2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched/signal.h>
73 #include <linux/sched/task.h>
74 #include <linux/interrupt.h>
75 #include <linux/tty.h>
76 #include <linux/tty_driver.h>
77 #include <linux/tty_flip.h>
78 #include <linux/devpts_fs.h>
79 #include <linux/file.h>
80 #include <linux/fdtable.h>
81 #include <linux/console.h>
82 #include <linux/timer.h>
83 #include <linux/ctype.h>
86 #include <linux/string.h>
87 #include <linux/slab.h>
88 #include <linux/poll.h>
89 #include <linux/proc_fs.h>
90 #include <linux/init.h>
91 #include <linux/module.h>
92 #include <linux/device.h>
93 #include <linux/wait.h>
94 #include <linux/bitops.h>
95 #include <linux/delay.h>
96 #include <linux/seq_file.h>
97 #include <linux/serial.h>
98 #include <linux/ratelimit.h>
100 #include <linux/uaccess.h>
102 #include <linux/kbd_kern.h>
103 #include <linux/vt_kern.h>
104 #include <linux/selection.h>
106 #include <linux/kmod.h>
107 #include <linux/nsproxy.h>
109 #undef TTY_DEBUG_HANGUP
110 #ifdef TTY_DEBUG_HANGUP
111 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
113 # define tty_debug_hangup(tty, f, args...) do { } while (0)
116 #define TTY_PARANOIA_CHECK 1
117 #define CHECK_TTY_COUNT 1
119 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
120 .c_iflag = ICRNL | IXON,
121 .c_oflag = OPOST | ONLCR,
122 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
123 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
124 ECHOCTL | ECHOKE | IEXTEN,
128 /* .c_line = N_TTY, */
131 EXPORT_SYMBOL(tty_std_termios);
133 /* This list gets poked at by procfs and various bits of boot up code. This
134 could do with some rationalisation such as pulling the tty proc function
137 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
139 /* Mutex to protect creating and releasing a tty */
140 DEFINE_MUTEX(tty_mutex);
142 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
143 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
144 ssize_t redirected_tty_write(struct file *, const char __user *,
146 static unsigned int tty_poll(struct file *, poll_table *);
147 static int tty_open(struct inode *, struct file *);
148 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
150 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
153 #define tty_compat_ioctl NULL
155 static int __tty_fasync(int fd, struct file *filp, int on);
156 static int tty_fasync(int fd, struct file *filp, int on);
157 static void release_tty(struct tty_struct *tty, int idx);
160 * free_tty_struct - free a disused tty
161 * @tty: tty struct to free
163 * Free the write buffers, tty queue and tty memory itself.
165 * Locking: none. Must be called after tty is definitely unused
168 static void free_tty_struct(struct tty_struct *tty)
170 tty_ldisc_deinit(tty);
171 put_device(tty->dev);
172 kfree(tty->write_buf);
173 tty->magic = 0xDEADDEAD;
177 static inline struct tty_struct *file_tty(struct file *file)
179 return ((struct tty_file_private *)file->private_data)->tty;
182 int tty_alloc_file(struct file *file)
184 struct tty_file_private *priv;
186 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
190 file->private_data = priv;
195 /* Associate a new file with the tty structure */
196 void tty_add_file(struct tty_struct *tty, struct file *file)
198 struct tty_file_private *priv = file->private_data;
203 spin_lock(&tty->files_lock);
204 list_add(&priv->list, &tty->tty_files);
205 spin_unlock(&tty->files_lock);
209 * tty_free_file - free file->private_data
211 * This shall be used only for fail path handling when tty_add_file was not
214 void tty_free_file(struct file *file)
216 struct tty_file_private *priv = file->private_data;
218 file->private_data = NULL;
222 /* Delete file from its tty */
223 static void tty_del_file(struct file *file)
225 struct tty_file_private *priv = file->private_data;
226 struct tty_struct *tty = priv->tty;
228 spin_lock(&tty->files_lock);
229 list_del(&priv->list);
230 spin_unlock(&tty->files_lock);
235 * tty_name - return tty naming
236 * @tty: tty structure
238 * Convert a tty structure into a name. The name reflects the kernel
239 * naming policy and if udev is in use may not reflect user space
244 const char *tty_name(const struct tty_struct *tty)
246 if (!tty) /* Hmm. NULL pointer. That's fun. */
251 EXPORT_SYMBOL(tty_name);
253 const char *tty_driver_name(const struct tty_struct *tty)
255 if (!tty || !tty->driver)
257 return tty->driver->name;
260 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
263 #ifdef TTY_PARANOIA_CHECK
265 pr_warn("(%d:%d): %s: NULL tty\n",
266 imajor(inode), iminor(inode), routine);
269 if (tty->magic != TTY_MAGIC) {
270 pr_warn("(%d:%d): %s: bad magic number\n",
271 imajor(inode), iminor(inode), routine);
278 /* Caller must hold tty_lock */
279 static int check_tty_count(struct tty_struct *tty, const char *routine)
281 #ifdef CHECK_TTY_COUNT
285 spin_lock(&tty->files_lock);
286 list_for_each(p, &tty->tty_files) {
289 spin_unlock(&tty->files_lock);
290 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
291 tty->driver->subtype == PTY_TYPE_SLAVE &&
292 tty->link && tty->link->count)
294 if (tty->count != count) {
295 tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
296 routine, tty->count, count);
304 * get_tty_driver - find device of a tty
305 * @dev_t: device identifier
306 * @index: returns the index of the tty
308 * This routine returns a tty driver structure, given a device number
309 * and also passes back the index number.
311 * Locking: caller must hold tty_mutex
314 static struct tty_driver *get_tty_driver(dev_t device, int *index)
316 struct tty_driver *p;
318 list_for_each_entry(p, &tty_drivers, tty_drivers) {
319 dev_t base = MKDEV(p->major, p->minor_start);
320 if (device < base || device >= base + p->num)
322 *index = device - base;
323 return tty_driver_kref_get(p);
328 #ifdef CONFIG_CONSOLE_POLL
331 * tty_find_polling_driver - find device of a polled tty
332 * @name: name string to match
333 * @line: pointer to resulting tty line nr
335 * This routine returns a tty driver structure, given a name
336 * and the condition that the tty driver is capable of polled
339 struct tty_driver *tty_find_polling_driver(char *name, int *line)
341 struct tty_driver *p, *res = NULL;
346 for (str = name; *str; str++)
347 if ((*str >= '0' && *str <= '9') || *str == ',')
353 tty_line = simple_strtoul(str, &str, 10);
355 mutex_lock(&tty_mutex);
356 /* Search through the tty devices to look for a match */
357 list_for_each_entry(p, &tty_drivers, tty_drivers) {
358 if (strncmp(name, p->name, len) != 0)
366 if (tty_line >= 0 && tty_line < p->num && p->ops &&
367 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
368 res = tty_driver_kref_get(p);
373 mutex_unlock(&tty_mutex);
377 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
380 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
381 size_t count, loff_t *ppos)
386 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
387 size_t count, loff_t *ppos)
392 /* No kernel lock held - none needed ;) */
393 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
395 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
398 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
401 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
404 static long hung_up_tty_compat_ioctl(struct file *file,
405 unsigned int cmd, unsigned long arg)
407 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
410 static int hung_up_tty_fasync(int fd, struct file *file, int on)
415 static const struct file_operations tty_fops = {
420 .unlocked_ioctl = tty_ioctl,
421 .compat_ioctl = tty_compat_ioctl,
423 .release = tty_release,
424 .fasync = tty_fasync,
427 static const struct file_operations console_fops = {
430 .write = redirected_tty_write,
432 .unlocked_ioctl = tty_ioctl,
433 .compat_ioctl = tty_compat_ioctl,
435 .release = tty_release,
436 .fasync = tty_fasync,
439 static const struct file_operations hung_up_tty_fops = {
441 .read = hung_up_tty_read,
442 .write = hung_up_tty_write,
443 .poll = hung_up_tty_poll,
444 .unlocked_ioctl = hung_up_tty_ioctl,
445 .compat_ioctl = hung_up_tty_compat_ioctl,
446 .release = tty_release,
447 .fasync = hung_up_tty_fasync,
450 static DEFINE_SPINLOCK(redirect_lock);
451 static struct file *redirect;
454 * tty_wakeup - request more data
457 * Internal and external helper for wakeups of tty. This function
458 * informs the line discipline if present that the driver is ready
459 * to receive more output data.
462 void tty_wakeup(struct tty_struct *tty)
464 struct tty_ldisc *ld;
466 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
467 ld = tty_ldisc_ref(tty);
469 if (ld->ops->write_wakeup)
470 ld->ops->write_wakeup(tty);
474 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
477 EXPORT_SYMBOL_GPL(tty_wakeup);
480 * __tty_hangup - actual handler for hangup events
483 * This can be called by a "kworker" kernel thread. That is process
484 * synchronous but doesn't hold any locks, so we need to make sure we
485 * have the appropriate locks for what we're doing.
487 * The hangup event clears any pending redirections onto the hung up
488 * device. It ensures future writes will error and it does the needed
489 * line discipline hangup and signal delivery. The tty object itself
494 * redirect lock for undoing redirection
495 * file list lock for manipulating list of ttys
496 * tty_ldiscs_lock from called functions
497 * termios_rwsem resetting termios data
498 * tasklist_lock to walk task list for hangup event
499 * ->siglock to protect ->signal/->sighand
501 static void __tty_hangup(struct tty_struct *tty, int exit_session)
503 struct file *cons_filp = NULL;
504 struct file *filp, *f = NULL;
505 struct tty_file_private *priv;
506 int closecount = 0, n;
513 spin_lock(&redirect_lock);
514 if (redirect && file_tty(redirect) == tty) {
518 spin_unlock(&redirect_lock);
522 if (test_bit(TTY_HUPPED, &tty->flags)) {
527 /* inuse_filps is protected by the single tty lock,
528 this really needs to change if we want to flush the
529 workqueue with the lock held */
530 check_tty_count(tty, "tty_hangup");
532 spin_lock(&tty->files_lock);
533 /* This breaks for file handles being sent over AF_UNIX sockets ? */
534 list_for_each_entry(priv, &tty->tty_files, list) {
536 if (filp->f_op->write == redirected_tty_write)
538 if (filp->f_op->write != tty_write)
541 __tty_fasync(-1, filp, 0); /* can't block */
542 filp->f_op = &hung_up_tty_fops;
544 spin_unlock(&tty->files_lock);
546 refs = tty_signal_session_leader(tty, exit_session);
547 /* Account for the p->signal references we killed */
551 tty_ldisc_hangup(tty, cons_filp != NULL);
553 spin_lock_irq(&tty->ctrl_lock);
554 clear_bit(TTY_THROTTLED, &tty->flags);
555 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
556 put_pid(tty->session);
560 tty->ctrl_status = 0;
561 spin_unlock_irq(&tty->ctrl_lock);
564 * If one of the devices matches a console pointer, we
565 * cannot just call hangup() because that will cause
566 * tty->count and state->count to go out of sync.
567 * So we just call close() the right number of times.
571 for (n = 0; n < closecount; n++)
572 tty->ops->close(tty, cons_filp);
573 } else if (tty->ops->hangup)
574 tty->ops->hangup(tty);
576 * We don't want to have driver/ldisc interactions beyond the ones
577 * we did here. The driver layer expects no calls after ->hangup()
578 * from the ldisc side, which is now guaranteed.
580 set_bit(TTY_HUPPED, &tty->flags);
587 static void do_tty_hangup(struct work_struct *work)
589 struct tty_struct *tty =
590 container_of(work, struct tty_struct, hangup_work);
592 __tty_hangup(tty, 0);
596 * tty_hangup - trigger a hangup event
597 * @tty: tty to hangup
599 * A carrier loss (virtual or otherwise) has occurred on this like
600 * schedule a hangup sequence to run after this event.
603 void tty_hangup(struct tty_struct *tty)
605 tty_debug_hangup(tty, "hangup\n");
606 schedule_work(&tty->hangup_work);
609 EXPORT_SYMBOL(tty_hangup);
612 * tty_vhangup - process vhangup
613 * @tty: tty to hangup
615 * The user has asked via system call for the terminal to be hung up.
616 * We do this synchronously so that when the syscall returns the process
617 * is complete. That guarantee is necessary for security reasons.
620 void tty_vhangup(struct tty_struct *tty)
622 tty_debug_hangup(tty, "vhangup\n");
623 __tty_hangup(tty, 0);
626 EXPORT_SYMBOL(tty_vhangup);
630 * tty_vhangup_self - process vhangup for own ctty
632 * Perform a vhangup on the current controlling tty
635 void tty_vhangup_self(void)
637 struct tty_struct *tty;
639 tty = get_current_tty();
647 * tty_vhangup_session - hangup session leader exit
648 * @tty: tty to hangup
650 * The session leader is exiting and hanging up its controlling terminal.
651 * Every process in the foreground process group is signalled SIGHUP.
653 * We do this synchronously so that when the syscall returns the process
654 * is complete. That guarantee is necessary for security reasons.
657 void tty_vhangup_session(struct tty_struct *tty)
659 tty_debug_hangup(tty, "session hangup\n");
660 __tty_hangup(tty, 1);
664 * tty_hung_up_p - was tty hung up
665 * @filp: file pointer of tty
667 * Return true if the tty has been subject to a vhangup or a carrier
671 int tty_hung_up_p(struct file *filp)
673 return (filp && filp->f_op == &hung_up_tty_fops);
676 EXPORT_SYMBOL(tty_hung_up_p);
679 * stop_tty - propagate flow control
682 * Perform flow control to the driver. May be called
683 * on an already stopped device and will not re-call the driver
686 * This functionality is used by both the line disciplines for
687 * halting incoming flow and by the driver. It may therefore be
688 * called from any context, may be under the tty atomic_write_lock
695 void __stop_tty(struct tty_struct *tty)
704 void stop_tty(struct tty_struct *tty)
708 spin_lock_irqsave(&tty->flow_lock, flags);
710 spin_unlock_irqrestore(&tty->flow_lock, flags);
712 EXPORT_SYMBOL(stop_tty);
715 * start_tty - propagate flow control
718 * Start a tty that has been stopped if at all possible. If this
719 * tty was previous stopped and is now being started, the driver
720 * start method is invoked and the line discipline woken.
726 void __start_tty(struct tty_struct *tty)
728 if (!tty->stopped || tty->flow_stopped)
732 tty->ops->start(tty);
736 void start_tty(struct tty_struct *tty)
740 spin_lock_irqsave(&tty->flow_lock, flags);
742 spin_unlock_irqrestore(&tty->flow_lock, flags);
744 EXPORT_SYMBOL(start_tty);
746 static void tty_update_time(struct timespec *time)
748 unsigned long sec = get_seconds();
751 * We only care if the two values differ in anything other than the
752 * lower three bits (i.e every 8 seconds). If so, then we can update
753 * the time of the tty device, otherwise it could be construded as a
754 * security leak to let userspace know the exact timing of the tty.
756 if ((sec ^ time->tv_sec) & ~7)
761 * tty_read - read method for tty device files
762 * @file: pointer to tty file
764 * @count: size of user buffer
767 * Perform the read system call function on this terminal device. Checks
768 * for hung up devices before calling the line discipline method.
771 * Locks the line discipline internally while needed. Multiple
772 * read calls may be outstanding in parallel.
775 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
779 struct inode *inode = file_inode(file);
780 struct tty_struct *tty = file_tty(file);
781 struct tty_ldisc *ld;
783 if (tty_paranoia_check(tty, inode, "tty_read"))
785 if (!tty || tty_io_error(tty))
788 /* We want to wait for the line discipline to sort out in this
790 ld = tty_ldisc_ref_wait(tty);
792 return hung_up_tty_read(file, buf, count, ppos);
794 i = ld->ops->read(tty, file, buf, count);
800 tty_update_time(&inode->i_atime);
805 static void tty_write_unlock(struct tty_struct *tty)
807 mutex_unlock(&tty->atomic_write_lock);
808 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
811 static int tty_write_lock(struct tty_struct *tty, int ndelay)
813 if (!mutex_trylock(&tty->atomic_write_lock)) {
816 if (mutex_lock_interruptible(&tty->atomic_write_lock))
823 * Split writes up in sane blocksizes to avoid
824 * denial-of-service type attacks
826 static inline ssize_t do_tty_write(
827 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
828 struct tty_struct *tty,
830 const char __user *buf,
833 ssize_t ret, written = 0;
836 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
841 * We chunk up writes into a temporary buffer. This
842 * simplifies low-level drivers immensely, since they
843 * don't have locking issues and user mode accesses.
845 * But if TTY_NO_WRITE_SPLIT is set, we should use a
848 * The default chunk-size is 2kB, because the NTTY
849 * layer has problems with bigger chunks. It will
850 * claim to be able to handle more characters than
853 * FIXME: This can probably go away now except that 64K chunks
854 * are too likely to fail unless switched to vmalloc...
857 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
862 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
863 if (tty->write_cnt < chunk) {
864 unsigned char *buf_chunk;
869 buf_chunk = kmalloc(chunk, GFP_KERNEL);
874 kfree(tty->write_buf);
875 tty->write_cnt = chunk;
876 tty->write_buf = buf_chunk;
879 /* Do the write .. */
885 if (copy_from_user(tty->write_buf, buf, size))
887 ret = write(tty, file, tty->write_buf, size);
896 if (signal_pending(current))
901 tty_update_time(&file_inode(file)->i_mtime);
905 tty_write_unlock(tty);
910 * tty_write_message - write a message to a certain tty, not just the console.
911 * @tty: the destination tty_struct
912 * @msg: the message to write
914 * This is used for messages that need to be redirected to a specific tty.
915 * We don't put it into the syslog queue right now maybe in the future if
918 * We must still hold the BTM and test the CLOSING flag for the moment.
921 void tty_write_message(struct tty_struct *tty, char *msg)
924 mutex_lock(&tty->atomic_write_lock);
926 if (tty->ops->write && tty->count > 0)
927 tty->ops->write(tty, msg, strlen(msg));
929 tty_write_unlock(tty);
936 * tty_write - write method for tty device file
937 * @file: tty file pointer
938 * @buf: user data to write
939 * @count: bytes to write
942 * Write data to a tty device via the line discipline.
945 * Locks the line discipline as required
946 * Writes to the tty driver are serialized by the atomic_write_lock
947 * and are then processed in chunks to the device. The line discipline
948 * write method will not be invoked in parallel for each device.
951 static ssize_t tty_write(struct file *file, const char __user *buf,
952 size_t count, loff_t *ppos)
954 struct tty_struct *tty = file_tty(file);
955 struct tty_ldisc *ld;
958 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
960 if (!tty || !tty->ops->write || tty_io_error(tty))
962 /* Short term debug to catch buggy drivers */
963 if (tty->ops->write_room == NULL)
964 tty_err(tty, "missing write_room method\n");
965 ld = tty_ldisc_ref_wait(tty);
967 return hung_up_tty_write(file, buf, count, ppos);
971 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
976 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
977 size_t count, loff_t *ppos)
979 struct file *p = NULL;
981 spin_lock(&redirect_lock);
983 p = get_file(redirect);
984 spin_unlock(&redirect_lock);
988 res = vfs_write(p, buf, count, &p->f_pos);
992 return tty_write(file, buf, count, ppos);
996 * tty_send_xchar - send priority character
998 * Send a high priority character to the tty even if stopped
1000 * Locking: none for xchar method, write ordering for write method.
1003 int tty_send_xchar(struct tty_struct *tty, char ch)
1005 int was_stopped = tty->stopped;
1007 if (tty->ops->send_xchar) {
1008 down_read(&tty->termios_rwsem);
1009 tty->ops->send_xchar(tty, ch);
1010 up_read(&tty->termios_rwsem);
1014 if (tty_write_lock(tty, 0) < 0)
1015 return -ERESTARTSYS;
1017 down_read(&tty->termios_rwsem);
1020 tty->ops->write(tty, &ch, 1);
1023 up_read(&tty->termios_rwsem);
1024 tty_write_unlock(tty);
1028 static char ptychar[] = "pqrstuvwxyzabcde";
1031 * pty_line_name - generate name for a pty
1032 * @driver: the tty driver in use
1033 * @index: the minor number
1034 * @p: output buffer of at least 6 bytes
1036 * Generate a name from a driver reference and write it to the output
1041 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1043 int i = index + driver->name_base;
1044 /* ->name is initialized to "ttyp", but "tty" is expected */
1045 sprintf(p, "%s%c%x",
1046 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1047 ptychar[i >> 4 & 0xf], i & 0xf);
1051 * tty_line_name - generate name for a tty
1052 * @driver: the tty driver in use
1053 * @index: the minor number
1054 * @p: output buffer of at least 7 bytes
1056 * Generate a name from a driver reference and write it to the output
1061 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1063 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1064 return sprintf(p, "%s", driver->name);
1066 return sprintf(p, "%s%d", driver->name,
1067 index + driver->name_base);
1071 * tty_driver_lookup_tty() - find an existing tty, if any
1072 * @driver: the driver for the tty
1073 * @idx: the minor number
1075 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1076 * driver lookup() method returns an error.
1078 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1080 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1081 struct file *file, int idx)
1083 struct tty_struct *tty;
1085 if (driver->ops->lookup)
1086 tty = driver->ops->lookup(driver, file, idx);
1088 tty = driver->ttys[idx];
1096 * tty_init_termios - helper for termios setup
1097 * @tty: the tty to set up
1099 * Initialise the termios structures for this tty. Thus runs under
1100 * the tty_mutex currently so we can be relaxed about ordering.
1103 void tty_init_termios(struct tty_struct *tty)
1105 struct ktermios *tp;
1106 int idx = tty->index;
1108 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1109 tty->termios = tty->driver->init_termios;
1111 /* Check for lazy saved data */
1112 tp = tty->driver->termios[idx];
1115 tty->termios.c_line = tty->driver->init_termios.c_line;
1117 tty->termios = tty->driver->init_termios;
1119 /* Compatibility until drivers always set this */
1120 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1121 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1123 EXPORT_SYMBOL_GPL(tty_init_termios);
1125 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1127 tty_init_termios(tty);
1128 tty_driver_kref_get(driver);
1130 driver->ttys[tty->index] = tty;
1133 EXPORT_SYMBOL_GPL(tty_standard_install);
1136 * tty_driver_install_tty() - install a tty entry in the driver
1137 * @driver: the driver for the tty
1140 * Install a tty object into the driver tables. The tty->index field
1141 * will be set by the time this is called. This method is responsible
1142 * for ensuring any need additional structures are allocated and
1145 * Locking: tty_mutex for now
1147 static int tty_driver_install_tty(struct tty_driver *driver,
1148 struct tty_struct *tty)
1150 return driver->ops->install ? driver->ops->install(driver, tty) :
1151 tty_standard_install(driver, tty);
1155 * tty_driver_remove_tty() - remove a tty from the driver tables
1156 * @driver: the driver for the tty
1157 * @idx: the minor number
1159 * Remvoe a tty object from the driver tables. The tty->index field
1160 * will be set by the time this is called.
1162 * Locking: tty_mutex for now
1164 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1166 if (driver->ops->remove)
1167 driver->ops->remove(driver, tty);
1169 driver->ttys[tty->index] = NULL;
1173 * tty_reopen() - fast re-open of an open tty
1174 * @tty - the tty to open
1176 * Return 0 on success, -errno on error.
1177 * Re-opens on master ptys are not allowed and return -EIO.
1179 * Locking: Caller must hold tty_lock
1181 static int tty_reopen(struct tty_struct *tty)
1183 struct tty_driver *driver = tty->driver;
1185 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1186 driver->subtype == PTY_TYPE_MASTER)
1192 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1198 return tty_ldisc_reinit(tty, tty->termios.c_line);
1204 * tty_init_dev - initialise a tty device
1205 * @driver: tty driver we are opening a device on
1206 * @idx: device index
1207 * @ret_tty: returned tty structure
1209 * Prepare a tty device. This may not be a "new" clean device but
1210 * could also be an active device. The pty drivers require special
1211 * handling because of this.
1214 * The function is called under the tty_mutex, which
1215 * protects us from the tty struct or driver itself going away.
1217 * On exit the tty device has the line discipline attached and
1218 * a reference count of 1. If a pair was created for pty/tty use
1219 * and the other was a pty master then it too has a reference count of 1.
1221 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1222 * failed open. The new code protects the open with a mutex, so it's
1223 * really quite straightforward. The mutex locking can probably be
1224 * relaxed for the (most common) case of reopening a tty.
1227 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1229 struct tty_struct *tty;
1233 * First time open is complex, especially for PTY devices.
1234 * This code guarantees that either everything succeeds and the
1235 * TTY is ready for operation, or else the table slots are vacated
1236 * and the allocated memory released. (Except that the termios
1240 if (!try_module_get(driver->owner))
1241 return ERR_PTR(-ENODEV);
1243 tty = alloc_tty_struct(driver, idx);
1246 goto err_module_put;
1250 retval = tty_driver_install_tty(driver, tty);
1255 tty->port = driver->ports[idx];
1257 WARN_RATELIMIT(!tty->port,
1258 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1259 __func__, tty->driver->name);
1261 tty->port->itty = tty;
1264 * Structures all installed ... call the ldisc open routines.
1265 * If we fail here just call release_tty to clean up. No need
1266 * to decrement the use counts, as release_tty doesn't care.
1268 retval = tty_ldisc_setup(tty, tty->link);
1270 goto err_release_tty;
1271 /* Return the tty locked so that it cannot vanish under the caller */
1276 free_tty_struct(tty);
1278 module_put(driver->owner);
1279 return ERR_PTR(retval);
1281 /* call the tty release_tty routine to clean out this slot */
1284 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1286 release_tty(tty, idx);
1287 return ERR_PTR(retval);
1290 static void tty_free_termios(struct tty_struct *tty)
1292 struct ktermios *tp;
1293 int idx = tty->index;
1295 /* If the port is going to reset then it has no termios to save */
1296 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1299 /* Stash the termios data */
1300 tp = tty->driver->termios[idx];
1302 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1305 tty->driver->termios[idx] = tp;
1311 * tty_flush_works - flush all works of a tty/pty pair
1312 * @tty: tty device to flush works for (or either end of a pty pair)
1314 * Sync flush all works belonging to @tty (and the 'other' tty).
1316 static void tty_flush_works(struct tty_struct *tty)
1318 flush_work(&tty->SAK_work);
1319 flush_work(&tty->hangup_work);
1321 flush_work(&tty->link->SAK_work);
1322 flush_work(&tty->link->hangup_work);
1327 * release_one_tty - release tty structure memory
1328 * @kref: kref of tty we are obliterating
1330 * Releases memory associated with a tty structure, and clears out the
1331 * driver table slots. This function is called when a device is no longer
1332 * in use. It also gets called when setup of a device fails.
1335 * takes the file list lock internally when working on the list
1336 * of ttys that the driver keeps.
1338 * This method gets called from a work queue so that the driver private
1339 * cleanup ops can sleep (needed for USB at least)
1341 static void release_one_tty(struct work_struct *work)
1343 struct tty_struct *tty =
1344 container_of(work, struct tty_struct, hangup_work);
1345 struct tty_driver *driver = tty->driver;
1346 struct module *owner = driver->owner;
1348 if (tty->ops->cleanup)
1349 tty->ops->cleanup(tty);
1352 tty_driver_kref_put(driver);
1355 spin_lock(&tty->files_lock);
1356 list_del_init(&tty->tty_files);
1357 spin_unlock(&tty->files_lock);
1360 put_pid(tty->session);
1361 free_tty_struct(tty);
1364 static void queue_release_one_tty(struct kref *kref)
1366 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1368 /* The hangup queue is now free so we can reuse it rather than
1369 waste a chunk of memory for each port */
1370 INIT_WORK(&tty->hangup_work, release_one_tty);
1371 schedule_work(&tty->hangup_work);
1375 * tty_kref_put - release a tty kref
1378 * Release a reference to a tty device and if need be let the kref
1379 * layer destruct the object for us
1382 void tty_kref_put(struct tty_struct *tty)
1385 kref_put(&tty->kref, queue_release_one_tty);
1387 EXPORT_SYMBOL(tty_kref_put);
1390 * release_tty - release tty structure memory
1392 * Release both @tty and a possible linked partner (think pty pair),
1393 * and decrement the refcount of the backing module.
1397 * takes the file list lock internally when working on the list
1398 * of ttys that the driver keeps.
1401 static void release_tty(struct tty_struct *tty, int idx)
1403 /* This should always be true but check for the moment */
1404 WARN_ON(tty->index != idx);
1405 WARN_ON(!mutex_is_locked(&tty_mutex));
1406 if (tty->ops->shutdown)
1407 tty->ops->shutdown(tty);
1408 tty_free_termios(tty);
1409 tty_driver_remove_tty(tty->driver, tty);
1410 tty->port->itty = NULL;
1412 tty->link->port->itty = NULL;
1413 tty_buffer_cancel_work(tty->port);
1415 tty_kref_put(tty->link);
1420 * tty_release_checks - check a tty before real release
1421 * @tty: tty to check
1422 * @o_tty: link of @tty (if any)
1423 * @idx: index of the tty
1425 * Performs some paranoid checking before true release of the @tty.
1426 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1428 static int tty_release_checks(struct tty_struct *tty, int idx)
1430 #ifdef TTY_PARANOIA_CHECK
1431 if (idx < 0 || idx >= tty->driver->num) {
1432 tty_debug(tty, "bad idx %d\n", idx);
1436 /* not much to check for devpts */
1437 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1440 if (tty != tty->driver->ttys[idx]) {
1441 tty_debug(tty, "bad driver table[%d] = %p\n",
1442 idx, tty->driver->ttys[idx]);
1445 if (tty->driver->other) {
1446 struct tty_struct *o_tty = tty->link;
1448 if (o_tty != tty->driver->other->ttys[idx]) {
1449 tty_debug(tty, "bad other table[%d] = %p\n",
1450 idx, tty->driver->other->ttys[idx]);
1453 if (o_tty->link != tty) {
1454 tty_debug(tty, "bad link = %p\n", o_tty->link);
1463 * tty_release_struct - release a tty struct
1465 * @idx: index of the tty
1467 * Performs the final steps to release and free a tty device. It is
1468 * roughly the reverse of tty_init_dev.
1470 void tty_release_struct(struct tty_struct *tty, int idx)
1473 * Ask the line discipline code to release its structures
1475 tty_ldisc_release(tty);
1477 /* Wait for pending work before tty destruction commmences */
1478 tty_flush_works(tty);
1480 tty_debug_hangup(tty, "freeing structure\n");
1482 * The release_tty function takes care of the details of clearing
1483 * the slots and preserving the termios structure. The tty_unlock_pair
1484 * should be safe as we keep a kref while the tty is locked (so the
1485 * unlock never unlocks a freed tty).
1487 mutex_lock(&tty_mutex);
1488 release_tty(tty, idx);
1489 mutex_unlock(&tty_mutex);
1491 EXPORT_SYMBOL_GPL(tty_release_struct);
1494 * tty_release - vfs callback for close
1495 * @inode: inode of tty
1496 * @filp: file pointer for handle to tty
1498 * Called the last time each file handle is closed that references
1499 * this tty. There may however be several such references.
1502 * Takes bkl. See tty_release_dev
1504 * Even releasing the tty structures is a tricky business.. We have
1505 * to be very careful that the structures are all released at the
1506 * same time, as interrupts might otherwise get the wrong pointers.
1508 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1509 * lead to double frees or releasing memory still in use.
1512 int tty_release(struct inode *inode, struct file *filp)
1514 struct tty_struct *tty = file_tty(filp);
1515 struct tty_struct *o_tty = NULL;
1516 int do_sleep, final;
1521 if (tty_paranoia_check(tty, inode, __func__))
1525 check_tty_count(tty, __func__);
1527 __tty_fasync(-1, filp, 0);
1530 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1531 tty->driver->subtype == PTY_TYPE_MASTER)
1534 if (tty_release_checks(tty, idx)) {
1539 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1541 if (tty->ops->close)
1542 tty->ops->close(tty, filp);
1544 /* If tty is pty master, lock the slave pty (stable lock order) */
1545 tty_lock_slave(o_tty);
1548 * Sanity check: if tty->count is going to zero, there shouldn't be
1549 * any waiters on tty->read_wait or tty->write_wait. We test the
1550 * wait queues and kick everyone out _before_ actually starting to
1551 * close. This ensures that we won't block while releasing the tty
1554 * The test for the o_tty closing is necessary, since the master and
1555 * slave sides may close in any order. If the slave side closes out
1556 * first, its count will be one, since the master side holds an open.
1557 * Thus this test wouldn't be triggered at the time the slave closed,
1563 if (tty->count <= 1) {
1564 if (waitqueue_active(&tty->read_wait)) {
1565 wake_up_poll(&tty->read_wait, POLLIN);
1568 if (waitqueue_active(&tty->write_wait)) {
1569 wake_up_poll(&tty->write_wait, POLLOUT);
1573 if (o_tty && o_tty->count <= 1) {
1574 if (waitqueue_active(&o_tty->read_wait)) {
1575 wake_up_poll(&o_tty->read_wait, POLLIN);
1578 if (waitqueue_active(&o_tty->write_wait)) {
1579 wake_up_poll(&o_tty->write_wait, POLLOUT);
1588 tty_warn(tty, "read/write wait queue active!\n");
1590 schedule_timeout_killable(timeout);
1591 if (timeout < 120 * HZ)
1592 timeout = 2 * timeout + 1;
1594 timeout = MAX_SCHEDULE_TIMEOUT;
1598 if (--o_tty->count < 0) {
1599 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1603 if (--tty->count < 0) {
1604 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1609 * We've decremented tty->count, so we need to remove this file
1610 * descriptor off the tty->tty_files list; this serves two
1612 * - check_tty_count sees the correct number of file descriptors
1613 * associated with this tty.
1614 * - do_tty_hangup no longer sees this file descriptor as
1615 * something that needs to be handled for hangups.
1620 * Perform some housekeeping before deciding whether to return.
1622 * If _either_ side is closing, make sure there aren't any
1623 * processes that still think tty or o_tty is their controlling
1627 read_lock(&tasklist_lock);
1628 session_clear_tty(tty->session);
1630 session_clear_tty(o_tty->session);
1631 read_unlock(&tasklist_lock);
1634 /* check whether both sides are closing ... */
1635 final = !tty->count && !(o_tty && o_tty->count);
1637 tty_unlock_slave(o_tty);
1640 /* At this point, the tty->count == 0 should ensure a dead tty
1641 cannot be re-opened by a racing opener */
1646 tty_debug_hangup(tty, "final close\n");
1648 tty_release_struct(tty, idx);
1653 * tty_open_current_tty - get locked tty of current task
1654 * @device: device number
1655 * @filp: file pointer to tty
1656 * @return: locked tty of the current task iff @device is /dev/tty
1658 * Performs a re-open of the current task's controlling tty.
1660 * We cannot return driver and index like for the other nodes because
1661 * devpts will not work then. It expects inodes to be from devpts FS.
1663 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1665 struct tty_struct *tty;
1668 if (device != MKDEV(TTYAUX_MAJOR, 0))
1671 tty = get_current_tty();
1673 return ERR_PTR(-ENXIO);
1675 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1678 tty_kref_put(tty); /* safe to drop the kref now */
1680 retval = tty_reopen(tty);
1683 tty = ERR_PTR(retval);
1689 * tty_lookup_driver - lookup a tty driver for a given device file
1690 * @device: device number
1691 * @filp: file pointer to tty
1692 * @index: index for the device in the @return driver
1693 * @return: driver for this inode (with increased refcount)
1695 * If @return is not erroneous, the caller is responsible to decrement the
1696 * refcount by tty_driver_kref_put.
1698 * Locking: tty_mutex protects get_tty_driver
1700 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1703 struct tty_driver *driver;
1707 case MKDEV(TTY_MAJOR, 0): {
1708 extern struct tty_driver *console_driver;
1709 driver = tty_driver_kref_get(console_driver);
1710 *index = fg_console;
1714 case MKDEV(TTYAUX_MAJOR, 1): {
1715 struct tty_driver *console_driver = console_device(index);
1716 if (console_driver) {
1717 driver = tty_driver_kref_get(console_driver);
1719 /* Don't let /dev/console block */
1720 filp->f_flags |= O_NONBLOCK;
1724 return ERR_PTR(-ENODEV);
1727 driver = get_tty_driver(device, index);
1729 return ERR_PTR(-ENODEV);
1736 * tty_open_by_driver - open a tty device
1737 * @device: dev_t of device to open
1738 * @inode: inode of device file
1739 * @filp: file pointer to tty
1741 * Performs the driver lookup, checks for a reopen, or otherwise
1742 * performs the first-time tty initialization.
1744 * Returns the locked initialized or re-opened &tty_struct
1746 * Claims the global tty_mutex to serialize:
1747 * - concurrent first-time tty initialization
1748 * - concurrent tty driver removal w/ lookup
1749 * - concurrent tty removal from driver table
1751 static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
1754 struct tty_struct *tty;
1755 struct tty_driver *driver = NULL;
1759 mutex_lock(&tty_mutex);
1760 driver = tty_lookup_driver(device, filp, &index);
1761 if (IS_ERR(driver)) {
1762 mutex_unlock(&tty_mutex);
1763 return ERR_CAST(driver);
1766 /* check whether we're reopening an existing tty */
1767 tty = tty_driver_lookup_tty(driver, filp, index);
1769 mutex_unlock(&tty_mutex);
1774 mutex_unlock(&tty_mutex);
1775 retval = tty_lock_interruptible(tty);
1776 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
1778 if (retval == -EINTR)
1779 retval = -ERESTARTSYS;
1780 tty = ERR_PTR(retval);
1783 retval = tty_reopen(tty);
1786 tty = ERR_PTR(retval);
1788 } else { /* Returns with the tty_lock held for now */
1789 tty = tty_init_dev(driver, index);
1790 mutex_unlock(&tty_mutex);
1793 tty_driver_kref_put(driver);
1798 * tty_open - open a tty device
1799 * @inode: inode of device file
1800 * @filp: file pointer to tty
1802 * tty_open and tty_release keep up the tty count that contains the
1803 * number of opens done on a tty. We cannot use the inode-count, as
1804 * different inodes might point to the same tty.
1806 * Open-counting is needed for pty masters, as well as for keeping
1807 * track of serial lines: DTR is dropped when the last close happens.
1808 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1810 * The termios state of a pty is reset on first open so that
1811 * settings don't persist across reuse.
1813 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1814 * tty->count should protect the rest.
1815 * ->siglock protects ->signal/->sighand
1817 * Note: the tty_unlock/lock cases without a ref are only safe due to
1821 static int tty_open(struct inode *inode, struct file *filp)
1823 struct tty_struct *tty;
1825 dev_t device = inode->i_rdev;
1826 unsigned saved_flags = filp->f_flags;
1828 nonseekable_open(inode, filp);
1831 retval = tty_alloc_file(filp);
1835 tty = tty_open_current_tty(device, filp);
1837 tty = tty_open_by_driver(device, inode, filp);
1840 tty_free_file(filp);
1841 retval = PTR_ERR(tty);
1842 if (retval != -EAGAIN || signal_pending(current))
1848 tty_add_file(tty, filp);
1850 check_tty_count(tty, __func__);
1851 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
1854 retval = tty->ops->open(tty, filp);
1857 filp->f_flags = saved_flags;
1860 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
1862 tty_unlock(tty); /* need to call tty_release without BTM */
1863 tty_release(inode, filp);
1864 if (retval != -ERESTARTSYS)
1867 if (signal_pending(current))
1872 * Need to reset f_op in case a hangup happened.
1874 if (tty_hung_up_p(filp))
1875 filp->f_op = &tty_fops;
1878 clear_bit(TTY_HUPPED, &tty->flags);
1880 noctty = (filp->f_flags & O_NOCTTY) ||
1881 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
1882 device == MKDEV(TTYAUX_MAJOR, 1) ||
1883 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1884 tty->driver->subtype == PTY_TYPE_MASTER);
1886 tty_open_proc_set_tty(filp, tty);
1894 * tty_poll - check tty status
1895 * @filp: file being polled
1896 * @wait: poll wait structures to update
1898 * Call the line discipline polling method to obtain the poll
1899 * status of the device.
1901 * Locking: locks called line discipline but ldisc poll method
1902 * may be re-entered freely by other callers.
1905 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1907 struct tty_struct *tty = file_tty(filp);
1908 struct tty_ldisc *ld;
1911 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
1914 ld = tty_ldisc_ref_wait(tty);
1916 return hung_up_tty_poll(filp, wait);
1918 ret = ld->ops->poll(tty, filp, wait);
1919 tty_ldisc_deref(ld);
1923 static int __tty_fasync(int fd, struct file *filp, int on)
1925 struct tty_struct *tty = file_tty(filp);
1926 unsigned long flags;
1929 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
1932 retval = fasync_helper(fd, filp, on, &tty->fasync);
1940 spin_lock_irqsave(&tty->ctrl_lock, flags);
1943 type = PIDTYPE_PGID;
1945 pid = task_pid(current);
1949 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
1950 __f_setown(filp, pid, type, 0);
1958 static int tty_fasync(int fd, struct file *filp, int on)
1960 struct tty_struct *tty = file_tty(filp);
1961 int retval = -ENOTTY;
1964 if (!tty_hung_up_p(filp))
1965 retval = __tty_fasync(fd, filp, on);
1972 * tiocsti - fake input character
1973 * @tty: tty to fake input into
1974 * @p: pointer to character
1976 * Fake input to a tty device. Does the necessary locking and
1979 * FIXME: does not honour flow control ??
1982 * Called functions take tty_ldiscs_lock
1983 * current->signal->tty check is safe without locks
1985 * FIXME: may race normal receive processing
1988 static int tiocsti(struct tty_struct *tty, char __user *p)
1991 struct tty_ldisc *ld;
1993 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
1995 if (get_user(ch, p))
1997 tty_audit_tiocsti(tty, ch);
1998 ld = tty_ldisc_ref_wait(tty);
2001 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2002 tty_ldisc_deref(ld);
2007 * tiocgwinsz - implement window query ioctl
2009 * @arg: user buffer for result
2011 * Copies the kernel idea of the window size into the user buffer.
2013 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2017 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2021 mutex_lock(&tty->winsize_mutex);
2022 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2023 mutex_unlock(&tty->winsize_mutex);
2025 return err ? -EFAULT: 0;
2029 * tty_do_resize - resize event
2030 * @tty: tty being resized
2031 * @rows: rows (character)
2032 * @cols: cols (character)
2034 * Update the termios variables and send the necessary signals to
2035 * peform a terminal resize correctly
2038 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2043 mutex_lock(&tty->winsize_mutex);
2044 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2047 /* Signal the foreground process group */
2048 pgrp = tty_get_pgrp(tty);
2050 kill_pgrp(pgrp, SIGWINCH, 1);
2055 mutex_unlock(&tty->winsize_mutex);
2058 EXPORT_SYMBOL(tty_do_resize);
2061 * tiocswinsz - implement window size set ioctl
2062 * @tty; tty side of tty
2063 * @arg: user buffer for result
2065 * Copies the user idea of the window size to the kernel. Traditionally
2066 * this is just advisory information but for the Linux console it
2067 * actually has driver level meaning and triggers a VC resize.
2070 * Driver dependent. The default do_resize method takes the
2071 * tty termios mutex and ctrl_lock. The console takes its own lock
2072 * then calls into the default method.
2075 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2077 struct winsize tmp_ws;
2078 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2081 if (tty->ops->resize)
2082 return tty->ops->resize(tty, &tmp_ws);
2084 return tty_do_resize(tty, &tmp_ws);
2088 * tioccons - allow admin to move logical console
2089 * @file: the file to become console
2091 * Allow the administrator to move the redirected console device
2093 * Locking: uses redirect_lock to guard the redirect information
2096 static int tioccons(struct file *file)
2098 if (!capable(CAP_SYS_ADMIN))
2100 if (file->f_op->write == redirected_tty_write) {
2102 spin_lock(&redirect_lock);
2105 spin_unlock(&redirect_lock);
2110 spin_lock(&redirect_lock);
2112 spin_unlock(&redirect_lock);
2115 redirect = get_file(file);
2116 spin_unlock(&redirect_lock);
2121 * fionbio - non blocking ioctl
2122 * @file: file to set blocking value
2123 * @p: user parameter
2125 * Historical tty interfaces had a blocking control ioctl before
2126 * the generic functionality existed. This piece of history is preserved
2127 * in the expected tty API of posix OS's.
2129 * Locking: none, the open file handle ensures it won't go away.
2132 static int fionbio(struct file *file, int __user *p)
2136 if (get_user(nonblock, p))
2139 spin_lock(&file->f_lock);
2141 file->f_flags |= O_NONBLOCK;
2143 file->f_flags &= ~O_NONBLOCK;
2144 spin_unlock(&file->f_lock);
2149 * tiocsetd - set line discipline
2151 * @p: pointer to user data
2153 * Set the line discipline according to user request.
2155 * Locking: see tty_set_ldisc, this function is just a helper
2158 static int tiocsetd(struct tty_struct *tty, int __user *p)
2163 if (get_user(disc, p))
2166 ret = tty_set_ldisc(tty, disc);
2172 * tiocgetd - get line discipline
2174 * @p: pointer to user data
2176 * Retrieves the line discipline id directly from the ldisc.
2178 * Locking: waits for ldisc reference (in case the line discipline
2179 * is changing or the tty is being hungup)
2182 static int tiocgetd(struct tty_struct *tty, int __user *p)
2184 struct tty_ldisc *ld;
2187 ld = tty_ldisc_ref_wait(tty);
2190 ret = put_user(ld->ops->num, p);
2191 tty_ldisc_deref(ld);
2196 * send_break - performed time break
2197 * @tty: device to break on
2198 * @duration: timeout in mS
2200 * Perform a timed break on hardware that lacks its own driver level
2201 * timed break functionality.
2204 * atomic_write_lock serializes
2208 static int send_break(struct tty_struct *tty, unsigned int duration)
2212 if (tty->ops->break_ctl == NULL)
2215 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2216 retval = tty->ops->break_ctl(tty, duration);
2218 /* Do the work ourselves */
2219 if (tty_write_lock(tty, 0) < 0)
2221 retval = tty->ops->break_ctl(tty, -1);
2224 if (!signal_pending(current))
2225 msleep_interruptible(duration);
2226 retval = tty->ops->break_ctl(tty, 0);
2228 tty_write_unlock(tty);
2229 if (signal_pending(current))
2236 * tty_tiocmget - get modem status
2238 * @file: user file pointer
2239 * @p: pointer to result
2241 * Obtain the modem status bits from the tty driver if the feature
2242 * is supported. Return -EINVAL if it is not available.
2244 * Locking: none (up to the driver)
2247 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2249 int retval = -EINVAL;
2251 if (tty->ops->tiocmget) {
2252 retval = tty->ops->tiocmget(tty);
2255 retval = put_user(retval, p);
2261 * tty_tiocmset - set modem status
2263 * @cmd: command - clear bits, set bits or set all
2264 * @p: pointer to desired bits
2266 * Set the modem status bits from the tty driver if the feature
2267 * is supported. Return -EINVAL if it is not available.
2269 * Locking: none (up to the driver)
2272 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2276 unsigned int set, clear, val;
2278 if (tty->ops->tiocmset == NULL)
2281 retval = get_user(val, p);
2297 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2298 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2299 return tty->ops->tiocmset(tty, set, clear);
2302 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2304 int retval = -EINVAL;
2305 struct serial_icounter_struct icount;
2306 memset(&icount, 0, sizeof(icount));
2307 if (tty->ops->get_icount)
2308 retval = tty->ops->get_icount(tty, &icount);
2311 if (copy_to_user(arg, &icount, sizeof(icount)))
2316 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2318 static DEFINE_RATELIMIT_STATE(depr_flags,
2319 DEFAULT_RATELIMIT_INTERVAL,
2320 DEFAULT_RATELIMIT_BURST);
2321 char comm[TASK_COMM_LEN];
2324 if (get_user(flags, &ss->flags))
2327 flags &= ASYNC_DEPRECATED;
2329 if (flags && __ratelimit(&depr_flags))
2330 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2331 __func__, get_task_comm(comm, current), flags);
2335 * if pty, return the slave side (real_tty)
2336 * otherwise, return self
2338 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2340 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2341 tty->driver->subtype == PTY_TYPE_MASTER)
2347 * Split this up, as gcc can choke on it otherwise..
2349 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2351 struct tty_struct *tty = file_tty(file);
2352 struct tty_struct *real_tty;
2353 void __user *p = (void __user *)arg;
2355 struct tty_ldisc *ld;
2357 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2360 real_tty = tty_pair_get_tty(tty);
2363 * Factor out some common prep work
2371 retval = tty_check_change(tty);
2374 if (cmd != TIOCCBRK) {
2375 tty_wait_until_sent(tty, 0);
2376 if (signal_pending(current))
2387 return tiocsti(tty, p);
2389 return tiocgwinsz(real_tty, p);
2391 return tiocswinsz(real_tty, p);
2393 return real_tty != tty ? -EINVAL : tioccons(file);
2395 return fionbio(file, p);
2397 set_bit(TTY_EXCLUSIVE, &tty->flags);
2400 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2404 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2405 return put_user(excl, (int __user *)p);
2408 return tiocgetd(tty, p);
2410 return tiocsetd(tty, p);
2412 if (!capable(CAP_SYS_ADMIN))
2418 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2419 return put_user(ret, (unsigned int __user *)p);
2424 case TIOCSBRK: /* Turn break on, unconditionally */
2425 if (tty->ops->break_ctl)
2426 return tty->ops->break_ctl(tty, -1);
2428 case TIOCCBRK: /* Turn break off, unconditionally */
2429 if (tty->ops->break_ctl)
2430 return tty->ops->break_ctl(tty, 0);
2432 case TCSBRK: /* SVID version: non-zero arg --> no break */
2433 /* non-zero arg means wait for all output data
2434 * to be sent (performed above) but don't send break.
2435 * This is used by the tcdrain() termios function.
2438 return send_break(tty, 250);
2440 case TCSBRKP: /* support for POSIX tcsendbreak() */
2441 return send_break(tty, arg ? arg*100 : 250);
2444 return tty_tiocmget(tty, p);
2448 return tty_tiocmset(tty, cmd, p);
2450 retval = tty_tiocgicount(tty, p);
2451 /* For the moment allow fall through to the old method */
2452 if (retval != -EINVAL)
2459 /* flush tty buffer and allow ldisc to process ioctl */
2460 tty_buffer_flush(tty, NULL);
2465 tty_warn_deprecated_flags(p);
2468 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2469 if (retval != -ENOIOCTLCMD)
2472 if (tty->ops->ioctl) {
2473 retval = tty->ops->ioctl(tty, cmd, arg);
2474 if (retval != -ENOIOCTLCMD)
2477 ld = tty_ldisc_ref_wait(tty);
2479 return hung_up_tty_ioctl(file, cmd, arg);
2481 if (ld->ops->ioctl) {
2482 retval = ld->ops->ioctl(tty, file, cmd, arg);
2483 if (retval == -ENOIOCTLCMD)
2486 tty_ldisc_deref(ld);
2490 #ifdef CONFIG_COMPAT
2491 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2494 struct tty_struct *tty = file_tty(file);
2495 struct tty_ldisc *ld;
2496 int retval = -ENOIOCTLCMD;
2498 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2501 if (tty->ops->compat_ioctl) {
2502 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2503 if (retval != -ENOIOCTLCMD)
2507 ld = tty_ldisc_ref_wait(tty);
2509 return hung_up_tty_compat_ioctl(file, cmd, arg);
2510 if (ld->ops->compat_ioctl)
2511 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2513 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2514 tty_ldisc_deref(ld);
2520 static int this_tty(const void *t, struct file *file, unsigned fd)
2522 if (likely(file->f_op->read != tty_read))
2524 return file_tty(file) != t ? 0 : fd + 1;
2528 * This implements the "Secure Attention Key" --- the idea is to
2529 * prevent trojan horses by killing all processes associated with this
2530 * tty when the user hits the "Secure Attention Key". Required for
2531 * super-paranoid applications --- see the Orange Book for more details.
2533 * This code could be nicer; ideally it should send a HUP, wait a few
2534 * seconds, then send a INT, and then a KILL signal. But you then
2535 * have to coordinate with the init process, since all processes associated
2536 * with the current tty must be dead before the new getty is allowed
2539 * Now, if it would be correct ;-/ The current code has a nasty hole -
2540 * it doesn't catch files in flight. We may send the descriptor to ourselves
2541 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2543 * Nasty bug: do_SAK is being called in interrupt context. This can
2544 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2546 void __do_SAK(struct tty_struct *tty)
2551 struct task_struct *g, *p;
2552 struct pid *session;
2557 session = tty->session;
2559 tty_ldisc_flush(tty);
2561 tty_driver_flush_buffer(tty);
2563 read_lock(&tasklist_lock);
2564 /* Kill the entire session */
2565 do_each_pid_task(session, PIDTYPE_SID, p) {
2566 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
2567 task_pid_nr(p), p->comm);
2568 send_sig(SIGKILL, p, 1);
2569 } while_each_pid_task(session, PIDTYPE_SID, p);
2571 /* Now kill any processes that happen to have the tty open */
2572 do_each_thread(g, p) {
2573 if (p->signal->tty == tty) {
2574 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
2575 task_pid_nr(p), p->comm);
2576 send_sig(SIGKILL, p, 1);
2580 i = iterate_fd(p->files, 0, this_tty, tty);
2582 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
2583 task_pid_nr(p), p->comm, i - 1);
2584 force_sig(SIGKILL, p);
2587 } while_each_thread(g, p);
2588 read_unlock(&tasklist_lock);
2592 static void do_SAK_work(struct work_struct *work)
2594 struct tty_struct *tty =
2595 container_of(work, struct tty_struct, SAK_work);
2600 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2601 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2602 * the values which we write to it will be identical to the values which it
2603 * already has. --akpm
2605 void do_SAK(struct tty_struct *tty)
2609 schedule_work(&tty->SAK_work);
2612 EXPORT_SYMBOL(do_SAK);
2614 static int dev_match_devt(struct device *dev, const void *data)
2616 const dev_t *devt = data;
2617 return dev->devt == *devt;
2620 /* Must put_device() after it's unused! */
2621 static struct device *tty_get_device(struct tty_struct *tty)
2623 dev_t devt = tty_devnum(tty);
2624 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2631 * This subroutine allocates and initializes a tty structure.
2633 * Locking: none - tty in question is not exposed at this point
2636 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
2638 struct tty_struct *tty;
2640 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
2644 kref_init(&tty->kref);
2645 tty->magic = TTY_MAGIC;
2646 tty_ldisc_init(tty);
2647 tty->session = NULL;
2649 mutex_init(&tty->legacy_mutex);
2650 mutex_init(&tty->throttle_mutex);
2651 init_rwsem(&tty->termios_rwsem);
2652 mutex_init(&tty->winsize_mutex);
2653 init_ldsem(&tty->ldisc_sem);
2654 init_waitqueue_head(&tty->write_wait);
2655 init_waitqueue_head(&tty->read_wait);
2656 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2657 mutex_init(&tty->atomic_write_lock);
2658 spin_lock_init(&tty->ctrl_lock);
2659 spin_lock_init(&tty->flow_lock);
2660 spin_lock_init(&tty->files_lock);
2661 INIT_LIST_HEAD(&tty->tty_files);
2662 INIT_WORK(&tty->SAK_work, do_SAK_work);
2664 tty->driver = driver;
2665 tty->ops = driver->ops;
2667 tty_line_name(driver, idx, tty->name);
2668 tty->dev = tty_get_device(tty);
2674 * tty_put_char - write one character to a tty
2678 * Write one byte to the tty using the provided put_char method
2679 * if present. Returns the number of characters successfully output.
2681 * Note: the specific put_char operation in the driver layer may go
2682 * away soon. Don't call it directly, use this method
2685 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2687 if (tty->ops->put_char)
2688 return tty->ops->put_char(tty, ch);
2689 return tty->ops->write(tty, &ch, 1);
2691 EXPORT_SYMBOL_GPL(tty_put_char);
2693 struct class *tty_class;
2695 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
2696 unsigned int index, unsigned int count)
2700 /* init here, since reused cdevs cause crashes */
2701 driver->cdevs[index] = cdev_alloc();
2702 if (!driver->cdevs[index])
2704 driver->cdevs[index]->ops = &tty_fops;
2705 driver->cdevs[index]->owner = driver->owner;
2706 err = cdev_add(driver->cdevs[index], dev, count);
2708 kobject_put(&driver->cdevs[index]->kobj);
2713 * tty_register_device - register a tty device
2714 * @driver: the tty driver that describes the tty device
2715 * @index: the index in the tty driver for this tty device
2716 * @device: a struct device that is associated with this tty device.
2717 * This field is optional, if there is no known struct device
2718 * for this tty device it can be set to NULL safely.
2720 * Returns a pointer to the struct device for this tty device
2721 * (or ERR_PTR(-EFOO) on error).
2723 * This call is required to be made to register an individual tty device
2724 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2725 * that bit is not set, this function should not be called by a tty
2731 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2732 struct device *device)
2734 return tty_register_device_attr(driver, index, device, NULL, NULL);
2736 EXPORT_SYMBOL(tty_register_device);
2738 static void tty_device_create_release(struct device *dev)
2740 dev_dbg(dev, "releasing...\n");
2745 * tty_register_device_attr - register a tty device
2746 * @driver: the tty driver that describes the tty device
2747 * @index: the index in the tty driver for this tty device
2748 * @device: a struct device that is associated with this tty device.
2749 * This field is optional, if there is no known struct device
2750 * for this tty device it can be set to NULL safely.
2751 * @drvdata: Driver data to be set to device.
2752 * @attr_grp: Attribute group to be set on device.
2754 * Returns a pointer to the struct device for this tty device
2755 * (or ERR_PTR(-EFOO) on error).
2757 * This call is required to be made to register an individual tty device
2758 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2759 * that bit is not set, this function should not be called by a tty
2764 struct device *tty_register_device_attr(struct tty_driver *driver,
2765 unsigned index, struct device *device,
2767 const struct attribute_group **attr_grp)
2770 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
2771 struct ktermios *tp;
2775 if (index >= driver->num) {
2776 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
2777 driver->name, index);
2778 return ERR_PTR(-EINVAL);
2781 if (driver->type == TTY_DRIVER_TYPE_PTY)
2782 pty_line_name(driver, index, name);
2784 tty_line_name(driver, index, name);
2786 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2788 return ERR_PTR(-ENOMEM);
2791 dev->class = tty_class;
2792 dev->parent = device;
2793 dev->release = tty_device_create_release;
2794 dev_set_name(dev, "%s", name);
2795 dev->groups = attr_grp;
2796 dev_set_drvdata(dev, drvdata);
2798 dev_set_uevent_suppress(dev, 1);
2800 retval = device_register(dev);
2804 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
2806 * Free any saved termios data so that the termios state is
2807 * reset when reusing a minor number.
2809 tp = driver->termios[index];
2811 driver->termios[index] = NULL;
2815 retval = tty_cdev_add(driver, devt, index, 1);
2820 dev_set_uevent_suppress(dev, 0);
2821 kobject_uevent(&dev->kobj, KOBJ_ADD);
2830 return ERR_PTR(retval);
2832 EXPORT_SYMBOL_GPL(tty_register_device_attr);
2835 * tty_unregister_device - unregister a tty device
2836 * @driver: the tty driver that describes the tty device
2837 * @index: the index in the tty driver for this tty device
2839 * If a tty device is registered with a call to tty_register_device() then
2840 * this function must be called when the tty device is gone.
2845 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2847 device_destroy(tty_class,
2848 MKDEV(driver->major, driver->minor_start) + index);
2849 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
2850 cdev_del(driver->cdevs[index]);
2851 driver->cdevs[index] = NULL;
2854 EXPORT_SYMBOL(tty_unregister_device);
2857 * __tty_alloc_driver -- allocate tty driver
2858 * @lines: count of lines this driver can handle at most
2859 * @owner: module which is responsible for this driver
2860 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
2862 * This should not be called directly, some of the provided macros should be
2863 * used instead. Use IS_ERR and friends on @retval.
2865 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
2866 unsigned long flags)
2868 struct tty_driver *driver;
2869 unsigned int cdevs = 1;
2872 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
2873 return ERR_PTR(-EINVAL);
2875 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2877 return ERR_PTR(-ENOMEM);
2879 kref_init(&driver->kref);
2880 driver->magic = TTY_DRIVER_MAGIC;
2881 driver->num = lines;
2882 driver->owner = owner;
2883 driver->flags = flags;
2885 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
2886 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
2888 driver->termios = kcalloc(lines, sizeof(*driver->termios),
2890 if (!driver->ttys || !driver->termios) {
2896 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
2897 driver->ports = kcalloc(lines, sizeof(*driver->ports),
2899 if (!driver->ports) {
2906 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
2907 if (!driver->cdevs) {
2914 kfree(driver->ports);
2915 kfree(driver->ttys);
2916 kfree(driver->termios);
2917 kfree(driver->cdevs);
2919 return ERR_PTR(err);
2921 EXPORT_SYMBOL(__tty_alloc_driver);
2923 static void destruct_tty_driver(struct kref *kref)
2925 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2927 struct ktermios *tp;
2929 if (driver->flags & TTY_DRIVER_INSTALLED) {
2930 for (i = 0; i < driver->num; i++) {
2931 tp = driver->termios[i];
2933 driver->termios[i] = NULL;
2936 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2937 tty_unregister_device(driver, i);
2939 proc_tty_unregister_driver(driver);
2940 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
2941 cdev_del(driver->cdevs[0]);
2943 kfree(driver->cdevs);
2944 kfree(driver->ports);
2945 kfree(driver->termios);
2946 kfree(driver->ttys);
2950 void tty_driver_kref_put(struct tty_driver *driver)
2952 kref_put(&driver->kref, destruct_tty_driver);
2954 EXPORT_SYMBOL(tty_driver_kref_put);
2956 void tty_set_operations(struct tty_driver *driver,
2957 const struct tty_operations *op)
2961 EXPORT_SYMBOL(tty_set_operations);
2963 void put_tty_driver(struct tty_driver *d)
2965 tty_driver_kref_put(d);
2967 EXPORT_SYMBOL(put_tty_driver);
2970 * Called by a tty driver to register itself.
2972 int tty_register_driver(struct tty_driver *driver)
2979 if (!driver->major) {
2980 error = alloc_chrdev_region(&dev, driver->minor_start,
2981 driver->num, driver->name);
2983 driver->major = MAJOR(dev);
2984 driver->minor_start = MINOR(dev);
2987 dev = MKDEV(driver->major, driver->minor_start);
2988 error = register_chrdev_region(dev, driver->num, driver->name);
2993 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
2994 error = tty_cdev_add(driver, dev, 0, driver->num);
2996 goto err_unreg_char;
2999 mutex_lock(&tty_mutex);
3000 list_add(&driver->tty_drivers, &tty_drivers);
3001 mutex_unlock(&tty_mutex);
3003 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3004 for (i = 0; i < driver->num; i++) {
3005 d = tty_register_device(driver, i, NULL);
3008 goto err_unreg_devs;
3012 proc_tty_register_driver(driver);
3013 driver->flags |= TTY_DRIVER_INSTALLED;
3017 for (i--; i >= 0; i--)
3018 tty_unregister_device(driver, i);
3020 mutex_lock(&tty_mutex);
3021 list_del(&driver->tty_drivers);
3022 mutex_unlock(&tty_mutex);
3025 unregister_chrdev_region(dev, driver->num);
3029 EXPORT_SYMBOL(tty_register_driver);
3032 * Called by a tty driver to unregister itself.
3034 int tty_unregister_driver(struct tty_driver *driver)
3038 if (driver->refcount)
3041 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3043 mutex_lock(&tty_mutex);
3044 list_del(&driver->tty_drivers);
3045 mutex_unlock(&tty_mutex);
3049 EXPORT_SYMBOL(tty_unregister_driver);
3051 dev_t tty_devnum(struct tty_struct *tty)
3053 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3055 EXPORT_SYMBOL(tty_devnum);
3057 void tty_default_fops(struct file_operations *fops)
3062 static char *tty_devnode(struct device *dev, umode_t *mode)
3066 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3067 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3072 static int __init tty_class_init(void)
3074 tty_class = class_create(THIS_MODULE, "tty");
3075 if (IS_ERR(tty_class))
3076 return PTR_ERR(tty_class);
3077 tty_class->devnode = tty_devnode;
3081 postcore_initcall(tty_class_init);
3083 /* 3/2004 jmc: why do these devices exist? */
3084 static struct cdev tty_cdev, console_cdev;
3086 static ssize_t show_cons_active(struct device *dev,
3087 struct device_attribute *attr, char *buf)
3089 struct console *cs[16];
3095 for_each_console(c) {
3100 if ((c->flags & CON_ENABLED) == 0)
3103 if (i >= ARRAY_SIZE(cs))
3107 int index = cs[i]->index;
3108 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3110 /* don't resolve tty0 as some programs depend on it */
3111 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3112 count += tty_line_name(drv, index, buf + count);
3114 count += sprintf(buf + count, "%s%d",
3115 cs[i]->name, cs[i]->index);
3117 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3123 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3125 static struct attribute *cons_dev_attrs[] = {
3126 &dev_attr_active.attr,
3130 ATTRIBUTE_GROUPS(cons_dev);
3132 static struct device *consdev;
3134 void console_sysfs_notify(void)
3137 sysfs_notify(&consdev->kobj, NULL, "active");
3141 * Ok, now we can initialize the rest of the tty devices and can count
3142 * on memory allocations, interrupts etc..
3144 int __init tty_init(void)
3146 cdev_init(&tty_cdev, &tty_fops);
3147 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3148 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3149 panic("Couldn't register /dev/tty driver\n");
3150 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3152 cdev_init(&console_cdev, &console_fops);
3153 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3154 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3155 panic("Couldn't register /dev/console driver\n");
3156 consdev = device_create_with_groups(tty_class, NULL,
3157 MKDEV(TTYAUX_MAJOR, 1), NULL,
3158 cons_dev_groups, "console");
3159 if (IS_ERR(consdev))
3163 vty_init(&console_fops);