| 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 | } |