2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched/signal.h>
73 #include <linux/sched/task.h>
74 #include <linux/interrupt.h>
75 #include <linux/tty.h>
76 #include <linux/tty_driver.h>
77 #include <linux/tty_flip.h>
78 #include <linux/devpts_fs.h>
79 #include <linux/file.h>
80 #include <linux/fdtable.h>
81 #include <linux/console.h>
82 #include <linux/timer.h>
83 #include <linux/ctype.h>
86 #include <linux/string.h>
87 #include <linux/slab.h>
88 #include <linux/poll.h>
89 #include <linux/proc_fs.h>
90 #include <linux/init.h>
91 #include <linux/module.h>
92 #include <linux/device.h>
93 #include <linux/wait.h>
94 #include <linux/bitops.h>
95 #include <linux/delay.h>
96 #include <linux/seq_file.h>
97 #include <linux/serial.h>
98 #include <linux/ratelimit.h>
100 #include <linux/uaccess.h>
102 #include <linux/kbd_kern.h>
103 #include <linux/vt_kern.h>
104 #include <linux/selection.h>
106 #include <linux/kmod.h>
107 #include <linux/nsproxy.h>
109 #undef TTY_DEBUG_HANGUP
110 #ifdef TTY_DEBUG_HANGUP
111 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
113 # define tty_debug_hangup(tty, f, args...) do { } while (0)
116 #define TTY_PARANOIA_CHECK 1
117 #define CHECK_TTY_COUNT 1
119 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
120 .c_iflag = ICRNL | IXON,
121 .c_oflag = OPOST | ONLCR,
122 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
123 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
124 ECHOCTL | ECHOKE | IEXTEN,
128 /* .c_line = N_TTY, */
131 EXPORT_SYMBOL(tty_std_termios);
133 /* This list gets poked at by procfs and various bits of boot up code. This
134 could do with some rationalisation such as pulling the tty proc function
137 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
139 /* Mutex to protect creating and releasing a tty */
140 DEFINE_MUTEX(tty_mutex);
142 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
143 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
144 ssize_t redirected_tty_write(struct file *, const char __user *,
146 static unsigned int tty_poll(struct file *, poll_table *);
147 static int tty_open(struct inode *, struct file *);
148 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
150 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
153 #define tty_compat_ioctl NULL
155 static int __tty_fasync(int fd, struct file *filp, int on);
156 static int tty_fasync(int fd, struct file *filp, int on);
157 static void release_tty(struct tty_struct *tty, int idx);
160 * free_tty_struct - free a disused tty
161 * @tty: tty struct to free
163 * Free the write buffers, tty queue and tty memory itself.
165 * Locking: none. Must be called after tty is definitely unused
168 static void free_tty_struct(struct tty_struct *tty)
170 tty_ldisc_deinit(tty);
171 put_device(tty->dev);
172 kfree(tty->write_buf);
173 tty->magic = 0xDEADDEAD;
177 static inline struct tty_struct *file_tty(struct file *file)
179 return ((struct tty_file_private *)file->private_data)->tty;
182 int tty_alloc_file(struct file *file)
184 struct tty_file_private *priv;
186 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
190 file->private_data = priv;
195 /* Associate a new file with the tty structure */
196 void tty_add_file(struct tty_struct *tty, struct file *file)
198 struct tty_file_private *priv = file->private_data;
203 spin_lock(&tty->files_lock);
204 list_add(&priv->list, &tty->tty_files);
205 spin_unlock(&tty->files_lock);
209 * tty_free_file - free file->private_data
211 * This shall be used only for fail path handling when tty_add_file was not
214 void tty_free_file(struct file *file)
216 struct tty_file_private *priv = file->private_data;
218 file->private_data = NULL;
222 /* Delete file from its tty */
223 static void tty_del_file(struct file *file)
225 struct tty_file_private *priv = file->private_data;
226 struct tty_struct *tty = priv->tty;
228 spin_lock(&tty->files_lock);
229 list_del(&priv->list);
230 spin_unlock(&tty->files_lock);
235 * tty_name - return tty naming
236 * @tty: tty structure
238 * Convert a tty structure into a name. The name reflects the kernel
239 * naming policy and if udev is in use may not reflect user space
244 const char *tty_name(const struct tty_struct *tty)
246 if (!tty) /* Hmm. NULL pointer. That's fun. */
251 EXPORT_SYMBOL(tty_name);
253 const char *tty_driver_name(const struct tty_struct *tty)
255 if (!tty || !tty->driver)
257 return tty->driver->name;
260 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
263 #ifdef TTY_PARANOIA_CHECK
265 pr_warn("(%d:%d): %s: NULL tty\n",
266 imajor(inode), iminor(inode), routine);
269 if (tty->magic != TTY_MAGIC) {
270 pr_warn("(%d:%d): %s: bad magic number\n",
271 imajor(inode), iminor(inode), routine);
278 /* Caller must hold tty_lock */
279 static int check_tty_count(struct tty_struct *tty, const char *routine)
281 #ifdef CHECK_TTY_COUNT
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 * @dev_t: 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 file *file, const char __user *buf,
439 size_t count, loff_t *ppos)
444 /* No kernel lock held - none needed ;) */
445 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
447 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
450 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
453 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
456 static long hung_up_tty_compat_ioctl(struct file *file,
457 unsigned int cmd, unsigned long arg)
459 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
462 static int hung_up_tty_fasync(int fd, struct file *file, int on)
467 static void tty_show_fdinfo(struct seq_file *m, struct file *file)
469 struct tty_struct *tty = file_tty(file);
471 if (tty && tty->ops && tty->ops->show_fdinfo)
472 tty->ops->show_fdinfo(tty, m);
475 static const struct file_operations tty_fops = {
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 = redirected_tty_write,
493 .unlocked_ioctl = tty_ioctl,
494 .compat_ioctl = tty_compat_ioctl,
496 .release = tty_release,
497 .fasync = tty_fasync,
500 static const struct file_operations hung_up_tty_fops = {
502 .read = hung_up_tty_read,
503 .write = hung_up_tty_write,
504 .poll = hung_up_tty_poll,
505 .unlocked_ioctl = hung_up_tty_ioctl,
506 .compat_ioctl = hung_up_tty_compat_ioctl,
507 .release = tty_release,
508 .fasync = hung_up_tty_fasync,
511 static DEFINE_SPINLOCK(redirect_lock);
512 static struct file *redirect;
515 * tty_wakeup - request more data
518 * Internal and external helper for wakeups of tty. This function
519 * informs the line discipline if present that the driver is ready
520 * to receive more output data.
523 void tty_wakeup(struct tty_struct *tty)
525 struct tty_ldisc *ld;
527 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
528 ld = tty_ldisc_ref(tty);
530 if (ld->ops->write_wakeup)
531 ld->ops->write_wakeup(tty);
535 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
538 EXPORT_SYMBOL_GPL(tty_wakeup);
541 * __tty_hangup - actual handler for hangup events
544 * This can be called by a "kworker" kernel thread. That is process
545 * synchronous but doesn't hold any locks, so we need to make sure we
546 * have the appropriate locks for what we're doing.
548 * The hangup event clears any pending redirections onto the hung up
549 * device. It ensures future writes will error and it does the needed
550 * line discipline hangup and signal delivery. The tty object itself
555 * redirect lock for undoing redirection
556 * file list lock for manipulating list of ttys
557 * tty_ldiscs_lock from called functions
558 * termios_rwsem resetting termios data
559 * tasklist_lock to walk task list for hangup event
560 * ->siglock to protect ->signal/->sighand
562 static void __tty_hangup(struct tty_struct *tty, int exit_session)
564 struct file *cons_filp = NULL;
565 struct file *filp, *f = NULL;
566 struct tty_file_private *priv;
567 int closecount = 0, n;
574 spin_lock(&redirect_lock);
575 if (redirect && file_tty(redirect) == tty) {
579 spin_unlock(&redirect_lock);
583 if (test_bit(TTY_HUPPED, &tty->flags)) {
589 * Some console devices aren't actually hung up for technical and
590 * historical reasons, which can lead to indefinite interruptible
591 * sleep in n_tty_read(). The following explicitly tells
592 * n_tty_read() to abort readers.
594 set_bit(TTY_HUPPING, &tty->flags);
596 /* inuse_filps is protected by the single tty lock,
597 this really needs to change if we want to flush the
598 workqueue with the lock held */
599 check_tty_count(tty, "tty_hangup");
601 spin_lock(&tty->files_lock);
602 /* This breaks for file handles being sent over AF_UNIX sockets ? */
603 list_for_each_entry(priv, &tty->tty_files, list) {
605 if (filp->f_op->write == redirected_tty_write)
607 if (filp->f_op->write != tty_write)
610 __tty_fasync(-1, filp, 0); /* can't block */
611 filp->f_op = &hung_up_tty_fops;
613 spin_unlock(&tty->files_lock);
615 refs = tty_signal_session_leader(tty, exit_session);
616 /* Account for the p->signal references we killed */
620 tty_ldisc_hangup(tty, cons_filp != NULL);
622 spin_lock_irq(&tty->ctrl_lock);
623 clear_bit(TTY_THROTTLED, &tty->flags);
624 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
625 put_pid(tty->session);
629 tty->ctrl_status = 0;
630 spin_unlock_irq(&tty->ctrl_lock);
633 * If one of the devices matches a console pointer, we
634 * cannot just call hangup() because that will cause
635 * tty->count and state->count to go out of sync.
636 * So we just call close() the right number of times.
640 for (n = 0; n < closecount; n++)
641 tty->ops->close(tty, cons_filp);
642 } else if (tty->ops->hangup)
643 tty->ops->hangup(tty);
645 * We don't want to have driver/ldisc interactions beyond the ones
646 * we did here. The driver layer expects no calls after ->hangup()
647 * from the ldisc side, which is now guaranteed.
649 set_bit(TTY_HUPPED, &tty->flags);
650 clear_bit(TTY_HUPPING, &tty->flags);
657 static void do_tty_hangup(struct work_struct *work)
659 struct tty_struct *tty =
660 container_of(work, struct tty_struct, hangup_work);
662 __tty_hangup(tty, 0);
666 * tty_hangup - trigger a hangup event
667 * @tty: tty to hangup
669 * A carrier loss (virtual or otherwise) has occurred on this like
670 * schedule a hangup sequence to run after this event.
673 void tty_hangup(struct tty_struct *tty)
675 tty_debug_hangup(tty, "hangup\n");
676 schedule_work(&tty->hangup_work);
679 EXPORT_SYMBOL(tty_hangup);
682 * tty_vhangup - process vhangup
683 * @tty: tty to hangup
685 * The user has asked via system call for the terminal to be hung up.
686 * We do this synchronously so that when the syscall returns the process
687 * is complete. That guarantee is necessary for security reasons.
690 void tty_vhangup(struct tty_struct *tty)
692 tty_debug_hangup(tty, "vhangup\n");
693 __tty_hangup(tty, 0);
696 EXPORT_SYMBOL(tty_vhangup);
700 * tty_vhangup_self - process vhangup for own ctty
702 * Perform a vhangup on the current controlling tty
705 void tty_vhangup_self(void)
707 struct tty_struct *tty;
709 tty = get_current_tty();
717 * tty_vhangup_session - hangup session leader exit
718 * @tty: tty to hangup
720 * The session leader is exiting and hanging up its controlling terminal.
721 * Every process in the foreground process group is signalled SIGHUP.
723 * We do this synchronously so that when the syscall returns the process
724 * is complete. That guarantee is necessary for security reasons.
727 void tty_vhangup_session(struct tty_struct *tty)
729 tty_debug_hangup(tty, "session hangup\n");
730 __tty_hangup(tty, 1);
734 * tty_hung_up_p - was tty hung up
735 * @filp: file pointer of tty
737 * Return true if the tty has been subject to a vhangup or a carrier
741 int tty_hung_up_p(struct file *filp)
743 return (filp && filp->f_op == &hung_up_tty_fops);
746 EXPORT_SYMBOL(tty_hung_up_p);
749 * stop_tty - propagate flow control
752 * Perform flow control to the driver. May be called
753 * on an already stopped device and will not re-call the driver
756 * This functionality is used by both the line disciplines for
757 * halting incoming flow and by the driver. It may therefore be
758 * called from any context, may be under the tty atomic_write_lock
765 void __stop_tty(struct tty_struct *tty)
774 void stop_tty(struct tty_struct *tty)
778 spin_lock_irqsave(&tty->flow_lock, flags);
780 spin_unlock_irqrestore(&tty->flow_lock, flags);
782 EXPORT_SYMBOL(stop_tty);
785 * start_tty - propagate flow control
788 * Start a tty that has been stopped if at all possible. If this
789 * tty was previous stopped and is now being started, the driver
790 * start method is invoked and the line discipline woken.
796 void __start_tty(struct tty_struct *tty)
798 if (!tty->stopped || tty->flow_stopped)
802 tty->ops->start(tty);
806 void start_tty(struct tty_struct *tty)
810 spin_lock_irqsave(&tty->flow_lock, flags);
812 spin_unlock_irqrestore(&tty->flow_lock, flags);
814 EXPORT_SYMBOL(start_tty);
816 static void tty_update_time(struct timespec *time)
818 unsigned long sec = get_seconds();
821 * We only care if the two values differ in anything other than the
822 * lower three bits (i.e every 8 seconds). If so, then we can update
823 * the time of the tty device, otherwise it could be construded as a
824 * security leak to let userspace know the exact timing of the tty.
826 if ((sec ^ time->tv_sec) & ~7)
831 * tty_read - read method for tty device files
832 * @file: pointer to tty file
834 * @count: size of user buffer
837 * Perform the read system call function on this terminal device. Checks
838 * for hung up devices before calling the line discipline method.
841 * Locks the line discipline internally while needed. Multiple
842 * read calls may be outstanding in parallel.
845 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
849 struct inode *inode = file_inode(file);
850 struct tty_struct *tty = file_tty(file);
851 struct tty_ldisc *ld;
853 if (tty_paranoia_check(tty, inode, "tty_read"))
855 if (!tty || tty_io_error(tty))
858 /* We want to wait for the line discipline to sort out in this
860 ld = tty_ldisc_ref_wait(tty);
862 return hung_up_tty_read(file, buf, count, ppos);
864 i = ld->ops->read(tty, file, buf, count);
870 tty_update_time(&inode->i_atime);
875 static void tty_write_unlock(struct tty_struct *tty)
877 mutex_unlock(&tty->atomic_write_lock);
878 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
881 static int tty_write_lock(struct tty_struct *tty, int ndelay)
883 if (!mutex_trylock(&tty->atomic_write_lock)) {
886 if (mutex_lock_interruptible(&tty->atomic_write_lock))
893 * Split writes up in sane blocksizes to avoid
894 * denial-of-service type attacks
896 static inline ssize_t do_tty_write(
897 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
898 struct tty_struct *tty,
900 const char __user *buf,
903 ssize_t ret, written = 0;
906 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
911 * We chunk up writes into a temporary buffer. This
912 * simplifies low-level drivers immensely, since they
913 * don't have locking issues and user mode accesses.
915 * But if TTY_NO_WRITE_SPLIT is set, we should use a
918 * The default chunk-size is 2kB, because the NTTY
919 * layer has problems with bigger chunks. It will
920 * claim to be able to handle more characters than
923 * FIXME: This can probably go away now except that 64K chunks
924 * are too likely to fail unless switched to vmalloc...
927 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
932 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
933 if (tty->write_cnt < chunk) {
934 unsigned char *buf_chunk;
939 buf_chunk = kmalloc(chunk, GFP_KERNEL);
944 kfree(tty->write_buf);
945 tty->write_cnt = chunk;
946 tty->write_buf = buf_chunk;
949 /* Do the write .. */
955 if (copy_from_user(tty->write_buf, buf, size))
957 ret = write(tty, file, tty->write_buf, size);
966 if (signal_pending(current))
971 tty_update_time(&file_inode(file)->i_mtime);
975 tty_write_unlock(tty);
980 * tty_write_message - write a message to a certain tty, not just the console.
981 * @tty: the destination tty_struct
982 * @msg: the message to write
984 * This is used for messages that need to be redirected to a specific tty.
985 * We don't put it into the syslog queue right now maybe in the future if
988 * We must still hold the BTM and test the CLOSING flag for the moment.
991 void tty_write_message(struct tty_struct *tty, char *msg)
994 mutex_lock(&tty->atomic_write_lock);
996 if (tty->ops->write && tty->count > 0)
997 tty->ops->write(tty, msg, strlen(msg));
999 tty_write_unlock(tty);
1006 * tty_write - write method for tty device file
1007 * @file: tty file pointer
1008 * @buf: user data to write
1009 * @count: bytes to write
1012 * Write data to a tty device via the line discipline.
1015 * Locks the line discipline as required
1016 * Writes to the tty driver are serialized by the atomic_write_lock
1017 * and are then processed in chunks to the device. The line discipline
1018 * write method will not be invoked in parallel for each device.
1021 static ssize_t tty_write(struct file *file, const char __user *buf,
1022 size_t count, loff_t *ppos)
1024 struct tty_struct *tty = file_tty(file);
1025 struct tty_ldisc *ld;
1028 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1030 if (!tty || !tty->ops->write || tty_io_error(tty))
1032 /* Short term debug to catch buggy drivers */
1033 if (tty->ops->write_room == NULL)
1034 tty_err(tty, "missing write_room method\n");
1035 ld = tty_ldisc_ref_wait(tty);
1037 return hung_up_tty_write(file, buf, count, ppos);
1038 if (!ld->ops->write)
1041 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1042 tty_ldisc_deref(ld);
1046 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1047 size_t count, loff_t *ppos)
1049 struct file *p = NULL;
1051 spin_lock(&redirect_lock);
1053 p = get_file(redirect);
1054 spin_unlock(&redirect_lock);
1058 res = vfs_write(p, buf, count, &p->f_pos);
1062 return tty_write(file, buf, count, ppos);
1066 * tty_send_xchar - send priority character
1068 * Send a high priority character to the tty even if stopped
1070 * Locking: none for xchar method, write ordering for write method.
1073 int tty_send_xchar(struct tty_struct *tty, char ch)
1075 int was_stopped = tty->stopped;
1077 if (tty->ops->send_xchar) {
1078 down_read(&tty->termios_rwsem);
1079 tty->ops->send_xchar(tty, ch);
1080 up_read(&tty->termios_rwsem);
1084 if (tty_write_lock(tty, 0) < 0)
1085 return -ERESTARTSYS;
1087 down_read(&tty->termios_rwsem);
1090 tty->ops->write(tty, &ch, 1);
1093 up_read(&tty->termios_rwsem);
1094 tty_write_unlock(tty);
1098 static char ptychar[] = "pqrstuvwxyzabcde";
1101 * pty_line_name - generate name for a pty
1102 * @driver: the tty driver in use
1103 * @index: the minor number
1104 * @p: output buffer of at least 6 bytes
1106 * Generate a name from a driver reference and write it to the output
1111 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1113 int i = index + driver->name_base;
1114 /* ->name is initialized to "ttyp", but "tty" is expected */
1115 sprintf(p, "%s%c%x",
1116 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1117 ptychar[i >> 4 & 0xf], i & 0xf);
1121 * tty_line_name - generate name for a tty
1122 * @driver: the tty driver in use
1123 * @index: the minor number
1124 * @p: output buffer of at least 7 bytes
1126 * Generate a name from a driver reference and write it to the output
1131 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1133 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1134 return sprintf(p, "%s", driver->name);
1136 return sprintf(p, "%s%d", driver->name,
1137 index + driver->name_base);
1141 * tty_driver_lookup_tty() - find an existing tty, if any
1142 * @driver: the driver for the tty
1143 * @idx: the minor number
1145 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1146 * driver lookup() method returns an error.
1148 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1150 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1151 struct file *file, int idx)
1153 struct tty_struct *tty;
1155 if (driver->ops->lookup)
1157 tty = ERR_PTR(-EIO);
1159 tty = driver->ops->lookup(driver, file, idx);
1161 tty = driver->ttys[idx];
1169 * tty_init_termios - helper for termios setup
1170 * @tty: the tty to set up
1172 * Initialise the termios structures for this tty. Thus runs under
1173 * the tty_mutex currently so we can be relaxed about ordering.
1176 void tty_init_termios(struct tty_struct *tty)
1178 struct ktermios *tp;
1179 int idx = tty->index;
1181 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1182 tty->termios = tty->driver->init_termios;
1184 /* Check for lazy saved data */
1185 tp = tty->driver->termios[idx];
1188 tty->termios.c_line = tty->driver->init_termios.c_line;
1190 tty->termios = tty->driver->init_termios;
1192 /* Compatibility until drivers always set this */
1193 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1194 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1196 EXPORT_SYMBOL_GPL(tty_init_termios);
1198 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1200 tty_init_termios(tty);
1201 tty_driver_kref_get(driver);
1203 driver->ttys[tty->index] = tty;
1206 EXPORT_SYMBOL_GPL(tty_standard_install);
1209 * tty_driver_install_tty() - install a tty entry in the driver
1210 * @driver: the driver for the tty
1213 * Install a tty object into the driver tables. The tty->index field
1214 * will be set by the time this is called. This method is responsible
1215 * for ensuring any need additional structures are allocated and
1218 * Locking: tty_mutex for now
1220 static int tty_driver_install_tty(struct tty_driver *driver,
1221 struct tty_struct *tty)
1223 return driver->ops->install ? driver->ops->install(driver, tty) :
1224 tty_standard_install(driver, tty);
1228 * tty_driver_remove_tty() - remove a tty from the driver tables
1229 * @driver: the driver for the tty
1230 * @idx: the minor number
1232 * Remvoe a tty object from the driver tables. The tty->index field
1233 * will be set by the time this is called.
1235 * Locking: tty_mutex for now
1237 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1239 if (driver->ops->remove)
1240 driver->ops->remove(driver, tty);
1242 driver->ttys[tty->index] = NULL;
1246 * tty_reopen() - fast re-open of an open tty
1247 * @tty - the tty to open
1249 * Return 0 on success, -errno on error.
1250 * Re-opens on master ptys are not allowed and return -EIO.
1252 * Locking: Caller must hold tty_lock
1254 static int tty_reopen(struct tty_struct *tty)
1256 struct tty_driver *driver = tty->driver;
1257 struct tty_ldisc *ld;
1260 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1261 driver->subtype == PTY_TYPE_MASTER)
1267 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1270 ld = tty_ldisc_ref_wait(tty);
1272 tty_ldisc_deref(ld);
1274 retval = tty_ldisc_lock(tty, 5 * HZ);
1279 retval = tty_ldisc_reinit(tty, tty->termios.c_line);
1280 tty_ldisc_unlock(tty);
1290 * tty_init_dev - initialise a tty device
1291 * @driver: tty driver we are opening a device on
1292 * @idx: device index
1293 * @ret_tty: returned tty structure
1295 * Prepare a tty device. This may not be a "new" clean device but
1296 * could also be an active device. The pty drivers require special
1297 * handling because of this.
1300 * The function is called under the tty_mutex, which
1301 * protects us from the tty struct or driver itself going away.
1303 * On exit the tty device has the line discipline attached and
1304 * a reference count of 1. If a pair was created for pty/tty use
1305 * and the other was a pty master then it too has a reference count of 1.
1307 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1308 * failed open. The new code protects the open with a mutex, so it's
1309 * really quite straightforward. The mutex locking can probably be
1310 * relaxed for the (most common) case of reopening a tty.
1313 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1315 struct tty_struct *tty;
1319 * First time open is complex, especially for PTY devices.
1320 * This code guarantees that either everything succeeds and the
1321 * TTY is ready for operation, or else the table slots are vacated
1322 * and the allocated memory released. (Except that the termios
1326 if (!try_module_get(driver->owner))
1327 return ERR_PTR(-ENODEV);
1329 tty = alloc_tty_struct(driver, idx);
1332 goto err_module_put;
1336 retval = tty_driver_install_tty(driver, tty);
1341 tty->port = driver->ports[idx];
1343 WARN_RATELIMIT(!tty->port,
1344 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1345 __func__, tty->driver->name);
1347 retval = tty_ldisc_lock(tty, 5 * HZ);
1349 goto err_release_lock;
1350 tty->port->itty = tty;
1353 * Structures all installed ... call the ldisc open routines.
1354 * If we fail here just call release_tty to clean up. No need
1355 * to decrement the use counts, as release_tty doesn't care.
1357 retval = tty_ldisc_setup(tty, tty->link);
1359 goto err_release_tty;
1360 tty_ldisc_unlock(tty);
1361 /* Return the tty locked so that it cannot vanish under the caller */
1366 free_tty_struct(tty);
1368 module_put(driver->owner);
1369 return ERR_PTR(retval);
1371 /* call the tty release_tty routine to clean out this slot */
1373 tty_ldisc_unlock(tty);
1374 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1378 release_tty(tty, idx);
1379 return ERR_PTR(retval);
1382 static void tty_free_termios(struct tty_struct *tty)
1384 struct ktermios *tp;
1385 int idx = tty->index;
1387 /* If the port is going to reset then it has no termios to save */
1388 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1391 /* Stash the termios data */
1392 tp = tty->driver->termios[idx];
1394 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1397 tty->driver->termios[idx] = tp;
1403 * tty_flush_works - flush all works of a tty/pty pair
1404 * @tty: tty device to flush works for (or either end of a pty pair)
1406 * Sync flush all works belonging to @tty (and the 'other' tty).
1408 static void tty_flush_works(struct tty_struct *tty)
1410 flush_work(&tty->SAK_work);
1411 flush_work(&tty->hangup_work);
1413 flush_work(&tty->link->SAK_work);
1414 flush_work(&tty->link->hangup_work);
1419 * release_one_tty - release tty structure memory
1420 * @kref: kref of tty we are obliterating
1422 * Releases memory associated with a tty structure, and clears out the
1423 * driver table slots. This function is called when a device is no longer
1424 * in use. It also gets called when setup of a device fails.
1427 * takes the file list lock internally when working on the list
1428 * of ttys that the driver keeps.
1430 * This method gets called from a work queue so that the driver private
1431 * cleanup ops can sleep (needed for USB at least)
1433 static void release_one_tty(struct work_struct *work)
1435 struct tty_struct *tty =
1436 container_of(work, struct tty_struct, hangup_work);
1437 struct tty_driver *driver = tty->driver;
1438 struct module *owner = driver->owner;
1440 if (tty->ops->cleanup)
1441 tty->ops->cleanup(tty);
1444 tty_driver_kref_put(driver);
1447 spin_lock(&tty->files_lock);
1448 list_del_init(&tty->tty_files);
1449 spin_unlock(&tty->files_lock);
1452 put_pid(tty->session);
1453 free_tty_struct(tty);
1456 static void queue_release_one_tty(struct kref *kref)
1458 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1460 /* The hangup queue is now free so we can reuse it rather than
1461 waste a chunk of memory for each port */
1462 INIT_WORK(&tty->hangup_work, release_one_tty);
1463 schedule_work(&tty->hangup_work);
1467 * tty_kref_put - release a tty kref
1470 * Release a reference to a tty device and if need be let the kref
1471 * layer destruct the object for us
1474 void tty_kref_put(struct tty_struct *tty)
1477 kref_put(&tty->kref, queue_release_one_tty);
1479 EXPORT_SYMBOL(tty_kref_put);
1482 * release_tty - release tty structure memory
1484 * Release both @tty and a possible linked partner (think pty pair),
1485 * and decrement the refcount of the backing module.
1489 * takes the file list lock internally when working on the list
1490 * of ttys that the driver keeps.
1493 static void release_tty(struct tty_struct *tty, int idx)
1495 /* This should always be true but check for the moment */
1496 WARN_ON(tty->index != idx);
1497 WARN_ON(!mutex_is_locked(&tty_mutex));
1498 if (tty->ops->shutdown)
1499 tty->ops->shutdown(tty);
1500 tty_free_termios(tty);
1501 tty_driver_remove_tty(tty->driver, tty);
1502 tty->port->itty = NULL;
1504 tty->link->port->itty = NULL;
1505 tty_buffer_cancel_work(tty->port);
1507 tty_buffer_cancel_work(tty->link->port);
1509 tty_kref_put(tty->link);
1514 * tty_release_checks - check a tty before real release
1515 * @tty: tty to check
1516 * @o_tty: link of @tty (if any)
1517 * @idx: index of the tty
1519 * Performs some paranoid checking before true release of the @tty.
1520 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1522 static int tty_release_checks(struct tty_struct *tty, int idx)
1524 #ifdef TTY_PARANOIA_CHECK
1525 if (idx < 0 || idx >= tty->driver->num) {
1526 tty_debug(tty, "bad idx %d\n", idx);
1530 /* not much to check for devpts */
1531 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1534 if (tty != tty->driver->ttys[idx]) {
1535 tty_debug(tty, "bad driver table[%d] = %p\n",
1536 idx, tty->driver->ttys[idx]);
1539 if (tty->driver->other) {
1540 struct tty_struct *o_tty = tty->link;
1542 if (o_tty != tty->driver->other->ttys[idx]) {
1543 tty_debug(tty, "bad other table[%d] = %p\n",
1544 idx, tty->driver->other->ttys[idx]);
1547 if (o_tty->link != tty) {
1548 tty_debug(tty, "bad link = %p\n", o_tty->link);
1557 * tty_kclose - closes tty opened by tty_kopen
1560 * Performs the final steps to release and free a tty device. It is the
1561 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1562 * flag on tty->port.
1564 void tty_kclose(struct tty_struct *tty)
1567 * Ask the line discipline code to release its structures
1569 tty_ldisc_release(tty);
1571 /* Wait for pending work before tty destruction commmences */
1572 tty_flush_works(tty);
1574 tty_debug_hangup(tty, "freeing structure\n");
1576 * The release_tty function takes care of the details of clearing
1577 * the slots and preserving the termios structure. The tty_unlock_pair
1578 * should be safe as we keep a kref while the tty is locked (so the
1579 * unlock never unlocks a freed tty).
1581 mutex_lock(&tty_mutex);
1582 tty_port_set_kopened(tty->port, 0);
1583 release_tty(tty, tty->index);
1584 mutex_unlock(&tty_mutex);
1586 EXPORT_SYMBOL_GPL(tty_kclose);
1589 * tty_release_struct - release a tty struct
1591 * @idx: index of the tty
1593 * Performs the final steps to release and free a tty device. It is
1594 * roughly the reverse of tty_init_dev.
1596 void tty_release_struct(struct tty_struct *tty, int idx)
1599 * Ask the line discipline code to release its structures
1601 tty_ldisc_release(tty);
1603 /* Wait for pending work before tty destruction commmences */
1604 tty_flush_works(tty);
1606 tty_debug_hangup(tty, "freeing structure\n");
1608 * The release_tty function takes care of the details of clearing
1609 * the slots and preserving the termios structure. The tty_unlock_pair
1610 * should be safe as we keep a kref while the tty is locked (so the
1611 * unlock never unlocks a freed tty).
1613 mutex_lock(&tty_mutex);
1614 release_tty(tty, idx);
1615 mutex_unlock(&tty_mutex);
1617 EXPORT_SYMBOL_GPL(tty_release_struct);
1620 * tty_release - vfs callback for close
1621 * @inode: inode of tty
1622 * @filp: file pointer for handle to tty
1624 * Called the last time each file handle is closed that references
1625 * this tty. There may however be several such references.
1628 * Takes bkl. See tty_release_dev
1630 * Even releasing the tty structures is a tricky business.. We have
1631 * to be very careful that the structures are all released at the
1632 * same time, as interrupts might otherwise get the wrong pointers.
1634 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1635 * lead to double frees or releasing memory still in use.
1638 int tty_release(struct inode *inode, struct file *filp)
1640 struct tty_struct *tty = file_tty(filp);
1641 struct tty_struct *o_tty = NULL;
1642 int do_sleep, final;
1647 if (tty_paranoia_check(tty, inode, __func__))
1651 check_tty_count(tty, __func__);
1653 __tty_fasync(-1, filp, 0);
1656 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1657 tty->driver->subtype == PTY_TYPE_MASTER)
1660 if (tty_release_checks(tty, idx)) {
1665 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1667 if (tty->ops->close)
1668 tty->ops->close(tty, filp);
1670 /* If tty is pty master, lock the slave pty (stable lock order) */
1671 tty_lock_slave(o_tty);
1674 * Sanity check: if tty->count is going to zero, there shouldn't be
1675 * any waiters on tty->read_wait or tty->write_wait. We test the
1676 * wait queues and kick everyone out _before_ actually starting to
1677 * close. This ensures that we won't block while releasing the tty
1680 * The test for the o_tty closing is necessary, since the master and
1681 * slave sides may close in any order. If the slave side closes out
1682 * first, its count will be one, since the master side holds an open.
1683 * Thus this test wouldn't be triggered at the time the slave closed,
1689 if (tty->count <= 1) {
1690 if (waitqueue_active(&tty->read_wait)) {
1691 wake_up_poll(&tty->read_wait, POLLIN);
1694 if (waitqueue_active(&tty->write_wait)) {
1695 wake_up_poll(&tty->write_wait, POLLOUT);
1699 if (o_tty && o_tty->count <= 1) {
1700 if (waitqueue_active(&o_tty->read_wait)) {
1701 wake_up_poll(&o_tty->read_wait, POLLIN);
1704 if (waitqueue_active(&o_tty->write_wait)) {
1705 wake_up_poll(&o_tty->write_wait, POLLOUT);
1714 tty_warn(tty, "read/write wait queue active!\n");
1716 schedule_timeout_killable(timeout);
1717 if (timeout < 120 * HZ)
1718 timeout = 2 * timeout + 1;
1720 timeout = MAX_SCHEDULE_TIMEOUT;
1724 if (--o_tty->count < 0) {
1725 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1729 if (--tty->count < 0) {
1730 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1735 * We've decremented tty->count, so we need to remove this file
1736 * descriptor off the tty->tty_files list; this serves two
1738 * - check_tty_count sees the correct number of file descriptors
1739 * associated with this tty.
1740 * - do_tty_hangup no longer sees this file descriptor as
1741 * something that needs to be handled for hangups.
1746 * Perform some housekeeping before deciding whether to return.
1748 * If _either_ side is closing, make sure there aren't any
1749 * processes that still think tty or o_tty is their controlling
1753 read_lock(&tasklist_lock);
1754 session_clear_tty(tty->session);
1756 session_clear_tty(o_tty->session);
1757 read_unlock(&tasklist_lock);
1760 /* check whether both sides are closing ... */
1761 final = !tty->count && !(o_tty && o_tty->count);
1763 tty_unlock_slave(o_tty);
1766 /* At this point, the tty->count == 0 should ensure a dead tty
1767 cannot be re-opened by a racing opener */
1772 tty_debug_hangup(tty, "final close\n");
1774 tty_release_struct(tty, idx);
1779 * tty_open_current_tty - get locked tty of current task
1780 * @device: device number
1781 * @filp: file pointer to tty
1782 * @return: locked tty of the current task iff @device is /dev/tty
1784 * Performs a re-open of the current task's controlling tty.
1786 * We cannot return driver and index like for the other nodes because
1787 * devpts will not work then. It expects inodes to be from devpts FS.
1789 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1791 struct tty_struct *tty;
1794 if (device != MKDEV(TTYAUX_MAJOR, 0))
1797 tty = get_current_tty();
1799 return ERR_PTR(-ENXIO);
1801 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1804 tty_kref_put(tty); /* safe to drop the kref now */
1806 retval = tty_reopen(tty);
1809 tty = ERR_PTR(retval);
1815 * tty_lookup_driver - lookup a tty driver for a given device file
1816 * @device: device number
1817 * @filp: file pointer to tty
1818 * @index: index for the device in the @return driver
1819 * @return: driver for this inode (with increased refcount)
1821 * If @return is not erroneous, the caller is responsible to decrement the
1822 * refcount by tty_driver_kref_put.
1824 * Locking: tty_mutex protects get_tty_driver
1826 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1829 struct tty_driver *driver;
1833 case MKDEV(TTY_MAJOR, 0): {
1834 extern struct tty_driver *console_driver;
1835 driver = tty_driver_kref_get(console_driver);
1836 *index = fg_console;
1840 case MKDEV(TTYAUX_MAJOR, 1): {
1841 struct tty_driver *console_driver = console_device(index);
1842 if (console_driver) {
1843 driver = tty_driver_kref_get(console_driver);
1844 if (driver && filp) {
1845 /* Don't let /dev/console block */
1846 filp->f_flags |= O_NONBLOCK;
1850 return ERR_PTR(-ENODEV);
1853 driver = get_tty_driver(device, index);
1855 return ERR_PTR(-ENODEV);
1862 * tty_kopen - open a tty device for kernel
1863 * @device: dev_t of device to open
1865 * Opens tty exclusively for kernel. Performs the driver lookup,
1866 * makes sure it's not already opened and performs the first-time
1867 * tty initialization.
1869 * Returns the locked initialized &tty_struct
1871 * Claims the global tty_mutex to serialize:
1872 * - concurrent first-time tty initialization
1873 * - concurrent tty driver removal w/ lookup
1874 * - concurrent tty removal from driver table
1876 struct tty_struct *tty_kopen(dev_t device)
1878 struct tty_struct *tty;
1879 struct tty_driver *driver = NULL;
1882 mutex_lock(&tty_mutex);
1883 driver = tty_lookup_driver(device, NULL, &index);
1884 if (IS_ERR(driver)) {
1885 mutex_unlock(&tty_mutex);
1886 return ERR_CAST(driver);
1889 /* check whether we're reopening an existing tty */
1890 tty = tty_driver_lookup_tty(driver, NULL, index);
1895 /* drop kref from tty_driver_lookup_tty() */
1897 tty = ERR_PTR(-EBUSY);
1898 } else { /* tty_init_dev returns tty with the tty_lock held */
1899 tty = tty_init_dev(driver, index);
1902 tty_port_set_kopened(tty->port, 1);
1905 mutex_unlock(&tty_mutex);
1906 tty_driver_kref_put(driver);
1909 EXPORT_SYMBOL_GPL(tty_kopen);
1912 * tty_open_by_driver - open a tty device
1913 * @device: dev_t of device to open
1914 * @inode: inode of device file
1915 * @filp: file pointer to tty
1917 * Performs the driver lookup, checks for a reopen, or otherwise
1918 * performs the first-time tty initialization.
1920 * Returns the locked initialized or re-opened &tty_struct
1922 * Claims the global tty_mutex to serialize:
1923 * - concurrent first-time tty initialization
1924 * - concurrent tty driver removal w/ lookup
1925 * - concurrent tty removal from driver table
1927 static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
1930 struct tty_struct *tty;
1931 struct tty_driver *driver = NULL;
1935 mutex_lock(&tty_mutex);
1936 driver = tty_lookup_driver(device, filp, &index);
1937 if (IS_ERR(driver)) {
1938 mutex_unlock(&tty_mutex);
1939 return ERR_CAST(driver);
1942 /* check whether we're reopening an existing tty */
1943 tty = tty_driver_lookup_tty(driver, filp, index);
1945 mutex_unlock(&tty_mutex);
1950 if (tty_port_kopened(tty->port)) {
1952 mutex_unlock(&tty_mutex);
1953 tty = ERR_PTR(-EBUSY);
1956 mutex_unlock(&tty_mutex);
1957 retval = tty_lock_interruptible(tty);
1958 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
1960 if (retval == -EINTR)
1961 retval = -ERESTARTSYS;
1962 tty = ERR_PTR(retval);
1965 retval = tty_reopen(tty);
1968 tty = ERR_PTR(retval);
1970 } else { /* Returns with the tty_lock held for now */
1971 tty = tty_init_dev(driver, index);
1972 mutex_unlock(&tty_mutex);
1975 tty_driver_kref_put(driver);
1980 * tty_open - open a tty device
1981 * @inode: inode of device file
1982 * @filp: file pointer to tty
1984 * tty_open and tty_release keep up the tty count that contains the
1985 * number of opens done on a tty. We cannot use the inode-count, as
1986 * different inodes might point to the same tty.
1988 * Open-counting is needed for pty masters, as well as for keeping
1989 * track of serial lines: DTR is dropped when the last close happens.
1990 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1992 * The termios state of a pty is reset on first open so that
1993 * settings don't persist across reuse.
1995 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1996 * tty->count should protect the rest.
1997 * ->siglock protects ->signal/->sighand
1999 * Note: the tty_unlock/lock cases without a ref are only safe due to
2003 static int tty_open(struct inode *inode, struct file *filp)
2005 struct tty_struct *tty;
2007 dev_t device = inode->i_rdev;
2008 unsigned saved_flags = filp->f_flags;
2010 nonseekable_open(inode, filp);
2013 retval = tty_alloc_file(filp);
2017 tty = tty_open_current_tty(device, filp);
2019 tty = tty_open_by_driver(device, inode, filp);
2022 tty_free_file(filp);
2023 retval = PTR_ERR(tty);
2024 if (retval != -EAGAIN || signal_pending(current))
2030 tty_add_file(tty, filp);
2032 check_tty_count(tty, __func__);
2033 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2036 retval = tty->ops->open(tty, filp);
2039 filp->f_flags = saved_flags;
2042 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2044 tty_unlock(tty); /* need to call tty_release without BTM */
2045 tty_release(inode, filp);
2046 if (retval != -ERESTARTSYS)
2049 if (signal_pending(current))
2054 * Need to reset f_op in case a hangup happened.
2056 if (tty_hung_up_p(filp))
2057 filp->f_op = &tty_fops;
2060 clear_bit(TTY_HUPPED, &tty->flags);
2062 noctty = (filp->f_flags & O_NOCTTY) ||
2063 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2064 device == MKDEV(TTYAUX_MAJOR, 1) ||
2065 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2066 tty->driver->subtype == PTY_TYPE_MASTER);
2068 tty_open_proc_set_tty(filp, tty);
2076 * tty_poll - check tty status
2077 * @filp: file being polled
2078 * @wait: poll wait structures to update
2080 * Call the line discipline polling method to obtain the poll
2081 * status of the device.
2083 * Locking: locks called line discipline but ldisc poll method
2084 * may be re-entered freely by other callers.
2087 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2089 struct tty_struct *tty = file_tty(filp);
2090 struct tty_ldisc *ld;
2093 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2096 ld = tty_ldisc_ref_wait(tty);
2098 return hung_up_tty_poll(filp, wait);
2100 ret = ld->ops->poll(tty, filp, wait);
2101 tty_ldisc_deref(ld);
2105 static int __tty_fasync(int fd, struct file *filp, int on)
2107 struct tty_struct *tty = file_tty(filp);
2108 unsigned long flags;
2111 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2114 retval = fasync_helper(fd, filp, on, &tty->fasync);
2122 spin_lock_irqsave(&tty->ctrl_lock, flags);
2125 type = PIDTYPE_PGID;
2127 pid = task_pid(current);
2131 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2132 __f_setown(filp, pid, type, 0);
2140 static int tty_fasync(int fd, struct file *filp, int on)
2142 struct tty_struct *tty = file_tty(filp);
2143 int retval = -ENOTTY;
2146 if (!tty_hung_up_p(filp))
2147 retval = __tty_fasync(fd, filp, on);
2154 * tiocsti - fake input character
2155 * @tty: tty to fake input into
2156 * @p: pointer to character
2158 * Fake input to a tty device. Does the necessary locking and
2161 * FIXME: does not honour flow control ??
2164 * Called functions take tty_ldiscs_lock
2165 * current->signal->tty check is safe without locks
2167 * FIXME: may race normal receive processing
2170 static int tiocsti(struct tty_struct *tty, char __user *p)
2173 struct tty_ldisc *ld;
2175 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2177 if (get_user(ch, p))
2179 tty_audit_tiocsti(tty, ch);
2180 ld = tty_ldisc_ref_wait(tty);
2183 if (ld->ops->receive_buf)
2184 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2185 tty_ldisc_deref(ld);
2190 * tiocgwinsz - implement window query ioctl
2192 * @arg: user buffer for result
2194 * Copies the kernel idea of the window size into the user buffer.
2196 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2200 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2204 mutex_lock(&tty->winsize_mutex);
2205 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2206 mutex_unlock(&tty->winsize_mutex);
2208 return err ? -EFAULT: 0;
2212 * tty_do_resize - resize event
2213 * @tty: tty being resized
2214 * @rows: rows (character)
2215 * @cols: cols (character)
2217 * Update the termios variables and send the necessary signals to
2218 * peform a terminal resize correctly
2221 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2226 mutex_lock(&tty->winsize_mutex);
2227 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2230 /* Signal the foreground process group */
2231 pgrp = tty_get_pgrp(tty);
2233 kill_pgrp(pgrp, SIGWINCH, 1);
2238 mutex_unlock(&tty->winsize_mutex);
2241 EXPORT_SYMBOL(tty_do_resize);
2244 * tiocswinsz - implement window size set ioctl
2245 * @tty; tty side of tty
2246 * @arg: user buffer for result
2248 * Copies the user idea of the window size to the kernel. Traditionally
2249 * this is just advisory information but for the Linux console it
2250 * actually has driver level meaning and triggers a VC resize.
2253 * Driver dependent. The default do_resize method takes the
2254 * tty termios mutex and ctrl_lock. The console takes its own lock
2255 * then calls into the default method.
2258 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2260 struct winsize tmp_ws;
2261 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2264 if (tty->ops->resize)
2265 return tty->ops->resize(tty, &tmp_ws);
2267 return tty_do_resize(tty, &tmp_ws);
2271 * tioccons - allow admin to move logical console
2272 * @file: the file to become console
2274 * Allow the administrator to move the redirected console device
2276 * Locking: uses redirect_lock to guard the redirect information
2279 static int tioccons(struct file *file)
2281 if (!capable(CAP_SYS_ADMIN))
2283 if (file->f_op->write == redirected_tty_write) {
2285 spin_lock(&redirect_lock);
2288 spin_unlock(&redirect_lock);
2293 spin_lock(&redirect_lock);
2295 spin_unlock(&redirect_lock);
2298 redirect = get_file(file);
2299 spin_unlock(&redirect_lock);
2304 * fionbio - non blocking ioctl
2305 * @file: file to set blocking value
2306 * @p: user parameter
2308 * Historical tty interfaces had a blocking control ioctl before
2309 * the generic functionality existed. This piece of history is preserved
2310 * in the expected tty API of posix OS's.
2312 * Locking: none, the open file handle ensures it won't go away.
2315 static int fionbio(struct file *file, int __user *p)
2319 if (get_user(nonblock, p))
2322 spin_lock(&file->f_lock);
2324 file->f_flags |= O_NONBLOCK;
2326 file->f_flags &= ~O_NONBLOCK;
2327 spin_unlock(&file->f_lock);
2332 * tiocsetd - set line discipline
2334 * @p: pointer to user data
2336 * Set the line discipline according to user request.
2338 * Locking: see tty_set_ldisc, this function is just a helper
2341 static int tiocsetd(struct tty_struct *tty, int __user *p)
2346 if (get_user(disc, p))
2349 ret = tty_set_ldisc(tty, disc);
2355 * tiocgetd - get line discipline
2357 * @p: pointer to user data
2359 * Retrieves the line discipline id directly from the ldisc.
2361 * Locking: waits for ldisc reference (in case the line discipline
2362 * is changing or the tty is being hungup)
2365 static int tiocgetd(struct tty_struct *tty, int __user *p)
2367 struct tty_ldisc *ld;
2370 ld = tty_ldisc_ref_wait(tty);
2373 ret = put_user(ld->ops->num, p);
2374 tty_ldisc_deref(ld);
2379 * send_break - performed time break
2380 * @tty: device to break on
2381 * @duration: timeout in mS
2383 * Perform a timed break on hardware that lacks its own driver level
2384 * timed break functionality.
2387 * atomic_write_lock serializes
2391 static int send_break(struct tty_struct *tty, unsigned int duration)
2395 if (tty->ops->break_ctl == NULL)
2398 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2399 retval = tty->ops->break_ctl(tty, duration);
2401 /* Do the work ourselves */
2402 if (tty_write_lock(tty, 0) < 0)
2404 retval = tty->ops->break_ctl(tty, -1);
2407 if (!signal_pending(current))
2408 msleep_interruptible(duration);
2409 retval = tty->ops->break_ctl(tty, 0);
2411 tty_write_unlock(tty);
2412 if (signal_pending(current))
2419 * tty_tiocmget - get modem status
2421 * @file: user file pointer
2422 * @p: pointer to result
2424 * Obtain the modem status bits from the tty driver if the feature
2425 * is supported. Return -EINVAL if it is not available.
2427 * Locking: none (up to the driver)
2430 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2432 int retval = -EINVAL;
2434 if (tty->ops->tiocmget) {
2435 retval = tty->ops->tiocmget(tty);
2438 retval = put_user(retval, p);
2444 * tty_tiocmset - set modem status
2446 * @cmd: command - clear bits, set bits or set all
2447 * @p: pointer to desired bits
2449 * Set the modem status bits from the tty driver if the feature
2450 * is supported. Return -EINVAL if it is not available.
2452 * Locking: none (up to the driver)
2455 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2459 unsigned int set, clear, val;
2461 if (tty->ops->tiocmset == NULL)
2464 retval = get_user(val, p);
2480 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2481 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2482 return tty->ops->tiocmset(tty, set, clear);
2485 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2487 int retval = -EINVAL;
2488 struct serial_icounter_struct icount;
2489 memset(&icount, 0, sizeof(icount));
2490 if (tty->ops->get_icount)
2491 retval = tty->ops->get_icount(tty, &icount);
2494 if (copy_to_user(arg, &icount, sizeof(icount)))
2499 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2501 static DEFINE_RATELIMIT_STATE(depr_flags,
2502 DEFAULT_RATELIMIT_INTERVAL,
2503 DEFAULT_RATELIMIT_BURST);
2504 char comm[TASK_COMM_LEN];
2507 if (get_user(flags, &ss->flags))
2510 flags &= ASYNC_DEPRECATED;
2512 if (flags && __ratelimit(&depr_flags))
2513 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2514 __func__, get_task_comm(comm, current), flags);
2518 * if pty, return the slave side (real_tty)
2519 * otherwise, return self
2521 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2523 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2524 tty->driver->subtype == PTY_TYPE_MASTER)
2530 * Split this up, as gcc can choke on it otherwise..
2532 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2534 struct tty_struct *tty = file_tty(file);
2535 struct tty_struct *real_tty;
2536 void __user *p = (void __user *)arg;
2538 struct tty_ldisc *ld;
2540 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2543 real_tty = tty_pair_get_tty(tty);
2546 * Factor out some common prep work
2554 retval = tty_check_change(tty);
2557 if (cmd != TIOCCBRK) {
2558 tty_wait_until_sent(tty, 0);
2559 if (signal_pending(current))
2570 return tiocsti(tty, p);
2572 return tiocgwinsz(real_tty, p);
2574 return tiocswinsz(real_tty, p);
2576 return real_tty != tty ? -EINVAL : tioccons(file);
2578 return fionbio(file, p);
2580 set_bit(TTY_EXCLUSIVE, &tty->flags);
2583 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2587 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2588 return put_user(excl, (int __user *)p);
2591 return tiocgetd(tty, p);
2593 return tiocsetd(tty, p);
2595 if (!capable(CAP_SYS_ADMIN))
2601 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2602 return put_user(ret, (unsigned int __user *)p);
2607 case TIOCSBRK: /* Turn break on, unconditionally */
2608 if (tty->ops->break_ctl)
2609 return tty->ops->break_ctl(tty, -1);
2611 case TIOCCBRK: /* Turn break off, unconditionally */
2612 if (tty->ops->break_ctl)
2613 return tty->ops->break_ctl(tty, 0);
2615 case TCSBRK: /* SVID version: non-zero arg --> no break */
2616 /* non-zero arg means wait for all output data
2617 * to be sent (performed above) but don't send break.
2618 * This is used by the tcdrain() termios function.
2621 return send_break(tty, 250);
2623 case TCSBRKP: /* support for POSIX tcsendbreak() */
2624 return send_break(tty, arg ? arg*100 : 250);
2627 return tty_tiocmget(tty, p);
2631 return tty_tiocmset(tty, cmd, p);
2633 retval = tty_tiocgicount(tty, p);
2634 /* For the moment allow fall through to the old method */
2635 if (retval != -EINVAL)
2642 /* flush tty buffer and allow ldisc to process ioctl */
2643 tty_buffer_flush(tty, NULL);
2648 tty_warn_deprecated_flags(p);
2651 /* Special because the struct file is needed */
2652 return ptm_open_peer(file, tty, (int)arg);
2654 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2655 if (retval != -ENOIOCTLCMD)
2658 if (tty->ops->ioctl) {
2659 retval = tty->ops->ioctl(tty, cmd, arg);
2660 if (retval != -ENOIOCTLCMD)
2663 ld = tty_ldisc_ref_wait(tty);
2665 return hung_up_tty_ioctl(file, cmd, arg);
2667 if (ld->ops->ioctl) {
2668 retval = ld->ops->ioctl(tty, file, cmd, arg);
2669 if (retval == -ENOIOCTLCMD)
2672 tty_ldisc_deref(ld);
2676 #ifdef CONFIG_COMPAT
2677 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2680 struct tty_struct *tty = file_tty(file);
2681 struct tty_ldisc *ld;
2682 int retval = -ENOIOCTLCMD;
2684 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2687 if (tty->ops->compat_ioctl) {
2688 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2689 if (retval != -ENOIOCTLCMD)
2693 ld = tty_ldisc_ref_wait(tty);
2695 return hung_up_tty_compat_ioctl(file, cmd, arg);
2696 if (ld->ops->compat_ioctl)
2697 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2699 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2700 tty_ldisc_deref(ld);
2706 static int this_tty(const void *t, struct file *file, unsigned fd)
2708 if (likely(file->f_op->read != tty_read))
2710 return file_tty(file) != t ? 0 : fd + 1;
2714 * This implements the "Secure Attention Key" --- the idea is to
2715 * prevent trojan horses by killing all processes associated with this
2716 * tty when the user hits the "Secure Attention Key". Required for
2717 * super-paranoid applications --- see the Orange Book for more details.
2719 * This code could be nicer; ideally it should send a HUP, wait a few
2720 * seconds, then send a INT, and then a KILL signal. But you then
2721 * have to coordinate with the init process, since all processes associated
2722 * with the current tty must be dead before the new getty is allowed
2725 * Now, if it would be correct ;-/ The current code has a nasty hole -
2726 * it doesn't catch files in flight. We may send the descriptor to ourselves
2727 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2729 * Nasty bug: do_SAK is being called in interrupt context. This can
2730 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2732 void __do_SAK(struct tty_struct *tty)
2737 struct task_struct *g, *p;
2738 struct pid *session;
2743 session = tty->session;
2745 tty_ldisc_flush(tty);
2747 tty_driver_flush_buffer(tty);
2749 read_lock(&tasklist_lock);
2750 /* Kill the entire session */
2751 do_each_pid_task(session, PIDTYPE_SID, p) {
2752 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
2753 task_pid_nr(p), p->comm);
2754 send_sig(SIGKILL, p, 1);
2755 } while_each_pid_task(session, PIDTYPE_SID, p);
2757 /* Now kill any processes that happen to have the tty open */
2758 do_each_thread(g, p) {
2759 if (p->signal->tty == tty) {
2760 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
2761 task_pid_nr(p), p->comm);
2762 send_sig(SIGKILL, p, 1);
2766 i = iterate_fd(p->files, 0, this_tty, tty);
2768 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
2769 task_pid_nr(p), p->comm, i - 1);
2770 force_sig(SIGKILL, p);
2773 } while_each_thread(g, p);
2774 read_unlock(&tasklist_lock);
2778 static void do_SAK_work(struct work_struct *work)
2780 struct tty_struct *tty =
2781 container_of(work, struct tty_struct, SAK_work);
2786 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2787 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2788 * the values which we write to it will be identical to the values which it
2789 * already has. --akpm
2791 void do_SAK(struct tty_struct *tty)
2795 schedule_work(&tty->SAK_work);
2798 EXPORT_SYMBOL(do_SAK);
2800 static int dev_match_devt(struct device *dev, const void *data)
2802 const dev_t *devt = data;
2803 return dev->devt == *devt;
2806 /* Must put_device() after it's unused! */
2807 static struct device *tty_get_device(struct tty_struct *tty)
2809 dev_t devt = tty_devnum(tty);
2810 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2817 * This subroutine allocates and initializes a tty structure.
2819 * Locking: none - tty in question is not exposed at this point
2822 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
2824 struct tty_struct *tty;
2826 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
2830 kref_init(&tty->kref);
2831 tty->magic = TTY_MAGIC;
2832 if (tty_ldisc_init(tty)) {
2836 tty->session = NULL;
2838 mutex_init(&tty->legacy_mutex);
2839 mutex_init(&tty->throttle_mutex);
2840 init_rwsem(&tty->termios_rwsem);
2841 mutex_init(&tty->winsize_mutex);
2842 init_ldsem(&tty->ldisc_sem);
2843 init_waitqueue_head(&tty->write_wait);
2844 init_waitqueue_head(&tty->read_wait);
2845 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2846 mutex_init(&tty->atomic_write_lock);
2847 spin_lock_init(&tty->ctrl_lock);
2848 spin_lock_init(&tty->flow_lock);
2849 spin_lock_init(&tty->files_lock);
2850 INIT_LIST_HEAD(&tty->tty_files);
2851 INIT_WORK(&tty->SAK_work, do_SAK_work);
2853 tty->driver = driver;
2854 tty->ops = driver->ops;
2856 tty_line_name(driver, idx, tty->name);
2857 tty->dev = tty_get_device(tty);
2863 * tty_put_char - write one character to a tty
2867 * Write one byte to the tty using the provided put_char method
2868 * if present. Returns the number of characters successfully output.
2870 * Note: the specific put_char operation in the driver layer may go
2871 * away soon. Don't call it directly, use this method
2874 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2876 if (tty->ops->put_char)
2877 return tty->ops->put_char(tty, ch);
2878 return tty->ops->write(tty, &ch, 1);
2880 EXPORT_SYMBOL_GPL(tty_put_char);
2882 struct class *tty_class;
2884 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
2885 unsigned int index, unsigned int count)
2889 /* init here, since reused cdevs cause crashes */
2890 driver->cdevs[index] = cdev_alloc();
2891 if (!driver->cdevs[index])
2893 driver->cdevs[index]->ops = &tty_fops;
2894 driver->cdevs[index]->owner = driver->owner;
2895 err = cdev_add(driver->cdevs[index], dev, count);
2897 kobject_put(&driver->cdevs[index]->kobj);
2902 * tty_register_device - register a tty device
2903 * @driver: the tty driver that describes the tty device
2904 * @index: the index in the tty driver for this tty device
2905 * @device: a struct device that is associated with this tty device.
2906 * This field is optional, if there is no known struct device
2907 * for this tty device it can be set to NULL safely.
2909 * Returns a pointer to the struct device for this tty device
2910 * (or ERR_PTR(-EFOO) on error).
2912 * This call is required to be made to register an individual tty device
2913 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2914 * that bit is not set, this function should not be called by a tty
2920 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2921 struct device *device)
2923 return tty_register_device_attr(driver, index, device, NULL, NULL);
2925 EXPORT_SYMBOL(tty_register_device);
2927 static void tty_device_create_release(struct device *dev)
2929 dev_dbg(dev, "releasing...\n");
2934 * tty_register_device_attr - register a tty device
2935 * @driver: the tty driver that describes the tty device
2936 * @index: the index in the tty driver for this tty device
2937 * @device: a struct device that is associated with this tty device.
2938 * This field is optional, if there is no known struct device
2939 * for this tty device it can be set to NULL safely.
2940 * @drvdata: Driver data to be set to device.
2941 * @attr_grp: Attribute group to be set on device.
2943 * Returns a pointer to the struct device for this tty device
2944 * (or ERR_PTR(-EFOO) on error).
2946 * This call is required to be made to register an individual tty device
2947 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2948 * that bit is not set, this function should not be called by a tty
2953 struct device *tty_register_device_attr(struct tty_driver *driver,
2954 unsigned index, struct device *device,
2956 const struct attribute_group **attr_grp)
2959 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
2960 struct ktermios *tp;
2964 if (index >= driver->num) {
2965 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
2966 driver->name, index);
2967 return ERR_PTR(-EINVAL);
2970 if (driver->type == TTY_DRIVER_TYPE_PTY)
2971 pty_line_name(driver, index, name);
2973 tty_line_name(driver, index, name);
2975 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2977 return ERR_PTR(-ENOMEM);
2980 dev->class = tty_class;
2981 dev->parent = device;
2982 dev->release = tty_device_create_release;
2983 dev_set_name(dev, "%s", name);
2984 dev->groups = attr_grp;
2985 dev_set_drvdata(dev, drvdata);
2987 dev_set_uevent_suppress(dev, 1);
2989 retval = device_register(dev);
2993 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
2995 * Free any saved termios data so that the termios state is
2996 * reset when reusing a minor number.
2998 tp = driver->termios[index];
3000 driver->termios[index] = NULL;
3004 retval = tty_cdev_add(driver, devt, index, 1);
3009 dev_set_uevent_suppress(dev, 0);
3010 kobject_uevent(&dev->kobj, KOBJ_ADD);
3019 return ERR_PTR(retval);
3021 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3024 * tty_unregister_device - unregister a tty device
3025 * @driver: the tty driver that describes the tty device
3026 * @index: the index in the tty driver for this tty device
3028 * If a tty device is registered with a call to tty_register_device() then
3029 * this function must be called when the tty device is gone.
3034 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3036 device_destroy(tty_class,
3037 MKDEV(driver->major, driver->minor_start) + index);
3038 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3039 cdev_del(driver->cdevs[index]);
3040 driver->cdevs[index] = NULL;
3043 EXPORT_SYMBOL(tty_unregister_device);
3046 * __tty_alloc_driver -- allocate tty driver
3047 * @lines: count of lines this driver can handle at most
3048 * @owner: module which is responsible for this driver
3049 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3051 * This should not be called directly, some of the provided macros should be
3052 * used instead. Use IS_ERR and friends on @retval.
3054 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3055 unsigned long flags)
3057 struct tty_driver *driver;
3058 unsigned int cdevs = 1;
3061 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3062 return ERR_PTR(-EINVAL);
3064 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3066 return ERR_PTR(-ENOMEM);
3068 kref_init(&driver->kref);
3069 driver->magic = TTY_DRIVER_MAGIC;
3070 driver->num = lines;
3071 driver->owner = owner;
3072 driver->flags = flags;
3074 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3075 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3077 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3079 if (!driver->ttys || !driver->termios) {
3085 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3086 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3088 if (!driver->ports) {
3095 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3096 if (!driver->cdevs) {
3103 kfree(driver->ports);
3104 kfree(driver->ttys);
3105 kfree(driver->termios);
3106 kfree(driver->cdevs);
3108 return ERR_PTR(err);
3110 EXPORT_SYMBOL(__tty_alloc_driver);
3112 static void destruct_tty_driver(struct kref *kref)
3114 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3116 struct ktermios *tp;
3118 if (driver->flags & TTY_DRIVER_INSTALLED) {
3119 for (i = 0; i < driver->num; i++) {
3120 tp = driver->termios[i];
3122 driver->termios[i] = NULL;
3125 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3126 tty_unregister_device(driver, i);
3128 proc_tty_unregister_driver(driver);
3129 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3130 cdev_del(driver->cdevs[0]);
3132 kfree(driver->cdevs);
3133 kfree(driver->ports);
3134 kfree(driver->termios);
3135 kfree(driver->ttys);
3139 void tty_driver_kref_put(struct tty_driver *driver)
3141 kref_put(&driver->kref, destruct_tty_driver);
3143 EXPORT_SYMBOL(tty_driver_kref_put);
3145 void tty_set_operations(struct tty_driver *driver,
3146 const struct tty_operations *op)
3150 EXPORT_SYMBOL(tty_set_operations);
3152 void put_tty_driver(struct tty_driver *d)
3154 tty_driver_kref_put(d);
3156 EXPORT_SYMBOL(put_tty_driver);
3159 * Called by a tty driver to register itself.
3161 int tty_register_driver(struct tty_driver *driver)
3168 if (!driver->major) {
3169 error = alloc_chrdev_region(&dev, driver->minor_start,
3170 driver->num, driver->name);
3172 driver->major = MAJOR(dev);
3173 driver->minor_start = MINOR(dev);
3176 dev = MKDEV(driver->major, driver->minor_start);
3177 error = register_chrdev_region(dev, driver->num, driver->name);
3182 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3183 error = tty_cdev_add(driver, dev, 0, driver->num);
3185 goto err_unreg_char;
3188 mutex_lock(&tty_mutex);
3189 list_add(&driver->tty_drivers, &tty_drivers);
3190 mutex_unlock(&tty_mutex);
3192 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3193 for (i = 0; i < driver->num; i++) {
3194 d = tty_register_device(driver, i, NULL);
3197 goto err_unreg_devs;
3201 proc_tty_register_driver(driver);
3202 driver->flags |= TTY_DRIVER_INSTALLED;
3206 for (i--; i >= 0; i--)
3207 tty_unregister_device(driver, i);
3209 mutex_lock(&tty_mutex);
3210 list_del(&driver->tty_drivers);
3211 mutex_unlock(&tty_mutex);
3214 unregister_chrdev_region(dev, driver->num);
3218 EXPORT_SYMBOL(tty_register_driver);
3221 * Called by a tty driver to unregister itself.
3223 int tty_unregister_driver(struct tty_driver *driver)
3227 if (driver->refcount)
3230 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3232 mutex_lock(&tty_mutex);
3233 list_del(&driver->tty_drivers);
3234 mutex_unlock(&tty_mutex);
3238 EXPORT_SYMBOL(tty_unregister_driver);
3240 dev_t tty_devnum(struct tty_struct *tty)
3242 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3244 EXPORT_SYMBOL(tty_devnum);
3246 void tty_default_fops(struct file_operations *fops)
3251 static char *tty_devnode(struct device *dev, umode_t *mode)
3255 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3256 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3261 static int __init tty_class_init(void)
3263 tty_class = class_create(THIS_MODULE, "tty");
3264 if (IS_ERR(tty_class))
3265 return PTR_ERR(tty_class);
3266 tty_class->devnode = tty_devnode;
3270 postcore_initcall(tty_class_init);
3272 /* 3/2004 jmc: why do these devices exist? */
3273 static struct cdev tty_cdev, console_cdev;
3275 static ssize_t show_cons_active(struct device *dev,
3276 struct device_attribute *attr, char *buf)
3278 struct console *cs[16];
3284 for_each_console(c) {
3289 if ((c->flags & CON_ENABLED) == 0)
3292 if (i >= ARRAY_SIZE(cs))
3296 int index = cs[i]->index;
3297 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3299 /* don't resolve tty0 as some programs depend on it */
3300 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3301 count += tty_line_name(drv, index, buf + count);
3303 count += sprintf(buf + count, "%s%d",
3304 cs[i]->name, cs[i]->index);
3306 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3312 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3314 static struct attribute *cons_dev_attrs[] = {
3315 &dev_attr_active.attr,
3319 ATTRIBUTE_GROUPS(cons_dev);
3321 static struct device *consdev;
3323 void console_sysfs_notify(void)
3326 sysfs_notify(&consdev->kobj, NULL, "active");
3330 * Ok, now we can initialize the rest of the tty devices and can count
3331 * on memory allocations, interrupts etc..
3333 int __init tty_init(void)
3335 cdev_init(&tty_cdev, &tty_fops);
3336 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3337 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3338 panic("Couldn't register /dev/tty driver\n");
3339 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3341 cdev_init(&console_cdev, &console_fops);
3342 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3343 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3344 panic("Couldn't register /dev/console driver\n");
3345 consdev = device_create_with_groups(tty_class, NULL,
3346 MKDEV(TTYAUX_MAJOR, 1), NULL,
3347 cons_dev_groups, "console");
3348 if (IS_ERR(consdev))
3352 vty_init(&console_fops);