2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched.h>
73 #include <linux/interrupt.h>
74 #include <linux/tty.h>
75 #include <linux/tty_driver.h>
76 #include <linux/tty_flip.h>
77 #include <linux/devpts_fs.h>
78 #include <linux/file.h>
79 #include <linux/fdtable.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/device.h>
92 #include <linux/wait.h>
93 #include <linux/bitops.h>
94 #include <linux/delay.h>
95 #include <linux/seq_file.h>
96 #include <linux/serial.h>
97 #include <linux/ratelimit.h>
99 #include <linux/uaccess.h>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
106 #include <linux/nsproxy.h>
108 #undef TTY_DEBUG_HANGUP
110 #define TTY_PARANOIA_CHECK 1
111 #define CHECK_TTY_COUNT 1
113 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
114 .c_iflag = ICRNL | IXON,
115 .c_oflag = OPOST | ONLCR,
116 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
117 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
118 ECHOCTL | ECHOKE | IEXTEN,
124 EXPORT_SYMBOL(tty_std_termios);
126 /* This list gets poked at by procfs and various bits of boot up code. This
127 could do with some rationalisation such as pulling the tty proc function
130 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
132 /* Mutex to protect creating and releasing a tty. This is shared with
133 vt.c for deeply disgusting hack reasons */
134 DEFINE_MUTEX(tty_mutex);
135 EXPORT_SYMBOL(tty_mutex);
137 /* Spinlock to protect the tty->tty_files list */
138 DEFINE_SPINLOCK(tty_files_lock);
140 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
141 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
142 ssize_t redirected_tty_write(struct file *, const char __user *,
144 static unsigned int tty_poll(struct file *, poll_table *);
145 static int tty_open(struct inode *, struct file *);
146 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
148 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
151 #define tty_compat_ioctl NULL
153 static int __tty_fasync(int fd, struct file *filp, int on);
154 static int tty_fasync(int fd, struct file *filp, int on);
155 static void release_tty(struct tty_struct *tty, int idx);
156 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
157 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
160 * alloc_tty_struct - allocate a tty object
162 * Return a new empty tty structure. The data fields have not
163 * been initialized in any way but has been zeroed
168 struct tty_struct *alloc_tty_struct(void)
170 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
174 * free_tty_struct - free a disused tty
175 * @tty: tty struct to free
177 * Free the write buffers, tty queue and tty memory itself.
179 * Locking: none. Must be called after tty is definitely unused
182 void free_tty_struct(struct tty_struct *tty)
185 put_device(tty->dev);
186 kfree(tty->write_buf);
187 tty_buffer_free_all(tty);
188 tty->magic = 0xDEADDEAD;
192 static inline struct tty_struct *file_tty(struct file *file)
194 return ((struct tty_file_private *)file->private_data)->tty;
197 int tty_alloc_file(struct file *file)
199 struct tty_file_private *priv;
201 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
205 file->private_data = priv;
210 /* Associate a new file with the tty structure */
211 void tty_add_file(struct tty_struct *tty, struct file *file)
213 struct tty_file_private *priv = file->private_data;
218 spin_lock(&tty_files_lock);
219 list_add(&priv->list, &tty->tty_files);
220 spin_unlock(&tty_files_lock);
224 * tty_free_file - free file->private_data
226 * This shall be used only for fail path handling when tty_add_file was not
229 void tty_free_file(struct file *file)
231 struct tty_file_private *priv = file->private_data;
233 file->private_data = NULL;
237 /* Delete file from its tty */
238 void tty_del_file(struct file *file)
240 struct tty_file_private *priv = file->private_data;
242 spin_lock(&tty_files_lock);
243 list_del(&priv->list);
244 spin_unlock(&tty_files_lock);
249 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
252 * tty_name - return tty naming
253 * @tty: tty structure
254 * @buf: buffer for output
256 * Convert a tty structure into a name. The name reflects the kernel
257 * naming policy and if udev is in use may not reflect user space
262 char *tty_name(struct tty_struct *tty, char *buf)
264 if (!tty) /* Hmm. NULL pointer. That's fun. */
265 strcpy(buf, "NULL tty");
267 strcpy(buf, tty->name);
271 EXPORT_SYMBOL(tty_name);
273 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
276 #ifdef TTY_PARANOIA_CHECK
279 "null TTY for (%d:%d) in %s\n",
280 imajor(inode), iminor(inode), routine);
283 if (tty->magic != TTY_MAGIC) {
285 "bad magic number for tty struct (%d:%d) in %s\n",
286 imajor(inode), iminor(inode), routine);
293 static int check_tty_count(struct tty_struct *tty, const char *routine)
295 #ifdef CHECK_TTY_COUNT
299 spin_lock(&tty_files_lock);
300 list_for_each(p, &tty->tty_files) {
303 spin_unlock(&tty_files_lock);
304 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
305 tty->driver->subtype == PTY_TYPE_SLAVE &&
306 tty->link && tty->link->count)
308 if (tty->count != count) {
309 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
310 "!= #fd's(%d) in %s\n",
311 tty->name, tty->count, count, routine);
319 * get_tty_driver - find device of a tty
320 * @dev_t: device identifier
321 * @index: returns the index of the tty
323 * This routine returns a tty driver structure, given a device number
324 * and also passes back the index number.
326 * Locking: caller must hold tty_mutex
329 static struct tty_driver *get_tty_driver(dev_t device, int *index)
331 struct tty_driver *p;
333 list_for_each_entry(p, &tty_drivers, tty_drivers) {
334 dev_t base = MKDEV(p->major, p->minor_start);
335 if (device < base || device >= base + p->num)
337 *index = device - base;
338 return tty_driver_kref_get(p);
343 #ifdef CONFIG_CONSOLE_POLL
346 * tty_find_polling_driver - find device of a polled tty
347 * @name: name string to match
348 * @line: pointer to resulting tty line nr
350 * This routine returns a tty driver structure, given a name
351 * and the condition that the tty driver is capable of polled
354 struct tty_driver *tty_find_polling_driver(char *name, int *line)
356 struct tty_driver *p, *res = NULL;
361 for (str = name; *str; str++)
362 if ((*str >= '0' && *str <= '9') || *str == ',')
368 tty_line = simple_strtoul(str, &str, 10);
370 mutex_lock(&tty_mutex);
371 /* Search through the tty devices to look for a match */
372 list_for_each_entry(p, &tty_drivers, tty_drivers) {
373 if (strncmp(name, p->name, len) != 0)
381 if (tty_line >= 0 && tty_line < p->num && p->ops &&
382 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
383 res = tty_driver_kref_get(p);
388 mutex_unlock(&tty_mutex);
392 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
396 * tty_check_change - check for POSIX terminal changes
399 * If we try to write to, or set the state of, a terminal and we're
400 * not in the foreground, send a SIGTTOU. If the signal is blocked or
401 * ignored, go ahead and perform the operation. (POSIX 7.2)
406 int tty_check_change(struct tty_struct *tty)
411 if (current->signal->tty != tty)
414 spin_lock_irqsave(&tty->ctrl_lock, flags);
417 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
420 if (task_pgrp(current) == tty->pgrp)
422 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
423 if (is_ignored(SIGTTOU))
425 if (is_current_pgrp_orphaned()) {
429 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
430 set_thread_flag(TIF_SIGPENDING);
435 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
439 EXPORT_SYMBOL(tty_check_change);
441 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
442 size_t count, loff_t *ppos)
447 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
448 size_t count, loff_t *ppos)
453 /* No kernel lock held - none needed ;) */
454 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
456 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
459 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
462 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
465 static long hung_up_tty_compat_ioctl(struct file *file,
466 unsigned int cmd, unsigned long arg)
468 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
471 static const struct file_operations tty_fops = {
476 .unlocked_ioctl = tty_ioctl,
477 .compat_ioctl = tty_compat_ioctl,
479 .release = tty_release,
480 .fasync = tty_fasync,
483 static const struct file_operations console_fops = {
486 .write = redirected_tty_write,
488 .unlocked_ioctl = tty_ioctl,
489 .compat_ioctl = tty_compat_ioctl,
491 .release = tty_release,
492 .fasync = tty_fasync,
495 static const struct file_operations hung_up_tty_fops = {
497 .read = hung_up_tty_read,
498 .write = hung_up_tty_write,
499 .poll = hung_up_tty_poll,
500 .unlocked_ioctl = hung_up_tty_ioctl,
501 .compat_ioctl = hung_up_tty_compat_ioctl,
502 .release = tty_release,
505 static DEFINE_SPINLOCK(redirect_lock);
506 static struct file *redirect;
509 * tty_wakeup - request more data
512 * Internal and external helper for wakeups of tty. This function
513 * informs the line discipline if present that the driver is ready
514 * to receive more output data.
517 void tty_wakeup(struct tty_struct *tty)
519 struct tty_ldisc *ld;
521 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
522 ld = tty_ldisc_ref(tty);
524 if (ld->ops->write_wakeup)
525 ld->ops->write_wakeup(tty);
529 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
532 EXPORT_SYMBOL_GPL(tty_wakeup);
535 * __tty_hangup - actual handler for hangup events
538 * This can be called by the "eventd" kernel thread. That is process
539 * synchronous but doesn't hold any locks, so we need to make sure we
540 * have the appropriate locks for what we're doing.
542 * The hangup event clears any pending redirections onto the hung up
543 * device. It ensures future writes will error and it does the needed
544 * line discipline hangup and signal delivery. The tty object itself
549 * redirect lock for undoing redirection
550 * file list lock for manipulating list of ttys
551 * tty_ldisc_lock from called functions
552 * termios_mutex resetting termios data
553 * tasklist_lock to walk task list for hangup event
554 * ->siglock to protect ->signal/->sighand
556 void __tty_hangup(struct tty_struct *tty)
558 struct file *cons_filp = NULL;
559 struct file *filp, *f = NULL;
560 struct task_struct *p;
561 struct tty_file_private *priv;
562 int closecount = 0, n;
570 spin_lock(&redirect_lock);
571 if (redirect && file_tty(redirect) == tty) {
575 spin_unlock(&redirect_lock);
579 /* some functions below drop BTM, so we need this bit */
580 set_bit(TTY_HUPPING, &tty->flags);
582 /* inuse_filps is protected by the single tty lock,
583 this really needs to change if we want to flush the
584 workqueue with the lock held */
585 check_tty_count(tty, "tty_hangup");
587 spin_lock(&tty_files_lock);
588 /* This breaks for file handles being sent over AF_UNIX sockets ? */
589 list_for_each_entry(priv, &tty->tty_files, list) {
591 if (filp->f_op->write == redirected_tty_write)
593 if (filp->f_op->write != tty_write)
596 __tty_fasync(-1, filp, 0); /* can't block */
597 filp->f_op = &hung_up_tty_fops;
599 spin_unlock(&tty_files_lock);
602 * it drops BTM and thus races with reopen
603 * we protect the race by TTY_HUPPING
605 tty_ldisc_hangup(tty);
607 read_lock(&tasklist_lock);
609 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
610 spin_lock_irq(&p->sighand->siglock);
611 if (p->signal->tty == tty) {
612 p->signal->tty = NULL;
613 /* We defer the dereferences outside fo
617 if (!p->signal->leader) {
618 spin_unlock_irq(&p->sighand->siglock);
621 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
622 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
623 put_pid(p->signal->tty_old_pgrp); /* A noop */
624 spin_lock_irqsave(&tty->ctrl_lock, flags);
626 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
627 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
628 spin_unlock_irq(&p->sighand->siglock);
629 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
631 read_unlock(&tasklist_lock);
633 spin_lock_irqsave(&tty->ctrl_lock, flags);
634 clear_bit(TTY_THROTTLED, &tty->flags);
635 clear_bit(TTY_PUSH, &tty->flags);
636 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
637 put_pid(tty->session);
641 tty->ctrl_status = 0;
642 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
644 /* Account for the p->signal references we killed */
649 * If one of the devices matches a console pointer, we
650 * cannot just call hangup() because that will cause
651 * tty->count and state->count to go out of sync.
652 * So we just call close() the right number of times.
656 for (n = 0; n < closecount; n++)
657 tty->ops->close(tty, cons_filp);
658 } else if (tty->ops->hangup)
659 (tty->ops->hangup)(tty);
661 * We don't want to have driver/ldisc interactions beyond
662 * the ones we did here. The driver layer expects no
663 * calls after ->hangup() from the ldisc side. However we
664 * can't yet guarantee all that.
666 set_bit(TTY_HUPPED, &tty->flags);
667 clear_bit(TTY_HUPPING, &tty->flags);
668 tty_ldisc_enable(tty);
676 static void do_tty_hangup(struct work_struct *work)
678 struct tty_struct *tty =
679 container_of(work, struct tty_struct, hangup_work);
685 * tty_hangup - trigger a hangup event
686 * @tty: tty to hangup
688 * A carrier loss (virtual or otherwise) has occurred on this like
689 * schedule a hangup sequence to run after this event.
692 void tty_hangup(struct tty_struct *tty)
694 #ifdef TTY_DEBUG_HANGUP
696 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
698 schedule_work(&tty->hangup_work);
701 EXPORT_SYMBOL(tty_hangup);
704 * tty_vhangup - process vhangup
705 * @tty: tty to hangup
707 * The user has asked via system call for the terminal to be hung up.
708 * We do this synchronously so that when the syscall returns the process
709 * is complete. That guarantee is necessary for security reasons.
712 void tty_vhangup(struct tty_struct *tty)
714 #ifdef TTY_DEBUG_HANGUP
717 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
722 EXPORT_SYMBOL(tty_vhangup);
726 * tty_vhangup_self - process vhangup for own ctty
728 * Perform a vhangup on the current controlling tty
731 void tty_vhangup_self(void)
733 struct tty_struct *tty;
735 tty = get_current_tty();
743 * tty_hung_up_p - was tty hung up
744 * @filp: file pointer of tty
746 * Return true if the tty has been subject to a vhangup or a carrier
750 int tty_hung_up_p(struct file *filp)
752 return (filp->f_op == &hung_up_tty_fops);
755 EXPORT_SYMBOL(tty_hung_up_p);
757 static void session_clear_tty(struct pid *session)
759 struct task_struct *p;
760 do_each_pid_task(session, PIDTYPE_SID, p) {
762 } while_each_pid_task(session, PIDTYPE_SID, p);
766 * disassociate_ctty - disconnect controlling tty
767 * @on_exit: true if exiting so need to "hang up" the session
769 * This function is typically called only by the session leader, when
770 * it wants to disassociate itself from its controlling tty.
772 * It performs the following functions:
773 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
774 * (2) Clears the tty from being controlling the session
775 * (3) Clears the controlling tty for all processes in the
778 * The argument on_exit is set to 1 if called when a process is
779 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
782 * BTM is taken for hysterical raisins, and held when
783 * called from no_tty().
784 * tty_mutex is taken to protect tty
785 * ->siglock is taken to protect ->signal/->sighand
786 * tasklist_lock is taken to walk process list for sessions
787 * ->siglock is taken to protect ->signal/->sighand
790 void disassociate_ctty(int on_exit)
792 struct tty_struct *tty;
794 if (!current->signal->leader)
797 tty = get_current_tty();
799 struct pid *tty_pgrp = get_pid(tty->pgrp);
801 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
806 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
808 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
811 } else if (on_exit) {
812 struct pid *old_pgrp;
813 spin_lock_irq(¤t->sighand->siglock);
814 old_pgrp = current->signal->tty_old_pgrp;
815 current->signal->tty_old_pgrp = NULL;
816 spin_unlock_irq(¤t->sighand->siglock);
818 kill_pgrp(old_pgrp, SIGHUP, on_exit);
819 kill_pgrp(old_pgrp, SIGCONT, on_exit);
825 spin_lock_irq(¤t->sighand->siglock);
826 put_pid(current->signal->tty_old_pgrp);
827 current->signal->tty_old_pgrp = NULL;
828 spin_unlock_irq(¤t->sighand->siglock);
830 tty = get_current_tty();
833 spin_lock_irqsave(&tty->ctrl_lock, flags);
834 put_pid(tty->session);
838 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
841 #ifdef TTY_DEBUG_HANGUP
842 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
847 /* Now clear signal->tty under the lock */
848 read_lock(&tasklist_lock);
849 session_clear_tty(task_session(current));
850 read_unlock(&tasklist_lock);
855 * no_tty - Ensure the current process does not have a controlling tty
859 /* FIXME: Review locking here. The tty_lock never covered any race
860 between a new association and proc_clear_tty but possible we need
861 to protect against this anyway */
862 struct task_struct *tsk = current;
863 disassociate_ctty(0);
869 * stop_tty - propagate flow control
872 * Perform flow control to the driver. For PTY/TTY pairs we
873 * must also propagate the TIOCKPKT status. May be called
874 * on an already stopped device and will not re-call the driver
877 * This functionality is used by both the line disciplines for
878 * halting incoming flow and by the driver. It may therefore be
879 * called from any context, may be under the tty atomic_write_lock
883 * Uses the tty control lock internally
886 void stop_tty(struct tty_struct *tty)
889 spin_lock_irqsave(&tty->ctrl_lock, flags);
891 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
895 if (tty->link && tty->link->packet) {
896 tty->ctrl_status &= ~TIOCPKT_START;
897 tty->ctrl_status |= TIOCPKT_STOP;
898 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
900 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
902 (tty->ops->stop)(tty);
905 EXPORT_SYMBOL(stop_tty);
908 * start_tty - propagate flow control
911 * Start a tty that has been stopped if at all possible. Perform
912 * any necessary wakeups and propagate the TIOCPKT status. If this
913 * is the tty was previous stopped and is being started then the
914 * driver start method is invoked and the line discipline woken.
920 void start_tty(struct tty_struct *tty)
923 spin_lock_irqsave(&tty->ctrl_lock, flags);
924 if (!tty->stopped || tty->flow_stopped) {
925 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
929 if (tty->link && tty->link->packet) {
930 tty->ctrl_status &= ~TIOCPKT_STOP;
931 tty->ctrl_status |= TIOCPKT_START;
932 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
934 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
936 (tty->ops->start)(tty);
937 /* If we have a running line discipline it may need kicking */
941 EXPORT_SYMBOL(start_tty);
944 * tty_read - read method for tty device files
945 * @file: pointer to tty file
947 * @count: size of user buffer
950 * Perform the read system call function on this terminal device. Checks
951 * for hung up devices before calling the line discipline method.
954 * Locks the line discipline internally while needed. Multiple
955 * read calls may be outstanding in parallel.
958 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
962 struct inode *inode = file->f_path.dentry->d_inode;
963 struct tty_struct *tty = file_tty(file);
964 struct tty_ldisc *ld;
966 if (tty_paranoia_check(tty, inode, "tty_read"))
968 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
971 /* We want to wait for the line discipline to sort out in this
973 ld = tty_ldisc_ref_wait(tty);
975 i = (ld->ops->read)(tty, file, buf, count);
980 inode->i_atime = current_fs_time(inode->i_sb);
984 void tty_write_unlock(struct tty_struct *tty)
985 __releases(&tty->atomic_write_lock)
987 mutex_unlock(&tty->atomic_write_lock);
988 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
991 int tty_write_lock(struct tty_struct *tty, int ndelay)
992 __acquires(&tty->atomic_write_lock)
994 if (!mutex_trylock(&tty->atomic_write_lock)) {
997 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1004 * Split writes up in sane blocksizes to avoid
1005 * denial-of-service type attacks
1007 static inline ssize_t do_tty_write(
1008 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1009 struct tty_struct *tty,
1011 const char __user *buf,
1014 ssize_t ret, written = 0;
1017 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1022 * We chunk up writes into a temporary buffer. This
1023 * simplifies low-level drivers immensely, since they
1024 * don't have locking issues and user mode accesses.
1026 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1029 * The default chunk-size is 2kB, because the NTTY
1030 * layer has problems with bigger chunks. It will
1031 * claim to be able to handle more characters than
1034 * FIXME: This can probably go away now except that 64K chunks
1035 * are too likely to fail unless switched to vmalloc...
1038 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1043 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1044 if (tty->write_cnt < chunk) {
1045 unsigned char *buf_chunk;
1050 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1055 kfree(tty->write_buf);
1056 tty->write_cnt = chunk;
1057 tty->write_buf = buf_chunk;
1060 /* Do the write .. */
1062 size_t size = count;
1066 if (copy_from_user(tty->write_buf, buf, size))
1068 ret = write(tty, file, tty->write_buf, size);
1077 if (signal_pending(current))
1082 struct inode *inode = file->f_path.dentry->d_inode;
1083 inode->i_mtime = current_fs_time(inode->i_sb);
1087 tty_write_unlock(tty);
1092 * tty_write_message - write a message to a certain tty, not just the console.
1093 * @tty: the destination tty_struct
1094 * @msg: the message to write
1096 * This is used for messages that need to be redirected to a specific tty.
1097 * We don't put it into the syslog queue right now maybe in the future if
1100 * We must still hold the BTM and test the CLOSING flag for the moment.
1103 void tty_write_message(struct tty_struct *tty, char *msg)
1106 mutex_lock(&tty->atomic_write_lock);
1108 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1110 tty->ops->write(tty, msg, strlen(msg));
1113 tty_write_unlock(tty);
1120 * tty_write - write method for tty device file
1121 * @file: tty file pointer
1122 * @buf: user data to write
1123 * @count: bytes to write
1126 * Write data to a tty device via the line discipline.
1129 * Locks the line discipline as required
1130 * Writes to the tty driver are serialized by the atomic_write_lock
1131 * and are then processed in chunks to the device. The line discipline
1132 * write method will not be invoked in parallel for each device.
1135 static ssize_t tty_write(struct file *file, const char __user *buf,
1136 size_t count, loff_t *ppos)
1138 struct inode *inode = file->f_path.dentry->d_inode;
1139 struct tty_struct *tty = file_tty(file);
1140 struct tty_ldisc *ld;
1143 if (tty_paranoia_check(tty, inode, "tty_write"))
1145 if (!tty || !tty->ops->write ||
1146 (test_bit(TTY_IO_ERROR, &tty->flags)))
1148 /* Short term debug to catch buggy drivers */
1149 if (tty->ops->write_room == NULL)
1150 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1152 ld = tty_ldisc_ref_wait(tty);
1153 if (!ld->ops->write)
1156 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1157 tty_ldisc_deref(ld);
1161 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1162 size_t count, loff_t *ppos)
1164 struct file *p = NULL;
1166 spin_lock(&redirect_lock);
1171 spin_unlock(&redirect_lock);
1175 res = vfs_write(p, buf, count, &p->f_pos);
1179 return tty_write(file, buf, count, ppos);
1182 static char ptychar[] = "pqrstuvwxyzabcde";
1185 * pty_line_name - generate name for a pty
1186 * @driver: the tty driver in use
1187 * @index: the minor number
1188 * @p: output buffer of at least 6 bytes
1190 * Generate a name from a driver reference and write it to the output
1195 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1197 int i = index + driver->name_base;
1198 /* ->name is initialized to "ttyp", but "tty" is expected */
1199 sprintf(p, "%s%c%x",
1200 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1201 ptychar[i >> 4 & 0xf], i & 0xf);
1205 * tty_line_name - generate name for a tty
1206 * @driver: the tty driver in use
1207 * @index: the minor number
1208 * @p: output buffer of at least 7 bytes
1210 * Generate a name from a driver reference and write it to the output
1215 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1217 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1221 * tty_driver_lookup_tty() - find an existing tty, if any
1222 * @driver: the driver for the tty
1223 * @idx: the minor number
1225 * Return the tty, if found or ERR_PTR() otherwise.
1227 * Locking: tty_mutex must be held. If tty is found, the mutex must
1228 * be held until the 'fast-open' is also done. Will change once we
1229 * have refcounting in the driver and per driver locking
1231 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1232 struct inode *inode, int idx)
1234 if (driver->ops->lookup)
1235 return driver->ops->lookup(driver, inode, idx);
1237 return driver->ttys[idx];
1241 * tty_init_termios - helper for termios setup
1242 * @tty: the tty to set up
1244 * Initialise the termios structures for this tty. Thus runs under
1245 * the tty_mutex currently so we can be relaxed about ordering.
1248 int tty_init_termios(struct tty_struct *tty)
1250 struct ktermios *tp;
1251 int idx = tty->index;
1253 tp = tty->driver->termios[idx];
1255 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1258 memcpy(tp, &tty->driver->init_termios,
1259 sizeof(struct ktermios));
1260 tty->driver->termios[idx] = tp;
1263 tty->termios_locked = tp + 1;
1265 /* Compatibility until drivers always set this */
1266 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1267 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1270 EXPORT_SYMBOL_GPL(tty_init_termios);
1272 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1274 int ret = tty_init_termios(tty);
1278 tty_driver_kref_get(driver);
1280 driver->ttys[tty->index] = tty;
1283 EXPORT_SYMBOL_GPL(tty_standard_install);
1286 * tty_driver_install_tty() - install a tty entry in the driver
1287 * @driver: the driver for the tty
1290 * Install a tty object into the driver tables. The tty->index field
1291 * will be set by the time this is called. This method is responsible
1292 * for ensuring any need additional structures are allocated and
1295 * Locking: tty_mutex for now
1297 static int tty_driver_install_tty(struct tty_driver *driver,
1298 struct tty_struct *tty)
1300 return driver->ops->install ? driver->ops->install(driver, tty) :
1301 tty_standard_install(driver, tty);
1305 * tty_driver_remove_tty() - remove a tty from the driver tables
1306 * @driver: the driver for the tty
1307 * @idx: the minor number
1309 * Remvoe a tty object from the driver tables. The tty->index field
1310 * will be set by the time this is called.
1312 * Locking: tty_mutex for now
1314 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1316 if (driver->ops->remove)
1317 driver->ops->remove(driver, tty);
1319 driver->ttys[tty->index] = NULL;
1323 * tty_reopen() - fast re-open of an open tty
1324 * @tty - the tty to open
1326 * Return 0 on success, -errno on error.
1328 * Locking: tty_mutex must be held from the time the tty was found
1329 * till this open completes.
1331 static int tty_reopen(struct tty_struct *tty)
1333 struct tty_driver *driver = tty->driver;
1335 if (test_bit(TTY_CLOSING, &tty->flags) ||
1336 test_bit(TTY_HUPPING, &tty->flags) ||
1337 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1340 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1341 driver->subtype == PTY_TYPE_MASTER) {
1343 * special case for PTY masters: only one open permitted,
1344 * and the slave side open count is incremented as well.
1353 mutex_lock(&tty->ldisc_mutex);
1354 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1355 mutex_unlock(&tty->ldisc_mutex);
1361 * tty_init_dev - initialise a tty device
1362 * @driver: tty driver we are opening a device on
1363 * @idx: device index
1364 * @ret_tty: returned tty structure
1366 * Prepare a tty device. This may not be a "new" clean device but
1367 * could also be an active device. The pty drivers require special
1368 * handling because of this.
1371 * The function is called under the tty_mutex, which
1372 * protects us from the tty struct or driver itself going away.
1374 * On exit the tty device has the line discipline attached and
1375 * a reference count of 1. If a pair was created for pty/tty use
1376 * and the other was a pty master then it too has a reference count of 1.
1378 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1379 * failed open. The new code protects the open with a mutex, so it's
1380 * really quite straightforward. The mutex locking can probably be
1381 * relaxed for the (most common) case of reopening a tty.
1384 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1386 struct tty_struct *tty;
1390 * First time open is complex, especially for PTY devices.
1391 * This code guarantees that either everything succeeds and the
1392 * TTY is ready for operation, or else the table slots are vacated
1393 * and the allocated memory released. (Except that the termios
1394 * and locked termios may be retained.)
1397 if (!try_module_get(driver->owner))
1398 return ERR_PTR(-ENODEV);
1400 tty = alloc_tty_struct();
1403 goto err_module_put;
1405 initialize_tty_struct(tty, driver, idx);
1408 retval = tty_driver_install_tty(driver, tty);
1410 goto err_deinit_tty;
1413 tty->port = driver->ports[idx];
1416 * Structures all installed ... call the ldisc open routines.
1417 * If we fail here just call release_tty to clean up. No need
1418 * to decrement the use counts, as release_tty doesn't care.
1420 retval = tty_ldisc_setup(tty, tty->link);
1422 goto err_release_tty;
1423 /* Return the tty locked so that it cannot vanish under the caller */
1428 deinitialize_tty_struct(tty);
1429 free_tty_struct(tty);
1431 module_put(driver->owner);
1432 return ERR_PTR(retval);
1434 /* call the tty release_tty routine to clean out this slot */
1437 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1438 "clearing slot %d\n", idx);
1439 release_tty(tty, idx);
1440 return ERR_PTR(retval);
1443 void tty_free_termios(struct tty_struct *tty)
1445 struct ktermios *tp;
1446 int idx = tty->index;
1447 /* Kill this flag and push into drivers for locking etc */
1448 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1449 /* FIXME: Locking on ->termios array */
1451 tty->driver->termios[idx] = NULL;
1455 EXPORT_SYMBOL(tty_free_termios);
1457 void tty_shutdown(struct tty_struct *tty)
1459 tty_driver_remove_tty(tty->driver, tty);
1460 tty_free_termios(tty);
1462 EXPORT_SYMBOL(tty_shutdown);
1465 * release_one_tty - release tty structure memory
1466 * @kref: kref of tty we are obliterating
1468 * Releases memory associated with a tty structure, and clears out the
1469 * driver table slots. This function is called when a device is no longer
1470 * in use. It also gets called when setup of a device fails.
1473 * tty_mutex - sometimes only
1474 * takes the file list lock internally when working on the list
1475 * of ttys that the driver keeps.
1477 * This method gets called from a work queue so that the driver private
1478 * cleanup ops can sleep (needed for USB at least)
1480 static void release_one_tty(struct work_struct *work)
1482 struct tty_struct *tty =
1483 container_of(work, struct tty_struct, hangup_work);
1484 struct tty_driver *driver = tty->driver;
1486 if (tty->ops->cleanup)
1487 tty->ops->cleanup(tty);
1490 tty_driver_kref_put(driver);
1491 module_put(driver->owner);
1493 spin_lock(&tty_files_lock);
1494 list_del_init(&tty->tty_files);
1495 spin_unlock(&tty_files_lock);
1498 put_pid(tty->session);
1499 free_tty_struct(tty);
1502 static void queue_release_one_tty(struct kref *kref)
1504 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1506 if (tty->ops->shutdown)
1507 tty->ops->shutdown(tty);
1511 /* The hangup queue is now free so we can reuse it rather than
1512 waste a chunk of memory for each port */
1513 INIT_WORK(&tty->hangup_work, release_one_tty);
1514 schedule_work(&tty->hangup_work);
1518 * tty_kref_put - release a tty kref
1521 * Release a reference to a tty device and if need be let the kref
1522 * layer destruct the object for us
1525 void tty_kref_put(struct tty_struct *tty)
1528 kref_put(&tty->kref, queue_release_one_tty);
1530 EXPORT_SYMBOL(tty_kref_put);
1533 * release_tty - release tty structure memory
1535 * Release both @tty and a possible linked partner (think pty pair),
1536 * and decrement the refcount of the backing module.
1539 * tty_mutex - sometimes only
1540 * takes the file list lock internally when working on the list
1541 * of ttys that the driver keeps.
1542 * FIXME: should we require tty_mutex is held here ??
1545 static void release_tty(struct tty_struct *tty, int idx)
1547 /* This should always be true but check for the moment */
1548 WARN_ON(tty->index != idx);
1551 tty_kref_put(tty->link);
1556 * tty_release_checks - check a tty before real release
1557 * @tty: tty to check
1558 * @o_tty: link of @tty (if any)
1559 * @idx: index of the tty
1561 * Performs some paranoid checking before true release of the @tty.
1562 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1564 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1567 #ifdef TTY_PARANOIA_CHECK
1568 if (idx < 0 || idx >= tty->driver->num) {
1569 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1570 __func__, tty->name);
1574 /* not much to check for devpts */
1575 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1578 if (tty != tty->driver->ttys[idx]) {
1579 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1580 __func__, idx, tty->name);
1583 if (tty->termios != tty->driver->termios[idx]) {
1584 printk(KERN_DEBUG "%s: driver.termios[%d] not termios for (%s)\n",
1585 __func__, idx, tty->name);
1588 if (tty->driver->other) {
1589 if (o_tty != tty->driver->other->ttys[idx]) {
1590 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1591 __func__, idx, tty->name);
1594 if (o_tty->termios != tty->driver->other->termios[idx]) {
1595 printk(KERN_DEBUG "%s: other->termios[%d] not o_termios for (%s)\n",
1596 __func__, idx, tty->name);
1599 if (o_tty->link != tty) {
1600 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1609 * tty_release - vfs callback for close
1610 * @inode: inode of tty
1611 * @filp: file pointer for handle to tty
1613 * Called the last time each file handle is closed that references
1614 * this tty. There may however be several such references.
1617 * Takes bkl. See tty_release_dev
1619 * Even releasing the tty structures is a tricky business.. We have
1620 * to be very careful that the structures are all released at the
1621 * same time, as interrupts might otherwise get the wrong pointers.
1623 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1624 * lead to double frees or releasing memory still in use.
1627 int tty_release(struct inode *inode, struct file *filp)
1629 struct tty_struct *tty = file_tty(filp);
1630 struct tty_struct *o_tty;
1631 int pty_master, tty_closing, o_tty_closing, do_sleep;
1636 if (tty_paranoia_check(tty, inode, __func__))
1640 check_tty_count(tty, __func__);
1642 __tty_fasync(-1, filp, 0);
1645 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1646 tty->driver->subtype == PTY_TYPE_MASTER);
1647 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1648 /* Review: parallel close */
1651 if (tty_release_checks(tty, o_tty, idx)) {
1656 #ifdef TTY_DEBUG_HANGUP
1657 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1658 tty_name(tty, buf), tty->count);
1661 if (tty->ops->close)
1662 tty->ops->close(tty, filp);
1666 * Sanity check: if tty->count is going to zero, there shouldn't be
1667 * any waiters on tty->read_wait or tty->write_wait. We test the
1668 * wait queues and kick everyone out _before_ actually starting to
1669 * close. This ensures that we won't block while releasing the tty
1672 * The test for the o_tty closing is necessary, since the master and
1673 * slave sides may close in any order. If the slave side closes out
1674 * first, its count will be one, since the master side holds an open.
1675 * Thus this test wouldn't be triggered at the time the slave closes,
1678 * Note that it's possible for the tty to be opened again while we're
1679 * flushing out waiters. By recalculating the closing flags before
1680 * each iteration we avoid any problems.
1683 /* Guard against races with tty->count changes elsewhere and
1684 opens on /dev/tty */
1686 mutex_lock(&tty_mutex);
1687 tty_lock_pair(tty, o_tty);
1688 tty_closing = tty->count <= 1;
1689 o_tty_closing = o_tty &&
1690 (o_tty->count <= (pty_master ? 1 : 0));
1694 if (waitqueue_active(&tty->read_wait)) {
1695 wake_up_poll(&tty->read_wait, POLLIN);
1698 if (waitqueue_active(&tty->write_wait)) {
1699 wake_up_poll(&tty->write_wait, POLLOUT);
1703 if (o_tty_closing) {
1704 if (waitqueue_active(&o_tty->read_wait)) {
1705 wake_up_poll(&o_tty->read_wait, POLLIN);
1708 if (waitqueue_active(&o_tty->write_wait)) {
1709 wake_up_poll(&o_tty->write_wait, POLLOUT);
1716 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1717 __func__, tty_name(tty, buf));
1718 tty_unlock_pair(tty, o_tty);
1719 mutex_unlock(&tty_mutex);
1724 * The closing flags are now consistent with the open counts on
1725 * both sides, and we've completed the last operation that could
1726 * block, so it's safe to proceed with closing.
1729 if (--o_tty->count < 0) {
1730 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1731 __func__, o_tty->count, tty_name(o_tty, buf));
1735 if (--tty->count < 0) {
1736 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1737 __func__, tty->count, tty_name(tty, buf));
1742 * We've decremented tty->count, so we need to remove this file
1743 * descriptor off the tty->tty_files list; this serves two
1745 * - check_tty_count sees the correct number of file descriptors
1746 * associated with this tty.
1747 * - do_tty_hangup no longer sees this file descriptor as
1748 * something that needs to be handled for hangups.
1753 * Perform some housekeeping before deciding whether to return.
1755 * Set the TTY_CLOSING flag if this was the last open. In the
1756 * case of a pty we may have to wait around for the other side
1757 * to close, and TTY_CLOSING makes sure we can't be reopened.
1760 set_bit(TTY_CLOSING, &tty->flags);
1762 set_bit(TTY_CLOSING, &o_tty->flags);
1765 * If _either_ side is closing, make sure there aren't any
1766 * processes that still think tty or o_tty is their controlling
1769 if (tty_closing || o_tty_closing) {
1770 read_lock(&tasklist_lock);
1771 session_clear_tty(tty->session);
1773 session_clear_tty(o_tty->session);
1774 read_unlock(&tasklist_lock);
1777 mutex_unlock(&tty_mutex);
1779 /* check whether both sides are closing ... */
1780 if (!tty_closing || (o_tty && !o_tty_closing)) {
1781 tty_unlock_pair(tty, o_tty);
1785 #ifdef TTY_DEBUG_HANGUP
1786 printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__);
1789 * Ask the line discipline code to release its structures
1791 tty_ldisc_release(tty, o_tty);
1793 * The release_tty function takes care of the details of clearing
1794 * the slots and preserving the termios structure. The tty_unlock_pair
1795 * should be safe as we keep a kref while the tty is locked (so the
1796 * unlock never unlocks a freed tty).
1798 release_tty(tty, idx);
1799 tty_unlock_pair(tty, o_tty);
1801 /* Make this pty number available for reallocation */
1803 devpts_kill_index(inode, idx);
1808 * tty_open_current_tty - get tty of current task for open
1809 * @device: device number
1810 * @filp: file pointer to tty
1811 * @return: tty of the current task iff @device is /dev/tty
1813 * We cannot return driver and index like for the other nodes because
1814 * devpts will not work then. It expects inodes to be from devpts FS.
1816 * We need to move to returning a refcounted object from all the lookup
1817 * paths including this one.
1819 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1821 struct tty_struct *tty;
1823 if (device != MKDEV(TTYAUX_MAJOR, 0))
1826 tty = get_current_tty();
1828 return ERR_PTR(-ENXIO);
1830 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1833 /* FIXME: we put a reference and return a TTY! */
1834 /* This is only safe because the caller holds tty_mutex */
1839 * tty_lookup_driver - lookup a tty driver for a given device file
1840 * @device: device number
1841 * @filp: file pointer to tty
1842 * @noctty: set if the device should not become a controlling tty
1843 * @index: index for the device in the @return driver
1844 * @return: driver for this inode (with increased refcount)
1846 * If @return is not erroneous, the caller is responsible to decrement the
1847 * refcount by tty_driver_kref_put.
1849 * Locking: tty_mutex protects get_tty_driver
1851 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1852 int *noctty, int *index)
1854 struct tty_driver *driver;
1858 case MKDEV(TTY_MAJOR, 0): {
1859 extern struct tty_driver *console_driver;
1860 driver = tty_driver_kref_get(console_driver);
1861 *index = fg_console;
1866 case MKDEV(TTYAUX_MAJOR, 1): {
1867 struct tty_driver *console_driver = console_device(index);
1868 if (console_driver) {
1869 driver = tty_driver_kref_get(console_driver);
1871 /* Don't let /dev/console block */
1872 filp->f_flags |= O_NONBLOCK;
1877 return ERR_PTR(-ENODEV);
1880 driver = get_tty_driver(device, index);
1882 return ERR_PTR(-ENODEV);
1889 * tty_open - open a tty device
1890 * @inode: inode of device file
1891 * @filp: file pointer to tty
1893 * tty_open and tty_release keep up the tty count that contains the
1894 * number of opens done on a tty. We cannot use the inode-count, as
1895 * different inodes might point to the same tty.
1897 * Open-counting is needed for pty masters, as well as for keeping
1898 * track of serial lines: DTR is dropped when the last close happens.
1899 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1901 * The termios state of a pty is reset on first open so that
1902 * settings don't persist across reuse.
1904 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1905 * tty->count should protect the rest.
1906 * ->siglock protects ->signal/->sighand
1908 * Note: the tty_unlock/lock cases without a ref are only safe due to
1912 static int tty_open(struct inode *inode, struct file *filp)
1914 struct tty_struct *tty;
1916 struct tty_driver *driver = NULL;
1918 dev_t device = inode->i_rdev;
1919 unsigned saved_flags = filp->f_flags;
1921 nonseekable_open(inode, filp);
1924 retval = tty_alloc_file(filp);
1928 noctty = filp->f_flags & O_NOCTTY;
1932 mutex_lock(&tty_mutex);
1933 /* This is protected by the tty_mutex */
1934 tty = tty_open_current_tty(device, filp);
1936 retval = PTR_ERR(tty);
1939 driver = tty_lookup_driver(device, filp, &noctty, &index);
1940 if (IS_ERR(driver)) {
1941 retval = PTR_ERR(driver);
1945 /* check whether we're reopening an existing tty */
1946 tty = tty_driver_lookup_tty(driver, inode, index);
1948 retval = PTR_ERR(tty);
1955 retval = tty_reopen(tty);
1958 tty = ERR_PTR(retval);
1960 } else /* Returns with the tty_lock held for now */
1961 tty = tty_init_dev(driver, index);
1963 mutex_unlock(&tty_mutex);
1965 tty_driver_kref_put(driver);
1967 retval = PTR_ERR(tty);
1971 tty_add_file(tty, filp);
1973 check_tty_count(tty, __func__);
1974 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1975 tty->driver->subtype == PTY_TYPE_MASTER)
1977 #ifdef TTY_DEBUG_HANGUP
1978 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
1981 retval = tty->ops->open(tty, filp);
1984 filp->f_flags = saved_flags;
1986 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1987 !capable(CAP_SYS_ADMIN))
1991 #ifdef TTY_DEBUG_HANGUP
1992 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
1995 tty_unlock(tty); /* need to call tty_release without BTM */
1996 tty_release(inode, filp);
1997 if (retval != -ERESTARTSYS)
2000 if (signal_pending(current))
2005 * Need to reset f_op in case a hangup happened.
2007 if (filp->f_op == &hung_up_tty_fops)
2008 filp->f_op = &tty_fops;
2014 mutex_lock(&tty_mutex);
2016 spin_lock_irq(¤t->sighand->siglock);
2018 current->signal->leader &&
2019 !current->signal->tty &&
2020 tty->session == NULL)
2021 __proc_set_tty(current, tty);
2022 spin_unlock_irq(¤t->sighand->siglock);
2024 mutex_unlock(&tty_mutex);
2027 mutex_unlock(&tty_mutex);
2028 /* after locks to avoid deadlock */
2029 if (!IS_ERR_OR_NULL(driver))
2030 tty_driver_kref_put(driver);
2032 tty_free_file(filp);
2039 * tty_poll - check tty status
2040 * @filp: file being polled
2041 * @wait: poll wait structures to update
2043 * Call the line discipline polling method to obtain the poll
2044 * status of the device.
2046 * Locking: locks called line discipline but ldisc poll method
2047 * may be re-entered freely by other callers.
2050 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2052 struct tty_struct *tty = file_tty(filp);
2053 struct tty_ldisc *ld;
2056 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
2059 ld = tty_ldisc_ref_wait(tty);
2061 ret = (ld->ops->poll)(tty, filp, wait);
2062 tty_ldisc_deref(ld);
2066 static int __tty_fasync(int fd, struct file *filp, int on)
2068 struct tty_struct *tty = file_tty(filp);
2069 unsigned long flags;
2072 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
2075 retval = fasync_helper(fd, filp, on, &tty->fasync);
2082 if (!waitqueue_active(&tty->read_wait))
2083 tty->minimum_to_wake = 1;
2084 spin_lock_irqsave(&tty->ctrl_lock, flags);
2087 type = PIDTYPE_PGID;
2089 pid = task_pid(current);
2093 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2094 retval = __f_setown(filp, pid, type, 0);
2099 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2100 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2107 static int tty_fasync(int fd, struct file *filp, int on)
2109 struct tty_struct *tty = file_tty(filp);
2113 retval = __tty_fasync(fd, filp, on);
2120 * tiocsti - fake input character
2121 * @tty: tty to fake input into
2122 * @p: pointer to character
2124 * Fake input to a tty device. Does the necessary locking and
2127 * FIXME: does not honour flow control ??
2130 * Called functions take tty_ldisc_lock
2131 * current->signal->tty check is safe without locks
2133 * FIXME: may race normal receive processing
2136 static int tiocsti(struct tty_struct *tty, char __user *p)
2139 struct tty_ldisc *ld;
2141 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2143 if (get_user(ch, p))
2145 tty_audit_tiocsti(tty, ch);
2146 ld = tty_ldisc_ref_wait(tty);
2147 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2148 tty_ldisc_deref(ld);
2153 * tiocgwinsz - implement window query ioctl
2155 * @arg: user buffer for result
2157 * Copies the kernel idea of the window size into the user buffer.
2159 * Locking: tty->termios_mutex is taken to ensure the winsize data
2163 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2167 mutex_lock(&tty->termios_mutex);
2168 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2169 mutex_unlock(&tty->termios_mutex);
2171 return err ? -EFAULT: 0;
2175 * tty_do_resize - resize event
2176 * @tty: tty being resized
2177 * @rows: rows (character)
2178 * @cols: cols (character)
2180 * Update the termios variables and send the necessary signals to
2181 * peform a terminal resize correctly
2184 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2187 unsigned long flags;
2190 mutex_lock(&tty->termios_mutex);
2191 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2193 /* Get the PID values and reference them so we can
2194 avoid holding the tty ctrl lock while sending signals */
2195 spin_lock_irqsave(&tty->ctrl_lock, flags);
2196 pgrp = get_pid(tty->pgrp);
2197 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2200 kill_pgrp(pgrp, SIGWINCH, 1);
2205 mutex_unlock(&tty->termios_mutex);
2210 * tiocswinsz - implement window size set ioctl
2211 * @tty; tty side of tty
2212 * @arg: user buffer for result
2214 * Copies the user idea of the window size to the kernel. Traditionally
2215 * this is just advisory information but for the Linux console it
2216 * actually has driver level meaning and triggers a VC resize.
2219 * Driver dependent. The default do_resize method takes the
2220 * tty termios mutex and ctrl_lock. The console takes its own lock
2221 * then calls into the default method.
2224 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2226 struct winsize tmp_ws;
2227 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2230 if (tty->ops->resize)
2231 return tty->ops->resize(tty, &tmp_ws);
2233 return tty_do_resize(tty, &tmp_ws);
2237 * tioccons - allow admin to move logical console
2238 * @file: the file to become console
2240 * Allow the administrator to move the redirected console device
2242 * Locking: uses redirect_lock to guard the redirect information
2245 static int tioccons(struct file *file)
2247 if (!capable(CAP_SYS_ADMIN))
2249 if (file->f_op->write == redirected_tty_write) {
2251 spin_lock(&redirect_lock);
2254 spin_unlock(&redirect_lock);
2259 spin_lock(&redirect_lock);
2261 spin_unlock(&redirect_lock);
2266 spin_unlock(&redirect_lock);
2271 * fionbio - non blocking ioctl
2272 * @file: file to set blocking value
2273 * @p: user parameter
2275 * Historical tty interfaces had a blocking control ioctl before
2276 * the generic functionality existed. This piece of history is preserved
2277 * in the expected tty API of posix OS's.
2279 * Locking: none, the open file handle ensures it won't go away.
2282 static int fionbio(struct file *file, int __user *p)
2286 if (get_user(nonblock, p))
2289 spin_lock(&file->f_lock);
2291 file->f_flags |= O_NONBLOCK;
2293 file->f_flags &= ~O_NONBLOCK;
2294 spin_unlock(&file->f_lock);
2299 * tiocsctty - set controlling tty
2300 * @tty: tty structure
2301 * @arg: user argument
2303 * This ioctl is used to manage job control. It permits a session
2304 * leader to set this tty as the controlling tty for the session.
2307 * Takes tty_mutex() to protect tty instance
2308 * Takes tasklist_lock internally to walk sessions
2309 * Takes ->siglock() when updating signal->tty
2312 static int tiocsctty(struct tty_struct *tty, int arg)
2315 if (current->signal->leader && (task_session(current) == tty->session))
2318 mutex_lock(&tty_mutex);
2320 * The process must be a session leader and
2321 * not have a controlling tty already.
2323 if (!current->signal->leader || current->signal->tty) {
2330 * This tty is already the controlling
2331 * tty for another session group!
2333 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2337 read_lock(&tasklist_lock);
2338 session_clear_tty(tty->session);
2339 read_unlock(&tasklist_lock);
2345 proc_set_tty(current, tty);
2347 mutex_unlock(&tty_mutex);
2352 * tty_get_pgrp - return a ref counted pgrp pid
2355 * Returns a refcounted instance of the pid struct for the process
2356 * group controlling the tty.
2359 struct pid *tty_get_pgrp(struct tty_struct *tty)
2361 unsigned long flags;
2364 spin_lock_irqsave(&tty->ctrl_lock, flags);
2365 pgrp = get_pid(tty->pgrp);
2366 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2370 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2373 * tiocgpgrp - get process group
2374 * @tty: tty passed by user
2375 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2378 * Obtain the process group of the tty. If there is no process group
2381 * Locking: none. Reference to current->signal->tty is safe.
2384 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2389 * (tty == real_tty) is a cheap way of
2390 * testing if the tty is NOT a master pty.
2392 if (tty == real_tty && current->signal->tty != real_tty)
2394 pid = tty_get_pgrp(real_tty);
2395 ret = put_user(pid_vnr(pid), p);
2401 * tiocspgrp - attempt to set process group
2402 * @tty: tty passed by user
2403 * @real_tty: tty side device matching tty passed by user
2406 * Set the process group of the tty to the session passed. Only
2407 * permitted where the tty session is our session.
2409 * Locking: RCU, ctrl lock
2412 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2416 int retval = tty_check_change(real_tty);
2417 unsigned long flags;
2423 if (!current->signal->tty ||
2424 (current->signal->tty != real_tty) ||
2425 (real_tty->session != task_session(current)))
2427 if (get_user(pgrp_nr, p))
2432 pgrp = find_vpid(pgrp_nr);
2437 if (session_of_pgrp(pgrp) != task_session(current))
2440 spin_lock_irqsave(&tty->ctrl_lock, flags);
2441 put_pid(real_tty->pgrp);
2442 real_tty->pgrp = get_pid(pgrp);
2443 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2450 * tiocgsid - get session id
2451 * @tty: tty passed by user
2452 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2453 * @p: pointer to returned session id
2455 * Obtain the session id of the tty. If there is no session
2458 * Locking: none. Reference to current->signal->tty is safe.
2461 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2464 * (tty == real_tty) is a cheap way of
2465 * testing if the tty is NOT a master pty.
2467 if (tty == real_tty && current->signal->tty != real_tty)
2469 if (!real_tty->session)
2471 return put_user(pid_vnr(real_tty->session), p);
2475 * tiocsetd - set line discipline
2477 * @p: pointer to user data
2479 * Set the line discipline according to user request.
2481 * Locking: see tty_set_ldisc, this function is just a helper
2484 static int tiocsetd(struct tty_struct *tty, int __user *p)
2489 if (get_user(ldisc, p))
2492 ret = tty_set_ldisc(tty, ldisc);
2498 * send_break - performed time break
2499 * @tty: device to break on
2500 * @duration: timeout in mS
2502 * Perform a timed break on hardware that lacks its own driver level
2503 * timed break functionality.
2506 * atomic_write_lock serializes
2510 static int send_break(struct tty_struct *tty, unsigned int duration)
2514 if (tty->ops->break_ctl == NULL)
2517 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2518 retval = tty->ops->break_ctl(tty, duration);
2520 /* Do the work ourselves */
2521 if (tty_write_lock(tty, 0) < 0)
2523 retval = tty->ops->break_ctl(tty, -1);
2526 if (!signal_pending(current))
2527 msleep_interruptible(duration);
2528 retval = tty->ops->break_ctl(tty, 0);
2530 tty_write_unlock(tty);
2531 if (signal_pending(current))
2538 * tty_tiocmget - get modem status
2540 * @file: user file pointer
2541 * @p: pointer to result
2543 * Obtain the modem status bits from the tty driver if the feature
2544 * is supported. Return -EINVAL if it is not available.
2546 * Locking: none (up to the driver)
2549 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2551 int retval = -EINVAL;
2553 if (tty->ops->tiocmget) {
2554 retval = tty->ops->tiocmget(tty);
2557 retval = put_user(retval, p);
2563 * tty_tiocmset - set modem status
2565 * @cmd: command - clear bits, set bits or set all
2566 * @p: pointer to desired bits
2568 * Set the modem status bits from the tty driver if the feature
2569 * is supported. Return -EINVAL if it is not available.
2571 * Locking: none (up to the driver)
2574 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2578 unsigned int set, clear, val;
2580 if (tty->ops->tiocmset == NULL)
2583 retval = get_user(val, p);
2599 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2600 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2601 return tty->ops->tiocmset(tty, set, clear);
2604 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2606 int retval = -EINVAL;
2607 struct serial_icounter_struct icount;
2608 memset(&icount, 0, sizeof(icount));
2609 if (tty->ops->get_icount)
2610 retval = tty->ops->get_icount(tty, &icount);
2613 if (copy_to_user(arg, &icount, sizeof(icount)))
2618 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2620 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2621 tty->driver->subtype == PTY_TYPE_MASTER)
2625 EXPORT_SYMBOL(tty_pair_get_tty);
2627 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2629 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2630 tty->driver->subtype == PTY_TYPE_MASTER)
2634 EXPORT_SYMBOL(tty_pair_get_pty);
2637 * Split this up, as gcc can choke on it otherwise..
2639 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2641 struct tty_struct *tty = file_tty(file);
2642 struct tty_struct *real_tty;
2643 void __user *p = (void __user *)arg;
2645 struct tty_ldisc *ld;
2646 struct inode *inode = file->f_dentry->d_inode;
2648 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2651 real_tty = tty_pair_get_tty(tty);
2654 * Factor out some common prep work
2662 retval = tty_check_change(tty);
2665 if (cmd != TIOCCBRK) {
2666 tty_wait_until_sent(tty, 0);
2667 if (signal_pending(current))
2678 return tiocsti(tty, p);
2680 return tiocgwinsz(real_tty, p);
2682 return tiocswinsz(real_tty, p);
2684 return real_tty != tty ? -EINVAL : tioccons(file);
2686 return fionbio(file, p);
2688 set_bit(TTY_EXCLUSIVE, &tty->flags);
2691 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2694 if (current->signal->tty != tty)
2699 return tiocsctty(tty, arg);
2701 return tiocgpgrp(tty, real_tty, p);
2703 return tiocspgrp(tty, real_tty, p);
2705 return tiocgsid(tty, real_tty, p);
2707 return put_user(tty->ldisc->ops->num, (int __user *)p);
2709 return tiocsetd(tty, p);
2711 if (!capable(CAP_SYS_ADMIN))
2717 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2718 return put_user(ret, (unsigned int __user *)p);
2723 case TIOCSBRK: /* Turn break on, unconditionally */
2724 if (tty->ops->break_ctl)
2725 return tty->ops->break_ctl(tty, -1);
2727 case TIOCCBRK: /* Turn break off, unconditionally */
2728 if (tty->ops->break_ctl)
2729 return tty->ops->break_ctl(tty, 0);
2731 case TCSBRK: /* SVID version: non-zero arg --> no break */
2732 /* non-zero arg means wait for all output data
2733 * to be sent (performed above) but don't send break.
2734 * This is used by the tcdrain() termios function.
2737 return send_break(tty, 250);
2739 case TCSBRKP: /* support for POSIX tcsendbreak() */
2740 return send_break(tty, arg ? arg*100 : 250);
2743 return tty_tiocmget(tty, p);
2747 return tty_tiocmset(tty, cmd, p);
2749 retval = tty_tiocgicount(tty, p);
2750 /* For the moment allow fall through to the old method */
2751 if (retval != -EINVAL)
2758 /* flush tty buffer and allow ldisc to process ioctl */
2759 tty_buffer_flush(tty);
2764 if (tty->ops->ioctl) {
2765 retval = (tty->ops->ioctl)(tty, cmd, arg);
2766 if (retval != -ENOIOCTLCMD)
2769 ld = tty_ldisc_ref_wait(tty);
2771 if (ld->ops->ioctl) {
2772 retval = ld->ops->ioctl(tty, file, cmd, arg);
2773 if (retval == -ENOIOCTLCMD)
2776 tty_ldisc_deref(ld);
2780 #ifdef CONFIG_COMPAT
2781 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2784 struct inode *inode = file->f_dentry->d_inode;
2785 struct tty_struct *tty = file_tty(file);
2786 struct tty_ldisc *ld;
2787 int retval = -ENOIOCTLCMD;
2789 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2792 if (tty->ops->compat_ioctl) {
2793 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2794 if (retval != -ENOIOCTLCMD)
2798 ld = tty_ldisc_ref_wait(tty);
2799 if (ld->ops->compat_ioctl)
2800 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2802 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2803 tty_ldisc_deref(ld);
2810 * This implements the "Secure Attention Key" --- the idea is to
2811 * prevent trojan horses by killing all processes associated with this
2812 * tty when the user hits the "Secure Attention Key". Required for
2813 * super-paranoid applications --- see the Orange Book for more details.
2815 * This code could be nicer; ideally it should send a HUP, wait a few
2816 * seconds, then send a INT, and then a KILL signal. But you then
2817 * have to coordinate with the init process, since all processes associated
2818 * with the current tty must be dead before the new getty is allowed
2821 * Now, if it would be correct ;-/ The current code has a nasty hole -
2822 * it doesn't catch files in flight. We may send the descriptor to ourselves
2823 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2825 * Nasty bug: do_SAK is being called in interrupt context. This can
2826 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2828 void __do_SAK(struct tty_struct *tty)
2833 struct task_struct *g, *p;
2834 struct pid *session;
2837 struct fdtable *fdt;
2841 session = tty->session;
2843 tty_ldisc_flush(tty);
2845 tty_driver_flush_buffer(tty);
2847 read_lock(&tasklist_lock);
2848 /* Kill the entire session */
2849 do_each_pid_task(session, PIDTYPE_SID, p) {
2850 printk(KERN_NOTICE "SAK: killed process %d"
2851 " (%s): task_session(p)==tty->session\n",
2852 task_pid_nr(p), p->comm);
2853 send_sig(SIGKILL, p, 1);
2854 } while_each_pid_task(session, PIDTYPE_SID, p);
2855 /* Now kill any processes that happen to have the
2858 do_each_thread(g, p) {
2859 if (p->signal->tty == tty) {
2860 printk(KERN_NOTICE "SAK: killed process %d"
2861 " (%s): task_session(p)==tty->session\n",
2862 task_pid_nr(p), p->comm);
2863 send_sig(SIGKILL, p, 1);
2869 * We don't take a ref to the file, so we must
2870 * hold ->file_lock instead.
2872 spin_lock(&p->files->file_lock);
2873 fdt = files_fdtable(p->files);
2874 for (i = 0; i < fdt->max_fds; i++) {
2875 filp = fcheck_files(p->files, i);
2878 if (filp->f_op->read == tty_read &&
2879 file_tty(filp) == tty) {
2880 printk(KERN_NOTICE "SAK: killed process %d"
2881 " (%s): fd#%d opened to the tty\n",
2882 task_pid_nr(p), p->comm, i);
2883 force_sig(SIGKILL, p);
2887 spin_unlock(&p->files->file_lock);
2890 } while_each_thread(g, p);
2891 read_unlock(&tasklist_lock);
2895 static void do_SAK_work(struct work_struct *work)
2897 struct tty_struct *tty =
2898 container_of(work, struct tty_struct, SAK_work);
2903 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2904 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2905 * the values which we write to it will be identical to the values which it
2906 * already has. --akpm
2908 void do_SAK(struct tty_struct *tty)
2912 schedule_work(&tty->SAK_work);
2915 EXPORT_SYMBOL(do_SAK);
2917 static int dev_match_devt(struct device *dev, void *data)
2920 return dev->devt == *devt;
2923 /* Must put_device() after it's unused! */
2924 static struct device *tty_get_device(struct tty_struct *tty)
2926 dev_t devt = tty_devnum(tty);
2927 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2932 * initialize_tty_struct
2933 * @tty: tty to initialize
2935 * This subroutine initializes a tty structure that has been newly
2938 * Locking: none - tty in question must not be exposed at this point
2941 void initialize_tty_struct(struct tty_struct *tty,
2942 struct tty_driver *driver, int idx)
2944 memset(tty, 0, sizeof(struct tty_struct));
2945 kref_init(&tty->kref);
2946 tty->magic = TTY_MAGIC;
2947 tty_ldisc_init(tty);
2948 tty->session = NULL;
2950 tty->overrun_time = jiffies;
2951 tty_buffer_init(tty);
2952 mutex_init(&tty->legacy_mutex);
2953 mutex_init(&tty->termios_mutex);
2954 mutex_init(&tty->ldisc_mutex);
2955 init_waitqueue_head(&tty->write_wait);
2956 init_waitqueue_head(&tty->read_wait);
2957 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2958 mutex_init(&tty->atomic_read_lock);
2959 mutex_init(&tty->atomic_write_lock);
2960 mutex_init(&tty->output_lock);
2961 mutex_init(&tty->echo_lock);
2962 spin_lock_init(&tty->read_lock);
2963 spin_lock_init(&tty->ctrl_lock);
2964 INIT_LIST_HEAD(&tty->tty_files);
2965 INIT_WORK(&tty->SAK_work, do_SAK_work);
2967 tty->driver = driver;
2968 tty->ops = driver->ops;
2970 tty_line_name(driver, idx, tty->name);
2971 tty->dev = tty_get_device(tty);
2975 * deinitialize_tty_struct
2976 * @tty: tty to deinitialize
2978 * This subroutine deinitializes a tty structure that has been newly
2979 * allocated but tty_release cannot be called on that yet.
2981 * Locking: none - tty in question must not be exposed at this point
2983 void deinitialize_tty_struct(struct tty_struct *tty)
2985 tty_ldisc_deinit(tty);
2989 * tty_put_char - write one character to a tty
2993 * Write one byte to the tty using the provided put_char method
2994 * if present. Returns the number of characters successfully output.
2996 * Note: the specific put_char operation in the driver layer may go
2997 * away soon. Don't call it directly, use this method
3000 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3002 if (tty->ops->put_char)
3003 return tty->ops->put_char(tty, ch);
3004 return tty->ops->write(tty, &ch, 1);
3006 EXPORT_SYMBOL_GPL(tty_put_char);
3008 struct class *tty_class;
3011 * tty_register_device - register a tty device
3012 * @driver: the tty driver that describes the tty device
3013 * @index: the index in the tty driver for this tty device
3014 * @device: a struct device that is associated with this tty device.
3015 * This field is optional, if there is no known struct device
3016 * for this tty device it can be set to NULL safely.
3018 * Returns a pointer to the struct device for this tty device
3019 * (or ERR_PTR(-EFOO) on error).
3021 * This call is required to be made to register an individual tty device
3022 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3023 * that bit is not set, this function should not be called by a tty
3029 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3030 struct device *device)
3033 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
3035 if (index >= driver->num) {
3036 printk(KERN_ERR "Attempt to register invalid tty line number "
3038 return ERR_PTR(-EINVAL);
3041 if (driver->type == TTY_DRIVER_TYPE_PTY)
3042 pty_line_name(driver, index, name);
3044 tty_line_name(driver, index, name);
3046 return device_create(tty_class, device, dev, NULL, name);
3048 EXPORT_SYMBOL(tty_register_device);
3051 * tty_unregister_device - unregister a tty device
3052 * @driver: the tty driver that describes the tty device
3053 * @index: the index in the tty driver for this tty device
3055 * If a tty device is registered with a call to tty_register_device() then
3056 * this function must be called when the tty device is gone.
3061 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3063 device_destroy(tty_class,
3064 MKDEV(driver->major, driver->minor_start) + index);
3066 EXPORT_SYMBOL(tty_unregister_device);
3068 struct tty_driver *__alloc_tty_driver(int lines, struct module *owner)
3070 struct tty_driver *driver;
3072 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3074 kref_init(&driver->kref);
3075 driver->magic = TTY_DRIVER_MAGIC;
3076 driver->num = lines;
3077 driver->owner = owner;
3078 /* later we'll move allocation of tables here */
3082 EXPORT_SYMBOL(__alloc_tty_driver);
3084 static void destruct_tty_driver(struct kref *kref)
3086 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3088 struct ktermios *tp;
3091 if (driver->flags & TTY_DRIVER_INSTALLED) {
3093 * Free the termios and termios_locked structures because
3094 * we don't want to get memory leaks when modular tty
3095 * drivers are removed from the kernel.
3097 for (i = 0; i < driver->num; i++) {
3098 tp = driver->termios[i];
3100 driver->termios[i] = NULL;
3103 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3104 tty_unregister_device(driver, i);
3107 proc_tty_unregister_driver(driver);
3108 driver->ttys = NULL;
3109 driver->termios = NULL;
3111 cdev_del(&driver->cdev);
3113 kfree(driver->ports);
3117 void tty_driver_kref_put(struct tty_driver *driver)
3119 kref_put(&driver->kref, destruct_tty_driver);
3121 EXPORT_SYMBOL(tty_driver_kref_put);
3123 void tty_set_operations(struct tty_driver *driver,
3124 const struct tty_operations *op)
3128 EXPORT_SYMBOL(tty_set_operations);
3130 void put_tty_driver(struct tty_driver *d)
3132 tty_driver_kref_put(d);
3134 EXPORT_SYMBOL(put_tty_driver);
3137 * Called by a tty driver to register itself.
3139 int tty_register_driver(struct tty_driver *driver)
3147 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3148 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3153 * There is too many lines in PTY and we won't need the array there
3154 * since it has an ->install hook where it assigns ports properly.
3156 if (driver->type != TTY_DRIVER_TYPE_PTY) {
3157 driver->ports = kcalloc(driver->num, sizeof(struct tty_port *),
3159 if (!driver->ports) {
3165 if (!driver->major) {
3166 error = alloc_chrdev_region(&dev, driver->minor_start,
3167 driver->num, driver->name);
3169 driver->major = MAJOR(dev);
3170 driver->minor_start = MINOR(dev);
3173 dev = MKDEV(driver->major, driver->minor_start);
3174 error = register_chrdev_region(dev, driver->num, driver->name);
3180 driver->ttys = (struct tty_struct **)p;
3181 driver->termios = (struct ktermios **)(p + driver->num);
3183 driver->ttys = NULL;
3184 driver->termios = NULL;
3187 cdev_init(&driver->cdev, &tty_fops);
3188 driver->cdev.owner = driver->owner;
3189 error = cdev_add(&driver->cdev, dev, driver->num);
3191 goto err_unreg_char;
3193 mutex_lock(&tty_mutex);
3194 list_add(&driver->tty_drivers, &tty_drivers);
3195 mutex_unlock(&tty_mutex);
3197 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3198 for (i = 0; i < driver->num; i++) {
3199 d = tty_register_device(driver, i, NULL);
3206 proc_tty_register_driver(driver);
3207 driver->flags |= TTY_DRIVER_INSTALLED;
3211 for (i--; i >= 0; i--)
3212 tty_unregister_device(driver, i);
3214 mutex_lock(&tty_mutex);
3215 list_del(&driver->tty_drivers);
3216 mutex_unlock(&tty_mutex);
3219 unregister_chrdev_region(dev, driver->num);
3220 driver->ttys = NULL;
3221 driver->termios = NULL;
3222 err_free_p: /* destruct_tty_driver will free driver->ports */
3226 EXPORT_SYMBOL(tty_register_driver);
3229 * Called by a tty driver to unregister itself.
3231 int tty_unregister_driver(struct tty_driver *driver)
3235 if (driver->refcount)
3238 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3240 mutex_lock(&tty_mutex);
3241 list_del(&driver->tty_drivers);
3242 mutex_unlock(&tty_mutex);
3246 EXPORT_SYMBOL(tty_unregister_driver);
3248 dev_t tty_devnum(struct tty_struct *tty)
3250 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3252 EXPORT_SYMBOL(tty_devnum);
3254 void proc_clear_tty(struct task_struct *p)
3256 unsigned long flags;
3257 struct tty_struct *tty;
3258 spin_lock_irqsave(&p->sighand->siglock, flags);
3259 tty = p->signal->tty;
3260 p->signal->tty = NULL;
3261 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3265 /* Called under the sighand lock */
3267 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3270 unsigned long flags;
3271 /* We should not have a session or pgrp to put here but.... */
3272 spin_lock_irqsave(&tty->ctrl_lock, flags);
3273 put_pid(tty->session);
3275 tty->pgrp = get_pid(task_pgrp(tsk));
3276 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3277 tty->session = get_pid(task_session(tsk));
3278 if (tsk->signal->tty) {
3279 printk(KERN_DEBUG "tty not NULL!!\n");
3280 tty_kref_put(tsk->signal->tty);
3283 put_pid(tsk->signal->tty_old_pgrp);
3284 tsk->signal->tty = tty_kref_get(tty);
3285 tsk->signal->tty_old_pgrp = NULL;
3288 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3290 spin_lock_irq(&tsk->sighand->siglock);
3291 __proc_set_tty(tsk, tty);
3292 spin_unlock_irq(&tsk->sighand->siglock);
3295 struct tty_struct *get_current_tty(void)
3297 struct tty_struct *tty;
3298 unsigned long flags;
3300 spin_lock_irqsave(¤t->sighand->siglock, flags);
3301 tty = tty_kref_get(current->signal->tty);
3302 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3305 EXPORT_SYMBOL_GPL(get_current_tty);
3307 void tty_default_fops(struct file_operations *fops)
3313 * Initialize the console device. This is called *early*, so
3314 * we can't necessarily depend on lots of kernel help here.
3315 * Just do some early initializations, and do the complex setup
3318 void __init console_init(void)
3322 /* Setup the default TTY line discipline. */
3326 * set up the console device so that later boot sequences can
3327 * inform about problems etc..
3329 call = __con_initcall_start;
3330 while (call < __con_initcall_end) {
3336 static char *tty_devnode(struct device *dev, umode_t *mode)
3340 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3341 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3346 static int __init tty_class_init(void)
3348 tty_class = class_create(THIS_MODULE, "tty");
3349 if (IS_ERR(tty_class))
3350 return PTR_ERR(tty_class);
3351 tty_class->devnode = tty_devnode;
3355 postcore_initcall(tty_class_init);
3357 /* 3/2004 jmc: why do these devices exist? */
3358 static struct cdev tty_cdev, console_cdev;
3360 static ssize_t show_cons_active(struct device *dev,
3361 struct device_attribute *attr, char *buf)
3363 struct console *cs[16];
3369 for_each_console(c) {
3374 if ((c->flags & CON_ENABLED) == 0)
3377 if (i >= ARRAY_SIZE(cs))
3381 count += sprintf(buf + count, "%s%d%c",
3382 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3387 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3389 static struct device *consdev;
3391 void console_sysfs_notify(void)
3394 sysfs_notify(&consdev->kobj, NULL, "active");
3398 * Ok, now we can initialize the rest of the tty devices and can count
3399 * on memory allocations, interrupts etc..
3401 int __init tty_init(void)
3403 cdev_init(&tty_cdev, &tty_fops);
3404 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3405 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3406 panic("Couldn't register /dev/tty driver\n");
3407 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3409 cdev_init(&console_cdev, &console_fops);
3410 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3411 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3412 panic("Couldn't register /dev/console driver\n");
3413 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3415 if (IS_ERR(consdev))
3418 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3421 vty_init(&console_fops);