2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched.h>
73 #include <linux/interrupt.h>
74 #include <linux/tty.h>
75 #include <linux/tty_driver.h>
76 #include <linux/tty_flip.h>
77 #include <linux/devpts_fs.h>
78 #include <linux/file.h>
79 #include <linux/fdtable.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/device.h>
92 #include <linux/wait.h>
93 #include <linux/bitops.h>
94 #include <linux/delay.h>
95 #include <linux/seq_file.h>
96 #include <linux/serial.h>
97 #include <linux/ratelimit.h>
99 #include <linux/uaccess.h>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
106 #include <linux/nsproxy.h>
108 #undef TTY_DEBUG_HANGUP
109 #ifdef TTY_DEBUG_HANGUP
110 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
112 # define tty_debug_hangup(tty, f, args...) do { } while (0)
115 #define TTY_PARANOIA_CHECK 1
116 #define CHECK_TTY_COUNT 1
118 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
119 .c_iflag = ICRNL | IXON,
120 .c_oflag = OPOST | ONLCR,
121 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
122 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
123 ECHOCTL | ECHOKE | IEXTEN,
129 EXPORT_SYMBOL(tty_std_termios);
131 /* This list gets poked at by procfs and various bits of boot up code. This
132 could do with some rationalisation such as pulling the tty proc function
135 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
137 /* Mutex to protect creating and releasing a tty. This is shared with
138 vt.c for deeply disgusting hack reasons */
139 DEFINE_MUTEX(tty_mutex);
140 EXPORT_SYMBOL(tty_mutex);
142 /* Spinlock to protect the tty->tty_files list */
143 DEFINE_SPINLOCK(tty_files_lock);
145 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
146 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
147 ssize_t redirected_tty_write(struct file *, const char __user *,
149 static unsigned int tty_poll(struct file *, poll_table *);
150 static int tty_open(struct inode *, struct file *);
151 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
153 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
156 #define tty_compat_ioctl NULL
158 static int __tty_fasync(int fd, struct file *filp, int on);
159 static int tty_fasync(int fd, struct file *filp, int on);
160 static void release_tty(struct tty_struct *tty, int idx);
163 * free_tty_struct - free a disused tty
164 * @tty: tty struct to free
166 * Free the write buffers, tty queue and tty memory itself.
168 * Locking: none. Must be called after tty is definitely unused
171 void free_tty_struct(struct tty_struct *tty)
175 put_device(tty->dev);
176 kfree(tty->write_buf);
177 tty->magic = 0xDEADDEAD;
181 static inline struct tty_struct *file_tty(struct file *file)
183 return ((struct tty_file_private *)file->private_data)->tty;
186 int tty_alloc_file(struct file *file)
188 struct tty_file_private *priv;
190 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
194 file->private_data = priv;
199 /* Associate a new file with the tty structure */
200 void tty_add_file(struct tty_struct *tty, struct file *file)
202 struct tty_file_private *priv = file->private_data;
207 spin_lock(&tty_files_lock);
208 list_add(&priv->list, &tty->tty_files);
209 spin_unlock(&tty_files_lock);
213 * tty_free_file - free file->private_data
215 * This shall be used only for fail path handling when tty_add_file was not
218 void tty_free_file(struct file *file)
220 struct tty_file_private *priv = file->private_data;
222 file->private_data = NULL;
226 /* Delete file from its tty */
227 static void tty_del_file(struct file *file)
229 struct tty_file_private *priv = file->private_data;
231 spin_lock(&tty_files_lock);
232 list_del(&priv->list);
233 spin_unlock(&tty_files_lock);
238 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
241 * tty_name - return tty naming
242 * @tty: tty structure
244 * Convert a tty structure into a name. The name reflects the kernel
245 * naming policy and if udev is in use may not reflect user space
250 const char *tty_name(const struct tty_struct *tty)
252 if (!tty) /* Hmm. NULL pointer. That's fun. */
257 EXPORT_SYMBOL(tty_name);
259 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
262 #ifdef TTY_PARANOIA_CHECK
265 "null TTY for (%d:%d) in %s\n",
266 imajor(inode), iminor(inode), routine);
269 if (tty->magic != TTY_MAGIC) {
271 "bad magic number for tty struct (%d:%d) in %s\n",
272 imajor(inode), iminor(inode), routine);
279 /* Caller must hold tty_lock */
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 (!len || 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, int sig)
396 struct pid *pgrp, *tty_pgrp;
399 if (current->signal->tty != tty)
403 pgrp = task_pgrp(current);
405 spin_lock_irqsave(&tty->ctrl_lock, flags);
406 tty_pgrp = tty->pgrp;
407 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
409 if (tty_pgrp && pgrp != tty->pgrp) {
410 if (is_ignored(sig)) {
413 } else if (is_current_pgrp_orphaned())
416 kill_pgrp(pgrp, sig, 1);
417 set_thread_flag(TIF_SIGPENDING);
424 pr_warn("%s: tty_check_change: sig=%d, tty->pgrp == NULL!\n",
431 int tty_check_change(struct tty_struct *tty)
433 return __tty_check_change(tty, SIGTTOU);
435 EXPORT_SYMBOL(tty_check_change);
437 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
438 size_t count, loff_t *ppos)
443 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
444 size_t count, loff_t *ppos)
449 /* No kernel lock held - none needed ;) */
450 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
452 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
455 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
458 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
461 static long hung_up_tty_compat_ioctl(struct file *file,
462 unsigned int cmd, unsigned long arg)
464 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
467 static const struct file_operations tty_fops = {
472 .unlocked_ioctl = tty_ioctl,
473 .compat_ioctl = tty_compat_ioctl,
475 .release = tty_release,
476 .fasync = tty_fasync,
479 static const struct file_operations console_fops = {
482 .write = redirected_tty_write,
484 .unlocked_ioctl = tty_ioctl,
485 .compat_ioctl = tty_compat_ioctl,
487 .release = tty_release,
488 .fasync = tty_fasync,
491 static const struct file_operations hung_up_tty_fops = {
493 .read = hung_up_tty_read,
494 .write = hung_up_tty_write,
495 .poll = hung_up_tty_poll,
496 .unlocked_ioctl = hung_up_tty_ioctl,
497 .compat_ioctl = hung_up_tty_compat_ioctl,
498 .release = tty_release,
501 static DEFINE_SPINLOCK(redirect_lock);
502 static struct file *redirect;
505 void proc_clear_tty(struct task_struct *p)
508 struct tty_struct *tty;
509 spin_lock_irqsave(&p->sighand->siglock, flags);
510 tty = p->signal->tty;
511 p->signal->tty = NULL;
512 spin_unlock_irqrestore(&p->sighand->siglock, flags);
516 extern void tty_sysctl_init(void);
519 * proc_set_tty - set the controlling terminal
521 * Only callable by the session leader and only if it does not already have
522 * a controlling terminal.
524 * Caller must hold: tty_lock()
525 * a readlock on tasklist_lock
528 static void __proc_set_tty(struct tty_struct *tty)
532 spin_lock_irqsave(&tty->ctrl_lock, flags);
534 * The session and fg pgrp references will be non-NULL if
535 * tiocsctty() is stealing the controlling tty
537 put_pid(tty->session);
539 tty->pgrp = get_pid(task_pgrp(current));
540 tty->session = get_pid(task_session(current));
541 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
542 if (current->signal->tty) {
543 tty_debug(tty, "current tty %s not NULL!!\n",
544 current->signal->tty->name);
545 tty_kref_put(current->signal->tty);
547 put_pid(current->signal->tty_old_pgrp);
548 current->signal->tty = tty_kref_get(tty);
549 current->signal->tty_old_pgrp = NULL;
552 static void proc_set_tty(struct tty_struct *tty)
554 spin_lock_irq(¤t->sighand->siglock);
556 spin_unlock_irq(¤t->sighand->siglock);
559 struct tty_struct *get_current_tty(void)
561 struct tty_struct *tty;
564 spin_lock_irqsave(¤t->sighand->siglock, flags);
565 tty = tty_kref_get(current->signal->tty);
566 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
569 EXPORT_SYMBOL_GPL(get_current_tty);
571 static void session_clear_tty(struct pid *session)
573 struct task_struct *p;
574 do_each_pid_task(session, PIDTYPE_SID, p) {
576 } while_each_pid_task(session, PIDTYPE_SID, p);
580 * tty_wakeup - request more data
583 * Internal and external helper for wakeups of tty. This function
584 * informs the line discipline if present that the driver is ready
585 * to receive more output data.
588 void tty_wakeup(struct tty_struct *tty)
590 struct tty_ldisc *ld;
592 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
593 ld = tty_ldisc_ref(tty);
595 if (ld->ops->write_wakeup)
596 ld->ops->write_wakeup(tty);
600 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
603 EXPORT_SYMBOL_GPL(tty_wakeup);
606 * tty_signal_session_leader - sends SIGHUP to session leader
607 * @tty controlling tty
608 * @exit_session if non-zero, signal all foreground group processes
610 * Send SIGHUP and SIGCONT to the session leader and its process group.
611 * Optionally, signal all processes in the foreground process group.
613 * Returns the number of processes in the session with this tty
614 * as their controlling terminal. This value is used to drop
615 * tty references for those processes.
617 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
619 struct task_struct *p;
621 struct pid *tty_pgrp = NULL;
623 read_lock(&tasklist_lock);
625 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
626 spin_lock_irq(&p->sighand->siglock);
627 if (p->signal->tty == tty) {
628 p->signal->tty = NULL;
629 /* We defer the dereferences outside fo
633 if (!p->signal->leader) {
634 spin_unlock_irq(&p->sighand->siglock);
637 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
638 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
639 put_pid(p->signal->tty_old_pgrp); /* A noop */
640 spin_lock(&tty->ctrl_lock);
641 tty_pgrp = get_pid(tty->pgrp);
643 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
644 spin_unlock(&tty->ctrl_lock);
645 spin_unlock_irq(&p->sighand->siglock);
646 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
648 read_unlock(&tasklist_lock);
652 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
660 * __tty_hangup - actual handler for hangup events
663 * This can be called by a "kworker" kernel thread. That is process
664 * synchronous but doesn't hold any locks, so we need to make sure we
665 * have the appropriate locks for what we're doing.
667 * The hangup event clears any pending redirections onto the hung up
668 * device. It ensures future writes will error and it does the needed
669 * line discipline hangup and signal delivery. The tty object itself
674 * redirect lock for undoing redirection
675 * file list lock for manipulating list of ttys
676 * tty_ldiscs_lock from called functions
677 * termios_rwsem resetting termios data
678 * tasklist_lock to walk task list for hangup event
679 * ->siglock to protect ->signal/->sighand
681 static void __tty_hangup(struct tty_struct *tty, int exit_session)
683 struct file *cons_filp = NULL;
684 struct file *filp, *f = NULL;
685 struct tty_file_private *priv;
686 int closecount = 0, n;
693 spin_lock(&redirect_lock);
694 if (redirect && file_tty(redirect) == tty) {
698 spin_unlock(&redirect_lock);
702 if (test_bit(TTY_HUPPED, &tty->flags)) {
708 * Some console devices aren't actually hung up for technical and
709 * historical reasons, which can lead to indefinite interruptible
710 * sleep in n_tty_read(). The following explicitly tells
711 * n_tty_read() to abort readers.
713 set_bit(TTY_HUPPING, &tty->flags);
715 /* inuse_filps is protected by the single tty lock,
716 this really needs to change if we want to flush the
717 workqueue with the lock held */
718 check_tty_count(tty, "tty_hangup");
720 spin_lock(&tty_files_lock);
721 /* This breaks for file handles being sent over AF_UNIX sockets ? */
722 list_for_each_entry(priv, &tty->tty_files, list) {
724 if (filp->f_op->write == redirected_tty_write)
726 if (filp->f_op->write != tty_write)
729 __tty_fasync(-1, filp, 0); /* can't block */
730 filp->f_op = &hung_up_tty_fops;
732 spin_unlock(&tty_files_lock);
734 refs = tty_signal_session_leader(tty, exit_session);
735 /* Account for the p->signal references we killed */
739 tty_ldisc_hangup(tty);
741 spin_lock_irq(&tty->ctrl_lock);
742 clear_bit(TTY_THROTTLED, &tty->flags);
743 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
744 put_pid(tty->session);
748 tty->ctrl_status = 0;
749 spin_unlock_irq(&tty->ctrl_lock);
752 * If one of the devices matches a console pointer, we
753 * cannot just call hangup() because that will cause
754 * tty->count and state->count to go out of sync.
755 * So we just call close() the right number of times.
759 for (n = 0; n < closecount; n++)
760 tty->ops->close(tty, cons_filp);
761 } else if (tty->ops->hangup)
762 tty->ops->hangup(tty);
764 * We don't want to have driver/ldisc interactions beyond
765 * the ones we did here. The driver layer expects no
766 * calls after ->hangup() from the ldisc side. However we
767 * can't yet guarantee all that.
769 set_bit(TTY_HUPPED, &tty->flags);
770 clear_bit(TTY_HUPPING, &tty->flags);
777 static void do_tty_hangup(struct work_struct *work)
779 struct tty_struct *tty =
780 container_of(work, struct tty_struct, hangup_work);
782 __tty_hangup(tty, 0);
786 * tty_hangup - trigger a hangup event
787 * @tty: tty to hangup
789 * A carrier loss (virtual or otherwise) has occurred on this like
790 * schedule a hangup sequence to run after this event.
793 void tty_hangup(struct tty_struct *tty)
795 tty_debug_hangup(tty, "\n");
796 schedule_work(&tty->hangup_work);
799 EXPORT_SYMBOL(tty_hangup);
802 * tty_vhangup - process vhangup
803 * @tty: tty to hangup
805 * The user has asked via system call for the terminal to be hung up.
806 * We do this synchronously so that when the syscall returns the process
807 * is complete. That guarantee is necessary for security reasons.
810 void tty_vhangup(struct tty_struct *tty)
812 tty_debug_hangup(tty, "\n");
813 __tty_hangup(tty, 0);
816 EXPORT_SYMBOL(tty_vhangup);
820 * tty_vhangup_self - process vhangup for own ctty
822 * Perform a vhangup on the current controlling tty
825 void tty_vhangup_self(void)
827 struct tty_struct *tty;
829 tty = get_current_tty();
837 * tty_vhangup_session - hangup session leader exit
838 * @tty: tty to hangup
840 * The session leader is exiting and hanging up its controlling terminal.
841 * Every process in the foreground process group is signalled SIGHUP.
843 * We do this synchronously so that when the syscall returns the process
844 * is complete. That guarantee is necessary for security reasons.
847 static void tty_vhangup_session(struct tty_struct *tty)
849 tty_debug_hangup(tty, "\n");
850 __tty_hangup(tty, 1);
854 * tty_hung_up_p - was tty hung up
855 * @filp: file pointer of tty
857 * Return true if the tty has been subject to a vhangup or a carrier
861 int tty_hung_up_p(struct file *filp)
863 return (filp->f_op == &hung_up_tty_fops);
866 EXPORT_SYMBOL(tty_hung_up_p);
869 * disassociate_ctty - disconnect controlling tty
870 * @on_exit: true if exiting so need to "hang up" the session
872 * This function is typically called only by the session leader, when
873 * it wants to disassociate itself from its controlling tty.
875 * It performs the following functions:
876 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
877 * (2) Clears the tty from being controlling the session
878 * (3) Clears the controlling tty for all processes in the
881 * The argument on_exit is set to 1 if called when a process is
882 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
885 * BTM is taken for hysterical raisins, and held when
886 * called from no_tty().
887 * tty_mutex is taken to protect tty
888 * ->siglock is taken to protect ->signal/->sighand
889 * tasklist_lock is taken to walk process list for sessions
890 * ->siglock is taken to protect ->signal/->sighand
893 void disassociate_ctty(int on_exit)
895 struct tty_struct *tty;
897 if (!current->signal->leader)
900 tty = get_current_tty();
902 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
903 tty_vhangup_session(tty);
905 struct pid *tty_pgrp = tty_get_pgrp(tty);
907 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
909 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
915 } else if (on_exit) {
916 struct pid *old_pgrp;
917 spin_lock_irq(¤t->sighand->siglock);
918 old_pgrp = current->signal->tty_old_pgrp;
919 current->signal->tty_old_pgrp = NULL;
920 spin_unlock_irq(¤t->sighand->siglock);
922 kill_pgrp(old_pgrp, SIGHUP, on_exit);
923 kill_pgrp(old_pgrp, SIGCONT, on_exit);
929 spin_lock_irq(¤t->sighand->siglock);
930 put_pid(current->signal->tty_old_pgrp);
931 current->signal->tty_old_pgrp = NULL;
932 tty = tty_kref_get(current->signal->tty);
933 spin_unlock_irq(¤t->sighand->siglock);
939 spin_lock_irqsave(&tty->ctrl_lock, flags);
940 put_pid(tty->session);
944 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
948 tty_debug_hangup(tty, "no current tty\n");
950 /* Now clear signal->tty under the lock */
951 read_lock(&tasklist_lock);
952 session_clear_tty(task_session(current));
953 read_unlock(&tasklist_lock);
958 * no_tty - Ensure the current process does not have a controlling tty
962 /* FIXME: Review locking here. The tty_lock never covered any race
963 between a new association and proc_clear_tty but possible we need
964 to protect against this anyway */
965 struct task_struct *tsk = current;
966 disassociate_ctty(0);
972 * stop_tty - propagate flow control
975 * Perform flow control to the driver. May be called
976 * on an already stopped device and will not re-call the driver
979 * This functionality is used by both the line disciplines for
980 * halting incoming flow and by the driver. It may therefore be
981 * called from any context, may be under the tty atomic_write_lock
988 void __stop_tty(struct tty_struct *tty)
997 void stop_tty(struct tty_struct *tty)
1001 spin_lock_irqsave(&tty->flow_lock, flags);
1003 spin_unlock_irqrestore(&tty->flow_lock, flags);
1005 EXPORT_SYMBOL(stop_tty);
1008 * start_tty - propagate flow control
1009 * @tty: tty to start
1011 * Start a tty that has been stopped if at all possible. If this
1012 * tty was previous stopped and is now being started, the driver
1013 * start method is invoked and the line discipline woken.
1019 void __start_tty(struct tty_struct *tty)
1021 if (!tty->stopped || tty->flow_stopped)
1024 if (tty->ops->start)
1025 tty->ops->start(tty);
1029 void start_tty(struct tty_struct *tty)
1031 unsigned long flags;
1033 spin_lock_irqsave(&tty->flow_lock, flags);
1035 spin_unlock_irqrestore(&tty->flow_lock, flags);
1037 EXPORT_SYMBOL(start_tty);
1039 static void tty_update_time(struct timespec *time)
1041 unsigned long sec = get_seconds();
1044 * We only care if the two values differ in anything other than the
1045 * lower three bits (i.e every 8 seconds). If so, then we can update
1046 * the time of the tty device, otherwise it could be construded as a
1047 * security leak to let userspace know the exact timing of the tty.
1049 if ((sec ^ time->tv_sec) & ~7)
1054 * tty_read - read method for tty device files
1055 * @file: pointer to tty file
1057 * @count: size of user buffer
1060 * Perform the read system call function on this terminal device. Checks
1061 * for hung up devices before calling the line discipline method.
1064 * Locks the line discipline internally while needed. Multiple
1065 * read calls may be outstanding in parallel.
1068 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1072 struct inode *inode = file_inode(file);
1073 struct tty_struct *tty = file_tty(file);
1074 struct tty_ldisc *ld;
1076 if (tty_paranoia_check(tty, inode, "tty_read"))
1078 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1081 /* We want to wait for the line discipline to sort out in this
1083 ld = tty_ldisc_ref_wait(tty);
1085 i = ld->ops->read(tty, file, buf, count);
1088 tty_ldisc_deref(ld);
1091 tty_update_time(&inode->i_atime);
1096 static void tty_write_unlock(struct tty_struct *tty)
1098 mutex_unlock(&tty->atomic_write_lock);
1099 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1102 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1104 if (!mutex_trylock(&tty->atomic_write_lock)) {
1107 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1108 return -ERESTARTSYS;
1114 * Split writes up in sane blocksizes to avoid
1115 * denial-of-service type attacks
1117 static inline ssize_t do_tty_write(
1118 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1119 struct tty_struct *tty,
1121 const char __user *buf,
1124 ssize_t ret, written = 0;
1127 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1132 * We chunk up writes into a temporary buffer. This
1133 * simplifies low-level drivers immensely, since they
1134 * don't have locking issues and user mode accesses.
1136 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1139 * The default chunk-size is 2kB, because the NTTY
1140 * layer has problems with bigger chunks. It will
1141 * claim to be able to handle more characters than
1144 * FIXME: This can probably go away now except that 64K chunks
1145 * are too likely to fail unless switched to vmalloc...
1148 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1153 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1154 if (tty->write_cnt < chunk) {
1155 unsigned char *buf_chunk;
1160 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1165 kfree(tty->write_buf);
1166 tty->write_cnt = chunk;
1167 tty->write_buf = buf_chunk;
1170 /* Do the write .. */
1172 size_t size = count;
1176 if (copy_from_user(tty->write_buf, buf, size))
1178 ret = write(tty, file, tty->write_buf, size);
1187 if (signal_pending(current))
1192 tty_update_time(&file_inode(file)->i_mtime);
1196 tty_write_unlock(tty);
1201 * tty_write_message - write a message to a certain tty, not just the console.
1202 * @tty: the destination tty_struct
1203 * @msg: the message to write
1205 * This is used for messages that need to be redirected to a specific tty.
1206 * We don't put it into the syslog queue right now maybe in the future if
1209 * We must still hold the BTM and test the CLOSING flag for the moment.
1212 void tty_write_message(struct tty_struct *tty, char *msg)
1215 mutex_lock(&tty->atomic_write_lock);
1217 if (tty->ops->write && tty->count > 0)
1218 tty->ops->write(tty, msg, strlen(msg));
1220 tty_write_unlock(tty);
1227 * tty_write - write method for tty device file
1228 * @file: tty file pointer
1229 * @buf: user data to write
1230 * @count: bytes to write
1233 * Write data to a tty device via the line discipline.
1236 * Locks the line discipline as required
1237 * Writes to the tty driver are serialized by the atomic_write_lock
1238 * and are then processed in chunks to the device. The line discipline
1239 * write method will not be invoked in parallel for each device.
1242 static ssize_t tty_write(struct file *file, const char __user *buf,
1243 size_t count, loff_t *ppos)
1245 struct tty_struct *tty = file_tty(file);
1246 struct tty_ldisc *ld;
1249 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1251 if (!tty || !tty->ops->write ||
1252 (test_bit(TTY_IO_ERROR, &tty->flags)))
1254 /* Short term debug to catch buggy drivers */
1255 if (tty->ops->write_room == NULL)
1256 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1258 ld = tty_ldisc_ref_wait(tty);
1259 if (!ld->ops->write)
1262 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1263 tty_ldisc_deref(ld);
1267 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1268 size_t count, loff_t *ppos)
1270 struct file *p = NULL;
1272 spin_lock(&redirect_lock);
1274 p = get_file(redirect);
1275 spin_unlock(&redirect_lock);
1279 res = vfs_write(p, buf, count, &p->f_pos);
1283 return tty_write(file, buf, count, ppos);
1287 * tty_send_xchar - send priority character
1289 * Send a high priority character to the tty even if stopped
1291 * Locking: none for xchar method, write ordering for write method.
1294 int tty_send_xchar(struct tty_struct *tty, char ch)
1296 int was_stopped = tty->stopped;
1298 if (tty->ops->send_xchar) {
1299 down_read(&tty->termios_rwsem);
1300 tty->ops->send_xchar(tty, ch);
1301 up_read(&tty->termios_rwsem);
1305 if (tty_write_lock(tty, 0) < 0)
1306 return -ERESTARTSYS;
1308 down_read(&tty->termios_rwsem);
1311 tty->ops->write(tty, &ch, 1);
1314 up_read(&tty->termios_rwsem);
1315 tty_write_unlock(tty);
1319 static char ptychar[] = "pqrstuvwxyzabcde";
1322 * pty_line_name - generate name for a pty
1323 * @driver: the tty driver in use
1324 * @index: the minor number
1325 * @p: output buffer of at least 6 bytes
1327 * Generate a name from a driver reference and write it to the output
1332 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1334 int i = index + driver->name_base;
1335 /* ->name is initialized to "ttyp", but "tty" is expected */
1336 sprintf(p, "%s%c%x",
1337 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1338 ptychar[i >> 4 & 0xf], i & 0xf);
1342 * tty_line_name - generate name for a tty
1343 * @driver: the tty driver in use
1344 * @index: the minor number
1345 * @p: output buffer of at least 7 bytes
1347 * Generate a name from a driver reference and write it to the output
1352 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1354 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1355 return sprintf(p, "%s", driver->name);
1357 return sprintf(p, "%s%d", driver->name,
1358 index + driver->name_base);
1362 * tty_driver_lookup_tty() - find an existing tty, if any
1363 * @driver: the driver for the tty
1364 * @idx: the minor number
1366 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1367 * driver lookup() method returns an error.
1369 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1371 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1372 struct inode *inode, int idx)
1374 struct tty_struct *tty;
1376 if (driver->ops->lookup)
1377 tty = driver->ops->lookup(driver, inode, idx);
1379 tty = driver->ttys[idx];
1387 * tty_init_termios - helper for termios setup
1388 * @tty: the tty to set up
1390 * Initialise the termios structures for this tty. Thus runs under
1391 * the tty_mutex currently so we can be relaxed about ordering.
1394 int tty_init_termios(struct tty_struct *tty)
1396 struct ktermios *tp;
1397 int idx = tty->index;
1399 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1400 tty->termios = tty->driver->init_termios;
1402 /* Check for lazy saved data */
1403 tp = tty->driver->termios[idx];
1407 tty->termios = tty->driver->init_termios;
1409 /* Compatibility until drivers always set this */
1410 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1411 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1414 EXPORT_SYMBOL_GPL(tty_init_termios);
1416 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1418 int ret = tty_init_termios(tty);
1422 tty_driver_kref_get(driver);
1424 driver->ttys[tty->index] = tty;
1427 EXPORT_SYMBOL_GPL(tty_standard_install);
1430 * tty_driver_install_tty() - install a tty entry in the driver
1431 * @driver: the driver for the tty
1434 * Install a tty object into the driver tables. The tty->index field
1435 * will be set by the time this is called. This method is responsible
1436 * for ensuring any need additional structures are allocated and
1439 * Locking: tty_mutex for now
1441 static int tty_driver_install_tty(struct tty_driver *driver,
1442 struct tty_struct *tty)
1444 return driver->ops->install ? driver->ops->install(driver, tty) :
1445 tty_standard_install(driver, tty);
1449 * tty_driver_remove_tty() - remove a tty from the driver tables
1450 * @driver: the driver for the tty
1451 * @idx: the minor number
1453 * Remvoe a tty object from the driver tables. The tty->index field
1454 * will be set by the time this is called.
1456 * Locking: tty_mutex for now
1458 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1460 if (driver->ops->remove)
1461 driver->ops->remove(driver, tty);
1463 driver->ttys[tty->index] = NULL;
1467 * tty_reopen() - fast re-open of an open tty
1468 * @tty - the tty to open
1470 * Return 0 on success, -errno on error.
1471 * Re-opens on master ptys are not allowed and return -EIO.
1473 * Locking: Caller must hold tty_lock
1475 static int tty_reopen(struct tty_struct *tty)
1477 struct tty_driver *driver = tty->driver;
1479 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1480 driver->subtype == PTY_TYPE_MASTER)
1486 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1491 WARN_ON(!tty->ldisc);
1497 * tty_init_dev - initialise a tty device
1498 * @driver: tty driver we are opening a device on
1499 * @idx: device index
1500 * @ret_tty: returned tty structure
1502 * Prepare a tty device. This may not be a "new" clean device but
1503 * could also be an active device. The pty drivers require special
1504 * handling because of this.
1507 * The function is called under the tty_mutex, which
1508 * protects us from the tty struct or driver itself going away.
1510 * On exit the tty device has the line discipline attached and
1511 * a reference count of 1. If a pair was created for pty/tty use
1512 * and the other was a pty master then it too has a reference count of 1.
1514 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1515 * failed open. The new code protects the open with a mutex, so it's
1516 * really quite straightforward. The mutex locking can probably be
1517 * relaxed for the (most common) case of reopening a tty.
1520 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1522 struct tty_struct *tty;
1526 * First time open is complex, especially for PTY devices.
1527 * This code guarantees that either everything succeeds and the
1528 * TTY is ready for operation, or else the table slots are vacated
1529 * and the allocated memory released. (Except that the termios
1530 * and locked termios may be retained.)
1533 if (!try_module_get(driver->owner))
1534 return ERR_PTR(-ENODEV);
1536 tty = alloc_tty_struct(driver, idx);
1539 goto err_module_put;
1543 retval = tty_driver_install_tty(driver, tty);
1545 goto err_deinit_tty;
1548 tty->port = driver->ports[idx];
1550 WARN_RATELIMIT(!tty->port,
1551 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1552 __func__, tty->driver->name);
1554 tty->port->itty = tty;
1557 * Structures all installed ... call the ldisc open routines.
1558 * If we fail here just call release_tty to clean up. No need
1559 * to decrement the use counts, as release_tty doesn't care.
1561 retval = tty_ldisc_setup(tty, tty->link);
1563 goto err_release_tty;
1564 /* Return the tty locked so that it cannot vanish under the caller */
1569 deinitialize_tty_struct(tty);
1570 free_tty_struct(tty);
1572 module_put(driver->owner);
1573 return ERR_PTR(retval);
1575 /* call the tty release_tty routine to clean out this slot */
1578 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1579 "clearing slot %d\n", idx);
1580 release_tty(tty, idx);
1581 return ERR_PTR(retval);
1584 void tty_free_termios(struct tty_struct *tty)
1586 struct ktermios *tp;
1587 int idx = tty->index;
1589 /* If the port is going to reset then it has no termios to save */
1590 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1593 /* Stash the termios data */
1594 tp = tty->driver->termios[idx];
1596 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1598 pr_warn("tty: no memory to save termios state.\n");
1601 tty->driver->termios[idx] = tp;
1605 EXPORT_SYMBOL(tty_free_termios);
1608 * tty_flush_works - flush all works of a tty/pty pair
1609 * @tty: tty device to flush works for (or either end of a pty pair)
1611 * Sync flush all works belonging to @tty (and the 'other' tty).
1613 static void tty_flush_works(struct tty_struct *tty)
1615 flush_work(&tty->SAK_work);
1616 flush_work(&tty->hangup_work);
1618 flush_work(&tty->link->SAK_work);
1619 flush_work(&tty->link->hangup_work);
1624 * release_one_tty - release tty structure memory
1625 * @kref: kref of tty we are obliterating
1627 * Releases memory associated with a tty structure, and clears out the
1628 * driver table slots. This function is called when a device is no longer
1629 * in use. It also gets called when setup of a device fails.
1632 * takes the file list lock internally when working on the list
1633 * of ttys that the driver keeps.
1635 * This method gets called from a work queue so that the driver private
1636 * cleanup ops can sleep (needed for USB at least)
1638 static void release_one_tty(struct work_struct *work)
1640 struct tty_struct *tty =
1641 container_of(work, struct tty_struct, hangup_work);
1642 struct tty_driver *driver = tty->driver;
1643 struct module *owner = driver->owner;
1645 if (tty->ops->cleanup)
1646 tty->ops->cleanup(tty);
1649 tty_driver_kref_put(driver);
1652 spin_lock(&tty_files_lock);
1653 list_del_init(&tty->tty_files);
1654 spin_unlock(&tty_files_lock);
1657 put_pid(tty->session);
1658 free_tty_struct(tty);
1661 static void queue_release_one_tty(struct kref *kref)
1663 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1665 /* The hangup queue is now free so we can reuse it rather than
1666 waste a chunk of memory for each port */
1667 INIT_WORK(&tty->hangup_work, release_one_tty);
1668 schedule_work(&tty->hangup_work);
1672 * tty_kref_put - release a tty kref
1675 * Release a reference to a tty device and if need be let the kref
1676 * layer destruct the object for us
1679 void tty_kref_put(struct tty_struct *tty)
1682 kref_put(&tty->kref, queue_release_one_tty);
1684 EXPORT_SYMBOL(tty_kref_put);
1687 * release_tty - release tty structure memory
1689 * Release both @tty and a possible linked partner (think pty pair),
1690 * and decrement the refcount of the backing module.
1694 * takes the file list lock internally when working on the list
1695 * of ttys that the driver keeps.
1698 static void release_tty(struct tty_struct *tty, int idx)
1700 /* This should always be true but check for the moment */
1701 WARN_ON(tty->index != idx);
1702 WARN_ON(!mutex_is_locked(&tty_mutex));
1703 if (tty->ops->shutdown)
1704 tty->ops->shutdown(tty);
1705 tty_free_termios(tty);
1706 tty_driver_remove_tty(tty->driver, tty);
1707 tty->port->itty = NULL;
1709 tty->link->port->itty = NULL;
1710 tty_buffer_cancel_work(tty->port);
1712 tty_buffer_cancel_work(tty->link->port);
1714 tty_kref_put(tty->link);
1719 * tty_release_checks - check a tty before real release
1720 * @tty: tty to check
1721 * @o_tty: link of @tty (if any)
1722 * @idx: index of the tty
1724 * Performs some paranoid checking before true release of the @tty.
1725 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1727 static int tty_release_checks(struct tty_struct *tty, int idx)
1729 #ifdef TTY_PARANOIA_CHECK
1730 if (idx < 0 || idx >= tty->driver->num) {
1731 tty_debug(tty, "bad idx %d\n", idx);
1735 /* not much to check for devpts */
1736 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1739 if (tty != tty->driver->ttys[idx]) {
1740 tty_debug(tty, "bad driver table[%d] = %p\n",
1741 idx, tty->driver->ttys[idx]);
1744 if (tty->driver->other) {
1745 struct tty_struct *o_tty = tty->link;
1747 if (o_tty != tty->driver->other->ttys[idx]) {
1748 tty_debug(tty, "bad other table[%d] = %p\n",
1749 idx, tty->driver->other->ttys[idx]);
1752 if (o_tty->link != tty) {
1753 tty_debug(tty, "bad link = %p\n", o_tty->link);
1762 * tty_release - vfs callback for close
1763 * @inode: inode of tty
1764 * @filp: file pointer for handle to tty
1766 * Called the last time each file handle is closed that references
1767 * this tty. There may however be several such references.
1770 * Takes bkl. See tty_release_dev
1772 * Even releasing the tty structures is a tricky business.. We have
1773 * to be very careful that the structures are all released at the
1774 * same time, as interrupts might otherwise get the wrong pointers.
1776 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1777 * lead to double frees or releasing memory still in use.
1780 int tty_release(struct inode *inode, struct file *filp)
1782 struct tty_struct *tty = file_tty(filp);
1783 struct tty_struct *o_tty = NULL;
1784 int do_sleep, final;
1789 if (tty_paranoia_check(tty, inode, __func__))
1793 check_tty_count(tty, __func__);
1795 __tty_fasync(-1, filp, 0);
1798 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1799 tty->driver->subtype == PTY_TYPE_MASTER)
1802 if (tty_release_checks(tty, idx)) {
1807 tty_debug_hangup(tty, "(tty count=%d)...\n", tty->count);
1809 if (tty->ops->close)
1810 tty->ops->close(tty, filp);
1812 /* If tty is pty master, lock the slave pty (stable lock order) */
1813 tty_lock_slave(o_tty);
1816 * Sanity check: if tty->count is going to zero, there shouldn't be
1817 * any waiters on tty->read_wait or tty->write_wait. We test the
1818 * wait queues and kick everyone out _before_ actually starting to
1819 * close. This ensures that we won't block while releasing the tty
1822 * The test for the o_tty closing is necessary, since the master and
1823 * slave sides may close in any order. If the slave side closes out
1824 * first, its count will be one, since the master side holds an open.
1825 * Thus this test wouldn't be triggered at the time the slave closed,
1831 if (tty->count <= 1) {
1832 if (waitqueue_active(&tty->read_wait)) {
1833 wake_up_poll(&tty->read_wait, POLLIN);
1836 if (waitqueue_active(&tty->write_wait)) {
1837 wake_up_poll(&tty->write_wait, POLLOUT);
1841 if (o_tty && o_tty->count <= 1) {
1842 if (waitqueue_active(&o_tty->read_wait)) {
1843 wake_up_poll(&o_tty->read_wait, POLLIN);
1846 if (waitqueue_active(&o_tty->write_wait)) {
1847 wake_up_poll(&o_tty->write_wait, POLLOUT);
1856 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1857 __func__, tty_name(tty));
1859 schedule_timeout_killable(timeout);
1860 if (timeout < 120 * HZ)
1861 timeout = 2 * timeout + 1;
1863 timeout = MAX_SCHEDULE_TIMEOUT;
1867 if (--o_tty->count < 0) {
1868 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1869 __func__, o_tty->count, tty_name(o_tty));
1873 if (--tty->count < 0) {
1874 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1875 __func__, tty->count, tty_name(tty));
1880 * We've decremented tty->count, so we need to remove this file
1881 * descriptor off the tty->tty_files list; this serves two
1883 * - check_tty_count sees the correct number of file descriptors
1884 * associated with this tty.
1885 * - do_tty_hangup no longer sees this file descriptor as
1886 * something that needs to be handled for hangups.
1891 * Perform some housekeeping before deciding whether to return.
1893 * If _either_ side is closing, make sure there aren't any
1894 * processes that still think tty or o_tty is their controlling
1898 read_lock(&tasklist_lock);
1899 session_clear_tty(tty->session);
1901 session_clear_tty(o_tty->session);
1902 read_unlock(&tasklist_lock);
1905 /* check whether both sides are closing ... */
1906 final = !tty->count && !(o_tty && o_tty->count);
1908 tty_unlock_slave(o_tty);
1911 /* At this point, the tty->count == 0 should ensure a dead tty
1912 cannot be re-opened by a racing opener */
1917 tty_debug_hangup(tty, "final close\n");
1919 * Ask the line discipline code to release its structures
1921 tty_ldisc_release(tty);
1923 /* Wait for pending work before tty destruction commmences */
1924 tty_flush_works(tty);
1926 tty_debug_hangup(tty, "freeing structure...\n");
1928 * The release_tty function takes care of the details of clearing
1929 * the slots and preserving the termios structure. The tty_unlock_pair
1930 * should be safe as we keep a kref while the tty is locked (so the
1931 * unlock never unlocks a freed tty).
1933 mutex_lock(&tty_mutex);
1934 release_tty(tty, idx);
1935 mutex_unlock(&tty_mutex);
1941 * tty_open_current_tty - get locked tty of current task
1942 * @device: device number
1943 * @filp: file pointer to tty
1944 * @return: locked tty of the current task iff @device is /dev/tty
1946 * Performs a re-open of the current task's controlling tty.
1948 * We cannot return driver and index like for the other nodes because
1949 * devpts will not work then. It expects inodes to be from devpts FS.
1951 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1953 struct tty_struct *tty;
1956 if (device != MKDEV(TTYAUX_MAJOR, 0))
1959 tty = get_current_tty();
1961 return ERR_PTR(-ENXIO);
1963 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1966 tty_kref_put(tty); /* safe to drop the kref now */
1968 retval = tty_reopen(tty);
1971 tty = ERR_PTR(retval);
1977 * tty_lookup_driver - lookup a tty driver for a given device file
1978 * @device: device number
1979 * @filp: file pointer to tty
1980 * @noctty: set if the device should not become a controlling tty
1981 * @index: index for the device in the @return driver
1982 * @return: driver for this inode (with increased refcount)
1984 * If @return is not erroneous, the caller is responsible to decrement the
1985 * refcount by tty_driver_kref_put.
1987 * Locking: tty_mutex protects get_tty_driver
1989 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1990 int *noctty, int *index)
1992 struct tty_driver *driver;
1996 case MKDEV(TTY_MAJOR, 0): {
1997 extern struct tty_driver *console_driver;
1998 driver = tty_driver_kref_get(console_driver);
1999 *index = fg_console;
2004 case MKDEV(TTYAUX_MAJOR, 1): {
2005 struct tty_driver *console_driver = console_device(index);
2006 if (console_driver) {
2007 driver = tty_driver_kref_get(console_driver);
2009 /* Don't let /dev/console block */
2010 filp->f_flags |= O_NONBLOCK;
2015 return ERR_PTR(-ENODEV);
2018 driver = get_tty_driver(device, index);
2020 return ERR_PTR(-ENODEV);
2027 * tty_open - open a tty device
2028 * @inode: inode of device file
2029 * @filp: file pointer to tty
2031 * tty_open and tty_release keep up the tty count that contains the
2032 * number of opens done on a tty. We cannot use the inode-count, as
2033 * different inodes might point to the same tty.
2035 * Open-counting is needed for pty masters, as well as for keeping
2036 * track of serial lines: DTR is dropped when the last close happens.
2037 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2039 * The termios state of a pty is reset on first open so that
2040 * settings don't persist across reuse.
2042 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2043 * tty->count should protect the rest.
2044 * ->siglock protects ->signal/->sighand
2046 * Note: the tty_unlock/lock cases without a ref are only safe due to
2050 static int tty_open(struct inode *inode, struct file *filp)
2052 struct tty_struct *tty;
2054 struct tty_driver *driver = NULL;
2056 dev_t device = inode->i_rdev;
2057 unsigned saved_flags = filp->f_flags;
2059 nonseekable_open(inode, filp);
2062 retval = tty_alloc_file(filp);
2066 noctty = filp->f_flags & O_NOCTTY;
2070 tty = tty_open_current_tty(device, filp);
2072 mutex_lock(&tty_mutex);
2073 driver = tty_lookup_driver(device, filp, &noctty, &index);
2074 if (IS_ERR(driver)) {
2075 retval = PTR_ERR(driver);
2079 /* check whether we're reopening an existing tty */
2080 tty = tty_driver_lookup_tty(driver, inode, index);
2082 retval = PTR_ERR(tty);
2087 mutex_unlock(&tty_mutex);
2088 retval = tty_lock_interruptible(tty);
2089 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2091 if (retval == -EINTR)
2092 retval = -ERESTARTSYS;
2095 retval = tty_reopen(tty);
2098 tty = ERR_PTR(retval);
2100 } else { /* Returns with the tty_lock held for now */
2101 tty = tty_init_dev(driver, index);
2102 mutex_unlock(&tty_mutex);
2105 tty_driver_kref_put(driver);
2109 retval = PTR_ERR(tty);
2110 if (retval != -EAGAIN || signal_pending(current))
2112 tty_free_file(filp);
2117 tty_add_file(tty, filp);
2119 check_tty_count(tty, __func__);
2120 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2121 tty->driver->subtype == PTY_TYPE_MASTER)
2124 tty_debug_hangup(tty, "(tty count=%d)\n", tty->count);
2127 retval = tty->ops->open(tty, filp);
2130 filp->f_flags = saved_flags;
2133 tty_debug_hangup(tty, "error %d, releasing...\n", retval);
2135 tty_unlock(tty); /* need to call tty_release without BTM */
2136 tty_release(inode, filp);
2137 if (retval != -ERESTARTSYS)
2140 if (signal_pending(current))
2145 * Need to reset f_op in case a hangup happened.
2147 if (tty_hung_up_p(filp))
2148 filp->f_op = &tty_fops;
2151 clear_bit(TTY_HUPPED, &tty->flags);
2154 read_lock(&tasklist_lock);
2155 spin_lock_irq(¤t->sighand->siglock);
2157 current->signal->leader &&
2158 !current->signal->tty &&
2159 tty->session == NULL) {
2161 * Don't let a process that only has write access to the tty
2162 * obtain the privileges associated with having a tty as
2163 * controlling terminal (being able to reopen it with full
2164 * access through /dev/tty, being able to perform pushback).
2165 * Many distributions set the group of all ttys to "tty" and
2166 * grant write-only access to all terminals for setgid tty
2167 * binaries, which should not imply full privileges on all ttys.
2169 * This could theoretically break old code that performs open()
2170 * on a write-only file descriptor. In that case, it might be
2171 * necessary to also permit this if
2172 * inode_permission(inode, MAY_READ) == 0.
2174 if (filp->f_mode & FMODE_READ)
2175 __proc_set_tty(tty);
2177 spin_unlock_irq(¤t->sighand->siglock);
2178 read_unlock(&tasklist_lock);
2182 mutex_unlock(&tty_mutex);
2184 /* after locks to avoid deadlock */
2185 if (!IS_ERR_OR_NULL(driver))
2186 tty_driver_kref_put(driver);
2188 tty_free_file(filp);
2195 * tty_poll - check tty status
2196 * @filp: file being polled
2197 * @wait: poll wait structures to update
2199 * Call the line discipline polling method to obtain the poll
2200 * status of the device.
2202 * Locking: locks called line discipline but ldisc poll method
2203 * may be re-entered freely by other callers.
2206 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2208 struct tty_struct *tty = file_tty(filp);
2209 struct tty_ldisc *ld;
2212 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2215 ld = tty_ldisc_ref_wait(tty);
2217 ret = ld->ops->poll(tty, filp, wait);
2218 tty_ldisc_deref(ld);
2222 static int __tty_fasync(int fd, struct file *filp, int on)
2224 struct tty_struct *tty = file_tty(filp);
2225 struct tty_ldisc *ldisc;
2226 unsigned long flags;
2229 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2232 retval = fasync_helper(fd, filp, on, &tty->fasync);
2236 ldisc = tty_ldisc_ref(tty);
2238 if (ldisc->ops->fasync)
2239 ldisc->ops->fasync(tty, on);
2240 tty_ldisc_deref(ldisc);
2247 spin_lock_irqsave(&tty->ctrl_lock, flags);
2250 type = PIDTYPE_PGID;
2252 pid = task_pid(current);
2256 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2257 __f_setown(filp, pid, type, 0);
2265 static int tty_fasync(int fd, struct file *filp, int on)
2267 struct tty_struct *tty = file_tty(filp);
2271 retval = __tty_fasync(fd, filp, on);
2278 * tiocsti - fake input character
2279 * @tty: tty to fake input into
2280 * @p: pointer to character
2282 * Fake input to a tty device. Does the necessary locking and
2285 * FIXME: does not honour flow control ??
2288 * Called functions take tty_ldiscs_lock
2289 * current->signal->tty check is safe without locks
2292 static int tiocsti(struct tty_struct *tty, char __user *p)
2295 struct tty_ldisc *ld;
2297 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2299 if (get_user(ch, p))
2301 tty_audit_tiocsti(tty, ch);
2302 ld = tty_ldisc_ref_wait(tty);
2303 tty_buffer_lock_exclusive(tty->port);
2304 if (ld->ops->receive_buf)
2305 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2306 tty_buffer_unlock_exclusive(tty->port);
2307 tty_ldisc_deref(ld);
2312 * tiocgwinsz - implement window query ioctl
2314 * @arg: user buffer for result
2316 * Copies the kernel idea of the window size into the user buffer.
2318 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2322 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2326 mutex_lock(&tty->winsize_mutex);
2327 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2328 mutex_unlock(&tty->winsize_mutex);
2330 return err ? -EFAULT: 0;
2334 * tty_do_resize - resize event
2335 * @tty: tty being resized
2336 * @rows: rows (character)
2337 * @cols: cols (character)
2339 * Update the termios variables and send the necessary signals to
2340 * peform a terminal resize correctly
2343 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2348 mutex_lock(&tty->winsize_mutex);
2349 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2352 /* Signal the foreground process group */
2353 pgrp = tty_get_pgrp(tty);
2355 kill_pgrp(pgrp, SIGWINCH, 1);
2360 mutex_unlock(&tty->winsize_mutex);
2363 EXPORT_SYMBOL(tty_do_resize);
2366 * tiocswinsz - implement window size set ioctl
2367 * @tty; tty side of tty
2368 * @arg: user buffer for result
2370 * Copies the user idea of the window size to the kernel. Traditionally
2371 * this is just advisory information but for the Linux console it
2372 * actually has driver level meaning and triggers a VC resize.
2375 * Driver dependent. The default do_resize method takes the
2376 * tty termios mutex and ctrl_lock. The console takes its own lock
2377 * then calls into the default method.
2380 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2382 struct winsize tmp_ws;
2383 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2386 if (tty->ops->resize)
2387 return tty->ops->resize(tty, &tmp_ws);
2389 return tty_do_resize(tty, &tmp_ws);
2393 * tioccons - allow admin to move logical console
2394 * @file: the file to become console
2396 * Allow the administrator to move the redirected console device
2398 * Locking: uses redirect_lock to guard the redirect information
2401 static int tioccons(struct file *file)
2403 if (!capable(CAP_SYS_ADMIN))
2405 if (file->f_op->write == redirected_tty_write) {
2407 spin_lock(&redirect_lock);
2410 spin_unlock(&redirect_lock);
2415 spin_lock(&redirect_lock);
2417 spin_unlock(&redirect_lock);
2420 redirect = get_file(file);
2421 spin_unlock(&redirect_lock);
2426 * fionbio - non blocking ioctl
2427 * @file: file to set blocking value
2428 * @p: user parameter
2430 * Historical tty interfaces had a blocking control ioctl before
2431 * the generic functionality existed. This piece of history is preserved
2432 * in the expected tty API of posix OS's.
2434 * Locking: none, the open file handle ensures it won't go away.
2437 static int fionbio(struct file *file, int __user *p)
2441 if (get_user(nonblock, p))
2444 spin_lock(&file->f_lock);
2446 file->f_flags |= O_NONBLOCK;
2448 file->f_flags &= ~O_NONBLOCK;
2449 spin_unlock(&file->f_lock);
2454 * tiocsctty - set controlling tty
2455 * @tty: tty structure
2456 * @arg: user argument
2458 * This ioctl is used to manage job control. It permits a session
2459 * leader to set this tty as the controlling tty for the session.
2462 * Takes tty_lock() to serialize proc_set_tty() for this tty
2463 * Takes tasklist_lock internally to walk sessions
2464 * Takes ->siglock() when updating signal->tty
2467 static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2472 read_lock(&tasklist_lock);
2474 if (current->signal->leader && (task_session(current) == tty->session))
2478 * The process must be a session leader and
2479 * not have a controlling tty already.
2481 if (!current->signal->leader || current->signal->tty) {
2488 * This tty is already the controlling
2489 * tty for another session group!
2491 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2495 session_clear_tty(tty->session);
2502 /* See the comment in tty_open(). */
2503 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2510 read_unlock(&tasklist_lock);
2516 * tty_get_pgrp - return a ref counted pgrp pid
2519 * Returns a refcounted instance of the pid struct for the process
2520 * group controlling the tty.
2523 struct pid *tty_get_pgrp(struct tty_struct *tty)
2525 unsigned long flags;
2528 spin_lock_irqsave(&tty->ctrl_lock, flags);
2529 pgrp = get_pid(tty->pgrp);
2530 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2534 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2537 * This checks not only the pgrp, but falls back on the pid if no
2538 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2541 * The caller must hold rcu lock or the tasklist lock.
2543 static struct pid *session_of_pgrp(struct pid *pgrp)
2545 struct task_struct *p;
2546 struct pid *sid = NULL;
2548 p = pid_task(pgrp, PIDTYPE_PGID);
2550 p = pid_task(pgrp, PIDTYPE_PID);
2552 sid = task_session(p);
2558 * tiocgpgrp - get process group
2559 * @tty: tty passed by user
2560 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2563 * Obtain the process group of the tty. If there is no process group
2566 * Locking: none. Reference to current->signal->tty is safe.
2569 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2574 * (tty == real_tty) is a cheap way of
2575 * testing if the tty is NOT a master pty.
2577 if (tty == real_tty && current->signal->tty != real_tty)
2579 pid = tty_get_pgrp(real_tty);
2580 ret = put_user(pid_vnr(pid), p);
2586 * tiocspgrp - attempt to set process group
2587 * @tty: tty passed by user
2588 * @real_tty: tty side device matching tty passed by user
2591 * Set the process group of the tty to the session passed. Only
2592 * permitted where the tty session is our session.
2594 * Locking: RCU, ctrl lock
2597 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2601 int retval = tty_check_change(real_tty);
2608 if (get_user(pgrp_nr, p))
2613 spin_lock_irq(&real_tty->ctrl_lock);
2614 if (!current->signal->tty ||
2615 (current->signal->tty != real_tty) ||
2616 (real_tty->session != task_session(current))) {
2618 goto out_unlock_ctrl;
2621 pgrp = find_vpid(pgrp_nr);
2626 if (session_of_pgrp(pgrp) != task_session(current))
2629 put_pid(real_tty->pgrp);
2630 real_tty->pgrp = get_pid(pgrp);
2634 spin_unlock_irq(&real_tty->ctrl_lock);
2639 * tiocgsid - get session id
2640 * @tty: tty passed by user
2641 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2642 * @p: pointer to returned session id
2644 * Obtain the session id of the tty. If there is no session
2648 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2650 unsigned long flags;
2654 * (tty == real_tty) is a cheap way of
2655 * testing if the tty is NOT a master pty.
2657 if (tty == real_tty && current->signal->tty != real_tty)
2660 spin_lock_irqsave(&real_tty->ctrl_lock, flags);
2661 if (!real_tty->session)
2663 sid = pid_vnr(real_tty->session);
2664 spin_unlock_irqrestore(&real_tty->ctrl_lock, flags);
2666 return put_user(sid, p);
2669 spin_unlock_irqrestore(&real_tty->ctrl_lock, flags);
2674 * tiocsetd - set line discipline
2676 * @p: pointer to user data
2678 * Set the line discipline according to user request.
2680 * Locking: see tty_set_ldisc, this function is just a helper
2683 static int tiocsetd(struct tty_struct *tty, int __user *p)
2688 if (get_user(ldisc, p))
2691 ret = tty_set_ldisc(tty, ldisc);
2697 * tiocgetd - get line discipline
2699 * @p: pointer to user data
2701 * Retrieves the line discipline id directly from the ldisc.
2703 * Locking: waits for ldisc reference (in case the line discipline
2704 * is changing or the tty is being hungup)
2707 static int tiocgetd(struct tty_struct *tty, int __user *p)
2709 struct tty_ldisc *ld;
2712 ld = tty_ldisc_ref_wait(tty);
2713 ret = put_user(ld->ops->num, p);
2714 tty_ldisc_deref(ld);
2719 * send_break - performed time break
2720 * @tty: device to break on
2721 * @duration: timeout in mS
2723 * Perform a timed break on hardware that lacks its own driver level
2724 * timed break functionality.
2727 * atomic_write_lock serializes
2731 static int send_break(struct tty_struct *tty, unsigned int duration)
2735 if (tty->ops->break_ctl == NULL)
2738 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2739 retval = tty->ops->break_ctl(tty, duration);
2741 /* Do the work ourselves */
2742 if (tty_write_lock(tty, 0) < 0)
2744 retval = tty->ops->break_ctl(tty, -1);
2747 if (!signal_pending(current))
2748 msleep_interruptible(duration);
2749 retval = tty->ops->break_ctl(tty, 0);
2751 tty_write_unlock(tty);
2752 if (signal_pending(current))
2759 * tty_tiocmget - get modem status
2761 * @file: user file pointer
2762 * @p: pointer to result
2764 * Obtain the modem status bits from the tty driver if the feature
2765 * is supported. Return -ENOTTY if it is not available.
2767 * Locking: none (up to the driver)
2770 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2772 int retval = -ENOTTY;
2774 if (tty->ops->tiocmget) {
2775 retval = tty->ops->tiocmget(tty);
2778 retval = put_user(retval, p);
2784 * tty_tiocmset - set modem status
2786 * @cmd: command - clear bits, set bits or set all
2787 * @p: pointer to desired bits
2789 * Set the modem status bits from the tty driver if the feature
2790 * is supported. Return -ENOTTY if it is not available.
2792 * Locking: none (up to the driver)
2795 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2799 unsigned int set, clear, val;
2801 if (tty->ops->tiocmset == NULL)
2804 retval = get_user(val, p);
2820 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2821 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2822 return tty->ops->tiocmset(tty, set, clear);
2825 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2827 int retval = -EINVAL;
2828 struct serial_icounter_struct icount;
2829 memset(&icount, 0, sizeof(icount));
2830 if (tty->ops->get_icount)
2831 retval = tty->ops->get_icount(tty, &icount);
2834 if (copy_to_user(arg, &icount, sizeof(icount)))
2839 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2841 static DEFINE_RATELIMIT_STATE(depr_flags,
2842 DEFAULT_RATELIMIT_INTERVAL,
2843 DEFAULT_RATELIMIT_BURST);
2844 char comm[TASK_COMM_LEN];
2847 if (get_user(flags, &ss->flags))
2850 flags &= ASYNC_DEPRECATED;
2852 if (flags && __ratelimit(&depr_flags))
2853 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2854 __func__, get_task_comm(comm, current), flags);
2858 * if pty, return the slave side (real_tty)
2859 * otherwise, return self
2861 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2863 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2864 tty->driver->subtype == PTY_TYPE_MASTER)
2870 * Split this up, as gcc can choke on it otherwise..
2872 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2874 struct tty_struct *tty = file_tty(file);
2875 struct tty_struct *real_tty;
2876 void __user *p = (void __user *)arg;
2878 struct tty_ldisc *ld;
2880 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2883 real_tty = tty_pair_get_tty(tty);
2886 * Factor out some common prep work
2894 retval = tty_check_change(tty);
2897 if (cmd != TIOCCBRK) {
2898 tty_wait_until_sent(tty, 0);
2899 if (signal_pending(current))
2910 return tiocsti(tty, p);
2912 return tiocgwinsz(real_tty, p);
2914 return tiocswinsz(real_tty, p);
2916 return real_tty != tty ? -EINVAL : tioccons(file);
2918 return fionbio(file, p);
2920 set_bit(TTY_EXCLUSIVE, &tty->flags);
2923 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2927 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2928 return put_user(excl, (int __user *)p);
2931 if (current->signal->tty != tty)
2936 return tiocsctty(tty, file, arg);
2938 return tiocgpgrp(tty, real_tty, p);
2940 return tiocspgrp(tty, real_tty, p);
2942 return tiocgsid(tty, real_tty, p);
2944 return tiocgetd(tty, p);
2946 return tiocsetd(tty, p);
2948 if (!capable(CAP_SYS_ADMIN))
2954 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2955 return put_user(ret, (unsigned int __user *)p);
2960 case TIOCSBRK: /* Turn break on, unconditionally */
2961 if (tty->ops->break_ctl)
2962 return tty->ops->break_ctl(tty, -1);
2964 case TIOCCBRK: /* Turn break off, unconditionally */
2965 if (tty->ops->break_ctl)
2966 return tty->ops->break_ctl(tty, 0);
2968 case TCSBRK: /* SVID version: non-zero arg --> no break */
2969 /* non-zero arg means wait for all output data
2970 * to be sent (performed above) but don't send break.
2971 * This is used by the tcdrain() termios function.
2974 return send_break(tty, 250);
2976 case TCSBRKP: /* support for POSIX tcsendbreak() */
2977 return send_break(tty, arg ? arg*100 : 250);
2980 return tty_tiocmget(tty, p);
2984 return tty_tiocmset(tty, cmd, p);
2986 retval = tty_tiocgicount(tty, p);
2987 /* For the moment allow fall through to the old method */
2988 if (retval != -EINVAL)
2995 /* flush tty buffer and allow ldisc to process ioctl */
2996 tty_buffer_flush(tty, NULL);
3001 tty_warn_deprecated_flags(p);
3004 if (tty->ops->ioctl) {
3005 retval = tty->ops->ioctl(tty, cmd, arg);
3006 if (retval != -ENOIOCTLCMD)
3009 ld = tty_ldisc_ref_wait(tty);
3011 if (ld->ops->ioctl) {
3012 retval = ld->ops->ioctl(tty, file, cmd, arg);
3013 if (retval == -ENOIOCTLCMD)
3016 tty_ldisc_deref(ld);
3020 #ifdef CONFIG_COMPAT
3021 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
3024 struct tty_struct *tty = file_tty(file);
3025 struct tty_ldisc *ld;
3026 int retval = -ENOIOCTLCMD;
3028 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
3031 if (tty->ops->compat_ioctl) {
3032 retval = tty->ops->compat_ioctl(tty, cmd, arg);
3033 if (retval != -ENOIOCTLCMD)
3037 ld = tty_ldisc_ref_wait(tty);
3038 if (ld->ops->compat_ioctl)
3039 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
3041 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
3042 tty_ldisc_deref(ld);
3048 static int this_tty(const void *t, struct file *file, unsigned fd)
3050 if (likely(file->f_op->read != tty_read))
3052 return file_tty(file) != t ? 0 : fd + 1;
3056 * This implements the "Secure Attention Key" --- the idea is to
3057 * prevent trojan horses by killing all processes associated with this
3058 * tty when the user hits the "Secure Attention Key". Required for
3059 * super-paranoid applications --- see the Orange Book for more details.
3061 * This code could be nicer; ideally it should send a HUP, wait a few
3062 * seconds, then send a INT, and then a KILL signal. But you then
3063 * have to coordinate with the init process, since all processes associated
3064 * with the current tty must be dead before the new getty is allowed
3067 * Now, if it would be correct ;-/ The current code has a nasty hole -
3068 * it doesn't catch files in flight. We may send the descriptor to ourselves
3069 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3071 * Nasty bug: do_SAK is being called in interrupt context. This can
3072 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3074 void __do_SAK(struct tty_struct *tty)
3079 struct task_struct *g, *p;
3080 struct pid *session;
3082 unsigned long flags;
3087 spin_lock_irqsave(&tty->ctrl_lock, flags);
3088 session = get_pid(tty->session);
3089 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3091 tty_ldisc_flush(tty);
3093 tty_driver_flush_buffer(tty);
3095 read_lock(&tasklist_lock);
3096 /* Kill the entire session */
3097 do_each_pid_task(session, PIDTYPE_SID, p) {
3098 printk(KERN_NOTICE "SAK: killed process %d"
3099 " (%s): task_session(p)==tty->session\n",
3100 task_pid_nr(p), p->comm);
3101 send_sig(SIGKILL, p, 1);
3102 } while_each_pid_task(session, PIDTYPE_SID, p);
3103 /* Now kill any processes that happen to have the
3106 do_each_thread(g, p) {
3107 if (p->signal->tty == tty) {
3108 printk(KERN_NOTICE "SAK: killed process %d"
3109 " (%s): task_session(p)==tty->session\n",
3110 task_pid_nr(p), p->comm);
3111 send_sig(SIGKILL, p, 1);
3115 i = iterate_fd(p->files, 0, this_tty, tty);
3117 printk(KERN_NOTICE "SAK: killed process %d"
3118 " (%s): fd#%d opened to the tty\n",
3119 task_pid_nr(p), p->comm, i - 1);
3120 force_sig(SIGKILL, p);
3123 } while_each_thread(g, p);
3124 read_unlock(&tasklist_lock);
3129 static void do_SAK_work(struct work_struct *work)
3131 struct tty_struct *tty =
3132 container_of(work, struct tty_struct, SAK_work);
3137 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3138 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3139 * the values which we write to it will be identical to the values which it
3140 * already has. --akpm
3142 void do_SAK(struct tty_struct *tty)
3146 schedule_work(&tty->SAK_work);
3149 EXPORT_SYMBOL(do_SAK);
3151 static int dev_match_devt(struct device *dev, const void *data)
3153 const dev_t *devt = data;
3154 return dev->devt == *devt;
3157 /* Must put_device() after it's unused! */
3158 static struct device *tty_get_device(struct tty_struct *tty)
3160 dev_t devt = tty_devnum(tty);
3161 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3168 * This subroutine allocates and initializes a tty structure.
3170 * Locking: none - tty in question is not exposed at this point
3173 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3175 struct tty_struct *tty;
3177 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3181 kref_init(&tty->kref);
3182 tty->magic = TTY_MAGIC;
3183 if (tty_ldisc_init(tty)) {
3187 tty->session = NULL;
3189 mutex_init(&tty->legacy_mutex);
3190 mutex_init(&tty->throttle_mutex);
3191 init_rwsem(&tty->termios_rwsem);
3192 mutex_init(&tty->winsize_mutex);
3193 init_ldsem(&tty->ldisc_sem);
3194 init_waitqueue_head(&tty->write_wait);
3195 init_waitqueue_head(&tty->read_wait);
3196 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3197 mutex_init(&tty->atomic_write_lock);
3198 spin_lock_init(&tty->ctrl_lock);
3199 spin_lock_init(&tty->flow_lock);
3200 INIT_LIST_HEAD(&tty->tty_files);
3201 INIT_WORK(&tty->SAK_work, do_SAK_work);
3203 tty->driver = driver;
3204 tty->ops = driver->ops;
3206 tty_line_name(driver, idx, tty->name);
3207 tty->dev = tty_get_device(tty);
3213 * deinitialize_tty_struct
3214 * @tty: tty to deinitialize
3216 * This subroutine deinitializes a tty structure that has been newly
3217 * allocated but tty_release cannot be called on that yet.
3219 * Locking: none - tty in question must not be exposed at this point
3221 void deinitialize_tty_struct(struct tty_struct *tty)
3223 tty_ldisc_deinit(tty);
3227 * tty_put_char - write one character to a tty
3231 * Write one byte to the tty using the provided put_char method
3232 * if present. Returns the number of characters successfully output.
3234 * Note: the specific put_char operation in the driver layer may go
3235 * away soon. Don't call it directly, use this method
3238 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3240 if (tty->ops->put_char)
3241 return tty->ops->put_char(tty, ch);
3242 return tty->ops->write(tty, &ch, 1);
3244 EXPORT_SYMBOL_GPL(tty_put_char);
3246 struct class *tty_class;
3248 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3249 unsigned int index, unsigned int count)
3253 /* init here, since reused cdevs cause crashes */
3254 driver->cdevs[index] = cdev_alloc();
3255 if (!driver->cdevs[index])
3257 driver->cdevs[index]->ops = &tty_fops;
3258 driver->cdevs[index]->owner = driver->owner;
3259 err = cdev_add(driver->cdevs[index], dev, count);
3261 kobject_put(&driver->cdevs[index]->kobj);
3266 * tty_register_device - register a tty device
3267 * @driver: the tty driver that describes the tty device
3268 * @index: the index in the tty driver for this tty device
3269 * @device: a struct device that is associated with this tty device.
3270 * This field is optional, if there is no known struct device
3271 * for this tty device it can be set to NULL safely.
3273 * Returns a pointer to the struct device for this tty device
3274 * (or ERR_PTR(-EFOO) on error).
3276 * This call is required to be made to register an individual tty device
3277 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3278 * that bit is not set, this function should not be called by a tty
3284 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3285 struct device *device)
3287 return tty_register_device_attr(driver, index, device, NULL, NULL);
3289 EXPORT_SYMBOL(tty_register_device);
3291 static void tty_device_create_release(struct device *dev)
3293 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3298 * tty_register_device_attr - register a tty device
3299 * @driver: the tty driver that describes the tty device
3300 * @index: the index in the tty driver for this tty device
3301 * @device: a struct device that is associated with this tty device.
3302 * This field is optional, if there is no known struct device
3303 * for this tty device it can be set to NULL safely.
3304 * @drvdata: Driver data to be set to device.
3305 * @attr_grp: Attribute group to be set on device.
3307 * Returns a pointer to the struct device for this tty device
3308 * (or ERR_PTR(-EFOO) on error).
3310 * This call is required to be made to register an individual tty device
3311 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3312 * that bit is not set, this function should not be called by a tty
3317 struct device *tty_register_device_attr(struct tty_driver *driver,
3318 unsigned index, struct device *device,
3320 const struct attribute_group **attr_grp)
3323 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3324 struct device *dev = NULL;
3325 int retval = -ENODEV;
3328 if (index >= driver->num) {
3329 printk(KERN_ERR "Attempt to register invalid tty line number "
3331 return ERR_PTR(-EINVAL);
3334 if (driver->type == TTY_DRIVER_TYPE_PTY)
3335 pty_line_name(driver, index, name);
3337 tty_line_name(driver, index, name);
3339 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3340 retval = tty_cdev_add(driver, devt, index, 1);
3346 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3353 dev->class = tty_class;
3354 dev->parent = device;
3355 dev->release = tty_device_create_release;
3356 dev_set_name(dev, "%s", name);
3357 dev->groups = attr_grp;
3358 dev_set_drvdata(dev, drvdata);
3360 retval = device_register(dev);
3369 cdev_del(driver->cdevs[index]);
3370 driver->cdevs[index] = NULL;
3372 return ERR_PTR(retval);
3374 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3377 * tty_unregister_device - unregister a tty device
3378 * @driver: the tty driver that describes the tty device
3379 * @index: the index in the tty driver for this tty device
3381 * If a tty device is registered with a call to tty_register_device() then
3382 * this function must be called when the tty device is gone.
3387 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3389 device_destroy(tty_class,
3390 MKDEV(driver->major, driver->minor_start) + index);
3391 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3392 cdev_del(driver->cdevs[index]);
3393 driver->cdevs[index] = NULL;
3396 EXPORT_SYMBOL(tty_unregister_device);
3399 * __tty_alloc_driver -- allocate tty driver
3400 * @lines: count of lines this driver can handle at most
3401 * @owner: module which is repsonsible for this driver
3402 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3404 * This should not be called directly, some of the provided macros should be
3405 * used instead. Use IS_ERR and friends on @retval.
3407 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3408 unsigned long flags)
3410 struct tty_driver *driver;
3411 unsigned int cdevs = 1;
3414 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3415 return ERR_PTR(-EINVAL);
3417 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3419 return ERR_PTR(-ENOMEM);
3421 kref_init(&driver->kref);
3422 driver->magic = TTY_DRIVER_MAGIC;
3423 driver->num = lines;
3424 driver->owner = owner;
3425 driver->flags = flags;
3427 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3428 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3430 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3432 if (!driver->ttys || !driver->termios) {
3438 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3439 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3441 if (!driver->ports) {
3448 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3449 if (!driver->cdevs) {
3456 kfree(driver->ports);
3457 kfree(driver->ttys);
3458 kfree(driver->termios);
3459 kfree(driver->cdevs);
3461 return ERR_PTR(err);
3463 EXPORT_SYMBOL(__tty_alloc_driver);
3465 static void destruct_tty_driver(struct kref *kref)
3467 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3469 struct ktermios *tp;
3471 if (driver->flags & TTY_DRIVER_INSTALLED) {
3473 * Free the termios and termios_locked structures because
3474 * we don't want to get memory leaks when modular tty
3475 * drivers are removed from the kernel.
3477 for (i = 0; i < driver->num; i++) {
3478 tp = driver->termios[i];
3480 driver->termios[i] = NULL;
3483 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3484 tty_unregister_device(driver, i);
3486 proc_tty_unregister_driver(driver);
3487 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3488 cdev_del(driver->cdevs[0]);
3490 kfree(driver->cdevs);
3491 kfree(driver->ports);
3492 kfree(driver->termios);
3493 kfree(driver->ttys);
3497 void tty_driver_kref_put(struct tty_driver *driver)
3499 kref_put(&driver->kref, destruct_tty_driver);
3501 EXPORT_SYMBOL(tty_driver_kref_put);
3503 void tty_set_operations(struct tty_driver *driver,
3504 const struct tty_operations *op)
3508 EXPORT_SYMBOL(tty_set_operations);
3510 void put_tty_driver(struct tty_driver *d)
3512 tty_driver_kref_put(d);
3514 EXPORT_SYMBOL(put_tty_driver);
3517 * Called by a tty driver to register itself.
3519 int tty_register_driver(struct tty_driver *driver)
3526 if (!driver->major) {
3527 error = alloc_chrdev_region(&dev, driver->minor_start,
3528 driver->num, driver->name);
3530 driver->major = MAJOR(dev);
3531 driver->minor_start = MINOR(dev);
3534 dev = MKDEV(driver->major, driver->minor_start);
3535 error = register_chrdev_region(dev, driver->num, driver->name);
3540 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3541 error = tty_cdev_add(driver, dev, 0, driver->num);
3543 goto err_unreg_char;
3546 mutex_lock(&tty_mutex);
3547 list_add(&driver->tty_drivers, &tty_drivers);
3548 mutex_unlock(&tty_mutex);
3550 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3551 for (i = 0; i < driver->num; i++) {
3552 d = tty_register_device(driver, i, NULL);
3555 goto err_unreg_devs;
3559 proc_tty_register_driver(driver);
3560 driver->flags |= TTY_DRIVER_INSTALLED;
3564 for (i--; i >= 0; i--)
3565 tty_unregister_device(driver, i);
3567 mutex_lock(&tty_mutex);
3568 list_del(&driver->tty_drivers);
3569 mutex_unlock(&tty_mutex);
3572 unregister_chrdev_region(dev, driver->num);
3576 EXPORT_SYMBOL(tty_register_driver);
3579 * Called by a tty driver to unregister itself.
3581 int tty_unregister_driver(struct tty_driver *driver)
3585 if (driver->refcount)
3588 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3590 mutex_lock(&tty_mutex);
3591 list_del(&driver->tty_drivers);
3592 mutex_unlock(&tty_mutex);
3596 EXPORT_SYMBOL(tty_unregister_driver);
3598 dev_t tty_devnum(struct tty_struct *tty)
3600 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3602 EXPORT_SYMBOL(tty_devnum);
3604 void tty_default_fops(struct file_operations *fops)
3610 * Initialize the console device. This is called *early*, so
3611 * we can't necessarily depend on lots of kernel help here.
3612 * Just do some early initializations, and do the complex setup
3615 void __init console_init(void)
3619 /* Setup the default TTY line discipline. */
3623 * set up the console device so that later boot sequences can
3624 * inform about problems etc..
3626 call = __con_initcall_start;
3627 while (call < __con_initcall_end) {
3633 static char *tty_devnode(struct device *dev, umode_t *mode)
3637 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3638 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3643 static int __init tty_class_init(void)
3645 tty_class = class_create(THIS_MODULE, "tty");
3646 if (IS_ERR(tty_class))
3647 return PTR_ERR(tty_class);
3648 tty_class->devnode = tty_devnode;
3652 postcore_initcall(tty_class_init);
3654 /* 3/2004 jmc: why do these devices exist? */
3655 static struct cdev tty_cdev, console_cdev;
3657 static ssize_t show_cons_active(struct device *dev,
3658 struct device_attribute *attr, char *buf)
3660 struct console *cs[16];
3666 for_each_console(c) {
3671 if ((c->flags & CON_ENABLED) == 0)
3674 if (i >= ARRAY_SIZE(cs))
3678 int index = cs[i]->index;
3679 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3681 /* don't resolve tty0 as some programs depend on it */
3682 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3683 count += tty_line_name(drv, index, buf + count);
3685 count += sprintf(buf + count, "%s%d",
3686 cs[i]->name, cs[i]->index);
3688 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3694 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3696 static struct attribute *cons_dev_attrs[] = {
3697 &dev_attr_active.attr,
3701 ATTRIBUTE_GROUPS(cons_dev);
3703 static struct device *consdev;
3705 void console_sysfs_notify(void)
3708 sysfs_notify(&consdev->kobj, NULL, "active");
3712 * Ok, now we can initialize the rest of the tty devices and can count
3713 * on memory allocations, interrupts etc..
3715 int __init tty_init(void)
3718 cdev_init(&tty_cdev, &tty_fops);
3719 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3720 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3721 panic("Couldn't register /dev/tty driver\n");
3722 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3724 cdev_init(&console_cdev, &console_fops);
3725 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3726 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3727 panic("Couldn't register /dev/console driver\n");
3728 consdev = device_create_with_groups(tty_class, NULL,
3729 MKDEV(TTYAUX_MAJOR, 1), NULL,
3730 cons_dev_groups, "console");
3731 if (IS_ERR(consdev))
3735 vty_init(&console_fops);