| 1 | /* |
| 2 | * linux/drivers/char/pty.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | * |
| 6 | * Added support for a Unix98-style ptmx device. |
| 7 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 |
| 8 | * |
| 9 | * When reading this code see also fs/devpts. In particular note that the |
| 10 | * driver_data field is used by the devpts side as a binding to the devpts |
| 11 | * inode. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/module.h> |
| 15 | |
| 16 | #include <linux/errno.h> |
| 17 | #include <linux/interrupt.h> |
| 18 | #include <linux/tty.h> |
| 19 | #include <linux/tty_flip.h> |
| 20 | #include <linux/fcntl.h> |
| 21 | #include <linux/string.h> |
| 22 | #include <linux/major.h> |
| 23 | #include <linux/mm.h> |
| 24 | #include <linux/init.h> |
| 25 | #include <linux/smp_lock.h> |
| 26 | #include <linux/sysctl.h> |
| 27 | #include <linux/device.h> |
| 28 | #include <linux/uaccess.h> |
| 29 | #include <linux/bitops.h> |
| 30 | #include <linux/devpts_fs.h> |
| 31 | |
| 32 | #include <asm/system.h> |
| 33 | |
| 34 | #ifdef CONFIG_UNIX98_PTYS |
| 35 | static struct tty_driver *ptm_driver; |
| 36 | static struct tty_driver *pts_driver; |
| 37 | #endif |
| 38 | |
| 39 | static void pty_close(struct tty_struct *tty, struct file *filp) |
| 40 | { |
| 41 | BUG_ON(!tty); |
| 42 | if (tty->driver->subtype == PTY_TYPE_MASTER) |
| 43 | WARN_ON(tty->count > 1); |
| 44 | else { |
| 45 | if (tty->count > 2) |
| 46 | return; |
| 47 | } |
| 48 | wake_up_interruptible(&tty->read_wait); |
| 49 | wake_up_interruptible(&tty->write_wait); |
| 50 | tty->packet = 0; |
| 51 | if (!tty->link) |
| 52 | return; |
| 53 | tty->link->packet = 0; |
| 54 | set_bit(TTY_OTHER_CLOSED, &tty->link->flags); |
| 55 | wake_up_interruptible(&tty->link->read_wait); |
| 56 | wake_up_interruptible(&tty->link->write_wait); |
| 57 | if (tty->driver->subtype == PTY_TYPE_MASTER) { |
| 58 | set_bit(TTY_OTHER_CLOSED, &tty->flags); |
| 59 | #ifdef CONFIG_UNIX98_PTYS |
| 60 | if (tty->driver == ptm_driver) |
| 61 | devpts_pty_kill(tty->link); |
| 62 | #endif |
| 63 | tty_vhangup(tty->link); |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | /* |
| 68 | * The unthrottle routine is called by the line discipline to signal |
| 69 | * that it can receive more characters. For PTY's, the TTY_THROTTLED |
| 70 | * flag is always set, to force the line discipline to always call the |
| 71 | * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE |
| 72 | * characters in the queue. This is necessary since each time this |
| 73 | * happens, we need to wake up any sleeping processes that could be |
| 74 | * (1) trying to send data to the pty, or (2) waiting in wait_until_sent() |
| 75 | * for the pty buffer to be drained. |
| 76 | */ |
| 77 | static void pty_unthrottle(struct tty_struct *tty) |
| 78 | { |
| 79 | tty_wakeup(tty->link); |
| 80 | set_bit(TTY_THROTTLED, &tty->flags); |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * pty_space - report space left for writing |
| 85 | * @to: tty we are writing into |
| 86 | * |
| 87 | * The tty buffers allow 64K but we sneak a peak and clip at 8K this |
| 88 | * allows a lot of overspill room for echo and other fun messes to |
| 89 | * be handled properly |
| 90 | */ |
| 91 | |
| 92 | static int pty_space(struct tty_struct *to) |
| 93 | { |
| 94 | int n = 8192 - to->buf.memory_used; |
| 95 | if (n < 0) |
| 96 | return 0; |
| 97 | return n; |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * pty_write - write to a pty |
| 102 | * @tty: the tty we write from |
| 103 | * @buf: kernel buffer of data |
| 104 | * @count: bytes to write |
| 105 | * |
| 106 | * Our "hardware" write method. Data is coming from the ldisc which |
| 107 | * may be in a non sleeping state. We simply throw this at the other |
| 108 | * end of the link as if we were an IRQ handler receiving stuff for |
| 109 | * the other side of the pty/tty pair. |
| 110 | */ |
| 111 | |
| 112 | static int pty_write(struct tty_struct *tty, const unsigned char *buf, |
| 113 | int count) |
| 114 | { |
| 115 | struct tty_struct *to = tty->link; |
| 116 | int c; |
| 117 | |
| 118 | if (tty->stopped) |
| 119 | return 0; |
| 120 | |
| 121 | /* This isn't locked but our 8K is quite sloppy so no |
| 122 | big deal */ |
| 123 | |
| 124 | c = pty_space(to); |
| 125 | if (c > count) |
| 126 | c = count; |
| 127 | if (c > 0) { |
| 128 | /* Stuff the data into the input queue of the other end */ |
| 129 | c = tty_insert_flip_string(to, buf, c); |
| 130 | /* And shovel */ |
| 131 | tty_flip_buffer_push(to); |
| 132 | tty_wakeup(tty); |
| 133 | } |
| 134 | return c; |
| 135 | } |
| 136 | |
| 137 | /** |
| 138 | * pty_write_room - write space |
| 139 | * @tty: tty we are writing from |
| 140 | * |
| 141 | * Report how many bytes the ldisc can send into the queue for |
| 142 | * the other device. |
| 143 | */ |
| 144 | |
| 145 | static int pty_write_room(struct tty_struct *tty) |
| 146 | { |
| 147 | return pty_space(tty->link); |
| 148 | } |
| 149 | |
| 150 | /** |
| 151 | * pty_chars_in_buffer - characters currently in our tx queue |
| 152 | * @tty: our tty |
| 153 | * |
| 154 | * Report how much we have in the transmit queue. As everything is |
| 155 | * instantly at the other end this is easy to implement. |
| 156 | */ |
| 157 | |
| 158 | static int pty_chars_in_buffer(struct tty_struct *tty) |
| 159 | { |
| 160 | return 0; |
| 161 | } |
| 162 | |
| 163 | /* Set the lock flag on a pty */ |
| 164 | static int pty_set_lock(struct tty_struct *tty, int __user *arg) |
| 165 | { |
| 166 | int val; |
| 167 | if (get_user(val, arg)) |
| 168 | return -EFAULT; |
| 169 | if (val) |
| 170 | set_bit(TTY_PTY_LOCK, &tty->flags); |
| 171 | else |
| 172 | clear_bit(TTY_PTY_LOCK, &tty->flags); |
| 173 | return 0; |
| 174 | } |
| 175 | |
| 176 | static void pty_flush_buffer(struct tty_struct *tty) |
| 177 | { |
| 178 | struct tty_struct *to = tty->link; |
| 179 | unsigned long flags; |
| 180 | |
| 181 | if (!to) |
| 182 | return; |
| 183 | /* tty_buffer_flush(to); FIXME */ |
| 184 | if (to->packet) { |
| 185 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
| 186 | tty->ctrl_status |= TIOCPKT_FLUSHWRITE; |
| 187 | wake_up_interruptible(&to->read_wait); |
| 188 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
| 189 | } |
| 190 | } |
| 191 | |
| 192 | static int pty_open(struct tty_struct *tty, struct file *filp) |
| 193 | { |
| 194 | int retval = -ENODEV; |
| 195 | |
| 196 | if (!tty || !tty->link) |
| 197 | goto out; |
| 198 | |
| 199 | retval = -EIO; |
| 200 | if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) |
| 201 | goto out; |
| 202 | if (test_bit(TTY_PTY_LOCK, &tty->link->flags)) |
| 203 | goto out; |
| 204 | if (tty->link->count != 1) |
| 205 | goto out; |
| 206 | |
| 207 | clear_bit(TTY_OTHER_CLOSED, &tty->link->flags); |
| 208 | set_bit(TTY_THROTTLED, &tty->flags); |
| 209 | retval = 0; |
| 210 | out: |
| 211 | return retval; |
| 212 | } |
| 213 | |
| 214 | static void pty_set_termios(struct tty_struct *tty, |
| 215 | struct ktermios *old_termios) |
| 216 | { |
| 217 | tty->termios->c_cflag &= ~(CSIZE | PARENB); |
| 218 | tty->termios->c_cflag |= (CS8 | CREAD); |
| 219 | } |
| 220 | |
| 221 | /** |
| 222 | * pty_do_resize - resize event |
| 223 | * @tty: tty being resized |
| 224 | * @ws: window size being set. |
| 225 | * |
| 226 | * Update the termios variables and send the neccessary signals to |
| 227 | * peform a terminal resize correctly |
| 228 | */ |
| 229 | |
| 230 | int pty_resize(struct tty_struct *tty, struct winsize *ws) |
| 231 | { |
| 232 | struct pid *pgrp, *rpgrp; |
| 233 | unsigned long flags; |
| 234 | struct tty_struct *pty = tty->link; |
| 235 | |
| 236 | /* For a PTY we need to lock the tty side */ |
| 237 | mutex_lock(&tty->termios_mutex); |
| 238 | if (!memcmp(ws, &tty->winsize, sizeof(*ws))) |
| 239 | goto done; |
| 240 | |
| 241 | /* Get the PID values and reference them so we can |
| 242 | avoid holding the tty ctrl lock while sending signals. |
| 243 | We need to lock these individually however. */ |
| 244 | |
| 245 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
| 246 | pgrp = get_pid(tty->pgrp); |
| 247 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
| 248 | |
| 249 | spin_lock_irqsave(&pty->ctrl_lock, flags); |
| 250 | rpgrp = get_pid(pty->pgrp); |
| 251 | spin_unlock_irqrestore(&pty->ctrl_lock, flags); |
| 252 | |
| 253 | if (pgrp) |
| 254 | kill_pgrp(pgrp, SIGWINCH, 1); |
| 255 | if (rpgrp != pgrp && rpgrp) |
| 256 | kill_pgrp(rpgrp, SIGWINCH, 1); |
| 257 | |
| 258 | put_pid(pgrp); |
| 259 | put_pid(rpgrp); |
| 260 | |
| 261 | tty->winsize = *ws; |
| 262 | pty->winsize = *ws; /* Never used so will go away soon */ |
| 263 | done: |
| 264 | mutex_unlock(&tty->termios_mutex); |
| 265 | return 0; |
| 266 | } |
| 267 | |
| 268 | static int pty_install(struct tty_driver *driver, struct tty_struct *tty) |
| 269 | { |
| 270 | struct tty_struct *o_tty; |
| 271 | int idx = tty->index; |
| 272 | int retval; |
| 273 | |
| 274 | o_tty = alloc_tty_struct(); |
| 275 | if (!o_tty) |
| 276 | return -ENOMEM; |
| 277 | if (!try_module_get(driver->other->owner)) { |
| 278 | /* This cannot in fact currently happen */ |
| 279 | free_tty_struct(o_tty); |
| 280 | return -ENOMEM; |
| 281 | } |
| 282 | initialize_tty_struct(o_tty, driver->other, idx); |
| 283 | |
| 284 | /* We always use new tty termios data so we can do this |
| 285 | the easy way .. */ |
| 286 | retval = tty_init_termios(tty); |
| 287 | if (retval) |
| 288 | goto free_mem_out; |
| 289 | |
| 290 | retval = tty_init_termios(o_tty); |
| 291 | if (retval) { |
| 292 | tty_free_termios(tty); |
| 293 | goto free_mem_out; |
| 294 | } |
| 295 | |
| 296 | /* |
| 297 | * Everything allocated ... set up the o_tty structure. |
| 298 | */ |
| 299 | driver->other->ttys[idx] = o_tty; |
| 300 | tty_driver_kref_get(driver->other); |
| 301 | if (driver->subtype == PTY_TYPE_MASTER) |
| 302 | o_tty->count++; |
| 303 | /* Establish the links in both directions */ |
| 304 | tty->link = o_tty; |
| 305 | o_tty->link = tty; |
| 306 | |
| 307 | tty_driver_kref_get(driver); |
| 308 | tty->count++; |
| 309 | driver->ttys[idx] = tty; |
| 310 | return 0; |
| 311 | free_mem_out: |
| 312 | module_put(o_tty->driver->owner); |
| 313 | free_tty_struct(o_tty); |
| 314 | return -ENOMEM; |
| 315 | } |
| 316 | |
| 317 | |
| 318 | static const struct tty_operations pty_ops = { |
| 319 | .install = pty_install, |
| 320 | .open = pty_open, |
| 321 | .close = pty_close, |
| 322 | .write = pty_write, |
| 323 | .write_room = pty_write_room, |
| 324 | .flush_buffer = pty_flush_buffer, |
| 325 | .chars_in_buffer = pty_chars_in_buffer, |
| 326 | .unthrottle = pty_unthrottle, |
| 327 | .set_termios = pty_set_termios, |
| 328 | .resize = pty_resize |
| 329 | }; |
| 330 | |
| 331 | /* Traditional BSD devices */ |
| 332 | #ifdef CONFIG_LEGACY_PTYS |
| 333 | static struct tty_driver *pty_driver, *pty_slave_driver; |
| 334 | |
| 335 | static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file, |
| 336 | unsigned int cmd, unsigned long arg) |
| 337 | { |
| 338 | switch (cmd) { |
| 339 | case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ |
| 340 | return pty_set_lock(tty, (int __user *) arg); |
| 341 | } |
| 342 | return -ENOIOCTLCMD; |
| 343 | } |
| 344 | |
| 345 | static int legacy_count = CONFIG_LEGACY_PTY_COUNT; |
| 346 | module_param(legacy_count, int, 0); |
| 347 | |
| 348 | static const struct tty_operations pty_ops_bsd = { |
| 349 | .open = pty_open, |
| 350 | .close = pty_close, |
| 351 | .write = pty_write, |
| 352 | .write_room = pty_write_room, |
| 353 | .flush_buffer = pty_flush_buffer, |
| 354 | .chars_in_buffer = pty_chars_in_buffer, |
| 355 | .unthrottle = pty_unthrottle, |
| 356 | .set_termios = pty_set_termios, |
| 357 | .ioctl = pty_bsd_ioctl, |
| 358 | .resize = pty_resize |
| 359 | }; |
| 360 | |
| 361 | static void __init legacy_pty_init(void) |
| 362 | { |
| 363 | if (legacy_count <= 0) |
| 364 | return; |
| 365 | |
| 366 | pty_driver = alloc_tty_driver(legacy_count); |
| 367 | if (!pty_driver) |
| 368 | panic("Couldn't allocate pty driver"); |
| 369 | |
| 370 | pty_slave_driver = alloc_tty_driver(legacy_count); |
| 371 | if (!pty_slave_driver) |
| 372 | panic("Couldn't allocate pty slave driver"); |
| 373 | |
| 374 | pty_driver->owner = THIS_MODULE; |
| 375 | pty_driver->driver_name = "pty_master"; |
| 376 | pty_driver->name = "pty"; |
| 377 | pty_driver->major = PTY_MASTER_MAJOR; |
| 378 | pty_driver->minor_start = 0; |
| 379 | pty_driver->type = TTY_DRIVER_TYPE_PTY; |
| 380 | pty_driver->subtype = PTY_TYPE_MASTER; |
| 381 | pty_driver->init_termios = tty_std_termios; |
| 382 | pty_driver->init_termios.c_iflag = 0; |
| 383 | pty_driver->init_termios.c_oflag = 0; |
| 384 | pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
| 385 | pty_driver->init_termios.c_lflag = 0; |
| 386 | pty_driver->init_termios.c_ispeed = 38400; |
| 387 | pty_driver->init_termios.c_ospeed = 38400; |
| 388 | pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW; |
| 389 | pty_driver->other = pty_slave_driver; |
| 390 | tty_set_operations(pty_driver, &pty_ops); |
| 391 | |
| 392 | pty_slave_driver->owner = THIS_MODULE; |
| 393 | pty_slave_driver->driver_name = "pty_slave"; |
| 394 | pty_slave_driver->name = "ttyp"; |
| 395 | pty_slave_driver->major = PTY_SLAVE_MAJOR; |
| 396 | pty_slave_driver->minor_start = 0; |
| 397 | pty_slave_driver->type = TTY_DRIVER_TYPE_PTY; |
| 398 | pty_slave_driver->subtype = PTY_TYPE_SLAVE; |
| 399 | pty_slave_driver->init_termios = tty_std_termios; |
| 400 | pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
| 401 | pty_slave_driver->init_termios.c_ispeed = 38400; |
| 402 | pty_slave_driver->init_termios.c_ospeed = 38400; |
| 403 | pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS | |
| 404 | TTY_DRIVER_REAL_RAW; |
| 405 | pty_slave_driver->other = pty_driver; |
| 406 | tty_set_operations(pty_slave_driver, &pty_ops); |
| 407 | |
| 408 | if (tty_register_driver(pty_driver)) |
| 409 | panic("Couldn't register pty driver"); |
| 410 | if (tty_register_driver(pty_slave_driver)) |
| 411 | panic("Couldn't register pty slave driver"); |
| 412 | } |
| 413 | #else |
| 414 | static inline void legacy_pty_init(void) { } |
| 415 | #endif |
| 416 | |
| 417 | /* Unix98 devices */ |
| 418 | #ifdef CONFIG_UNIX98_PTYS |
| 419 | /* |
| 420 | * sysctl support for setting limits on the number of Unix98 ptys allocated. |
| 421 | * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly. |
| 422 | */ |
| 423 | int pty_limit = NR_UNIX98_PTY_DEFAULT; |
| 424 | static int pty_limit_min; |
| 425 | static int pty_limit_max = NR_UNIX98_PTY_MAX; |
| 426 | static int pty_count; |
| 427 | |
| 428 | static struct cdev ptmx_cdev; |
| 429 | |
| 430 | static struct ctl_table pty_table[] = { |
| 431 | { |
| 432 | .ctl_name = PTY_MAX, |
| 433 | .procname = "max", |
| 434 | .maxlen = sizeof(int), |
| 435 | .mode = 0644, |
| 436 | .data = &pty_limit, |
| 437 | .proc_handler = &proc_dointvec_minmax, |
| 438 | .strategy = &sysctl_intvec, |
| 439 | .extra1 = &pty_limit_min, |
| 440 | .extra2 = &pty_limit_max, |
| 441 | }, { |
| 442 | .ctl_name = PTY_NR, |
| 443 | .procname = "nr", |
| 444 | .maxlen = sizeof(int), |
| 445 | .mode = 0444, |
| 446 | .data = &pty_count, |
| 447 | .proc_handler = &proc_dointvec, |
| 448 | }, { |
| 449 | .ctl_name = 0 |
| 450 | } |
| 451 | }; |
| 452 | |
| 453 | static struct ctl_table pty_kern_table[] = { |
| 454 | { |
| 455 | .ctl_name = KERN_PTY, |
| 456 | .procname = "pty", |
| 457 | .mode = 0555, |
| 458 | .child = pty_table, |
| 459 | }, |
| 460 | {} |
| 461 | }; |
| 462 | |
| 463 | static struct ctl_table pty_root_table[] = { |
| 464 | { |
| 465 | .ctl_name = CTL_KERN, |
| 466 | .procname = "kernel", |
| 467 | .mode = 0555, |
| 468 | .child = pty_kern_table, |
| 469 | }, |
| 470 | {} |
| 471 | }; |
| 472 | |
| 473 | |
| 474 | static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file, |
| 475 | unsigned int cmd, unsigned long arg) |
| 476 | { |
| 477 | switch (cmd) { |
| 478 | case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */ |
| 479 | return pty_set_lock(tty, (int __user *)arg); |
| 480 | case TIOCGPTN: /* Get PT Number */ |
| 481 | return put_user(tty->index, (unsigned int __user *)arg); |
| 482 | } |
| 483 | |
| 484 | return -ENOIOCTLCMD; |
| 485 | } |
| 486 | |
| 487 | /** |
| 488 | * ptm_unix98_lookup - find a pty master |
| 489 | * @driver: ptm driver |
| 490 | * @idx: tty index |
| 491 | * |
| 492 | * Look up a pty master device. Called under the tty_mutex for now. |
| 493 | * This provides our locking. |
| 494 | */ |
| 495 | |
| 496 | static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, |
| 497 | struct inode *ptm_inode, int idx) |
| 498 | { |
| 499 | struct tty_struct *tty = devpts_get_tty(ptm_inode, idx); |
| 500 | if (tty) |
| 501 | tty = tty->link; |
| 502 | return tty; |
| 503 | } |
| 504 | |
| 505 | /** |
| 506 | * pts_unix98_lookup - find a pty slave |
| 507 | * @driver: pts driver |
| 508 | * @idx: tty index |
| 509 | * |
| 510 | * Look up a pty master device. Called under the tty_mutex for now. |
| 511 | * This provides our locking. |
| 512 | */ |
| 513 | |
| 514 | static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, |
| 515 | struct inode *pts_inode, int idx) |
| 516 | { |
| 517 | struct tty_struct *tty = devpts_get_tty(pts_inode, idx); |
| 518 | /* Master must be open before slave */ |
| 519 | if (!tty) |
| 520 | return ERR_PTR(-EIO); |
| 521 | return tty; |
| 522 | } |
| 523 | |
| 524 | static void pty_unix98_shutdown(struct tty_struct *tty) |
| 525 | { |
| 526 | /* We have our own method as we don't use the tty index */ |
| 527 | kfree(tty->termios); |
| 528 | } |
| 529 | |
| 530 | /* We have no need to install and remove our tty objects as devpts does all |
| 531 | the work for us */ |
| 532 | |
| 533 | static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) |
| 534 | { |
| 535 | struct tty_struct *o_tty; |
| 536 | int idx = tty->index; |
| 537 | |
| 538 | o_tty = alloc_tty_struct(); |
| 539 | if (!o_tty) |
| 540 | return -ENOMEM; |
| 541 | if (!try_module_get(driver->other->owner)) { |
| 542 | /* This cannot in fact currently happen */ |
| 543 | free_tty_struct(o_tty); |
| 544 | return -ENOMEM; |
| 545 | } |
| 546 | initialize_tty_struct(o_tty, driver->other, idx); |
| 547 | |
| 548 | tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL); |
| 549 | if (tty->termios == NULL) |
| 550 | goto free_mem_out; |
| 551 | *tty->termios = driver->init_termios; |
| 552 | tty->termios_locked = tty->termios + 1; |
| 553 | |
| 554 | o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL); |
| 555 | if (o_tty->termios == NULL) |
| 556 | goto free_mem_out; |
| 557 | *o_tty->termios = driver->other->init_termios; |
| 558 | o_tty->termios_locked = o_tty->termios + 1; |
| 559 | |
| 560 | tty_driver_kref_get(driver->other); |
| 561 | if (driver->subtype == PTY_TYPE_MASTER) |
| 562 | o_tty->count++; |
| 563 | /* Establish the links in both directions */ |
| 564 | tty->link = o_tty; |
| 565 | o_tty->link = tty; |
| 566 | /* |
| 567 | * All structures have been allocated, so now we install them. |
| 568 | * Failures after this point use release_tty to clean up, so |
| 569 | * there's no need to null out the local pointers. |
| 570 | */ |
| 571 | tty_driver_kref_get(driver); |
| 572 | tty->count++; |
| 573 | pty_count++; |
| 574 | return 0; |
| 575 | free_mem_out: |
| 576 | kfree(o_tty->termios); |
| 577 | module_put(o_tty->driver->owner); |
| 578 | free_tty_struct(o_tty); |
| 579 | kfree(tty->termios); |
| 580 | return -ENOMEM; |
| 581 | } |
| 582 | |
| 583 | static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) |
| 584 | { |
| 585 | pty_count--; |
| 586 | } |
| 587 | |
| 588 | static const struct tty_operations ptm_unix98_ops = { |
| 589 | .lookup = ptm_unix98_lookup, |
| 590 | .install = pty_unix98_install, |
| 591 | .remove = pty_unix98_remove, |
| 592 | .open = pty_open, |
| 593 | .close = pty_close, |
| 594 | .write = pty_write, |
| 595 | .write_room = pty_write_room, |
| 596 | .flush_buffer = pty_flush_buffer, |
| 597 | .chars_in_buffer = pty_chars_in_buffer, |
| 598 | .unthrottle = pty_unthrottle, |
| 599 | .set_termios = pty_set_termios, |
| 600 | .ioctl = pty_unix98_ioctl, |
| 601 | .shutdown = pty_unix98_shutdown, |
| 602 | .resize = pty_resize |
| 603 | }; |
| 604 | |
| 605 | static const struct tty_operations pty_unix98_ops = { |
| 606 | .lookup = pts_unix98_lookup, |
| 607 | .install = pty_unix98_install, |
| 608 | .remove = pty_unix98_remove, |
| 609 | .open = pty_open, |
| 610 | .close = pty_close, |
| 611 | .write = pty_write, |
| 612 | .write_room = pty_write_room, |
| 613 | .flush_buffer = pty_flush_buffer, |
| 614 | .chars_in_buffer = pty_chars_in_buffer, |
| 615 | .unthrottle = pty_unthrottle, |
| 616 | .set_termios = pty_set_termios, |
| 617 | .shutdown = pty_unix98_shutdown |
| 618 | }; |
| 619 | |
| 620 | /** |
| 621 | * ptmx_open - open a unix 98 pty master |
| 622 | * @inode: inode of device file |
| 623 | * @filp: file pointer to tty |
| 624 | * |
| 625 | * Allocate a unix98 pty master device from the ptmx driver. |
| 626 | * |
| 627 | * Locking: tty_mutex protects the init_dev work. tty->count should |
| 628 | * protect the rest. |
| 629 | * allocated_ptys_lock handles the list of free pty numbers |
| 630 | */ |
| 631 | |
| 632 | static int __ptmx_open(struct inode *inode, struct file *filp) |
| 633 | { |
| 634 | struct tty_struct *tty; |
| 635 | int retval; |
| 636 | int index; |
| 637 | |
| 638 | nonseekable_open(inode, filp); |
| 639 | |
| 640 | /* find a device that is not in use. */ |
| 641 | index = devpts_new_index(inode); |
| 642 | if (index < 0) |
| 643 | return index; |
| 644 | |
| 645 | mutex_lock(&tty_mutex); |
| 646 | tty = tty_init_dev(ptm_driver, index, 1); |
| 647 | mutex_unlock(&tty_mutex); |
| 648 | |
| 649 | if (IS_ERR(tty)) { |
| 650 | retval = PTR_ERR(tty); |
| 651 | goto out; |
| 652 | } |
| 653 | |
| 654 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ |
| 655 | filp->private_data = tty; |
| 656 | file_move(filp, &tty->tty_files); |
| 657 | |
| 658 | retval = devpts_pty_new(inode, tty->link); |
| 659 | if (retval) |
| 660 | goto out1; |
| 661 | |
| 662 | retval = ptm_driver->ops->open(tty, filp); |
| 663 | if (!retval) |
| 664 | return 0; |
| 665 | out1: |
| 666 | tty_release_dev(filp); |
| 667 | return retval; |
| 668 | out: |
| 669 | devpts_kill_index(inode, index); |
| 670 | return retval; |
| 671 | } |
| 672 | |
| 673 | static int ptmx_open(struct inode *inode, struct file *filp) |
| 674 | { |
| 675 | int ret; |
| 676 | |
| 677 | lock_kernel(); |
| 678 | ret = __ptmx_open(inode, filp); |
| 679 | unlock_kernel(); |
| 680 | return ret; |
| 681 | } |
| 682 | |
| 683 | static struct file_operations ptmx_fops; |
| 684 | |
| 685 | static void __init unix98_pty_init(void) |
| 686 | { |
| 687 | ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX); |
| 688 | if (!ptm_driver) |
| 689 | panic("Couldn't allocate Unix98 ptm driver"); |
| 690 | pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX); |
| 691 | if (!pts_driver) |
| 692 | panic("Couldn't allocate Unix98 pts driver"); |
| 693 | |
| 694 | ptm_driver->owner = THIS_MODULE; |
| 695 | ptm_driver->driver_name = "pty_master"; |
| 696 | ptm_driver->name = "ptm"; |
| 697 | ptm_driver->major = UNIX98_PTY_MASTER_MAJOR; |
| 698 | ptm_driver->minor_start = 0; |
| 699 | ptm_driver->type = TTY_DRIVER_TYPE_PTY; |
| 700 | ptm_driver->subtype = PTY_TYPE_MASTER; |
| 701 | ptm_driver->init_termios = tty_std_termios; |
| 702 | ptm_driver->init_termios.c_iflag = 0; |
| 703 | ptm_driver->init_termios.c_oflag = 0; |
| 704 | ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
| 705 | ptm_driver->init_termios.c_lflag = 0; |
| 706 | ptm_driver->init_termios.c_ispeed = 38400; |
| 707 | ptm_driver->init_termios.c_ospeed = 38400; |
| 708 | ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | |
| 709 | TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM; |
| 710 | ptm_driver->other = pts_driver; |
| 711 | tty_set_operations(ptm_driver, &ptm_unix98_ops); |
| 712 | |
| 713 | pts_driver->owner = THIS_MODULE; |
| 714 | pts_driver->driver_name = "pty_slave"; |
| 715 | pts_driver->name = "pts"; |
| 716 | pts_driver->major = UNIX98_PTY_SLAVE_MAJOR; |
| 717 | pts_driver->minor_start = 0; |
| 718 | pts_driver->type = TTY_DRIVER_TYPE_PTY; |
| 719 | pts_driver->subtype = PTY_TYPE_SLAVE; |
| 720 | pts_driver->init_termios = tty_std_termios; |
| 721 | pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD; |
| 722 | pts_driver->init_termios.c_ispeed = 38400; |
| 723 | pts_driver->init_termios.c_ospeed = 38400; |
| 724 | pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | |
| 725 | TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM; |
| 726 | pts_driver->other = ptm_driver; |
| 727 | tty_set_operations(pts_driver, &pty_unix98_ops); |
| 728 | |
| 729 | if (tty_register_driver(ptm_driver)) |
| 730 | panic("Couldn't register Unix98 ptm driver"); |
| 731 | if (tty_register_driver(pts_driver)) |
| 732 | panic("Couldn't register Unix98 pts driver"); |
| 733 | |
| 734 | register_sysctl_table(pty_root_table); |
| 735 | |
| 736 | /* Now create the /dev/ptmx special device */ |
| 737 | tty_default_fops(&ptmx_fops); |
| 738 | ptmx_fops.open = ptmx_open; |
| 739 | |
| 740 | cdev_init(&ptmx_cdev, &ptmx_fops); |
| 741 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || |
| 742 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) |
| 743 | panic("Couldn't register /dev/ptmx driver\n"); |
| 744 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); |
| 745 | } |
| 746 | |
| 747 | #else |
| 748 | static inline void unix98_pty_init(void) { } |
| 749 | #endif |
| 750 | |
| 751 | static int __init pty_init(void) |
| 752 | { |
| 753 | legacy_pty_init(); |
| 754 | unix98_pty_init(); |
| 755 | return 0; |
| 756 | } |
| 757 | module_init(pty_init); |