2 * linux/drivers/char/tty_io.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
9 * or rs-channels. It also implements echoing, cooked mode etc.
11 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
13 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
14 * tty_struct and tty_queue structures. Previously there was an array
15 * of 256 tty_struct's which was statically allocated, and the
16 * tty_queue structures were allocated at boot time. Both are now
17 * dynamically allocated only when the tty is open.
19 * Also restructured routines so that there is more of a separation
20 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
21 * the low-level tty routines (serial.c, pty.c, console.c). This
22 * makes for cleaner and more compact code. -TYT, 9/17/92
24 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
25 * which can be dynamically activated and de-activated by the line
26 * discipline handling modules (like SLIP).
28 * NOTE: pay no attention to the line discipline code (yet); its
29 * interface is still subject to change in this version...
32 * Added functionality to the OPOST tty handling. No delays, but all
33 * other bits should be there.
34 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
36 * Rewrote canonical mode and added more termios flags.
37 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
39 * Reorganized FASYNC support so mouse code can share it.
40 * -- ctm@ardi.com, 9Sep95
42 * New TIOCLINUX variants added.
43 * -- mj@k332.feld.cvut.cz, 19-Nov-95
45 * Restrict vt switching via ioctl()
46 * -- grif@cs.ucr.edu, 5-Dec-95
48 * Move console and virtual terminal code to more appropriate files,
49 * implement CONFIG_VT and generalize console device interface.
50 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
52 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
53 * -- Bill Hawes <whawes@star.net>, June 97
55 * Added devfs support.
56 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
58 * Added support for a Unix98-style ptmx device.
59 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
61 * Reduced memory usage for older ARM systems
62 * -- Russell King <rmk@arm.linux.org.uk>
64 * Move do_SAK() into process context. Less stack use in devfs functions.
65 * alloc_tty_struct() always uses kmalloc()
66 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
69 #include <linux/types.h>
70 #include <linux/major.h>
71 #include <linux/errno.h>
72 #include <linux/signal.h>
73 #include <linux/fcntl.h>
74 #include <linux/sched.h>
75 #include <linux/interrupt.h>
76 #include <linux/tty.h>
77 #include <linux/tty_driver.h>
78 #include <linux/tty_flip.h>
79 #include <linux/devpts_fs.h>
80 #include <linux/file.h>
81 #include <linux/fdtable.h>
82 #include <linux/console.h>
83 #include <linux/timer.h>
84 #include <linux/ctype.h>
87 #include <linux/string.h>
88 #include <linux/slab.h>
89 #include <linux/poll.h>
90 #include <linux/proc_fs.h>
91 #include <linux/init.h>
92 #include <linux/module.h>
93 #include <linux/smp_lock.h>
94 #include <linux/device.h>
95 #include <linux/wait.h>
96 #include <linux/bitops.h>
97 #include <linux/delay.h>
98 #include <linux/seq_file.h>
100 #include <linux/uaccess.h>
101 #include <asm/system.h>
103 #include <linux/kbd_kern.h>
104 #include <linux/vt_kern.h>
105 #include <linux/selection.h>
107 #include <linux/kmod.h>
108 #include <linux/nsproxy.h>
110 #undef TTY_DEBUG_HANGUP
112 #define TTY_PARANOIA_CHECK 1
113 #define CHECK_TTY_COUNT 1
115 struct ktermios tty_std_termios
= { /* for the benefit of tty drivers */
116 .c_iflag
= ICRNL
| IXON
,
117 .c_oflag
= OPOST
| ONLCR
,
118 .c_cflag
= B38400
| CS8
| CREAD
| HUPCL
,
119 .c_lflag
= ISIG
| ICANON
| ECHO
| ECHOE
| ECHOK
|
120 ECHOCTL
| ECHOKE
| IEXTEN
,
126 EXPORT_SYMBOL(tty_std_termios
);
128 /* This list gets poked at by procfs and various bits of boot up code. This
129 could do with some rationalisation such as pulling the tty proc function
132 LIST_HEAD(tty_drivers
); /* linked list of tty drivers */
134 /* Mutex to protect creating and releasing a tty. This is shared with
135 vt.c for deeply disgusting hack reasons */
136 DEFINE_MUTEX(tty_mutex
);
137 EXPORT_SYMBOL(tty_mutex
);
139 /* Spinlock to protect the tty->tty_files list */
140 DEFINE_SPINLOCK(tty_files_lock
);
142 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
143 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
144 ssize_t
redirected_tty_write(struct file
*, const char __user
*,
146 static unsigned int tty_poll(struct file
*, poll_table
*);
147 static int tty_open(struct inode
*, struct file
*);
148 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
);
150 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
153 #define tty_compat_ioctl NULL
155 static int __tty_fasync(int fd
, struct file
*filp
, int on
);
156 static int tty_fasync(int fd
, struct file
*filp
, int on
);
157 static void release_tty(struct tty_struct
*tty
, int idx
);
158 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
159 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
162 * alloc_tty_struct - allocate a tty object
164 * Return a new empty tty structure. The data fields have not
165 * been initialized in any way but has been zeroed
170 struct tty_struct
*alloc_tty_struct(void)
172 return kzalloc(sizeof(struct tty_struct
), GFP_KERNEL
);
176 * free_tty_struct - free a disused tty
177 * @tty: tty struct to free
179 * Free the write buffers, tty queue and tty memory itself.
181 * Locking: none. Must be called after tty is definitely unused
184 void free_tty_struct(struct tty_struct
*tty
)
186 kfree(tty
->write_buf
);
187 tty_buffer_free_all(tty
);
191 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
194 * tty_name - return tty naming
195 * @tty: tty structure
196 * @buf: buffer for output
198 * Convert a tty structure into a name. The name reflects the kernel
199 * naming policy and if udev is in use may not reflect user space
204 char *tty_name(struct tty_struct
*tty
, char *buf
)
206 if (!tty
) /* Hmm. NULL pointer. That's fun. */
207 strcpy(buf
, "NULL tty");
209 strcpy(buf
, tty
->name
);
213 EXPORT_SYMBOL(tty_name
);
215 int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
218 #ifdef TTY_PARANOIA_CHECK
221 "null TTY for (%d:%d) in %s\n",
222 imajor(inode
), iminor(inode
), routine
);
225 if (tty
->magic
!= TTY_MAGIC
) {
227 "bad magic number for tty struct (%d:%d) in %s\n",
228 imajor(inode
), iminor(inode
), routine
);
235 static int check_tty_count(struct tty_struct
*tty
, const char *routine
)
237 #ifdef CHECK_TTY_COUNT
241 spin_lock(&tty_files_lock
);
242 list_for_each(p
, &tty
->tty_files
) {
245 spin_unlock(&tty_files_lock
);
246 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
247 tty
->driver
->subtype
== PTY_TYPE_SLAVE
&&
248 tty
->link
&& tty
->link
->count
)
250 if (tty
->count
!= count
) {
251 printk(KERN_WARNING
"Warning: dev (%s) tty->count(%d) "
252 "!= #fd's(%d) in %s\n",
253 tty
->name
, tty
->count
, count
, routine
);
261 * get_tty_driver - find device of a tty
262 * @dev_t: device identifier
263 * @index: returns the index of the tty
265 * This routine returns a tty driver structure, given a device number
266 * and also passes back the index number.
268 * Locking: caller must hold tty_mutex
271 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
273 struct tty_driver
*p
;
275 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
276 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
277 if (device
< base
|| device
>= base
+ p
->num
)
279 *index
= device
- base
;
280 return tty_driver_kref_get(p
);
285 #ifdef CONFIG_CONSOLE_POLL
288 * tty_find_polling_driver - find device of a polled tty
289 * @name: name string to match
290 * @line: pointer to resulting tty line nr
292 * This routine returns a tty driver structure, given a name
293 * and the condition that the tty driver is capable of polled
296 struct tty_driver
*tty_find_polling_driver(char *name
, int *line
)
298 struct tty_driver
*p
, *res
= NULL
;
303 for (str
= name
; *str
; str
++)
304 if ((*str
>= '0' && *str
<= '9') || *str
== ',')
310 tty_line
= simple_strtoul(str
, &str
, 10);
312 mutex_lock(&tty_mutex
);
313 /* Search through the tty devices to look for a match */
314 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
315 if (strncmp(name
, p
->name
, len
) != 0)
323 if (tty_line
>= 0 && tty_line
<= p
->num
&& p
->ops
&&
324 p
->ops
->poll_init
&& !p
->ops
->poll_init(p
, tty_line
, stp
)) {
325 res
= tty_driver_kref_get(p
);
330 mutex_unlock(&tty_mutex
);
334 EXPORT_SYMBOL_GPL(tty_find_polling_driver
);
338 * tty_check_change - check for POSIX terminal changes
341 * If we try to write to, or set the state of, a terminal and we're
342 * not in the foreground, send a SIGTTOU. If the signal is blocked or
343 * ignored, go ahead and perform the operation. (POSIX 7.2)
348 int tty_check_change(struct tty_struct
*tty
)
353 if (current
->signal
->tty
!= tty
)
356 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
359 printk(KERN_WARNING
"tty_check_change: tty->pgrp == NULL!\n");
362 if (task_pgrp(current
) == tty
->pgrp
)
364 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
365 if (is_ignored(SIGTTOU
))
367 if (is_current_pgrp_orphaned()) {
371 kill_pgrp(task_pgrp(current
), SIGTTOU
, 1);
372 set_thread_flag(TIF_SIGPENDING
);
377 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
381 EXPORT_SYMBOL(tty_check_change
);
383 static ssize_t
hung_up_tty_read(struct file
*file
, char __user
*buf
,
384 size_t count
, loff_t
*ppos
)
389 static ssize_t
hung_up_tty_write(struct file
*file
, const char __user
*buf
,
390 size_t count
, loff_t
*ppos
)
395 /* No kernel lock held - none needed ;) */
396 static unsigned int hung_up_tty_poll(struct file
*filp
, poll_table
*wait
)
398 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
401 static long hung_up_tty_ioctl(struct file
*file
, unsigned int cmd
,
404 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
407 static long hung_up_tty_compat_ioctl(struct file
*file
,
408 unsigned int cmd
, unsigned long arg
)
410 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
413 static const struct file_operations tty_fops
= {
418 .unlocked_ioctl
= tty_ioctl
,
419 .compat_ioctl
= tty_compat_ioctl
,
421 .release
= tty_release
,
422 .fasync
= tty_fasync
,
425 static const struct file_operations console_fops
= {
428 .write
= redirected_tty_write
,
430 .unlocked_ioctl
= tty_ioctl
,
431 .compat_ioctl
= tty_compat_ioctl
,
433 .release
= tty_release
,
434 .fasync
= tty_fasync
,
437 static const struct file_operations hung_up_tty_fops
= {
439 .read
= hung_up_tty_read
,
440 .write
= hung_up_tty_write
,
441 .poll
= hung_up_tty_poll
,
442 .unlocked_ioctl
= hung_up_tty_ioctl
,
443 .compat_ioctl
= hung_up_tty_compat_ioctl
,
444 .release
= tty_release
,
447 static DEFINE_SPINLOCK(redirect_lock
);
448 static struct file
*redirect
;
451 * tty_wakeup - request more data
454 * Internal and external helper for wakeups of tty. This function
455 * informs the line discipline if present that the driver is ready
456 * to receive more output data.
459 void tty_wakeup(struct tty_struct
*tty
)
461 struct tty_ldisc
*ld
;
463 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
464 ld
= tty_ldisc_ref(tty
);
466 if (ld
->ops
->write_wakeup
)
467 ld
->ops
->write_wakeup(tty
);
471 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
474 EXPORT_SYMBOL_GPL(tty_wakeup
);
477 * __tty_hangup - actual handler for hangup events
480 * This can be called by the "eventd" kernel thread. That is process
481 * synchronous but doesn't hold any locks, so we need to make sure we
482 * have the appropriate locks for what we're doing.
484 * The hangup event clears any pending redirections onto the hung up
485 * device. It ensures future writes will error and it does the needed
486 * line discipline hangup and signal delivery. The tty object itself
491 * redirect lock for undoing redirection
492 * file list lock for manipulating list of ttys
493 * tty_ldisc_lock from called functions
494 * termios_mutex resetting termios data
495 * tasklist_lock to walk task list for hangup event
496 * ->siglock to protect ->signal/->sighand
498 void __tty_hangup(struct tty_struct
*tty
)
500 struct file
*cons_filp
= NULL
;
501 struct file
*filp
, *f
= NULL
;
502 struct task_struct
*p
;
503 int closecount
= 0, n
;
511 spin_lock(&redirect_lock
);
512 if (redirect
&& redirect
->private_data
== tty
) {
516 spin_unlock(&redirect_lock
);
520 /* inuse_filps is protected by the single tty lock,
521 this really needs to change if we want to flush the
522 workqueue with the lock held */
523 check_tty_count(tty
, "tty_hangup");
525 spin_lock(&tty_files_lock
);
526 /* This breaks for file handles being sent over AF_UNIX sockets ? */
527 list_for_each_entry(filp
, &tty
->tty_files
, f_u
.fu_list
) {
528 if (filp
->f_op
->write
== redirected_tty_write
)
530 if (filp
->f_op
->write
!= tty_write
)
533 __tty_fasync(-1, filp
, 0); /* can't block */
534 filp
->f_op
= &hung_up_tty_fops
;
536 spin_unlock(&tty_files_lock
);
538 tty_ldisc_hangup(tty
);
540 read_lock(&tasklist_lock
);
542 do_each_pid_task(tty
->session
, PIDTYPE_SID
, p
) {
543 spin_lock_irq(&p
->sighand
->siglock
);
544 if (p
->signal
->tty
== tty
) {
545 p
->signal
->tty
= NULL
;
546 /* We defer the dereferences outside fo
550 if (!p
->signal
->leader
) {
551 spin_unlock_irq(&p
->sighand
->siglock
);
554 __group_send_sig_info(SIGHUP
, SEND_SIG_PRIV
, p
);
555 __group_send_sig_info(SIGCONT
, SEND_SIG_PRIV
, p
);
556 put_pid(p
->signal
->tty_old_pgrp
); /* A noop */
557 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
559 p
->signal
->tty_old_pgrp
= get_pid(tty
->pgrp
);
560 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
561 spin_unlock_irq(&p
->sighand
->siglock
);
562 } while_each_pid_task(tty
->session
, PIDTYPE_SID
, p
);
564 read_unlock(&tasklist_lock
);
566 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
567 clear_bit(TTY_THROTTLED
, &tty
->flags
);
568 clear_bit(TTY_PUSH
, &tty
->flags
);
569 clear_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
);
570 put_pid(tty
->session
);
574 tty
->ctrl_status
= 0;
575 set_bit(TTY_HUPPED
, &tty
->flags
);
576 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
578 /* Account for the p->signal references we killed */
583 * If one of the devices matches a console pointer, we
584 * cannot just call hangup() because that will cause
585 * tty->count and state->count to go out of sync.
586 * So we just call close() the right number of times.
590 for (n
= 0; n
< closecount
; n
++)
591 tty
->ops
->close(tty
, cons_filp
);
592 } else if (tty
->ops
->hangup
)
593 (tty
->ops
->hangup
)(tty
);
595 * We don't want to have driver/ldisc interactions beyond
596 * the ones we did here. The driver layer expects no
597 * calls after ->hangup() from the ldisc side. However we
598 * can't yet guarantee all that.
600 set_bit(TTY_HUPPED
, &tty
->flags
);
601 tty_ldisc_enable(tty
);
609 static void do_tty_hangup(struct work_struct
*work
)
611 struct tty_struct
*tty
=
612 container_of(work
, struct tty_struct
, hangup_work
);
618 * tty_hangup - trigger a hangup event
619 * @tty: tty to hangup
621 * A carrier loss (virtual or otherwise) has occurred on this like
622 * schedule a hangup sequence to run after this event.
625 void tty_hangup(struct tty_struct
*tty
)
627 #ifdef TTY_DEBUG_HANGUP
629 printk(KERN_DEBUG
"%s hangup...\n", tty_name(tty
, buf
));
631 schedule_work(&tty
->hangup_work
);
634 EXPORT_SYMBOL(tty_hangup
);
637 * tty_vhangup - process vhangup
638 * @tty: tty to hangup
640 * The user has asked via system call for the terminal to be hung up.
641 * We do this synchronously so that when the syscall returns the process
642 * is complete. That guarantee is necessary for security reasons.
645 void tty_vhangup(struct tty_struct
*tty
)
647 #ifdef TTY_DEBUG_HANGUP
650 printk(KERN_DEBUG
"%s vhangup...\n", tty_name(tty
, buf
));
655 EXPORT_SYMBOL(tty_vhangup
);
659 * tty_vhangup_self - process vhangup for own ctty
661 * Perform a vhangup on the current controlling tty
664 void tty_vhangup_self(void)
666 struct tty_struct
*tty
;
668 tty
= get_current_tty();
676 * tty_hung_up_p - was tty hung up
677 * @filp: file pointer of tty
679 * Return true if the tty has been subject to a vhangup or a carrier
683 int tty_hung_up_p(struct file
*filp
)
685 return (filp
->f_op
== &hung_up_tty_fops
);
688 EXPORT_SYMBOL(tty_hung_up_p
);
690 static void session_clear_tty(struct pid
*session
)
692 struct task_struct
*p
;
693 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
695 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
699 * disassociate_ctty - disconnect controlling tty
700 * @on_exit: true if exiting so need to "hang up" the session
702 * This function is typically called only by the session leader, when
703 * it wants to disassociate itself from its controlling tty.
705 * It performs the following functions:
706 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
707 * (2) Clears the tty from being controlling the session
708 * (3) Clears the controlling tty for all processes in the
711 * The argument on_exit is set to 1 if called when a process is
712 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
715 * BTM is taken for hysterical raisins, and held when
716 * called from no_tty().
717 * tty_mutex is taken to protect tty
718 * ->siglock is taken to protect ->signal/->sighand
719 * tasklist_lock is taken to walk process list for sessions
720 * ->siglock is taken to protect ->signal/->sighand
723 void disassociate_ctty(int on_exit
)
725 struct tty_struct
*tty
;
726 struct pid
*tty_pgrp
= NULL
;
728 if (!current
->signal
->leader
)
731 tty
= get_current_tty();
733 tty_pgrp
= get_pid(tty
->pgrp
);
735 if (tty
->driver
->type
!= TTY_DRIVER_TYPE_PTY
)
739 } else if (on_exit
) {
740 struct pid
*old_pgrp
;
741 spin_lock_irq(¤t
->sighand
->siglock
);
742 old_pgrp
= current
->signal
->tty_old_pgrp
;
743 current
->signal
->tty_old_pgrp
= NULL
;
744 spin_unlock_irq(¤t
->sighand
->siglock
);
746 kill_pgrp(old_pgrp
, SIGHUP
, on_exit
);
747 kill_pgrp(old_pgrp
, SIGCONT
, on_exit
);
753 kill_pgrp(tty_pgrp
, SIGHUP
, on_exit
);
755 kill_pgrp(tty_pgrp
, SIGCONT
, on_exit
);
759 spin_lock_irq(¤t
->sighand
->siglock
);
760 put_pid(current
->signal
->tty_old_pgrp
);
761 current
->signal
->tty_old_pgrp
= NULL
;
762 spin_unlock_irq(¤t
->sighand
->siglock
);
764 tty
= get_current_tty();
767 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
768 put_pid(tty
->session
);
772 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
775 #ifdef TTY_DEBUG_HANGUP
776 printk(KERN_DEBUG
"error attempted to write to tty [0x%p]"
781 /* Now clear signal->tty under the lock */
782 read_lock(&tasklist_lock
);
783 session_clear_tty(task_session(current
));
784 read_unlock(&tasklist_lock
);
789 * no_tty - Ensure the current process does not have a controlling tty
793 struct task_struct
*tsk
= current
;
795 disassociate_ctty(0);
802 * stop_tty - propagate flow control
805 * Perform flow control to the driver. For PTY/TTY pairs we
806 * must also propagate the TIOCKPKT status. May be called
807 * on an already stopped device and will not re-call the driver
810 * This functionality is used by both the line disciplines for
811 * halting incoming flow and by the driver. It may therefore be
812 * called from any context, may be under the tty atomic_write_lock
816 * Uses the tty control lock internally
819 void stop_tty(struct tty_struct
*tty
)
822 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
824 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
828 if (tty
->link
&& tty
->link
->packet
) {
829 tty
->ctrl_status
&= ~TIOCPKT_START
;
830 tty
->ctrl_status
|= TIOCPKT_STOP
;
831 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
833 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
835 (tty
->ops
->stop
)(tty
);
838 EXPORT_SYMBOL(stop_tty
);
841 * start_tty - propagate flow control
844 * Start a tty that has been stopped if at all possible. Perform
845 * any necessary wakeups and propagate the TIOCPKT status. If this
846 * is the tty was previous stopped and is being started then the
847 * driver start method is invoked and the line discipline woken.
853 void start_tty(struct tty_struct
*tty
)
856 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
857 if (!tty
->stopped
|| tty
->flow_stopped
) {
858 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
862 if (tty
->link
&& tty
->link
->packet
) {
863 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
864 tty
->ctrl_status
|= TIOCPKT_START
;
865 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
867 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
869 (tty
->ops
->start
)(tty
);
870 /* If we have a running line discipline it may need kicking */
874 EXPORT_SYMBOL(start_tty
);
877 * tty_read - read method for tty device files
878 * @file: pointer to tty file
880 * @count: size of user buffer
883 * Perform the read system call function on this terminal device. Checks
884 * for hung up devices before calling the line discipline method.
887 * Locks the line discipline internally while needed. Multiple
888 * read calls may be outstanding in parallel.
891 static ssize_t
tty_read(struct file
*file
, char __user
*buf
, size_t count
,
895 struct tty_struct
*tty
;
897 struct tty_ldisc
*ld
;
899 tty
= file
->private_data
;
900 inode
= file
->f_path
.dentry
->d_inode
;
901 if (tty_paranoia_check(tty
, inode
, "tty_read"))
903 if (!tty
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
906 /* We want to wait for the line discipline to sort out in this
908 ld
= tty_ldisc_ref_wait(tty
);
910 i
= (ld
->ops
->read
)(tty
, file
, buf
, count
);
915 inode
->i_atime
= current_fs_time(inode
->i_sb
);
919 void tty_write_unlock(struct tty_struct
*tty
)
921 mutex_unlock(&tty
->atomic_write_lock
);
922 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
925 int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
927 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
930 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
937 * Split writes up in sane blocksizes to avoid
938 * denial-of-service type attacks
940 static inline ssize_t
do_tty_write(
941 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
942 struct tty_struct
*tty
,
944 const char __user
*buf
,
947 ssize_t ret
, written
= 0;
950 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
955 * We chunk up writes into a temporary buffer. This
956 * simplifies low-level drivers immensely, since they
957 * don't have locking issues and user mode accesses.
959 * But if TTY_NO_WRITE_SPLIT is set, we should use a
962 * The default chunk-size is 2kB, because the NTTY
963 * layer has problems with bigger chunks. It will
964 * claim to be able to handle more characters than
967 * FIXME: This can probably go away now except that 64K chunks
968 * are too likely to fail unless switched to vmalloc...
971 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
976 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
977 if (tty
->write_cnt
< chunk
) {
978 unsigned char *buf_chunk
;
983 buf_chunk
= kmalloc(chunk
, GFP_KERNEL
);
988 kfree(tty
->write_buf
);
989 tty
->write_cnt
= chunk
;
990 tty
->write_buf
= buf_chunk
;
993 /* Do the write .. */
999 if (copy_from_user(tty
->write_buf
, buf
, size
))
1001 ret
= write(tty
, file
, tty
->write_buf
, size
);
1010 if (signal_pending(current
))
1015 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1016 inode
->i_mtime
= current_fs_time(inode
->i_sb
);
1020 tty_write_unlock(tty
);
1025 * tty_write_message - write a message to a certain tty, not just the console.
1026 * @tty: the destination tty_struct
1027 * @msg: the message to write
1029 * This is used for messages that need to be redirected to a specific tty.
1030 * We don't put it into the syslog queue right now maybe in the future if
1033 * We must still hold the BTM and test the CLOSING flag for the moment.
1036 void tty_write_message(struct tty_struct
*tty
, char *msg
)
1039 mutex_lock(&tty
->atomic_write_lock
);
1041 if (tty
->ops
->write
&& !test_bit(TTY_CLOSING
, &tty
->flags
)) {
1043 tty
->ops
->write(tty
, msg
, strlen(msg
));
1046 tty_write_unlock(tty
);
1053 * tty_write - write method for tty device file
1054 * @file: tty file pointer
1055 * @buf: user data to write
1056 * @count: bytes to write
1059 * Write data to a tty device via the line discipline.
1062 * Locks the line discipline as required
1063 * Writes to the tty driver are serialized by the atomic_write_lock
1064 * and are then processed in chunks to the device. The line discipline
1065 * write method will not be invoked in parallel for each device.
1068 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
1069 size_t count
, loff_t
*ppos
)
1071 struct tty_struct
*tty
;
1072 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1074 struct tty_ldisc
*ld
;
1076 tty
= file
->private_data
;
1077 if (tty_paranoia_check(tty
, inode
, "tty_write"))
1079 if (!tty
|| !tty
->ops
->write
||
1080 (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1082 /* Short term debug to catch buggy drivers */
1083 if (tty
->ops
->write_room
== NULL
)
1084 printk(KERN_ERR
"tty driver %s lacks a write_room method.\n",
1086 ld
= tty_ldisc_ref_wait(tty
);
1087 if (!ld
->ops
->write
)
1090 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
1091 tty_ldisc_deref(ld
);
1095 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
1096 size_t count
, loff_t
*ppos
)
1098 struct file
*p
= NULL
;
1100 spin_lock(&redirect_lock
);
1105 spin_unlock(&redirect_lock
);
1109 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1113 return tty_write(file
, buf
, count
, ppos
);
1116 static char ptychar
[] = "pqrstuvwxyzabcde";
1119 * pty_line_name - generate name for a pty
1120 * @driver: the tty driver in use
1121 * @index: the minor number
1122 * @p: output buffer of at least 6 bytes
1124 * Generate a name from a driver reference and write it to the output
1129 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1131 int i
= index
+ driver
->name_base
;
1132 /* ->name is initialized to "ttyp", but "tty" is expected */
1133 sprintf(p
, "%s%c%x",
1134 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1135 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1139 * tty_line_name - generate name for a tty
1140 * @driver: the tty driver in use
1141 * @index: the minor number
1142 * @p: output buffer of at least 7 bytes
1144 * Generate a name from a driver reference and write it to the output
1149 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1151 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
1155 * tty_driver_lookup_tty() - find an existing tty, if any
1156 * @driver: the driver for the tty
1157 * @idx: the minor number
1159 * Return the tty, if found or ERR_PTR() otherwise.
1161 * Locking: tty_mutex must be held. If tty is found, the mutex must
1162 * be held until the 'fast-open' is also done. Will change once we
1163 * have refcounting in the driver and per driver locking
1165 static struct tty_struct
*tty_driver_lookup_tty(struct tty_driver
*driver
,
1166 struct inode
*inode
, int idx
)
1168 struct tty_struct
*tty
;
1170 if (driver
->ops
->lookup
)
1171 return driver
->ops
->lookup(driver
, inode
, idx
);
1173 tty
= driver
->ttys
[idx
];
1178 * tty_init_termios - helper for termios setup
1179 * @tty: the tty to set up
1181 * Initialise the termios structures for this tty. Thus runs under
1182 * the tty_mutex currently so we can be relaxed about ordering.
1185 int tty_init_termios(struct tty_struct
*tty
)
1187 struct ktermios
*tp
;
1188 int idx
= tty
->index
;
1190 tp
= tty
->driver
->termios
[idx
];
1192 tp
= kzalloc(sizeof(struct ktermios
[2]), GFP_KERNEL
);
1195 memcpy(tp
, &tty
->driver
->init_termios
,
1196 sizeof(struct ktermios
));
1197 tty
->driver
->termios
[idx
] = tp
;
1200 tty
->termios_locked
= tp
+ 1;
1202 /* Compatibility until drivers always set this */
1203 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
1204 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
1207 EXPORT_SYMBOL_GPL(tty_init_termios
);
1210 * tty_driver_install_tty() - install a tty entry in the driver
1211 * @driver: the driver for the tty
1214 * Install a tty object into the driver tables. The tty->index field
1215 * will be set by the time this is called. This method is responsible
1216 * for ensuring any need additional structures are allocated and
1219 * Locking: tty_mutex for now
1221 static int tty_driver_install_tty(struct tty_driver
*driver
,
1222 struct tty_struct
*tty
)
1224 int idx
= tty
->index
;
1227 if (driver
->ops
->install
) {
1228 ret
= driver
->ops
->install(driver
, tty
);
1232 if (tty_init_termios(tty
) == 0) {
1233 tty_driver_kref_get(driver
);
1235 driver
->ttys
[idx
] = tty
;
1242 * tty_driver_remove_tty() - remove a tty from the driver tables
1243 * @driver: the driver for the tty
1244 * @idx: the minor number
1246 * Remvoe a tty object from the driver tables. The tty->index field
1247 * will be set by the time this is called.
1249 * Locking: tty_mutex for now
1251 static void tty_driver_remove_tty(struct tty_driver
*driver
,
1252 struct tty_struct
*tty
)
1254 if (driver
->ops
->remove
)
1255 driver
->ops
->remove(driver
, tty
);
1257 driver
->ttys
[tty
->index
] = NULL
;
1261 * tty_reopen() - fast re-open of an open tty
1262 * @tty - the tty to open
1264 * Return 0 on success, -errno on error.
1266 * Locking: tty_mutex must be held from the time the tty was found
1267 * till this open completes.
1269 static int tty_reopen(struct tty_struct
*tty
)
1271 struct tty_driver
*driver
= tty
->driver
;
1273 if (test_bit(TTY_CLOSING
, &tty
->flags
))
1276 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1277 driver
->subtype
== PTY_TYPE_MASTER
) {
1279 * special case for PTY masters: only one open permitted,
1280 * and the slave side open count is incremented as well.
1288 tty
->driver
= driver
; /* N.B. why do this every time?? */
1290 mutex_lock(&tty
->ldisc_mutex
);
1291 WARN_ON(!test_bit(TTY_LDISC
, &tty
->flags
));
1292 mutex_unlock(&tty
->ldisc_mutex
);
1298 * tty_init_dev - initialise a tty device
1299 * @driver: tty driver we are opening a device on
1300 * @idx: device index
1301 * @ret_tty: returned tty structure
1302 * @first_ok: ok to open a new device (used by ptmx)
1304 * Prepare a tty device. This may not be a "new" clean device but
1305 * could also be an active device. The pty drivers require special
1306 * handling because of this.
1309 * The function is called under the tty_mutex, which
1310 * protects us from the tty struct or driver itself going away.
1312 * On exit the tty device has the line discipline attached and
1313 * a reference count of 1. If a pair was created for pty/tty use
1314 * and the other was a pty master then it too has a reference count of 1.
1316 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1317 * failed open. The new code protects the open with a mutex, so it's
1318 * really quite straightforward. The mutex locking can probably be
1319 * relaxed for the (most common) case of reopening a tty.
1322 struct tty_struct
*tty_init_dev(struct tty_driver
*driver
, int idx
,
1325 struct tty_struct
*tty
;
1328 /* Check if pty master is being opened multiple times */
1329 if (driver
->subtype
== PTY_TYPE_MASTER
&&
1330 (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && !first_ok
) {
1331 return ERR_PTR(-EIO
);
1335 * First time open is complex, especially for PTY devices.
1336 * This code guarantees that either everything succeeds and the
1337 * TTY is ready for operation, or else the table slots are vacated
1338 * and the allocated memory released. (Except that the termios
1339 * and locked termios may be retained.)
1342 if (!try_module_get(driver
->owner
))
1343 return ERR_PTR(-ENODEV
);
1345 tty
= alloc_tty_struct();
1348 initialize_tty_struct(tty
, driver
, idx
);
1350 retval
= tty_driver_install_tty(driver
, tty
);
1352 free_tty_struct(tty
);
1353 module_put(driver
->owner
);
1354 return ERR_PTR(retval
);
1358 * Structures all installed ... call the ldisc open routines.
1359 * If we fail here just call release_tty to clean up. No need
1360 * to decrement the use counts, as release_tty doesn't care.
1362 retval
= tty_ldisc_setup(tty
, tty
->link
);
1364 goto release_mem_out
;
1368 module_put(driver
->owner
);
1369 return ERR_PTR(-ENOMEM
);
1371 /* call the tty release_tty routine to clean out this slot */
1373 if (printk_ratelimit())
1374 printk(KERN_INFO
"tty_init_dev: ldisc open failed, "
1375 "clearing slot %d\n", idx
);
1376 release_tty(tty
, idx
);
1377 return ERR_PTR(retval
);
1380 void tty_free_termios(struct tty_struct
*tty
)
1382 struct ktermios
*tp
;
1383 int idx
= tty
->index
;
1384 /* Kill this flag and push into drivers for locking etc */
1385 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
) {
1386 /* FIXME: Locking on ->termios array */
1388 tty
->driver
->termios
[idx
] = NULL
;
1392 EXPORT_SYMBOL(tty_free_termios
);
1394 void tty_shutdown(struct tty_struct
*tty
)
1396 tty_driver_remove_tty(tty
->driver
, tty
);
1397 tty_free_termios(tty
);
1399 EXPORT_SYMBOL(tty_shutdown
);
1402 * release_one_tty - release tty structure memory
1403 * @kref: kref of tty we are obliterating
1405 * Releases memory associated with a tty structure, and clears out the
1406 * driver table slots. This function is called when a device is no longer
1407 * in use. It also gets called when setup of a device fails.
1410 * tty_mutex - sometimes only
1411 * takes the file list lock internally when working on the list
1412 * of ttys that the driver keeps.
1414 * This method gets called from a work queue so that the driver private
1415 * cleanup ops can sleep (needed for USB at least)
1417 static void release_one_tty(struct work_struct
*work
)
1419 struct tty_struct
*tty
=
1420 container_of(work
, struct tty_struct
, hangup_work
);
1421 struct tty_driver
*driver
= tty
->driver
;
1423 if (tty
->ops
->cleanup
)
1424 tty
->ops
->cleanup(tty
);
1427 tty_driver_kref_put(driver
);
1428 module_put(driver
->owner
);
1430 spin_lock(&tty_files_lock
);
1431 list_del_init(&tty
->tty_files
);
1432 spin_unlock(&tty_files_lock
);
1435 put_pid(tty
->session
);
1436 free_tty_struct(tty
);
1439 static void queue_release_one_tty(struct kref
*kref
)
1441 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1443 if (tty
->ops
->shutdown
)
1444 tty
->ops
->shutdown(tty
);
1448 /* The hangup queue is now free so we can reuse it rather than
1449 waste a chunk of memory for each port */
1450 INIT_WORK(&tty
->hangup_work
, release_one_tty
);
1451 schedule_work(&tty
->hangup_work
);
1455 * tty_kref_put - release a tty kref
1458 * Release a reference to a tty device and if need be let the kref
1459 * layer destruct the object for us
1462 void tty_kref_put(struct tty_struct
*tty
)
1465 kref_put(&tty
->kref
, queue_release_one_tty
);
1467 EXPORT_SYMBOL(tty_kref_put
);
1470 * release_tty - release tty structure memory
1472 * Release both @tty and a possible linked partner (think pty pair),
1473 * and decrement the refcount of the backing module.
1476 * tty_mutex - sometimes only
1477 * takes the file list lock internally when working on the list
1478 * of ttys that the driver keeps.
1479 * FIXME: should we require tty_mutex is held here ??
1482 static void release_tty(struct tty_struct
*tty
, int idx
)
1484 /* This should always be true but check for the moment */
1485 WARN_ON(tty
->index
!= idx
);
1488 tty_kref_put(tty
->link
);
1493 * tty_release - vfs callback for close
1494 * @inode: inode of tty
1495 * @filp: file pointer for handle to tty
1497 * Called the last time each file handle is closed that references
1498 * this tty. There may however be several such references.
1501 * Takes bkl. See tty_release_dev
1503 * Even releasing the tty structures is a tricky business.. We have
1504 * to be very careful that the structures are all released at the
1505 * same time, as interrupts might otherwise get the wrong pointers.
1507 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1508 * lead to double frees or releasing memory still in use.
1511 int tty_release(struct inode
*inode
, struct file
*filp
)
1513 struct tty_struct
*tty
, *o_tty
;
1514 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
1519 tty
= filp
->private_data
;
1520 if (tty_paranoia_check(tty
, inode
, "tty_release_dev"))
1524 check_tty_count(tty
, "tty_release_dev");
1526 __tty_fasync(-1, filp
, 0);
1529 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1530 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
1531 devpts
= (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) != 0;
1534 #ifdef TTY_PARANOIA_CHECK
1535 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1536 printk(KERN_DEBUG
"tty_release_dev: bad idx when trying to "
1537 "free (%s)\n", tty
->name
);
1542 if (tty
!= tty
->driver
->ttys
[idx
]) {
1544 printk(KERN_DEBUG
"tty_release_dev: driver.table[%d] not tty "
1545 "for (%s)\n", idx
, tty
->name
);
1548 if (tty
->termios
!= tty
->driver
->termios
[idx
]) {
1550 printk(KERN_DEBUG
"tty_release_dev: driver.termios[%d] not termios "
1558 #ifdef TTY_DEBUG_HANGUP
1559 printk(KERN_DEBUG
"tty_release_dev of %s (tty count=%d)...",
1560 tty_name(tty
, buf
), tty
->count
);
1563 #ifdef TTY_PARANOIA_CHECK
1564 if (tty
->driver
->other
&&
1565 !(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
1566 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1568 printk(KERN_DEBUG
"tty_release_dev: other->table[%d] "
1569 "not o_tty for (%s)\n",
1573 if (o_tty
->termios
!= tty
->driver
->other
->termios
[idx
]) {
1575 printk(KERN_DEBUG
"tty_release_dev: other->termios[%d] "
1576 "not o_termios for (%s)\n",
1580 if (o_tty
->link
!= tty
) {
1582 printk(KERN_DEBUG
"tty_release_dev: bad pty pointers\n");
1587 if (tty
->ops
->close
)
1588 tty
->ops
->close(tty
, filp
);
1592 * Sanity check: if tty->count is going to zero, there shouldn't be
1593 * any waiters on tty->read_wait or tty->write_wait. We test the
1594 * wait queues and kick everyone out _before_ actually starting to
1595 * close. This ensures that we won't block while releasing the tty
1598 * The test for the o_tty closing is necessary, since the master and
1599 * slave sides may close in any order. If the slave side closes out
1600 * first, its count will be one, since the master side holds an open.
1601 * Thus this test wouldn't be triggered at the time the slave closes,
1604 * Note that it's possible for the tty to be opened again while we're
1605 * flushing out waiters. By recalculating the closing flags before
1606 * each iteration we avoid any problems.
1609 /* Guard against races with tty->count changes elsewhere and
1610 opens on /dev/tty */
1612 mutex_lock(&tty_mutex
);
1614 tty_closing
= tty
->count
<= 1;
1615 o_tty_closing
= o_tty
&&
1616 (o_tty
->count
<= (pty_master
? 1 : 0));
1620 if (waitqueue_active(&tty
->read_wait
)) {
1621 wake_up_poll(&tty
->read_wait
, POLLIN
);
1624 if (waitqueue_active(&tty
->write_wait
)) {
1625 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1629 if (o_tty_closing
) {
1630 if (waitqueue_active(&o_tty
->read_wait
)) {
1631 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1634 if (waitqueue_active(&o_tty
->write_wait
)) {
1635 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1642 printk(KERN_WARNING
"tty_release_dev: %s: read/write wait queue "
1643 "active!\n", tty_name(tty
, buf
));
1645 mutex_unlock(&tty_mutex
);
1650 * The closing flags are now consistent with the open counts on
1651 * both sides, and we've completed the last operation that could
1652 * block, so it's safe to proceed with closing.
1655 if (--o_tty
->count
< 0) {
1656 printk(KERN_WARNING
"tty_release_dev: bad pty slave count "
1658 o_tty
->count
, tty_name(o_tty
, buf
));
1662 if (--tty
->count
< 0) {
1663 printk(KERN_WARNING
"tty_release_dev: bad tty->count (%d) for %s\n",
1664 tty
->count
, tty_name(tty
, buf
));
1669 * We've decremented tty->count, so we need to remove this file
1670 * descriptor off the tty->tty_files list; this serves two
1672 * - check_tty_count sees the correct number of file descriptors
1673 * associated with this tty.
1674 * - do_tty_hangup no longer sees this file descriptor as
1675 * something that needs to be handled for hangups.
1677 spin_lock(&tty_files_lock
);
1678 BUG_ON(list_empty(&filp
->f_u
.fu_list
));
1679 list_del_init(&filp
->f_u
.fu_list
);
1680 spin_unlock(&tty_files_lock
);
1681 filp
->private_data
= NULL
;
1684 * Perform some housekeeping before deciding whether to return.
1686 * Set the TTY_CLOSING flag if this was the last open. In the
1687 * case of a pty we may have to wait around for the other side
1688 * to close, and TTY_CLOSING makes sure we can't be reopened.
1691 set_bit(TTY_CLOSING
, &tty
->flags
);
1693 set_bit(TTY_CLOSING
, &o_tty
->flags
);
1696 * If _either_ side is closing, make sure there aren't any
1697 * processes that still think tty or o_tty is their controlling
1700 if (tty_closing
|| o_tty_closing
) {
1701 read_lock(&tasklist_lock
);
1702 session_clear_tty(tty
->session
);
1704 session_clear_tty(o_tty
->session
);
1705 read_unlock(&tasklist_lock
);
1708 mutex_unlock(&tty_mutex
);
1710 /* check whether both sides are closing ... */
1711 if (!tty_closing
|| (o_tty
&& !o_tty_closing
)) {
1716 #ifdef TTY_DEBUG_HANGUP
1717 printk(KERN_DEBUG
"freeing tty structure...");
1720 * Ask the line discipline code to release its structures
1722 tty_ldisc_release(tty
, o_tty
);
1724 * The release_tty function takes care of the details of clearing
1725 * the slots and preserving the termios structure.
1727 release_tty(tty
, idx
);
1729 /* Make this pty number available for reallocation */
1731 devpts_kill_index(inode
, idx
);
1737 * tty_open - open a tty device
1738 * @inode: inode of device file
1739 * @filp: file pointer to tty
1741 * tty_open and tty_release keep up the tty count that contains the
1742 * number of opens done on a tty. We cannot use the inode-count, as
1743 * different inodes might point to the same tty.
1745 * Open-counting is needed for pty masters, as well as for keeping
1746 * track of serial lines: DTR is dropped when the last close happens.
1747 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1749 * The termios state of a pty is reset on first open so that
1750 * settings don't persist across reuse.
1752 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1753 * tty->count should protect the rest.
1754 * ->siglock protects ->signal/->sighand
1757 static int tty_open(struct inode
*inode
, struct file
*filp
)
1759 struct tty_struct
*tty
= NULL
;
1761 struct tty_driver
*driver
;
1763 dev_t device
= inode
->i_rdev
;
1764 unsigned saved_flags
= filp
->f_flags
;
1766 nonseekable_open(inode
, filp
);
1769 noctty
= filp
->f_flags
& O_NOCTTY
;
1773 mutex_lock(&tty_mutex
);
1776 if (device
== MKDEV(TTYAUX_MAJOR
, 0)) {
1777 tty
= get_current_tty();
1780 mutex_unlock(&tty_mutex
);
1783 driver
= tty_driver_kref_get(tty
->driver
);
1785 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1787 /* FIXME: Should we take a driver reference ? */
1792 if (device
== MKDEV(TTY_MAJOR
, 0)) {
1793 extern struct tty_driver
*console_driver
;
1794 driver
= tty_driver_kref_get(console_driver
);
1800 if (device
== MKDEV(TTYAUX_MAJOR
, 1)) {
1801 struct tty_driver
*console_driver
= console_device(&index
);
1802 if (console_driver
) {
1803 driver
= tty_driver_kref_get(console_driver
);
1805 /* Don't let /dev/console block */
1806 filp
->f_flags
|= O_NONBLOCK
;
1812 mutex_unlock(&tty_mutex
);
1816 driver
= get_tty_driver(device
, &index
);
1819 mutex_unlock(&tty_mutex
);
1824 /* check whether we're reopening an existing tty */
1825 tty
= tty_driver_lookup_tty(driver
, inode
, index
);
1829 mutex_unlock(&tty_mutex
);
1830 return PTR_ERR(tty
);
1835 retval
= tty_reopen(tty
);
1837 tty
= ERR_PTR(retval
);
1839 tty
= tty_init_dev(driver
, index
, 0);
1841 mutex_unlock(&tty_mutex
);
1842 tty_driver_kref_put(driver
);
1845 return PTR_ERR(tty
);
1848 filp
->private_data
= tty
;
1849 BUG_ON(list_empty(&filp
->f_u
.fu_list
));
1850 file_sb_list_del(filp
); /* __dentry_open has put it on the sb list */
1851 spin_lock(&tty_files_lock
);
1852 list_add(&filp
->f_u
.fu_list
, &tty
->tty_files
);
1853 spin_unlock(&tty_files_lock
);
1854 check_tty_count(tty
, "tty_open");
1855 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1856 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1858 #ifdef TTY_DEBUG_HANGUP
1859 printk(KERN_DEBUG
"opening %s...", tty
->name
);
1863 retval
= tty
->ops
->open(tty
, filp
);
1867 filp
->f_flags
= saved_flags
;
1869 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) &&
1870 !capable(CAP_SYS_ADMIN
))
1874 #ifdef TTY_DEBUG_HANGUP
1875 printk(KERN_DEBUG
"error %d in opening %s...", retval
,
1878 tty_unlock(); /* need to call tty_release without BTM */
1879 tty_release(inode
, filp
);
1880 if (retval
!= -ERESTARTSYS
)
1883 if (signal_pending(current
))
1888 * Need to reset f_op in case a hangup happened.
1891 if (filp
->f_op
== &hung_up_tty_fops
)
1892 filp
->f_op
= &tty_fops
;
1899 mutex_lock(&tty_mutex
);
1901 spin_lock_irq(¤t
->sighand
->siglock
);
1903 current
->signal
->leader
&&
1904 !current
->signal
->tty
&&
1905 tty
->session
== NULL
)
1906 __proc_set_tty(current
, tty
);
1907 spin_unlock_irq(¤t
->sighand
->siglock
);
1909 mutex_unlock(&tty_mutex
);
1916 * tty_poll - check tty status
1917 * @filp: file being polled
1918 * @wait: poll wait structures to update
1920 * Call the line discipline polling method to obtain the poll
1921 * status of the device.
1923 * Locking: locks called line discipline but ldisc poll method
1924 * may be re-entered freely by other callers.
1927 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
1929 struct tty_struct
*tty
;
1930 struct tty_ldisc
*ld
;
1933 tty
= filp
->private_data
;
1934 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
1937 ld
= tty_ldisc_ref_wait(tty
);
1939 ret
= (ld
->ops
->poll
)(tty
, filp
, wait
);
1940 tty_ldisc_deref(ld
);
1944 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
1946 struct tty_struct
*tty
;
1947 unsigned long flags
;
1950 tty
= filp
->private_data
;
1951 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
1954 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
1961 if (!waitqueue_active(&tty
->read_wait
))
1962 tty
->minimum_to_wake
= 1;
1963 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
1966 type
= PIDTYPE_PGID
;
1968 pid
= task_pid(current
);
1972 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1973 retval
= __f_setown(filp
, pid
, type
, 0);
1978 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
1979 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
1986 static int tty_fasync(int fd
, struct file
*filp
, int on
)
1990 retval
= __tty_fasync(fd
, filp
, on
);
1996 * tiocsti - fake input character
1997 * @tty: tty to fake input into
1998 * @p: pointer to character
2000 * Fake input to a tty device. Does the necessary locking and
2003 * FIXME: does not honour flow control ??
2006 * Called functions take tty_ldisc_lock
2007 * current->signal->tty check is safe without locks
2009 * FIXME: may race normal receive processing
2012 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2015 struct tty_ldisc
*ld
;
2017 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2019 if (get_user(ch
, p
))
2021 tty_audit_tiocsti(tty
, ch
);
2022 ld
= tty_ldisc_ref_wait(tty
);
2023 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2024 tty_ldisc_deref(ld
);
2029 * tiocgwinsz - implement window query ioctl
2031 * @arg: user buffer for result
2033 * Copies the kernel idea of the window size into the user buffer.
2035 * Locking: tty->termios_mutex is taken to ensure the winsize data
2039 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2043 mutex_lock(&tty
->termios_mutex
);
2044 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2045 mutex_unlock(&tty
->termios_mutex
);
2047 return err
? -EFAULT
: 0;
2051 * tty_do_resize - resize event
2052 * @tty: tty being resized
2053 * @rows: rows (character)
2054 * @cols: cols (character)
2056 * Update the termios variables and send the necessary signals to
2057 * peform a terminal resize correctly
2060 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2063 unsigned long flags
;
2066 mutex_lock(&tty
->termios_mutex
);
2067 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2069 /* Get the PID values and reference them so we can
2070 avoid holding the tty ctrl lock while sending signals */
2071 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2072 pgrp
= get_pid(tty
->pgrp
);
2073 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2076 kill_pgrp(pgrp
, SIGWINCH
, 1);
2081 mutex_unlock(&tty
->termios_mutex
);
2086 * tiocswinsz - implement window size set ioctl
2087 * @tty; tty side of tty
2088 * @arg: user buffer for result
2090 * Copies the user idea of the window size to the kernel. Traditionally
2091 * this is just advisory information but for the Linux console it
2092 * actually has driver level meaning and triggers a VC resize.
2095 * Driver dependant. The default do_resize method takes the
2096 * tty termios mutex and ctrl_lock. The console takes its own lock
2097 * then calls into the default method.
2100 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2102 struct winsize tmp_ws
;
2103 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2106 if (tty
->ops
->resize
)
2107 return tty
->ops
->resize(tty
, &tmp_ws
);
2109 return tty_do_resize(tty
, &tmp_ws
);
2113 * tioccons - allow admin to move logical console
2114 * @file: the file to become console
2116 * Allow the adminstrator to move the redirected console device
2118 * Locking: uses redirect_lock to guard the redirect information
2121 static int tioccons(struct file
*file
)
2123 if (!capable(CAP_SYS_ADMIN
))
2125 if (file
->f_op
->write
== redirected_tty_write
) {
2127 spin_lock(&redirect_lock
);
2130 spin_unlock(&redirect_lock
);
2135 spin_lock(&redirect_lock
);
2137 spin_unlock(&redirect_lock
);
2142 spin_unlock(&redirect_lock
);
2147 * fionbio - non blocking ioctl
2148 * @file: file to set blocking value
2149 * @p: user parameter
2151 * Historical tty interfaces had a blocking control ioctl before
2152 * the generic functionality existed. This piece of history is preserved
2153 * in the expected tty API of posix OS's.
2155 * Locking: none, the open file handle ensures it won't go away.
2158 static int fionbio(struct file
*file
, int __user
*p
)
2162 if (get_user(nonblock
, p
))
2165 spin_lock(&file
->f_lock
);
2167 file
->f_flags
|= O_NONBLOCK
;
2169 file
->f_flags
&= ~O_NONBLOCK
;
2170 spin_unlock(&file
->f_lock
);
2175 * tiocsctty - set controlling tty
2176 * @tty: tty structure
2177 * @arg: user argument
2179 * This ioctl is used to manage job control. It permits a session
2180 * leader to set this tty as the controlling tty for the session.
2183 * Takes tty_mutex() to protect tty instance
2184 * Takes tasklist_lock internally to walk sessions
2185 * Takes ->siglock() when updating signal->tty
2188 static int tiocsctty(struct tty_struct
*tty
, int arg
)
2191 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
2194 mutex_lock(&tty_mutex
);
2196 * The process must be a session leader and
2197 * not have a controlling tty already.
2199 if (!current
->signal
->leader
|| current
->signal
->tty
) {
2206 * This tty is already the controlling
2207 * tty for another session group!
2209 if (arg
== 1 && capable(CAP_SYS_ADMIN
)) {
2213 read_lock(&tasklist_lock
);
2214 session_clear_tty(tty
->session
);
2215 read_unlock(&tasklist_lock
);
2221 proc_set_tty(current
, tty
);
2223 mutex_unlock(&tty_mutex
);
2228 * tty_get_pgrp - return a ref counted pgrp pid
2231 * Returns a refcounted instance of the pid struct for the process
2232 * group controlling the tty.
2235 struct pid
*tty_get_pgrp(struct tty_struct
*tty
)
2237 unsigned long flags
;
2240 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2241 pgrp
= get_pid(tty
->pgrp
);
2242 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2246 EXPORT_SYMBOL_GPL(tty_get_pgrp
);
2249 * tiocgpgrp - get process group
2250 * @tty: tty passed by user
2251 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2254 * Obtain the process group of the tty. If there is no process group
2257 * Locking: none. Reference to current->signal->tty is safe.
2260 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2265 * (tty == real_tty) is a cheap way of
2266 * testing if the tty is NOT a master pty.
2268 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2270 pid
= tty_get_pgrp(real_tty
);
2271 ret
= put_user(pid_vnr(pid
), p
);
2277 * tiocspgrp - attempt to set process group
2278 * @tty: tty passed by user
2279 * @real_tty: tty side device matching tty passed by user
2282 * Set the process group of the tty to the session passed. Only
2283 * permitted where the tty session is our session.
2285 * Locking: RCU, ctrl lock
2288 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2292 int retval
= tty_check_change(real_tty
);
2293 unsigned long flags
;
2299 if (!current
->signal
->tty
||
2300 (current
->signal
->tty
!= real_tty
) ||
2301 (real_tty
->session
!= task_session(current
)))
2303 if (get_user(pgrp_nr
, p
))
2308 pgrp
= find_vpid(pgrp_nr
);
2313 if (session_of_pgrp(pgrp
) != task_session(current
))
2316 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2317 put_pid(real_tty
->pgrp
);
2318 real_tty
->pgrp
= get_pid(pgrp
);
2319 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2326 * tiocgsid - get session id
2327 * @tty: tty passed by user
2328 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2329 * @p: pointer to returned session id
2331 * Obtain the session id of the tty. If there is no session
2334 * Locking: none. Reference to current->signal->tty is safe.
2337 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2340 * (tty == real_tty) is a cheap way of
2341 * testing if the tty is NOT a master pty.
2343 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2345 if (!real_tty
->session
)
2347 return put_user(pid_vnr(real_tty
->session
), p
);
2351 * tiocsetd - set line discipline
2353 * @p: pointer to user data
2355 * Set the line discipline according to user request.
2357 * Locking: see tty_set_ldisc, this function is just a helper
2360 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2365 if (get_user(ldisc
, p
))
2368 ret
= tty_set_ldisc(tty
, ldisc
);
2374 * send_break - performed time break
2375 * @tty: device to break on
2376 * @duration: timeout in mS
2378 * Perform a timed break on hardware that lacks its own driver level
2379 * timed break functionality.
2382 * atomic_write_lock serializes
2386 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2390 if (tty
->ops
->break_ctl
== NULL
)
2393 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2394 retval
= tty
->ops
->break_ctl(tty
, duration
);
2396 /* Do the work ourselves */
2397 if (tty_write_lock(tty
, 0) < 0)
2399 retval
= tty
->ops
->break_ctl(tty
, -1);
2402 if (!signal_pending(current
))
2403 msleep_interruptible(duration
);
2404 retval
= tty
->ops
->break_ctl(tty
, 0);
2406 tty_write_unlock(tty
);
2407 if (signal_pending(current
))
2414 * tty_tiocmget - get modem status
2416 * @file: user file pointer
2417 * @p: pointer to result
2419 * Obtain the modem status bits from the tty driver if the feature
2420 * is supported. Return -EINVAL if it is not available.
2422 * Locking: none (up to the driver)
2425 static int tty_tiocmget(struct tty_struct
*tty
, struct file
*file
, int __user
*p
)
2427 int retval
= -EINVAL
;
2429 if (tty
->ops
->tiocmget
) {
2430 retval
= tty
->ops
->tiocmget(tty
, file
);
2433 retval
= put_user(retval
, p
);
2439 * tty_tiocmset - set modem status
2441 * @file: user file pointer
2442 * @cmd: command - clear bits, set bits or set all
2443 * @p: pointer to desired bits
2445 * Set the modem status bits from the tty driver if the feature
2446 * is supported. Return -EINVAL if it is not available.
2448 * Locking: none (up to the driver)
2451 static int tty_tiocmset(struct tty_struct
*tty
, struct file
*file
, unsigned int cmd
,
2455 unsigned int set
, clear
, val
;
2457 if (tty
->ops
->tiocmset
== NULL
)
2460 retval
= get_user(val
, p
);
2476 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2477 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2478 return tty
->ops
->tiocmset(tty
, file
, set
, clear
);
2481 struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2483 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2484 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2488 EXPORT_SYMBOL(tty_pair_get_tty
);
2490 struct tty_struct
*tty_pair_get_pty(struct tty_struct
*tty
)
2492 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2493 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2497 EXPORT_SYMBOL(tty_pair_get_pty
);
2500 * Split this up, as gcc can choke on it otherwise..
2502 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2504 struct tty_struct
*tty
, *real_tty
;
2505 void __user
*p
= (void __user
*)arg
;
2507 struct tty_ldisc
*ld
;
2508 struct inode
*inode
= file
->f_dentry
->d_inode
;
2510 tty
= file
->private_data
;
2511 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2514 real_tty
= tty_pair_get_tty(tty
);
2517 * Factor out some common prep work
2525 retval
= tty_check_change(tty
);
2528 if (cmd
!= TIOCCBRK
) {
2529 tty_wait_until_sent(tty
, 0);
2530 if (signal_pending(current
))
2541 return tiocsti(tty
, p
);
2543 return tiocgwinsz(real_tty
, p
);
2545 return tiocswinsz(real_tty
, p
);
2547 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2549 return fionbio(file
, p
);
2551 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2554 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2557 if (current
->signal
->tty
!= tty
)
2562 return tiocsctty(tty
, arg
);
2564 return tiocgpgrp(tty
, real_tty
, p
);
2566 return tiocspgrp(tty
, real_tty
, p
);
2568 return tiocgsid(tty
, real_tty
, p
);
2570 return put_user(tty
->ldisc
->ops
->num
, (int __user
*)p
);
2572 return tiocsetd(tty
, p
);
2576 case TIOCSBRK
: /* Turn break on, unconditionally */
2577 if (tty
->ops
->break_ctl
)
2578 return tty
->ops
->break_ctl(tty
, -1);
2580 case TIOCCBRK
: /* Turn break off, unconditionally */
2581 if (tty
->ops
->break_ctl
)
2582 return tty
->ops
->break_ctl(tty
, 0);
2584 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2585 /* non-zero arg means wait for all output data
2586 * to be sent (performed above) but don't send break.
2587 * This is used by the tcdrain() termios function.
2590 return send_break(tty
, 250);
2592 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2593 return send_break(tty
, arg
? arg
*100 : 250);
2596 return tty_tiocmget(tty
, file
, p
);
2600 return tty_tiocmset(tty
, file
, cmd
, p
);
2605 /* flush tty buffer and allow ldisc to process ioctl */
2606 tty_buffer_flush(tty
);
2611 if (tty
->ops
->ioctl
) {
2612 retval
= (tty
->ops
->ioctl
)(tty
, file
, cmd
, arg
);
2613 if (retval
!= -ENOIOCTLCMD
)
2616 ld
= tty_ldisc_ref_wait(tty
);
2618 if (ld
->ops
->ioctl
) {
2619 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2620 if (retval
== -ENOIOCTLCMD
)
2623 tty_ldisc_deref(ld
);
2627 #ifdef CONFIG_COMPAT
2628 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2631 struct inode
*inode
= file
->f_dentry
->d_inode
;
2632 struct tty_struct
*tty
= file
->private_data
;
2633 struct tty_ldisc
*ld
;
2634 int retval
= -ENOIOCTLCMD
;
2636 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2639 if (tty
->ops
->compat_ioctl
) {
2640 retval
= (tty
->ops
->compat_ioctl
)(tty
, file
, cmd
, arg
);
2641 if (retval
!= -ENOIOCTLCMD
)
2645 ld
= tty_ldisc_ref_wait(tty
);
2646 if (ld
->ops
->compat_ioctl
)
2647 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2648 tty_ldisc_deref(ld
);
2655 * This implements the "Secure Attention Key" --- the idea is to
2656 * prevent trojan horses by killing all processes associated with this
2657 * tty when the user hits the "Secure Attention Key". Required for
2658 * super-paranoid applications --- see the Orange Book for more details.
2660 * This code could be nicer; ideally it should send a HUP, wait a few
2661 * seconds, then send a INT, and then a KILL signal. But you then
2662 * have to coordinate with the init process, since all processes associated
2663 * with the current tty must be dead before the new getty is allowed
2666 * Now, if it would be correct ;-/ The current code has a nasty hole -
2667 * it doesn't catch files in flight. We may send the descriptor to ourselves
2668 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2670 * Nasty bug: do_SAK is being called in interrupt context. This can
2671 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2673 void __do_SAK(struct tty_struct
*tty
)
2678 struct task_struct
*g
, *p
;
2679 struct pid
*session
;
2682 struct fdtable
*fdt
;
2686 session
= tty
->session
;
2688 tty_ldisc_flush(tty
);
2690 tty_driver_flush_buffer(tty
);
2692 read_lock(&tasklist_lock
);
2693 /* Kill the entire session */
2694 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2695 printk(KERN_NOTICE
"SAK: killed process %d"
2696 " (%s): task_session(p)==tty->session\n",
2697 task_pid_nr(p
), p
->comm
);
2698 send_sig(SIGKILL
, p
, 1);
2699 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2700 /* Now kill any processes that happen to have the
2703 do_each_thread(g
, p
) {
2704 if (p
->signal
->tty
== tty
) {
2705 printk(KERN_NOTICE
"SAK: killed process %d"
2706 " (%s): task_session(p)==tty->session\n",
2707 task_pid_nr(p
), p
->comm
);
2708 send_sig(SIGKILL
, p
, 1);
2714 * We don't take a ref to the file, so we must
2715 * hold ->file_lock instead.
2717 spin_lock(&p
->files
->file_lock
);
2718 fdt
= files_fdtable(p
->files
);
2719 for (i
= 0; i
< fdt
->max_fds
; i
++) {
2720 filp
= fcheck_files(p
->files
, i
);
2723 if (filp
->f_op
->read
== tty_read
&&
2724 filp
->private_data
== tty
) {
2725 printk(KERN_NOTICE
"SAK: killed process %d"
2726 " (%s): fd#%d opened to the tty\n",
2727 task_pid_nr(p
), p
->comm
, i
);
2728 force_sig(SIGKILL
, p
);
2732 spin_unlock(&p
->files
->file_lock
);
2735 } while_each_thread(g
, p
);
2736 read_unlock(&tasklist_lock
);
2740 static void do_SAK_work(struct work_struct
*work
)
2742 struct tty_struct
*tty
=
2743 container_of(work
, struct tty_struct
, SAK_work
);
2748 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2749 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2750 * the values which we write to it will be identical to the values which it
2751 * already has. --akpm
2753 void do_SAK(struct tty_struct
*tty
)
2757 schedule_work(&tty
->SAK_work
);
2760 EXPORT_SYMBOL(do_SAK
);
2763 * initialize_tty_struct
2764 * @tty: tty to initialize
2766 * This subroutine initializes a tty structure that has been newly
2769 * Locking: none - tty in question must not be exposed at this point
2772 void initialize_tty_struct(struct tty_struct
*tty
,
2773 struct tty_driver
*driver
, int idx
)
2775 memset(tty
, 0, sizeof(struct tty_struct
));
2776 kref_init(&tty
->kref
);
2777 tty
->magic
= TTY_MAGIC
;
2778 tty_ldisc_init(tty
);
2779 tty
->session
= NULL
;
2781 tty
->overrun_time
= jiffies
;
2782 tty
->buf
.head
= tty
->buf
.tail
= NULL
;
2783 tty_buffer_init(tty
);
2784 mutex_init(&tty
->termios_mutex
);
2785 mutex_init(&tty
->ldisc_mutex
);
2786 init_waitqueue_head(&tty
->write_wait
);
2787 init_waitqueue_head(&tty
->read_wait
);
2788 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2789 mutex_init(&tty
->atomic_read_lock
);
2790 mutex_init(&tty
->atomic_write_lock
);
2791 mutex_init(&tty
->output_lock
);
2792 mutex_init(&tty
->echo_lock
);
2793 spin_lock_init(&tty
->read_lock
);
2794 spin_lock_init(&tty
->ctrl_lock
);
2795 INIT_LIST_HEAD(&tty
->tty_files
);
2796 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2798 tty
->driver
= driver
;
2799 tty
->ops
= driver
->ops
;
2801 tty_line_name(driver
, idx
, tty
->name
);
2805 * tty_put_char - write one character to a tty
2809 * Write one byte to the tty using the provided put_char method
2810 * if present. Returns the number of characters successfully output.
2812 * Note: the specific put_char operation in the driver layer may go
2813 * away soon. Don't call it directly, use this method
2816 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2818 if (tty
->ops
->put_char
)
2819 return tty
->ops
->put_char(tty
, ch
);
2820 return tty
->ops
->write(tty
, &ch
, 1);
2822 EXPORT_SYMBOL_GPL(tty_put_char
);
2824 struct class *tty_class
;
2827 * tty_register_device - register a tty device
2828 * @driver: the tty driver that describes the tty device
2829 * @index: the index in the tty driver for this tty device
2830 * @device: a struct device that is associated with this tty device.
2831 * This field is optional, if there is no known struct device
2832 * for this tty device it can be set to NULL safely.
2834 * Returns a pointer to the struct device for this tty device
2835 * (or ERR_PTR(-EFOO) on error).
2837 * This call is required to be made to register an individual tty device
2838 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2839 * that bit is not set, this function should not be called by a tty
2845 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
2846 struct device
*device
)
2849 dev_t dev
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
2851 if (index
>= driver
->num
) {
2852 printk(KERN_ERR
"Attempt to register invalid tty line number "
2854 return ERR_PTR(-EINVAL
);
2857 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
2858 pty_line_name(driver
, index
, name
);
2860 tty_line_name(driver
, index
, name
);
2862 return device_create(tty_class
, device
, dev
, NULL
, name
);
2864 EXPORT_SYMBOL(tty_register_device
);
2867 * tty_unregister_device - unregister a tty device
2868 * @driver: the tty driver that describes the tty device
2869 * @index: the index in the tty driver for this tty device
2871 * If a tty device is registered with a call to tty_register_device() then
2872 * this function must be called when the tty device is gone.
2877 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
2879 device_destroy(tty_class
,
2880 MKDEV(driver
->major
, driver
->minor_start
) + index
);
2882 EXPORT_SYMBOL(tty_unregister_device
);
2884 struct tty_driver
*alloc_tty_driver(int lines
)
2886 struct tty_driver
*driver
;
2888 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
2890 kref_init(&driver
->kref
);
2891 driver
->magic
= TTY_DRIVER_MAGIC
;
2892 driver
->num
= lines
;
2893 /* later we'll move allocation of tables here */
2897 EXPORT_SYMBOL(alloc_tty_driver
);
2899 static void destruct_tty_driver(struct kref
*kref
)
2901 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
2903 struct ktermios
*tp
;
2906 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
2908 * Free the termios and termios_locked structures because
2909 * we don't want to get memory leaks when modular tty
2910 * drivers are removed from the kernel.
2912 for (i
= 0; i
< driver
->num
; i
++) {
2913 tp
= driver
->termios
[i
];
2915 driver
->termios
[i
] = NULL
;
2918 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
2919 tty_unregister_device(driver
, i
);
2922 proc_tty_unregister_driver(driver
);
2923 driver
->ttys
= NULL
;
2924 driver
->termios
= NULL
;
2926 cdev_del(&driver
->cdev
);
2931 void tty_driver_kref_put(struct tty_driver
*driver
)
2933 kref_put(&driver
->kref
, destruct_tty_driver
);
2935 EXPORT_SYMBOL(tty_driver_kref_put
);
2937 void tty_set_operations(struct tty_driver
*driver
,
2938 const struct tty_operations
*op
)
2942 EXPORT_SYMBOL(tty_set_operations
);
2944 void put_tty_driver(struct tty_driver
*d
)
2946 tty_driver_kref_put(d
);
2948 EXPORT_SYMBOL(put_tty_driver
);
2951 * Called by a tty driver to register itself.
2953 int tty_register_driver(struct tty_driver
*driver
)
2960 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && driver
->num
) {
2961 p
= kzalloc(driver
->num
* 2 * sizeof(void *), GFP_KERNEL
);
2966 if (!driver
->major
) {
2967 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
2968 driver
->num
, driver
->name
);
2970 driver
->major
= MAJOR(dev
);
2971 driver
->minor_start
= MINOR(dev
);
2974 dev
= MKDEV(driver
->major
, driver
->minor_start
);
2975 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
2983 driver
->ttys
= (struct tty_struct
**)p
;
2984 driver
->termios
= (struct ktermios
**)(p
+ driver
->num
);
2986 driver
->ttys
= NULL
;
2987 driver
->termios
= NULL
;
2990 cdev_init(&driver
->cdev
, &tty_fops
);
2991 driver
->cdev
.owner
= driver
->owner
;
2992 error
= cdev_add(&driver
->cdev
, dev
, driver
->num
);
2994 unregister_chrdev_region(dev
, driver
->num
);
2995 driver
->ttys
= NULL
;
2996 driver
->termios
= NULL
;
3001 mutex_lock(&tty_mutex
);
3002 list_add(&driver
->tty_drivers
, &tty_drivers
);
3003 mutex_unlock(&tty_mutex
);
3005 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3006 for (i
= 0; i
< driver
->num
; i
++)
3007 tty_register_device(driver
, i
, NULL
);
3009 proc_tty_register_driver(driver
);
3010 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3014 EXPORT_SYMBOL(tty_register_driver
);
3017 * Called by a tty driver to unregister itself.
3019 int tty_unregister_driver(struct tty_driver
*driver
)
3023 if (driver
->refcount
)
3026 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3028 mutex_lock(&tty_mutex
);
3029 list_del(&driver
->tty_drivers
);
3030 mutex_unlock(&tty_mutex
);
3034 EXPORT_SYMBOL(tty_unregister_driver
);
3036 dev_t
tty_devnum(struct tty_struct
*tty
)
3038 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3040 EXPORT_SYMBOL(tty_devnum
);
3042 void proc_clear_tty(struct task_struct
*p
)
3044 unsigned long flags
;
3045 struct tty_struct
*tty
;
3046 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
3047 tty
= p
->signal
->tty
;
3048 p
->signal
->tty
= NULL
;
3049 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
3053 /* Called under the sighand lock */
3055 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3058 unsigned long flags
;
3059 /* We should not have a session or pgrp to put here but.... */
3060 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
3061 put_pid(tty
->session
);
3063 tty
->pgrp
= get_pid(task_pgrp(tsk
));
3064 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
3065 tty
->session
= get_pid(task_session(tsk
));
3066 if (tsk
->signal
->tty
) {
3067 printk(KERN_DEBUG
"tty not NULL!!\n");
3068 tty_kref_put(tsk
->signal
->tty
);
3071 put_pid(tsk
->signal
->tty_old_pgrp
);
3072 tsk
->signal
->tty
= tty_kref_get(tty
);
3073 tsk
->signal
->tty_old_pgrp
= NULL
;
3076 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3078 spin_lock_irq(&tsk
->sighand
->siglock
);
3079 __proc_set_tty(tsk
, tty
);
3080 spin_unlock_irq(&tsk
->sighand
->siglock
);
3083 struct tty_struct
*get_current_tty(void)
3085 struct tty_struct
*tty
;
3086 unsigned long flags
;
3088 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
3089 tty
= tty_kref_get(current
->signal
->tty
);
3090 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
3093 EXPORT_SYMBOL_GPL(get_current_tty
);
3095 void tty_default_fops(struct file_operations
*fops
)
3101 * Initialize the console device. This is called *early*, so
3102 * we can't necessarily depend on lots of kernel help here.
3103 * Just do some early initializations, and do the complex setup
3106 void __init
console_init(void)
3110 /* Setup the default TTY line discipline. */
3114 * set up the console device so that later boot sequences can
3115 * inform about problems etc..
3117 call
= __con_initcall_start
;
3118 while (call
< __con_initcall_end
) {
3124 static char *tty_devnode(struct device
*dev
, mode_t
*mode
)
3128 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3129 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3134 static int __init
tty_class_init(void)
3136 tty_class
= class_create(THIS_MODULE
, "tty");
3137 if (IS_ERR(tty_class
))
3138 return PTR_ERR(tty_class
);
3139 tty_class
->devnode
= tty_devnode
;
3143 postcore_initcall(tty_class_init
);
3145 /* 3/2004 jmc: why do these devices exist? */
3147 static struct cdev tty_cdev
, console_cdev
;
3150 * Ok, now we can initialize the rest of the tty devices and can count
3151 * on memory allocations, interrupts etc..
3153 int __init
tty_init(void)
3155 cdev_init(&tty_cdev
, &tty_fops
);
3156 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3157 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3158 panic("Couldn't register /dev/tty driver\n");
3159 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
,
3162 cdev_init(&console_cdev
, &console_fops
);
3163 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3164 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3165 panic("Couldn't register /dev/console driver\n");
3166 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3170 vty_init(&console_fops
);