 3338 driver->termios = kcalloc(lines, sizeof(*driver->termios), 3339 GFP_KERNEL); 3340 if (!driver->ttys || !driver->termios) { 3341 err = -ENOMEM; 3342 goto err_free_all; 3343 } 3344 } 3345 3346 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) { 3347 driver->ports = kcalloc(lines, sizeof(*driver->ports), 3348 GFP_KERNEL); 3349 if (!driver->ports) { 3350 err = -ENOMEM; 3351 goto err_free_all; 3352 } 3353 cdevs = lines; 3354 } 3355 3356 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL); 3357 if (!driver->cdevs) { 3358 err = -ENOMEM; 3359 goto err_free_all; 3360 } 3361 3362 return driver; 3363 err_free_all: 3364 kfree(driver->ports); 3365 kfree(driver->ttys); 3366 kfree(driver->termios); 3367 kfree(driver->cdevs); 3368 kfree(driver); 3369 return ERR_PTR(err); 3370 } 3371 EXPORT_SYMBOL(__tty_alloc_driver); 3372 3373 static void destruct_tty_driver(struct kref *kref) 3374 { 3375 struct tty_driver *driver = container_of(kref, struct tty_driver, kref); 3376 int i; 3377 struct ktermios *tp; 3378 3379 if (driver->flags & TTY_DRIVER_INSTALLED) { 3380 for (i = 0; i < driver->num; i++) { 3381 tp = driver->termios[i]; 3382 if (tp) { 3383 driver->termios[i] = NULL; 3384 kfree(tp); 3385 } 3386 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) 3387 tty_unregister_device(driver, i); 3388 } 3389 proc_tty_unregister_driver(driver); 3390 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) 3391 cdev_del(driver->cdevs[0]); 3392 } 3393 kfree(driver->cdevs); 3394 kfree(driver->ports); 3395 kfree(driver->termios); 3396 kfree(driver->ttys); 3397 kfree(driver); 3398 } 3399 3400 /** 3401 * tty_driver_kref_put -- drop a reference to a tty driver 3402 * @driver: driver of which to drop the reference 3403 * 3404 * The final put will destroy and free up the driver. 3405 */ 3406 void tty_driver_kref_put(struct tty_driver *driver) 3407 { 3408 kref_put(&driver->kref, destruct_tty_driver); 3409 } 3410 EXPORT_SYMBOL(tty_driver_kref_put); 3411 3412 /** 3413 * tty_register_driver -- register a tty driver 3414 * @driver: driver to register 3415 * 3416 * Called by a tty driver to register itself. 3417 */ 3418 int tty_register_driver(struct tty_driver *driver) 3419 { 3420 int error; 3421 int i; 3422 dev_t dev; 3423 struct device *d; 3424 3425 if (!driver->major) { 3426 error = alloc_chrdev_region(&dev, driver->minor_start, 3427 driver->num, driver->name); 3428 if (!error) { 3429 driver->major = MAJOR(dev); 3430 driver->minor_start = MINOR(dev); 3431 } 3432 } else { 3433 dev = MKDEV(driver->major, driver->minor_start); 3434 error = register_chrdev_region(dev, driver->num, driver->name); 3435 } 3436 if (error < 0) 3437 goto err; 3438 3439 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) { 3440 error = tty_cdev_add(driver, dev, 0, driver->num); 3441 if (error) 3442 goto err_unreg_char; 3443 } 3444 3445 mutex_lock(&tty_mutex); 3446 list_add(&driver->tty_drivers, &tty_drivers); 3447 mutex_unlock(&tty_mutex); 3448 3449 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) { 3450 for (i = 0; i < driver->num; i++) { 3451 d = tty_register_device(driver, i, NULL); 3452 if (IS_ERR(d)) { 3453 error = PTR_ERR(d); 3454 goto err_unreg_devs; 3455 } 3456 } 3457 } 3458 proc_tty_register_driver(driver); 3459 driver->flags |= TTY_DRIVER_INSTALLED; 3460 return 0; 3461 3462 err_unreg_devs: 3463 for (i--; i >= 0; i--) 3464 tty_unregister_device(driver, i); 3465 3466 mutex_lock(&tty_mutex); 3467 list_del(&driver->tty_drivers); 3468 mutex_unlock(&tty_mutex); 3469 3470 err_unreg_char: 3471 unregister_chrdev_region(dev, driver->num); 3472 err: 3473 return error; 3474 } 3475 EXPORT_SYMBOL(tty_register_driver); 3476 3477 /** 3478 * tty_unregister_driver -- unregister a tty driver 3479 * @driver: driver to unregister 3480 * 3481 * Called by a tty driver to unregister itself. 3482 */ 3483 void tty_unregister_driver(struct tty_driver *driver) 3484 { 3485 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), 3486 driver->num); 3487 mutex_lock(&tty_mutex); 3488 list_del(&driver->tty_drivers); 3489 mutex_unlock(&tty_mutex); 3490 } 3491 EXPORT_SYMBOL(tty_unregister_driver); 3492 3493 dev_t tty_devnum(struct tty_struct *tty) 3494 { 3495 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; 3496 } 3497 EXPORT_SYMBOL(tty_devnum); 3498 3499 void tty_default_fops(struct file_operations *fops) 3500 { 3501 *fops = tty_fops; 3502 } 3503 3504 static char *tty_devnode(const struct device *dev, umode_t *mode) 3505 { 3506 if (!mode) 3507 return NULL; 3508 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) || 3509 dev->devt == MKDEV(TTYAUX_MAJOR, 2)) 3510 *mode = 0666; 3511 return NULL; 3512 } 3513 3514 const struct class tty_class = { 3515 .name = "tty", 3516 .devnode = tty_devnode, 3517 }; 3518 3519 static int __init tty_class_init(void) 3520 { 3521 return class_register(&tty_class); 3522 } 3523 3524 postcore_initcall(tty_class_init); 3525 3526 /* 3/2004 jmc: why do these devices exist? */ 3527 static struct cdev tty_cdev, console_cdev; 3528 3529 static ssize_t show_cons_active(struct device *dev, 3530 struct device_attribute *attr, char *buf) 3531 { 3532 struct console *cs[16]; 3533 int i = 0; 3534 struct console *c; 3535 ssize_t count = 0; 3536 3537 /* 3538 * Hold the console_list_lock to guarantee that no consoles are 3539 * unregistered until all console processing is complete. 3540 * This also allows safe traversal of the console list and 3541 * race-free reading of @flags. 3542 */ 3543 console_list_lock(); 3544 3545 for_each_console(c) { 3546 if (!c->device) 3547 continue; 3548 if (!c->write) 3549 continue; 3550 if ((c->flags & CON_ENABLED) == 0) 3551 continue; 3552 cs[i++] = c; 3553 if (i >= ARRAY_SIZE(cs)) 3554 break; 3555 } 3556 3557 /* 3558 * Take console_lock to serialize device() callback with 3559 * other console operations. For example, fg_console is 3560 * modified under console_lock when switching vt. 3561 */ 3562 console_lock(); 3563 while (i--) { 3564 int index = cs[i]->index; 3565 struct tty_driver *drv = cs[i]->device(cs[i], &index); 3566 3567 /* don't resolve tty0 as some programs depend on it */ 3568 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR)) 3569 count += tty_line_name(drv, index, buf + count); 3570 else 3571 count += sprintf(buf + count, "%s%d", 3572 cs[i]->name, cs[i]->index); 3573 3574 count += sprintf(buf + count, "%c", i ? ' ':'\n'); 3575 } 3576 console_unlock(); 3577 3578 console_list_unlock(); 3579 3580 return count; 3581 } 3582 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL); 3583 3584 static struct attribute *cons_dev_attrs[] = { 3585 &dev_attr_active.attr, 3586 NULL 3587 }; 3588 3589 ATTRIBUTE_GROUPS(cons_dev); 3590 3591 static struct device *consdev; 3592 3593 void console_sysfs_notify(void) 3594 { 3595 if (consdev) 3596 sysfs_notify(&consdev->kobj, NULL, "active"); 3597 } 3598 3599 static struct ctl_table tty_table[] = { 3600 { 3601 .procname = "legacy_tiocsti", 3602 .data = &tty_legacy_tiocsti, 3603 .maxlen = sizeof(tty_legacy_tiocsti), 3604 .mode = 0644, 3605 .proc_handler = proc_dobool, 3606 }, 3607 { 3608 .procname = "ldisc_autoload", 3609 .data = &tty_ldisc_autoload, 3610 .maxlen = sizeof(tty_ldisc_autoload), 3611 .mode = 0644, 3612 .proc_handler = proc_dointvec, 3613 .extra1 = SYSCTL_ZERO, 3614 .extra2 = SYSCTL_ONE, 3615 }, 3616 { } 3617 }; 3618 3619 /* 3620 * Ok, now we can initialize the rest of the tty devices and can count 3621 * on memory allocations, interrupts etc.. 3622 */ 3623 int __init tty_init(void) 3624 { 3625 register_sysctl_init("dev/tty", tty_table); 3626 cdev_init(&tty_cdev, &tty_fops); 3627 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || 3628 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) 3629 panic("Couldn't register /dev/tty driver\n"); 3630 device_create(&tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty"); 3631 3632 cdev_init(&console_cdev, &console_fops); 3633 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || 3634 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) 3635 panic("Couldn't register /dev/console driver\n"); 3636 consdev = device_create_with_groups(&tty_class, NULL, 3637 MKDEV(TTYAUX_MAJOR, 1), NULL, 3638 cons_dev_groups, "console"); 3639 if (IS_ERR(consdev)) 3640 consdev = NULL; 3641 3642 #ifdef CONFIG_VT 3643 vty_init(&console_fops); 3644 #endif 3645 return 0; 3646 } 3647