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);
505 /* Called under the sighand lock */
507 static void __proc_set_tty(struct tty_struct *tty)
511 /* We should not have a session or pgrp to put here but.... */
512 spin_lock_irqsave(&tty->ctrl_lock, flags);
513 put_pid(tty->session);
515 tty->pgrp = get_pid(task_pgrp(current));
516 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
517 tty->session = get_pid(task_session(current));
518 if (current->signal->tty) {
519 printk(KERN_DEBUG "tty not NULL!!\n");
520 tty_kref_put(current->signal->tty);
523 put_pid(current->signal->tty_old_pgrp);
524 current->signal->tty = tty_kref_get(tty);
525 current->signal->tty_old_pgrp = NULL;
528 static void proc_set_tty(struct tty_struct *tty)
530 spin_lock_irq(¤t->sighand->siglock);
532 spin_unlock_irq(¤t->sighand->siglock);
535 struct tty_struct *get_current_tty(void)
537 struct tty_struct *tty;
540 spin_lock_irqsave(¤t->sighand->siglock, flags);
541 tty = tty_kref_get(current->signal->tty);
542 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
545 EXPORT_SYMBOL_GPL(get_current_tty);
547 static void session_clear_tty(struct pid *session)
549 struct task_struct *p;
550 do_each_pid_task(session, PIDTYPE_SID, p) {
552 } while_each_pid_task(session, PIDTYPE_SID, p);
556 * tty_wakeup - request more data
559 * Internal and external helper for wakeups of tty. This function
560 * informs the line discipline if present that the driver is ready
561 * to receive more output data.
564 void tty_wakeup(struct tty_struct *tty)
566 struct tty_ldisc *ld;
568 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
569 ld = tty_ldisc_ref(tty);
571 if (ld->ops->write_wakeup)
572 ld->ops->write_wakeup(tty);
576 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
579 EXPORT_SYMBOL_GPL(tty_wakeup);
582 * tty_signal_session_leader - sends SIGHUP to session leader
583 * @tty controlling tty
584 * @exit_session if non-zero, signal all foreground group processes
586 * Send SIGHUP and SIGCONT to the session leader and its process group.
587 * Optionally, signal all processes in the foreground process group.
589 * Returns the number of processes in the session with this tty
590 * as their controlling terminal. This value is used to drop
591 * tty references for those processes.
593 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
595 struct task_struct *p;
597 struct pid *tty_pgrp = NULL;
599 read_lock(&tasklist_lock);
601 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
602 spin_lock_irq(&p->sighand->siglock);
603 if (p->signal->tty == tty) {
604 p->signal->tty = NULL;
605 /* We defer the dereferences outside fo
609 if (!p->signal->leader) {
610 spin_unlock_irq(&p->sighand->siglock);
613 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
614 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
615 put_pid(p->signal->tty_old_pgrp); /* A noop */
616 spin_lock(&tty->ctrl_lock);
617 tty_pgrp = get_pid(tty->pgrp);
619 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
620 spin_unlock(&tty->ctrl_lock);
621 spin_unlock_irq(&p->sighand->siglock);
622 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
624 read_unlock(&tasklist_lock);
628 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
636 * __tty_hangup - actual handler for hangup events
639 * This can be called by a "kworker" kernel thread. That is process
640 * synchronous but doesn't hold any locks, so we need to make sure we
641 * have the appropriate locks for what we're doing.
643 * The hangup event clears any pending redirections onto the hung up
644 * device. It ensures future writes will error and it does the needed
645 * line discipline hangup and signal delivery. The tty object itself
650 * redirect lock for undoing redirection
651 * file list lock for manipulating list of ttys
652 * tty_ldiscs_lock from called functions
653 * termios_rwsem resetting termios data
654 * tasklist_lock to walk task list for hangup event
655 * ->siglock to protect ->signal/->sighand
657 static void __tty_hangup(struct tty_struct *tty, int exit_session)
659 struct file *cons_filp = NULL;
660 struct file *filp, *f = NULL;
661 struct tty_file_private *priv;
662 int closecount = 0, n;
669 spin_lock(&redirect_lock);
670 if (redirect && file_tty(redirect) == tty) {
674 spin_unlock(&redirect_lock);
678 if (test_bit(TTY_HUPPED, &tty->flags)) {
683 /* some functions below drop BTM, so we need this bit */
684 set_bit(TTY_HUPPING, &tty->flags);
686 /* inuse_filps is protected by the single tty lock,
687 this really needs to change if we want to flush the
688 workqueue with the lock held */
689 check_tty_count(tty, "tty_hangup");
691 spin_lock(&tty_files_lock);
692 /* This breaks for file handles being sent over AF_UNIX sockets ? */
693 list_for_each_entry(priv, &tty->tty_files, list) {
695 if (filp->f_op->write == redirected_tty_write)
697 if (filp->f_op->write != tty_write)
700 __tty_fasync(-1, filp, 0); /* can't block */
701 filp->f_op = &hung_up_tty_fops;
703 spin_unlock(&tty_files_lock);
705 refs = tty_signal_session_leader(tty, exit_session);
706 /* Account for the p->signal references we killed */
711 * it drops BTM and thus races with reopen
712 * we protect the race by TTY_HUPPING
714 tty_ldisc_hangup(tty);
716 spin_lock_irq(&tty->ctrl_lock);
717 clear_bit(TTY_THROTTLED, &tty->flags);
718 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
719 put_pid(tty->session);
723 tty->ctrl_status = 0;
724 spin_unlock_irq(&tty->ctrl_lock);
727 * If one of the devices matches a console pointer, we
728 * cannot just call hangup() because that will cause
729 * tty->count and state->count to go out of sync.
730 * So we just call close() the right number of times.
734 for (n = 0; n < closecount; n++)
735 tty->ops->close(tty, cons_filp);
736 } else if (tty->ops->hangup)
737 tty->ops->hangup(tty);
739 * We don't want to have driver/ldisc interactions beyond
740 * the ones we did here. The driver layer expects no
741 * calls after ->hangup() from the ldisc side. However we
742 * can't yet guarantee all that.
744 set_bit(TTY_HUPPED, &tty->flags);
745 clear_bit(TTY_HUPPING, &tty->flags);
753 static void do_tty_hangup(struct work_struct *work)
755 struct tty_struct *tty =
756 container_of(work, struct tty_struct, hangup_work);
758 __tty_hangup(tty, 0);
762 * tty_hangup - trigger a hangup event
763 * @tty: tty to hangup
765 * A carrier loss (virtual or otherwise) has occurred on this like
766 * schedule a hangup sequence to run after this event.
769 void tty_hangup(struct tty_struct *tty)
771 #ifdef TTY_DEBUG_HANGUP
773 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
775 schedule_work(&tty->hangup_work);
778 EXPORT_SYMBOL(tty_hangup);
781 * tty_vhangup - process vhangup
782 * @tty: tty to hangup
784 * The user has asked via system call for the terminal to be hung up.
785 * We do this synchronously so that when the syscall returns the process
786 * is complete. That guarantee is necessary for security reasons.
789 void tty_vhangup(struct tty_struct *tty)
791 #ifdef TTY_DEBUG_HANGUP
794 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
796 __tty_hangup(tty, 0);
799 EXPORT_SYMBOL(tty_vhangup);
803 * tty_vhangup_self - process vhangup for own ctty
805 * Perform a vhangup on the current controlling tty
808 void tty_vhangup_self(void)
810 struct tty_struct *tty;
812 tty = get_current_tty();
820 * tty_vhangup_session - hangup session leader exit
821 * @tty: tty to hangup
823 * The session leader is exiting and hanging up its controlling terminal.
824 * Every process in the foreground process group is signalled SIGHUP.
826 * We do this synchronously so that when the syscall returns the process
827 * is complete. That guarantee is necessary for security reasons.
830 static void tty_vhangup_session(struct tty_struct *tty)
832 #ifdef TTY_DEBUG_HANGUP
835 printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty, buf));
837 __tty_hangup(tty, 1);
841 * tty_hung_up_p - was tty hung up
842 * @filp: file pointer of tty
844 * Return true if the tty has been subject to a vhangup or a carrier
848 int tty_hung_up_p(struct file *filp)
850 return (filp->f_op == &hung_up_tty_fops);
853 EXPORT_SYMBOL(tty_hung_up_p);
856 * disassociate_ctty - disconnect controlling tty
857 * @on_exit: true if exiting so need to "hang up" the session
859 * This function is typically called only by the session leader, when
860 * it wants to disassociate itself from its controlling tty.
862 * It performs the following functions:
863 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
864 * (2) Clears the tty from being controlling the session
865 * (3) Clears the controlling tty for all processes in the
868 * The argument on_exit is set to 1 if called when a process is
869 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
872 * BTM is taken for hysterical raisins, and held when
873 * called from no_tty().
874 * tty_mutex is taken to protect tty
875 * ->siglock is taken to protect ->signal/->sighand
876 * tasklist_lock is taken to walk process list for sessions
877 * ->siglock is taken to protect ->signal/->sighand
880 void disassociate_ctty(int on_exit)
882 struct tty_struct *tty;
884 if (!current->signal->leader)
887 tty = get_current_tty();
889 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
890 tty_vhangup_session(tty);
892 struct pid *tty_pgrp = tty_get_pgrp(tty);
894 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
896 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
902 } else if (on_exit) {
903 struct pid *old_pgrp;
904 spin_lock_irq(¤t->sighand->siglock);
905 old_pgrp = current->signal->tty_old_pgrp;
906 current->signal->tty_old_pgrp = NULL;
907 spin_unlock_irq(¤t->sighand->siglock);
909 kill_pgrp(old_pgrp, SIGHUP, on_exit);
910 kill_pgrp(old_pgrp, SIGCONT, on_exit);
916 spin_lock_irq(¤t->sighand->siglock);
917 put_pid(current->signal->tty_old_pgrp);
918 current->signal->tty_old_pgrp = NULL;
920 tty = tty_kref_get(current->signal->tty);
923 spin_lock_irqsave(&tty->ctrl_lock, flags);
924 put_pid(tty->session);
928 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
931 #ifdef TTY_DEBUG_HANGUP
932 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
937 spin_unlock_irq(¤t->sighand->siglock);
938 /* Now clear signal->tty under the lock */
939 read_lock(&tasklist_lock);
940 session_clear_tty(task_session(current));
941 read_unlock(&tasklist_lock);
946 * no_tty - Ensure the current process does not have a controlling tty
950 /* FIXME: Review locking here. The tty_lock never covered any race
951 between a new association and proc_clear_tty but possible we need
952 to protect against this anyway */
953 struct task_struct *tsk = current;
954 disassociate_ctty(0);
960 * stop_tty - propagate flow control
963 * Perform flow control to the driver. May be called
964 * on an already stopped device and will not re-call the driver
967 * This functionality is used by both the line disciplines for
968 * halting incoming flow and by the driver. It may therefore be
969 * called from any context, may be under the tty atomic_write_lock
976 void __stop_tty(struct tty_struct *tty)
982 (tty->ops->stop)(tty);
985 void stop_tty(struct tty_struct *tty)
989 spin_lock_irqsave(&tty->flow_lock, flags);
991 spin_unlock_irqrestore(&tty->flow_lock, flags);
993 EXPORT_SYMBOL(stop_tty);
996 * start_tty - propagate flow control
999 * Start a tty that has been stopped if at all possible. If this
1000 * tty was previous stopped and is now being started, the driver
1001 * start method is invoked and the line discipline woken.
1007 void __start_tty(struct tty_struct *tty)
1009 if (!tty->stopped || tty->flow_stopped)
1012 if (tty->ops->start)
1013 (tty->ops->start)(tty);
1017 void start_tty(struct tty_struct *tty)
1019 unsigned long flags;
1021 spin_lock_irqsave(&tty->flow_lock, flags);
1023 spin_unlock_irqrestore(&tty->flow_lock, flags);
1025 EXPORT_SYMBOL(start_tty);
1027 /* We limit tty time update visibility to every 8 seconds or so. */
1028 static void tty_update_time(struct timespec *time)
1030 unsigned long sec = get_seconds() & ~7;
1031 if ((long)(sec - time->tv_sec) > 0)
1036 * tty_read - read method for tty device files
1037 * @file: pointer to tty file
1039 * @count: size of user buffer
1042 * Perform the read system call function on this terminal device. Checks
1043 * for hung up devices before calling the line discipline method.
1046 * Locks the line discipline internally while needed. Multiple
1047 * read calls may be outstanding in parallel.
1050 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1054 struct inode *inode = file_inode(file);
1055 struct tty_struct *tty = file_tty(file);
1056 struct tty_ldisc *ld;
1058 if (tty_paranoia_check(tty, inode, "tty_read"))
1060 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1063 /* We want to wait for the line discipline to sort out in this
1065 ld = tty_ldisc_ref_wait(tty);
1067 i = (ld->ops->read)(tty, file, buf, count);
1070 tty_ldisc_deref(ld);
1073 tty_update_time(&inode->i_atime);
1078 static void tty_write_unlock(struct tty_struct *tty)
1080 mutex_unlock(&tty->atomic_write_lock);
1081 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1084 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1086 if (!mutex_trylock(&tty->atomic_write_lock)) {
1089 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1090 return -ERESTARTSYS;
1096 * Split writes up in sane blocksizes to avoid
1097 * denial-of-service type attacks
1099 static inline ssize_t do_tty_write(
1100 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1101 struct tty_struct *tty,
1103 const char __user *buf,
1106 ssize_t ret, written = 0;
1109 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1114 * We chunk up writes into a temporary buffer. This
1115 * simplifies low-level drivers immensely, since they
1116 * don't have locking issues and user mode accesses.
1118 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1121 * The default chunk-size is 2kB, because the NTTY
1122 * layer has problems with bigger chunks. It will
1123 * claim to be able to handle more characters than
1126 * FIXME: This can probably go away now except that 64K chunks
1127 * are too likely to fail unless switched to vmalloc...
1130 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1135 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1136 if (tty->write_cnt < chunk) {
1137 unsigned char *buf_chunk;
1142 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1147 kfree(tty->write_buf);
1148 tty->write_cnt = chunk;
1149 tty->write_buf = buf_chunk;
1152 /* Do the write .. */
1154 size_t size = count;
1158 if (copy_from_user(tty->write_buf, buf, size))
1160 ret = write(tty, file, tty->write_buf, size);
1169 if (signal_pending(current))
1174 tty_update_time(&file_inode(file)->i_mtime);
1178 tty_write_unlock(tty);
1183 * tty_write_message - write a message to a certain tty, not just the console.
1184 * @tty: the destination tty_struct
1185 * @msg: the message to write
1187 * This is used for messages that need to be redirected to a specific tty.
1188 * We don't put it into the syslog queue right now maybe in the future if
1191 * We must still hold the BTM and test the CLOSING flag for the moment.
1194 void tty_write_message(struct tty_struct *tty, char *msg)
1197 mutex_lock(&tty->atomic_write_lock);
1199 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1201 tty->ops->write(tty, msg, strlen(msg));
1204 tty_write_unlock(tty);
1211 * tty_write - write method for tty device file
1212 * @file: tty file pointer
1213 * @buf: user data to write
1214 * @count: bytes to write
1217 * Write data to a tty device via the line discipline.
1220 * Locks the line discipline as required
1221 * Writes to the tty driver are serialized by the atomic_write_lock
1222 * and are then processed in chunks to the device. The line discipline
1223 * write method will not be invoked in parallel for each device.
1226 static ssize_t tty_write(struct file *file, const char __user *buf,
1227 size_t count, loff_t *ppos)
1229 struct tty_struct *tty = file_tty(file);
1230 struct tty_ldisc *ld;
1233 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1235 if (!tty || !tty->ops->write ||
1236 (test_bit(TTY_IO_ERROR, &tty->flags)))
1238 /* Short term debug to catch buggy drivers */
1239 if (tty->ops->write_room == NULL)
1240 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1242 ld = tty_ldisc_ref_wait(tty);
1243 if (!ld->ops->write)
1246 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1247 tty_ldisc_deref(ld);
1251 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1252 size_t count, loff_t *ppos)
1254 struct file *p = NULL;
1256 spin_lock(&redirect_lock);
1258 p = get_file(redirect);
1259 spin_unlock(&redirect_lock);
1263 res = vfs_write(p, buf, count, &p->f_pos);
1267 return tty_write(file, buf, count, ppos);
1271 * tty_send_xchar - send priority character
1273 * Send a high priority character to the tty even if stopped
1275 * Locking: none for xchar method, write ordering for write method.
1278 int tty_send_xchar(struct tty_struct *tty, char ch)
1280 int was_stopped = tty->stopped;
1282 if (tty->ops->send_xchar) {
1283 tty->ops->send_xchar(tty, ch);
1287 if (tty_write_lock(tty, 0) < 0)
1288 return -ERESTARTSYS;
1292 tty->ops->write(tty, &ch, 1);
1295 tty_write_unlock(tty);
1299 static char ptychar[] = "pqrstuvwxyzabcde";
1302 * pty_line_name - generate name for a pty
1303 * @driver: the tty driver in use
1304 * @index: the minor number
1305 * @p: output buffer of at least 6 bytes
1307 * Generate a name from a driver reference and write it to the output
1312 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1314 int i = index + driver->name_base;
1315 /* ->name is initialized to "ttyp", but "tty" is expected */
1316 sprintf(p, "%s%c%x",
1317 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1318 ptychar[i >> 4 & 0xf], i & 0xf);
1322 * tty_line_name - generate name for a tty
1323 * @driver: the tty driver in use
1324 * @index: the minor number
1325 * @p: output buffer of at least 7 bytes
1327 * Generate a name from a driver reference and write it to the output
1332 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1334 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1335 return sprintf(p, "%s", driver->name);
1337 return sprintf(p, "%s%d", driver->name,
1338 index + driver->name_base);
1342 * tty_driver_lookup_tty() - find an existing tty, if any
1343 * @driver: the driver for the tty
1344 * @idx: the minor number
1346 * Return the tty, if found or ERR_PTR() otherwise.
1348 * Locking: tty_mutex must be held. If tty is found, the mutex must
1349 * be held until the 'fast-open' is also done. Will change once we
1350 * have refcounting in the driver and per driver locking
1352 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1353 struct inode *inode, int idx)
1355 if (driver->ops->lookup)
1356 return driver->ops->lookup(driver, inode, idx);
1358 return driver->ttys[idx];
1362 * tty_init_termios - helper for termios setup
1363 * @tty: the tty to set up
1365 * Initialise the termios structures for this tty. Thus runs under
1366 * the tty_mutex currently so we can be relaxed about ordering.
1369 int tty_init_termios(struct tty_struct *tty)
1371 struct ktermios *tp;
1372 int idx = tty->index;
1374 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1375 tty->termios = tty->driver->init_termios;
1377 /* Check for lazy saved data */
1378 tp = tty->driver->termios[idx];
1382 tty->termios = tty->driver->init_termios;
1384 /* Compatibility until drivers always set this */
1385 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1386 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1389 EXPORT_SYMBOL_GPL(tty_init_termios);
1391 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1393 int ret = tty_init_termios(tty);
1397 tty_driver_kref_get(driver);
1399 driver->ttys[tty->index] = tty;
1402 EXPORT_SYMBOL_GPL(tty_standard_install);
1405 * tty_driver_install_tty() - install a tty entry in the driver
1406 * @driver: the driver for the tty
1409 * Install a tty object into the driver tables. The tty->index field
1410 * will be set by the time this is called. This method is responsible
1411 * for ensuring any need additional structures are allocated and
1414 * Locking: tty_mutex for now
1416 static int tty_driver_install_tty(struct tty_driver *driver,
1417 struct tty_struct *tty)
1419 return driver->ops->install ? driver->ops->install(driver, tty) :
1420 tty_standard_install(driver, tty);
1424 * tty_driver_remove_tty() - remove a tty from the driver tables
1425 * @driver: the driver for the tty
1426 * @idx: the minor number
1428 * Remvoe a tty object from the driver tables. The tty->index field
1429 * will be set by the time this is called.
1431 * Locking: tty_mutex for now
1433 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1435 if (driver->ops->remove)
1436 driver->ops->remove(driver, tty);
1438 driver->ttys[tty->index] = NULL;
1442 * tty_reopen() - fast re-open of an open tty
1443 * @tty - the tty to open
1445 * Return 0 on success, -errno on error.
1447 * Locking: tty_mutex must be held from the time the tty was found
1448 * till this open completes.
1450 static int tty_reopen(struct tty_struct *tty)
1452 struct tty_driver *driver = tty->driver;
1454 if (test_bit(TTY_CLOSING, &tty->flags) ||
1455 test_bit(TTY_HUPPING, &tty->flags))
1458 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1459 driver->subtype == PTY_TYPE_MASTER) {
1461 * special case for PTY masters: only one open permitted,
1462 * and the slave side open count is incremented as well.
1471 WARN_ON(!tty->ldisc);
1477 * tty_init_dev - initialise a tty device
1478 * @driver: tty driver we are opening a device on
1479 * @idx: device index
1480 * @ret_tty: returned tty structure
1482 * Prepare a tty device. This may not be a "new" clean device but
1483 * could also be an active device. The pty drivers require special
1484 * handling because of this.
1487 * The function is called under the tty_mutex, which
1488 * protects us from the tty struct or driver itself going away.
1490 * On exit the tty device has the line discipline attached and
1491 * a reference count of 1. If a pair was created for pty/tty use
1492 * and the other was a pty master then it too has a reference count of 1.
1494 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1495 * failed open. The new code protects the open with a mutex, so it's
1496 * really quite straightforward. The mutex locking can probably be
1497 * relaxed for the (most common) case of reopening a tty.
1500 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1502 struct tty_struct *tty;
1506 * First time open is complex, especially for PTY devices.
1507 * This code guarantees that either everything succeeds and the
1508 * TTY is ready for operation, or else the table slots are vacated
1509 * and the allocated memory released. (Except that the termios
1510 * and locked termios may be retained.)
1513 if (!try_module_get(driver->owner))
1514 return ERR_PTR(-ENODEV);
1516 tty = alloc_tty_struct(driver, idx);
1519 goto err_module_put;
1523 retval = tty_driver_install_tty(driver, tty);
1525 goto err_deinit_tty;
1528 tty->port = driver->ports[idx];
1530 WARN_RATELIMIT(!tty->port,
1531 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1532 __func__, tty->driver->name);
1534 tty->port->itty = tty;
1537 * Structures all installed ... call the ldisc open routines.
1538 * If we fail here just call release_tty to clean up. No need
1539 * to decrement the use counts, as release_tty doesn't care.
1541 retval = tty_ldisc_setup(tty, tty->link);
1543 goto err_release_tty;
1544 /* Return the tty locked so that it cannot vanish under the caller */
1549 deinitialize_tty_struct(tty);
1550 free_tty_struct(tty);
1552 module_put(driver->owner);
1553 return ERR_PTR(retval);
1555 /* call the tty release_tty routine to clean out this slot */
1558 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1559 "clearing slot %d\n", idx);
1560 release_tty(tty, idx);
1561 return ERR_PTR(retval);
1564 void tty_free_termios(struct tty_struct *tty)
1566 struct ktermios *tp;
1567 int idx = tty->index;
1569 /* If the port is going to reset then it has no termios to save */
1570 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1573 /* Stash the termios data */
1574 tp = tty->driver->termios[idx];
1576 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1578 pr_warn("tty: no memory to save termios state.\n");
1581 tty->driver->termios[idx] = tp;
1585 EXPORT_SYMBOL(tty_free_termios);
1588 * tty_flush_works - flush all works of a tty
1589 * @tty: tty device to flush works for
1591 * Sync flush all works belonging to @tty.
1593 static void tty_flush_works(struct tty_struct *tty)
1595 flush_work(&tty->SAK_work);
1596 flush_work(&tty->hangup_work);
1600 * release_one_tty - release tty structure memory
1601 * @kref: kref of tty we are obliterating
1603 * Releases memory associated with a tty structure, and clears out the
1604 * driver table slots. This function is called when a device is no longer
1605 * in use. It also gets called when setup of a device fails.
1608 * takes the file list lock internally when working on the list
1609 * of ttys that the driver keeps.
1611 * This method gets called from a work queue so that the driver private
1612 * cleanup ops can sleep (needed for USB at least)
1614 static void release_one_tty(struct work_struct *work)
1616 struct tty_struct *tty =
1617 container_of(work, struct tty_struct, hangup_work);
1618 struct tty_driver *driver = tty->driver;
1619 struct module *owner = driver->owner;
1621 if (tty->ops->cleanup)
1622 tty->ops->cleanup(tty);
1625 tty_driver_kref_put(driver);
1628 spin_lock(&tty_files_lock);
1629 list_del_init(&tty->tty_files);
1630 spin_unlock(&tty_files_lock);
1633 put_pid(tty->session);
1634 free_tty_struct(tty);
1637 static void queue_release_one_tty(struct kref *kref)
1639 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1641 /* The hangup queue is now free so we can reuse it rather than
1642 waste a chunk of memory for each port */
1643 INIT_WORK(&tty->hangup_work, release_one_tty);
1644 schedule_work(&tty->hangup_work);
1648 * tty_kref_put - release a tty kref
1651 * Release a reference to a tty device and if need be let the kref
1652 * layer destruct the object for us
1655 void tty_kref_put(struct tty_struct *tty)
1658 kref_put(&tty->kref, queue_release_one_tty);
1660 EXPORT_SYMBOL(tty_kref_put);
1663 * release_tty - release tty structure memory
1665 * Release both @tty and a possible linked partner (think pty pair),
1666 * and decrement the refcount of the backing module.
1670 * takes the file list lock internally when working on the list
1671 * of ttys that the driver keeps.
1674 static void release_tty(struct tty_struct *tty, int idx)
1676 /* This should always be true but check for the moment */
1677 WARN_ON(tty->index != idx);
1678 WARN_ON(!mutex_is_locked(&tty_mutex));
1679 if (tty->ops->shutdown)
1680 tty->ops->shutdown(tty);
1681 tty_free_termios(tty);
1682 tty_driver_remove_tty(tty->driver, tty);
1683 tty->port->itty = NULL;
1685 tty->link->port->itty = NULL;
1686 cancel_work_sync(&tty->port->buf.work);
1689 tty_kref_put(tty->link);
1694 * tty_release_checks - check a tty before real release
1695 * @tty: tty to check
1696 * @o_tty: link of @tty (if any)
1697 * @idx: index of the tty
1699 * Performs some paranoid checking before true release of the @tty.
1700 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1702 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1705 #ifdef TTY_PARANOIA_CHECK
1706 if (idx < 0 || idx >= tty->driver->num) {
1707 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1708 __func__, tty->name);
1712 /* not much to check for devpts */
1713 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1716 if (tty != tty->driver->ttys[idx]) {
1717 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1718 __func__, idx, tty->name);
1721 if (tty->driver->other) {
1722 if (o_tty != tty->driver->other->ttys[idx]) {
1723 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1724 __func__, idx, tty->name);
1727 if (o_tty->link != tty) {
1728 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1737 * tty_release - vfs callback for close
1738 * @inode: inode of tty
1739 * @filp: file pointer for handle to tty
1741 * Called the last time each file handle is closed that references
1742 * this tty. There may however be several such references.
1745 * Takes bkl. See tty_release_dev
1747 * Even releasing the tty structures is a tricky business.. We have
1748 * to be very careful that the structures are all released at the
1749 * same time, as interrupts might otherwise get the wrong pointers.
1751 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1752 * lead to double frees or releasing memory still in use.
1755 int tty_release(struct inode *inode, struct file *filp)
1757 struct tty_struct *tty = file_tty(filp);
1758 struct tty_struct *o_tty;
1759 int pty_master, tty_closing, o_tty_closing, do_sleep;
1763 if (tty_paranoia_check(tty, inode, __func__))
1767 check_tty_count(tty, __func__);
1769 __tty_fasync(-1, filp, 0);
1772 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1773 tty->driver->subtype == PTY_TYPE_MASTER);
1774 /* Review: parallel close */
1777 if (tty_release_checks(tty, o_tty, idx)) {
1782 #ifdef TTY_DEBUG_HANGUP
1783 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1784 tty_name(tty, buf), tty->count);
1787 if (tty->ops->close)
1788 tty->ops->close(tty, filp);
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 closes,
1804 * Note that it's possible for the tty to be opened again while we're
1805 * flushing out waiters. By recalculating the closing flags before
1806 * each iteration we avoid any problems.
1809 /* Guard against races with tty->count changes elsewhere and
1810 opens on /dev/tty */
1812 mutex_lock(&tty_mutex);
1813 tty_lock_pair(tty, o_tty);
1814 tty_closing = tty->count <= 1;
1815 o_tty_closing = o_tty &&
1816 (o_tty->count <= (pty_master ? 1 : 0));
1820 if (waitqueue_active(&tty->read_wait)) {
1821 wake_up_poll(&tty->read_wait, POLLIN);
1824 if (waitqueue_active(&tty->write_wait)) {
1825 wake_up_poll(&tty->write_wait, POLLOUT);
1829 if (o_tty_closing) {
1830 if (waitqueue_active(&o_tty->read_wait)) {
1831 wake_up_poll(&o_tty->read_wait, POLLIN);
1834 if (waitqueue_active(&o_tty->write_wait)) {
1835 wake_up_poll(&o_tty->write_wait, POLLOUT);
1842 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1843 __func__, tty_name(tty, buf));
1844 tty_unlock_pair(tty, o_tty);
1845 mutex_unlock(&tty_mutex);
1850 * The closing flags are now consistent with the open counts on
1851 * both sides, and we've completed the last operation that could
1852 * block, so it's safe to proceed with closing.
1854 * We must *not* drop the tty_mutex until we ensure that a further
1855 * entry into tty_open can not pick up this tty.
1858 if (--o_tty->count < 0) {
1859 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1860 __func__, o_tty->count, tty_name(o_tty, buf));
1864 if (--tty->count < 0) {
1865 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1866 __func__, tty->count, tty_name(tty, buf));
1871 * We've decremented tty->count, so we need to remove this file
1872 * descriptor off the tty->tty_files list; this serves two
1874 * - check_tty_count sees the correct number of file descriptors
1875 * associated with this tty.
1876 * - do_tty_hangup no longer sees this file descriptor as
1877 * something that needs to be handled for hangups.
1882 * Perform some housekeeping before deciding whether to return.
1884 * Set the TTY_CLOSING flag if this was the last open. In the
1885 * case of a pty we may have to wait around for the other side
1886 * to close, and TTY_CLOSING makes sure we can't be reopened.
1889 set_bit(TTY_CLOSING, &tty->flags);
1891 set_bit(TTY_CLOSING, &o_tty->flags);
1894 * If _either_ side is closing, make sure there aren't any
1895 * processes that still think tty or o_tty is their controlling
1898 if (tty_closing || o_tty_closing) {
1899 read_lock(&tasklist_lock);
1900 session_clear_tty(tty->session);
1902 session_clear_tty(o_tty->session);
1903 read_unlock(&tasklist_lock);
1906 mutex_unlock(&tty_mutex);
1907 tty_unlock_pair(tty, o_tty);
1908 /* At this point the TTY_CLOSING flag should ensure a dead tty
1909 cannot be re-opened by a racing opener */
1911 /* check whether both sides are closing ... */
1912 if (!tty_closing || (o_tty && !o_tty_closing))
1915 #ifdef TTY_DEBUG_HANGUP
1916 printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
1919 * Ask the line discipline code to release its structures
1921 tty_ldisc_release(tty, o_tty);
1923 /* Wait for pending work before tty destruction commmences */
1924 tty_flush_works(tty);
1926 tty_flush_works(o_tty);
1928 #ifdef TTY_DEBUG_HANGUP
1929 printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
1932 * The release_tty function takes care of the details of clearing
1933 * the slots and preserving the termios structure. The tty_unlock_pair
1934 * should be safe as we keep a kref while the tty is locked (so the
1935 * unlock never unlocks a freed tty).
1937 mutex_lock(&tty_mutex);
1938 release_tty(tty, idx);
1939 mutex_unlock(&tty_mutex);
1945 * tty_open_current_tty - get tty of current task for open
1946 * @device: device number
1947 * @filp: file pointer to tty
1948 * @return: tty of the current task iff @device is /dev/tty
1950 * We cannot return driver and index like for the other nodes because
1951 * devpts will not work then. It expects inodes to be from devpts FS.
1953 * We need to move to returning a refcounted object from all the lookup
1954 * paths including this one.
1956 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1958 struct tty_struct *tty;
1960 if (device != MKDEV(TTYAUX_MAJOR, 0))
1963 tty = get_current_tty();
1965 return ERR_PTR(-ENXIO);
1967 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1970 /* FIXME: we put a reference and return a TTY! */
1971 /* This is only safe because the caller holds tty_mutex */
1976 * tty_lookup_driver - lookup a tty driver for a given device file
1977 * @device: device number
1978 * @filp: file pointer to tty
1979 * @noctty: set if the device should not become a controlling tty
1980 * @index: index for the device in the @return driver
1981 * @return: driver for this inode (with increased refcount)
1983 * If @return is not erroneous, the caller is responsible to decrement the
1984 * refcount by tty_driver_kref_put.
1986 * Locking: tty_mutex protects get_tty_driver
1988 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1989 int *noctty, int *index)
1991 struct tty_driver *driver;
1995 case MKDEV(TTY_MAJOR, 0): {
1996 extern struct tty_driver *console_driver;
1997 driver = tty_driver_kref_get(console_driver);
1998 *index = fg_console;
2003 case MKDEV(TTYAUX_MAJOR, 1): {
2004 struct tty_driver *console_driver = console_device(index);
2005 if (console_driver) {
2006 driver = tty_driver_kref_get(console_driver);
2008 /* Don't let /dev/console block */
2009 filp->f_flags |= O_NONBLOCK;
2014 return ERR_PTR(-ENODEV);
2017 driver = get_tty_driver(device, index);
2019 return ERR_PTR(-ENODEV);
2026 * tty_open - open a tty device
2027 * @inode: inode of device file
2028 * @filp: file pointer to tty
2030 * tty_open and tty_release keep up the tty count that contains the
2031 * number of opens done on a tty. We cannot use the inode-count, as
2032 * different inodes might point to the same tty.
2034 * Open-counting is needed for pty masters, as well as for keeping
2035 * track of serial lines: DTR is dropped when the last close happens.
2036 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2038 * The termios state of a pty is reset on first open so that
2039 * settings don't persist across reuse.
2041 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2042 * tty->count should protect the rest.
2043 * ->siglock protects ->signal/->sighand
2045 * Note: the tty_unlock/lock cases without a ref are only safe due to
2049 static int tty_open(struct inode *inode, struct file *filp)
2051 struct tty_struct *tty;
2053 struct tty_driver *driver = NULL;
2055 dev_t device = inode->i_rdev;
2056 unsigned saved_flags = filp->f_flags;
2058 nonseekable_open(inode, filp);
2061 retval = tty_alloc_file(filp);
2065 noctty = filp->f_flags & O_NOCTTY;
2069 mutex_lock(&tty_mutex);
2070 /* This is protected by the tty_mutex */
2071 tty = tty_open_current_tty(device, filp);
2073 retval = PTR_ERR(tty);
2076 driver = tty_lookup_driver(device, filp, &noctty, &index);
2077 if (IS_ERR(driver)) {
2078 retval = PTR_ERR(driver);
2082 /* check whether we're reopening an existing tty */
2083 tty = tty_driver_lookup_tty(driver, inode, index);
2085 retval = PTR_ERR(tty);
2092 retval = tty_reopen(tty);
2095 tty = ERR_PTR(retval);
2097 } else /* Returns with the tty_lock held for now */
2098 tty = tty_init_dev(driver, index);
2100 mutex_unlock(&tty_mutex);
2102 tty_driver_kref_put(driver);
2104 retval = PTR_ERR(tty);
2108 tty_add_file(tty, filp);
2110 check_tty_count(tty, __func__);
2111 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2112 tty->driver->subtype == PTY_TYPE_MASTER)
2114 #ifdef TTY_DEBUG_HANGUP
2115 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
2118 retval = tty->ops->open(tty, filp);
2121 filp->f_flags = saved_flags;
2123 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
2124 !capable(CAP_SYS_ADMIN))
2128 #ifdef TTY_DEBUG_HANGUP
2129 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
2132 tty_unlock(tty); /* need to call tty_release without BTM */
2133 tty_release(inode, filp);
2134 if (retval != -ERESTARTSYS)
2137 if (signal_pending(current))
2142 * Need to reset f_op in case a hangup happened.
2144 if (filp->f_op == &hung_up_tty_fops)
2145 filp->f_op = &tty_fops;
2148 clear_bit(TTY_HUPPED, &tty->flags);
2152 mutex_lock(&tty_mutex);
2154 spin_lock_irq(¤t->sighand->siglock);
2156 current->signal->leader &&
2157 !current->signal->tty &&
2158 tty->session == NULL)
2159 __proc_set_tty(tty);
2160 spin_unlock_irq(¤t->sighand->siglock);
2162 mutex_unlock(&tty_mutex);
2165 mutex_unlock(&tty_mutex);
2166 /* after locks to avoid deadlock */
2167 if (!IS_ERR_OR_NULL(driver))
2168 tty_driver_kref_put(driver);
2170 tty_free_file(filp);
2177 * tty_poll - check tty status
2178 * @filp: file being polled
2179 * @wait: poll wait structures to update
2181 * Call the line discipline polling method to obtain the poll
2182 * status of the device.
2184 * Locking: locks called line discipline but ldisc poll method
2185 * may be re-entered freely by other callers.
2188 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2190 struct tty_struct *tty = file_tty(filp);
2191 struct tty_ldisc *ld;
2194 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2197 ld = tty_ldisc_ref_wait(tty);
2199 ret = (ld->ops->poll)(tty, filp, wait);
2200 tty_ldisc_deref(ld);
2204 static int __tty_fasync(int fd, struct file *filp, int on)
2206 struct tty_struct *tty = file_tty(filp);
2207 struct tty_ldisc *ldisc;
2208 unsigned long flags;
2211 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2214 retval = fasync_helper(fd, filp, on, &tty->fasync);
2218 ldisc = tty_ldisc_ref(tty);
2220 if (ldisc->ops->fasync)
2221 ldisc->ops->fasync(tty, on);
2222 tty_ldisc_deref(ldisc);
2229 spin_lock_irqsave(&tty->ctrl_lock, flags);
2232 type = PIDTYPE_PGID;
2234 pid = task_pid(current);
2238 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2239 __f_setown(filp, pid, type, 0);
2247 static int tty_fasync(int fd, struct file *filp, int on)
2249 struct tty_struct *tty = file_tty(filp);
2253 retval = __tty_fasync(fd, filp, on);
2260 * tiocsti - fake input character
2261 * @tty: tty to fake input into
2262 * @p: pointer to character
2264 * Fake input to a tty device. Does the necessary locking and
2267 * FIXME: does not honour flow control ??
2270 * Called functions take tty_ldiscs_lock
2271 * current->signal->tty check is safe without locks
2273 * FIXME: may race normal receive processing
2276 static int tiocsti(struct tty_struct *tty, char __user *p)
2279 struct tty_ldisc *ld;
2281 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2283 if (get_user(ch, p))
2285 tty_audit_tiocsti(tty, ch);
2286 ld = tty_ldisc_ref_wait(tty);
2287 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2288 tty_ldisc_deref(ld);
2293 * tiocgwinsz - implement window query ioctl
2295 * @arg: user buffer for result
2297 * Copies the kernel idea of the window size into the user buffer.
2299 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2303 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2307 mutex_lock(&tty->winsize_mutex);
2308 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2309 mutex_unlock(&tty->winsize_mutex);
2311 return err ? -EFAULT: 0;
2315 * tty_do_resize - resize event
2316 * @tty: tty being resized
2317 * @rows: rows (character)
2318 * @cols: cols (character)
2320 * Update the termios variables and send the necessary signals to
2321 * peform a terminal resize correctly
2324 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2327 unsigned long flags;
2330 mutex_lock(&tty->winsize_mutex);
2331 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2333 /* Get the PID values and reference them so we can
2334 avoid holding the tty ctrl lock while sending signals */
2335 spin_lock_irqsave(&tty->ctrl_lock, flags);
2336 pgrp = get_pid(tty->pgrp);
2337 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2340 kill_pgrp(pgrp, SIGWINCH, 1);
2345 mutex_unlock(&tty->winsize_mutex);
2348 EXPORT_SYMBOL(tty_do_resize);
2351 * tiocswinsz - implement window size set ioctl
2352 * @tty; tty side of tty
2353 * @arg: user buffer for result
2355 * Copies the user idea of the window size to the kernel. Traditionally
2356 * this is just advisory information but for the Linux console it
2357 * actually has driver level meaning and triggers a VC resize.
2360 * Driver dependent. The default do_resize method takes the
2361 * tty termios mutex and ctrl_lock. The console takes its own lock
2362 * then calls into the default method.
2365 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2367 struct winsize tmp_ws;
2368 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2371 if (tty->ops->resize)
2372 return tty->ops->resize(tty, &tmp_ws);
2374 return tty_do_resize(tty, &tmp_ws);
2378 * tioccons - allow admin to move logical console
2379 * @file: the file to become console
2381 * Allow the administrator to move the redirected console device
2383 * Locking: uses redirect_lock to guard the redirect information
2386 static int tioccons(struct file *file)
2388 if (!capable(CAP_SYS_ADMIN))
2390 if (file->f_op->write == redirected_tty_write) {
2392 spin_lock(&redirect_lock);
2395 spin_unlock(&redirect_lock);
2400 spin_lock(&redirect_lock);
2402 spin_unlock(&redirect_lock);
2405 redirect = get_file(file);
2406 spin_unlock(&redirect_lock);
2411 * fionbio - non blocking ioctl
2412 * @file: file to set blocking value
2413 * @p: user parameter
2415 * Historical tty interfaces had a blocking control ioctl before
2416 * the generic functionality existed. This piece of history is preserved
2417 * in the expected tty API of posix OS's.
2419 * Locking: none, the open file handle ensures it won't go away.
2422 static int fionbio(struct file *file, int __user *p)
2426 if (get_user(nonblock, p))
2429 spin_lock(&file->f_lock);
2431 file->f_flags |= O_NONBLOCK;
2433 file->f_flags &= ~O_NONBLOCK;
2434 spin_unlock(&file->f_lock);
2439 * tiocsctty - set controlling tty
2440 * @tty: tty structure
2441 * @arg: user argument
2443 * This ioctl is used to manage job control. It permits a session
2444 * leader to set this tty as the controlling tty for the session.
2447 * Takes tty_mutex() to protect tty instance
2448 * Takes tasklist_lock internally to walk sessions
2449 * Takes ->siglock() when updating signal->tty
2452 static int tiocsctty(struct tty_struct *tty, int arg)
2455 if (current->signal->leader && (task_session(current) == tty->session))
2458 mutex_lock(&tty_mutex);
2460 * The process must be a session leader and
2461 * not have a controlling tty already.
2463 if (!current->signal->leader || current->signal->tty) {
2470 * This tty is already the controlling
2471 * tty for another session group!
2473 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2477 read_lock(&tasklist_lock);
2478 session_clear_tty(tty->session);
2479 read_unlock(&tasklist_lock);
2487 mutex_unlock(&tty_mutex);
2492 * tty_get_pgrp - return a ref counted pgrp pid
2495 * Returns a refcounted instance of the pid struct for the process
2496 * group controlling the tty.
2499 struct pid *tty_get_pgrp(struct tty_struct *tty)
2501 unsigned long flags;
2504 spin_lock_irqsave(&tty->ctrl_lock, flags);
2505 pgrp = get_pid(tty->pgrp);
2506 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2510 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2513 * tiocgpgrp - get process group
2514 * @tty: tty passed by user
2515 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2518 * Obtain the process group of the tty. If there is no process group
2521 * Locking: none. Reference to current->signal->tty is safe.
2524 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2529 * (tty == real_tty) is a cheap way of
2530 * testing if the tty is NOT a master pty.
2532 if (tty == real_tty && current->signal->tty != real_tty)
2534 pid = tty_get_pgrp(real_tty);
2535 ret = put_user(pid_vnr(pid), p);
2541 * tiocspgrp - attempt to set process group
2542 * @tty: tty passed by user
2543 * @real_tty: tty side device matching tty passed by user
2546 * Set the process group of the tty to the session passed. Only
2547 * permitted where the tty session is our session.
2549 * Locking: RCU, ctrl lock
2552 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2556 int retval = tty_check_change(real_tty);
2557 unsigned long flags;
2563 if (!current->signal->tty ||
2564 (current->signal->tty != real_tty) ||
2565 (real_tty->session != task_session(current)))
2567 if (get_user(pgrp_nr, p))
2572 pgrp = find_vpid(pgrp_nr);
2577 if (session_of_pgrp(pgrp) != task_session(current))
2580 spin_lock_irqsave(&tty->ctrl_lock, flags);
2581 put_pid(real_tty->pgrp);
2582 real_tty->pgrp = get_pid(pgrp);
2583 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2590 * tiocgsid - get session id
2591 * @tty: tty passed by user
2592 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2593 * @p: pointer to returned session id
2595 * Obtain the session id of the tty. If there is no session
2598 * Locking: none. Reference to current->signal->tty is safe.
2601 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2604 * (tty == real_tty) is a cheap way of
2605 * testing if the tty is NOT a master pty.
2607 if (tty == real_tty && current->signal->tty != real_tty)
2609 if (!real_tty->session)
2611 return put_user(pid_vnr(real_tty->session), p);
2615 * tiocsetd - set line discipline
2617 * @p: pointer to user data
2619 * Set the line discipline according to user request.
2621 * Locking: see tty_set_ldisc, this function is just a helper
2624 static int tiocsetd(struct tty_struct *tty, int __user *p)
2629 if (get_user(ldisc, p))
2632 ret = tty_set_ldisc(tty, ldisc);
2638 * send_break - performed time break
2639 * @tty: device to break on
2640 * @duration: timeout in mS
2642 * Perform a timed break on hardware that lacks its own driver level
2643 * timed break functionality.
2646 * atomic_write_lock serializes
2650 static int send_break(struct tty_struct *tty, unsigned int duration)
2654 if (tty->ops->break_ctl == NULL)
2657 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2658 retval = tty->ops->break_ctl(tty, duration);
2660 /* Do the work ourselves */
2661 if (tty_write_lock(tty, 0) < 0)
2663 retval = tty->ops->break_ctl(tty, -1);
2666 if (!signal_pending(current))
2667 msleep_interruptible(duration);
2668 retval = tty->ops->break_ctl(tty, 0);
2670 tty_write_unlock(tty);
2671 if (signal_pending(current))
2678 * tty_tiocmget - get modem status
2680 * @file: user file pointer
2681 * @p: pointer to result
2683 * Obtain the modem status bits from the tty driver if the feature
2684 * is supported. Return -EINVAL if it is not available.
2686 * Locking: none (up to the driver)
2689 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2691 int retval = -EINVAL;
2693 if (tty->ops->tiocmget) {
2694 retval = tty->ops->tiocmget(tty);
2697 retval = put_user(retval, p);
2703 * tty_tiocmset - set modem status
2705 * @cmd: command - clear bits, set bits or set all
2706 * @p: pointer to desired bits
2708 * Set the modem status bits from the tty driver if the feature
2709 * is supported. Return -EINVAL if it is not available.
2711 * Locking: none (up to the driver)
2714 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2718 unsigned int set, clear, val;
2720 if (tty->ops->tiocmset == NULL)
2723 retval = get_user(val, p);
2739 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2740 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2741 return tty->ops->tiocmset(tty, set, clear);
2744 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2746 int retval = -EINVAL;
2747 struct serial_icounter_struct icount;
2748 memset(&icount, 0, sizeof(icount));
2749 if (tty->ops->get_icount)
2750 retval = tty->ops->get_icount(tty, &icount);
2753 if (copy_to_user(arg, &icount, sizeof(icount)))
2759 * if pty, return the slave side (real_tty)
2760 * otherwise, return self
2762 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2764 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2765 tty->driver->subtype == PTY_TYPE_MASTER)
2771 * Split this up, as gcc can choke on it otherwise..
2773 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2775 struct tty_struct *tty = file_tty(file);
2776 struct tty_struct *real_tty;
2777 void __user *p = (void __user *)arg;
2779 struct tty_ldisc *ld;
2781 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2784 real_tty = tty_pair_get_tty(tty);
2787 * Factor out some common prep work
2795 retval = tty_check_change(tty);
2798 if (cmd != TIOCCBRK) {
2799 tty_wait_until_sent(tty, 0);
2800 if (signal_pending(current))
2811 return tiocsti(tty, p);
2813 return tiocgwinsz(real_tty, p);
2815 return tiocswinsz(real_tty, p);
2817 return real_tty != tty ? -EINVAL : tioccons(file);
2819 return fionbio(file, p);
2821 set_bit(TTY_EXCLUSIVE, &tty->flags);
2824 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2828 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2829 return put_user(excl, (int __user *)p);
2832 if (current->signal->tty != tty)
2837 return tiocsctty(tty, arg);
2839 return tiocgpgrp(tty, real_tty, p);
2841 return tiocspgrp(tty, real_tty, p);
2843 return tiocgsid(tty, real_tty, p);
2845 return put_user(tty->ldisc->ops->num, (int __user *)p);
2847 return tiocsetd(tty, p);
2849 if (!capable(CAP_SYS_ADMIN))
2855 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2856 return put_user(ret, (unsigned int __user *)p);
2861 case TIOCSBRK: /* Turn break on, unconditionally */
2862 if (tty->ops->break_ctl)
2863 return tty->ops->break_ctl(tty, -1);
2865 case TIOCCBRK: /* Turn break off, unconditionally */
2866 if (tty->ops->break_ctl)
2867 return tty->ops->break_ctl(tty, 0);
2869 case TCSBRK: /* SVID version: non-zero arg --> no break */
2870 /* non-zero arg means wait for all output data
2871 * to be sent (performed above) but don't send break.
2872 * This is used by the tcdrain() termios function.
2875 return send_break(tty, 250);
2877 case TCSBRKP: /* support for POSIX tcsendbreak() */
2878 return send_break(tty, arg ? arg*100 : 250);
2881 return tty_tiocmget(tty, p);
2885 return tty_tiocmset(tty, cmd, p);
2887 retval = tty_tiocgicount(tty, p);
2888 /* For the moment allow fall through to the old method */
2889 if (retval != -EINVAL)
2896 /* flush tty buffer and allow ldisc to process ioctl */
2897 tty_buffer_flush(tty);
2902 if (tty->ops->ioctl) {
2903 retval = (tty->ops->ioctl)(tty, cmd, arg);
2904 if (retval != -ENOIOCTLCMD)
2907 ld = tty_ldisc_ref_wait(tty);
2909 if (ld->ops->ioctl) {
2910 retval = ld->ops->ioctl(tty, file, cmd, arg);
2911 if (retval == -ENOIOCTLCMD)
2914 tty_ldisc_deref(ld);
2918 #ifdef CONFIG_COMPAT
2919 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2922 struct tty_struct *tty = file_tty(file);
2923 struct tty_ldisc *ld;
2924 int retval = -ENOIOCTLCMD;
2926 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2929 if (tty->ops->compat_ioctl) {
2930 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2931 if (retval != -ENOIOCTLCMD)
2935 ld = tty_ldisc_ref_wait(tty);
2936 if (ld->ops->compat_ioctl)
2937 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2939 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2940 tty_ldisc_deref(ld);
2946 static int this_tty(const void *t, struct file *file, unsigned fd)
2948 if (likely(file->f_op->read != tty_read))
2950 return file_tty(file) != t ? 0 : fd + 1;
2954 * This implements the "Secure Attention Key" --- the idea is to
2955 * prevent trojan horses by killing all processes associated with this
2956 * tty when the user hits the "Secure Attention Key". Required for
2957 * super-paranoid applications --- see the Orange Book for more details.
2959 * This code could be nicer; ideally it should send a HUP, wait a few
2960 * seconds, then send a INT, and then a KILL signal. But you then
2961 * have to coordinate with the init process, since all processes associated
2962 * with the current tty must be dead before the new getty is allowed
2965 * Now, if it would be correct ;-/ The current code has a nasty hole -
2966 * it doesn't catch files in flight. We may send the descriptor to ourselves
2967 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2969 * Nasty bug: do_SAK is being called in interrupt context. This can
2970 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2972 void __do_SAK(struct tty_struct *tty)
2977 struct task_struct *g, *p;
2978 struct pid *session;
2983 session = tty->session;
2985 tty_ldisc_flush(tty);
2987 tty_driver_flush_buffer(tty);
2989 read_lock(&tasklist_lock);
2990 /* Kill the entire session */
2991 do_each_pid_task(session, PIDTYPE_SID, p) {
2992 printk(KERN_NOTICE "SAK: killed process %d"
2993 " (%s): task_session(p)==tty->session\n",
2994 task_pid_nr(p), p->comm);
2995 send_sig(SIGKILL, p, 1);
2996 } while_each_pid_task(session, PIDTYPE_SID, p);
2997 /* Now kill any processes that happen to have the
3000 do_each_thread(g, p) {
3001 if (p->signal->tty == tty) {
3002 printk(KERN_NOTICE "SAK: killed process %d"
3003 " (%s): task_session(p)==tty->session\n",
3004 task_pid_nr(p), p->comm);
3005 send_sig(SIGKILL, p, 1);
3009 i = iterate_fd(p->files, 0, this_tty, tty);
3011 printk(KERN_NOTICE "SAK: killed process %d"
3012 " (%s): fd#%d opened to the tty\n",
3013 task_pid_nr(p), p->comm, i - 1);
3014 force_sig(SIGKILL, p);
3017 } while_each_thread(g, p);
3018 read_unlock(&tasklist_lock);
3022 static void do_SAK_work(struct work_struct *work)
3024 struct tty_struct *tty =
3025 container_of(work, struct tty_struct, SAK_work);
3030 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3031 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3032 * the values which we write to it will be identical to the values which it
3033 * already has. --akpm
3035 void do_SAK(struct tty_struct *tty)
3039 schedule_work(&tty->SAK_work);
3042 EXPORT_SYMBOL(do_SAK);
3044 static int dev_match_devt(struct device *dev, const void *data)
3046 const dev_t *devt = data;
3047 return dev->devt == *devt;
3050 /* Must put_device() after it's unused! */
3051 static struct device *tty_get_device(struct tty_struct *tty)
3053 dev_t devt = tty_devnum(tty);
3054 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3061 * This subroutine allocates and initializes a tty structure.
3063 * Locking: none - tty in question is not exposed at this point
3066 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3068 struct tty_struct *tty;
3070 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3074 kref_init(&tty->kref);
3075 tty->magic = TTY_MAGIC;
3076 tty_ldisc_init(tty);
3077 tty->session = NULL;
3079 mutex_init(&tty->legacy_mutex);
3080 mutex_init(&tty->throttle_mutex);
3081 init_rwsem(&tty->termios_rwsem);
3082 mutex_init(&tty->winsize_mutex);
3083 init_ldsem(&tty->ldisc_sem);
3084 init_waitqueue_head(&tty->write_wait);
3085 init_waitqueue_head(&tty->read_wait);
3086 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3087 mutex_init(&tty->atomic_write_lock);
3088 spin_lock_init(&tty->ctrl_lock);
3089 spin_lock_init(&tty->flow_lock);
3090 INIT_LIST_HEAD(&tty->tty_files);
3091 INIT_WORK(&tty->SAK_work, do_SAK_work);
3093 tty->driver = driver;
3094 tty->ops = driver->ops;
3096 tty_line_name(driver, idx, tty->name);
3097 tty->dev = tty_get_device(tty);
3103 * deinitialize_tty_struct
3104 * @tty: tty to deinitialize
3106 * This subroutine deinitializes a tty structure that has been newly
3107 * allocated but tty_release cannot be called on that yet.
3109 * Locking: none - tty in question must not be exposed at this point
3111 void deinitialize_tty_struct(struct tty_struct *tty)
3113 tty_ldisc_deinit(tty);
3117 * tty_put_char - write one character to a tty
3121 * Write one byte to the tty using the provided put_char method
3122 * if present. Returns the number of characters successfully output.
3124 * Note: the specific put_char operation in the driver layer may go
3125 * away soon. Don't call it directly, use this method
3128 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3130 if (tty->ops->put_char)
3131 return tty->ops->put_char(tty, ch);
3132 return tty->ops->write(tty, &ch, 1);
3134 EXPORT_SYMBOL_GPL(tty_put_char);
3136 struct class *tty_class;
3138 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3139 unsigned int index, unsigned int count)
3141 /* init here, since reused cdevs cause crashes */
3142 cdev_init(&driver->cdevs[index], &tty_fops);
3143 driver->cdevs[index].owner = driver->owner;
3144 return cdev_add(&driver->cdevs[index], dev, count);
3148 * tty_register_device - register a tty device
3149 * @driver: the tty driver that describes the tty device
3150 * @index: the index in the tty driver for this tty device
3151 * @device: a struct device that is associated with this tty device.
3152 * This field is optional, if there is no known struct device
3153 * for this tty device it can be set to NULL safely.
3155 * Returns a pointer to the struct device for this tty device
3156 * (or ERR_PTR(-EFOO) on error).
3158 * This call is required to be made to register an individual tty device
3159 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3160 * that bit is not set, this function should not be called by a tty
3166 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3167 struct device *device)
3169 return tty_register_device_attr(driver, index, device, NULL, NULL);
3171 EXPORT_SYMBOL(tty_register_device);
3173 static void tty_device_create_release(struct device *dev)
3175 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3180 * tty_register_device_attr - register a tty device
3181 * @driver: the tty driver that describes the tty device
3182 * @index: the index in the tty driver for this tty device
3183 * @device: a struct device that is associated with this tty device.
3184 * This field is optional, if there is no known struct device
3185 * for this tty device it can be set to NULL safely.
3186 * @drvdata: Driver data to be set to device.
3187 * @attr_grp: Attribute group to be set on device.
3189 * Returns a pointer to the struct device for this tty device
3190 * (or ERR_PTR(-EFOO) on error).
3192 * This call is required to be made to register an individual tty device
3193 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3194 * that bit is not set, this function should not be called by a tty
3199 struct device *tty_register_device_attr(struct tty_driver *driver,
3200 unsigned index, struct device *device,
3202 const struct attribute_group **attr_grp)
3205 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3206 struct device *dev = NULL;
3207 int retval = -ENODEV;
3210 if (index >= driver->num) {
3211 printk(KERN_ERR "Attempt to register invalid tty line number "
3213 return ERR_PTR(-EINVAL);
3216 if (driver->type == TTY_DRIVER_TYPE_PTY)
3217 pty_line_name(driver, index, name);
3219 tty_line_name(driver, index, name);
3221 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3222 retval = tty_cdev_add(driver, devt, index, 1);
3228 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3235 dev->class = tty_class;
3236 dev->parent = device;
3237 dev->release = tty_device_create_release;
3238 dev_set_name(dev, "%s", name);
3239 dev->groups = attr_grp;
3240 dev_set_drvdata(dev, drvdata);
3242 retval = device_register(dev);
3251 cdev_del(&driver->cdevs[index]);
3252 return ERR_PTR(retval);
3254 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3257 * tty_unregister_device - unregister a tty device
3258 * @driver: the tty driver that describes the tty device
3259 * @index: the index in the tty driver for this tty device
3261 * If a tty device is registered with a call to tty_register_device() then
3262 * this function must be called when the tty device is gone.
3267 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3269 device_destroy(tty_class,
3270 MKDEV(driver->major, driver->minor_start) + index);
3271 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3272 cdev_del(&driver->cdevs[index]);
3274 EXPORT_SYMBOL(tty_unregister_device);
3277 * __tty_alloc_driver -- allocate tty driver
3278 * @lines: count of lines this driver can handle at most
3279 * @owner: module which is repsonsible for this driver
3280 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3282 * This should not be called directly, some of the provided macros should be
3283 * used instead. Use IS_ERR and friends on @retval.
3285 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3286 unsigned long flags)
3288 struct tty_driver *driver;
3289 unsigned int cdevs = 1;
3292 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3293 return ERR_PTR(-EINVAL);
3295 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3297 return ERR_PTR(-ENOMEM);
3299 kref_init(&driver->kref);
3300 driver->magic = TTY_DRIVER_MAGIC;
3301 driver->num = lines;
3302 driver->owner = owner;
3303 driver->flags = flags;
3305 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3306 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3308 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3310 if (!driver->ttys || !driver->termios) {
3316 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3317 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3319 if (!driver->ports) {
3326 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3327 if (!driver->cdevs) {
3334 kfree(driver->ports);
3335 kfree(driver->ttys);
3336 kfree(driver->termios);
3338 return ERR_PTR(err);
3340 EXPORT_SYMBOL(__tty_alloc_driver);
3342 static void destruct_tty_driver(struct kref *kref)
3344 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3346 struct ktermios *tp;
3348 if (driver->flags & TTY_DRIVER_INSTALLED) {
3350 * Free the termios and termios_locked structures because
3351 * we don't want to get memory leaks when modular tty
3352 * drivers are removed from the kernel.
3354 for (i = 0; i < driver->num; i++) {
3355 tp = driver->termios[i];
3357 driver->termios[i] = NULL;
3360 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3361 tty_unregister_device(driver, i);
3363 proc_tty_unregister_driver(driver);
3364 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3365 cdev_del(&driver->cdevs[0]);
3367 kfree(driver->cdevs);
3368 kfree(driver->ports);
3369 kfree(driver->termios);
3370 kfree(driver->ttys);
3374 void tty_driver_kref_put(struct tty_driver *driver)
3376 kref_put(&driver->kref, destruct_tty_driver);
3378 EXPORT_SYMBOL(tty_driver_kref_put);
3380 void tty_set_operations(struct tty_driver *driver,
3381 const struct tty_operations *op)
3385 EXPORT_SYMBOL(tty_set_operations);
3387 void put_tty_driver(struct tty_driver *d)
3389 tty_driver_kref_put(d);
3391 EXPORT_SYMBOL(put_tty_driver);
3394 * Called by a tty driver to register itself.
3396 int tty_register_driver(struct tty_driver *driver)
3403 if (!driver->major) {
3404 error = alloc_chrdev_region(&dev, driver->minor_start,
3405 driver->num, driver->name);
3407 driver->major = MAJOR(dev);
3408 driver->minor_start = MINOR(dev);
3411 dev = MKDEV(driver->major, driver->minor_start);
3412 error = register_chrdev_region(dev, driver->num, driver->name);
3417 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3418 error = tty_cdev_add(driver, dev, 0, driver->num);
3420 goto err_unreg_char;
3423 mutex_lock(&tty_mutex);
3424 list_add(&driver->tty_drivers, &tty_drivers);
3425 mutex_unlock(&tty_mutex);
3427 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3428 for (i = 0; i < driver->num; i++) {
3429 d = tty_register_device(driver, i, NULL);
3432 goto err_unreg_devs;
3436 proc_tty_register_driver(driver);
3437 driver->flags |= TTY_DRIVER_INSTALLED;
3441 for (i--; i >= 0; i--)
3442 tty_unregister_device(driver, i);
3444 mutex_lock(&tty_mutex);
3445 list_del(&driver->tty_drivers);
3446 mutex_unlock(&tty_mutex);
3449 unregister_chrdev_region(dev, driver->num);
3453 EXPORT_SYMBOL(tty_register_driver);
3456 * Called by a tty driver to unregister itself.
3458 int tty_unregister_driver(struct tty_driver *driver)
3462 if (driver->refcount)
3465 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3467 mutex_lock(&tty_mutex);
3468 list_del(&driver->tty_drivers);
3469 mutex_unlock(&tty_mutex);
3473 EXPORT_SYMBOL(tty_unregister_driver);
3475 dev_t tty_devnum(struct tty_struct *tty)
3477 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3479 EXPORT_SYMBOL(tty_devnum);
3481 void tty_default_fops(struct file_operations *fops)
3487 * Initialize the console device. This is called *early*, so
3488 * we can't necessarily depend on lots of kernel help here.
3489 * Just do some early initializations, and do the complex setup
3492 void __init console_init(void)
3496 /* Setup the default TTY line discipline. */
3500 * set up the console device so that later boot sequences can
3501 * inform about problems etc..
3503 call = __con_initcall_start;
3504 while (call < __con_initcall_end) {
3510 static char *tty_devnode(struct device *dev, umode_t *mode)
3514 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3515 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3520 static int __init tty_class_init(void)
3522 tty_class = class_create(THIS_MODULE, "tty");
3523 if (IS_ERR(tty_class))
3524 return PTR_ERR(tty_class);
3525 tty_class->devnode = tty_devnode;
3529 postcore_initcall(tty_class_init);
3531 /* 3/2004 jmc: why do these devices exist? */
3532 static struct cdev tty_cdev, console_cdev;
3534 static ssize_t show_cons_active(struct device *dev,
3535 struct device_attribute *attr, char *buf)
3537 struct console *cs[16];
3543 for_each_console(c) {
3548 if ((c->flags & CON_ENABLED) == 0)
3551 if (i >= ARRAY_SIZE(cs))
3555 int index = cs[i]->index;
3556 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3558 /* don't resolve tty0 as some programs depend on it */
3559 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3560 count += tty_line_name(drv, index, buf + count);
3562 count += sprintf(buf + count, "%s%d",
3563 cs[i]->name, cs[i]->index);
3565 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3571 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3573 static struct device *consdev;
3575 void console_sysfs_notify(void)
3578 sysfs_notify(&consdev->kobj, NULL, "active");
3582 * Ok, now we can initialize the rest of the tty devices and can count
3583 * on memory allocations, interrupts etc..
3585 int __init tty_init(void)
3587 cdev_init(&tty_cdev, &tty_fops);
3588 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3589 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3590 panic("Couldn't register /dev/tty driver\n");
3591 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3593 cdev_init(&console_cdev, &console_fops);
3594 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3595 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3596 panic("Couldn't register /dev/console driver\n");
3597 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3599 if (IS_ERR(consdev))
3602 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3605 vty_init(&console_fops);