| 1 | /* |
| 2 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 3 | * |
| 4 | * Added support for a Unix98-style ptmx device. |
| 5 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 |
| 6 | * |
| 7 | */ |
| 8 | |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/errno.h> |
| 11 | #include <linux/interrupt.h> |
| 12 | #include <linux/tty.h> |
| 13 | #include <linux/tty_flip.h> |
| 14 | #include <linux/fcntl.h> |
| 15 | #include <linux/sched.h> |
| 16 | #include <linux/string.h> |
| 17 | #include <linux/major.h> |
| 18 | #include <linux/mm.h> |
| 19 | #include <linux/init.h> |
| 20 | #include <linux/device.h> |
| 21 | #include <linux/uaccess.h> |
| 22 | #include <linux/bitops.h> |
| 23 | #include <linux/devpts_fs.h> |
| 24 | #include <linux/slab.h> |
| 25 | #include <linux/mutex.h> |
| 26 | #include <linux/poll.h> |
| 27 | |
| 28 | #undef TTY_DEBUG_HANGUP |
| 29 | #ifdef TTY_DEBUG_HANGUP |
| 30 | # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args) |
| 31 | #else |
| 32 | # define tty_debug_hangup(tty, f, args...) do {} while (0) |
| 33 | #endif |
| 34 | |
| 35 | #ifdef CONFIG_UNIX98_PTYS |
| 36 | static struct tty_driver *ptm_driver; |
| 37 | static struct tty_driver *pts_driver; |
| 38 | static DEFINE_MUTEX(devpts_mutex); |
| 39 | #endif |
| 40 | |
| 41 | static void pty_close(struct tty_struct *tty, struct file *filp) |
| 42 | { |
| 43 | BUG_ON(!tty); |
| 44 | if (tty->driver->subtype == PTY_TYPE_MASTER) |
| 45 | WARN_ON(tty->count > 1); |
| 46 | else { |
| 47 | if (test_bit(TTY_IO_ERROR, &tty->flags)) |
| 48 | return; |
| 49 | if (tty->count > 2) |
| 50 | return; |
| 51 | } |
| 52 | set_bit(TTY_IO_ERROR, &tty->flags); |
| 53 | wake_up_interruptible(&tty->read_wait); |
| 54 | wake_up_interruptible(&tty->write_wait); |
| 55 | spin_lock_irq(&tty->ctrl_lock); |
| 56 | tty->packet = 0; |
| 57 | spin_unlock_irq(&tty->ctrl_lock); |
| 58 | /* Review - krefs on tty_link ?? */ |
| 59 | if (!tty->link) |
| 60 | return; |
| 61 | set_bit(TTY_OTHER_CLOSED, &tty->link->flags); |
| 62 | tty_flip_buffer_push(tty->link->port); |
| 63 | wake_up_interruptible(&tty->link->write_wait); |
| 64 | if (tty->driver->subtype == PTY_TYPE_MASTER) { |
| 65 | set_bit(TTY_OTHER_CLOSED, &tty->flags); |
| 66 | #ifdef CONFIG_UNIX98_PTYS |
| 67 | if (tty->driver == ptm_driver) { |
| 68 | mutex_lock(&devpts_mutex); |
| 69 | if (tty->link->driver_data) |
| 70 | devpts_pty_kill(tty->link->driver_data); |
| 71 | mutex_unlock(&devpts_mutex); |
| 72 | } |
| 73 | #endif |
| 74 | tty_vhangup(tty->link); |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | /* |
| 79 | * The unthrottle routine is called by the line discipline to signal |
| 80 | * that it can receive more characters. For PTY's, the TTY_THROTTLED |
| 81 | * flag is always set, to force the line discipline to always call the |
| 82 | * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE |
| 83 | * characters in the queue. This is necessary since each time this |
| 84 | * happens, we need to wake up any sleeping processes that could be |
| 85 | * (1) trying to send data to the pty, or (2) waiting in wait_until_sent() |
| 86 | * for the pty buffer to be drained. |
| 87 | */ |
| 88 | static void pty_unthrottle(struct tty_struct *tty) |
| 89 | { |
| 90 | tty_wakeup(tty->link); |
| 91 | set_bit(TTY_THROTTLED, &tty->flags); |
| 92 | } |
| 93 | |
| 94 | /** |
| 95 | * pty_write - write to a pty |
| 96 | * @tty: the tty we write from |
| 97 | * @buf: kernel buffer of data |
| 98 | * @count: bytes to write |
| 99 | * |
| 100 | * Our "hardware" write method. Data is coming from the ldisc which |
| 101 | * may be in a non sleeping state. We simply throw this at the other |
| 102 | * end of the link as if we were an IRQ handler receiving stuff for |
| 103 | * the other side of the pty/tty pair. |
| 104 | */ |
| 105 | |
| 106 | static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c) |
| 107 | { |
| 108 | struct tty_struct *to = tty->link; |
| 109 | |
| 110 | if (tty->stopped) |
| 111 | return 0; |
| 112 | |
| 113 | if (c > 0) { |
| 114 | /* Stuff the data into the input queue of the other end */ |
| 115 | c = tty_insert_flip_string(to->port, buf, c); |
| 116 | /* And shovel */ |
| 117 | if (c) |
| 118 | tty_flip_buffer_push(to->port); |
| 119 | } |
| 120 | return c; |
| 121 | } |
| 122 | |
| 123 | /** |
| 124 | * pty_write_room - write space |
| 125 | * @tty: tty we are writing from |
| 126 | * |
| 127 | * Report how many bytes the ldisc can send into the queue for |
| 128 | * the other device. |
| 129 | */ |
| 130 | |
| 131 | static int pty_write_room(struct tty_struct *tty) |
| 132 | { |
| 133 | if (tty->stopped) |
| 134 | return 0; |
| 135 | return tty_buffer_space_avail(tty->link->port); |
| 136 | } |
| 137 | |
| 138 | /** |
| 139 | * pty_chars_in_buffer - characters currently in our tx queue |
| 140 | * @tty: our tty |
| 141 | * |
| 142 | * Report how much we have in the transmit queue. As everything is |
| 143 | * instantly at the other end this is easy to implement. |
| 144 | */ |
| 145 | |
| 146 | static int pty_chars_in_buffer(struct tty_struct *tty) |
| 147 | { |
| 148 | return 0; |
| 149 | } |
| 150 | |
| 151 | /* Set the lock flag on a pty */ |
| 152 | static int pty_set_lock(struct tty_struct *tty, int __user *arg) |
| 153 | { |
| 154 | int val; |
| 155 | if (get_user(val, arg)) |
| 156 | return -EFAULT; |
| 157 | if (val) |
| 158 | set_bit(TTY_PTY_LOCK, &tty->flags); |
| 159 | else |
| 160 | clear_bit(TTY_PTY_LOCK, &tty->flags); |
| 161 | return 0; |
| 162 | } |
| 163 | |
| 164 | static int pty_get_lock(struct tty_struct *tty, int __user *arg) |
| 165 | { |
| 166 | int locked = test_bit(TTY_PTY_LOCK, &tty->flags); |
| 167 | return put_user(locked, arg); |
| 168 | } |
| 169 | |
| 170 | /* Set the packet mode on a pty */ |
| 171 | static int pty_set_pktmode(struct tty_struct *tty, int __user *arg) |
| 172 | { |
| 173 | int pktmode; |
| 174 | |
| 175 | if (get_user(pktmode, arg)) |
| 176 | return -EFAULT; |
| 177 | |
| 178 | spin_lock_irq(&tty->ctrl_lock); |
| 179 | if (pktmode) { |
| 180 | if (!tty->packet) { |
| 181 | tty->link->ctrl_status = 0; |
| 182 | smp_mb(); |
| 183 | tty->packet = 1; |
| 184 | } |
| 185 | } else |
| 186 | tty->packet = 0; |
| 187 | spin_unlock_irq(&tty->ctrl_lock); |
| 188 | |
| 189 | return 0; |
| 190 | } |
| 191 | |
| 192 | /* Get the packet mode of a pty */ |
| 193 | static int pty_get_pktmode(struct tty_struct *tty, int __user *arg) |
| 194 | { |
| 195 | int pktmode = tty->packet; |
| 196 | return put_user(pktmode, arg); |
| 197 | } |
| 198 | |
| 199 | /* Send a signal to the slave */ |
| 200 | static int pty_signal(struct tty_struct *tty, int sig) |
| 201 | { |
| 202 | struct pid *pgrp; |
| 203 | |
| 204 | if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP) |
| 205 | return -EINVAL; |
| 206 | |
| 207 | if (tty->link) { |
| 208 | pgrp = tty_get_pgrp(tty->link); |
| 209 | if (pgrp) |
| 210 | kill_pgrp(pgrp, sig, 1); |
| 211 | put_pid(pgrp); |
| 212 | } |
| 213 | return 0; |
| 214 | } |
| 215 | |
| 216 | static void pty_flush_buffer(struct tty_struct *tty) |
| 217 | { |
| 218 | struct tty_struct *to = tty->link; |
| 219 | struct tty_ldisc *ld; |
| 220 | |
| 221 | if (!to) |
| 222 | return; |
| 223 | |
| 224 | ld = tty_ldisc_ref(to); |
| 225 | tty_buffer_flush(to, ld); |
| 226 | if (ld) |
| 227 | tty_ldisc_deref(ld); |
| 228 | |
| 229 | if (to->packet) { |
| 230 | spin_lock_irq(&tty->ctrl_lock); |
| 231 | tty->ctrl_status |= TIOCPKT_FLUSHWRITE; |
| 232 | wake_up_interruptible(&to->read_wait); |
| 233 | spin_unlock_irq(&tty->ctrl_lock); |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | static int pty_open(struct tty_struct *tty, struct file *filp) |
| 238 | { |
| 239 | if (!tty || !tty->link) |
| 240 | return -ENODEV; |
| 241 | |
| 242 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
| 243 | goto out; |
| 244 | if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) |
| 245 | goto out; |
| 246 | if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1) |
| 247 | goto out; |
| 248 | |
| 249 | clear_bit(TTY_IO_ERROR, &tty->flags); |
| 250 | /* TTY_OTHER_CLOSED must be cleared before TTY_OTHER_DONE */ |
| 251 | clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); |
| 252 | clear_bit(TTY_OTHER_DONE, &tty->link->flags); |
| 253 | set_bit(TTY_THROTTLED, &tty->flags); |
| 254 | return 0; |
| 255 | |
| 256 | out: |
| 257 | set_bit(TTY_IO_ERROR, &tty->flags); |
| 258 | return -EIO; |
| 259 | } |
| 260 | |
| 261 | static void pty_set_termios(struct tty_struct *tty, |
| 262 | struct ktermios *old_termios) |
| 263 | { |
| 264 | /* See if packet mode change of state. */ |
| 265 | if (tty->link && tty->link->packet) { |
| 266 | int extproc = (old_termios->c_lflag & EXTPROC) | L_EXTPROC(tty); |
| 267 | int old_flow = ((old_termios->c_iflag & IXON) && |
| 268 | (old_termios->c_cc[VSTOP] == '\023') && |
| 269 | (old_termios->c_cc[VSTART] == '\021')); |
| 270 | int new_flow = (I_IXON(tty) && |
| 271 | STOP_CHAR(tty) == '\023' && |
| 272 | START_CHAR(tty) == '\021'); |
| 273 | if ((old_flow != new_flow) || extproc) { |
| 274 | spin_lock_irq(&tty->ctrl_lock); |
| 275 | if (old_flow != new_flow) { |
| 276 | tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP); |
| 277 | if (new_flow) |
| 278 | tty->ctrl_status |= TIOCPKT_DOSTOP; |
| 279 | else |
| 280 | tty->ctrl_status |= TIOCPKT_NOSTOP; |
| 281 | } |
| 282 | if (extproc) |
| 283 | tty->ctrl_status |= TIOCPKT_IOCTL; |
| 284 | spin_unlock_irq(&tty->ctrl_lock); |
| 285 | wake_up_interruptible(&tty->link->read_wait); |
| 286 | } |
| 287 | } |
| 288 | |
| 289 | tty->termios.c_cflag &= ~(CSIZE | PARENB); |
| 290 | tty->termios.c_cflag |= (CS8 | CREAD); |
| 291 | } |
| 292 | |
| 293 | /** |
| 294 | * pty_do_resize - resize event |
| 295 | * @tty: tty being resized |
| 296 | * @ws: window size being set. |
| 297 | * |
| 298 | * Update the termios variables and send the necessary signals to |
| 299 | * peform a terminal resize correctly |
| 300 | */ |
| 301 | |
| 302 | static int pty_resize(struct tty_struct *tty, struct winsize *ws) |
| 303 | { |
| 304 | struct pid *pgrp, *rpgrp; |
| 305 | struct tty_struct *pty = tty->link; |
| 306 | |
| 307 | /* For a PTY we need to lock the tty side */ |
| 308 | mutex_lock(&tty->winsize_mutex); |
| 309 | if (!memcmp(ws, &tty->winsize, sizeof(*ws))) |
| 310 | goto done; |
| 311 | |
| 312 | /* Signal the foreground process group of both ptys */ |
| 313 | pgrp = tty_get_pgrp(tty); |
| 314 | rpgrp = tty_get_pgrp(pty); |
| 315 | |
| 316 | if (pgrp) |
| 317 | kill_pgrp(pgrp, SIGWINCH, 1); |
| 318 | if (rpgrp != pgrp && rpgrp) |
| 319 | kill_pgrp(rpgrp, SIGWINCH, 1); |
| 320 | |
| 321 | put_pid(pgrp); |
| 322 | put_pid(rpgrp); |
| 323 | |
| 324 | tty->winsize = *ws; |
| 325 | pty->winsize = *ws; /* Never used so will go away soon */ |
| 326 | done: |
| 327 | mutex_unlock(&tty->winsize_mutex); |
| 328 | return 0; |
| 329 | } |
| 330 | |
| 331 | /** |
| 332 | * pty_start - start() handler |
| 333 | * pty_stop - stop() handler |
| 334 | * @tty: tty being flow-controlled |
| 335 | * |
| 336 | * Propagates the TIOCPKT status to the master pty. |
| 337 | * |
| 338 | * NB: only the master pty can be in packet mode so only the slave |
| 339 | * needs start()/stop() handlers |
| 340 | */ |
| 341 | static void pty_start(struct tty_struct *tty) |
| 342 | { |
| 343 | unsigned long flags; |
| 344 | |
| 345 | if (tty->link && tty->link->packet) { |
| 346 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
| 347 | tty->ctrl_status &= ~TIOCPKT_STOP; |
| 348 | tty->ctrl_status |= TIOCPKT_START; |
| 349 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
| 350 | wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); |
| 351 | } |
| 352 | } |
| 353 | |
| 354 | static void pty_stop(struct tty_struct *tty) |
| 355 | { |
| 356 | unsigned long flags; |
| 357 | |
| 358 | if (tty->link && tty->link->packet) { |
| 359 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
| 360 | tty->ctrl_status &= ~TIOCPKT_START; |
| 361 | tty->ctrl_status |= TIOCPKT_STOP; |
| 362 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
| 363 | wake_up_interruptible_poll(&tty->link->read_wait, POLLIN); |
| 364 | } |
| 365 | } |
| 366 | |
| 367 | /** |
| 368 | * pty_common_install - set up the pty pair |
| 369 | * @driver: the pty driver |
| 370 | * @tty: the tty being instantiated |
| 371 | * @legacy: true if this is BSD style |
| 372 | * |
| 373 | * Perform the initial set up for the tty/pty pair. Called from the |
| 374 | * tty layer when the port is first opened. |
| 375 | * |
| 376 | * Locking: the caller must hold the tty_mutex |
| 377 | */ |
| 378 | static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, |
| 379 | bool legacy) |
| 380 | { |
| 381 | struct tty_struct *o_tty; |
| 382 | struct tty_port *ports[2]; |
| 383 | int idx = tty->index; |
| 384 | int retval = -ENOMEM; |
| 385 | |
| 386 | /* Opening the slave first has always returned -EIO */ |
| 387 | if (driver->subtype != PTY_TYPE_MASTER) |
| 388 | return -EIO; |
| 389 | |
| 390 | ports[0] = kmalloc(sizeof **ports, GFP_KERNEL); |
| 391 | ports[1] = kmalloc(sizeof **ports, GFP_KERNEL); |
| 392 | if (!ports[0] || !ports[1]) |
| 393 | goto err; |
| 394 | if (!try_module_get(driver->other->owner)) { |
| 395 | /* This cannot in fact currently happen */ |
| 396 | goto err; |
| 397 | } |
| 398 | o_tty = alloc_tty_struct(driver->other, idx); |
| 399 | if (!o_tty) |
| 400 | goto err_put_module; |
| 401 | |
| 402 | tty_set_lock_subclass(o_tty); |
| 403 | lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE); |
| 404 | |
| 405 | if (legacy) { |
| 406 | /* We always use new tty termios data so we can do this |
| 407 | the easy way .. */ |
| 408 | tty_init_termios(tty); |
| 409 | tty_init_termios(o_tty); |
| 410 | |
| 411 | driver->other->ttys[idx] = o_tty; |
| 412 | driver->ttys[idx] = tty; |
| 413 | } else { |
| 414 | memset(&tty->termios_locked, 0, sizeof(tty->termios_locked)); |
| 415 | tty->termios = driver->init_termios; |
| 416 | memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked)); |
| 417 | o_tty->termios = driver->other->init_termios; |
| 418 | } |
| 419 | |
| 420 | /* |
| 421 | * Everything allocated ... set up the o_tty structure. |
| 422 | */ |
| 423 | tty_driver_kref_get(driver->other); |
| 424 | /* Establish the links in both directions */ |
| 425 | tty->link = o_tty; |
| 426 | o_tty->link = tty; |
| 427 | tty_port_init(ports[0]); |
| 428 | tty_port_init(ports[1]); |
| 429 | tty_buffer_set_limit(ports[0], 8192); |
| 430 | tty_buffer_set_limit(ports[1], 8192); |
| 431 | o_tty->port = ports[0]; |
| 432 | tty->port = ports[1]; |
| 433 | o_tty->port->itty = o_tty; |
| 434 | |
| 435 | tty_buffer_set_lock_subclass(o_tty->port); |
| 436 | |
| 437 | tty_driver_kref_get(driver); |
| 438 | tty->count++; |
| 439 | o_tty->count++; |
| 440 | return 0; |
| 441 | |
| 442 | err_put_module: |
| 443 | module_put(driver->other->owner); |
| 444 | err: |
| 445 | kfree(ports[0]); |
| 446 | kfree(ports[1]); |
| 447 | return retval; |
| 448 | } |
| 449 | |
| 450 | static void pty_cleanup(struct tty_struct *tty) |
| 451 | { |
| 452 | tty_port_put(tty->port); |
| 453 | } |
| 454 | |
| 455 | /* Traditional BSD devices */ |
| 456 | #ifdef CONFIG_LEGACY_PTYS |
| 457 | |
| 458 | static int pty_install(struct tty_driver *driver, struct tty_struct *tty) |
| 459 | { |
| 460 | return pty_common_install(driver, tty, true); |
| 461 | } |
| 462 | |
| 463 | static void pty_remove(struct tty_driver *driver, struct tty_struct *tty) |
| 464 | { |
| 465 | struct tty_struct *pair = tty->link; |
| 466 | driver->ttys[tty->index] = NULL; |
| 467 | if (pair) |
| 468 | pair->driver->ttys[pair->index] = NULL; |
| 469 | } |
| 470 | |
| 471 | static int pty_bsd_ioctl(struct tty_struct *tty, |
| 472 | unsigned int cmd, unsigned long arg) |
| 473 | { |
| 474 | switch (cmd) { |
| 475 | case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ |
| 476 | return pty_set_lock(tty, (int __user *) arg); |
| 477 | case TIOCGPTLCK: /* Get PT Lock status */ |
| 478 | return pty_get_lock(tty, (int __user *)arg); |
| 479 | case TIOCPKT: /* Set PT packet mode */ |
| 480 | return pty_set_pktmode(tty, (int __user *)arg); |
| 481 | case TIOCGPKT: /* Get PT packet mode */ |
| 482 | return pty_get_pktmode(tty, (int __user *)arg); |
| 483 | case TIOCSIG: /* Send signal to other side of pty */ |
| 484 | return pty_signal(tty, (int) arg); |
| 485 | case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */ |
| 486 | return -EINVAL; |
| 487 | } |
| 488 | return -ENOIOCTLCMD; |
| 489 | } |
| 490 | |
| 491 | static int legacy_count = CONFIG_LEGACY_PTY_COUNT; |
| 492 | /* |
| 493 | * not really modular, but the easiest way to keep compat with existing |
| 494 | * bootargs behaviour is to continue using module_param here. |
| 495 | */ |
| 496 | module_param(legacy_count, int, 0); |
| 497 | |
| 498 | /* |
| 499 | * The master side of a pty can do TIOCSPTLCK and thus |
| 500 | * has pty_bsd_ioctl. |
| 501 | */ |
| 502 | static const struct tty_operations master_pty_ops_bsd = { |
| 503 | .install = pty_install, |
| 504 | .open = pty_open, |
| 505 | .close = pty_close, |
| 506 | .write = pty_write, |
| 507 | .write_room = pty_write_room, |
| 508 | .flush_buffer = pty_flush_buffer, |
| 509 | .chars_in_buffer = pty_chars_in_buffer, |
| 510 | .unthrottle = pty_unthrottle, |
| 511 | .ioctl = pty_bsd_ioctl, |
| 512 | .cleanup = pty_cleanup, |
| 513 | .resize = pty_resize, |
| 514 | .remove = pty_remove |
| 515 | }; |
| 516 | |
| 517 | static const struct tty_operations slave_pty_ops_bsd = { |
| 518 | .install = pty_install, |
| 519 | .open = pty_open, |
| 520 | .close = pty_close, |
| 521 | .write = pty_write, |
| 522 | .write_room = pty_write_room, |
| 523 | .flush_buffer = pty_flush_buffer, |
| 524 | .chars_in_buffer = pty_chars_in_buffer, |
| 525 | .unthrottle = pty_unthrottle, |
| 526 | .set_termios = pty_set_termios, |
| 527 | .cleanup = pty_cleanup, |
| 528 | .resize = pty_resize, |
| 529 | .start = pty_start, |
| 530 | .stop = pty_stop, |
| 531 | .remove = pty_remove |
| 532 | }; |
| 533 | |
| 534 | static void __init legacy_pty_init(void) |
| 535 | { |
| 536 | struct tty_driver *pty_driver, *pty_slave_driver; |
| 537 | |
| 538 | if (legacy_count <= 0) |
| 539 | return; |
| 540 | |
| 541 | pty_driver = tty_alloc_driver(legacy_count, |
| 542 | TTY_DRIVER_RESET_TERMIOS | |
| 543 | TTY_DRIVER_REAL_RAW | |
| 544 | TTY_DRIVER_DYNAMIC_ALLOC); |
| 545 | if (IS_ERR(pty_driver)) |
| 546 | panic("Couldn't allocate pty driver"); |
| 547 | |
| 548 | pty_slave_driver = tty_alloc_driver(legacy_count, |
| 549 | TTY_DRIVER_RESET_TERMIOS | |
| 550 | TTY_DRIVER_REAL_RAW | |
| 551 | TTY_DRIVER_DYNAMIC_ALLOC); |
| 552 | if (IS_ERR(pty_slave_driver)) |
| 553 | panic("Couldn't allocate pty slave driver"); |
| 554 | |
| 555 | pty_driver->driver_name = "pty_master"; |
| 556 | pty_driver->name = "pty"; |
| 557 | pty_driver->major = PTY_MASTER_MAJOR; |
| 558 | pty_driver->minor_start = 0; |
| 559 | pty_driver->type = TTY_DRIVER_TYPE_PTY; |
| 560 | pty_driver->subtype = PTY_TYPE_MASTER; |
| 561 | pty_driver->init_termios = tty_std_termios; |
| 562 | pty_driver->init_termios.c_iflag = 0; |
| 563 | pty_driver->init_termios.c_oflag = 0; |
| 564 | pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
| 565 | pty_driver->init_termios.c_lflag = 0; |
| 566 | pty_driver->init_termios.c_ispeed = 38400; |
| 567 | pty_driver->init_termios.c_ospeed = 38400; |
| 568 | pty_driver->other = pty_slave_driver; |
| 569 | tty_set_operations(pty_driver, &master_pty_ops_bsd); |
| 570 | |
| 571 | pty_slave_driver->driver_name = "pty_slave"; |
| 572 | pty_slave_driver->name = "ttyp"; |
| 573 | pty_slave_driver->major = PTY_SLAVE_MAJOR; |
| 574 | pty_slave_driver->minor_start = 0; |
| 575 | pty_slave_driver->type = TTY_DRIVER_TYPE_PTY; |
| 576 | pty_slave_driver->subtype = PTY_TYPE_SLAVE; |
| 577 | pty_slave_driver->init_termios = tty_std_termios; |
| 578 | pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
| 579 | pty_slave_driver->init_termios.c_ispeed = 38400; |
| 580 | pty_slave_driver->init_termios.c_ospeed = 38400; |
| 581 | pty_slave_driver->other = pty_driver; |
| 582 | tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd); |
| 583 | |
| 584 | if (tty_register_driver(pty_driver)) |
| 585 | panic("Couldn't register pty driver"); |
| 586 | if (tty_register_driver(pty_slave_driver)) |
| 587 | panic("Couldn't register pty slave driver"); |
| 588 | } |
| 589 | #else |
| 590 | static inline void legacy_pty_init(void) { } |
| 591 | #endif |
| 592 | |
| 593 | /* Unix98 devices */ |
| 594 | #ifdef CONFIG_UNIX98_PTYS |
| 595 | |
| 596 | static struct cdev ptmx_cdev; |
| 597 | |
| 598 | static int pty_unix98_ioctl(struct tty_struct *tty, |
| 599 | unsigned int cmd, unsigned long arg) |
| 600 | { |
| 601 | switch (cmd) { |
| 602 | case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ |
| 603 | return pty_set_lock(tty, (int __user *)arg); |
| 604 | case TIOCGPTLCK: /* Get PT Lock status */ |
| 605 | return pty_get_lock(tty, (int __user *)arg); |
| 606 | case TIOCPKT: /* Set PT packet mode */ |
| 607 | return pty_set_pktmode(tty, (int __user *)arg); |
| 608 | case TIOCGPKT: /* Get PT packet mode */ |
| 609 | return pty_get_pktmode(tty, (int __user *)arg); |
| 610 | case TIOCGPTN: /* Get PT Number */ |
| 611 | return put_user(tty->index, (unsigned int __user *)arg); |
| 612 | case TIOCSIG: /* Send signal to other side of pty */ |
| 613 | return pty_signal(tty, (int) arg); |
| 614 | } |
| 615 | |
| 616 | return -ENOIOCTLCMD; |
| 617 | } |
| 618 | |
| 619 | /** |
| 620 | * ptm_unix98_lookup - find a pty master |
| 621 | * @driver: ptm driver |
| 622 | * @idx: tty index |
| 623 | * |
| 624 | * Look up a pty master device. Called under the tty_mutex for now. |
| 625 | * This provides our locking. |
| 626 | */ |
| 627 | |
| 628 | static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, |
| 629 | struct file *file, int idx) |
| 630 | { |
| 631 | /* Master must be open via /dev/ptmx */ |
| 632 | return ERR_PTR(-EIO); |
| 633 | } |
| 634 | |
| 635 | /** |
| 636 | * pts_unix98_lookup - find a pty slave |
| 637 | * @driver: pts driver |
| 638 | * @idx: tty index |
| 639 | * |
| 640 | * Look up a pty master device. Called under the tty_mutex for now. |
| 641 | * This provides our locking for the tty pointer. |
| 642 | */ |
| 643 | |
| 644 | static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, |
| 645 | struct file *file, int idx) |
| 646 | { |
| 647 | struct tty_struct *tty; |
| 648 | |
| 649 | mutex_lock(&devpts_mutex); |
| 650 | tty = devpts_get_priv(file->f_path.dentry); |
| 651 | mutex_unlock(&devpts_mutex); |
| 652 | /* Master must be open before slave */ |
| 653 | if (!tty) |
| 654 | return ERR_PTR(-EIO); |
| 655 | return tty; |
| 656 | } |
| 657 | |
| 658 | static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) |
| 659 | { |
| 660 | return pty_common_install(driver, tty, false); |
| 661 | } |
| 662 | |
| 663 | /* this is called once with whichever end is closed last */ |
| 664 | static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) |
| 665 | { |
| 666 | struct pts_fs_info *fsi; |
| 667 | |
| 668 | if (tty->driver->subtype == PTY_TYPE_MASTER) |
| 669 | fsi = tty->driver_data; |
| 670 | else |
| 671 | fsi = tty->link->driver_data; |
| 672 | devpts_kill_index(fsi, tty->index); |
| 673 | devpts_put_ref(fsi); |
| 674 | } |
| 675 | |
| 676 | static const struct tty_operations ptm_unix98_ops = { |
| 677 | .lookup = ptm_unix98_lookup, |
| 678 | .install = pty_unix98_install, |
| 679 | .remove = pty_unix98_remove, |
| 680 | .open = pty_open, |
| 681 | .close = pty_close, |
| 682 | .write = pty_write, |
| 683 | .write_room = pty_write_room, |
| 684 | .flush_buffer = pty_flush_buffer, |
| 685 | .chars_in_buffer = pty_chars_in_buffer, |
| 686 | .unthrottle = pty_unthrottle, |
| 687 | .ioctl = pty_unix98_ioctl, |
| 688 | .resize = pty_resize, |
| 689 | .cleanup = pty_cleanup |
| 690 | }; |
| 691 | |
| 692 | static const struct tty_operations pty_unix98_ops = { |
| 693 | .lookup = pts_unix98_lookup, |
| 694 | .install = pty_unix98_install, |
| 695 | .remove = pty_unix98_remove, |
| 696 | .open = pty_open, |
| 697 | .close = pty_close, |
| 698 | .write = pty_write, |
| 699 | .write_room = pty_write_room, |
| 700 | .flush_buffer = pty_flush_buffer, |
| 701 | .chars_in_buffer = pty_chars_in_buffer, |
| 702 | .unthrottle = pty_unthrottle, |
| 703 | .set_termios = pty_set_termios, |
| 704 | .start = pty_start, |
| 705 | .stop = pty_stop, |
| 706 | .cleanup = pty_cleanup, |
| 707 | }; |
| 708 | |
| 709 | /** |
| 710 | * ptmx_open - open a unix 98 pty master |
| 711 | * @inode: inode of device file |
| 712 | * @filp: file pointer to tty |
| 713 | * |
| 714 | * Allocate a unix98 pty master device from the ptmx driver. |
| 715 | * |
| 716 | * Locking: tty_mutex protects the init_dev work. tty->count should |
| 717 | * protect the rest. |
| 718 | * allocated_ptys_lock handles the list of free pty numbers |
| 719 | */ |
| 720 | |
| 721 | static int ptmx_open(struct inode *inode, struct file *filp) |
| 722 | { |
| 723 | struct pts_fs_info *fsi; |
| 724 | struct tty_struct *tty; |
| 725 | struct dentry *dentry; |
| 726 | int retval; |
| 727 | int index; |
| 728 | |
| 729 | nonseekable_open(inode, filp); |
| 730 | |
| 731 | /* We refuse fsnotify events on ptmx, since it's a shared resource */ |
| 732 | filp->f_mode |= FMODE_NONOTIFY; |
| 733 | |
| 734 | retval = tty_alloc_file(filp); |
| 735 | if (retval) |
| 736 | return retval; |
| 737 | |
| 738 | fsi = devpts_get_ref(inode, filp); |
| 739 | retval = -ENODEV; |
| 740 | if (!fsi) |
| 741 | goto out_free_file; |
| 742 | |
| 743 | /* find a device that is not in use. */ |
| 744 | mutex_lock(&devpts_mutex); |
| 745 | index = devpts_new_index(fsi); |
| 746 | mutex_unlock(&devpts_mutex); |
| 747 | |
| 748 | retval = index; |
| 749 | if (index < 0) |
| 750 | goto out_put_ref; |
| 751 | |
| 752 | |
| 753 | mutex_lock(&tty_mutex); |
| 754 | tty = tty_init_dev(ptm_driver, index); |
| 755 | /* The tty returned here is locked so we can safely |
| 756 | drop the mutex */ |
| 757 | mutex_unlock(&tty_mutex); |
| 758 | |
| 759 | retval = PTR_ERR(tty); |
| 760 | if (IS_ERR(tty)) |
| 761 | goto out; |
| 762 | |
| 763 | /* |
| 764 | * From here on out, the tty is "live", and the index and |
| 765 | * fsi will be killed/put by the tty_release() |
| 766 | */ |
| 767 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ |
| 768 | tty->driver_data = fsi; |
| 769 | |
| 770 | tty_add_file(tty, filp); |
| 771 | |
| 772 | dentry = devpts_pty_new(fsi, index, tty->link); |
| 773 | if (IS_ERR(dentry)) { |
| 774 | retval = PTR_ERR(dentry); |
| 775 | goto err_release; |
| 776 | } |
| 777 | tty->link->driver_data = dentry; |
| 778 | |
| 779 | retval = ptm_driver->ops->open(tty, filp); |
| 780 | if (retval) |
| 781 | goto err_release; |
| 782 | |
| 783 | tty_debug_hangup(tty, "opening (count=%d)\n", tty->count); |
| 784 | |
| 785 | tty_unlock(tty); |
| 786 | return 0; |
| 787 | err_release: |
| 788 | tty_unlock(tty); |
| 789 | // This will also put-ref the fsi |
| 790 | tty_release(inode, filp); |
| 791 | return retval; |
| 792 | out: |
| 793 | devpts_kill_index(fsi, index); |
| 794 | out_put_ref: |
| 795 | devpts_put_ref(fsi); |
| 796 | out_free_file: |
| 797 | tty_free_file(filp); |
| 798 | return retval; |
| 799 | } |
| 800 | |
| 801 | static struct file_operations ptmx_fops; |
| 802 | |
| 803 | static void __init unix98_pty_init(void) |
| 804 | { |
| 805 | ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, |
| 806 | TTY_DRIVER_RESET_TERMIOS | |
| 807 | TTY_DRIVER_REAL_RAW | |
| 808 | TTY_DRIVER_DYNAMIC_DEV | |
| 809 | TTY_DRIVER_DEVPTS_MEM | |
| 810 | TTY_DRIVER_DYNAMIC_ALLOC); |
| 811 | if (IS_ERR(ptm_driver)) |
| 812 | panic("Couldn't allocate Unix98 ptm driver"); |
| 813 | pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX, |
| 814 | TTY_DRIVER_RESET_TERMIOS | |
| 815 | TTY_DRIVER_REAL_RAW | |
| 816 | TTY_DRIVER_DYNAMIC_DEV | |
| 817 | TTY_DRIVER_DEVPTS_MEM | |
| 818 | TTY_DRIVER_DYNAMIC_ALLOC); |
| 819 | if (IS_ERR(pts_driver)) |
| 820 | panic("Couldn't allocate Unix98 pts driver"); |
| 821 | |
| 822 | ptm_driver->driver_name = "pty_master"; |
| 823 | ptm_driver->name = "ptm"; |
| 824 | ptm_driver->major = UNIX98_PTY_MASTER_MAJOR; |
| 825 | ptm_driver->minor_start = 0; |
| 826 | ptm_driver->type = TTY_DRIVER_TYPE_PTY; |
| 827 | ptm_driver->subtype = PTY_TYPE_MASTER; |
| 828 | ptm_driver->init_termios = tty_std_termios; |
| 829 | ptm_driver->init_termios.c_iflag = 0; |
| 830 | ptm_driver->init_termios.c_oflag = 0; |
| 831 | ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
| 832 | ptm_driver->init_termios.c_lflag = 0; |
| 833 | ptm_driver->init_termios.c_ispeed = 38400; |
| 834 | ptm_driver->init_termios.c_ospeed = 38400; |
| 835 | ptm_driver->other = pts_driver; |
| 836 | tty_set_operations(ptm_driver, &ptm_unix98_ops); |
| 837 | |
| 838 | pts_driver->driver_name = "pty_slave"; |
| 839 | pts_driver->name = "pts"; |
| 840 | pts_driver->major = UNIX98_PTY_SLAVE_MAJOR; |
| 841 | pts_driver->minor_start = 0; |
| 842 | pts_driver->type = TTY_DRIVER_TYPE_PTY; |
| 843 | pts_driver->subtype = PTY_TYPE_SLAVE; |
| 844 | pts_driver->init_termios = tty_std_termios; |
| 845 | pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
| 846 | pts_driver->init_termios.c_ispeed = 38400; |
| 847 | pts_driver->init_termios.c_ospeed = 38400; |
| 848 | pts_driver->other = ptm_driver; |
| 849 | tty_set_operations(pts_driver, &pty_unix98_ops); |
| 850 | |
| 851 | if (tty_register_driver(ptm_driver)) |
| 852 | panic("Couldn't register Unix98 ptm driver"); |
| 853 | if (tty_register_driver(pts_driver)) |
| 854 | panic("Couldn't register Unix98 pts driver"); |
| 855 | |
| 856 | /* Now create the /dev/ptmx special device */ |
| 857 | tty_default_fops(&ptmx_fops); |
| 858 | ptmx_fops.open = ptmx_open; |
| 859 | |
| 860 | cdev_init(&ptmx_cdev, &ptmx_fops); |
| 861 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || |
| 862 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) |
| 863 | panic("Couldn't register /dev/ptmx driver"); |
| 864 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); |
| 865 | } |
| 866 | |
| 867 | #else |
| 868 | static inline void unix98_pty_init(void) { } |
| 869 | #endif |
| 870 | |
| 871 | static int __init pty_init(void) |
| 872 | { |
| 873 | legacy_pty_init(); |
| 874 | unix98_pty_init(); |
| 875 | return 0; |
| 876 | } |
| 877 | device_initcall(pty_init); |