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 (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);
517 * proc_set_tty - set the controlling terminal
519 * Only callable by the session leader and only if it does not already have
520 * a controlling terminal.
522 * Caller must hold: tty_lock()
523 * a readlock on tasklist_lock
526 static void __proc_set_tty(struct tty_struct *tty)
530 spin_lock_irqsave(&tty->ctrl_lock, flags);
532 * The session and fg pgrp references will be non-NULL if
533 * tiocsctty() is stealing the controlling tty
535 put_pid(tty->session);
537 tty->pgrp = get_pid(task_pgrp(current));
538 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
539 tty->session = get_pid(task_session(current));
540 if (current->signal->tty) {
541 tty_debug(tty, "current tty %s not NULL!!\n",
542 current->signal->tty->name);
543 tty_kref_put(current->signal->tty);
545 put_pid(current->signal->tty_old_pgrp);
546 current->signal->tty = tty_kref_get(tty);
547 current->signal->tty_old_pgrp = NULL;
550 static void proc_set_tty(struct tty_struct *tty)
552 spin_lock_irq(¤t->sighand->siglock);
554 spin_unlock_irq(¤t->sighand->siglock);
557 struct tty_struct *get_current_tty(void)
559 struct tty_struct *tty;
562 spin_lock_irqsave(¤t->sighand->siglock, flags);
563 tty = tty_kref_get(current->signal->tty);
564 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
567 EXPORT_SYMBOL_GPL(get_current_tty);
569 static void session_clear_tty(struct pid *session)
571 struct task_struct *p;
572 do_each_pid_task(session, PIDTYPE_SID, p) {
574 } while_each_pid_task(session, PIDTYPE_SID, p);
578 * tty_wakeup - request more data
581 * Internal and external helper for wakeups of tty. This function
582 * informs the line discipline if present that the driver is ready
583 * to receive more output data.
586 void tty_wakeup(struct tty_struct *tty)
588 struct tty_ldisc *ld;
590 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
591 ld = tty_ldisc_ref(tty);
593 if (ld->ops->write_wakeup)
594 ld->ops->write_wakeup(tty);
598 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
601 EXPORT_SYMBOL_GPL(tty_wakeup);
604 * tty_signal_session_leader - sends SIGHUP to session leader
605 * @tty controlling tty
606 * @exit_session if non-zero, signal all foreground group processes
608 * Send SIGHUP and SIGCONT to the session leader and its process group.
609 * Optionally, signal all processes in the foreground process group.
611 * Returns the number of processes in the session with this tty
612 * as their controlling terminal. This value is used to drop
613 * tty references for those processes.
615 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
617 struct task_struct *p;
619 struct pid *tty_pgrp = NULL;
621 read_lock(&tasklist_lock);
623 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
624 spin_lock_irq(&p->sighand->siglock);
625 if (p->signal->tty == tty) {
626 p->signal->tty = NULL;
627 /* We defer the dereferences outside fo
631 if (!p->signal->leader) {
632 spin_unlock_irq(&p->sighand->siglock);
635 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
636 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
637 put_pid(p->signal->tty_old_pgrp); /* A noop */
638 spin_lock(&tty->ctrl_lock);
639 tty_pgrp = get_pid(tty->pgrp);
641 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
642 spin_unlock(&tty->ctrl_lock);
643 spin_unlock_irq(&p->sighand->siglock);
644 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
646 read_unlock(&tasklist_lock);
650 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
658 * __tty_hangup - actual handler for hangup events
661 * This can be called by a "kworker" kernel thread. That is process
662 * synchronous but doesn't hold any locks, so we need to make sure we
663 * have the appropriate locks for what we're doing.
665 * The hangup event clears any pending redirections onto the hung up
666 * device. It ensures future writes will error and it does the needed
667 * line discipline hangup and signal delivery. The tty object itself
672 * redirect lock for undoing redirection
673 * file list lock for manipulating list of ttys
674 * tty_ldiscs_lock from called functions
675 * termios_rwsem resetting termios data
676 * tasklist_lock to walk task list for hangup event
677 * ->siglock to protect ->signal/->sighand
679 static void __tty_hangup(struct tty_struct *tty, int exit_session)
681 struct file *cons_filp = NULL;
682 struct file *filp, *f = NULL;
683 struct tty_file_private *priv;
684 int closecount = 0, n;
691 spin_lock(&redirect_lock);
692 if (redirect && file_tty(redirect) == tty) {
696 spin_unlock(&redirect_lock);
700 if (test_bit(TTY_HUPPED, &tty->flags)) {
705 /* inuse_filps is protected by the single tty lock,
706 this really needs to change if we want to flush the
707 workqueue with the lock held */
708 check_tty_count(tty, "tty_hangup");
710 spin_lock(&tty_files_lock);
711 /* This breaks for file handles being sent over AF_UNIX sockets ? */
712 list_for_each_entry(priv, &tty->tty_files, list) {
714 if (filp->f_op->write == redirected_tty_write)
716 if (filp->f_op->write != tty_write)
719 __tty_fasync(-1, filp, 0); /* can't block */
720 filp->f_op = &hung_up_tty_fops;
722 spin_unlock(&tty_files_lock);
724 refs = tty_signal_session_leader(tty, exit_session);
725 /* Account for the p->signal references we killed */
729 tty_ldisc_hangup(tty);
731 spin_lock_irq(&tty->ctrl_lock);
732 clear_bit(TTY_THROTTLED, &tty->flags);
733 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
734 put_pid(tty->session);
738 tty->ctrl_status = 0;
739 spin_unlock_irq(&tty->ctrl_lock);
742 * If one of the devices matches a console pointer, we
743 * cannot just call hangup() because that will cause
744 * tty->count and state->count to go out of sync.
745 * So we just call close() the right number of times.
749 for (n = 0; n < closecount; n++)
750 tty->ops->close(tty, cons_filp);
751 } else if (tty->ops->hangup)
752 tty->ops->hangup(tty);
754 * We don't want to have driver/ldisc interactions beyond
755 * the ones we did here. The driver layer expects no
756 * calls after ->hangup() from the ldisc side. However we
757 * can't yet guarantee all that.
759 set_bit(TTY_HUPPED, &tty->flags);
766 static void do_tty_hangup(struct work_struct *work)
768 struct tty_struct *tty =
769 container_of(work, struct tty_struct, hangup_work);
771 __tty_hangup(tty, 0);
775 * tty_hangup - trigger a hangup event
776 * @tty: tty to hangup
778 * A carrier loss (virtual or otherwise) has occurred on this like
779 * schedule a hangup sequence to run after this event.
782 void tty_hangup(struct tty_struct *tty)
784 tty_debug_hangup(tty, "\n");
785 schedule_work(&tty->hangup_work);
788 EXPORT_SYMBOL(tty_hangup);
791 * tty_vhangup - process vhangup
792 * @tty: tty to hangup
794 * The user has asked via system call for the terminal to be hung up.
795 * We do this synchronously so that when the syscall returns the process
796 * is complete. That guarantee is necessary for security reasons.
799 void tty_vhangup(struct tty_struct *tty)
801 tty_debug_hangup(tty, "\n");
802 __tty_hangup(tty, 0);
805 EXPORT_SYMBOL(tty_vhangup);
809 * tty_vhangup_self - process vhangup for own ctty
811 * Perform a vhangup on the current controlling tty
814 void tty_vhangup_self(void)
816 struct tty_struct *tty;
818 tty = get_current_tty();
826 * tty_vhangup_session - hangup session leader exit
827 * @tty: tty to hangup
829 * The session leader is exiting and hanging up its controlling terminal.
830 * Every process in the foreground process group is signalled SIGHUP.
832 * We do this synchronously so that when the syscall returns the process
833 * is complete. That guarantee is necessary for security reasons.
836 static void tty_vhangup_session(struct tty_struct *tty)
838 tty_debug_hangup(tty, "\n");
839 __tty_hangup(tty, 1);
843 * tty_hung_up_p - was tty hung up
844 * @filp: file pointer of tty
846 * Return true if the tty has been subject to a vhangup or a carrier
850 int tty_hung_up_p(struct file *filp)
852 return (filp->f_op == &hung_up_tty_fops);
855 EXPORT_SYMBOL(tty_hung_up_p);
858 * disassociate_ctty - disconnect controlling tty
859 * @on_exit: true if exiting so need to "hang up" the session
861 * This function is typically called only by the session leader, when
862 * it wants to disassociate itself from its controlling tty.
864 * It performs the following functions:
865 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
866 * (2) Clears the tty from being controlling the session
867 * (3) Clears the controlling tty for all processes in the
870 * The argument on_exit is set to 1 if called when a process is
871 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
874 * BTM is taken for hysterical raisins, and held when
875 * called from no_tty().
876 * tty_mutex is taken to protect tty
877 * ->siglock is taken to protect ->signal/->sighand
878 * tasklist_lock is taken to walk process list for sessions
879 * ->siglock is taken to protect ->signal/->sighand
882 void disassociate_ctty(int on_exit)
884 struct tty_struct *tty;
886 if (!current->signal->leader)
889 tty = get_current_tty();
891 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
892 tty_vhangup_session(tty);
894 struct pid *tty_pgrp = tty_get_pgrp(tty);
896 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
898 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
904 } else if (on_exit) {
905 struct pid *old_pgrp;
906 spin_lock_irq(¤t->sighand->siglock);
907 old_pgrp = current->signal->tty_old_pgrp;
908 current->signal->tty_old_pgrp = NULL;
909 spin_unlock_irq(¤t->sighand->siglock);
911 kill_pgrp(old_pgrp, SIGHUP, on_exit);
912 kill_pgrp(old_pgrp, SIGCONT, on_exit);
918 spin_lock_irq(¤t->sighand->siglock);
919 put_pid(current->signal->tty_old_pgrp);
920 current->signal->tty_old_pgrp = NULL;
922 tty = tty_kref_get(current->signal->tty);
925 spin_lock_irqsave(&tty->ctrl_lock, flags);
926 put_pid(tty->session);
930 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
933 tty_debug_hangup(tty, "no current tty\n");
935 spin_unlock_irq(¤t->sighand->siglock);
936 /* Now clear signal->tty under the lock */
937 read_lock(&tasklist_lock);
938 session_clear_tty(task_session(current));
939 read_unlock(&tasklist_lock);
944 * no_tty - Ensure the current process does not have a controlling tty
948 /* FIXME: Review locking here. The tty_lock never covered any race
949 between a new association and proc_clear_tty but possible we need
950 to protect against this anyway */
951 struct task_struct *tsk = current;
952 disassociate_ctty(0);
958 * stop_tty - propagate flow control
961 * Perform flow control to the driver. May be called
962 * on an already stopped device and will not re-call the driver
965 * This functionality is used by both the line disciplines for
966 * halting incoming flow and by the driver. It may therefore be
967 * called from any context, may be under the tty atomic_write_lock
974 void __stop_tty(struct tty_struct *tty)
983 void stop_tty(struct tty_struct *tty)
987 spin_lock_irqsave(&tty->flow_lock, flags);
989 spin_unlock_irqrestore(&tty->flow_lock, flags);
991 EXPORT_SYMBOL(stop_tty);
994 * start_tty - propagate flow control
997 * Start a tty that has been stopped if at all possible. If this
998 * tty was previous stopped and is now being started, the driver
999 * start method is invoked and the line discipline woken.
1005 void __start_tty(struct tty_struct *tty)
1007 if (!tty->stopped || tty->flow_stopped)
1010 if (tty->ops->start)
1011 tty->ops->start(tty);
1015 void start_tty(struct tty_struct *tty)
1017 unsigned long flags;
1019 spin_lock_irqsave(&tty->flow_lock, flags);
1021 spin_unlock_irqrestore(&tty->flow_lock, flags);
1023 EXPORT_SYMBOL(start_tty);
1025 static void tty_update_time(struct timespec *time)
1027 unsigned long sec = get_seconds();
1030 * We only care if the two values differ in anything other than the
1031 * lower three bits (i.e every 8 seconds). If so, then we can update
1032 * the time of the tty device, otherwise it could be construded as a
1033 * security leak to let userspace know the exact timing of the tty.
1035 if ((sec ^ time->tv_sec) & ~7)
1040 * tty_read - read method for tty device files
1041 * @file: pointer to tty file
1043 * @count: size of user buffer
1046 * Perform the read system call function on this terminal device. Checks
1047 * for hung up devices before calling the line discipline method.
1050 * Locks the line discipline internally while needed. Multiple
1051 * read calls may be outstanding in parallel.
1054 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1058 struct inode *inode = file_inode(file);
1059 struct tty_struct *tty = file_tty(file);
1060 struct tty_ldisc *ld;
1062 if (tty_paranoia_check(tty, inode, "tty_read"))
1064 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1067 /* We want to wait for the line discipline to sort out in this
1069 ld = tty_ldisc_ref_wait(tty);
1071 i = ld->ops->read(tty, file, buf, count);
1074 tty_ldisc_deref(ld);
1077 tty_update_time(&inode->i_atime);
1082 static void tty_write_unlock(struct tty_struct *tty)
1084 mutex_unlock(&tty->atomic_write_lock);
1085 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1088 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1090 if (!mutex_trylock(&tty->atomic_write_lock)) {
1093 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1094 return -ERESTARTSYS;
1100 * Split writes up in sane blocksizes to avoid
1101 * denial-of-service type attacks
1103 static inline ssize_t do_tty_write(
1104 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1105 struct tty_struct *tty,
1107 const char __user *buf,
1110 ssize_t ret, written = 0;
1113 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1118 * We chunk up writes into a temporary buffer. This
1119 * simplifies low-level drivers immensely, since they
1120 * don't have locking issues and user mode accesses.
1122 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1125 * The default chunk-size is 2kB, because the NTTY
1126 * layer has problems with bigger chunks. It will
1127 * claim to be able to handle more characters than
1130 * FIXME: This can probably go away now except that 64K chunks
1131 * are too likely to fail unless switched to vmalloc...
1134 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1139 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1140 if (tty->write_cnt < chunk) {
1141 unsigned char *buf_chunk;
1146 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1151 kfree(tty->write_buf);
1152 tty->write_cnt = chunk;
1153 tty->write_buf = buf_chunk;
1156 /* Do the write .. */
1158 size_t size = count;
1162 if (copy_from_user(tty->write_buf, buf, size))
1164 ret = write(tty, file, tty->write_buf, size);
1173 if (signal_pending(current))
1178 tty_update_time(&file_inode(file)->i_mtime);
1182 tty_write_unlock(tty);
1187 * tty_write_message - write a message to a certain tty, not just the console.
1188 * @tty: the destination tty_struct
1189 * @msg: the message to write
1191 * This is used for messages that need to be redirected to a specific tty.
1192 * We don't put it into the syslog queue right now maybe in the future if
1195 * We must still hold the BTM and test the CLOSING flag for the moment.
1198 void tty_write_message(struct tty_struct *tty, char *msg)
1201 mutex_lock(&tty->atomic_write_lock);
1203 if (tty->ops->write && tty->count > 0) {
1205 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 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1246 ld = tty_ldisc_ref_wait(tty);
1247 if (!ld->ops->write)
1250 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1251 tty_ldisc_deref(ld);
1255 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1256 size_t count, loff_t *ppos)
1258 struct file *p = NULL;
1260 spin_lock(&redirect_lock);
1262 p = get_file(redirect);
1263 spin_unlock(&redirect_lock);
1267 res = vfs_write(p, buf, count, &p->f_pos);
1271 return tty_write(file, buf, count, ppos);
1275 * tty_send_xchar - send priority character
1277 * Send a high priority character to the tty even if stopped
1279 * Locking: none for xchar method, write ordering for write method.
1282 int tty_send_xchar(struct tty_struct *tty, char ch)
1284 int was_stopped = tty->stopped;
1286 if (tty->ops->send_xchar) {
1287 tty->ops->send_xchar(tty, ch);
1291 if (tty_write_lock(tty, 0) < 0)
1292 return -ERESTARTSYS;
1296 tty->ops->write(tty, &ch, 1);
1299 tty_write_unlock(tty);
1303 static char ptychar[] = "pqrstuvwxyzabcde";
1306 * pty_line_name - generate name for a pty
1307 * @driver: the tty driver in use
1308 * @index: the minor number
1309 * @p: output buffer of at least 6 bytes
1311 * Generate a name from a driver reference and write it to the output
1316 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1318 int i = index + driver->name_base;
1319 /* ->name is initialized to "ttyp", but "tty" is expected */
1320 sprintf(p, "%s%c%x",
1321 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1322 ptychar[i >> 4 & 0xf], i & 0xf);
1326 * tty_line_name - generate name for a tty
1327 * @driver: the tty driver in use
1328 * @index: the minor number
1329 * @p: output buffer of at least 7 bytes
1331 * Generate a name from a driver reference and write it to the output
1336 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1338 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1339 return sprintf(p, "%s", driver->name);
1341 return sprintf(p, "%s%d", driver->name,
1342 index + driver->name_base);
1346 * tty_driver_lookup_tty() - find an existing tty, if any
1347 * @driver: the driver for the tty
1348 * @idx: the minor number
1350 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1351 * driver lookup() method returns an error.
1353 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1355 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1356 struct inode *inode, int idx)
1358 struct tty_struct *tty;
1360 if (driver->ops->lookup)
1361 tty = driver->ops->lookup(driver, inode, idx);
1363 tty = driver->ttys[idx];
1371 * tty_init_termios - helper for termios setup
1372 * @tty: the tty to set up
1374 * Initialise the termios structures for this tty. Thus runs under
1375 * the tty_mutex currently so we can be relaxed about ordering.
1378 int tty_init_termios(struct tty_struct *tty)
1380 struct ktermios *tp;
1381 int idx = tty->index;
1383 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1384 tty->termios = tty->driver->init_termios;
1386 /* Check for lazy saved data */
1387 tp = tty->driver->termios[idx];
1391 tty->termios = tty->driver->init_termios;
1393 /* Compatibility until drivers always set this */
1394 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1395 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1398 EXPORT_SYMBOL_GPL(tty_init_termios);
1400 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1402 int ret = tty_init_termios(tty);
1406 tty_driver_kref_get(driver);
1408 driver->ttys[tty->index] = tty;
1411 EXPORT_SYMBOL_GPL(tty_standard_install);
1414 * tty_driver_install_tty() - install a tty entry in the driver
1415 * @driver: the driver for the tty
1418 * Install a tty object into the driver tables. The tty->index field
1419 * will be set by the time this is called. This method is responsible
1420 * for ensuring any need additional structures are allocated and
1423 * Locking: tty_mutex for now
1425 static int tty_driver_install_tty(struct tty_driver *driver,
1426 struct tty_struct *tty)
1428 return driver->ops->install ? driver->ops->install(driver, tty) :
1429 tty_standard_install(driver, tty);
1433 * tty_driver_remove_tty() - remove a tty from the driver tables
1434 * @driver: the driver for the tty
1435 * @idx: the minor number
1437 * Remvoe a tty object from the driver tables. The tty->index field
1438 * will be set by the time this is called.
1440 * Locking: tty_mutex for now
1442 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1444 if (driver->ops->remove)
1445 driver->ops->remove(driver, tty);
1447 driver->ttys[tty->index] = NULL;
1451 * tty_reopen() - fast re-open of an open tty
1452 * @tty - the tty to open
1454 * Return 0 on success, -errno on error.
1455 * Re-opens on master ptys are not allowed and return -EIO.
1457 * Locking: Caller must hold tty_lock
1459 static int tty_reopen(struct tty_struct *tty)
1461 struct tty_driver *driver = tty->driver;
1466 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1467 driver->subtype == PTY_TYPE_MASTER)
1470 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1475 WARN_ON(!tty->ldisc);
1481 * tty_init_dev - initialise a tty device
1482 * @driver: tty driver we are opening a device on
1483 * @idx: device index
1484 * @ret_tty: returned tty structure
1486 * Prepare a tty device. This may not be a "new" clean device but
1487 * could also be an active device. The pty drivers require special
1488 * handling because of this.
1491 * The function is called under the tty_mutex, which
1492 * protects us from the tty struct or driver itself going away.
1494 * On exit the tty device has the line discipline attached and
1495 * a reference count of 1. If a pair was created for pty/tty use
1496 * and the other was a pty master then it too has a reference count of 1.
1498 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1499 * failed open. The new code protects the open with a mutex, so it's
1500 * really quite straightforward. The mutex locking can probably be
1501 * relaxed for the (most common) case of reopening a tty.
1504 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1506 struct tty_struct *tty;
1510 * First time open is complex, especially for PTY devices.
1511 * This code guarantees that either everything succeeds and the
1512 * TTY is ready for operation, or else the table slots are vacated
1513 * and the allocated memory released. (Except that the termios
1514 * and locked termios may be retained.)
1517 if (!try_module_get(driver->owner))
1518 return ERR_PTR(-ENODEV);
1520 tty = alloc_tty_struct(driver, idx);
1523 goto err_module_put;
1527 retval = tty_driver_install_tty(driver, tty);
1529 goto err_deinit_tty;
1532 tty->port = driver->ports[idx];
1534 WARN_RATELIMIT(!tty->port,
1535 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1536 __func__, tty->driver->name);
1538 tty->port->itty = tty;
1541 * Structures all installed ... call the ldisc open routines.
1542 * If we fail here just call release_tty to clean up. No need
1543 * to decrement the use counts, as release_tty doesn't care.
1545 retval = tty_ldisc_setup(tty, tty->link);
1547 goto err_release_tty;
1548 /* Return the tty locked so that it cannot vanish under the caller */
1553 deinitialize_tty_struct(tty);
1554 free_tty_struct(tty);
1556 module_put(driver->owner);
1557 return ERR_PTR(retval);
1559 /* call the tty release_tty routine to clean out this slot */
1562 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1563 "clearing slot %d\n", idx);
1564 release_tty(tty, idx);
1565 return ERR_PTR(retval);
1568 void tty_free_termios(struct tty_struct *tty)
1570 struct ktermios *tp;
1571 int idx = tty->index;
1573 /* If the port is going to reset then it has no termios to save */
1574 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1577 /* Stash the termios data */
1578 tp = tty->driver->termios[idx];
1580 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1582 pr_warn("tty: no memory to save termios state.\n");
1585 tty->driver->termios[idx] = tp;
1589 EXPORT_SYMBOL(tty_free_termios);
1592 * tty_flush_works - flush all works of a tty/pty pair
1593 * @tty: tty device to flush works for (or either end of a pty pair)
1595 * Sync flush all works belonging to @tty (and the 'other' tty).
1597 static void tty_flush_works(struct tty_struct *tty)
1599 flush_work(&tty->SAK_work);
1600 flush_work(&tty->hangup_work);
1602 flush_work(&tty->link->SAK_work);
1603 flush_work(&tty->link->hangup_work);
1608 * release_one_tty - release tty structure memory
1609 * @kref: kref of tty we are obliterating
1611 * Releases memory associated with a tty structure, and clears out the
1612 * driver table slots. This function is called when a device is no longer
1613 * in use. It also gets called when setup of a device fails.
1616 * takes the file list lock internally when working on the list
1617 * of ttys that the driver keeps.
1619 * This method gets called from a work queue so that the driver private
1620 * cleanup ops can sleep (needed for USB at least)
1622 static void release_one_tty(struct work_struct *work)
1624 struct tty_struct *tty =
1625 container_of(work, struct tty_struct, hangup_work);
1626 struct tty_driver *driver = tty->driver;
1627 struct module *owner = driver->owner;
1629 if (tty->ops->cleanup)
1630 tty->ops->cleanup(tty);
1633 tty_driver_kref_put(driver);
1636 spin_lock(&tty_files_lock);
1637 list_del_init(&tty->tty_files);
1638 spin_unlock(&tty_files_lock);
1641 put_pid(tty->session);
1642 free_tty_struct(tty);
1645 static void queue_release_one_tty(struct kref *kref)
1647 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1649 /* The hangup queue is now free so we can reuse it rather than
1650 waste a chunk of memory for each port */
1651 INIT_WORK(&tty->hangup_work, release_one_tty);
1652 schedule_work(&tty->hangup_work);
1656 * tty_kref_put - release a tty kref
1659 * Release a reference to a tty device and if need be let the kref
1660 * layer destruct the object for us
1663 void tty_kref_put(struct tty_struct *tty)
1666 kref_put(&tty->kref, queue_release_one_tty);
1668 EXPORT_SYMBOL(tty_kref_put);
1671 * release_tty - release tty structure memory
1673 * Release both @tty and a possible linked partner (think pty pair),
1674 * and decrement the refcount of the backing module.
1678 * takes the file list lock internally when working on the list
1679 * of ttys that the driver keeps.
1682 static void release_tty(struct tty_struct *tty, int idx)
1684 /* This should always be true but check for the moment */
1685 WARN_ON(tty->index != idx);
1686 WARN_ON(!mutex_is_locked(&tty_mutex));
1687 if (tty->ops->shutdown)
1688 tty->ops->shutdown(tty);
1689 tty_free_termios(tty);
1690 tty_driver_remove_tty(tty->driver, tty);
1691 tty->port->itty = NULL;
1693 tty->link->port->itty = NULL;
1694 cancel_work_sync(&tty->port->buf.work);
1696 tty_kref_put(tty->link);
1701 * tty_release_checks - check a tty before real release
1702 * @tty: tty to check
1703 * @o_tty: link of @tty (if any)
1704 * @idx: index of the tty
1706 * Performs some paranoid checking before true release of the @tty.
1707 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1709 static int tty_release_checks(struct tty_struct *tty, int idx)
1711 #ifdef TTY_PARANOIA_CHECK
1712 if (idx < 0 || idx >= tty->driver->num) {
1713 tty_debug(tty, "bad idx %d\n", idx);
1717 /* not much to check for devpts */
1718 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1721 if (tty != tty->driver->ttys[idx]) {
1722 tty_debug(tty, "bad driver table[%d] = %p\n",
1723 idx, tty->driver->ttys[idx]);
1726 if (tty->driver->other) {
1727 struct tty_struct *o_tty = tty->link;
1729 if (o_tty != tty->driver->other->ttys[idx]) {
1730 tty_debug(tty, "bad other table[%d] = %p\n",
1731 idx, tty->driver->other->ttys[idx]);
1734 if (o_tty->link != tty) {
1735 tty_debug(tty, "bad link = %p\n", o_tty->link);
1744 * tty_release - vfs callback for close
1745 * @inode: inode of tty
1746 * @filp: file pointer for handle to tty
1748 * Called the last time each file handle is closed that references
1749 * this tty. There may however be several such references.
1752 * Takes bkl. See tty_release_dev
1754 * Even releasing the tty structures is a tricky business.. We have
1755 * to be very careful that the structures are all released at the
1756 * same time, as interrupts might otherwise get the wrong pointers.
1758 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1759 * lead to double frees or releasing memory still in use.
1762 int tty_release(struct inode *inode, struct file *filp)
1764 struct tty_struct *tty = file_tty(filp);
1765 struct tty_struct *o_tty = NULL;
1766 int do_sleep, final;
1771 if (tty_paranoia_check(tty, inode, __func__))
1775 check_tty_count(tty, __func__);
1777 __tty_fasync(-1, filp, 0);
1780 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1781 tty->driver->subtype == PTY_TYPE_MASTER)
1784 if (tty_release_checks(tty, idx)) {
1789 tty_debug_hangup(tty, "(tty count=%d)...\n", tty->count);
1791 if (tty->ops->close)
1792 tty->ops->close(tty, filp);
1794 /* If tty is pty master, lock the slave pty (stable lock order) */
1795 tty_lock_slave(o_tty);
1798 * Sanity check: if tty->count is going to zero, there shouldn't be
1799 * any waiters on tty->read_wait or tty->write_wait. We test the
1800 * wait queues and kick everyone out _before_ actually starting to
1801 * close. This ensures that we won't block while releasing the tty
1804 * The test for the o_tty closing is necessary, since the master and
1805 * slave sides may close in any order. If the slave side closes out
1806 * first, its count will be one, since the master side holds an open.
1807 * Thus this test wouldn't be triggered at the time the slave closed,
1813 if (tty->count <= 1) {
1814 if (waitqueue_active(&tty->read_wait)) {
1815 wake_up_poll(&tty->read_wait, POLLIN);
1818 if (waitqueue_active(&tty->write_wait)) {
1819 wake_up_poll(&tty->write_wait, POLLOUT);
1823 if (o_tty && o_tty->count <= 1) {
1824 if (waitqueue_active(&o_tty->read_wait)) {
1825 wake_up_poll(&o_tty->read_wait, POLLIN);
1828 if (waitqueue_active(&o_tty->write_wait)) {
1829 wake_up_poll(&o_tty->write_wait, POLLOUT);
1838 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1839 __func__, tty_name(tty));
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 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1851 __func__, o_tty->count, tty_name(o_tty));
1855 if (--tty->count < 0) {
1856 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1857 __func__, tty->count, tty_name(tty));
1862 * We've decremented tty->count, so we need to remove this file
1863 * descriptor off the tty->tty_files list; this serves two
1865 * - check_tty_count sees the correct number of file descriptors
1866 * associated with this tty.
1867 * - do_tty_hangup no longer sees this file descriptor as
1868 * something that needs to be handled for hangups.
1873 * Perform some housekeeping before deciding whether to return.
1875 * If _either_ side is closing, make sure there aren't any
1876 * processes that still think tty or o_tty is their controlling
1880 read_lock(&tasklist_lock);
1881 session_clear_tty(tty->session);
1883 session_clear_tty(o_tty->session);
1884 read_unlock(&tasklist_lock);
1887 /* check whether both sides are closing ... */
1888 final = !tty->count && !(o_tty && o_tty->count);
1890 tty_unlock_slave(o_tty);
1893 /* At this point, the tty->count == 0 should ensure a dead tty
1894 cannot be re-opened by a racing opener */
1899 tty_debug_hangup(tty, "final close\n");
1901 * Ask the line discipline code to release its structures
1903 tty_ldisc_release(tty);
1905 /* Wait for pending work before tty destruction commmences */
1906 tty_flush_works(tty);
1908 tty_debug_hangup(tty, "freeing structure...\n");
1910 * The release_tty function takes care of the details of clearing
1911 * the slots and preserving the termios structure. The tty_unlock_pair
1912 * should be safe as we keep a kref while the tty is locked (so the
1913 * unlock never unlocks a freed tty).
1915 mutex_lock(&tty_mutex);
1916 release_tty(tty, idx);
1917 mutex_unlock(&tty_mutex);
1923 * tty_open_current_tty - get locked tty of current task
1924 * @device: device number
1925 * @filp: file pointer to tty
1926 * @return: locked tty of the current task iff @device is /dev/tty
1928 * Performs a re-open of the current task's controlling tty.
1930 * We cannot return driver and index like for the other nodes because
1931 * devpts will not work then. It expects inodes to be from devpts FS.
1933 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1935 struct tty_struct *tty;
1938 if (device != MKDEV(TTYAUX_MAJOR, 0))
1941 tty = get_current_tty();
1943 return ERR_PTR(-ENXIO);
1945 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1948 tty_kref_put(tty); /* safe to drop the kref now */
1950 retval = tty_reopen(tty);
1953 tty = ERR_PTR(retval);
1959 * tty_lookup_driver - lookup a tty driver for a given device file
1960 * @device: device number
1961 * @filp: file pointer to tty
1962 * @noctty: set if the device should not become a controlling tty
1963 * @index: index for the device in the @return driver
1964 * @return: driver for this inode (with increased refcount)
1966 * If @return is not erroneous, the caller is responsible to decrement the
1967 * refcount by tty_driver_kref_put.
1969 * Locking: tty_mutex protects get_tty_driver
1971 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1972 int *noctty, int *index)
1974 struct tty_driver *driver;
1978 case MKDEV(TTY_MAJOR, 0): {
1979 extern struct tty_driver *console_driver;
1980 driver = tty_driver_kref_get(console_driver);
1981 *index = fg_console;
1986 case MKDEV(TTYAUX_MAJOR, 1): {
1987 struct tty_driver *console_driver = console_device(index);
1988 if (console_driver) {
1989 driver = tty_driver_kref_get(console_driver);
1991 /* Don't let /dev/console block */
1992 filp->f_flags |= O_NONBLOCK;
1997 return ERR_PTR(-ENODEV);
2000 driver = get_tty_driver(device, index);
2002 return ERR_PTR(-ENODEV);
2009 * tty_open - open a tty device
2010 * @inode: inode of device file
2011 * @filp: file pointer to tty
2013 * tty_open and tty_release keep up the tty count that contains the
2014 * number of opens done on a tty. We cannot use the inode-count, as
2015 * different inodes might point to the same tty.
2017 * Open-counting is needed for pty masters, as well as for keeping
2018 * track of serial lines: DTR is dropped when the last close happens.
2019 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2021 * The termios state of a pty is reset on first open so that
2022 * settings don't persist across reuse.
2024 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2025 * tty->count should protect the rest.
2026 * ->siglock protects ->signal/->sighand
2028 * Note: the tty_unlock/lock cases without a ref are only safe due to
2032 static int tty_open(struct inode *inode, struct file *filp)
2034 struct tty_struct *tty;
2036 struct tty_driver *driver = NULL;
2038 dev_t device = inode->i_rdev;
2039 unsigned saved_flags = filp->f_flags;
2041 nonseekable_open(inode, filp);
2044 retval = tty_alloc_file(filp);
2048 noctty = filp->f_flags & O_NOCTTY;
2052 tty = tty_open_current_tty(device, filp);
2054 mutex_lock(&tty_mutex);
2055 driver = tty_lookup_driver(device, filp, &noctty, &index);
2056 if (IS_ERR(driver)) {
2057 retval = PTR_ERR(driver);
2061 /* check whether we're reopening an existing tty */
2062 tty = tty_driver_lookup_tty(driver, inode, index);
2064 retval = PTR_ERR(tty);
2069 mutex_unlock(&tty_mutex);
2071 /* safe to drop the kref from tty_driver_lookup_tty() */
2073 retval = tty_reopen(tty);
2076 tty = ERR_PTR(retval);
2078 } else { /* Returns with the tty_lock held for now */
2079 tty = tty_init_dev(driver, index);
2080 mutex_unlock(&tty_mutex);
2083 tty_driver_kref_put(driver);
2087 retval = PTR_ERR(tty);
2091 tty_add_file(tty, filp);
2093 check_tty_count(tty, __func__);
2094 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2095 tty->driver->subtype == PTY_TYPE_MASTER)
2098 tty_debug_hangup(tty, "(tty count=%d)\n", tty->count);
2101 retval = tty->ops->open(tty, filp);
2104 filp->f_flags = saved_flags;
2107 tty_debug_hangup(tty, "error %d, releasing...\n", retval);
2109 tty_unlock(tty); /* need to call tty_release without BTM */
2110 tty_release(inode, filp);
2111 if (retval != -ERESTARTSYS)
2114 if (signal_pending(current))
2119 * Need to reset f_op in case a hangup happened.
2121 if (tty_hung_up_p(filp))
2122 filp->f_op = &tty_fops;
2125 clear_bit(TTY_HUPPED, &tty->flags);
2128 read_lock(&tasklist_lock);
2129 spin_lock_irq(¤t->sighand->siglock);
2131 current->signal->leader &&
2132 !current->signal->tty &&
2133 tty->session == NULL) {
2135 * Don't let a process that only has write access to the tty
2136 * obtain the privileges associated with having a tty as
2137 * controlling terminal (being able to reopen it with full
2138 * access through /dev/tty, being able to perform pushback).
2139 * Many distributions set the group of all ttys to "tty" and
2140 * grant write-only access to all terminals for setgid tty
2141 * binaries, which should not imply full privileges on all ttys.
2143 * This could theoretically break old code that performs open()
2144 * on a write-only file descriptor. In that case, it might be
2145 * necessary to also permit this if
2146 * inode_permission(inode, MAY_READ) == 0.
2148 if (filp->f_mode & FMODE_READ)
2149 __proc_set_tty(tty);
2151 spin_unlock_irq(¤t->sighand->siglock);
2152 read_unlock(&tasklist_lock);
2156 mutex_unlock(&tty_mutex);
2157 /* after locks to avoid deadlock */
2158 if (!IS_ERR_OR_NULL(driver))
2159 tty_driver_kref_put(driver);
2161 tty_free_file(filp);
2168 * tty_poll - check tty status
2169 * @filp: file being polled
2170 * @wait: poll wait structures to update
2172 * Call the line discipline polling method to obtain the poll
2173 * status of the device.
2175 * Locking: locks called line discipline but ldisc poll method
2176 * may be re-entered freely by other callers.
2179 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2181 struct tty_struct *tty = file_tty(filp);
2182 struct tty_ldisc *ld;
2185 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2188 ld = tty_ldisc_ref_wait(tty);
2190 ret = ld->ops->poll(tty, filp, wait);
2191 tty_ldisc_deref(ld);
2195 static int __tty_fasync(int fd, struct file *filp, int on)
2197 struct tty_struct *tty = file_tty(filp);
2198 struct tty_ldisc *ldisc;
2199 unsigned long flags;
2202 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2205 retval = fasync_helper(fd, filp, on, &tty->fasync);
2209 ldisc = tty_ldisc_ref(tty);
2211 if (ldisc->ops->fasync)
2212 ldisc->ops->fasync(tty, on);
2213 tty_ldisc_deref(ldisc);
2220 spin_lock_irqsave(&tty->ctrl_lock, flags);
2223 type = PIDTYPE_PGID;
2225 pid = task_pid(current);
2229 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2230 __f_setown(filp, pid, type, 0);
2238 static int tty_fasync(int fd, struct file *filp, int on)
2240 struct tty_struct *tty = file_tty(filp);
2244 retval = __tty_fasync(fd, filp, on);
2251 * tiocsti - fake input character
2252 * @tty: tty to fake input into
2253 * @p: pointer to character
2255 * Fake input to a tty device. Does the necessary locking and
2258 * FIXME: does not honour flow control ??
2261 * Called functions take tty_ldiscs_lock
2262 * current->signal->tty check is safe without locks
2264 * FIXME: may race normal receive processing
2267 static int tiocsti(struct tty_struct *tty, char __user *p)
2270 struct tty_ldisc *ld;
2272 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2274 if (get_user(ch, p))
2276 tty_audit_tiocsti(tty, ch);
2277 ld = tty_ldisc_ref_wait(tty);
2278 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2279 tty_ldisc_deref(ld);
2284 * tiocgwinsz - implement window query ioctl
2286 * @arg: user buffer for result
2288 * Copies the kernel idea of the window size into the user buffer.
2290 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2294 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2298 mutex_lock(&tty->winsize_mutex);
2299 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2300 mutex_unlock(&tty->winsize_mutex);
2302 return err ? -EFAULT: 0;
2306 * tty_do_resize - resize event
2307 * @tty: tty being resized
2308 * @rows: rows (character)
2309 * @cols: cols (character)
2311 * Update the termios variables and send the necessary signals to
2312 * peform a terminal resize correctly
2315 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2320 mutex_lock(&tty->winsize_mutex);
2321 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2324 /* Signal the foreground process group */
2325 pgrp = tty_get_pgrp(tty);
2327 kill_pgrp(pgrp, SIGWINCH, 1);
2332 mutex_unlock(&tty->winsize_mutex);
2335 EXPORT_SYMBOL(tty_do_resize);
2338 * tiocswinsz - implement window size set ioctl
2339 * @tty; tty side of tty
2340 * @arg: user buffer for result
2342 * Copies the user idea of the window size to the kernel. Traditionally
2343 * this is just advisory information but for the Linux console it
2344 * actually has driver level meaning and triggers a VC resize.
2347 * Driver dependent. The default do_resize method takes the
2348 * tty termios mutex and ctrl_lock. The console takes its own lock
2349 * then calls into the default method.
2352 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2354 struct winsize tmp_ws;
2355 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2358 if (tty->ops->resize)
2359 return tty->ops->resize(tty, &tmp_ws);
2361 return tty_do_resize(tty, &tmp_ws);
2365 * tioccons - allow admin to move logical console
2366 * @file: the file to become console
2368 * Allow the administrator to move the redirected console device
2370 * Locking: uses redirect_lock to guard the redirect information
2373 static int tioccons(struct file *file)
2375 if (!capable(CAP_SYS_ADMIN))
2377 if (file->f_op->write == redirected_tty_write) {
2379 spin_lock(&redirect_lock);
2382 spin_unlock(&redirect_lock);
2387 spin_lock(&redirect_lock);
2389 spin_unlock(&redirect_lock);
2392 redirect = get_file(file);
2393 spin_unlock(&redirect_lock);
2398 * fionbio - non blocking ioctl
2399 * @file: file to set blocking value
2400 * @p: user parameter
2402 * Historical tty interfaces had a blocking control ioctl before
2403 * the generic functionality existed. This piece of history is preserved
2404 * in the expected tty API of posix OS's.
2406 * Locking: none, the open file handle ensures it won't go away.
2409 static int fionbio(struct file *file, int __user *p)
2413 if (get_user(nonblock, p))
2416 spin_lock(&file->f_lock);
2418 file->f_flags |= O_NONBLOCK;
2420 file->f_flags &= ~O_NONBLOCK;
2421 spin_unlock(&file->f_lock);
2426 * tiocsctty - set controlling tty
2427 * @tty: tty structure
2428 * @arg: user argument
2430 * This ioctl is used to manage job control. It permits a session
2431 * leader to set this tty as the controlling tty for the session.
2434 * Takes tty_lock() to serialize proc_set_tty() for this tty
2435 * Takes tasklist_lock internally to walk sessions
2436 * Takes ->siglock() when updating signal->tty
2439 static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2444 read_lock(&tasklist_lock);
2446 if (current->signal->leader && (task_session(current) == tty->session))
2450 * The process must be a session leader and
2451 * not have a controlling tty already.
2453 if (!current->signal->leader || current->signal->tty) {
2460 * This tty is already the controlling
2461 * tty for another session group!
2463 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2467 session_clear_tty(tty->session);
2474 /* See the comment in tty_open(). */
2475 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2482 read_unlock(&tasklist_lock);
2488 * tty_get_pgrp - return a ref counted pgrp pid
2491 * Returns a refcounted instance of the pid struct for the process
2492 * group controlling the tty.
2495 struct pid *tty_get_pgrp(struct tty_struct *tty)
2497 unsigned long flags;
2500 spin_lock_irqsave(&tty->ctrl_lock, flags);
2501 pgrp = get_pid(tty->pgrp);
2502 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2506 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2509 * This checks not only the pgrp, but falls back on the pid if no
2510 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2513 * The caller must hold rcu lock or the tasklist lock.
2515 static struct pid *session_of_pgrp(struct pid *pgrp)
2517 struct task_struct *p;
2518 struct pid *sid = NULL;
2520 p = pid_task(pgrp, PIDTYPE_PGID);
2522 p = pid_task(pgrp, PIDTYPE_PID);
2524 sid = task_session(p);
2530 * tiocgpgrp - get process group
2531 * @tty: tty passed by user
2532 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2535 * Obtain the process group of the tty. If there is no process group
2538 * Locking: none. Reference to current->signal->tty is safe.
2541 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2546 * (tty == real_tty) is a cheap way of
2547 * testing if the tty is NOT a master pty.
2549 if (tty == real_tty && current->signal->tty != real_tty)
2551 pid = tty_get_pgrp(real_tty);
2552 ret = put_user(pid_vnr(pid), p);
2558 * tiocspgrp - attempt to set process group
2559 * @tty: tty passed by user
2560 * @real_tty: tty side device matching tty passed by user
2563 * Set the process group of the tty to the session passed. Only
2564 * permitted where the tty session is our session.
2566 * Locking: RCU, ctrl lock
2569 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2573 int retval = tty_check_change(real_tty);
2574 unsigned long flags;
2580 if (!current->signal->tty ||
2581 (current->signal->tty != real_tty) ||
2582 (real_tty->session != task_session(current)))
2584 if (get_user(pgrp_nr, p))
2589 pgrp = find_vpid(pgrp_nr);
2594 if (session_of_pgrp(pgrp) != task_session(current))
2597 spin_lock_irqsave(&tty->ctrl_lock, flags);
2598 put_pid(real_tty->pgrp);
2599 real_tty->pgrp = get_pid(pgrp);
2600 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2607 * tiocgsid - get session id
2608 * @tty: tty passed by user
2609 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2610 * @p: pointer to returned session id
2612 * Obtain the session id of the tty. If there is no session
2615 * Locking: none. Reference to current->signal->tty is safe.
2618 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2621 * (tty == real_tty) is a cheap way of
2622 * testing if the tty is NOT a master pty.
2624 if (tty == real_tty && current->signal->tty != real_tty)
2626 if (!real_tty->session)
2628 return put_user(pid_vnr(real_tty->session), p);
2632 * tiocsetd - set line discipline
2634 * @p: pointer to user data
2636 * Set the line discipline according to user request.
2638 * Locking: see tty_set_ldisc, this function is just a helper
2641 static int tiocsetd(struct tty_struct *tty, int __user *p)
2646 if (get_user(ldisc, p))
2649 ret = tty_set_ldisc(tty, ldisc);
2655 * send_break - performed time break
2656 * @tty: device to break on
2657 * @duration: timeout in mS
2659 * Perform a timed break on hardware that lacks its own driver level
2660 * timed break functionality.
2663 * atomic_write_lock serializes
2667 static int send_break(struct tty_struct *tty, unsigned int duration)
2671 if (tty->ops->break_ctl == NULL)
2674 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2675 retval = tty->ops->break_ctl(tty, duration);
2677 /* Do the work ourselves */
2678 if (tty_write_lock(tty, 0) < 0)
2680 retval = tty->ops->break_ctl(tty, -1);
2683 if (!signal_pending(current))
2684 msleep_interruptible(duration);
2685 retval = tty->ops->break_ctl(tty, 0);
2687 tty_write_unlock(tty);
2688 if (signal_pending(current))
2695 * tty_tiocmget - get modem status
2697 * @file: user file pointer
2698 * @p: pointer to result
2700 * Obtain the modem status bits from the tty driver if the feature
2701 * is supported. Return -EINVAL if it is not available.
2703 * Locking: none (up to the driver)
2706 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2708 int retval = -EINVAL;
2710 if (tty->ops->tiocmget) {
2711 retval = tty->ops->tiocmget(tty);
2714 retval = put_user(retval, p);
2720 * tty_tiocmset - set modem status
2722 * @cmd: command - clear bits, set bits or set all
2723 * @p: pointer to desired bits
2725 * Set the modem status bits from the tty driver if the feature
2726 * is supported. Return -EINVAL if it is not available.
2728 * Locking: none (up to the driver)
2731 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2735 unsigned int set, clear, val;
2737 if (tty->ops->tiocmset == NULL)
2740 retval = get_user(val, p);
2756 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2757 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2758 return tty->ops->tiocmset(tty, set, clear);
2761 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2763 int retval = -EINVAL;
2764 struct serial_icounter_struct icount;
2765 memset(&icount, 0, sizeof(icount));
2766 if (tty->ops->get_icount)
2767 retval = tty->ops->get_icount(tty, &icount);
2770 if (copy_to_user(arg, &icount, sizeof(icount)))
2775 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2777 static DEFINE_RATELIMIT_STATE(depr_flags,
2778 DEFAULT_RATELIMIT_INTERVAL,
2779 DEFAULT_RATELIMIT_BURST);
2780 char comm[TASK_COMM_LEN];
2783 if (get_user(flags, &ss->flags))
2786 flags &= ASYNC_DEPRECATED;
2788 if (flags && __ratelimit(&depr_flags))
2789 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2790 __func__, get_task_comm(comm, current), flags);
2794 * if pty, return the slave side (real_tty)
2795 * otherwise, return self
2797 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2799 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2800 tty->driver->subtype == PTY_TYPE_MASTER)
2806 * Split this up, as gcc can choke on it otherwise..
2808 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2810 struct tty_struct *tty = file_tty(file);
2811 struct tty_struct *real_tty;
2812 void __user *p = (void __user *)arg;
2814 struct tty_ldisc *ld;
2816 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2819 real_tty = tty_pair_get_tty(tty);
2822 * Factor out some common prep work
2830 retval = tty_check_change(tty);
2833 if (cmd != TIOCCBRK) {
2834 tty_wait_until_sent(tty, 0);
2835 if (signal_pending(current))
2846 return tiocsti(tty, p);
2848 return tiocgwinsz(real_tty, p);
2850 return tiocswinsz(real_tty, p);
2852 return real_tty != tty ? -EINVAL : tioccons(file);
2854 return fionbio(file, p);
2856 set_bit(TTY_EXCLUSIVE, &tty->flags);
2859 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2863 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2864 return put_user(excl, (int __user *)p);
2867 if (current->signal->tty != tty)
2872 return tiocsctty(tty, file, arg);
2874 return tiocgpgrp(tty, real_tty, p);
2876 return tiocspgrp(tty, real_tty, p);
2878 return tiocgsid(tty, real_tty, p);
2880 return put_user(tty->ldisc->ops->num, (int __user *)p);
2882 return tiocsetd(tty, p);
2884 if (!capable(CAP_SYS_ADMIN))
2890 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2891 return put_user(ret, (unsigned int __user *)p);
2896 case TIOCSBRK: /* Turn break on, unconditionally */
2897 if (tty->ops->break_ctl)
2898 return tty->ops->break_ctl(tty, -1);
2900 case TIOCCBRK: /* Turn break off, unconditionally */
2901 if (tty->ops->break_ctl)
2902 return tty->ops->break_ctl(tty, 0);
2904 case TCSBRK: /* SVID version: non-zero arg --> no break */
2905 /* non-zero arg means wait for all output data
2906 * to be sent (performed above) but don't send break.
2907 * This is used by the tcdrain() termios function.
2910 return send_break(tty, 250);
2912 case TCSBRKP: /* support for POSIX tcsendbreak() */
2913 return send_break(tty, arg ? arg*100 : 250);
2916 return tty_tiocmget(tty, p);
2920 return tty_tiocmset(tty, cmd, p);
2922 retval = tty_tiocgicount(tty, p);
2923 /* For the moment allow fall through to the old method */
2924 if (retval != -EINVAL)
2931 /* flush tty buffer and allow ldisc to process ioctl */
2932 tty_buffer_flush(tty, NULL);
2937 tty_warn_deprecated_flags(p);
2940 if (tty->ops->ioctl) {
2941 retval = tty->ops->ioctl(tty, cmd, arg);
2942 if (retval != -ENOIOCTLCMD)
2945 ld = tty_ldisc_ref_wait(tty);
2947 if (ld->ops->ioctl) {
2948 retval = ld->ops->ioctl(tty, file, cmd, arg);
2949 if (retval == -ENOIOCTLCMD)
2952 tty_ldisc_deref(ld);
2956 #ifdef CONFIG_COMPAT
2957 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2960 struct tty_struct *tty = file_tty(file);
2961 struct tty_ldisc *ld;
2962 int retval = -ENOIOCTLCMD;
2964 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2967 if (tty->ops->compat_ioctl) {
2968 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2969 if (retval != -ENOIOCTLCMD)
2973 ld = tty_ldisc_ref_wait(tty);
2974 if (ld->ops->compat_ioctl)
2975 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2977 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2978 tty_ldisc_deref(ld);
2984 static int this_tty(const void *t, struct file *file, unsigned fd)
2986 if (likely(file->f_op->read != tty_read))
2988 return file_tty(file) != t ? 0 : fd + 1;
2992 * This implements the "Secure Attention Key" --- the idea is to
2993 * prevent trojan horses by killing all processes associated with this
2994 * tty when the user hits the "Secure Attention Key". Required for
2995 * super-paranoid applications --- see the Orange Book for more details.
2997 * This code could be nicer; ideally it should send a HUP, wait a few
2998 * seconds, then send a INT, and then a KILL signal. But you then
2999 * have to coordinate with the init process, since all processes associated
3000 * with the current tty must be dead before the new getty is allowed
3003 * Now, if it would be correct ;-/ The current code has a nasty hole -
3004 * it doesn't catch files in flight. We may send the descriptor to ourselves
3005 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3007 * Nasty bug: do_SAK is being called in interrupt context. This can
3008 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3010 void __do_SAK(struct tty_struct *tty)
3015 struct task_struct *g, *p;
3016 struct pid *session;
3021 session = tty->session;
3023 tty_ldisc_flush(tty);
3025 tty_driver_flush_buffer(tty);
3027 read_lock(&tasklist_lock);
3028 /* Kill the entire session */
3029 do_each_pid_task(session, PIDTYPE_SID, p) {
3030 printk(KERN_NOTICE "SAK: killed process %d"
3031 " (%s): task_session(p)==tty->session\n",
3032 task_pid_nr(p), p->comm);
3033 send_sig(SIGKILL, p, 1);
3034 } while_each_pid_task(session, PIDTYPE_SID, p);
3035 /* Now kill any processes that happen to have the
3038 do_each_thread(g, p) {
3039 if (p->signal->tty == tty) {
3040 printk(KERN_NOTICE "SAK: killed process %d"
3041 " (%s): task_session(p)==tty->session\n",
3042 task_pid_nr(p), p->comm);
3043 send_sig(SIGKILL, p, 1);
3047 i = iterate_fd(p->files, 0, this_tty, tty);
3049 printk(KERN_NOTICE "SAK: killed process %d"
3050 " (%s): fd#%d opened to the tty\n",
3051 task_pid_nr(p), p->comm, i - 1);
3052 force_sig(SIGKILL, p);
3055 } while_each_thread(g, p);
3056 read_unlock(&tasklist_lock);
3060 static void do_SAK_work(struct work_struct *work)
3062 struct tty_struct *tty =
3063 container_of(work, struct tty_struct, SAK_work);
3068 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3069 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3070 * the values which we write to it will be identical to the values which it
3071 * already has. --akpm
3073 void do_SAK(struct tty_struct *tty)
3077 schedule_work(&tty->SAK_work);
3080 EXPORT_SYMBOL(do_SAK);
3082 static int dev_match_devt(struct device *dev, const void *data)
3084 const dev_t *devt = data;
3085 return dev->devt == *devt;
3088 /* Must put_device() after it's unused! */
3089 static struct device *tty_get_device(struct tty_struct *tty)
3091 dev_t devt = tty_devnum(tty);
3092 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3099 * This subroutine allocates and initializes a tty structure.
3101 * Locking: none - tty in question is not exposed at this point
3104 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3106 struct tty_struct *tty;
3108 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3112 kref_init(&tty->kref);
3113 tty->magic = TTY_MAGIC;
3114 tty_ldisc_init(tty);
3115 tty->session = NULL;
3117 mutex_init(&tty->legacy_mutex);
3118 mutex_init(&tty->throttle_mutex);
3119 init_rwsem(&tty->termios_rwsem);
3120 mutex_init(&tty->winsize_mutex);
3121 init_ldsem(&tty->ldisc_sem);
3122 init_waitqueue_head(&tty->write_wait);
3123 init_waitqueue_head(&tty->read_wait);
3124 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3125 mutex_init(&tty->atomic_write_lock);
3126 spin_lock_init(&tty->ctrl_lock);
3127 spin_lock_init(&tty->flow_lock);
3128 INIT_LIST_HEAD(&tty->tty_files);
3129 INIT_WORK(&tty->SAK_work, do_SAK_work);
3131 tty->driver = driver;
3132 tty->ops = driver->ops;
3134 tty_line_name(driver, idx, tty->name);
3135 tty->dev = tty_get_device(tty);
3141 * deinitialize_tty_struct
3142 * @tty: tty to deinitialize
3144 * This subroutine deinitializes a tty structure that has been newly
3145 * allocated but tty_release cannot be called on that yet.
3147 * Locking: none - tty in question must not be exposed at this point
3149 void deinitialize_tty_struct(struct tty_struct *tty)
3151 tty_ldisc_deinit(tty);
3155 * tty_put_char - write one character to a tty
3159 * Write one byte to the tty using the provided put_char method
3160 * if present. Returns the number of characters successfully output.
3162 * Note: the specific put_char operation in the driver layer may go
3163 * away soon. Don't call it directly, use this method
3166 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3168 if (tty->ops->put_char)
3169 return tty->ops->put_char(tty, ch);
3170 return tty->ops->write(tty, &ch, 1);
3172 EXPORT_SYMBOL_GPL(tty_put_char);
3174 struct class *tty_class;
3176 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3177 unsigned int index, unsigned int count)
3181 /* init here, since reused cdevs cause crashes */
3182 driver->cdevs[index] = cdev_alloc();
3183 if (!driver->cdevs[index])
3185 driver->cdevs[index]->ops = &tty_fops;
3186 driver->cdevs[index]->owner = driver->owner;
3187 err = cdev_add(driver->cdevs[index], dev, count);
3189 kobject_put(&driver->cdevs[index]->kobj);
3194 * tty_register_device - register a tty device
3195 * @driver: the tty driver that describes the tty device
3196 * @index: the index in the tty driver for this tty device
3197 * @device: a struct device that is associated with this tty device.
3198 * This field is optional, if there is no known struct device
3199 * for this tty device it can be set to NULL safely.
3201 * Returns a pointer to the struct device for this tty device
3202 * (or ERR_PTR(-EFOO) on error).
3204 * This call is required to be made to register an individual tty device
3205 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3206 * that bit is not set, this function should not be called by a tty
3212 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3213 struct device *device)
3215 return tty_register_device_attr(driver, index, device, NULL, NULL);
3217 EXPORT_SYMBOL(tty_register_device);
3219 static void tty_device_create_release(struct device *dev)
3221 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3226 * tty_register_device_attr - register a tty device
3227 * @driver: the tty driver that describes the tty device
3228 * @index: the index in the tty driver for this tty device
3229 * @device: a struct device that is associated with this tty device.
3230 * This field is optional, if there is no known struct device
3231 * for this tty device it can be set to NULL safely.
3232 * @drvdata: Driver data to be set to device.
3233 * @attr_grp: Attribute group to be set on device.
3235 * Returns a pointer to the struct device for this tty device
3236 * (or ERR_PTR(-EFOO) on error).
3238 * This call is required to be made to register an individual tty device
3239 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3240 * that bit is not set, this function should not be called by a tty
3245 struct device *tty_register_device_attr(struct tty_driver *driver,
3246 unsigned index, struct device *device,
3248 const struct attribute_group **attr_grp)
3251 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3252 struct device *dev = NULL;
3253 int retval = -ENODEV;
3256 if (index >= driver->num) {
3257 printk(KERN_ERR "Attempt to register invalid tty line number "
3259 return ERR_PTR(-EINVAL);
3262 if (driver->type == TTY_DRIVER_TYPE_PTY)
3263 pty_line_name(driver, index, name);
3265 tty_line_name(driver, index, name);
3267 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3268 retval = tty_cdev_add(driver, devt, index, 1);
3274 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3281 dev->class = tty_class;
3282 dev->parent = device;
3283 dev->release = tty_device_create_release;
3284 dev_set_name(dev, "%s", name);
3285 dev->groups = attr_grp;
3286 dev_set_drvdata(dev, drvdata);
3288 retval = device_register(dev);
3297 cdev_del(driver->cdevs[index]);
3298 driver->cdevs[index] = NULL;
3300 return ERR_PTR(retval);
3302 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3305 * tty_unregister_device - unregister a tty device
3306 * @driver: the tty driver that describes the tty device
3307 * @index: the index in the tty driver for this tty device
3309 * If a tty device is registered with a call to tty_register_device() then
3310 * this function must be called when the tty device is gone.
3315 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3317 device_destroy(tty_class,
3318 MKDEV(driver->major, driver->minor_start) + index);
3319 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3320 cdev_del(driver->cdevs[index]);
3321 driver->cdevs[index] = NULL;
3324 EXPORT_SYMBOL(tty_unregister_device);
3327 * __tty_alloc_driver -- allocate tty driver
3328 * @lines: count of lines this driver can handle at most
3329 * @owner: module which is repsonsible for this driver
3330 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3332 * This should not be called directly, some of the provided macros should be
3333 * used instead. Use IS_ERR and friends on @retval.
3335 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3336 unsigned long flags)
3338 struct tty_driver *driver;
3339 unsigned int cdevs = 1;
3342 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3343 return ERR_PTR(-EINVAL);
3345 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3347 return ERR_PTR(-ENOMEM);
3349 kref_init(&driver->kref);
3350 driver->magic = TTY_DRIVER_MAGIC;
3351 driver->num = lines;
3352 driver->owner = owner;
3353 driver->flags = flags;
3355 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3356 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3358 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3360 if (!driver->ttys || !driver->termios) {
3366 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3367 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3369 if (!driver->ports) {
3376 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3377 if (!driver->cdevs) {
3384 kfree(driver->ports);
3385 kfree(driver->ttys);
3386 kfree(driver->termios);
3387 kfree(driver->cdevs);
3389 return ERR_PTR(err);
3391 EXPORT_SYMBOL(__tty_alloc_driver);
3393 static void destruct_tty_driver(struct kref *kref)
3395 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3397 struct ktermios *tp;
3399 if (driver->flags & TTY_DRIVER_INSTALLED) {
3401 * Free the termios and termios_locked structures because
3402 * we don't want to get memory leaks when modular tty
3403 * drivers are removed from the kernel.
3405 for (i = 0; i < driver->num; i++) {
3406 tp = driver->termios[i];
3408 driver->termios[i] = NULL;
3411 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3412 tty_unregister_device(driver, i);
3414 proc_tty_unregister_driver(driver);
3415 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3416 cdev_del(driver->cdevs[0]);
3418 kfree(driver->cdevs);
3419 kfree(driver->ports);
3420 kfree(driver->termios);
3421 kfree(driver->ttys);
3425 void tty_driver_kref_put(struct tty_driver *driver)
3427 kref_put(&driver->kref, destruct_tty_driver);
3429 EXPORT_SYMBOL(tty_driver_kref_put);
3431 void tty_set_operations(struct tty_driver *driver,
3432 const struct tty_operations *op)
3436 EXPORT_SYMBOL(tty_set_operations);
3438 void put_tty_driver(struct tty_driver *d)
3440 tty_driver_kref_put(d);
3442 EXPORT_SYMBOL(put_tty_driver);
3445 * Called by a tty driver to register itself.
3447 int tty_register_driver(struct tty_driver *driver)
3454 if (!driver->major) {
3455 error = alloc_chrdev_region(&dev, driver->minor_start,
3456 driver->num, driver->name);
3458 driver->major = MAJOR(dev);
3459 driver->minor_start = MINOR(dev);
3462 dev = MKDEV(driver->major, driver->minor_start);
3463 error = register_chrdev_region(dev, driver->num, driver->name);
3468 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3469 error = tty_cdev_add(driver, dev, 0, driver->num);
3471 goto err_unreg_char;
3474 mutex_lock(&tty_mutex);
3475 list_add(&driver->tty_drivers, &tty_drivers);
3476 mutex_unlock(&tty_mutex);
3478 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3479 for (i = 0; i < driver->num; i++) {
3480 d = tty_register_device(driver, i, NULL);
3483 goto err_unreg_devs;
3487 proc_tty_register_driver(driver);
3488 driver->flags |= TTY_DRIVER_INSTALLED;
3492 for (i--; i >= 0; i--)
3493 tty_unregister_device(driver, i);
3495 mutex_lock(&tty_mutex);
3496 list_del(&driver->tty_drivers);
3497 mutex_unlock(&tty_mutex);
3500 unregister_chrdev_region(dev, driver->num);
3504 EXPORT_SYMBOL(tty_register_driver);
3507 * Called by a tty driver to unregister itself.
3509 int tty_unregister_driver(struct tty_driver *driver)
3513 if (driver->refcount)
3516 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3518 mutex_lock(&tty_mutex);
3519 list_del(&driver->tty_drivers);
3520 mutex_unlock(&tty_mutex);
3524 EXPORT_SYMBOL(tty_unregister_driver);
3526 dev_t tty_devnum(struct tty_struct *tty)
3528 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3530 EXPORT_SYMBOL(tty_devnum);
3532 void tty_default_fops(struct file_operations *fops)
3538 * Initialize the console device. This is called *early*, so
3539 * we can't necessarily depend on lots of kernel help here.
3540 * Just do some early initializations, and do the complex setup
3543 void __init console_init(void)
3547 /* Setup the default TTY line discipline. */
3551 * set up the console device so that later boot sequences can
3552 * inform about problems etc..
3554 call = __con_initcall_start;
3555 while (call < __con_initcall_end) {
3561 static char *tty_devnode(struct device *dev, umode_t *mode)
3565 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3566 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3571 static int __init tty_class_init(void)
3573 tty_class = class_create(THIS_MODULE, "tty");
3574 if (IS_ERR(tty_class))
3575 return PTR_ERR(tty_class);
3576 tty_class->devnode = tty_devnode;
3580 postcore_initcall(tty_class_init);
3582 /* 3/2004 jmc: why do these devices exist? */
3583 static struct cdev tty_cdev, console_cdev;
3585 static ssize_t show_cons_active(struct device *dev,
3586 struct device_attribute *attr, char *buf)
3588 struct console *cs[16];
3594 for_each_console(c) {
3599 if ((c->flags & CON_ENABLED) == 0)
3602 if (i >= ARRAY_SIZE(cs))
3606 int index = cs[i]->index;
3607 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3609 /* don't resolve tty0 as some programs depend on it */
3610 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3611 count += tty_line_name(drv, index, buf + count);
3613 count += sprintf(buf + count, "%s%d",
3614 cs[i]->name, cs[i]->index);
3616 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3622 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3624 static struct attribute *cons_dev_attrs[] = {
3625 &dev_attr_active.attr,
3629 ATTRIBUTE_GROUPS(cons_dev);
3631 static struct device *consdev;
3633 void console_sysfs_notify(void)
3636 sysfs_notify(&consdev->kobj, NULL, "active");
3640 * Ok, now we can initialize the rest of the tty devices and can count
3641 * on memory allocations, interrupts etc..
3643 int __init tty_init(void)
3645 cdev_init(&tty_cdev, &tty_fops);
3646 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3647 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3648 panic("Couldn't register /dev/tty driver\n");
3649 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3651 cdev_init(&console_cdev, &console_fops);
3652 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3653 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3654 panic("Couldn't register /dev/console driver\n");
3655 consdev = device_create_with_groups(tty_class, NULL,
3656 MKDEV(TTYAUX_MAJOR, 1), NULL,
3657 cons_dev_groups, "console");
3658 if (IS_ERR(consdev))
3662 vty_init(&console_fops);