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/ppp-ioctl.h>
91 #include <linux/proc_fs.h>
92 #include <linux/init.h>
93 #include <linux/module.h>
94 #include <linux/device.h>
95 #include <linux/wait.h>
96 #include <linux/bitops.h>
97 #include <linux/delay.h>
98 #include <linux/seq_file.h>
99 #include <linux/serial.h>
100 #include <linux/ratelimit.h>
101 #include <linux/compat.h>
103 #include <linux/uaccess.h>
105 #include <linux/kbd_kern.h>
106 #include <linux/vt_kern.h>
107 #include <linux/selection.h>
109 #include <linux/kmod.h>
110 #include <linux/nsproxy.h>
112 #undef TTY_DEBUG_HANGUP
113 #ifdef TTY_DEBUG_HANGUP
114 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
116 # define tty_debug_hangup(tty, f, args...) do { } while (0)
119 #define TTY_PARANOIA_CHECK 1
120 #define CHECK_TTY_COUNT 1
122 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
123 .c_iflag = ICRNL | IXON,
124 .c_oflag = OPOST | ONLCR,
125 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
126 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
127 ECHOCTL | ECHOKE | IEXTEN,
131 /* .c_line = N_TTY, */
134 EXPORT_SYMBOL(tty_std_termios);
136 /* This list gets poked at by procfs and various bits of boot up code. This
137 could do with some rationalisation such as pulling the tty proc function
140 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
142 /* Mutex to protect creating and releasing a tty */
143 DEFINE_MUTEX(tty_mutex);
145 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
146 static ssize_t tty_write(struct kiocb *, struct iov_iter *);
147 static __poll_t tty_poll(struct file *, poll_table *);
148 static int tty_open(struct inode *, struct file *);
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
283 int count = 0, kopen_count = 0;
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_port_kopened(tty->port))
296 if (tty->count != (count + kopen_count)) {
297 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
298 routine, tty->count, count, kopen_count);
299 return (count + kopen_count);
306 * get_tty_driver - find device of a tty
307 * @device: device identifier
308 * @index: returns the index of the tty
310 * This routine returns a tty driver structure, given a device number
311 * and also passes back the index number.
313 * Locking: caller must hold tty_mutex
316 static struct tty_driver *get_tty_driver(dev_t device, int *index)
318 struct tty_driver *p;
320 list_for_each_entry(p, &tty_drivers, tty_drivers) {
321 dev_t base = MKDEV(p->major, p->minor_start);
322 if (device < base || device >= base + p->num)
324 *index = device - base;
325 return tty_driver_kref_get(p);
331 * tty_dev_name_to_number - return dev_t for device name
332 * @name: user space name of device under /dev
333 * @number: pointer to dev_t that this function will populate
335 * This function converts device names like ttyS0 or ttyUSB1 into dev_t
336 * like (4, 64) or (188, 1). If no corresponding driver is registered then
337 * the function returns -ENODEV.
339 * Locking: this acquires tty_mutex to protect the tty_drivers list from
340 * being modified while we are traversing it, and makes sure to
341 * release it before exiting.
343 int tty_dev_name_to_number(const char *name, dev_t *number)
345 struct tty_driver *p;
347 int index, prefix_length = 0;
350 for (str = name; *str && !isdigit(*str); str++)
356 ret = kstrtoint(str, 10, &index);
360 prefix_length = str - name;
361 mutex_lock(&tty_mutex);
363 list_for_each_entry(p, &tty_drivers, tty_drivers)
364 if (prefix_length == strlen(p->name) && strncmp(name,
365 p->name, prefix_length) == 0) {
366 if (index < p->num) {
367 *number = MKDEV(p->major, p->minor_start + index);
372 /* if here then driver wasn't found */
375 mutex_unlock(&tty_mutex);
378 EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
380 #ifdef CONFIG_CONSOLE_POLL
383 * tty_find_polling_driver - find device of a polled tty
384 * @name: name string to match
385 * @line: pointer to resulting tty line nr
387 * This routine returns a tty driver structure, given a name
388 * and the condition that the tty driver is capable of polled
391 struct tty_driver *tty_find_polling_driver(char *name, int *line)
393 struct tty_driver *p, *res = NULL;
398 for (str = name; *str; str++)
399 if ((*str >= '0' && *str <= '9') || *str == ',')
405 tty_line = simple_strtoul(str, &str, 10);
407 mutex_lock(&tty_mutex);
408 /* Search through the tty devices to look for a match */
409 list_for_each_entry(p, &tty_drivers, tty_drivers) {
410 if (!len || strncmp(name, p->name, len) != 0)
418 if (tty_line >= 0 && tty_line < p->num && p->ops &&
419 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
420 res = tty_driver_kref_get(p);
425 mutex_unlock(&tty_mutex);
429 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
432 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
433 size_t count, loff_t *ppos)
438 static ssize_t hung_up_tty_write(struct kiocb *iocb, struct iov_iter *from)
443 /* No kernel lock held - none needed ;) */
444 static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
446 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
449 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
452 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
455 static long hung_up_tty_compat_ioctl(struct file *file,
456 unsigned int cmd, unsigned long arg)
458 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
461 static int hung_up_tty_fasync(int fd, struct file *file, int on)
466 static void tty_show_fdinfo(struct seq_file *m, struct file *file)
468 struct tty_struct *tty = file_tty(file);
470 if (tty && tty->ops && tty->ops->show_fdinfo)
471 tty->ops->show_fdinfo(tty, m);
474 static const struct file_operations tty_fops = {
477 .write_iter = tty_write,
478 .splice_write = iter_file_splice_write,
480 .unlocked_ioctl = tty_ioctl,
481 .compat_ioctl = tty_compat_ioctl,
483 .release = tty_release,
484 .fasync = tty_fasync,
485 .show_fdinfo = tty_show_fdinfo,
488 static const struct file_operations console_fops = {
491 .write_iter = redirected_tty_write,
492 .splice_write = iter_file_splice_write,
494 .unlocked_ioctl = tty_ioctl,
495 .compat_ioctl = tty_compat_ioctl,
497 .release = tty_release,
498 .fasync = tty_fasync,
501 static const struct file_operations hung_up_tty_fops = {
503 .read = hung_up_tty_read,
504 .write_iter = hung_up_tty_write,
505 .poll = hung_up_tty_poll,
506 .unlocked_ioctl = hung_up_tty_ioctl,
507 .compat_ioctl = hung_up_tty_compat_ioctl,
508 .release = tty_release,
509 .fasync = hung_up_tty_fasync,
512 static DEFINE_SPINLOCK(redirect_lock);
513 static struct file *redirect;
516 * tty_wakeup - request more data
519 * Internal and external helper for wakeups of tty. This function
520 * informs the line discipline if present that the driver is ready
521 * to receive more output data.
524 void tty_wakeup(struct tty_struct *tty)
526 struct tty_ldisc *ld;
528 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
529 ld = tty_ldisc_ref(tty);
531 if (ld->ops->write_wakeup)
532 ld->ops->write_wakeup(tty);
536 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
539 EXPORT_SYMBOL_GPL(tty_wakeup);
542 * __tty_hangup - actual handler for hangup events
544 * @exit_session: if non-zero, signal all foreground group processes
546 * This can be called by a "kworker" kernel thread. That is process
547 * synchronous but doesn't hold any locks, so we need to make sure we
548 * have the appropriate locks for what we're doing.
550 * The hangup event clears any pending redirections onto the hung up
551 * device. It ensures future writes will error and it does the needed
552 * line discipline hangup and signal delivery. The tty object itself
557 * redirect lock for undoing redirection
558 * file list lock for manipulating list of ttys
559 * tty_ldiscs_lock from called functions
560 * termios_rwsem resetting termios data
561 * tasklist_lock to walk task list for hangup event
562 * ->siglock to protect ->signal/->sighand
564 static void __tty_hangup(struct tty_struct *tty, int exit_session)
566 struct file *cons_filp = NULL;
567 struct file *filp, *f = NULL;
568 struct tty_file_private *priv;
569 int closecount = 0, n;
576 spin_lock(&redirect_lock);
577 if (redirect && file_tty(redirect) == tty) {
581 spin_unlock(&redirect_lock);
585 if (test_bit(TTY_HUPPED, &tty->flags)) {
591 * Some console devices aren't actually hung up for technical and
592 * historical reasons, which can lead to indefinite interruptible
593 * sleep in n_tty_read(). The following explicitly tells
594 * n_tty_read() to abort readers.
596 set_bit(TTY_HUPPING, &tty->flags);
598 /* inuse_filps is protected by the single tty lock,
599 this really needs to change if we want to flush the
600 workqueue with the lock held */
601 check_tty_count(tty, "tty_hangup");
603 spin_lock(&tty->files_lock);
604 /* This breaks for file handles being sent over AF_UNIX sockets ? */
605 list_for_each_entry(priv, &tty->tty_files, list) {
607 if (filp->f_op->write_iter == redirected_tty_write)
609 if (filp->f_op->write_iter != tty_write)
612 __tty_fasync(-1, filp, 0); /* can't block */
613 filp->f_op = &hung_up_tty_fops;
615 spin_unlock(&tty->files_lock);
617 refs = tty_signal_session_leader(tty, exit_session);
618 /* Account for the p->signal references we killed */
622 tty_ldisc_hangup(tty, cons_filp != NULL);
624 spin_lock_irq(&tty->ctrl_lock);
625 clear_bit(TTY_THROTTLED, &tty->flags);
626 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
627 put_pid(tty->session);
631 tty->ctrl_status = 0;
632 spin_unlock_irq(&tty->ctrl_lock);
635 * If one of the devices matches a console pointer, we
636 * cannot just call hangup() because that will cause
637 * tty->count and state->count to go out of sync.
638 * So we just call close() the right number of times.
642 for (n = 0; n < closecount; n++)
643 tty->ops->close(tty, cons_filp);
644 } else if (tty->ops->hangup)
645 tty->ops->hangup(tty);
647 * We don't want to have driver/ldisc interactions beyond the ones
648 * we did here. The driver layer expects no calls after ->hangup()
649 * from the ldisc side, which is now guaranteed.
651 set_bit(TTY_HUPPED, &tty->flags);
652 clear_bit(TTY_HUPPING, &tty->flags);
659 static void do_tty_hangup(struct work_struct *work)
661 struct tty_struct *tty =
662 container_of(work, struct tty_struct, hangup_work);
664 __tty_hangup(tty, 0);
668 * tty_hangup - trigger a hangup event
669 * @tty: tty to hangup
671 * A carrier loss (virtual or otherwise) has occurred on this like
672 * schedule a hangup sequence to run after this event.
675 void tty_hangup(struct tty_struct *tty)
677 tty_debug_hangup(tty, "hangup\n");
678 schedule_work(&tty->hangup_work);
681 EXPORT_SYMBOL(tty_hangup);
684 * tty_vhangup - process vhangup
685 * @tty: tty to hangup
687 * The user has asked via system call for the terminal to be hung up.
688 * We do this synchronously so that when the syscall returns the process
689 * is complete. That guarantee is necessary for security reasons.
692 void tty_vhangup(struct tty_struct *tty)
694 tty_debug_hangup(tty, "vhangup\n");
695 __tty_hangup(tty, 0);
698 EXPORT_SYMBOL(tty_vhangup);
702 * tty_vhangup_self - process vhangup for own ctty
704 * Perform a vhangup on the current controlling tty
707 void tty_vhangup_self(void)
709 struct tty_struct *tty;
711 tty = get_current_tty();
719 * tty_vhangup_session - hangup session leader exit
720 * @tty: tty to hangup
722 * The session leader is exiting and hanging up its controlling terminal.
723 * Every process in the foreground process group is signalled SIGHUP.
725 * We do this synchronously so that when the syscall returns the process
726 * is complete. That guarantee is necessary for security reasons.
729 void tty_vhangup_session(struct tty_struct *tty)
731 tty_debug_hangup(tty, "session hangup\n");
732 __tty_hangup(tty, 1);
736 * tty_hung_up_p - was tty hung up
737 * @filp: file pointer of tty
739 * Return true if the tty has been subject to a vhangup or a carrier
743 int tty_hung_up_p(struct file *filp)
745 return (filp && filp->f_op == &hung_up_tty_fops);
748 EXPORT_SYMBOL(tty_hung_up_p);
751 * stop_tty - propagate flow control
754 * Perform flow control to the driver. May be called
755 * on an already stopped device and will not re-call the driver
758 * This functionality is used by both the line disciplines for
759 * halting incoming flow and by the driver. It may therefore be
760 * called from any context, may be under the tty atomic_write_lock
767 void __stop_tty(struct tty_struct *tty)
776 void stop_tty(struct tty_struct *tty)
780 spin_lock_irqsave(&tty->flow_lock, flags);
782 spin_unlock_irqrestore(&tty->flow_lock, flags);
784 EXPORT_SYMBOL(stop_tty);
787 * start_tty - propagate flow control
790 * Start a tty that has been stopped if at all possible. If this
791 * tty was previous stopped and is now being started, the driver
792 * start method is invoked and the line discipline woken.
798 void __start_tty(struct tty_struct *tty)
800 if (!tty->stopped || tty->flow_stopped)
804 tty->ops->start(tty);
808 void start_tty(struct tty_struct *tty)
812 spin_lock_irqsave(&tty->flow_lock, flags);
814 spin_unlock_irqrestore(&tty->flow_lock, flags);
816 EXPORT_SYMBOL(start_tty);
818 static void tty_update_time(struct timespec64 *time)
820 time64_t sec = ktime_get_real_seconds();
823 * We only care if the two values differ in anything other than the
824 * lower three bits (i.e every 8 seconds). If so, then we can update
825 * the time of the tty device, otherwise it could be construded as a
826 * security leak to let userspace know the exact timing of the tty.
828 if ((sec ^ time->tv_sec) & ~7)
833 * tty_read - read method for tty device files
834 * @file: pointer to tty file
836 * @count: size of user buffer
839 * Perform the read system call function on this terminal device. Checks
840 * for hung up devices before calling the line discipline method.
843 * Locks the line discipline internally while needed. Multiple
844 * read calls may be outstanding in parallel.
847 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
851 struct inode *inode = file_inode(file);
852 struct tty_struct *tty = file_tty(file);
853 struct tty_ldisc *ld;
855 if (tty_paranoia_check(tty, inode, "tty_read"))
857 if (!tty || tty_io_error(tty))
860 /* We want to wait for the line discipline to sort out in this
862 ld = tty_ldisc_ref_wait(tty);
864 return hung_up_tty_read(file, buf, count, ppos);
866 i = ld->ops->read(tty, file, buf, count);
872 tty_update_time(&inode->i_atime);
877 static void tty_write_unlock(struct tty_struct *tty)
879 mutex_unlock(&tty->atomic_write_lock);
880 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
883 static int tty_write_lock(struct tty_struct *tty, int ndelay)
885 if (!mutex_trylock(&tty->atomic_write_lock)) {
888 if (mutex_lock_interruptible(&tty->atomic_write_lock))
895 * Split writes up in sane blocksizes to avoid
896 * denial-of-service type attacks
898 static inline ssize_t do_tty_write(
899 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
900 struct tty_struct *tty,
902 struct iov_iter *from)
904 size_t count = iov_iter_count(from);
905 ssize_t ret, written = 0;
908 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
913 * We chunk up writes into a temporary buffer. This
914 * simplifies low-level drivers immensely, since they
915 * don't have locking issues and user mode accesses.
917 * But if TTY_NO_WRITE_SPLIT is set, we should use a
920 * The default chunk-size is 2kB, because the NTTY
921 * layer has problems with bigger chunks. It will
922 * claim to be able to handle more characters than
925 * FIXME: This can probably go away now except that 64K chunks
926 * are too likely to fail unless switched to vmalloc...
929 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
934 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
935 if (tty->write_cnt < chunk) {
936 unsigned char *buf_chunk;
941 buf_chunk = kmalloc(chunk, GFP_KERNEL);
946 kfree(tty->write_buf);
947 tty->write_cnt = chunk;
948 tty->write_buf = buf_chunk;
951 /* Do the write .. */
958 if (copy_from_iter(tty->write_buf, size, from) != size)
961 ret = write(tty, file, tty->write_buf, size);
969 /* FIXME! Have Al check this! */
971 iov_iter_revert(from, size-ret);
977 if (signal_pending(current))
982 tty_update_time(&file_inode(file)->i_mtime);
986 tty_write_unlock(tty);
991 * tty_write_message - write a message to a certain tty, not just the console.
992 * @tty: the destination tty_struct
993 * @msg: the message to write
995 * This is used for messages that need to be redirected to a specific tty.
996 * We don't put it into the syslog queue right now maybe in the future if
999 * We must still hold the BTM and test the CLOSING flag for the moment.
1002 void tty_write_message(struct tty_struct *tty, char *msg)
1005 mutex_lock(&tty->atomic_write_lock);
1007 if (tty->ops->write && tty->count > 0)
1008 tty->ops->write(tty, msg, strlen(msg));
1010 tty_write_unlock(tty);
1017 * tty_write - write method for tty device file
1018 * @file: tty file pointer
1019 * @buf: user data to write
1020 * @count: bytes to write
1023 * Write data to a tty device via the line discipline.
1026 * Locks the line discipline as required
1027 * Writes to the tty driver are serialized by the atomic_write_lock
1028 * and are then processed in chunks to the device. The line discipline
1029 * write method will not be invoked in parallel for each device.
1032 static ssize_t file_tty_write(struct file *file, struct kiocb *iocb, struct iov_iter *from)
1034 struct tty_struct *tty = file_tty(file);
1035 struct tty_ldisc *ld;
1038 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1040 if (!tty || !tty->ops->write || tty_io_error(tty))
1042 /* Short term debug to catch buggy drivers */
1043 if (tty->ops->write_room == NULL)
1044 tty_err(tty, "missing write_room method\n");
1045 ld = tty_ldisc_ref_wait(tty);
1047 return hung_up_tty_write(iocb, from);
1048 if (!ld->ops->write)
1051 ret = do_tty_write(ld->ops->write, tty, file, from);
1052 tty_ldisc_deref(ld);
1056 static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from)
1058 return file_tty_write(iocb->ki_filp, iocb, from);
1061 ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter)
1063 struct file *p = NULL;
1065 spin_lock(&redirect_lock);
1067 p = get_file(redirect);
1068 spin_unlock(&redirect_lock);
1071 * We know the redirected tty is just another tty, we can can
1072 * call file_tty_write() directly with that file pointer.
1076 res = file_tty_write(p, iocb, iter);
1080 return tty_write(iocb, iter);
1084 * tty_send_xchar - send priority character
1086 * Send a high priority character to the tty even if stopped
1088 * Locking: none for xchar method, write ordering for write method.
1091 int tty_send_xchar(struct tty_struct *tty, char ch)
1093 int was_stopped = tty->stopped;
1095 if (tty->ops->send_xchar) {
1096 down_read(&tty->termios_rwsem);
1097 tty->ops->send_xchar(tty, ch);
1098 up_read(&tty->termios_rwsem);
1102 if (tty_write_lock(tty, 0) < 0)
1103 return -ERESTARTSYS;
1105 down_read(&tty->termios_rwsem);
1108 tty->ops->write(tty, &ch, 1);
1111 up_read(&tty->termios_rwsem);
1112 tty_write_unlock(tty);
1116 static char ptychar[] = "pqrstuvwxyzabcde";
1119 * pty_line_name - generate name for a pty
1120 * @driver: the tty driver in use
1121 * @index: the minor number
1122 * @p: output buffer of at least 6 bytes
1124 * Generate a name from a driver reference and write it to the output
1129 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1131 int i = index + driver->name_base;
1132 /* ->name is initialized to "ttyp", but "tty" is expected */
1133 sprintf(p, "%s%c%x",
1134 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1135 ptychar[i >> 4 & 0xf], i & 0xf);
1139 * tty_line_name - generate name for a tty
1140 * @driver: the tty driver in use
1141 * @index: the minor number
1142 * @p: output buffer of at least 7 bytes
1144 * Generate a name from a driver reference and write it to the output
1149 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1151 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1152 return sprintf(p, "%s", driver->name);
1154 return sprintf(p, "%s%d", driver->name,
1155 index + driver->name_base);
1159 * tty_driver_lookup_tty() - find an existing tty, if any
1160 * @driver: the driver for the tty
1161 * @file: file object
1162 * @idx: the minor number
1164 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1165 * driver lookup() method returns an error.
1167 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1169 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1170 struct file *file, int idx)
1172 struct tty_struct *tty;
1174 if (driver->ops->lookup)
1176 tty = ERR_PTR(-EIO);
1178 tty = driver->ops->lookup(driver, file, idx);
1180 tty = driver->ttys[idx];
1188 * tty_init_termios - helper for termios setup
1189 * @tty: the tty to set up
1191 * Initialise the termios structure for this tty. This runs under
1192 * the tty_mutex currently so we can be relaxed about ordering.
1195 void tty_init_termios(struct tty_struct *tty)
1197 struct ktermios *tp;
1198 int idx = tty->index;
1200 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1201 tty->termios = tty->driver->init_termios;
1203 /* Check for lazy saved data */
1204 tp = tty->driver->termios[idx];
1207 tty->termios.c_line = tty->driver->init_termios.c_line;
1209 tty->termios = tty->driver->init_termios;
1211 /* Compatibility until drivers always set this */
1212 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1213 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1215 EXPORT_SYMBOL_GPL(tty_init_termios);
1217 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1219 tty_init_termios(tty);
1220 tty_driver_kref_get(driver);
1222 driver->ttys[tty->index] = tty;
1225 EXPORT_SYMBOL_GPL(tty_standard_install);
1228 * tty_driver_install_tty() - install a tty entry in the driver
1229 * @driver: the driver for the tty
1232 * Install a tty object into the driver tables. The tty->index field
1233 * will be set by the time this is called. This method is responsible
1234 * for ensuring any need additional structures are allocated and
1237 * Locking: tty_mutex for now
1239 static int tty_driver_install_tty(struct tty_driver *driver,
1240 struct tty_struct *tty)
1242 return driver->ops->install ? driver->ops->install(driver, tty) :
1243 tty_standard_install(driver, tty);
1247 * tty_driver_remove_tty() - remove a tty from the driver tables
1248 * @driver: the driver for the tty
1249 * @tty: tty to remove
1251 * Remvoe a tty object from the driver tables. The tty->index field
1252 * will be set by the time this is called.
1254 * Locking: tty_mutex for now
1256 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1258 if (driver->ops->remove)
1259 driver->ops->remove(driver, tty);
1261 driver->ttys[tty->index] = NULL;
1265 * tty_reopen() - fast re-open of an open tty
1266 * @tty: the tty to open
1268 * Return 0 on success, -errno on error.
1269 * Re-opens on master ptys are not allowed and return -EIO.
1271 * Locking: Caller must hold tty_lock
1273 static int tty_reopen(struct tty_struct *tty)
1275 struct tty_driver *driver = tty->driver;
1276 struct tty_ldisc *ld;
1279 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1280 driver->subtype == PTY_TYPE_MASTER)
1286 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1289 ld = tty_ldisc_ref_wait(tty);
1291 tty_ldisc_deref(ld);
1293 retval = tty_ldisc_lock(tty, 5 * HZ);
1298 retval = tty_ldisc_reinit(tty, tty->termios.c_line);
1299 tty_ldisc_unlock(tty);
1309 * tty_init_dev - initialise a tty device
1310 * @driver: tty driver we are opening a device on
1311 * @idx: device index
1313 * Prepare a tty device. This may not be a "new" clean device but
1314 * could also be an active device. The pty drivers require special
1315 * handling because of this.
1318 * The function is called under the tty_mutex, which
1319 * protects us from the tty struct or driver itself going away.
1321 * On exit the tty device has the line discipline attached and
1322 * a reference count of 1. If a pair was created for pty/tty use
1323 * and the other was a pty master then it too has a reference count of 1.
1325 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1326 * failed open. The new code protects the open with a mutex, so it's
1327 * really quite straightforward. The mutex locking can probably be
1328 * relaxed for the (most common) case of reopening a tty.
1330 * Return: returned tty structure
1333 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1335 struct tty_struct *tty;
1339 * First time open is complex, especially for PTY devices.
1340 * This code guarantees that either everything succeeds and the
1341 * TTY is ready for operation, or else the table slots are vacated
1342 * and the allocated memory released. (Except that the termios
1346 if (!try_module_get(driver->owner))
1347 return ERR_PTR(-ENODEV);
1349 tty = alloc_tty_struct(driver, idx);
1352 goto err_module_put;
1356 retval = tty_driver_install_tty(driver, tty);
1361 tty->port = driver->ports[idx];
1363 if (WARN_RATELIMIT(!tty->port,
1364 "%s: %s driver does not set tty->port. This would crash the kernel. Fix the driver!\n",
1365 __func__, tty->driver->name)) {
1367 goto err_release_lock;
1370 retval = tty_ldisc_lock(tty, 5 * HZ);
1372 goto err_release_lock;
1373 tty->port->itty = tty;
1376 * Structures all installed ... call the ldisc open routines.
1377 * If we fail here just call release_tty to clean up. No need
1378 * to decrement the use counts, as release_tty doesn't care.
1380 retval = tty_ldisc_setup(tty, tty->link);
1382 goto err_release_tty;
1383 tty_ldisc_unlock(tty);
1384 /* Return the tty locked so that it cannot vanish under the caller */
1389 free_tty_struct(tty);
1391 module_put(driver->owner);
1392 return ERR_PTR(retval);
1394 /* call the tty release_tty routine to clean out this slot */
1396 tty_ldisc_unlock(tty);
1397 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1401 release_tty(tty, idx);
1402 return ERR_PTR(retval);
1406 * tty_save_termios() - save tty termios data in driver table
1407 * @tty: tty whose termios data to save
1409 * Locking: Caller guarantees serialisation with tty_init_termios().
1411 void tty_save_termios(struct tty_struct *tty)
1413 struct ktermios *tp;
1414 int idx = tty->index;
1416 /* If the port is going to reset then it has no termios to save */
1417 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1420 /* Stash the termios data */
1421 tp = tty->driver->termios[idx];
1423 tp = kmalloc(sizeof(*tp), GFP_KERNEL);
1426 tty->driver->termios[idx] = tp;
1430 EXPORT_SYMBOL_GPL(tty_save_termios);
1433 * tty_flush_works - flush all works of a tty/pty pair
1434 * @tty: tty device to flush works for (or either end of a pty pair)
1436 * Sync flush all works belonging to @tty (and the 'other' tty).
1438 static void tty_flush_works(struct tty_struct *tty)
1440 flush_work(&tty->SAK_work);
1441 flush_work(&tty->hangup_work);
1443 flush_work(&tty->link->SAK_work);
1444 flush_work(&tty->link->hangup_work);
1449 * release_one_tty - release tty structure memory
1450 * @work: work of tty we are obliterating
1452 * Releases memory associated with a tty structure, and clears out the
1453 * driver table slots. This function is called when a device is no longer
1454 * in use. It also gets called when setup of a device fails.
1457 * takes the file list lock internally when working on the list
1458 * of ttys that the driver keeps.
1460 * This method gets called from a work queue so that the driver private
1461 * cleanup ops can sleep (needed for USB at least)
1463 static void release_one_tty(struct work_struct *work)
1465 struct tty_struct *tty =
1466 container_of(work, struct tty_struct, hangup_work);
1467 struct tty_driver *driver = tty->driver;
1468 struct module *owner = driver->owner;
1470 if (tty->ops->cleanup)
1471 tty->ops->cleanup(tty);
1474 tty_driver_kref_put(driver);
1477 spin_lock(&tty->files_lock);
1478 list_del_init(&tty->tty_files);
1479 spin_unlock(&tty->files_lock);
1482 put_pid(tty->session);
1483 free_tty_struct(tty);
1486 static void queue_release_one_tty(struct kref *kref)
1488 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1490 /* The hangup queue is now free so we can reuse it rather than
1491 waste a chunk of memory for each port */
1492 INIT_WORK(&tty->hangup_work, release_one_tty);
1493 schedule_work(&tty->hangup_work);
1497 * tty_kref_put - release a tty kref
1500 * Release a reference to a tty device and if need be let the kref
1501 * layer destruct the object for us
1504 void tty_kref_put(struct tty_struct *tty)
1507 kref_put(&tty->kref, queue_release_one_tty);
1509 EXPORT_SYMBOL(tty_kref_put);
1512 * release_tty - release tty structure memory
1513 * @tty: tty device release
1514 * @idx: index of the tty device release
1516 * Release both @tty and a possible linked partner (think pty pair),
1517 * and decrement the refcount of the backing module.
1521 * takes the file list lock internally when working on the list
1522 * of ttys that the driver keeps.
1525 static void release_tty(struct tty_struct *tty, int idx)
1527 /* This should always be true but check for the moment */
1528 WARN_ON(tty->index != idx);
1529 WARN_ON(!mutex_is_locked(&tty_mutex));
1530 if (tty->ops->shutdown)
1531 tty->ops->shutdown(tty);
1532 tty_save_termios(tty);
1533 tty_driver_remove_tty(tty->driver, tty);
1535 tty->port->itty = NULL;
1537 tty->link->port->itty = NULL;
1539 tty_buffer_cancel_work(tty->port);
1541 tty_buffer_cancel_work(tty->link->port);
1543 tty_kref_put(tty->link);
1548 * tty_release_checks - check a tty before real release
1549 * @tty: tty to check
1550 * @idx: index of the tty
1552 * Performs some paranoid checking before true release of the @tty.
1553 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1555 static int tty_release_checks(struct tty_struct *tty, int idx)
1557 #ifdef TTY_PARANOIA_CHECK
1558 if (idx < 0 || idx >= tty->driver->num) {
1559 tty_debug(tty, "bad idx %d\n", idx);
1563 /* not much to check for devpts */
1564 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1567 if (tty != tty->driver->ttys[idx]) {
1568 tty_debug(tty, "bad driver table[%d] = %p\n",
1569 idx, tty->driver->ttys[idx]);
1572 if (tty->driver->other) {
1573 struct tty_struct *o_tty = tty->link;
1575 if (o_tty != tty->driver->other->ttys[idx]) {
1576 tty_debug(tty, "bad other table[%d] = %p\n",
1577 idx, tty->driver->other->ttys[idx]);
1580 if (o_tty->link != tty) {
1581 tty_debug(tty, "bad link = %p\n", o_tty->link);
1590 * tty_kclose - closes tty opened by tty_kopen
1593 * Performs the final steps to release and free a tty device. It is the
1594 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1595 * flag on tty->port.
1597 void tty_kclose(struct tty_struct *tty)
1600 * Ask the line discipline code to release its structures
1602 tty_ldisc_release(tty);
1604 /* Wait for pending work before tty destruction commmences */
1605 tty_flush_works(tty);
1607 tty_debug_hangup(tty, "freeing structure\n");
1609 * The release_tty function takes care of the details of clearing
1610 * the slots and preserving the termios structure.
1612 mutex_lock(&tty_mutex);
1613 tty_port_set_kopened(tty->port, 0);
1614 release_tty(tty, tty->index);
1615 mutex_unlock(&tty_mutex);
1617 EXPORT_SYMBOL_GPL(tty_kclose);
1620 * tty_release_struct - release a tty struct
1622 * @idx: index of the tty
1624 * Performs the final steps to release and free a tty device. It is
1625 * roughly the reverse of tty_init_dev.
1627 void tty_release_struct(struct tty_struct *tty, int idx)
1630 * Ask the line discipline code to release its structures
1632 tty_ldisc_release(tty);
1634 /* Wait for pending work before tty destruction commmences */
1635 tty_flush_works(tty);
1637 tty_debug_hangup(tty, "freeing structure\n");
1639 * The release_tty function takes care of the details of clearing
1640 * the slots and preserving the termios structure.
1642 mutex_lock(&tty_mutex);
1643 release_tty(tty, idx);
1644 mutex_unlock(&tty_mutex);
1646 EXPORT_SYMBOL_GPL(tty_release_struct);
1649 * tty_release - vfs callback for close
1650 * @inode: inode of tty
1651 * @filp: file pointer for handle to tty
1653 * Called the last time each file handle is closed that references
1654 * this tty. There may however be several such references.
1657 * Takes bkl. See tty_release_dev
1659 * Even releasing the tty structures is a tricky business.. We have
1660 * to be very careful that the structures are all released at the
1661 * same time, as interrupts might otherwise get the wrong pointers.
1663 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1664 * lead to double frees or releasing memory still in use.
1667 int tty_release(struct inode *inode, struct file *filp)
1669 struct tty_struct *tty = file_tty(filp);
1670 struct tty_struct *o_tty = NULL;
1671 int do_sleep, final;
1676 if (tty_paranoia_check(tty, inode, __func__))
1680 check_tty_count(tty, __func__);
1682 __tty_fasync(-1, filp, 0);
1685 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1686 tty->driver->subtype == PTY_TYPE_MASTER)
1689 if (tty_release_checks(tty, idx)) {
1694 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1696 if (tty->ops->close)
1697 tty->ops->close(tty, filp);
1699 /* If tty is pty master, lock the slave pty (stable lock order) */
1700 tty_lock_slave(o_tty);
1703 * Sanity check: if tty->count is going to zero, there shouldn't be
1704 * any waiters on tty->read_wait or tty->write_wait. We test the
1705 * wait queues and kick everyone out _before_ actually starting to
1706 * close. This ensures that we won't block while releasing the tty
1709 * The test for the o_tty closing is necessary, since the master and
1710 * slave sides may close in any order. If the slave side closes out
1711 * first, its count will be one, since the master side holds an open.
1712 * Thus this test wouldn't be triggered at the time the slave closed,
1718 if (tty->count <= 1) {
1719 if (waitqueue_active(&tty->read_wait)) {
1720 wake_up_poll(&tty->read_wait, EPOLLIN);
1723 if (waitqueue_active(&tty->write_wait)) {
1724 wake_up_poll(&tty->write_wait, EPOLLOUT);
1728 if (o_tty && o_tty->count <= 1) {
1729 if (waitqueue_active(&o_tty->read_wait)) {
1730 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1733 if (waitqueue_active(&o_tty->write_wait)) {
1734 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1743 tty_warn(tty, "read/write wait queue active!\n");
1745 schedule_timeout_killable(timeout);
1746 if (timeout < 120 * HZ)
1747 timeout = 2 * timeout + 1;
1749 timeout = MAX_SCHEDULE_TIMEOUT;
1753 if (--o_tty->count < 0) {
1754 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1758 if (--tty->count < 0) {
1759 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1764 * We've decremented tty->count, so we need to remove this file
1765 * descriptor off the tty->tty_files list; this serves two
1767 * - check_tty_count sees the correct number of file descriptors
1768 * associated with this tty.
1769 * - do_tty_hangup no longer sees this file descriptor as
1770 * something that needs to be handled for hangups.
1775 * Perform some housekeeping before deciding whether to return.
1777 * If _either_ side is closing, make sure there aren't any
1778 * processes that still think tty or o_tty is their controlling
1782 read_lock(&tasklist_lock);
1783 session_clear_tty(tty->session);
1785 session_clear_tty(o_tty->session);
1786 read_unlock(&tasklist_lock);
1789 /* check whether both sides are closing ... */
1790 final = !tty->count && !(o_tty && o_tty->count);
1792 tty_unlock_slave(o_tty);
1795 /* At this point, the tty->count == 0 should ensure a dead tty
1796 cannot be re-opened by a racing opener */
1801 tty_debug_hangup(tty, "final close\n");
1803 tty_release_struct(tty, idx);
1808 * tty_open_current_tty - get locked tty of current task
1809 * @device: device number
1810 * @filp: file pointer to tty
1811 * @return: locked tty of the current task iff @device is /dev/tty
1813 * Performs a re-open of the current task's controlling tty.
1815 * We cannot return driver and index like for the other nodes because
1816 * devpts will not work then. It expects inodes to be from devpts FS.
1818 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1820 struct tty_struct *tty;
1823 if (device != MKDEV(TTYAUX_MAJOR, 0))
1826 tty = get_current_tty();
1828 return ERR_PTR(-ENXIO);
1830 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1833 tty_kref_put(tty); /* safe to drop the kref now */
1835 retval = tty_reopen(tty);
1838 tty = ERR_PTR(retval);
1844 * tty_lookup_driver - lookup a tty driver for a given device file
1845 * @device: device number
1846 * @filp: file pointer to tty
1847 * @index: index for the device in the @return driver
1848 * @return: driver for this inode (with increased refcount)
1850 * If @return is not erroneous, the caller is responsible to decrement the
1851 * refcount by tty_driver_kref_put.
1853 * Locking: tty_mutex protects get_tty_driver
1855 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1858 struct tty_driver *driver = NULL;
1862 case MKDEV(TTY_MAJOR, 0): {
1863 extern struct tty_driver *console_driver;
1864 driver = tty_driver_kref_get(console_driver);
1865 *index = fg_console;
1869 case MKDEV(TTYAUX_MAJOR, 1): {
1870 struct tty_driver *console_driver = console_device(index);
1871 if (console_driver) {
1872 driver = tty_driver_kref_get(console_driver);
1873 if (driver && filp) {
1874 /* Don't let /dev/console block */
1875 filp->f_flags |= O_NONBLOCK;
1880 tty_driver_kref_put(driver);
1881 return ERR_PTR(-ENODEV);
1884 driver = get_tty_driver(device, index);
1886 return ERR_PTR(-ENODEV);
1893 * tty_kopen - open a tty device for kernel
1894 * @device: dev_t of device to open
1896 * Opens tty exclusively for kernel. Performs the driver lookup,
1897 * makes sure it's not already opened and performs the first-time
1898 * tty initialization.
1900 * Returns the locked initialized &tty_struct
1902 * Claims the global tty_mutex to serialize:
1903 * - concurrent first-time tty initialization
1904 * - concurrent tty driver removal w/ lookup
1905 * - concurrent tty removal from driver table
1907 struct tty_struct *tty_kopen(dev_t device)
1909 struct tty_struct *tty;
1910 struct tty_driver *driver;
1913 mutex_lock(&tty_mutex);
1914 driver = tty_lookup_driver(device, NULL, &index);
1915 if (IS_ERR(driver)) {
1916 mutex_unlock(&tty_mutex);
1917 return ERR_CAST(driver);
1920 /* check whether we're reopening an existing tty */
1921 tty = tty_driver_lookup_tty(driver, NULL, index);
1926 /* drop kref from tty_driver_lookup_tty() */
1928 tty = ERR_PTR(-EBUSY);
1929 } else { /* tty_init_dev returns tty with the tty_lock held */
1930 tty = tty_init_dev(driver, index);
1933 tty_port_set_kopened(tty->port, 1);
1936 mutex_unlock(&tty_mutex);
1937 tty_driver_kref_put(driver);
1940 EXPORT_SYMBOL_GPL(tty_kopen);
1943 * tty_open_by_driver - open a tty device
1944 * @device: dev_t of device to open
1945 * @filp: file pointer to tty
1947 * Performs the driver lookup, checks for a reopen, or otherwise
1948 * performs the first-time tty initialization.
1950 * Returns the locked initialized or re-opened &tty_struct
1952 * Claims the global tty_mutex to serialize:
1953 * - concurrent first-time tty initialization
1954 * - concurrent tty driver removal w/ lookup
1955 * - concurrent tty removal from driver table
1957 static struct tty_struct *tty_open_by_driver(dev_t device,
1960 struct tty_struct *tty;
1961 struct tty_driver *driver = NULL;
1965 mutex_lock(&tty_mutex);
1966 driver = tty_lookup_driver(device, filp, &index);
1967 if (IS_ERR(driver)) {
1968 mutex_unlock(&tty_mutex);
1969 return ERR_CAST(driver);
1972 /* check whether we're reopening an existing tty */
1973 tty = tty_driver_lookup_tty(driver, filp, index);
1975 mutex_unlock(&tty_mutex);
1980 if (tty_port_kopened(tty->port)) {
1982 mutex_unlock(&tty_mutex);
1983 tty = ERR_PTR(-EBUSY);
1986 mutex_unlock(&tty_mutex);
1987 retval = tty_lock_interruptible(tty);
1988 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
1990 if (retval == -EINTR)
1991 retval = -ERESTARTSYS;
1992 tty = ERR_PTR(retval);
1995 retval = tty_reopen(tty);
1998 tty = ERR_PTR(retval);
2000 } else { /* Returns with the tty_lock held for now */
2001 tty = tty_init_dev(driver, index);
2002 mutex_unlock(&tty_mutex);
2005 tty_driver_kref_put(driver);
2010 * tty_open - open a tty device
2011 * @inode: inode of device file
2012 * @filp: file pointer to tty
2014 * tty_open and tty_release keep up the tty count that contains the
2015 * number of opens done on a tty. We cannot use the inode-count, as
2016 * different inodes might point to the same tty.
2018 * Open-counting is needed for pty masters, as well as for keeping
2019 * track of serial lines: DTR is dropped when the last close happens.
2020 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2022 * The termios state of a pty is reset on first open so that
2023 * settings don't persist across reuse.
2025 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2026 * tty->count should protect the rest.
2027 * ->siglock protects ->signal/->sighand
2029 * Note: the tty_unlock/lock cases without a ref are only safe due to
2033 static int tty_open(struct inode *inode, struct file *filp)
2035 struct tty_struct *tty;
2037 dev_t device = inode->i_rdev;
2038 unsigned saved_flags = filp->f_flags;
2040 nonseekable_open(inode, filp);
2043 retval = tty_alloc_file(filp);
2047 tty = tty_open_current_tty(device, filp);
2049 tty = tty_open_by_driver(device, filp);
2052 tty_free_file(filp);
2053 retval = PTR_ERR(tty);
2054 if (retval != -EAGAIN || signal_pending(current))
2060 tty_add_file(tty, filp);
2062 check_tty_count(tty, __func__);
2063 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2066 retval = tty->ops->open(tty, filp);
2069 filp->f_flags = saved_flags;
2072 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2074 tty_unlock(tty); /* need to call tty_release without BTM */
2075 tty_release(inode, filp);
2076 if (retval != -ERESTARTSYS)
2079 if (signal_pending(current))
2084 * Need to reset f_op in case a hangup happened.
2086 if (tty_hung_up_p(filp))
2087 filp->f_op = &tty_fops;
2090 clear_bit(TTY_HUPPED, &tty->flags);
2092 noctty = (filp->f_flags & O_NOCTTY) ||
2093 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2094 device == MKDEV(TTYAUX_MAJOR, 1) ||
2095 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2096 tty->driver->subtype == PTY_TYPE_MASTER);
2098 tty_open_proc_set_tty(filp, tty);
2106 * tty_poll - check tty status
2107 * @filp: file being polled
2108 * @wait: poll wait structures to update
2110 * Call the line discipline polling method to obtain the poll
2111 * status of the device.
2113 * Locking: locks called line discipline but ldisc poll method
2114 * may be re-entered freely by other callers.
2117 static __poll_t tty_poll(struct file *filp, poll_table *wait)
2119 struct tty_struct *tty = file_tty(filp);
2120 struct tty_ldisc *ld;
2123 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2126 ld = tty_ldisc_ref_wait(tty);
2128 return hung_up_tty_poll(filp, wait);
2130 ret = ld->ops->poll(tty, filp, wait);
2131 tty_ldisc_deref(ld);
2135 static int __tty_fasync(int fd, struct file *filp, int on)
2137 struct tty_struct *tty = file_tty(filp);
2138 unsigned long flags;
2141 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2144 retval = fasync_helper(fd, filp, on, &tty->fasync);
2152 spin_lock_irqsave(&tty->ctrl_lock, flags);
2155 type = PIDTYPE_PGID;
2157 pid = task_pid(current);
2158 type = PIDTYPE_TGID;
2161 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2162 __f_setown(filp, pid, type, 0);
2170 static int tty_fasync(int fd, struct file *filp, int on)
2172 struct tty_struct *tty = file_tty(filp);
2173 int retval = -ENOTTY;
2176 if (!tty_hung_up_p(filp))
2177 retval = __tty_fasync(fd, filp, on);
2184 * tiocsti - fake input character
2185 * @tty: tty to fake input into
2186 * @p: pointer to character
2188 * Fake input to a tty device. Does the necessary locking and
2191 * FIXME: does not honour flow control ??
2194 * Called functions take tty_ldiscs_lock
2195 * current->signal->tty check is safe without locks
2197 * FIXME: may race normal receive processing
2200 static int tiocsti(struct tty_struct *tty, char __user *p)
2203 struct tty_ldisc *ld;
2205 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2207 if (get_user(ch, p))
2209 tty_audit_tiocsti(tty, ch);
2210 ld = tty_ldisc_ref_wait(tty);
2213 if (ld->ops->receive_buf)
2214 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2215 tty_ldisc_deref(ld);
2220 * tiocgwinsz - implement window query ioctl
2222 * @arg: user buffer for result
2224 * Copies the kernel idea of the window size into the user buffer.
2226 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2230 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2234 mutex_lock(&tty->winsize_mutex);
2235 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2236 mutex_unlock(&tty->winsize_mutex);
2238 return err ? -EFAULT: 0;
2242 * tty_do_resize - resize event
2243 * @tty: tty being resized
2244 * @ws: new dimensions
2246 * Update the termios variables and send the necessary signals to
2247 * peform a terminal resize correctly
2250 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2255 mutex_lock(&tty->winsize_mutex);
2256 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2259 /* Signal the foreground process group */
2260 pgrp = tty_get_pgrp(tty);
2262 kill_pgrp(pgrp, SIGWINCH, 1);
2267 mutex_unlock(&tty->winsize_mutex);
2270 EXPORT_SYMBOL(tty_do_resize);
2273 * tiocswinsz - implement window size set ioctl
2274 * @tty: tty side of tty
2275 * @arg: user buffer for result
2277 * Copies the user idea of the window size to the kernel. Traditionally
2278 * this is just advisory information but for the Linux console it
2279 * actually has driver level meaning and triggers a VC resize.
2282 * Driver dependent. The default do_resize method takes the
2283 * tty termios mutex and ctrl_lock. The console takes its own lock
2284 * then calls into the default method.
2287 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2289 struct winsize tmp_ws;
2290 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2293 if (tty->ops->resize)
2294 return tty->ops->resize(tty, &tmp_ws);
2296 return tty_do_resize(tty, &tmp_ws);
2300 * tioccons - allow admin to move logical console
2301 * @file: the file to become console
2303 * Allow the administrator to move the redirected console device
2305 * Locking: uses redirect_lock to guard the redirect information
2308 static int tioccons(struct file *file)
2310 if (!capable(CAP_SYS_ADMIN))
2312 if (file->f_op->write_iter == redirected_tty_write) {
2314 spin_lock(&redirect_lock);
2317 spin_unlock(&redirect_lock);
2322 if (file->f_op->write_iter != tty_write)
2324 if (!(file->f_mode & FMODE_WRITE))
2326 if (!(file->f_mode & FMODE_CAN_WRITE))
2328 spin_lock(&redirect_lock);
2330 spin_unlock(&redirect_lock);
2333 redirect = get_file(file);
2334 spin_unlock(&redirect_lock);
2339 * tiocsetd - set line discipline
2341 * @p: pointer to user data
2343 * Set the line discipline according to user request.
2345 * Locking: see tty_set_ldisc, this function is just a helper
2348 static int tiocsetd(struct tty_struct *tty, int __user *p)
2353 if (get_user(disc, p))
2356 ret = tty_set_ldisc(tty, disc);
2362 * tiocgetd - get line discipline
2364 * @p: pointer to user data
2366 * Retrieves the line discipline id directly from the ldisc.
2368 * Locking: waits for ldisc reference (in case the line discipline
2369 * is changing or the tty is being hungup)
2372 static int tiocgetd(struct tty_struct *tty, int __user *p)
2374 struct tty_ldisc *ld;
2377 ld = tty_ldisc_ref_wait(tty);
2380 ret = put_user(ld->ops->num, p);
2381 tty_ldisc_deref(ld);
2386 * send_break - performed time break
2387 * @tty: device to break on
2388 * @duration: timeout in mS
2390 * Perform a timed break on hardware that lacks its own driver level
2391 * timed break functionality.
2394 * atomic_write_lock serializes
2398 static int send_break(struct tty_struct *tty, unsigned int duration)
2402 if (tty->ops->break_ctl == NULL)
2405 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2406 retval = tty->ops->break_ctl(tty, duration);
2408 /* Do the work ourselves */
2409 if (tty_write_lock(tty, 0) < 0)
2411 retval = tty->ops->break_ctl(tty, -1);
2414 if (!signal_pending(current))
2415 msleep_interruptible(duration);
2416 retval = tty->ops->break_ctl(tty, 0);
2418 tty_write_unlock(tty);
2419 if (signal_pending(current))
2426 * tty_tiocmget - get modem status
2428 * @p: pointer to result
2430 * Obtain the modem status bits from the tty driver if the feature
2431 * is supported. Return -EINVAL if it is not available.
2433 * Locking: none (up to the driver)
2436 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2438 int retval = -EINVAL;
2440 if (tty->ops->tiocmget) {
2441 retval = tty->ops->tiocmget(tty);
2444 retval = put_user(retval, p);
2450 * tty_tiocmset - set modem status
2452 * @cmd: command - clear bits, set bits or set all
2453 * @p: pointer to desired bits
2455 * Set the modem status bits from the tty driver if the feature
2456 * is supported. Return -EINVAL if it is not available.
2458 * Locking: none (up to the driver)
2461 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2465 unsigned int set, clear, val;
2467 if (tty->ops->tiocmset == NULL)
2470 retval = get_user(val, p);
2486 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2487 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2488 return tty->ops->tiocmset(tty, set, clear);
2491 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2493 int retval = -EINVAL;
2494 struct serial_icounter_struct icount;
2495 memset(&icount, 0, sizeof(icount));
2496 if (tty->ops->get_icount)
2497 retval = tty->ops->get_icount(tty, &icount);
2500 if (copy_to_user(arg, &icount, sizeof(icount)))
2505 static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
2507 static DEFINE_RATELIMIT_STATE(depr_flags,
2508 DEFAULT_RATELIMIT_INTERVAL,
2509 DEFAULT_RATELIMIT_BURST);
2510 char comm[TASK_COMM_LEN];
2511 struct serial_struct v;
2514 if (copy_from_user(&v, ss, sizeof(*ss)))
2517 flags = v.flags & ASYNC_DEPRECATED;
2519 if (flags && __ratelimit(&depr_flags))
2520 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2521 __func__, get_task_comm(comm, current), flags);
2522 if (!tty->ops->set_serial)
2524 return tty->ops->set_serial(tty, &v);
2527 static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
2529 struct serial_struct v;
2532 memset(&v, 0, sizeof(v));
2533 if (!tty->ops->get_serial)
2535 err = tty->ops->get_serial(tty, &v);
2536 if (!err && copy_to_user(ss, &v, sizeof(v)))
2542 * if pty, return the slave side (real_tty)
2543 * otherwise, return self
2545 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2547 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2548 tty->driver->subtype == PTY_TYPE_MASTER)
2554 * Split this up, as gcc can choke on it otherwise..
2556 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2558 struct tty_struct *tty = file_tty(file);
2559 struct tty_struct *real_tty;
2560 void __user *p = (void __user *)arg;
2562 struct tty_ldisc *ld;
2564 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2567 real_tty = tty_pair_get_tty(tty);
2570 * Factor out some common prep work
2578 retval = tty_check_change(tty);
2581 if (cmd != TIOCCBRK) {
2582 tty_wait_until_sent(tty, 0);
2583 if (signal_pending(current))
2594 return tiocsti(tty, p);
2596 return tiocgwinsz(real_tty, p);
2598 return tiocswinsz(real_tty, p);
2600 return real_tty != tty ? -EINVAL : tioccons(file);
2602 set_bit(TTY_EXCLUSIVE, &tty->flags);
2605 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2609 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2610 return put_user(excl, (int __user *)p);
2613 return tiocgetd(tty, p);
2615 return tiocsetd(tty, p);
2617 if (!capable(CAP_SYS_ADMIN))
2623 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2624 return put_user(ret, (unsigned int __user *)p);
2629 case TIOCSBRK: /* Turn break on, unconditionally */
2630 if (tty->ops->break_ctl)
2631 return tty->ops->break_ctl(tty, -1);
2633 case TIOCCBRK: /* Turn break off, unconditionally */
2634 if (tty->ops->break_ctl)
2635 return tty->ops->break_ctl(tty, 0);
2637 case TCSBRK: /* SVID version: non-zero arg --> no break */
2638 /* non-zero arg means wait for all output data
2639 * to be sent (performed above) but don't send break.
2640 * This is used by the tcdrain() termios function.
2643 return send_break(tty, 250);
2645 case TCSBRKP: /* support for POSIX tcsendbreak() */
2646 return send_break(tty, arg ? arg*100 : 250);
2649 return tty_tiocmget(tty, p);
2653 return tty_tiocmset(tty, cmd, p);
2655 return tty_tiocgicount(tty, p);
2660 /* flush tty buffer and allow ldisc to process ioctl */
2661 tty_buffer_flush(tty, NULL);
2666 return tty_tiocsserial(tty, p);
2668 return tty_tiocgserial(tty, p);
2670 /* Special because the struct file is needed */
2671 return ptm_open_peer(file, tty, (int)arg);
2673 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2674 if (retval != -ENOIOCTLCMD)
2677 if (tty->ops->ioctl) {
2678 retval = tty->ops->ioctl(tty, cmd, arg);
2679 if (retval != -ENOIOCTLCMD)
2682 ld = tty_ldisc_ref_wait(tty);
2684 return hung_up_tty_ioctl(file, cmd, arg);
2686 if (ld->ops->ioctl) {
2687 retval = ld->ops->ioctl(tty, file, cmd, arg);
2688 if (retval == -ENOIOCTLCMD)
2691 tty_ldisc_deref(ld);
2695 #ifdef CONFIG_COMPAT
2697 struct serial_struct32 {
2703 compat_int_t xmit_fifo_size;
2704 compat_int_t custom_divisor;
2705 compat_int_t baud_base;
2706 unsigned short close_delay;
2710 unsigned short closing_wait; /* time to wait before closing */
2711 unsigned short closing_wait2; /* no longer used... */
2712 compat_uint_t iomem_base;
2713 unsigned short iomem_reg_shift;
2714 unsigned int port_high;
2715 /* compat_ulong_t iomap_base FIXME */
2716 compat_int_t reserved;
2719 static int compat_tty_tiocsserial(struct tty_struct *tty,
2720 struct serial_struct32 __user *ss)
2722 static DEFINE_RATELIMIT_STATE(depr_flags,
2723 DEFAULT_RATELIMIT_INTERVAL,
2724 DEFAULT_RATELIMIT_BURST);
2725 char comm[TASK_COMM_LEN];
2726 struct serial_struct32 v32;
2727 struct serial_struct v;
2730 if (copy_from_user(&v32, ss, sizeof(*ss)))
2733 memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base));
2734 v.iomem_base = compat_ptr(v32.iomem_base);
2735 v.iomem_reg_shift = v32.iomem_reg_shift;
2736 v.port_high = v32.port_high;
2739 flags = v.flags & ASYNC_DEPRECATED;
2741 if (flags && __ratelimit(&depr_flags))
2742 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2743 __func__, get_task_comm(comm, current), flags);
2744 if (!tty->ops->set_serial)
2746 return tty->ops->set_serial(tty, &v);
2749 static int compat_tty_tiocgserial(struct tty_struct *tty,
2750 struct serial_struct32 __user *ss)
2752 struct serial_struct32 v32;
2753 struct serial_struct v;
2756 memset(&v, 0, sizeof(v));
2757 memset(&v32, 0, sizeof(v32));
2759 if (!tty->ops->get_serial)
2761 err = tty->ops->get_serial(tty, &v);
2763 memcpy(&v32, &v, offsetof(struct serial_struct32, iomem_base));
2764 v32.iomem_base = (unsigned long)v.iomem_base >> 32 ?
2765 0xfffffff : ptr_to_compat(v.iomem_base);
2766 v32.iomem_reg_shift = v.iomem_reg_shift;
2767 v32.port_high = v.port_high;
2768 if (copy_to_user(ss, &v32, sizeof(v32)))
2773 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2776 struct tty_struct *tty = file_tty(file);
2777 struct tty_ldisc *ld;
2778 int retval = -ENOIOCTLCMD;
2827 case TIOCGLCKTRMIOS:
2828 case TIOCSLCKTRMIOS:
2840 return tty_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2856 return tty_ioctl(file, cmd, arg);
2859 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2864 return compat_tty_tiocsserial(tty, compat_ptr(arg));
2866 return compat_tty_tiocgserial(tty, compat_ptr(arg));
2868 if (tty->ops->compat_ioctl) {
2869 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2870 if (retval != -ENOIOCTLCMD)
2874 ld = tty_ldisc_ref_wait(tty);
2876 return hung_up_tty_compat_ioctl(file, cmd, arg);
2877 if (ld->ops->compat_ioctl)
2878 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2879 if (retval == -ENOIOCTLCMD && ld->ops->ioctl)
2880 retval = ld->ops->ioctl(tty, file,
2881 (unsigned long)compat_ptr(cmd), arg);
2882 tty_ldisc_deref(ld);
2888 static int this_tty(const void *t, struct file *file, unsigned fd)
2890 if (likely(file->f_op->read != tty_read))
2892 return file_tty(file) != t ? 0 : fd + 1;
2896 * This implements the "Secure Attention Key" --- the idea is to
2897 * prevent trojan horses by killing all processes associated with this
2898 * tty when the user hits the "Secure Attention Key". Required for
2899 * super-paranoid applications --- see the Orange Book for more details.
2901 * This code could be nicer; ideally it should send a HUP, wait a few
2902 * seconds, then send a INT, and then a KILL signal. But you then
2903 * have to coordinate with the init process, since all processes associated
2904 * with the current tty must be dead before the new getty is allowed
2907 * Now, if it would be correct ;-/ The current code has a nasty hole -
2908 * it doesn't catch files in flight. We may send the descriptor to ourselves
2909 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2911 * Nasty bug: do_SAK is being called in interrupt context. This can
2912 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2914 void __do_SAK(struct tty_struct *tty)
2919 struct task_struct *g, *p;
2920 struct pid *session;
2922 unsigned long flags;
2927 spin_lock_irqsave(&tty->ctrl_lock, flags);
2928 session = get_pid(tty->session);
2929 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2931 tty_ldisc_flush(tty);
2933 tty_driver_flush_buffer(tty);
2935 read_lock(&tasklist_lock);
2936 /* Kill the entire session */
2937 do_each_pid_task(session, PIDTYPE_SID, p) {
2938 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
2939 task_pid_nr(p), p->comm);
2940 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
2941 } while_each_pid_task(session, PIDTYPE_SID, p);
2943 /* Now kill any processes that happen to have the tty open */
2944 do_each_thread(g, p) {
2945 if (p->signal->tty == tty) {
2946 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
2947 task_pid_nr(p), p->comm);
2948 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
2952 i = iterate_fd(p->files, 0, this_tty, tty);
2954 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
2955 task_pid_nr(p), p->comm, i - 1);
2956 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
2959 } while_each_thread(g, p);
2960 read_unlock(&tasklist_lock);
2965 static void do_SAK_work(struct work_struct *work)
2967 struct tty_struct *tty =
2968 container_of(work, struct tty_struct, SAK_work);
2973 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2974 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2975 * the values which we write to it will be identical to the values which it
2976 * already has. --akpm
2978 void do_SAK(struct tty_struct *tty)
2982 schedule_work(&tty->SAK_work);
2985 EXPORT_SYMBOL(do_SAK);
2987 /* Must put_device() after it's unused! */
2988 static struct device *tty_get_device(struct tty_struct *tty)
2990 dev_t devt = tty_devnum(tty);
2991 return class_find_device_by_devt(tty_class, devt);
2998 * This subroutine allocates and initializes a tty structure.
3000 * Locking: none - tty in question is not exposed at this point
3003 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3005 struct tty_struct *tty;
3007 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3011 kref_init(&tty->kref);
3012 tty->magic = TTY_MAGIC;
3013 if (tty_ldisc_init(tty)) {
3017 tty->session = NULL;
3019 mutex_init(&tty->legacy_mutex);
3020 mutex_init(&tty->throttle_mutex);
3021 init_rwsem(&tty->termios_rwsem);
3022 mutex_init(&tty->winsize_mutex);
3023 init_ldsem(&tty->ldisc_sem);
3024 init_waitqueue_head(&tty->write_wait);
3025 init_waitqueue_head(&tty->read_wait);
3026 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3027 mutex_init(&tty->atomic_write_lock);
3028 spin_lock_init(&tty->ctrl_lock);
3029 spin_lock_init(&tty->flow_lock);
3030 spin_lock_init(&tty->files_lock);
3031 INIT_LIST_HEAD(&tty->tty_files);
3032 INIT_WORK(&tty->SAK_work, do_SAK_work);
3034 tty->driver = driver;
3035 tty->ops = driver->ops;
3037 tty_line_name(driver, idx, tty->name);
3038 tty->dev = tty_get_device(tty);
3044 * tty_put_char - write one character to a tty
3048 * Write one byte to the tty using the provided put_char method
3049 * if present. Returns the number of characters successfully output.
3051 * Note: the specific put_char operation in the driver layer may go
3052 * away soon. Don't call it directly, use this method
3055 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3057 if (tty->ops->put_char)
3058 return tty->ops->put_char(tty, ch);
3059 return tty->ops->write(tty, &ch, 1);
3061 EXPORT_SYMBOL_GPL(tty_put_char);
3063 struct class *tty_class;
3065 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3066 unsigned int index, unsigned int count)
3070 /* init here, since reused cdevs cause crashes */
3071 driver->cdevs[index] = cdev_alloc();
3072 if (!driver->cdevs[index])
3074 driver->cdevs[index]->ops = &tty_fops;
3075 driver->cdevs[index]->owner = driver->owner;
3076 err = cdev_add(driver->cdevs[index], dev, count);
3078 kobject_put(&driver->cdevs[index]->kobj);
3083 * tty_register_device - register a tty device
3084 * @driver: the tty driver that describes the tty device
3085 * @index: the index in the tty driver for this tty device
3086 * @device: a struct device that is associated with this tty device.
3087 * This field is optional, if there is no known struct device
3088 * for this tty device it can be set to NULL safely.
3090 * Returns a pointer to the struct device for this tty device
3091 * (or ERR_PTR(-EFOO) on error).
3093 * This call is required to be made to register an individual tty device
3094 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3095 * that bit is not set, this function should not be called by a tty
3101 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3102 struct device *device)
3104 return tty_register_device_attr(driver, index, device, NULL, NULL);
3106 EXPORT_SYMBOL(tty_register_device);
3108 static void tty_device_create_release(struct device *dev)
3110 dev_dbg(dev, "releasing...\n");
3115 * tty_register_device_attr - register a tty device
3116 * @driver: the tty driver that describes the tty device
3117 * @index: the index in the tty driver for this tty device
3118 * @device: a struct device that is associated with this tty device.
3119 * This field is optional, if there is no known struct device
3120 * for this tty device it can be set to NULL safely.
3121 * @drvdata: Driver data to be set to device.
3122 * @attr_grp: Attribute group to be set on device.
3124 * Returns a pointer to the struct device for this tty device
3125 * (or ERR_PTR(-EFOO) on error).
3127 * This call is required to be made to register an individual tty device
3128 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3129 * that bit is not set, this function should not be called by a tty
3134 struct device *tty_register_device_attr(struct tty_driver *driver,
3135 unsigned index, struct device *device,
3137 const struct attribute_group **attr_grp)
3140 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3141 struct ktermios *tp;
3145 if (index >= driver->num) {
3146 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3147 driver->name, index);
3148 return ERR_PTR(-EINVAL);
3151 if (driver->type == TTY_DRIVER_TYPE_PTY)
3152 pty_line_name(driver, index, name);
3154 tty_line_name(driver, index, name);
3156 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3158 return ERR_PTR(-ENOMEM);
3161 dev->class = tty_class;
3162 dev->parent = device;
3163 dev->release = tty_device_create_release;
3164 dev_set_name(dev, "%s", name);
3165 dev->groups = attr_grp;
3166 dev_set_drvdata(dev, drvdata);
3168 dev_set_uevent_suppress(dev, 1);
3170 retval = device_register(dev);
3174 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3176 * Free any saved termios data so that the termios state is
3177 * reset when reusing a minor number.
3179 tp = driver->termios[index];
3181 driver->termios[index] = NULL;
3185 retval = tty_cdev_add(driver, devt, index, 1);
3190 dev_set_uevent_suppress(dev, 0);
3191 kobject_uevent(&dev->kobj, KOBJ_ADD);
3200 return ERR_PTR(retval);
3202 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3205 * tty_unregister_device - unregister a tty device
3206 * @driver: the tty driver that describes the tty device
3207 * @index: the index in the tty driver for this tty device
3209 * If a tty device is registered with a call to tty_register_device() then
3210 * this function must be called when the tty device is gone.
3215 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3217 device_destroy(tty_class,
3218 MKDEV(driver->major, driver->minor_start) + index);
3219 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3220 cdev_del(driver->cdevs[index]);
3221 driver->cdevs[index] = NULL;
3224 EXPORT_SYMBOL(tty_unregister_device);
3227 * __tty_alloc_driver -- allocate tty driver
3228 * @lines: count of lines this driver can handle at most
3229 * @owner: module which is responsible for this driver
3230 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3232 * This should not be called directly, some of the provided macros should be
3233 * used instead. Use IS_ERR and friends on @retval.
3235 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3236 unsigned long flags)
3238 struct tty_driver *driver;
3239 unsigned int cdevs = 1;
3242 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3243 return ERR_PTR(-EINVAL);
3245 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
3247 return ERR_PTR(-ENOMEM);
3249 kref_init(&driver->kref);
3250 driver->magic = TTY_DRIVER_MAGIC;
3251 driver->num = lines;
3252 driver->owner = owner;
3253 driver->flags = flags;
3255 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3256 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3258 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3260 if (!driver->ttys || !driver->termios) {
3266 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3267 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3269 if (!driver->ports) {
3276 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3277 if (!driver->cdevs) {
3284 kfree(driver->ports);
3285 kfree(driver->ttys);
3286 kfree(driver->termios);
3287 kfree(driver->cdevs);
3289 return ERR_PTR(err);
3291 EXPORT_SYMBOL(__tty_alloc_driver);
3293 static void destruct_tty_driver(struct kref *kref)
3295 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3297 struct ktermios *tp;
3299 if (driver->flags & TTY_DRIVER_INSTALLED) {
3300 for (i = 0; i < driver->num; i++) {
3301 tp = driver->termios[i];
3303 driver->termios[i] = NULL;
3306 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3307 tty_unregister_device(driver, i);
3309 proc_tty_unregister_driver(driver);
3310 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3311 cdev_del(driver->cdevs[0]);
3313 kfree(driver->cdevs);
3314 kfree(driver->ports);
3315 kfree(driver->termios);
3316 kfree(driver->ttys);
3320 void tty_driver_kref_put(struct tty_driver *driver)
3322 kref_put(&driver->kref, destruct_tty_driver);
3324 EXPORT_SYMBOL(tty_driver_kref_put);
3326 void tty_set_operations(struct tty_driver *driver,
3327 const struct tty_operations *op)
3331 EXPORT_SYMBOL(tty_set_operations);
3333 void put_tty_driver(struct tty_driver *d)
3335 tty_driver_kref_put(d);
3337 EXPORT_SYMBOL(put_tty_driver);
3340 * Called by a tty driver to register itself.
3342 int tty_register_driver(struct tty_driver *driver)
3349 if (!driver->major) {
3350 error = alloc_chrdev_region(&dev, driver->minor_start,
3351 driver->num, driver->name);
3353 driver->major = MAJOR(dev);
3354 driver->minor_start = MINOR(dev);
3357 dev = MKDEV(driver->major, driver->minor_start);
3358 error = register_chrdev_region(dev, driver->num, driver->name);
3363 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3364 error = tty_cdev_add(driver, dev, 0, driver->num);
3366 goto err_unreg_char;
3369 mutex_lock(&tty_mutex);
3370 list_add(&driver->tty_drivers, &tty_drivers);
3371 mutex_unlock(&tty_mutex);
3373 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3374 for (i = 0; i < driver->num; i++) {
3375 d = tty_register_device(driver, i, NULL);
3378 goto err_unreg_devs;
3382 proc_tty_register_driver(driver);
3383 driver->flags |= TTY_DRIVER_INSTALLED;
3387 for (i--; i >= 0; i--)
3388 tty_unregister_device(driver, i);
3390 mutex_lock(&tty_mutex);
3391 list_del(&driver->tty_drivers);
3392 mutex_unlock(&tty_mutex);
3395 unregister_chrdev_region(dev, driver->num);
3399 EXPORT_SYMBOL(tty_register_driver);
3402 * Called by a tty driver to unregister itself.
3404 int tty_unregister_driver(struct tty_driver *driver)
3408 if (driver->refcount)
3411 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3413 mutex_lock(&tty_mutex);
3414 list_del(&driver->tty_drivers);
3415 mutex_unlock(&tty_mutex);
3419 EXPORT_SYMBOL(tty_unregister_driver);
3421 dev_t tty_devnum(struct tty_struct *tty)
3423 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3425 EXPORT_SYMBOL(tty_devnum);
3427 void tty_default_fops(struct file_operations *fops)
3432 static char *tty_devnode(struct device *dev, umode_t *mode)
3436 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3437 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3442 static int __init tty_class_init(void)
3444 tty_class = class_create(THIS_MODULE, "tty");
3445 if (IS_ERR(tty_class))
3446 return PTR_ERR(tty_class);
3447 tty_class->devnode = tty_devnode;
3451 postcore_initcall(tty_class_init);
3453 /* 3/2004 jmc: why do these devices exist? */
3454 static struct cdev tty_cdev, console_cdev;
3456 static ssize_t show_cons_active(struct device *dev,
3457 struct device_attribute *attr, char *buf)
3459 struct console *cs[16];
3465 for_each_console(c) {
3470 if ((c->flags & CON_ENABLED) == 0)
3473 if (i >= ARRAY_SIZE(cs))
3477 int index = cs[i]->index;
3478 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3480 /* don't resolve tty0 as some programs depend on it */
3481 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3482 count += tty_line_name(drv, index, buf + count);
3484 count += sprintf(buf + count, "%s%d",
3485 cs[i]->name, cs[i]->index);
3487 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3493 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3495 static struct attribute *cons_dev_attrs[] = {
3496 &dev_attr_active.attr,
3500 ATTRIBUTE_GROUPS(cons_dev);
3502 static struct device *consdev;
3504 void console_sysfs_notify(void)
3507 sysfs_notify(&consdev->kobj, NULL, "active");
3511 * Ok, now we can initialize the rest of the tty devices and can count
3512 * on memory allocations, interrupts etc..
3514 int __init tty_init(void)
3517 cdev_init(&tty_cdev, &tty_fops);
3518 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3519 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3520 panic("Couldn't register /dev/tty driver\n");
3521 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3523 cdev_init(&console_cdev, &console_fops);
3524 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3525 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3526 panic("Couldn't register /dev/console driver\n");
3527 consdev = device_create_with_groups(tty_class, NULL,
3528 MKDEV(TTYAUX_MAJOR, 1), NULL,
3529 cons_dev_groups, "console");
3530 if (IS_ERR(consdev))
3534 vty_init(&console_fops);