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);
156 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
157 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
160 * free_tty_struct - free a disused tty
161 * @tty: tty struct to free
163 * Free the write buffers, tty queue and tty memory itself.
165 * Locking: none. Must be called after tty is definitely unused
168 void free_tty_struct(struct tty_struct *tty)
173 put_device(tty->dev);
174 kfree(tty->write_buf);
175 tty->magic = 0xDEADDEAD;
179 static inline struct tty_struct *file_tty(struct file *file)
181 return ((struct tty_file_private *)file->private_data)->tty;
184 int tty_alloc_file(struct file *file)
186 struct tty_file_private *priv;
188 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
192 file->private_data = priv;
197 /* Associate a new file with the tty structure */
198 void tty_add_file(struct tty_struct *tty, struct file *file)
200 struct tty_file_private *priv = file->private_data;
205 spin_lock(&tty_files_lock);
206 list_add(&priv->list, &tty->tty_files);
207 spin_unlock(&tty_files_lock);
211 * tty_free_file - free file->private_data
213 * This shall be used only for fail path handling when tty_add_file was not
216 void tty_free_file(struct file *file)
218 struct tty_file_private *priv = file->private_data;
220 file->private_data = NULL;
224 /* Delete file from its tty */
225 static void tty_del_file(struct file *file)
227 struct tty_file_private *priv = file->private_data;
229 spin_lock(&tty_files_lock);
230 list_del(&priv->list);
231 spin_unlock(&tty_files_lock);
236 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
239 * tty_name - return tty naming
240 * @tty: tty structure
241 * @buf: buffer for output
243 * Convert a tty structure into a name. The name reflects the kernel
244 * naming policy and if udev is in use may not reflect user space
249 char *tty_name(struct tty_struct *tty, char *buf)
251 if (!tty) /* Hmm. NULL pointer. That's fun. */
252 strcpy(buf, "NULL tty");
254 strcpy(buf, tty->name);
258 EXPORT_SYMBOL(tty_name);
260 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
263 #ifdef TTY_PARANOIA_CHECK
266 "null TTY for (%d:%d) in %s\n",
267 imajor(inode), iminor(inode), routine);
270 if (tty->magic != TTY_MAGIC) {
272 "bad magic number for tty struct (%d:%d) in %s\n",
273 imajor(inode), iminor(inode), routine);
280 static int check_tty_count(struct tty_struct *tty, const char *routine)
282 #ifdef CHECK_TTY_COUNT
286 spin_lock(&tty_files_lock);
287 list_for_each(p, &tty->tty_files) {
290 spin_unlock(&tty_files_lock);
291 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
292 tty->driver->subtype == PTY_TYPE_SLAVE &&
293 tty->link && tty->link->count)
295 if (tty->count != count) {
296 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
297 "!= #fd's(%d) in %s\n",
298 tty->name, tty->count, count, routine);
306 * get_tty_driver - find device of a tty
307 * @dev_t: device identifier
308 * @index: returns the index of the tty
310 * This routine returns a tty driver structure, given a device number
311 * and also passes back the index number.
313 * Locking: caller must hold tty_mutex
316 static struct tty_driver *get_tty_driver(dev_t device, int *index)
318 struct tty_driver *p;
320 list_for_each_entry(p, &tty_drivers, tty_drivers) {
321 dev_t base = MKDEV(p->major, p->minor_start);
322 if (device < base || device >= base + p->num)
324 *index = device - base;
325 return tty_driver_kref_get(p);
330 #ifdef CONFIG_CONSOLE_POLL
333 * tty_find_polling_driver - find device of a polled tty
334 * @name: name string to match
335 * @line: pointer to resulting tty line nr
337 * This routine returns a tty driver structure, given a name
338 * and the condition that the tty driver is capable of polled
341 struct tty_driver *tty_find_polling_driver(char *name, int *line)
343 struct tty_driver *p, *res = NULL;
348 for (str = name; *str; str++)
349 if ((*str >= '0' && *str <= '9') || *str == ',')
355 tty_line = simple_strtoul(str, &str, 10);
357 mutex_lock(&tty_mutex);
358 /* Search through the tty devices to look for a match */
359 list_for_each_entry(p, &tty_drivers, tty_drivers) {
360 if (strncmp(name, p->name, len) != 0)
368 if (tty_line >= 0 && tty_line < p->num && p->ops &&
369 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
370 res = tty_driver_kref_get(p);
375 mutex_unlock(&tty_mutex);
379 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
383 * tty_check_change - check for POSIX terminal changes
386 * If we try to write to, or set the state of, a terminal and we're
387 * not in the foreground, send a SIGTTOU. If the signal is blocked or
388 * ignored, go ahead and perform the operation. (POSIX 7.2)
393 int tty_check_change(struct tty_struct *tty)
398 if (current->signal->tty != tty)
401 spin_lock_irqsave(&tty->ctrl_lock, flags);
404 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
407 if (task_pgrp(current) == tty->pgrp)
409 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
410 if (is_ignored(SIGTTOU))
412 if (is_current_pgrp_orphaned()) {
416 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
417 set_thread_flag(TIF_SIGPENDING);
422 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
426 EXPORT_SYMBOL(tty_check_change);
428 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
429 size_t count, loff_t *ppos)
434 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
435 size_t count, loff_t *ppos)
440 /* No kernel lock held - none needed ;) */
441 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
443 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
446 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
449 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
452 static long hung_up_tty_compat_ioctl(struct file *file,
453 unsigned int cmd, unsigned long arg)
455 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
458 static const struct file_operations tty_fops = {
463 .unlocked_ioctl = tty_ioctl,
464 .compat_ioctl = tty_compat_ioctl,
466 .release = tty_release,
467 .fasync = tty_fasync,
470 static const struct file_operations console_fops = {
473 .write = redirected_tty_write,
475 .unlocked_ioctl = tty_ioctl,
476 .compat_ioctl = tty_compat_ioctl,
478 .release = tty_release,
479 .fasync = tty_fasync,
482 static const struct file_operations hung_up_tty_fops = {
484 .read = hung_up_tty_read,
485 .write = hung_up_tty_write,
486 .poll = hung_up_tty_poll,
487 .unlocked_ioctl = hung_up_tty_ioctl,
488 .compat_ioctl = hung_up_tty_compat_ioctl,
489 .release = tty_release,
492 static DEFINE_SPINLOCK(redirect_lock);
493 static struct file *redirect;
496 * tty_wakeup - request more data
499 * Internal and external helper for wakeups of tty. This function
500 * informs the line discipline if present that the driver is ready
501 * to receive more output data.
504 void tty_wakeup(struct tty_struct *tty)
506 struct tty_ldisc *ld;
508 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
509 ld = tty_ldisc_ref(tty);
511 if (ld->ops->write_wakeup)
512 ld->ops->write_wakeup(tty);
516 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
519 EXPORT_SYMBOL_GPL(tty_wakeup);
522 * tty_signal_session_leader - sends SIGHUP to session leader
523 * @tty controlling tty
524 * @exit_session if non-zero, signal all foreground group processes
526 * Send SIGHUP and SIGCONT to the session leader and its process group.
527 * Optionally, signal all processes in the foreground process group.
529 * Returns the number of processes in the session with this tty
530 * as their controlling terminal. This value is used to drop
531 * tty references for those processes.
533 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
535 struct task_struct *p;
537 struct pid *tty_pgrp = NULL;
539 read_lock(&tasklist_lock);
541 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
542 spin_lock_irq(&p->sighand->siglock);
543 if (p->signal->tty == tty) {
544 p->signal->tty = NULL;
545 /* We defer the dereferences outside fo
549 if (!p->signal->leader) {
550 spin_unlock_irq(&p->sighand->siglock);
553 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
554 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
555 put_pid(p->signal->tty_old_pgrp); /* A noop */
556 spin_lock(&tty->ctrl_lock);
557 tty_pgrp = get_pid(tty->pgrp);
559 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
560 spin_unlock(&tty->ctrl_lock);
561 spin_unlock_irq(&p->sighand->siglock);
562 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
564 read_unlock(&tasklist_lock);
568 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
576 * __tty_hangup - actual handler for hangup events
579 * This can be called by a "kworker" kernel thread. That is process
580 * synchronous but doesn't hold any locks, so we need to make sure we
581 * have the appropriate locks for what we're doing.
583 * The hangup event clears any pending redirections onto the hung up
584 * device. It ensures future writes will error and it does the needed
585 * line discipline hangup and signal delivery. The tty object itself
590 * redirect lock for undoing redirection
591 * file list lock for manipulating list of ttys
592 * tty_ldiscs_lock from called functions
593 * termios_rwsem resetting termios data
594 * tasklist_lock to walk task list for hangup event
595 * ->siglock to protect ->signal/->sighand
597 static void __tty_hangup(struct tty_struct *tty, int exit_session)
599 struct file *cons_filp = NULL;
600 struct file *filp, *f = NULL;
601 struct tty_file_private *priv;
602 int closecount = 0, n;
609 spin_lock(&redirect_lock);
610 if (redirect && file_tty(redirect) == tty) {
614 spin_unlock(&redirect_lock);
618 if (test_bit(TTY_HUPPED, &tty->flags)) {
623 /* some functions below drop BTM, so we need this bit */
624 set_bit(TTY_HUPPING, &tty->flags);
626 /* inuse_filps is protected by the single tty lock,
627 this really needs to change if we want to flush the
628 workqueue with the lock held */
629 check_tty_count(tty, "tty_hangup");
631 spin_lock(&tty_files_lock);
632 /* This breaks for file handles being sent over AF_UNIX sockets ? */
633 list_for_each_entry(priv, &tty->tty_files, list) {
635 if (filp->f_op->write == redirected_tty_write)
637 if (filp->f_op->write != tty_write)
640 __tty_fasync(-1, filp, 0); /* can't block */
641 filp->f_op = &hung_up_tty_fops;
643 spin_unlock(&tty_files_lock);
645 refs = tty_signal_session_leader(tty, exit_session);
646 /* Account for the p->signal references we killed */
651 * it drops BTM and thus races with reopen
652 * we protect the race by TTY_HUPPING
654 tty_ldisc_hangup(tty);
656 spin_lock_irq(&tty->ctrl_lock);
657 clear_bit(TTY_THROTTLED, &tty->flags);
658 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
659 put_pid(tty->session);
663 tty->ctrl_status = 0;
664 spin_unlock_irq(&tty->ctrl_lock);
667 * If one of the devices matches a console pointer, we
668 * cannot just call hangup() because that will cause
669 * tty->count and state->count to go out of sync.
670 * So we just call close() the right number of times.
674 for (n = 0; n < closecount; n++)
675 tty->ops->close(tty, cons_filp);
676 } else if (tty->ops->hangup)
677 tty->ops->hangup(tty);
679 * We don't want to have driver/ldisc interactions beyond
680 * the ones we did here. The driver layer expects no
681 * calls after ->hangup() from the ldisc side. However we
682 * can't yet guarantee all that.
684 set_bit(TTY_HUPPED, &tty->flags);
685 clear_bit(TTY_HUPPING, &tty->flags);
693 static void do_tty_hangup(struct work_struct *work)
695 struct tty_struct *tty =
696 container_of(work, struct tty_struct, hangup_work);
698 __tty_hangup(tty, 0);
702 * tty_hangup - trigger a hangup event
703 * @tty: tty to hangup
705 * A carrier loss (virtual or otherwise) has occurred on this like
706 * schedule a hangup sequence to run after this event.
709 void tty_hangup(struct tty_struct *tty)
711 #ifdef TTY_DEBUG_HANGUP
713 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
715 schedule_work(&tty->hangup_work);
718 EXPORT_SYMBOL(tty_hangup);
721 * tty_vhangup - process vhangup
722 * @tty: tty to hangup
724 * The user has asked via system call for the terminal to be hung up.
725 * We do this synchronously so that when the syscall returns the process
726 * is complete. That guarantee is necessary for security reasons.
729 void tty_vhangup(struct tty_struct *tty)
731 #ifdef TTY_DEBUG_HANGUP
734 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
736 __tty_hangup(tty, 0);
739 EXPORT_SYMBOL(tty_vhangup);
743 * tty_vhangup_self - process vhangup for own ctty
745 * Perform a vhangup on the current controlling tty
748 void tty_vhangup_self(void)
750 struct tty_struct *tty;
752 tty = get_current_tty();
760 * tty_vhangup_session - hangup session leader exit
761 * @tty: tty to hangup
763 * The session leader is exiting and hanging up its controlling terminal.
764 * Every process in the foreground process group is signalled SIGHUP.
766 * We do this synchronously so that when the syscall returns the process
767 * is complete. That guarantee is necessary for security reasons.
770 static void tty_vhangup_session(struct tty_struct *tty)
772 #ifdef TTY_DEBUG_HANGUP
775 printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty, buf));
777 __tty_hangup(tty, 1);
781 * tty_hung_up_p - was tty hung up
782 * @filp: file pointer of tty
784 * Return true if the tty has been subject to a vhangup or a carrier
788 int tty_hung_up_p(struct file *filp)
790 return (filp->f_op == &hung_up_tty_fops);
793 EXPORT_SYMBOL(tty_hung_up_p);
795 static void session_clear_tty(struct pid *session)
797 struct task_struct *p;
798 do_each_pid_task(session, PIDTYPE_SID, p) {
800 } while_each_pid_task(session, PIDTYPE_SID, p);
804 * disassociate_ctty - disconnect controlling tty
805 * @on_exit: true if exiting so need to "hang up" the session
807 * This function is typically called only by the session leader, when
808 * it wants to disassociate itself from its controlling tty.
810 * It performs the following functions:
811 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
812 * (2) Clears the tty from being controlling the session
813 * (3) Clears the controlling tty for all processes in the
816 * The argument on_exit is set to 1 if called when a process is
817 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
820 * BTM is taken for hysterical raisins, and held when
821 * called from no_tty().
822 * tty_mutex is taken to protect tty
823 * ->siglock is taken to protect ->signal/->sighand
824 * tasklist_lock is taken to walk process list for sessions
825 * ->siglock is taken to protect ->signal/->sighand
828 void disassociate_ctty(int on_exit)
830 struct tty_struct *tty;
832 if (!current->signal->leader)
835 tty = get_current_tty();
837 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
838 tty_vhangup_session(tty);
840 struct pid *tty_pgrp = tty_get_pgrp(tty);
842 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
844 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
850 } else if (on_exit) {
851 struct pid *old_pgrp;
852 spin_lock_irq(¤t->sighand->siglock);
853 old_pgrp = current->signal->tty_old_pgrp;
854 current->signal->tty_old_pgrp = NULL;
855 spin_unlock_irq(¤t->sighand->siglock);
857 kill_pgrp(old_pgrp, SIGHUP, on_exit);
858 kill_pgrp(old_pgrp, SIGCONT, on_exit);
864 spin_lock_irq(¤t->sighand->siglock);
865 put_pid(current->signal->tty_old_pgrp);
866 current->signal->tty_old_pgrp = NULL;
868 tty = tty_kref_get(current->signal->tty);
871 spin_lock_irqsave(&tty->ctrl_lock, flags);
872 put_pid(tty->session);
876 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
879 #ifdef TTY_DEBUG_HANGUP
880 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
885 spin_unlock_irq(¤t->sighand->siglock);
886 /* Now clear signal->tty under the lock */
887 read_lock(&tasklist_lock);
888 session_clear_tty(task_session(current));
889 read_unlock(&tasklist_lock);
894 * no_tty - Ensure the current process does not have a controlling tty
898 /* FIXME: Review locking here. The tty_lock never covered any race
899 between a new association and proc_clear_tty but possible we need
900 to protect against this anyway */
901 struct task_struct *tsk = current;
902 disassociate_ctty(0);
908 * stop_tty - propagate flow control
911 * Perform flow control to the driver. May be called
912 * on an already stopped device and will not re-call the driver
915 * This functionality is used by both the line disciplines for
916 * halting incoming flow and by the driver. It may therefore be
917 * called from any context, may be under the tty atomic_write_lock
924 void __stop_tty(struct tty_struct *tty)
930 (tty->ops->stop)(tty);
933 void stop_tty(struct tty_struct *tty)
937 spin_lock_irqsave(&tty->flow_lock, flags);
939 spin_unlock_irqrestore(&tty->flow_lock, flags);
941 EXPORT_SYMBOL(stop_tty);
944 * start_tty - propagate flow control
947 * Start a tty that has been stopped if at all possible. If this
948 * tty was previous stopped and is now being started, the driver
949 * start method is invoked and the line discipline woken.
955 void __start_tty(struct tty_struct *tty)
957 if (!tty->stopped || tty->flow_stopped)
961 (tty->ops->start)(tty);
965 void start_tty(struct tty_struct *tty)
969 spin_lock_irqsave(&tty->flow_lock, flags);
971 spin_unlock_irqrestore(&tty->flow_lock, flags);
973 EXPORT_SYMBOL(start_tty);
975 /* We limit tty time update visibility to every 8 seconds or so. */
976 static void tty_update_time(struct timespec *time)
978 unsigned long sec = get_seconds() & ~7;
979 if ((long)(sec - time->tv_sec) > 0)
984 * tty_read - read method for tty device files
985 * @file: pointer to tty file
987 * @count: size of user buffer
990 * Perform the read system call function on this terminal device. Checks
991 * for hung up devices before calling the line discipline method.
994 * Locks the line discipline internally while needed. Multiple
995 * read calls may be outstanding in parallel.
998 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1002 struct inode *inode = file_inode(file);
1003 struct tty_struct *tty = file_tty(file);
1004 struct tty_ldisc *ld;
1006 if (tty_paranoia_check(tty, inode, "tty_read"))
1008 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1011 /* We want to wait for the line discipline to sort out in this
1013 ld = tty_ldisc_ref_wait(tty);
1015 i = (ld->ops->read)(tty, file, buf, count);
1018 tty_ldisc_deref(ld);
1021 tty_update_time(&inode->i_atime);
1026 void tty_write_unlock(struct tty_struct *tty)
1027 __releases(&tty->atomic_write_lock)
1029 mutex_unlock(&tty->atomic_write_lock);
1030 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1033 int tty_write_lock(struct tty_struct *tty, int ndelay)
1034 __acquires(&tty->atomic_write_lock)
1036 if (!mutex_trylock(&tty->atomic_write_lock)) {
1039 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1040 return -ERESTARTSYS;
1046 * Split writes up in sane blocksizes to avoid
1047 * denial-of-service type attacks
1049 static inline ssize_t do_tty_write(
1050 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1051 struct tty_struct *tty,
1053 const char __user *buf,
1056 ssize_t ret, written = 0;
1059 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1064 * We chunk up writes into a temporary buffer. This
1065 * simplifies low-level drivers immensely, since they
1066 * don't have locking issues and user mode accesses.
1068 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1071 * The default chunk-size is 2kB, because the NTTY
1072 * layer has problems with bigger chunks. It will
1073 * claim to be able to handle more characters than
1076 * FIXME: This can probably go away now except that 64K chunks
1077 * are too likely to fail unless switched to vmalloc...
1080 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1085 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1086 if (tty->write_cnt < chunk) {
1087 unsigned char *buf_chunk;
1092 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1097 kfree(tty->write_buf);
1098 tty->write_cnt = chunk;
1099 tty->write_buf = buf_chunk;
1102 /* Do the write .. */
1104 size_t size = count;
1108 if (copy_from_user(tty->write_buf, buf, size))
1110 ret = write(tty, file, tty->write_buf, size);
1119 if (signal_pending(current))
1124 tty_update_time(&file_inode(file)->i_mtime);
1128 tty_write_unlock(tty);
1133 * tty_write_message - write a message to a certain tty, not just the console.
1134 * @tty: the destination tty_struct
1135 * @msg: the message to write
1137 * This is used for messages that need to be redirected to a specific tty.
1138 * We don't put it into the syslog queue right now maybe in the future if
1141 * We must still hold the BTM and test the CLOSING flag for the moment.
1144 void tty_write_message(struct tty_struct *tty, char *msg)
1147 mutex_lock(&tty->atomic_write_lock);
1149 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1151 tty->ops->write(tty, msg, strlen(msg));
1154 tty_write_unlock(tty);
1161 * tty_write - write method for tty device file
1162 * @file: tty file pointer
1163 * @buf: user data to write
1164 * @count: bytes to write
1167 * Write data to a tty device via the line discipline.
1170 * Locks the line discipline as required
1171 * Writes to the tty driver are serialized by the atomic_write_lock
1172 * and are then processed in chunks to the device. The line discipline
1173 * write method will not be invoked in parallel for each device.
1176 static ssize_t tty_write(struct file *file, const char __user *buf,
1177 size_t count, loff_t *ppos)
1179 struct tty_struct *tty = file_tty(file);
1180 struct tty_ldisc *ld;
1183 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1185 if (!tty || !tty->ops->write ||
1186 (test_bit(TTY_IO_ERROR, &tty->flags)))
1188 /* Short term debug to catch buggy drivers */
1189 if (tty->ops->write_room == NULL)
1190 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1192 ld = tty_ldisc_ref_wait(tty);
1193 if (!ld->ops->write)
1196 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1197 tty_ldisc_deref(ld);
1201 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1202 size_t count, loff_t *ppos)
1204 struct file *p = NULL;
1206 spin_lock(&redirect_lock);
1208 p = get_file(redirect);
1209 spin_unlock(&redirect_lock);
1213 res = vfs_write(p, buf, count, &p->f_pos);
1217 return tty_write(file, buf, count, ppos);
1220 static char ptychar[] = "pqrstuvwxyzabcde";
1223 * pty_line_name - generate name for a pty
1224 * @driver: the tty driver in use
1225 * @index: the minor number
1226 * @p: output buffer of at least 6 bytes
1228 * Generate a name from a driver reference and write it to the output
1233 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1235 int i = index + driver->name_base;
1236 /* ->name is initialized to "ttyp", but "tty" is expected */
1237 sprintf(p, "%s%c%x",
1238 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1239 ptychar[i >> 4 & 0xf], i & 0xf);
1243 * tty_line_name - generate name for a tty
1244 * @driver: the tty driver in use
1245 * @index: the minor number
1246 * @p: output buffer of at least 7 bytes
1248 * Generate a name from a driver reference and write it to the output
1253 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1255 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1256 return sprintf(p, "%s", driver->name);
1258 return sprintf(p, "%s%d", driver->name,
1259 index + driver->name_base);
1263 * tty_driver_lookup_tty() - find an existing tty, if any
1264 * @driver: the driver for the tty
1265 * @idx: the minor number
1267 * Return the tty, if found or ERR_PTR() otherwise.
1269 * Locking: tty_mutex must be held. If tty is found, the mutex must
1270 * be held until the 'fast-open' is also done. Will change once we
1271 * have refcounting in the driver and per driver locking
1273 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1274 struct inode *inode, int idx)
1276 if (driver->ops->lookup)
1277 return driver->ops->lookup(driver, inode, idx);
1279 return driver->ttys[idx];
1283 * tty_init_termios - helper for termios setup
1284 * @tty: the tty to set up
1286 * Initialise the termios structures for this tty. Thus runs under
1287 * the tty_mutex currently so we can be relaxed about ordering.
1290 int tty_init_termios(struct tty_struct *tty)
1292 struct ktermios *tp;
1293 int idx = tty->index;
1295 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1296 tty->termios = tty->driver->init_termios;
1298 /* Check for lazy saved data */
1299 tp = tty->driver->termios[idx];
1303 tty->termios = tty->driver->init_termios;
1305 /* Compatibility until drivers always set this */
1306 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1307 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1310 EXPORT_SYMBOL_GPL(tty_init_termios);
1312 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1314 int ret = tty_init_termios(tty);
1318 tty_driver_kref_get(driver);
1320 driver->ttys[tty->index] = tty;
1323 EXPORT_SYMBOL_GPL(tty_standard_install);
1326 * tty_driver_install_tty() - install a tty entry in the driver
1327 * @driver: the driver for the tty
1330 * Install a tty object into the driver tables. The tty->index field
1331 * will be set by the time this is called. This method is responsible
1332 * for ensuring any need additional structures are allocated and
1335 * Locking: tty_mutex for now
1337 static int tty_driver_install_tty(struct tty_driver *driver,
1338 struct tty_struct *tty)
1340 return driver->ops->install ? driver->ops->install(driver, tty) :
1341 tty_standard_install(driver, tty);
1345 * tty_driver_remove_tty() - remove a tty from the driver tables
1346 * @driver: the driver for the tty
1347 * @idx: the minor number
1349 * Remvoe a tty object from the driver tables. The tty->index field
1350 * will be set by the time this is called.
1352 * Locking: tty_mutex for now
1354 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1356 if (driver->ops->remove)
1357 driver->ops->remove(driver, tty);
1359 driver->ttys[tty->index] = NULL;
1363 * tty_reopen() - fast re-open of an open tty
1364 * @tty - the tty to open
1366 * Return 0 on success, -errno on error.
1368 * Locking: tty_mutex must be held from the time the tty was found
1369 * till this open completes.
1371 static int tty_reopen(struct tty_struct *tty)
1373 struct tty_driver *driver = tty->driver;
1375 if (test_bit(TTY_CLOSING, &tty->flags) ||
1376 test_bit(TTY_HUPPING, &tty->flags))
1379 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1380 driver->subtype == PTY_TYPE_MASTER) {
1382 * special case for PTY masters: only one open permitted,
1383 * and the slave side open count is incremented as well.
1392 WARN_ON(!tty->ldisc);
1398 * tty_init_dev - initialise a tty device
1399 * @driver: tty driver we are opening a device on
1400 * @idx: device index
1401 * @ret_tty: returned tty structure
1403 * Prepare a tty device. This may not be a "new" clean device but
1404 * could also be an active device. The pty drivers require special
1405 * handling because of this.
1408 * The function is called under the tty_mutex, which
1409 * protects us from the tty struct or driver itself going away.
1411 * On exit the tty device has the line discipline attached and
1412 * a reference count of 1. If a pair was created for pty/tty use
1413 * and the other was a pty master then it too has a reference count of 1.
1415 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1416 * failed open. The new code protects the open with a mutex, so it's
1417 * really quite straightforward. The mutex locking can probably be
1418 * relaxed for the (most common) case of reopening a tty.
1421 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1423 struct tty_struct *tty;
1427 * First time open is complex, especially for PTY devices.
1428 * This code guarantees that either everything succeeds and the
1429 * TTY is ready for operation, or else the table slots are vacated
1430 * and the allocated memory released. (Except that the termios
1431 * and locked termios may be retained.)
1434 if (!try_module_get(driver->owner))
1435 return ERR_PTR(-ENODEV);
1437 tty = alloc_tty_struct(driver, idx);
1440 goto err_module_put;
1444 retval = tty_driver_install_tty(driver, tty);
1446 goto err_deinit_tty;
1449 tty->port = driver->ports[idx];
1451 WARN_RATELIMIT(!tty->port,
1452 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1453 __func__, tty->driver->name);
1455 tty->port->itty = tty;
1458 * Structures all installed ... call the ldisc open routines.
1459 * If we fail here just call release_tty to clean up. No need
1460 * to decrement the use counts, as release_tty doesn't care.
1462 retval = tty_ldisc_setup(tty, tty->link);
1464 goto err_release_tty;
1465 /* Return the tty locked so that it cannot vanish under the caller */
1470 deinitialize_tty_struct(tty);
1471 free_tty_struct(tty);
1473 module_put(driver->owner);
1474 return ERR_PTR(retval);
1476 /* call the tty release_tty routine to clean out this slot */
1479 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1480 "clearing slot %d\n", idx);
1481 release_tty(tty, idx);
1482 return ERR_PTR(retval);
1485 void tty_free_termios(struct tty_struct *tty)
1487 struct ktermios *tp;
1488 int idx = tty->index;
1490 /* If the port is going to reset then it has no termios to save */
1491 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1494 /* Stash the termios data */
1495 tp = tty->driver->termios[idx];
1497 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1499 pr_warn("tty: no memory to save termios state.\n");
1502 tty->driver->termios[idx] = tp;
1506 EXPORT_SYMBOL(tty_free_termios);
1509 * tty_flush_works - flush all works of a tty
1510 * @tty: tty device to flush works for
1512 * Sync flush all works belonging to @tty.
1514 static void tty_flush_works(struct tty_struct *tty)
1516 flush_work(&tty->SAK_work);
1517 flush_work(&tty->hangup_work);
1521 * release_one_tty - release tty structure memory
1522 * @kref: kref of tty we are obliterating
1524 * Releases memory associated with a tty structure, and clears out the
1525 * driver table slots. This function is called when a device is no longer
1526 * in use. It also gets called when setup of a device fails.
1529 * takes the file list lock internally when working on the list
1530 * of ttys that the driver keeps.
1532 * This method gets called from a work queue so that the driver private
1533 * cleanup ops can sleep (needed for USB at least)
1535 static void release_one_tty(struct work_struct *work)
1537 struct tty_struct *tty =
1538 container_of(work, struct tty_struct, hangup_work);
1539 struct tty_driver *driver = tty->driver;
1540 struct module *owner = driver->owner;
1542 if (tty->ops->cleanup)
1543 tty->ops->cleanup(tty);
1546 tty_driver_kref_put(driver);
1549 spin_lock(&tty_files_lock);
1550 list_del_init(&tty->tty_files);
1551 spin_unlock(&tty_files_lock);
1554 put_pid(tty->session);
1555 free_tty_struct(tty);
1558 static void queue_release_one_tty(struct kref *kref)
1560 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1562 /* The hangup queue is now free so we can reuse it rather than
1563 waste a chunk of memory for each port */
1564 INIT_WORK(&tty->hangup_work, release_one_tty);
1565 schedule_work(&tty->hangup_work);
1569 * tty_kref_put - release a tty kref
1572 * Release a reference to a tty device and if need be let the kref
1573 * layer destruct the object for us
1576 void tty_kref_put(struct tty_struct *tty)
1579 kref_put(&tty->kref, queue_release_one_tty);
1581 EXPORT_SYMBOL(tty_kref_put);
1584 * release_tty - release tty structure memory
1586 * Release both @tty and a possible linked partner (think pty pair),
1587 * and decrement the refcount of the backing module.
1591 * takes the file list lock internally when working on the list
1592 * of ttys that the driver keeps.
1595 static void release_tty(struct tty_struct *tty, int idx)
1597 /* This should always be true but check for the moment */
1598 WARN_ON(tty->index != idx);
1599 WARN_ON(!mutex_is_locked(&tty_mutex));
1600 if (tty->ops->shutdown)
1601 tty->ops->shutdown(tty);
1602 tty_free_termios(tty);
1603 tty_driver_remove_tty(tty->driver, tty);
1604 tty->port->itty = NULL;
1606 tty->link->port->itty = NULL;
1607 cancel_work_sync(&tty->port->buf.work);
1610 tty_kref_put(tty->link);
1615 * tty_release_checks - check a tty before real release
1616 * @tty: tty to check
1617 * @o_tty: link of @tty (if any)
1618 * @idx: index of the tty
1620 * Performs some paranoid checking before true release of the @tty.
1621 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1623 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1626 #ifdef TTY_PARANOIA_CHECK
1627 if (idx < 0 || idx >= tty->driver->num) {
1628 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1629 __func__, tty->name);
1633 /* not much to check for devpts */
1634 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1637 if (tty != tty->driver->ttys[idx]) {
1638 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1639 __func__, idx, tty->name);
1642 if (tty->driver->other) {
1643 if (o_tty != tty->driver->other->ttys[idx]) {
1644 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1645 __func__, idx, tty->name);
1648 if (o_tty->link != tty) {
1649 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1658 * tty_release - vfs callback for close
1659 * @inode: inode of tty
1660 * @filp: file pointer for handle to tty
1662 * Called the last time each file handle is closed that references
1663 * this tty. There may however be several such references.
1666 * Takes bkl. See tty_release_dev
1668 * Even releasing the tty structures is a tricky business.. We have
1669 * to be very careful that the structures are all released at the
1670 * same time, as interrupts might otherwise get the wrong pointers.
1672 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1673 * lead to double frees or releasing memory still in use.
1676 int tty_release(struct inode *inode, struct file *filp)
1678 struct tty_struct *tty = file_tty(filp);
1679 struct tty_struct *o_tty;
1680 int pty_master, tty_closing, o_tty_closing, do_sleep;
1684 if (tty_paranoia_check(tty, inode, __func__))
1688 check_tty_count(tty, __func__);
1690 __tty_fasync(-1, filp, 0);
1693 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1694 tty->driver->subtype == PTY_TYPE_MASTER);
1695 /* Review: parallel close */
1698 if (tty_release_checks(tty, o_tty, idx)) {
1703 #ifdef TTY_DEBUG_HANGUP
1704 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1705 tty_name(tty, buf), tty->count);
1708 if (tty->ops->close)
1709 tty->ops->close(tty, filp);
1713 * Sanity check: if tty->count is going to zero, there shouldn't be
1714 * any waiters on tty->read_wait or tty->write_wait. We test the
1715 * wait queues and kick everyone out _before_ actually starting to
1716 * close. This ensures that we won't block while releasing the tty
1719 * The test for the o_tty closing is necessary, since the master and
1720 * slave sides may close in any order. If the slave side closes out
1721 * first, its count will be one, since the master side holds an open.
1722 * Thus this test wouldn't be triggered at the time the slave closes,
1725 * Note that it's possible for the tty to be opened again while we're
1726 * flushing out waiters. By recalculating the closing flags before
1727 * each iteration we avoid any problems.
1730 /* Guard against races with tty->count changes elsewhere and
1731 opens on /dev/tty */
1733 mutex_lock(&tty_mutex);
1734 tty_lock_pair(tty, o_tty);
1735 tty_closing = tty->count <= 1;
1736 o_tty_closing = o_tty &&
1737 (o_tty->count <= (pty_master ? 1 : 0));
1741 if (waitqueue_active(&tty->read_wait)) {
1742 wake_up_poll(&tty->read_wait, POLLIN);
1745 if (waitqueue_active(&tty->write_wait)) {
1746 wake_up_poll(&tty->write_wait, POLLOUT);
1750 if (o_tty_closing) {
1751 if (waitqueue_active(&o_tty->read_wait)) {
1752 wake_up_poll(&o_tty->read_wait, POLLIN);
1755 if (waitqueue_active(&o_tty->write_wait)) {
1756 wake_up_poll(&o_tty->write_wait, POLLOUT);
1763 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1764 __func__, tty_name(tty, buf));
1765 tty_unlock_pair(tty, o_tty);
1766 mutex_unlock(&tty_mutex);
1771 * The closing flags are now consistent with the open counts on
1772 * both sides, and we've completed the last operation that could
1773 * block, so it's safe to proceed with closing.
1775 * We must *not* drop the tty_mutex until we ensure that a further
1776 * entry into tty_open can not pick up this tty.
1779 if (--o_tty->count < 0) {
1780 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1781 __func__, o_tty->count, tty_name(o_tty, buf));
1785 if (--tty->count < 0) {
1786 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1787 __func__, tty->count, tty_name(tty, buf));
1792 * We've decremented tty->count, so we need to remove this file
1793 * descriptor off the tty->tty_files list; this serves two
1795 * - check_tty_count sees the correct number of file descriptors
1796 * associated with this tty.
1797 * - do_tty_hangup no longer sees this file descriptor as
1798 * something that needs to be handled for hangups.
1803 * Perform some housekeeping before deciding whether to return.
1805 * Set the TTY_CLOSING flag if this was the last open. In the
1806 * case of a pty we may have to wait around for the other side
1807 * to close, and TTY_CLOSING makes sure we can't be reopened.
1810 set_bit(TTY_CLOSING, &tty->flags);
1812 set_bit(TTY_CLOSING, &o_tty->flags);
1815 * If _either_ side is closing, make sure there aren't any
1816 * processes that still think tty or o_tty is their controlling
1819 if (tty_closing || o_tty_closing) {
1820 read_lock(&tasklist_lock);
1821 session_clear_tty(tty->session);
1823 session_clear_tty(o_tty->session);
1824 read_unlock(&tasklist_lock);
1827 mutex_unlock(&tty_mutex);
1828 tty_unlock_pair(tty, o_tty);
1829 /* At this point the TTY_CLOSING flag should ensure a dead tty
1830 cannot be re-opened by a racing opener */
1832 /* check whether both sides are closing ... */
1833 if (!tty_closing || (o_tty && !o_tty_closing))
1836 #ifdef TTY_DEBUG_HANGUP
1837 printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
1840 * Ask the line discipline code to release its structures
1842 tty_ldisc_release(tty, o_tty);
1844 /* Wait for pending work before tty destruction commmences */
1845 tty_flush_works(tty);
1847 tty_flush_works(o_tty);
1849 #ifdef TTY_DEBUG_HANGUP
1850 printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
1853 * The release_tty function takes care of the details of clearing
1854 * the slots and preserving the termios structure. The tty_unlock_pair
1855 * should be safe as we keep a kref while the tty is locked (so the
1856 * unlock never unlocks a freed tty).
1858 mutex_lock(&tty_mutex);
1859 release_tty(tty, idx);
1860 mutex_unlock(&tty_mutex);
1866 * tty_open_current_tty - get tty of current task for open
1867 * @device: device number
1868 * @filp: file pointer to tty
1869 * @return: tty of the current task iff @device is /dev/tty
1871 * We cannot return driver and index like for the other nodes because
1872 * devpts will not work then. It expects inodes to be from devpts FS.
1874 * We need to move to returning a refcounted object from all the lookup
1875 * paths including this one.
1877 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1879 struct tty_struct *tty;
1881 if (device != MKDEV(TTYAUX_MAJOR, 0))
1884 tty = get_current_tty();
1886 return ERR_PTR(-ENXIO);
1888 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1891 /* FIXME: we put a reference and return a TTY! */
1892 /* This is only safe because the caller holds tty_mutex */
1897 * tty_lookup_driver - lookup a tty driver for a given device file
1898 * @device: device number
1899 * @filp: file pointer to tty
1900 * @noctty: set if the device should not become a controlling tty
1901 * @index: index for the device in the @return driver
1902 * @return: driver for this inode (with increased refcount)
1904 * If @return is not erroneous, the caller is responsible to decrement the
1905 * refcount by tty_driver_kref_put.
1907 * Locking: tty_mutex protects get_tty_driver
1909 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1910 int *noctty, int *index)
1912 struct tty_driver *driver;
1916 case MKDEV(TTY_MAJOR, 0): {
1917 extern struct tty_driver *console_driver;
1918 driver = tty_driver_kref_get(console_driver);
1919 *index = fg_console;
1924 case MKDEV(TTYAUX_MAJOR, 1): {
1925 struct tty_driver *console_driver = console_device(index);
1926 if (console_driver) {
1927 driver = tty_driver_kref_get(console_driver);
1929 /* Don't let /dev/console block */
1930 filp->f_flags |= O_NONBLOCK;
1935 return ERR_PTR(-ENODEV);
1938 driver = get_tty_driver(device, index);
1940 return ERR_PTR(-ENODEV);
1947 * tty_open - open a tty device
1948 * @inode: inode of device file
1949 * @filp: file pointer to tty
1951 * tty_open and tty_release keep up the tty count that contains the
1952 * number of opens done on a tty. We cannot use the inode-count, as
1953 * different inodes might point to the same tty.
1955 * Open-counting is needed for pty masters, as well as for keeping
1956 * track of serial lines: DTR is dropped when the last close happens.
1957 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1959 * The termios state of a pty is reset on first open so that
1960 * settings don't persist across reuse.
1962 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1963 * tty->count should protect the rest.
1964 * ->siglock protects ->signal/->sighand
1966 * Note: the tty_unlock/lock cases without a ref are only safe due to
1970 static int tty_open(struct inode *inode, struct file *filp)
1972 struct tty_struct *tty;
1974 struct tty_driver *driver = NULL;
1976 dev_t device = inode->i_rdev;
1977 unsigned saved_flags = filp->f_flags;
1979 nonseekable_open(inode, filp);
1982 retval = tty_alloc_file(filp);
1986 noctty = filp->f_flags & O_NOCTTY;
1990 mutex_lock(&tty_mutex);
1991 /* This is protected by the tty_mutex */
1992 tty = tty_open_current_tty(device, filp);
1994 retval = PTR_ERR(tty);
1997 driver = tty_lookup_driver(device, filp, &noctty, &index);
1998 if (IS_ERR(driver)) {
1999 retval = PTR_ERR(driver);
2003 /* check whether we're reopening an existing tty */
2004 tty = tty_driver_lookup_tty(driver, inode, index);
2006 retval = PTR_ERR(tty);
2013 retval = tty_reopen(tty);
2016 tty = ERR_PTR(retval);
2018 } else /* Returns with the tty_lock held for now */
2019 tty = tty_init_dev(driver, index);
2021 mutex_unlock(&tty_mutex);
2023 tty_driver_kref_put(driver);
2025 retval = PTR_ERR(tty);
2029 tty_add_file(tty, filp);
2031 check_tty_count(tty, __func__);
2032 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2033 tty->driver->subtype == PTY_TYPE_MASTER)
2035 #ifdef TTY_DEBUG_HANGUP
2036 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
2039 retval = tty->ops->open(tty, filp);
2042 filp->f_flags = saved_flags;
2044 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
2045 !capable(CAP_SYS_ADMIN))
2049 #ifdef TTY_DEBUG_HANGUP
2050 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
2053 tty_unlock(tty); /* need to call tty_release without BTM */
2054 tty_release(inode, filp);
2055 if (retval != -ERESTARTSYS)
2058 if (signal_pending(current))
2063 * Need to reset f_op in case a hangup happened.
2065 if (filp->f_op == &hung_up_tty_fops)
2066 filp->f_op = &tty_fops;
2069 clear_bit(TTY_HUPPED, &tty->flags);
2073 mutex_lock(&tty_mutex);
2075 spin_lock_irq(¤t->sighand->siglock);
2077 current->signal->leader &&
2078 !current->signal->tty &&
2079 tty->session == NULL)
2080 __proc_set_tty(current, tty);
2081 spin_unlock_irq(¤t->sighand->siglock);
2083 mutex_unlock(&tty_mutex);
2086 mutex_unlock(&tty_mutex);
2087 /* after locks to avoid deadlock */
2088 if (!IS_ERR_OR_NULL(driver))
2089 tty_driver_kref_put(driver);
2091 tty_free_file(filp);
2098 * tty_poll - check tty status
2099 * @filp: file being polled
2100 * @wait: poll wait structures to update
2102 * Call the line discipline polling method to obtain the poll
2103 * status of the device.
2105 * Locking: locks called line discipline but ldisc poll method
2106 * may be re-entered freely by other callers.
2109 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2111 struct tty_struct *tty = file_tty(filp);
2112 struct tty_ldisc *ld;
2115 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2118 ld = tty_ldisc_ref_wait(tty);
2120 ret = (ld->ops->poll)(tty, filp, wait);
2121 tty_ldisc_deref(ld);
2125 static int __tty_fasync(int fd, struct file *filp, int on)
2127 struct tty_struct *tty = file_tty(filp);
2128 struct tty_ldisc *ldisc;
2129 unsigned long flags;
2132 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2135 retval = fasync_helper(fd, filp, on, &tty->fasync);
2139 ldisc = tty_ldisc_ref(tty);
2141 if (ldisc->ops->fasync)
2142 ldisc->ops->fasync(tty, on);
2143 tty_ldisc_deref(ldisc);
2150 spin_lock_irqsave(&tty->ctrl_lock, flags);
2153 type = PIDTYPE_PGID;
2155 pid = task_pid(current);
2159 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2160 retval = __f_setown(filp, pid, type, 0);
2167 static int tty_fasync(int fd, struct file *filp, int on)
2169 struct tty_struct *tty = file_tty(filp);
2173 retval = __tty_fasync(fd, filp, on);
2180 * tiocsti - fake input character
2181 * @tty: tty to fake input into
2182 * @p: pointer to character
2184 * Fake input to a tty device. Does the necessary locking and
2187 * FIXME: does not honour flow control ??
2190 * Called functions take tty_ldiscs_lock
2191 * current->signal->tty check is safe without locks
2193 * FIXME: may race normal receive processing
2196 static int tiocsti(struct tty_struct *tty, char __user *p)
2199 struct tty_ldisc *ld;
2201 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2203 if (get_user(ch, p))
2205 tty_audit_tiocsti(tty, ch);
2206 ld = tty_ldisc_ref_wait(tty);
2207 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2208 tty_ldisc_deref(ld);
2213 * tiocgwinsz - implement window query ioctl
2215 * @arg: user buffer for result
2217 * Copies the kernel idea of the window size into the user buffer.
2219 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2223 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2227 mutex_lock(&tty->winsize_mutex);
2228 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2229 mutex_unlock(&tty->winsize_mutex);
2231 return err ? -EFAULT: 0;
2235 * tty_do_resize - resize event
2236 * @tty: tty being resized
2237 * @rows: rows (character)
2238 * @cols: cols (character)
2240 * Update the termios variables and send the necessary signals to
2241 * peform a terminal resize correctly
2244 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2247 unsigned long flags;
2250 mutex_lock(&tty->winsize_mutex);
2251 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2253 /* Get the PID values and reference them so we can
2254 avoid holding the tty ctrl lock while sending signals */
2255 spin_lock_irqsave(&tty->ctrl_lock, flags);
2256 pgrp = get_pid(tty->pgrp);
2257 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2260 kill_pgrp(pgrp, SIGWINCH, 1);
2265 mutex_unlock(&tty->winsize_mutex);
2268 EXPORT_SYMBOL(tty_do_resize);
2271 * tiocswinsz - implement window size set ioctl
2272 * @tty; tty side of tty
2273 * @arg: user buffer for result
2275 * Copies the user idea of the window size to the kernel. Traditionally
2276 * this is just advisory information but for the Linux console it
2277 * actually has driver level meaning and triggers a VC resize.
2280 * Driver dependent. The default do_resize method takes the
2281 * tty termios mutex and ctrl_lock. The console takes its own lock
2282 * then calls into the default method.
2285 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2287 struct winsize tmp_ws;
2288 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2291 if (tty->ops->resize)
2292 return tty->ops->resize(tty, &tmp_ws);
2294 return tty_do_resize(tty, &tmp_ws);
2298 * tioccons - allow admin to move logical console
2299 * @file: the file to become console
2301 * Allow the administrator to move the redirected console device
2303 * Locking: uses redirect_lock to guard the redirect information
2306 static int tioccons(struct file *file)
2308 if (!capable(CAP_SYS_ADMIN))
2310 if (file->f_op->write == redirected_tty_write) {
2312 spin_lock(&redirect_lock);
2315 spin_unlock(&redirect_lock);
2320 spin_lock(&redirect_lock);
2322 spin_unlock(&redirect_lock);
2325 redirect = get_file(file);
2326 spin_unlock(&redirect_lock);
2331 * fionbio - non blocking ioctl
2332 * @file: file to set blocking value
2333 * @p: user parameter
2335 * Historical tty interfaces had a blocking control ioctl before
2336 * the generic functionality existed. This piece of history is preserved
2337 * in the expected tty API of posix OS's.
2339 * Locking: none, the open file handle ensures it won't go away.
2342 static int fionbio(struct file *file, int __user *p)
2346 if (get_user(nonblock, p))
2349 spin_lock(&file->f_lock);
2351 file->f_flags |= O_NONBLOCK;
2353 file->f_flags &= ~O_NONBLOCK;
2354 spin_unlock(&file->f_lock);
2359 * tiocsctty - set controlling tty
2360 * @tty: tty structure
2361 * @arg: user argument
2363 * This ioctl is used to manage job control. It permits a session
2364 * leader to set this tty as the controlling tty for the session.
2367 * Takes tty_mutex() to protect tty instance
2368 * Takes tasklist_lock internally to walk sessions
2369 * Takes ->siglock() when updating signal->tty
2372 static int tiocsctty(struct tty_struct *tty, int arg)
2375 if (current->signal->leader && (task_session(current) == tty->session))
2378 mutex_lock(&tty_mutex);
2380 * The process must be a session leader and
2381 * not have a controlling tty already.
2383 if (!current->signal->leader || current->signal->tty) {
2390 * This tty is already the controlling
2391 * tty for another session group!
2393 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2397 read_lock(&tasklist_lock);
2398 session_clear_tty(tty->session);
2399 read_unlock(&tasklist_lock);
2405 proc_set_tty(current, tty);
2407 mutex_unlock(&tty_mutex);
2412 * tty_get_pgrp - return a ref counted pgrp pid
2415 * Returns a refcounted instance of the pid struct for the process
2416 * group controlling the tty.
2419 struct pid *tty_get_pgrp(struct tty_struct *tty)
2421 unsigned long flags;
2424 spin_lock_irqsave(&tty->ctrl_lock, flags);
2425 pgrp = get_pid(tty->pgrp);
2426 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2430 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2433 * tiocgpgrp - get process group
2434 * @tty: tty passed by user
2435 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2438 * Obtain the process group of the tty. If there is no process group
2441 * Locking: none. Reference to current->signal->tty is safe.
2444 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2449 * (tty == real_tty) is a cheap way of
2450 * testing if the tty is NOT a master pty.
2452 if (tty == real_tty && current->signal->tty != real_tty)
2454 pid = tty_get_pgrp(real_tty);
2455 ret = put_user(pid_vnr(pid), p);
2461 * tiocspgrp - attempt to set process group
2462 * @tty: tty passed by user
2463 * @real_tty: tty side device matching tty passed by user
2466 * Set the process group of the tty to the session passed. Only
2467 * permitted where the tty session is our session.
2469 * Locking: RCU, ctrl lock
2472 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2476 int retval = tty_check_change(real_tty);
2477 unsigned long flags;
2483 if (!current->signal->tty ||
2484 (current->signal->tty != real_tty) ||
2485 (real_tty->session != task_session(current)))
2487 if (get_user(pgrp_nr, p))
2492 pgrp = find_vpid(pgrp_nr);
2497 if (session_of_pgrp(pgrp) != task_session(current))
2500 spin_lock_irqsave(&tty->ctrl_lock, flags);
2501 put_pid(real_tty->pgrp);
2502 real_tty->pgrp = get_pid(pgrp);
2503 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2510 * tiocgsid - get session id
2511 * @tty: tty passed by user
2512 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2513 * @p: pointer to returned session id
2515 * Obtain the session id of the tty. If there is no session
2518 * Locking: none. Reference to current->signal->tty is safe.
2521 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2524 * (tty == real_tty) is a cheap way of
2525 * testing if the tty is NOT a master pty.
2527 if (tty == real_tty && current->signal->tty != real_tty)
2529 if (!real_tty->session)
2531 return put_user(pid_vnr(real_tty->session), p);
2535 * tiocsetd - set line discipline
2537 * @p: pointer to user data
2539 * Set the line discipline according to user request.
2541 * Locking: see tty_set_ldisc, this function is just a helper
2544 static int tiocsetd(struct tty_struct *tty, int __user *p)
2549 if (get_user(ldisc, p))
2552 ret = tty_set_ldisc(tty, ldisc);
2558 * send_break - performed time break
2559 * @tty: device to break on
2560 * @duration: timeout in mS
2562 * Perform a timed break on hardware that lacks its own driver level
2563 * timed break functionality.
2566 * atomic_write_lock serializes
2570 static int send_break(struct tty_struct *tty, unsigned int duration)
2574 if (tty->ops->break_ctl == NULL)
2577 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2578 retval = tty->ops->break_ctl(tty, duration);
2580 /* Do the work ourselves */
2581 if (tty_write_lock(tty, 0) < 0)
2583 retval = tty->ops->break_ctl(tty, -1);
2586 if (!signal_pending(current))
2587 msleep_interruptible(duration);
2588 retval = tty->ops->break_ctl(tty, 0);
2590 tty_write_unlock(tty);
2591 if (signal_pending(current))
2598 * tty_tiocmget - get modem status
2600 * @file: user file pointer
2601 * @p: pointer to result
2603 * Obtain the modem status bits from the tty driver if the feature
2604 * is supported. Return -EINVAL if it is not available.
2606 * Locking: none (up to the driver)
2609 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2611 int retval = -EINVAL;
2613 if (tty->ops->tiocmget) {
2614 retval = tty->ops->tiocmget(tty);
2617 retval = put_user(retval, p);
2623 * tty_tiocmset - set modem status
2625 * @cmd: command - clear bits, set bits or set all
2626 * @p: pointer to desired bits
2628 * Set the modem status bits from the tty driver if the feature
2629 * is supported. Return -EINVAL if it is not available.
2631 * Locking: none (up to the driver)
2634 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2638 unsigned int set, clear, val;
2640 if (tty->ops->tiocmset == NULL)
2643 retval = get_user(val, p);
2659 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2660 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2661 return tty->ops->tiocmset(tty, set, clear);
2664 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2666 int retval = -EINVAL;
2667 struct serial_icounter_struct icount;
2668 memset(&icount, 0, sizeof(icount));
2669 if (tty->ops->get_icount)
2670 retval = tty->ops->get_icount(tty, &icount);
2673 if (copy_to_user(arg, &icount, sizeof(icount)))
2678 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2680 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2681 tty->driver->subtype == PTY_TYPE_MASTER)
2685 EXPORT_SYMBOL(tty_pair_get_tty);
2687 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2689 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2690 tty->driver->subtype == PTY_TYPE_MASTER)
2694 EXPORT_SYMBOL(tty_pair_get_pty);
2697 * Split this up, as gcc can choke on it otherwise..
2699 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2701 struct tty_struct *tty = file_tty(file);
2702 struct tty_struct *real_tty;
2703 void __user *p = (void __user *)arg;
2705 struct tty_ldisc *ld;
2707 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2710 real_tty = tty_pair_get_tty(tty);
2713 * Factor out some common prep work
2721 retval = tty_check_change(tty);
2724 if (cmd != TIOCCBRK) {
2725 tty_wait_until_sent(tty, 0);
2726 if (signal_pending(current))
2737 return tiocsti(tty, p);
2739 return tiocgwinsz(real_tty, p);
2741 return tiocswinsz(real_tty, p);
2743 return real_tty != tty ? -EINVAL : tioccons(file);
2745 return fionbio(file, p);
2747 set_bit(TTY_EXCLUSIVE, &tty->flags);
2750 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2754 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2755 return put_user(excl, (int __user *)p);
2758 if (current->signal->tty != tty)
2763 return tiocsctty(tty, arg);
2765 return tiocgpgrp(tty, real_tty, p);
2767 return tiocspgrp(tty, real_tty, p);
2769 return tiocgsid(tty, real_tty, p);
2771 return put_user(tty->ldisc->ops->num, (int __user *)p);
2773 return tiocsetd(tty, p);
2775 if (!capable(CAP_SYS_ADMIN))
2781 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2782 return put_user(ret, (unsigned int __user *)p);
2787 case TIOCSBRK: /* Turn break on, unconditionally */
2788 if (tty->ops->break_ctl)
2789 return tty->ops->break_ctl(tty, -1);
2791 case TIOCCBRK: /* Turn break off, unconditionally */
2792 if (tty->ops->break_ctl)
2793 return tty->ops->break_ctl(tty, 0);
2795 case TCSBRK: /* SVID version: non-zero arg --> no break */
2796 /* non-zero arg means wait for all output data
2797 * to be sent (performed above) but don't send break.
2798 * This is used by the tcdrain() termios function.
2801 return send_break(tty, 250);
2803 case TCSBRKP: /* support for POSIX tcsendbreak() */
2804 return send_break(tty, arg ? arg*100 : 250);
2807 return tty_tiocmget(tty, p);
2811 return tty_tiocmset(tty, cmd, p);
2813 retval = tty_tiocgicount(tty, p);
2814 /* For the moment allow fall through to the old method */
2815 if (retval != -EINVAL)
2822 /* flush tty buffer and allow ldisc to process ioctl */
2823 tty_buffer_flush(tty);
2828 if (tty->ops->ioctl) {
2829 retval = (tty->ops->ioctl)(tty, cmd, arg);
2830 if (retval != -ENOIOCTLCMD)
2833 ld = tty_ldisc_ref_wait(tty);
2835 if (ld->ops->ioctl) {
2836 retval = ld->ops->ioctl(tty, file, cmd, arg);
2837 if (retval == -ENOIOCTLCMD)
2840 tty_ldisc_deref(ld);
2844 #ifdef CONFIG_COMPAT
2845 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2848 struct tty_struct *tty = file_tty(file);
2849 struct tty_ldisc *ld;
2850 int retval = -ENOIOCTLCMD;
2852 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2855 if (tty->ops->compat_ioctl) {
2856 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2857 if (retval != -ENOIOCTLCMD)
2861 ld = tty_ldisc_ref_wait(tty);
2862 if (ld->ops->compat_ioctl)
2863 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2865 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2866 tty_ldisc_deref(ld);
2872 static int this_tty(const void *t, struct file *file, unsigned fd)
2874 if (likely(file->f_op->read != tty_read))
2876 return file_tty(file) != t ? 0 : fd + 1;
2880 * This implements the "Secure Attention Key" --- the idea is to
2881 * prevent trojan horses by killing all processes associated with this
2882 * tty when the user hits the "Secure Attention Key". Required for
2883 * super-paranoid applications --- see the Orange Book for more details.
2885 * This code could be nicer; ideally it should send a HUP, wait a few
2886 * seconds, then send a INT, and then a KILL signal. But you then
2887 * have to coordinate with the init process, since all processes associated
2888 * with the current tty must be dead before the new getty is allowed
2891 * Now, if it would be correct ;-/ The current code has a nasty hole -
2892 * it doesn't catch files in flight. We may send the descriptor to ourselves
2893 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2895 * Nasty bug: do_SAK is being called in interrupt context. This can
2896 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2898 void __do_SAK(struct tty_struct *tty)
2903 struct task_struct *g, *p;
2904 struct pid *session;
2909 session = tty->session;
2911 tty_ldisc_flush(tty);
2913 tty_driver_flush_buffer(tty);
2915 read_lock(&tasklist_lock);
2916 /* Kill the entire session */
2917 do_each_pid_task(session, PIDTYPE_SID, p) {
2918 printk(KERN_NOTICE "SAK: killed process %d"
2919 " (%s): task_session(p)==tty->session\n",
2920 task_pid_nr(p), p->comm);
2921 send_sig(SIGKILL, p, 1);
2922 } while_each_pid_task(session, PIDTYPE_SID, p);
2923 /* Now kill any processes that happen to have the
2926 do_each_thread(g, p) {
2927 if (p->signal->tty == tty) {
2928 printk(KERN_NOTICE "SAK: killed process %d"
2929 " (%s): task_session(p)==tty->session\n",
2930 task_pid_nr(p), p->comm);
2931 send_sig(SIGKILL, p, 1);
2935 i = iterate_fd(p->files, 0, this_tty, tty);
2937 printk(KERN_NOTICE "SAK: killed process %d"
2938 " (%s): fd#%d opened to the tty\n",
2939 task_pid_nr(p), p->comm, i - 1);
2940 force_sig(SIGKILL, p);
2943 } while_each_thread(g, p);
2944 read_unlock(&tasklist_lock);
2948 static void do_SAK_work(struct work_struct *work)
2950 struct tty_struct *tty =
2951 container_of(work, struct tty_struct, SAK_work);
2956 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2957 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2958 * the values which we write to it will be identical to the values which it
2959 * already has. --akpm
2961 void do_SAK(struct tty_struct *tty)
2965 schedule_work(&tty->SAK_work);
2968 EXPORT_SYMBOL(do_SAK);
2970 static int dev_match_devt(struct device *dev, const void *data)
2972 const dev_t *devt = data;
2973 return dev->devt == *devt;
2976 /* Must put_device() after it's unused! */
2977 static struct device *tty_get_device(struct tty_struct *tty)
2979 dev_t devt = tty_devnum(tty);
2980 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2987 * This subroutine allocates and initializes a tty structure.
2989 * Locking: none - tty in question is not exposed at this point
2992 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
2994 struct tty_struct *tty;
2996 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3000 kref_init(&tty->kref);
3001 tty->magic = TTY_MAGIC;
3002 tty_ldisc_init(tty);
3003 tty->session = NULL;
3005 mutex_init(&tty->legacy_mutex);
3006 mutex_init(&tty->throttle_mutex);
3007 init_rwsem(&tty->termios_rwsem);
3008 mutex_init(&tty->winsize_mutex);
3009 init_ldsem(&tty->ldisc_sem);
3010 init_waitqueue_head(&tty->write_wait);
3011 init_waitqueue_head(&tty->read_wait);
3012 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3013 mutex_init(&tty->atomic_write_lock);
3014 spin_lock_init(&tty->ctrl_lock);
3015 spin_lock_init(&tty->flow_lock);
3016 INIT_LIST_HEAD(&tty->tty_files);
3017 INIT_WORK(&tty->SAK_work, do_SAK_work);
3019 tty->driver = driver;
3020 tty->ops = driver->ops;
3022 tty_line_name(driver, idx, tty->name);
3023 tty->dev = tty_get_device(tty);
3029 * deinitialize_tty_struct
3030 * @tty: tty to deinitialize
3032 * This subroutine deinitializes a tty structure that has been newly
3033 * allocated but tty_release cannot be called on that yet.
3035 * Locking: none - tty in question must not be exposed at this point
3037 void deinitialize_tty_struct(struct tty_struct *tty)
3039 tty_ldisc_deinit(tty);
3043 * tty_put_char - write one character to a tty
3047 * Write one byte to the tty using the provided put_char method
3048 * if present. Returns the number of characters successfully output.
3050 * Note: the specific put_char operation in the driver layer may go
3051 * away soon. Don't call it directly, use this method
3054 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3056 if (tty->ops->put_char)
3057 return tty->ops->put_char(tty, ch);
3058 return tty->ops->write(tty, &ch, 1);
3060 EXPORT_SYMBOL_GPL(tty_put_char);
3062 struct class *tty_class;
3064 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3065 unsigned int index, unsigned int count)
3067 /* init here, since reused cdevs cause crashes */
3068 cdev_init(&driver->cdevs[index], &tty_fops);
3069 driver->cdevs[index].owner = driver->owner;
3070 return cdev_add(&driver->cdevs[index], dev, count);
3074 * tty_register_device - register a tty device
3075 * @driver: the tty driver that describes the tty device
3076 * @index: the index in the tty driver for this tty device
3077 * @device: a struct device that is associated with this tty device.
3078 * This field is optional, if there is no known struct device
3079 * for this tty device it can be set to NULL safely.
3081 * Returns a pointer to the struct device for this tty device
3082 * (or ERR_PTR(-EFOO) on error).
3084 * This call is required to be made to register an individual tty device
3085 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3086 * that bit is not set, this function should not be called by a tty
3092 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3093 struct device *device)
3095 return tty_register_device_attr(driver, index, device, NULL, NULL);
3097 EXPORT_SYMBOL(tty_register_device);
3099 static void tty_device_create_release(struct device *dev)
3101 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3106 * tty_register_device_attr - register a tty device
3107 * @driver: the tty driver that describes the tty device
3108 * @index: the index in the tty driver for this tty device
3109 * @device: a struct device that is associated with this tty device.
3110 * This field is optional, if there is no known struct device
3111 * for this tty device it can be set to NULL safely.
3112 * @drvdata: Driver data to be set to device.
3113 * @attr_grp: Attribute group to be set on device.
3115 * Returns a pointer to the struct device for this tty device
3116 * (or ERR_PTR(-EFOO) on error).
3118 * This call is required to be made to register an individual tty device
3119 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3120 * that bit is not set, this function should not be called by a tty
3125 struct device *tty_register_device_attr(struct tty_driver *driver,
3126 unsigned index, struct device *device,
3128 const struct attribute_group **attr_grp)
3131 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3132 struct device *dev = NULL;
3133 int retval = -ENODEV;
3136 if (index >= driver->num) {
3137 printk(KERN_ERR "Attempt to register invalid tty line number "
3139 return ERR_PTR(-EINVAL);
3142 if (driver->type == TTY_DRIVER_TYPE_PTY)
3143 pty_line_name(driver, index, name);
3145 tty_line_name(driver, index, name);
3147 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3148 retval = tty_cdev_add(driver, devt, index, 1);
3154 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3161 dev->class = tty_class;
3162 dev->parent = device;
3163 dev->release = tty_device_create_release;
3164 dev_set_name(dev, "%s", name);
3165 dev->groups = attr_grp;
3166 dev_set_drvdata(dev, drvdata);
3168 retval = device_register(dev);
3177 cdev_del(&driver->cdevs[index]);
3178 return ERR_PTR(retval);
3180 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3183 * tty_unregister_device - unregister a tty device
3184 * @driver: the tty driver that describes the tty device
3185 * @index: the index in the tty driver for this tty device
3187 * If a tty device is registered with a call to tty_register_device() then
3188 * this function must be called when the tty device is gone.
3193 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3195 device_destroy(tty_class,
3196 MKDEV(driver->major, driver->minor_start) + index);
3197 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3198 cdev_del(&driver->cdevs[index]);
3200 EXPORT_SYMBOL(tty_unregister_device);
3203 * __tty_alloc_driver -- allocate tty driver
3204 * @lines: count of lines this driver can handle at most
3205 * @owner: module which is repsonsible for this driver
3206 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3208 * This should not be called directly, some of the provided macros should be
3209 * used instead. Use IS_ERR and friends on @retval.
3211 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3212 unsigned long flags)
3214 struct tty_driver *driver;
3215 unsigned int cdevs = 1;
3218 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3219 return ERR_PTR(-EINVAL);
3221 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3223 return ERR_PTR(-ENOMEM);
3225 kref_init(&driver->kref);
3226 driver->magic = TTY_DRIVER_MAGIC;
3227 driver->num = lines;
3228 driver->owner = owner;
3229 driver->flags = flags;
3231 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3232 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3234 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3236 if (!driver->ttys || !driver->termios) {
3242 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3243 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3245 if (!driver->ports) {
3252 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3253 if (!driver->cdevs) {
3260 kfree(driver->ports);
3261 kfree(driver->ttys);
3262 kfree(driver->termios);
3264 return ERR_PTR(err);
3266 EXPORT_SYMBOL(__tty_alloc_driver);
3268 static void destruct_tty_driver(struct kref *kref)
3270 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3272 struct ktermios *tp;
3274 if (driver->flags & TTY_DRIVER_INSTALLED) {
3276 * Free the termios and termios_locked structures because
3277 * we don't want to get memory leaks when modular tty
3278 * drivers are removed from the kernel.
3280 for (i = 0; i < driver->num; i++) {
3281 tp = driver->termios[i];
3283 driver->termios[i] = NULL;
3286 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3287 tty_unregister_device(driver, i);
3289 proc_tty_unregister_driver(driver);
3290 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3291 cdev_del(&driver->cdevs[0]);
3293 kfree(driver->cdevs);
3294 kfree(driver->ports);
3295 kfree(driver->termios);
3296 kfree(driver->ttys);
3300 void tty_driver_kref_put(struct tty_driver *driver)
3302 kref_put(&driver->kref, destruct_tty_driver);
3304 EXPORT_SYMBOL(tty_driver_kref_put);
3306 void tty_set_operations(struct tty_driver *driver,
3307 const struct tty_operations *op)
3311 EXPORT_SYMBOL(tty_set_operations);
3313 void put_tty_driver(struct tty_driver *d)
3315 tty_driver_kref_put(d);
3317 EXPORT_SYMBOL(put_tty_driver);
3320 * Called by a tty driver to register itself.
3322 int tty_register_driver(struct tty_driver *driver)
3329 if (!driver->major) {
3330 error = alloc_chrdev_region(&dev, driver->minor_start,
3331 driver->num, driver->name);
3333 driver->major = MAJOR(dev);
3334 driver->minor_start = MINOR(dev);
3337 dev = MKDEV(driver->major, driver->minor_start);
3338 error = register_chrdev_region(dev, driver->num, driver->name);
3343 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3344 error = tty_cdev_add(driver, dev, 0, driver->num);
3346 goto err_unreg_char;
3349 mutex_lock(&tty_mutex);
3350 list_add(&driver->tty_drivers, &tty_drivers);
3351 mutex_unlock(&tty_mutex);
3353 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3354 for (i = 0; i < driver->num; i++) {
3355 d = tty_register_device(driver, i, NULL);
3358 goto err_unreg_devs;
3362 proc_tty_register_driver(driver);
3363 driver->flags |= TTY_DRIVER_INSTALLED;
3367 for (i--; i >= 0; i--)
3368 tty_unregister_device(driver, i);
3370 mutex_lock(&tty_mutex);
3371 list_del(&driver->tty_drivers);
3372 mutex_unlock(&tty_mutex);
3375 unregister_chrdev_region(dev, driver->num);
3379 EXPORT_SYMBOL(tty_register_driver);
3382 * Called by a tty driver to unregister itself.
3384 int tty_unregister_driver(struct tty_driver *driver)
3388 if (driver->refcount)
3391 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3393 mutex_lock(&tty_mutex);
3394 list_del(&driver->tty_drivers);
3395 mutex_unlock(&tty_mutex);
3399 EXPORT_SYMBOL(tty_unregister_driver);
3401 dev_t tty_devnum(struct tty_struct *tty)
3403 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3405 EXPORT_SYMBOL(tty_devnum);
3407 void proc_clear_tty(struct task_struct *p)
3409 unsigned long flags;
3410 struct tty_struct *tty;
3411 spin_lock_irqsave(&p->sighand->siglock, flags);
3412 tty = p->signal->tty;
3413 p->signal->tty = NULL;
3414 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3418 /* Called under the sighand lock */
3420 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3423 unsigned long flags;
3424 /* We should not have a session or pgrp to put here but.... */
3425 spin_lock_irqsave(&tty->ctrl_lock, flags);
3426 put_pid(tty->session);
3428 tty->pgrp = get_pid(task_pgrp(tsk));
3429 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3430 tty->session = get_pid(task_session(tsk));
3431 if (tsk->signal->tty) {
3432 printk(KERN_DEBUG "tty not NULL!!\n");
3433 tty_kref_put(tsk->signal->tty);
3436 put_pid(tsk->signal->tty_old_pgrp);
3437 tsk->signal->tty = tty_kref_get(tty);
3438 tsk->signal->tty_old_pgrp = NULL;
3441 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3443 spin_lock_irq(&tsk->sighand->siglock);
3444 __proc_set_tty(tsk, tty);
3445 spin_unlock_irq(&tsk->sighand->siglock);
3448 struct tty_struct *get_current_tty(void)
3450 struct tty_struct *tty;
3451 unsigned long flags;
3453 spin_lock_irqsave(¤t->sighand->siglock, flags);
3454 tty = tty_kref_get(current->signal->tty);
3455 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3458 EXPORT_SYMBOL_GPL(get_current_tty);
3460 void tty_default_fops(struct file_operations *fops)
3466 * Initialize the console device. This is called *early*, so
3467 * we can't necessarily depend on lots of kernel help here.
3468 * Just do some early initializations, and do the complex setup
3471 void __init console_init(void)
3475 /* Setup the default TTY line discipline. */
3479 * set up the console device so that later boot sequences can
3480 * inform about problems etc..
3482 call = __con_initcall_start;
3483 while (call < __con_initcall_end) {
3489 static char *tty_devnode(struct device *dev, umode_t *mode)
3493 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3494 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3499 static int __init tty_class_init(void)
3501 tty_class = class_create(THIS_MODULE, "tty");
3502 if (IS_ERR(tty_class))
3503 return PTR_ERR(tty_class);
3504 tty_class->devnode = tty_devnode;
3508 postcore_initcall(tty_class_init);
3510 /* 3/2004 jmc: why do these devices exist? */
3511 static struct cdev tty_cdev, console_cdev;
3513 static ssize_t show_cons_active(struct device *dev,
3514 struct device_attribute *attr, char *buf)
3516 struct console *cs[16];
3522 for_each_console(c) {
3527 if ((c->flags & CON_ENABLED) == 0)
3530 if (i >= ARRAY_SIZE(cs))
3534 int index = cs[i]->index;
3535 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3537 /* don't resolve tty0 as some programs depend on it */
3538 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3539 count += tty_line_name(drv, index, buf + count);
3541 count += sprintf(buf + count, "%s%d",
3542 cs[i]->name, cs[i]->index);
3544 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3550 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3552 static struct device *consdev;
3554 void console_sysfs_notify(void)
3557 sysfs_notify(&consdev->kobj, NULL, "active");
3561 * Ok, now we can initialize the rest of the tty devices and can count
3562 * on memory allocations, interrupts etc..
3564 int __init tty_init(void)
3566 cdev_init(&tty_cdev, &tty_fops);
3567 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3568 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3569 panic("Couldn't register /dev/tty driver\n");
3570 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3572 cdev_init(&console_cdev, &console_fops);
3573 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3574 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3575 panic("Couldn't register /dev/console driver\n");
3576 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3578 if (IS_ERR(consdev))
3581 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3584 vty_init(&console_fops);