1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
8 * or rs-channels. It also implements echoing, cooked mode etc.
10 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
12 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
13 * tty_struct and tty_queue structures. Previously there was an array
14 * of 256 tty_struct's which was statically allocated, and the
15 * tty_queue structures were allocated at boot time. Both are now
16 * dynamically allocated only when the tty is open.
18 * Also restructured routines so that there is more of a separation
19 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
20 * the low-level tty routines (serial.c, pty.c, console.c). This
21 * makes for cleaner and more compact code. -TYT, 9/17/92
23 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
24 * which can be dynamically activated and de-activated by the line
25 * discipline handling modules (like SLIP).
27 * NOTE: pay no attention to the line discipline code (yet); its
28 * interface is still subject to change in this version...
31 * Added functionality to the OPOST tty handling. No delays, but all
32 * other bits should be there.
33 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
35 * Rewrote canonical mode and added more termios flags.
36 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
38 * Reorganized FASYNC support so mouse code can share it.
39 * -- ctm@ardi.com, 9Sep95
41 * New TIOCLINUX variants added.
42 * -- mj@k332.feld.cvut.cz, 19-Nov-95
44 * Restrict vt switching via ioctl()
45 * -- grif@cs.ucr.edu, 5-Dec-95
47 * Move console and virtual terminal code to more appropriate files,
48 * implement CONFIG_VT and generalize console device interface.
49 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
51 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
52 * -- Bill Hawes <whawes@star.net>, June 97
54 * Added devfs support.
55 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
57 * Added support for a Unix98-style ptmx device.
58 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
60 * Reduced memory usage for older ARM systems
61 * -- Russell King <rmk@arm.linux.org.uk>
63 * Move do_SAK() into process context. Less stack use in devfs functions.
64 * alloc_tty_struct() always uses kmalloc()
65 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
68 #include <linux/types.h>
69 #include <linux/major.h>
70 #include <linux/errno.h>
71 #include <linux/signal.h>
72 #include <linux/fcntl.h>
73 #include <linux/sched/signal.h>
74 #include <linux/sched/task.h>
75 #include <linux/interrupt.h>
76 #include <linux/tty.h>
77 #include <linux/tty_driver.h>
78 #include <linux/tty_flip.h>
79 #include <linux/devpts_fs.h>
80 #include <linux/file.h>
81 #include <linux/fdtable.h>
82 #include <linux/console.h>
83 #include <linux/timer.h>
84 #include <linux/ctype.h>
87 #include <linux/string.h>
88 #include <linux/slab.h>
89 #include <linux/poll.h>
90 #include <linux/ppp-ioctl.h>
91 #include <linux/proc_fs.h>
92 #include <linux/init.h>
93 #include <linux/module.h>
94 #include <linux/device.h>
95 #include <linux/wait.h>
96 #include <linux/bitops.h>
97 #include <linux/delay.h>
98 #include <linux/seq_file.h>
99 #include <linux/serial.h>
100 #include <linux/ratelimit.h>
101 #include <linux/compat.h>
103 #include <linux/uaccess.h>
105 #include <linux/kbd_kern.h>
106 #include <linux/vt_kern.h>
107 #include <linux/selection.h>
109 #include <linux/kmod.h>
110 #include <linux/nsproxy.h>
113 #undef TTY_DEBUG_HANGUP
114 #ifdef TTY_DEBUG_HANGUP
115 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
117 # define tty_debug_hangup(tty, f, args...) do { } while (0)
120 #define TTY_PARANOIA_CHECK 1
121 #define CHECK_TTY_COUNT 1
123 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
124 .c_iflag = ICRNL | IXON,
125 .c_oflag = OPOST | ONLCR,
126 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
127 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
128 ECHOCTL | ECHOKE | IEXTEN,
132 /* .c_line = N_TTY, */
135 EXPORT_SYMBOL(tty_std_termios);
137 /* This list gets poked at by procfs and various bits of boot up code. This
138 could do with some rationalisation such as pulling the tty proc function
141 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
143 /* Mutex to protect creating and releasing a tty */
144 DEFINE_MUTEX(tty_mutex);
146 static ssize_t tty_read(struct kiocb *, struct iov_iter *);
147 static ssize_t tty_write(struct kiocb *, struct iov_iter *);
148 static __poll_t tty_poll(struct file *, poll_table *);
149 static int tty_open(struct inode *, struct file *);
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 * @device: 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 (!len || 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 kiocb *iocb, struct iov_iter *to)
438 static ssize_t hung_up_tty_write(struct kiocb *iocb, struct iov_iter *from)
443 /* No kernel lock held - none needed ;) */
444 static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
446 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
449 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
452 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
455 static long hung_up_tty_compat_ioctl(struct file *file,
456 unsigned int cmd, unsigned long arg)
458 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
461 static int hung_up_tty_fasync(int fd, struct file *file, int on)
466 static void tty_show_fdinfo(struct seq_file *m, struct file *file)
468 struct tty_struct *tty = file_tty(file);
470 if (tty && tty->ops && tty->ops->show_fdinfo)
471 tty->ops->show_fdinfo(tty, m);
474 static const struct file_operations tty_fops = {
476 .read_iter = tty_read,
477 .write_iter = tty_write,
478 .splice_read = generic_file_splice_read,
479 .splice_write = iter_file_splice_write,
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 = {
491 .read_iter = tty_read,
492 .write_iter = redirected_tty_write,
493 .splice_read = generic_file_splice_read,
494 .splice_write = iter_file_splice_write,
496 .unlocked_ioctl = tty_ioctl,
497 .compat_ioctl = tty_compat_ioctl,
499 .release = tty_release,
500 .fasync = tty_fasync,
503 static const struct file_operations hung_up_tty_fops = {
505 .read_iter = hung_up_tty_read,
506 .write_iter = hung_up_tty_write,
507 .poll = hung_up_tty_poll,
508 .unlocked_ioctl = hung_up_tty_ioctl,
509 .compat_ioctl = hung_up_tty_compat_ioctl,
510 .release = tty_release,
511 .fasync = hung_up_tty_fasync,
514 static DEFINE_SPINLOCK(redirect_lock);
515 static struct file *redirect;
517 extern void tty_sysctl_init(void);
520 * tty_wakeup - request more data
523 * Internal and external helper for wakeups of tty. This function
524 * informs the line discipline if present that the driver is ready
525 * to receive more output data.
528 void tty_wakeup(struct tty_struct *tty)
530 struct tty_ldisc *ld;
532 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
533 ld = tty_ldisc_ref(tty);
535 if (ld->ops->write_wakeup)
536 ld->ops->write_wakeup(tty);
540 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
543 EXPORT_SYMBOL_GPL(tty_wakeup);
546 * __tty_hangup - actual handler for hangup events
549 * This can be called by a "kworker" kernel thread. That is process
550 * synchronous but doesn't hold any locks, so we need to make sure we
551 * have the appropriate locks for what we're doing.
553 * The hangup event clears any pending redirections onto the hung up
554 * device. It ensures future writes will error and it does the needed
555 * line discipline hangup and signal delivery. The tty object itself
560 * redirect lock for undoing redirection
561 * file list lock for manipulating list of ttys
562 * tty_ldiscs_lock from called functions
563 * termios_rwsem resetting termios data
564 * tasklist_lock to walk task list for hangup event
565 * ->siglock to protect ->signal/->sighand
567 static void __tty_hangup(struct tty_struct *tty, int exit_session)
569 struct file *cons_filp = NULL;
570 struct file *filp, *f = NULL;
571 struct tty_file_private *priv;
572 int closecount = 0, n;
579 spin_lock(&redirect_lock);
580 if (redirect && file_tty(redirect) == tty) {
584 spin_unlock(&redirect_lock);
588 if (test_bit(TTY_HUPPED, &tty->flags)) {
594 * Some console devices aren't actually hung up for technical and
595 * historical reasons, which can lead to indefinite interruptible
596 * sleep in n_tty_read(). The following explicitly tells
597 * n_tty_read() to abort readers.
599 set_bit(TTY_HUPPING, &tty->flags);
601 /* inuse_filps is protected by the single tty lock,
602 this really needs to change if we want to flush the
603 workqueue with the lock held */
604 check_tty_count(tty, "tty_hangup");
606 spin_lock(&tty->files_lock);
607 /* This breaks for file handles being sent over AF_UNIX sockets ? */
608 list_for_each_entry(priv, &tty->tty_files, list) {
610 if (filp->f_op->write_iter == redirected_tty_write)
612 if (filp->f_op->write_iter != tty_write)
615 __tty_fasync(-1, filp, 0); /* can't block */
616 filp->f_op = &hung_up_tty_fops;
618 spin_unlock(&tty->files_lock);
620 refs = tty_signal_session_leader(tty, exit_session);
621 /* Account for the p->signal references we killed */
625 tty_ldisc_hangup(tty, cons_filp != NULL);
627 spin_lock_irq(&tty->ctrl_lock);
628 clear_bit(TTY_THROTTLED, &tty->flags);
629 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
630 put_pid(tty->session);
634 tty->ctrl_status = 0;
635 spin_unlock_irq(&tty->ctrl_lock);
638 * If one of the devices matches a console pointer, we
639 * cannot just call hangup() because that will cause
640 * tty->count and state->count to go out of sync.
641 * So we just call close() the right number of times.
645 for (n = 0; n < closecount; n++)
646 tty->ops->close(tty, cons_filp);
647 } else if (tty->ops->hangup)
648 tty->ops->hangup(tty);
650 * We don't want to have driver/ldisc interactions beyond the ones
651 * we did here. The driver layer expects no calls after ->hangup()
652 * from the ldisc side, which is now guaranteed.
654 set_bit(TTY_HUPPED, &tty->flags);
655 clear_bit(TTY_HUPPING, &tty->flags);
662 static void do_tty_hangup(struct work_struct *work)
664 struct tty_struct *tty =
665 container_of(work, struct tty_struct, hangup_work);
667 __tty_hangup(tty, 0);
671 * tty_hangup - trigger a hangup event
672 * @tty: tty to hangup
674 * A carrier loss (virtual or otherwise) has occurred on this like
675 * schedule a hangup sequence to run after this event.
678 void tty_hangup(struct tty_struct *tty)
680 tty_debug_hangup(tty, "hangup\n");
681 schedule_work(&tty->hangup_work);
684 EXPORT_SYMBOL(tty_hangup);
687 * tty_vhangup - process vhangup
688 * @tty: tty to hangup
690 * The user has asked via system call for the terminal to be hung up.
691 * We do this synchronously so that when the syscall returns the process
692 * is complete. That guarantee is necessary for security reasons.
695 void tty_vhangup(struct tty_struct *tty)
697 tty_debug_hangup(tty, "vhangup\n");
698 __tty_hangup(tty, 0);
701 EXPORT_SYMBOL(tty_vhangup);
705 * tty_vhangup_self - process vhangup for own ctty
707 * Perform a vhangup on the current controlling tty
710 void tty_vhangup_self(void)
712 struct tty_struct *tty;
714 tty = get_current_tty();
722 * tty_vhangup_session - hangup session leader exit
723 * @tty: tty to hangup
725 * The session leader is exiting and hanging up its controlling terminal.
726 * Every process in the foreground process group is signalled SIGHUP.
728 * We do this synchronously so that when the syscall returns the process
729 * is complete. That guarantee is necessary for security reasons.
732 void tty_vhangup_session(struct tty_struct *tty)
734 tty_debug_hangup(tty, "session hangup\n");
735 __tty_hangup(tty, 1);
739 * tty_hung_up_p - was tty hung up
740 * @filp: file pointer of tty
742 * Return true if the tty has been subject to a vhangup or a carrier
746 int tty_hung_up_p(struct file *filp)
748 return (filp && filp->f_op == &hung_up_tty_fops);
751 EXPORT_SYMBOL(tty_hung_up_p);
754 * stop_tty - propagate flow control
757 * Perform flow control to the driver. May be called
758 * on an already stopped device and will not re-call the driver
761 * This functionality is used by both the line disciplines for
762 * halting incoming flow and by the driver. It may therefore be
763 * called from any context, may be under the tty atomic_write_lock
770 void __stop_tty(struct tty_struct *tty)
779 void stop_tty(struct tty_struct *tty)
783 spin_lock_irqsave(&tty->flow_lock, flags);
785 spin_unlock_irqrestore(&tty->flow_lock, flags);
787 EXPORT_SYMBOL(stop_tty);
790 * start_tty - propagate flow control
793 * Start a tty that has been stopped if at all possible. If this
794 * tty was previous stopped and is now being started, the driver
795 * start method is invoked and the line discipline woken.
801 void __start_tty(struct tty_struct *tty)
803 if (!tty->stopped || tty->flow_stopped)
807 tty->ops->start(tty);
811 void start_tty(struct tty_struct *tty)
815 spin_lock_irqsave(&tty->flow_lock, flags);
817 spin_unlock_irqrestore(&tty->flow_lock, flags);
819 EXPORT_SYMBOL(start_tty);
821 static void tty_update_time(struct timespec64 *time)
823 time64_t sec = ktime_get_real_seconds();
826 * We only care if the two values differ in anything other than the
827 * lower three bits (i.e every 8 seconds). If so, then we can update
828 * the time of the tty device, otherwise it could be construded as a
829 * security leak to let userspace know the exact timing of the tty.
831 if ((sec ^ time->tv_sec) & ~7)
836 * Iterate on the ldisc ->read() function until we've gotten all
837 * the data the ldisc has for us.
839 * The "cookie" is something that the ldisc read function can fill
840 * in to let us know that there is more data to be had.
842 * We promise to continue to call the ldisc until it stops returning
843 * data or clears the cookie. The cookie may be something that the
844 * ldisc maintains state for and needs to free.
846 static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty,
847 struct file *file, struct iov_iter *to)
851 unsigned long offset = 0;
853 size_t count = iov_iter_count(to);
858 size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count;
859 size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset);
864 /* Did we have an earlier error (ie -EFAULT)? */
870 * -EOVERFLOW means we didn't have enough space
871 * for a whole packet, and we shouldn't return
874 if (retval == -EOVERFLOW)
879 copied = copy_to_iter(kernel_buf, size, to);
884 * If the user copy failed, we still need to do another ->read()
885 * call if we had a cookie to let the ldisc clear up.
887 * But make sure size is zeroed.
889 if (unlikely(copied != size)) {
895 /* We always clear tty buffer in case they contained passwords */
896 memzero_explicit(kernel_buf, sizeof(kernel_buf));
897 return offset ? offset : retval;
902 * tty_read - read method for tty device files
903 * @file: pointer to tty file
905 * @count: size of user buffer
908 * Perform the read system call function on this terminal device. Checks
909 * for hung up devices before calling the line discipline method.
912 * Locks the line discipline internally while needed. Multiple
913 * read calls may be outstanding in parallel.
916 static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to)
919 struct file *file = iocb->ki_filp;
920 struct inode *inode = file_inode(file);
921 struct tty_struct *tty = file_tty(file);
922 struct tty_ldisc *ld;
924 if (tty_paranoia_check(tty, inode, "tty_read"))
926 if (!tty || tty_io_error(tty))
929 /* We want to wait for the line discipline to sort out in this
931 ld = tty_ldisc_ref_wait(tty);
933 return hung_up_tty_read(iocb, to);
936 i = iterate_tty_read(ld, tty, file, to);
940 tty_update_time(&inode->i_atime);
945 void tty_write_unlock(struct tty_struct *tty)
947 mutex_unlock(&tty->atomic_write_lock);
948 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
951 int tty_write_lock(struct tty_struct *tty, bool ndelay)
953 if (!mutex_trylock(&tty->atomic_write_lock)) {
956 if (mutex_lock_interruptible(&tty->atomic_write_lock))
963 * Split writes up in sane blocksizes to avoid
964 * denial-of-service type attacks
966 static inline ssize_t do_tty_write(
967 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
968 struct tty_struct *tty,
970 struct iov_iter *from)
972 size_t count = iov_iter_count(from);
973 ssize_t ret, written = 0;
976 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
981 * We chunk up writes into a temporary buffer. This
982 * simplifies low-level drivers immensely, since they
983 * don't have locking issues and user mode accesses.
985 * But if TTY_NO_WRITE_SPLIT is set, we should use a
988 * The default chunk-size is 2kB, because the NTTY
989 * layer has problems with bigger chunks. It will
990 * claim to be able to handle more characters than
993 * FIXME: This can probably go away now except that 64K chunks
994 * are too likely to fail unless switched to vmalloc...
997 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1002 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1003 if (tty->write_cnt < chunk) {
1004 unsigned char *buf_chunk;
1009 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1014 kfree(tty->write_buf);
1015 tty->write_cnt = chunk;
1016 tty->write_buf = buf_chunk;
1019 /* Do the write .. */
1021 size_t size = count;
1026 if (copy_from_iter(tty->write_buf, size, from) != size)
1029 ret = write(tty, file, tty->write_buf, size);
1037 /* FIXME! Have Al check this! */
1039 iov_iter_revert(from, size-ret);
1045 if (signal_pending(current))
1050 tty_update_time(&file_inode(file)->i_mtime);
1054 tty_write_unlock(tty);
1059 * tty_write_message - write a message to a certain tty, not just the console.
1060 * @tty: the destination tty_struct
1061 * @msg: the message to write
1063 * This is used for messages that need to be redirected to a specific tty.
1064 * We don't put it into the syslog queue right now maybe in the future if
1067 * We must still hold the BTM and test the CLOSING flag for the moment.
1070 void tty_write_message(struct tty_struct *tty, char *msg)
1073 mutex_lock(&tty->atomic_write_lock);
1075 if (tty->ops->write && tty->count > 0)
1076 tty->ops->write(tty, msg, strlen(msg));
1078 tty_write_unlock(tty);
1085 * tty_write - write method for tty device file
1086 * @file: tty file pointer
1087 * @buf: user data to write
1088 * @count: bytes to write
1091 * Write data to a tty device via the line discipline.
1094 * Locks the line discipline as required
1095 * Writes to the tty driver are serialized by the atomic_write_lock
1096 * and are then processed in chunks to the device. The line discipline
1097 * write method will not be invoked in parallel for each device.
1100 static ssize_t file_tty_write(struct file *file, struct kiocb *iocb, struct iov_iter *from)
1102 struct tty_struct *tty = file_tty(file);
1103 struct tty_ldisc *ld;
1106 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1108 if (!tty || !tty->ops->write || tty_io_error(tty))
1110 /* Short term debug to catch buggy drivers */
1111 if (tty->ops->write_room == NULL)
1112 tty_err(tty, "missing write_room method\n");
1113 ld = tty_ldisc_ref_wait(tty);
1115 return hung_up_tty_write(iocb, from);
1116 if (!ld->ops->write)
1119 ret = do_tty_write(ld->ops->write, tty, file, from);
1120 tty_ldisc_deref(ld);
1124 static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from)
1126 return file_tty_write(iocb->ki_filp, iocb, from);
1129 ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter)
1131 struct file *p = NULL;
1133 spin_lock(&redirect_lock);
1135 p = get_file(redirect);
1136 spin_unlock(&redirect_lock);
1139 * We know the redirected tty is just another tty, we can can
1140 * call file_tty_write() directly with that file pointer.
1144 res = file_tty_write(p, iocb, iter);
1148 return tty_write(iocb, iter);
1152 * tty_send_xchar - send priority character
1154 * Send a high priority character to the tty even if stopped
1156 * Locking: none for xchar method, write ordering for write method.
1159 int tty_send_xchar(struct tty_struct *tty, char ch)
1161 int was_stopped = tty->stopped;
1163 if (tty->ops->send_xchar) {
1164 down_read(&tty->termios_rwsem);
1165 tty->ops->send_xchar(tty, ch);
1166 up_read(&tty->termios_rwsem);
1170 if (tty_write_lock(tty, false) < 0)
1171 return -ERESTARTSYS;
1173 down_read(&tty->termios_rwsem);
1176 tty->ops->write(tty, &ch, 1);
1179 up_read(&tty->termios_rwsem);
1180 tty_write_unlock(tty);
1184 static char ptychar[] = "pqrstuvwxyzabcde";
1187 * pty_line_name - generate name for a pty
1188 * @driver: the tty driver in use
1189 * @index: the minor number
1190 * @p: output buffer of at least 6 bytes
1192 * Generate a name from a driver reference and write it to the output
1197 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1199 int i = index + driver->name_base;
1200 /* ->name is initialized to "ttyp", but "tty" is expected */
1201 sprintf(p, "%s%c%x",
1202 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1203 ptychar[i >> 4 & 0xf], i & 0xf);
1207 * tty_line_name - generate name for a tty
1208 * @driver: the tty driver in use
1209 * @index: the minor number
1210 * @p: output buffer of at least 7 bytes
1212 * Generate a name from a driver reference and write it to the output
1217 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1219 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1220 return sprintf(p, "%s", driver->name);
1222 return sprintf(p, "%s%d", driver->name,
1223 index + driver->name_base);
1227 * tty_driver_lookup_tty() - find an existing tty, if any
1228 * @driver: the driver for the tty
1229 * @idx: the minor number
1231 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1232 * driver lookup() method returns an error.
1234 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1236 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1237 struct file *file, int idx)
1239 struct tty_struct *tty;
1241 if (driver->ops->lookup) {
1243 tty = ERR_PTR(-EIO);
1245 tty = driver->ops->lookup(driver, file, idx);
1247 if (idx >= driver->num)
1248 return ERR_PTR(-EINVAL);
1249 tty = driver->ttys[idx];
1257 * tty_init_termios - helper for termios setup
1258 * @tty: the tty to set up
1260 * Initialise the termios structure for this tty. This runs under
1261 * the tty_mutex currently so we can be relaxed about ordering.
1264 void tty_init_termios(struct tty_struct *tty)
1266 struct ktermios *tp;
1267 int idx = tty->index;
1269 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1270 tty->termios = tty->driver->init_termios;
1272 /* Check for lazy saved data */
1273 tp = tty->driver->termios[idx];
1276 tty->termios.c_line = tty->driver->init_termios.c_line;
1278 tty->termios = tty->driver->init_termios;
1280 /* Compatibility until drivers always set this */
1281 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1282 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1284 EXPORT_SYMBOL_GPL(tty_init_termios);
1286 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1288 tty_init_termios(tty);
1289 tty_driver_kref_get(driver);
1291 driver->ttys[tty->index] = tty;
1294 EXPORT_SYMBOL_GPL(tty_standard_install);
1297 * tty_driver_install_tty() - install a tty entry in the driver
1298 * @driver: the driver for the tty
1301 * Install a tty object into the driver tables. The tty->index field
1302 * will be set by the time this is called. This method is responsible
1303 * for ensuring any need additional structures are allocated and
1306 * Locking: tty_mutex for now
1308 static int tty_driver_install_tty(struct tty_driver *driver,
1309 struct tty_struct *tty)
1311 return driver->ops->install ? driver->ops->install(driver, tty) :
1312 tty_standard_install(driver, tty);
1316 * tty_driver_remove_tty() - remove a tty from the driver tables
1317 * @driver: the driver for the tty
1318 * @tty: tty to remove
1320 * Remvoe a tty object from the driver tables. The tty->index field
1321 * will be set by the time this is called.
1323 * Locking: tty_mutex for now
1325 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1327 if (driver->ops->remove)
1328 driver->ops->remove(driver, tty);
1330 driver->ttys[tty->index] = NULL;
1334 * tty_reopen() - fast re-open of an open tty
1335 * @tty: the tty to open
1337 * Return 0 on success, -errno on error.
1338 * Re-opens on master ptys are not allowed and return -EIO.
1340 * Locking: Caller must hold tty_lock
1342 static int tty_reopen(struct tty_struct *tty)
1344 struct tty_driver *driver = tty->driver;
1345 struct tty_ldisc *ld;
1348 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1349 driver->subtype == PTY_TYPE_MASTER)
1355 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1358 ld = tty_ldisc_ref_wait(tty);
1360 tty_ldisc_deref(ld);
1362 retval = tty_ldisc_lock(tty, 5 * HZ);
1367 retval = tty_ldisc_reinit(tty, tty->termios.c_line);
1368 tty_ldisc_unlock(tty);
1378 * tty_init_dev - initialise a tty device
1379 * @driver: tty driver we are opening a device on
1380 * @idx: device index
1382 * Prepare a tty device. This may not be a "new" clean device but
1383 * could also be an active device. The pty drivers require special
1384 * handling because of this.
1387 * The function is called under the tty_mutex, which
1388 * protects us from the tty struct or driver itself going away.
1390 * On exit the tty device has the line discipline attached and
1391 * a reference count of 1. If a pair was created for pty/tty use
1392 * and the other was a pty master then it too has a reference count of 1.
1394 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1395 * failed open. The new code protects the open with a mutex, so it's
1396 * really quite straightforward. The mutex locking can probably be
1397 * relaxed for the (most common) case of reopening a tty.
1399 * Return: returned tty structure
1402 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1404 struct tty_struct *tty;
1408 * First time open is complex, especially for PTY devices.
1409 * This code guarantees that either everything succeeds and the
1410 * TTY is ready for operation, or else the table slots are vacated
1411 * and the allocated memory released. (Except that the termios
1415 if (!try_module_get(driver->owner))
1416 return ERR_PTR(-ENODEV);
1418 tty = alloc_tty_struct(driver, idx);
1421 goto err_module_put;
1425 retval = tty_driver_install_tty(driver, tty);
1430 tty->port = driver->ports[idx];
1432 if (WARN_RATELIMIT(!tty->port,
1433 "%s: %s driver does not set tty->port. This would crash the kernel. Fix the driver!\n",
1434 __func__, tty->driver->name)) {
1436 goto err_release_lock;
1439 retval = tty_ldisc_lock(tty, 5 * HZ);
1441 goto err_release_lock;
1442 tty->port->itty = tty;
1445 * Structures all installed ... call the ldisc open routines.
1446 * If we fail here just call release_tty to clean up. No need
1447 * to decrement the use counts, as release_tty doesn't care.
1449 retval = tty_ldisc_setup(tty, tty->link);
1451 goto err_release_tty;
1452 tty_ldisc_unlock(tty);
1453 /* Return the tty locked so that it cannot vanish under the caller */
1458 free_tty_struct(tty);
1460 module_put(driver->owner);
1461 return ERR_PTR(retval);
1463 /* call the tty release_tty routine to clean out this slot */
1465 tty_ldisc_unlock(tty);
1466 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1470 release_tty(tty, idx);
1471 return ERR_PTR(retval);
1475 * tty_save_termios() - save tty termios data in driver table
1476 * @tty: tty whose termios data to save
1478 * Locking: Caller guarantees serialisation with tty_init_termios().
1480 void tty_save_termios(struct tty_struct *tty)
1482 struct ktermios *tp;
1483 int idx = tty->index;
1485 /* If the port is going to reset then it has no termios to save */
1486 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1489 /* Stash the termios data */
1490 tp = tty->driver->termios[idx];
1492 tp = kmalloc(sizeof(*tp), GFP_KERNEL);
1495 tty->driver->termios[idx] = tp;
1499 EXPORT_SYMBOL_GPL(tty_save_termios);
1502 * tty_flush_works - flush all works of a tty/pty pair
1503 * @tty: tty device to flush works for (or either end of a pty pair)
1505 * Sync flush all works belonging to @tty (and the 'other' tty).
1507 static void tty_flush_works(struct tty_struct *tty)
1509 flush_work(&tty->SAK_work);
1510 flush_work(&tty->hangup_work);
1512 flush_work(&tty->link->SAK_work);
1513 flush_work(&tty->link->hangup_work);
1518 * release_one_tty - release tty structure memory
1519 * @work: work of tty we are obliterating
1521 * Releases memory associated with a tty structure, and clears out the
1522 * driver table slots. This function is called when a device is no longer
1523 * in use. It also gets called when setup of a device fails.
1526 * takes the file list lock internally when working on the list
1527 * of ttys that the driver keeps.
1529 * This method gets called from a work queue so that the driver private
1530 * cleanup ops can sleep (needed for USB at least)
1532 static void release_one_tty(struct work_struct *work)
1534 struct tty_struct *tty =
1535 container_of(work, struct tty_struct, hangup_work);
1536 struct tty_driver *driver = tty->driver;
1537 struct module *owner = driver->owner;
1539 if (tty->ops->cleanup)
1540 tty->ops->cleanup(tty);
1543 tty_driver_kref_put(driver);
1546 spin_lock(&tty->files_lock);
1547 list_del_init(&tty->tty_files);
1548 spin_unlock(&tty->files_lock);
1551 put_pid(tty->session);
1552 free_tty_struct(tty);
1555 static void queue_release_one_tty(struct kref *kref)
1557 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1559 /* The hangup queue is now free so we can reuse it rather than
1560 waste a chunk of memory for each port */
1561 INIT_WORK(&tty->hangup_work, release_one_tty);
1562 schedule_work(&tty->hangup_work);
1566 * tty_kref_put - release a tty kref
1569 * Release a reference to a tty device and if need be let the kref
1570 * layer destruct the object for us
1573 void tty_kref_put(struct tty_struct *tty)
1576 kref_put(&tty->kref, queue_release_one_tty);
1578 EXPORT_SYMBOL(tty_kref_put);
1581 * release_tty - release tty structure memory
1583 * Release both @tty and a possible linked partner (think pty pair),
1584 * and decrement the refcount of the backing module.
1588 * takes the file list lock internally when working on the list
1589 * of ttys that the driver keeps.
1592 static void release_tty(struct tty_struct *tty, int idx)
1594 /* This should always be true but check for the moment */
1595 WARN_ON(tty->index != idx);
1596 WARN_ON(!mutex_is_locked(&tty_mutex));
1597 if (tty->ops->shutdown)
1598 tty->ops->shutdown(tty);
1599 tty_save_termios(tty);
1600 tty_driver_remove_tty(tty->driver, tty);
1602 tty->port->itty = NULL;
1604 tty->link->port->itty = NULL;
1606 tty_buffer_cancel_work(tty->port);
1608 tty_buffer_cancel_work(tty->link->port);
1610 tty_kref_put(tty->link);
1615 * tty_release_checks - check a tty before real release
1616 * @tty: tty to check
1617 * @idx: index of the tty
1619 * Performs some paranoid checking before true release of the @tty.
1620 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1622 static int tty_release_checks(struct tty_struct *tty, int idx)
1624 #ifdef TTY_PARANOIA_CHECK
1625 if (idx < 0 || idx >= tty->driver->num) {
1626 tty_debug(tty, "bad idx %d\n", idx);
1630 /* not much to check for devpts */
1631 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1634 if (tty != tty->driver->ttys[idx]) {
1635 tty_debug(tty, "bad driver table[%d] = %p\n",
1636 idx, tty->driver->ttys[idx]);
1639 if (tty->driver->other) {
1640 struct tty_struct *o_tty = tty->link;
1642 if (o_tty != tty->driver->other->ttys[idx]) {
1643 tty_debug(tty, "bad other table[%d] = %p\n",
1644 idx, tty->driver->other->ttys[idx]);
1647 if (o_tty->link != tty) {
1648 tty_debug(tty, "bad link = %p\n", o_tty->link);
1657 * tty_kclose - closes tty opened by tty_kopen
1660 * Performs the final steps to release and free a tty device. It is the
1661 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1662 * flag on tty->port.
1664 void tty_kclose(struct tty_struct *tty)
1667 * Ask the line discipline code to release its structures
1669 tty_ldisc_release(tty);
1671 /* Wait for pending work before tty destruction commmences */
1672 tty_flush_works(tty);
1674 tty_debug_hangup(tty, "freeing structure\n");
1676 * The release_tty function takes care of the details of clearing
1677 * the slots and preserving the termios structure.
1679 mutex_lock(&tty_mutex);
1680 tty_port_set_kopened(tty->port, 0);
1681 release_tty(tty, tty->index);
1682 mutex_unlock(&tty_mutex);
1684 EXPORT_SYMBOL_GPL(tty_kclose);
1687 * tty_release_struct - release a tty struct
1689 * @idx: index of the tty
1691 * Performs the final steps to release and free a tty device. It is
1692 * roughly the reverse of tty_init_dev.
1694 void tty_release_struct(struct tty_struct *tty, int idx)
1697 * Ask the line discipline code to release its structures
1699 tty_ldisc_release(tty);
1701 /* Wait for pending work before tty destruction commmences */
1702 tty_flush_works(tty);
1704 tty_debug_hangup(tty, "freeing structure\n");
1706 * The release_tty function takes care of the details of clearing
1707 * the slots and preserving the termios structure.
1709 mutex_lock(&tty_mutex);
1710 release_tty(tty, idx);
1711 mutex_unlock(&tty_mutex);
1713 EXPORT_SYMBOL_GPL(tty_release_struct);
1716 * tty_release - vfs callback for close
1717 * @inode: inode of tty
1718 * @filp: file pointer for handle to tty
1720 * Called the last time each file handle is closed that references
1721 * this tty. There may however be several such references.
1724 * Takes bkl. See tty_release_dev
1726 * Even releasing the tty structures is a tricky business.. We have
1727 * to be very careful that the structures are all released at the
1728 * same time, as interrupts might otherwise get the wrong pointers.
1730 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1731 * lead to double frees or releasing memory still in use.
1734 int tty_release(struct inode *inode, struct file *filp)
1736 struct tty_struct *tty = file_tty(filp);
1737 struct tty_struct *o_tty = NULL;
1738 int do_sleep, final;
1743 if (tty_paranoia_check(tty, inode, __func__))
1747 check_tty_count(tty, __func__);
1749 __tty_fasync(-1, filp, 0);
1752 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1753 tty->driver->subtype == PTY_TYPE_MASTER)
1756 if (tty_release_checks(tty, idx)) {
1761 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1763 if (tty->ops->close)
1764 tty->ops->close(tty, filp);
1766 /* If tty is pty master, lock the slave pty (stable lock order) */
1767 tty_lock_slave(o_tty);
1770 * Sanity check: if tty->count is going to zero, there shouldn't be
1771 * any waiters on tty->read_wait or tty->write_wait. We test the
1772 * wait queues and kick everyone out _before_ actually starting to
1773 * close. This ensures that we won't block while releasing the tty
1776 * The test for the o_tty closing is necessary, since the master and
1777 * slave sides may close in any order. If the slave side closes out
1778 * first, its count will be one, since the master side holds an open.
1779 * Thus this test wouldn't be triggered at the time the slave closed,
1785 if (tty->count <= 1) {
1786 if (waitqueue_active(&tty->read_wait)) {
1787 wake_up_poll(&tty->read_wait, EPOLLIN);
1790 if (waitqueue_active(&tty->write_wait)) {
1791 wake_up_poll(&tty->write_wait, EPOLLOUT);
1795 if (o_tty && o_tty->count <= 1) {
1796 if (waitqueue_active(&o_tty->read_wait)) {
1797 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1800 if (waitqueue_active(&o_tty->write_wait)) {
1801 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1810 tty_warn(tty, "read/write wait queue active!\n");
1812 schedule_timeout_killable(timeout);
1813 if (timeout < 120 * HZ)
1814 timeout = 2 * timeout + 1;
1816 timeout = MAX_SCHEDULE_TIMEOUT;
1820 if (--o_tty->count < 0) {
1821 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1825 if (--tty->count < 0) {
1826 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1831 * We've decremented tty->count, so we need to remove this file
1832 * descriptor off the tty->tty_files list; this serves two
1834 * - check_tty_count sees the correct number of file descriptors
1835 * associated with this tty.
1836 * - do_tty_hangup no longer sees this file descriptor as
1837 * something that needs to be handled for hangups.
1842 * Perform some housekeeping before deciding whether to return.
1844 * If _either_ side is closing, make sure there aren't any
1845 * processes that still think tty or o_tty is their controlling
1849 read_lock(&tasklist_lock);
1850 session_clear_tty(tty->session);
1852 session_clear_tty(o_tty->session);
1853 read_unlock(&tasklist_lock);
1856 /* check whether both sides are closing ... */
1857 final = !tty->count && !(o_tty && o_tty->count);
1859 tty_unlock_slave(o_tty);
1862 /* At this point, the tty->count == 0 should ensure a dead tty
1863 cannot be re-opened by a racing opener */
1868 tty_debug_hangup(tty, "final close\n");
1870 tty_release_struct(tty, idx);
1875 * tty_open_current_tty - get locked tty of current task
1876 * @device: device number
1877 * @filp: file pointer to tty
1878 * @return: locked tty of the current task iff @device is /dev/tty
1880 * Performs a re-open of the current task's controlling tty.
1882 * We cannot return driver and index like for the other nodes because
1883 * devpts will not work then. It expects inodes to be from devpts FS.
1885 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1887 struct tty_struct *tty;
1890 if (device != MKDEV(TTYAUX_MAJOR, 0))
1893 tty = get_current_tty();
1895 return ERR_PTR(-ENXIO);
1897 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1900 tty_kref_put(tty); /* safe to drop the kref now */
1902 retval = tty_reopen(tty);
1905 tty = ERR_PTR(retval);
1911 * tty_lookup_driver - lookup a tty driver for a given device file
1912 * @device: device number
1913 * @filp: file pointer to tty
1914 * @index: index for the device in the @return driver
1915 * @return: driver for this inode (with increased refcount)
1917 * If @return is not erroneous, the caller is responsible to decrement the
1918 * refcount by tty_driver_kref_put.
1920 * Locking: tty_mutex protects get_tty_driver
1922 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1925 struct tty_driver *driver = NULL;
1929 case MKDEV(TTY_MAJOR, 0): {
1930 extern struct tty_driver *console_driver;
1931 driver = tty_driver_kref_get(console_driver);
1932 *index = fg_console;
1936 case MKDEV(TTYAUX_MAJOR, 1): {
1937 struct tty_driver *console_driver = console_device(index);
1938 if (console_driver) {
1939 driver = tty_driver_kref_get(console_driver);
1940 if (driver && filp) {
1941 /* Don't let /dev/console block */
1942 filp->f_flags |= O_NONBLOCK;
1947 tty_driver_kref_put(driver);
1948 return ERR_PTR(-ENODEV);
1951 driver = get_tty_driver(device, index);
1953 return ERR_PTR(-ENODEV);
1960 * tty_kopen - open a tty device for kernel
1961 * @device: dev_t of device to open
1963 * Opens tty exclusively for kernel. Performs the driver lookup,
1964 * makes sure it's not already opened and performs the first-time
1965 * tty initialization.
1967 * Returns the locked initialized &tty_struct
1969 * Claims the global tty_mutex to serialize:
1970 * - concurrent first-time tty initialization
1971 * - concurrent tty driver removal w/ lookup
1972 * - concurrent tty removal from driver table
1974 struct tty_struct *tty_kopen(dev_t device)
1976 struct tty_struct *tty;
1977 struct tty_driver *driver;
1980 mutex_lock(&tty_mutex);
1981 driver = tty_lookup_driver(device, NULL, &index);
1982 if (IS_ERR(driver)) {
1983 mutex_unlock(&tty_mutex);
1984 return ERR_CAST(driver);
1987 /* check whether we're reopening an existing tty */
1988 tty = tty_driver_lookup_tty(driver, NULL, index);
1993 /* drop kref from tty_driver_lookup_tty() */
1995 tty = ERR_PTR(-EBUSY);
1996 } else { /* tty_init_dev returns tty with the tty_lock held */
1997 tty = tty_init_dev(driver, index);
2000 tty_port_set_kopened(tty->port, 1);
2003 mutex_unlock(&tty_mutex);
2004 tty_driver_kref_put(driver);
2007 EXPORT_SYMBOL_GPL(tty_kopen);
2010 * tty_open_by_driver - open a tty device
2011 * @device: dev_t of device to open
2012 * @filp: file pointer to tty
2014 * Performs the driver lookup, checks for a reopen, or otherwise
2015 * performs the first-time tty initialization.
2017 * Returns the locked initialized or re-opened &tty_struct
2019 * Claims the global tty_mutex to serialize:
2020 * - concurrent first-time tty initialization
2021 * - concurrent tty driver removal w/ lookup
2022 * - concurrent tty removal from driver table
2024 static struct tty_struct *tty_open_by_driver(dev_t device,
2027 struct tty_struct *tty;
2028 struct tty_driver *driver = NULL;
2032 mutex_lock(&tty_mutex);
2033 driver = tty_lookup_driver(device, filp, &index);
2034 if (IS_ERR(driver)) {
2035 mutex_unlock(&tty_mutex);
2036 return ERR_CAST(driver);
2039 /* check whether we're reopening an existing tty */
2040 tty = tty_driver_lookup_tty(driver, filp, index);
2042 mutex_unlock(&tty_mutex);
2047 if (tty_port_kopened(tty->port)) {
2049 mutex_unlock(&tty_mutex);
2050 tty = ERR_PTR(-EBUSY);
2053 mutex_unlock(&tty_mutex);
2054 retval = tty_lock_interruptible(tty);
2055 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2057 if (retval == -EINTR)
2058 retval = -ERESTARTSYS;
2059 tty = ERR_PTR(retval);
2062 retval = tty_reopen(tty);
2065 tty = ERR_PTR(retval);
2067 } else { /* Returns with the tty_lock held for now */
2068 tty = tty_init_dev(driver, index);
2069 mutex_unlock(&tty_mutex);
2072 tty_driver_kref_put(driver);
2077 * tty_open - open a tty device
2078 * @inode: inode of device file
2079 * @filp: file pointer to tty
2081 * tty_open and tty_release keep up the tty count that contains the
2082 * number of opens done on a tty. We cannot use the inode-count, as
2083 * different inodes might point to the same tty.
2085 * Open-counting is needed for pty masters, as well as for keeping
2086 * track of serial lines: DTR is dropped when the last close happens.
2087 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2089 * The termios state of a pty is reset on first open so that
2090 * settings don't persist across reuse.
2092 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2093 * tty->count should protect the rest.
2094 * ->siglock protects ->signal/->sighand
2096 * Note: the tty_unlock/lock cases without a ref are only safe due to
2100 static int tty_open(struct inode *inode, struct file *filp)
2102 struct tty_struct *tty;
2104 dev_t device = inode->i_rdev;
2105 unsigned saved_flags = filp->f_flags;
2107 nonseekable_open(inode, filp);
2110 retval = tty_alloc_file(filp);
2114 tty = tty_open_current_tty(device, filp);
2116 tty = tty_open_by_driver(device, filp);
2119 tty_free_file(filp);
2120 retval = PTR_ERR(tty);
2121 if (retval != -EAGAIN || signal_pending(current))
2127 tty_add_file(tty, filp);
2129 check_tty_count(tty, __func__);
2130 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2133 retval = tty->ops->open(tty, filp);
2136 filp->f_flags = saved_flags;
2139 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2141 tty_unlock(tty); /* need to call tty_release without BTM */
2142 tty_release(inode, filp);
2143 if (retval != -ERESTARTSYS)
2146 if (signal_pending(current))
2151 * Need to reset f_op in case a hangup happened.
2153 if (tty_hung_up_p(filp))
2154 filp->f_op = &tty_fops;
2157 clear_bit(TTY_HUPPED, &tty->flags);
2159 noctty = (filp->f_flags & O_NOCTTY) ||
2160 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2161 device == MKDEV(TTYAUX_MAJOR, 1) ||
2162 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2163 tty->driver->subtype == PTY_TYPE_MASTER);
2165 tty_open_proc_set_tty(filp, tty);
2173 * tty_poll - check tty status
2174 * @filp: file being polled
2175 * @wait: poll wait structures to update
2177 * Call the line discipline polling method to obtain the poll
2178 * status of the device.
2180 * Locking: locks called line discipline but ldisc poll method
2181 * may be re-entered freely by other callers.
2184 static __poll_t tty_poll(struct file *filp, poll_table *wait)
2186 struct tty_struct *tty = file_tty(filp);
2187 struct tty_ldisc *ld;
2190 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2193 ld = tty_ldisc_ref_wait(tty);
2195 return hung_up_tty_poll(filp, wait);
2197 ret = ld->ops->poll(tty, filp, wait);
2198 tty_ldisc_deref(ld);
2202 static int __tty_fasync(int fd, struct file *filp, int on)
2204 struct tty_struct *tty = file_tty(filp);
2205 unsigned long flags;
2208 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2211 retval = fasync_helper(fd, filp, on, &tty->fasync);
2219 spin_lock_irqsave(&tty->ctrl_lock, flags);
2222 type = PIDTYPE_PGID;
2224 pid = task_pid(current);
2225 type = PIDTYPE_TGID;
2228 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2229 __f_setown(filp, pid, type, 0);
2237 static int tty_fasync(int fd, struct file *filp, int on)
2239 struct tty_struct *tty = file_tty(filp);
2240 int retval = -ENOTTY;
2243 if (!tty_hung_up_p(filp))
2244 retval = __tty_fasync(fd, filp, on);
2251 * tiocsti - fake input character
2252 * @tty: tty to fake input into
2253 * @p: pointer to character
2255 * Fake input to a tty device. Does the necessary locking and
2258 * FIXME: does not honour flow control ??
2261 * Called functions take tty_ldiscs_lock
2262 * current->signal->tty check is safe without locks
2265 static int tiocsti(struct tty_struct *tty, char __user *p)
2268 struct tty_ldisc *ld;
2270 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2272 if (get_user(ch, p))
2274 tty_audit_tiocsti(tty, ch);
2275 ld = tty_ldisc_ref_wait(tty);
2278 tty_buffer_lock_exclusive(tty->port);
2279 if (ld->ops->receive_buf)
2280 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2281 tty_buffer_unlock_exclusive(tty->port);
2282 tty_ldisc_deref(ld);
2287 * tiocgwinsz - implement window query ioctl
2289 * @arg: user buffer for result
2291 * Copies the kernel idea of the window size into the user buffer.
2293 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2297 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2301 mutex_lock(&tty->winsize_mutex);
2302 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2303 mutex_unlock(&tty->winsize_mutex);
2305 return err ? -EFAULT: 0;
2309 * tty_do_resize - resize event
2310 * @tty: tty being resized
2311 * @ws: new dimensions
2313 * Update the termios variables and send the necessary signals to
2314 * peform a terminal resize correctly
2317 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2322 mutex_lock(&tty->winsize_mutex);
2323 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2326 /* Signal the foreground process group */
2327 pgrp = tty_get_pgrp(tty);
2329 kill_pgrp(pgrp, SIGWINCH, 1);
2334 mutex_unlock(&tty->winsize_mutex);
2337 EXPORT_SYMBOL(tty_do_resize);
2340 * tiocswinsz - implement window size set ioctl
2341 * @tty: tty side of tty
2342 * @arg: user buffer for result
2344 * Copies the user idea of the window size to the kernel. Traditionally
2345 * this is just advisory information but for the Linux console it
2346 * actually has driver level meaning and triggers a VC resize.
2349 * Driver dependent. The default do_resize method takes the
2350 * tty termios mutex and ctrl_lock. The console takes its own lock
2351 * then calls into the default method.
2354 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2356 struct winsize tmp_ws;
2357 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2360 if (tty->ops->resize)
2361 return tty->ops->resize(tty, &tmp_ws);
2363 return tty_do_resize(tty, &tmp_ws);
2367 * tioccons - allow admin to move logical console
2368 * @file: the file to become console
2370 * Allow the administrator to move the redirected console device
2372 * Locking: uses redirect_lock to guard the redirect information
2375 static int tioccons(struct file *file)
2377 if (!capable(CAP_SYS_ADMIN))
2379 if (file->f_op->write_iter == redirected_tty_write) {
2381 spin_lock(&redirect_lock);
2384 spin_unlock(&redirect_lock);
2389 if (file->f_op->write_iter != tty_write)
2391 if (!(file->f_mode & FMODE_WRITE))
2393 if (!(file->f_mode & FMODE_CAN_WRITE))
2395 spin_lock(&redirect_lock);
2397 spin_unlock(&redirect_lock);
2400 redirect = get_file(file);
2401 spin_unlock(&redirect_lock);
2406 * tiocsetd - set line discipline
2408 * @p: pointer to user data
2410 * Set the line discipline according to user request.
2412 * Locking: see tty_set_ldisc, this function is just a helper
2415 static int tiocsetd(struct tty_struct *tty, int __user *p)
2420 if (get_user(disc, p))
2423 ret = tty_set_ldisc(tty, disc);
2429 * tiocgetd - get line discipline
2431 * @p: pointer to user data
2433 * Retrieves the line discipline id directly from the ldisc.
2435 * Locking: waits for ldisc reference (in case the line discipline
2436 * is changing or the tty is being hungup)
2439 static int tiocgetd(struct tty_struct *tty, int __user *p)
2441 struct tty_ldisc *ld;
2444 ld = tty_ldisc_ref_wait(tty);
2447 ret = put_user(ld->ops->num, p);
2448 tty_ldisc_deref(ld);
2453 * send_break - performed time break
2454 * @tty: device to break on
2455 * @duration: timeout in mS
2457 * Perform a timed break on hardware that lacks its own driver level
2458 * timed break functionality.
2461 * atomic_write_lock serializes
2465 static int send_break(struct tty_struct *tty, unsigned int duration)
2469 if (tty->ops->break_ctl == NULL)
2472 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2473 return tty->ops->break_ctl(tty, duration);
2475 /* Do the work ourselves */
2476 if (tty_write_lock(tty, false) < 0)
2479 retval = tty->ops->break_ctl(tty, -1);
2481 msleep_interruptible(duration);
2482 retval = tty->ops->break_ctl(tty, 0);
2483 } else if (retval == -EOPNOTSUPP) {
2484 /* some drivers can tell only dynamically */
2487 tty_write_unlock(tty);
2489 if (signal_pending(current))
2496 * tty_tiocmget - get modem status
2498 * @p: pointer to result
2500 * Obtain the modem status bits from the tty driver if the feature
2501 * is supported. Return -ENOTTY if it is not available.
2503 * Locking: none (up to the driver)
2506 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2508 int retval = -ENOTTY;
2510 if (tty->ops->tiocmget) {
2511 retval = tty->ops->tiocmget(tty);
2514 retval = put_user(retval, p);
2520 * tty_tiocmset - set modem status
2522 * @cmd: command - clear bits, set bits or set all
2523 * @p: pointer to desired bits
2525 * Set the modem status bits from the tty driver if the feature
2526 * is supported. Return -ENOTTY if it is not available.
2528 * Locking: none (up to the driver)
2531 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2535 unsigned int set, clear, val;
2537 if (tty->ops->tiocmset == NULL)
2540 retval = get_user(val, p);
2556 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2557 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2558 return tty->ops->tiocmset(tty, set, clear);
2561 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2563 int retval = -EINVAL;
2564 struct serial_icounter_struct icount;
2565 memset(&icount, 0, sizeof(icount));
2566 if (tty->ops->get_icount)
2567 retval = tty->ops->get_icount(tty, &icount);
2570 if (copy_to_user(arg, &icount, sizeof(icount)))
2575 static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
2577 static DEFINE_RATELIMIT_STATE(depr_flags,
2578 DEFAULT_RATELIMIT_INTERVAL,
2579 DEFAULT_RATELIMIT_BURST);
2580 char comm[TASK_COMM_LEN];
2581 struct serial_struct v;
2584 if (copy_from_user(&v, ss, sizeof(*ss)))
2587 flags = v.flags & ASYNC_DEPRECATED;
2589 if (flags && __ratelimit(&depr_flags))
2590 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2591 __func__, get_task_comm(comm, current), flags);
2592 if (!tty->ops->set_serial)
2594 return tty->ops->set_serial(tty, &v);
2597 static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
2599 struct serial_struct v;
2602 memset(&v, 0, sizeof(v));
2603 if (!tty->ops->get_serial)
2605 err = tty->ops->get_serial(tty, &v);
2606 if (!err && copy_to_user(ss, &v, sizeof(v)))
2612 * if pty, return the slave side (real_tty)
2613 * otherwise, return self
2615 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2617 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2618 tty->driver->subtype == PTY_TYPE_MASTER)
2624 * Split this up, as gcc can choke on it otherwise..
2626 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2628 struct tty_struct *tty = file_tty(file);
2629 struct tty_struct *real_tty;
2630 void __user *p = (void __user *)arg;
2632 struct tty_ldisc *ld;
2634 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2637 real_tty = tty_pair_get_tty(tty);
2640 * Factor out some common prep work
2648 retval = tty_check_change(tty);
2651 if (cmd != TIOCCBRK) {
2652 tty_wait_until_sent(tty, 0);
2653 if (signal_pending(current))
2664 return tiocsti(tty, p);
2666 return tiocgwinsz(real_tty, p);
2668 return tiocswinsz(real_tty, p);
2670 return real_tty != tty ? -EINVAL : tioccons(file);
2672 set_bit(TTY_EXCLUSIVE, &tty->flags);
2675 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2679 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2680 return put_user(excl, (int __user *)p);
2683 return tiocgetd(tty, p);
2685 return tiocsetd(tty, p);
2687 if (!capable(CAP_SYS_ADMIN))
2693 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2694 return put_user(ret, (unsigned int __user *)p);
2699 case TIOCSBRK: /* Turn break on, unconditionally */
2700 if (tty->ops->break_ctl)
2701 return tty->ops->break_ctl(tty, -1);
2703 case TIOCCBRK: /* Turn break off, unconditionally */
2704 if (tty->ops->break_ctl)
2705 return tty->ops->break_ctl(tty, 0);
2707 case TCSBRK: /* SVID version: non-zero arg --> no break */
2708 /* non-zero arg means wait for all output data
2709 * to be sent (performed above) but don't send break.
2710 * This is used by the tcdrain() termios function.
2713 return send_break(tty, 250);
2715 case TCSBRKP: /* support for POSIX tcsendbreak() */
2716 return send_break(tty, arg ? arg*100 : 250);
2719 return tty_tiocmget(tty, p);
2723 return tty_tiocmset(tty, cmd, p);
2725 return tty_tiocgicount(tty, p);
2730 /* flush tty buffer and allow ldisc to process ioctl */
2731 tty_buffer_flush(tty, NULL);
2736 return tty_tiocsserial(tty, p);
2738 return tty_tiocgserial(tty, p);
2740 /* Special because the struct file is needed */
2741 return ptm_open_peer(file, tty, (int)arg);
2743 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2744 if (retval != -ENOIOCTLCMD)
2747 if (tty->ops->ioctl) {
2748 retval = tty->ops->ioctl(tty, cmd, arg);
2749 if (retval != -ENOIOCTLCMD)
2752 ld = tty_ldisc_ref_wait(tty);
2754 return hung_up_tty_ioctl(file, cmd, arg);
2756 if (ld->ops->ioctl) {
2757 retval = ld->ops->ioctl(tty, file, cmd, arg);
2758 if (retval == -ENOIOCTLCMD)
2761 tty_ldisc_deref(ld);
2765 #ifdef CONFIG_COMPAT
2767 struct serial_struct32 {
2773 compat_int_t xmit_fifo_size;
2774 compat_int_t custom_divisor;
2775 compat_int_t baud_base;
2776 unsigned short close_delay;
2780 unsigned short closing_wait; /* time to wait before closing */
2781 unsigned short closing_wait2; /* no longer used... */
2782 compat_uint_t iomem_base;
2783 unsigned short iomem_reg_shift;
2784 unsigned int port_high;
2785 /* compat_ulong_t iomap_base FIXME */
2786 compat_int_t reserved;
2789 static int compat_tty_tiocsserial(struct tty_struct *tty,
2790 struct serial_struct32 __user *ss)
2792 static DEFINE_RATELIMIT_STATE(depr_flags,
2793 DEFAULT_RATELIMIT_INTERVAL,
2794 DEFAULT_RATELIMIT_BURST);
2795 char comm[TASK_COMM_LEN];
2796 struct serial_struct32 v32;
2797 struct serial_struct v;
2800 if (copy_from_user(&v32, ss, sizeof(*ss)))
2803 memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base));
2804 v.iomem_base = compat_ptr(v32.iomem_base);
2805 v.iomem_reg_shift = v32.iomem_reg_shift;
2806 v.port_high = v32.port_high;
2809 flags = v.flags & ASYNC_DEPRECATED;
2811 if (flags && __ratelimit(&depr_flags))
2812 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2813 __func__, get_task_comm(comm, current), flags);
2814 if (!tty->ops->set_serial)
2816 return tty->ops->set_serial(tty, &v);
2819 static int compat_tty_tiocgserial(struct tty_struct *tty,
2820 struct serial_struct32 __user *ss)
2822 struct serial_struct32 v32;
2823 struct serial_struct v;
2826 memset(&v, 0, sizeof(v));
2827 memset(&v32, 0, sizeof(v32));
2829 if (!tty->ops->get_serial)
2831 err = tty->ops->get_serial(tty, &v);
2833 memcpy(&v32, &v, offsetof(struct serial_struct32, iomem_base));
2834 v32.iomem_base = (unsigned long)v.iomem_base >> 32 ?
2835 0xfffffff : ptr_to_compat(v.iomem_base);
2836 v32.iomem_reg_shift = v.iomem_reg_shift;
2837 v32.port_high = v.port_high;
2838 if (copy_to_user(ss, &v32, sizeof(v32)))
2843 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2846 struct tty_struct *tty = file_tty(file);
2847 struct tty_ldisc *ld;
2848 int retval = -ENOIOCTLCMD;
2897 case TIOCGLCKTRMIOS:
2898 case TIOCSLCKTRMIOS:
2910 return tty_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2926 return tty_ioctl(file, cmd, arg);
2929 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2934 return compat_tty_tiocsserial(tty, compat_ptr(arg));
2936 return compat_tty_tiocgserial(tty, compat_ptr(arg));
2938 if (tty->ops->compat_ioctl) {
2939 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2940 if (retval != -ENOIOCTLCMD)
2944 ld = tty_ldisc_ref_wait(tty);
2946 return hung_up_tty_compat_ioctl(file, cmd, arg);
2947 if (ld->ops->compat_ioctl)
2948 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2949 if (retval == -ENOIOCTLCMD && ld->ops->ioctl)
2950 retval = ld->ops->ioctl(tty, file,
2951 (unsigned long)compat_ptr(cmd), arg);
2952 tty_ldisc_deref(ld);
2958 static int this_tty(const void *t, struct file *file, unsigned fd)
2960 if (likely(file->f_op->read_iter != tty_read))
2962 return file_tty(file) != t ? 0 : fd + 1;
2966 * This implements the "Secure Attention Key" --- the idea is to
2967 * prevent trojan horses by killing all processes associated with this
2968 * tty when the user hits the "Secure Attention Key". Required for
2969 * super-paranoid applications --- see the Orange Book for more details.
2971 * This code could be nicer; ideally it should send a HUP, wait a few
2972 * seconds, then send a INT, and then a KILL signal. But you then
2973 * have to coordinate with the init process, since all processes associated
2974 * with the current tty must be dead before the new getty is allowed
2977 * Now, if it would be correct ;-/ The current code has a nasty hole -
2978 * it doesn't catch files in flight. We may send the descriptor to ourselves
2979 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2981 * Nasty bug: do_SAK is being called in interrupt context. This can
2982 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2984 void __do_SAK(struct tty_struct *tty)
2989 struct task_struct *g, *p;
2990 struct pid *session;
2992 unsigned long flags;
2997 spin_lock_irqsave(&tty->ctrl_lock, flags);
2998 session = get_pid(tty->session);
2999 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3001 tty_ldisc_flush(tty);
3003 tty_driver_flush_buffer(tty);
3005 read_lock(&tasklist_lock);
3006 /* Kill the entire session */
3007 do_each_pid_task(session, PIDTYPE_SID, p) {
3008 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3009 task_pid_nr(p), p->comm);
3010 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
3011 } while_each_pid_task(session, PIDTYPE_SID, p);
3013 /* Now kill any processes that happen to have the tty open */
3014 do_each_thread(g, p) {
3015 if (p->signal->tty == tty) {
3016 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3017 task_pid_nr(p), p->comm);
3018 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
3022 i = iterate_fd(p->files, 0, this_tty, tty);
3024 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3025 task_pid_nr(p), p->comm, i - 1);
3026 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
3029 } while_each_thread(g, p);
3030 read_unlock(&tasklist_lock);
3035 static void do_SAK_work(struct work_struct *work)
3037 struct tty_struct *tty =
3038 container_of(work, struct tty_struct, SAK_work);
3043 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3044 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3045 * the values which we write to it will be identical to the values which it
3046 * already has. --akpm
3048 void do_SAK(struct tty_struct *tty)
3052 schedule_work(&tty->SAK_work);
3055 EXPORT_SYMBOL(do_SAK);
3057 /* Must put_device() after it's unused! */
3058 static struct device *tty_get_device(struct tty_struct *tty)
3060 dev_t devt = tty_devnum(tty);
3061 return class_find_device_by_devt(tty_class, devt);
3068 * This subroutine allocates and initializes a tty structure.
3070 * Locking: none - tty in question is not exposed at this point
3073 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3075 struct tty_struct *tty;
3077 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3081 kref_init(&tty->kref);
3082 tty->magic = TTY_MAGIC;
3083 if (tty_ldisc_init(tty)) {
3087 tty->session = NULL;
3089 mutex_init(&tty->legacy_mutex);
3090 mutex_init(&tty->throttle_mutex);
3091 init_rwsem(&tty->termios_rwsem);
3092 mutex_init(&tty->winsize_mutex);
3093 init_ldsem(&tty->ldisc_sem);
3094 init_waitqueue_head(&tty->write_wait);
3095 init_waitqueue_head(&tty->read_wait);
3096 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3097 mutex_init(&tty->atomic_write_lock);
3098 spin_lock_init(&tty->ctrl_lock);
3099 spin_lock_init(&tty->flow_lock);
3100 spin_lock_init(&tty->files_lock);
3101 INIT_LIST_HEAD(&tty->tty_files);
3102 INIT_WORK(&tty->SAK_work, do_SAK_work);
3104 tty->driver = driver;
3105 tty->ops = driver->ops;
3107 tty_line_name(driver, idx, tty->name);
3108 tty->dev = tty_get_device(tty);
3114 * tty_put_char - write one character to a tty
3118 * Write one byte to the tty using the provided put_char method
3119 * if present. Returns the number of characters successfully output.
3121 * Note: the specific put_char operation in the driver layer may go
3122 * away soon. Don't call it directly, use this method
3125 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3127 if (tty->ops->put_char)
3128 return tty->ops->put_char(tty, ch);
3129 return tty->ops->write(tty, &ch, 1);
3131 EXPORT_SYMBOL_GPL(tty_put_char);
3133 struct class *tty_class;
3135 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3136 unsigned int index, unsigned int count)
3140 /* init here, since reused cdevs cause crashes */
3141 driver->cdevs[index] = cdev_alloc();
3142 if (!driver->cdevs[index])
3144 driver->cdevs[index]->ops = &tty_fops;
3145 driver->cdevs[index]->owner = driver->owner;
3146 err = cdev_add(driver->cdevs[index], dev, count);
3148 kobject_put(&driver->cdevs[index]->kobj);
3153 * tty_register_device - register a tty device
3154 * @driver: the tty driver that describes the tty device
3155 * @index: the index in the tty driver for this tty device
3156 * @device: a struct device that is associated with this tty device.
3157 * This field is optional, if there is no known struct device
3158 * for this tty device it can be set to NULL safely.
3160 * Returns a pointer to the struct device for this tty device
3161 * (or ERR_PTR(-EFOO) on error).
3163 * This call is required to be made to register an individual tty device
3164 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3165 * that bit is not set, this function should not be called by a tty
3171 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3172 struct device *device)
3174 return tty_register_device_attr(driver, index, device, NULL, NULL);
3176 EXPORT_SYMBOL(tty_register_device);
3178 static void tty_device_create_release(struct device *dev)
3180 dev_dbg(dev, "releasing...\n");
3185 * tty_register_device_attr - register a tty device
3186 * @driver: the tty driver that describes the tty device
3187 * @index: the index in the tty driver for this tty device
3188 * @device: a struct device that is associated with this tty device.
3189 * This field is optional, if there is no known struct device
3190 * for this tty device it can be set to NULL safely.
3191 * @drvdata: Driver data to be set to device.
3192 * @attr_grp: Attribute group to be set on device.
3194 * Returns a pointer to the struct device for this tty device
3195 * (or ERR_PTR(-EFOO) on error).
3197 * This call is required to be made to register an individual tty device
3198 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3199 * that bit is not set, this function should not be called by a tty
3204 struct device *tty_register_device_attr(struct tty_driver *driver,
3205 unsigned index, struct device *device,
3207 const struct attribute_group **attr_grp)
3210 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3211 struct ktermios *tp;
3215 if (index >= driver->num) {
3216 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3217 driver->name, index);
3218 return ERR_PTR(-EINVAL);
3221 if (driver->type == TTY_DRIVER_TYPE_PTY)
3222 pty_line_name(driver, index, name);
3224 tty_line_name(driver, index, name);
3226 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3228 return ERR_PTR(-ENOMEM);
3231 dev->class = tty_class;
3232 dev->parent = device;
3233 dev->release = tty_device_create_release;
3234 dev_set_name(dev, "%s", name);
3235 dev->groups = attr_grp;
3236 dev_set_drvdata(dev, drvdata);
3238 dev_set_uevent_suppress(dev, 1);
3240 retval = device_register(dev);
3244 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3246 * Free any saved termios data so that the termios state is
3247 * reset when reusing a minor number.
3249 tp = driver->termios[index];
3251 driver->termios[index] = NULL;
3255 retval = tty_cdev_add(driver, devt, index, 1);
3260 dev_set_uevent_suppress(dev, 0);
3261 kobject_uevent(&dev->kobj, KOBJ_ADD);
3270 return ERR_PTR(retval);
3272 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3275 * tty_unregister_device - unregister a tty device
3276 * @driver: the tty driver that describes the tty device
3277 * @index: the index in the tty driver for this tty device
3279 * If a tty device is registered with a call to tty_register_device() then
3280 * this function must be called when the tty device is gone.
3285 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3287 device_destroy(tty_class,
3288 MKDEV(driver->major, driver->minor_start) + index);
3289 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3290 cdev_del(driver->cdevs[index]);
3291 driver->cdevs[index] = NULL;
3294 EXPORT_SYMBOL(tty_unregister_device);
3297 * __tty_alloc_driver -- allocate tty driver
3298 * @lines: count of lines this driver can handle at most
3299 * @owner: module which is responsible for this driver
3300 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3302 * This should not be called directly, some of the provided macros should be
3303 * used instead. Use IS_ERR and friends on @retval.
3305 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3306 unsigned long flags)
3308 struct tty_driver *driver;
3309 unsigned int cdevs = 1;
3312 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3313 return ERR_PTR(-EINVAL);
3315 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
3317 return ERR_PTR(-ENOMEM);
3319 kref_init(&driver->kref);
3320 driver->magic = TTY_DRIVER_MAGIC;
3321 driver->num = lines;
3322 driver->owner = owner;
3323 driver->flags = flags;
3325 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3326 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3328 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3330 if (!driver->ttys || !driver->termios) {
3336 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3337 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3339 if (!driver->ports) {
3346 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3347 if (!driver->cdevs) {
3354 kfree(driver->ports);
3355 kfree(driver->ttys);
3356 kfree(driver->termios);
3357 kfree(driver->cdevs);
3359 return ERR_PTR(err);
3361 EXPORT_SYMBOL(__tty_alloc_driver);
3363 static void destruct_tty_driver(struct kref *kref)
3365 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3367 struct ktermios *tp;
3369 if (driver->flags & TTY_DRIVER_INSTALLED) {
3370 for (i = 0; i < driver->num; i++) {
3371 tp = driver->termios[i];
3373 driver->termios[i] = NULL;
3376 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3377 tty_unregister_device(driver, i);
3379 proc_tty_unregister_driver(driver);
3380 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3381 cdev_del(driver->cdevs[0]);
3383 kfree(driver->cdevs);
3384 kfree(driver->ports);
3385 kfree(driver->termios);
3386 kfree(driver->ttys);
3390 void tty_driver_kref_put(struct tty_driver *driver)
3392 kref_put(&driver->kref, destruct_tty_driver);
3394 EXPORT_SYMBOL(tty_driver_kref_put);
3396 void tty_set_operations(struct tty_driver *driver,
3397 const struct tty_operations *op)
3401 EXPORT_SYMBOL(tty_set_operations);
3403 void put_tty_driver(struct tty_driver *d)
3405 tty_driver_kref_put(d);
3407 EXPORT_SYMBOL(put_tty_driver);
3410 * Called by a tty driver to register itself.
3412 int tty_register_driver(struct tty_driver *driver)
3419 if (!driver->major) {
3420 error = alloc_chrdev_region(&dev, driver->minor_start,
3421 driver->num, driver->name);
3423 driver->major = MAJOR(dev);
3424 driver->minor_start = MINOR(dev);
3427 dev = MKDEV(driver->major, driver->minor_start);
3428 error = register_chrdev_region(dev, driver->num, driver->name);
3433 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3434 error = tty_cdev_add(driver, dev, 0, driver->num);
3436 goto err_unreg_char;
3439 mutex_lock(&tty_mutex);
3440 list_add(&driver->tty_drivers, &tty_drivers);
3441 mutex_unlock(&tty_mutex);
3443 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3444 for (i = 0; i < driver->num; i++) {
3445 d = tty_register_device(driver, i, NULL);
3448 goto err_unreg_devs;
3452 proc_tty_register_driver(driver);
3453 driver->flags |= TTY_DRIVER_INSTALLED;
3457 for (i--; i >= 0; i--)
3458 tty_unregister_device(driver, i);
3460 mutex_lock(&tty_mutex);
3461 list_del(&driver->tty_drivers);
3462 mutex_unlock(&tty_mutex);
3465 unregister_chrdev_region(dev, driver->num);
3469 EXPORT_SYMBOL(tty_register_driver);
3472 * Called by a tty driver to unregister itself.
3474 int tty_unregister_driver(struct tty_driver *driver)
3478 if (driver->refcount)
3481 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3483 mutex_lock(&tty_mutex);
3484 list_del(&driver->tty_drivers);
3485 mutex_unlock(&tty_mutex);
3489 EXPORT_SYMBOL(tty_unregister_driver);
3491 dev_t tty_devnum(struct tty_struct *tty)
3493 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3495 EXPORT_SYMBOL(tty_devnum);
3497 void tty_default_fops(struct file_operations *fops)
3502 static char *tty_devnode(struct device *dev, umode_t *mode)
3506 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3507 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3512 static int __init tty_class_init(void)
3514 tty_class = class_create(THIS_MODULE, "tty");
3515 if (IS_ERR(tty_class))
3516 return PTR_ERR(tty_class);
3517 tty_class->devnode = tty_devnode;
3521 postcore_initcall(tty_class_init);
3523 /* 3/2004 jmc: why do these devices exist? */
3524 static struct cdev tty_cdev, console_cdev;
3526 static ssize_t show_cons_active(struct device *dev,
3527 struct device_attribute *attr, char *buf)
3529 struct console *cs[16];
3535 for_each_console(c) {
3540 if ((c->flags & CON_ENABLED) == 0)
3543 if (i >= ARRAY_SIZE(cs))
3547 int index = cs[i]->index;
3548 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3550 /* don't resolve tty0 as some programs depend on it */
3551 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3552 count += tty_line_name(drv, index, buf + count);
3554 count += sprintf(buf + count, "%s%d",
3555 cs[i]->name, cs[i]->index);
3557 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3563 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3565 static struct attribute *cons_dev_attrs[] = {
3566 &dev_attr_active.attr,
3570 ATTRIBUTE_GROUPS(cons_dev);
3572 static struct device *consdev;
3574 void console_sysfs_notify(void)
3577 sysfs_notify(&consdev->kobj, NULL, "active");
3581 * Ok, now we can initialize the rest of the tty devices and can count
3582 * on memory allocations, interrupts etc..
3584 int __init tty_init(void)
3587 cdev_init(&tty_cdev, &tty_fops);
3588 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3589 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3590 panic("Couldn't register /dev/tty driver\n");
3591 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3593 cdev_init(&console_cdev, &console_fops);
3594 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3595 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3596 panic("Couldn't register /dev/console driver\n");
3597 consdev = device_create_with_groups(tty_class, NULL,
3598 MKDEV(TTYAUX_MAJOR, 1), NULL,
3599 cons_dev_groups, "console");
3600 if (IS_ERR(consdev))
3604 vty_init(&console_fops);