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 const char *tty_driver_name(const struct tty_struct *tty)
261 if (!tty || !tty->driver)
263 return tty->driver->name;
266 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
269 #ifdef TTY_PARANOIA_CHECK
271 pr_warn("(%d:%d): %s: NULL tty\n",
272 imajor(inode), iminor(inode), routine);
275 if (tty->magic != TTY_MAGIC) {
276 pr_warn("(%d:%d): %s: bad magic number\n",
277 imajor(inode), iminor(inode), routine);
284 /* Caller must hold tty_lock */
285 static int check_tty_count(struct tty_struct *tty, const char *routine)
287 #ifdef CHECK_TTY_COUNT
291 spin_lock(&tty_files_lock);
292 list_for_each(p, &tty->tty_files) {
295 spin_unlock(&tty_files_lock);
296 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
297 tty->driver->subtype == PTY_TYPE_SLAVE &&
298 tty->link && tty->link->count)
300 if (tty->count != count) {
301 tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
302 routine, tty->count, count);
310 * get_tty_driver - find device of a tty
311 * @dev_t: device identifier
312 * @index: returns the index of the tty
314 * This routine returns a tty driver structure, given a device number
315 * and also passes back the index number.
317 * Locking: caller must hold tty_mutex
320 static struct tty_driver *get_tty_driver(dev_t device, int *index)
322 struct tty_driver *p;
324 list_for_each_entry(p, &tty_drivers, tty_drivers) {
325 dev_t base = MKDEV(p->major, p->minor_start);
326 if (device < base || device >= base + p->num)
328 *index = device - base;
329 return tty_driver_kref_get(p);
334 #ifdef CONFIG_CONSOLE_POLL
337 * tty_find_polling_driver - find device of a polled tty
338 * @name: name string to match
339 * @line: pointer to resulting tty line nr
341 * This routine returns a tty driver structure, given a name
342 * and the condition that the tty driver is capable of polled
345 struct tty_driver *tty_find_polling_driver(char *name, int *line)
347 struct tty_driver *p, *res = NULL;
352 for (str = name; *str; str++)
353 if ((*str >= '0' && *str <= '9') || *str == ',')
359 tty_line = simple_strtoul(str, &str, 10);
361 mutex_lock(&tty_mutex);
362 /* Search through the tty devices to look for a match */
363 list_for_each_entry(p, &tty_drivers, tty_drivers) {
364 if (strncmp(name, p->name, len) != 0)
372 if (tty_line >= 0 && tty_line < p->num && p->ops &&
373 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
374 res = tty_driver_kref_get(p);
379 mutex_unlock(&tty_mutex);
383 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
387 * tty_check_change - check for POSIX terminal changes
390 * If we try to write to, or set the state of, a terminal and we're
391 * not in the foreground, send a SIGTTOU. If the signal is blocked or
392 * ignored, go ahead and perform the operation. (POSIX 7.2)
397 int __tty_check_change(struct tty_struct *tty, int sig)
400 struct pid *pgrp, *tty_pgrp;
403 if (current->signal->tty != tty)
407 pgrp = task_pgrp(current);
409 spin_lock_irqsave(&tty->ctrl_lock, flags);
410 tty_pgrp = tty->pgrp;
411 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
413 if (tty_pgrp && pgrp != tty->pgrp) {
414 if (is_ignored(sig)) {
417 } else if (is_current_pgrp_orphaned())
420 kill_pgrp(pgrp, sig, 1);
421 set_thread_flag(TIF_SIGPENDING);
428 tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);
433 int tty_check_change(struct tty_struct *tty)
435 return __tty_check_change(tty, SIGTTOU);
437 EXPORT_SYMBOL(tty_check_change);
439 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
440 size_t count, loff_t *ppos)
445 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
446 size_t count, loff_t *ppos)
451 /* No kernel lock held - none needed ;) */
452 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
454 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
457 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
460 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
463 static long hung_up_tty_compat_ioctl(struct file *file,
464 unsigned int cmd, unsigned long arg)
466 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
469 static const struct file_operations tty_fops = {
474 .unlocked_ioctl = tty_ioctl,
475 .compat_ioctl = tty_compat_ioctl,
477 .release = tty_release,
478 .fasync = tty_fasync,
481 static const struct file_operations console_fops = {
484 .write = redirected_tty_write,
486 .unlocked_ioctl = tty_ioctl,
487 .compat_ioctl = tty_compat_ioctl,
489 .release = tty_release,
490 .fasync = tty_fasync,
493 static const struct file_operations hung_up_tty_fops = {
495 .read = hung_up_tty_read,
496 .write = hung_up_tty_write,
497 .poll = hung_up_tty_poll,
498 .unlocked_ioctl = hung_up_tty_ioctl,
499 .compat_ioctl = hung_up_tty_compat_ioctl,
500 .release = tty_release,
503 static DEFINE_SPINLOCK(redirect_lock);
504 static struct file *redirect;
507 void proc_clear_tty(struct task_struct *p)
510 struct tty_struct *tty;
511 spin_lock_irqsave(&p->sighand->siglock, flags);
512 tty = p->signal->tty;
513 p->signal->tty = NULL;
514 spin_unlock_irqrestore(&p->sighand->siglock, flags);
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 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
541 tty->session = get_pid(task_session(current));
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)) {
707 /* inuse_filps is protected by the single tty lock,
708 this really needs to change if we want to flush the
709 workqueue with the lock held */
710 check_tty_count(tty, "tty_hangup");
712 spin_lock(&tty_files_lock);
713 /* This breaks for file handles being sent over AF_UNIX sockets ? */
714 list_for_each_entry(priv, &tty->tty_files, list) {
716 if (filp->f_op->write == redirected_tty_write)
718 if (filp->f_op->write != tty_write)
721 __tty_fasync(-1, filp, 0); /* can't block */
722 filp->f_op = &hung_up_tty_fops;
724 spin_unlock(&tty_files_lock);
726 refs = tty_signal_session_leader(tty, exit_session);
727 /* Account for the p->signal references we killed */
731 tty_ldisc_hangup(tty);
733 spin_lock_irq(&tty->ctrl_lock);
734 clear_bit(TTY_THROTTLED, &tty->flags);
735 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
736 put_pid(tty->session);
740 tty->ctrl_status = 0;
741 spin_unlock_irq(&tty->ctrl_lock);
744 * If one of the devices matches a console pointer, we
745 * cannot just call hangup() because that will cause
746 * tty->count and state->count to go out of sync.
747 * So we just call close() the right number of times.
751 for (n = 0; n < closecount; n++)
752 tty->ops->close(tty, cons_filp);
753 } else if (tty->ops->hangup)
754 tty->ops->hangup(tty);
756 * We don't want to have driver/ldisc interactions beyond
757 * the ones we did here. The driver layer expects no
758 * calls after ->hangup() from the ldisc side. However we
759 * can't yet guarantee all that.
761 set_bit(TTY_HUPPED, &tty->flags);
768 static void do_tty_hangup(struct work_struct *work)
770 struct tty_struct *tty =
771 container_of(work, struct tty_struct, hangup_work);
773 __tty_hangup(tty, 0);
777 * tty_hangup - trigger a hangup event
778 * @tty: tty to hangup
780 * A carrier loss (virtual or otherwise) has occurred on this like
781 * schedule a hangup sequence to run after this event.
784 void tty_hangup(struct tty_struct *tty)
786 tty_debug_hangup(tty, "hangup\n");
787 schedule_work(&tty->hangup_work);
790 EXPORT_SYMBOL(tty_hangup);
793 * tty_vhangup - process vhangup
794 * @tty: tty to hangup
796 * The user has asked via system call for the terminal to be hung up.
797 * We do this synchronously so that when the syscall returns the process
798 * is complete. That guarantee is necessary for security reasons.
801 void tty_vhangup(struct tty_struct *tty)
803 tty_debug_hangup(tty, "vhangup\n");
804 __tty_hangup(tty, 0);
807 EXPORT_SYMBOL(tty_vhangup);
811 * tty_vhangup_self - process vhangup for own ctty
813 * Perform a vhangup on the current controlling tty
816 void tty_vhangup_self(void)
818 struct tty_struct *tty;
820 tty = get_current_tty();
828 * tty_vhangup_session - hangup session leader exit
829 * @tty: tty to hangup
831 * The session leader is exiting and hanging up its controlling terminal.
832 * Every process in the foreground process group is signalled SIGHUP.
834 * We do this synchronously so that when the syscall returns the process
835 * is complete. That guarantee is necessary for security reasons.
838 static void tty_vhangup_session(struct tty_struct *tty)
840 tty_debug_hangup(tty, "session hangup\n");
841 __tty_hangup(tty, 1);
845 * tty_hung_up_p - was tty hung up
846 * @filp: file pointer of tty
848 * Return true if the tty has been subject to a vhangup or a carrier
852 int tty_hung_up_p(struct file *filp)
854 return (filp->f_op == &hung_up_tty_fops);
857 EXPORT_SYMBOL(tty_hung_up_p);
860 * disassociate_ctty - disconnect controlling tty
861 * @on_exit: true if exiting so need to "hang up" the session
863 * This function is typically called only by the session leader, when
864 * it wants to disassociate itself from its controlling tty.
866 * It performs the following functions:
867 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
868 * (2) Clears the tty from being controlling the session
869 * (3) Clears the controlling tty for all processes in the
872 * The argument on_exit is set to 1 if called when a process is
873 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
876 * BTM is taken for hysterical raisins, and held when
877 * called from no_tty().
878 * tty_mutex is taken to protect tty
879 * ->siglock is taken to protect ->signal/->sighand
880 * tasklist_lock is taken to walk process list for sessions
881 * ->siglock is taken to protect ->signal/->sighand
884 void disassociate_ctty(int on_exit)
886 struct tty_struct *tty;
888 if (!current->signal->leader)
891 tty = get_current_tty();
893 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
894 tty_vhangup_session(tty);
896 struct pid *tty_pgrp = tty_get_pgrp(tty);
898 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
900 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
906 } else if (on_exit) {
907 struct pid *old_pgrp;
908 spin_lock_irq(¤t->sighand->siglock);
909 old_pgrp = current->signal->tty_old_pgrp;
910 current->signal->tty_old_pgrp = NULL;
911 spin_unlock_irq(¤t->sighand->siglock);
913 kill_pgrp(old_pgrp, SIGHUP, on_exit);
914 kill_pgrp(old_pgrp, SIGCONT, on_exit);
920 spin_lock_irq(¤t->sighand->siglock);
921 put_pid(current->signal->tty_old_pgrp);
922 current->signal->tty_old_pgrp = NULL;
924 tty = tty_kref_get(current->signal->tty);
927 spin_lock_irqsave(&tty->ctrl_lock, flags);
928 put_pid(tty->session);
932 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
935 tty_debug_hangup(tty, "no current tty\n");
937 spin_unlock_irq(¤t->sighand->siglock);
938 /* Now clear signal->tty under the lock */
939 read_lock(&tasklist_lock);
940 session_clear_tty(task_session(current));
941 read_unlock(&tasklist_lock);
946 * no_tty - Ensure the current process does not have a controlling tty
950 /* FIXME: Review locking here. The tty_lock never covered any race
951 between a new association and proc_clear_tty but possible we need
952 to protect against this anyway */
953 struct task_struct *tsk = current;
954 disassociate_ctty(0);
960 * stop_tty - propagate flow control
963 * Perform flow control to the driver. May be called
964 * on an already stopped device and will not re-call the driver
967 * This functionality is used by both the line disciplines for
968 * halting incoming flow and by the driver. It may therefore be
969 * called from any context, may be under the tty atomic_write_lock
976 void __stop_tty(struct tty_struct *tty)
985 void stop_tty(struct tty_struct *tty)
989 spin_lock_irqsave(&tty->flow_lock, flags);
991 spin_unlock_irqrestore(&tty->flow_lock, flags);
993 EXPORT_SYMBOL(stop_tty);
996 * start_tty - propagate flow control
999 * Start a tty that has been stopped if at all possible. If this
1000 * tty was previous stopped and is now being started, the driver
1001 * start method is invoked and the line discipline woken.
1007 void __start_tty(struct tty_struct *tty)
1009 if (!tty->stopped || tty->flow_stopped)
1012 if (tty->ops->start)
1013 tty->ops->start(tty);
1017 void start_tty(struct tty_struct *tty)
1019 unsigned long flags;
1021 spin_lock_irqsave(&tty->flow_lock, flags);
1023 spin_unlock_irqrestore(&tty->flow_lock, flags);
1025 EXPORT_SYMBOL(start_tty);
1027 static void tty_update_time(struct timespec *time)
1029 unsigned long sec = get_seconds();
1032 * We only care if the two values differ in anything other than the
1033 * lower three bits (i.e every 8 seconds). If so, then we can update
1034 * the time of the tty device, otherwise it could be construded as a
1035 * security leak to let userspace know the exact timing of the tty.
1037 if ((sec ^ time->tv_sec) & ~7)
1042 * tty_read - read method for tty device files
1043 * @file: pointer to tty file
1045 * @count: size of user buffer
1048 * Perform the read system call function on this terminal device. Checks
1049 * for hung up devices before calling the line discipline method.
1052 * Locks the line discipline internally while needed. Multiple
1053 * read calls may be outstanding in parallel.
1056 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1060 struct inode *inode = file_inode(file);
1061 struct tty_struct *tty = file_tty(file);
1062 struct tty_ldisc *ld;
1064 if (tty_paranoia_check(tty, inode, "tty_read"))
1066 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1069 /* We want to wait for the line discipline to sort out in this
1071 ld = tty_ldisc_ref_wait(tty);
1073 i = ld->ops->read(tty, file, buf, count);
1076 tty_ldisc_deref(ld);
1079 tty_update_time(&inode->i_atime);
1084 static void tty_write_unlock(struct tty_struct *tty)
1086 mutex_unlock(&tty->atomic_write_lock);
1087 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1090 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1092 if (!mutex_trylock(&tty->atomic_write_lock)) {
1095 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1096 return -ERESTARTSYS;
1102 * Split writes up in sane blocksizes to avoid
1103 * denial-of-service type attacks
1105 static inline ssize_t do_tty_write(
1106 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1107 struct tty_struct *tty,
1109 const char __user *buf,
1112 ssize_t ret, written = 0;
1115 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1120 * We chunk up writes into a temporary buffer. This
1121 * simplifies low-level drivers immensely, since they
1122 * don't have locking issues and user mode accesses.
1124 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1127 * The default chunk-size is 2kB, because the NTTY
1128 * layer has problems with bigger chunks. It will
1129 * claim to be able to handle more characters than
1132 * FIXME: This can probably go away now except that 64K chunks
1133 * are too likely to fail unless switched to vmalloc...
1136 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1141 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1142 if (tty->write_cnt < chunk) {
1143 unsigned char *buf_chunk;
1148 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1153 kfree(tty->write_buf);
1154 tty->write_cnt = chunk;
1155 tty->write_buf = buf_chunk;
1158 /* Do the write .. */
1160 size_t size = count;
1164 if (copy_from_user(tty->write_buf, buf, size))
1166 ret = write(tty, file, tty->write_buf, size);
1175 if (signal_pending(current))
1180 tty_update_time(&file_inode(file)->i_mtime);
1184 tty_write_unlock(tty);
1189 * tty_write_message - write a message to a certain tty, not just the console.
1190 * @tty: the destination tty_struct
1191 * @msg: the message to write
1193 * This is used for messages that need to be redirected to a specific tty.
1194 * We don't put it into the syslog queue right now maybe in the future if
1197 * We must still hold the BTM and test the CLOSING flag for the moment.
1200 void tty_write_message(struct tty_struct *tty, char *msg)
1203 mutex_lock(&tty->atomic_write_lock);
1205 if (tty->ops->write && tty->count > 0)
1206 tty->ops->write(tty, msg, strlen(msg));
1208 tty_write_unlock(tty);
1215 * tty_write - write method for tty device file
1216 * @file: tty file pointer
1217 * @buf: user data to write
1218 * @count: bytes to write
1221 * Write data to a tty device via the line discipline.
1224 * Locks the line discipline as required
1225 * Writes to the tty driver are serialized by the atomic_write_lock
1226 * and are then processed in chunks to the device. The line discipline
1227 * write method will not be invoked in parallel for each device.
1230 static ssize_t tty_write(struct file *file, const char __user *buf,
1231 size_t count, loff_t *ppos)
1233 struct tty_struct *tty = file_tty(file);
1234 struct tty_ldisc *ld;
1237 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1239 if (!tty || !tty->ops->write ||
1240 (test_bit(TTY_IO_ERROR, &tty->flags)))
1242 /* Short term debug to catch buggy drivers */
1243 if (tty->ops->write_room == NULL)
1244 tty_err(tty, "missing write_room method\n");
1245 ld = tty_ldisc_ref_wait(tty);
1246 if (!ld->ops->write)
1249 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1250 tty_ldisc_deref(ld);
1254 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1255 size_t count, loff_t *ppos)
1257 struct file *p = NULL;
1259 spin_lock(&redirect_lock);
1261 p = get_file(redirect);
1262 spin_unlock(&redirect_lock);
1266 res = vfs_write(p, buf, count, &p->f_pos);
1270 return tty_write(file, buf, count, ppos);
1274 * tty_send_xchar - send priority character
1276 * Send a high priority character to the tty even if stopped
1278 * Locking: none for xchar method, write ordering for write method.
1281 int tty_send_xchar(struct tty_struct *tty, char ch)
1283 int was_stopped = tty->stopped;
1285 if (tty->ops->send_xchar) {
1286 down_read(&tty->termios_rwsem);
1287 tty->ops->send_xchar(tty, ch);
1288 up_read(&tty->termios_rwsem);
1292 if (tty_write_lock(tty, 0) < 0)
1293 return -ERESTARTSYS;
1295 down_read(&tty->termios_rwsem);
1298 tty->ops->write(tty, &ch, 1);
1301 up_read(&tty->termios_rwsem);
1302 tty_write_unlock(tty);
1306 static char ptychar[] = "pqrstuvwxyzabcde";
1309 * pty_line_name - generate name for a pty
1310 * @driver: the tty driver in use
1311 * @index: the minor number
1312 * @p: output buffer of at least 6 bytes
1314 * Generate a name from a driver reference and write it to the output
1319 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1321 int i = index + driver->name_base;
1322 /* ->name is initialized to "ttyp", but "tty" is expected */
1323 sprintf(p, "%s%c%x",
1324 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1325 ptychar[i >> 4 & 0xf], i & 0xf);
1329 * tty_line_name - generate name for a tty
1330 * @driver: the tty driver in use
1331 * @index: the minor number
1332 * @p: output buffer of at least 7 bytes
1334 * Generate a name from a driver reference and write it to the output
1339 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1341 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1342 return sprintf(p, "%s", driver->name);
1344 return sprintf(p, "%s%d", driver->name,
1345 index + driver->name_base);
1349 * tty_driver_lookup_tty() - find an existing tty, if any
1350 * @driver: the driver for the tty
1351 * @idx: the minor number
1353 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1354 * driver lookup() method returns an error.
1356 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1358 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1359 struct inode *inode, int idx)
1361 struct tty_struct *tty;
1363 if (driver->ops->lookup)
1364 tty = driver->ops->lookup(driver, inode, idx);
1366 tty = driver->ttys[idx];
1374 * tty_init_termios - helper for termios setup
1375 * @tty: the tty to set up
1377 * Initialise the termios structures for this tty. Thus runs under
1378 * the tty_mutex currently so we can be relaxed about ordering.
1381 int tty_init_termios(struct tty_struct *tty)
1383 struct ktermios *tp;
1384 int idx = tty->index;
1386 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1387 tty->termios = tty->driver->init_termios;
1389 /* Check for lazy saved data */
1390 tp = tty->driver->termios[idx];
1394 tty->termios = tty->driver->init_termios;
1396 /* Compatibility until drivers always set this */
1397 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1398 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1401 EXPORT_SYMBOL_GPL(tty_init_termios);
1403 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1405 int ret = tty_init_termios(tty);
1409 tty_driver_kref_get(driver);
1411 driver->ttys[tty->index] = tty;
1414 EXPORT_SYMBOL_GPL(tty_standard_install);
1417 * tty_driver_install_tty() - install a tty entry in the driver
1418 * @driver: the driver for the tty
1421 * Install a tty object into the driver tables. The tty->index field
1422 * will be set by the time this is called. This method is responsible
1423 * for ensuring any need additional structures are allocated and
1426 * Locking: tty_mutex for now
1428 static int tty_driver_install_tty(struct tty_driver *driver,
1429 struct tty_struct *tty)
1431 return driver->ops->install ? driver->ops->install(driver, tty) :
1432 tty_standard_install(driver, tty);
1436 * tty_driver_remove_tty() - remove a tty from the driver tables
1437 * @driver: the driver for the tty
1438 * @idx: the minor number
1440 * Remvoe a tty object from the driver tables. The tty->index field
1441 * will be set by the time this is called.
1443 * Locking: tty_mutex for now
1445 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1447 if (driver->ops->remove)
1448 driver->ops->remove(driver, tty);
1450 driver->ttys[tty->index] = NULL;
1454 * tty_reopen() - fast re-open of an open tty
1455 * @tty - the tty to open
1457 * Return 0 on success, -errno on error.
1458 * Re-opens on master ptys are not allowed and return -EIO.
1460 * Locking: Caller must hold tty_lock
1462 static int tty_reopen(struct tty_struct *tty)
1464 struct tty_driver *driver = tty->driver;
1469 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1470 driver->subtype == PTY_TYPE_MASTER)
1473 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1478 WARN_ON(!tty->ldisc);
1484 * tty_init_dev - initialise a tty device
1485 * @driver: tty driver we are opening a device on
1486 * @idx: device index
1487 * @ret_tty: returned tty structure
1489 * Prepare a tty device. This may not be a "new" clean device but
1490 * could also be an active device. The pty drivers require special
1491 * handling because of this.
1494 * The function is called under the tty_mutex, which
1495 * protects us from the tty struct or driver itself going away.
1497 * On exit the tty device has the line discipline attached and
1498 * a reference count of 1. If a pair was created for pty/tty use
1499 * and the other was a pty master then it too has a reference count of 1.
1501 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1502 * failed open. The new code protects the open with a mutex, so it's
1503 * really quite straightforward. The mutex locking can probably be
1504 * relaxed for the (most common) case of reopening a tty.
1507 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1509 struct tty_struct *tty;
1513 * First time open is complex, especially for PTY devices.
1514 * This code guarantees that either everything succeeds and the
1515 * TTY is ready for operation, or else the table slots are vacated
1516 * and the allocated memory released. (Except that the termios
1517 * and locked termios may be retained.)
1520 if (!try_module_get(driver->owner))
1521 return ERR_PTR(-ENODEV);
1523 tty = alloc_tty_struct(driver, idx);
1526 goto err_module_put;
1530 retval = tty_driver_install_tty(driver, tty);
1532 goto err_deinit_tty;
1535 tty->port = driver->ports[idx];
1537 WARN_RATELIMIT(!tty->port,
1538 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1539 __func__, tty->driver->name);
1541 tty->port->itty = tty;
1544 * Structures all installed ... call the ldisc open routines.
1545 * If we fail here just call release_tty to clean up. No need
1546 * to decrement the use counts, as release_tty doesn't care.
1548 retval = tty_ldisc_setup(tty, tty->link);
1550 goto err_release_tty;
1551 /* Return the tty locked so that it cannot vanish under the caller */
1556 deinitialize_tty_struct(tty);
1557 free_tty_struct(tty);
1559 module_put(driver->owner);
1560 return ERR_PTR(retval);
1562 /* call the tty release_tty routine to clean out this slot */
1565 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1567 release_tty(tty, idx);
1568 return ERR_PTR(retval);
1571 void tty_free_termios(struct tty_struct *tty)
1573 struct ktermios *tp;
1574 int idx = tty->index;
1576 /* If the port is going to reset then it has no termios to save */
1577 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1580 /* Stash the termios data */
1581 tp = tty->driver->termios[idx];
1583 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1586 tty->driver->termios[idx] = tp;
1590 EXPORT_SYMBOL(tty_free_termios);
1593 * tty_flush_works - flush all works of a tty/pty pair
1594 * @tty: tty device to flush works for (or either end of a pty pair)
1596 * Sync flush all works belonging to @tty (and the 'other' tty).
1598 static void tty_flush_works(struct tty_struct *tty)
1600 flush_work(&tty->SAK_work);
1601 flush_work(&tty->hangup_work);
1603 flush_work(&tty->link->SAK_work);
1604 flush_work(&tty->link->hangup_work);
1609 * release_one_tty - release tty structure memory
1610 * @kref: kref of tty we are obliterating
1612 * Releases memory associated with a tty structure, and clears out the
1613 * driver table slots. This function is called when a device is no longer
1614 * in use. It also gets called when setup of a device fails.
1617 * takes the file list lock internally when working on the list
1618 * of ttys that the driver keeps.
1620 * This method gets called from a work queue so that the driver private
1621 * cleanup ops can sleep (needed for USB at least)
1623 static void release_one_tty(struct work_struct *work)
1625 struct tty_struct *tty =
1626 container_of(work, struct tty_struct, hangup_work);
1627 struct tty_driver *driver = tty->driver;
1628 struct module *owner = driver->owner;
1630 if (tty->ops->cleanup)
1631 tty->ops->cleanup(tty);
1634 tty_driver_kref_put(driver);
1637 spin_lock(&tty_files_lock);
1638 list_del_init(&tty->tty_files);
1639 spin_unlock(&tty_files_lock);
1642 put_pid(tty->session);
1643 free_tty_struct(tty);
1646 static void queue_release_one_tty(struct kref *kref)
1648 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1650 /* The hangup queue is now free so we can reuse it rather than
1651 waste a chunk of memory for each port */
1652 INIT_WORK(&tty->hangup_work, release_one_tty);
1653 schedule_work(&tty->hangup_work);
1657 * tty_kref_put - release a tty kref
1660 * Release a reference to a tty device and if need be let the kref
1661 * layer destruct the object for us
1664 void tty_kref_put(struct tty_struct *tty)
1667 kref_put(&tty->kref, queue_release_one_tty);
1669 EXPORT_SYMBOL(tty_kref_put);
1672 * release_tty - release tty structure memory
1674 * Release both @tty and a possible linked partner (think pty pair),
1675 * and decrement the refcount of the backing module.
1679 * takes the file list lock internally when working on the list
1680 * of ttys that the driver keeps.
1683 static void release_tty(struct tty_struct *tty, int idx)
1685 /* This should always be true but check for the moment */
1686 WARN_ON(tty->index != idx);
1687 WARN_ON(!mutex_is_locked(&tty_mutex));
1688 if (tty->ops->shutdown)
1689 tty->ops->shutdown(tty);
1690 tty_free_termios(tty);
1691 tty_driver_remove_tty(tty->driver, tty);
1692 tty->port->itty = NULL;
1694 tty->link->port->itty = NULL;
1695 tty_buffer_cancel_work(tty->port);
1697 tty_kref_put(tty->link);
1702 * tty_release_checks - check a tty before real release
1703 * @tty: tty to check
1704 * @o_tty: link of @tty (if any)
1705 * @idx: index of the tty
1707 * Performs some paranoid checking before true release of the @tty.
1708 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1710 static int tty_release_checks(struct tty_struct *tty, int idx)
1712 #ifdef TTY_PARANOIA_CHECK
1713 if (idx < 0 || idx >= tty->driver->num) {
1714 tty_debug(tty, "bad idx %d\n", idx);
1718 /* not much to check for devpts */
1719 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1722 if (tty != tty->driver->ttys[idx]) {
1723 tty_debug(tty, "bad driver table[%d] = %p\n",
1724 idx, tty->driver->ttys[idx]);
1727 if (tty->driver->other) {
1728 struct tty_struct *o_tty = tty->link;
1730 if (o_tty != tty->driver->other->ttys[idx]) {
1731 tty_debug(tty, "bad other table[%d] = %p\n",
1732 idx, tty->driver->other->ttys[idx]);
1735 if (o_tty->link != tty) {
1736 tty_debug(tty, "bad link = %p\n", o_tty->link);
1745 * tty_release - vfs callback for close
1746 * @inode: inode of tty
1747 * @filp: file pointer for handle to tty
1749 * Called the last time each file handle is closed that references
1750 * this tty. There may however be several such references.
1753 * Takes bkl. See tty_release_dev
1755 * Even releasing the tty structures is a tricky business.. We have
1756 * to be very careful that the structures are all released at the
1757 * same time, as interrupts might otherwise get the wrong pointers.
1759 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1760 * lead to double frees or releasing memory still in use.
1763 int tty_release(struct inode *inode, struct file *filp)
1765 struct tty_struct *tty = file_tty(filp);
1766 struct tty_struct *o_tty = NULL;
1767 int do_sleep, final;
1772 if (tty_paranoia_check(tty, inode, __func__))
1776 check_tty_count(tty, __func__);
1778 __tty_fasync(-1, filp, 0);
1781 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1782 tty->driver->subtype == PTY_TYPE_MASTER)
1785 if (tty_release_checks(tty, idx)) {
1790 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1792 if (tty->ops->close)
1793 tty->ops->close(tty, filp);
1795 /* If tty is pty master, lock the slave pty (stable lock order) */
1796 tty_lock_slave(o_tty);
1799 * Sanity check: if tty->count is going to zero, there shouldn't be
1800 * any waiters on tty->read_wait or tty->write_wait. We test the
1801 * wait queues and kick everyone out _before_ actually starting to
1802 * close. This ensures that we won't block while releasing the tty
1805 * The test for the o_tty closing is necessary, since the master and
1806 * slave sides may close in any order. If the slave side closes out
1807 * first, its count will be one, since the master side holds an open.
1808 * Thus this test wouldn't be triggered at the time the slave closed,
1814 if (tty->count <= 1) {
1815 if (waitqueue_active(&tty->read_wait)) {
1816 wake_up_poll(&tty->read_wait, POLLIN);
1819 if (waitqueue_active(&tty->write_wait)) {
1820 wake_up_poll(&tty->write_wait, POLLOUT);
1824 if (o_tty && o_tty->count <= 1) {
1825 if (waitqueue_active(&o_tty->read_wait)) {
1826 wake_up_poll(&o_tty->read_wait, POLLIN);
1829 if (waitqueue_active(&o_tty->write_wait)) {
1830 wake_up_poll(&o_tty->write_wait, POLLOUT);
1839 tty_warn(tty, "read/write wait queue active!\n");
1841 schedule_timeout_killable(timeout);
1842 if (timeout < 120 * HZ)
1843 timeout = 2 * timeout + 1;
1845 timeout = MAX_SCHEDULE_TIMEOUT;
1849 if (--o_tty->count < 0) {
1850 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1854 if (--tty->count < 0) {
1855 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1860 * We've decremented tty->count, so we need to remove this file
1861 * descriptor off the tty->tty_files list; this serves two
1863 * - check_tty_count sees the correct number of file descriptors
1864 * associated with this tty.
1865 * - do_tty_hangup no longer sees this file descriptor as
1866 * something that needs to be handled for hangups.
1871 * Perform some housekeeping before deciding whether to return.
1873 * If _either_ side is closing, make sure there aren't any
1874 * processes that still think tty or o_tty is their controlling
1878 read_lock(&tasklist_lock);
1879 session_clear_tty(tty->session);
1881 session_clear_tty(o_tty->session);
1882 read_unlock(&tasklist_lock);
1885 /* check whether both sides are closing ... */
1886 final = !tty->count && !(o_tty && o_tty->count);
1888 tty_unlock_slave(o_tty);
1891 /* At this point, the tty->count == 0 should ensure a dead tty
1892 cannot be re-opened by a racing opener */
1897 tty_debug_hangup(tty, "final close\n");
1899 * Ask the line discipline code to release its structures
1901 tty_ldisc_release(tty);
1903 /* Wait for pending work before tty destruction commmences */
1904 tty_flush_works(tty);
1906 tty_debug_hangup(tty, "freeing structure\n");
1908 * The release_tty function takes care of the details of clearing
1909 * the slots and preserving the termios structure. The tty_unlock_pair
1910 * should be safe as we keep a kref while the tty is locked (so the
1911 * unlock never unlocks a freed tty).
1913 mutex_lock(&tty_mutex);
1914 release_tty(tty, idx);
1915 mutex_unlock(&tty_mutex);
1921 * tty_open_current_tty - get locked tty of current task
1922 * @device: device number
1923 * @filp: file pointer to tty
1924 * @return: locked tty of the current task iff @device is /dev/tty
1926 * Performs a re-open of the current task's controlling tty.
1928 * We cannot return driver and index like for the other nodes because
1929 * devpts will not work then. It expects inodes to be from devpts FS.
1931 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1933 struct tty_struct *tty;
1936 if (device != MKDEV(TTYAUX_MAJOR, 0))
1939 tty = get_current_tty();
1941 return ERR_PTR(-ENXIO);
1943 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1946 tty_kref_put(tty); /* safe to drop the kref now */
1948 retval = tty_reopen(tty);
1951 tty = ERR_PTR(retval);
1957 * tty_lookup_driver - lookup a tty driver for a given device file
1958 * @device: device number
1959 * @filp: file pointer to tty
1960 * @noctty: set if the device should not become a controlling tty
1961 * @index: index for the device in the @return driver
1962 * @return: driver for this inode (with increased refcount)
1964 * If @return is not erroneous, the caller is responsible to decrement the
1965 * refcount by tty_driver_kref_put.
1967 * Locking: tty_mutex protects get_tty_driver
1969 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1970 int *noctty, int *index)
1972 struct tty_driver *driver;
1976 case MKDEV(TTY_MAJOR, 0): {
1977 extern struct tty_driver *console_driver;
1978 driver = tty_driver_kref_get(console_driver);
1979 *index = fg_console;
1984 case MKDEV(TTYAUX_MAJOR, 1): {
1985 struct tty_driver *console_driver = console_device(index);
1986 if (console_driver) {
1987 driver = tty_driver_kref_get(console_driver);
1989 /* Don't let /dev/console block */
1990 filp->f_flags |= O_NONBLOCK;
1995 return ERR_PTR(-ENODEV);
1998 driver = get_tty_driver(device, index);
2000 return ERR_PTR(-ENODEV);
2007 * tty_open - open a tty device
2008 * @inode: inode of device file
2009 * @filp: file pointer to tty
2011 * tty_open and tty_release keep up the tty count that contains the
2012 * number of opens done on a tty. We cannot use the inode-count, as
2013 * different inodes might point to the same tty.
2015 * Open-counting is needed for pty masters, as well as for keeping
2016 * track of serial lines: DTR is dropped when the last close happens.
2017 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2019 * The termios state of a pty is reset on first open so that
2020 * settings don't persist across reuse.
2022 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2023 * tty->count should protect the rest.
2024 * ->siglock protects ->signal/->sighand
2026 * Note: the tty_unlock/lock cases without a ref are only safe due to
2030 static int tty_open(struct inode *inode, struct file *filp)
2032 struct tty_struct *tty;
2034 struct tty_driver *driver = NULL;
2036 dev_t device = inode->i_rdev;
2037 unsigned saved_flags = filp->f_flags;
2039 nonseekable_open(inode, filp);
2042 retval = tty_alloc_file(filp);
2046 noctty = filp->f_flags & O_NOCTTY;
2050 tty = tty_open_current_tty(device, filp);
2052 mutex_lock(&tty_mutex);
2053 driver = tty_lookup_driver(device, filp, &noctty, &index);
2054 if (IS_ERR(driver)) {
2055 retval = PTR_ERR(driver);
2059 /* check whether we're reopening an existing tty */
2060 tty = tty_driver_lookup_tty(driver, inode, index);
2062 retval = PTR_ERR(tty);
2067 mutex_unlock(&tty_mutex);
2069 /* safe to drop the kref from tty_driver_lookup_tty() */
2071 retval = tty_reopen(tty);
2074 tty = ERR_PTR(retval);
2076 } else { /* Returns with the tty_lock held for now */
2077 tty = tty_init_dev(driver, index);
2078 mutex_unlock(&tty_mutex);
2081 tty_driver_kref_put(driver);
2085 retval = PTR_ERR(tty);
2089 tty_add_file(tty, filp);
2091 check_tty_count(tty, __func__);
2092 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2093 tty->driver->subtype == PTY_TYPE_MASTER)
2096 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2099 retval = tty->ops->open(tty, filp);
2102 filp->f_flags = saved_flags;
2105 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2107 tty_unlock(tty); /* need to call tty_release without BTM */
2108 tty_release(inode, filp);
2109 if (retval != -ERESTARTSYS)
2112 if (signal_pending(current))
2117 * Need to reset f_op in case a hangup happened.
2119 if (tty_hung_up_p(filp))
2120 filp->f_op = &tty_fops;
2123 clear_bit(TTY_HUPPED, &tty->flags);
2126 read_lock(&tasklist_lock);
2127 spin_lock_irq(¤t->sighand->siglock);
2129 current->signal->leader &&
2130 !current->signal->tty &&
2131 tty->session == NULL) {
2133 * Don't let a process that only has write access to the tty
2134 * obtain the privileges associated with having a tty as
2135 * controlling terminal (being able to reopen it with full
2136 * access through /dev/tty, being able to perform pushback).
2137 * Many distributions set the group of all ttys to "tty" and
2138 * grant write-only access to all terminals for setgid tty
2139 * binaries, which should not imply full privileges on all ttys.
2141 * This could theoretically break old code that performs open()
2142 * on a write-only file descriptor. In that case, it might be
2143 * necessary to also permit this if
2144 * inode_permission(inode, MAY_READ) == 0.
2146 if (filp->f_mode & FMODE_READ)
2147 __proc_set_tty(tty);
2149 spin_unlock_irq(¤t->sighand->siglock);
2150 read_unlock(&tasklist_lock);
2154 mutex_unlock(&tty_mutex);
2155 /* after locks to avoid deadlock */
2156 if (!IS_ERR_OR_NULL(driver))
2157 tty_driver_kref_put(driver);
2159 tty_free_file(filp);
2166 * tty_poll - check tty status
2167 * @filp: file being polled
2168 * @wait: poll wait structures to update
2170 * Call the line discipline polling method to obtain the poll
2171 * status of the device.
2173 * Locking: locks called line discipline but ldisc poll method
2174 * may be re-entered freely by other callers.
2177 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2179 struct tty_struct *tty = file_tty(filp);
2180 struct tty_ldisc *ld;
2183 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2186 ld = tty_ldisc_ref_wait(tty);
2188 ret = ld->ops->poll(tty, filp, wait);
2189 tty_ldisc_deref(ld);
2193 static int __tty_fasync(int fd, struct file *filp, int on)
2195 struct tty_struct *tty = file_tty(filp);
2196 struct tty_ldisc *ldisc;
2197 unsigned long flags;
2200 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2203 retval = fasync_helper(fd, filp, on, &tty->fasync);
2207 ldisc = tty_ldisc_ref(tty);
2209 if (ldisc->ops->fasync)
2210 ldisc->ops->fasync(tty, on);
2211 tty_ldisc_deref(ldisc);
2218 spin_lock_irqsave(&tty->ctrl_lock, flags);
2221 type = PIDTYPE_PGID;
2223 pid = task_pid(current);
2227 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2228 __f_setown(filp, pid, type, 0);
2236 static int tty_fasync(int fd, struct file *filp, int on)
2238 struct tty_struct *tty = file_tty(filp);
2242 retval = __tty_fasync(fd, filp, on);
2249 * tiocsti - fake input character
2250 * @tty: tty to fake input into
2251 * @p: pointer to character
2253 * Fake input to a tty device. Does the necessary locking and
2256 * FIXME: does not honour flow control ??
2259 * Called functions take tty_ldiscs_lock
2260 * current->signal->tty check is safe without locks
2262 * FIXME: may race normal receive processing
2265 static int tiocsti(struct tty_struct *tty, char __user *p)
2268 struct tty_ldisc *ld;
2270 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2272 if (get_user(ch, p))
2274 tty_audit_tiocsti(tty, ch);
2275 ld = tty_ldisc_ref_wait(tty);
2276 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2277 tty_ldisc_deref(ld);
2282 * tiocgwinsz - implement window query ioctl
2284 * @arg: user buffer for result
2286 * Copies the kernel idea of the window size into the user buffer.
2288 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2292 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2296 mutex_lock(&tty->winsize_mutex);
2297 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2298 mutex_unlock(&tty->winsize_mutex);
2300 return err ? -EFAULT: 0;
2304 * tty_do_resize - resize event
2305 * @tty: tty being resized
2306 * @rows: rows (character)
2307 * @cols: cols (character)
2309 * Update the termios variables and send the necessary signals to
2310 * peform a terminal resize correctly
2313 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2318 mutex_lock(&tty->winsize_mutex);
2319 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2322 /* Signal the foreground process group */
2323 pgrp = tty_get_pgrp(tty);
2325 kill_pgrp(pgrp, SIGWINCH, 1);
2330 mutex_unlock(&tty->winsize_mutex);
2333 EXPORT_SYMBOL(tty_do_resize);
2336 * tiocswinsz - implement window size set ioctl
2337 * @tty; tty side of tty
2338 * @arg: user buffer for result
2340 * Copies the user idea of the window size to the kernel. Traditionally
2341 * this is just advisory information but for the Linux console it
2342 * actually has driver level meaning and triggers a VC resize.
2345 * Driver dependent. The default do_resize method takes the
2346 * tty termios mutex and ctrl_lock. The console takes its own lock
2347 * then calls into the default method.
2350 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2352 struct winsize tmp_ws;
2353 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2356 if (tty->ops->resize)
2357 return tty->ops->resize(tty, &tmp_ws);
2359 return tty_do_resize(tty, &tmp_ws);
2363 * tioccons - allow admin to move logical console
2364 * @file: the file to become console
2366 * Allow the administrator to move the redirected console device
2368 * Locking: uses redirect_lock to guard the redirect information
2371 static int tioccons(struct file *file)
2373 if (!capable(CAP_SYS_ADMIN))
2375 if (file->f_op->write == redirected_tty_write) {
2377 spin_lock(&redirect_lock);
2380 spin_unlock(&redirect_lock);
2385 spin_lock(&redirect_lock);
2387 spin_unlock(&redirect_lock);
2390 redirect = get_file(file);
2391 spin_unlock(&redirect_lock);
2396 * fionbio - non blocking ioctl
2397 * @file: file to set blocking value
2398 * @p: user parameter
2400 * Historical tty interfaces had a blocking control ioctl before
2401 * the generic functionality existed. This piece of history is preserved
2402 * in the expected tty API of posix OS's.
2404 * Locking: none, the open file handle ensures it won't go away.
2407 static int fionbio(struct file *file, int __user *p)
2411 if (get_user(nonblock, p))
2414 spin_lock(&file->f_lock);
2416 file->f_flags |= O_NONBLOCK;
2418 file->f_flags &= ~O_NONBLOCK;
2419 spin_unlock(&file->f_lock);
2424 * tiocsctty - set controlling tty
2425 * @tty: tty structure
2426 * @arg: user argument
2428 * This ioctl is used to manage job control. It permits a session
2429 * leader to set this tty as the controlling tty for the session.
2432 * Takes tty_lock() to serialize proc_set_tty() for this tty
2433 * Takes tasklist_lock internally to walk sessions
2434 * Takes ->siglock() when updating signal->tty
2437 static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2442 read_lock(&tasklist_lock);
2444 if (current->signal->leader && (task_session(current) == tty->session))
2448 * The process must be a session leader and
2449 * not have a controlling tty already.
2451 if (!current->signal->leader || current->signal->tty) {
2458 * This tty is already the controlling
2459 * tty for another session group!
2461 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2465 session_clear_tty(tty->session);
2472 /* See the comment in tty_open(). */
2473 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2480 read_unlock(&tasklist_lock);
2486 * tty_get_pgrp - return a ref counted pgrp pid
2489 * Returns a refcounted instance of the pid struct for the process
2490 * group controlling the tty.
2493 struct pid *tty_get_pgrp(struct tty_struct *tty)
2495 unsigned long flags;
2498 spin_lock_irqsave(&tty->ctrl_lock, flags);
2499 pgrp = get_pid(tty->pgrp);
2500 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2504 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2507 * This checks not only the pgrp, but falls back on the pid if no
2508 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2511 * The caller must hold rcu lock or the tasklist lock.
2513 static struct pid *session_of_pgrp(struct pid *pgrp)
2515 struct task_struct *p;
2516 struct pid *sid = NULL;
2518 p = pid_task(pgrp, PIDTYPE_PGID);
2520 p = pid_task(pgrp, PIDTYPE_PID);
2522 sid = task_session(p);
2528 * tiocgpgrp - get process group
2529 * @tty: tty passed by user
2530 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2533 * Obtain the process group of the tty. If there is no process group
2536 * Locking: none. Reference to current->signal->tty is safe.
2539 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2544 * (tty == real_tty) is a cheap way of
2545 * testing if the tty is NOT a master pty.
2547 if (tty == real_tty && current->signal->tty != real_tty)
2549 pid = tty_get_pgrp(real_tty);
2550 ret = put_user(pid_vnr(pid), p);
2556 * tiocspgrp - attempt to set process group
2557 * @tty: tty passed by user
2558 * @real_tty: tty side device matching tty passed by user
2561 * Set the process group of the tty to the session passed. Only
2562 * permitted where the tty session is our session.
2564 * Locking: RCU, ctrl lock
2567 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2571 int retval = tty_check_change(real_tty);
2577 if (!current->signal->tty ||
2578 (current->signal->tty != real_tty) ||
2579 (real_tty->session != task_session(current)))
2581 if (get_user(pgrp_nr, p))
2586 pgrp = find_vpid(pgrp_nr);
2591 if (session_of_pgrp(pgrp) != task_session(current))
2594 spin_lock_irq(&tty->ctrl_lock);
2595 put_pid(real_tty->pgrp);
2596 real_tty->pgrp = get_pid(pgrp);
2597 spin_unlock_irq(&tty->ctrl_lock);
2604 * tiocgsid - get session id
2605 * @tty: tty passed by user
2606 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2607 * @p: pointer to returned session id
2609 * Obtain the session id of the tty. If there is no session
2612 * Locking: none. Reference to current->signal->tty is safe.
2615 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2618 * (tty == real_tty) is a cheap way of
2619 * testing if the tty is NOT a master pty.
2621 if (tty == real_tty && current->signal->tty != real_tty)
2623 if (!real_tty->session)
2625 return put_user(pid_vnr(real_tty->session), p);
2629 * tiocsetd - set line discipline
2631 * @p: pointer to user data
2633 * Set the line discipline according to user request.
2635 * Locking: see tty_set_ldisc, this function is just a helper
2638 static int tiocsetd(struct tty_struct *tty, int __user *p)
2643 if (get_user(ldisc, p))
2646 ret = tty_set_ldisc(tty, ldisc);
2652 * send_break - performed time break
2653 * @tty: device to break on
2654 * @duration: timeout in mS
2656 * Perform a timed break on hardware that lacks its own driver level
2657 * timed break functionality.
2660 * atomic_write_lock serializes
2664 static int send_break(struct tty_struct *tty, unsigned int duration)
2668 if (tty->ops->break_ctl == NULL)
2671 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2672 retval = tty->ops->break_ctl(tty, duration);
2674 /* Do the work ourselves */
2675 if (tty_write_lock(tty, 0) < 0)
2677 retval = tty->ops->break_ctl(tty, -1);
2680 if (!signal_pending(current))
2681 msleep_interruptible(duration);
2682 retval = tty->ops->break_ctl(tty, 0);
2684 tty_write_unlock(tty);
2685 if (signal_pending(current))
2692 * tty_tiocmget - get modem status
2694 * @file: user file pointer
2695 * @p: pointer to result
2697 * Obtain the modem status bits from the tty driver if the feature
2698 * is supported. Return -EINVAL if it is not available.
2700 * Locking: none (up to the driver)
2703 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2705 int retval = -EINVAL;
2707 if (tty->ops->tiocmget) {
2708 retval = tty->ops->tiocmget(tty);
2711 retval = put_user(retval, p);
2717 * tty_tiocmset - set modem status
2719 * @cmd: command - clear bits, set bits or set all
2720 * @p: pointer to desired bits
2722 * Set the modem status bits from the tty driver if the feature
2723 * is supported. Return -EINVAL if it is not available.
2725 * Locking: none (up to the driver)
2728 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2732 unsigned int set, clear, val;
2734 if (tty->ops->tiocmset == NULL)
2737 retval = get_user(val, p);
2753 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2754 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2755 return tty->ops->tiocmset(tty, set, clear);
2758 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2760 int retval = -EINVAL;
2761 struct serial_icounter_struct icount;
2762 memset(&icount, 0, sizeof(icount));
2763 if (tty->ops->get_icount)
2764 retval = tty->ops->get_icount(tty, &icount);
2767 if (copy_to_user(arg, &icount, sizeof(icount)))
2772 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2774 static DEFINE_RATELIMIT_STATE(depr_flags,
2775 DEFAULT_RATELIMIT_INTERVAL,
2776 DEFAULT_RATELIMIT_BURST);
2777 char comm[TASK_COMM_LEN];
2780 if (get_user(flags, &ss->flags))
2783 flags &= ASYNC_DEPRECATED;
2785 if (flags && __ratelimit(&depr_flags))
2786 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2787 __func__, get_task_comm(comm, current), flags);
2791 * if pty, return the slave side (real_tty)
2792 * otherwise, return self
2794 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2796 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2797 tty->driver->subtype == PTY_TYPE_MASTER)
2803 * Split this up, as gcc can choke on it otherwise..
2805 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2807 struct tty_struct *tty = file_tty(file);
2808 struct tty_struct *real_tty;
2809 void __user *p = (void __user *)arg;
2811 struct tty_ldisc *ld;
2813 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2816 real_tty = tty_pair_get_tty(tty);
2819 * Factor out some common prep work
2827 retval = tty_check_change(tty);
2830 if (cmd != TIOCCBRK) {
2831 tty_wait_until_sent(tty, 0);
2832 if (signal_pending(current))
2843 return tiocsti(tty, p);
2845 return tiocgwinsz(real_tty, p);
2847 return tiocswinsz(real_tty, p);
2849 return real_tty != tty ? -EINVAL : tioccons(file);
2851 return fionbio(file, p);
2853 set_bit(TTY_EXCLUSIVE, &tty->flags);
2856 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2860 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2861 return put_user(excl, (int __user *)p);
2864 if (current->signal->tty != tty)
2869 return tiocsctty(real_tty, file, arg);
2871 return tiocgpgrp(tty, real_tty, p);
2873 return tiocspgrp(tty, real_tty, p);
2875 return tiocgsid(tty, real_tty, p);
2877 return put_user(tty->ldisc->ops->num, (int __user *)p);
2879 return tiocsetd(tty, p);
2881 if (!capable(CAP_SYS_ADMIN))
2887 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2888 return put_user(ret, (unsigned int __user *)p);
2893 case TIOCSBRK: /* Turn break on, unconditionally */
2894 if (tty->ops->break_ctl)
2895 return tty->ops->break_ctl(tty, -1);
2897 case TIOCCBRK: /* Turn break off, unconditionally */
2898 if (tty->ops->break_ctl)
2899 return tty->ops->break_ctl(tty, 0);
2901 case TCSBRK: /* SVID version: non-zero arg --> no break */
2902 /* non-zero arg means wait for all output data
2903 * to be sent (performed above) but don't send break.
2904 * This is used by the tcdrain() termios function.
2907 return send_break(tty, 250);
2909 case TCSBRKP: /* support for POSIX tcsendbreak() */
2910 return send_break(tty, arg ? arg*100 : 250);
2913 return tty_tiocmget(tty, p);
2917 return tty_tiocmset(tty, cmd, p);
2919 retval = tty_tiocgicount(tty, p);
2920 /* For the moment allow fall through to the old method */
2921 if (retval != -EINVAL)
2928 /* flush tty buffer and allow ldisc to process ioctl */
2929 tty_buffer_flush(tty, NULL);
2934 tty_warn_deprecated_flags(p);
2937 if (tty->ops->ioctl) {
2938 retval = tty->ops->ioctl(tty, cmd, arg);
2939 if (retval != -ENOIOCTLCMD)
2942 ld = tty_ldisc_ref_wait(tty);
2944 if (ld->ops->ioctl) {
2945 retval = ld->ops->ioctl(tty, file, cmd, arg);
2946 if (retval == -ENOIOCTLCMD)
2949 tty_ldisc_deref(ld);
2953 #ifdef CONFIG_COMPAT
2954 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2957 struct tty_struct *tty = file_tty(file);
2958 struct tty_ldisc *ld;
2959 int retval = -ENOIOCTLCMD;
2961 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2964 if (tty->ops->compat_ioctl) {
2965 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2966 if (retval != -ENOIOCTLCMD)
2970 ld = tty_ldisc_ref_wait(tty);
2971 if (ld->ops->compat_ioctl)
2972 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2974 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2975 tty_ldisc_deref(ld);
2981 static int this_tty(const void *t, struct file *file, unsigned fd)
2983 if (likely(file->f_op->read != tty_read))
2985 return file_tty(file) != t ? 0 : fd + 1;
2989 * This implements the "Secure Attention Key" --- the idea is to
2990 * prevent trojan horses by killing all processes associated with this
2991 * tty when the user hits the "Secure Attention Key". Required for
2992 * super-paranoid applications --- see the Orange Book for more details.
2994 * This code could be nicer; ideally it should send a HUP, wait a few
2995 * seconds, then send a INT, and then a KILL signal. But you then
2996 * have to coordinate with the init process, since all processes associated
2997 * with the current tty must be dead before the new getty is allowed
3000 * Now, if it would be correct ;-/ The current code has a nasty hole -
3001 * it doesn't catch files in flight. We may send the descriptor to ourselves
3002 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3004 * Nasty bug: do_SAK is being called in interrupt context. This can
3005 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3007 void __do_SAK(struct tty_struct *tty)
3012 struct task_struct *g, *p;
3013 struct pid *session;
3018 session = tty->session;
3020 tty_ldisc_flush(tty);
3022 tty_driver_flush_buffer(tty);
3024 read_lock(&tasklist_lock);
3025 /* Kill the entire session */
3026 do_each_pid_task(session, PIDTYPE_SID, p) {
3027 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3028 task_pid_nr(p), p->comm);
3029 send_sig(SIGKILL, p, 1);
3030 } while_each_pid_task(session, PIDTYPE_SID, p);
3032 /* Now kill any processes that happen to have the tty open */
3033 do_each_thread(g, p) {
3034 if (p->signal->tty == tty) {
3035 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3036 task_pid_nr(p), p->comm);
3037 send_sig(SIGKILL, p, 1);
3041 i = iterate_fd(p->files, 0, this_tty, tty);
3043 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3044 task_pid_nr(p), p->comm, i - 1);
3045 force_sig(SIGKILL, p);
3048 } while_each_thread(g, p);
3049 read_unlock(&tasklist_lock);
3053 static void do_SAK_work(struct work_struct *work)
3055 struct tty_struct *tty =
3056 container_of(work, struct tty_struct, SAK_work);
3061 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3062 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3063 * the values which we write to it will be identical to the values which it
3064 * already has. --akpm
3066 void do_SAK(struct tty_struct *tty)
3070 schedule_work(&tty->SAK_work);
3073 EXPORT_SYMBOL(do_SAK);
3075 static int dev_match_devt(struct device *dev, const void *data)
3077 const dev_t *devt = data;
3078 return dev->devt == *devt;
3081 /* Must put_device() after it's unused! */
3082 static struct device *tty_get_device(struct tty_struct *tty)
3084 dev_t devt = tty_devnum(tty);
3085 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3092 * This subroutine allocates and initializes a tty structure.
3094 * Locking: none - tty in question is not exposed at this point
3097 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3099 struct tty_struct *tty;
3101 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3105 kref_init(&tty->kref);
3106 tty->magic = TTY_MAGIC;
3107 tty_ldisc_init(tty);
3108 tty->session = NULL;
3110 mutex_init(&tty->legacy_mutex);
3111 mutex_init(&tty->throttle_mutex);
3112 init_rwsem(&tty->termios_rwsem);
3113 mutex_init(&tty->winsize_mutex);
3114 init_ldsem(&tty->ldisc_sem);
3115 init_waitqueue_head(&tty->write_wait);
3116 init_waitqueue_head(&tty->read_wait);
3117 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3118 mutex_init(&tty->atomic_write_lock);
3119 spin_lock_init(&tty->ctrl_lock);
3120 spin_lock_init(&tty->flow_lock);
3121 INIT_LIST_HEAD(&tty->tty_files);
3122 INIT_WORK(&tty->SAK_work, do_SAK_work);
3124 tty->driver = driver;
3125 tty->ops = driver->ops;
3127 tty_line_name(driver, idx, tty->name);
3128 tty->dev = tty_get_device(tty);
3134 * deinitialize_tty_struct
3135 * @tty: tty to deinitialize
3137 * This subroutine deinitializes a tty structure that has been newly
3138 * allocated but tty_release cannot be called on that yet.
3140 * Locking: none - tty in question must not be exposed at this point
3142 void deinitialize_tty_struct(struct tty_struct *tty)
3144 tty_ldisc_deinit(tty);
3148 * tty_put_char - write one character to a tty
3152 * Write one byte to the tty using the provided put_char method
3153 * if present. Returns the number of characters successfully output.
3155 * Note: the specific put_char operation in the driver layer may go
3156 * away soon. Don't call it directly, use this method
3159 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3161 if (tty->ops->put_char)
3162 return tty->ops->put_char(tty, ch);
3163 return tty->ops->write(tty, &ch, 1);
3165 EXPORT_SYMBOL_GPL(tty_put_char);
3167 struct class *tty_class;
3169 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3170 unsigned int index, unsigned int count)
3174 /* init here, since reused cdevs cause crashes */
3175 driver->cdevs[index] = cdev_alloc();
3176 if (!driver->cdevs[index])
3178 driver->cdevs[index]->ops = &tty_fops;
3179 driver->cdevs[index]->owner = driver->owner;
3180 err = cdev_add(driver->cdevs[index], dev, count);
3182 kobject_put(&driver->cdevs[index]->kobj);
3187 * tty_register_device - register a tty device
3188 * @driver: the tty driver that describes the tty device
3189 * @index: the index in the tty driver for this tty device
3190 * @device: a struct device that is associated with this tty device.
3191 * This field is optional, if there is no known struct device
3192 * for this tty device it can be set to NULL safely.
3194 * Returns a pointer to the struct device for this tty device
3195 * (or ERR_PTR(-EFOO) on error).
3197 * This call is required to be made to register an individual tty device
3198 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3199 * that bit is not set, this function should not be called by a tty
3205 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3206 struct device *device)
3208 return tty_register_device_attr(driver, index, device, NULL, NULL);
3210 EXPORT_SYMBOL(tty_register_device);
3212 static void tty_device_create_release(struct device *dev)
3214 dev_dbg(dev, "releasing...\n");
3219 * tty_register_device_attr - register a tty device
3220 * @driver: the tty driver that describes the tty device
3221 * @index: the index in the tty driver for this tty device
3222 * @device: a struct device that is associated with this tty device.
3223 * This field is optional, if there is no known struct device
3224 * for this tty device it can be set to NULL safely.
3225 * @drvdata: Driver data to be set to device.
3226 * @attr_grp: Attribute group to be set on device.
3228 * Returns a pointer to the struct device for this tty device
3229 * (or ERR_PTR(-EFOO) on error).
3231 * This call is required to be made to register an individual tty device
3232 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3233 * that bit is not set, this function should not be called by a tty
3238 struct device *tty_register_device_attr(struct tty_driver *driver,
3239 unsigned index, struct device *device,
3241 const struct attribute_group **attr_grp)
3244 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3245 struct device *dev = NULL;
3246 int retval = -ENODEV;
3249 if (index >= driver->num) {
3250 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3251 driver->name, index);
3252 return ERR_PTR(-EINVAL);
3255 if (driver->type == TTY_DRIVER_TYPE_PTY)
3256 pty_line_name(driver, index, name);
3258 tty_line_name(driver, index, name);
3260 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3261 retval = tty_cdev_add(driver, devt, index, 1);
3267 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3274 dev->class = tty_class;
3275 dev->parent = device;
3276 dev->release = tty_device_create_release;
3277 dev_set_name(dev, "%s", name);
3278 dev->groups = attr_grp;
3279 dev_set_drvdata(dev, drvdata);
3281 retval = device_register(dev);
3290 cdev_del(driver->cdevs[index]);
3291 driver->cdevs[index] = NULL;
3293 return ERR_PTR(retval);
3295 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3298 * tty_unregister_device - unregister 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
3302 * If a tty device is registered with a call to tty_register_device() then
3303 * this function must be called when the tty device is gone.
3308 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3310 device_destroy(tty_class,
3311 MKDEV(driver->major, driver->minor_start) + index);
3312 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3313 cdev_del(driver->cdevs[index]);
3314 driver->cdevs[index] = NULL;
3317 EXPORT_SYMBOL(tty_unregister_device);
3320 * __tty_alloc_driver -- allocate tty driver
3321 * @lines: count of lines this driver can handle at most
3322 * @owner: module which is repsonsible for this driver
3323 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3325 * This should not be called directly, some of the provided macros should be
3326 * used instead. Use IS_ERR and friends on @retval.
3328 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3329 unsigned long flags)
3331 struct tty_driver *driver;
3332 unsigned int cdevs = 1;
3335 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3336 return ERR_PTR(-EINVAL);
3338 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3340 return ERR_PTR(-ENOMEM);
3342 kref_init(&driver->kref);
3343 driver->magic = TTY_DRIVER_MAGIC;
3344 driver->num = lines;
3345 driver->owner = owner;
3346 driver->flags = flags;
3348 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3349 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3351 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3353 if (!driver->ttys || !driver->termios) {
3359 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3360 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3362 if (!driver->ports) {
3369 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3370 if (!driver->cdevs) {
3377 kfree(driver->ports);
3378 kfree(driver->ttys);
3379 kfree(driver->termios);
3380 kfree(driver->cdevs);
3382 return ERR_PTR(err);
3384 EXPORT_SYMBOL(__tty_alloc_driver);
3386 static void destruct_tty_driver(struct kref *kref)
3388 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3390 struct ktermios *tp;
3392 if (driver->flags & TTY_DRIVER_INSTALLED) {
3394 * Free the termios and termios_locked structures because
3395 * we don't want to get memory leaks when modular tty
3396 * drivers are removed from the kernel.
3398 for (i = 0; i < driver->num; i++) {
3399 tp = driver->termios[i];
3401 driver->termios[i] = NULL;
3404 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3405 tty_unregister_device(driver, i);
3407 proc_tty_unregister_driver(driver);
3408 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3409 cdev_del(driver->cdevs[0]);
3411 kfree(driver->cdevs);
3412 kfree(driver->ports);
3413 kfree(driver->termios);
3414 kfree(driver->ttys);
3418 void tty_driver_kref_put(struct tty_driver *driver)
3420 kref_put(&driver->kref, destruct_tty_driver);
3422 EXPORT_SYMBOL(tty_driver_kref_put);
3424 void tty_set_operations(struct tty_driver *driver,
3425 const struct tty_operations *op)
3429 EXPORT_SYMBOL(tty_set_operations);
3431 void put_tty_driver(struct tty_driver *d)
3433 tty_driver_kref_put(d);
3435 EXPORT_SYMBOL(put_tty_driver);
3438 * Called by a tty driver to register itself.
3440 int tty_register_driver(struct tty_driver *driver)
3447 if (!driver->major) {
3448 error = alloc_chrdev_region(&dev, driver->minor_start,
3449 driver->num, driver->name);
3451 driver->major = MAJOR(dev);
3452 driver->minor_start = MINOR(dev);
3455 dev = MKDEV(driver->major, driver->minor_start);
3456 error = register_chrdev_region(dev, driver->num, driver->name);
3461 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3462 error = tty_cdev_add(driver, dev, 0, driver->num);
3464 goto err_unreg_char;
3467 mutex_lock(&tty_mutex);
3468 list_add(&driver->tty_drivers, &tty_drivers);
3469 mutex_unlock(&tty_mutex);
3471 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3472 for (i = 0; i < driver->num; i++) {
3473 d = tty_register_device(driver, i, NULL);
3476 goto err_unreg_devs;
3480 proc_tty_register_driver(driver);
3481 driver->flags |= TTY_DRIVER_INSTALLED;
3485 for (i--; i >= 0; i--)
3486 tty_unregister_device(driver, i);
3488 mutex_lock(&tty_mutex);
3489 list_del(&driver->tty_drivers);
3490 mutex_unlock(&tty_mutex);
3493 unregister_chrdev_region(dev, driver->num);
3497 EXPORT_SYMBOL(tty_register_driver);
3500 * Called by a tty driver to unregister itself.
3502 int tty_unregister_driver(struct tty_driver *driver)
3506 if (driver->refcount)
3509 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3511 mutex_lock(&tty_mutex);
3512 list_del(&driver->tty_drivers);
3513 mutex_unlock(&tty_mutex);
3517 EXPORT_SYMBOL(tty_unregister_driver);
3519 dev_t tty_devnum(struct tty_struct *tty)
3521 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3523 EXPORT_SYMBOL(tty_devnum);
3525 void tty_default_fops(struct file_operations *fops)
3531 * Initialize the console device. This is called *early*, so
3532 * we can't necessarily depend on lots of kernel help here.
3533 * Just do some early initializations, and do the complex setup
3536 void __init console_init(void)
3540 /* Setup the default TTY line discipline. */
3544 * set up the console device so that later boot sequences can
3545 * inform about problems etc..
3547 call = __con_initcall_start;
3548 while (call < __con_initcall_end) {
3554 static char *tty_devnode(struct device *dev, umode_t *mode)
3558 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3559 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3564 static int __init tty_class_init(void)
3566 tty_class = class_create(THIS_MODULE, "tty");
3567 if (IS_ERR(tty_class))
3568 return PTR_ERR(tty_class);
3569 tty_class->devnode = tty_devnode;
3573 postcore_initcall(tty_class_init);
3575 /* 3/2004 jmc: why do these devices exist? */
3576 static struct cdev tty_cdev, console_cdev;
3578 static ssize_t show_cons_active(struct device *dev,
3579 struct device_attribute *attr, char *buf)
3581 struct console *cs[16];
3587 for_each_console(c) {
3592 if ((c->flags & CON_ENABLED) == 0)
3595 if (i >= ARRAY_SIZE(cs))
3599 int index = cs[i]->index;
3600 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3602 /* don't resolve tty0 as some programs depend on it */
3603 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3604 count += tty_line_name(drv, index, buf + count);
3606 count += sprintf(buf + count, "%s%d",
3607 cs[i]->name, cs[i]->index);
3609 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3615 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3617 static struct attribute *cons_dev_attrs[] = {
3618 &dev_attr_active.attr,
3622 ATTRIBUTE_GROUPS(cons_dev);
3624 static struct device *consdev;
3626 void console_sysfs_notify(void)
3629 sysfs_notify(&consdev->kobj, NULL, "active");
3633 * Ok, now we can initialize the rest of the tty devices and can count
3634 * on memory allocations, interrupts etc..
3636 int __init tty_init(void)
3638 cdev_init(&tty_cdev, &tty_fops);
3639 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3640 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3641 panic("Couldn't register /dev/tty driver\n");
3642 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3644 cdev_init(&console_cdev, &console_fops);
3645 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3646 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3647 panic("Couldn't register /dev/console driver\n");
3648 consdev = device_create_with_groups(tty_class, NULL,
3649 MKDEV(TTYAUX_MAJOR, 1), NULL,
3650 cons_dev_groups, "console");
3651 if (IS_ERR(consdev))
3655 vty_init(&console_fops);