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];
1393 tty->termios = tty->driver->init_termios;
1395 /* Compatibility until drivers always set this */
1396 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1397 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1399 EXPORT_SYMBOL_GPL(tty_init_termios);
1401 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1403 tty_init_termios(tty);
1404 tty_driver_kref_get(driver);
1406 driver->ttys[tty->index] = tty;
1409 EXPORT_SYMBOL_GPL(tty_standard_install);
1412 * tty_driver_install_tty() - install a tty entry in the driver
1413 * @driver: the driver for the tty
1416 * Install a tty object into the driver tables. The tty->index field
1417 * will be set by the time this is called. This method is responsible
1418 * for ensuring any need additional structures are allocated and
1421 * Locking: tty_mutex for now
1423 static int tty_driver_install_tty(struct tty_driver *driver,
1424 struct tty_struct *tty)
1426 return driver->ops->install ? driver->ops->install(driver, tty) :
1427 tty_standard_install(driver, tty);
1431 * tty_driver_remove_tty() - remove a tty from the driver tables
1432 * @driver: the driver for the tty
1433 * @idx: the minor number
1435 * Remvoe a tty object from the driver tables. The tty->index field
1436 * will be set by the time this is called.
1438 * Locking: tty_mutex for now
1440 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1442 if (driver->ops->remove)
1443 driver->ops->remove(driver, tty);
1445 driver->ttys[tty->index] = NULL;
1449 * tty_reopen() - fast re-open of an open tty
1450 * @tty - the tty to open
1452 * Return 0 on success, -errno on error.
1453 * Re-opens on master ptys are not allowed and return -EIO.
1455 * Locking: Caller must hold tty_lock
1457 static int tty_reopen(struct tty_struct *tty)
1459 struct tty_driver *driver = tty->driver;
1461 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1462 driver->subtype == PTY_TYPE_MASTER)
1468 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1473 WARN_ON(!tty->ldisc);
1479 * tty_init_dev - initialise a tty device
1480 * @driver: tty driver we are opening a device on
1481 * @idx: device index
1482 * @ret_tty: returned tty structure
1484 * Prepare a tty device. This may not be a "new" clean device but
1485 * could also be an active device. The pty drivers require special
1486 * handling because of this.
1489 * The function is called under the tty_mutex, which
1490 * protects us from the tty struct or driver itself going away.
1492 * On exit the tty device has the line discipline attached and
1493 * a reference count of 1. If a pair was created for pty/tty use
1494 * and the other was a pty master then it too has a reference count of 1.
1496 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1497 * failed open. The new code protects the open with a mutex, so it's
1498 * really quite straightforward. The mutex locking can probably be
1499 * relaxed for the (most common) case of reopening a tty.
1502 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1504 struct tty_struct *tty;
1508 * First time open is complex, especially for PTY devices.
1509 * This code guarantees that either everything succeeds and the
1510 * TTY is ready for operation, or else the table slots are vacated
1511 * and the allocated memory released. (Except that the termios
1512 * and locked termios may be retained.)
1515 if (!try_module_get(driver->owner))
1516 return ERR_PTR(-ENODEV);
1518 tty = alloc_tty_struct(driver, idx);
1521 goto err_module_put;
1525 retval = tty_driver_install_tty(driver, tty);
1530 tty->port = driver->ports[idx];
1532 WARN_RATELIMIT(!tty->port,
1533 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1534 __func__, tty->driver->name);
1536 tty->port->itty = tty;
1539 * Structures all installed ... call the ldisc open routines.
1540 * If we fail here just call release_tty to clean up. No need
1541 * to decrement the use counts, as release_tty doesn't care.
1543 retval = tty_ldisc_setup(tty, tty->link);
1545 goto err_release_tty;
1546 /* Return the tty locked so that it cannot vanish under the caller */
1551 free_tty_struct(tty);
1553 module_put(driver->owner);
1554 return ERR_PTR(retval);
1556 /* call the tty release_tty routine to clean out this slot */
1559 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1561 release_tty(tty, idx);
1562 return ERR_PTR(retval);
1565 static void tty_free_termios(struct tty_struct *tty)
1567 struct ktermios *tp;
1568 int idx = tty->index;
1570 /* If the port is going to reset then it has no termios to save */
1571 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1574 /* Stash the termios data */
1575 tp = tty->driver->termios[idx];
1577 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1580 tty->driver->termios[idx] = tp;
1586 * tty_flush_works - flush all works of a tty/pty pair
1587 * @tty: tty device to flush works for (or either end of a pty pair)
1589 * Sync flush all works belonging to @tty (and the 'other' tty).
1591 static void tty_flush_works(struct tty_struct *tty)
1593 flush_work(&tty->SAK_work);
1594 flush_work(&tty->hangup_work);
1596 flush_work(&tty->link->SAK_work);
1597 flush_work(&tty->link->hangup_work);
1602 * release_one_tty - release tty structure memory
1603 * @kref: kref of tty we are obliterating
1605 * Releases memory associated with a tty structure, and clears out the
1606 * driver table slots. This function is called when a device is no longer
1607 * in use. It also gets called when setup of a device fails.
1610 * takes the file list lock internally when working on the list
1611 * of ttys that the driver keeps.
1613 * This method gets called from a work queue so that the driver private
1614 * cleanup ops can sleep (needed for USB at least)
1616 static void release_one_tty(struct work_struct *work)
1618 struct tty_struct *tty =
1619 container_of(work, struct tty_struct, hangup_work);
1620 struct tty_driver *driver = tty->driver;
1621 struct module *owner = driver->owner;
1623 if (tty->ops->cleanup)
1624 tty->ops->cleanup(tty);
1627 tty_driver_kref_put(driver);
1630 spin_lock(&tty_files_lock);
1631 list_del_init(&tty->tty_files);
1632 spin_unlock(&tty_files_lock);
1635 put_pid(tty->session);
1636 free_tty_struct(tty);
1639 static void queue_release_one_tty(struct kref *kref)
1641 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1643 /* The hangup queue is now free so we can reuse it rather than
1644 waste a chunk of memory for each port */
1645 INIT_WORK(&tty->hangup_work, release_one_tty);
1646 schedule_work(&tty->hangup_work);
1650 * tty_kref_put - release a tty kref
1653 * Release a reference to a tty device and if need be let the kref
1654 * layer destruct the object for us
1657 void tty_kref_put(struct tty_struct *tty)
1660 kref_put(&tty->kref, queue_release_one_tty);
1662 EXPORT_SYMBOL(tty_kref_put);
1665 * release_tty - release tty structure memory
1667 * Release both @tty and a possible linked partner (think pty pair),
1668 * and decrement the refcount of the backing module.
1672 * takes the file list lock internally when working on the list
1673 * of ttys that the driver keeps.
1676 static void release_tty(struct tty_struct *tty, int idx)
1678 /* This should always be true but check for the moment */
1679 WARN_ON(tty->index != idx);
1680 WARN_ON(!mutex_is_locked(&tty_mutex));
1681 if (tty->ops->shutdown)
1682 tty->ops->shutdown(tty);
1683 tty_free_termios(tty);
1684 tty_driver_remove_tty(tty->driver, tty);
1685 tty->port->itty = NULL;
1687 tty->link->port->itty = NULL;
1688 tty_buffer_cancel_work(tty->port);
1690 tty_kref_put(tty->link);
1695 * tty_release_checks - check a tty before real release
1696 * @tty: tty to check
1697 * @o_tty: link of @tty (if any)
1698 * @idx: index of the tty
1700 * Performs some paranoid checking before true release of the @tty.
1701 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1703 static int tty_release_checks(struct tty_struct *tty, int idx)
1705 #ifdef TTY_PARANOIA_CHECK
1706 if (idx < 0 || idx >= tty->driver->num) {
1707 tty_debug(tty, "bad idx %d\n", idx);
1711 /* not much to check for devpts */
1712 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1715 if (tty != tty->driver->ttys[idx]) {
1716 tty_debug(tty, "bad driver table[%d] = %p\n",
1717 idx, tty->driver->ttys[idx]);
1720 if (tty->driver->other) {
1721 struct tty_struct *o_tty = tty->link;
1723 if (o_tty != tty->driver->other->ttys[idx]) {
1724 tty_debug(tty, "bad other table[%d] = %p\n",
1725 idx, tty->driver->other->ttys[idx]);
1728 if (o_tty->link != tty) {
1729 tty_debug(tty, "bad link = %p\n", o_tty->link);
1738 * tty_release - vfs callback for close
1739 * @inode: inode of tty
1740 * @filp: file pointer for handle to tty
1742 * Called the last time each file handle is closed that references
1743 * this tty. There may however be several such references.
1746 * Takes bkl. See tty_release_dev
1748 * Even releasing the tty structures is a tricky business.. We have
1749 * to be very careful that the structures are all released at the
1750 * same time, as interrupts might otherwise get the wrong pointers.
1752 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1753 * lead to double frees or releasing memory still in use.
1756 int tty_release(struct inode *inode, struct file *filp)
1758 struct tty_struct *tty = file_tty(filp);
1759 struct tty_struct *o_tty = NULL;
1760 int do_sleep, final;
1765 if (tty_paranoia_check(tty, inode, __func__))
1769 check_tty_count(tty, __func__);
1771 __tty_fasync(-1, filp, 0);
1774 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1775 tty->driver->subtype == PTY_TYPE_MASTER)
1778 if (tty_release_checks(tty, idx)) {
1783 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1785 if (tty->ops->close)
1786 tty->ops->close(tty, filp);
1788 /* If tty is pty master, lock the slave pty (stable lock order) */
1789 tty_lock_slave(o_tty);
1792 * Sanity check: if tty->count is going to zero, there shouldn't be
1793 * any waiters on tty->read_wait or tty->write_wait. We test the
1794 * wait queues and kick everyone out _before_ actually starting to
1795 * close. This ensures that we won't block while releasing the tty
1798 * The test for the o_tty closing is necessary, since the master and
1799 * slave sides may close in any order. If the slave side closes out
1800 * first, its count will be one, since the master side holds an open.
1801 * Thus this test wouldn't be triggered at the time the slave closed,
1807 if (tty->count <= 1) {
1808 if (waitqueue_active(&tty->read_wait)) {
1809 wake_up_poll(&tty->read_wait, POLLIN);
1812 if (waitqueue_active(&tty->write_wait)) {
1813 wake_up_poll(&tty->write_wait, POLLOUT);
1817 if (o_tty && o_tty->count <= 1) {
1818 if (waitqueue_active(&o_tty->read_wait)) {
1819 wake_up_poll(&o_tty->read_wait, POLLIN);
1822 if (waitqueue_active(&o_tty->write_wait)) {
1823 wake_up_poll(&o_tty->write_wait, POLLOUT);
1832 tty_warn(tty, "read/write wait queue active!\n");
1834 schedule_timeout_killable(timeout);
1835 if (timeout < 120 * HZ)
1836 timeout = 2 * timeout + 1;
1838 timeout = MAX_SCHEDULE_TIMEOUT;
1842 if (--o_tty->count < 0) {
1843 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1847 if (--tty->count < 0) {
1848 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1853 * We've decremented tty->count, so we need to remove this file
1854 * descriptor off the tty->tty_files list; this serves two
1856 * - check_tty_count sees the correct number of file descriptors
1857 * associated with this tty.
1858 * - do_tty_hangup no longer sees this file descriptor as
1859 * something that needs to be handled for hangups.
1864 * Perform some housekeeping before deciding whether to return.
1866 * If _either_ side is closing, make sure there aren't any
1867 * processes that still think tty or o_tty is their controlling
1871 read_lock(&tasklist_lock);
1872 session_clear_tty(tty->session);
1874 session_clear_tty(o_tty->session);
1875 read_unlock(&tasklist_lock);
1878 /* check whether both sides are closing ... */
1879 final = !tty->count && !(o_tty && o_tty->count);
1881 tty_unlock_slave(o_tty);
1884 /* At this point, the tty->count == 0 should ensure a dead tty
1885 cannot be re-opened by a racing opener */
1890 tty_debug_hangup(tty, "final close\n");
1892 * Ask the line discipline code to release its structures
1894 tty_ldisc_release(tty);
1896 /* Wait for pending work before tty destruction commmences */
1897 tty_flush_works(tty);
1899 tty_debug_hangup(tty, "freeing structure\n");
1901 * The release_tty function takes care of the details of clearing
1902 * the slots and preserving the termios structure. The tty_unlock_pair
1903 * should be safe as we keep a kref while the tty is locked (so the
1904 * unlock never unlocks a freed tty).
1906 mutex_lock(&tty_mutex);
1907 release_tty(tty, idx);
1908 mutex_unlock(&tty_mutex);
1914 * tty_open_current_tty - get locked tty of current task
1915 * @device: device number
1916 * @filp: file pointer to tty
1917 * @return: locked tty of the current task iff @device is /dev/tty
1919 * Performs a re-open of the current task's controlling tty.
1921 * We cannot return driver and index like for the other nodes because
1922 * devpts will not work then. It expects inodes to be from devpts FS.
1924 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1926 struct tty_struct *tty;
1929 if (device != MKDEV(TTYAUX_MAJOR, 0))
1932 tty = get_current_tty();
1934 return ERR_PTR(-ENXIO);
1936 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1939 tty_kref_put(tty); /* safe to drop the kref now */
1941 retval = tty_reopen(tty);
1944 tty = ERR_PTR(retval);
1950 * tty_lookup_driver - lookup a tty driver for a given device file
1951 * @device: device number
1952 * @filp: file pointer to tty
1953 * @noctty: set if the device should not become a controlling tty
1954 * @index: index for the device in the @return driver
1955 * @return: driver for this inode (with increased refcount)
1957 * If @return is not erroneous, the caller is responsible to decrement the
1958 * refcount by tty_driver_kref_put.
1960 * Locking: tty_mutex protects get_tty_driver
1962 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1965 struct tty_driver *driver;
1969 case MKDEV(TTY_MAJOR, 0): {
1970 extern struct tty_driver *console_driver;
1971 driver = tty_driver_kref_get(console_driver);
1972 *index = fg_console;
1976 case MKDEV(TTYAUX_MAJOR, 1): {
1977 struct tty_driver *console_driver = console_device(index);
1978 if (console_driver) {
1979 driver = tty_driver_kref_get(console_driver);
1981 /* Don't let /dev/console block */
1982 filp->f_flags |= O_NONBLOCK;
1986 return ERR_PTR(-ENODEV);
1989 driver = get_tty_driver(device, index);
1991 return ERR_PTR(-ENODEV);
1998 * tty_open - open a tty device
1999 * @inode: inode of device file
2000 * @filp: file pointer to tty
2002 * tty_open and tty_release keep up the tty count that contains the
2003 * number of opens done on a tty. We cannot use the inode-count, as
2004 * different inodes might point to the same tty.
2006 * Open-counting is needed for pty masters, as well as for keeping
2007 * track of serial lines: DTR is dropped when the last close happens.
2008 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2010 * The termios state of a pty is reset on first open so that
2011 * settings don't persist across reuse.
2013 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2014 * tty->count should protect the rest.
2015 * ->siglock protects ->signal/->sighand
2017 * Note: the tty_unlock/lock cases without a ref are only safe due to
2021 static int tty_open(struct inode *inode, struct file *filp)
2023 struct tty_struct *tty;
2025 struct tty_driver *driver = NULL;
2027 dev_t device = inode->i_rdev;
2028 unsigned saved_flags = filp->f_flags;
2030 nonseekable_open(inode, filp);
2033 retval = tty_alloc_file(filp);
2040 tty = tty_open_current_tty(device, filp);
2042 mutex_lock(&tty_mutex);
2043 driver = tty_lookup_driver(device, filp, &index);
2044 if (IS_ERR(driver)) {
2045 retval = PTR_ERR(driver);
2049 /* check whether we're reopening an existing tty */
2050 tty = tty_driver_lookup_tty(driver, inode, index);
2052 retval = PTR_ERR(tty);
2057 mutex_unlock(&tty_mutex);
2058 retval = tty_lock_interruptible(tty);
2060 if (retval == -EINTR)
2061 retval = -ERESTARTSYS;
2064 /* safe to drop the kref from tty_driver_lookup_tty() */
2066 retval = tty_reopen(tty);
2069 tty = ERR_PTR(retval);
2071 } else { /* Returns with the tty_lock held for now */
2072 tty = tty_init_dev(driver, index);
2073 mutex_unlock(&tty_mutex);
2076 tty_driver_kref_put(driver);
2080 retval = PTR_ERR(tty);
2081 if (retval != -EAGAIN || signal_pending(current))
2083 tty_free_file(filp);
2088 tty_add_file(tty, filp);
2090 check_tty_count(tty, __func__);
2091 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2094 retval = tty->ops->open(tty, filp);
2097 filp->f_flags = saved_flags;
2100 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2102 tty_unlock(tty); /* need to call tty_release without BTM */
2103 tty_release(inode, filp);
2104 if (retval != -ERESTARTSYS)
2107 if (signal_pending(current))
2112 * Need to reset f_op in case a hangup happened.
2114 if (tty_hung_up_p(filp))
2115 filp->f_op = &tty_fops;
2118 clear_bit(TTY_HUPPED, &tty->flags);
2121 read_lock(&tasklist_lock);
2122 spin_lock_irq(¤t->sighand->siglock);
2123 noctty = (filp->f_flags & O_NOCTTY) ||
2124 device == MKDEV(TTY_MAJOR, 0) ||
2125 device == MKDEV(TTYAUX_MAJOR, 1) ||
2126 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2127 tty->driver->subtype == PTY_TYPE_MASTER);
2130 current->signal->leader &&
2131 !current->signal->tty &&
2132 tty->session == NULL) {
2134 * Don't let a process that only has write access to the tty
2135 * obtain the privileges associated with having a tty as
2136 * controlling terminal (being able to reopen it with full
2137 * access through /dev/tty, being able to perform pushback).
2138 * Many distributions set the group of all ttys to "tty" and
2139 * grant write-only access to all terminals for setgid tty
2140 * binaries, which should not imply full privileges on all ttys.
2142 * This could theoretically break old code that performs open()
2143 * on a write-only file descriptor. In that case, it might be
2144 * necessary to also permit this if
2145 * inode_permission(inode, MAY_READ) == 0.
2147 if (filp->f_mode & FMODE_READ)
2148 __proc_set_tty(tty);
2150 spin_unlock_irq(¤t->sighand->siglock);
2151 read_unlock(&tasklist_lock);
2155 mutex_unlock(&tty_mutex);
2157 /* after locks to avoid deadlock */
2158 if (!IS_ERR_OR_NULL(driver))
2159 tty_driver_kref_put(driver);
2161 tty_free_file(filp);
2168 * tty_poll - check tty status
2169 * @filp: file being polled
2170 * @wait: poll wait structures to update
2172 * Call the line discipline polling method to obtain the poll
2173 * status of the device.
2175 * Locking: locks called line discipline but ldisc poll method
2176 * may be re-entered freely by other callers.
2179 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2181 struct tty_struct *tty = file_tty(filp);
2182 struct tty_ldisc *ld;
2185 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2188 ld = tty_ldisc_ref_wait(tty);
2190 ret = ld->ops->poll(tty, filp, wait);
2191 tty_ldisc_deref(ld);
2195 static int __tty_fasync(int fd, struct file *filp, int on)
2197 struct tty_struct *tty = file_tty(filp);
2198 struct tty_ldisc *ldisc;
2199 unsigned long flags;
2202 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2205 retval = fasync_helper(fd, filp, on, &tty->fasync);
2209 ldisc = tty_ldisc_ref(tty);
2211 if (ldisc->ops->fasync)
2212 ldisc->ops->fasync(tty, on);
2213 tty_ldisc_deref(ldisc);
2220 spin_lock_irqsave(&tty->ctrl_lock, flags);
2223 type = PIDTYPE_PGID;
2225 pid = task_pid(current);
2229 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2230 __f_setown(filp, pid, type, 0);
2238 static int tty_fasync(int fd, struct file *filp, int on)
2240 struct tty_struct *tty = file_tty(filp);
2244 retval = __tty_fasync(fd, filp, on);
2251 * tiocsti - fake input character
2252 * @tty: tty to fake input into
2253 * @p: pointer to character
2255 * Fake input to a tty device. Does the necessary locking and
2258 * FIXME: does not honour flow control ??
2261 * Called functions take tty_ldiscs_lock
2262 * current->signal->tty check is safe without locks
2264 * FIXME: may race normal receive processing
2267 static int tiocsti(struct tty_struct *tty, char __user *p)
2270 struct tty_ldisc *ld;
2272 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2274 if (get_user(ch, p))
2276 tty_audit_tiocsti(tty, ch);
2277 ld = tty_ldisc_ref_wait(tty);
2278 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2279 tty_ldisc_deref(ld);
2284 * tiocgwinsz - implement window query ioctl
2286 * @arg: user buffer for result
2288 * Copies the kernel idea of the window size into the user buffer.
2290 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2294 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2298 mutex_lock(&tty->winsize_mutex);
2299 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2300 mutex_unlock(&tty->winsize_mutex);
2302 return err ? -EFAULT: 0;
2306 * tty_do_resize - resize event
2307 * @tty: tty being resized
2308 * @rows: rows (character)
2309 * @cols: cols (character)
2311 * Update the termios variables and send the necessary signals to
2312 * peform a terminal resize correctly
2315 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2320 mutex_lock(&tty->winsize_mutex);
2321 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2324 /* Signal the foreground process group */
2325 pgrp = tty_get_pgrp(tty);
2327 kill_pgrp(pgrp, SIGWINCH, 1);
2332 mutex_unlock(&tty->winsize_mutex);
2335 EXPORT_SYMBOL(tty_do_resize);
2338 * tiocswinsz - implement window size set ioctl
2339 * @tty; tty side of tty
2340 * @arg: user buffer for result
2342 * Copies the user idea of the window size to the kernel. Traditionally
2343 * this is just advisory information but for the Linux console it
2344 * actually has driver level meaning and triggers a VC resize.
2347 * Driver dependent. The default do_resize method takes the
2348 * tty termios mutex and ctrl_lock. The console takes its own lock
2349 * then calls into the default method.
2352 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2354 struct winsize tmp_ws;
2355 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2358 if (tty->ops->resize)
2359 return tty->ops->resize(tty, &tmp_ws);
2361 return tty_do_resize(tty, &tmp_ws);
2365 * tioccons - allow admin to move logical console
2366 * @file: the file to become console
2368 * Allow the administrator to move the redirected console device
2370 * Locking: uses redirect_lock to guard the redirect information
2373 static int tioccons(struct file *file)
2375 if (!capable(CAP_SYS_ADMIN))
2377 if (file->f_op->write == redirected_tty_write) {
2379 spin_lock(&redirect_lock);
2382 spin_unlock(&redirect_lock);
2387 spin_lock(&redirect_lock);
2389 spin_unlock(&redirect_lock);
2392 redirect = get_file(file);
2393 spin_unlock(&redirect_lock);
2398 * fionbio - non blocking ioctl
2399 * @file: file to set blocking value
2400 * @p: user parameter
2402 * Historical tty interfaces had a blocking control ioctl before
2403 * the generic functionality existed. This piece of history is preserved
2404 * in the expected tty API of posix OS's.
2406 * Locking: none, the open file handle ensures it won't go away.
2409 static int fionbio(struct file *file, int __user *p)
2413 if (get_user(nonblock, p))
2416 spin_lock(&file->f_lock);
2418 file->f_flags |= O_NONBLOCK;
2420 file->f_flags &= ~O_NONBLOCK;
2421 spin_unlock(&file->f_lock);
2426 * tiocsctty - set controlling tty
2427 * @tty: tty structure
2428 * @arg: user argument
2430 * This ioctl is used to manage job control. It permits a session
2431 * leader to set this tty as the controlling tty for the session.
2434 * Takes tty_lock() to serialize proc_set_tty() for this tty
2435 * Takes tasklist_lock internally to walk sessions
2436 * Takes ->siglock() when updating signal->tty
2439 static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2444 read_lock(&tasklist_lock);
2446 if (current->signal->leader && (task_session(current) == tty->session))
2450 * The process must be a session leader and
2451 * not have a controlling tty already.
2453 if (!current->signal->leader || current->signal->tty) {
2460 * This tty is already the controlling
2461 * tty for another session group!
2463 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2467 session_clear_tty(tty->session);
2474 /* See the comment in tty_open(). */
2475 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2482 read_unlock(&tasklist_lock);
2488 * tty_get_pgrp - return a ref counted pgrp pid
2491 * Returns a refcounted instance of the pid struct for the process
2492 * group controlling the tty.
2495 struct pid *tty_get_pgrp(struct tty_struct *tty)
2497 unsigned long flags;
2500 spin_lock_irqsave(&tty->ctrl_lock, flags);
2501 pgrp = get_pid(tty->pgrp);
2502 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2506 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2509 * This checks not only the pgrp, but falls back on the pid if no
2510 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2513 * The caller must hold rcu lock or the tasklist lock.
2515 static struct pid *session_of_pgrp(struct pid *pgrp)
2517 struct task_struct *p;
2518 struct pid *sid = NULL;
2520 p = pid_task(pgrp, PIDTYPE_PGID);
2522 p = pid_task(pgrp, PIDTYPE_PID);
2524 sid = task_session(p);
2530 * tiocgpgrp - get process group
2531 * @tty: tty passed by user
2532 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2535 * Obtain the process group of the tty. If there is no process group
2538 * Locking: none. Reference to current->signal->tty is safe.
2541 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2546 * (tty == real_tty) is a cheap way of
2547 * testing if the tty is NOT a master pty.
2549 if (tty == real_tty && current->signal->tty != real_tty)
2551 pid = tty_get_pgrp(real_tty);
2552 ret = put_user(pid_vnr(pid), p);
2558 * tiocspgrp - attempt to set process group
2559 * @tty: tty passed by user
2560 * @real_tty: tty side device matching tty passed by user
2563 * Set the process group of the tty to the session passed. Only
2564 * permitted where the tty session is our session.
2566 * Locking: RCU, ctrl lock
2569 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2573 int retval = tty_check_change(real_tty);
2579 if (!current->signal->tty ||
2580 (current->signal->tty != real_tty) ||
2581 (real_tty->session != task_session(current)))
2583 if (get_user(pgrp_nr, p))
2588 pgrp = find_vpid(pgrp_nr);
2593 if (session_of_pgrp(pgrp) != task_session(current))
2596 spin_lock_irq(&tty->ctrl_lock);
2597 put_pid(real_tty->pgrp);
2598 real_tty->pgrp = get_pid(pgrp);
2599 spin_unlock_irq(&tty->ctrl_lock);
2606 * tiocgsid - get session id
2607 * @tty: tty passed by user
2608 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2609 * @p: pointer to returned session id
2611 * Obtain the session id of the tty. If there is no session
2614 * Locking: none. Reference to current->signal->tty is safe.
2617 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2620 * (tty == real_tty) is a cheap way of
2621 * testing if the tty is NOT a master pty.
2623 if (tty == real_tty && current->signal->tty != real_tty)
2625 if (!real_tty->session)
2627 return put_user(pid_vnr(real_tty->session), p);
2631 * tiocsetd - set line discipline
2633 * @p: pointer to user data
2635 * Set the line discipline according to user request.
2637 * Locking: see tty_set_ldisc, this function is just a helper
2640 static int tiocsetd(struct tty_struct *tty, int __user *p)
2645 if (get_user(ldisc, p))
2648 ret = tty_set_ldisc(tty, ldisc);
2654 * tiocgetd - get line discipline
2656 * @p: pointer to user data
2658 * Retrieves the line discipline id directly from the ldisc.
2660 * Locking: waits for ldisc reference (in case the line discipline
2661 * is changing or the tty is being hungup)
2664 static int tiocgetd(struct tty_struct *tty, int __user *p)
2666 struct tty_ldisc *ld;
2669 ld = tty_ldisc_ref_wait(tty);
2670 ret = put_user(ld->ops->num, p);
2671 tty_ldisc_deref(ld);
2676 * send_break - performed time break
2677 * @tty: device to break on
2678 * @duration: timeout in mS
2680 * Perform a timed break on hardware that lacks its own driver level
2681 * timed break functionality.
2684 * atomic_write_lock serializes
2688 static int send_break(struct tty_struct *tty, unsigned int duration)
2692 if (tty->ops->break_ctl == NULL)
2695 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2696 retval = tty->ops->break_ctl(tty, duration);
2698 /* Do the work ourselves */
2699 if (tty_write_lock(tty, 0) < 0)
2701 retval = tty->ops->break_ctl(tty, -1);
2704 if (!signal_pending(current))
2705 msleep_interruptible(duration);
2706 retval = tty->ops->break_ctl(tty, 0);
2708 tty_write_unlock(tty);
2709 if (signal_pending(current))
2716 * tty_tiocmget - get modem status
2718 * @file: user file pointer
2719 * @p: pointer to result
2721 * Obtain the modem status bits from the tty driver if the feature
2722 * is supported. Return -EINVAL if it is not available.
2724 * Locking: none (up to the driver)
2727 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2729 int retval = -EINVAL;
2731 if (tty->ops->tiocmget) {
2732 retval = tty->ops->tiocmget(tty);
2735 retval = put_user(retval, p);
2741 * tty_tiocmset - set modem status
2743 * @cmd: command - clear bits, set bits or set all
2744 * @p: pointer to desired bits
2746 * Set the modem status bits from the tty driver if the feature
2747 * is supported. Return -EINVAL if it is not available.
2749 * Locking: none (up to the driver)
2752 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2756 unsigned int set, clear, val;
2758 if (tty->ops->tiocmset == NULL)
2761 retval = get_user(val, p);
2777 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2778 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2779 return tty->ops->tiocmset(tty, set, clear);
2782 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2784 int retval = -EINVAL;
2785 struct serial_icounter_struct icount;
2786 memset(&icount, 0, sizeof(icount));
2787 if (tty->ops->get_icount)
2788 retval = tty->ops->get_icount(tty, &icount);
2791 if (copy_to_user(arg, &icount, sizeof(icount)))
2796 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2798 static DEFINE_RATELIMIT_STATE(depr_flags,
2799 DEFAULT_RATELIMIT_INTERVAL,
2800 DEFAULT_RATELIMIT_BURST);
2801 char comm[TASK_COMM_LEN];
2804 if (get_user(flags, &ss->flags))
2807 flags &= ASYNC_DEPRECATED;
2809 if (flags && __ratelimit(&depr_flags))
2810 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2811 __func__, get_task_comm(comm, current), flags);
2815 * if pty, return the slave side (real_tty)
2816 * otherwise, return self
2818 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2820 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2821 tty->driver->subtype == PTY_TYPE_MASTER)
2827 * Split this up, as gcc can choke on it otherwise..
2829 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2831 struct tty_struct *tty = file_tty(file);
2832 struct tty_struct *real_tty;
2833 void __user *p = (void __user *)arg;
2835 struct tty_ldisc *ld;
2837 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2840 real_tty = tty_pair_get_tty(tty);
2843 * Factor out some common prep work
2851 retval = tty_check_change(tty);
2854 if (cmd != TIOCCBRK) {
2855 tty_wait_until_sent(tty, 0);
2856 if (signal_pending(current))
2867 return tiocsti(tty, p);
2869 return tiocgwinsz(real_tty, p);
2871 return tiocswinsz(real_tty, p);
2873 return real_tty != tty ? -EINVAL : tioccons(file);
2875 return fionbio(file, p);
2877 set_bit(TTY_EXCLUSIVE, &tty->flags);
2880 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2884 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2885 return put_user(excl, (int __user *)p);
2888 if (current->signal->tty != tty)
2893 return tiocsctty(real_tty, file, arg);
2895 return tiocgpgrp(tty, real_tty, p);
2897 return tiocspgrp(tty, real_tty, p);
2899 return tiocgsid(tty, real_tty, p);
2901 return tiocgetd(tty, p);
2903 return tiocsetd(tty, p);
2905 if (!capable(CAP_SYS_ADMIN))
2911 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2912 return put_user(ret, (unsigned int __user *)p);
2917 case TIOCSBRK: /* Turn break on, unconditionally */
2918 if (tty->ops->break_ctl)
2919 return tty->ops->break_ctl(tty, -1);
2921 case TIOCCBRK: /* Turn break off, unconditionally */
2922 if (tty->ops->break_ctl)
2923 return tty->ops->break_ctl(tty, 0);
2925 case TCSBRK: /* SVID version: non-zero arg --> no break */
2926 /* non-zero arg means wait for all output data
2927 * to be sent (performed above) but don't send break.
2928 * This is used by the tcdrain() termios function.
2931 return send_break(tty, 250);
2933 case TCSBRKP: /* support for POSIX tcsendbreak() */
2934 return send_break(tty, arg ? arg*100 : 250);
2937 return tty_tiocmget(tty, p);
2941 return tty_tiocmset(tty, cmd, p);
2943 retval = tty_tiocgicount(tty, p);
2944 /* For the moment allow fall through to the old method */
2945 if (retval != -EINVAL)
2952 /* flush tty buffer and allow ldisc to process ioctl */
2953 tty_buffer_flush(tty, NULL);
2958 tty_warn_deprecated_flags(p);
2961 if (tty->ops->ioctl) {
2962 retval = tty->ops->ioctl(tty, cmd, arg);
2963 if (retval != -ENOIOCTLCMD)
2966 ld = tty_ldisc_ref_wait(tty);
2968 if (ld->ops->ioctl) {
2969 retval = ld->ops->ioctl(tty, file, cmd, arg);
2970 if (retval == -ENOIOCTLCMD)
2973 tty_ldisc_deref(ld);
2977 #ifdef CONFIG_COMPAT
2978 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2981 struct tty_struct *tty = file_tty(file);
2982 struct tty_ldisc *ld;
2983 int retval = -ENOIOCTLCMD;
2985 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2988 if (tty->ops->compat_ioctl) {
2989 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2990 if (retval != -ENOIOCTLCMD)
2994 ld = tty_ldisc_ref_wait(tty);
2995 if (ld->ops->compat_ioctl)
2996 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2998 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2999 tty_ldisc_deref(ld);
3005 static int this_tty(const void *t, struct file *file, unsigned fd)
3007 if (likely(file->f_op->read != tty_read))
3009 return file_tty(file) != t ? 0 : fd + 1;
3013 * This implements the "Secure Attention Key" --- the idea is to
3014 * prevent trojan horses by killing all processes associated with this
3015 * tty when the user hits the "Secure Attention Key". Required for
3016 * super-paranoid applications --- see the Orange Book for more details.
3018 * This code could be nicer; ideally it should send a HUP, wait a few
3019 * seconds, then send a INT, and then a KILL signal. But you then
3020 * have to coordinate with the init process, since all processes associated
3021 * with the current tty must be dead before the new getty is allowed
3024 * Now, if it would be correct ;-/ The current code has a nasty hole -
3025 * it doesn't catch files in flight. We may send the descriptor to ourselves
3026 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3028 * Nasty bug: do_SAK is being called in interrupt context. This can
3029 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3031 void __do_SAK(struct tty_struct *tty)
3036 struct task_struct *g, *p;
3037 struct pid *session;
3042 session = tty->session;
3044 tty_ldisc_flush(tty);
3046 tty_driver_flush_buffer(tty);
3048 read_lock(&tasklist_lock);
3049 /* Kill the entire session */
3050 do_each_pid_task(session, PIDTYPE_SID, p) {
3051 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3052 task_pid_nr(p), p->comm);
3053 send_sig(SIGKILL, p, 1);
3054 } while_each_pid_task(session, PIDTYPE_SID, p);
3056 /* Now kill any processes that happen to have the tty open */
3057 do_each_thread(g, p) {
3058 if (p->signal->tty == tty) {
3059 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3060 task_pid_nr(p), p->comm);
3061 send_sig(SIGKILL, p, 1);
3065 i = iterate_fd(p->files, 0, this_tty, tty);
3067 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3068 task_pid_nr(p), p->comm, i - 1);
3069 force_sig(SIGKILL, p);
3072 } while_each_thread(g, p);
3073 read_unlock(&tasklist_lock);
3077 static void do_SAK_work(struct work_struct *work)
3079 struct tty_struct *tty =
3080 container_of(work, struct tty_struct, SAK_work);
3085 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3086 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3087 * the values which we write to it will be identical to the values which it
3088 * already has. --akpm
3090 void do_SAK(struct tty_struct *tty)
3094 schedule_work(&tty->SAK_work);
3097 EXPORT_SYMBOL(do_SAK);
3099 static int dev_match_devt(struct device *dev, const void *data)
3101 const dev_t *devt = data;
3102 return dev->devt == *devt;
3105 /* Must put_device() after it's unused! */
3106 static struct device *tty_get_device(struct tty_struct *tty)
3108 dev_t devt = tty_devnum(tty);
3109 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3116 * This subroutine allocates and initializes a tty structure.
3118 * Locking: none - tty in question is not exposed at this point
3121 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3123 struct tty_struct *tty;
3125 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3129 kref_init(&tty->kref);
3130 tty->magic = TTY_MAGIC;
3131 tty_ldisc_init(tty);
3132 tty->session = NULL;
3134 mutex_init(&tty->legacy_mutex);
3135 mutex_init(&tty->throttle_mutex);
3136 init_rwsem(&tty->termios_rwsem);
3137 mutex_init(&tty->winsize_mutex);
3138 init_ldsem(&tty->ldisc_sem);
3139 init_waitqueue_head(&tty->write_wait);
3140 init_waitqueue_head(&tty->read_wait);
3141 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3142 mutex_init(&tty->atomic_write_lock);
3143 spin_lock_init(&tty->ctrl_lock);
3144 spin_lock_init(&tty->flow_lock);
3145 INIT_LIST_HEAD(&tty->tty_files);
3146 INIT_WORK(&tty->SAK_work, do_SAK_work);
3148 tty->driver = driver;
3149 tty->ops = driver->ops;
3151 tty_line_name(driver, idx, tty->name);
3152 tty->dev = tty_get_device(tty);
3158 * tty_put_char - write one character to a tty
3162 * Write one byte to the tty using the provided put_char method
3163 * if present. Returns the number of characters successfully output.
3165 * Note: the specific put_char operation in the driver layer may go
3166 * away soon. Don't call it directly, use this method
3169 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3171 if (tty->ops->put_char)
3172 return tty->ops->put_char(tty, ch);
3173 return tty->ops->write(tty, &ch, 1);
3175 EXPORT_SYMBOL_GPL(tty_put_char);
3177 struct class *tty_class;
3179 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3180 unsigned int index, unsigned int count)
3184 /* init here, since reused cdevs cause crashes */
3185 driver->cdevs[index] = cdev_alloc();
3186 if (!driver->cdevs[index])
3188 driver->cdevs[index]->ops = &tty_fops;
3189 driver->cdevs[index]->owner = driver->owner;
3190 err = cdev_add(driver->cdevs[index], dev, count);
3192 kobject_put(&driver->cdevs[index]->kobj);
3197 * tty_register_device - register a tty device
3198 * @driver: the tty driver that describes the tty device
3199 * @index: the index in the tty driver for this tty device
3200 * @device: a struct device that is associated with this tty device.
3201 * This field is optional, if there is no known struct device
3202 * for this tty device it can be set to NULL safely.
3204 * Returns a pointer to the struct device for this tty device
3205 * (or ERR_PTR(-EFOO) on error).
3207 * This call is required to be made to register an individual tty device
3208 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3209 * that bit is not set, this function should not be called by a tty
3215 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3216 struct device *device)
3218 return tty_register_device_attr(driver, index, device, NULL, NULL);
3220 EXPORT_SYMBOL(tty_register_device);
3222 static void tty_device_create_release(struct device *dev)
3224 dev_dbg(dev, "releasing...\n");
3229 * tty_register_device_attr - register a tty device
3230 * @driver: the tty driver that describes the tty device
3231 * @index: the index in the tty driver for this tty device
3232 * @device: a struct device that is associated with this tty device.
3233 * This field is optional, if there is no known struct device
3234 * for this tty device it can be set to NULL safely.
3235 * @drvdata: Driver data to be set to device.
3236 * @attr_grp: Attribute group to be set on device.
3238 * Returns a pointer to the struct device for this tty device
3239 * (or ERR_PTR(-EFOO) on error).
3241 * This call is required to be made to register an individual tty device
3242 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3243 * that bit is not set, this function should not be called by a tty
3248 struct device *tty_register_device_attr(struct tty_driver *driver,
3249 unsigned index, struct device *device,
3251 const struct attribute_group **attr_grp)
3254 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3255 struct device *dev = NULL;
3256 int retval = -ENODEV;
3259 if (index >= driver->num) {
3260 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3261 driver->name, index);
3262 return ERR_PTR(-EINVAL);
3265 if (driver->type == TTY_DRIVER_TYPE_PTY)
3266 pty_line_name(driver, index, name);
3268 tty_line_name(driver, index, name);
3270 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3271 retval = tty_cdev_add(driver, devt, index, 1);
3277 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3284 dev->class = tty_class;
3285 dev->parent = device;
3286 dev->release = tty_device_create_release;
3287 dev_set_name(dev, "%s", name);
3288 dev->groups = attr_grp;
3289 dev_set_drvdata(dev, drvdata);
3291 retval = device_register(dev);
3300 cdev_del(driver->cdevs[index]);
3301 driver->cdevs[index] = NULL;
3303 return ERR_PTR(retval);
3305 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3308 * tty_unregister_device - unregister a tty device
3309 * @driver: the tty driver that describes the tty device
3310 * @index: the index in the tty driver for this tty device
3312 * If a tty device is registered with a call to tty_register_device() then
3313 * this function must be called when the tty device is gone.
3318 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3320 device_destroy(tty_class,
3321 MKDEV(driver->major, driver->minor_start) + index);
3322 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3323 cdev_del(driver->cdevs[index]);
3324 driver->cdevs[index] = NULL;
3327 EXPORT_SYMBOL(tty_unregister_device);
3330 * __tty_alloc_driver -- allocate tty driver
3331 * @lines: count of lines this driver can handle at most
3332 * @owner: module which is repsonsible for this driver
3333 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3335 * This should not be called directly, some of the provided macros should be
3336 * used instead. Use IS_ERR and friends on @retval.
3338 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3339 unsigned long flags)
3341 struct tty_driver *driver;
3342 unsigned int cdevs = 1;
3345 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3346 return ERR_PTR(-EINVAL);
3348 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3350 return ERR_PTR(-ENOMEM);
3352 kref_init(&driver->kref);
3353 driver->magic = TTY_DRIVER_MAGIC;
3354 driver->num = lines;
3355 driver->owner = owner;
3356 driver->flags = flags;
3358 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3359 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3361 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3363 if (!driver->ttys || !driver->termios) {
3369 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3370 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3372 if (!driver->ports) {
3379 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3380 if (!driver->cdevs) {
3387 kfree(driver->ports);
3388 kfree(driver->ttys);
3389 kfree(driver->termios);
3390 kfree(driver->cdevs);
3392 return ERR_PTR(err);
3394 EXPORT_SYMBOL(__tty_alloc_driver);
3396 static void destruct_tty_driver(struct kref *kref)
3398 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3400 struct ktermios *tp;
3402 if (driver->flags & TTY_DRIVER_INSTALLED) {
3404 * Free the termios and termios_locked structures because
3405 * we don't want to get memory leaks when modular tty
3406 * drivers are removed from the kernel.
3408 for (i = 0; i < driver->num; i++) {
3409 tp = driver->termios[i];
3411 driver->termios[i] = NULL;
3414 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3415 tty_unregister_device(driver, i);
3417 proc_tty_unregister_driver(driver);
3418 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3419 cdev_del(driver->cdevs[0]);
3421 kfree(driver->cdevs);
3422 kfree(driver->ports);
3423 kfree(driver->termios);
3424 kfree(driver->ttys);
3428 void tty_driver_kref_put(struct tty_driver *driver)
3430 kref_put(&driver->kref, destruct_tty_driver);
3432 EXPORT_SYMBOL(tty_driver_kref_put);
3434 void tty_set_operations(struct tty_driver *driver,
3435 const struct tty_operations *op)
3439 EXPORT_SYMBOL(tty_set_operations);
3441 void put_tty_driver(struct tty_driver *d)
3443 tty_driver_kref_put(d);
3445 EXPORT_SYMBOL(put_tty_driver);
3448 * Called by a tty driver to register itself.
3450 int tty_register_driver(struct tty_driver *driver)
3457 if (!driver->major) {
3458 error = alloc_chrdev_region(&dev, driver->minor_start,
3459 driver->num, driver->name);
3461 driver->major = MAJOR(dev);
3462 driver->minor_start = MINOR(dev);
3465 dev = MKDEV(driver->major, driver->minor_start);
3466 error = register_chrdev_region(dev, driver->num, driver->name);
3471 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3472 error = tty_cdev_add(driver, dev, 0, driver->num);
3474 goto err_unreg_char;
3477 mutex_lock(&tty_mutex);
3478 list_add(&driver->tty_drivers, &tty_drivers);
3479 mutex_unlock(&tty_mutex);
3481 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3482 for (i = 0; i < driver->num; i++) {
3483 d = tty_register_device(driver, i, NULL);
3486 goto err_unreg_devs;
3490 proc_tty_register_driver(driver);
3491 driver->flags |= TTY_DRIVER_INSTALLED;
3495 for (i--; i >= 0; i--)
3496 tty_unregister_device(driver, i);
3498 mutex_lock(&tty_mutex);
3499 list_del(&driver->tty_drivers);
3500 mutex_unlock(&tty_mutex);
3503 unregister_chrdev_region(dev, driver->num);
3507 EXPORT_SYMBOL(tty_register_driver);
3510 * Called by a tty driver to unregister itself.
3512 int tty_unregister_driver(struct tty_driver *driver)
3516 if (driver->refcount)
3519 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3521 mutex_lock(&tty_mutex);
3522 list_del(&driver->tty_drivers);
3523 mutex_unlock(&tty_mutex);
3527 EXPORT_SYMBOL(tty_unregister_driver);
3529 dev_t tty_devnum(struct tty_struct *tty)
3531 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3533 EXPORT_SYMBOL(tty_devnum);
3535 void tty_default_fops(struct file_operations *fops)
3541 * Initialize the console device. This is called *early*, so
3542 * we can't necessarily depend on lots of kernel help here.
3543 * Just do some early initializations, and do the complex setup
3546 void __init console_init(void)
3550 /* Setup the default TTY line discipline. */
3554 * set up the console device so that later boot sequences can
3555 * inform about problems etc..
3557 call = __con_initcall_start;
3558 while (call < __con_initcall_end) {
3564 static char *tty_devnode(struct device *dev, umode_t *mode)
3568 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3569 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3574 static int __init tty_class_init(void)
3576 tty_class = class_create(THIS_MODULE, "tty");
3577 if (IS_ERR(tty_class))
3578 return PTR_ERR(tty_class);
3579 tty_class->devnode = tty_devnode;
3583 postcore_initcall(tty_class_init);
3585 /* 3/2004 jmc: why do these devices exist? */
3586 static struct cdev tty_cdev, console_cdev;
3588 static ssize_t show_cons_active(struct device *dev,
3589 struct device_attribute *attr, char *buf)
3591 struct console *cs[16];
3597 for_each_console(c) {
3602 if ((c->flags & CON_ENABLED) == 0)
3605 if (i >= ARRAY_SIZE(cs))
3609 int index = cs[i]->index;
3610 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3612 /* don't resolve tty0 as some programs depend on it */
3613 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3614 count += tty_line_name(drv, index, buf + count);
3616 count += sprintf(buf + count, "%s%d",
3617 cs[i]->name, cs[i]->index);
3619 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3625 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3627 static struct attribute *cons_dev_attrs[] = {
3628 &dev_attr_active.attr,
3632 ATTRIBUTE_GROUPS(cons_dev);
3634 static struct device *consdev;
3636 void console_sysfs_notify(void)
3639 sysfs_notify(&consdev->kobj, NULL, "active");
3643 * Ok, now we can initialize the rest of the tty devices and can count
3644 * on memory allocations, interrupts etc..
3646 int __init tty_init(void)
3648 cdev_init(&tty_cdev, &tty_fops);
3649 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3650 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3651 panic("Couldn't register /dev/tty driver\n");
3652 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3654 cdev_init(&console_cdev, &console_fops);
3655 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3656 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3657 panic("Couldn't register /dev/console driver\n");
3658 consdev = device_create_with_groups(tty_class, NULL,
3659 MKDEV(TTYAUX_MAJOR, 1), NULL,
3660 cons_dev_groups, "console");
3661 if (IS_ERR(consdev))
3665 vty_init(&console_fops);