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.h>
73 #include <linux/interrupt.h>
74 #include <linux/tty.h>
75 #include <linux/tty_driver.h>
76 #include <linux/tty_flip.h>
77 #include <linux/devpts_fs.h>
78 #include <linux/file.h>
79 #include <linux/fdtable.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/device.h>
92 #include <linux/wait.h>
93 #include <linux/bitops.h>
94 #include <linux/delay.h>
95 #include <linux/seq_file.h>
96 #include <linux/serial.h>
97 #include <linux/ratelimit.h>
99 #include <linux/uaccess.h>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
106 #include <linux/nsproxy.h>
108 #undef TTY_DEBUG_HANGUP
109 #ifdef TTY_DEBUG_HANGUP
110 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
112 # define tty_debug_hangup(tty, f, args...) do { } while (0)
115 #define TTY_PARANOIA_CHECK 1
116 #define CHECK_TTY_COUNT 1
118 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
119 .c_iflag = ICRNL | IXON,
120 .c_oflag = OPOST | ONLCR,
121 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
122 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
123 ECHOCTL | ECHOKE | IEXTEN,
127 /* .c_line = N_TTY, */
130 EXPORT_SYMBOL(tty_std_termios);
132 /* This list gets poked at by procfs and various bits of boot up code. This
133 could do with some rationalisation such as pulling the tty proc function
136 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
138 /* Mutex to protect creating and releasing a tty */
139 DEFINE_MUTEX(tty_mutex);
141 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
142 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
143 ssize_t redirected_tty_write(struct file *, const char __user *,
145 static unsigned int tty_poll(struct file *, poll_table *);
146 static int tty_open(struct inode *, struct file *);
147 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
149 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
152 #define tty_compat_ioctl NULL
154 static int __tty_fasync(int fd, struct file *filp, int on);
155 static int tty_fasync(int fd, struct file *filp, int on);
156 static void release_tty(struct tty_struct *tty, int idx);
159 * free_tty_struct - free a disused tty
160 * @tty: tty struct to free
162 * Free the write buffers, tty queue and tty memory itself.
164 * Locking: none. Must be called after tty is definitely unused
167 static void free_tty_struct(struct tty_struct *tty)
169 tty_ldisc_deinit(tty);
170 put_device(tty->dev);
171 kfree(tty->write_buf);
172 tty->magic = 0xDEADDEAD;
176 static inline struct tty_struct *file_tty(struct file *file)
178 return ((struct tty_file_private *)file->private_data)->tty;
181 int tty_alloc_file(struct file *file)
183 struct tty_file_private *priv;
185 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
189 file->private_data = priv;
194 /* Associate a new file with the tty structure */
195 void tty_add_file(struct tty_struct *tty, struct file *file)
197 struct tty_file_private *priv = file->private_data;
202 spin_lock(&tty->files_lock);
203 list_add(&priv->list, &tty->tty_files);
204 spin_unlock(&tty->files_lock);
208 * tty_free_file - free file->private_data
210 * This shall be used only for fail path handling when tty_add_file was not
213 void tty_free_file(struct file *file)
215 struct tty_file_private *priv = file->private_data;
217 file->private_data = NULL;
221 /* Delete file from its tty */
222 static void tty_del_file(struct file *file)
224 struct tty_file_private *priv = file->private_data;
225 struct tty_struct *tty = priv->tty;
227 spin_lock(&tty->files_lock);
228 list_del(&priv->list);
229 spin_unlock(&tty->files_lock);
234 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
237 * tty_name - return tty naming
238 * @tty: tty structure
240 * Convert a tty structure into a name. The name reflects the kernel
241 * naming policy and if udev is in use may not reflect user space
246 const char *tty_name(const struct tty_struct *tty)
248 if (!tty) /* Hmm. NULL pointer. That's fun. */
253 EXPORT_SYMBOL(tty_name);
255 const char *tty_driver_name(const struct tty_struct *tty)
257 if (!tty || !tty->driver)
259 return tty->driver->name;
262 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
265 #ifdef TTY_PARANOIA_CHECK
267 pr_warn("(%d:%d): %s: NULL tty\n",
268 imajor(inode), iminor(inode), routine);
271 if (tty->magic != TTY_MAGIC) {
272 pr_warn("(%d:%d): %s: bad magic number\n",
273 imajor(inode), iminor(inode), routine);
280 /* Caller must hold tty_lock */
281 static int check_tty_count(struct tty_struct *tty, const char *routine)
283 #ifdef CHECK_TTY_COUNT
287 spin_lock(&tty->files_lock);
288 list_for_each(p, &tty->tty_files) {
291 spin_unlock(&tty->files_lock);
292 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
293 tty->driver->subtype == PTY_TYPE_SLAVE &&
294 tty->link && tty->link->count)
296 if (tty->count != count) {
297 tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
298 routine, tty->count, 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);
330 #ifdef CONFIG_CONSOLE_POLL
333 * tty_find_polling_driver - find device of a polled tty
334 * @name: name string to match
335 * @line: pointer to resulting tty line nr
337 * This routine returns a tty driver structure, given a name
338 * and the condition that the tty driver is capable of polled
341 struct tty_driver *tty_find_polling_driver(char *name, int *line)
343 struct tty_driver *p, *res = NULL;
348 for (str = name; *str; str++)
349 if ((*str >= '0' && *str <= '9') || *str == ',')
355 tty_line = simple_strtoul(str, &str, 10);
357 mutex_lock(&tty_mutex);
358 /* Search through the tty devices to look for a match */
359 list_for_each_entry(p, &tty_drivers, tty_drivers) {
360 if (strncmp(name, p->name, len) != 0)
368 if (tty_line >= 0 && tty_line < p->num && p->ops &&
369 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
370 res = tty_driver_kref_get(p);
375 mutex_unlock(&tty_mutex);
379 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
382 static int is_ignored(int sig)
384 return (sigismember(¤t->blocked, sig) ||
385 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
389 * tty_check_change - check for POSIX terminal changes
392 * If we try to write to, or set the state of, a terminal and we're
393 * not in the foreground, send a SIGTTOU. If the signal is blocked or
394 * ignored, go ahead and perform the operation. (POSIX 7.2)
399 int __tty_check_change(struct tty_struct *tty, int sig)
402 struct pid *pgrp, *tty_pgrp;
405 if (current->signal->tty != tty)
409 pgrp = task_pgrp(current);
411 spin_lock_irqsave(&tty->ctrl_lock, flags);
412 tty_pgrp = tty->pgrp;
413 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
415 if (tty_pgrp && pgrp != tty->pgrp) {
416 if (is_ignored(sig)) {
419 } else if (is_current_pgrp_orphaned())
422 kill_pgrp(pgrp, sig, 1);
423 set_thread_flag(TIF_SIGPENDING);
430 tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);
435 int tty_check_change(struct tty_struct *tty)
437 return __tty_check_change(tty, SIGTTOU);
439 EXPORT_SYMBOL(tty_check_change);
441 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
442 size_t count, loff_t *ppos)
447 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
448 size_t count, loff_t *ppos)
453 /* No kernel lock held - none needed ;) */
454 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
456 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
459 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
462 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
465 static long hung_up_tty_compat_ioctl(struct file *file,
466 unsigned int cmd, unsigned long arg)
468 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
471 static int hung_up_tty_fasync(int fd, struct file *file, int on)
476 static const struct file_operations tty_fops = {
481 .unlocked_ioctl = tty_ioctl,
482 .compat_ioctl = tty_compat_ioctl,
484 .release = tty_release,
485 .fasync = tty_fasync,
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 void proc_clear_tty(struct task_struct *p)
518 struct tty_struct *tty;
519 spin_lock_irqsave(&p->sighand->siglock, flags);
520 tty = p->signal->tty;
521 p->signal->tty = NULL;
522 spin_unlock_irqrestore(&p->sighand->siglock, flags);
527 * proc_set_tty - set the controlling terminal
529 * Only callable by the session leader and only if it does not already have
530 * a controlling terminal.
532 * Caller must hold: tty_lock()
533 * a readlock on tasklist_lock
536 static void __proc_set_tty(struct tty_struct *tty)
540 spin_lock_irqsave(&tty->ctrl_lock, flags);
542 * The session and fg pgrp references will be non-NULL if
543 * tiocsctty() is stealing the controlling tty
545 put_pid(tty->session);
547 tty->pgrp = get_pid(task_pgrp(current));
548 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
549 tty->session = get_pid(task_session(current));
550 if (current->signal->tty) {
551 tty_debug(tty, "current tty %s not NULL!!\n",
552 current->signal->tty->name);
553 tty_kref_put(current->signal->tty);
555 put_pid(current->signal->tty_old_pgrp);
556 current->signal->tty = tty_kref_get(tty);
557 current->signal->tty_old_pgrp = NULL;
560 static void proc_set_tty(struct tty_struct *tty)
562 spin_lock_irq(¤t->sighand->siglock);
564 spin_unlock_irq(¤t->sighand->siglock);
567 struct tty_struct *get_current_tty(void)
569 struct tty_struct *tty;
572 spin_lock_irqsave(¤t->sighand->siglock, flags);
573 tty = tty_kref_get(current->signal->tty);
574 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
577 EXPORT_SYMBOL_GPL(get_current_tty);
579 static void session_clear_tty(struct pid *session)
581 struct task_struct *p;
582 do_each_pid_task(session, PIDTYPE_SID, p) {
584 } while_each_pid_task(session, PIDTYPE_SID, p);
588 * tty_wakeup - request more data
591 * Internal and external helper for wakeups of tty. This function
592 * informs the line discipline if present that the driver is ready
593 * to receive more output data.
596 void tty_wakeup(struct tty_struct *tty)
598 struct tty_ldisc *ld;
600 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
601 ld = tty_ldisc_ref(tty);
603 if (ld->ops->write_wakeup)
604 ld->ops->write_wakeup(tty);
608 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
611 EXPORT_SYMBOL_GPL(tty_wakeup);
614 * tty_signal_session_leader - sends SIGHUP to session leader
615 * @tty controlling tty
616 * @exit_session if non-zero, signal all foreground group processes
618 * Send SIGHUP and SIGCONT to the session leader and its process group.
619 * Optionally, signal all processes in the foreground process group.
621 * Returns the number of processes in the session with this tty
622 * as their controlling terminal. This value is used to drop
623 * tty references for those processes.
625 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
627 struct task_struct *p;
629 struct pid *tty_pgrp = NULL;
631 read_lock(&tasklist_lock);
633 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
634 spin_lock_irq(&p->sighand->siglock);
635 if (p->signal->tty == tty) {
636 p->signal->tty = NULL;
637 /* We defer the dereferences outside fo
641 if (!p->signal->leader) {
642 spin_unlock_irq(&p->sighand->siglock);
645 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
646 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
647 put_pid(p->signal->tty_old_pgrp); /* A noop */
648 spin_lock(&tty->ctrl_lock);
649 tty_pgrp = get_pid(tty->pgrp);
651 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
652 spin_unlock(&tty->ctrl_lock);
653 spin_unlock_irq(&p->sighand->siglock);
654 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
656 read_unlock(&tasklist_lock);
660 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
668 * __tty_hangup - actual handler for hangup events
671 * This can be called by a "kworker" kernel thread. That is process
672 * synchronous but doesn't hold any locks, so we need to make sure we
673 * have the appropriate locks for what we're doing.
675 * The hangup event clears any pending redirections onto the hung up
676 * device. It ensures future writes will error and it does the needed
677 * line discipline hangup and signal delivery. The tty object itself
682 * redirect lock for undoing redirection
683 * file list lock for manipulating list of ttys
684 * tty_ldiscs_lock from called functions
685 * termios_rwsem resetting termios data
686 * tasklist_lock to walk task list for hangup event
687 * ->siglock to protect ->signal/->sighand
689 static void __tty_hangup(struct tty_struct *tty, int exit_session)
691 struct file *cons_filp = NULL;
692 struct file *filp, *f = NULL;
693 struct tty_file_private *priv;
694 int closecount = 0, n;
701 spin_lock(&redirect_lock);
702 if (redirect && file_tty(redirect) == tty) {
706 spin_unlock(&redirect_lock);
710 if (test_bit(TTY_HUPPED, &tty->flags)) {
715 /* inuse_filps is protected by the single tty lock,
716 this really needs to change if we want to flush the
717 workqueue with the lock held */
718 check_tty_count(tty, "tty_hangup");
720 spin_lock(&tty->files_lock);
721 /* This breaks for file handles being sent over AF_UNIX sockets ? */
722 list_for_each_entry(priv, &tty->tty_files, list) {
724 if (filp->f_op->write == redirected_tty_write)
726 if (filp->f_op->write != tty_write)
729 __tty_fasync(-1, filp, 0); /* can't block */
730 filp->f_op = &hung_up_tty_fops;
732 spin_unlock(&tty->files_lock);
734 refs = tty_signal_session_leader(tty, exit_session);
735 /* Account for the p->signal references we killed */
739 tty_ldisc_hangup(tty, cons_filp != NULL);
741 spin_lock_irq(&tty->ctrl_lock);
742 clear_bit(TTY_THROTTLED, &tty->flags);
743 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
744 put_pid(tty->session);
748 tty->ctrl_status = 0;
749 spin_unlock_irq(&tty->ctrl_lock);
752 * If one of the devices matches a console pointer, we
753 * cannot just call hangup() because that will cause
754 * tty->count and state->count to go out of sync.
755 * So we just call close() the right number of times.
759 for (n = 0; n < closecount; n++)
760 tty->ops->close(tty, cons_filp);
761 } else if (tty->ops->hangup)
762 tty->ops->hangup(tty);
764 * We don't want to have driver/ldisc interactions beyond the ones
765 * we did here. The driver layer expects no calls after ->hangup()
766 * from the ldisc side, which is now guaranteed.
768 set_bit(TTY_HUPPED, &tty->flags);
775 static void do_tty_hangup(struct work_struct *work)
777 struct tty_struct *tty =
778 container_of(work, struct tty_struct, hangup_work);
780 __tty_hangup(tty, 0);
784 * tty_hangup - trigger a hangup event
785 * @tty: tty to hangup
787 * A carrier loss (virtual or otherwise) has occurred on this like
788 * schedule a hangup sequence to run after this event.
791 void tty_hangup(struct tty_struct *tty)
793 tty_debug_hangup(tty, "hangup\n");
794 schedule_work(&tty->hangup_work);
797 EXPORT_SYMBOL(tty_hangup);
800 * tty_vhangup - process vhangup
801 * @tty: tty to hangup
803 * The user has asked via system call for the terminal to be hung up.
804 * We do this synchronously so that when the syscall returns the process
805 * is complete. That guarantee is necessary for security reasons.
808 void tty_vhangup(struct tty_struct *tty)
810 tty_debug_hangup(tty, "vhangup\n");
811 __tty_hangup(tty, 0);
814 EXPORT_SYMBOL(tty_vhangup);
818 * tty_vhangup_self - process vhangup for own ctty
820 * Perform a vhangup on the current controlling tty
823 void tty_vhangup_self(void)
825 struct tty_struct *tty;
827 tty = get_current_tty();
835 * tty_vhangup_session - hangup session leader exit
836 * @tty: tty to hangup
838 * The session leader is exiting and hanging up its controlling terminal.
839 * Every process in the foreground process group is signalled SIGHUP.
841 * We do this synchronously so that when the syscall returns the process
842 * is complete. That guarantee is necessary for security reasons.
845 static void tty_vhangup_session(struct tty_struct *tty)
847 tty_debug_hangup(tty, "session hangup\n");
848 __tty_hangup(tty, 1);
852 * tty_hung_up_p - was tty hung up
853 * @filp: file pointer of tty
855 * Return true if the tty has been subject to a vhangup or a carrier
859 int tty_hung_up_p(struct file *filp)
861 return (filp->f_op == &hung_up_tty_fops);
864 EXPORT_SYMBOL(tty_hung_up_p);
867 * disassociate_ctty - disconnect controlling tty
868 * @on_exit: true if exiting so need to "hang up" the session
870 * This function is typically called only by the session leader, when
871 * it wants to disassociate itself from its controlling tty.
873 * It performs the following functions:
874 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
875 * (2) Clears the tty from being controlling the session
876 * (3) Clears the controlling tty for all processes in the
879 * The argument on_exit is set to 1 if called when a process is
880 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
883 * BTM is taken for hysterical raisins, and held when
884 * called from no_tty().
885 * tty_mutex is taken to protect tty
886 * ->siglock is taken to protect ->signal/->sighand
887 * tasklist_lock is taken to walk process list for sessions
888 * ->siglock is taken to protect ->signal/->sighand
891 void disassociate_ctty(int on_exit)
893 struct tty_struct *tty;
895 if (!current->signal->leader)
898 tty = get_current_tty();
900 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
901 tty_vhangup_session(tty);
903 struct pid *tty_pgrp = tty_get_pgrp(tty);
905 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
907 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
913 } else if (on_exit) {
914 struct pid *old_pgrp;
915 spin_lock_irq(¤t->sighand->siglock);
916 old_pgrp = current->signal->tty_old_pgrp;
917 current->signal->tty_old_pgrp = NULL;
918 spin_unlock_irq(¤t->sighand->siglock);
920 kill_pgrp(old_pgrp, SIGHUP, on_exit);
921 kill_pgrp(old_pgrp, SIGCONT, on_exit);
927 spin_lock_irq(¤t->sighand->siglock);
928 put_pid(current->signal->tty_old_pgrp);
929 current->signal->tty_old_pgrp = NULL;
931 tty = tty_kref_get(current->signal->tty);
934 spin_lock_irqsave(&tty->ctrl_lock, flags);
935 put_pid(tty->session);
939 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
942 tty_debug_hangup(tty, "no current tty\n");
944 spin_unlock_irq(¤t->sighand->siglock);
945 /* Now clear signal->tty under the lock */
946 read_lock(&tasklist_lock);
947 session_clear_tty(task_session(current));
948 read_unlock(&tasklist_lock);
953 * no_tty - Ensure the current process does not have a controlling tty
957 /* FIXME: Review locking here. The tty_lock never covered any race
958 between a new association and proc_clear_tty but possible we need
959 to protect against this anyway */
960 struct task_struct *tsk = current;
961 disassociate_ctty(0);
967 * stop_tty - propagate flow control
970 * Perform flow control to the driver. May be called
971 * on an already stopped device and will not re-call the driver
974 * This functionality is used by both the line disciplines for
975 * halting incoming flow and by the driver. It may therefore be
976 * called from any context, may be under the tty atomic_write_lock
983 void __stop_tty(struct tty_struct *tty)
992 void stop_tty(struct tty_struct *tty)
996 spin_lock_irqsave(&tty->flow_lock, flags);
998 spin_unlock_irqrestore(&tty->flow_lock, flags);
1000 EXPORT_SYMBOL(stop_tty);
1003 * start_tty - propagate flow control
1004 * @tty: tty to start
1006 * Start a tty that has been stopped if at all possible. If this
1007 * tty was previous stopped and is now being started, the driver
1008 * start method is invoked and the line discipline woken.
1014 void __start_tty(struct tty_struct *tty)
1016 if (!tty->stopped || tty->flow_stopped)
1019 if (tty->ops->start)
1020 tty->ops->start(tty);
1024 void start_tty(struct tty_struct *tty)
1026 unsigned long flags;
1028 spin_lock_irqsave(&tty->flow_lock, flags);
1030 spin_unlock_irqrestore(&tty->flow_lock, flags);
1032 EXPORT_SYMBOL(start_tty);
1034 static void tty_update_time(struct timespec *time)
1036 unsigned long sec = get_seconds();
1039 * We only care if the two values differ in anything other than the
1040 * lower three bits (i.e every 8 seconds). If so, then we can update
1041 * the time of the tty device, otherwise it could be construded as a
1042 * security leak to let userspace know the exact timing of the tty.
1044 if ((sec ^ time->tv_sec) & ~7)
1049 * tty_read - read method for tty device files
1050 * @file: pointer to tty file
1052 * @count: size of user buffer
1055 * Perform the read system call function on this terminal device. Checks
1056 * for hung up devices before calling the line discipline method.
1059 * Locks the line discipline internally while needed. Multiple
1060 * read calls may be outstanding in parallel.
1063 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1067 struct inode *inode = file_inode(file);
1068 struct tty_struct *tty = file_tty(file);
1069 struct tty_ldisc *ld;
1071 if (tty_paranoia_check(tty, inode, "tty_read"))
1073 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1076 /* We want to wait for the line discipline to sort out in this
1078 ld = tty_ldisc_ref_wait(tty);
1080 return hung_up_tty_read(file, buf, count, ppos);
1082 i = ld->ops->read(tty, file, buf, count);
1085 tty_ldisc_deref(ld);
1088 tty_update_time(&inode->i_atime);
1093 static void tty_write_unlock(struct tty_struct *tty)
1095 mutex_unlock(&tty->atomic_write_lock);
1096 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1099 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1101 if (!mutex_trylock(&tty->atomic_write_lock)) {
1104 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1105 return -ERESTARTSYS;
1111 * Split writes up in sane blocksizes to avoid
1112 * denial-of-service type attacks
1114 static inline ssize_t do_tty_write(
1115 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1116 struct tty_struct *tty,
1118 const char __user *buf,
1121 ssize_t ret, written = 0;
1124 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1129 * We chunk up writes into a temporary buffer. This
1130 * simplifies low-level drivers immensely, since they
1131 * don't have locking issues and user mode accesses.
1133 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1136 * The default chunk-size is 2kB, because the NTTY
1137 * layer has problems with bigger chunks. It will
1138 * claim to be able to handle more characters than
1141 * FIXME: This can probably go away now except that 64K chunks
1142 * are too likely to fail unless switched to vmalloc...
1145 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1150 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1151 if (tty->write_cnt < chunk) {
1152 unsigned char *buf_chunk;
1157 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1162 kfree(tty->write_buf);
1163 tty->write_cnt = chunk;
1164 tty->write_buf = buf_chunk;
1167 /* Do the write .. */
1169 size_t size = count;
1173 if (copy_from_user(tty->write_buf, buf, size))
1175 ret = write(tty, file, tty->write_buf, size);
1184 if (signal_pending(current))
1189 tty_update_time(&file_inode(file)->i_mtime);
1193 tty_write_unlock(tty);
1198 * tty_write_message - write a message to a certain tty, not just the console.
1199 * @tty: the destination tty_struct
1200 * @msg: the message to write
1202 * This is used for messages that need to be redirected to a specific tty.
1203 * We don't put it into the syslog queue right now maybe in the future if
1206 * We must still hold the BTM and test the CLOSING flag for the moment.
1209 void tty_write_message(struct tty_struct *tty, char *msg)
1212 mutex_lock(&tty->atomic_write_lock);
1214 if (tty->ops->write && tty->count > 0)
1215 tty->ops->write(tty, msg, strlen(msg));
1217 tty_write_unlock(tty);
1224 * tty_write - write method for tty device file
1225 * @file: tty file pointer
1226 * @buf: user data to write
1227 * @count: bytes to write
1230 * Write data to a tty device via the line discipline.
1233 * Locks the line discipline as required
1234 * Writes to the tty driver are serialized by the atomic_write_lock
1235 * and are then processed in chunks to the device. The line discipline
1236 * write method will not be invoked in parallel for each device.
1239 static ssize_t tty_write(struct file *file, const char __user *buf,
1240 size_t count, loff_t *ppos)
1242 struct tty_struct *tty = file_tty(file);
1243 struct tty_ldisc *ld;
1246 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1248 if (!tty || !tty->ops->write ||
1249 (test_bit(TTY_IO_ERROR, &tty->flags)))
1251 /* Short term debug to catch buggy drivers */
1252 if (tty->ops->write_room == NULL)
1253 tty_err(tty, "missing write_room method\n");
1254 ld = tty_ldisc_ref_wait(tty);
1256 return hung_up_tty_write(file, buf, count, ppos);
1257 if (!ld->ops->write)
1260 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1261 tty_ldisc_deref(ld);
1265 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1266 size_t count, loff_t *ppos)
1268 struct file *p = NULL;
1270 spin_lock(&redirect_lock);
1272 p = get_file(redirect);
1273 spin_unlock(&redirect_lock);
1277 res = vfs_write(p, buf, count, &p->f_pos);
1281 return tty_write(file, buf, count, ppos);
1285 * tty_send_xchar - send priority character
1287 * Send a high priority character to the tty even if stopped
1289 * Locking: none for xchar method, write ordering for write method.
1292 int tty_send_xchar(struct tty_struct *tty, char ch)
1294 int was_stopped = tty->stopped;
1296 if (tty->ops->send_xchar) {
1297 down_read(&tty->termios_rwsem);
1298 tty->ops->send_xchar(tty, ch);
1299 up_read(&tty->termios_rwsem);
1303 if (tty_write_lock(tty, 0) < 0)
1304 return -ERESTARTSYS;
1306 down_read(&tty->termios_rwsem);
1309 tty->ops->write(tty, &ch, 1);
1312 up_read(&tty->termios_rwsem);
1313 tty_write_unlock(tty);
1317 static char ptychar[] = "pqrstuvwxyzabcde";
1320 * pty_line_name - generate name for a pty
1321 * @driver: the tty driver in use
1322 * @index: the minor number
1323 * @p: output buffer of at least 6 bytes
1325 * Generate a name from a driver reference and write it to the output
1330 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1332 int i = index + driver->name_base;
1333 /* ->name is initialized to "ttyp", but "tty" is expected */
1334 sprintf(p, "%s%c%x",
1335 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1336 ptychar[i >> 4 & 0xf], i & 0xf);
1340 * tty_line_name - generate name for a tty
1341 * @driver: the tty driver in use
1342 * @index: the minor number
1343 * @p: output buffer of at least 7 bytes
1345 * Generate a name from a driver reference and write it to the output
1350 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1352 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1353 return sprintf(p, "%s", driver->name);
1355 return sprintf(p, "%s%d", driver->name,
1356 index + driver->name_base);
1360 * tty_driver_lookup_tty() - find an existing tty, if any
1361 * @driver: the driver for the tty
1362 * @idx: the minor number
1364 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1365 * driver lookup() method returns an error.
1367 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1369 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1370 struct file *file, int idx)
1372 struct tty_struct *tty;
1374 if (driver->ops->lookup)
1375 tty = driver->ops->lookup(driver, file, idx);
1377 tty = driver->ttys[idx];
1385 * tty_init_termios - helper for termios setup
1386 * @tty: the tty to set up
1388 * Initialise the termios structures for this tty. Thus runs under
1389 * the tty_mutex currently so we can be relaxed about ordering.
1392 void tty_init_termios(struct tty_struct *tty)
1394 struct ktermios *tp;
1395 int idx = tty->index;
1397 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1398 tty->termios = tty->driver->init_termios;
1400 /* Check for lazy saved data */
1401 tp = tty->driver->termios[idx];
1404 tty->termios.c_line = tty->driver->init_termios.c_line;
1406 tty->termios = tty->driver->init_termios;
1408 /* Compatibility until drivers always set this */
1409 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1410 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1412 EXPORT_SYMBOL_GPL(tty_init_termios);
1414 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1416 tty_init_termios(tty);
1417 tty_driver_kref_get(driver);
1419 driver->ttys[tty->index] = tty;
1422 EXPORT_SYMBOL_GPL(tty_standard_install);
1425 * tty_driver_install_tty() - install a tty entry in the driver
1426 * @driver: the driver for the tty
1429 * Install a tty object into the driver tables. The tty->index field
1430 * will be set by the time this is called. This method is responsible
1431 * for ensuring any need additional structures are allocated and
1434 * Locking: tty_mutex for now
1436 static int tty_driver_install_tty(struct tty_driver *driver,
1437 struct tty_struct *tty)
1439 return driver->ops->install ? driver->ops->install(driver, tty) :
1440 tty_standard_install(driver, tty);
1444 * tty_driver_remove_tty() - remove a tty from the driver tables
1445 * @driver: the driver for the tty
1446 * @idx: the minor number
1448 * Remvoe a tty object from the driver tables. The tty->index field
1449 * will be set by the time this is called.
1451 * Locking: tty_mutex for now
1453 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1455 if (driver->ops->remove)
1456 driver->ops->remove(driver, tty);
1458 driver->ttys[tty->index] = NULL;
1462 * tty_reopen() - fast re-open of an open tty
1463 * @tty - the tty to open
1465 * Return 0 on success, -errno on error.
1466 * Re-opens on master ptys are not allowed and return -EIO.
1468 * Locking: Caller must hold tty_lock
1470 static int tty_reopen(struct tty_struct *tty)
1472 struct tty_driver *driver = tty->driver;
1474 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1475 driver->subtype == PTY_TYPE_MASTER)
1481 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1487 return tty_ldisc_reinit(tty, tty->termios.c_line);
1493 * tty_init_dev - initialise a tty device
1494 * @driver: tty driver we are opening a device on
1495 * @idx: device index
1496 * @ret_tty: returned tty structure
1498 * Prepare a tty device. This may not be a "new" clean device but
1499 * could also be an active device. The pty drivers require special
1500 * handling because of this.
1503 * The function is called under the tty_mutex, which
1504 * protects us from the tty struct or driver itself going away.
1506 * On exit the tty device has the line discipline attached and
1507 * a reference count of 1. If a pair was created for pty/tty use
1508 * and the other was a pty master then it too has a reference count of 1.
1510 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1511 * failed open. The new code protects the open with a mutex, so it's
1512 * really quite straightforward. The mutex locking can probably be
1513 * relaxed for the (most common) case of reopening a tty.
1516 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1518 struct tty_struct *tty;
1522 * First time open is complex, especially for PTY devices.
1523 * This code guarantees that either everything succeeds and the
1524 * TTY is ready for operation, or else the table slots are vacated
1525 * and the allocated memory released. (Except that the termios
1526 * and locked termios may be retained.)
1529 if (!try_module_get(driver->owner))
1530 return ERR_PTR(-ENODEV);
1532 tty = alloc_tty_struct(driver, idx);
1535 goto err_module_put;
1539 retval = tty_driver_install_tty(driver, tty);
1544 tty->port = driver->ports[idx];
1546 WARN_RATELIMIT(!tty->port,
1547 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1548 __func__, tty->driver->name);
1550 tty->port->itty = tty;
1553 * Structures all installed ... call the ldisc open routines.
1554 * If we fail here just call release_tty to clean up. No need
1555 * to decrement the use counts, as release_tty doesn't care.
1557 retval = tty_ldisc_setup(tty, tty->link);
1559 goto err_release_tty;
1560 /* Return the tty locked so that it cannot vanish under the caller */
1565 free_tty_struct(tty);
1567 module_put(driver->owner);
1568 return ERR_PTR(retval);
1570 /* call the tty release_tty routine to clean out this slot */
1573 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1575 release_tty(tty, idx);
1576 return ERR_PTR(retval);
1579 static void tty_free_termios(struct tty_struct *tty)
1581 struct ktermios *tp;
1582 int idx = tty->index;
1584 /* If the port is going to reset then it has no termios to save */
1585 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1588 /* Stash the termios data */
1589 tp = tty->driver->termios[idx];
1591 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1594 tty->driver->termios[idx] = tp;
1600 * tty_flush_works - flush all works of a tty/pty pair
1601 * @tty: tty device to flush works for (or either end of a pty pair)
1603 * Sync flush all works belonging to @tty (and the 'other' tty).
1605 static void tty_flush_works(struct tty_struct *tty)
1607 flush_work(&tty->SAK_work);
1608 flush_work(&tty->hangup_work);
1610 flush_work(&tty->link->SAK_work);
1611 flush_work(&tty->link->hangup_work);
1616 * release_one_tty - release tty structure memory
1617 * @kref: kref of tty we are obliterating
1619 * Releases memory associated with a tty structure, and clears out the
1620 * driver table slots. This function is called when a device is no longer
1621 * in use. It also gets called when setup of a device fails.
1624 * takes the file list lock internally when working on the list
1625 * of ttys that the driver keeps.
1627 * This method gets called from a work queue so that the driver private
1628 * cleanup ops can sleep (needed for USB at least)
1630 static void release_one_tty(struct work_struct *work)
1632 struct tty_struct *tty =
1633 container_of(work, struct tty_struct, hangup_work);
1634 struct tty_driver *driver = tty->driver;
1635 struct module *owner = driver->owner;
1637 if (tty->ops->cleanup)
1638 tty->ops->cleanup(tty);
1641 tty_driver_kref_put(driver);
1644 spin_lock(&tty->files_lock);
1645 list_del_init(&tty->tty_files);
1646 spin_unlock(&tty->files_lock);
1649 put_pid(tty->session);
1650 free_tty_struct(tty);
1653 static void queue_release_one_tty(struct kref *kref)
1655 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1657 /* The hangup queue is now free so we can reuse it rather than
1658 waste a chunk of memory for each port */
1659 INIT_WORK(&tty->hangup_work, release_one_tty);
1660 schedule_work(&tty->hangup_work);
1664 * tty_kref_put - release a tty kref
1667 * Release a reference to a tty device and if need be let the kref
1668 * layer destruct the object for us
1671 void tty_kref_put(struct tty_struct *tty)
1674 kref_put(&tty->kref, queue_release_one_tty);
1676 EXPORT_SYMBOL(tty_kref_put);
1679 * release_tty - release tty structure memory
1681 * Release both @tty and a possible linked partner (think pty pair),
1682 * and decrement the refcount of the backing module.
1686 * takes the file list lock internally when working on the list
1687 * of ttys that the driver keeps.
1690 static void release_tty(struct tty_struct *tty, int idx)
1692 /* This should always be true but check for the moment */
1693 WARN_ON(tty->index != idx);
1694 WARN_ON(!mutex_is_locked(&tty_mutex));
1695 if (tty->ops->shutdown)
1696 tty->ops->shutdown(tty);
1697 tty_free_termios(tty);
1698 tty_driver_remove_tty(tty->driver, tty);
1699 tty->port->itty = NULL;
1701 tty->link->port->itty = NULL;
1702 tty_buffer_cancel_work(tty->port);
1704 tty_kref_put(tty->link);
1709 * tty_release_checks - check a tty before real release
1710 * @tty: tty to check
1711 * @o_tty: link of @tty (if any)
1712 * @idx: index of the tty
1714 * Performs some paranoid checking before true release of the @tty.
1715 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1717 static int tty_release_checks(struct tty_struct *tty, int idx)
1719 #ifdef TTY_PARANOIA_CHECK
1720 if (idx < 0 || idx >= tty->driver->num) {
1721 tty_debug(tty, "bad idx %d\n", idx);
1725 /* not much to check for devpts */
1726 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1729 if (tty != tty->driver->ttys[idx]) {
1730 tty_debug(tty, "bad driver table[%d] = %p\n",
1731 idx, tty->driver->ttys[idx]);
1734 if (tty->driver->other) {
1735 struct tty_struct *o_tty = tty->link;
1737 if (o_tty != tty->driver->other->ttys[idx]) {
1738 tty_debug(tty, "bad other table[%d] = %p\n",
1739 idx, tty->driver->other->ttys[idx]);
1742 if (o_tty->link != tty) {
1743 tty_debug(tty, "bad link = %p\n", o_tty->link);
1752 * tty_release - vfs callback for close
1753 * @inode: inode of tty
1754 * @filp: file pointer for handle to tty
1756 * Called the last time each file handle is closed that references
1757 * this tty. There may however be several such references.
1760 * Takes bkl. See tty_release_dev
1762 * Even releasing the tty structures is a tricky business.. We have
1763 * to be very careful that the structures are all released at the
1764 * same time, as interrupts might otherwise get the wrong pointers.
1766 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1767 * lead to double frees or releasing memory still in use.
1770 int tty_release(struct inode *inode, struct file *filp)
1772 struct tty_struct *tty = file_tty(filp);
1773 struct tty_struct *o_tty = NULL;
1774 int do_sleep, final;
1779 if (tty_paranoia_check(tty, inode, __func__))
1783 check_tty_count(tty, __func__);
1785 __tty_fasync(-1, filp, 0);
1788 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1789 tty->driver->subtype == PTY_TYPE_MASTER)
1792 if (tty_release_checks(tty, idx)) {
1797 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1799 if (tty->ops->close)
1800 tty->ops->close(tty, filp);
1802 /* If tty is pty master, lock the slave pty (stable lock order) */
1803 tty_lock_slave(o_tty);
1806 * Sanity check: if tty->count is going to zero, there shouldn't be
1807 * any waiters on tty->read_wait or tty->write_wait. We test the
1808 * wait queues and kick everyone out _before_ actually starting to
1809 * close. This ensures that we won't block while releasing the tty
1812 * The test for the o_tty closing is necessary, since the master and
1813 * slave sides may close in any order. If the slave side closes out
1814 * first, its count will be one, since the master side holds an open.
1815 * Thus this test wouldn't be triggered at the time the slave closed,
1821 if (tty->count <= 1) {
1822 if (waitqueue_active(&tty->read_wait)) {
1823 wake_up_poll(&tty->read_wait, POLLIN);
1826 if (waitqueue_active(&tty->write_wait)) {
1827 wake_up_poll(&tty->write_wait, POLLOUT);
1831 if (o_tty && o_tty->count <= 1) {
1832 if (waitqueue_active(&o_tty->read_wait)) {
1833 wake_up_poll(&o_tty->read_wait, POLLIN);
1836 if (waitqueue_active(&o_tty->write_wait)) {
1837 wake_up_poll(&o_tty->write_wait, POLLOUT);
1846 tty_warn(tty, "read/write wait queue active!\n");
1848 schedule_timeout_killable(timeout);
1849 if (timeout < 120 * HZ)
1850 timeout = 2 * timeout + 1;
1852 timeout = MAX_SCHEDULE_TIMEOUT;
1856 if (--o_tty->count < 0) {
1857 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1861 if (--tty->count < 0) {
1862 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1867 * We've decremented tty->count, so we need to remove this file
1868 * descriptor off the tty->tty_files list; this serves two
1870 * - check_tty_count sees the correct number of file descriptors
1871 * associated with this tty.
1872 * - do_tty_hangup no longer sees this file descriptor as
1873 * something that needs to be handled for hangups.
1878 * Perform some housekeeping before deciding whether to return.
1880 * If _either_ side is closing, make sure there aren't any
1881 * processes that still think tty or o_tty is their controlling
1885 read_lock(&tasklist_lock);
1886 session_clear_tty(tty->session);
1888 session_clear_tty(o_tty->session);
1889 read_unlock(&tasklist_lock);
1892 /* check whether both sides are closing ... */
1893 final = !tty->count && !(o_tty && o_tty->count);
1895 tty_unlock_slave(o_tty);
1898 /* At this point, the tty->count == 0 should ensure a dead tty
1899 cannot be re-opened by a racing opener */
1904 tty_debug_hangup(tty, "final close\n");
1906 * Ask the line discipline code to release its structures
1908 tty_ldisc_release(tty);
1910 /* Wait for pending work before tty destruction commmences */
1911 tty_flush_works(tty);
1913 tty_debug_hangup(tty, "freeing structure\n");
1915 * The release_tty function takes care of the details of clearing
1916 * the slots and preserving the termios structure. The tty_unlock_pair
1917 * should be safe as we keep a kref while the tty is locked (so the
1918 * unlock never unlocks a freed tty).
1920 mutex_lock(&tty_mutex);
1921 release_tty(tty, idx);
1922 mutex_unlock(&tty_mutex);
1928 * tty_open_current_tty - get locked tty of current task
1929 * @device: device number
1930 * @filp: file pointer to tty
1931 * @return: locked tty of the current task iff @device is /dev/tty
1933 * Performs a re-open of the current task's controlling tty.
1935 * We cannot return driver and index like for the other nodes because
1936 * devpts will not work then. It expects inodes to be from devpts FS.
1938 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1940 struct tty_struct *tty;
1943 if (device != MKDEV(TTYAUX_MAJOR, 0))
1946 tty = get_current_tty();
1948 return ERR_PTR(-ENXIO);
1950 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1953 tty_kref_put(tty); /* safe to drop the kref now */
1955 retval = tty_reopen(tty);
1958 tty = ERR_PTR(retval);
1964 * tty_lookup_driver - lookup a tty driver for a given device file
1965 * @device: device number
1966 * @filp: file pointer to tty
1967 * @noctty: set if the device should not become a controlling tty
1968 * @index: index for the device in the @return driver
1969 * @return: driver for this inode (with increased refcount)
1971 * If @return is not erroneous, the caller is responsible to decrement the
1972 * refcount by tty_driver_kref_put.
1974 * Locking: tty_mutex protects get_tty_driver
1976 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1979 struct tty_driver *driver;
1983 case MKDEV(TTY_MAJOR, 0): {
1984 extern struct tty_driver *console_driver;
1985 driver = tty_driver_kref_get(console_driver);
1986 *index = fg_console;
1990 case MKDEV(TTYAUX_MAJOR, 1): {
1991 struct tty_driver *console_driver = console_device(index);
1992 if (console_driver) {
1993 driver = tty_driver_kref_get(console_driver);
1995 /* Don't let /dev/console block */
1996 filp->f_flags |= O_NONBLOCK;
2000 return ERR_PTR(-ENODEV);
2003 driver = get_tty_driver(device, index);
2005 return ERR_PTR(-ENODEV);
2012 * tty_open_by_driver - open a tty device
2013 * @device: dev_t of device to open
2014 * @inode: inode of device file
2015 * @filp: file pointer to tty
2017 * Performs the driver lookup, checks for a reopen, or otherwise
2018 * performs the first-time tty initialization.
2020 * Returns the locked initialized or re-opened &tty_struct
2022 * Claims the global tty_mutex to serialize:
2023 * - concurrent first-time tty initialization
2024 * - concurrent tty driver removal w/ lookup
2025 * - concurrent tty removal from driver table
2027 static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
2030 struct tty_struct *tty;
2031 struct tty_driver *driver = NULL;
2035 mutex_lock(&tty_mutex);
2036 driver = tty_lookup_driver(device, filp, &index);
2037 if (IS_ERR(driver)) {
2038 mutex_unlock(&tty_mutex);
2039 return ERR_CAST(driver);
2042 /* check whether we're reopening an existing tty */
2043 tty = tty_driver_lookup_tty(driver, filp, index);
2045 mutex_unlock(&tty_mutex);
2050 mutex_unlock(&tty_mutex);
2051 retval = tty_lock_interruptible(tty);
2052 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2054 if (retval == -EINTR)
2055 retval = -ERESTARTSYS;
2056 tty = ERR_PTR(retval);
2059 retval = tty_reopen(tty);
2062 tty = ERR_PTR(retval);
2064 } else { /* Returns with the tty_lock held for now */
2065 tty = tty_init_dev(driver, index);
2066 mutex_unlock(&tty_mutex);
2069 tty_driver_kref_put(driver);
2074 * tty_open - open a tty device
2075 * @inode: inode of device file
2076 * @filp: file pointer to tty
2078 * tty_open and tty_release keep up the tty count that contains the
2079 * number of opens done on a tty. We cannot use the inode-count, as
2080 * different inodes might point to the same tty.
2082 * Open-counting is needed for pty masters, as well as for keeping
2083 * track of serial lines: DTR is dropped when the last close happens.
2084 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2086 * The termios state of a pty is reset on first open so that
2087 * settings don't persist across reuse.
2089 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2090 * tty->count should protect the rest.
2091 * ->siglock protects ->signal/->sighand
2093 * Note: the tty_unlock/lock cases without a ref are only safe due to
2097 static int tty_open(struct inode *inode, struct file *filp)
2099 struct tty_struct *tty;
2101 dev_t device = inode->i_rdev;
2102 unsigned saved_flags = filp->f_flags;
2104 nonseekable_open(inode, filp);
2107 retval = tty_alloc_file(filp);
2111 tty = tty_open_current_tty(device, filp);
2113 tty = tty_open_by_driver(device, inode, filp);
2116 tty_free_file(filp);
2117 retval = PTR_ERR(tty);
2118 if (retval != -EAGAIN || signal_pending(current))
2124 tty_add_file(tty, filp);
2126 check_tty_count(tty, __func__);
2127 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2130 retval = tty->ops->open(tty, filp);
2133 filp->f_flags = saved_flags;
2136 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2138 tty_unlock(tty); /* need to call tty_release without BTM */
2139 tty_release(inode, filp);
2140 if (retval != -ERESTARTSYS)
2143 if (signal_pending(current))
2148 * Need to reset f_op in case a hangup happened.
2150 if (tty_hung_up_p(filp))
2151 filp->f_op = &tty_fops;
2154 clear_bit(TTY_HUPPED, &tty->flags);
2157 read_lock(&tasklist_lock);
2158 spin_lock_irq(¤t->sighand->siglock);
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);
2166 current->signal->leader &&
2167 !current->signal->tty &&
2168 tty->session == NULL) {
2170 * Don't let a process that only has write access to the tty
2171 * obtain the privileges associated with having a tty as
2172 * controlling terminal (being able to reopen it with full
2173 * access through /dev/tty, being able to perform pushback).
2174 * Many distributions set the group of all ttys to "tty" and
2175 * grant write-only access to all terminals for setgid tty
2176 * binaries, which should not imply full privileges on all ttys.
2178 * This could theoretically break old code that performs open()
2179 * on a write-only file descriptor. In that case, it might be
2180 * necessary to also permit this if
2181 * inode_permission(inode, MAY_READ) == 0.
2183 if (filp->f_mode & FMODE_READ)
2184 __proc_set_tty(tty);
2186 spin_unlock_irq(¤t->sighand->siglock);
2187 read_unlock(&tasklist_lock);
2195 * tty_poll - check tty status
2196 * @filp: file being polled
2197 * @wait: poll wait structures to update
2199 * Call the line discipline polling method to obtain the poll
2200 * status of the device.
2202 * Locking: locks called line discipline but ldisc poll method
2203 * may be re-entered freely by other callers.
2206 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2208 struct tty_struct *tty = file_tty(filp);
2209 struct tty_ldisc *ld;
2212 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2215 ld = tty_ldisc_ref_wait(tty);
2217 return hung_up_tty_poll(filp, wait);
2219 ret = ld->ops->poll(tty, filp, wait);
2220 tty_ldisc_deref(ld);
2224 static int __tty_fasync(int fd, struct file *filp, int on)
2226 struct tty_struct *tty = file_tty(filp);
2227 unsigned long flags;
2230 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2233 retval = fasync_helper(fd, filp, on, &tty->fasync);
2241 spin_lock_irqsave(&tty->ctrl_lock, flags);
2244 type = PIDTYPE_PGID;
2246 pid = task_pid(current);
2250 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2251 __f_setown(filp, pid, type, 0);
2259 static int tty_fasync(int fd, struct file *filp, int on)
2261 struct tty_struct *tty = file_tty(filp);
2262 int retval = -ENOTTY;
2265 if (!tty_hung_up_p(filp))
2266 retval = __tty_fasync(fd, filp, on);
2273 * tiocsti - fake input character
2274 * @tty: tty to fake input into
2275 * @p: pointer to character
2277 * Fake input to a tty device. Does the necessary locking and
2280 * FIXME: does not honour flow control ??
2283 * Called functions take tty_ldiscs_lock
2284 * current->signal->tty check is safe without locks
2286 * FIXME: may race normal receive processing
2289 static int tiocsti(struct tty_struct *tty, char __user *p)
2292 struct tty_ldisc *ld;
2294 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2296 if (get_user(ch, p))
2298 tty_audit_tiocsti(tty, ch);
2299 ld = tty_ldisc_ref_wait(tty);
2302 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2303 tty_ldisc_deref(ld);
2308 * tiocgwinsz - implement window query ioctl
2310 * @arg: user buffer for result
2312 * Copies the kernel idea of the window size into the user buffer.
2314 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2318 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2322 mutex_lock(&tty->winsize_mutex);
2323 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2324 mutex_unlock(&tty->winsize_mutex);
2326 return err ? -EFAULT: 0;
2330 * tty_do_resize - resize event
2331 * @tty: tty being resized
2332 * @rows: rows (character)
2333 * @cols: cols (character)
2335 * Update the termios variables and send the necessary signals to
2336 * peform a terminal resize correctly
2339 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2344 mutex_lock(&tty->winsize_mutex);
2345 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2348 /* Signal the foreground process group */
2349 pgrp = tty_get_pgrp(tty);
2351 kill_pgrp(pgrp, SIGWINCH, 1);
2356 mutex_unlock(&tty->winsize_mutex);
2359 EXPORT_SYMBOL(tty_do_resize);
2362 * tiocswinsz - implement window size set ioctl
2363 * @tty; tty side of tty
2364 * @arg: user buffer for result
2366 * Copies the user idea of the window size to the kernel. Traditionally
2367 * this is just advisory information but for the Linux console it
2368 * actually has driver level meaning and triggers a VC resize.
2371 * Driver dependent. The default do_resize method takes the
2372 * tty termios mutex and ctrl_lock. The console takes its own lock
2373 * then calls into the default method.
2376 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2378 struct winsize tmp_ws;
2379 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2382 if (tty->ops->resize)
2383 return tty->ops->resize(tty, &tmp_ws);
2385 return tty_do_resize(tty, &tmp_ws);
2389 * tioccons - allow admin to move logical console
2390 * @file: the file to become console
2392 * Allow the administrator to move the redirected console device
2394 * Locking: uses redirect_lock to guard the redirect information
2397 static int tioccons(struct file *file)
2399 if (!capable(CAP_SYS_ADMIN))
2401 if (file->f_op->write == redirected_tty_write) {
2403 spin_lock(&redirect_lock);
2406 spin_unlock(&redirect_lock);
2411 spin_lock(&redirect_lock);
2413 spin_unlock(&redirect_lock);
2416 redirect = get_file(file);
2417 spin_unlock(&redirect_lock);
2422 * fionbio - non blocking ioctl
2423 * @file: file to set blocking value
2424 * @p: user parameter
2426 * Historical tty interfaces had a blocking control ioctl before
2427 * the generic functionality existed. This piece of history is preserved
2428 * in the expected tty API of posix OS's.
2430 * Locking: none, the open file handle ensures it won't go away.
2433 static int fionbio(struct file *file, int __user *p)
2437 if (get_user(nonblock, p))
2440 spin_lock(&file->f_lock);
2442 file->f_flags |= O_NONBLOCK;
2444 file->f_flags &= ~O_NONBLOCK;
2445 spin_unlock(&file->f_lock);
2450 * tiocsctty - set controlling tty
2451 * @tty: tty structure
2452 * @arg: user argument
2454 * This ioctl is used to manage job control. It permits a session
2455 * leader to set this tty as the controlling tty for the session.
2458 * Takes tty_lock() to serialize proc_set_tty() for this tty
2459 * Takes tasklist_lock internally to walk sessions
2460 * Takes ->siglock() when updating signal->tty
2463 static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2468 read_lock(&tasklist_lock);
2470 if (current->signal->leader && (task_session(current) == tty->session))
2474 * The process must be a session leader and
2475 * not have a controlling tty already.
2477 if (!current->signal->leader || current->signal->tty) {
2484 * This tty is already the controlling
2485 * tty for another session group!
2487 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2491 session_clear_tty(tty->session);
2498 /* See the comment in tty_open(). */
2499 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2506 read_unlock(&tasklist_lock);
2512 * tty_get_pgrp - return a ref counted pgrp pid
2515 * Returns a refcounted instance of the pid struct for the process
2516 * group controlling the tty.
2519 struct pid *tty_get_pgrp(struct tty_struct *tty)
2521 unsigned long flags;
2524 spin_lock_irqsave(&tty->ctrl_lock, flags);
2525 pgrp = get_pid(tty->pgrp);
2526 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2530 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2533 * This checks not only the pgrp, but falls back on the pid if no
2534 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2537 * The caller must hold rcu lock or the tasklist lock.
2539 static struct pid *session_of_pgrp(struct pid *pgrp)
2541 struct task_struct *p;
2542 struct pid *sid = NULL;
2544 p = pid_task(pgrp, PIDTYPE_PGID);
2546 p = pid_task(pgrp, PIDTYPE_PID);
2548 sid = task_session(p);
2554 * tiocgpgrp - get process group
2555 * @tty: tty passed by user
2556 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2559 * Obtain the process group of the tty. If there is no process group
2562 * Locking: none. Reference to current->signal->tty is safe.
2565 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2570 * (tty == real_tty) is a cheap way of
2571 * testing if the tty is NOT a master pty.
2573 if (tty == real_tty && current->signal->tty != real_tty)
2575 pid = tty_get_pgrp(real_tty);
2576 ret = put_user(pid_vnr(pid), p);
2582 * tiocspgrp - attempt to set process group
2583 * @tty: tty passed by user
2584 * @real_tty: tty side device matching tty passed by user
2587 * Set the process group of the tty to the session passed. Only
2588 * permitted where the tty session is our session.
2590 * Locking: RCU, ctrl lock
2593 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2597 int retval = tty_check_change(real_tty);
2603 if (!current->signal->tty ||
2604 (current->signal->tty != real_tty) ||
2605 (real_tty->session != task_session(current)))
2607 if (get_user(pgrp_nr, p))
2612 pgrp = find_vpid(pgrp_nr);
2617 if (session_of_pgrp(pgrp) != task_session(current))
2620 spin_lock_irq(&tty->ctrl_lock);
2621 put_pid(real_tty->pgrp);
2622 real_tty->pgrp = get_pid(pgrp);
2623 spin_unlock_irq(&tty->ctrl_lock);
2630 * tiocgsid - get session id
2631 * @tty: tty passed by user
2632 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2633 * @p: pointer to returned session id
2635 * Obtain the session id of the tty. If there is no session
2638 * Locking: none. Reference to current->signal->tty is safe.
2641 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2644 * (tty == real_tty) is a cheap way of
2645 * testing if the tty is NOT a master pty.
2647 if (tty == real_tty && current->signal->tty != real_tty)
2649 if (!real_tty->session)
2651 return put_user(pid_vnr(real_tty->session), p);
2655 * tiocsetd - set line discipline
2657 * @p: pointer to user data
2659 * Set the line discipline according to user request.
2661 * Locking: see tty_set_ldisc, this function is just a helper
2664 static int tiocsetd(struct tty_struct *tty, int __user *p)
2669 if (get_user(disc, p))
2672 ret = tty_set_ldisc(tty, disc);
2678 * tiocgetd - get line discipline
2680 * @p: pointer to user data
2682 * Retrieves the line discipline id directly from the ldisc.
2684 * Locking: waits for ldisc reference (in case the line discipline
2685 * is changing or the tty is being hungup)
2688 static int tiocgetd(struct tty_struct *tty, int __user *p)
2690 struct tty_ldisc *ld;
2693 ld = tty_ldisc_ref_wait(tty);
2696 ret = put_user(ld->ops->num, p);
2697 tty_ldisc_deref(ld);
2702 * send_break - performed time break
2703 * @tty: device to break on
2704 * @duration: timeout in mS
2706 * Perform a timed break on hardware that lacks its own driver level
2707 * timed break functionality.
2710 * atomic_write_lock serializes
2714 static int send_break(struct tty_struct *tty, unsigned int duration)
2718 if (tty->ops->break_ctl == NULL)
2721 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2722 retval = tty->ops->break_ctl(tty, duration);
2724 /* Do the work ourselves */
2725 if (tty_write_lock(tty, 0) < 0)
2727 retval = tty->ops->break_ctl(tty, -1);
2730 if (!signal_pending(current))
2731 msleep_interruptible(duration);
2732 retval = tty->ops->break_ctl(tty, 0);
2734 tty_write_unlock(tty);
2735 if (signal_pending(current))
2742 * tty_tiocmget - get modem status
2744 * @file: user file pointer
2745 * @p: pointer to result
2747 * Obtain the modem status bits from the tty driver if the feature
2748 * is supported. Return -EINVAL if it is not available.
2750 * Locking: none (up to the driver)
2753 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2755 int retval = -EINVAL;
2757 if (tty->ops->tiocmget) {
2758 retval = tty->ops->tiocmget(tty);
2761 retval = put_user(retval, p);
2767 * tty_tiocmset - set modem status
2769 * @cmd: command - clear bits, set bits or set all
2770 * @p: pointer to desired bits
2772 * Set the modem status bits from the tty driver if the feature
2773 * is supported. Return -EINVAL if it is not available.
2775 * Locking: none (up to the driver)
2778 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2782 unsigned int set, clear, val;
2784 if (tty->ops->tiocmset == NULL)
2787 retval = get_user(val, p);
2803 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2804 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2805 return tty->ops->tiocmset(tty, set, clear);
2808 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2810 int retval = -EINVAL;
2811 struct serial_icounter_struct icount;
2812 memset(&icount, 0, sizeof(icount));
2813 if (tty->ops->get_icount)
2814 retval = tty->ops->get_icount(tty, &icount);
2817 if (copy_to_user(arg, &icount, sizeof(icount)))
2822 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2824 static DEFINE_RATELIMIT_STATE(depr_flags,
2825 DEFAULT_RATELIMIT_INTERVAL,
2826 DEFAULT_RATELIMIT_BURST);
2827 char comm[TASK_COMM_LEN];
2830 if (get_user(flags, &ss->flags))
2833 flags &= ASYNC_DEPRECATED;
2835 if (flags && __ratelimit(&depr_flags))
2836 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2837 __func__, get_task_comm(comm, current), flags);
2841 * if pty, return the slave side (real_tty)
2842 * otherwise, return self
2844 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2846 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2847 tty->driver->subtype == PTY_TYPE_MASTER)
2853 * Split this up, as gcc can choke on it otherwise..
2855 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2857 struct tty_struct *tty = file_tty(file);
2858 struct tty_struct *real_tty;
2859 void __user *p = (void __user *)arg;
2861 struct tty_ldisc *ld;
2863 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2866 real_tty = tty_pair_get_tty(tty);
2869 * Factor out some common prep work
2877 retval = tty_check_change(tty);
2880 if (cmd != TIOCCBRK) {
2881 tty_wait_until_sent(tty, 0);
2882 if (signal_pending(current))
2893 return tiocsti(tty, p);
2895 return tiocgwinsz(real_tty, p);
2897 return tiocswinsz(real_tty, p);
2899 return real_tty != tty ? -EINVAL : tioccons(file);
2901 return fionbio(file, p);
2903 set_bit(TTY_EXCLUSIVE, &tty->flags);
2906 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2910 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2911 return put_user(excl, (int __user *)p);
2914 if (current->signal->tty != tty)
2919 return tiocsctty(real_tty, file, arg);
2921 return tiocgpgrp(tty, real_tty, p);
2923 return tiocspgrp(tty, real_tty, p);
2925 return tiocgsid(tty, real_tty, p);
2927 return tiocgetd(tty, p);
2929 return tiocsetd(tty, p);
2931 if (!capable(CAP_SYS_ADMIN))
2937 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2938 return put_user(ret, (unsigned int __user *)p);
2943 case TIOCSBRK: /* Turn break on, unconditionally */
2944 if (tty->ops->break_ctl)
2945 return tty->ops->break_ctl(tty, -1);
2947 case TIOCCBRK: /* Turn break off, unconditionally */
2948 if (tty->ops->break_ctl)
2949 return tty->ops->break_ctl(tty, 0);
2951 case TCSBRK: /* SVID version: non-zero arg --> no break */
2952 /* non-zero arg means wait for all output data
2953 * to be sent (performed above) but don't send break.
2954 * This is used by the tcdrain() termios function.
2957 return send_break(tty, 250);
2959 case TCSBRKP: /* support for POSIX tcsendbreak() */
2960 return send_break(tty, arg ? arg*100 : 250);
2963 return tty_tiocmget(tty, p);
2967 return tty_tiocmset(tty, cmd, p);
2969 retval = tty_tiocgicount(tty, p);
2970 /* For the moment allow fall through to the old method */
2971 if (retval != -EINVAL)
2978 /* flush tty buffer and allow ldisc to process ioctl */
2979 tty_buffer_flush(tty, NULL);
2984 tty_warn_deprecated_flags(p);
2987 if (tty->ops->ioctl) {
2988 retval = tty->ops->ioctl(tty, cmd, arg);
2989 if (retval != -ENOIOCTLCMD)
2992 ld = tty_ldisc_ref_wait(tty);
2994 return hung_up_tty_ioctl(file, cmd, arg);
2996 if (ld->ops->ioctl) {
2997 retval = ld->ops->ioctl(tty, file, cmd, arg);
2998 if (retval == -ENOIOCTLCMD)
3001 tty_ldisc_deref(ld);
3005 #ifdef CONFIG_COMPAT
3006 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
3009 struct tty_struct *tty = file_tty(file);
3010 struct tty_ldisc *ld;
3011 int retval = -ENOIOCTLCMD;
3013 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
3016 if (tty->ops->compat_ioctl) {
3017 retval = tty->ops->compat_ioctl(tty, cmd, arg);
3018 if (retval != -ENOIOCTLCMD)
3022 ld = tty_ldisc_ref_wait(tty);
3024 return hung_up_tty_compat_ioctl(file, cmd, arg);
3025 if (ld->ops->compat_ioctl)
3026 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
3028 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
3029 tty_ldisc_deref(ld);
3035 static int this_tty(const void *t, struct file *file, unsigned fd)
3037 if (likely(file->f_op->read != tty_read))
3039 return file_tty(file) != t ? 0 : fd + 1;
3043 * This implements the "Secure Attention Key" --- the idea is to
3044 * prevent trojan horses by killing all processes associated with this
3045 * tty when the user hits the "Secure Attention Key". Required for
3046 * super-paranoid applications --- see the Orange Book for more details.
3048 * This code could be nicer; ideally it should send a HUP, wait a few
3049 * seconds, then send a INT, and then a KILL signal. But you then
3050 * have to coordinate with the init process, since all processes associated
3051 * with the current tty must be dead before the new getty is allowed
3054 * Now, if it would be correct ;-/ The current code has a nasty hole -
3055 * it doesn't catch files in flight. We may send the descriptor to ourselves
3056 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3058 * Nasty bug: do_SAK is being called in interrupt context. This can
3059 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3061 void __do_SAK(struct tty_struct *tty)
3066 struct task_struct *g, *p;
3067 struct pid *session;
3072 session = tty->session;
3074 tty_ldisc_flush(tty);
3076 tty_driver_flush_buffer(tty);
3078 read_lock(&tasklist_lock);
3079 /* Kill the entire session */
3080 do_each_pid_task(session, PIDTYPE_SID, p) {
3081 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3082 task_pid_nr(p), p->comm);
3083 send_sig(SIGKILL, p, 1);
3084 } while_each_pid_task(session, PIDTYPE_SID, p);
3086 /* Now kill any processes that happen to have the tty open */
3087 do_each_thread(g, p) {
3088 if (p->signal->tty == tty) {
3089 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3090 task_pid_nr(p), p->comm);
3091 send_sig(SIGKILL, p, 1);
3095 i = iterate_fd(p->files, 0, this_tty, tty);
3097 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3098 task_pid_nr(p), p->comm, i - 1);
3099 force_sig(SIGKILL, p);
3102 } while_each_thread(g, p);
3103 read_unlock(&tasklist_lock);
3107 static void do_SAK_work(struct work_struct *work)
3109 struct tty_struct *tty =
3110 container_of(work, struct tty_struct, SAK_work);
3115 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3116 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3117 * the values which we write to it will be identical to the values which it
3118 * already has. --akpm
3120 void do_SAK(struct tty_struct *tty)
3124 schedule_work(&tty->SAK_work);
3127 EXPORT_SYMBOL(do_SAK);
3129 static int dev_match_devt(struct device *dev, const void *data)
3131 const dev_t *devt = data;
3132 return dev->devt == *devt;
3135 /* Must put_device() after it's unused! */
3136 static struct device *tty_get_device(struct tty_struct *tty)
3138 dev_t devt = tty_devnum(tty);
3139 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3146 * This subroutine allocates and initializes a tty structure.
3148 * Locking: none - tty in question is not exposed at this point
3151 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3153 struct tty_struct *tty;
3155 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3159 kref_init(&tty->kref);
3160 tty->magic = TTY_MAGIC;
3161 tty_ldisc_init(tty);
3162 tty->session = NULL;
3164 mutex_init(&tty->legacy_mutex);
3165 mutex_init(&tty->throttle_mutex);
3166 init_rwsem(&tty->termios_rwsem);
3167 mutex_init(&tty->winsize_mutex);
3168 init_ldsem(&tty->ldisc_sem);
3169 init_waitqueue_head(&tty->write_wait);
3170 init_waitqueue_head(&tty->read_wait);
3171 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3172 mutex_init(&tty->atomic_write_lock);
3173 spin_lock_init(&tty->ctrl_lock);
3174 spin_lock_init(&tty->flow_lock);
3175 spin_lock_init(&tty->files_lock);
3176 INIT_LIST_HEAD(&tty->tty_files);
3177 INIT_WORK(&tty->SAK_work, do_SAK_work);
3179 tty->driver = driver;
3180 tty->ops = driver->ops;
3182 tty_line_name(driver, idx, tty->name);
3183 tty->dev = tty_get_device(tty);
3189 * tty_put_char - write one character to a tty
3193 * Write one byte to the tty using the provided put_char method
3194 * if present. Returns the number of characters successfully output.
3196 * Note: the specific put_char operation in the driver layer may go
3197 * away soon. Don't call it directly, use this method
3200 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3202 if (tty->ops->put_char)
3203 return tty->ops->put_char(tty, ch);
3204 return tty->ops->write(tty, &ch, 1);
3206 EXPORT_SYMBOL_GPL(tty_put_char);
3208 struct class *tty_class;
3210 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3211 unsigned int index, unsigned int count)
3215 /* init here, since reused cdevs cause crashes */
3216 driver->cdevs[index] = cdev_alloc();
3217 if (!driver->cdevs[index])
3219 driver->cdevs[index]->ops = &tty_fops;
3220 driver->cdevs[index]->owner = driver->owner;
3221 err = cdev_add(driver->cdevs[index], dev, count);
3223 kobject_put(&driver->cdevs[index]->kobj);
3228 * tty_register_device - register a tty device
3229 * @driver: the tty driver that describes the tty device
3230 * @index: the index in the tty driver for this tty device
3231 * @device: a struct device that is associated with this tty device.
3232 * This field is optional, if there is no known struct device
3233 * for this tty device it can be set to NULL safely.
3235 * Returns a pointer to the struct device for this tty device
3236 * (or ERR_PTR(-EFOO) on error).
3238 * This call is required to be made to register an individual tty device
3239 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3240 * that bit is not set, this function should not be called by a tty
3246 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3247 struct device *device)
3249 return tty_register_device_attr(driver, index, device, NULL, NULL);
3251 EXPORT_SYMBOL(tty_register_device);
3253 static void tty_device_create_release(struct device *dev)
3255 dev_dbg(dev, "releasing...\n");
3260 * tty_register_device_attr - register a tty device
3261 * @driver: the tty driver that describes the tty device
3262 * @index: the index in the tty driver for this tty device
3263 * @device: a struct device that is associated with this tty device.
3264 * This field is optional, if there is no known struct device
3265 * for this tty device it can be set to NULL safely.
3266 * @drvdata: Driver data to be set to device.
3267 * @attr_grp: Attribute group to be set on device.
3269 * Returns a pointer to the struct device for this tty device
3270 * (or ERR_PTR(-EFOO) on error).
3272 * This call is required to be made to register an individual tty device
3273 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3274 * that bit is not set, this function should not be called by a tty
3279 struct device *tty_register_device_attr(struct tty_driver *driver,
3280 unsigned index, struct device *device,
3282 const struct attribute_group **attr_grp)
3285 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3286 struct device *dev = NULL;
3287 int retval = -ENODEV;
3290 if (index >= driver->num) {
3291 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3292 driver->name, index);
3293 return ERR_PTR(-EINVAL);
3296 if (driver->type == TTY_DRIVER_TYPE_PTY)
3297 pty_line_name(driver, index, name);
3299 tty_line_name(driver, index, name);
3301 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3302 retval = tty_cdev_add(driver, devt, index, 1);
3308 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3315 dev->class = tty_class;
3316 dev->parent = device;
3317 dev->release = tty_device_create_release;
3318 dev_set_name(dev, "%s", name);
3319 dev->groups = attr_grp;
3320 dev_set_drvdata(dev, drvdata);
3322 retval = device_register(dev);
3331 cdev_del(driver->cdevs[index]);
3332 driver->cdevs[index] = NULL;
3334 return ERR_PTR(retval);
3336 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3339 * tty_unregister_device - unregister a tty device
3340 * @driver: the tty driver that describes the tty device
3341 * @index: the index in the tty driver for this tty device
3343 * If a tty device is registered with a call to tty_register_device() then
3344 * this function must be called when the tty device is gone.
3349 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3351 device_destroy(tty_class,
3352 MKDEV(driver->major, driver->minor_start) + index);
3353 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3354 cdev_del(driver->cdevs[index]);
3355 driver->cdevs[index] = NULL;
3358 EXPORT_SYMBOL(tty_unregister_device);
3361 * __tty_alloc_driver -- allocate tty driver
3362 * @lines: count of lines this driver can handle at most
3363 * @owner: module which is repsonsible for this driver
3364 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3366 * This should not be called directly, some of the provided macros should be
3367 * used instead. Use IS_ERR and friends on @retval.
3369 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3370 unsigned long flags)
3372 struct tty_driver *driver;
3373 unsigned int cdevs = 1;
3376 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3377 return ERR_PTR(-EINVAL);
3379 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3381 return ERR_PTR(-ENOMEM);
3383 kref_init(&driver->kref);
3384 driver->magic = TTY_DRIVER_MAGIC;
3385 driver->num = lines;
3386 driver->owner = owner;
3387 driver->flags = flags;
3389 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3390 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3392 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3394 if (!driver->ttys || !driver->termios) {
3400 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3401 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3403 if (!driver->ports) {
3410 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3411 if (!driver->cdevs) {
3418 kfree(driver->ports);
3419 kfree(driver->ttys);
3420 kfree(driver->termios);
3421 kfree(driver->cdevs);
3423 return ERR_PTR(err);
3425 EXPORT_SYMBOL(__tty_alloc_driver);
3427 static void destruct_tty_driver(struct kref *kref)
3429 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3431 struct ktermios *tp;
3433 if (driver->flags & TTY_DRIVER_INSTALLED) {
3435 * Free the termios and termios_locked structures because
3436 * we don't want to get memory leaks when modular tty
3437 * drivers are removed from the kernel.
3439 for (i = 0; i < driver->num; i++) {
3440 tp = driver->termios[i];
3442 driver->termios[i] = NULL;
3445 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3446 tty_unregister_device(driver, i);
3448 proc_tty_unregister_driver(driver);
3449 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3450 cdev_del(driver->cdevs[0]);
3452 kfree(driver->cdevs);
3453 kfree(driver->ports);
3454 kfree(driver->termios);
3455 kfree(driver->ttys);
3459 void tty_driver_kref_put(struct tty_driver *driver)
3461 kref_put(&driver->kref, destruct_tty_driver);
3463 EXPORT_SYMBOL(tty_driver_kref_put);
3465 void tty_set_operations(struct tty_driver *driver,
3466 const struct tty_operations *op)
3470 EXPORT_SYMBOL(tty_set_operations);
3472 void put_tty_driver(struct tty_driver *d)
3474 tty_driver_kref_put(d);
3476 EXPORT_SYMBOL(put_tty_driver);
3479 * Called by a tty driver to register itself.
3481 int tty_register_driver(struct tty_driver *driver)
3488 if (!driver->major) {
3489 error = alloc_chrdev_region(&dev, driver->minor_start,
3490 driver->num, driver->name);
3492 driver->major = MAJOR(dev);
3493 driver->minor_start = MINOR(dev);
3496 dev = MKDEV(driver->major, driver->minor_start);
3497 error = register_chrdev_region(dev, driver->num, driver->name);
3502 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3503 error = tty_cdev_add(driver, dev, 0, driver->num);
3505 goto err_unreg_char;
3508 mutex_lock(&tty_mutex);
3509 list_add(&driver->tty_drivers, &tty_drivers);
3510 mutex_unlock(&tty_mutex);
3512 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3513 for (i = 0; i < driver->num; i++) {
3514 d = tty_register_device(driver, i, NULL);
3517 goto err_unreg_devs;
3521 proc_tty_register_driver(driver);
3522 driver->flags |= TTY_DRIVER_INSTALLED;
3526 for (i--; i >= 0; i--)
3527 tty_unregister_device(driver, i);
3529 mutex_lock(&tty_mutex);
3530 list_del(&driver->tty_drivers);
3531 mutex_unlock(&tty_mutex);
3534 unregister_chrdev_region(dev, driver->num);
3538 EXPORT_SYMBOL(tty_register_driver);
3541 * Called by a tty driver to unregister itself.
3543 int tty_unregister_driver(struct tty_driver *driver)
3547 if (driver->refcount)
3550 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3552 mutex_lock(&tty_mutex);
3553 list_del(&driver->tty_drivers);
3554 mutex_unlock(&tty_mutex);
3558 EXPORT_SYMBOL(tty_unregister_driver);
3560 dev_t tty_devnum(struct tty_struct *tty)
3562 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3564 EXPORT_SYMBOL(tty_devnum);
3566 void tty_default_fops(struct file_operations *fops)
3572 * Initialize the console device. This is called *early*, so
3573 * we can't necessarily depend on lots of kernel help here.
3574 * Just do some early initializations, and do the complex setup
3577 void __init console_init(void)
3581 /* Setup the default TTY line discipline. */
3585 * set up the console device so that later boot sequences can
3586 * inform about problems etc..
3588 call = __con_initcall_start;
3589 while (call < __con_initcall_end) {
3595 static char *tty_devnode(struct device *dev, umode_t *mode)
3599 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3600 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3605 static int __init tty_class_init(void)
3607 tty_class = class_create(THIS_MODULE, "tty");
3608 if (IS_ERR(tty_class))
3609 return PTR_ERR(tty_class);
3610 tty_class->devnode = tty_devnode;
3614 postcore_initcall(tty_class_init);
3616 /* 3/2004 jmc: why do these devices exist? */
3617 static struct cdev tty_cdev, console_cdev;
3619 static ssize_t show_cons_active(struct device *dev,
3620 struct device_attribute *attr, char *buf)
3622 struct console *cs[16];
3628 for_each_console(c) {
3633 if ((c->flags & CON_ENABLED) == 0)
3636 if (i >= ARRAY_SIZE(cs))
3640 int index = cs[i]->index;
3641 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3643 /* don't resolve tty0 as some programs depend on it */
3644 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3645 count += tty_line_name(drv, index, buf + count);
3647 count += sprintf(buf + count, "%s%d",
3648 cs[i]->name, cs[i]->index);
3650 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3656 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3658 static struct attribute *cons_dev_attrs[] = {
3659 &dev_attr_active.attr,
3663 ATTRIBUTE_GROUPS(cons_dev);
3665 static struct device *consdev;
3667 void console_sysfs_notify(void)
3670 sysfs_notify(&consdev->kobj, NULL, "active");
3674 * Ok, now we can initialize the rest of the tty devices and can count
3675 * on memory allocations, interrupts etc..
3677 int __init tty_init(void)
3679 cdev_init(&tty_cdev, &tty_fops);
3680 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3681 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3682 panic("Couldn't register /dev/tty driver\n");
3683 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3685 cdev_init(&console_cdev, &console_fops);
3686 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3687 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3688 panic("Couldn't register /dev/console driver\n");
3689 consdev = device_create_with_groups(tty_class, NULL,
3690 MKDEV(TTYAUX_MAJOR, 1), NULL,
3691 cons_dev_groups, "console");
3692 if (IS_ERR(consdev))
3696 vty_init(&console_fops);