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 * alloc_tty_struct - allocate a tty object
162 * Return a new empty tty structure. The data fields have not
163 * been initialized in any way but has been zeroed
168 struct tty_struct *alloc_tty_struct(void)
170 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
174 * free_tty_struct - free a disused tty
175 * @tty: tty struct to free
177 * Free the write buffers, tty queue and tty memory itself.
179 * Locking: none. Must be called after tty is definitely unused
182 void free_tty_struct(struct tty_struct *tty)
187 put_device(tty->dev);
188 kfree(tty->write_buf);
189 tty->magic = 0xDEADDEAD;
193 static inline struct tty_struct *file_tty(struct file *file)
195 return ((struct tty_file_private *)file->private_data)->tty;
198 int tty_alloc_file(struct file *file)
200 struct tty_file_private *priv;
202 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
206 file->private_data = priv;
211 /* Associate a new file with the tty structure */
212 void tty_add_file(struct tty_struct *tty, struct file *file)
214 struct tty_file_private *priv = file->private_data;
219 spin_lock(&tty_files_lock);
220 list_add(&priv->list, &tty->tty_files);
221 spin_unlock(&tty_files_lock);
225 * tty_free_file - free file->private_data
227 * This shall be used only for fail path handling when tty_add_file was not
230 void tty_free_file(struct file *file)
232 struct tty_file_private *priv = file->private_data;
234 file->private_data = NULL;
238 /* Delete file from its tty */
239 static void tty_del_file(struct file *file)
241 struct tty_file_private *priv = file->private_data;
243 spin_lock(&tty_files_lock);
244 list_del(&priv->list);
245 spin_unlock(&tty_files_lock);
250 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
253 * tty_name - return tty naming
254 * @tty: tty structure
255 * @buf: buffer for output
257 * Convert a tty structure into a name. The name reflects the kernel
258 * naming policy and if udev is in use may not reflect user space
263 char *tty_name(struct tty_struct *tty, char *buf)
265 if (!tty) /* Hmm. NULL pointer. That's fun. */
266 strcpy(buf, "NULL tty");
268 strcpy(buf, tty->name);
272 EXPORT_SYMBOL(tty_name);
274 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
277 #ifdef TTY_PARANOIA_CHECK
280 "null TTY for (%d:%d) in %s\n",
281 imajor(inode), iminor(inode), routine);
284 if (tty->magic != TTY_MAGIC) {
286 "bad magic number for tty struct (%d:%d) in %s\n",
287 imajor(inode), iminor(inode), routine);
294 static int check_tty_count(struct tty_struct *tty, const char *routine)
296 #ifdef CHECK_TTY_COUNT
300 spin_lock(&tty_files_lock);
301 list_for_each(p, &tty->tty_files) {
304 spin_unlock(&tty_files_lock);
305 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
306 tty->driver->subtype == PTY_TYPE_SLAVE &&
307 tty->link && tty->link->count)
309 if (tty->count != count) {
310 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
311 "!= #fd's(%d) in %s\n",
312 tty->name, tty->count, count, routine);
320 * get_tty_driver - find device of a tty
321 * @dev_t: device identifier
322 * @index: returns the index of the tty
324 * This routine returns a tty driver structure, given a device number
325 * and also passes back the index number.
327 * Locking: caller must hold tty_mutex
330 static struct tty_driver *get_tty_driver(dev_t device, int *index)
332 struct tty_driver *p;
334 list_for_each_entry(p, &tty_drivers, tty_drivers) {
335 dev_t base = MKDEV(p->major, p->minor_start);
336 if (device < base || device >= base + p->num)
338 *index = device - base;
339 return tty_driver_kref_get(p);
344 #ifdef CONFIG_CONSOLE_POLL
347 * tty_find_polling_driver - find device of a polled tty
348 * @name: name string to match
349 * @line: pointer to resulting tty line nr
351 * This routine returns a tty driver structure, given a name
352 * and the condition that the tty driver is capable of polled
355 struct tty_driver *tty_find_polling_driver(char *name, int *line)
357 struct tty_driver *p, *res = NULL;
362 for (str = name; *str; str++)
363 if ((*str >= '0' && *str <= '9') || *str == ',')
369 tty_line = simple_strtoul(str, &str, 10);
371 mutex_lock(&tty_mutex);
372 /* Search through the tty devices to look for a match */
373 list_for_each_entry(p, &tty_drivers, tty_drivers) {
374 if (strncmp(name, p->name, len) != 0)
382 if (tty_line >= 0 && tty_line < p->num && p->ops &&
383 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
384 res = tty_driver_kref_get(p);
389 mutex_unlock(&tty_mutex);
393 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
397 * tty_check_change - check for POSIX terminal changes
400 * If we try to write to, or set the state of, a terminal and we're
401 * not in the foreground, send a SIGTTOU. If the signal is blocked or
402 * ignored, go ahead and perform the operation. (POSIX 7.2)
407 int tty_check_change(struct tty_struct *tty)
412 if (current->signal->tty != tty)
415 spin_lock_irqsave(&tty->ctrl_lock, flags);
418 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
421 if (task_pgrp(current) == tty->pgrp)
423 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
424 if (is_ignored(SIGTTOU))
426 if (is_current_pgrp_orphaned()) {
430 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
431 set_thread_flag(TIF_SIGPENDING);
436 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
440 EXPORT_SYMBOL(tty_check_change);
442 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
443 size_t count, loff_t *ppos)
448 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
449 size_t count, loff_t *ppos)
454 /* No kernel lock held - none needed ;) */
455 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
457 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
460 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
463 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
466 static long hung_up_tty_compat_ioctl(struct file *file,
467 unsigned int cmd, unsigned long arg)
469 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
472 static const struct file_operations tty_fops = {
477 .unlocked_ioctl = tty_ioctl,
478 .compat_ioctl = tty_compat_ioctl,
480 .release = tty_release,
481 .fasync = tty_fasync,
484 static const struct file_operations console_fops = {
487 .write = redirected_tty_write,
489 .unlocked_ioctl = tty_ioctl,
490 .compat_ioctl = tty_compat_ioctl,
492 .release = tty_release,
493 .fasync = tty_fasync,
496 static const struct file_operations hung_up_tty_fops = {
498 .read = hung_up_tty_read,
499 .write = hung_up_tty_write,
500 .poll = hung_up_tty_poll,
501 .unlocked_ioctl = hung_up_tty_ioctl,
502 .compat_ioctl = hung_up_tty_compat_ioctl,
503 .release = tty_release,
506 static DEFINE_SPINLOCK(redirect_lock);
507 static struct file *redirect;
510 * tty_wakeup - request more data
513 * Internal and external helper for wakeups of tty. This function
514 * informs the line discipline if present that the driver is ready
515 * to receive more output data.
518 void tty_wakeup(struct tty_struct *tty)
520 struct tty_ldisc *ld;
522 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
523 ld = tty_ldisc_ref(tty);
525 if (ld->ops->write_wakeup)
526 ld->ops->write_wakeup(tty);
530 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
533 EXPORT_SYMBOL_GPL(tty_wakeup);
536 * tty_signal_session_leader - sends SIGHUP to session leader
538 * Send SIGHUP and SIGCONT to the session leader and its
541 * Returns the number of processes in the session with this tty
542 * as their controlling terminal. This value is used to drop
543 * tty references for those processes.
545 static int tty_signal_session_leader(struct tty_struct *tty)
547 struct task_struct *p;
550 read_lock(&tasklist_lock);
552 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
553 spin_lock_irq(&p->sighand->siglock);
554 if (p->signal->tty == tty) {
555 p->signal->tty = NULL;
556 /* We defer the dereferences outside fo
560 if (!p->signal->leader) {
561 spin_unlock_irq(&p->sighand->siglock);
564 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
565 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
566 put_pid(p->signal->tty_old_pgrp); /* A noop */
567 spin_lock(&tty->ctrl_lock);
569 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
570 spin_unlock(&tty->ctrl_lock);
571 spin_unlock_irq(&p->sighand->siglock);
572 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
574 read_unlock(&tasklist_lock);
580 * __tty_hangup - actual handler for hangup events
583 * This can be called by a "kworker" kernel thread. That is process
584 * synchronous but doesn't hold any locks, so we need to make sure we
585 * have the appropriate locks for what we're doing.
587 * The hangup event clears any pending redirections onto the hung up
588 * device. It ensures future writes will error and it does the needed
589 * line discipline hangup and signal delivery. The tty object itself
594 * redirect lock for undoing redirection
595 * file list lock for manipulating list of ttys
596 * tty_ldisc_lock from called functions
597 * termios_mutex resetting termios data
598 * tasklist_lock to walk task list for hangup event
599 * ->siglock to protect ->signal/->sighand
601 static void __tty_hangup(struct tty_struct *tty)
603 struct file *cons_filp = NULL;
604 struct file *filp, *f = NULL;
605 struct tty_file_private *priv;
606 int closecount = 0, n;
613 spin_lock(&redirect_lock);
614 if (redirect && file_tty(redirect) == tty) {
618 spin_unlock(&redirect_lock);
622 /* some functions below drop BTM, so we need this bit */
623 set_bit(TTY_HUPPING, &tty->flags);
625 /* inuse_filps is protected by the single tty lock,
626 this really needs to change if we want to flush the
627 workqueue with the lock held */
628 check_tty_count(tty, "tty_hangup");
630 spin_lock(&tty_files_lock);
631 /* This breaks for file handles being sent over AF_UNIX sockets ? */
632 list_for_each_entry(priv, &tty->tty_files, list) {
634 if (filp->f_op->write == redirected_tty_write)
636 if (filp->f_op->write != tty_write)
639 __tty_fasync(-1, filp, 0); /* can't block */
640 filp->f_op = &hung_up_tty_fops;
642 spin_unlock(&tty_files_lock);
645 * it drops BTM and thus races with reopen
646 * we protect the race by TTY_HUPPING
648 tty_ldisc_hangup(tty);
650 refs = tty_signal_session_leader(tty);
651 /* Account for the p->signal references we killed */
655 spin_lock_irq(&tty->ctrl_lock);
656 clear_bit(TTY_THROTTLED, &tty->flags);
657 clear_bit(TTY_PUSH, &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);
686 tty_ldisc_enable(tty);
694 static void do_tty_hangup(struct work_struct *work)
696 struct tty_struct *tty =
697 container_of(work, struct tty_struct, hangup_work);
703 * tty_hangup - trigger a hangup event
704 * @tty: tty to hangup
706 * A carrier loss (virtual or otherwise) has occurred on this like
707 * schedule a hangup sequence to run after this event.
710 void tty_hangup(struct tty_struct *tty)
712 #ifdef TTY_DEBUG_HANGUP
714 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
716 schedule_work(&tty->hangup_work);
719 EXPORT_SYMBOL(tty_hangup);
722 * tty_vhangup - process vhangup
723 * @tty: tty to hangup
725 * The user has asked via system call for the terminal to be hung up.
726 * We do this synchronously so that when the syscall returns the process
727 * is complete. That guarantee is necessary for security reasons.
730 void tty_vhangup(struct tty_struct *tty)
732 #ifdef TTY_DEBUG_HANGUP
735 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
740 EXPORT_SYMBOL(tty_vhangup);
744 * tty_vhangup_self - process vhangup for own ctty
746 * Perform a vhangup on the current controlling tty
749 void tty_vhangup_self(void)
751 struct tty_struct *tty;
753 tty = get_current_tty();
761 * tty_hung_up_p - was tty hung up
762 * @filp: file pointer of tty
764 * Return true if the tty has been subject to a vhangup or a carrier
768 int tty_hung_up_p(struct file *filp)
770 return (filp->f_op == &hung_up_tty_fops);
773 EXPORT_SYMBOL(tty_hung_up_p);
775 static void session_clear_tty(struct pid *session)
777 struct task_struct *p;
778 do_each_pid_task(session, PIDTYPE_SID, p) {
780 } while_each_pid_task(session, PIDTYPE_SID, p);
784 * disassociate_ctty - disconnect controlling tty
785 * @on_exit: true if exiting so need to "hang up" the session
787 * This function is typically called only by the session leader, when
788 * it wants to disassociate itself from its controlling tty.
790 * It performs the following functions:
791 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
792 * (2) Clears the tty from being controlling the session
793 * (3) Clears the controlling tty for all processes in the
796 * The argument on_exit is set to 1 if called when a process is
797 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
800 * BTM is taken for hysterical raisins, and held when
801 * called from no_tty().
802 * tty_mutex is taken to protect tty
803 * ->siglock is taken to protect ->signal/->sighand
804 * tasklist_lock is taken to walk process list for sessions
805 * ->siglock is taken to protect ->signal/->sighand
808 void disassociate_ctty(int on_exit)
810 struct tty_struct *tty;
812 if (!current->signal->leader)
815 tty = get_current_tty();
817 struct pid *tty_pgrp = get_pid(tty->pgrp);
819 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
824 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
826 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
829 } else if (on_exit) {
830 struct pid *old_pgrp;
831 spin_lock_irq(¤t->sighand->siglock);
832 old_pgrp = current->signal->tty_old_pgrp;
833 current->signal->tty_old_pgrp = NULL;
834 spin_unlock_irq(¤t->sighand->siglock);
836 kill_pgrp(old_pgrp, SIGHUP, on_exit);
837 kill_pgrp(old_pgrp, SIGCONT, on_exit);
843 spin_lock_irq(¤t->sighand->siglock);
844 put_pid(current->signal->tty_old_pgrp);
845 current->signal->tty_old_pgrp = NULL;
846 spin_unlock_irq(¤t->sighand->siglock);
848 tty = get_current_tty();
851 spin_lock_irqsave(&tty->ctrl_lock, flags);
852 put_pid(tty->session);
856 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
859 #ifdef TTY_DEBUG_HANGUP
860 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
865 /* Now clear signal->tty under the lock */
866 read_lock(&tasklist_lock);
867 session_clear_tty(task_session(current));
868 read_unlock(&tasklist_lock);
873 * no_tty - Ensure the current process does not have a controlling tty
877 /* FIXME: Review locking here. The tty_lock never covered any race
878 between a new association and proc_clear_tty but possible we need
879 to protect against this anyway */
880 struct task_struct *tsk = current;
881 disassociate_ctty(0);
887 * stop_tty - propagate flow control
890 * Perform flow control to the driver. For PTY/TTY pairs we
891 * must also propagate the TIOCKPKT status. May be called
892 * on an already stopped device and will not re-call the driver
895 * This functionality is used by both the line disciplines for
896 * halting incoming flow and by the driver. It may therefore be
897 * called from any context, may be under the tty atomic_write_lock
901 * Uses the tty control lock internally
904 void stop_tty(struct tty_struct *tty)
907 spin_lock_irqsave(&tty->ctrl_lock, flags);
909 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
913 if (tty->link && tty->link->packet) {
914 tty->ctrl_status &= ~TIOCPKT_START;
915 tty->ctrl_status |= TIOCPKT_STOP;
916 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
918 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
920 (tty->ops->stop)(tty);
923 EXPORT_SYMBOL(stop_tty);
926 * start_tty - propagate flow control
929 * Start a tty that has been stopped if at all possible. Perform
930 * any necessary wakeups and propagate the TIOCPKT status. If this
931 * is the tty was previous stopped and is being started then the
932 * driver start method is invoked and the line discipline woken.
938 void start_tty(struct tty_struct *tty)
941 spin_lock_irqsave(&tty->ctrl_lock, flags);
942 if (!tty->stopped || tty->flow_stopped) {
943 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
947 if (tty->link && tty->link->packet) {
948 tty->ctrl_status &= ~TIOCPKT_STOP;
949 tty->ctrl_status |= TIOCPKT_START;
950 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
952 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
954 (tty->ops->start)(tty);
955 /* If we have a running line discipline it may need kicking */
959 EXPORT_SYMBOL(start_tty);
962 * tty_read - read method for tty device files
963 * @file: pointer to tty file
965 * @count: size of user buffer
968 * Perform the read system call function on this terminal device. Checks
969 * for hung up devices before calling the line discipline method.
972 * Locks the line discipline internally while needed. Multiple
973 * read calls may be outstanding in parallel.
976 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
980 struct tty_struct *tty = file_tty(file);
981 struct tty_ldisc *ld;
983 if (tty_paranoia_check(tty, file_inode(file), "tty_read"))
985 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
988 /* We want to wait for the line discipline to sort out in this
990 ld = tty_ldisc_ref_wait(tty);
992 i = (ld->ops->read)(tty, file, buf, count);
1000 void tty_write_unlock(struct tty_struct *tty)
1001 __releases(&tty->atomic_write_lock)
1003 mutex_unlock(&tty->atomic_write_lock);
1004 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1007 int tty_write_lock(struct tty_struct *tty, int ndelay)
1008 __acquires(&tty->atomic_write_lock)
1010 if (!mutex_trylock(&tty->atomic_write_lock)) {
1013 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1014 return -ERESTARTSYS;
1020 * Split writes up in sane blocksizes to avoid
1021 * denial-of-service type attacks
1023 static inline ssize_t do_tty_write(
1024 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1025 struct tty_struct *tty,
1027 const char __user *buf,
1030 ssize_t ret, written = 0;
1033 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1038 * We chunk up writes into a temporary buffer. This
1039 * simplifies low-level drivers immensely, since they
1040 * don't have locking issues and user mode accesses.
1042 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1045 * The default chunk-size is 2kB, because the NTTY
1046 * layer has problems with bigger chunks. It will
1047 * claim to be able to handle more characters than
1050 * FIXME: This can probably go away now except that 64K chunks
1051 * are too likely to fail unless switched to vmalloc...
1054 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1059 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1060 if (tty->write_cnt < chunk) {
1061 unsigned char *buf_chunk;
1066 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1071 kfree(tty->write_buf);
1072 tty->write_cnt = chunk;
1073 tty->write_buf = buf_chunk;
1076 /* Do the write .. */
1078 size_t size = count;
1082 if (copy_from_user(tty->write_buf, buf, size))
1084 ret = write(tty, file, tty->write_buf, size);
1093 if (signal_pending(current))
1100 tty_write_unlock(tty);
1105 * tty_write_message - write a message to a certain tty, not just the console.
1106 * @tty: the destination tty_struct
1107 * @msg: the message to write
1109 * This is used for messages that need to be redirected to a specific tty.
1110 * We don't put it into the syslog queue right now maybe in the future if
1113 * We must still hold the BTM and test the CLOSING flag for the moment.
1116 void tty_write_message(struct tty_struct *tty, char *msg)
1119 mutex_lock(&tty->atomic_write_lock);
1121 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1123 tty->ops->write(tty, msg, strlen(msg));
1126 tty_write_unlock(tty);
1133 * tty_write - write method for tty device file
1134 * @file: tty file pointer
1135 * @buf: user data to write
1136 * @count: bytes to write
1139 * Write data to a tty device via the line discipline.
1142 * Locks the line discipline as required
1143 * Writes to the tty driver are serialized by the atomic_write_lock
1144 * and are then processed in chunks to the device. The line discipline
1145 * write method will not be invoked in parallel for each device.
1148 static ssize_t tty_write(struct file *file, const char __user *buf,
1149 size_t count, loff_t *ppos)
1151 struct tty_struct *tty = file_tty(file);
1152 struct tty_ldisc *ld;
1155 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1157 if (!tty || !tty->ops->write ||
1158 (test_bit(TTY_IO_ERROR, &tty->flags)))
1160 /* Short term debug to catch buggy drivers */
1161 if (tty->ops->write_room == NULL)
1162 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1164 ld = tty_ldisc_ref_wait(tty);
1165 if (!ld->ops->write)
1168 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1169 tty_ldisc_deref(ld);
1173 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1174 size_t count, loff_t *ppos)
1176 struct file *p = NULL;
1178 spin_lock(&redirect_lock);
1180 p = get_file(redirect);
1181 spin_unlock(&redirect_lock);
1185 res = vfs_write(p, buf, count, &p->f_pos);
1189 return tty_write(file, buf, count, ppos);
1192 static char ptychar[] = "pqrstuvwxyzabcde";
1195 * pty_line_name - generate name for a pty
1196 * @driver: the tty driver in use
1197 * @index: the minor number
1198 * @p: output buffer of at least 6 bytes
1200 * Generate a name from a driver reference and write it to the output
1205 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1207 int i = index + driver->name_base;
1208 /* ->name is initialized to "ttyp", but "tty" is expected */
1209 sprintf(p, "%s%c%x",
1210 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1211 ptychar[i >> 4 & 0xf], i & 0xf);
1215 * tty_line_name - generate name for a tty
1216 * @driver: the tty driver in use
1217 * @index: the minor number
1218 * @p: output buffer of at least 7 bytes
1220 * Generate a name from a driver reference and write it to the output
1225 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1227 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1228 strcpy(p, driver->name);
1230 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1234 * tty_driver_lookup_tty() - find an existing tty, if any
1235 * @driver: the driver for the tty
1236 * @idx: the minor number
1238 * Return the tty, if found or ERR_PTR() otherwise.
1240 * Locking: tty_mutex must be held. If tty is found, the mutex must
1241 * be held until the 'fast-open' is also done. Will change once we
1242 * have refcounting in the driver and per driver locking
1244 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1245 struct inode *inode, int idx)
1247 if (driver->ops->lookup)
1248 return driver->ops->lookup(driver, inode, idx);
1250 return driver->ttys[idx];
1254 * tty_init_termios - helper for termios setup
1255 * @tty: the tty to set up
1257 * Initialise the termios structures for this tty. Thus runs under
1258 * the tty_mutex currently so we can be relaxed about ordering.
1261 int tty_init_termios(struct tty_struct *tty)
1263 struct ktermios *tp;
1264 int idx = tty->index;
1266 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1267 tty->termios = tty->driver->init_termios;
1269 /* Check for lazy saved data */
1270 tp = tty->driver->termios[idx];
1274 tty->termios = tty->driver->init_termios;
1276 /* Compatibility until drivers always set this */
1277 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1278 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1281 EXPORT_SYMBOL_GPL(tty_init_termios);
1283 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1285 int ret = tty_init_termios(tty);
1289 tty_driver_kref_get(driver);
1291 driver->ttys[tty->index] = tty;
1294 EXPORT_SYMBOL_GPL(tty_standard_install);
1297 * tty_driver_install_tty() - install a tty entry in the driver
1298 * @driver: the driver for the tty
1301 * Install a tty object into the driver tables. The tty->index field
1302 * will be set by the time this is called. This method is responsible
1303 * for ensuring any need additional structures are allocated and
1306 * Locking: tty_mutex for now
1308 static int tty_driver_install_tty(struct tty_driver *driver,
1309 struct tty_struct *tty)
1311 return driver->ops->install ? driver->ops->install(driver, tty) :
1312 tty_standard_install(driver, tty);
1316 * tty_driver_remove_tty() - remove a tty from the driver tables
1317 * @driver: the driver for the tty
1318 * @idx: the minor number
1320 * Remvoe a tty object from the driver tables. The tty->index field
1321 * will be set by the time this is called.
1323 * Locking: tty_mutex for now
1325 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1327 if (driver->ops->remove)
1328 driver->ops->remove(driver, tty);
1330 driver->ttys[tty->index] = NULL;
1334 * tty_reopen() - fast re-open of an open tty
1335 * @tty - the tty to open
1337 * Return 0 on success, -errno on error.
1339 * Locking: tty_mutex must be held from the time the tty was found
1340 * till this open completes.
1342 static int tty_reopen(struct tty_struct *tty)
1344 struct tty_driver *driver = tty->driver;
1346 if (test_bit(TTY_CLOSING, &tty->flags) ||
1347 test_bit(TTY_HUPPING, &tty->flags) ||
1348 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1351 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1352 driver->subtype == PTY_TYPE_MASTER) {
1354 * special case for PTY masters: only one open permitted,
1355 * and the slave side open count is incremented as well.
1364 mutex_lock(&tty->ldisc_mutex);
1365 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1366 mutex_unlock(&tty->ldisc_mutex);
1372 * tty_init_dev - initialise a tty device
1373 * @driver: tty driver we are opening a device on
1374 * @idx: device index
1375 * @ret_tty: returned tty structure
1377 * Prepare a tty device. This may not be a "new" clean device but
1378 * could also be an active device. The pty drivers require special
1379 * handling because of this.
1382 * The function is called under the tty_mutex, which
1383 * protects us from the tty struct or driver itself going away.
1385 * On exit the tty device has the line discipline attached and
1386 * a reference count of 1. If a pair was created for pty/tty use
1387 * and the other was a pty master then it too has a reference count of 1.
1389 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1390 * failed open. The new code protects the open with a mutex, so it's
1391 * really quite straightforward. The mutex locking can probably be
1392 * relaxed for the (most common) case of reopening a tty.
1395 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1397 struct tty_struct *tty;
1401 * First time open is complex, especially for PTY devices.
1402 * This code guarantees that either everything succeeds and the
1403 * TTY is ready for operation, or else the table slots are vacated
1404 * and the allocated memory released. (Except that the termios
1405 * and locked termios may be retained.)
1408 if (!try_module_get(driver->owner))
1409 return ERR_PTR(-ENODEV);
1411 tty = alloc_tty_struct();
1414 goto err_module_put;
1416 initialize_tty_struct(tty, driver, idx);
1419 retval = tty_driver_install_tty(driver, tty);
1421 goto err_deinit_tty;
1424 tty->port = driver->ports[idx];
1426 WARN_RATELIMIT(!tty->port,
1427 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1428 __func__, tty->driver->name);
1430 tty->port->itty = tty;
1433 * Structures all installed ... call the ldisc open routines.
1434 * If we fail here just call release_tty to clean up. No need
1435 * to decrement the use counts, as release_tty doesn't care.
1437 retval = tty_ldisc_setup(tty, tty->link);
1439 goto err_release_tty;
1440 /* Return the tty locked so that it cannot vanish under the caller */
1445 deinitialize_tty_struct(tty);
1446 free_tty_struct(tty);
1448 module_put(driver->owner);
1449 return ERR_PTR(retval);
1451 /* call the tty release_tty routine to clean out this slot */
1454 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1455 "clearing slot %d\n", idx);
1456 release_tty(tty, idx);
1457 return ERR_PTR(retval);
1460 void tty_free_termios(struct tty_struct *tty)
1462 struct ktermios *tp;
1463 int idx = tty->index;
1465 /* If the port is going to reset then it has no termios to save */
1466 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1469 /* Stash the termios data */
1470 tp = tty->driver->termios[idx];
1472 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1474 pr_warn("tty: no memory to save termios state.\n");
1477 tty->driver->termios[idx] = tp;
1481 EXPORT_SYMBOL(tty_free_termios);
1485 * release_one_tty - release tty structure memory
1486 * @kref: kref of tty we are obliterating
1488 * Releases memory associated with a tty structure, and clears out the
1489 * driver table slots. This function is called when a device is no longer
1490 * in use. It also gets called when setup of a device fails.
1493 * takes the file list lock internally when working on the list
1494 * of ttys that the driver keeps.
1496 * This method gets called from a work queue so that the driver private
1497 * cleanup ops can sleep (needed for USB at least)
1499 static void release_one_tty(struct work_struct *work)
1501 struct tty_struct *tty =
1502 container_of(work, struct tty_struct, hangup_work);
1503 struct tty_driver *driver = tty->driver;
1505 if (tty->ops->cleanup)
1506 tty->ops->cleanup(tty);
1509 tty_driver_kref_put(driver);
1510 module_put(driver->owner);
1512 spin_lock(&tty_files_lock);
1513 list_del_init(&tty->tty_files);
1514 spin_unlock(&tty_files_lock);
1517 put_pid(tty->session);
1518 free_tty_struct(tty);
1521 static void queue_release_one_tty(struct kref *kref)
1523 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1525 /* The hangup queue is now free so we can reuse it rather than
1526 waste a chunk of memory for each port */
1527 INIT_WORK(&tty->hangup_work, release_one_tty);
1528 schedule_work(&tty->hangup_work);
1532 * tty_kref_put - release a tty kref
1535 * Release a reference to a tty device and if need be let the kref
1536 * layer destruct the object for us
1539 void tty_kref_put(struct tty_struct *tty)
1542 kref_put(&tty->kref, queue_release_one_tty);
1544 EXPORT_SYMBOL(tty_kref_put);
1547 * release_tty - release tty structure memory
1549 * Release both @tty and a possible linked partner (think pty pair),
1550 * and decrement the refcount of the backing module.
1554 * takes the file list lock internally when working on the list
1555 * of ttys that the driver keeps.
1558 static void release_tty(struct tty_struct *tty, int idx)
1560 /* This should always be true but check for the moment */
1561 WARN_ON(tty->index != idx);
1562 WARN_ON(!mutex_is_locked(&tty_mutex));
1563 if (tty->ops->shutdown)
1564 tty->ops->shutdown(tty);
1565 tty_free_termios(tty);
1566 tty_driver_remove_tty(tty->driver, tty);
1567 tty->port->itty = NULL;
1570 tty_kref_put(tty->link);
1575 * tty_release_checks - check a tty before real release
1576 * @tty: tty to check
1577 * @o_tty: link of @tty (if any)
1578 * @idx: index of the tty
1580 * Performs some paranoid checking before true release of the @tty.
1581 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1583 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1586 #ifdef TTY_PARANOIA_CHECK
1587 if (idx < 0 || idx >= tty->driver->num) {
1588 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1589 __func__, tty->name);
1593 /* not much to check for devpts */
1594 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1597 if (tty != tty->driver->ttys[idx]) {
1598 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1599 __func__, idx, tty->name);
1602 if (tty->driver->other) {
1603 if (o_tty != tty->driver->other->ttys[idx]) {
1604 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1605 __func__, idx, tty->name);
1608 if (o_tty->link != tty) {
1609 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1618 * tty_release - vfs callback for close
1619 * @inode: inode of tty
1620 * @filp: file pointer for handle to tty
1622 * Called the last time each file handle is closed that references
1623 * this tty. There may however be several such references.
1626 * Takes bkl. See tty_release_dev
1628 * Even releasing the tty structures is a tricky business.. We have
1629 * to be very careful that the structures are all released at the
1630 * same time, as interrupts might otherwise get the wrong pointers.
1632 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1633 * lead to double frees or releasing memory still in use.
1636 int tty_release(struct inode *inode, struct file *filp)
1638 struct tty_struct *tty = file_tty(filp);
1639 struct tty_struct *o_tty;
1640 int pty_master, tty_closing, o_tty_closing, do_sleep;
1644 if (tty_paranoia_check(tty, inode, __func__))
1648 check_tty_count(tty, __func__);
1650 __tty_fasync(-1, filp, 0);
1653 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1654 tty->driver->subtype == PTY_TYPE_MASTER);
1655 /* Review: parallel close */
1658 if (tty_release_checks(tty, o_tty, idx)) {
1663 #ifdef TTY_DEBUG_HANGUP
1664 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1665 tty_name(tty, buf), tty->count);
1668 if (tty->ops->close)
1669 tty->ops->close(tty, filp);
1673 * Sanity check: if tty->count is going to zero, there shouldn't be
1674 * any waiters on tty->read_wait or tty->write_wait. We test the
1675 * wait queues and kick everyone out _before_ actually starting to
1676 * close. This ensures that we won't block while releasing the tty
1679 * The test for the o_tty closing is necessary, since the master and
1680 * slave sides may close in any order. If the slave side closes out
1681 * first, its count will be one, since the master side holds an open.
1682 * Thus this test wouldn't be triggered at the time the slave closes,
1685 * Note that it's possible for the tty to be opened again while we're
1686 * flushing out waiters. By recalculating the closing flags before
1687 * each iteration we avoid any problems.
1690 /* Guard against races with tty->count changes elsewhere and
1691 opens on /dev/tty */
1693 mutex_lock(&tty_mutex);
1694 tty_lock_pair(tty, o_tty);
1695 tty_closing = tty->count <= 1;
1696 o_tty_closing = o_tty &&
1697 (o_tty->count <= (pty_master ? 1 : 0));
1701 if (waitqueue_active(&tty->read_wait)) {
1702 wake_up_poll(&tty->read_wait, POLLIN);
1705 if (waitqueue_active(&tty->write_wait)) {
1706 wake_up_poll(&tty->write_wait, POLLOUT);
1710 if (o_tty_closing) {
1711 if (waitqueue_active(&o_tty->read_wait)) {
1712 wake_up_poll(&o_tty->read_wait, POLLIN);
1715 if (waitqueue_active(&o_tty->write_wait)) {
1716 wake_up_poll(&o_tty->write_wait, POLLOUT);
1723 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1724 __func__, tty_name(tty, buf));
1725 tty_unlock_pair(tty, o_tty);
1726 mutex_unlock(&tty_mutex);
1731 * The closing flags are now consistent with the open counts on
1732 * both sides, and we've completed the last operation that could
1733 * block, so it's safe to proceed with closing.
1735 * We must *not* drop the tty_mutex until we ensure that a further
1736 * entry into tty_open can not pick up this tty.
1739 if (--o_tty->count < 0) {
1740 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1741 __func__, o_tty->count, tty_name(o_tty, buf));
1745 if (--tty->count < 0) {
1746 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1747 __func__, tty->count, tty_name(tty, buf));
1752 * We've decremented tty->count, so we need to remove this file
1753 * descriptor off the tty->tty_files list; this serves two
1755 * - check_tty_count sees the correct number of file descriptors
1756 * associated with this tty.
1757 * - do_tty_hangup no longer sees this file descriptor as
1758 * something that needs to be handled for hangups.
1763 * Perform some housekeeping before deciding whether to return.
1765 * Set the TTY_CLOSING flag if this was the last open. In the
1766 * case of a pty we may have to wait around for the other side
1767 * to close, and TTY_CLOSING makes sure we can't be reopened.
1770 set_bit(TTY_CLOSING, &tty->flags);
1772 set_bit(TTY_CLOSING, &o_tty->flags);
1775 * If _either_ side is closing, make sure there aren't any
1776 * processes that still think tty or o_tty is their controlling
1779 if (tty_closing || o_tty_closing) {
1780 read_lock(&tasklist_lock);
1781 session_clear_tty(tty->session);
1783 session_clear_tty(o_tty->session);
1784 read_unlock(&tasklist_lock);
1787 mutex_unlock(&tty_mutex);
1788 tty_unlock_pair(tty, o_tty);
1789 /* At this point the TTY_CLOSING flag should ensure a dead tty
1790 cannot be re-opened by a racing opener */
1792 /* check whether both sides are closing ... */
1793 if (!tty_closing || (o_tty && !o_tty_closing))
1796 #ifdef TTY_DEBUG_HANGUP
1797 printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__);
1800 * Ask the line discipline code to release its structures
1802 tty_ldisc_release(tty, o_tty);
1804 * The release_tty function takes care of the details of clearing
1805 * the slots and preserving the termios structure. The tty_unlock_pair
1806 * should be safe as we keep a kref while the tty is locked (so the
1807 * unlock never unlocks a freed tty).
1809 mutex_lock(&tty_mutex);
1810 release_tty(tty, idx);
1811 mutex_unlock(&tty_mutex);
1817 * tty_open_current_tty - get tty of current task for open
1818 * @device: device number
1819 * @filp: file pointer to tty
1820 * @return: tty of the current task iff @device is /dev/tty
1822 * We cannot return driver and index like for the other nodes because
1823 * devpts will not work then. It expects inodes to be from devpts FS.
1825 * We need to move to returning a refcounted object from all the lookup
1826 * paths including this one.
1828 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1830 struct tty_struct *tty;
1832 if (device != MKDEV(TTYAUX_MAJOR, 0))
1835 tty = get_current_tty();
1837 return ERR_PTR(-ENXIO);
1839 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1842 /* FIXME: we put a reference and return a TTY! */
1843 /* This is only safe because the caller holds tty_mutex */
1848 * tty_lookup_driver - lookup a tty driver for a given device file
1849 * @device: device number
1850 * @filp: file pointer to tty
1851 * @noctty: set if the device should not become a controlling tty
1852 * @index: index for the device in the @return driver
1853 * @return: driver for this inode (with increased refcount)
1855 * If @return is not erroneous, the caller is responsible to decrement the
1856 * refcount by tty_driver_kref_put.
1858 * Locking: tty_mutex protects get_tty_driver
1860 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1861 int *noctty, int *index)
1863 struct tty_driver *driver;
1867 case MKDEV(TTY_MAJOR, 0): {
1868 extern struct tty_driver *console_driver;
1869 driver = tty_driver_kref_get(console_driver);
1870 *index = fg_console;
1875 case MKDEV(TTYAUX_MAJOR, 1): {
1876 struct tty_driver *console_driver = console_device(index);
1877 if (console_driver) {
1878 driver = tty_driver_kref_get(console_driver);
1880 /* Don't let /dev/console block */
1881 filp->f_flags |= O_NONBLOCK;
1886 return ERR_PTR(-ENODEV);
1889 driver = get_tty_driver(device, index);
1891 return ERR_PTR(-ENODEV);
1898 * tty_open - open a tty device
1899 * @inode: inode of device file
1900 * @filp: file pointer to tty
1902 * tty_open and tty_release keep up the tty count that contains the
1903 * number of opens done on a tty. We cannot use the inode-count, as
1904 * different inodes might point to the same tty.
1906 * Open-counting is needed for pty masters, as well as for keeping
1907 * track of serial lines: DTR is dropped when the last close happens.
1908 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1910 * The termios state of a pty is reset on first open so that
1911 * settings don't persist across reuse.
1913 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1914 * tty->count should protect the rest.
1915 * ->siglock protects ->signal/->sighand
1917 * Note: the tty_unlock/lock cases without a ref are only safe due to
1921 static int tty_open(struct inode *inode, struct file *filp)
1923 struct tty_struct *tty;
1925 struct tty_driver *driver = NULL;
1927 dev_t device = inode->i_rdev;
1928 unsigned saved_flags = filp->f_flags;
1930 nonseekable_open(inode, filp);
1933 retval = tty_alloc_file(filp);
1937 noctty = filp->f_flags & O_NOCTTY;
1941 mutex_lock(&tty_mutex);
1942 /* This is protected by the tty_mutex */
1943 tty = tty_open_current_tty(device, filp);
1945 retval = PTR_ERR(tty);
1948 driver = tty_lookup_driver(device, filp, &noctty, &index);
1949 if (IS_ERR(driver)) {
1950 retval = PTR_ERR(driver);
1954 /* check whether we're reopening an existing tty */
1955 tty = tty_driver_lookup_tty(driver, inode, index);
1957 retval = PTR_ERR(tty);
1964 retval = tty_reopen(tty);
1967 tty = ERR_PTR(retval);
1969 } else /* Returns with the tty_lock held for now */
1970 tty = tty_init_dev(driver, index);
1972 mutex_unlock(&tty_mutex);
1974 tty_driver_kref_put(driver);
1976 retval = PTR_ERR(tty);
1980 tty_add_file(tty, filp);
1982 check_tty_count(tty, __func__);
1983 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1984 tty->driver->subtype == PTY_TYPE_MASTER)
1986 #ifdef TTY_DEBUG_HANGUP
1987 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
1990 retval = tty->ops->open(tty, filp);
1993 filp->f_flags = saved_flags;
1995 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1996 !capable(CAP_SYS_ADMIN))
2000 #ifdef TTY_DEBUG_HANGUP
2001 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
2004 tty_unlock(tty); /* need to call tty_release without BTM */
2005 tty_release(inode, filp);
2006 if (retval != -ERESTARTSYS)
2009 if (signal_pending(current))
2014 * Need to reset f_op in case a hangup happened.
2016 if (filp->f_op == &hung_up_tty_fops)
2017 filp->f_op = &tty_fops;
2023 mutex_lock(&tty_mutex);
2025 spin_lock_irq(¤t->sighand->siglock);
2027 current->signal->leader &&
2028 !current->signal->tty &&
2029 tty->session == NULL)
2030 __proc_set_tty(current, tty);
2031 spin_unlock_irq(¤t->sighand->siglock);
2033 mutex_unlock(&tty_mutex);
2036 mutex_unlock(&tty_mutex);
2037 /* after locks to avoid deadlock */
2038 if (!IS_ERR_OR_NULL(driver))
2039 tty_driver_kref_put(driver);
2041 tty_free_file(filp);
2048 * tty_poll - check tty status
2049 * @filp: file being polled
2050 * @wait: poll wait structures to update
2052 * Call the line discipline polling method to obtain the poll
2053 * status of the device.
2055 * Locking: locks called line discipline but ldisc poll method
2056 * may be re-entered freely by other callers.
2059 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2061 struct tty_struct *tty = file_tty(filp);
2062 struct tty_ldisc *ld;
2065 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2068 ld = tty_ldisc_ref_wait(tty);
2070 ret = (ld->ops->poll)(tty, filp, wait);
2071 tty_ldisc_deref(ld);
2075 static int __tty_fasync(int fd, struct file *filp, int on)
2077 struct tty_struct *tty = file_tty(filp);
2078 unsigned long flags;
2081 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2084 retval = fasync_helper(fd, filp, on, &tty->fasync);
2091 if (!waitqueue_active(&tty->read_wait))
2092 tty->minimum_to_wake = 1;
2093 spin_lock_irqsave(&tty->ctrl_lock, flags);
2096 type = PIDTYPE_PGID;
2098 pid = task_pid(current);
2102 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2103 retval = __f_setown(filp, pid, type, 0);
2108 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2109 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2116 static int tty_fasync(int fd, struct file *filp, int on)
2118 struct tty_struct *tty = file_tty(filp);
2122 retval = __tty_fasync(fd, filp, on);
2129 * tiocsti - fake input character
2130 * @tty: tty to fake input into
2131 * @p: pointer to character
2133 * Fake input to a tty device. Does the necessary locking and
2136 * FIXME: does not honour flow control ??
2139 * Called functions take tty_ldisc_lock
2140 * current->signal->tty check is safe without locks
2142 * FIXME: may race normal receive processing
2145 static int tiocsti(struct tty_struct *tty, char __user *p)
2148 struct tty_ldisc *ld;
2150 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2152 if (get_user(ch, p))
2154 tty_audit_tiocsti(tty, ch);
2155 ld = tty_ldisc_ref_wait(tty);
2156 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2157 tty_ldisc_deref(ld);
2162 * tiocgwinsz - implement window query ioctl
2164 * @arg: user buffer for result
2166 * Copies the kernel idea of the window size into the user buffer.
2168 * Locking: tty->termios_mutex is taken to ensure the winsize data
2172 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2176 mutex_lock(&tty->termios_mutex);
2177 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2178 mutex_unlock(&tty->termios_mutex);
2180 return err ? -EFAULT: 0;
2184 * tty_do_resize - resize event
2185 * @tty: tty being resized
2186 * @rows: rows (character)
2187 * @cols: cols (character)
2189 * Update the termios variables and send the necessary signals to
2190 * peform a terminal resize correctly
2193 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2196 unsigned long flags;
2199 mutex_lock(&tty->termios_mutex);
2200 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2202 /* Get the PID values and reference them so we can
2203 avoid holding the tty ctrl lock while sending signals */
2204 spin_lock_irqsave(&tty->ctrl_lock, flags);
2205 pgrp = get_pid(tty->pgrp);
2206 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2209 kill_pgrp(pgrp, SIGWINCH, 1);
2214 mutex_unlock(&tty->termios_mutex);
2217 EXPORT_SYMBOL(tty_do_resize);
2220 * tiocswinsz - implement window size set ioctl
2221 * @tty; tty side of tty
2222 * @arg: user buffer for result
2224 * Copies the user idea of the window size to the kernel. Traditionally
2225 * this is just advisory information but for the Linux console it
2226 * actually has driver level meaning and triggers a VC resize.
2229 * Driver dependent. The default do_resize method takes the
2230 * tty termios mutex and ctrl_lock. The console takes its own lock
2231 * then calls into the default method.
2234 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2236 struct winsize tmp_ws;
2237 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2240 if (tty->ops->resize)
2241 return tty->ops->resize(tty, &tmp_ws);
2243 return tty_do_resize(tty, &tmp_ws);
2247 * tioccons - allow admin to move logical console
2248 * @file: the file to become console
2250 * Allow the administrator to move the redirected console device
2252 * Locking: uses redirect_lock to guard the redirect information
2255 static int tioccons(struct file *file)
2257 if (!capable(CAP_SYS_ADMIN))
2259 if (file->f_op->write == redirected_tty_write) {
2261 spin_lock(&redirect_lock);
2264 spin_unlock(&redirect_lock);
2269 spin_lock(&redirect_lock);
2271 spin_unlock(&redirect_lock);
2274 redirect = get_file(file);
2275 spin_unlock(&redirect_lock);
2280 * fionbio - non blocking ioctl
2281 * @file: file to set blocking value
2282 * @p: user parameter
2284 * Historical tty interfaces had a blocking control ioctl before
2285 * the generic functionality existed. This piece of history is preserved
2286 * in the expected tty API of posix OS's.
2288 * Locking: none, the open file handle ensures it won't go away.
2291 static int fionbio(struct file *file, int __user *p)
2295 if (get_user(nonblock, p))
2298 spin_lock(&file->f_lock);
2300 file->f_flags |= O_NONBLOCK;
2302 file->f_flags &= ~O_NONBLOCK;
2303 spin_unlock(&file->f_lock);
2308 * tiocsctty - set controlling tty
2309 * @tty: tty structure
2310 * @arg: user argument
2312 * This ioctl is used to manage job control. It permits a session
2313 * leader to set this tty as the controlling tty for the session.
2316 * Takes tty_mutex() to protect tty instance
2317 * Takes tasklist_lock internally to walk sessions
2318 * Takes ->siglock() when updating signal->tty
2321 static int tiocsctty(struct tty_struct *tty, int arg)
2324 if (current->signal->leader && (task_session(current) == tty->session))
2327 mutex_lock(&tty_mutex);
2329 * The process must be a session leader and
2330 * not have a controlling tty already.
2332 if (!current->signal->leader || current->signal->tty) {
2339 * This tty is already the controlling
2340 * tty for another session group!
2342 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2346 read_lock(&tasklist_lock);
2347 session_clear_tty(tty->session);
2348 read_unlock(&tasklist_lock);
2354 proc_set_tty(current, tty);
2356 mutex_unlock(&tty_mutex);
2361 * tty_get_pgrp - return a ref counted pgrp pid
2364 * Returns a refcounted instance of the pid struct for the process
2365 * group controlling the tty.
2368 struct pid *tty_get_pgrp(struct tty_struct *tty)
2370 unsigned long flags;
2373 spin_lock_irqsave(&tty->ctrl_lock, flags);
2374 pgrp = get_pid(tty->pgrp);
2375 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2379 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2382 * tiocgpgrp - get process group
2383 * @tty: tty passed by user
2384 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2387 * Obtain the process group of the tty. If there is no process group
2390 * Locking: none. Reference to current->signal->tty is safe.
2393 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2398 * (tty == real_tty) is a cheap way of
2399 * testing if the tty is NOT a master pty.
2401 if (tty == real_tty && current->signal->tty != real_tty)
2403 pid = tty_get_pgrp(real_tty);
2404 ret = put_user(pid_vnr(pid), p);
2410 * tiocspgrp - attempt to set process group
2411 * @tty: tty passed by user
2412 * @real_tty: tty side device matching tty passed by user
2415 * Set the process group of the tty to the session passed. Only
2416 * permitted where the tty session is our session.
2418 * Locking: RCU, ctrl lock
2421 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2425 int retval = tty_check_change(real_tty);
2426 unsigned long flags;
2432 if (!current->signal->tty ||
2433 (current->signal->tty != real_tty) ||
2434 (real_tty->session != task_session(current)))
2436 if (get_user(pgrp_nr, p))
2441 pgrp = find_vpid(pgrp_nr);
2446 if (session_of_pgrp(pgrp) != task_session(current))
2449 spin_lock_irqsave(&tty->ctrl_lock, flags);
2450 put_pid(real_tty->pgrp);
2451 real_tty->pgrp = get_pid(pgrp);
2452 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2459 * tiocgsid - get session id
2460 * @tty: tty passed by user
2461 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2462 * @p: pointer to returned session id
2464 * Obtain the session id of the tty. If there is no session
2467 * Locking: none. Reference to current->signal->tty is safe.
2470 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2473 * (tty == real_tty) is a cheap way of
2474 * testing if the tty is NOT a master pty.
2476 if (tty == real_tty && current->signal->tty != real_tty)
2478 if (!real_tty->session)
2480 return put_user(pid_vnr(real_tty->session), p);
2484 * tiocsetd - set line discipline
2486 * @p: pointer to user data
2488 * Set the line discipline according to user request.
2490 * Locking: see tty_set_ldisc, this function is just a helper
2493 static int tiocsetd(struct tty_struct *tty, int __user *p)
2498 if (get_user(ldisc, p))
2501 ret = tty_set_ldisc(tty, ldisc);
2507 * send_break - performed time break
2508 * @tty: device to break on
2509 * @duration: timeout in mS
2511 * Perform a timed break on hardware that lacks its own driver level
2512 * timed break functionality.
2515 * atomic_write_lock serializes
2519 static int send_break(struct tty_struct *tty, unsigned int duration)
2523 if (tty->ops->break_ctl == NULL)
2526 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2527 retval = tty->ops->break_ctl(tty, duration);
2529 /* Do the work ourselves */
2530 if (tty_write_lock(tty, 0) < 0)
2532 retval = tty->ops->break_ctl(tty, -1);
2535 if (!signal_pending(current))
2536 msleep_interruptible(duration);
2537 retval = tty->ops->break_ctl(tty, 0);
2539 tty_write_unlock(tty);
2540 if (signal_pending(current))
2547 * tty_tiocmget - get modem status
2549 * @file: user file pointer
2550 * @p: pointer to result
2552 * Obtain the modem status bits from the tty driver if the feature
2553 * is supported. Return -EINVAL if it is not available.
2555 * Locking: none (up to the driver)
2558 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2560 int retval = -EINVAL;
2562 if (tty->ops->tiocmget) {
2563 retval = tty->ops->tiocmget(tty);
2566 retval = put_user(retval, p);
2572 * tty_tiocmset - set modem status
2574 * @cmd: command - clear bits, set bits or set all
2575 * @p: pointer to desired bits
2577 * Set the modem status bits from the tty driver if the feature
2578 * is supported. Return -EINVAL if it is not available.
2580 * Locking: none (up to the driver)
2583 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2587 unsigned int set, clear, val;
2589 if (tty->ops->tiocmset == NULL)
2592 retval = get_user(val, p);
2608 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2609 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2610 return tty->ops->tiocmset(tty, set, clear);
2613 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2615 int retval = -EINVAL;
2616 struct serial_icounter_struct icount;
2617 memset(&icount, 0, sizeof(icount));
2618 if (tty->ops->get_icount)
2619 retval = tty->ops->get_icount(tty, &icount);
2622 if (copy_to_user(arg, &icount, sizeof(icount)))
2627 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2629 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2630 tty->driver->subtype == PTY_TYPE_MASTER)
2634 EXPORT_SYMBOL(tty_pair_get_tty);
2636 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2638 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2639 tty->driver->subtype == PTY_TYPE_MASTER)
2643 EXPORT_SYMBOL(tty_pair_get_pty);
2646 * Split this up, as gcc can choke on it otherwise..
2648 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2650 struct tty_struct *tty = file_tty(file);
2651 struct tty_struct *real_tty;
2652 void __user *p = (void __user *)arg;
2654 struct tty_ldisc *ld;
2656 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2659 real_tty = tty_pair_get_tty(tty);
2662 * Factor out some common prep work
2670 retval = tty_check_change(tty);
2673 if (cmd != TIOCCBRK) {
2674 tty_wait_until_sent(tty, 0);
2675 if (signal_pending(current))
2686 return tiocsti(tty, p);
2688 return tiocgwinsz(real_tty, p);
2690 return tiocswinsz(real_tty, p);
2692 return real_tty != tty ? -EINVAL : tioccons(file);
2694 return fionbio(file, p);
2696 set_bit(TTY_EXCLUSIVE, &tty->flags);
2699 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2703 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2704 return put_user(excl, (int __user *)p);
2707 if (current->signal->tty != tty)
2712 return tiocsctty(tty, arg);
2714 return tiocgpgrp(tty, real_tty, p);
2716 return tiocspgrp(tty, real_tty, p);
2718 return tiocgsid(tty, real_tty, p);
2720 return put_user(tty->ldisc->ops->num, (int __user *)p);
2722 return tiocsetd(tty, p);
2724 if (!capable(CAP_SYS_ADMIN))
2730 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2731 return put_user(ret, (unsigned int __user *)p);
2736 case TIOCSBRK: /* Turn break on, unconditionally */
2737 if (tty->ops->break_ctl)
2738 return tty->ops->break_ctl(tty, -1);
2740 case TIOCCBRK: /* Turn break off, unconditionally */
2741 if (tty->ops->break_ctl)
2742 return tty->ops->break_ctl(tty, 0);
2744 case TCSBRK: /* SVID version: non-zero arg --> no break */
2745 /* non-zero arg means wait for all output data
2746 * to be sent (performed above) but don't send break.
2747 * This is used by the tcdrain() termios function.
2750 return send_break(tty, 250);
2752 case TCSBRKP: /* support for POSIX tcsendbreak() */
2753 return send_break(tty, arg ? arg*100 : 250);
2756 return tty_tiocmget(tty, p);
2760 return tty_tiocmset(tty, cmd, p);
2762 retval = tty_tiocgicount(tty, p);
2763 /* For the moment allow fall through to the old method */
2764 if (retval != -EINVAL)
2771 /* flush tty buffer and allow ldisc to process ioctl */
2772 tty_buffer_flush(tty);
2777 if (tty->ops->ioctl) {
2778 retval = (tty->ops->ioctl)(tty, cmd, arg);
2779 if (retval != -ENOIOCTLCMD)
2782 ld = tty_ldisc_ref_wait(tty);
2784 if (ld->ops->ioctl) {
2785 retval = ld->ops->ioctl(tty, file, cmd, arg);
2786 if (retval == -ENOIOCTLCMD)
2789 tty_ldisc_deref(ld);
2793 #ifdef CONFIG_COMPAT
2794 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2797 struct tty_struct *tty = file_tty(file);
2798 struct tty_ldisc *ld;
2799 int retval = -ENOIOCTLCMD;
2801 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2804 if (tty->ops->compat_ioctl) {
2805 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2806 if (retval != -ENOIOCTLCMD)
2810 ld = tty_ldisc_ref_wait(tty);
2811 if (ld->ops->compat_ioctl)
2812 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2814 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2815 tty_ldisc_deref(ld);
2821 static int this_tty(const void *t, struct file *file, unsigned fd)
2823 if (likely(file->f_op->read != tty_read))
2825 return file_tty(file) != t ? 0 : fd + 1;
2829 * This implements the "Secure Attention Key" --- the idea is to
2830 * prevent trojan horses by killing all processes associated with this
2831 * tty when the user hits the "Secure Attention Key". Required for
2832 * super-paranoid applications --- see the Orange Book for more details.
2834 * This code could be nicer; ideally it should send a HUP, wait a few
2835 * seconds, then send a INT, and then a KILL signal. But you then
2836 * have to coordinate with the init process, since all processes associated
2837 * with the current tty must be dead before the new getty is allowed
2840 * Now, if it would be correct ;-/ The current code has a nasty hole -
2841 * it doesn't catch files in flight. We may send the descriptor to ourselves
2842 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2844 * Nasty bug: do_SAK is being called in interrupt context. This can
2845 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2847 void __do_SAK(struct tty_struct *tty)
2852 struct task_struct *g, *p;
2853 struct pid *session;
2858 session = tty->session;
2860 tty_ldisc_flush(tty);
2862 tty_driver_flush_buffer(tty);
2864 read_lock(&tasklist_lock);
2865 /* Kill the entire session */
2866 do_each_pid_task(session, PIDTYPE_SID, p) {
2867 printk(KERN_NOTICE "SAK: killed process %d"
2868 " (%s): task_session(p)==tty->session\n",
2869 task_pid_nr(p), p->comm);
2870 send_sig(SIGKILL, p, 1);
2871 } while_each_pid_task(session, PIDTYPE_SID, p);
2872 /* Now kill any processes that happen to have the
2875 do_each_thread(g, p) {
2876 if (p->signal->tty == tty) {
2877 printk(KERN_NOTICE "SAK: killed process %d"
2878 " (%s): task_session(p)==tty->session\n",
2879 task_pid_nr(p), p->comm);
2880 send_sig(SIGKILL, p, 1);
2884 i = iterate_fd(p->files, 0, this_tty, tty);
2886 printk(KERN_NOTICE "SAK: killed process %d"
2887 " (%s): fd#%d opened to the tty\n",
2888 task_pid_nr(p), p->comm, i - 1);
2889 force_sig(SIGKILL, p);
2892 } while_each_thread(g, p);
2893 read_unlock(&tasklist_lock);
2897 static void do_SAK_work(struct work_struct *work)
2899 struct tty_struct *tty =
2900 container_of(work, struct tty_struct, SAK_work);
2905 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2906 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2907 * the values which we write to it will be identical to the values which it
2908 * already has. --akpm
2910 void do_SAK(struct tty_struct *tty)
2914 schedule_work(&tty->SAK_work);
2917 EXPORT_SYMBOL(do_SAK);
2919 static int dev_match_devt(struct device *dev, const void *data)
2921 const dev_t *devt = data;
2922 return dev->devt == *devt;
2925 /* Must put_device() after it's unused! */
2926 static struct device *tty_get_device(struct tty_struct *tty)
2928 dev_t devt = tty_devnum(tty);
2929 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2934 * initialize_tty_struct
2935 * @tty: tty to initialize
2937 * This subroutine initializes a tty structure that has been newly
2940 * Locking: none - tty in question must not be exposed at this point
2943 void initialize_tty_struct(struct tty_struct *tty,
2944 struct tty_driver *driver, int idx)
2946 memset(tty, 0, sizeof(struct tty_struct));
2947 kref_init(&tty->kref);
2948 tty->magic = TTY_MAGIC;
2949 tty_ldisc_init(tty);
2950 tty->session = NULL;
2952 mutex_init(&tty->legacy_mutex);
2953 mutex_init(&tty->termios_mutex);
2954 mutex_init(&tty->ldisc_mutex);
2955 init_waitqueue_head(&tty->write_wait);
2956 init_waitqueue_head(&tty->read_wait);
2957 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2958 mutex_init(&tty->atomic_write_lock);
2959 spin_lock_init(&tty->ctrl_lock);
2960 INIT_LIST_HEAD(&tty->tty_files);
2961 INIT_WORK(&tty->SAK_work, do_SAK_work);
2963 tty->driver = driver;
2964 tty->ops = driver->ops;
2966 tty_line_name(driver, idx, tty->name);
2967 tty->dev = tty_get_device(tty);
2971 * deinitialize_tty_struct
2972 * @tty: tty to deinitialize
2974 * This subroutine deinitializes a tty structure that has been newly
2975 * allocated but tty_release cannot be called on that yet.
2977 * Locking: none - tty in question must not be exposed at this point
2979 void deinitialize_tty_struct(struct tty_struct *tty)
2981 tty_ldisc_deinit(tty);
2985 * tty_put_char - write one character to a tty
2989 * Write one byte to the tty using the provided put_char method
2990 * if present. Returns the number of characters successfully output.
2992 * Note: the specific put_char operation in the driver layer may go
2993 * away soon. Don't call it directly, use this method
2996 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2998 if (tty->ops->put_char)
2999 return tty->ops->put_char(tty, ch);
3000 return tty->ops->write(tty, &ch, 1);
3002 EXPORT_SYMBOL_GPL(tty_put_char);
3004 struct class *tty_class;
3006 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3007 unsigned int index, unsigned int count)
3009 /* init here, since reused cdevs cause crashes */
3010 cdev_init(&driver->cdevs[index], &tty_fops);
3011 driver->cdevs[index].owner = driver->owner;
3012 return cdev_add(&driver->cdevs[index], dev, count);
3016 * tty_register_device - register a tty device
3017 * @driver: the tty driver that describes the tty device
3018 * @index: the index in the tty driver for this tty device
3019 * @device: a struct device that is associated with this tty device.
3020 * This field is optional, if there is no known struct device
3021 * for this tty device it can be set to NULL safely.
3023 * Returns a pointer to the struct device for this tty device
3024 * (or ERR_PTR(-EFOO) on error).
3026 * This call is required to be made to register an individual tty device
3027 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3028 * that bit is not set, this function should not be called by a tty
3034 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3035 struct device *device)
3037 return tty_register_device_attr(driver, index, device, NULL, NULL);
3039 EXPORT_SYMBOL(tty_register_device);
3041 static void tty_device_create_release(struct device *dev)
3043 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3048 * tty_register_device_attr - register a tty device
3049 * @driver: the tty driver that describes the tty device
3050 * @index: the index in the tty driver for this tty device
3051 * @device: a struct device that is associated with this tty device.
3052 * This field is optional, if there is no known struct device
3053 * for this tty device it can be set to NULL safely.
3054 * @drvdata: Driver data to be set to device.
3055 * @attr_grp: Attribute group to be set on device.
3057 * Returns a pointer to the struct device for this tty device
3058 * (or ERR_PTR(-EFOO) on error).
3060 * This call is required to be made to register an individual tty device
3061 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3062 * that bit is not set, this function should not be called by a tty
3067 struct device *tty_register_device_attr(struct tty_driver *driver,
3068 unsigned index, struct device *device,
3070 const struct attribute_group **attr_grp)
3073 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3074 struct device *dev = NULL;
3075 int retval = -ENODEV;
3078 if (index >= driver->num) {
3079 printk(KERN_ERR "Attempt to register invalid tty line number "
3081 return ERR_PTR(-EINVAL);
3084 if (driver->type == TTY_DRIVER_TYPE_PTY)
3085 pty_line_name(driver, index, name);
3087 tty_line_name(driver, index, name);
3089 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3090 retval = tty_cdev_add(driver, devt, index, 1);
3096 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3103 dev->class = tty_class;
3104 dev->parent = device;
3105 dev->release = tty_device_create_release;
3106 dev_set_name(dev, "%s", name);
3107 dev->groups = attr_grp;
3108 dev_set_drvdata(dev, drvdata);
3110 retval = device_register(dev);
3119 cdev_del(&driver->cdevs[index]);
3120 return ERR_PTR(retval);
3122 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3125 * tty_unregister_device - unregister a tty device
3126 * @driver: the tty driver that describes the tty device
3127 * @index: the index in the tty driver for this tty device
3129 * If a tty device is registered with a call to tty_register_device() then
3130 * this function must be called when the tty device is gone.
3135 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3137 device_destroy(tty_class,
3138 MKDEV(driver->major, driver->minor_start) + index);
3139 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3140 cdev_del(&driver->cdevs[index]);
3142 EXPORT_SYMBOL(tty_unregister_device);
3145 * __tty_alloc_driver -- allocate tty driver
3146 * @lines: count of lines this driver can handle at most
3147 * @owner: module which is repsonsible for this driver
3148 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3150 * This should not be called directly, some of the provided macros should be
3151 * used instead. Use IS_ERR and friends on @retval.
3153 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3154 unsigned long flags)
3156 struct tty_driver *driver;
3157 unsigned int cdevs = 1;
3160 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3161 return ERR_PTR(-EINVAL);
3163 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3165 return ERR_PTR(-ENOMEM);
3167 kref_init(&driver->kref);
3168 driver->magic = TTY_DRIVER_MAGIC;
3169 driver->num = lines;
3170 driver->owner = owner;
3171 driver->flags = flags;
3173 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3174 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3176 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3178 if (!driver->ttys || !driver->termios) {
3184 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3185 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3187 if (!driver->ports) {
3194 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3195 if (!driver->cdevs) {
3202 kfree(driver->ports);
3203 kfree(driver->ttys);
3204 kfree(driver->termios);
3206 return ERR_PTR(err);
3208 EXPORT_SYMBOL(__tty_alloc_driver);
3210 static void destruct_tty_driver(struct kref *kref)
3212 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3214 struct ktermios *tp;
3216 if (driver->flags & TTY_DRIVER_INSTALLED) {
3218 * Free the termios and termios_locked structures because
3219 * we don't want to get memory leaks when modular tty
3220 * drivers are removed from the kernel.
3222 for (i = 0; i < driver->num; i++) {
3223 tp = driver->termios[i];
3225 driver->termios[i] = NULL;
3228 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3229 tty_unregister_device(driver, i);
3231 proc_tty_unregister_driver(driver);
3232 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3233 cdev_del(&driver->cdevs[0]);
3235 kfree(driver->cdevs);
3236 kfree(driver->ports);
3237 kfree(driver->termios);
3238 kfree(driver->ttys);
3242 void tty_driver_kref_put(struct tty_driver *driver)
3244 kref_put(&driver->kref, destruct_tty_driver);
3246 EXPORT_SYMBOL(tty_driver_kref_put);
3248 void tty_set_operations(struct tty_driver *driver,
3249 const struct tty_operations *op)
3253 EXPORT_SYMBOL(tty_set_operations);
3255 void put_tty_driver(struct tty_driver *d)
3257 tty_driver_kref_put(d);
3259 EXPORT_SYMBOL(put_tty_driver);
3262 * Called by a tty driver to register itself.
3264 int tty_register_driver(struct tty_driver *driver)
3271 if (!driver->major) {
3272 error = alloc_chrdev_region(&dev, driver->minor_start,
3273 driver->num, driver->name);
3275 driver->major = MAJOR(dev);
3276 driver->minor_start = MINOR(dev);
3279 dev = MKDEV(driver->major, driver->minor_start);
3280 error = register_chrdev_region(dev, driver->num, driver->name);
3285 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3286 error = tty_cdev_add(driver, dev, 0, driver->num);
3288 goto err_unreg_char;
3291 mutex_lock(&tty_mutex);
3292 list_add(&driver->tty_drivers, &tty_drivers);
3293 mutex_unlock(&tty_mutex);
3295 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3296 for (i = 0; i < driver->num; i++) {
3297 d = tty_register_device(driver, i, NULL);
3300 goto err_unreg_devs;
3304 proc_tty_register_driver(driver);
3305 driver->flags |= TTY_DRIVER_INSTALLED;
3309 for (i--; i >= 0; i--)
3310 tty_unregister_device(driver, i);
3312 mutex_lock(&tty_mutex);
3313 list_del(&driver->tty_drivers);
3314 mutex_unlock(&tty_mutex);
3317 unregister_chrdev_region(dev, driver->num);
3321 EXPORT_SYMBOL(tty_register_driver);
3324 * Called by a tty driver to unregister itself.
3326 int tty_unregister_driver(struct tty_driver *driver)
3330 if (driver->refcount)
3333 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3335 mutex_lock(&tty_mutex);
3336 list_del(&driver->tty_drivers);
3337 mutex_unlock(&tty_mutex);
3341 EXPORT_SYMBOL(tty_unregister_driver);
3343 dev_t tty_devnum(struct tty_struct *tty)
3345 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3347 EXPORT_SYMBOL(tty_devnum);
3349 void proc_clear_tty(struct task_struct *p)
3351 unsigned long flags;
3352 struct tty_struct *tty;
3353 spin_lock_irqsave(&p->sighand->siglock, flags);
3354 tty = p->signal->tty;
3355 p->signal->tty = NULL;
3356 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3360 /* Called under the sighand lock */
3362 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3365 unsigned long flags;
3366 /* We should not have a session or pgrp to put here but.... */
3367 spin_lock_irqsave(&tty->ctrl_lock, flags);
3368 put_pid(tty->session);
3370 tty->pgrp = get_pid(task_pgrp(tsk));
3371 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3372 tty->session = get_pid(task_session(tsk));
3373 if (tsk->signal->tty) {
3374 printk(KERN_DEBUG "tty not NULL!!\n");
3375 tty_kref_put(tsk->signal->tty);
3378 put_pid(tsk->signal->tty_old_pgrp);
3379 tsk->signal->tty = tty_kref_get(tty);
3380 tsk->signal->tty_old_pgrp = NULL;
3383 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3385 spin_lock_irq(&tsk->sighand->siglock);
3386 __proc_set_tty(tsk, tty);
3387 spin_unlock_irq(&tsk->sighand->siglock);
3390 struct tty_struct *get_current_tty(void)
3392 struct tty_struct *tty;
3393 unsigned long flags;
3395 spin_lock_irqsave(¤t->sighand->siglock, flags);
3396 tty = tty_kref_get(current->signal->tty);
3397 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3400 EXPORT_SYMBOL_GPL(get_current_tty);
3402 void tty_default_fops(struct file_operations *fops)
3408 * Initialize the console device. This is called *early*, so
3409 * we can't necessarily depend on lots of kernel help here.
3410 * Just do some early initializations, and do the complex setup
3413 void __init console_init(void)
3417 /* Setup the default TTY line discipline. */
3421 * set up the console device so that later boot sequences can
3422 * inform about problems etc..
3424 call = __con_initcall_start;
3425 while (call < __con_initcall_end) {
3431 static char *tty_devnode(struct device *dev, umode_t *mode)
3435 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3436 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3441 static int __init tty_class_init(void)
3443 tty_class = class_create(THIS_MODULE, "tty");
3444 if (IS_ERR(tty_class))
3445 return PTR_ERR(tty_class);
3446 tty_class->devnode = tty_devnode;
3450 postcore_initcall(tty_class_init);
3452 /* 3/2004 jmc: why do these devices exist? */
3453 static struct cdev tty_cdev, console_cdev;
3455 static ssize_t show_cons_active(struct device *dev,
3456 struct device_attribute *attr, char *buf)
3458 struct console *cs[16];
3464 for_each_console(c) {
3469 if ((c->flags & CON_ENABLED) == 0)
3472 if (i >= ARRAY_SIZE(cs))
3476 count += sprintf(buf + count, "%s%d%c",
3477 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3482 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3484 static struct device *consdev;
3486 void console_sysfs_notify(void)
3489 sysfs_notify(&consdev->kobj, NULL, "active");
3493 * Ok, now we can initialize the rest of the tty devices and can count
3494 * on memory allocations, interrupts etc..
3496 int __init tty_init(void)
3498 cdev_init(&tty_cdev, &tty_fops);
3499 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3500 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3501 panic("Couldn't register /dev/tty driver\n");
3502 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3504 cdev_init(&console_cdev, &console_fops);
3505 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3506 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3507 panic("Couldn't register /dev/console driver\n");
3508 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3510 if (IS_ERR(consdev))
3513 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3516 vty_init(&console_fops);