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
110 #define TTY_PARANOIA_CHECK 1
111 #define CHECK_TTY_COUNT 1
113 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
114 .c_iflag = ICRNL | IXON,
115 .c_oflag = OPOST | ONLCR,
116 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
117 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
118 ECHOCTL | ECHOKE | IEXTEN,
124 EXPORT_SYMBOL(tty_std_termios);
126 /* This list gets poked at by procfs and various bits of boot up code. This
127 could do with some rationalisation such as pulling the tty proc function
130 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
132 /* Mutex to protect creating and releasing a tty. This is shared with
133 vt.c for deeply disgusting hack reasons */
134 DEFINE_MUTEX(tty_mutex);
135 EXPORT_SYMBOL(tty_mutex);
137 /* Spinlock to protect the tty->tty_files list */
138 DEFINE_SPINLOCK(tty_files_lock);
140 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
141 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
142 ssize_t redirected_tty_write(struct file *, const char __user *,
144 static unsigned int tty_poll(struct file *, poll_table *);
145 static int tty_open(struct inode *, struct file *);
146 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
148 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
151 #define tty_compat_ioctl NULL
153 static int __tty_fasync(int fd, struct file *filp, int on);
154 static int tty_fasync(int fd, struct file *filp, int on);
155 static void release_tty(struct tty_struct *tty, int idx);
158 * free_tty_struct - free a disused tty
159 * @tty: tty struct to free
161 * Free the write buffers, tty queue and tty memory itself.
163 * Locking: none. Must be called after tty is definitely unused
166 void free_tty_struct(struct tty_struct *tty)
171 put_device(tty->dev);
172 kfree(tty->write_buf);
173 tty->magic = 0xDEADDEAD;
177 static inline struct tty_struct *file_tty(struct file *file)
179 return ((struct tty_file_private *)file->private_data)->tty;
182 int tty_alloc_file(struct file *file)
184 struct tty_file_private *priv;
186 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
190 file->private_data = priv;
195 /* Associate a new file with the tty structure */
196 void tty_add_file(struct tty_struct *tty, struct file *file)
198 struct tty_file_private *priv = file->private_data;
203 spin_lock(&tty_files_lock);
204 list_add(&priv->list, &tty->tty_files);
205 spin_unlock(&tty_files_lock);
209 * tty_free_file - free file->private_data
211 * This shall be used only for fail path handling when tty_add_file was not
214 void tty_free_file(struct file *file)
216 struct tty_file_private *priv = file->private_data;
218 file->private_data = NULL;
222 /* Delete file from its tty */
223 static void tty_del_file(struct file *file)
225 struct tty_file_private *priv = file->private_data;
227 spin_lock(&tty_files_lock);
228 list_del(&priv->list);
229 spin_unlock(&tty_files_lock);
234 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
237 * tty_name - return tty naming
238 * @tty: tty structure
239 * @buf: buffer for output
241 * Convert a tty structure into a name. The name reflects the kernel
242 * naming policy and if udev is in use may not reflect user space
247 char *tty_name(struct tty_struct *tty, char *buf)
249 if (!tty) /* Hmm. NULL pointer. That's fun. */
250 strcpy(buf, "NULL tty");
252 strcpy(buf, tty->name);
256 EXPORT_SYMBOL(tty_name);
258 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
261 #ifdef TTY_PARANOIA_CHECK
264 "null TTY for (%d:%d) in %s\n",
265 imajor(inode), iminor(inode), routine);
268 if (tty->magic != TTY_MAGIC) {
270 "bad magic number for tty struct (%d:%d) in %s\n",
271 imajor(inode), iminor(inode), routine);
278 static int check_tty_count(struct tty_struct *tty, const char *routine)
280 #ifdef CHECK_TTY_COUNT
284 spin_lock(&tty_files_lock);
285 list_for_each(p, &tty->tty_files) {
288 spin_unlock(&tty_files_lock);
289 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
290 tty->driver->subtype == PTY_TYPE_SLAVE &&
291 tty->link && tty->link->count)
293 if (tty->count != count) {
294 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
295 "!= #fd's(%d) in %s\n",
296 tty->name, tty->count, count, routine);
304 * get_tty_driver - find device of a tty
305 * @dev_t: device identifier
306 * @index: returns the index of the tty
308 * This routine returns a tty driver structure, given a device number
309 * and also passes back the index number.
311 * Locking: caller must hold tty_mutex
314 static struct tty_driver *get_tty_driver(dev_t device, int *index)
316 struct tty_driver *p;
318 list_for_each_entry(p, &tty_drivers, tty_drivers) {
319 dev_t base = MKDEV(p->major, p->minor_start);
320 if (device < base || device >= base + p->num)
322 *index = device - base;
323 return tty_driver_kref_get(p);
328 #ifdef CONFIG_CONSOLE_POLL
331 * tty_find_polling_driver - find device of a polled tty
332 * @name: name string to match
333 * @line: pointer to resulting tty line nr
335 * This routine returns a tty driver structure, given a name
336 * and the condition that the tty driver is capable of polled
339 struct tty_driver *tty_find_polling_driver(char *name, int *line)
341 struct tty_driver *p, *res = NULL;
346 for (str = name; *str; str++)
347 if ((*str >= '0' && *str <= '9') || *str == ',')
353 tty_line = simple_strtoul(str, &str, 10);
355 mutex_lock(&tty_mutex);
356 /* Search through the tty devices to look for a match */
357 list_for_each_entry(p, &tty_drivers, tty_drivers) {
358 if (strncmp(name, p->name, len) != 0)
366 if (tty_line >= 0 && tty_line < p->num && p->ops &&
367 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
368 res = tty_driver_kref_get(p);
373 mutex_unlock(&tty_mutex);
377 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
381 * tty_check_change - check for POSIX terminal changes
384 * If we try to write to, or set the state of, a terminal and we're
385 * not in the foreground, send a SIGTTOU. If the signal is blocked or
386 * ignored, go ahead and perform the operation. (POSIX 7.2)
391 int tty_check_change(struct tty_struct *tty)
396 if (current->signal->tty != tty)
399 spin_lock_irqsave(&tty->ctrl_lock, flags);
402 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
405 if (task_pgrp(current) == tty->pgrp)
407 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
408 if (is_ignored(SIGTTOU))
410 if (is_current_pgrp_orphaned()) {
414 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
415 set_thread_flag(TIF_SIGPENDING);
420 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
424 EXPORT_SYMBOL(tty_check_change);
426 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
427 size_t count, loff_t *ppos)
432 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
433 size_t count, loff_t *ppos)
438 /* No kernel lock held - none needed ;) */
439 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
441 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
444 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
447 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
450 static long hung_up_tty_compat_ioctl(struct file *file,
451 unsigned int cmd, unsigned long arg)
453 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
456 static const struct file_operations tty_fops = {
461 .unlocked_ioctl = tty_ioctl,
462 .compat_ioctl = tty_compat_ioctl,
464 .release = tty_release,
465 .fasync = tty_fasync,
468 static const struct file_operations console_fops = {
471 .write = redirected_tty_write,
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 hung_up_tty_fops = {
482 .read = hung_up_tty_read,
483 .write = hung_up_tty_write,
484 .poll = hung_up_tty_poll,
485 .unlocked_ioctl = hung_up_tty_ioctl,
486 .compat_ioctl = hung_up_tty_compat_ioctl,
487 .release = tty_release,
490 static DEFINE_SPINLOCK(redirect_lock);
491 static struct file *redirect;
494 void proc_clear_tty(struct task_struct *p)
497 struct tty_struct *tty;
498 spin_lock_irqsave(&p->sighand->siglock, flags);
499 tty = p->signal->tty;
500 p->signal->tty = NULL;
501 spin_unlock_irqrestore(&p->sighand->siglock, flags);
506 * proc_set_tty - set the controlling terminal
508 * Only callable by the session leader and only if it does not already have
509 * a controlling terminal.
511 * Caller must hold: a readlock on tasklist_lock
514 static void __proc_set_tty(struct tty_struct *tty)
518 /* We should not have a session or pgrp to put here but.... */
519 spin_lock_irqsave(&tty->ctrl_lock, flags);
520 put_pid(tty->session);
522 tty->pgrp = get_pid(task_pgrp(current));
523 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
524 tty->session = get_pid(task_session(current));
525 if (current->signal->tty) {
526 printk(KERN_DEBUG "tty not NULL!!\n");
527 tty_kref_put(current->signal->tty);
529 put_pid(current->signal->tty_old_pgrp);
530 current->signal->tty = tty_kref_get(tty);
531 current->signal->tty_old_pgrp = NULL;
534 static void proc_set_tty(struct tty_struct *tty)
536 spin_lock_irq(¤t->sighand->siglock);
538 spin_unlock_irq(¤t->sighand->siglock);
541 struct tty_struct *get_current_tty(void)
543 struct tty_struct *tty;
546 spin_lock_irqsave(¤t->sighand->siglock, flags);
547 tty = tty_kref_get(current->signal->tty);
548 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
551 EXPORT_SYMBOL_GPL(get_current_tty);
553 static void session_clear_tty(struct pid *session)
555 struct task_struct *p;
556 do_each_pid_task(session, PIDTYPE_SID, p) {
558 } while_each_pid_task(session, PIDTYPE_SID, p);
562 * tty_wakeup - request more data
565 * Internal and external helper for wakeups of tty. This function
566 * informs the line discipline if present that the driver is ready
567 * to receive more output data.
570 void tty_wakeup(struct tty_struct *tty)
572 struct tty_ldisc *ld;
574 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
575 ld = tty_ldisc_ref(tty);
577 if (ld->ops->write_wakeup)
578 ld->ops->write_wakeup(tty);
582 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
585 EXPORT_SYMBOL_GPL(tty_wakeup);
588 * tty_signal_session_leader - sends SIGHUP to session leader
589 * @tty controlling tty
590 * @exit_session if non-zero, signal all foreground group processes
592 * Send SIGHUP and SIGCONT to the session leader and its process group.
593 * Optionally, signal all processes in the foreground process group.
595 * Returns the number of processes in the session with this tty
596 * as their controlling terminal. This value is used to drop
597 * tty references for those processes.
599 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
601 struct task_struct *p;
603 struct pid *tty_pgrp = NULL;
605 read_lock(&tasklist_lock);
607 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
608 spin_lock_irq(&p->sighand->siglock);
609 if (p->signal->tty == tty) {
610 p->signal->tty = NULL;
611 /* We defer the dereferences outside fo
615 if (!p->signal->leader) {
616 spin_unlock_irq(&p->sighand->siglock);
619 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
620 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
621 put_pid(p->signal->tty_old_pgrp); /* A noop */
622 spin_lock(&tty->ctrl_lock);
623 tty_pgrp = get_pid(tty->pgrp);
625 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
626 spin_unlock(&tty->ctrl_lock);
627 spin_unlock_irq(&p->sighand->siglock);
628 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
630 read_unlock(&tasklist_lock);
634 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
642 * __tty_hangup - actual handler for hangup events
645 * This can be called by a "kworker" kernel thread. That is process
646 * synchronous but doesn't hold any locks, so we need to make sure we
647 * have the appropriate locks for what we're doing.
649 * The hangup event clears any pending redirections onto the hung up
650 * device. It ensures future writes will error and it does the needed
651 * line discipline hangup and signal delivery. The tty object itself
656 * redirect lock for undoing redirection
657 * file list lock for manipulating list of ttys
658 * tty_ldiscs_lock from called functions
659 * termios_rwsem resetting termios data
660 * tasklist_lock to walk task list for hangup event
661 * ->siglock to protect ->signal/->sighand
663 static void __tty_hangup(struct tty_struct *tty, int exit_session)
665 struct file *cons_filp = NULL;
666 struct file *filp, *f = NULL;
667 struct tty_file_private *priv;
668 int closecount = 0, n;
675 spin_lock(&redirect_lock);
676 if (redirect && file_tty(redirect) == tty) {
680 spin_unlock(&redirect_lock);
684 if (test_bit(TTY_HUPPED, &tty->flags)) {
689 /* some functions below drop BTM, so we need this bit */
690 set_bit(TTY_HUPPING, &tty->flags);
692 /* inuse_filps is protected by the single tty lock,
693 this really needs to change if we want to flush the
694 workqueue with the lock held */
695 check_tty_count(tty, "tty_hangup");
697 spin_lock(&tty_files_lock);
698 /* This breaks for file handles being sent over AF_UNIX sockets ? */
699 list_for_each_entry(priv, &tty->tty_files, list) {
701 if (filp->f_op->write == redirected_tty_write)
703 if (filp->f_op->write != tty_write)
706 __tty_fasync(-1, filp, 0); /* can't block */
707 filp->f_op = &hung_up_tty_fops;
709 spin_unlock(&tty_files_lock);
711 refs = tty_signal_session_leader(tty, exit_session);
712 /* Account for the p->signal references we killed */
717 * it drops BTM and thus races with reopen
718 * we protect the race by TTY_HUPPING
720 tty_ldisc_hangup(tty);
722 spin_lock_irq(&tty->ctrl_lock);
723 clear_bit(TTY_THROTTLED, &tty->flags);
724 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
725 put_pid(tty->session);
729 tty->ctrl_status = 0;
730 spin_unlock_irq(&tty->ctrl_lock);
733 * If one of the devices matches a console pointer, we
734 * cannot just call hangup() because that will cause
735 * tty->count and state->count to go out of sync.
736 * So we just call close() the right number of times.
740 for (n = 0; n < closecount; n++)
741 tty->ops->close(tty, cons_filp);
742 } else if (tty->ops->hangup)
743 tty->ops->hangup(tty);
745 * We don't want to have driver/ldisc interactions beyond
746 * the ones we did here. The driver layer expects no
747 * calls after ->hangup() from the ldisc side. However we
748 * can't yet guarantee all that.
750 set_bit(TTY_HUPPED, &tty->flags);
751 clear_bit(TTY_HUPPING, &tty->flags);
759 static void do_tty_hangup(struct work_struct *work)
761 struct tty_struct *tty =
762 container_of(work, struct tty_struct, hangup_work);
764 __tty_hangup(tty, 0);
768 * tty_hangup - trigger a hangup event
769 * @tty: tty to hangup
771 * A carrier loss (virtual or otherwise) has occurred on this like
772 * schedule a hangup sequence to run after this event.
775 void tty_hangup(struct tty_struct *tty)
777 #ifdef TTY_DEBUG_HANGUP
779 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
781 schedule_work(&tty->hangup_work);
784 EXPORT_SYMBOL(tty_hangup);
787 * tty_vhangup - process vhangup
788 * @tty: tty to hangup
790 * The user has asked via system call for the terminal to be hung up.
791 * We do this synchronously so that when the syscall returns the process
792 * is complete. That guarantee is necessary for security reasons.
795 void tty_vhangup(struct tty_struct *tty)
797 #ifdef TTY_DEBUG_HANGUP
800 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
802 __tty_hangup(tty, 0);
805 EXPORT_SYMBOL(tty_vhangup);
809 * tty_vhangup_self - process vhangup for own ctty
811 * Perform a vhangup on the current controlling tty
814 void tty_vhangup_self(void)
816 struct tty_struct *tty;
818 tty = get_current_tty();
826 * tty_vhangup_session - hangup session leader exit
827 * @tty: tty to hangup
829 * The session leader is exiting and hanging up its controlling terminal.
830 * Every process in the foreground process group is signalled SIGHUP.
832 * We do this synchronously so that when the syscall returns the process
833 * is complete. That guarantee is necessary for security reasons.
836 static void tty_vhangup_session(struct tty_struct *tty)
838 #ifdef TTY_DEBUG_HANGUP
841 printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty, buf));
843 __tty_hangup(tty, 1);
847 * tty_hung_up_p - was tty hung up
848 * @filp: file pointer of tty
850 * Return true if the tty has been subject to a vhangup or a carrier
854 int tty_hung_up_p(struct file *filp)
856 return (filp->f_op == &hung_up_tty_fops);
859 EXPORT_SYMBOL(tty_hung_up_p);
862 * disassociate_ctty - disconnect controlling tty
863 * @on_exit: true if exiting so need to "hang up" the session
865 * This function is typically called only by the session leader, when
866 * it wants to disassociate itself from its controlling tty.
868 * It performs the following functions:
869 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
870 * (2) Clears the tty from being controlling the session
871 * (3) Clears the controlling tty for all processes in the
874 * The argument on_exit is set to 1 if called when a process is
875 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
878 * BTM is taken for hysterical raisins, and held when
879 * called from no_tty().
880 * tty_mutex is taken to protect tty
881 * ->siglock is taken to protect ->signal/->sighand
882 * tasklist_lock is taken to walk process list for sessions
883 * ->siglock is taken to protect ->signal/->sighand
886 void disassociate_ctty(int on_exit)
888 struct tty_struct *tty;
890 if (!current->signal->leader)
893 tty = get_current_tty();
895 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
896 tty_vhangup_session(tty);
898 struct pid *tty_pgrp = tty_get_pgrp(tty);
900 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
902 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
908 } else if (on_exit) {
909 struct pid *old_pgrp;
910 spin_lock_irq(¤t->sighand->siglock);
911 old_pgrp = current->signal->tty_old_pgrp;
912 current->signal->tty_old_pgrp = NULL;
913 spin_unlock_irq(¤t->sighand->siglock);
915 kill_pgrp(old_pgrp, SIGHUP, on_exit);
916 kill_pgrp(old_pgrp, SIGCONT, on_exit);
922 spin_lock_irq(¤t->sighand->siglock);
923 put_pid(current->signal->tty_old_pgrp);
924 current->signal->tty_old_pgrp = NULL;
926 tty = tty_kref_get(current->signal->tty);
929 spin_lock_irqsave(&tty->ctrl_lock, flags);
930 put_pid(tty->session);
934 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
937 #ifdef TTY_DEBUG_HANGUP
938 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
943 spin_unlock_irq(¤t->sighand->siglock);
944 /* Now clear signal->tty under the lock */
945 read_lock(&tasklist_lock);
946 session_clear_tty(task_session(current));
947 read_unlock(&tasklist_lock);
952 * no_tty - Ensure the current process does not have a controlling tty
956 /* FIXME: Review locking here. The tty_lock never covered any race
957 between a new association and proc_clear_tty but possible we need
958 to protect against this anyway */
959 struct task_struct *tsk = current;
960 disassociate_ctty(0);
966 * stop_tty - propagate flow control
969 * Perform flow control to the driver. May be called
970 * on an already stopped device and will not re-call the driver
973 * This functionality is used by both the line disciplines for
974 * halting incoming flow and by the driver. It may therefore be
975 * called from any context, may be under the tty atomic_write_lock
982 void __stop_tty(struct tty_struct *tty)
988 (tty->ops->stop)(tty);
991 void stop_tty(struct tty_struct *tty)
995 spin_lock_irqsave(&tty->flow_lock, flags);
997 spin_unlock_irqrestore(&tty->flow_lock, flags);
999 EXPORT_SYMBOL(stop_tty);
1002 * start_tty - propagate flow control
1003 * @tty: tty to start
1005 * Start a tty that has been stopped if at all possible. If this
1006 * tty was previous stopped and is now being started, the driver
1007 * start method is invoked and the line discipline woken.
1013 void __start_tty(struct tty_struct *tty)
1015 if (!tty->stopped || tty->flow_stopped)
1018 if (tty->ops->start)
1019 (tty->ops->start)(tty);
1023 void start_tty(struct tty_struct *tty)
1025 unsigned long flags;
1027 spin_lock_irqsave(&tty->flow_lock, flags);
1029 spin_unlock_irqrestore(&tty->flow_lock, flags);
1031 EXPORT_SYMBOL(start_tty);
1033 /* We limit tty time update visibility to every 8 seconds or so. */
1034 static void tty_update_time(struct timespec *time)
1036 unsigned long sec = get_seconds() & ~7;
1037 if ((long)(sec - time->tv_sec) > 0)
1042 * tty_read - read method for tty device files
1043 * @file: pointer to tty file
1045 * @count: size of user buffer
1048 * Perform the read system call function on this terminal device. Checks
1049 * for hung up devices before calling the line discipline method.
1052 * Locks the line discipline internally while needed. Multiple
1053 * read calls may be outstanding in parallel.
1056 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1060 struct inode *inode = file_inode(file);
1061 struct tty_struct *tty = file_tty(file);
1062 struct tty_ldisc *ld;
1064 if (tty_paranoia_check(tty, inode, "tty_read"))
1066 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1069 /* We want to wait for the line discipline to sort out in this
1071 ld = tty_ldisc_ref_wait(tty);
1073 i = (ld->ops->read)(tty, file, buf, count);
1076 tty_ldisc_deref(ld);
1079 tty_update_time(&inode->i_atime);
1084 static void tty_write_unlock(struct tty_struct *tty)
1086 mutex_unlock(&tty->atomic_write_lock);
1087 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1090 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1092 if (!mutex_trylock(&tty->atomic_write_lock)) {
1095 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1096 return -ERESTARTSYS;
1102 * Split writes up in sane blocksizes to avoid
1103 * denial-of-service type attacks
1105 static inline ssize_t do_tty_write(
1106 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1107 struct tty_struct *tty,
1109 const char __user *buf,
1112 ssize_t ret, written = 0;
1115 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1120 * We chunk up writes into a temporary buffer. This
1121 * simplifies low-level drivers immensely, since they
1122 * don't have locking issues and user mode accesses.
1124 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1127 * The default chunk-size is 2kB, because the NTTY
1128 * layer has problems with bigger chunks. It will
1129 * claim to be able to handle more characters than
1132 * FIXME: This can probably go away now except that 64K chunks
1133 * are too likely to fail unless switched to vmalloc...
1136 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1141 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1142 if (tty->write_cnt < chunk) {
1143 unsigned char *buf_chunk;
1148 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1153 kfree(tty->write_buf);
1154 tty->write_cnt = chunk;
1155 tty->write_buf = buf_chunk;
1158 /* Do the write .. */
1160 size_t size = count;
1164 if (copy_from_user(tty->write_buf, buf, size))
1166 ret = write(tty, file, tty->write_buf, size);
1175 if (signal_pending(current))
1180 tty_update_time(&file_inode(file)->i_mtime);
1184 tty_write_unlock(tty);
1189 * tty_write_message - write a message to a certain tty, not just the console.
1190 * @tty: the destination tty_struct
1191 * @msg: the message to write
1193 * This is used for messages that need to be redirected to a specific tty.
1194 * We don't put it into the syslog queue right now maybe in the future if
1197 * We must still hold the BTM and test the CLOSING flag for the moment.
1200 void tty_write_message(struct tty_struct *tty, char *msg)
1203 mutex_lock(&tty->atomic_write_lock);
1205 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1207 tty->ops->write(tty, msg, strlen(msg));
1210 tty_write_unlock(tty);
1217 * tty_write - write method for tty device file
1218 * @file: tty file pointer
1219 * @buf: user data to write
1220 * @count: bytes to write
1223 * Write data to a tty device via the line discipline.
1226 * Locks the line discipline as required
1227 * Writes to the tty driver are serialized by the atomic_write_lock
1228 * and are then processed in chunks to the device. The line discipline
1229 * write method will not be invoked in parallel for each device.
1232 static ssize_t tty_write(struct file *file, const char __user *buf,
1233 size_t count, loff_t *ppos)
1235 struct tty_struct *tty = file_tty(file);
1236 struct tty_ldisc *ld;
1239 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1241 if (!tty || !tty->ops->write ||
1242 (test_bit(TTY_IO_ERROR, &tty->flags)))
1244 /* Short term debug to catch buggy drivers */
1245 if (tty->ops->write_room == NULL)
1246 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1248 ld = tty_ldisc_ref_wait(tty);
1249 if (!ld->ops->write)
1252 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1253 tty_ldisc_deref(ld);
1257 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1258 size_t count, loff_t *ppos)
1260 struct file *p = NULL;
1262 spin_lock(&redirect_lock);
1264 p = get_file(redirect);
1265 spin_unlock(&redirect_lock);
1269 res = vfs_write(p, buf, count, &p->f_pos);
1273 return tty_write(file, buf, count, ppos);
1277 * tty_send_xchar - send priority character
1279 * Send a high priority character to the tty even if stopped
1281 * Locking: none for xchar method, write ordering for write method.
1284 int tty_send_xchar(struct tty_struct *tty, char ch)
1286 int was_stopped = tty->stopped;
1288 if (tty->ops->send_xchar) {
1289 tty->ops->send_xchar(tty, ch);
1293 if (tty_write_lock(tty, 0) < 0)
1294 return -ERESTARTSYS;
1298 tty->ops->write(tty, &ch, 1);
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 or ERR_PTR() otherwise.
1354 * Locking: tty_mutex must be held. If tty is found, the mutex must
1355 * be held until the 'fast-open' is also done. Will change once we
1356 * have refcounting in the driver and per driver locking
1358 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1359 struct inode *inode, int idx)
1361 if (driver->ops->lookup)
1362 return driver->ops->lookup(driver, inode, idx);
1364 return driver->ttys[idx];
1368 * tty_init_termios - helper for termios setup
1369 * @tty: the tty to set up
1371 * Initialise the termios structures for this tty. Thus runs under
1372 * the tty_mutex currently so we can be relaxed about ordering.
1375 int tty_init_termios(struct tty_struct *tty)
1377 struct ktermios *tp;
1378 int idx = tty->index;
1380 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1381 tty->termios = tty->driver->init_termios;
1383 /* Check for lazy saved data */
1384 tp = tty->driver->termios[idx];
1388 tty->termios = tty->driver->init_termios;
1390 /* Compatibility until drivers always set this */
1391 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1392 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1395 EXPORT_SYMBOL_GPL(tty_init_termios);
1397 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1399 int ret = tty_init_termios(tty);
1403 tty_driver_kref_get(driver);
1405 driver->ttys[tty->index] = tty;
1408 EXPORT_SYMBOL_GPL(tty_standard_install);
1411 * tty_driver_install_tty() - install a tty entry in the driver
1412 * @driver: the driver for the tty
1415 * Install a tty object into the driver tables. The tty->index field
1416 * will be set by the time this is called. This method is responsible
1417 * for ensuring any need additional structures are allocated and
1420 * Locking: tty_mutex for now
1422 static int tty_driver_install_tty(struct tty_driver *driver,
1423 struct tty_struct *tty)
1425 return driver->ops->install ? driver->ops->install(driver, tty) :
1426 tty_standard_install(driver, tty);
1430 * tty_driver_remove_tty() - remove a tty from the driver tables
1431 * @driver: the driver for the tty
1432 * @idx: the minor number
1434 * Remvoe a tty object from the driver tables. The tty->index field
1435 * will be set by the time this is called.
1437 * Locking: tty_mutex for now
1439 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1441 if (driver->ops->remove)
1442 driver->ops->remove(driver, tty);
1444 driver->ttys[tty->index] = NULL;
1448 * tty_reopen() - fast re-open of an open tty
1449 * @tty - the tty to open
1451 * Return 0 on success, -errno on error.
1453 * Locking: tty_mutex must be held from the time the tty was found
1454 * till this open completes.
1456 static int tty_reopen(struct tty_struct *tty)
1458 struct tty_driver *driver = tty->driver;
1460 if (test_bit(TTY_CLOSING, &tty->flags) ||
1461 test_bit(TTY_HUPPING, &tty->flags))
1464 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1465 driver->subtype == PTY_TYPE_MASTER) {
1467 * special case for PTY masters: only one open permitted,
1468 * and the slave side open count is incremented as well.
1477 WARN_ON(!tty->ldisc);
1483 * tty_init_dev - initialise a tty device
1484 * @driver: tty driver we are opening a device on
1485 * @idx: device index
1486 * @ret_tty: returned tty structure
1488 * Prepare a tty device. This may not be a "new" clean device but
1489 * could also be an active device. The pty drivers require special
1490 * handling because of this.
1493 * The function is called under the tty_mutex, which
1494 * protects us from the tty struct or driver itself going away.
1496 * On exit the tty device has the line discipline attached and
1497 * a reference count of 1. If a pair was created for pty/tty use
1498 * and the other was a pty master then it too has a reference count of 1.
1500 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1501 * failed open. The new code protects the open with a mutex, so it's
1502 * really quite straightforward. The mutex locking can probably be
1503 * relaxed for the (most common) case of reopening a tty.
1506 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1508 struct tty_struct *tty;
1512 * First time open is complex, especially for PTY devices.
1513 * This code guarantees that either everything succeeds and the
1514 * TTY is ready for operation, or else the table slots are vacated
1515 * and the allocated memory released. (Except that the termios
1516 * and locked termios may be retained.)
1519 if (!try_module_get(driver->owner))
1520 return ERR_PTR(-ENODEV);
1522 tty = alloc_tty_struct(driver, idx);
1525 goto err_module_put;
1529 retval = tty_driver_install_tty(driver, tty);
1531 goto err_deinit_tty;
1534 tty->port = driver->ports[idx];
1536 WARN_RATELIMIT(!tty->port,
1537 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1538 __func__, tty->driver->name);
1540 tty->port->itty = tty;
1543 * Structures all installed ... call the ldisc open routines.
1544 * If we fail here just call release_tty to clean up. No need
1545 * to decrement the use counts, as release_tty doesn't care.
1547 retval = tty_ldisc_setup(tty, tty->link);
1549 goto err_release_tty;
1550 /* Return the tty locked so that it cannot vanish under the caller */
1555 deinitialize_tty_struct(tty);
1556 free_tty_struct(tty);
1558 module_put(driver->owner);
1559 return ERR_PTR(retval);
1561 /* call the tty release_tty routine to clean out this slot */
1564 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1565 "clearing slot %d\n", idx);
1566 release_tty(tty, idx);
1567 return ERR_PTR(retval);
1570 void tty_free_termios(struct tty_struct *tty)
1572 struct ktermios *tp;
1573 int idx = tty->index;
1575 /* If the port is going to reset then it has no termios to save */
1576 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1579 /* Stash the termios data */
1580 tp = tty->driver->termios[idx];
1582 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1584 pr_warn("tty: no memory to save termios state.\n");
1587 tty->driver->termios[idx] = tp;
1591 EXPORT_SYMBOL(tty_free_termios);
1594 * tty_flush_works - flush all works of a tty
1595 * @tty: tty device to flush works for
1597 * Sync flush all works belonging to @tty.
1599 static void tty_flush_works(struct tty_struct *tty)
1601 flush_work(&tty->SAK_work);
1602 flush_work(&tty->hangup_work);
1606 * release_one_tty - release tty structure memory
1607 * @kref: kref of tty we are obliterating
1609 * Releases memory associated with a tty structure, and clears out the
1610 * driver table slots. This function is called when a device is no longer
1611 * in use. It also gets called when setup of a device fails.
1614 * takes the file list lock internally when working on the list
1615 * of ttys that the driver keeps.
1617 * This method gets called from a work queue so that the driver private
1618 * cleanup ops can sleep (needed for USB at least)
1620 static void release_one_tty(struct work_struct *work)
1622 struct tty_struct *tty =
1623 container_of(work, struct tty_struct, hangup_work);
1624 struct tty_driver *driver = tty->driver;
1625 struct module *owner = driver->owner;
1627 if (tty->ops->cleanup)
1628 tty->ops->cleanup(tty);
1631 tty_driver_kref_put(driver);
1634 spin_lock(&tty_files_lock);
1635 list_del_init(&tty->tty_files);
1636 spin_unlock(&tty_files_lock);
1639 put_pid(tty->session);
1640 free_tty_struct(tty);
1643 static void queue_release_one_tty(struct kref *kref)
1645 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1647 /* The hangup queue is now free so we can reuse it rather than
1648 waste a chunk of memory for each port */
1649 INIT_WORK(&tty->hangup_work, release_one_tty);
1650 schedule_work(&tty->hangup_work);
1654 * tty_kref_put - release a tty kref
1657 * Release a reference to a tty device and if need be let the kref
1658 * layer destruct the object for us
1661 void tty_kref_put(struct tty_struct *tty)
1664 kref_put(&tty->kref, queue_release_one_tty);
1666 EXPORT_SYMBOL(tty_kref_put);
1669 * release_tty - release tty structure memory
1671 * Release both @tty and a possible linked partner (think pty pair),
1672 * and decrement the refcount of the backing module.
1676 * takes the file list lock internally when working on the list
1677 * of ttys that the driver keeps.
1680 static void release_tty(struct tty_struct *tty, int idx)
1682 /* This should always be true but check for the moment */
1683 WARN_ON(tty->index != idx);
1684 WARN_ON(!mutex_is_locked(&tty_mutex));
1685 if (tty->ops->shutdown)
1686 tty->ops->shutdown(tty);
1687 tty_free_termios(tty);
1688 tty_driver_remove_tty(tty->driver, tty);
1689 tty->port->itty = NULL;
1691 tty->link->port->itty = NULL;
1692 cancel_work_sync(&tty->port->buf.work);
1695 tty_kref_put(tty->link);
1700 * tty_release_checks - check a tty before real release
1701 * @tty: tty to check
1702 * @o_tty: link of @tty (if any)
1703 * @idx: index of the tty
1705 * Performs some paranoid checking before true release of the @tty.
1706 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1708 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1711 #ifdef TTY_PARANOIA_CHECK
1712 if (idx < 0 || idx >= tty->driver->num) {
1713 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1714 __func__, tty->name);
1718 /* not much to check for devpts */
1719 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1722 if (tty != tty->driver->ttys[idx]) {
1723 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1724 __func__, idx, tty->name);
1727 if (tty->driver->other) {
1728 if (o_tty != tty->driver->other->ttys[idx]) {
1729 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1730 __func__, idx, tty->name);
1733 if (o_tty->link != tty) {
1734 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1743 * tty_release - vfs callback for close
1744 * @inode: inode of tty
1745 * @filp: file pointer for handle to tty
1747 * Called the last time each file handle is closed that references
1748 * this tty. There may however be several such references.
1751 * Takes bkl. See tty_release_dev
1753 * Even releasing the tty structures is a tricky business.. We have
1754 * to be very careful that the structures are all released at the
1755 * same time, as interrupts might otherwise get the wrong pointers.
1757 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1758 * lead to double frees or releasing memory still in use.
1761 int tty_release(struct inode *inode, struct file *filp)
1763 struct tty_struct *tty = file_tty(filp);
1764 struct tty_struct *o_tty;
1765 int pty_master, tty_closing, o_tty_closing, do_sleep;
1769 if (tty_paranoia_check(tty, inode, __func__))
1773 check_tty_count(tty, __func__);
1775 __tty_fasync(-1, filp, 0);
1778 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1779 tty->driver->subtype == PTY_TYPE_MASTER);
1780 /* Review: parallel close */
1783 if (tty_release_checks(tty, o_tty, idx)) {
1788 #ifdef TTY_DEBUG_HANGUP
1789 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1790 tty_name(tty, buf), tty->count);
1793 if (tty->ops->close)
1794 tty->ops->close(tty, filp);
1798 * Sanity check: if tty->count is going to zero, there shouldn't be
1799 * any waiters on tty->read_wait or tty->write_wait. We test the
1800 * wait queues and kick everyone out _before_ actually starting to
1801 * close. This ensures that we won't block while releasing the tty
1804 * The test for the o_tty closing is necessary, since the master and
1805 * slave sides may close in any order. If the slave side closes out
1806 * first, its count will be one, since the master side holds an open.
1807 * Thus this test wouldn't be triggered at the time the slave closes,
1810 * Note that it's possible for the tty to be opened again while we're
1811 * flushing out waiters. By recalculating the closing flags before
1812 * each iteration we avoid any problems.
1815 /* Guard against races with tty->count changes elsewhere and
1816 opens on /dev/tty */
1818 mutex_lock(&tty_mutex);
1819 tty_lock_pair(tty, o_tty);
1820 tty_closing = tty->count <= 1;
1821 o_tty_closing = o_tty &&
1822 (o_tty->count <= (pty_master ? 1 : 0));
1826 if (waitqueue_active(&tty->read_wait)) {
1827 wake_up_poll(&tty->read_wait, POLLIN);
1830 if (waitqueue_active(&tty->write_wait)) {
1831 wake_up_poll(&tty->write_wait, POLLOUT);
1835 if (o_tty_closing) {
1836 if (waitqueue_active(&o_tty->read_wait)) {
1837 wake_up_poll(&o_tty->read_wait, POLLIN);
1840 if (waitqueue_active(&o_tty->write_wait)) {
1841 wake_up_poll(&o_tty->write_wait, POLLOUT);
1848 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1849 __func__, tty_name(tty, buf));
1850 tty_unlock_pair(tty, o_tty);
1851 mutex_unlock(&tty_mutex);
1856 * The closing flags are now consistent with the open counts on
1857 * both sides, and we've completed the last operation that could
1858 * block, so it's safe to proceed with closing.
1860 * We must *not* drop the tty_mutex until we ensure that a further
1861 * entry into tty_open can not pick up this tty.
1864 if (--o_tty->count < 0) {
1865 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1866 __func__, o_tty->count, tty_name(o_tty, buf));
1870 if (--tty->count < 0) {
1871 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1872 __func__, tty->count, tty_name(tty, buf));
1877 * We've decremented tty->count, so we need to remove this file
1878 * descriptor off the tty->tty_files list; this serves two
1880 * - check_tty_count sees the correct number of file descriptors
1881 * associated with this tty.
1882 * - do_tty_hangup no longer sees this file descriptor as
1883 * something that needs to be handled for hangups.
1888 * Perform some housekeeping before deciding whether to return.
1890 * Set the TTY_CLOSING flag if this was the last open. In the
1891 * case of a pty we may have to wait around for the other side
1892 * to close, and TTY_CLOSING makes sure we can't be reopened.
1895 set_bit(TTY_CLOSING, &tty->flags);
1897 set_bit(TTY_CLOSING, &o_tty->flags);
1900 * If _either_ side is closing, make sure there aren't any
1901 * processes that still think tty or o_tty is their controlling
1904 if (tty_closing || o_tty_closing) {
1905 read_lock(&tasklist_lock);
1906 session_clear_tty(tty->session);
1908 session_clear_tty(o_tty->session);
1909 read_unlock(&tasklist_lock);
1912 mutex_unlock(&tty_mutex);
1913 tty_unlock_pair(tty, o_tty);
1914 /* At this point the TTY_CLOSING flag should ensure a dead tty
1915 cannot be re-opened by a racing opener */
1917 /* check whether both sides are closing ... */
1918 if (!tty_closing || (o_tty && !o_tty_closing))
1921 #ifdef TTY_DEBUG_HANGUP
1922 printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
1925 * Ask the line discipline code to release its structures
1927 tty_ldisc_release(tty, o_tty);
1929 /* Wait for pending work before tty destruction commmences */
1930 tty_flush_works(tty);
1932 tty_flush_works(o_tty);
1934 #ifdef TTY_DEBUG_HANGUP
1935 printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
1938 * The release_tty function takes care of the details of clearing
1939 * the slots and preserving the termios structure. The tty_unlock_pair
1940 * should be safe as we keep a kref while the tty is locked (so the
1941 * unlock never unlocks a freed tty).
1943 mutex_lock(&tty_mutex);
1944 release_tty(tty, idx);
1945 mutex_unlock(&tty_mutex);
1951 * tty_open_current_tty - get tty of current task for open
1952 * @device: device number
1953 * @filp: file pointer to tty
1954 * @return: tty of the current task iff @device is /dev/tty
1956 * We cannot return driver and index like for the other nodes because
1957 * devpts will not work then. It expects inodes to be from devpts FS.
1959 * We need to move to returning a refcounted object from all the lookup
1960 * paths including this one.
1962 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1964 struct tty_struct *tty;
1966 if (device != MKDEV(TTYAUX_MAJOR, 0))
1969 tty = get_current_tty();
1971 return ERR_PTR(-ENXIO);
1973 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1976 /* FIXME: we put a reference and return a TTY! */
1977 /* This is only safe because the caller holds tty_mutex */
1982 * tty_lookup_driver - lookup a tty driver for a given device file
1983 * @device: device number
1984 * @filp: file pointer to tty
1985 * @noctty: set if the device should not become a controlling tty
1986 * @index: index for the device in the @return driver
1987 * @return: driver for this inode (with increased refcount)
1989 * If @return is not erroneous, the caller is responsible to decrement the
1990 * refcount by tty_driver_kref_put.
1992 * Locking: tty_mutex protects get_tty_driver
1994 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1995 int *noctty, int *index)
1997 struct tty_driver *driver;
2001 case MKDEV(TTY_MAJOR, 0): {
2002 extern struct tty_driver *console_driver;
2003 driver = tty_driver_kref_get(console_driver);
2004 *index = fg_console;
2009 case MKDEV(TTYAUX_MAJOR, 1): {
2010 struct tty_driver *console_driver = console_device(index);
2011 if (console_driver) {
2012 driver = tty_driver_kref_get(console_driver);
2014 /* Don't let /dev/console block */
2015 filp->f_flags |= O_NONBLOCK;
2020 return ERR_PTR(-ENODEV);
2023 driver = get_tty_driver(device, index);
2025 return ERR_PTR(-ENODEV);
2032 * tty_open - open a tty device
2033 * @inode: inode of device file
2034 * @filp: file pointer to tty
2036 * tty_open and tty_release keep up the tty count that contains the
2037 * number of opens done on a tty. We cannot use the inode-count, as
2038 * different inodes might point to the same tty.
2040 * Open-counting is needed for pty masters, as well as for keeping
2041 * track of serial lines: DTR is dropped when the last close happens.
2042 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2044 * The termios state of a pty is reset on first open so that
2045 * settings don't persist across reuse.
2047 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2048 * tty->count should protect the rest.
2049 * ->siglock protects ->signal/->sighand
2051 * Note: the tty_unlock/lock cases without a ref are only safe due to
2055 static int tty_open(struct inode *inode, struct file *filp)
2057 struct tty_struct *tty;
2059 struct tty_driver *driver = NULL;
2061 dev_t device = inode->i_rdev;
2062 unsigned saved_flags = filp->f_flags;
2064 nonseekable_open(inode, filp);
2067 retval = tty_alloc_file(filp);
2071 noctty = filp->f_flags & O_NOCTTY;
2075 mutex_lock(&tty_mutex);
2076 /* This is protected by the tty_mutex */
2077 tty = tty_open_current_tty(device, filp);
2079 retval = PTR_ERR(tty);
2082 driver = tty_lookup_driver(device, filp, &noctty, &index);
2083 if (IS_ERR(driver)) {
2084 retval = PTR_ERR(driver);
2088 /* check whether we're reopening an existing tty */
2089 tty = tty_driver_lookup_tty(driver, inode, index);
2091 retval = PTR_ERR(tty);
2098 retval = tty_reopen(tty);
2101 tty = ERR_PTR(retval);
2103 } else /* Returns with the tty_lock held for now */
2104 tty = tty_init_dev(driver, index);
2106 mutex_unlock(&tty_mutex);
2108 tty_driver_kref_put(driver);
2110 retval = PTR_ERR(tty);
2114 tty_add_file(tty, filp);
2116 check_tty_count(tty, __func__);
2117 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2118 tty->driver->subtype == PTY_TYPE_MASTER)
2120 #ifdef TTY_DEBUG_HANGUP
2121 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
2124 retval = tty->ops->open(tty, filp);
2127 filp->f_flags = saved_flags;
2129 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
2130 !capable(CAP_SYS_ADMIN))
2134 #ifdef TTY_DEBUG_HANGUP
2135 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
2138 tty_unlock(tty); /* need to call tty_release without BTM */
2139 tty_release(inode, filp);
2140 if (retval != -ERESTARTSYS)
2143 if (signal_pending(current))
2148 * Need to reset f_op in case a hangup happened.
2150 if (filp->f_op == &hung_up_tty_fops)
2151 filp->f_op = &tty_fops;
2154 clear_bit(TTY_HUPPED, &tty->flags);
2158 mutex_lock(&tty_mutex);
2160 read_lock(&tasklist_lock);
2161 spin_lock_irq(¤t->sighand->siglock);
2163 current->signal->leader &&
2164 !current->signal->tty &&
2165 tty->session == NULL)
2166 __proc_set_tty(tty);
2167 spin_unlock_irq(¤t->sighand->siglock);
2168 read_unlock(&tasklist_lock);
2170 mutex_unlock(&tty_mutex);
2173 mutex_unlock(&tty_mutex);
2174 /* after locks to avoid deadlock */
2175 if (!IS_ERR_OR_NULL(driver))
2176 tty_driver_kref_put(driver);
2178 tty_free_file(filp);
2185 * tty_poll - check tty status
2186 * @filp: file being polled
2187 * @wait: poll wait structures to update
2189 * Call the line discipline polling method to obtain the poll
2190 * status of the device.
2192 * Locking: locks called line discipline but ldisc poll method
2193 * may be re-entered freely by other callers.
2196 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2198 struct tty_struct *tty = file_tty(filp);
2199 struct tty_ldisc *ld;
2202 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2205 ld = tty_ldisc_ref_wait(tty);
2207 ret = (ld->ops->poll)(tty, filp, wait);
2208 tty_ldisc_deref(ld);
2212 static int __tty_fasync(int fd, struct file *filp, int on)
2214 struct tty_struct *tty = file_tty(filp);
2215 struct tty_ldisc *ldisc;
2216 unsigned long flags;
2219 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2222 retval = fasync_helper(fd, filp, on, &tty->fasync);
2226 ldisc = tty_ldisc_ref(tty);
2228 if (ldisc->ops->fasync)
2229 ldisc->ops->fasync(tty, on);
2230 tty_ldisc_deref(ldisc);
2237 spin_lock_irqsave(&tty->ctrl_lock, flags);
2240 type = PIDTYPE_PGID;
2242 pid = task_pid(current);
2246 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2247 __f_setown(filp, pid, type, 0);
2255 static int tty_fasync(int fd, struct file *filp, int on)
2257 struct tty_struct *tty = file_tty(filp);
2261 retval = __tty_fasync(fd, filp, on);
2268 * tiocsti - fake input character
2269 * @tty: tty to fake input into
2270 * @p: pointer to character
2272 * Fake input to a tty device. Does the necessary locking and
2275 * FIXME: does not honour flow control ??
2278 * Called functions take tty_ldiscs_lock
2279 * current->signal->tty check is safe without locks
2281 * FIXME: may race normal receive processing
2284 static int tiocsti(struct tty_struct *tty, char __user *p)
2287 struct tty_ldisc *ld;
2289 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2291 if (get_user(ch, p))
2293 tty_audit_tiocsti(tty, ch);
2294 ld = tty_ldisc_ref_wait(tty);
2295 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2296 tty_ldisc_deref(ld);
2301 * tiocgwinsz - implement window query ioctl
2303 * @arg: user buffer for result
2305 * Copies the kernel idea of the window size into the user buffer.
2307 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2311 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2315 mutex_lock(&tty->winsize_mutex);
2316 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2317 mutex_unlock(&tty->winsize_mutex);
2319 return err ? -EFAULT: 0;
2323 * tty_do_resize - resize event
2324 * @tty: tty being resized
2325 * @rows: rows (character)
2326 * @cols: cols (character)
2328 * Update the termios variables and send the necessary signals to
2329 * peform a terminal resize correctly
2332 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2337 mutex_lock(&tty->winsize_mutex);
2338 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2341 /* Signal the foreground process group */
2342 pgrp = tty_get_pgrp(tty);
2344 kill_pgrp(pgrp, SIGWINCH, 1);
2349 mutex_unlock(&tty->winsize_mutex);
2352 EXPORT_SYMBOL(tty_do_resize);
2355 * tiocswinsz - implement window size set ioctl
2356 * @tty; tty side of tty
2357 * @arg: user buffer for result
2359 * Copies the user idea of the window size to the kernel. Traditionally
2360 * this is just advisory information but for the Linux console it
2361 * actually has driver level meaning and triggers a VC resize.
2364 * Driver dependent. The default do_resize method takes the
2365 * tty termios mutex and ctrl_lock. The console takes its own lock
2366 * then calls into the default method.
2369 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2371 struct winsize tmp_ws;
2372 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2375 if (tty->ops->resize)
2376 return tty->ops->resize(tty, &tmp_ws);
2378 return tty_do_resize(tty, &tmp_ws);
2382 * tioccons - allow admin to move logical console
2383 * @file: the file to become console
2385 * Allow the administrator to move the redirected console device
2387 * Locking: uses redirect_lock to guard the redirect information
2390 static int tioccons(struct file *file)
2392 if (!capable(CAP_SYS_ADMIN))
2394 if (file->f_op->write == redirected_tty_write) {
2396 spin_lock(&redirect_lock);
2399 spin_unlock(&redirect_lock);
2404 spin_lock(&redirect_lock);
2406 spin_unlock(&redirect_lock);
2409 redirect = get_file(file);
2410 spin_unlock(&redirect_lock);
2415 * fionbio - non blocking ioctl
2416 * @file: file to set blocking value
2417 * @p: user parameter
2419 * Historical tty interfaces had a blocking control ioctl before
2420 * the generic functionality existed. This piece of history is preserved
2421 * in the expected tty API of posix OS's.
2423 * Locking: none, the open file handle ensures it won't go away.
2426 static int fionbio(struct file *file, int __user *p)
2430 if (get_user(nonblock, p))
2433 spin_lock(&file->f_lock);
2435 file->f_flags |= O_NONBLOCK;
2437 file->f_flags &= ~O_NONBLOCK;
2438 spin_unlock(&file->f_lock);
2443 * tiocsctty - set controlling tty
2444 * @tty: tty structure
2445 * @arg: user argument
2447 * This ioctl is used to manage job control. It permits a session
2448 * leader to set this tty as the controlling tty for the session.
2451 * Takes tty_mutex() to protect tty instance
2452 * Takes tasklist_lock internally to walk sessions
2453 * Takes ->siglock() when updating signal->tty
2456 static int tiocsctty(struct tty_struct *tty, int arg)
2460 mutex_lock(&tty_mutex);
2461 read_lock(&tasklist_lock);
2463 if (current->signal->leader && (task_session(current) == tty->session))
2467 * The process must be a session leader and
2468 * not have a controlling tty already.
2470 if (!current->signal->leader || current->signal->tty) {
2477 * This tty is already the controlling
2478 * tty for another session group!
2480 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2484 session_clear_tty(tty->session);
2492 read_unlock(&tasklist_lock);
2493 mutex_unlock(&tty_mutex);
2498 * tty_get_pgrp - return a ref counted pgrp pid
2501 * Returns a refcounted instance of the pid struct for the process
2502 * group controlling the tty.
2505 struct pid *tty_get_pgrp(struct tty_struct *tty)
2507 unsigned long flags;
2510 spin_lock_irqsave(&tty->ctrl_lock, flags);
2511 pgrp = get_pid(tty->pgrp);
2512 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2516 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2519 * tiocgpgrp - get process group
2520 * @tty: tty passed by user
2521 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2524 * Obtain the process group of the tty. If there is no process group
2527 * Locking: none. Reference to current->signal->tty is safe.
2530 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2535 * (tty == real_tty) is a cheap way of
2536 * testing if the tty is NOT a master pty.
2538 if (tty == real_tty && current->signal->tty != real_tty)
2540 pid = tty_get_pgrp(real_tty);
2541 ret = put_user(pid_vnr(pid), p);
2547 * tiocspgrp - attempt to set process group
2548 * @tty: tty passed by user
2549 * @real_tty: tty side device matching tty passed by user
2552 * Set the process group of the tty to the session passed. Only
2553 * permitted where the tty session is our session.
2555 * Locking: RCU, ctrl lock
2558 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2562 int retval = tty_check_change(real_tty);
2563 unsigned long flags;
2569 if (!current->signal->tty ||
2570 (current->signal->tty != real_tty) ||
2571 (real_tty->session != task_session(current)))
2573 if (get_user(pgrp_nr, p))
2578 pgrp = find_vpid(pgrp_nr);
2583 if (session_of_pgrp(pgrp) != task_session(current))
2586 spin_lock_irqsave(&tty->ctrl_lock, flags);
2587 put_pid(real_tty->pgrp);
2588 real_tty->pgrp = get_pid(pgrp);
2589 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2596 * tiocgsid - get session id
2597 * @tty: tty passed by user
2598 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2599 * @p: pointer to returned session id
2601 * Obtain the session id of the tty. If there is no session
2604 * Locking: none. Reference to current->signal->tty is safe.
2607 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2610 * (tty == real_tty) is a cheap way of
2611 * testing if the tty is NOT a master pty.
2613 if (tty == real_tty && current->signal->tty != real_tty)
2615 if (!real_tty->session)
2617 return put_user(pid_vnr(real_tty->session), p);
2621 * tiocsetd - set line discipline
2623 * @p: pointer to user data
2625 * Set the line discipline according to user request.
2627 * Locking: see tty_set_ldisc, this function is just a helper
2630 static int tiocsetd(struct tty_struct *tty, int __user *p)
2635 if (get_user(ldisc, p))
2638 ret = tty_set_ldisc(tty, ldisc);
2644 * send_break - performed time break
2645 * @tty: device to break on
2646 * @duration: timeout in mS
2648 * Perform a timed break on hardware that lacks its own driver level
2649 * timed break functionality.
2652 * atomic_write_lock serializes
2656 static int send_break(struct tty_struct *tty, unsigned int duration)
2660 if (tty->ops->break_ctl == NULL)
2663 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2664 retval = tty->ops->break_ctl(tty, duration);
2666 /* Do the work ourselves */
2667 if (tty_write_lock(tty, 0) < 0)
2669 retval = tty->ops->break_ctl(tty, -1);
2672 if (!signal_pending(current))
2673 msleep_interruptible(duration);
2674 retval = tty->ops->break_ctl(tty, 0);
2676 tty_write_unlock(tty);
2677 if (signal_pending(current))
2684 * tty_tiocmget - get modem status
2686 * @file: user file pointer
2687 * @p: pointer to result
2689 * Obtain the modem status bits from the tty driver if the feature
2690 * is supported. Return -EINVAL if it is not available.
2692 * Locking: none (up to the driver)
2695 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2697 int retval = -EINVAL;
2699 if (tty->ops->tiocmget) {
2700 retval = tty->ops->tiocmget(tty);
2703 retval = put_user(retval, p);
2709 * tty_tiocmset - set modem status
2711 * @cmd: command - clear bits, set bits or set all
2712 * @p: pointer to desired bits
2714 * Set the modem status bits from the tty driver if the feature
2715 * is supported. Return -EINVAL if it is not available.
2717 * Locking: none (up to the driver)
2720 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2724 unsigned int set, clear, val;
2726 if (tty->ops->tiocmset == NULL)
2729 retval = get_user(val, p);
2745 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2746 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2747 return tty->ops->tiocmset(tty, set, clear);
2750 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2752 int retval = -EINVAL;
2753 struct serial_icounter_struct icount;
2754 memset(&icount, 0, sizeof(icount));
2755 if (tty->ops->get_icount)
2756 retval = tty->ops->get_icount(tty, &icount);
2759 if (copy_to_user(arg, &icount, sizeof(icount)))
2765 * if pty, return the slave side (real_tty)
2766 * otherwise, return self
2768 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2770 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2771 tty->driver->subtype == PTY_TYPE_MASTER)
2777 * Split this up, as gcc can choke on it otherwise..
2779 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2781 struct tty_struct *tty = file_tty(file);
2782 struct tty_struct *real_tty;
2783 void __user *p = (void __user *)arg;
2785 struct tty_ldisc *ld;
2787 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2790 real_tty = tty_pair_get_tty(tty);
2793 * Factor out some common prep work
2801 retval = tty_check_change(tty);
2804 if (cmd != TIOCCBRK) {
2805 tty_wait_until_sent(tty, 0);
2806 if (signal_pending(current))
2817 return tiocsti(tty, p);
2819 return tiocgwinsz(real_tty, p);
2821 return tiocswinsz(real_tty, p);
2823 return real_tty != tty ? -EINVAL : tioccons(file);
2825 return fionbio(file, p);
2827 set_bit(TTY_EXCLUSIVE, &tty->flags);
2830 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2834 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2835 return put_user(excl, (int __user *)p);
2838 if (current->signal->tty != tty)
2843 return tiocsctty(tty, arg);
2845 return tiocgpgrp(tty, real_tty, p);
2847 return tiocspgrp(tty, real_tty, p);
2849 return tiocgsid(tty, real_tty, p);
2851 return put_user(tty->ldisc->ops->num, (int __user *)p);
2853 return tiocsetd(tty, p);
2855 if (!capable(CAP_SYS_ADMIN))
2861 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2862 return put_user(ret, (unsigned int __user *)p);
2867 case TIOCSBRK: /* Turn break on, unconditionally */
2868 if (tty->ops->break_ctl)
2869 return tty->ops->break_ctl(tty, -1);
2871 case TIOCCBRK: /* Turn break off, unconditionally */
2872 if (tty->ops->break_ctl)
2873 return tty->ops->break_ctl(tty, 0);
2875 case TCSBRK: /* SVID version: non-zero arg --> no break */
2876 /* non-zero arg means wait for all output data
2877 * to be sent (performed above) but don't send break.
2878 * This is used by the tcdrain() termios function.
2881 return send_break(tty, 250);
2883 case TCSBRKP: /* support for POSIX tcsendbreak() */
2884 return send_break(tty, arg ? arg*100 : 250);
2887 return tty_tiocmget(tty, p);
2891 return tty_tiocmset(tty, cmd, p);
2893 retval = tty_tiocgicount(tty, p);
2894 /* For the moment allow fall through to the old method */
2895 if (retval != -EINVAL)
2902 /* flush tty buffer and allow ldisc to process ioctl */
2903 tty_buffer_flush(tty);
2908 if (tty->ops->ioctl) {
2909 retval = (tty->ops->ioctl)(tty, cmd, arg);
2910 if (retval != -ENOIOCTLCMD)
2913 ld = tty_ldisc_ref_wait(tty);
2915 if (ld->ops->ioctl) {
2916 retval = ld->ops->ioctl(tty, file, cmd, arg);
2917 if (retval == -ENOIOCTLCMD)
2920 tty_ldisc_deref(ld);
2924 #ifdef CONFIG_COMPAT
2925 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2928 struct tty_struct *tty = file_tty(file);
2929 struct tty_ldisc *ld;
2930 int retval = -ENOIOCTLCMD;
2932 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2935 if (tty->ops->compat_ioctl) {
2936 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2937 if (retval != -ENOIOCTLCMD)
2941 ld = tty_ldisc_ref_wait(tty);
2942 if (ld->ops->compat_ioctl)
2943 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2945 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2946 tty_ldisc_deref(ld);
2952 static int this_tty(const void *t, struct file *file, unsigned fd)
2954 if (likely(file->f_op->read != tty_read))
2956 return file_tty(file) != t ? 0 : fd + 1;
2960 * This implements the "Secure Attention Key" --- the idea is to
2961 * prevent trojan horses by killing all processes associated with this
2962 * tty when the user hits the "Secure Attention Key". Required for
2963 * super-paranoid applications --- see the Orange Book for more details.
2965 * This code could be nicer; ideally it should send a HUP, wait a few
2966 * seconds, then send a INT, and then a KILL signal. But you then
2967 * have to coordinate with the init process, since all processes associated
2968 * with the current tty must be dead before the new getty is allowed
2971 * Now, if it would be correct ;-/ The current code has a nasty hole -
2972 * it doesn't catch files in flight. We may send the descriptor to ourselves
2973 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2975 * Nasty bug: do_SAK is being called in interrupt context. This can
2976 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2978 void __do_SAK(struct tty_struct *tty)
2983 struct task_struct *g, *p;
2984 struct pid *session;
2989 session = tty->session;
2991 tty_ldisc_flush(tty);
2993 tty_driver_flush_buffer(tty);
2995 read_lock(&tasklist_lock);
2996 /* Kill the entire session */
2997 do_each_pid_task(session, PIDTYPE_SID, p) {
2998 printk(KERN_NOTICE "SAK: killed process %d"
2999 " (%s): task_session(p)==tty->session\n",
3000 task_pid_nr(p), p->comm);
3001 send_sig(SIGKILL, p, 1);
3002 } while_each_pid_task(session, PIDTYPE_SID, p);
3003 /* Now kill any processes that happen to have the
3006 do_each_thread(g, p) {
3007 if (p->signal->tty == tty) {
3008 printk(KERN_NOTICE "SAK: killed process %d"
3009 " (%s): task_session(p)==tty->session\n",
3010 task_pid_nr(p), p->comm);
3011 send_sig(SIGKILL, p, 1);
3015 i = iterate_fd(p->files, 0, this_tty, tty);
3017 printk(KERN_NOTICE "SAK: killed process %d"
3018 " (%s): fd#%d opened to the tty\n",
3019 task_pid_nr(p), p->comm, i - 1);
3020 force_sig(SIGKILL, p);
3023 } while_each_thread(g, p);
3024 read_unlock(&tasklist_lock);
3028 static void do_SAK_work(struct work_struct *work)
3030 struct tty_struct *tty =
3031 container_of(work, struct tty_struct, SAK_work);
3036 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3037 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3038 * the values which we write to it will be identical to the values which it
3039 * already has. --akpm
3041 void do_SAK(struct tty_struct *tty)
3045 schedule_work(&tty->SAK_work);
3048 EXPORT_SYMBOL(do_SAK);
3050 static int dev_match_devt(struct device *dev, const void *data)
3052 const dev_t *devt = data;
3053 return dev->devt == *devt;
3056 /* Must put_device() after it's unused! */
3057 static struct device *tty_get_device(struct tty_struct *tty)
3059 dev_t devt = tty_devnum(tty);
3060 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3067 * This subroutine allocates and initializes a tty structure.
3069 * Locking: none - tty in question is not exposed at this point
3072 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3074 struct tty_struct *tty;
3076 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3080 kref_init(&tty->kref);
3081 tty->magic = TTY_MAGIC;
3082 tty_ldisc_init(tty);
3083 tty->session = NULL;
3085 mutex_init(&tty->legacy_mutex);
3086 mutex_init(&tty->throttle_mutex);
3087 init_rwsem(&tty->termios_rwsem);
3088 mutex_init(&tty->winsize_mutex);
3089 init_ldsem(&tty->ldisc_sem);
3090 init_waitqueue_head(&tty->write_wait);
3091 init_waitqueue_head(&tty->read_wait);
3092 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3093 mutex_init(&tty->atomic_write_lock);
3094 spin_lock_init(&tty->ctrl_lock);
3095 spin_lock_init(&tty->flow_lock);
3096 INIT_LIST_HEAD(&tty->tty_files);
3097 INIT_WORK(&tty->SAK_work, do_SAK_work);
3099 tty->driver = driver;
3100 tty->ops = driver->ops;
3102 tty_line_name(driver, idx, tty->name);
3103 tty->dev = tty_get_device(tty);
3109 * deinitialize_tty_struct
3110 * @tty: tty to deinitialize
3112 * This subroutine deinitializes a tty structure that has been newly
3113 * allocated but tty_release cannot be called on that yet.
3115 * Locking: none - tty in question must not be exposed at this point
3117 void deinitialize_tty_struct(struct tty_struct *tty)
3119 tty_ldisc_deinit(tty);
3123 * tty_put_char - write one character to a tty
3127 * Write one byte to the tty using the provided put_char method
3128 * if present. Returns the number of characters successfully output.
3130 * Note: the specific put_char operation in the driver layer may go
3131 * away soon. Don't call it directly, use this method
3134 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3136 if (tty->ops->put_char)
3137 return tty->ops->put_char(tty, ch);
3138 return tty->ops->write(tty, &ch, 1);
3140 EXPORT_SYMBOL_GPL(tty_put_char);
3142 struct class *tty_class;
3144 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3145 unsigned int index, unsigned int count)
3147 /* init here, since reused cdevs cause crashes */
3148 cdev_init(&driver->cdevs[index], &tty_fops);
3149 driver->cdevs[index].owner = driver->owner;
3150 return cdev_add(&driver->cdevs[index], dev, count);
3154 * tty_register_device - register a tty device
3155 * @driver: the tty driver that describes the tty device
3156 * @index: the index in the tty driver for this tty device
3157 * @device: a struct device that is associated with this tty device.
3158 * This field is optional, if there is no known struct device
3159 * for this tty device it can be set to NULL safely.
3161 * Returns a pointer to the struct device for this tty device
3162 * (or ERR_PTR(-EFOO) on error).
3164 * This call is required to be made to register an individual tty device
3165 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3166 * that bit is not set, this function should not be called by a tty
3172 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3173 struct device *device)
3175 return tty_register_device_attr(driver, index, device, NULL, NULL);
3177 EXPORT_SYMBOL(tty_register_device);
3179 static void tty_device_create_release(struct device *dev)
3181 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3186 * tty_register_device_attr - register a tty device
3187 * @driver: the tty driver that describes the tty device
3188 * @index: the index in the tty driver for this tty device
3189 * @device: a struct device that is associated with this tty device.
3190 * This field is optional, if there is no known struct device
3191 * for this tty device it can be set to NULL safely.
3192 * @drvdata: Driver data to be set to device.
3193 * @attr_grp: Attribute group to be set on device.
3195 * Returns a pointer to the struct device for this tty device
3196 * (or ERR_PTR(-EFOO) on error).
3198 * This call is required to be made to register an individual tty device
3199 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3200 * that bit is not set, this function should not be called by a tty
3205 struct device *tty_register_device_attr(struct tty_driver *driver,
3206 unsigned index, struct device *device,
3208 const struct attribute_group **attr_grp)
3211 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3212 struct device *dev = NULL;
3213 int retval = -ENODEV;
3216 if (index >= driver->num) {
3217 printk(KERN_ERR "Attempt to register invalid tty line number "
3219 return ERR_PTR(-EINVAL);
3222 if (driver->type == TTY_DRIVER_TYPE_PTY)
3223 pty_line_name(driver, index, name);
3225 tty_line_name(driver, index, name);
3227 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3228 retval = tty_cdev_add(driver, devt, index, 1);
3234 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3241 dev->class = tty_class;
3242 dev->parent = device;
3243 dev->release = tty_device_create_release;
3244 dev_set_name(dev, "%s", name);
3245 dev->groups = attr_grp;
3246 dev_set_drvdata(dev, drvdata);
3248 retval = device_register(dev);
3257 cdev_del(&driver->cdevs[index]);
3258 return ERR_PTR(retval);
3260 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3263 * tty_unregister_device - unregister a tty device
3264 * @driver: the tty driver that describes the tty device
3265 * @index: the index in the tty driver for this tty device
3267 * If a tty device is registered with a call to tty_register_device() then
3268 * this function must be called when the tty device is gone.
3273 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3275 device_destroy(tty_class,
3276 MKDEV(driver->major, driver->minor_start) + index);
3277 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3278 cdev_del(&driver->cdevs[index]);
3280 EXPORT_SYMBOL(tty_unregister_device);
3283 * __tty_alloc_driver -- allocate tty driver
3284 * @lines: count of lines this driver can handle at most
3285 * @owner: module which is repsonsible for this driver
3286 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3288 * This should not be called directly, some of the provided macros should be
3289 * used instead. Use IS_ERR and friends on @retval.
3291 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3292 unsigned long flags)
3294 struct tty_driver *driver;
3295 unsigned int cdevs = 1;
3298 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3299 return ERR_PTR(-EINVAL);
3301 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3303 return ERR_PTR(-ENOMEM);
3305 kref_init(&driver->kref);
3306 driver->magic = TTY_DRIVER_MAGIC;
3307 driver->num = lines;
3308 driver->owner = owner;
3309 driver->flags = flags;
3311 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3312 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3314 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3316 if (!driver->ttys || !driver->termios) {
3322 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3323 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3325 if (!driver->ports) {
3332 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3333 if (!driver->cdevs) {
3340 kfree(driver->ports);
3341 kfree(driver->ttys);
3342 kfree(driver->termios);
3344 return ERR_PTR(err);
3346 EXPORT_SYMBOL(__tty_alloc_driver);
3348 static void destruct_tty_driver(struct kref *kref)
3350 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3352 struct ktermios *tp;
3354 if (driver->flags & TTY_DRIVER_INSTALLED) {
3356 * Free the termios and termios_locked structures because
3357 * we don't want to get memory leaks when modular tty
3358 * drivers are removed from the kernel.
3360 for (i = 0; i < driver->num; i++) {
3361 tp = driver->termios[i];
3363 driver->termios[i] = NULL;
3366 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3367 tty_unregister_device(driver, i);
3369 proc_tty_unregister_driver(driver);
3370 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3371 cdev_del(&driver->cdevs[0]);
3373 kfree(driver->cdevs);
3374 kfree(driver->ports);
3375 kfree(driver->termios);
3376 kfree(driver->ttys);
3380 void tty_driver_kref_put(struct tty_driver *driver)
3382 kref_put(&driver->kref, destruct_tty_driver);
3384 EXPORT_SYMBOL(tty_driver_kref_put);
3386 void tty_set_operations(struct tty_driver *driver,
3387 const struct tty_operations *op)
3391 EXPORT_SYMBOL(tty_set_operations);
3393 void put_tty_driver(struct tty_driver *d)
3395 tty_driver_kref_put(d);
3397 EXPORT_SYMBOL(put_tty_driver);
3400 * Called by a tty driver to register itself.
3402 int tty_register_driver(struct tty_driver *driver)
3409 if (!driver->major) {
3410 error = alloc_chrdev_region(&dev, driver->minor_start,
3411 driver->num, driver->name);
3413 driver->major = MAJOR(dev);
3414 driver->minor_start = MINOR(dev);
3417 dev = MKDEV(driver->major, driver->minor_start);
3418 error = register_chrdev_region(dev, driver->num, driver->name);
3423 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3424 error = tty_cdev_add(driver, dev, 0, driver->num);
3426 goto err_unreg_char;
3429 mutex_lock(&tty_mutex);
3430 list_add(&driver->tty_drivers, &tty_drivers);
3431 mutex_unlock(&tty_mutex);
3433 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3434 for (i = 0; i < driver->num; i++) {
3435 d = tty_register_device(driver, i, NULL);
3438 goto err_unreg_devs;
3442 proc_tty_register_driver(driver);
3443 driver->flags |= TTY_DRIVER_INSTALLED;
3447 for (i--; i >= 0; i--)
3448 tty_unregister_device(driver, i);
3450 mutex_lock(&tty_mutex);
3451 list_del(&driver->tty_drivers);
3452 mutex_unlock(&tty_mutex);
3455 unregister_chrdev_region(dev, driver->num);
3459 EXPORT_SYMBOL(tty_register_driver);
3462 * Called by a tty driver to unregister itself.
3464 int tty_unregister_driver(struct tty_driver *driver)
3468 if (driver->refcount)
3471 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3473 mutex_lock(&tty_mutex);
3474 list_del(&driver->tty_drivers);
3475 mutex_unlock(&tty_mutex);
3479 EXPORT_SYMBOL(tty_unregister_driver);
3481 dev_t tty_devnum(struct tty_struct *tty)
3483 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3485 EXPORT_SYMBOL(tty_devnum);
3487 void tty_default_fops(struct file_operations *fops)
3493 * Initialize the console device. This is called *early*, so
3494 * we can't necessarily depend on lots of kernel help here.
3495 * Just do some early initializations, and do the complex setup
3498 void __init console_init(void)
3502 /* Setup the default TTY line discipline. */
3506 * set up the console device so that later boot sequences can
3507 * inform about problems etc..
3509 call = __con_initcall_start;
3510 while (call < __con_initcall_end) {
3516 static char *tty_devnode(struct device *dev, umode_t *mode)
3520 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3521 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3526 static int __init tty_class_init(void)
3528 tty_class = class_create(THIS_MODULE, "tty");
3529 if (IS_ERR(tty_class))
3530 return PTR_ERR(tty_class);
3531 tty_class->devnode = tty_devnode;
3535 postcore_initcall(tty_class_init);
3537 /* 3/2004 jmc: why do these devices exist? */
3538 static struct cdev tty_cdev, console_cdev;
3540 static ssize_t show_cons_active(struct device *dev,
3541 struct device_attribute *attr, char *buf)
3543 struct console *cs[16];
3549 for_each_console(c) {
3554 if ((c->flags & CON_ENABLED) == 0)
3557 if (i >= ARRAY_SIZE(cs))
3561 int index = cs[i]->index;
3562 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3564 /* don't resolve tty0 as some programs depend on it */
3565 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3566 count += tty_line_name(drv, index, buf + count);
3568 count += sprintf(buf + count, "%s%d",
3569 cs[i]->name, cs[i]->index);
3571 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3577 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3579 static struct device *consdev;
3581 void console_sysfs_notify(void)
3584 sysfs_notify(&consdev->kobj, NULL, "active");
3588 * Ok, now we can initialize the rest of the tty devices and can count
3589 * on memory allocations, interrupts etc..
3591 int __init tty_init(void)
3593 cdev_init(&tty_cdev, &tty_fops);
3594 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3595 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3596 panic("Couldn't register /dev/tty driver\n");
3597 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3599 cdev_init(&console_cdev, &console_fops);
3600 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3601 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3602 panic("Couldn't register /dev/console driver\n");
3603 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3605 if (IS_ERR(consdev))
3608 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3611 vty_init(&console_fops);