1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
8 * or rs-channels. It also implements echoing, cooked mode etc.
10 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
12 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
13 * tty_struct and tty_queue structures. Previously there was an array
14 * of 256 tty_struct's which was statically allocated, and the
15 * tty_queue structures were allocated at boot time. Both are now
16 * dynamically allocated only when the tty is open.
18 * Also restructured routines so that there is more of a separation
19 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
20 * the low-level tty routines (serial.c, pty.c, console.c). This
21 * makes for cleaner and more compact code. -TYT, 9/17/92
23 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
24 * which can be dynamically activated and de-activated by the line
25 * discipline handling modules (like SLIP).
27 * NOTE: pay no attention to the line discipline code (yet); its
28 * interface is still subject to change in this version...
31 * Added functionality to the OPOST tty handling. No delays, but all
32 * other bits should be there.
33 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
35 * Rewrote canonical mode and added more termios flags.
36 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
38 * Reorganized FASYNC support so mouse code can share it.
39 * -- ctm@ardi.com, 9Sep95
41 * New TIOCLINUX variants added.
42 * -- mj@k332.feld.cvut.cz, 19-Nov-95
44 * Restrict vt switching via ioctl()
45 * -- grif@cs.ucr.edu, 5-Dec-95
47 * Move console and virtual terminal code to more appropriate files,
48 * implement CONFIG_VT and generalize console device interface.
49 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
51 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
52 * -- Bill Hawes <whawes@star.net>, June 97
54 * Added devfs support.
55 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
57 * Added support for a Unix98-style ptmx device.
58 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
60 * Reduced memory usage for older ARM systems
61 * -- Russell King <rmk@arm.linux.org.uk>
63 * Move do_SAK() into process context. Less stack use in devfs functions.
64 * alloc_tty_struct() always uses kmalloc()
65 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
68 #include <linux/types.h>
69 #include <linux/major.h>
70 #include <linux/errno.h>
71 #include <linux/signal.h>
72 #include <linux/fcntl.h>
73 #include <linux/sched/signal.h>
74 #include <linux/sched/task.h>
75 #include <linux/interrupt.h>
76 #include <linux/tty.h>
77 #include <linux/tty_driver.h>
78 #include <linux/tty_flip.h>
79 #include <linux/devpts_fs.h>
80 #include <linux/file.h>
81 #include <linux/fdtable.h>
82 #include <linux/console.h>
83 #include <linux/timer.h>
84 #include <linux/ctype.h>
87 #include <linux/string.h>
88 #include <linux/slab.h>
89 #include <linux/poll.h>
90 #include <linux/proc_fs.h>
91 #include <linux/init.h>
92 #include <linux/module.h>
93 #include <linux/device.h>
94 #include <linux/wait.h>
95 #include <linux/bitops.h>
96 #include <linux/delay.h>
97 #include <linux/seq_file.h>
98 #include <linux/serial.h>
99 #include <linux/ratelimit.h>
100 #include <linux/compat.h>
102 #include <linux/uaccess.h>
104 #include <linux/kbd_kern.h>
105 #include <linux/vt_kern.h>
106 #include <linux/selection.h>
108 #include <linux/kmod.h>
109 #include <linux/nsproxy.h>
111 #undef TTY_DEBUG_HANGUP
112 #ifdef TTY_DEBUG_HANGUP
113 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
115 # define tty_debug_hangup(tty, f, args...) do { } while (0)
118 #define TTY_PARANOIA_CHECK 1
119 #define CHECK_TTY_COUNT 1
121 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
122 .c_iflag = ICRNL | IXON,
123 .c_oflag = OPOST | ONLCR,
124 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
125 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
126 ECHOCTL | ECHOKE | IEXTEN,
130 /* .c_line = N_TTY, */
133 EXPORT_SYMBOL(tty_std_termios);
135 /* This list gets poked at by procfs and various bits of boot up code. This
136 could do with some rationalisation such as pulling the tty proc function
139 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
141 /* Mutex to protect creating and releasing a tty */
142 DEFINE_MUTEX(tty_mutex);
144 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
145 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
146 ssize_t redirected_tty_write(struct file *, const char __user *,
148 static __poll_t tty_poll(struct file *, poll_table *);
149 static int tty_open(struct inode *, struct file *);
150 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
152 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
155 #define tty_compat_ioctl NULL
157 static int __tty_fasync(int fd, struct file *filp, int on);
158 static int tty_fasync(int fd, struct file *filp, int on);
159 static void release_tty(struct tty_struct *tty, int idx);
162 * free_tty_struct - free a disused tty
163 * @tty: tty struct to free
165 * Free the write buffers, tty queue and tty memory itself.
167 * Locking: none. Must be called after tty is definitely unused
170 static void free_tty_struct(struct tty_struct *tty)
172 tty_ldisc_deinit(tty);
173 put_device(tty->dev);
174 kfree(tty->write_buf);
175 tty->magic = 0xDEADDEAD;
179 static inline struct tty_struct *file_tty(struct file *file)
181 return ((struct tty_file_private *)file->private_data)->tty;
184 int tty_alloc_file(struct file *file)
186 struct tty_file_private *priv;
188 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
192 file->private_data = priv;
197 /* Associate a new file with the tty structure */
198 void tty_add_file(struct tty_struct *tty, struct file *file)
200 struct tty_file_private *priv = file->private_data;
205 spin_lock(&tty->files_lock);
206 list_add(&priv->list, &tty->tty_files);
207 spin_unlock(&tty->files_lock);
211 * tty_free_file - free file->private_data
213 * This shall be used only for fail path handling when tty_add_file was not
216 void tty_free_file(struct file *file)
218 struct tty_file_private *priv = file->private_data;
220 file->private_data = NULL;
224 /* Delete file from its tty */
225 static void tty_del_file(struct file *file)
227 struct tty_file_private *priv = file->private_data;
228 struct tty_struct *tty = priv->tty;
230 spin_lock(&tty->files_lock);
231 list_del(&priv->list);
232 spin_unlock(&tty->files_lock);
237 * tty_name - return tty naming
238 * @tty: tty structure
240 * Convert a tty structure into a name. The name reflects the kernel
241 * naming policy and if udev is in use may not reflect user space
246 const char *tty_name(const struct tty_struct *tty)
248 if (!tty) /* Hmm. NULL pointer. That's fun. */
253 EXPORT_SYMBOL(tty_name);
255 const char *tty_driver_name(const struct tty_struct *tty)
257 if (!tty || !tty->driver)
259 return tty->driver->name;
262 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
265 #ifdef TTY_PARANOIA_CHECK
267 pr_warn("(%d:%d): %s: NULL tty\n",
268 imajor(inode), iminor(inode), routine);
271 if (tty->magic != TTY_MAGIC) {
272 pr_warn("(%d:%d): %s: bad magic number\n",
273 imajor(inode), iminor(inode), routine);
280 /* Caller must hold tty_lock */
281 static int check_tty_count(struct tty_struct *tty, const char *routine)
283 #ifdef CHECK_TTY_COUNT
285 int count = 0, kopen_count = 0;
287 spin_lock(&tty->files_lock);
288 list_for_each(p, &tty->tty_files) {
291 spin_unlock(&tty->files_lock);
292 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
293 tty->driver->subtype == PTY_TYPE_SLAVE &&
294 tty->link && tty->link->count)
296 if (tty_port_kopened(tty->port))
298 if (tty->count != (count + kopen_count)) {
299 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
300 routine, tty->count, count, kopen_count);
301 return (count + kopen_count);
308 * get_tty_driver - find device of a tty
309 * @dev_t: device identifier
310 * @index: returns the index of the tty
312 * This routine returns a tty driver structure, given a device number
313 * and also passes back the index number.
315 * Locking: caller must hold tty_mutex
318 static struct tty_driver *get_tty_driver(dev_t device, int *index)
320 struct tty_driver *p;
322 list_for_each_entry(p, &tty_drivers, tty_drivers) {
323 dev_t base = MKDEV(p->major, p->minor_start);
324 if (device < base || device >= base + p->num)
326 *index = device - base;
327 return tty_driver_kref_get(p);
333 * tty_dev_name_to_number - return dev_t for device name
334 * @name: user space name of device under /dev
335 * @number: pointer to dev_t that this function will populate
337 * This function converts device names like ttyS0 or ttyUSB1 into dev_t
338 * like (4, 64) or (188, 1). If no corresponding driver is registered then
339 * the function returns -ENODEV.
341 * Locking: this acquires tty_mutex to protect the tty_drivers list from
342 * being modified while we are traversing it, and makes sure to
343 * release it before exiting.
345 int tty_dev_name_to_number(const char *name, dev_t *number)
347 struct tty_driver *p;
349 int index, prefix_length = 0;
352 for (str = name; *str && !isdigit(*str); str++)
358 ret = kstrtoint(str, 10, &index);
362 prefix_length = str - name;
363 mutex_lock(&tty_mutex);
365 list_for_each_entry(p, &tty_drivers, tty_drivers)
366 if (prefix_length == strlen(p->name) && strncmp(name,
367 p->name, prefix_length) == 0) {
368 if (index < p->num) {
369 *number = MKDEV(p->major, p->minor_start + index);
374 /* if here then driver wasn't found */
377 mutex_unlock(&tty_mutex);
380 EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
382 #ifdef CONFIG_CONSOLE_POLL
385 * tty_find_polling_driver - find device of a polled tty
386 * @name: name string to match
387 * @line: pointer to resulting tty line nr
389 * This routine returns a tty driver structure, given a name
390 * and the condition that the tty driver is capable of polled
393 struct tty_driver *tty_find_polling_driver(char *name, int *line)
395 struct tty_driver *p, *res = NULL;
400 for (str = name; *str; str++)
401 if ((*str >= '0' && *str <= '9') || *str == ',')
407 tty_line = simple_strtoul(str, &str, 10);
409 mutex_lock(&tty_mutex);
410 /* Search through the tty devices to look for a match */
411 list_for_each_entry(p, &tty_drivers, tty_drivers) {
412 if (!len || strncmp(name, p->name, len) != 0)
420 if (tty_line >= 0 && tty_line < p->num && p->ops &&
421 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
422 res = tty_driver_kref_get(p);
427 mutex_unlock(&tty_mutex);
431 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
434 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
435 size_t count, loff_t *ppos)
440 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
441 size_t count, loff_t *ppos)
446 /* No kernel lock held - none needed ;) */
447 static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
449 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
452 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
455 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
458 static long hung_up_tty_compat_ioctl(struct file *file,
459 unsigned int cmd, unsigned long arg)
461 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
464 static int hung_up_tty_fasync(int fd, struct file *file, int on)
469 static void tty_show_fdinfo(struct seq_file *m, struct file *file)
471 struct tty_struct *tty = file_tty(file);
473 if (tty && tty->ops && tty->ops->show_fdinfo)
474 tty->ops->show_fdinfo(tty, m);
477 static const struct file_operations tty_fops = {
482 .unlocked_ioctl = tty_ioctl,
483 .compat_ioctl = tty_compat_ioctl,
485 .release = tty_release,
486 .fasync = tty_fasync,
487 .show_fdinfo = tty_show_fdinfo,
490 static const struct file_operations console_fops = {
493 .write = redirected_tty_write,
495 .unlocked_ioctl = tty_ioctl,
496 .compat_ioctl = tty_compat_ioctl,
498 .release = tty_release,
499 .fasync = tty_fasync,
502 static const struct file_operations hung_up_tty_fops = {
504 .read = hung_up_tty_read,
505 .write = hung_up_tty_write,
506 .poll = hung_up_tty_poll,
507 .unlocked_ioctl = hung_up_tty_ioctl,
508 .compat_ioctl = hung_up_tty_compat_ioctl,
509 .release = tty_release,
510 .fasync = hung_up_tty_fasync,
513 static DEFINE_SPINLOCK(redirect_lock);
514 static struct file *redirect;
516 extern void tty_sysctl_init(void);
519 * tty_wakeup - request more data
522 * Internal and external helper for wakeups of tty. This function
523 * informs the line discipline if present that the driver is ready
524 * to receive more output data.
527 void tty_wakeup(struct tty_struct *tty)
529 struct tty_ldisc *ld;
531 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
532 ld = tty_ldisc_ref(tty);
534 if (ld->ops->write_wakeup)
535 ld->ops->write_wakeup(tty);
539 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
542 EXPORT_SYMBOL_GPL(tty_wakeup);
545 * __tty_hangup - actual handler for hangup events
548 * This can be called by a "kworker" kernel thread. That is process
549 * synchronous but doesn't hold any locks, so we need to make sure we
550 * have the appropriate locks for what we're doing.
552 * The hangup event clears any pending redirections onto the hung up
553 * device. It ensures future writes will error and it does the needed
554 * line discipline hangup and signal delivery. The tty object itself
559 * redirect lock for undoing redirection
560 * file list lock for manipulating list of ttys
561 * tty_ldiscs_lock from called functions
562 * termios_rwsem resetting termios data
563 * tasklist_lock to walk task list for hangup event
564 * ->siglock to protect ->signal/->sighand
566 static void __tty_hangup(struct tty_struct *tty, int exit_session)
568 struct file *cons_filp = NULL;
569 struct file *filp, *f = NULL;
570 struct tty_file_private *priv;
571 int closecount = 0, n;
578 spin_lock(&redirect_lock);
579 if (redirect && file_tty(redirect) == tty) {
583 spin_unlock(&redirect_lock);
587 if (test_bit(TTY_HUPPED, &tty->flags)) {
593 * Some console devices aren't actually hung up for technical and
594 * historical reasons, which can lead to indefinite interruptible
595 * sleep in n_tty_read(). The following explicitly tells
596 * n_tty_read() to abort readers.
598 set_bit(TTY_HUPPING, &tty->flags);
600 /* inuse_filps is protected by the single tty lock,
601 this really needs to change if we want to flush the
602 workqueue with the lock held */
603 check_tty_count(tty, "tty_hangup");
605 spin_lock(&tty->files_lock);
606 /* This breaks for file handles being sent over AF_UNIX sockets ? */
607 list_for_each_entry(priv, &tty->tty_files, list) {
609 if (filp->f_op->write == redirected_tty_write)
611 if (filp->f_op->write != tty_write)
614 __tty_fasync(-1, filp, 0); /* can't block */
615 filp->f_op = &hung_up_tty_fops;
617 spin_unlock(&tty->files_lock);
619 refs = tty_signal_session_leader(tty, exit_session);
620 /* Account for the p->signal references we killed */
624 tty_ldisc_hangup(tty, cons_filp != NULL);
626 spin_lock_irq(&tty->ctrl_lock);
627 clear_bit(TTY_THROTTLED, &tty->flags);
628 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
629 put_pid(tty->session);
633 tty->ctrl_status = 0;
634 spin_unlock_irq(&tty->ctrl_lock);
637 * If one of the devices matches a console pointer, we
638 * cannot just call hangup() because that will cause
639 * tty->count and state->count to go out of sync.
640 * So we just call close() the right number of times.
644 for (n = 0; n < closecount; n++)
645 tty->ops->close(tty, cons_filp);
646 } else if (tty->ops->hangup)
647 tty->ops->hangup(tty);
649 * We don't want to have driver/ldisc interactions beyond the ones
650 * we did here. The driver layer expects no calls after ->hangup()
651 * from the ldisc side, which is now guaranteed.
653 set_bit(TTY_HUPPED, &tty->flags);
654 clear_bit(TTY_HUPPING, &tty->flags);
661 static void do_tty_hangup(struct work_struct *work)
663 struct tty_struct *tty =
664 container_of(work, struct tty_struct, hangup_work);
666 __tty_hangup(tty, 0);
670 * tty_hangup - trigger a hangup event
671 * @tty: tty to hangup
673 * A carrier loss (virtual or otherwise) has occurred on this like
674 * schedule a hangup sequence to run after this event.
677 void tty_hangup(struct tty_struct *tty)
679 tty_debug_hangup(tty, "hangup\n");
680 schedule_work(&tty->hangup_work);
683 EXPORT_SYMBOL(tty_hangup);
686 * tty_vhangup - process vhangup
687 * @tty: tty to hangup
689 * The user has asked via system call for the terminal to be hung up.
690 * We do this synchronously so that when the syscall returns the process
691 * is complete. That guarantee is necessary for security reasons.
694 void tty_vhangup(struct tty_struct *tty)
696 tty_debug_hangup(tty, "vhangup\n");
697 __tty_hangup(tty, 0);
700 EXPORT_SYMBOL(tty_vhangup);
704 * tty_vhangup_self - process vhangup for own ctty
706 * Perform a vhangup on the current controlling tty
709 void tty_vhangup_self(void)
711 struct tty_struct *tty;
713 tty = get_current_tty();
721 * tty_vhangup_session - hangup session leader exit
722 * @tty: tty to hangup
724 * The session leader is exiting and hanging up its controlling terminal.
725 * Every process in the foreground process group is signalled SIGHUP.
727 * We do this synchronously so that when the syscall returns the process
728 * is complete. That guarantee is necessary for security reasons.
731 void tty_vhangup_session(struct tty_struct *tty)
733 tty_debug_hangup(tty, "session hangup\n");
734 __tty_hangup(tty, 1);
738 * tty_hung_up_p - was tty hung up
739 * @filp: file pointer of tty
741 * Return true if the tty has been subject to a vhangup or a carrier
745 int tty_hung_up_p(struct file *filp)
747 return (filp && filp->f_op == &hung_up_tty_fops);
750 EXPORT_SYMBOL(tty_hung_up_p);
753 * stop_tty - propagate flow control
756 * Perform flow control to the driver. May be called
757 * on an already stopped device and will not re-call the driver
760 * This functionality is used by both the line disciplines for
761 * halting incoming flow and by the driver. It may therefore be
762 * called from any context, may be under the tty atomic_write_lock
769 void __stop_tty(struct tty_struct *tty)
778 void stop_tty(struct tty_struct *tty)
782 spin_lock_irqsave(&tty->flow_lock, flags);
784 spin_unlock_irqrestore(&tty->flow_lock, flags);
786 EXPORT_SYMBOL(stop_tty);
789 * start_tty - propagate flow control
792 * Start a tty that has been stopped if at all possible. If this
793 * tty was previous stopped and is now being started, the driver
794 * start method is invoked and the line discipline woken.
800 void __start_tty(struct tty_struct *tty)
802 if (!tty->stopped || tty->flow_stopped)
806 tty->ops->start(tty);
810 void start_tty(struct tty_struct *tty)
814 spin_lock_irqsave(&tty->flow_lock, flags);
816 spin_unlock_irqrestore(&tty->flow_lock, flags);
818 EXPORT_SYMBOL(start_tty);
820 static void tty_update_time(struct timespec64 *time)
822 time64_t sec = ktime_get_real_seconds();
825 * We only care if the two values differ in anything other than the
826 * lower three bits (i.e every 8 seconds). If so, then we can update
827 * the time of the tty device, otherwise it could be construded as a
828 * security leak to let userspace know the exact timing of the tty.
830 if ((sec ^ time->tv_sec) & ~7)
835 * tty_read - read method for tty device files
836 * @file: pointer to tty file
838 * @count: size of user buffer
841 * Perform the read system call function on this terminal device. Checks
842 * for hung up devices before calling the line discipline method.
845 * Locks the line discipline internally while needed. Multiple
846 * read calls may be outstanding in parallel.
849 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
853 struct inode *inode = file_inode(file);
854 struct tty_struct *tty = file_tty(file);
855 struct tty_ldisc *ld;
857 if (tty_paranoia_check(tty, inode, "tty_read"))
859 if (!tty || tty_io_error(tty))
862 /* We want to wait for the line discipline to sort out in this
864 ld = tty_ldisc_ref_wait(tty);
866 return hung_up_tty_read(file, buf, count, ppos);
868 i = ld->ops->read(tty, file, buf, count);
874 tty_update_time(&inode->i_atime);
879 static void tty_write_unlock(struct tty_struct *tty)
881 mutex_unlock(&tty->atomic_write_lock);
882 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
885 static int tty_write_lock(struct tty_struct *tty, int ndelay)
887 if (!mutex_trylock(&tty->atomic_write_lock)) {
890 if (mutex_lock_interruptible(&tty->atomic_write_lock))
897 * Split writes up in sane blocksizes to avoid
898 * denial-of-service type attacks
900 static inline ssize_t do_tty_write(
901 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
902 struct tty_struct *tty,
904 const char __user *buf,
907 ssize_t ret, written = 0;
910 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
915 * We chunk up writes into a temporary buffer. This
916 * simplifies low-level drivers immensely, since they
917 * don't have locking issues and user mode accesses.
919 * But if TTY_NO_WRITE_SPLIT is set, we should use a
922 * The default chunk-size is 2kB, because the NTTY
923 * layer has problems with bigger chunks. It will
924 * claim to be able to handle more characters than
927 * FIXME: This can probably go away now except that 64K chunks
928 * are too likely to fail unless switched to vmalloc...
931 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
936 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
937 if (tty->write_cnt < chunk) {
938 unsigned char *buf_chunk;
943 buf_chunk = kmalloc(chunk, GFP_KERNEL);
948 kfree(tty->write_buf);
949 tty->write_cnt = chunk;
950 tty->write_buf = buf_chunk;
953 /* Do the write .. */
959 if (copy_from_user(tty->write_buf, buf, size))
961 ret = write(tty, file, tty->write_buf, size);
970 if (signal_pending(current))
975 tty_update_time(&file_inode(file)->i_mtime);
979 tty_write_unlock(tty);
984 * tty_write_message - write a message to a certain tty, not just the console.
985 * @tty: the destination tty_struct
986 * @msg: the message to write
988 * This is used for messages that need to be redirected to a specific tty.
989 * We don't put it into the syslog queue right now maybe in the future if
992 * We must still hold the BTM and test the CLOSING flag for the moment.
995 void tty_write_message(struct tty_struct *tty, char *msg)
998 mutex_lock(&tty->atomic_write_lock);
1000 if (tty->ops->write && tty->count > 0)
1001 tty->ops->write(tty, msg, strlen(msg));
1003 tty_write_unlock(tty);
1010 * tty_write - write method for tty device file
1011 * @file: tty file pointer
1012 * @buf: user data to write
1013 * @count: bytes to write
1016 * Write data to a tty device via the line discipline.
1019 * Locks the line discipline as required
1020 * Writes to the tty driver are serialized by the atomic_write_lock
1021 * and are then processed in chunks to the device. The line discipline
1022 * write method will not be invoked in parallel for each device.
1025 static ssize_t tty_write(struct file *file, const char __user *buf,
1026 size_t count, loff_t *ppos)
1028 struct tty_struct *tty = file_tty(file);
1029 struct tty_ldisc *ld;
1032 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1034 if (!tty || !tty->ops->write || tty_io_error(tty))
1036 /* Short term debug to catch buggy drivers */
1037 if (tty->ops->write_room == NULL)
1038 tty_err(tty, "missing write_room method\n");
1039 ld = tty_ldisc_ref_wait(tty);
1041 return hung_up_tty_write(file, buf, count, ppos);
1042 if (!ld->ops->write)
1045 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1046 tty_ldisc_deref(ld);
1050 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1051 size_t count, loff_t *ppos)
1053 struct file *p = NULL;
1055 spin_lock(&redirect_lock);
1057 p = get_file(redirect);
1058 spin_unlock(&redirect_lock);
1062 res = vfs_write(p, buf, count, &p->f_pos);
1066 return tty_write(file, buf, count, ppos);
1070 * tty_send_xchar - send priority character
1072 * Send a high priority character to the tty even if stopped
1074 * Locking: none for xchar method, write ordering for write method.
1077 int tty_send_xchar(struct tty_struct *tty, char ch)
1079 int was_stopped = tty->stopped;
1081 if (tty->ops->send_xchar) {
1082 down_read(&tty->termios_rwsem);
1083 tty->ops->send_xchar(tty, ch);
1084 up_read(&tty->termios_rwsem);
1088 if (tty_write_lock(tty, 0) < 0)
1089 return -ERESTARTSYS;
1091 down_read(&tty->termios_rwsem);
1094 tty->ops->write(tty, &ch, 1);
1097 up_read(&tty->termios_rwsem);
1098 tty_write_unlock(tty);
1102 static char ptychar[] = "pqrstuvwxyzabcde";
1105 * pty_line_name - generate name for a pty
1106 * @driver: the tty driver in use
1107 * @index: the minor number
1108 * @p: output buffer of at least 6 bytes
1110 * Generate a name from a driver reference and write it to the output
1115 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1117 int i = index + driver->name_base;
1118 /* ->name is initialized to "ttyp", but "tty" is expected */
1119 sprintf(p, "%s%c%x",
1120 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1121 ptychar[i >> 4 & 0xf], i & 0xf);
1125 * tty_line_name - generate name for a tty
1126 * @driver: the tty driver in use
1127 * @index: the minor number
1128 * @p: output buffer of at least 7 bytes
1130 * Generate a name from a driver reference and write it to the output
1135 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1137 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1138 return sprintf(p, "%s", driver->name);
1140 return sprintf(p, "%s%d", driver->name,
1141 index + driver->name_base);
1145 * tty_driver_lookup_tty() - find an existing tty, if any
1146 * @driver: the driver for the tty
1147 * @idx: the minor number
1149 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1150 * driver lookup() method returns an error.
1152 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1154 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1155 struct file *file, int idx)
1157 struct tty_struct *tty;
1159 if (driver->ops->lookup)
1161 tty = ERR_PTR(-EIO);
1163 tty = driver->ops->lookup(driver, file, idx);
1165 tty = driver->ttys[idx];
1173 * tty_init_termios - helper for termios setup
1174 * @tty: the tty to set up
1176 * Initialise the termios structure for this tty. This runs under
1177 * the tty_mutex currently so we can be relaxed about ordering.
1180 void tty_init_termios(struct tty_struct *tty)
1182 struct ktermios *tp;
1183 int idx = tty->index;
1185 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1186 tty->termios = tty->driver->init_termios;
1188 /* Check for lazy saved data */
1189 tp = tty->driver->termios[idx];
1192 tty->termios.c_line = tty->driver->init_termios.c_line;
1194 tty->termios = tty->driver->init_termios;
1196 /* Compatibility until drivers always set this */
1197 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1198 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1200 EXPORT_SYMBOL_GPL(tty_init_termios);
1202 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1204 tty_init_termios(tty);
1205 tty_driver_kref_get(driver);
1207 driver->ttys[tty->index] = tty;
1210 EXPORT_SYMBOL_GPL(tty_standard_install);
1213 * tty_driver_install_tty() - install a tty entry in the driver
1214 * @driver: the driver for the tty
1217 * Install a tty object into the driver tables. The tty->index field
1218 * will be set by the time this is called. This method is responsible
1219 * for ensuring any need additional structures are allocated and
1222 * Locking: tty_mutex for now
1224 static int tty_driver_install_tty(struct tty_driver *driver,
1225 struct tty_struct *tty)
1227 return driver->ops->install ? driver->ops->install(driver, tty) :
1228 tty_standard_install(driver, tty);
1232 * tty_driver_remove_tty() - remove a tty from the driver tables
1233 * @driver: the driver for the tty
1234 * @idx: the minor number
1236 * Remvoe a tty object from the driver tables. The tty->index field
1237 * will be set by the time this is called.
1239 * Locking: tty_mutex for now
1241 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1243 if (driver->ops->remove)
1244 driver->ops->remove(driver, tty);
1246 driver->ttys[tty->index] = NULL;
1250 * tty_reopen() - fast re-open of an open tty
1251 * @tty - the tty to open
1253 * Return 0 on success, -errno on error.
1254 * Re-opens on master ptys are not allowed and return -EIO.
1256 * Locking: Caller must hold tty_lock
1258 static int tty_reopen(struct tty_struct *tty)
1260 struct tty_driver *driver = tty->driver;
1261 struct tty_ldisc *ld;
1264 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1265 driver->subtype == PTY_TYPE_MASTER)
1271 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1274 ld = tty_ldisc_ref_wait(tty);
1276 tty_ldisc_deref(ld);
1278 retval = tty_ldisc_lock(tty, 5 * HZ);
1283 retval = tty_ldisc_reinit(tty, tty->termios.c_line);
1284 tty_ldisc_unlock(tty);
1294 * tty_init_dev - initialise a tty device
1295 * @driver: tty driver we are opening a device on
1296 * @idx: device index
1297 * @ret_tty: returned tty structure
1299 * Prepare a tty device. This may not be a "new" clean device but
1300 * could also be an active device. The pty drivers require special
1301 * handling because of this.
1304 * The function is called under the tty_mutex, which
1305 * protects us from the tty struct or driver itself going away.
1307 * On exit the tty device has the line discipline attached and
1308 * a reference count of 1. If a pair was created for pty/tty use
1309 * and the other was a pty master then it too has a reference count of 1.
1311 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1312 * failed open. The new code protects the open with a mutex, so it's
1313 * really quite straightforward. The mutex locking can probably be
1314 * relaxed for the (most common) case of reopening a tty.
1317 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1319 struct tty_struct *tty;
1323 * First time open is complex, especially for PTY devices.
1324 * This code guarantees that either everything succeeds and the
1325 * TTY is ready for operation, or else the table slots are vacated
1326 * and the allocated memory released. (Except that the termios
1330 if (!try_module_get(driver->owner))
1331 return ERR_PTR(-ENODEV);
1333 tty = alloc_tty_struct(driver, idx);
1336 goto err_module_put;
1340 retval = tty_driver_install_tty(driver, tty);
1345 tty->port = driver->ports[idx];
1347 WARN_RATELIMIT(!tty->port,
1348 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1349 __func__, tty->driver->name);
1351 retval = tty_ldisc_lock(tty, 5 * HZ);
1353 goto err_release_lock;
1354 tty->port->itty = tty;
1357 * Structures all installed ... call the ldisc open routines.
1358 * If we fail here just call release_tty to clean up. No need
1359 * to decrement the use counts, as release_tty doesn't care.
1361 retval = tty_ldisc_setup(tty, tty->link);
1363 goto err_release_tty;
1364 tty_ldisc_unlock(tty);
1365 /* Return the tty locked so that it cannot vanish under the caller */
1370 free_tty_struct(tty);
1372 module_put(driver->owner);
1373 return ERR_PTR(retval);
1375 /* call the tty release_tty routine to clean out this slot */
1377 tty_ldisc_unlock(tty);
1378 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1382 release_tty(tty, idx);
1383 return ERR_PTR(retval);
1387 * tty_save_termios() - save tty termios data in driver table
1388 * @tty: tty whose termios data to save
1390 * Locking: Caller guarantees serialisation with tty_init_termios().
1392 void tty_save_termios(struct tty_struct *tty)
1394 struct ktermios *tp;
1395 int idx = tty->index;
1397 /* If the port is going to reset then it has no termios to save */
1398 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1401 /* Stash the termios data */
1402 tp = tty->driver->termios[idx];
1404 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1407 tty->driver->termios[idx] = tp;
1411 EXPORT_SYMBOL_GPL(tty_save_termios);
1414 * tty_flush_works - flush all works of a tty/pty pair
1415 * @tty: tty device to flush works for (or either end of a pty pair)
1417 * Sync flush all works belonging to @tty (and the 'other' tty).
1419 static void tty_flush_works(struct tty_struct *tty)
1421 flush_work(&tty->SAK_work);
1422 flush_work(&tty->hangup_work);
1424 flush_work(&tty->link->SAK_work);
1425 flush_work(&tty->link->hangup_work);
1430 * release_one_tty - release tty structure memory
1431 * @kref: kref of tty we are obliterating
1433 * Releases memory associated with a tty structure, and clears out the
1434 * driver table slots. This function is called when a device is no longer
1435 * in use. It also gets called when setup of a device fails.
1438 * takes the file list lock internally when working on the list
1439 * of ttys that the driver keeps.
1441 * This method gets called from a work queue so that the driver private
1442 * cleanup ops can sleep (needed for USB at least)
1444 static void release_one_tty(struct work_struct *work)
1446 struct tty_struct *tty =
1447 container_of(work, struct tty_struct, hangup_work);
1448 struct tty_driver *driver = tty->driver;
1449 struct module *owner = driver->owner;
1451 if (tty->ops->cleanup)
1452 tty->ops->cleanup(tty);
1455 tty_driver_kref_put(driver);
1458 spin_lock(&tty->files_lock);
1459 list_del_init(&tty->tty_files);
1460 spin_unlock(&tty->files_lock);
1463 put_pid(tty->session);
1464 free_tty_struct(tty);
1467 static void queue_release_one_tty(struct kref *kref)
1469 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1471 /* The hangup queue is now free so we can reuse it rather than
1472 waste a chunk of memory for each port */
1473 INIT_WORK(&tty->hangup_work, release_one_tty);
1474 schedule_work(&tty->hangup_work);
1478 * tty_kref_put - release a tty kref
1481 * Release a reference to a tty device and if need be let the kref
1482 * layer destruct the object for us
1485 void tty_kref_put(struct tty_struct *tty)
1488 kref_put(&tty->kref, queue_release_one_tty);
1490 EXPORT_SYMBOL(tty_kref_put);
1493 * release_tty - release tty structure memory
1495 * Release both @tty and a possible linked partner (think pty pair),
1496 * and decrement the refcount of the backing module.
1500 * takes the file list lock internally when working on the list
1501 * of ttys that the driver keeps.
1504 static void release_tty(struct tty_struct *tty, int idx)
1506 /* This should always be true but check for the moment */
1507 WARN_ON(tty->index != idx);
1508 WARN_ON(!mutex_is_locked(&tty_mutex));
1509 if (tty->ops->shutdown)
1510 tty->ops->shutdown(tty);
1511 tty_save_termios(tty);
1512 tty_driver_remove_tty(tty->driver, tty);
1513 tty->port->itty = NULL;
1515 tty->link->port->itty = NULL;
1516 tty_buffer_cancel_work(tty->port);
1518 tty_buffer_cancel_work(tty->link->port);
1520 tty_kref_put(tty->link);
1525 * tty_release_checks - check a tty before real release
1526 * @tty: tty to check
1527 * @o_tty: link of @tty (if any)
1528 * @idx: index of the tty
1530 * Performs some paranoid checking before true release of the @tty.
1531 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1533 static int tty_release_checks(struct tty_struct *tty, int idx)
1535 #ifdef TTY_PARANOIA_CHECK
1536 if (idx < 0 || idx >= tty->driver->num) {
1537 tty_debug(tty, "bad idx %d\n", idx);
1541 /* not much to check for devpts */
1542 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1545 if (tty != tty->driver->ttys[idx]) {
1546 tty_debug(tty, "bad driver table[%d] = %p\n",
1547 idx, tty->driver->ttys[idx]);
1550 if (tty->driver->other) {
1551 struct tty_struct *o_tty = tty->link;
1553 if (o_tty != tty->driver->other->ttys[idx]) {
1554 tty_debug(tty, "bad other table[%d] = %p\n",
1555 idx, tty->driver->other->ttys[idx]);
1558 if (o_tty->link != tty) {
1559 tty_debug(tty, "bad link = %p\n", o_tty->link);
1568 * tty_kclose - closes tty opened by tty_kopen
1571 * Performs the final steps to release and free a tty device. It is the
1572 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1573 * flag on tty->port.
1575 void tty_kclose(struct tty_struct *tty)
1578 * Ask the line discipline code to release its structures
1580 tty_ldisc_release(tty);
1582 /* Wait for pending work before tty destruction commmences */
1583 tty_flush_works(tty);
1585 tty_debug_hangup(tty, "freeing structure\n");
1587 * The release_tty function takes care of the details of clearing
1588 * the slots and preserving the termios structure. The tty_unlock_pair
1589 * should be safe as we keep a kref while the tty is locked (so the
1590 * unlock never unlocks a freed tty).
1592 mutex_lock(&tty_mutex);
1593 tty_port_set_kopened(tty->port, 0);
1594 release_tty(tty, tty->index);
1595 mutex_unlock(&tty_mutex);
1597 EXPORT_SYMBOL_GPL(tty_kclose);
1600 * tty_release_struct - release a tty struct
1602 * @idx: index of the tty
1604 * Performs the final steps to release and free a tty device. It is
1605 * roughly the reverse of tty_init_dev.
1607 void tty_release_struct(struct tty_struct *tty, int idx)
1610 * Ask the line discipline code to release its structures
1612 tty_ldisc_release(tty);
1614 /* Wait for pending work before tty destruction commmences */
1615 tty_flush_works(tty);
1617 tty_debug_hangup(tty, "freeing structure\n");
1619 * The release_tty function takes care of the details of clearing
1620 * the slots and preserving the termios structure. The tty_unlock_pair
1621 * should be safe as we keep a kref while the tty is locked (so the
1622 * unlock never unlocks a freed tty).
1624 mutex_lock(&tty_mutex);
1625 release_tty(tty, idx);
1626 mutex_unlock(&tty_mutex);
1628 EXPORT_SYMBOL_GPL(tty_release_struct);
1631 * tty_release - vfs callback for close
1632 * @inode: inode of tty
1633 * @filp: file pointer for handle to tty
1635 * Called the last time each file handle is closed that references
1636 * this tty. There may however be several such references.
1639 * Takes bkl. See tty_release_dev
1641 * Even releasing the tty structures is a tricky business.. We have
1642 * to be very careful that the structures are all released at the
1643 * same time, as interrupts might otherwise get the wrong pointers.
1645 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1646 * lead to double frees or releasing memory still in use.
1649 int tty_release(struct inode *inode, struct file *filp)
1651 struct tty_struct *tty = file_tty(filp);
1652 struct tty_struct *o_tty = NULL;
1653 int do_sleep, final;
1658 if (tty_paranoia_check(tty, inode, __func__))
1662 check_tty_count(tty, __func__);
1664 __tty_fasync(-1, filp, 0);
1667 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1668 tty->driver->subtype == PTY_TYPE_MASTER)
1671 if (tty_release_checks(tty, idx)) {
1676 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1678 if (tty->ops->close)
1679 tty->ops->close(tty, filp);
1681 /* If tty is pty master, lock the slave pty (stable lock order) */
1682 tty_lock_slave(o_tty);
1685 * Sanity check: if tty->count is going to zero, there shouldn't be
1686 * any waiters on tty->read_wait or tty->write_wait. We test the
1687 * wait queues and kick everyone out _before_ actually starting to
1688 * close. This ensures that we won't block while releasing the tty
1691 * The test for the o_tty closing is necessary, since the master and
1692 * slave sides may close in any order. If the slave side closes out
1693 * first, its count will be one, since the master side holds an open.
1694 * Thus this test wouldn't be triggered at the time the slave closed,
1700 if (tty->count <= 1) {
1701 if (waitqueue_active(&tty->read_wait)) {
1702 wake_up_poll(&tty->read_wait, EPOLLIN);
1705 if (waitqueue_active(&tty->write_wait)) {
1706 wake_up_poll(&tty->write_wait, EPOLLOUT);
1710 if (o_tty && o_tty->count <= 1) {
1711 if (waitqueue_active(&o_tty->read_wait)) {
1712 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1715 if (waitqueue_active(&o_tty->write_wait)) {
1716 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1725 tty_warn(tty, "read/write wait queue active!\n");
1727 schedule_timeout_killable(timeout);
1728 if (timeout < 120 * HZ)
1729 timeout = 2 * timeout + 1;
1731 timeout = MAX_SCHEDULE_TIMEOUT;
1735 if (--o_tty->count < 0) {
1736 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1740 if (--tty->count < 0) {
1741 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1746 * We've decremented tty->count, so we need to remove this file
1747 * descriptor off the tty->tty_files list; this serves two
1749 * - check_tty_count sees the correct number of file descriptors
1750 * associated with this tty.
1751 * - do_tty_hangup no longer sees this file descriptor as
1752 * something that needs to be handled for hangups.
1757 * Perform some housekeeping before deciding whether to return.
1759 * If _either_ side is closing, make sure there aren't any
1760 * processes that still think tty or o_tty is their controlling
1764 read_lock(&tasklist_lock);
1765 session_clear_tty(tty->session);
1767 session_clear_tty(o_tty->session);
1768 read_unlock(&tasklist_lock);
1771 /* check whether both sides are closing ... */
1772 final = !tty->count && !(o_tty && o_tty->count);
1774 tty_unlock_slave(o_tty);
1777 /* At this point, the tty->count == 0 should ensure a dead tty
1778 cannot be re-opened by a racing opener */
1783 tty_debug_hangup(tty, "final close\n");
1785 tty_release_struct(tty, idx);
1790 * tty_open_current_tty - get locked tty of current task
1791 * @device: device number
1792 * @filp: file pointer to tty
1793 * @return: locked tty of the current task iff @device is /dev/tty
1795 * Performs a re-open of the current task's controlling tty.
1797 * We cannot return driver and index like for the other nodes because
1798 * devpts will not work then. It expects inodes to be from devpts FS.
1800 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1802 struct tty_struct *tty;
1805 if (device != MKDEV(TTYAUX_MAJOR, 0))
1808 tty = get_current_tty();
1810 return ERR_PTR(-ENXIO);
1812 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1815 tty_kref_put(tty); /* safe to drop the kref now */
1817 retval = tty_reopen(tty);
1820 tty = ERR_PTR(retval);
1826 * tty_lookup_driver - lookup a tty driver for a given device file
1827 * @device: device number
1828 * @filp: file pointer to tty
1829 * @index: index for the device in the @return driver
1830 * @return: driver for this inode (with increased refcount)
1832 * If @return is not erroneous, the caller is responsible to decrement the
1833 * refcount by tty_driver_kref_put.
1835 * Locking: tty_mutex protects get_tty_driver
1837 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1840 struct tty_driver *driver = NULL;
1844 case MKDEV(TTY_MAJOR, 0): {
1845 extern struct tty_driver *console_driver;
1846 driver = tty_driver_kref_get(console_driver);
1847 *index = fg_console;
1851 case MKDEV(TTYAUX_MAJOR, 1): {
1852 struct tty_driver *console_driver = console_device(index);
1853 if (console_driver) {
1854 driver = tty_driver_kref_get(console_driver);
1855 if (driver && filp) {
1856 /* Don't let /dev/console block */
1857 filp->f_flags |= O_NONBLOCK;
1862 tty_driver_kref_put(driver);
1863 return ERR_PTR(-ENODEV);
1866 driver = get_tty_driver(device, index);
1868 return ERR_PTR(-ENODEV);
1875 * tty_kopen - open a tty device for kernel
1876 * @device: dev_t of device to open
1878 * Opens tty exclusively for kernel. Performs the driver lookup,
1879 * makes sure it's not already opened and performs the first-time
1880 * tty initialization.
1882 * Returns the locked initialized &tty_struct
1884 * Claims the global tty_mutex to serialize:
1885 * - concurrent first-time tty initialization
1886 * - concurrent tty driver removal w/ lookup
1887 * - concurrent tty removal from driver table
1889 struct tty_struct *tty_kopen(dev_t device)
1891 struct tty_struct *tty;
1892 struct tty_driver *driver = NULL;
1895 mutex_lock(&tty_mutex);
1896 driver = tty_lookup_driver(device, NULL, &index);
1897 if (IS_ERR(driver)) {
1898 mutex_unlock(&tty_mutex);
1899 return ERR_CAST(driver);
1902 /* check whether we're reopening an existing tty */
1903 tty = tty_driver_lookup_tty(driver, NULL, index);
1908 /* drop kref from tty_driver_lookup_tty() */
1910 tty = ERR_PTR(-EBUSY);
1911 } else { /* tty_init_dev returns tty with the tty_lock held */
1912 tty = tty_init_dev(driver, index);
1915 tty_port_set_kopened(tty->port, 1);
1918 mutex_unlock(&tty_mutex);
1919 tty_driver_kref_put(driver);
1922 EXPORT_SYMBOL_GPL(tty_kopen);
1925 * tty_open_by_driver - open a tty device
1926 * @device: dev_t of device to open
1927 * @filp: file pointer to tty
1929 * Performs the driver lookup, checks for a reopen, or otherwise
1930 * performs the first-time tty initialization.
1932 * Returns the locked initialized or re-opened &tty_struct
1934 * Claims the global tty_mutex to serialize:
1935 * - concurrent first-time tty initialization
1936 * - concurrent tty driver removal w/ lookup
1937 * - concurrent tty removal from driver table
1939 static struct tty_struct *tty_open_by_driver(dev_t device,
1942 struct tty_struct *tty;
1943 struct tty_driver *driver = NULL;
1947 mutex_lock(&tty_mutex);
1948 driver = tty_lookup_driver(device, filp, &index);
1949 if (IS_ERR(driver)) {
1950 mutex_unlock(&tty_mutex);
1951 return ERR_CAST(driver);
1954 /* check whether we're reopening an existing tty */
1955 tty = tty_driver_lookup_tty(driver, filp, index);
1957 mutex_unlock(&tty_mutex);
1962 if (tty_port_kopened(tty->port)) {
1964 mutex_unlock(&tty_mutex);
1965 tty = ERR_PTR(-EBUSY);
1968 mutex_unlock(&tty_mutex);
1969 retval = tty_lock_interruptible(tty);
1970 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
1972 if (retval == -EINTR)
1973 retval = -ERESTARTSYS;
1974 tty = ERR_PTR(retval);
1977 retval = tty_reopen(tty);
1980 tty = ERR_PTR(retval);
1982 } else { /* Returns with the tty_lock held for now */
1983 tty = tty_init_dev(driver, index);
1984 mutex_unlock(&tty_mutex);
1987 tty_driver_kref_put(driver);
1992 * tty_open - open a tty device
1993 * @inode: inode of device file
1994 * @filp: file pointer to tty
1996 * tty_open and tty_release keep up the tty count that contains the
1997 * number of opens done on a tty. We cannot use the inode-count, as
1998 * different inodes might point to the same tty.
2000 * Open-counting is needed for pty masters, as well as for keeping
2001 * track of serial lines: DTR is dropped when the last close happens.
2002 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2004 * The termios state of a pty is reset on first open so that
2005 * settings don't persist across reuse.
2007 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2008 * tty->count should protect the rest.
2009 * ->siglock protects ->signal/->sighand
2011 * Note: the tty_unlock/lock cases without a ref are only safe due to
2015 static int tty_open(struct inode *inode, struct file *filp)
2017 struct tty_struct *tty;
2019 dev_t device = inode->i_rdev;
2020 unsigned saved_flags = filp->f_flags;
2022 nonseekable_open(inode, filp);
2025 retval = tty_alloc_file(filp);
2029 tty = tty_open_current_tty(device, filp);
2031 tty = tty_open_by_driver(device, filp);
2034 tty_free_file(filp);
2035 retval = PTR_ERR(tty);
2036 if (retval != -EAGAIN || signal_pending(current))
2042 tty_add_file(tty, filp);
2044 check_tty_count(tty, __func__);
2045 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2048 retval = tty->ops->open(tty, filp);
2051 filp->f_flags = saved_flags;
2054 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2056 tty_unlock(tty); /* need to call tty_release without BTM */
2057 tty_release(inode, filp);
2058 if (retval != -ERESTARTSYS)
2061 if (signal_pending(current))
2066 * Need to reset f_op in case a hangup happened.
2068 if (tty_hung_up_p(filp))
2069 filp->f_op = &tty_fops;
2072 clear_bit(TTY_HUPPED, &tty->flags);
2074 noctty = (filp->f_flags & O_NOCTTY) ||
2075 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2076 device == MKDEV(TTYAUX_MAJOR, 1) ||
2077 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2078 tty->driver->subtype == PTY_TYPE_MASTER);
2080 tty_open_proc_set_tty(filp, tty);
2088 * tty_poll - check tty status
2089 * @filp: file being polled
2090 * @wait: poll wait structures to update
2092 * Call the line discipline polling method to obtain the poll
2093 * status of the device.
2095 * Locking: locks called line discipline but ldisc poll method
2096 * may be re-entered freely by other callers.
2099 static __poll_t tty_poll(struct file *filp, poll_table *wait)
2101 struct tty_struct *tty = file_tty(filp);
2102 struct tty_ldisc *ld;
2105 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2108 ld = tty_ldisc_ref_wait(tty);
2110 return hung_up_tty_poll(filp, wait);
2112 ret = ld->ops->poll(tty, filp, wait);
2113 tty_ldisc_deref(ld);
2117 static int __tty_fasync(int fd, struct file *filp, int on)
2119 struct tty_struct *tty = file_tty(filp);
2120 unsigned long flags;
2123 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2126 retval = fasync_helper(fd, filp, on, &tty->fasync);
2134 spin_lock_irqsave(&tty->ctrl_lock, flags);
2137 type = PIDTYPE_PGID;
2139 pid = task_pid(current);
2140 type = PIDTYPE_TGID;
2143 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2144 __f_setown(filp, pid, type, 0);
2152 static int tty_fasync(int fd, struct file *filp, int on)
2154 struct tty_struct *tty = file_tty(filp);
2155 int retval = -ENOTTY;
2158 if (!tty_hung_up_p(filp))
2159 retval = __tty_fasync(fd, filp, on);
2166 * tiocsti - fake input character
2167 * @tty: tty to fake input into
2168 * @p: pointer to character
2170 * Fake input to a tty device. Does the necessary locking and
2173 * FIXME: does not honour flow control ??
2176 * Called functions take tty_ldiscs_lock
2177 * current->signal->tty check is safe without locks
2179 * FIXME: may race normal receive processing
2182 static int tiocsti(struct tty_struct *tty, char __user *p)
2185 struct tty_ldisc *ld;
2187 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2189 if (get_user(ch, p))
2191 tty_audit_tiocsti(tty, ch);
2192 ld = tty_ldisc_ref_wait(tty);
2195 if (ld->ops->receive_buf)
2196 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2197 tty_ldisc_deref(ld);
2202 * tiocgwinsz - implement window query ioctl
2204 * @arg: user buffer for result
2206 * Copies the kernel idea of the window size into the user buffer.
2208 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2212 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2216 mutex_lock(&tty->winsize_mutex);
2217 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2218 mutex_unlock(&tty->winsize_mutex);
2220 return err ? -EFAULT: 0;
2224 * tty_do_resize - resize event
2225 * @tty: tty being resized
2226 * @rows: rows (character)
2227 * @cols: cols (character)
2229 * Update the termios variables and send the necessary signals to
2230 * peform a terminal resize correctly
2233 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2238 mutex_lock(&tty->winsize_mutex);
2239 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2242 /* Signal the foreground process group */
2243 pgrp = tty_get_pgrp(tty);
2245 kill_pgrp(pgrp, SIGWINCH, 1);
2250 mutex_unlock(&tty->winsize_mutex);
2253 EXPORT_SYMBOL(tty_do_resize);
2256 * tiocswinsz - implement window size set ioctl
2257 * @tty; tty side of tty
2258 * @arg: user buffer for result
2260 * Copies the user idea of the window size to the kernel. Traditionally
2261 * this is just advisory information but for the Linux console it
2262 * actually has driver level meaning and triggers a VC resize.
2265 * Driver dependent. The default do_resize method takes the
2266 * tty termios mutex and ctrl_lock. The console takes its own lock
2267 * then calls into the default method.
2270 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2272 struct winsize tmp_ws;
2273 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2276 if (tty->ops->resize)
2277 return tty->ops->resize(tty, &tmp_ws);
2279 return tty_do_resize(tty, &tmp_ws);
2283 * tioccons - allow admin to move logical console
2284 * @file: the file to become console
2286 * Allow the administrator to move the redirected console device
2288 * Locking: uses redirect_lock to guard the redirect information
2291 static int tioccons(struct file *file)
2293 if (!capable(CAP_SYS_ADMIN))
2295 if (file->f_op->write == redirected_tty_write) {
2297 spin_lock(&redirect_lock);
2300 spin_unlock(&redirect_lock);
2305 spin_lock(&redirect_lock);
2307 spin_unlock(&redirect_lock);
2310 redirect = get_file(file);
2311 spin_unlock(&redirect_lock);
2316 * tiocsetd - set line discipline
2318 * @p: pointer to user data
2320 * Set the line discipline according to user request.
2322 * Locking: see tty_set_ldisc, this function is just a helper
2325 static int tiocsetd(struct tty_struct *tty, int __user *p)
2330 if (get_user(disc, p))
2333 ret = tty_set_ldisc(tty, disc);
2339 * tiocgetd - get line discipline
2341 * @p: pointer to user data
2343 * Retrieves the line discipline id directly from the ldisc.
2345 * Locking: waits for ldisc reference (in case the line discipline
2346 * is changing or the tty is being hungup)
2349 static int tiocgetd(struct tty_struct *tty, int __user *p)
2351 struct tty_ldisc *ld;
2354 ld = tty_ldisc_ref_wait(tty);
2357 ret = put_user(ld->ops->num, p);
2358 tty_ldisc_deref(ld);
2363 * send_break - performed time break
2364 * @tty: device to break on
2365 * @duration: timeout in mS
2367 * Perform a timed break on hardware that lacks its own driver level
2368 * timed break functionality.
2371 * atomic_write_lock serializes
2375 static int send_break(struct tty_struct *tty, unsigned int duration)
2379 if (tty->ops->break_ctl == NULL)
2382 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2383 retval = tty->ops->break_ctl(tty, duration);
2385 /* Do the work ourselves */
2386 if (tty_write_lock(tty, 0) < 0)
2388 retval = tty->ops->break_ctl(tty, -1);
2391 if (!signal_pending(current))
2392 msleep_interruptible(duration);
2393 retval = tty->ops->break_ctl(tty, 0);
2395 tty_write_unlock(tty);
2396 if (signal_pending(current))
2403 * tty_tiocmget - get modem status
2405 * @file: user file pointer
2406 * @p: pointer to result
2408 * Obtain the modem status bits from the tty driver if the feature
2409 * is supported. Return -EINVAL if it is not available.
2411 * Locking: none (up to the driver)
2414 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2416 int retval = -EINVAL;
2418 if (tty->ops->tiocmget) {
2419 retval = tty->ops->tiocmget(tty);
2422 retval = put_user(retval, p);
2428 * tty_tiocmset - set modem status
2430 * @cmd: command - clear bits, set bits or set all
2431 * @p: pointer to desired bits
2433 * Set the modem status bits from the tty driver if the feature
2434 * is supported. Return -EINVAL if it is not available.
2436 * Locking: none (up to the driver)
2439 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2443 unsigned int set, clear, val;
2445 if (tty->ops->tiocmset == NULL)
2448 retval = get_user(val, p);
2464 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2465 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2466 return tty->ops->tiocmset(tty, set, clear);
2469 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2471 int retval = -EINVAL;
2472 struct serial_icounter_struct icount;
2473 memset(&icount, 0, sizeof(icount));
2474 if (tty->ops->get_icount)
2475 retval = tty->ops->get_icount(tty, &icount);
2478 if (copy_to_user(arg, &icount, sizeof(icount)))
2483 static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
2485 static DEFINE_RATELIMIT_STATE(depr_flags,
2486 DEFAULT_RATELIMIT_INTERVAL,
2487 DEFAULT_RATELIMIT_BURST);
2488 char comm[TASK_COMM_LEN];
2489 struct serial_struct v;
2492 if (copy_from_user(&v, ss, sizeof(struct serial_struct)))
2495 flags = v.flags & ASYNC_DEPRECATED;
2497 if (flags && __ratelimit(&depr_flags))
2498 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2499 __func__, get_task_comm(comm, current), flags);
2500 if (!tty->ops->set_serial)
2502 return tty->ops->set_serial(tty, &v);
2505 static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
2507 struct serial_struct v;
2510 memset(&v, 0, sizeof(struct serial_struct));
2511 if (!tty->ops->get_serial)
2513 err = tty->ops->get_serial(tty, &v);
2514 if (!err && copy_to_user(ss, &v, sizeof(struct serial_struct)))
2520 * if pty, return the slave side (real_tty)
2521 * otherwise, return self
2523 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2525 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2526 tty->driver->subtype == PTY_TYPE_MASTER)
2532 * Split this up, as gcc can choke on it otherwise..
2534 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2536 struct tty_struct *tty = file_tty(file);
2537 struct tty_struct *real_tty;
2538 void __user *p = (void __user *)arg;
2540 struct tty_ldisc *ld;
2542 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2545 real_tty = tty_pair_get_tty(tty);
2548 * Factor out some common prep work
2556 retval = tty_check_change(tty);
2559 if (cmd != TIOCCBRK) {
2560 tty_wait_until_sent(tty, 0);
2561 if (signal_pending(current))
2572 return tiocsti(tty, p);
2574 return tiocgwinsz(real_tty, p);
2576 return tiocswinsz(real_tty, p);
2578 return real_tty != tty ? -EINVAL : tioccons(file);
2580 set_bit(TTY_EXCLUSIVE, &tty->flags);
2583 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2587 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2588 return put_user(excl, (int __user *)p);
2591 return tiocgetd(tty, p);
2593 return tiocsetd(tty, p);
2595 if (!capable(CAP_SYS_ADMIN))
2601 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2602 return put_user(ret, (unsigned int __user *)p);
2607 case TIOCSBRK: /* Turn break on, unconditionally */
2608 if (tty->ops->break_ctl)
2609 return tty->ops->break_ctl(tty, -1);
2611 case TIOCCBRK: /* Turn break off, unconditionally */
2612 if (tty->ops->break_ctl)
2613 return tty->ops->break_ctl(tty, 0);
2615 case TCSBRK: /* SVID version: non-zero arg --> no break */
2616 /* non-zero arg means wait for all output data
2617 * to be sent (performed above) but don't send break.
2618 * This is used by the tcdrain() termios function.
2621 return send_break(tty, 250);
2623 case TCSBRKP: /* support for POSIX tcsendbreak() */
2624 return send_break(tty, arg ? arg*100 : 250);
2627 return tty_tiocmget(tty, p);
2631 return tty_tiocmset(tty, cmd, p);
2633 return tty_tiocgicount(tty, p);
2638 /* flush tty buffer and allow ldisc to process ioctl */
2639 tty_buffer_flush(tty, NULL);
2644 return tty_tiocsserial(tty, p);
2646 return tty_tiocgserial(tty, p);
2648 /* Special because the struct file is needed */
2649 return ptm_open_peer(file, tty, (int)arg);
2651 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2652 if (retval != -ENOIOCTLCMD)
2655 if (tty->ops->ioctl) {
2656 retval = tty->ops->ioctl(tty, cmd, arg);
2657 if (retval != -ENOIOCTLCMD)
2660 ld = tty_ldisc_ref_wait(tty);
2662 return hung_up_tty_ioctl(file, cmd, arg);
2664 if (ld->ops->ioctl) {
2665 retval = ld->ops->ioctl(tty, file, cmd, arg);
2666 if (retval == -ENOIOCTLCMD)
2669 tty_ldisc_deref(ld);
2673 #ifdef CONFIG_COMPAT
2675 struct serial_struct32 {
2681 compat_int_t xmit_fifo_size;
2682 compat_int_t custom_divisor;
2683 compat_int_t baud_base;
2684 unsigned short close_delay;
2686 char reserved_char[1];
2688 unsigned short closing_wait; /* time to wait before closing */
2689 unsigned short closing_wait2; /* no longer used... */
2690 compat_uint_t iomem_base;
2691 unsigned short iomem_reg_shift;
2692 unsigned int port_high;
2693 /* compat_ulong_t iomap_base FIXME */
2694 compat_int_t reserved[1];
2697 static int compat_tty_tiocsserial(struct tty_struct *tty,
2698 struct serial_struct32 __user *ss)
2700 static DEFINE_RATELIMIT_STATE(depr_flags,
2701 DEFAULT_RATELIMIT_INTERVAL,
2702 DEFAULT_RATELIMIT_BURST);
2703 char comm[TASK_COMM_LEN];
2704 struct serial_struct32 v32;
2705 struct serial_struct v;
2708 if (copy_from_user(&v32, ss, sizeof(struct serial_struct32)))
2711 memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base));
2712 v.iomem_base = compat_ptr(v32.iomem_base);
2713 v.iomem_reg_shift = v32.iomem_reg_shift;
2714 v.port_high = v32.port_high;
2717 flags = v.flags & ASYNC_DEPRECATED;
2719 if (flags && __ratelimit(&depr_flags))
2720 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2721 __func__, get_task_comm(comm, current), flags);
2722 if (!tty->ops->set_serial)
2724 return tty->ops->set_serial(tty, &v);
2727 static int compat_tty_tiocgserial(struct tty_struct *tty,
2728 struct serial_struct32 __user *ss)
2730 struct serial_struct32 v32;
2731 struct serial_struct v;
2733 memset(&v, 0, sizeof(struct serial_struct));
2735 if (!tty->ops->set_serial)
2737 err = tty->ops->get_serial(tty, &v);
2739 memcpy(&v32, &v, offsetof(struct serial_struct32, iomem_base));
2740 v32.iomem_base = (unsigned long)v.iomem_base >> 32 ?
2741 0xfffffff : ptr_to_compat(v.iomem_base);
2742 v32.iomem_reg_shift = v.iomem_reg_shift;
2743 v32.port_high = v.port_high;
2744 if (copy_to_user(ss, &v32, sizeof(struct serial_struct32)))
2749 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2752 struct tty_struct *tty = file_tty(file);
2753 struct tty_ldisc *ld;
2754 int retval = -ENOIOCTLCMD;
2802 case TIOCGLCKTRMIOS:
2803 case TIOCSLCKTRMIOS:
2812 return tty_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2828 return tty_ioctl(file, cmd, arg);
2831 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2836 return compat_tty_tiocsserial(tty, compat_ptr(arg));
2838 return compat_tty_tiocgserial(tty, compat_ptr(arg));
2840 if (tty->ops->compat_ioctl) {
2841 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2842 if (retval != -ENOIOCTLCMD)
2846 ld = tty_ldisc_ref_wait(tty);
2848 return hung_up_tty_compat_ioctl(file, cmd, arg);
2849 if (ld->ops->compat_ioctl)
2850 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2851 if (retval == -ENOIOCTLCMD && ld->ops->ioctl)
2852 retval = ld->ops->ioctl(tty, file,
2853 (unsigned long)compat_ptr(cmd), arg);
2854 tty_ldisc_deref(ld);
2860 static int this_tty(const void *t, struct file *file, unsigned fd)
2862 if (likely(file->f_op->read != tty_read))
2864 return file_tty(file) != t ? 0 : fd + 1;
2868 * This implements the "Secure Attention Key" --- the idea is to
2869 * prevent trojan horses by killing all processes associated with this
2870 * tty when the user hits the "Secure Attention Key". Required for
2871 * super-paranoid applications --- see the Orange Book for more details.
2873 * This code could be nicer; ideally it should send a HUP, wait a few
2874 * seconds, then send a INT, and then a KILL signal. But you then
2875 * have to coordinate with the init process, since all processes associated
2876 * with the current tty must be dead before the new getty is allowed
2879 * Now, if it would be correct ;-/ The current code has a nasty hole -
2880 * it doesn't catch files in flight. We may send the descriptor to ourselves
2881 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2883 * Nasty bug: do_SAK is being called in interrupt context. This can
2884 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2886 void __do_SAK(struct tty_struct *tty)
2891 struct task_struct *g, *p;
2892 struct pid *session;
2897 session = tty->session;
2899 tty_ldisc_flush(tty);
2901 tty_driver_flush_buffer(tty);
2903 read_lock(&tasklist_lock);
2904 /* Kill the entire session */
2905 do_each_pid_task(session, PIDTYPE_SID, p) {
2906 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
2907 task_pid_nr(p), p->comm);
2908 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
2909 } while_each_pid_task(session, PIDTYPE_SID, p);
2911 /* Now kill any processes that happen to have the tty open */
2912 do_each_thread(g, p) {
2913 if (p->signal->tty == tty) {
2914 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
2915 task_pid_nr(p), p->comm);
2916 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
2920 i = iterate_fd(p->files, 0, this_tty, tty);
2922 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
2923 task_pid_nr(p), p->comm, i - 1);
2924 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
2927 } while_each_thread(g, p);
2928 read_unlock(&tasklist_lock);
2932 static void do_SAK_work(struct work_struct *work)
2934 struct tty_struct *tty =
2935 container_of(work, struct tty_struct, SAK_work);
2940 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2941 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2942 * the values which we write to it will be identical to the values which it
2943 * already has. --akpm
2945 void do_SAK(struct tty_struct *tty)
2949 schedule_work(&tty->SAK_work);
2952 EXPORT_SYMBOL(do_SAK);
2954 /* Must put_device() after it's unused! */
2955 static struct device *tty_get_device(struct tty_struct *tty)
2957 dev_t devt = tty_devnum(tty);
2958 return class_find_device_by_devt(tty_class, devt);
2965 * This subroutine allocates and initializes a tty structure.
2967 * Locking: none - tty in question is not exposed at this point
2970 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
2972 struct tty_struct *tty;
2974 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
2978 kref_init(&tty->kref);
2979 tty->magic = TTY_MAGIC;
2980 if (tty_ldisc_init(tty)) {
2984 tty->session = NULL;
2986 mutex_init(&tty->legacy_mutex);
2987 mutex_init(&tty->throttle_mutex);
2988 init_rwsem(&tty->termios_rwsem);
2989 mutex_init(&tty->winsize_mutex);
2990 init_ldsem(&tty->ldisc_sem);
2991 init_waitqueue_head(&tty->write_wait);
2992 init_waitqueue_head(&tty->read_wait);
2993 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2994 mutex_init(&tty->atomic_write_lock);
2995 spin_lock_init(&tty->ctrl_lock);
2996 spin_lock_init(&tty->flow_lock);
2997 spin_lock_init(&tty->files_lock);
2998 INIT_LIST_HEAD(&tty->tty_files);
2999 INIT_WORK(&tty->SAK_work, do_SAK_work);
3001 tty->driver = driver;
3002 tty->ops = driver->ops;
3004 tty_line_name(driver, idx, tty->name);
3005 tty->dev = tty_get_device(tty);
3011 * tty_put_char - write one character to a tty
3015 * Write one byte to the tty using the provided put_char method
3016 * if present. Returns the number of characters successfully output.
3018 * Note: the specific put_char operation in the driver layer may go
3019 * away soon. Don't call it directly, use this method
3022 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3024 if (tty->ops->put_char)
3025 return tty->ops->put_char(tty, ch);
3026 return tty->ops->write(tty, &ch, 1);
3028 EXPORT_SYMBOL_GPL(tty_put_char);
3030 struct class *tty_class;
3032 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3033 unsigned int index, unsigned int count)
3037 /* init here, since reused cdevs cause crashes */
3038 driver->cdevs[index] = cdev_alloc();
3039 if (!driver->cdevs[index])
3041 driver->cdevs[index]->ops = &tty_fops;
3042 driver->cdevs[index]->owner = driver->owner;
3043 err = cdev_add(driver->cdevs[index], dev, count);
3045 kobject_put(&driver->cdevs[index]->kobj);
3050 * tty_register_device - register a tty device
3051 * @driver: the tty driver that describes the tty device
3052 * @index: the index in the tty driver for this tty device
3053 * @device: a struct device that is associated with this tty device.
3054 * This field is optional, if there is no known struct device
3055 * for this tty device it can be set to NULL safely.
3057 * Returns a pointer to the struct device for this tty device
3058 * (or ERR_PTR(-EFOO) on error).
3060 * This call is required to be made to register an individual tty device
3061 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3062 * that bit is not set, this function should not be called by a tty
3068 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3069 struct device *device)
3071 return tty_register_device_attr(driver, index, device, NULL, NULL);
3073 EXPORT_SYMBOL(tty_register_device);
3075 static void tty_device_create_release(struct device *dev)
3077 dev_dbg(dev, "releasing...\n");
3082 * tty_register_device_attr - register a tty device
3083 * @driver: the tty driver that describes the tty device
3084 * @index: the index in the tty driver for this tty device
3085 * @device: a struct device that is associated with this tty device.
3086 * This field is optional, if there is no known struct device
3087 * for this tty device it can be set to NULL safely.
3088 * @drvdata: Driver data to be set to device.
3089 * @attr_grp: Attribute group to be set on device.
3091 * Returns a pointer to the struct device for this tty device
3092 * (or ERR_PTR(-EFOO) on error).
3094 * This call is required to be made to register an individual tty device
3095 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3096 * that bit is not set, this function should not be called by a tty
3101 struct device *tty_register_device_attr(struct tty_driver *driver,
3102 unsigned index, struct device *device,
3104 const struct attribute_group **attr_grp)
3107 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3108 struct ktermios *tp;
3112 if (index >= driver->num) {
3113 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3114 driver->name, index);
3115 return ERR_PTR(-EINVAL);
3118 if (driver->type == TTY_DRIVER_TYPE_PTY)
3119 pty_line_name(driver, index, name);
3121 tty_line_name(driver, index, name);
3123 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3125 return ERR_PTR(-ENOMEM);
3128 dev->class = tty_class;
3129 dev->parent = device;
3130 dev->release = tty_device_create_release;
3131 dev_set_name(dev, "%s", name);
3132 dev->groups = attr_grp;
3133 dev_set_drvdata(dev, drvdata);
3135 dev_set_uevent_suppress(dev, 1);
3137 retval = device_register(dev);
3141 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3143 * Free any saved termios data so that the termios state is
3144 * reset when reusing a minor number.
3146 tp = driver->termios[index];
3148 driver->termios[index] = NULL;
3152 retval = tty_cdev_add(driver, devt, index, 1);
3157 dev_set_uevent_suppress(dev, 0);
3158 kobject_uevent(&dev->kobj, KOBJ_ADD);
3167 return ERR_PTR(retval);
3169 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3172 * tty_unregister_device - unregister a tty device
3173 * @driver: the tty driver that describes the tty device
3174 * @index: the index in the tty driver for this tty device
3176 * If a tty device is registered with a call to tty_register_device() then
3177 * this function must be called when the tty device is gone.
3182 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3184 device_destroy(tty_class,
3185 MKDEV(driver->major, driver->minor_start) + index);
3186 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3187 cdev_del(driver->cdevs[index]);
3188 driver->cdevs[index] = NULL;
3191 EXPORT_SYMBOL(tty_unregister_device);
3194 * __tty_alloc_driver -- allocate tty driver
3195 * @lines: count of lines this driver can handle at most
3196 * @owner: module which is responsible for this driver
3197 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3199 * This should not be called directly, some of the provided macros should be
3200 * used instead. Use IS_ERR and friends on @retval.
3202 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3203 unsigned long flags)
3205 struct tty_driver *driver;
3206 unsigned int cdevs = 1;
3209 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3210 return ERR_PTR(-EINVAL);
3212 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3214 return ERR_PTR(-ENOMEM);
3216 kref_init(&driver->kref);
3217 driver->magic = TTY_DRIVER_MAGIC;
3218 driver->num = lines;
3219 driver->owner = owner;
3220 driver->flags = flags;
3222 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3223 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3225 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3227 if (!driver->ttys || !driver->termios) {
3233 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3234 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3236 if (!driver->ports) {
3243 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3244 if (!driver->cdevs) {
3251 kfree(driver->ports);
3252 kfree(driver->ttys);
3253 kfree(driver->termios);
3254 kfree(driver->cdevs);
3256 return ERR_PTR(err);
3258 EXPORT_SYMBOL(__tty_alloc_driver);
3260 static void destruct_tty_driver(struct kref *kref)
3262 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3264 struct ktermios *tp;
3266 if (driver->flags & TTY_DRIVER_INSTALLED) {
3267 for (i = 0; i < driver->num; i++) {
3268 tp = driver->termios[i];
3270 driver->termios[i] = NULL;
3273 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3274 tty_unregister_device(driver, i);
3276 proc_tty_unregister_driver(driver);
3277 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3278 cdev_del(driver->cdevs[0]);
3280 kfree(driver->cdevs);
3281 kfree(driver->ports);
3282 kfree(driver->termios);
3283 kfree(driver->ttys);
3287 void tty_driver_kref_put(struct tty_driver *driver)
3289 kref_put(&driver->kref, destruct_tty_driver);
3291 EXPORT_SYMBOL(tty_driver_kref_put);
3293 void tty_set_operations(struct tty_driver *driver,
3294 const struct tty_operations *op)
3298 EXPORT_SYMBOL(tty_set_operations);
3300 void put_tty_driver(struct tty_driver *d)
3302 tty_driver_kref_put(d);
3304 EXPORT_SYMBOL(put_tty_driver);
3307 * Called by a tty driver to register itself.
3309 int tty_register_driver(struct tty_driver *driver)
3316 if (!driver->major) {
3317 error = alloc_chrdev_region(&dev, driver->minor_start,
3318 driver->num, driver->name);
3320 driver->major = MAJOR(dev);
3321 driver->minor_start = MINOR(dev);
3324 dev = MKDEV(driver->major, driver->minor_start);
3325 error = register_chrdev_region(dev, driver->num, driver->name);
3330 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3331 error = tty_cdev_add(driver, dev, 0, driver->num);
3333 goto err_unreg_char;
3336 mutex_lock(&tty_mutex);
3337 list_add(&driver->tty_drivers, &tty_drivers);
3338 mutex_unlock(&tty_mutex);
3340 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3341 for (i = 0; i < driver->num; i++) {
3342 d = tty_register_device(driver, i, NULL);
3345 goto err_unreg_devs;
3349 proc_tty_register_driver(driver);
3350 driver->flags |= TTY_DRIVER_INSTALLED;
3354 for (i--; i >= 0; i--)
3355 tty_unregister_device(driver, i);
3357 mutex_lock(&tty_mutex);
3358 list_del(&driver->tty_drivers);
3359 mutex_unlock(&tty_mutex);
3362 unregister_chrdev_region(dev, driver->num);
3366 EXPORT_SYMBOL(tty_register_driver);
3369 * Called by a tty driver to unregister itself.
3371 int tty_unregister_driver(struct tty_driver *driver)
3375 if (driver->refcount)
3378 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3380 mutex_lock(&tty_mutex);
3381 list_del(&driver->tty_drivers);
3382 mutex_unlock(&tty_mutex);
3386 EXPORT_SYMBOL(tty_unregister_driver);
3388 dev_t tty_devnum(struct tty_struct *tty)
3390 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3392 EXPORT_SYMBOL(tty_devnum);
3394 void tty_default_fops(struct file_operations *fops)
3399 static char *tty_devnode(struct device *dev, umode_t *mode)
3403 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3404 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3409 static int __init tty_class_init(void)
3411 tty_class = class_create(THIS_MODULE, "tty");
3412 if (IS_ERR(tty_class))
3413 return PTR_ERR(tty_class);
3414 tty_class->devnode = tty_devnode;
3418 postcore_initcall(tty_class_init);
3420 /* 3/2004 jmc: why do these devices exist? */
3421 static struct cdev tty_cdev, console_cdev;
3423 static ssize_t show_cons_active(struct device *dev,
3424 struct device_attribute *attr, char *buf)
3426 struct console *cs[16];
3432 for_each_console(c) {
3437 if ((c->flags & CON_ENABLED) == 0)
3440 if (i >= ARRAY_SIZE(cs))
3444 int index = cs[i]->index;
3445 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3447 /* don't resolve tty0 as some programs depend on it */
3448 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3449 count += tty_line_name(drv, index, buf + count);
3451 count += sprintf(buf + count, "%s%d",
3452 cs[i]->name, cs[i]->index);
3454 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3460 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3462 static struct attribute *cons_dev_attrs[] = {
3463 &dev_attr_active.attr,
3467 ATTRIBUTE_GROUPS(cons_dev);
3469 static struct device *consdev;
3471 void console_sysfs_notify(void)
3474 sysfs_notify(&consdev->kobj, NULL, "active");
3478 * Ok, now we can initialize the rest of the tty devices and can count
3479 * on memory allocations, interrupts etc..
3481 int __init tty_init(void)
3484 cdev_init(&tty_cdev, &tty_fops);
3485 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3486 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3487 panic("Couldn't register /dev/tty driver\n");
3488 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3490 cdev_init(&console_cdev, &console_fops);
3491 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3492 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3493 panic("Couldn't register /dev/console driver\n");
3494 consdev = device_create_with_groups(tty_class, NULL,
3495 MKDEV(TTYAUX_MAJOR, 1), NULL,
3496 cons_dev_groups, "console");
3497 if (IS_ERR(consdev))
3501 vty_init(&console_fops);