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,
129 EXPORT_SYMBOL(tty_std_termios);
131 /* This list gets poked at by procfs and various bits of boot up code. This
132 could do with some rationalisation such as pulling the tty proc function
135 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
137 /* Mutex to protect creating and releasing a tty. This is shared with
138 vt.c for deeply disgusting hack reasons */
139 DEFINE_MUTEX(tty_mutex);
140 EXPORT_SYMBOL(tty_mutex);
142 /* Spinlock to protect the tty->tty_files list */
143 DEFINE_SPINLOCK(tty_files_lock);
145 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
146 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
147 ssize_t redirected_tty_write(struct file *, const char __user *,
149 static unsigned int tty_poll(struct file *, poll_table *);
150 static int tty_open(struct inode *, struct file *);
151 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
153 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
156 #define tty_compat_ioctl NULL
158 static int __tty_fasync(int fd, struct file *filp, int on);
159 static int tty_fasync(int fd, struct file *filp, int on);
160 static void release_tty(struct tty_struct *tty, int idx);
163 * free_tty_struct - free a disused tty
164 * @tty: tty struct to free
166 * Free the write buffers, tty queue and tty memory itself.
168 * Locking: none. Must be called after tty is definitely unused
171 static void free_tty_struct(struct tty_struct *tty)
173 tty_ldisc_deinit(tty);
174 put_device(tty->dev);
175 kfree(tty->write_buf);
176 tty->magic = 0xDEADDEAD;
180 static inline struct tty_struct *file_tty(struct file *file)
182 return ((struct tty_file_private *)file->private_data)->tty;
185 int tty_alloc_file(struct file *file)
187 struct tty_file_private *priv;
189 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
193 file->private_data = priv;
198 /* Associate a new file with the tty structure */
199 void tty_add_file(struct tty_struct *tty, struct file *file)
201 struct tty_file_private *priv = file->private_data;
206 spin_lock(&tty_files_lock);
207 list_add(&priv->list, &tty->tty_files);
208 spin_unlock(&tty_files_lock);
212 * tty_free_file - free file->private_data
214 * This shall be used only for fail path handling when tty_add_file was not
217 void tty_free_file(struct file *file)
219 struct tty_file_private *priv = file->private_data;
221 file->private_data = NULL;
225 /* Delete file from its tty */
226 static void tty_del_file(struct file *file)
228 struct tty_file_private *priv = file->private_data;
230 spin_lock(&tty_files_lock);
231 list_del(&priv->list);
232 spin_unlock(&tty_files_lock);
237 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
240 * tty_name - return tty naming
241 * @tty: tty structure
243 * Convert a tty structure into a name. The name reflects the kernel
244 * naming policy and if udev is in use may not reflect user space
249 const char *tty_name(const struct tty_struct *tty)
251 if (!tty) /* Hmm. NULL pointer. That's fun. */
256 EXPORT_SYMBOL(tty_name);
258 const char *tty_driver_name(const struct tty_struct *tty)
260 if (!tty || !tty->driver)
262 return tty->driver->name;
265 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
268 #ifdef TTY_PARANOIA_CHECK
270 pr_warn("(%d:%d): %s: NULL tty\n",
271 imajor(inode), iminor(inode), routine);
274 if (tty->magic != TTY_MAGIC) {
275 pr_warn("(%d:%d): %s: bad magic number\n",
276 imajor(inode), iminor(inode), routine);
283 /* Caller must hold tty_lock */
284 static int check_tty_count(struct tty_struct *tty, const char *routine)
286 #ifdef CHECK_TTY_COUNT
290 spin_lock(&tty_files_lock);
291 list_for_each(p, &tty->tty_files) {
294 spin_unlock(&tty_files_lock);
295 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
296 tty->driver->subtype == PTY_TYPE_SLAVE &&
297 tty->link && tty->link->count)
299 if (tty->count != count) {
300 tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
301 routine, tty->count, count);
309 * get_tty_driver - find device of a tty
310 * @dev_t: device identifier
311 * @index: returns the index of the tty
313 * This routine returns a tty driver structure, given a device number
314 * and also passes back the index number.
316 * Locking: caller must hold tty_mutex
319 static struct tty_driver *get_tty_driver(dev_t device, int *index)
321 struct tty_driver *p;
323 list_for_each_entry(p, &tty_drivers, tty_drivers) {
324 dev_t base = MKDEV(p->major, p->minor_start);
325 if (device < base || device >= base + p->num)
327 *index = device - base;
328 return tty_driver_kref_get(p);
333 #ifdef CONFIG_CONSOLE_POLL
336 * tty_find_polling_driver - find device of a polled tty
337 * @name: name string to match
338 * @line: pointer to resulting tty line nr
340 * This routine returns a tty driver structure, given a name
341 * and the condition that the tty driver is capable of polled
344 struct tty_driver *tty_find_polling_driver(char *name, int *line)
346 struct tty_driver *p, *res = NULL;
351 for (str = name; *str; str++)
352 if ((*str >= '0' && *str <= '9') || *str == ',')
358 tty_line = simple_strtoul(str, &str, 10);
360 mutex_lock(&tty_mutex);
361 /* Search through the tty devices to look for a match */
362 list_for_each_entry(p, &tty_drivers, tty_drivers) {
363 if (strncmp(name, p->name, len) != 0)
371 if (tty_line >= 0 && tty_line < p->num && p->ops &&
372 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
373 res = tty_driver_kref_get(p);
378 mutex_unlock(&tty_mutex);
382 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
386 * tty_check_change - check for POSIX terminal changes
389 * If we try to write to, or set the state of, a terminal and we're
390 * not in the foreground, send a SIGTTOU. If the signal is blocked or
391 * ignored, go ahead and perform the operation. (POSIX 7.2)
396 int __tty_check_change(struct tty_struct *tty, int sig)
399 struct pid *pgrp, *tty_pgrp;
402 if (current->signal->tty != tty)
406 pgrp = task_pgrp(current);
408 spin_lock_irqsave(&tty->ctrl_lock, flags);
409 tty_pgrp = tty->pgrp;
410 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
412 if (tty_pgrp && pgrp != tty->pgrp) {
413 if (is_ignored(sig)) {
416 } else if (is_current_pgrp_orphaned())
419 kill_pgrp(pgrp, sig, 1);
420 set_thread_flag(TIF_SIGPENDING);
427 tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);
432 int tty_check_change(struct tty_struct *tty)
434 return __tty_check_change(tty, SIGTTOU);
436 EXPORT_SYMBOL(tty_check_change);
438 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
439 size_t count, loff_t *ppos)
444 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
445 size_t count, loff_t *ppos)
450 /* No kernel lock held - none needed ;) */
451 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
453 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
456 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
459 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
462 static long hung_up_tty_compat_ioctl(struct file *file,
463 unsigned int cmd, unsigned long arg)
465 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
468 static const struct file_operations tty_fops = {
473 .unlocked_ioctl = tty_ioctl,
474 .compat_ioctl = tty_compat_ioctl,
476 .release = tty_release,
477 .fasync = tty_fasync,
480 static const struct file_operations console_fops = {
483 .write = redirected_tty_write,
485 .unlocked_ioctl = tty_ioctl,
486 .compat_ioctl = tty_compat_ioctl,
488 .release = tty_release,
489 .fasync = tty_fasync,
492 static const struct file_operations hung_up_tty_fops = {
494 .read = hung_up_tty_read,
495 .write = hung_up_tty_write,
496 .poll = hung_up_tty_poll,
497 .unlocked_ioctl = hung_up_tty_ioctl,
498 .compat_ioctl = hung_up_tty_compat_ioctl,
499 .release = tty_release,
502 static DEFINE_SPINLOCK(redirect_lock);
503 static struct file *redirect;
506 void proc_clear_tty(struct task_struct *p)
509 struct tty_struct *tty;
510 spin_lock_irqsave(&p->sighand->siglock, flags);
511 tty = p->signal->tty;
512 p->signal->tty = NULL;
513 spin_unlock_irqrestore(&p->sighand->siglock, flags);
518 * proc_set_tty - set the controlling terminal
520 * Only callable by the session leader and only if it does not already have
521 * a controlling terminal.
523 * Caller must hold: tty_lock()
524 * a readlock on tasklist_lock
527 static void __proc_set_tty(struct tty_struct *tty)
531 spin_lock_irqsave(&tty->ctrl_lock, flags);
533 * The session and fg pgrp references will be non-NULL if
534 * tiocsctty() is stealing the controlling tty
536 put_pid(tty->session);
538 tty->pgrp = get_pid(task_pgrp(current));
539 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
540 tty->session = get_pid(task_session(current));
541 if (current->signal->tty) {
542 tty_debug(tty, "current tty %s not NULL!!\n",
543 current->signal->tty->name);
544 tty_kref_put(current->signal->tty);
546 put_pid(current->signal->tty_old_pgrp);
547 current->signal->tty = tty_kref_get(tty);
548 current->signal->tty_old_pgrp = NULL;
551 static void proc_set_tty(struct tty_struct *tty)
553 spin_lock_irq(¤t->sighand->siglock);
555 spin_unlock_irq(¤t->sighand->siglock);
558 struct tty_struct *get_current_tty(void)
560 struct tty_struct *tty;
563 spin_lock_irqsave(¤t->sighand->siglock, flags);
564 tty = tty_kref_get(current->signal->tty);
565 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
568 EXPORT_SYMBOL_GPL(get_current_tty);
570 static void session_clear_tty(struct pid *session)
572 struct task_struct *p;
573 do_each_pid_task(session, PIDTYPE_SID, p) {
575 } while_each_pid_task(session, PIDTYPE_SID, p);
579 * tty_wakeup - request more data
582 * Internal and external helper for wakeups of tty. This function
583 * informs the line discipline if present that the driver is ready
584 * to receive more output data.
587 void tty_wakeup(struct tty_struct *tty)
589 struct tty_ldisc *ld;
591 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
592 ld = tty_ldisc_ref(tty);
594 if (ld->ops->write_wakeup)
595 ld->ops->write_wakeup(tty);
599 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
602 EXPORT_SYMBOL_GPL(tty_wakeup);
605 * tty_signal_session_leader - sends SIGHUP to session leader
606 * @tty controlling tty
607 * @exit_session if non-zero, signal all foreground group processes
609 * Send SIGHUP and SIGCONT to the session leader and its process group.
610 * Optionally, signal all processes in the foreground process group.
612 * Returns the number of processes in the session with this tty
613 * as their controlling terminal. This value is used to drop
614 * tty references for those processes.
616 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
618 struct task_struct *p;
620 struct pid *tty_pgrp = NULL;
622 read_lock(&tasklist_lock);
624 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
625 spin_lock_irq(&p->sighand->siglock);
626 if (p->signal->tty == tty) {
627 p->signal->tty = NULL;
628 /* We defer the dereferences outside fo
632 if (!p->signal->leader) {
633 spin_unlock_irq(&p->sighand->siglock);
636 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
637 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
638 put_pid(p->signal->tty_old_pgrp); /* A noop */
639 spin_lock(&tty->ctrl_lock);
640 tty_pgrp = get_pid(tty->pgrp);
642 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
643 spin_unlock(&tty->ctrl_lock);
644 spin_unlock_irq(&p->sighand->siglock);
645 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
647 read_unlock(&tasklist_lock);
651 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
659 * __tty_hangup - actual handler for hangup events
662 * This can be called by a "kworker" kernel thread. That is process
663 * synchronous but doesn't hold any locks, so we need to make sure we
664 * have the appropriate locks for what we're doing.
666 * The hangup event clears any pending redirections onto the hung up
667 * device. It ensures future writes will error and it does the needed
668 * line discipline hangup and signal delivery. The tty object itself
673 * redirect lock for undoing redirection
674 * file list lock for manipulating list of ttys
675 * tty_ldiscs_lock from called functions
676 * termios_rwsem resetting termios data
677 * tasklist_lock to walk task list for hangup event
678 * ->siglock to protect ->signal/->sighand
680 static void __tty_hangup(struct tty_struct *tty, int exit_session)
682 struct file *cons_filp = NULL;
683 struct file *filp, *f = NULL;
684 struct tty_file_private *priv;
685 int closecount = 0, n;
692 spin_lock(&redirect_lock);
693 if (redirect && file_tty(redirect) == tty) {
697 spin_unlock(&redirect_lock);
701 if (test_bit(TTY_HUPPED, &tty->flags)) {
706 /* inuse_filps is protected by the single tty lock,
707 this really needs to change if we want to flush the
708 workqueue with the lock held */
709 check_tty_count(tty, "tty_hangup");
711 spin_lock(&tty_files_lock);
712 /* This breaks for file handles being sent over AF_UNIX sockets ? */
713 list_for_each_entry(priv, &tty->tty_files, list) {
715 if (filp->f_op->write == redirected_tty_write)
717 if (filp->f_op->write != tty_write)
720 __tty_fasync(-1, filp, 0); /* can't block */
721 filp->f_op = &hung_up_tty_fops;
723 spin_unlock(&tty_files_lock);
725 refs = tty_signal_session_leader(tty, exit_session);
726 /* Account for the p->signal references we killed */
730 tty_ldisc_hangup(tty);
732 spin_lock_irq(&tty->ctrl_lock);
733 clear_bit(TTY_THROTTLED, &tty->flags);
734 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
735 put_pid(tty->session);
739 tty->ctrl_status = 0;
740 spin_unlock_irq(&tty->ctrl_lock);
743 * If one of the devices matches a console pointer, we
744 * cannot just call hangup() because that will cause
745 * tty->count and state->count to go out of sync.
746 * So we just call close() the right number of times.
750 for (n = 0; n < closecount; n++)
751 tty->ops->close(tty, cons_filp);
752 } else if (tty->ops->hangup)
753 tty->ops->hangup(tty);
755 * We don't want to have driver/ldisc interactions beyond
756 * the ones we did here. The driver layer expects no
757 * calls after ->hangup() from the ldisc side. However we
758 * can't yet guarantee all that.
760 set_bit(TTY_HUPPED, &tty->flags);
767 static void do_tty_hangup(struct work_struct *work)
769 struct tty_struct *tty =
770 container_of(work, struct tty_struct, hangup_work);
772 __tty_hangup(tty, 0);
776 * tty_hangup - trigger a hangup event
777 * @tty: tty to hangup
779 * A carrier loss (virtual or otherwise) has occurred on this like
780 * schedule a hangup sequence to run after this event.
783 void tty_hangup(struct tty_struct *tty)
785 tty_debug_hangup(tty, "hangup\n");
786 schedule_work(&tty->hangup_work);
789 EXPORT_SYMBOL(tty_hangup);
792 * tty_vhangup - process vhangup
793 * @tty: tty to hangup
795 * The user has asked via system call for the terminal to be hung up.
796 * We do this synchronously so that when the syscall returns the process
797 * is complete. That guarantee is necessary for security reasons.
800 void tty_vhangup(struct tty_struct *tty)
802 tty_debug_hangup(tty, "vhangup\n");
803 __tty_hangup(tty, 0);
806 EXPORT_SYMBOL(tty_vhangup);
810 * tty_vhangup_self - process vhangup for own ctty
812 * Perform a vhangup on the current controlling tty
815 void tty_vhangup_self(void)
817 struct tty_struct *tty;
819 tty = get_current_tty();
827 * tty_vhangup_session - hangup session leader exit
828 * @tty: tty to hangup
830 * The session leader is exiting and hanging up its controlling terminal.
831 * Every process in the foreground process group is signalled SIGHUP.
833 * We do this synchronously so that when the syscall returns the process
834 * is complete. That guarantee is necessary for security reasons.
837 static void tty_vhangup_session(struct tty_struct *tty)
839 tty_debug_hangup(tty, "session hangup\n");
840 __tty_hangup(tty, 1);
844 * tty_hung_up_p - was tty hung up
845 * @filp: file pointer of tty
847 * Return true if the tty has been subject to a vhangup or a carrier
851 int tty_hung_up_p(struct file *filp)
853 return (filp->f_op == &hung_up_tty_fops);
856 EXPORT_SYMBOL(tty_hung_up_p);
859 * disassociate_ctty - disconnect controlling tty
860 * @on_exit: true if exiting so need to "hang up" the session
862 * This function is typically called only by the session leader, when
863 * it wants to disassociate itself from its controlling tty.
865 * It performs the following functions:
866 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
867 * (2) Clears the tty from being controlling the session
868 * (3) Clears the controlling tty for all processes in the
871 * The argument on_exit is set to 1 if called when a process is
872 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
875 * BTM is taken for hysterical raisins, and held when
876 * called from no_tty().
877 * tty_mutex is taken to protect tty
878 * ->siglock is taken to protect ->signal/->sighand
879 * tasklist_lock is taken to walk process list for sessions
880 * ->siglock is taken to protect ->signal/->sighand
883 void disassociate_ctty(int on_exit)
885 struct tty_struct *tty;
887 if (!current->signal->leader)
890 tty = get_current_tty();
892 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
893 tty_vhangup_session(tty);
895 struct pid *tty_pgrp = tty_get_pgrp(tty);
897 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
899 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
905 } else if (on_exit) {
906 struct pid *old_pgrp;
907 spin_lock_irq(¤t->sighand->siglock);
908 old_pgrp = current->signal->tty_old_pgrp;
909 current->signal->tty_old_pgrp = NULL;
910 spin_unlock_irq(¤t->sighand->siglock);
912 kill_pgrp(old_pgrp, SIGHUP, on_exit);
913 kill_pgrp(old_pgrp, SIGCONT, on_exit);
919 spin_lock_irq(¤t->sighand->siglock);
920 put_pid(current->signal->tty_old_pgrp);
921 current->signal->tty_old_pgrp = NULL;
923 tty = tty_kref_get(current->signal->tty);
926 spin_lock_irqsave(&tty->ctrl_lock, flags);
927 put_pid(tty->session);
931 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
934 tty_debug_hangup(tty, "no current tty\n");
936 spin_unlock_irq(¤t->sighand->siglock);
937 /* Now clear signal->tty under the lock */
938 read_lock(&tasklist_lock);
939 session_clear_tty(task_session(current));
940 read_unlock(&tasklist_lock);
945 * no_tty - Ensure the current process does not have a controlling tty
949 /* FIXME: Review locking here. The tty_lock never covered any race
950 between a new association and proc_clear_tty but possible we need
951 to protect against this anyway */
952 struct task_struct *tsk = current;
953 disassociate_ctty(0);
959 * stop_tty - propagate flow control
962 * Perform flow control to the driver. May be called
963 * on an already stopped device and will not re-call the driver
966 * This functionality is used by both the line disciplines for
967 * halting incoming flow and by the driver. It may therefore be
968 * called from any context, may be under the tty atomic_write_lock
975 void __stop_tty(struct tty_struct *tty)
984 void stop_tty(struct tty_struct *tty)
988 spin_lock_irqsave(&tty->flow_lock, flags);
990 spin_unlock_irqrestore(&tty->flow_lock, flags);
992 EXPORT_SYMBOL(stop_tty);
995 * start_tty - propagate flow control
998 * Start a tty that has been stopped if at all possible. If this
999 * tty was previous stopped and is now being started, the driver
1000 * start method is invoked and the line discipline woken.
1006 void __start_tty(struct tty_struct *tty)
1008 if (!tty->stopped || tty->flow_stopped)
1011 if (tty->ops->start)
1012 tty->ops->start(tty);
1016 void start_tty(struct tty_struct *tty)
1018 unsigned long flags;
1020 spin_lock_irqsave(&tty->flow_lock, flags);
1022 spin_unlock_irqrestore(&tty->flow_lock, flags);
1024 EXPORT_SYMBOL(start_tty);
1026 static void tty_update_time(struct timespec *time)
1028 unsigned long sec = get_seconds();
1031 * We only care if the two values differ in anything other than the
1032 * lower three bits (i.e every 8 seconds). If so, then we can update
1033 * the time of the tty device, otherwise it could be construded as a
1034 * security leak to let userspace know the exact timing of the tty.
1036 if ((sec ^ time->tv_sec) & ~7)
1041 * tty_read - read method for tty device files
1042 * @file: pointer to tty file
1044 * @count: size of user buffer
1047 * Perform the read system call function on this terminal device. Checks
1048 * for hung up devices before calling the line discipline method.
1051 * Locks the line discipline internally while needed. Multiple
1052 * read calls may be outstanding in parallel.
1055 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1059 struct inode *inode = file_inode(file);
1060 struct tty_struct *tty = file_tty(file);
1061 struct tty_ldisc *ld;
1063 if (tty_paranoia_check(tty, inode, "tty_read"))
1065 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1068 /* We want to wait for the line discipline to sort out in this
1070 ld = tty_ldisc_ref_wait(tty);
1072 i = ld->ops->read(tty, file, buf, count);
1075 tty_ldisc_deref(ld);
1078 tty_update_time(&inode->i_atime);
1083 static void tty_write_unlock(struct tty_struct *tty)
1085 mutex_unlock(&tty->atomic_write_lock);
1086 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1089 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1091 if (!mutex_trylock(&tty->atomic_write_lock)) {
1094 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1095 return -ERESTARTSYS;
1101 * Split writes up in sane blocksizes to avoid
1102 * denial-of-service type attacks
1104 static inline ssize_t do_tty_write(
1105 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1106 struct tty_struct *tty,
1108 const char __user *buf,
1111 ssize_t ret, written = 0;
1114 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1119 * We chunk up writes into a temporary buffer. This
1120 * simplifies low-level drivers immensely, since they
1121 * don't have locking issues and user mode accesses.
1123 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1126 * The default chunk-size is 2kB, because the NTTY
1127 * layer has problems with bigger chunks. It will
1128 * claim to be able to handle more characters than
1131 * FIXME: This can probably go away now except that 64K chunks
1132 * are too likely to fail unless switched to vmalloc...
1135 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1140 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1141 if (tty->write_cnt < chunk) {
1142 unsigned char *buf_chunk;
1147 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1152 kfree(tty->write_buf);
1153 tty->write_cnt = chunk;
1154 tty->write_buf = buf_chunk;
1157 /* Do the write .. */
1159 size_t size = count;
1163 if (copy_from_user(tty->write_buf, buf, size))
1165 ret = write(tty, file, tty->write_buf, size);
1174 if (signal_pending(current))
1179 tty_update_time(&file_inode(file)->i_mtime);
1183 tty_write_unlock(tty);
1188 * tty_write_message - write a message to a certain tty, not just the console.
1189 * @tty: the destination tty_struct
1190 * @msg: the message to write
1192 * This is used for messages that need to be redirected to a specific tty.
1193 * We don't put it into the syslog queue right now maybe in the future if
1196 * We must still hold the BTM and test the CLOSING flag for the moment.
1199 void tty_write_message(struct tty_struct *tty, char *msg)
1202 mutex_lock(&tty->atomic_write_lock);
1204 if (tty->ops->write && tty->count > 0)
1205 tty->ops->write(tty, msg, strlen(msg));
1207 tty_write_unlock(tty);
1214 * tty_write - write method for tty device file
1215 * @file: tty file pointer
1216 * @buf: user data to write
1217 * @count: bytes to write
1220 * Write data to a tty device via the line discipline.
1223 * Locks the line discipline as required
1224 * Writes to the tty driver are serialized by the atomic_write_lock
1225 * and are then processed in chunks to the device. The line discipline
1226 * write method will not be invoked in parallel for each device.
1229 static ssize_t tty_write(struct file *file, const char __user *buf,
1230 size_t count, loff_t *ppos)
1232 struct tty_struct *tty = file_tty(file);
1233 struct tty_ldisc *ld;
1236 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1238 if (!tty || !tty->ops->write ||
1239 (test_bit(TTY_IO_ERROR, &tty->flags)))
1241 /* Short term debug to catch buggy drivers */
1242 if (tty->ops->write_room == NULL)
1243 tty_err(tty, "missing write_room method\n");
1244 ld = tty_ldisc_ref_wait(tty);
1245 if (!ld->ops->write)
1248 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1249 tty_ldisc_deref(ld);
1253 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1254 size_t count, loff_t *ppos)
1256 struct file *p = NULL;
1258 spin_lock(&redirect_lock);
1260 p = get_file(redirect);
1261 spin_unlock(&redirect_lock);
1265 res = vfs_write(p, buf, count, &p->f_pos);
1269 return tty_write(file, buf, count, ppos);
1273 * tty_send_xchar - send priority character
1275 * Send a high priority character to the tty even if stopped
1277 * Locking: none for xchar method, write ordering for write method.
1280 int tty_send_xchar(struct tty_struct *tty, char ch)
1282 int was_stopped = tty->stopped;
1284 if (tty->ops->send_xchar) {
1285 down_read(&tty->termios_rwsem);
1286 tty->ops->send_xchar(tty, ch);
1287 up_read(&tty->termios_rwsem);
1291 if (tty_write_lock(tty, 0) < 0)
1292 return -ERESTARTSYS;
1294 down_read(&tty->termios_rwsem);
1297 tty->ops->write(tty, &ch, 1);
1300 up_read(&tty->termios_rwsem);
1301 tty_write_unlock(tty);
1305 static char ptychar[] = "pqrstuvwxyzabcde";
1308 * pty_line_name - generate name for a pty
1309 * @driver: the tty driver in use
1310 * @index: the minor number
1311 * @p: output buffer of at least 6 bytes
1313 * Generate a name from a driver reference and write it to the output
1318 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1320 int i = index + driver->name_base;
1321 /* ->name is initialized to "ttyp", but "tty" is expected */
1322 sprintf(p, "%s%c%x",
1323 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1324 ptychar[i >> 4 & 0xf], i & 0xf);
1328 * tty_line_name - generate name for a tty
1329 * @driver: the tty driver in use
1330 * @index: the minor number
1331 * @p: output buffer of at least 7 bytes
1333 * Generate a name from a driver reference and write it to the output
1338 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1340 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1341 return sprintf(p, "%s", driver->name);
1343 return sprintf(p, "%s%d", driver->name,
1344 index + driver->name_base);
1348 * tty_driver_lookup_tty() - find an existing tty, if any
1349 * @driver: the driver for the tty
1350 * @idx: the minor number
1352 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1353 * driver lookup() method returns an error.
1355 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1357 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1358 struct inode *inode, int idx)
1360 struct tty_struct *tty;
1362 if (driver->ops->lookup)
1363 tty = driver->ops->lookup(driver, inode, idx);
1365 tty = driver->ttys[idx];
1373 * tty_init_termios - helper for termios setup
1374 * @tty: the tty to set up
1376 * Initialise the termios structures for this tty. Thus runs under
1377 * the tty_mutex currently so we can be relaxed about ordering.
1380 void tty_init_termios(struct tty_struct *tty)
1382 struct ktermios *tp;
1383 int idx = tty->index;
1385 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1386 tty->termios = tty->driver->init_termios;
1388 /* Check for lazy saved data */
1389 tp = tty->driver->termios[idx];
1392 tty->termios.c_line = tty->driver->init_termios.c_line;
1394 tty->termios = tty->driver->init_termios;
1396 /* Compatibility until drivers always set this */
1397 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1398 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1400 EXPORT_SYMBOL_GPL(tty_init_termios);
1402 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1404 tty_init_termios(tty);
1405 tty_driver_kref_get(driver);
1407 driver->ttys[tty->index] = tty;
1410 EXPORT_SYMBOL_GPL(tty_standard_install);
1413 * tty_driver_install_tty() - install a tty entry in the driver
1414 * @driver: the driver for the tty
1417 * Install a tty object into the driver tables. The tty->index field
1418 * will be set by the time this is called. This method is responsible
1419 * for ensuring any need additional structures are allocated and
1422 * Locking: tty_mutex for now
1424 static int tty_driver_install_tty(struct tty_driver *driver,
1425 struct tty_struct *tty)
1427 return driver->ops->install ? driver->ops->install(driver, tty) :
1428 tty_standard_install(driver, tty);
1432 * tty_driver_remove_tty() - remove a tty from the driver tables
1433 * @driver: the driver for the tty
1434 * @idx: the minor number
1436 * Remvoe a tty object from the driver tables. The tty->index field
1437 * will be set by the time this is called.
1439 * Locking: tty_mutex for now
1441 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1443 if (driver->ops->remove)
1444 driver->ops->remove(driver, tty);
1446 driver->ttys[tty->index] = NULL;
1450 * tty_reopen() - fast re-open of an open tty
1451 * @tty - the tty to open
1453 * Return 0 on success, -errno on error.
1454 * Re-opens on master ptys are not allowed and return -EIO.
1456 * Locking: Caller must hold tty_lock
1458 static int tty_reopen(struct tty_struct *tty)
1460 struct tty_driver *driver = tty->driver;
1462 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1463 driver->subtype == PTY_TYPE_MASTER)
1469 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1474 WARN_ON(!tty->ldisc);
1480 * tty_init_dev - initialise a tty device
1481 * @driver: tty driver we are opening a device on
1482 * @idx: device index
1483 * @ret_tty: returned tty structure
1485 * Prepare a tty device. This may not be a "new" clean device but
1486 * could also be an active device. The pty drivers require special
1487 * handling because of this.
1490 * The function is called under the tty_mutex, which
1491 * protects us from the tty struct or driver itself going away.
1493 * On exit the tty device has the line discipline attached and
1494 * a reference count of 1. If a pair was created for pty/tty use
1495 * and the other was a pty master then it too has a reference count of 1.
1497 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1498 * failed open. The new code protects the open with a mutex, so it's
1499 * really quite straightforward. The mutex locking can probably be
1500 * relaxed for the (most common) case of reopening a tty.
1503 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1505 struct tty_struct *tty;
1509 * First time open is complex, especially for PTY devices.
1510 * This code guarantees that either everything succeeds and the
1511 * TTY is ready for operation, or else the table slots are vacated
1512 * and the allocated memory released. (Except that the termios
1513 * and locked termios may be retained.)
1516 if (!try_module_get(driver->owner))
1517 return ERR_PTR(-ENODEV);
1519 tty = alloc_tty_struct(driver, idx);
1522 goto err_module_put;
1526 retval = tty_driver_install_tty(driver, tty);
1531 tty->port = driver->ports[idx];
1533 WARN_RATELIMIT(!tty->port,
1534 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1535 __func__, tty->driver->name);
1537 tty->port->itty = tty;
1540 * Structures all installed ... call the ldisc open routines.
1541 * If we fail here just call release_tty to clean up. No need
1542 * to decrement the use counts, as release_tty doesn't care.
1544 retval = tty_ldisc_setup(tty, tty->link);
1546 goto err_release_tty;
1547 /* Return the tty locked so that it cannot vanish under the caller */
1552 free_tty_struct(tty);
1554 module_put(driver->owner);
1555 return ERR_PTR(retval);
1557 /* call the tty release_tty routine to clean out this slot */
1560 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1562 release_tty(tty, idx);
1563 return ERR_PTR(retval);
1566 static void tty_free_termios(struct tty_struct *tty)
1568 struct ktermios *tp;
1569 int idx = tty->index;
1571 /* If the port is going to reset then it has no termios to save */
1572 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1575 /* Stash the termios data */
1576 tp = tty->driver->termios[idx];
1578 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1581 tty->driver->termios[idx] = tp;
1587 * tty_flush_works - flush all works of a tty/pty pair
1588 * @tty: tty device to flush works for (or either end of a pty pair)
1590 * Sync flush all works belonging to @tty (and the 'other' tty).
1592 static void tty_flush_works(struct tty_struct *tty)
1594 flush_work(&tty->SAK_work);
1595 flush_work(&tty->hangup_work);
1597 flush_work(&tty->link->SAK_work);
1598 flush_work(&tty->link->hangup_work);
1603 * release_one_tty - release tty structure memory
1604 * @kref: kref of tty we are obliterating
1606 * Releases memory associated with a tty structure, and clears out the
1607 * driver table slots. This function is called when a device is no longer
1608 * in use. It also gets called when setup of a device fails.
1611 * takes the file list lock internally when working on the list
1612 * of ttys that the driver keeps.
1614 * This method gets called from a work queue so that the driver private
1615 * cleanup ops can sleep (needed for USB at least)
1617 static void release_one_tty(struct work_struct *work)
1619 struct tty_struct *tty =
1620 container_of(work, struct tty_struct, hangup_work);
1621 struct tty_driver *driver = tty->driver;
1622 struct module *owner = driver->owner;
1624 if (tty->ops->cleanup)
1625 tty->ops->cleanup(tty);
1628 tty_driver_kref_put(driver);
1631 spin_lock(&tty_files_lock);
1632 list_del_init(&tty->tty_files);
1633 spin_unlock(&tty_files_lock);
1636 put_pid(tty->session);
1637 free_tty_struct(tty);
1640 static void queue_release_one_tty(struct kref *kref)
1642 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1644 /* The hangup queue is now free so we can reuse it rather than
1645 waste a chunk of memory for each port */
1646 INIT_WORK(&tty->hangup_work, release_one_tty);
1647 schedule_work(&tty->hangup_work);
1651 * tty_kref_put - release a tty kref
1654 * Release a reference to a tty device and if need be let the kref
1655 * layer destruct the object for us
1658 void tty_kref_put(struct tty_struct *tty)
1661 kref_put(&tty->kref, queue_release_one_tty);
1663 EXPORT_SYMBOL(tty_kref_put);
1666 * release_tty - release tty structure memory
1668 * Release both @tty and a possible linked partner (think pty pair),
1669 * and decrement the refcount of the backing module.
1673 * takes the file list lock internally when working on the list
1674 * of ttys that the driver keeps.
1677 static void release_tty(struct tty_struct *tty, int idx)
1679 /* This should always be true but check for the moment */
1680 WARN_ON(tty->index != idx);
1681 WARN_ON(!mutex_is_locked(&tty_mutex));
1682 if (tty->ops->shutdown)
1683 tty->ops->shutdown(tty);
1684 tty_free_termios(tty);
1685 tty_driver_remove_tty(tty->driver, tty);
1686 tty->port->itty = NULL;
1688 tty->link->port->itty = NULL;
1689 tty_buffer_cancel_work(tty->port);
1691 tty_kref_put(tty->link);
1696 * tty_release_checks - check a tty before real release
1697 * @tty: tty to check
1698 * @o_tty: link of @tty (if any)
1699 * @idx: index of the tty
1701 * Performs some paranoid checking before true release of the @tty.
1702 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1704 static int tty_release_checks(struct tty_struct *tty, int idx)
1706 #ifdef TTY_PARANOIA_CHECK
1707 if (idx < 0 || idx >= tty->driver->num) {
1708 tty_debug(tty, "bad idx %d\n", idx);
1712 /* not much to check for devpts */
1713 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1716 if (tty != tty->driver->ttys[idx]) {
1717 tty_debug(tty, "bad driver table[%d] = %p\n",
1718 idx, tty->driver->ttys[idx]);
1721 if (tty->driver->other) {
1722 struct tty_struct *o_tty = tty->link;
1724 if (o_tty != tty->driver->other->ttys[idx]) {
1725 tty_debug(tty, "bad other table[%d] = %p\n",
1726 idx, tty->driver->other->ttys[idx]);
1729 if (o_tty->link != tty) {
1730 tty_debug(tty, "bad link = %p\n", o_tty->link);
1739 * tty_release - vfs callback for close
1740 * @inode: inode of tty
1741 * @filp: file pointer for handle to tty
1743 * Called the last time each file handle is closed that references
1744 * this tty. There may however be several such references.
1747 * Takes bkl. See tty_release_dev
1749 * Even releasing the tty structures is a tricky business.. We have
1750 * to be very careful that the structures are all released at the
1751 * same time, as interrupts might otherwise get the wrong pointers.
1753 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1754 * lead to double frees or releasing memory still in use.
1757 int tty_release(struct inode *inode, struct file *filp)
1759 struct tty_struct *tty = file_tty(filp);
1760 struct tty_struct *o_tty = NULL;
1761 int do_sleep, final;
1766 if (tty_paranoia_check(tty, inode, __func__))
1770 check_tty_count(tty, __func__);
1772 __tty_fasync(-1, filp, 0);
1775 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1776 tty->driver->subtype == PTY_TYPE_MASTER)
1779 if (tty_release_checks(tty, idx)) {
1784 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1786 if (tty->ops->close)
1787 tty->ops->close(tty, filp);
1789 /* If tty is pty master, lock the slave pty (stable lock order) */
1790 tty_lock_slave(o_tty);
1793 * Sanity check: if tty->count is going to zero, there shouldn't be
1794 * any waiters on tty->read_wait or tty->write_wait. We test the
1795 * wait queues and kick everyone out _before_ actually starting to
1796 * close. This ensures that we won't block while releasing the tty
1799 * The test for the o_tty closing is necessary, since the master and
1800 * slave sides may close in any order. If the slave side closes out
1801 * first, its count will be one, since the master side holds an open.
1802 * Thus this test wouldn't be triggered at the time the slave closed,
1808 if (tty->count <= 1) {
1809 if (waitqueue_active(&tty->read_wait)) {
1810 wake_up_poll(&tty->read_wait, POLLIN);
1813 if (waitqueue_active(&tty->write_wait)) {
1814 wake_up_poll(&tty->write_wait, POLLOUT);
1818 if (o_tty && o_tty->count <= 1) {
1819 if (waitqueue_active(&o_tty->read_wait)) {
1820 wake_up_poll(&o_tty->read_wait, POLLIN);
1823 if (waitqueue_active(&o_tty->write_wait)) {
1824 wake_up_poll(&o_tty->write_wait, POLLOUT);
1833 tty_warn(tty, "read/write wait queue active!\n");
1835 schedule_timeout_killable(timeout);
1836 if (timeout < 120 * HZ)
1837 timeout = 2 * timeout + 1;
1839 timeout = MAX_SCHEDULE_TIMEOUT;
1843 if (--o_tty->count < 0) {
1844 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1848 if (--tty->count < 0) {
1849 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1854 * We've decremented tty->count, so we need to remove this file
1855 * descriptor off the tty->tty_files list; this serves two
1857 * - check_tty_count sees the correct number of file descriptors
1858 * associated with this tty.
1859 * - do_tty_hangup no longer sees this file descriptor as
1860 * something that needs to be handled for hangups.
1865 * Perform some housekeeping before deciding whether to return.
1867 * If _either_ side is closing, make sure there aren't any
1868 * processes that still think tty or o_tty is their controlling
1872 read_lock(&tasklist_lock);
1873 session_clear_tty(tty->session);
1875 session_clear_tty(o_tty->session);
1876 read_unlock(&tasklist_lock);
1879 /* check whether both sides are closing ... */
1880 final = !tty->count && !(o_tty && o_tty->count);
1882 tty_unlock_slave(o_tty);
1885 /* At this point, the tty->count == 0 should ensure a dead tty
1886 cannot be re-opened by a racing opener */
1891 tty_debug_hangup(tty, "final close\n");
1893 * Ask the line discipline code to release its structures
1895 tty_ldisc_release(tty);
1897 /* Wait for pending work before tty destruction commmences */
1898 tty_flush_works(tty);
1900 tty_debug_hangup(tty, "freeing structure\n");
1902 * The release_tty function takes care of the details of clearing
1903 * the slots and preserving the termios structure. The tty_unlock_pair
1904 * should be safe as we keep a kref while the tty is locked (so the
1905 * unlock never unlocks a freed tty).
1907 mutex_lock(&tty_mutex);
1908 release_tty(tty, idx);
1909 mutex_unlock(&tty_mutex);
1915 * tty_open_current_tty - get locked tty of current task
1916 * @device: device number
1917 * @filp: file pointer to tty
1918 * @return: locked tty of the current task iff @device is /dev/tty
1920 * Performs a re-open of the current task's controlling tty.
1922 * We cannot return driver and index like for the other nodes because
1923 * devpts will not work then. It expects inodes to be from devpts FS.
1925 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1927 struct tty_struct *tty;
1930 if (device != MKDEV(TTYAUX_MAJOR, 0))
1933 tty = get_current_tty();
1935 return ERR_PTR(-ENXIO);
1937 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1940 tty_kref_put(tty); /* safe to drop the kref now */
1942 retval = tty_reopen(tty);
1945 tty = ERR_PTR(retval);
1951 * tty_lookup_driver - lookup a tty driver for a given device file
1952 * @device: device number
1953 * @filp: file pointer to tty
1954 * @noctty: set if the device should not become a controlling tty
1955 * @index: index for the device in the @return driver
1956 * @return: driver for this inode (with increased refcount)
1958 * If @return is not erroneous, the caller is responsible to decrement the
1959 * refcount by tty_driver_kref_put.
1961 * Locking: tty_mutex protects get_tty_driver
1963 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1966 struct tty_driver *driver;
1970 case MKDEV(TTY_MAJOR, 0): {
1971 extern struct tty_driver *console_driver;
1972 driver = tty_driver_kref_get(console_driver);
1973 *index = fg_console;
1977 case MKDEV(TTYAUX_MAJOR, 1): {
1978 struct tty_driver *console_driver = console_device(index);
1979 if (console_driver) {
1980 driver = tty_driver_kref_get(console_driver);
1982 /* Don't let /dev/console block */
1983 filp->f_flags |= O_NONBLOCK;
1987 return ERR_PTR(-ENODEV);
1990 driver = get_tty_driver(device, index);
1992 return ERR_PTR(-ENODEV);
1999 * tty_open_by_driver - open a tty device
2000 * @device: dev_t of device to open
2001 * @inode: inode of device file
2002 * @filp: file pointer to tty
2004 * Performs the driver lookup, checks for a reopen, or otherwise
2005 * performs the first-time tty initialization.
2007 * Returns the locked initialized or re-opened &tty_struct
2009 * Claims the global tty_mutex to serialize:
2010 * - concurrent first-time tty initialization
2011 * - concurrent tty driver removal w/ lookup
2012 * - concurrent tty removal from driver table
2014 static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
2017 struct tty_struct *tty;
2018 struct tty_driver *driver = NULL;
2022 mutex_lock(&tty_mutex);
2023 driver = tty_lookup_driver(device, filp, &index);
2024 if (IS_ERR(driver)) {
2025 mutex_unlock(&tty_mutex);
2026 return ERR_CAST(driver);
2029 /* check whether we're reopening an existing tty */
2030 tty = tty_driver_lookup_tty(driver, inode, index);
2032 mutex_unlock(&tty_mutex);
2037 mutex_unlock(&tty_mutex);
2038 retval = tty_lock_interruptible(tty);
2040 if (retval == -EINTR)
2041 retval = -ERESTARTSYS;
2042 tty = ERR_PTR(retval);
2045 /* safe to drop the kref from tty_driver_lookup_tty() */
2047 retval = tty_reopen(tty);
2050 tty = ERR_PTR(retval);
2052 } else { /* Returns with the tty_lock held for now */
2053 tty = tty_init_dev(driver, index);
2054 mutex_unlock(&tty_mutex);
2057 tty_driver_kref_put(driver);
2062 * tty_open - open a tty device
2063 * @inode: inode of device file
2064 * @filp: file pointer to tty
2066 * tty_open and tty_release keep up the tty count that contains the
2067 * number of opens done on a tty. We cannot use the inode-count, as
2068 * different inodes might point to the same tty.
2070 * Open-counting is needed for pty masters, as well as for keeping
2071 * track of serial lines: DTR is dropped when the last close happens.
2072 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2074 * The termios state of a pty is reset on first open so that
2075 * settings don't persist across reuse.
2077 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2078 * tty->count should protect the rest.
2079 * ->siglock protects ->signal/->sighand
2081 * Note: the tty_unlock/lock cases without a ref are only safe due to
2085 static int tty_open(struct inode *inode, struct file *filp)
2087 struct tty_struct *tty;
2089 dev_t device = inode->i_rdev;
2090 unsigned saved_flags = filp->f_flags;
2092 nonseekable_open(inode, filp);
2095 retval = tty_alloc_file(filp);
2099 tty = tty_open_current_tty(device, filp);
2101 tty = tty_open_by_driver(device, inode, filp);
2104 tty_free_file(filp);
2105 retval = PTR_ERR(tty);
2106 if (retval != -EAGAIN || signal_pending(current))
2112 tty_add_file(tty, filp);
2114 check_tty_count(tty, __func__);
2115 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2118 retval = tty->ops->open(tty, filp);
2121 filp->f_flags = saved_flags;
2124 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2126 tty_unlock(tty); /* need to call tty_release without BTM */
2127 tty_release(inode, filp);
2128 if (retval != -ERESTARTSYS)
2131 if (signal_pending(current))
2136 * Need to reset f_op in case a hangup happened.
2138 if (tty_hung_up_p(filp))
2139 filp->f_op = &tty_fops;
2142 clear_bit(TTY_HUPPED, &tty->flags);
2145 read_lock(&tasklist_lock);
2146 spin_lock_irq(¤t->sighand->siglock);
2147 noctty = (filp->f_flags & O_NOCTTY) ||
2148 device == MKDEV(TTY_MAJOR, 0) ||
2149 device == MKDEV(TTYAUX_MAJOR, 1) ||
2150 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2151 tty->driver->subtype == PTY_TYPE_MASTER);
2154 current->signal->leader &&
2155 !current->signal->tty &&
2156 tty->session == NULL) {
2158 * Don't let a process that only has write access to the tty
2159 * obtain the privileges associated with having a tty as
2160 * controlling terminal (being able to reopen it with full
2161 * access through /dev/tty, being able to perform pushback).
2162 * Many distributions set the group of all ttys to "tty" and
2163 * grant write-only access to all terminals for setgid tty
2164 * binaries, which should not imply full privileges on all ttys.
2166 * This could theoretically break old code that performs open()
2167 * on a write-only file descriptor. In that case, it might be
2168 * necessary to also permit this if
2169 * inode_permission(inode, MAY_READ) == 0.
2171 if (filp->f_mode & FMODE_READ)
2172 __proc_set_tty(tty);
2174 spin_unlock_irq(¤t->sighand->siglock);
2175 read_unlock(&tasklist_lock);
2183 * tty_poll - check tty status
2184 * @filp: file being polled
2185 * @wait: poll wait structures to update
2187 * Call the line discipline polling method to obtain the poll
2188 * status of the device.
2190 * Locking: locks called line discipline but ldisc poll method
2191 * may be re-entered freely by other callers.
2194 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2196 struct tty_struct *tty = file_tty(filp);
2197 struct tty_ldisc *ld;
2200 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2203 ld = tty_ldisc_ref_wait(tty);
2205 ret = ld->ops->poll(tty, filp, wait);
2206 tty_ldisc_deref(ld);
2210 static int __tty_fasync(int fd, struct file *filp, int on)
2212 struct tty_struct *tty = file_tty(filp);
2213 struct tty_ldisc *ldisc;
2214 unsigned long flags;
2217 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2220 retval = fasync_helper(fd, filp, on, &tty->fasync);
2224 ldisc = tty_ldisc_ref(tty);
2226 if (ldisc->ops->fasync)
2227 ldisc->ops->fasync(tty, on);
2228 tty_ldisc_deref(ldisc);
2235 spin_lock_irqsave(&tty->ctrl_lock, flags);
2238 type = PIDTYPE_PGID;
2240 pid = task_pid(current);
2244 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2245 __f_setown(filp, pid, type, 0);
2253 static int tty_fasync(int fd, struct file *filp, int on)
2255 struct tty_struct *tty = file_tty(filp);
2259 retval = __tty_fasync(fd, filp, on);
2266 * tiocsti - fake input character
2267 * @tty: tty to fake input into
2268 * @p: pointer to character
2270 * Fake input to a tty device. Does the necessary locking and
2273 * FIXME: does not honour flow control ??
2276 * Called functions take tty_ldiscs_lock
2277 * current->signal->tty check is safe without locks
2279 * FIXME: may race normal receive processing
2282 static int tiocsti(struct tty_struct *tty, char __user *p)
2285 struct tty_ldisc *ld;
2287 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2289 if (get_user(ch, p))
2291 tty_audit_tiocsti(tty, ch);
2292 ld = tty_ldisc_ref_wait(tty);
2293 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2294 tty_ldisc_deref(ld);
2299 * tiocgwinsz - implement window query ioctl
2301 * @arg: user buffer for result
2303 * Copies the kernel idea of the window size into the user buffer.
2305 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2309 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2313 mutex_lock(&tty->winsize_mutex);
2314 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2315 mutex_unlock(&tty->winsize_mutex);
2317 return err ? -EFAULT: 0;
2321 * tty_do_resize - resize event
2322 * @tty: tty being resized
2323 * @rows: rows (character)
2324 * @cols: cols (character)
2326 * Update the termios variables and send the necessary signals to
2327 * peform a terminal resize correctly
2330 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2335 mutex_lock(&tty->winsize_mutex);
2336 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2339 /* Signal the foreground process group */
2340 pgrp = tty_get_pgrp(tty);
2342 kill_pgrp(pgrp, SIGWINCH, 1);
2347 mutex_unlock(&tty->winsize_mutex);
2350 EXPORT_SYMBOL(tty_do_resize);
2353 * tiocswinsz - implement window size set ioctl
2354 * @tty; tty side of tty
2355 * @arg: user buffer for result
2357 * Copies the user idea of the window size to the kernel. Traditionally
2358 * this is just advisory information but for the Linux console it
2359 * actually has driver level meaning and triggers a VC resize.
2362 * Driver dependent. The default do_resize method takes the
2363 * tty termios mutex and ctrl_lock. The console takes its own lock
2364 * then calls into the default method.
2367 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2369 struct winsize tmp_ws;
2370 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2373 if (tty->ops->resize)
2374 return tty->ops->resize(tty, &tmp_ws);
2376 return tty_do_resize(tty, &tmp_ws);
2380 * tioccons - allow admin to move logical console
2381 * @file: the file to become console
2383 * Allow the administrator to move the redirected console device
2385 * Locking: uses redirect_lock to guard the redirect information
2388 static int tioccons(struct file *file)
2390 if (!capable(CAP_SYS_ADMIN))
2392 if (file->f_op->write == redirected_tty_write) {
2394 spin_lock(&redirect_lock);
2397 spin_unlock(&redirect_lock);
2402 spin_lock(&redirect_lock);
2404 spin_unlock(&redirect_lock);
2407 redirect = get_file(file);
2408 spin_unlock(&redirect_lock);
2413 * fionbio - non blocking ioctl
2414 * @file: file to set blocking value
2415 * @p: user parameter
2417 * Historical tty interfaces had a blocking control ioctl before
2418 * the generic functionality existed. This piece of history is preserved
2419 * in the expected tty API of posix OS's.
2421 * Locking: none, the open file handle ensures it won't go away.
2424 static int fionbio(struct file *file, int __user *p)
2428 if (get_user(nonblock, p))
2431 spin_lock(&file->f_lock);
2433 file->f_flags |= O_NONBLOCK;
2435 file->f_flags &= ~O_NONBLOCK;
2436 spin_unlock(&file->f_lock);
2441 * tiocsctty - set controlling tty
2442 * @tty: tty structure
2443 * @arg: user argument
2445 * This ioctl is used to manage job control. It permits a session
2446 * leader to set this tty as the controlling tty for the session.
2449 * Takes tty_lock() to serialize proc_set_tty() for this tty
2450 * Takes tasklist_lock internally to walk sessions
2451 * Takes ->siglock() when updating signal->tty
2454 static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2459 read_lock(&tasklist_lock);
2461 if (current->signal->leader && (task_session(current) == tty->session))
2465 * The process must be a session leader and
2466 * not have a controlling tty already.
2468 if (!current->signal->leader || current->signal->tty) {
2475 * This tty is already the controlling
2476 * tty for another session group!
2478 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2482 session_clear_tty(tty->session);
2489 /* See the comment in tty_open(). */
2490 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2497 read_unlock(&tasklist_lock);
2503 * tty_get_pgrp - return a ref counted pgrp pid
2506 * Returns a refcounted instance of the pid struct for the process
2507 * group controlling the tty.
2510 struct pid *tty_get_pgrp(struct tty_struct *tty)
2512 unsigned long flags;
2515 spin_lock_irqsave(&tty->ctrl_lock, flags);
2516 pgrp = get_pid(tty->pgrp);
2517 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2521 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2524 * This checks not only the pgrp, but falls back on the pid if no
2525 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2528 * The caller must hold rcu lock or the tasklist lock.
2530 static struct pid *session_of_pgrp(struct pid *pgrp)
2532 struct task_struct *p;
2533 struct pid *sid = NULL;
2535 p = pid_task(pgrp, PIDTYPE_PGID);
2537 p = pid_task(pgrp, PIDTYPE_PID);
2539 sid = task_session(p);
2545 * tiocgpgrp - get process group
2546 * @tty: tty passed by user
2547 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2550 * Obtain the process group of the tty. If there is no process group
2553 * Locking: none. Reference to current->signal->tty is safe.
2556 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2561 * (tty == real_tty) is a cheap way of
2562 * testing if the tty is NOT a master pty.
2564 if (tty == real_tty && current->signal->tty != real_tty)
2566 pid = tty_get_pgrp(real_tty);
2567 ret = put_user(pid_vnr(pid), p);
2573 * tiocspgrp - attempt to set process group
2574 * @tty: tty passed by user
2575 * @real_tty: tty side device matching tty passed by user
2578 * Set the process group of the tty to the session passed. Only
2579 * permitted where the tty session is our session.
2581 * Locking: RCU, ctrl lock
2584 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2588 int retval = tty_check_change(real_tty);
2594 if (!current->signal->tty ||
2595 (current->signal->tty != real_tty) ||
2596 (real_tty->session != task_session(current)))
2598 if (get_user(pgrp_nr, p))
2603 pgrp = find_vpid(pgrp_nr);
2608 if (session_of_pgrp(pgrp) != task_session(current))
2611 spin_lock_irq(&tty->ctrl_lock);
2612 put_pid(real_tty->pgrp);
2613 real_tty->pgrp = get_pid(pgrp);
2614 spin_unlock_irq(&tty->ctrl_lock);
2621 * tiocgsid - get session id
2622 * @tty: tty passed by user
2623 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2624 * @p: pointer to returned session id
2626 * Obtain the session id of the tty. If there is no session
2629 * Locking: none. Reference to current->signal->tty is safe.
2632 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2635 * (tty == real_tty) is a cheap way of
2636 * testing if the tty is NOT a master pty.
2638 if (tty == real_tty && current->signal->tty != real_tty)
2640 if (!real_tty->session)
2642 return put_user(pid_vnr(real_tty->session), p);
2646 * tiocsetd - set line discipline
2648 * @p: pointer to user data
2650 * Set the line discipline according to user request.
2652 * Locking: see tty_set_ldisc, this function is just a helper
2655 static int tiocsetd(struct tty_struct *tty, int __user *p)
2660 if (get_user(ldisc, p))
2663 ret = tty_set_ldisc(tty, ldisc);
2669 * tiocgetd - get line discipline
2671 * @p: pointer to user data
2673 * Retrieves the line discipline id directly from the ldisc.
2675 * Locking: waits for ldisc reference (in case the line discipline
2676 * is changing or the tty is being hungup)
2679 static int tiocgetd(struct tty_struct *tty, int __user *p)
2681 struct tty_ldisc *ld;
2684 ld = tty_ldisc_ref_wait(tty);
2685 ret = put_user(ld->ops->num, p);
2686 tty_ldisc_deref(ld);
2691 * send_break - performed time break
2692 * @tty: device to break on
2693 * @duration: timeout in mS
2695 * Perform a timed break on hardware that lacks its own driver level
2696 * timed break functionality.
2699 * atomic_write_lock serializes
2703 static int send_break(struct tty_struct *tty, unsigned int duration)
2707 if (tty->ops->break_ctl == NULL)
2710 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2711 retval = tty->ops->break_ctl(tty, duration);
2713 /* Do the work ourselves */
2714 if (tty_write_lock(tty, 0) < 0)
2716 retval = tty->ops->break_ctl(tty, -1);
2719 if (!signal_pending(current))
2720 msleep_interruptible(duration);
2721 retval = tty->ops->break_ctl(tty, 0);
2723 tty_write_unlock(tty);
2724 if (signal_pending(current))
2731 * tty_tiocmget - get modem status
2733 * @file: user file pointer
2734 * @p: pointer to result
2736 * Obtain the modem status bits from the tty driver if the feature
2737 * is supported. Return -EINVAL if it is not available.
2739 * Locking: none (up to the driver)
2742 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2744 int retval = -EINVAL;
2746 if (tty->ops->tiocmget) {
2747 retval = tty->ops->tiocmget(tty);
2750 retval = put_user(retval, p);
2756 * tty_tiocmset - set modem status
2758 * @cmd: command - clear bits, set bits or set all
2759 * @p: pointer to desired bits
2761 * Set the modem status bits from the tty driver if the feature
2762 * is supported. Return -EINVAL if it is not available.
2764 * Locking: none (up to the driver)
2767 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2771 unsigned int set, clear, val;
2773 if (tty->ops->tiocmset == NULL)
2776 retval = get_user(val, p);
2792 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2793 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2794 return tty->ops->tiocmset(tty, set, clear);
2797 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2799 int retval = -EINVAL;
2800 struct serial_icounter_struct icount;
2801 memset(&icount, 0, sizeof(icount));
2802 if (tty->ops->get_icount)
2803 retval = tty->ops->get_icount(tty, &icount);
2806 if (copy_to_user(arg, &icount, sizeof(icount)))
2811 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2813 static DEFINE_RATELIMIT_STATE(depr_flags,
2814 DEFAULT_RATELIMIT_INTERVAL,
2815 DEFAULT_RATELIMIT_BURST);
2816 char comm[TASK_COMM_LEN];
2819 if (get_user(flags, &ss->flags))
2822 flags &= ASYNC_DEPRECATED;
2824 if (flags && __ratelimit(&depr_flags))
2825 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2826 __func__, get_task_comm(comm, current), flags);
2830 * if pty, return the slave side (real_tty)
2831 * otherwise, return self
2833 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2835 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2836 tty->driver->subtype == PTY_TYPE_MASTER)
2842 * Split this up, as gcc can choke on it otherwise..
2844 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2846 struct tty_struct *tty = file_tty(file);
2847 struct tty_struct *real_tty;
2848 void __user *p = (void __user *)arg;
2850 struct tty_ldisc *ld;
2852 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2855 real_tty = tty_pair_get_tty(tty);
2858 * Factor out some common prep work
2866 retval = tty_check_change(tty);
2869 if (cmd != TIOCCBRK) {
2870 tty_wait_until_sent(tty, 0);
2871 if (signal_pending(current))
2882 return tiocsti(tty, p);
2884 return tiocgwinsz(real_tty, p);
2886 return tiocswinsz(real_tty, p);
2888 return real_tty != tty ? -EINVAL : tioccons(file);
2890 return fionbio(file, p);
2892 set_bit(TTY_EXCLUSIVE, &tty->flags);
2895 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2899 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2900 return put_user(excl, (int __user *)p);
2903 if (current->signal->tty != tty)
2908 return tiocsctty(real_tty, file, arg);
2910 return tiocgpgrp(tty, real_tty, p);
2912 return tiocspgrp(tty, real_tty, p);
2914 return tiocgsid(tty, real_tty, p);
2916 return tiocgetd(tty, p);
2918 return tiocsetd(tty, p);
2920 if (!capable(CAP_SYS_ADMIN))
2926 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2927 return put_user(ret, (unsigned int __user *)p);
2932 case TIOCSBRK: /* Turn break on, unconditionally */
2933 if (tty->ops->break_ctl)
2934 return tty->ops->break_ctl(tty, -1);
2936 case TIOCCBRK: /* Turn break off, unconditionally */
2937 if (tty->ops->break_ctl)
2938 return tty->ops->break_ctl(tty, 0);
2940 case TCSBRK: /* SVID version: non-zero arg --> no break */
2941 /* non-zero arg means wait for all output data
2942 * to be sent (performed above) but don't send break.
2943 * This is used by the tcdrain() termios function.
2946 return send_break(tty, 250);
2948 case TCSBRKP: /* support for POSIX tcsendbreak() */
2949 return send_break(tty, arg ? arg*100 : 250);
2952 return tty_tiocmget(tty, p);
2956 return tty_tiocmset(tty, cmd, p);
2958 retval = tty_tiocgicount(tty, p);
2959 /* For the moment allow fall through to the old method */
2960 if (retval != -EINVAL)
2967 /* flush tty buffer and allow ldisc to process ioctl */
2968 tty_buffer_flush(tty, NULL);
2973 tty_warn_deprecated_flags(p);
2976 if (tty->ops->ioctl) {
2977 retval = tty->ops->ioctl(tty, cmd, arg);
2978 if (retval != -ENOIOCTLCMD)
2981 ld = tty_ldisc_ref_wait(tty);
2983 if (ld->ops->ioctl) {
2984 retval = ld->ops->ioctl(tty, file, cmd, arg);
2985 if (retval == -ENOIOCTLCMD)
2988 tty_ldisc_deref(ld);
2992 #ifdef CONFIG_COMPAT
2993 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2996 struct tty_struct *tty = file_tty(file);
2997 struct tty_ldisc *ld;
2998 int retval = -ENOIOCTLCMD;
3000 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
3003 if (tty->ops->compat_ioctl) {
3004 retval = tty->ops->compat_ioctl(tty, cmd, arg);
3005 if (retval != -ENOIOCTLCMD)
3009 ld = tty_ldisc_ref_wait(tty);
3010 if (ld->ops->compat_ioctl)
3011 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
3013 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
3014 tty_ldisc_deref(ld);
3020 static int this_tty(const void *t, struct file *file, unsigned fd)
3022 if (likely(file->f_op->read != tty_read))
3024 return file_tty(file) != t ? 0 : fd + 1;
3028 * This implements the "Secure Attention Key" --- the idea is to
3029 * prevent trojan horses by killing all processes associated with this
3030 * tty when the user hits the "Secure Attention Key". Required for
3031 * super-paranoid applications --- see the Orange Book for more details.
3033 * This code could be nicer; ideally it should send a HUP, wait a few
3034 * seconds, then send a INT, and then a KILL signal. But you then
3035 * have to coordinate with the init process, since all processes associated
3036 * with the current tty must be dead before the new getty is allowed
3039 * Now, if it would be correct ;-/ The current code has a nasty hole -
3040 * it doesn't catch files in flight. We may send the descriptor to ourselves
3041 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3043 * Nasty bug: do_SAK is being called in interrupt context. This can
3044 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3046 void __do_SAK(struct tty_struct *tty)
3051 struct task_struct *g, *p;
3052 struct pid *session;
3057 session = tty->session;
3059 tty_ldisc_flush(tty);
3061 tty_driver_flush_buffer(tty);
3063 read_lock(&tasklist_lock);
3064 /* Kill the entire session */
3065 do_each_pid_task(session, PIDTYPE_SID, p) {
3066 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3067 task_pid_nr(p), p->comm);
3068 send_sig(SIGKILL, p, 1);
3069 } while_each_pid_task(session, PIDTYPE_SID, p);
3071 /* Now kill any processes that happen to have the tty open */
3072 do_each_thread(g, p) {
3073 if (p->signal->tty == tty) {
3074 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3075 task_pid_nr(p), p->comm);
3076 send_sig(SIGKILL, p, 1);
3080 i = iterate_fd(p->files, 0, this_tty, tty);
3082 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3083 task_pid_nr(p), p->comm, i - 1);
3084 force_sig(SIGKILL, p);
3087 } while_each_thread(g, p);
3088 read_unlock(&tasklist_lock);
3092 static void do_SAK_work(struct work_struct *work)
3094 struct tty_struct *tty =
3095 container_of(work, struct tty_struct, SAK_work);
3100 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3101 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3102 * the values which we write to it will be identical to the values which it
3103 * already has. --akpm
3105 void do_SAK(struct tty_struct *tty)
3109 schedule_work(&tty->SAK_work);
3112 EXPORT_SYMBOL(do_SAK);
3114 static int dev_match_devt(struct device *dev, const void *data)
3116 const dev_t *devt = data;
3117 return dev->devt == *devt;
3120 /* Must put_device() after it's unused! */
3121 static struct device *tty_get_device(struct tty_struct *tty)
3123 dev_t devt = tty_devnum(tty);
3124 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3131 * This subroutine allocates and initializes a tty structure.
3133 * Locking: none - tty in question is not exposed at this point
3136 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3138 struct tty_struct *tty;
3140 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3144 kref_init(&tty->kref);
3145 tty->magic = TTY_MAGIC;
3146 tty_ldisc_init(tty);
3147 tty->session = NULL;
3149 mutex_init(&tty->legacy_mutex);
3150 mutex_init(&tty->throttle_mutex);
3151 init_rwsem(&tty->termios_rwsem);
3152 mutex_init(&tty->winsize_mutex);
3153 init_ldsem(&tty->ldisc_sem);
3154 init_waitqueue_head(&tty->write_wait);
3155 init_waitqueue_head(&tty->read_wait);
3156 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3157 mutex_init(&tty->atomic_write_lock);
3158 spin_lock_init(&tty->ctrl_lock);
3159 spin_lock_init(&tty->flow_lock);
3160 INIT_LIST_HEAD(&tty->tty_files);
3161 INIT_WORK(&tty->SAK_work, do_SAK_work);
3163 tty->driver = driver;
3164 tty->ops = driver->ops;
3166 tty_line_name(driver, idx, tty->name);
3167 tty->dev = tty_get_device(tty);
3173 * tty_put_char - write one character to a tty
3177 * Write one byte to the tty using the provided put_char method
3178 * if present. Returns the number of characters successfully output.
3180 * Note: the specific put_char operation in the driver layer may go
3181 * away soon. Don't call it directly, use this method
3184 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3186 if (tty->ops->put_char)
3187 return tty->ops->put_char(tty, ch);
3188 return tty->ops->write(tty, &ch, 1);
3190 EXPORT_SYMBOL_GPL(tty_put_char);
3192 struct class *tty_class;
3194 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3195 unsigned int index, unsigned int count)
3199 /* init here, since reused cdevs cause crashes */
3200 driver->cdevs[index] = cdev_alloc();
3201 if (!driver->cdevs[index])
3203 driver->cdevs[index]->ops = &tty_fops;
3204 driver->cdevs[index]->owner = driver->owner;
3205 err = cdev_add(driver->cdevs[index], dev, count);
3207 kobject_put(&driver->cdevs[index]->kobj);
3212 * tty_register_device - register a tty device
3213 * @driver: the tty driver that describes the tty device
3214 * @index: the index in the tty driver for this tty device
3215 * @device: a struct device that is associated with this tty device.
3216 * This field is optional, if there is no known struct device
3217 * for this tty device it can be set to NULL safely.
3219 * Returns a pointer to the struct device for this tty device
3220 * (or ERR_PTR(-EFOO) on error).
3222 * This call is required to be made to register an individual tty device
3223 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3224 * that bit is not set, this function should not be called by a tty
3230 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3231 struct device *device)
3233 return tty_register_device_attr(driver, index, device, NULL, NULL);
3235 EXPORT_SYMBOL(tty_register_device);
3237 static void tty_device_create_release(struct device *dev)
3239 dev_dbg(dev, "releasing...\n");
3244 * tty_register_device_attr - register a tty device
3245 * @driver: the tty driver that describes the tty device
3246 * @index: the index in the tty driver for this tty device
3247 * @device: a struct device that is associated with this tty device.
3248 * This field is optional, if there is no known struct device
3249 * for this tty device it can be set to NULL safely.
3250 * @drvdata: Driver data to be set to device.
3251 * @attr_grp: Attribute group to be set on device.
3253 * Returns a pointer to the struct device for this tty device
3254 * (or ERR_PTR(-EFOO) on error).
3256 * This call is required to be made to register an individual tty device
3257 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3258 * that bit is not set, this function should not be called by a tty
3263 struct device *tty_register_device_attr(struct tty_driver *driver,
3264 unsigned index, struct device *device,
3266 const struct attribute_group **attr_grp)
3269 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3270 struct device *dev = NULL;
3271 int retval = -ENODEV;
3274 if (index >= driver->num) {
3275 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3276 driver->name, index);
3277 return ERR_PTR(-EINVAL);
3280 if (driver->type == TTY_DRIVER_TYPE_PTY)
3281 pty_line_name(driver, index, name);
3283 tty_line_name(driver, index, name);
3285 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3286 retval = tty_cdev_add(driver, devt, index, 1);
3292 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3299 dev->class = tty_class;
3300 dev->parent = device;
3301 dev->release = tty_device_create_release;
3302 dev_set_name(dev, "%s", name);
3303 dev->groups = attr_grp;
3304 dev_set_drvdata(dev, drvdata);
3306 retval = device_register(dev);
3315 cdev_del(driver->cdevs[index]);
3316 driver->cdevs[index] = NULL;
3318 return ERR_PTR(retval);
3320 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3323 * tty_unregister_device - unregister a tty device
3324 * @driver: the tty driver that describes the tty device
3325 * @index: the index in the tty driver for this tty device
3327 * If a tty device is registered with a call to tty_register_device() then
3328 * this function must be called when the tty device is gone.
3333 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3335 device_destroy(tty_class,
3336 MKDEV(driver->major, driver->minor_start) + index);
3337 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3338 cdev_del(driver->cdevs[index]);
3339 driver->cdevs[index] = NULL;
3342 EXPORT_SYMBOL(tty_unregister_device);
3345 * __tty_alloc_driver -- allocate tty driver
3346 * @lines: count of lines this driver can handle at most
3347 * @owner: module which is repsonsible for this driver
3348 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3350 * This should not be called directly, some of the provided macros should be
3351 * used instead. Use IS_ERR and friends on @retval.
3353 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3354 unsigned long flags)
3356 struct tty_driver *driver;
3357 unsigned int cdevs = 1;
3360 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3361 return ERR_PTR(-EINVAL);
3363 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3365 return ERR_PTR(-ENOMEM);
3367 kref_init(&driver->kref);
3368 driver->magic = TTY_DRIVER_MAGIC;
3369 driver->num = lines;
3370 driver->owner = owner;
3371 driver->flags = flags;
3373 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3374 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3376 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3378 if (!driver->ttys || !driver->termios) {
3384 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3385 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3387 if (!driver->ports) {
3394 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3395 if (!driver->cdevs) {
3402 kfree(driver->ports);
3403 kfree(driver->ttys);
3404 kfree(driver->termios);
3405 kfree(driver->cdevs);
3407 return ERR_PTR(err);
3409 EXPORT_SYMBOL(__tty_alloc_driver);
3411 static void destruct_tty_driver(struct kref *kref)
3413 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3415 struct ktermios *tp;
3417 if (driver->flags & TTY_DRIVER_INSTALLED) {
3419 * Free the termios and termios_locked structures because
3420 * we don't want to get memory leaks when modular tty
3421 * drivers are removed from the kernel.
3423 for (i = 0; i < driver->num; i++) {
3424 tp = driver->termios[i];
3426 driver->termios[i] = NULL;
3429 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3430 tty_unregister_device(driver, i);
3432 proc_tty_unregister_driver(driver);
3433 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3434 cdev_del(driver->cdevs[0]);
3436 kfree(driver->cdevs);
3437 kfree(driver->ports);
3438 kfree(driver->termios);
3439 kfree(driver->ttys);
3443 void tty_driver_kref_put(struct tty_driver *driver)
3445 kref_put(&driver->kref, destruct_tty_driver);
3447 EXPORT_SYMBOL(tty_driver_kref_put);
3449 void tty_set_operations(struct tty_driver *driver,
3450 const struct tty_operations *op)
3454 EXPORT_SYMBOL(tty_set_operations);
3456 void put_tty_driver(struct tty_driver *d)
3458 tty_driver_kref_put(d);
3460 EXPORT_SYMBOL(put_tty_driver);
3463 * Called by a tty driver to register itself.
3465 int tty_register_driver(struct tty_driver *driver)
3472 if (!driver->major) {
3473 error = alloc_chrdev_region(&dev, driver->minor_start,
3474 driver->num, driver->name);
3476 driver->major = MAJOR(dev);
3477 driver->minor_start = MINOR(dev);
3480 dev = MKDEV(driver->major, driver->minor_start);
3481 error = register_chrdev_region(dev, driver->num, driver->name);
3486 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3487 error = tty_cdev_add(driver, dev, 0, driver->num);
3489 goto err_unreg_char;
3492 mutex_lock(&tty_mutex);
3493 list_add(&driver->tty_drivers, &tty_drivers);
3494 mutex_unlock(&tty_mutex);
3496 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3497 for (i = 0; i < driver->num; i++) {
3498 d = tty_register_device(driver, i, NULL);
3501 goto err_unreg_devs;
3505 proc_tty_register_driver(driver);
3506 driver->flags |= TTY_DRIVER_INSTALLED;
3510 for (i--; i >= 0; i--)
3511 tty_unregister_device(driver, i);
3513 mutex_lock(&tty_mutex);
3514 list_del(&driver->tty_drivers);
3515 mutex_unlock(&tty_mutex);
3518 unregister_chrdev_region(dev, driver->num);
3522 EXPORT_SYMBOL(tty_register_driver);
3525 * Called by a tty driver to unregister itself.
3527 int tty_unregister_driver(struct tty_driver *driver)
3531 if (driver->refcount)
3534 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3536 mutex_lock(&tty_mutex);
3537 list_del(&driver->tty_drivers);
3538 mutex_unlock(&tty_mutex);
3542 EXPORT_SYMBOL(tty_unregister_driver);
3544 dev_t tty_devnum(struct tty_struct *tty)
3546 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3548 EXPORT_SYMBOL(tty_devnum);
3550 void tty_default_fops(struct file_operations *fops)
3556 * Initialize the console device. This is called *early*, so
3557 * we can't necessarily depend on lots of kernel help here.
3558 * Just do some early initializations, and do the complex setup
3561 void __init console_init(void)
3565 /* Setup the default TTY line discipline. */
3569 * set up the console device so that later boot sequences can
3570 * inform about problems etc..
3572 call = __con_initcall_start;
3573 while (call < __con_initcall_end) {
3579 static char *tty_devnode(struct device *dev, umode_t *mode)
3583 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3584 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3589 static int __init tty_class_init(void)
3591 tty_class = class_create(THIS_MODULE, "tty");
3592 if (IS_ERR(tty_class))
3593 return PTR_ERR(tty_class);
3594 tty_class->devnode = tty_devnode;
3598 postcore_initcall(tty_class_init);
3600 /* 3/2004 jmc: why do these devices exist? */
3601 static struct cdev tty_cdev, console_cdev;
3603 static ssize_t show_cons_active(struct device *dev,
3604 struct device_attribute *attr, char *buf)
3606 struct console *cs[16];
3612 for_each_console(c) {
3617 if ((c->flags & CON_ENABLED) == 0)
3620 if (i >= ARRAY_SIZE(cs))
3624 int index = cs[i]->index;
3625 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3627 /* don't resolve tty0 as some programs depend on it */
3628 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3629 count += tty_line_name(drv, index, buf + count);
3631 count += sprintf(buf + count, "%s%d",
3632 cs[i]->name, cs[i]->index);
3634 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3640 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3642 static struct attribute *cons_dev_attrs[] = {
3643 &dev_attr_active.attr,
3647 ATTRIBUTE_GROUPS(cons_dev);
3649 static struct device *consdev;
3651 void console_sysfs_notify(void)
3654 sysfs_notify(&consdev->kobj, NULL, "active");
3658 * Ok, now we can initialize the rest of the tty devices and can count
3659 * on memory allocations, interrupts etc..
3661 int __init tty_init(void)
3663 cdev_init(&tty_cdev, &tty_fops);
3664 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3665 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3666 panic("Couldn't register /dev/tty driver\n");
3667 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3669 cdev_init(&console_cdev, &console_fops);
3670 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3671 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3672 panic("Couldn't register /dev/console driver\n");
3673 consdev = device_create_with_groups(tty_class, NULL,
3674 MKDEV(TTYAUX_MAJOR, 1), NULL,
3675 cons_dev_groups, "console");
3676 if (IS_ERR(consdev))
3680 vty_init(&console_fops);