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>
101 #include <linux/uaccess.h>
103 #include <linux/kbd_kern.h>
104 #include <linux/vt_kern.h>
105 #include <linux/selection.h>
107 #include <linux/kmod.h>
108 #include <linux/nsproxy.h>
110 #undef TTY_DEBUG_HANGUP
111 #ifdef TTY_DEBUG_HANGUP
112 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
114 # define tty_debug_hangup(tty, f, args...) do { } while (0)
117 #define TTY_PARANOIA_CHECK 1
118 #define CHECK_TTY_COUNT 1
120 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
121 .c_iflag = ICRNL | IXON,
122 .c_oflag = OPOST | ONLCR,
123 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
124 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
125 ECHOCTL | ECHOKE | IEXTEN,
129 /* .c_line = N_TTY, */
132 EXPORT_SYMBOL(tty_std_termios);
134 /* This list gets poked at by procfs and various bits of boot up code. This
135 could do with some rationalisation such as pulling the tty proc function
138 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
140 /* Mutex to protect creating and releasing a tty */
141 DEFINE_MUTEX(tty_mutex);
143 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
144 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
145 ssize_t redirected_tty_write(struct file *, const char __user *,
147 static __poll_t tty_poll(struct file *, poll_table *);
148 static int tty_open(struct inode *, struct file *);
149 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
151 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
154 #define tty_compat_ioctl NULL
156 static int __tty_fasync(int fd, struct file *filp, int on);
157 static int tty_fasync(int fd, struct file *filp, int on);
158 static void release_tty(struct tty_struct *tty, int idx);
161 * free_tty_struct - free a disused tty
162 * @tty: tty struct to free
164 * Free the write buffers, tty queue and tty memory itself.
166 * Locking: none. Must be called after tty is definitely unused
169 static void free_tty_struct(struct tty_struct *tty)
171 tty_ldisc_deinit(tty);
172 put_device(tty->dev);
173 kfree(tty->write_buf);
174 tty->magic = 0xDEADDEAD;
178 static inline struct tty_struct *file_tty(struct file *file)
180 return ((struct tty_file_private *)file->private_data)->tty;
183 int tty_alloc_file(struct file *file)
185 struct tty_file_private *priv;
187 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
191 file->private_data = priv;
196 /* Associate a new file with the tty structure */
197 void tty_add_file(struct tty_struct *tty, struct file *file)
199 struct tty_file_private *priv = file->private_data;
204 spin_lock(&tty->files_lock);
205 list_add(&priv->list, &tty->tty_files);
206 spin_unlock(&tty->files_lock);
210 * tty_free_file - free file->private_data
212 * This shall be used only for fail path handling when tty_add_file was not
215 void tty_free_file(struct file *file)
217 struct tty_file_private *priv = file->private_data;
219 file->private_data = NULL;
223 /* Delete file from its tty */
224 static void tty_del_file(struct file *file)
226 struct tty_file_private *priv = file->private_data;
227 struct tty_struct *tty = priv->tty;
229 spin_lock(&tty->files_lock);
230 list_del(&priv->list);
231 spin_unlock(&tty->files_lock);
236 * tty_name - return tty naming
237 * @tty: tty structure
239 * Convert a tty structure into a name. The name reflects the kernel
240 * naming policy and if udev is in use may not reflect user space
245 const char *tty_name(const struct tty_struct *tty)
247 if (!tty) /* Hmm. NULL pointer. That's fun. */
252 EXPORT_SYMBOL(tty_name);
254 const char *tty_driver_name(const struct tty_struct *tty)
256 if (!tty || !tty->driver)
258 return tty->driver->name;
261 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
264 #ifdef TTY_PARANOIA_CHECK
266 pr_warn("(%d:%d): %s: NULL tty\n",
267 imajor(inode), iminor(inode), routine);
270 if (tty->magic != TTY_MAGIC) {
271 pr_warn("(%d:%d): %s: bad magic number\n",
272 imajor(inode), iminor(inode), routine);
279 /* Caller must hold tty_lock */
280 static int check_tty_count(struct tty_struct *tty, const char *routine)
282 #ifdef CHECK_TTY_COUNT
284 int count = 0, kopen_count = 0;
286 spin_lock(&tty->files_lock);
287 list_for_each(p, &tty->tty_files) {
290 spin_unlock(&tty->files_lock);
291 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
292 tty->driver->subtype == PTY_TYPE_SLAVE &&
293 tty->link && tty->link->count)
295 if (tty_port_kopened(tty->port))
297 if (tty->count != (count + kopen_count)) {
298 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
299 routine, tty->count, count, kopen_count);
300 return (count + kopen_count);
307 * get_tty_driver - find device of a tty
308 * @dev_t: device identifier
309 * @index: returns the index of the tty
311 * This routine returns a tty driver structure, given a device number
312 * and also passes back the index number.
314 * Locking: caller must hold tty_mutex
317 static struct tty_driver *get_tty_driver(dev_t device, int *index)
319 struct tty_driver *p;
321 list_for_each_entry(p, &tty_drivers, tty_drivers) {
322 dev_t base = MKDEV(p->major, p->minor_start);
323 if (device < base || device >= base + p->num)
325 *index = device - base;
326 return tty_driver_kref_get(p);
332 * tty_dev_name_to_number - return dev_t for device name
333 * @name: user space name of device under /dev
334 * @number: pointer to dev_t that this function will populate
336 * This function converts device names like ttyS0 or ttyUSB1 into dev_t
337 * like (4, 64) or (188, 1). If no corresponding driver is registered then
338 * the function returns -ENODEV.
340 * Locking: this acquires tty_mutex to protect the tty_drivers list from
341 * being modified while we are traversing it, and makes sure to
342 * release it before exiting.
344 int tty_dev_name_to_number(const char *name, dev_t *number)
346 struct tty_driver *p;
348 int index, prefix_length = 0;
351 for (str = name; *str && !isdigit(*str); str++)
357 ret = kstrtoint(str, 10, &index);
361 prefix_length = str - name;
362 mutex_lock(&tty_mutex);
364 list_for_each_entry(p, &tty_drivers, tty_drivers)
365 if (prefix_length == strlen(p->name) && strncmp(name,
366 p->name, prefix_length) == 0) {
367 if (index < p->num) {
368 *number = MKDEV(p->major, p->minor_start + index);
373 /* if here then driver wasn't found */
376 mutex_unlock(&tty_mutex);
379 EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
381 #ifdef CONFIG_CONSOLE_POLL
384 * tty_find_polling_driver - find device of a polled tty
385 * @name: name string to match
386 * @line: pointer to resulting tty line nr
388 * This routine returns a tty driver structure, given a name
389 * and the condition that the tty driver is capable of polled
392 struct tty_driver *tty_find_polling_driver(char *name, int *line)
394 struct tty_driver *p, *res = NULL;
399 for (str = name; *str; str++)
400 if ((*str >= '0' && *str <= '9') || *str == ',')
406 tty_line = simple_strtoul(str, &str, 10);
408 mutex_lock(&tty_mutex);
409 /* Search through the tty devices to look for a match */
410 list_for_each_entry(p, &tty_drivers, tty_drivers) {
411 if (strncmp(name, p->name, len) != 0)
419 if (tty_line >= 0 && tty_line < p->num && p->ops &&
420 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
421 res = tty_driver_kref_get(p);
426 mutex_unlock(&tty_mutex);
430 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
433 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
434 size_t count, loff_t *ppos)
439 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
440 size_t count, loff_t *ppos)
445 /* No kernel lock held - none needed ;) */
446 static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
448 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
451 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
454 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
457 static long hung_up_tty_compat_ioctl(struct file *file,
458 unsigned int cmd, unsigned long arg)
460 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
463 static int hung_up_tty_fasync(int fd, struct file *file, int on)
468 static void tty_show_fdinfo(struct seq_file *m, struct file *file)
470 struct tty_struct *tty = file_tty(file);
472 if (tty && tty->ops && tty->ops->show_fdinfo)
473 tty->ops->show_fdinfo(tty, m);
476 static const struct file_operations tty_fops = {
481 .unlocked_ioctl = tty_ioctl,
482 .compat_ioctl = tty_compat_ioctl,
484 .release = tty_release,
485 .fasync = tty_fasync,
486 .show_fdinfo = tty_show_fdinfo,
489 static const struct file_operations console_fops = {
492 .write = redirected_tty_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 = 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
545 * This can be called by a "kworker" kernel thread. That is process
546 * synchronous but doesn't hold any locks, so we need to make sure we
547 * have the appropriate locks for what we're doing.
549 * The hangup event clears any pending redirections onto the hung up
550 * device. It ensures future writes will error and it does the needed
551 * line discipline hangup and signal delivery. The tty object itself
556 * redirect lock for undoing redirection
557 * file list lock for manipulating list of ttys
558 * tty_ldiscs_lock from called functions
559 * termios_rwsem resetting termios data
560 * tasklist_lock to walk task list for hangup event
561 * ->siglock to protect ->signal/->sighand
563 static void __tty_hangup(struct tty_struct *tty, int exit_session)
565 struct file *cons_filp = NULL;
566 struct file *filp, *f = NULL;
567 struct tty_file_private *priv;
568 int closecount = 0, n;
575 spin_lock(&redirect_lock);
576 if (redirect && file_tty(redirect) == tty) {
580 spin_unlock(&redirect_lock);
584 if (test_bit(TTY_HUPPED, &tty->flags)) {
589 /* inuse_filps is protected by the single tty lock,
590 this really needs to change if we want to flush the
591 workqueue with the lock held */
592 check_tty_count(tty, "tty_hangup");
594 spin_lock(&tty->files_lock);
595 /* This breaks for file handles being sent over AF_UNIX sockets ? */
596 list_for_each_entry(priv, &tty->tty_files, list) {
598 if (filp->f_op->write == redirected_tty_write)
600 if (filp->f_op->write != tty_write)
603 __tty_fasync(-1, filp, 0); /* can't block */
604 filp->f_op = &hung_up_tty_fops;
606 spin_unlock(&tty->files_lock);
608 refs = tty_signal_session_leader(tty, exit_session);
609 /* Account for the p->signal references we killed */
613 tty_ldisc_hangup(tty, cons_filp != NULL);
615 spin_lock_irq(&tty->ctrl_lock);
616 clear_bit(TTY_THROTTLED, &tty->flags);
617 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
618 put_pid(tty->session);
622 tty->ctrl_status = 0;
623 spin_unlock_irq(&tty->ctrl_lock);
626 * If one of the devices matches a console pointer, we
627 * cannot just call hangup() because that will cause
628 * tty->count and state->count to go out of sync.
629 * So we just call close() the right number of times.
633 for (n = 0; n < closecount; n++)
634 tty->ops->close(tty, cons_filp);
635 } else if (tty->ops->hangup)
636 tty->ops->hangup(tty);
638 * We don't want to have driver/ldisc interactions beyond the ones
639 * we did here. The driver layer expects no calls after ->hangup()
640 * from the ldisc side, which is now guaranteed.
642 set_bit(TTY_HUPPED, &tty->flags);
649 static void do_tty_hangup(struct work_struct *work)
651 struct tty_struct *tty =
652 container_of(work, struct tty_struct, hangup_work);
654 __tty_hangup(tty, 0);
658 * tty_hangup - trigger a hangup event
659 * @tty: tty to hangup
661 * A carrier loss (virtual or otherwise) has occurred on this like
662 * schedule a hangup sequence to run after this event.
665 void tty_hangup(struct tty_struct *tty)
667 tty_debug_hangup(tty, "hangup\n");
668 schedule_work(&tty->hangup_work);
671 EXPORT_SYMBOL(tty_hangup);
674 * tty_vhangup - process vhangup
675 * @tty: tty to hangup
677 * The user has asked via system call for the terminal to be hung up.
678 * We do this synchronously so that when the syscall returns the process
679 * is complete. That guarantee is necessary for security reasons.
682 void tty_vhangup(struct tty_struct *tty)
684 tty_debug_hangup(tty, "vhangup\n");
685 __tty_hangup(tty, 0);
688 EXPORT_SYMBOL(tty_vhangup);
692 * tty_vhangup_self - process vhangup for own ctty
694 * Perform a vhangup on the current controlling tty
697 void tty_vhangup_self(void)
699 struct tty_struct *tty;
701 tty = get_current_tty();
709 * tty_vhangup_session - hangup session leader exit
710 * @tty: tty to hangup
712 * The session leader is exiting and hanging up its controlling terminal.
713 * Every process in the foreground process group is signalled SIGHUP.
715 * We do this synchronously so that when the syscall returns the process
716 * is complete. That guarantee is necessary for security reasons.
719 void tty_vhangup_session(struct tty_struct *tty)
721 tty_debug_hangup(tty, "session hangup\n");
722 __tty_hangup(tty, 1);
726 * tty_hung_up_p - was tty hung up
727 * @filp: file pointer of tty
729 * Return true if the tty has been subject to a vhangup or a carrier
733 int tty_hung_up_p(struct file *filp)
735 return (filp && filp->f_op == &hung_up_tty_fops);
738 EXPORT_SYMBOL(tty_hung_up_p);
741 * stop_tty - propagate flow control
744 * Perform flow control to the driver. May be called
745 * on an already stopped device and will not re-call the driver
748 * This functionality is used by both the line disciplines for
749 * halting incoming flow and by the driver. It may therefore be
750 * called from any context, may be under the tty atomic_write_lock
757 void __stop_tty(struct tty_struct *tty)
766 void stop_tty(struct tty_struct *tty)
770 spin_lock_irqsave(&tty->flow_lock, flags);
772 spin_unlock_irqrestore(&tty->flow_lock, flags);
774 EXPORT_SYMBOL(stop_tty);
777 * start_tty - propagate flow control
780 * Start a tty that has been stopped if at all possible. If this
781 * tty was previous stopped and is now being started, the driver
782 * start method is invoked and the line discipline woken.
788 void __start_tty(struct tty_struct *tty)
790 if (!tty->stopped || tty->flow_stopped)
794 tty->ops->start(tty);
798 void start_tty(struct tty_struct *tty)
802 spin_lock_irqsave(&tty->flow_lock, flags);
804 spin_unlock_irqrestore(&tty->flow_lock, flags);
806 EXPORT_SYMBOL(start_tty);
808 static void tty_update_time(struct timespec *time)
810 unsigned long sec = get_seconds();
813 * We only care if the two values differ in anything other than the
814 * lower three bits (i.e every 8 seconds). If so, then we can update
815 * the time of the tty device, otherwise it could be construded as a
816 * security leak to let userspace know the exact timing of the tty.
818 if ((sec ^ time->tv_sec) & ~7)
823 * tty_read - read method for tty device files
824 * @file: pointer to tty file
826 * @count: size of user buffer
829 * Perform the read system call function on this terminal device. Checks
830 * for hung up devices before calling the line discipline method.
833 * Locks the line discipline internally while needed. Multiple
834 * read calls may be outstanding in parallel.
837 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
841 struct inode *inode = file_inode(file);
842 struct tty_struct *tty = file_tty(file);
843 struct tty_ldisc *ld;
845 if (tty_paranoia_check(tty, inode, "tty_read"))
847 if (!tty || tty_io_error(tty))
850 /* We want to wait for the line discipline to sort out in this
852 ld = tty_ldisc_ref_wait(tty);
854 return hung_up_tty_read(file, buf, count, ppos);
856 i = ld->ops->read(tty, file, buf, count);
862 tty_update_time(&inode->i_atime);
867 static void tty_write_unlock(struct tty_struct *tty)
869 mutex_unlock(&tty->atomic_write_lock);
870 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
873 static int tty_write_lock(struct tty_struct *tty, int ndelay)
875 if (!mutex_trylock(&tty->atomic_write_lock)) {
878 if (mutex_lock_interruptible(&tty->atomic_write_lock))
885 * Split writes up in sane blocksizes to avoid
886 * denial-of-service type attacks
888 static inline ssize_t do_tty_write(
889 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
890 struct tty_struct *tty,
892 const char __user *buf,
895 ssize_t ret, written = 0;
898 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
903 * We chunk up writes into a temporary buffer. This
904 * simplifies low-level drivers immensely, since they
905 * don't have locking issues and user mode accesses.
907 * But if TTY_NO_WRITE_SPLIT is set, we should use a
910 * The default chunk-size is 2kB, because the NTTY
911 * layer has problems with bigger chunks. It will
912 * claim to be able to handle more characters than
915 * FIXME: This can probably go away now except that 64K chunks
916 * are too likely to fail unless switched to vmalloc...
919 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
924 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
925 if (tty->write_cnt < chunk) {
926 unsigned char *buf_chunk;
931 buf_chunk = kmalloc(chunk, GFP_KERNEL);
936 kfree(tty->write_buf);
937 tty->write_cnt = chunk;
938 tty->write_buf = buf_chunk;
941 /* Do the write .. */
947 if (copy_from_user(tty->write_buf, buf, size))
949 ret = write(tty, file, tty->write_buf, size);
958 if (signal_pending(current))
963 tty_update_time(&file_inode(file)->i_mtime);
967 tty_write_unlock(tty);
972 * tty_write_message - write a message to a certain tty, not just the console.
973 * @tty: the destination tty_struct
974 * @msg: the message to write
976 * This is used for messages that need to be redirected to a specific tty.
977 * We don't put it into the syslog queue right now maybe in the future if
980 * We must still hold the BTM and test the CLOSING flag for the moment.
983 void tty_write_message(struct tty_struct *tty, char *msg)
986 mutex_lock(&tty->atomic_write_lock);
988 if (tty->ops->write && tty->count > 0)
989 tty->ops->write(tty, msg, strlen(msg));
991 tty_write_unlock(tty);
998 * tty_write - write method for tty device file
999 * @file: tty file pointer
1000 * @buf: user data to write
1001 * @count: bytes to write
1004 * Write data to a tty device via the line discipline.
1007 * Locks the line discipline as required
1008 * Writes to the tty driver are serialized by the atomic_write_lock
1009 * and are then processed in chunks to the device. The line discipline
1010 * write method will not be invoked in parallel for each device.
1013 static ssize_t tty_write(struct file *file, const char __user *buf,
1014 size_t count, loff_t *ppos)
1016 struct tty_struct *tty = file_tty(file);
1017 struct tty_ldisc *ld;
1020 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1022 if (!tty || !tty->ops->write || tty_io_error(tty))
1024 /* Short term debug to catch buggy drivers */
1025 if (tty->ops->write_room == NULL)
1026 tty_err(tty, "missing write_room method\n");
1027 ld = tty_ldisc_ref_wait(tty);
1029 return hung_up_tty_write(file, buf, count, ppos);
1030 if (!ld->ops->write)
1033 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1034 tty_ldisc_deref(ld);
1038 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1039 size_t count, loff_t *ppos)
1041 struct file *p = NULL;
1043 spin_lock(&redirect_lock);
1045 p = get_file(redirect);
1046 spin_unlock(&redirect_lock);
1050 res = vfs_write(p, buf, count, &p->f_pos);
1054 return tty_write(file, buf, count, ppos);
1058 * tty_send_xchar - send priority character
1060 * Send a high priority character to the tty even if stopped
1062 * Locking: none for xchar method, write ordering for write method.
1065 int tty_send_xchar(struct tty_struct *tty, char ch)
1067 int was_stopped = tty->stopped;
1069 if (tty->ops->send_xchar) {
1070 down_read(&tty->termios_rwsem);
1071 tty->ops->send_xchar(tty, ch);
1072 up_read(&tty->termios_rwsem);
1076 if (tty_write_lock(tty, 0) < 0)
1077 return -ERESTARTSYS;
1079 down_read(&tty->termios_rwsem);
1082 tty->ops->write(tty, &ch, 1);
1085 up_read(&tty->termios_rwsem);
1086 tty_write_unlock(tty);
1090 static char ptychar[] = "pqrstuvwxyzabcde";
1093 * pty_line_name - generate name for a pty
1094 * @driver: the tty driver in use
1095 * @index: the minor number
1096 * @p: output buffer of at least 6 bytes
1098 * Generate a name from a driver reference and write it to the output
1103 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1105 int i = index + driver->name_base;
1106 /* ->name is initialized to "ttyp", but "tty" is expected */
1107 sprintf(p, "%s%c%x",
1108 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1109 ptychar[i >> 4 & 0xf], i & 0xf);
1113 * tty_line_name - generate name for a tty
1114 * @driver: the tty driver in use
1115 * @index: the minor number
1116 * @p: output buffer of at least 7 bytes
1118 * Generate a name from a driver reference and write it to the output
1123 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1125 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1126 return sprintf(p, "%s", driver->name);
1128 return sprintf(p, "%s%d", driver->name,
1129 index + driver->name_base);
1133 * tty_driver_lookup_tty() - find an existing tty, if any
1134 * @driver: the driver for the tty
1135 * @idx: the minor number
1137 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1138 * driver lookup() method returns an error.
1140 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1142 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1143 struct file *file, int idx)
1145 struct tty_struct *tty;
1147 if (driver->ops->lookup)
1149 tty = ERR_PTR(-EIO);
1151 tty = driver->ops->lookup(driver, file, idx);
1153 tty = driver->ttys[idx];
1161 * tty_init_termios - helper for termios setup
1162 * @tty: the tty to set up
1164 * Initialise the termios structures for this tty. Thus runs under
1165 * the tty_mutex currently so we can be relaxed about ordering.
1168 void tty_init_termios(struct tty_struct *tty)
1170 struct ktermios *tp;
1171 int idx = tty->index;
1173 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1174 tty->termios = tty->driver->init_termios;
1176 /* Check for lazy saved data */
1177 tp = tty->driver->termios[idx];
1180 tty->termios.c_line = tty->driver->init_termios.c_line;
1182 tty->termios = tty->driver->init_termios;
1184 /* Compatibility until drivers always set this */
1185 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1186 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1188 EXPORT_SYMBOL_GPL(tty_init_termios);
1190 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1192 tty_init_termios(tty);
1193 tty_driver_kref_get(driver);
1195 driver->ttys[tty->index] = tty;
1198 EXPORT_SYMBOL_GPL(tty_standard_install);
1201 * tty_driver_install_tty() - install a tty entry in the driver
1202 * @driver: the driver for the tty
1205 * Install a tty object into the driver tables. The tty->index field
1206 * will be set by the time this is called. This method is responsible
1207 * for ensuring any need additional structures are allocated and
1210 * Locking: tty_mutex for now
1212 static int tty_driver_install_tty(struct tty_driver *driver,
1213 struct tty_struct *tty)
1215 return driver->ops->install ? driver->ops->install(driver, tty) :
1216 tty_standard_install(driver, tty);
1220 * tty_driver_remove_tty() - remove a tty from the driver tables
1221 * @driver: the driver for the tty
1222 * @idx: the minor number
1224 * Remvoe a tty object from the driver tables. The tty->index field
1225 * will be set by the time this is called.
1227 * Locking: tty_mutex for now
1229 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1231 if (driver->ops->remove)
1232 driver->ops->remove(driver, tty);
1234 driver->ttys[tty->index] = NULL;
1238 * tty_reopen() - fast re-open of an open tty
1239 * @tty - the tty to open
1241 * Return 0 on success, -errno on error.
1242 * Re-opens on master ptys are not allowed and return -EIO.
1244 * Locking: Caller must hold tty_lock
1246 static int tty_reopen(struct tty_struct *tty)
1248 struct tty_driver *driver = tty->driver;
1250 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1251 driver->subtype == PTY_TYPE_MASTER)
1257 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1263 return tty_ldisc_reinit(tty, tty->termios.c_line);
1269 * tty_init_dev - initialise a tty device
1270 * @driver: tty driver we are opening a device on
1271 * @idx: device index
1272 * @ret_tty: returned tty structure
1274 * Prepare a tty device. This may not be a "new" clean device but
1275 * could also be an active device. The pty drivers require special
1276 * handling because of this.
1279 * The function is called under the tty_mutex, which
1280 * protects us from the tty struct or driver itself going away.
1282 * On exit the tty device has the line discipline attached and
1283 * a reference count of 1. If a pair was created for pty/tty use
1284 * and the other was a pty master then it too has a reference count of 1.
1286 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1287 * failed open. The new code protects the open with a mutex, so it's
1288 * really quite straightforward. The mutex locking can probably be
1289 * relaxed for the (most common) case of reopening a tty.
1292 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1294 struct tty_struct *tty;
1298 * First time open is complex, especially for PTY devices.
1299 * This code guarantees that either everything succeeds and the
1300 * TTY is ready for operation, or else the table slots are vacated
1301 * and the allocated memory released. (Except that the termios
1305 if (!try_module_get(driver->owner))
1306 return ERR_PTR(-ENODEV);
1308 tty = alloc_tty_struct(driver, idx);
1311 goto err_module_put;
1315 retval = tty_driver_install_tty(driver, tty);
1320 tty->port = driver->ports[idx];
1322 WARN_RATELIMIT(!tty->port,
1323 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1324 __func__, tty->driver->name);
1326 retval = tty_ldisc_lock(tty, 5 * HZ);
1328 goto err_release_lock;
1329 tty->port->itty = tty;
1332 * Structures all installed ... call the ldisc open routines.
1333 * If we fail here just call release_tty to clean up. No need
1334 * to decrement the use counts, as release_tty doesn't care.
1336 retval = tty_ldisc_setup(tty, tty->link);
1338 goto err_release_tty;
1339 tty_ldisc_unlock(tty);
1340 /* Return the tty locked so that it cannot vanish under the caller */
1345 free_tty_struct(tty);
1347 module_put(driver->owner);
1348 return ERR_PTR(retval);
1350 /* call the tty release_tty routine to clean out this slot */
1352 tty_ldisc_unlock(tty);
1353 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1357 release_tty(tty, idx);
1358 return ERR_PTR(retval);
1361 static void tty_free_termios(struct tty_struct *tty)
1363 struct ktermios *tp;
1364 int idx = tty->index;
1366 /* If the port is going to reset then it has no termios to save */
1367 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1370 /* Stash the termios data */
1371 tp = tty->driver->termios[idx];
1373 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1376 tty->driver->termios[idx] = tp;
1382 * tty_flush_works - flush all works of a tty/pty pair
1383 * @tty: tty device to flush works for (or either end of a pty pair)
1385 * Sync flush all works belonging to @tty (and the 'other' tty).
1387 static void tty_flush_works(struct tty_struct *tty)
1389 flush_work(&tty->SAK_work);
1390 flush_work(&tty->hangup_work);
1392 flush_work(&tty->link->SAK_work);
1393 flush_work(&tty->link->hangup_work);
1398 * release_one_tty - release tty structure memory
1399 * @kref: kref of tty we are obliterating
1401 * Releases memory associated with a tty structure, and clears out the
1402 * driver table slots. This function is called when a device is no longer
1403 * in use. It also gets called when setup of a device fails.
1406 * takes the file list lock internally when working on the list
1407 * of ttys that the driver keeps.
1409 * This method gets called from a work queue so that the driver private
1410 * cleanup ops can sleep (needed for USB at least)
1412 static void release_one_tty(struct work_struct *work)
1414 struct tty_struct *tty =
1415 container_of(work, struct tty_struct, hangup_work);
1416 struct tty_driver *driver = tty->driver;
1417 struct module *owner = driver->owner;
1419 if (tty->ops->cleanup)
1420 tty->ops->cleanup(tty);
1423 tty_driver_kref_put(driver);
1426 spin_lock(&tty->files_lock);
1427 list_del_init(&tty->tty_files);
1428 spin_unlock(&tty->files_lock);
1431 put_pid(tty->session);
1432 free_tty_struct(tty);
1435 static void queue_release_one_tty(struct kref *kref)
1437 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1439 /* The hangup queue is now free so we can reuse it rather than
1440 waste a chunk of memory for each port */
1441 INIT_WORK(&tty->hangup_work, release_one_tty);
1442 schedule_work(&tty->hangup_work);
1446 * tty_kref_put - release a tty kref
1449 * Release a reference to a tty device and if need be let the kref
1450 * layer destruct the object for us
1453 void tty_kref_put(struct tty_struct *tty)
1456 kref_put(&tty->kref, queue_release_one_tty);
1458 EXPORT_SYMBOL(tty_kref_put);
1461 * release_tty - release tty structure memory
1463 * Release both @tty and a possible linked partner (think pty pair),
1464 * and decrement the refcount of the backing module.
1468 * takes the file list lock internally when working on the list
1469 * of ttys that the driver keeps.
1472 static void release_tty(struct tty_struct *tty, int idx)
1474 /* This should always be true but check for the moment */
1475 WARN_ON(tty->index != idx);
1476 WARN_ON(!mutex_is_locked(&tty_mutex));
1477 if (tty->ops->shutdown)
1478 tty->ops->shutdown(tty);
1479 tty_free_termios(tty);
1480 tty_driver_remove_tty(tty->driver, tty);
1481 tty->port->itty = NULL;
1483 tty->link->port->itty = NULL;
1484 tty_buffer_cancel_work(tty->port);
1486 tty_buffer_cancel_work(tty->link->port);
1488 tty_kref_put(tty->link);
1493 * tty_release_checks - check a tty before real release
1494 * @tty: tty to check
1495 * @o_tty: link of @tty (if any)
1496 * @idx: index of the tty
1498 * Performs some paranoid checking before true release of the @tty.
1499 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1501 static int tty_release_checks(struct tty_struct *tty, int idx)
1503 #ifdef TTY_PARANOIA_CHECK
1504 if (idx < 0 || idx >= tty->driver->num) {
1505 tty_debug(tty, "bad idx %d\n", idx);
1509 /* not much to check for devpts */
1510 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1513 if (tty != tty->driver->ttys[idx]) {
1514 tty_debug(tty, "bad driver table[%d] = %p\n",
1515 idx, tty->driver->ttys[idx]);
1518 if (tty->driver->other) {
1519 struct tty_struct *o_tty = tty->link;
1521 if (o_tty != tty->driver->other->ttys[idx]) {
1522 tty_debug(tty, "bad other table[%d] = %p\n",
1523 idx, tty->driver->other->ttys[idx]);
1526 if (o_tty->link != tty) {
1527 tty_debug(tty, "bad link = %p\n", o_tty->link);
1536 * tty_kclose - closes tty opened by tty_kopen
1539 * Performs the final steps to release and free a tty device. It is the
1540 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1541 * flag on tty->port.
1543 void tty_kclose(struct tty_struct *tty)
1546 * Ask the line discipline code to release its structures
1548 tty_ldisc_release(tty);
1550 /* Wait for pending work before tty destruction commmences */
1551 tty_flush_works(tty);
1553 tty_debug_hangup(tty, "freeing structure\n");
1555 * The release_tty function takes care of the details of clearing
1556 * the slots and preserving the termios structure. The tty_unlock_pair
1557 * should be safe as we keep a kref while the tty is locked (so the
1558 * unlock never unlocks a freed tty).
1560 mutex_lock(&tty_mutex);
1561 tty_port_set_kopened(tty->port, 0);
1562 release_tty(tty, tty->index);
1563 mutex_unlock(&tty_mutex);
1565 EXPORT_SYMBOL_GPL(tty_kclose);
1568 * tty_release_struct - release a tty struct
1570 * @idx: index of the tty
1572 * Performs the final steps to release and free a tty device. It is
1573 * roughly the reverse of tty_init_dev.
1575 void tty_release_struct(struct tty_struct *tty, int idx)
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 release_tty(tty, idx);
1594 mutex_unlock(&tty_mutex);
1596 EXPORT_SYMBOL_GPL(tty_release_struct);
1599 * tty_release - vfs callback for close
1600 * @inode: inode of tty
1601 * @filp: file pointer for handle to tty
1603 * Called the last time each file handle is closed that references
1604 * this tty. There may however be several such references.
1607 * Takes bkl. See tty_release_dev
1609 * Even releasing the tty structures is a tricky business.. We have
1610 * to be very careful that the structures are all released at the
1611 * same time, as interrupts might otherwise get the wrong pointers.
1613 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1614 * lead to double frees or releasing memory still in use.
1617 int tty_release(struct inode *inode, struct file *filp)
1619 struct tty_struct *tty = file_tty(filp);
1620 struct tty_struct *o_tty = NULL;
1621 int do_sleep, final;
1626 if (tty_paranoia_check(tty, inode, __func__))
1630 check_tty_count(tty, __func__);
1632 __tty_fasync(-1, filp, 0);
1635 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1636 tty->driver->subtype == PTY_TYPE_MASTER)
1639 if (tty_release_checks(tty, idx)) {
1644 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1646 if (tty->ops->close)
1647 tty->ops->close(tty, filp);
1649 /* If tty is pty master, lock the slave pty (stable lock order) */
1650 tty_lock_slave(o_tty);
1653 * Sanity check: if tty->count is going to zero, there shouldn't be
1654 * any waiters on tty->read_wait or tty->write_wait. We test the
1655 * wait queues and kick everyone out _before_ actually starting to
1656 * close. This ensures that we won't block while releasing the tty
1659 * The test for the o_tty closing is necessary, since the master and
1660 * slave sides may close in any order. If the slave side closes out
1661 * first, its count will be one, since the master side holds an open.
1662 * Thus this test wouldn't be triggered at the time the slave closed,
1668 if (tty->count <= 1) {
1669 if (waitqueue_active(&tty->read_wait)) {
1670 wake_up_poll(&tty->read_wait, EPOLLIN);
1673 if (waitqueue_active(&tty->write_wait)) {
1674 wake_up_poll(&tty->write_wait, EPOLLOUT);
1678 if (o_tty && o_tty->count <= 1) {
1679 if (waitqueue_active(&o_tty->read_wait)) {
1680 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1683 if (waitqueue_active(&o_tty->write_wait)) {
1684 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1693 tty_warn(tty, "read/write wait queue active!\n");
1695 schedule_timeout_killable(timeout);
1696 if (timeout < 120 * HZ)
1697 timeout = 2 * timeout + 1;
1699 timeout = MAX_SCHEDULE_TIMEOUT;
1703 if (--o_tty->count < 0) {
1704 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1708 if (--tty->count < 0) {
1709 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1714 * We've decremented tty->count, so we need to remove this file
1715 * descriptor off the tty->tty_files list; this serves two
1717 * - check_tty_count sees the correct number of file descriptors
1718 * associated with this tty.
1719 * - do_tty_hangup no longer sees this file descriptor as
1720 * something that needs to be handled for hangups.
1725 * Perform some housekeeping before deciding whether to return.
1727 * If _either_ side is closing, make sure there aren't any
1728 * processes that still think tty or o_tty is their controlling
1732 read_lock(&tasklist_lock);
1733 session_clear_tty(tty->session);
1735 session_clear_tty(o_tty->session);
1736 read_unlock(&tasklist_lock);
1739 /* check whether both sides are closing ... */
1740 final = !tty->count && !(o_tty && o_tty->count);
1742 tty_unlock_slave(o_tty);
1745 /* At this point, the tty->count == 0 should ensure a dead tty
1746 cannot be re-opened by a racing opener */
1751 tty_debug_hangup(tty, "final close\n");
1753 tty_release_struct(tty, idx);
1758 * tty_open_current_tty - get locked tty of current task
1759 * @device: device number
1760 * @filp: file pointer to tty
1761 * @return: locked tty of the current task iff @device is /dev/tty
1763 * Performs a re-open of the current task's controlling tty.
1765 * We cannot return driver and index like for the other nodes because
1766 * devpts will not work then. It expects inodes to be from devpts FS.
1768 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1770 struct tty_struct *tty;
1773 if (device != MKDEV(TTYAUX_MAJOR, 0))
1776 tty = get_current_tty();
1778 return ERR_PTR(-ENXIO);
1780 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1783 tty_kref_put(tty); /* safe to drop the kref now */
1785 retval = tty_reopen(tty);
1788 tty = ERR_PTR(retval);
1794 * tty_lookup_driver - lookup a tty driver for a given device file
1795 * @device: device number
1796 * @filp: file pointer to tty
1797 * @index: index for the device in the @return driver
1798 * @return: driver for this inode (with increased refcount)
1800 * If @return is not erroneous, the caller is responsible to decrement the
1801 * refcount by tty_driver_kref_put.
1803 * Locking: tty_mutex protects get_tty_driver
1805 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1808 struct tty_driver *driver;
1812 case MKDEV(TTY_MAJOR, 0): {
1813 extern struct tty_driver *console_driver;
1814 driver = tty_driver_kref_get(console_driver);
1815 *index = fg_console;
1819 case MKDEV(TTYAUX_MAJOR, 1): {
1820 struct tty_driver *console_driver = console_device(index);
1821 if (console_driver) {
1822 driver = tty_driver_kref_get(console_driver);
1823 if (driver && filp) {
1824 /* Don't let /dev/console block */
1825 filp->f_flags |= O_NONBLOCK;
1829 return ERR_PTR(-ENODEV);
1832 driver = get_tty_driver(device, index);
1834 return ERR_PTR(-ENODEV);
1841 * tty_kopen - open a tty device for kernel
1842 * @device: dev_t of device to open
1844 * Opens tty exclusively for kernel. Performs the driver lookup,
1845 * makes sure it's not already opened and performs the first-time
1846 * tty initialization.
1848 * Returns the locked initialized &tty_struct
1850 * Claims the global tty_mutex to serialize:
1851 * - concurrent first-time tty initialization
1852 * - concurrent tty driver removal w/ lookup
1853 * - concurrent tty removal from driver table
1855 struct tty_struct *tty_kopen(dev_t device)
1857 struct tty_struct *tty;
1858 struct tty_driver *driver = NULL;
1861 mutex_lock(&tty_mutex);
1862 driver = tty_lookup_driver(device, NULL, &index);
1863 if (IS_ERR(driver)) {
1864 mutex_unlock(&tty_mutex);
1865 return ERR_CAST(driver);
1868 /* check whether we're reopening an existing tty */
1869 tty = tty_driver_lookup_tty(driver, NULL, index);
1874 /* drop kref from tty_driver_lookup_tty() */
1876 tty = ERR_PTR(-EBUSY);
1877 } else { /* tty_init_dev returns tty with the tty_lock held */
1878 tty = tty_init_dev(driver, index);
1881 tty_port_set_kopened(tty->port, 1);
1884 mutex_unlock(&tty_mutex);
1885 tty_driver_kref_put(driver);
1888 EXPORT_SYMBOL_GPL(tty_kopen);
1891 * tty_open_by_driver - open a tty device
1892 * @device: dev_t of device to open
1893 * @inode: inode of device file
1894 * @filp: file pointer to tty
1896 * Performs the driver lookup, checks for a reopen, or otherwise
1897 * performs the first-time tty initialization.
1899 * Returns the locked initialized or re-opened &tty_struct
1901 * Claims the global tty_mutex to serialize:
1902 * - concurrent first-time tty initialization
1903 * - concurrent tty driver removal w/ lookup
1904 * - concurrent tty removal from driver table
1906 static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
1909 struct tty_struct *tty;
1910 struct tty_driver *driver = NULL;
1914 mutex_lock(&tty_mutex);
1915 driver = tty_lookup_driver(device, filp, &index);
1916 if (IS_ERR(driver)) {
1917 mutex_unlock(&tty_mutex);
1918 return ERR_CAST(driver);
1921 /* check whether we're reopening an existing tty */
1922 tty = tty_driver_lookup_tty(driver, filp, index);
1924 mutex_unlock(&tty_mutex);
1929 if (tty_port_kopened(tty->port)) {
1931 mutex_unlock(&tty_mutex);
1932 tty = ERR_PTR(-EBUSY);
1935 mutex_unlock(&tty_mutex);
1936 retval = tty_lock_interruptible(tty);
1937 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
1939 if (retval == -EINTR)
1940 retval = -ERESTARTSYS;
1941 tty = ERR_PTR(retval);
1944 retval = tty_reopen(tty);
1947 tty = ERR_PTR(retval);
1949 } else { /* Returns with the tty_lock held for now */
1950 tty = tty_init_dev(driver, index);
1951 mutex_unlock(&tty_mutex);
1954 tty_driver_kref_put(driver);
1959 * tty_open - open a tty device
1960 * @inode: inode of device file
1961 * @filp: file pointer to tty
1963 * tty_open and tty_release keep up the tty count that contains the
1964 * number of opens done on a tty. We cannot use the inode-count, as
1965 * different inodes might point to the same tty.
1967 * Open-counting is needed for pty masters, as well as for keeping
1968 * track of serial lines: DTR is dropped when the last close happens.
1969 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1971 * The termios state of a pty is reset on first open so that
1972 * settings don't persist across reuse.
1974 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1975 * tty->count should protect the rest.
1976 * ->siglock protects ->signal/->sighand
1978 * Note: the tty_unlock/lock cases without a ref are only safe due to
1982 static int tty_open(struct inode *inode, struct file *filp)
1984 struct tty_struct *tty;
1986 dev_t device = inode->i_rdev;
1987 unsigned saved_flags = filp->f_flags;
1989 nonseekable_open(inode, filp);
1992 retval = tty_alloc_file(filp);
1996 tty = tty_open_current_tty(device, filp);
1998 tty = tty_open_by_driver(device, inode, filp);
2001 tty_free_file(filp);
2002 retval = PTR_ERR(tty);
2003 if (retval != -EAGAIN || signal_pending(current))
2009 tty_add_file(tty, filp);
2011 check_tty_count(tty, __func__);
2012 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2015 retval = tty->ops->open(tty, filp);
2018 filp->f_flags = saved_flags;
2021 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2023 tty_unlock(tty); /* need to call tty_release without BTM */
2024 tty_release(inode, filp);
2025 if (retval != -ERESTARTSYS)
2028 if (signal_pending(current))
2033 * Need to reset f_op in case a hangup happened.
2035 if (tty_hung_up_p(filp))
2036 filp->f_op = &tty_fops;
2039 clear_bit(TTY_HUPPED, &tty->flags);
2041 noctty = (filp->f_flags & O_NOCTTY) ||
2042 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2043 device == MKDEV(TTYAUX_MAJOR, 1) ||
2044 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2045 tty->driver->subtype == PTY_TYPE_MASTER);
2047 tty_open_proc_set_tty(filp, tty);
2055 * tty_poll - check tty status
2056 * @filp: file being polled
2057 * @wait: poll wait structures to update
2059 * Call the line discipline polling method to obtain the poll
2060 * status of the device.
2062 * Locking: locks called line discipline but ldisc poll method
2063 * may be re-entered freely by other callers.
2066 static __poll_t tty_poll(struct file *filp, poll_table *wait)
2068 struct tty_struct *tty = file_tty(filp);
2069 struct tty_ldisc *ld;
2072 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2075 ld = tty_ldisc_ref_wait(tty);
2077 return hung_up_tty_poll(filp, wait);
2079 ret = ld->ops->poll(tty, filp, wait);
2080 tty_ldisc_deref(ld);
2084 static int __tty_fasync(int fd, struct file *filp, int on)
2086 struct tty_struct *tty = file_tty(filp);
2087 unsigned long flags;
2090 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2093 retval = fasync_helper(fd, filp, on, &tty->fasync);
2101 spin_lock_irqsave(&tty->ctrl_lock, flags);
2104 type = PIDTYPE_PGID;
2106 pid = task_pid(current);
2110 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2111 __f_setown(filp, pid, type, 0);
2119 static int tty_fasync(int fd, struct file *filp, int on)
2121 struct tty_struct *tty = file_tty(filp);
2122 int retval = -ENOTTY;
2125 if (!tty_hung_up_p(filp))
2126 retval = __tty_fasync(fd, filp, on);
2133 * tiocsti - fake input character
2134 * @tty: tty to fake input into
2135 * @p: pointer to character
2137 * Fake input to a tty device. Does the necessary locking and
2140 * FIXME: does not honour flow control ??
2143 * Called functions take tty_ldiscs_lock
2144 * current->signal->tty check is safe without locks
2146 * FIXME: may race normal receive processing
2149 static int tiocsti(struct tty_struct *tty, char __user *p)
2152 struct tty_ldisc *ld;
2154 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2156 if (get_user(ch, p))
2158 tty_audit_tiocsti(tty, ch);
2159 ld = tty_ldisc_ref_wait(tty);
2162 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2163 tty_ldisc_deref(ld);
2168 * tiocgwinsz - implement window query ioctl
2170 * @arg: user buffer for result
2172 * Copies the kernel idea of the window size into the user buffer.
2174 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2178 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2182 mutex_lock(&tty->winsize_mutex);
2183 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2184 mutex_unlock(&tty->winsize_mutex);
2186 return err ? -EFAULT: 0;
2190 * tty_do_resize - resize event
2191 * @tty: tty being resized
2192 * @rows: rows (character)
2193 * @cols: cols (character)
2195 * Update the termios variables and send the necessary signals to
2196 * peform a terminal resize correctly
2199 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2204 mutex_lock(&tty->winsize_mutex);
2205 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2208 /* Signal the foreground process group */
2209 pgrp = tty_get_pgrp(tty);
2211 kill_pgrp(pgrp, SIGWINCH, 1);
2216 mutex_unlock(&tty->winsize_mutex);
2219 EXPORT_SYMBOL(tty_do_resize);
2222 * tiocswinsz - implement window size set ioctl
2223 * @tty; tty side of tty
2224 * @arg: user buffer for result
2226 * Copies the user idea of the window size to the kernel. Traditionally
2227 * this is just advisory information but for the Linux console it
2228 * actually has driver level meaning and triggers a VC resize.
2231 * Driver dependent. The default do_resize method takes the
2232 * tty termios mutex and ctrl_lock. The console takes its own lock
2233 * then calls into the default method.
2236 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2238 struct winsize tmp_ws;
2239 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2242 if (tty->ops->resize)
2243 return tty->ops->resize(tty, &tmp_ws);
2245 return tty_do_resize(tty, &tmp_ws);
2249 * tioccons - allow admin to move logical console
2250 * @file: the file to become console
2252 * Allow the administrator to move the redirected console device
2254 * Locking: uses redirect_lock to guard the redirect information
2257 static int tioccons(struct file *file)
2259 if (!capable(CAP_SYS_ADMIN))
2261 if (file->f_op->write == redirected_tty_write) {
2263 spin_lock(&redirect_lock);
2266 spin_unlock(&redirect_lock);
2271 spin_lock(&redirect_lock);
2273 spin_unlock(&redirect_lock);
2276 redirect = get_file(file);
2277 spin_unlock(&redirect_lock);
2282 * fionbio - non blocking ioctl
2283 * @file: file to set blocking value
2284 * @p: user parameter
2286 * Historical tty interfaces had a blocking control ioctl before
2287 * the generic functionality existed. This piece of history is preserved
2288 * in the expected tty API of posix OS's.
2290 * Locking: none, the open file handle ensures it won't go away.
2293 static int fionbio(struct file *file, int __user *p)
2297 if (get_user(nonblock, p))
2300 spin_lock(&file->f_lock);
2302 file->f_flags |= O_NONBLOCK;
2304 file->f_flags &= ~O_NONBLOCK;
2305 spin_unlock(&file->f_lock);
2310 * tiocsetd - set line discipline
2312 * @p: pointer to user data
2314 * Set the line discipline according to user request.
2316 * Locking: see tty_set_ldisc, this function is just a helper
2319 static int tiocsetd(struct tty_struct *tty, int __user *p)
2324 if (get_user(disc, p))
2327 ret = tty_set_ldisc(tty, disc);
2333 * tiocgetd - get line discipline
2335 * @p: pointer to user data
2337 * Retrieves the line discipline id directly from the ldisc.
2339 * Locking: waits for ldisc reference (in case the line discipline
2340 * is changing or the tty is being hungup)
2343 static int tiocgetd(struct tty_struct *tty, int __user *p)
2345 struct tty_ldisc *ld;
2348 ld = tty_ldisc_ref_wait(tty);
2351 ret = put_user(ld->ops->num, p);
2352 tty_ldisc_deref(ld);
2357 * send_break - performed time break
2358 * @tty: device to break on
2359 * @duration: timeout in mS
2361 * Perform a timed break on hardware that lacks its own driver level
2362 * timed break functionality.
2365 * atomic_write_lock serializes
2369 static int send_break(struct tty_struct *tty, unsigned int duration)
2373 if (tty->ops->break_ctl == NULL)
2376 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2377 retval = tty->ops->break_ctl(tty, duration);
2379 /* Do the work ourselves */
2380 if (tty_write_lock(tty, 0) < 0)
2382 retval = tty->ops->break_ctl(tty, -1);
2385 if (!signal_pending(current))
2386 msleep_interruptible(duration);
2387 retval = tty->ops->break_ctl(tty, 0);
2389 tty_write_unlock(tty);
2390 if (signal_pending(current))
2397 * tty_tiocmget - get modem status
2399 * @file: user file pointer
2400 * @p: pointer to result
2402 * Obtain the modem status bits from the tty driver if the feature
2403 * is supported. Return -EINVAL if it is not available.
2405 * Locking: none (up to the driver)
2408 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2410 int retval = -EINVAL;
2412 if (tty->ops->tiocmget) {
2413 retval = tty->ops->tiocmget(tty);
2416 retval = put_user(retval, p);
2422 * tty_tiocmset - set modem status
2424 * @cmd: command - clear bits, set bits or set all
2425 * @p: pointer to desired bits
2427 * Set the modem status bits from the tty driver if the feature
2428 * is supported. Return -EINVAL if it is not available.
2430 * Locking: none (up to the driver)
2433 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2437 unsigned int set, clear, val;
2439 if (tty->ops->tiocmset == NULL)
2442 retval = get_user(val, p);
2458 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2459 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2460 return tty->ops->tiocmset(tty, set, clear);
2463 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2465 int retval = -EINVAL;
2466 struct serial_icounter_struct icount;
2467 memset(&icount, 0, sizeof(icount));
2468 if (tty->ops->get_icount)
2469 retval = tty->ops->get_icount(tty, &icount);
2472 if (copy_to_user(arg, &icount, sizeof(icount)))
2477 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2479 static DEFINE_RATELIMIT_STATE(depr_flags,
2480 DEFAULT_RATELIMIT_INTERVAL,
2481 DEFAULT_RATELIMIT_BURST);
2482 char comm[TASK_COMM_LEN];
2485 if (get_user(flags, &ss->flags))
2488 flags &= ASYNC_DEPRECATED;
2490 if (flags && __ratelimit(&depr_flags))
2491 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2492 __func__, get_task_comm(comm, current), flags);
2496 * if pty, return the slave side (real_tty)
2497 * otherwise, return self
2499 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2501 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2502 tty->driver->subtype == PTY_TYPE_MASTER)
2508 * Split this up, as gcc can choke on it otherwise..
2510 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2512 struct tty_struct *tty = file_tty(file);
2513 struct tty_struct *real_tty;
2514 void __user *p = (void __user *)arg;
2516 struct tty_ldisc *ld;
2518 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2521 real_tty = tty_pair_get_tty(tty);
2524 * Factor out some common prep work
2532 retval = tty_check_change(tty);
2535 if (cmd != TIOCCBRK) {
2536 tty_wait_until_sent(tty, 0);
2537 if (signal_pending(current))
2548 return tiocsti(tty, p);
2550 return tiocgwinsz(real_tty, p);
2552 return tiocswinsz(real_tty, p);
2554 return real_tty != tty ? -EINVAL : tioccons(file);
2556 return fionbio(file, p);
2558 set_bit(TTY_EXCLUSIVE, &tty->flags);
2561 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2565 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2566 return put_user(excl, (int __user *)p);
2569 return tiocgetd(tty, p);
2571 return tiocsetd(tty, p);
2573 if (!capable(CAP_SYS_ADMIN))
2579 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2580 return put_user(ret, (unsigned int __user *)p);
2585 case TIOCSBRK: /* Turn break on, unconditionally */
2586 if (tty->ops->break_ctl)
2587 return tty->ops->break_ctl(tty, -1);
2589 case TIOCCBRK: /* Turn break off, unconditionally */
2590 if (tty->ops->break_ctl)
2591 return tty->ops->break_ctl(tty, 0);
2593 case TCSBRK: /* SVID version: non-zero arg --> no break */
2594 /* non-zero arg means wait for all output data
2595 * to be sent (performed above) but don't send break.
2596 * This is used by the tcdrain() termios function.
2599 return send_break(tty, 250);
2601 case TCSBRKP: /* support for POSIX tcsendbreak() */
2602 return send_break(tty, arg ? arg*100 : 250);
2605 return tty_tiocmget(tty, p);
2609 return tty_tiocmset(tty, cmd, p);
2611 retval = tty_tiocgicount(tty, p);
2612 /* For the moment allow fall through to the old method */
2613 if (retval != -EINVAL)
2620 /* flush tty buffer and allow ldisc to process ioctl */
2621 tty_buffer_flush(tty, NULL);
2626 tty_warn_deprecated_flags(p);
2629 /* Special because the struct file is needed */
2630 return ptm_open_peer(file, tty, (int)arg);
2632 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2633 if (retval != -ENOIOCTLCMD)
2636 if (tty->ops->ioctl) {
2637 retval = tty->ops->ioctl(tty, cmd, arg);
2638 if (retval != -ENOIOCTLCMD)
2641 ld = tty_ldisc_ref_wait(tty);
2643 return hung_up_tty_ioctl(file, cmd, arg);
2645 if (ld->ops->ioctl) {
2646 retval = ld->ops->ioctl(tty, file, cmd, arg);
2647 if (retval == -ENOIOCTLCMD)
2650 tty_ldisc_deref(ld);
2654 #ifdef CONFIG_COMPAT
2655 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2658 struct tty_struct *tty = file_tty(file);
2659 struct tty_ldisc *ld;
2660 int retval = -ENOIOCTLCMD;
2662 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2665 if (tty->ops->compat_ioctl) {
2666 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2667 if (retval != -ENOIOCTLCMD)
2671 ld = tty_ldisc_ref_wait(tty);
2673 return hung_up_tty_compat_ioctl(file, cmd, arg);
2674 if (ld->ops->compat_ioctl)
2675 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2677 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2678 tty_ldisc_deref(ld);
2684 static int this_tty(const void *t, struct file *file, unsigned fd)
2686 if (likely(file->f_op->read != tty_read))
2688 return file_tty(file) != t ? 0 : fd + 1;
2692 * This implements the "Secure Attention Key" --- the idea is to
2693 * prevent trojan horses by killing all processes associated with this
2694 * tty when the user hits the "Secure Attention Key". Required for
2695 * super-paranoid applications --- see the Orange Book for more details.
2697 * This code could be nicer; ideally it should send a HUP, wait a few
2698 * seconds, then send a INT, and then a KILL signal. But you then
2699 * have to coordinate with the init process, since all processes associated
2700 * with the current tty must be dead before the new getty is allowed
2703 * Now, if it would be correct ;-/ The current code has a nasty hole -
2704 * it doesn't catch files in flight. We may send the descriptor to ourselves
2705 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2707 * Nasty bug: do_SAK is being called in interrupt context. This can
2708 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2710 void __do_SAK(struct tty_struct *tty)
2715 struct task_struct *g, *p;
2716 struct pid *session;
2721 session = tty->session;
2723 tty_ldisc_flush(tty);
2725 tty_driver_flush_buffer(tty);
2727 read_lock(&tasklist_lock);
2728 /* Kill the entire session */
2729 do_each_pid_task(session, PIDTYPE_SID, p) {
2730 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
2731 task_pid_nr(p), p->comm);
2732 send_sig(SIGKILL, p, 1);
2733 } while_each_pid_task(session, PIDTYPE_SID, p);
2735 /* Now kill any processes that happen to have the tty open */
2736 do_each_thread(g, p) {
2737 if (p->signal->tty == tty) {
2738 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
2739 task_pid_nr(p), p->comm);
2740 send_sig(SIGKILL, p, 1);
2744 i = iterate_fd(p->files, 0, this_tty, tty);
2746 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
2747 task_pid_nr(p), p->comm, i - 1);
2748 force_sig(SIGKILL, p);
2751 } while_each_thread(g, p);
2752 read_unlock(&tasklist_lock);
2756 static void do_SAK_work(struct work_struct *work)
2758 struct tty_struct *tty =
2759 container_of(work, struct tty_struct, SAK_work);
2764 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2765 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2766 * the values which we write to it will be identical to the values which it
2767 * already has. --akpm
2769 void do_SAK(struct tty_struct *tty)
2773 schedule_work(&tty->SAK_work);
2776 EXPORT_SYMBOL(do_SAK);
2778 static int dev_match_devt(struct device *dev, const void *data)
2780 const dev_t *devt = data;
2781 return dev->devt == *devt;
2784 /* Must put_device() after it's unused! */
2785 static struct device *tty_get_device(struct tty_struct *tty)
2787 dev_t devt = tty_devnum(tty);
2788 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2795 * This subroutine allocates and initializes a tty structure.
2797 * Locking: none - tty in question is not exposed at this point
2800 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
2802 struct tty_struct *tty;
2804 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
2808 kref_init(&tty->kref);
2809 tty->magic = TTY_MAGIC;
2810 tty_ldisc_init(tty);
2811 tty->session = NULL;
2813 mutex_init(&tty->legacy_mutex);
2814 mutex_init(&tty->throttle_mutex);
2815 init_rwsem(&tty->termios_rwsem);
2816 mutex_init(&tty->winsize_mutex);
2817 init_ldsem(&tty->ldisc_sem);
2818 init_waitqueue_head(&tty->write_wait);
2819 init_waitqueue_head(&tty->read_wait);
2820 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2821 mutex_init(&tty->atomic_write_lock);
2822 spin_lock_init(&tty->ctrl_lock);
2823 spin_lock_init(&tty->flow_lock);
2824 spin_lock_init(&tty->files_lock);
2825 INIT_LIST_HEAD(&tty->tty_files);
2826 INIT_WORK(&tty->SAK_work, do_SAK_work);
2828 tty->driver = driver;
2829 tty->ops = driver->ops;
2831 tty_line_name(driver, idx, tty->name);
2832 tty->dev = tty_get_device(tty);
2838 * tty_put_char - write one character to a tty
2842 * Write one byte to the tty using the provided put_char method
2843 * if present. Returns the number of characters successfully output.
2845 * Note: the specific put_char operation in the driver layer may go
2846 * away soon. Don't call it directly, use this method
2849 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2851 if (tty->ops->put_char)
2852 return tty->ops->put_char(tty, ch);
2853 return tty->ops->write(tty, &ch, 1);
2855 EXPORT_SYMBOL_GPL(tty_put_char);
2857 struct class *tty_class;
2859 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
2860 unsigned int index, unsigned int count)
2864 /* init here, since reused cdevs cause crashes */
2865 driver->cdevs[index] = cdev_alloc();
2866 if (!driver->cdevs[index])
2868 driver->cdevs[index]->ops = &tty_fops;
2869 driver->cdevs[index]->owner = driver->owner;
2870 err = cdev_add(driver->cdevs[index], dev, count);
2872 kobject_put(&driver->cdevs[index]->kobj);
2877 * tty_register_device - register a tty device
2878 * @driver: the tty driver that describes the tty device
2879 * @index: the index in the tty driver for this tty device
2880 * @device: a struct device that is associated with this tty device.
2881 * This field is optional, if there is no known struct device
2882 * for this tty device it can be set to NULL safely.
2884 * Returns a pointer to the struct device for this tty device
2885 * (or ERR_PTR(-EFOO) on error).
2887 * This call is required to be made to register an individual tty device
2888 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2889 * that bit is not set, this function should not be called by a tty
2895 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2896 struct device *device)
2898 return tty_register_device_attr(driver, index, device, NULL, NULL);
2900 EXPORT_SYMBOL(tty_register_device);
2902 static void tty_device_create_release(struct device *dev)
2904 dev_dbg(dev, "releasing...\n");
2909 * tty_register_device_attr - register a tty device
2910 * @driver: the tty driver that describes the tty device
2911 * @index: the index in the tty driver for this tty device
2912 * @device: a struct device that is associated with this tty device.
2913 * This field is optional, if there is no known struct device
2914 * for this tty device it can be set to NULL safely.
2915 * @drvdata: Driver data to be set to device.
2916 * @attr_grp: Attribute group to be set on device.
2918 * Returns a pointer to the struct device for this tty device
2919 * (or ERR_PTR(-EFOO) on error).
2921 * This call is required to be made to register an individual tty device
2922 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2923 * that bit is not set, this function should not be called by a tty
2928 struct device *tty_register_device_attr(struct tty_driver *driver,
2929 unsigned index, struct device *device,
2931 const struct attribute_group **attr_grp)
2934 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
2935 struct ktermios *tp;
2939 if (index >= driver->num) {
2940 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
2941 driver->name, index);
2942 return ERR_PTR(-EINVAL);
2945 if (driver->type == TTY_DRIVER_TYPE_PTY)
2946 pty_line_name(driver, index, name);
2948 tty_line_name(driver, index, name);
2950 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2952 return ERR_PTR(-ENOMEM);
2955 dev->class = tty_class;
2956 dev->parent = device;
2957 dev->release = tty_device_create_release;
2958 dev_set_name(dev, "%s", name);
2959 dev->groups = attr_grp;
2960 dev_set_drvdata(dev, drvdata);
2962 dev_set_uevent_suppress(dev, 1);
2964 retval = device_register(dev);
2968 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
2970 * Free any saved termios data so that the termios state is
2971 * reset when reusing a minor number.
2973 tp = driver->termios[index];
2975 driver->termios[index] = NULL;
2979 retval = tty_cdev_add(driver, devt, index, 1);
2984 dev_set_uevent_suppress(dev, 0);
2985 kobject_uevent(&dev->kobj, KOBJ_ADD);
2994 return ERR_PTR(retval);
2996 EXPORT_SYMBOL_GPL(tty_register_device_attr);
2999 * tty_unregister_device - unregister a tty device
3000 * @driver: the tty driver that describes the tty device
3001 * @index: the index in the tty driver for this tty device
3003 * If a tty device is registered with a call to tty_register_device() then
3004 * this function must be called when the tty device is gone.
3009 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3011 device_destroy(tty_class,
3012 MKDEV(driver->major, driver->minor_start) + index);
3013 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3014 cdev_del(driver->cdevs[index]);
3015 driver->cdevs[index] = NULL;
3018 EXPORT_SYMBOL(tty_unregister_device);
3021 * __tty_alloc_driver -- allocate tty driver
3022 * @lines: count of lines this driver can handle at most
3023 * @owner: module which is responsible for this driver
3024 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3026 * This should not be called directly, some of the provided macros should be
3027 * used instead. Use IS_ERR and friends on @retval.
3029 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3030 unsigned long flags)
3032 struct tty_driver *driver;
3033 unsigned int cdevs = 1;
3036 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3037 return ERR_PTR(-EINVAL);
3039 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3041 return ERR_PTR(-ENOMEM);
3043 kref_init(&driver->kref);
3044 driver->magic = TTY_DRIVER_MAGIC;
3045 driver->num = lines;
3046 driver->owner = owner;
3047 driver->flags = flags;
3049 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3050 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3052 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3054 if (!driver->ttys || !driver->termios) {
3060 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3061 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3063 if (!driver->ports) {
3070 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3071 if (!driver->cdevs) {
3078 kfree(driver->ports);
3079 kfree(driver->ttys);
3080 kfree(driver->termios);
3081 kfree(driver->cdevs);
3083 return ERR_PTR(err);
3085 EXPORT_SYMBOL(__tty_alloc_driver);
3087 static void destruct_tty_driver(struct kref *kref)
3089 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3091 struct ktermios *tp;
3093 if (driver->flags & TTY_DRIVER_INSTALLED) {
3094 for (i = 0; i < driver->num; i++) {
3095 tp = driver->termios[i];
3097 driver->termios[i] = NULL;
3100 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3101 tty_unregister_device(driver, i);
3103 proc_tty_unregister_driver(driver);
3104 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3105 cdev_del(driver->cdevs[0]);
3107 kfree(driver->cdevs);
3108 kfree(driver->ports);
3109 kfree(driver->termios);
3110 kfree(driver->ttys);
3114 void tty_driver_kref_put(struct tty_driver *driver)
3116 kref_put(&driver->kref, destruct_tty_driver);
3118 EXPORT_SYMBOL(tty_driver_kref_put);
3120 void tty_set_operations(struct tty_driver *driver,
3121 const struct tty_operations *op)
3125 EXPORT_SYMBOL(tty_set_operations);
3127 void put_tty_driver(struct tty_driver *d)
3129 tty_driver_kref_put(d);
3131 EXPORT_SYMBOL(put_tty_driver);
3134 * Called by a tty driver to register itself.
3136 int tty_register_driver(struct tty_driver *driver)
3143 if (!driver->major) {
3144 error = alloc_chrdev_region(&dev, driver->minor_start,
3145 driver->num, driver->name);
3147 driver->major = MAJOR(dev);
3148 driver->minor_start = MINOR(dev);
3151 dev = MKDEV(driver->major, driver->minor_start);
3152 error = register_chrdev_region(dev, driver->num, driver->name);
3157 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3158 error = tty_cdev_add(driver, dev, 0, driver->num);
3160 goto err_unreg_char;
3163 mutex_lock(&tty_mutex);
3164 list_add(&driver->tty_drivers, &tty_drivers);
3165 mutex_unlock(&tty_mutex);
3167 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3168 for (i = 0; i < driver->num; i++) {
3169 d = tty_register_device(driver, i, NULL);
3172 goto err_unreg_devs;
3176 proc_tty_register_driver(driver);
3177 driver->flags |= TTY_DRIVER_INSTALLED;
3181 for (i--; i >= 0; i--)
3182 tty_unregister_device(driver, i);
3184 mutex_lock(&tty_mutex);
3185 list_del(&driver->tty_drivers);
3186 mutex_unlock(&tty_mutex);
3189 unregister_chrdev_region(dev, driver->num);
3193 EXPORT_SYMBOL(tty_register_driver);
3196 * Called by a tty driver to unregister itself.
3198 int tty_unregister_driver(struct tty_driver *driver)
3202 if (driver->refcount)
3205 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3207 mutex_lock(&tty_mutex);
3208 list_del(&driver->tty_drivers);
3209 mutex_unlock(&tty_mutex);
3213 EXPORT_SYMBOL(tty_unregister_driver);
3215 dev_t tty_devnum(struct tty_struct *tty)
3217 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3219 EXPORT_SYMBOL(tty_devnum);
3221 void tty_default_fops(struct file_operations *fops)
3226 static char *tty_devnode(struct device *dev, umode_t *mode)
3230 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3231 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3236 static int __init tty_class_init(void)
3238 tty_class = class_create(THIS_MODULE, "tty");
3239 if (IS_ERR(tty_class))
3240 return PTR_ERR(tty_class);
3241 tty_class->devnode = tty_devnode;
3245 postcore_initcall(tty_class_init);
3247 /* 3/2004 jmc: why do these devices exist? */
3248 static struct cdev tty_cdev, console_cdev;
3250 static ssize_t show_cons_active(struct device *dev,
3251 struct device_attribute *attr, char *buf)
3253 struct console *cs[16];
3259 for_each_console(c) {
3264 if ((c->flags & CON_ENABLED) == 0)
3267 if (i >= ARRAY_SIZE(cs))
3271 int index = cs[i]->index;
3272 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3274 /* don't resolve tty0 as some programs depend on it */
3275 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3276 count += tty_line_name(drv, index, buf + count);
3278 count += sprintf(buf + count, "%s%d",
3279 cs[i]->name, cs[i]->index);
3281 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3287 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3289 static struct attribute *cons_dev_attrs[] = {
3290 &dev_attr_active.attr,
3294 ATTRIBUTE_GROUPS(cons_dev);
3296 static struct device *consdev;
3298 void console_sysfs_notify(void)
3301 sysfs_notify(&consdev->kobj, NULL, "active");
3305 * Ok, now we can initialize the rest of the tty devices and can count
3306 * on memory allocations, interrupts etc..
3308 int __init tty_init(void)
3310 cdev_init(&tty_cdev, &tty_fops);
3311 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3312 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3313 panic("Couldn't register /dev/tty driver\n");
3314 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3316 cdev_init(&console_cdev, &console_fops);
3317 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3318 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3319 panic("Couldn't register /dev/console driver\n");
3320 consdev = device_create_with_groups(tty_class, NULL,
3321 MKDEV(TTYAUX_MAJOR, 1), NULL,
3322 cons_dev_groups, "console");
3323 if (IS_ERR(consdev))
3327 vty_init(&console_fops);