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 * Structures all installed ... call the ldisc open routines.
1414 * If we fail here just call release_tty to clean up. No need
1415 * to decrement the use counts, as release_tty doesn't care.
1417 retval = tty_ldisc_setup(tty, tty->link);
1419 goto err_release_tty;
1420 /* Return the tty locked so that it cannot vanish under the caller */
1425 deinitialize_tty_struct(tty);
1426 free_tty_struct(tty);
1428 module_put(driver->owner);
1429 return ERR_PTR(retval);
1431 /* call the tty release_tty routine to clean out this slot */
1434 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1435 "clearing slot %d\n", idx);
1436 release_tty(tty, idx);
1437 return ERR_PTR(retval);
1440 void tty_free_termios(struct tty_struct *tty)
1442 struct ktermios *tp;
1443 int idx = tty->index;
1444 /* Kill this flag and push into drivers for locking etc */
1445 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1446 /* FIXME: Locking on ->termios array */
1448 tty->driver->termios[idx] = NULL;
1452 EXPORT_SYMBOL(tty_free_termios);
1454 void tty_shutdown(struct tty_struct *tty)
1456 tty_driver_remove_tty(tty->driver, tty);
1457 tty_free_termios(tty);
1459 EXPORT_SYMBOL(tty_shutdown);
1462 * release_one_tty - release tty structure memory
1463 * @kref: kref of tty we are obliterating
1465 * Releases memory associated with a tty structure, and clears out the
1466 * driver table slots. This function is called when a device is no longer
1467 * in use. It also gets called when setup of a device fails.
1470 * tty_mutex - sometimes only
1471 * takes the file list lock internally when working on the list
1472 * of ttys that the driver keeps.
1474 * This method gets called from a work queue so that the driver private
1475 * cleanup ops can sleep (needed for USB at least)
1477 static void release_one_tty(struct work_struct *work)
1479 struct tty_struct *tty =
1480 container_of(work, struct tty_struct, hangup_work);
1481 struct tty_driver *driver = tty->driver;
1483 if (tty->ops->cleanup)
1484 tty->ops->cleanup(tty);
1487 tty_driver_kref_put(driver);
1488 module_put(driver->owner);
1490 spin_lock(&tty_files_lock);
1491 list_del_init(&tty->tty_files);
1492 spin_unlock(&tty_files_lock);
1495 put_pid(tty->session);
1496 free_tty_struct(tty);
1499 static void queue_release_one_tty(struct kref *kref)
1501 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1503 if (tty->ops->shutdown)
1504 tty->ops->shutdown(tty);
1508 /* The hangup queue is now free so we can reuse it rather than
1509 waste a chunk of memory for each port */
1510 INIT_WORK(&tty->hangup_work, release_one_tty);
1511 schedule_work(&tty->hangup_work);
1515 * tty_kref_put - release a tty kref
1518 * Release a reference to a tty device and if need be let the kref
1519 * layer destruct the object for us
1522 void tty_kref_put(struct tty_struct *tty)
1525 kref_put(&tty->kref, queue_release_one_tty);
1527 EXPORT_SYMBOL(tty_kref_put);
1530 * release_tty - release tty structure memory
1532 * Release both @tty and a possible linked partner (think pty pair),
1533 * and decrement the refcount of the backing module.
1536 * tty_mutex - sometimes only
1537 * takes the file list lock internally when working on the list
1538 * of ttys that the driver keeps.
1539 * FIXME: should we require tty_mutex is held here ??
1542 static void release_tty(struct tty_struct *tty, int idx)
1544 /* This should always be true but check for the moment */
1545 WARN_ON(tty->index != idx);
1548 tty_kref_put(tty->link);
1553 * tty_release_checks - check a tty before real release
1554 * @tty: tty to check
1555 * @o_tty: link of @tty (if any)
1556 * @idx: index of the tty
1558 * Performs some paranoid checking before true release of the @tty.
1559 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1561 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1564 #ifdef TTY_PARANOIA_CHECK
1565 if (idx < 0 || idx >= tty->driver->num) {
1566 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1567 __func__, tty->name);
1571 /* not much to check for devpts */
1572 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1575 if (tty != tty->driver->ttys[idx]) {
1576 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1577 __func__, idx, tty->name);
1580 if (tty->termios != tty->driver->termios[idx]) {
1581 printk(KERN_DEBUG "%s: driver.termios[%d] not termios for (%s)\n",
1582 __func__, idx, tty->name);
1585 if (tty->driver->other) {
1586 if (o_tty != tty->driver->other->ttys[idx]) {
1587 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1588 __func__, idx, tty->name);
1591 if (o_tty->termios != tty->driver->other->termios[idx]) {
1592 printk(KERN_DEBUG "%s: other->termios[%d] not o_termios for (%s)\n",
1593 __func__, idx, tty->name);
1596 if (o_tty->link != tty) {
1597 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1606 * tty_release - vfs callback for close
1607 * @inode: inode of tty
1608 * @filp: file pointer for handle to tty
1610 * Called the last time each file handle is closed that references
1611 * this tty. There may however be several such references.
1614 * Takes bkl. See tty_release_dev
1616 * Even releasing the tty structures is a tricky business.. We have
1617 * to be very careful that the structures are all released at the
1618 * same time, as interrupts might otherwise get the wrong pointers.
1620 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1621 * lead to double frees or releasing memory still in use.
1624 int tty_release(struct inode *inode, struct file *filp)
1626 struct tty_struct *tty = file_tty(filp);
1627 struct tty_struct *o_tty;
1628 int pty_master, tty_closing, o_tty_closing, do_sleep;
1633 if (tty_paranoia_check(tty, inode, __func__))
1637 check_tty_count(tty, __func__);
1639 __tty_fasync(-1, filp, 0);
1642 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1643 tty->driver->subtype == PTY_TYPE_MASTER);
1644 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1645 /* Review: parallel close */
1648 if (tty_release_checks(tty, o_tty, idx)) {
1653 #ifdef TTY_DEBUG_HANGUP
1654 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1655 tty_name(tty, buf), tty->count);
1658 if (tty->ops->close)
1659 tty->ops->close(tty, filp);
1663 * Sanity check: if tty->count is going to zero, there shouldn't be
1664 * any waiters on tty->read_wait or tty->write_wait. We test the
1665 * wait queues and kick everyone out _before_ actually starting to
1666 * close. This ensures that we won't block while releasing the tty
1669 * The test for the o_tty closing is necessary, since the master and
1670 * slave sides may close in any order. If the slave side closes out
1671 * first, its count will be one, since the master side holds an open.
1672 * Thus this test wouldn't be triggered at the time the slave closes,
1675 * Note that it's possible for the tty to be opened again while we're
1676 * flushing out waiters. By recalculating the closing flags before
1677 * each iteration we avoid any problems.
1680 /* Guard against races with tty->count changes elsewhere and
1681 opens on /dev/tty */
1683 mutex_lock(&tty_mutex);
1684 tty_lock_pair(tty, o_tty);
1685 tty_closing = tty->count <= 1;
1686 o_tty_closing = o_tty &&
1687 (o_tty->count <= (pty_master ? 1 : 0));
1691 if (waitqueue_active(&tty->read_wait)) {
1692 wake_up_poll(&tty->read_wait, POLLIN);
1695 if (waitqueue_active(&tty->write_wait)) {
1696 wake_up_poll(&tty->write_wait, POLLOUT);
1700 if (o_tty_closing) {
1701 if (waitqueue_active(&o_tty->read_wait)) {
1702 wake_up_poll(&o_tty->read_wait, POLLIN);
1705 if (waitqueue_active(&o_tty->write_wait)) {
1706 wake_up_poll(&o_tty->write_wait, POLLOUT);
1713 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1714 __func__, tty_name(tty, buf));
1715 tty_unlock_pair(tty, o_tty);
1716 mutex_unlock(&tty_mutex);
1721 * The closing flags are now consistent with the open counts on
1722 * both sides, and we've completed the last operation that could
1723 * block, so it's safe to proceed with closing.
1726 if (--o_tty->count < 0) {
1727 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1728 __func__, o_tty->count, tty_name(o_tty, buf));
1732 if (--tty->count < 0) {
1733 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1734 __func__, tty->count, tty_name(tty, buf));
1739 * We've decremented tty->count, so we need to remove this file
1740 * descriptor off the tty->tty_files list; this serves two
1742 * - check_tty_count sees the correct number of file descriptors
1743 * associated with this tty.
1744 * - do_tty_hangup no longer sees this file descriptor as
1745 * something that needs to be handled for hangups.
1750 * Perform some housekeeping before deciding whether to return.
1752 * Set the TTY_CLOSING flag if this was the last open. In the
1753 * case of a pty we may have to wait around for the other side
1754 * to close, and TTY_CLOSING makes sure we can't be reopened.
1757 set_bit(TTY_CLOSING, &tty->flags);
1759 set_bit(TTY_CLOSING, &o_tty->flags);
1762 * If _either_ side is closing, make sure there aren't any
1763 * processes that still think tty or o_tty is their controlling
1766 if (tty_closing || o_tty_closing) {
1767 read_lock(&tasklist_lock);
1768 session_clear_tty(tty->session);
1770 session_clear_tty(o_tty->session);
1771 read_unlock(&tasklist_lock);
1774 mutex_unlock(&tty_mutex);
1776 /* check whether both sides are closing ... */
1777 if (!tty_closing || (o_tty && !o_tty_closing)) {
1778 tty_unlock_pair(tty, o_tty);
1782 #ifdef TTY_DEBUG_HANGUP
1783 printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__);
1786 * Ask the line discipline code to release its structures
1788 tty_ldisc_release(tty, o_tty);
1790 * The release_tty function takes care of the details of clearing
1791 * the slots and preserving the termios structure. The tty_unlock_pair
1792 * should be safe as we keep a kref while the tty is locked (so the
1793 * unlock never unlocks a freed tty).
1795 release_tty(tty, idx);
1796 tty_unlock_pair(tty, o_tty);
1798 /* Make this pty number available for reallocation */
1800 devpts_kill_index(inode, idx);
1805 * tty_open_current_tty - get tty of current task for open
1806 * @device: device number
1807 * @filp: file pointer to tty
1808 * @return: tty of the current task iff @device is /dev/tty
1810 * We cannot return driver and index like for the other nodes because
1811 * devpts will not work then. It expects inodes to be from devpts FS.
1813 * We need to move to returning a refcounted object from all the lookup
1814 * paths including this one.
1816 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1818 struct tty_struct *tty;
1820 if (device != MKDEV(TTYAUX_MAJOR, 0))
1823 tty = get_current_tty();
1825 return ERR_PTR(-ENXIO);
1827 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1830 /* FIXME: we put a reference and return a TTY! */
1831 /* This is only safe because the caller holds tty_mutex */
1836 * tty_lookup_driver - lookup a tty driver for a given device file
1837 * @device: device number
1838 * @filp: file pointer to tty
1839 * @noctty: set if the device should not become a controlling tty
1840 * @index: index for the device in the @return driver
1841 * @return: driver for this inode (with increased refcount)
1843 * If @return is not erroneous, the caller is responsible to decrement the
1844 * refcount by tty_driver_kref_put.
1846 * Locking: tty_mutex protects get_tty_driver
1848 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1849 int *noctty, int *index)
1851 struct tty_driver *driver;
1855 case MKDEV(TTY_MAJOR, 0): {
1856 extern struct tty_driver *console_driver;
1857 driver = tty_driver_kref_get(console_driver);
1858 *index = fg_console;
1863 case MKDEV(TTYAUX_MAJOR, 1): {
1864 struct tty_driver *console_driver = console_device(index);
1865 if (console_driver) {
1866 driver = tty_driver_kref_get(console_driver);
1868 /* Don't let /dev/console block */
1869 filp->f_flags |= O_NONBLOCK;
1874 return ERR_PTR(-ENODEV);
1877 driver = get_tty_driver(device, index);
1879 return ERR_PTR(-ENODEV);
1886 * tty_open - open a tty device
1887 * @inode: inode of device file
1888 * @filp: file pointer to tty
1890 * tty_open and tty_release keep up the tty count that contains the
1891 * number of opens done on a tty. We cannot use the inode-count, as
1892 * different inodes might point to the same tty.
1894 * Open-counting is needed for pty masters, as well as for keeping
1895 * track of serial lines: DTR is dropped when the last close happens.
1896 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1898 * The termios state of a pty is reset on first open so that
1899 * settings don't persist across reuse.
1901 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1902 * tty->count should protect the rest.
1903 * ->siglock protects ->signal/->sighand
1905 * Note: the tty_unlock/lock cases without a ref are only safe due to
1909 static int tty_open(struct inode *inode, struct file *filp)
1911 struct tty_struct *tty;
1913 struct tty_driver *driver = NULL;
1915 dev_t device = inode->i_rdev;
1916 unsigned saved_flags = filp->f_flags;
1918 nonseekable_open(inode, filp);
1921 retval = tty_alloc_file(filp);
1925 noctty = filp->f_flags & O_NOCTTY;
1929 mutex_lock(&tty_mutex);
1930 /* This is protected by the tty_mutex */
1931 tty = tty_open_current_tty(device, filp);
1933 retval = PTR_ERR(tty);
1936 driver = tty_lookup_driver(device, filp, &noctty, &index);
1937 if (IS_ERR(driver)) {
1938 retval = PTR_ERR(driver);
1942 /* check whether we're reopening an existing tty */
1943 tty = tty_driver_lookup_tty(driver, inode, index);
1945 retval = PTR_ERR(tty);
1952 retval = tty_reopen(tty);
1955 tty = ERR_PTR(retval);
1957 } else /* Returns with the tty_lock held for now */
1958 tty = tty_init_dev(driver, index);
1960 mutex_unlock(&tty_mutex);
1962 tty_driver_kref_put(driver);
1964 retval = PTR_ERR(tty);
1968 tty_add_file(tty, filp);
1970 check_tty_count(tty, __func__);
1971 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1972 tty->driver->subtype == PTY_TYPE_MASTER)
1974 #ifdef TTY_DEBUG_HANGUP
1975 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
1978 retval = tty->ops->open(tty, filp);
1981 filp->f_flags = saved_flags;
1983 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1984 !capable(CAP_SYS_ADMIN))
1988 #ifdef TTY_DEBUG_HANGUP
1989 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
1992 tty_unlock(tty); /* need to call tty_release without BTM */
1993 tty_release(inode, filp);
1994 if (retval != -ERESTARTSYS)
1997 if (signal_pending(current))
2002 * Need to reset f_op in case a hangup happened.
2004 if (filp->f_op == &hung_up_tty_fops)
2005 filp->f_op = &tty_fops;
2011 mutex_lock(&tty_mutex);
2013 spin_lock_irq(¤t->sighand->siglock);
2015 current->signal->leader &&
2016 !current->signal->tty &&
2017 tty->session == NULL)
2018 __proc_set_tty(current, tty);
2019 spin_unlock_irq(¤t->sighand->siglock);
2021 mutex_unlock(&tty_mutex);
2024 mutex_unlock(&tty_mutex);
2025 /* after locks to avoid deadlock */
2026 if (!IS_ERR_OR_NULL(driver))
2027 tty_driver_kref_put(driver);
2029 tty_free_file(filp);
2036 * tty_poll - check tty status
2037 * @filp: file being polled
2038 * @wait: poll wait structures to update
2040 * Call the line discipline polling method to obtain the poll
2041 * status of the device.
2043 * Locking: locks called line discipline but ldisc poll method
2044 * may be re-entered freely by other callers.
2047 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2049 struct tty_struct *tty = file_tty(filp);
2050 struct tty_ldisc *ld;
2053 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
2056 ld = tty_ldisc_ref_wait(tty);
2058 ret = (ld->ops->poll)(tty, filp, wait);
2059 tty_ldisc_deref(ld);
2063 static int __tty_fasync(int fd, struct file *filp, int on)
2065 struct tty_struct *tty = file_tty(filp);
2066 unsigned long flags;
2069 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
2072 retval = fasync_helper(fd, filp, on, &tty->fasync);
2079 if (!waitqueue_active(&tty->read_wait))
2080 tty->minimum_to_wake = 1;
2081 spin_lock_irqsave(&tty->ctrl_lock, flags);
2084 type = PIDTYPE_PGID;
2086 pid = task_pid(current);
2090 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2091 retval = __f_setown(filp, pid, type, 0);
2096 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2097 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2104 static int tty_fasync(int fd, struct file *filp, int on)
2106 struct tty_struct *tty = file_tty(filp);
2110 retval = __tty_fasync(fd, filp, on);
2117 * tiocsti - fake input character
2118 * @tty: tty to fake input into
2119 * @p: pointer to character
2121 * Fake input to a tty device. Does the necessary locking and
2124 * FIXME: does not honour flow control ??
2127 * Called functions take tty_ldisc_lock
2128 * current->signal->tty check is safe without locks
2130 * FIXME: may race normal receive processing
2133 static int tiocsti(struct tty_struct *tty, char __user *p)
2136 struct tty_ldisc *ld;
2138 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2140 if (get_user(ch, p))
2142 tty_audit_tiocsti(tty, ch);
2143 ld = tty_ldisc_ref_wait(tty);
2144 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2145 tty_ldisc_deref(ld);
2150 * tiocgwinsz - implement window query ioctl
2152 * @arg: user buffer for result
2154 * Copies the kernel idea of the window size into the user buffer.
2156 * Locking: tty->termios_mutex is taken to ensure the winsize data
2160 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2164 mutex_lock(&tty->termios_mutex);
2165 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2166 mutex_unlock(&tty->termios_mutex);
2168 return err ? -EFAULT: 0;
2172 * tty_do_resize - resize event
2173 * @tty: tty being resized
2174 * @rows: rows (character)
2175 * @cols: cols (character)
2177 * Update the termios variables and send the necessary signals to
2178 * peform a terminal resize correctly
2181 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2184 unsigned long flags;
2187 mutex_lock(&tty->termios_mutex);
2188 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2190 /* Get the PID values and reference them so we can
2191 avoid holding the tty ctrl lock while sending signals */
2192 spin_lock_irqsave(&tty->ctrl_lock, flags);
2193 pgrp = get_pid(tty->pgrp);
2194 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2197 kill_pgrp(pgrp, SIGWINCH, 1);
2202 mutex_unlock(&tty->termios_mutex);
2207 * tiocswinsz - implement window size set ioctl
2208 * @tty; tty side of tty
2209 * @arg: user buffer for result
2211 * Copies the user idea of the window size to the kernel. Traditionally
2212 * this is just advisory information but for the Linux console it
2213 * actually has driver level meaning and triggers a VC resize.
2216 * Driver dependent. The default do_resize method takes the
2217 * tty termios mutex and ctrl_lock. The console takes its own lock
2218 * then calls into the default method.
2221 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2223 struct winsize tmp_ws;
2224 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2227 if (tty->ops->resize)
2228 return tty->ops->resize(tty, &tmp_ws);
2230 return tty_do_resize(tty, &tmp_ws);
2234 * tioccons - allow admin to move logical console
2235 * @file: the file to become console
2237 * Allow the administrator to move the redirected console device
2239 * Locking: uses redirect_lock to guard the redirect information
2242 static int tioccons(struct file *file)
2244 if (!capable(CAP_SYS_ADMIN))
2246 if (file->f_op->write == redirected_tty_write) {
2248 spin_lock(&redirect_lock);
2251 spin_unlock(&redirect_lock);
2256 spin_lock(&redirect_lock);
2258 spin_unlock(&redirect_lock);
2263 spin_unlock(&redirect_lock);
2268 * fionbio - non blocking ioctl
2269 * @file: file to set blocking value
2270 * @p: user parameter
2272 * Historical tty interfaces had a blocking control ioctl before
2273 * the generic functionality existed. This piece of history is preserved
2274 * in the expected tty API of posix OS's.
2276 * Locking: none, the open file handle ensures it won't go away.
2279 static int fionbio(struct file *file, int __user *p)
2283 if (get_user(nonblock, p))
2286 spin_lock(&file->f_lock);
2288 file->f_flags |= O_NONBLOCK;
2290 file->f_flags &= ~O_NONBLOCK;
2291 spin_unlock(&file->f_lock);
2296 * tiocsctty - set controlling tty
2297 * @tty: tty structure
2298 * @arg: user argument
2300 * This ioctl is used to manage job control. It permits a session
2301 * leader to set this tty as the controlling tty for the session.
2304 * Takes tty_mutex() to protect tty instance
2305 * Takes tasklist_lock internally to walk sessions
2306 * Takes ->siglock() when updating signal->tty
2309 static int tiocsctty(struct tty_struct *tty, int arg)
2312 if (current->signal->leader && (task_session(current) == tty->session))
2315 mutex_lock(&tty_mutex);
2317 * The process must be a session leader and
2318 * not have a controlling tty already.
2320 if (!current->signal->leader || current->signal->tty) {
2327 * This tty is already the controlling
2328 * tty for another session group!
2330 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2334 read_lock(&tasklist_lock);
2335 session_clear_tty(tty->session);
2336 read_unlock(&tasklist_lock);
2342 proc_set_tty(current, tty);
2344 mutex_unlock(&tty_mutex);
2349 * tty_get_pgrp - return a ref counted pgrp pid
2352 * Returns a refcounted instance of the pid struct for the process
2353 * group controlling the tty.
2356 struct pid *tty_get_pgrp(struct tty_struct *tty)
2358 unsigned long flags;
2361 spin_lock_irqsave(&tty->ctrl_lock, flags);
2362 pgrp = get_pid(tty->pgrp);
2363 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2367 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2370 * tiocgpgrp - get process group
2371 * @tty: tty passed by user
2372 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2375 * Obtain the process group of the tty. If there is no process group
2378 * Locking: none. Reference to current->signal->tty is safe.
2381 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2386 * (tty == real_tty) is a cheap way of
2387 * testing if the tty is NOT a master pty.
2389 if (tty == real_tty && current->signal->tty != real_tty)
2391 pid = tty_get_pgrp(real_tty);
2392 ret = put_user(pid_vnr(pid), p);
2398 * tiocspgrp - attempt to set process group
2399 * @tty: tty passed by user
2400 * @real_tty: tty side device matching tty passed by user
2403 * Set the process group of the tty to the session passed. Only
2404 * permitted where the tty session is our session.
2406 * Locking: RCU, ctrl lock
2409 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2413 int retval = tty_check_change(real_tty);
2414 unsigned long flags;
2420 if (!current->signal->tty ||
2421 (current->signal->tty != real_tty) ||
2422 (real_tty->session != task_session(current)))
2424 if (get_user(pgrp_nr, p))
2429 pgrp = find_vpid(pgrp_nr);
2434 if (session_of_pgrp(pgrp) != task_session(current))
2437 spin_lock_irqsave(&tty->ctrl_lock, flags);
2438 put_pid(real_tty->pgrp);
2439 real_tty->pgrp = get_pid(pgrp);
2440 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2447 * tiocgsid - get session id
2448 * @tty: tty passed by user
2449 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2450 * @p: pointer to returned session id
2452 * Obtain the session id of the tty. If there is no session
2455 * Locking: none. Reference to current->signal->tty is safe.
2458 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2461 * (tty == real_tty) is a cheap way of
2462 * testing if the tty is NOT a master pty.
2464 if (tty == real_tty && current->signal->tty != real_tty)
2466 if (!real_tty->session)
2468 return put_user(pid_vnr(real_tty->session), p);
2472 * tiocsetd - set line discipline
2474 * @p: pointer to user data
2476 * Set the line discipline according to user request.
2478 * Locking: see tty_set_ldisc, this function is just a helper
2481 static int tiocsetd(struct tty_struct *tty, int __user *p)
2486 if (get_user(ldisc, p))
2489 ret = tty_set_ldisc(tty, ldisc);
2495 * send_break - performed time break
2496 * @tty: device to break on
2497 * @duration: timeout in mS
2499 * Perform a timed break on hardware that lacks its own driver level
2500 * timed break functionality.
2503 * atomic_write_lock serializes
2507 static int send_break(struct tty_struct *tty, unsigned int duration)
2511 if (tty->ops->break_ctl == NULL)
2514 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2515 retval = tty->ops->break_ctl(tty, duration);
2517 /* Do the work ourselves */
2518 if (tty_write_lock(tty, 0) < 0)
2520 retval = tty->ops->break_ctl(tty, -1);
2523 if (!signal_pending(current))
2524 msleep_interruptible(duration);
2525 retval = tty->ops->break_ctl(tty, 0);
2527 tty_write_unlock(tty);
2528 if (signal_pending(current))
2535 * tty_tiocmget - get modem status
2537 * @file: user file pointer
2538 * @p: pointer to result
2540 * Obtain the modem status bits from the tty driver if the feature
2541 * is supported. Return -EINVAL if it is not available.
2543 * Locking: none (up to the driver)
2546 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2548 int retval = -EINVAL;
2550 if (tty->ops->tiocmget) {
2551 retval = tty->ops->tiocmget(tty);
2554 retval = put_user(retval, p);
2560 * tty_tiocmset - set modem status
2562 * @cmd: command - clear bits, set bits or set all
2563 * @p: pointer to desired bits
2565 * Set the modem status bits from the tty driver if the feature
2566 * is supported. Return -EINVAL if it is not available.
2568 * Locking: none (up to the driver)
2571 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2575 unsigned int set, clear, val;
2577 if (tty->ops->tiocmset == NULL)
2580 retval = get_user(val, p);
2596 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2597 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2598 return tty->ops->tiocmset(tty, set, clear);
2601 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2603 int retval = -EINVAL;
2604 struct serial_icounter_struct icount;
2605 memset(&icount, 0, sizeof(icount));
2606 if (tty->ops->get_icount)
2607 retval = tty->ops->get_icount(tty, &icount);
2610 if (copy_to_user(arg, &icount, sizeof(icount)))
2615 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2617 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2618 tty->driver->subtype == PTY_TYPE_MASTER)
2622 EXPORT_SYMBOL(tty_pair_get_tty);
2624 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2626 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2627 tty->driver->subtype == PTY_TYPE_MASTER)
2631 EXPORT_SYMBOL(tty_pair_get_pty);
2634 * Split this up, as gcc can choke on it otherwise..
2636 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2638 struct tty_struct *tty = file_tty(file);
2639 struct tty_struct *real_tty;
2640 void __user *p = (void __user *)arg;
2642 struct tty_ldisc *ld;
2643 struct inode *inode = file->f_dentry->d_inode;
2645 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2648 real_tty = tty_pair_get_tty(tty);
2651 * Factor out some common prep work
2659 retval = tty_check_change(tty);
2662 if (cmd != TIOCCBRK) {
2663 tty_wait_until_sent(tty, 0);
2664 if (signal_pending(current))
2675 return tiocsti(tty, p);
2677 return tiocgwinsz(real_tty, p);
2679 return tiocswinsz(real_tty, p);
2681 return real_tty != tty ? -EINVAL : tioccons(file);
2683 return fionbio(file, p);
2685 set_bit(TTY_EXCLUSIVE, &tty->flags);
2688 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2691 if (current->signal->tty != tty)
2696 return tiocsctty(tty, arg);
2698 return tiocgpgrp(tty, real_tty, p);
2700 return tiocspgrp(tty, real_tty, p);
2702 return tiocgsid(tty, real_tty, p);
2704 return put_user(tty->ldisc->ops->num, (int __user *)p);
2706 return tiocsetd(tty, p);
2708 if (!capable(CAP_SYS_ADMIN))
2714 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2715 return put_user(ret, (unsigned int __user *)p);
2720 case TIOCSBRK: /* Turn break on, unconditionally */
2721 if (tty->ops->break_ctl)
2722 return tty->ops->break_ctl(tty, -1);
2724 case TIOCCBRK: /* Turn break off, unconditionally */
2725 if (tty->ops->break_ctl)
2726 return tty->ops->break_ctl(tty, 0);
2728 case TCSBRK: /* SVID version: non-zero arg --> no break */
2729 /* non-zero arg means wait for all output data
2730 * to be sent (performed above) but don't send break.
2731 * This is used by the tcdrain() termios function.
2734 return send_break(tty, 250);
2736 case TCSBRKP: /* support for POSIX tcsendbreak() */
2737 return send_break(tty, arg ? arg*100 : 250);
2740 return tty_tiocmget(tty, p);
2744 return tty_tiocmset(tty, cmd, p);
2746 retval = tty_tiocgicount(tty, p);
2747 /* For the moment allow fall through to the old method */
2748 if (retval != -EINVAL)
2755 /* flush tty buffer and allow ldisc to process ioctl */
2756 tty_buffer_flush(tty);
2761 if (tty->ops->ioctl) {
2762 retval = (tty->ops->ioctl)(tty, cmd, arg);
2763 if (retval != -ENOIOCTLCMD)
2766 ld = tty_ldisc_ref_wait(tty);
2768 if (ld->ops->ioctl) {
2769 retval = ld->ops->ioctl(tty, file, cmd, arg);
2770 if (retval == -ENOIOCTLCMD)
2773 tty_ldisc_deref(ld);
2777 #ifdef CONFIG_COMPAT
2778 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2781 struct inode *inode = file->f_dentry->d_inode;
2782 struct tty_struct *tty = file_tty(file);
2783 struct tty_ldisc *ld;
2784 int retval = -ENOIOCTLCMD;
2786 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2789 if (tty->ops->compat_ioctl) {
2790 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2791 if (retval != -ENOIOCTLCMD)
2795 ld = tty_ldisc_ref_wait(tty);
2796 if (ld->ops->compat_ioctl)
2797 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2799 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2800 tty_ldisc_deref(ld);
2807 * This implements the "Secure Attention Key" --- the idea is to
2808 * prevent trojan horses by killing all processes associated with this
2809 * tty when the user hits the "Secure Attention Key". Required for
2810 * super-paranoid applications --- see the Orange Book for more details.
2812 * This code could be nicer; ideally it should send a HUP, wait a few
2813 * seconds, then send a INT, and then a KILL signal. But you then
2814 * have to coordinate with the init process, since all processes associated
2815 * with the current tty must be dead before the new getty is allowed
2818 * Now, if it would be correct ;-/ The current code has a nasty hole -
2819 * it doesn't catch files in flight. We may send the descriptor to ourselves
2820 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2822 * Nasty bug: do_SAK is being called in interrupt context. This can
2823 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2825 void __do_SAK(struct tty_struct *tty)
2830 struct task_struct *g, *p;
2831 struct pid *session;
2834 struct fdtable *fdt;
2838 session = tty->session;
2840 tty_ldisc_flush(tty);
2842 tty_driver_flush_buffer(tty);
2844 read_lock(&tasklist_lock);
2845 /* Kill the entire session */
2846 do_each_pid_task(session, PIDTYPE_SID, p) {
2847 printk(KERN_NOTICE "SAK: killed process %d"
2848 " (%s): task_session(p)==tty->session\n",
2849 task_pid_nr(p), p->comm);
2850 send_sig(SIGKILL, p, 1);
2851 } while_each_pid_task(session, PIDTYPE_SID, p);
2852 /* Now kill any processes that happen to have the
2855 do_each_thread(g, p) {
2856 if (p->signal->tty == tty) {
2857 printk(KERN_NOTICE "SAK: killed process %d"
2858 " (%s): task_session(p)==tty->session\n",
2859 task_pid_nr(p), p->comm);
2860 send_sig(SIGKILL, p, 1);
2866 * We don't take a ref to the file, so we must
2867 * hold ->file_lock instead.
2869 spin_lock(&p->files->file_lock);
2870 fdt = files_fdtable(p->files);
2871 for (i = 0; i < fdt->max_fds; i++) {
2872 filp = fcheck_files(p->files, i);
2875 if (filp->f_op->read == tty_read &&
2876 file_tty(filp) == tty) {
2877 printk(KERN_NOTICE "SAK: killed process %d"
2878 " (%s): fd#%d opened to the tty\n",
2879 task_pid_nr(p), p->comm, i);
2880 force_sig(SIGKILL, p);
2884 spin_unlock(&p->files->file_lock);
2887 } while_each_thread(g, p);
2888 read_unlock(&tasklist_lock);
2892 static void do_SAK_work(struct work_struct *work)
2894 struct tty_struct *tty =
2895 container_of(work, struct tty_struct, SAK_work);
2900 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2901 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2902 * the values which we write to it will be identical to the values which it
2903 * already has. --akpm
2905 void do_SAK(struct tty_struct *tty)
2909 schedule_work(&tty->SAK_work);
2912 EXPORT_SYMBOL(do_SAK);
2914 static int dev_match_devt(struct device *dev, void *data)
2917 return dev->devt == *devt;
2920 /* Must put_device() after it's unused! */
2921 static struct device *tty_get_device(struct tty_struct *tty)
2923 dev_t devt = tty_devnum(tty);
2924 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2929 * initialize_tty_struct
2930 * @tty: tty to initialize
2932 * This subroutine initializes a tty structure that has been newly
2935 * Locking: none - tty in question must not be exposed at this point
2938 void initialize_tty_struct(struct tty_struct *tty,
2939 struct tty_driver *driver, int idx)
2941 memset(tty, 0, sizeof(struct tty_struct));
2942 kref_init(&tty->kref);
2943 tty->magic = TTY_MAGIC;
2944 tty_ldisc_init(tty);
2945 tty->session = NULL;
2947 tty->overrun_time = jiffies;
2948 tty_buffer_init(tty);
2949 mutex_init(&tty->legacy_mutex);
2950 mutex_init(&tty->termios_mutex);
2951 mutex_init(&tty->ldisc_mutex);
2952 init_waitqueue_head(&tty->write_wait);
2953 init_waitqueue_head(&tty->read_wait);
2954 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2955 mutex_init(&tty->atomic_read_lock);
2956 mutex_init(&tty->atomic_write_lock);
2957 mutex_init(&tty->output_lock);
2958 mutex_init(&tty->echo_lock);
2959 spin_lock_init(&tty->read_lock);
2960 spin_lock_init(&tty->ctrl_lock);
2961 INIT_LIST_HEAD(&tty->tty_files);
2962 INIT_WORK(&tty->SAK_work, do_SAK_work);
2964 tty->driver = driver;
2965 tty->ops = driver->ops;
2967 tty_line_name(driver, idx, tty->name);
2968 tty->dev = tty_get_device(tty);
2972 * deinitialize_tty_struct
2973 * @tty: tty to deinitialize
2975 * This subroutine deinitializes a tty structure that has been newly
2976 * allocated but tty_release cannot be called on that yet.
2978 * Locking: none - tty in question must not be exposed at this point
2980 void deinitialize_tty_struct(struct tty_struct *tty)
2982 tty_ldisc_deinit(tty);
2986 * tty_put_char - write one character to a tty
2990 * Write one byte to the tty using the provided put_char method
2991 * if present. Returns the number of characters successfully output.
2993 * Note: the specific put_char operation in the driver layer may go
2994 * away soon. Don't call it directly, use this method
2997 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2999 if (tty->ops->put_char)
3000 return tty->ops->put_char(tty, ch);
3001 return tty->ops->write(tty, &ch, 1);
3003 EXPORT_SYMBOL_GPL(tty_put_char);
3005 struct class *tty_class;
3008 * tty_register_device - register a tty device
3009 * @driver: the tty driver that describes the tty device
3010 * @index: the index in the tty driver for this tty device
3011 * @device: a struct device that is associated with this tty device.
3012 * This field is optional, if there is no known struct device
3013 * for this tty device it can be set to NULL safely.
3015 * Returns a pointer to the struct device for this tty device
3016 * (or ERR_PTR(-EFOO) on error).
3018 * This call is required to be made to register an individual tty device
3019 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3020 * that bit is not set, this function should not be called by a tty
3026 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3027 struct device *device)
3030 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
3032 if (index >= driver->num) {
3033 printk(KERN_ERR "Attempt to register invalid tty line number "
3035 return ERR_PTR(-EINVAL);
3038 if (driver->type == TTY_DRIVER_TYPE_PTY)
3039 pty_line_name(driver, index, name);
3041 tty_line_name(driver, index, name);
3043 return device_create(tty_class, device, dev, NULL, name);
3045 EXPORT_SYMBOL(tty_register_device);
3048 * tty_unregister_device - unregister a tty device
3049 * @driver: the tty driver that describes the tty device
3050 * @index: the index in the tty driver for this tty device
3052 * If a tty device is registered with a call to tty_register_device() then
3053 * this function must be called when the tty device is gone.
3058 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3060 device_destroy(tty_class,
3061 MKDEV(driver->major, driver->minor_start) + index);
3063 EXPORT_SYMBOL(tty_unregister_device);
3065 struct tty_driver *__alloc_tty_driver(int lines, struct module *owner)
3067 struct tty_driver *driver;
3069 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3071 kref_init(&driver->kref);
3072 driver->magic = TTY_DRIVER_MAGIC;
3073 driver->num = lines;
3074 driver->owner = owner;
3075 /* later we'll move allocation of tables here */
3079 EXPORT_SYMBOL(__alloc_tty_driver);
3081 static void destruct_tty_driver(struct kref *kref)
3083 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3085 struct ktermios *tp;
3088 if (driver->flags & TTY_DRIVER_INSTALLED) {
3090 * Free the termios and termios_locked structures because
3091 * we don't want to get memory leaks when modular tty
3092 * drivers are removed from the kernel.
3094 for (i = 0; i < driver->num; i++) {
3095 tp = driver->termios[i];
3097 driver->termios[i] = NULL;
3100 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3101 tty_unregister_device(driver, i);
3104 proc_tty_unregister_driver(driver);
3105 driver->ttys = NULL;
3106 driver->termios = NULL;
3108 cdev_del(&driver->cdev);
3113 void tty_driver_kref_put(struct tty_driver *driver)
3115 kref_put(&driver->kref, destruct_tty_driver);
3117 EXPORT_SYMBOL(tty_driver_kref_put);
3119 void tty_set_operations(struct tty_driver *driver,
3120 const struct tty_operations *op)
3124 EXPORT_SYMBOL(tty_set_operations);
3126 void put_tty_driver(struct tty_driver *d)
3128 tty_driver_kref_put(d);
3130 EXPORT_SYMBOL(put_tty_driver);
3133 * Called by a tty driver to register itself.
3135 int tty_register_driver(struct tty_driver *driver)
3143 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3144 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3149 if (!driver->major) {
3150 error = alloc_chrdev_region(&dev, driver->minor_start,
3151 driver->num, driver->name);
3153 driver->major = MAJOR(dev);
3154 driver->minor_start = MINOR(dev);
3157 dev = MKDEV(driver->major, driver->minor_start);
3158 error = register_chrdev_region(dev, driver->num, driver->name);
3166 driver->ttys = (struct tty_struct **)p;
3167 driver->termios = (struct ktermios **)(p + driver->num);
3169 driver->ttys = NULL;
3170 driver->termios = NULL;
3173 cdev_init(&driver->cdev, &tty_fops);
3174 driver->cdev.owner = driver->owner;
3175 error = cdev_add(&driver->cdev, dev, driver->num);
3177 unregister_chrdev_region(dev, driver->num);
3178 driver->ttys = NULL;
3179 driver->termios = NULL;
3184 mutex_lock(&tty_mutex);
3185 list_add(&driver->tty_drivers, &tty_drivers);
3186 mutex_unlock(&tty_mutex);
3188 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3189 for (i = 0; i < driver->num; i++) {
3190 d = tty_register_device(driver, i, NULL);
3197 proc_tty_register_driver(driver);
3198 driver->flags |= TTY_DRIVER_INSTALLED;
3202 for (i--; i >= 0; i--)
3203 tty_unregister_device(driver, i);
3205 mutex_lock(&tty_mutex);
3206 list_del(&driver->tty_drivers);
3207 mutex_unlock(&tty_mutex);
3209 unregister_chrdev_region(dev, driver->num);
3210 driver->ttys = NULL;
3211 driver->termios = NULL;
3216 EXPORT_SYMBOL(tty_register_driver);
3219 * Called by a tty driver to unregister itself.
3221 int tty_unregister_driver(struct tty_driver *driver)
3225 if (driver->refcount)
3228 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3230 mutex_lock(&tty_mutex);
3231 list_del(&driver->tty_drivers);
3232 mutex_unlock(&tty_mutex);
3236 EXPORT_SYMBOL(tty_unregister_driver);
3238 dev_t tty_devnum(struct tty_struct *tty)
3240 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3242 EXPORT_SYMBOL(tty_devnum);
3244 void proc_clear_tty(struct task_struct *p)
3246 unsigned long flags;
3247 struct tty_struct *tty;
3248 spin_lock_irqsave(&p->sighand->siglock, flags);
3249 tty = p->signal->tty;
3250 p->signal->tty = NULL;
3251 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3255 /* Called under the sighand lock */
3257 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3260 unsigned long flags;
3261 /* We should not have a session or pgrp to put here but.... */
3262 spin_lock_irqsave(&tty->ctrl_lock, flags);
3263 put_pid(tty->session);
3265 tty->pgrp = get_pid(task_pgrp(tsk));
3266 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3267 tty->session = get_pid(task_session(tsk));
3268 if (tsk->signal->tty) {
3269 printk(KERN_DEBUG "tty not NULL!!\n");
3270 tty_kref_put(tsk->signal->tty);
3273 put_pid(tsk->signal->tty_old_pgrp);
3274 tsk->signal->tty = tty_kref_get(tty);
3275 tsk->signal->tty_old_pgrp = NULL;
3278 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3280 spin_lock_irq(&tsk->sighand->siglock);
3281 __proc_set_tty(tsk, tty);
3282 spin_unlock_irq(&tsk->sighand->siglock);
3285 struct tty_struct *get_current_tty(void)
3287 struct tty_struct *tty;
3288 unsigned long flags;
3290 spin_lock_irqsave(¤t->sighand->siglock, flags);
3291 tty = tty_kref_get(current->signal->tty);
3292 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3295 EXPORT_SYMBOL_GPL(get_current_tty);
3297 void tty_default_fops(struct file_operations *fops)
3303 * Initialize the console device. This is called *early*, so
3304 * we can't necessarily depend on lots of kernel help here.
3305 * Just do some early initializations, and do the complex setup
3308 void __init console_init(void)
3312 /* Setup the default TTY line discipline. */
3316 * set up the console device so that later boot sequences can
3317 * inform about problems etc..
3319 call = __con_initcall_start;
3320 while (call < __con_initcall_end) {
3326 static char *tty_devnode(struct device *dev, umode_t *mode)
3330 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3331 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3336 static int __init tty_class_init(void)
3338 tty_class = class_create(THIS_MODULE, "tty");
3339 if (IS_ERR(tty_class))
3340 return PTR_ERR(tty_class);
3341 tty_class->devnode = tty_devnode;
3345 postcore_initcall(tty_class_init);
3347 /* 3/2004 jmc: why do these devices exist? */
3348 static struct cdev tty_cdev, console_cdev;
3350 static ssize_t show_cons_active(struct device *dev,
3351 struct device_attribute *attr, char *buf)
3353 struct console *cs[16];
3359 for_each_console(c) {
3364 if ((c->flags & CON_ENABLED) == 0)
3367 if (i >= ARRAY_SIZE(cs))
3371 count += sprintf(buf + count, "%s%d%c",
3372 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3377 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3379 static struct device *consdev;
3381 void console_sysfs_notify(void)
3384 sysfs_notify(&consdev->kobj, NULL, "active");
3388 * Ok, now we can initialize the rest of the tty devices and can count
3389 * on memory allocations, interrupts etc..
3391 int __init tty_init(void)
3393 cdev_init(&tty_cdev, &tty_fops);
3394 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3395 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3396 panic("Couldn't register /dev/tty driver\n");
3397 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3399 cdev_init(&console_cdev, &console_fops);
3400 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3401 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3402 panic("Couldn't register /dev/console driver\n");
3403 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3405 if (IS_ERR(consdev))
3408 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3411 vty_init(&console_fops);