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 init_dev and 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 #ifdef CONFIG_UNIX98_PTYS
140 extern struct tty_driver
*ptm_driver
; /* Unix98 pty masters; for /dev/ptmx */
141 static int ptmx_open(struct inode
*, struct file
*);
144 static void initialize_tty_struct(struct tty_struct
*tty
);
146 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
147 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
148 ssize_t
redirected_tty_write(struct file
*, const char __user
*,
150 static unsigned int tty_poll(struct file
*, poll_table
*);
151 static int tty_open(struct inode
*, struct file
*);
152 static int tty_release(struct inode
*, struct file
*);
153 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
);
155 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
158 #define tty_compat_ioctl NULL
160 static int tty_fasync(int fd
, struct file
*filp
, int on
);
161 static void release_tty(struct tty_struct
*tty
, int idx
);
162 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
163 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
166 * alloc_tty_struct - allocate a tty object
168 * Return a new empty tty structure. The data fields have not
169 * been initialized in any way but has been zeroed
174 static struct tty_struct
*alloc_tty_struct(void)
176 return kzalloc(sizeof(struct tty_struct
), GFP_KERNEL
);
179 static void tty_buffer_free_all(struct tty_struct
*);
182 * free_tty_struct - free a disused tty
183 * @tty: tty struct to free
185 * Free the write buffers, tty queue and tty memory itself.
187 * Locking: none. Must be called after tty is definitely unused
190 static inline void free_tty_struct(struct tty_struct
*tty
)
192 kfree(tty
->write_buf
);
193 tty_buffer_free_all(tty
);
197 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
200 * tty_name - return tty naming
201 * @tty: tty structure
202 * @buf: buffer for output
204 * Convert a tty structure into a name. The name reflects the kernel
205 * naming policy and if udev is in use may not reflect user space
210 char *tty_name(struct tty_struct
*tty
, char *buf
)
212 if (!tty
) /* Hmm. NULL pointer. That's fun. */
213 strcpy(buf
, "NULL tty");
215 strcpy(buf
, tty
->name
);
219 EXPORT_SYMBOL(tty_name
);
221 int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
224 #ifdef TTY_PARANOIA_CHECK
227 "null TTY for (%d:%d) in %s\n",
228 imajor(inode
), iminor(inode
), routine
);
231 if (tty
->magic
!= TTY_MAGIC
) {
233 "bad magic number for tty struct (%d:%d) in %s\n",
234 imajor(inode
), iminor(inode
), routine
);
241 static int check_tty_count(struct tty_struct
*tty
, const char *routine
)
243 #ifdef CHECK_TTY_COUNT
248 list_for_each(p
, &tty
->tty_files
) {
252 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
253 tty
->driver
->subtype
== PTY_TYPE_SLAVE
&&
254 tty
->link
&& tty
->link
->count
)
256 if (tty
->count
!= count
) {
257 printk(KERN_WARNING
"Warning: dev (%s) tty->count(%d) "
258 "!= #fd's(%d) in %s\n",
259 tty
->name
, tty
->count
, count
, routine
);
267 * Tty buffer allocation management
271 * tty_buffer_free_all - free buffers used by a tty
272 * @tty: tty to free from
274 * Remove all the buffers pending on a tty whether queued with data
275 * or in the free ring. Must be called when the tty is no longer in use
280 static void tty_buffer_free_all(struct tty_struct
*tty
)
282 struct tty_buffer
*thead
;
283 while ((thead
= tty
->buf
.head
) != NULL
) {
284 tty
->buf
.head
= thead
->next
;
287 while ((thead
= tty
->buf
.free
) != NULL
) {
288 tty
->buf
.free
= thead
->next
;
291 tty
->buf
.tail
= NULL
;
292 tty
->buf
.memory_used
= 0;
296 * tty_buffer_init - prepare a tty buffer structure
297 * @tty: tty to initialise
299 * Set up the initial state of the buffer management for a tty device.
300 * Must be called before the other tty buffer functions are used.
305 static void tty_buffer_init(struct tty_struct
*tty
)
307 spin_lock_init(&tty
->buf
.lock
);
308 tty
->buf
.head
= NULL
;
309 tty
->buf
.tail
= NULL
;
310 tty
->buf
.free
= NULL
;
311 tty
->buf
.memory_used
= 0;
315 * tty_buffer_alloc - allocate a tty buffer
317 * @size: desired size (characters)
319 * Allocate a new tty buffer to hold the desired number of characters.
320 * Return NULL if out of memory or the allocation would exceed the
323 * Locking: Caller must hold tty->buf.lock
326 static struct tty_buffer
*tty_buffer_alloc(struct tty_struct
*tty
, size_t size
)
328 struct tty_buffer
*p
;
330 if (tty
->buf
.memory_used
+ size
> 65536)
332 p
= kmalloc(sizeof(struct tty_buffer
) + 2 * size
, GFP_ATOMIC
);
340 p
->char_buf_ptr
= (char *)(p
->data
);
341 p
->flag_buf_ptr
= (unsigned char *)p
->char_buf_ptr
+ size
;
342 tty
->buf
.memory_used
+= size
;
347 * tty_buffer_free - free a tty buffer
348 * @tty: tty owning the buffer
349 * @b: the buffer to free
351 * Free a tty buffer, or add it to the free list according to our
354 * Locking: Caller must hold tty->buf.lock
357 static void tty_buffer_free(struct tty_struct
*tty
, struct tty_buffer
*b
)
359 /* Dumb strategy for now - should keep some stats */
360 tty
->buf
.memory_used
-= b
->size
;
361 WARN_ON(tty
->buf
.memory_used
< 0);
366 b
->next
= tty
->buf
.free
;
372 * __tty_buffer_flush - flush full tty buffers
375 * flush all the buffers containing receive data. Caller must
376 * hold the buffer lock and must have ensured no parallel flush to
379 * Locking: Caller must hold tty->buf.lock
382 static void __tty_buffer_flush(struct tty_struct
*tty
)
384 struct tty_buffer
*thead
;
386 while ((thead
= tty
->buf
.head
) != NULL
) {
387 tty
->buf
.head
= thead
->next
;
388 tty_buffer_free(tty
, thead
);
390 tty
->buf
.tail
= NULL
;
394 * tty_buffer_flush - flush full tty buffers
397 * flush all the buffers containing receive data. If the buffer is
398 * being processed by flush_to_ldisc then we defer the processing
404 static void tty_buffer_flush(struct tty_struct
*tty
)
407 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
409 /* If the data is being pushed to the tty layer then we can't
410 process it here. Instead set a flag and the flush_to_ldisc
411 path will process the flush request before it exits */
412 if (test_bit(TTY_FLUSHING
, &tty
->flags
)) {
413 set_bit(TTY_FLUSHPENDING
, &tty
->flags
);
414 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
415 wait_event(tty
->read_wait
,
416 test_bit(TTY_FLUSHPENDING
, &tty
->flags
) == 0);
419 __tty_buffer_flush(tty
);
420 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
424 * tty_buffer_find - find a free tty buffer
425 * @tty: tty owning the buffer
426 * @size: characters wanted
428 * Locate an existing suitable tty buffer or if we are lacking one then
429 * allocate a new one. We round our buffers off in 256 character chunks
430 * to get better allocation behaviour.
432 * Locking: Caller must hold tty->buf.lock
435 static struct tty_buffer
*tty_buffer_find(struct tty_struct
*tty
, size_t size
)
437 struct tty_buffer
**tbh
= &tty
->buf
.free
;
438 while ((*tbh
) != NULL
) {
439 struct tty_buffer
*t
= *tbh
;
440 if (t
->size
>= size
) {
446 tty
->buf
.memory_used
+= t
->size
;
449 tbh
= &((*tbh
)->next
);
451 /* Round the buffer size out */
452 size
= (size
+ 0xFF) & ~0xFF;
453 return tty_buffer_alloc(tty
, size
);
454 /* Should possibly check if this fails for the largest buffer we
455 have queued and recycle that ? */
459 * tty_buffer_request_room - grow tty buffer if needed
460 * @tty: tty structure
461 * @size: size desired
463 * Make at least size bytes of linear space available for the tty
464 * buffer. If we fail return the size we managed to find.
466 * Locking: Takes tty->buf.lock
468 int tty_buffer_request_room(struct tty_struct
*tty
, size_t size
)
470 struct tty_buffer
*b
, *n
;
474 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
476 /* OPTIMISATION: We could keep a per tty "zero" sized buffer to
477 remove this conditional if its worth it. This would be invisible
479 if ((b
= tty
->buf
.tail
) != NULL
)
480 left
= b
->size
- b
->used
;
485 /* This is the slow path - looking for new buffers to use */
486 if ((n
= tty_buffer_find(tty
, size
)) != NULL
) {
497 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
500 EXPORT_SYMBOL_GPL(tty_buffer_request_room
);
503 * tty_insert_flip_string - Add characters to the tty buffer
504 * @tty: tty structure
508 * Queue a series of bytes to the tty buffering. All the characters
509 * passed are marked as without error. Returns the number added.
511 * Locking: Called functions may take tty->buf.lock
514 int tty_insert_flip_string(struct tty_struct
*tty
, const unsigned char *chars
,
519 int space
= tty_buffer_request_room(tty
, size
- copied
);
520 struct tty_buffer
*tb
= tty
->buf
.tail
;
521 /* If there is no space then tb may be NULL */
522 if (unlikely(space
== 0))
524 memcpy(tb
->char_buf_ptr
+ tb
->used
, chars
, space
);
525 memset(tb
->flag_buf_ptr
+ tb
->used
, TTY_NORMAL
, space
);
529 /* There is a small chance that we need to split the data over
530 several buffers. If this is the case we must loop */
531 } while (unlikely(size
> copied
));
534 EXPORT_SYMBOL(tty_insert_flip_string
);
537 * tty_insert_flip_string_flags - Add characters to the tty buffer
538 * @tty: tty structure
543 * Queue a series of bytes to the tty buffering. For each character
544 * the flags array indicates the status of the character. Returns the
547 * Locking: Called functions may take tty->buf.lock
550 int tty_insert_flip_string_flags(struct tty_struct
*tty
,
551 const unsigned char *chars
, const char *flags
, size_t size
)
555 int space
= tty_buffer_request_room(tty
, size
- copied
);
556 struct tty_buffer
*tb
= tty
->buf
.tail
;
557 /* If there is no space then tb may be NULL */
558 if (unlikely(space
== 0))
560 memcpy(tb
->char_buf_ptr
+ tb
->used
, chars
, space
);
561 memcpy(tb
->flag_buf_ptr
+ tb
->used
, flags
, space
);
566 /* There is a small chance that we need to split the data over
567 several buffers. If this is the case we must loop */
568 } while (unlikely(size
> copied
));
571 EXPORT_SYMBOL(tty_insert_flip_string_flags
);
574 * tty_schedule_flip - push characters to ldisc
575 * @tty: tty to push from
577 * Takes any pending buffers and transfers their ownership to the
578 * ldisc side of the queue. It then schedules those characters for
579 * processing by the line discipline.
581 * Locking: Takes tty->buf.lock
584 void tty_schedule_flip(struct tty_struct
*tty
)
587 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
588 if (tty
->buf
.tail
!= NULL
)
589 tty
->buf
.tail
->commit
= tty
->buf
.tail
->used
;
590 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
591 schedule_delayed_work(&tty
->buf
.work
, 1);
593 EXPORT_SYMBOL(tty_schedule_flip
);
596 * tty_prepare_flip_string - make room for characters
598 * @chars: return pointer for character write area
599 * @size: desired size
601 * Prepare a block of space in the buffer for data. Returns the length
602 * available and buffer pointer to the space which is now allocated and
603 * accounted for as ready for normal characters. This is used for drivers
604 * that need their own block copy routines into the buffer. There is no
605 * guarantee the buffer is a DMA target!
607 * Locking: May call functions taking tty->buf.lock
610 int tty_prepare_flip_string(struct tty_struct
*tty
, unsigned char **chars
,
613 int space
= tty_buffer_request_room(tty
, size
);
615 struct tty_buffer
*tb
= tty
->buf
.tail
;
616 *chars
= tb
->char_buf_ptr
+ tb
->used
;
617 memset(tb
->flag_buf_ptr
+ tb
->used
, TTY_NORMAL
, space
);
623 EXPORT_SYMBOL_GPL(tty_prepare_flip_string
);
626 * tty_prepare_flip_string_flags - make room for characters
628 * @chars: return pointer for character write area
629 * @flags: return pointer for status flag write area
630 * @size: desired size
632 * Prepare a block of space in the buffer for data. Returns the length
633 * available and buffer pointer to the space which is now allocated and
634 * accounted for as ready for characters. This is used for drivers
635 * that need their own block copy routines into the buffer. There is no
636 * guarantee the buffer is a DMA target!
638 * Locking: May call functions taking tty->buf.lock
641 int tty_prepare_flip_string_flags(struct tty_struct
*tty
,
642 unsigned char **chars
, char **flags
, size_t size
)
644 int space
= tty_buffer_request_room(tty
, size
);
646 struct tty_buffer
*tb
= tty
->buf
.tail
;
647 *chars
= tb
->char_buf_ptr
+ tb
->used
;
648 *flags
= tb
->flag_buf_ptr
+ tb
->used
;
654 EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags
);
659 * tty_set_termios_ldisc - set ldisc field
660 * @tty: tty structure
661 * @num: line discipline number
663 * This is probably overkill for real world processors but
664 * they are not on hot paths so a little discipline won't do
667 * Locking: takes termios_mutex
670 static void tty_set_termios_ldisc(struct tty_struct
*tty
, int num
)
672 mutex_lock(&tty
->termios_mutex
);
673 tty
->termios
->c_line
= num
;
674 mutex_unlock(&tty
->termios_mutex
);
678 * This guards the refcounted line discipline lists. The lock
679 * must be taken with irqs off because there are hangup path
680 * callers who will do ldisc lookups and cannot sleep.
683 static DEFINE_SPINLOCK(tty_ldisc_lock
);
684 static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait
);
685 /* Line disc dispatch table */
686 static struct tty_ldisc_ops
*tty_ldiscs
[NR_LDISCS
];
689 * tty_register_ldisc - install a line discipline
690 * @disc: ldisc number
691 * @new_ldisc: pointer to the ldisc object
693 * Installs a new line discipline into the kernel. The discipline
694 * is set up as unreferenced and then made available to the kernel
695 * from this point onwards.
698 * takes tty_ldisc_lock to guard against ldisc races
701 int tty_register_ldisc(int disc
, struct tty_ldisc_ops
*new_ldisc
)
706 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
709 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
710 tty_ldiscs
[disc
] = new_ldisc
;
711 new_ldisc
->num
= disc
;
712 new_ldisc
->refcount
= 0;
713 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
717 EXPORT_SYMBOL(tty_register_ldisc
);
720 * tty_unregister_ldisc - unload a line discipline
721 * @disc: ldisc number
722 * @new_ldisc: pointer to the ldisc object
724 * Remove a line discipline from the kernel providing it is not
728 * takes tty_ldisc_lock to guard against ldisc races
731 int tty_unregister_ldisc(int disc
)
736 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
739 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
740 if (tty_ldiscs
[disc
]->refcount
)
743 tty_ldiscs
[disc
] = NULL
;
744 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
748 EXPORT_SYMBOL(tty_unregister_ldisc
);
752 * tty_ldisc_try_get - try and reference an ldisc
753 * @disc: ldisc number
754 * @ld: tty ldisc structure to complete
756 * Attempt to open and lock a line discipline into place. Return
757 * the line discipline refcounted and assigned in ld. On an error
758 * report the error code back
761 static int tty_ldisc_try_get(int disc
, struct tty_ldisc
*ld
)
764 struct tty_ldisc_ops
*ldops
;
767 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
769 ldops
= tty_ldiscs
[disc
];
770 /* Check the entry is defined */
772 /* If the module is being unloaded we can't use it */
773 if (!try_module_get(ldops
->owner
))
782 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
787 * tty_ldisc_get - take a reference to an ldisc
788 * @disc: ldisc number
789 * @ld: tty line discipline structure to use
791 * Takes a reference to a line discipline. Deals with refcounts and
792 * module locking counts. Returns NULL if the discipline is not available.
793 * Returns a pointer to the discipline and bumps the ref count if it is
797 * takes tty_ldisc_lock to guard against ldisc races
800 static int tty_ldisc_get(int disc
, struct tty_ldisc
*ld
)
804 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
806 err
= tty_ldisc_try_get(disc
, ld
);
807 if (err
== -EAGAIN
) {
808 request_module("tty-ldisc-%d", disc
);
809 err
= tty_ldisc_try_get(disc
, ld
);
815 * tty_ldisc_put - drop ldisc reference
816 * @disc: ldisc number
818 * Drop a reference to a line discipline. Manage refcounts and
819 * module usage counts
822 * takes tty_ldisc_lock to guard against ldisc races
825 static void tty_ldisc_put(struct tty_ldisc_ops
*ld
)
830 BUG_ON(disc
< N_TTY
|| disc
>= NR_LDISCS
);
832 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
833 ld
= tty_ldiscs
[disc
];
834 BUG_ON(ld
->refcount
== 0);
836 module_put(ld
->owner
);
837 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
840 static void * tty_ldiscs_seq_start(struct seq_file
*m
, loff_t
*pos
)
842 return (*pos
< NR_LDISCS
) ? pos
: NULL
;
845 static void * tty_ldiscs_seq_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
848 return (*pos
< NR_LDISCS
) ? pos
: NULL
;
851 static void tty_ldiscs_seq_stop(struct seq_file
*m
, void *v
)
855 static int tty_ldiscs_seq_show(struct seq_file
*m
, void *v
)
857 int i
= *(loff_t
*)v
;
860 if (tty_ldisc_get(i
, &ld
) < 0)
862 seq_printf(m
, "%-10s %2d\n", ld
.ops
->name
? ld
.ops
->name
: "???", i
);
863 tty_ldisc_put(ld
.ops
);
867 static const struct seq_operations tty_ldiscs_seq_ops
= {
868 .start
= tty_ldiscs_seq_start
,
869 .next
= tty_ldiscs_seq_next
,
870 .stop
= tty_ldiscs_seq_stop
,
871 .show
= tty_ldiscs_seq_show
,
874 static int proc_tty_ldiscs_open(struct inode
*inode
, struct file
*file
)
876 return seq_open(file
, &tty_ldiscs_seq_ops
);
879 const struct file_operations tty_ldiscs_proc_fops
= {
880 .owner
= THIS_MODULE
,
881 .open
= proc_tty_ldiscs_open
,
884 .release
= seq_release
,
888 * tty_ldisc_assign - set ldisc on a tty
889 * @tty: tty to assign
890 * @ld: line discipline
892 * Install an instance of a line discipline into a tty structure. The
893 * ldisc must have a reference count above zero to ensure it remains/
894 * The tty instance refcount starts at zero.
897 * Caller must hold references
900 static void tty_ldisc_assign(struct tty_struct
*tty
, struct tty_ldisc
*ld
)
907 * tty_ldisc_try - internal helper
910 * Make a single attempt to grab and bump the refcount on
911 * the tty ldisc. Return 0 on failure or 1 on success. This is
912 * used to implement both the waiting and non waiting versions
915 * Locking: takes tty_ldisc_lock
918 static int tty_ldisc_try(struct tty_struct
*tty
)
921 struct tty_ldisc
*ld
;
924 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
926 if (test_bit(TTY_LDISC
, &tty
->flags
)) {
930 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
935 * tty_ldisc_ref_wait - wait for the tty ldisc
938 * Dereference the line discipline for the terminal and take a
939 * reference to it. If the line discipline is in flux then
940 * wait patiently until it changes.
942 * Note: Must not be called from an IRQ/timer context. The caller
943 * must also be careful not to hold other locks that will deadlock
944 * against a discipline change, such as an existing ldisc reference
945 * (which we check for)
947 * Locking: call functions take tty_ldisc_lock
950 struct tty_ldisc
*tty_ldisc_ref_wait(struct tty_struct
*tty
)
952 /* wait_event is a macro */
953 wait_event(tty_ldisc_wait
, tty_ldisc_try(tty
));
954 if (tty
->ldisc
.refcount
== 0)
955 printk(KERN_ERR
"tty_ldisc_ref_wait\n");
959 EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait
);
962 * tty_ldisc_ref - get the tty ldisc
965 * Dereference the line discipline for the terminal and take a
966 * reference to it. If the line discipline is in flux then
967 * return NULL. Can be called from IRQ and timer functions.
969 * Locking: called functions take tty_ldisc_lock
972 struct tty_ldisc
*tty_ldisc_ref(struct tty_struct
*tty
)
974 if (tty_ldisc_try(tty
))
979 EXPORT_SYMBOL_GPL(tty_ldisc_ref
);
982 * tty_ldisc_deref - free a tty ldisc reference
983 * @ld: reference to free up
985 * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May
986 * be called in IRQ context.
988 * Locking: takes tty_ldisc_lock
991 void tty_ldisc_deref(struct tty_ldisc
*ld
)
997 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
998 if (ld
->refcount
== 0)
999 printk(KERN_ERR
"tty_ldisc_deref: no references.\n");
1002 if (ld
->refcount
== 0)
1003 wake_up(&tty_ldisc_wait
);
1004 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1007 EXPORT_SYMBOL_GPL(tty_ldisc_deref
);
1010 * tty_ldisc_enable - allow ldisc use
1011 * @tty: terminal to activate ldisc on
1013 * Set the TTY_LDISC flag when the line discipline can be called
1014 * again. Do necessary wakeups for existing sleepers.
1016 * Note: nobody should set this bit except via this function. Clearing
1017 * directly is allowed.
1020 static void tty_ldisc_enable(struct tty_struct
*tty
)
1022 set_bit(TTY_LDISC
, &tty
->flags
);
1023 wake_up(&tty_ldisc_wait
);
1027 * tty_ldisc_restore - helper for tty ldisc change
1028 * @tty: tty to recover
1029 * @old: previous ldisc
1031 * Restore the previous line discipline or N_TTY when a line discipline
1032 * change fails due to an open error
1035 static void tty_ldisc_restore(struct tty_struct
*tty
, struct tty_ldisc
*old
)
1038 struct tty_ldisc new_ldisc
;
1040 /* There is an outstanding reference here so this is safe */
1041 tty_ldisc_get(old
->ops
->num
, old
);
1042 tty_ldisc_assign(tty
, old
);
1043 tty_set_termios_ldisc(tty
, old
->ops
->num
);
1044 if (old
->ops
->open
&& (old
->ops
->open(tty
) < 0)) {
1045 tty_ldisc_put(old
->ops
);
1046 /* This driver is always present */
1047 if (tty_ldisc_get(N_TTY
, &new_ldisc
) < 0)
1048 panic("n_tty: get");
1049 tty_ldisc_assign(tty
, &new_ldisc
);
1050 tty_set_termios_ldisc(tty
, N_TTY
);
1051 if (new_ldisc
.ops
->open
) {
1052 int r
= new_ldisc
.ops
->open(tty
);
1054 panic("Couldn't open N_TTY ldisc for "
1056 tty_name(tty
, buf
), r
);
1062 * tty_set_ldisc - set line discipline
1063 * @tty: the terminal to set
1064 * @ldisc: the line discipline
1066 * Set the discipline of a tty line. Must be called from a process
1069 * Locking: takes tty_ldisc_lock.
1070 * called functions take termios_mutex
1073 static int tty_set_ldisc(struct tty_struct
*tty
, int ldisc
)
1076 struct tty_ldisc o_ldisc
, new_ldisc
;
1078 unsigned long flags
;
1079 struct tty_struct
*o_tty
;
1082 /* This is a bit ugly for now but means we can break the 'ldisc
1083 is part of the tty struct' assumption later */
1084 retval
= tty_ldisc_get(ldisc
, &new_ldisc
);
1089 * Problem: What do we do if this blocks ?
1092 tty_wait_until_sent(tty
, 0);
1094 if (tty
->ldisc
.ops
->num
== ldisc
) {
1095 tty_ldisc_put(new_ldisc
.ops
);
1100 * No more input please, we are switching. The new ldisc
1101 * will update this value in the ldisc open function
1104 tty
->receive_room
= 0;
1106 o_ldisc
= tty
->ldisc
;
1110 * Make sure we don't change while someone holds a
1111 * reference to the line discipline. The TTY_LDISC bit
1112 * prevents anyone taking a reference once it is clear.
1113 * We need the lock to avoid racing reference takers.
1116 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
1117 if (tty
->ldisc
.refcount
|| (o_tty
&& o_tty
->ldisc
.refcount
)) {
1118 if (tty
->ldisc
.refcount
) {
1119 /* Free the new ldisc we grabbed. Must drop the lock
1121 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1122 tty_ldisc_put(o_ldisc
.ops
);
1124 * There are several reasons we may be busy, including
1125 * random momentary I/O traffic. We must therefore
1126 * retry. We could distinguish between blocking ops
1127 * and retries if we made tty_ldisc_wait() smarter.
1128 * That is up for discussion.
1130 if (wait_event_interruptible(tty_ldisc_wait
, tty
->ldisc
.refcount
== 0) < 0)
1131 return -ERESTARTSYS
;
1134 if (o_tty
&& o_tty
->ldisc
.refcount
) {
1135 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1136 tty_ldisc_put(o_tty
->ldisc
.ops
);
1137 if (wait_event_interruptible(tty_ldisc_wait
, o_tty
->ldisc
.refcount
== 0) < 0)
1138 return -ERESTARTSYS
;
1143 * If the TTY_LDISC bit is set, then we are racing against
1144 * another ldisc change
1146 if (!test_bit(TTY_LDISC
, &tty
->flags
)) {
1147 struct tty_ldisc
*ld
;
1148 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1149 tty_ldisc_put(new_ldisc
.ops
);
1150 ld
= tty_ldisc_ref_wait(tty
);
1151 tty_ldisc_deref(ld
);
1155 clear_bit(TTY_LDISC
, &tty
->flags
);
1157 clear_bit(TTY_LDISC
, &o_tty
->flags
);
1158 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1161 * From this point on we know nobody has an ldisc
1162 * usage reference, nor can they obtain one until
1163 * we say so later on.
1166 work
= cancel_delayed_work(&tty
->buf
.work
);
1168 * Wait for ->hangup_work and ->buf.work handlers to terminate
1169 * MUST NOT hold locks here.
1171 flush_scheduled_work();
1172 /* Shutdown the current discipline. */
1173 if (o_ldisc
.ops
->close
)
1174 (o_ldisc
.ops
->close
)(tty
);
1176 /* Now set up the new line discipline. */
1177 tty_ldisc_assign(tty
, &new_ldisc
);
1178 tty_set_termios_ldisc(tty
, ldisc
);
1179 if (new_ldisc
.ops
->open
)
1180 retval
= (new_ldisc
.ops
->open
)(tty
);
1182 tty_ldisc_put(new_ldisc
.ops
);
1183 tty_ldisc_restore(tty
, &o_ldisc
);
1185 /* At this point we hold a reference to the new ldisc and a
1186 a reference to the old ldisc. If we ended up flipping back
1187 to the existing ldisc we have two references to it */
1189 if (tty
->ldisc
.ops
->num
!= o_ldisc
.ops
->num
&& tty
->ops
->set_ldisc
)
1190 tty
->ops
->set_ldisc(tty
);
1192 tty_ldisc_put(o_ldisc
.ops
);
1195 * Allow ldisc referencing to occur as soon as the driver
1196 * ldisc callback completes.
1199 tty_ldisc_enable(tty
);
1201 tty_ldisc_enable(o_tty
);
1203 /* Restart it in case no characters kick it off. Safe if
1206 schedule_delayed_work(&tty
->buf
.work
, 1);
1211 * get_tty_driver - find device of a tty
1212 * @dev_t: device identifier
1213 * @index: returns the index of the tty
1215 * This routine returns a tty driver structure, given a device number
1216 * and also passes back the index number.
1218 * Locking: caller must hold tty_mutex
1221 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
1223 struct tty_driver
*p
;
1225 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
1226 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
1227 if (device
< base
|| device
>= base
+ p
->num
)
1229 *index
= device
- base
;
1235 #ifdef CONFIG_CONSOLE_POLL
1238 * tty_find_polling_driver - find device of a polled tty
1239 * @name: name string to match
1240 * @line: pointer to resulting tty line nr
1242 * This routine returns a tty driver structure, given a name
1243 * and the condition that the tty driver is capable of polled
1246 struct tty_driver
*tty_find_polling_driver(char *name
, int *line
)
1248 struct tty_driver
*p
, *res
= NULL
;
1252 mutex_lock(&tty_mutex
);
1253 /* Search through the tty devices to look for a match */
1254 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
1255 str
= name
+ strlen(p
->name
);
1256 tty_line
= simple_strtoul(str
, &str
, 10);
1262 if (tty_line
>= 0 && tty_line
<= p
->num
&& p
->ops
&&
1263 p
->ops
->poll_init
&& !p
->ops
->poll_init(p
, tty_line
, str
)) {
1269 mutex_unlock(&tty_mutex
);
1273 EXPORT_SYMBOL_GPL(tty_find_polling_driver
);
1277 * tty_check_change - check for POSIX terminal changes
1278 * @tty: tty to check
1280 * If we try to write to, or set the state of, a terminal and we're
1281 * not in the foreground, send a SIGTTOU. If the signal is blocked or
1282 * ignored, go ahead and perform the operation. (POSIX 7.2)
1284 * Locking: ctrl_lock
1287 int tty_check_change(struct tty_struct
*tty
)
1289 unsigned long flags
;
1292 if (current
->signal
->tty
!= tty
)
1295 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
1298 printk(KERN_WARNING
"tty_check_change: tty->pgrp == NULL!\n");
1301 if (task_pgrp(current
) == tty
->pgrp
)
1303 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1304 if (is_ignored(SIGTTOU
))
1306 if (is_current_pgrp_orphaned()) {
1310 kill_pgrp(task_pgrp(current
), SIGTTOU
, 1);
1311 set_thread_flag(TIF_SIGPENDING
);
1316 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1320 EXPORT_SYMBOL(tty_check_change
);
1322 static ssize_t
hung_up_tty_read(struct file
*file
, char __user
*buf
,
1323 size_t count
, loff_t
*ppos
)
1328 static ssize_t
hung_up_tty_write(struct file
*file
, const char __user
*buf
,
1329 size_t count
, loff_t
*ppos
)
1334 /* No kernel lock held - none needed ;) */
1335 static unsigned int hung_up_tty_poll(struct file
*filp
, poll_table
*wait
)
1337 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
1340 static long hung_up_tty_ioctl(struct file
*file
, unsigned int cmd
,
1343 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
1346 static long hung_up_tty_compat_ioctl(struct file
*file
,
1347 unsigned int cmd
, unsigned long arg
)
1349 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
1352 static const struct file_operations tty_fops
= {
1353 .llseek
= no_llseek
,
1357 .unlocked_ioctl
= tty_ioctl
,
1358 .compat_ioctl
= tty_compat_ioctl
,
1360 .release
= tty_release
,
1361 .fasync
= tty_fasync
,
1364 #ifdef CONFIG_UNIX98_PTYS
1365 static const struct file_operations ptmx_fops
= {
1366 .llseek
= no_llseek
,
1370 .unlocked_ioctl
= tty_ioctl
,
1371 .compat_ioctl
= tty_compat_ioctl
,
1373 .release
= tty_release
,
1374 .fasync
= tty_fasync
,
1378 static const struct file_operations console_fops
= {
1379 .llseek
= no_llseek
,
1381 .write
= redirected_tty_write
,
1383 .unlocked_ioctl
= tty_ioctl
,
1384 .compat_ioctl
= tty_compat_ioctl
,
1386 .release
= tty_release
,
1387 .fasync
= tty_fasync
,
1390 static const struct file_operations hung_up_tty_fops
= {
1391 .llseek
= no_llseek
,
1392 .read
= hung_up_tty_read
,
1393 .write
= hung_up_tty_write
,
1394 .poll
= hung_up_tty_poll
,
1395 .unlocked_ioctl
= hung_up_tty_ioctl
,
1396 .compat_ioctl
= hung_up_tty_compat_ioctl
,
1397 .release
= tty_release
,
1400 static DEFINE_SPINLOCK(redirect_lock
);
1401 static struct file
*redirect
;
1404 * tty_wakeup - request more data
1407 * Internal and external helper for wakeups of tty. This function
1408 * informs the line discipline if present that the driver is ready
1409 * to receive more output data.
1412 void tty_wakeup(struct tty_struct
*tty
)
1414 struct tty_ldisc
*ld
;
1416 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
1417 ld
= tty_ldisc_ref(tty
);
1419 if (ld
->ops
->write_wakeup
)
1420 ld
->ops
->write_wakeup(tty
);
1421 tty_ldisc_deref(ld
);
1424 wake_up_interruptible(&tty
->write_wait
);
1427 EXPORT_SYMBOL_GPL(tty_wakeup
);
1430 * tty_ldisc_flush - flush line discipline queue
1433 * Flush the line discipline queue (if any) for this tty. If there
1434 * is no line discipline active this is a no-op.
1437 void tty_ldisc_flush(struct tty_struct
*tty
)
1439 struct tty_ldisc
*ld
= tty_ldisc_ref(tty
);
1441 if (ld
->ops
->flush_buffer
)
1442 ld
->ops
->flush_buffer(tty
);
1443 tty_ldisc_deref(ld
);
1445 tty_buffer_flush(tty
);
1448 EXPORT_SYMBOL_GPL(tty_ldisc_flush
);
1451 * tty_reset_termios - reset terminal state
1452 * @tty: tty to reset
1454 * Restore a terminal to the driver default state
1457 static void tty_reset_termios(struct tty_struct
*tty
)
1459 mutex_lock(&tty
->termios_mutex
);
1460 *tty
->termios
= tty
->driver
->init_termios
;
1461 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
1462 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
1463 mutex_unlock(&tty
->termios_mutex
);
1467 * do_tty_hangup - actual handler for hangup events
1470 k * This can be called by the "eventd" kernel thread. That is process
1471 * synchronous but doesn't hold any locks, so we need to make sure we
1472 * have the appropriate locks for what we're doing.
1474 * The hangup event clears any pending redirections onto the hung up
1475 * device. It ensures future writes will error and it does the needed
1476 * line discipline hangup and signal delivery. The tty object itself
1481 * redirect lock for undoing redirection
1482 * file list lock for manipulating list of ttys
1483 * tty_ldisc_lock from called functions
1484 * termios_mutex resetting termios data
1485 * tasklist_lock to walk task list for hangup event
1486 * ->siglock to protect ->signal/->sighand
1488 static void do_tty_hangup(struct work_struct
*work
)
1490 struct tty_struct
*tty
=
1491 container_of(work
, struct tty_struct
, hangup_work
);
1492 struct file
*cons_filp
= NULL
;
1493 struct file
*filp
, *f
= NULL
;
1494 struct task_struct
*p
;
1495 struct tty_ldisc
*ld
;
1496 int closecount
= 0, n
;
1497 unsigned long flags
;
1502 /* inuse_filps is protected by the single kernel lock */
1505 spin_lock(&redirect_lock
);
1506 if (redirect
&& redirect
->private_data
== tty
) {
1510 spin_unlock(&redirect_lock
);
1512 check_tty_count(tty
, "do_tty_hangup");
1514 /* This breaks for file handles being sent over AF_UNIX sockets ? */
1515 list_for_each_entry(filp
, &tty
->tty_files
, f_u
.fu_list
) {
1516 if (filp
->f_op
->write
== redirected_tty_write
)
1518 if (filp
->f_op
->write
!= tty_write
)
1521 tty_fasync(-1, filp
, 0); /* can't block */
1522 filp
->f_op
= &hung_up_tty_fops
;
1526 * FIXME! What are the locking issues here? This may me overdoing
1527 * things... This question is especially important now that we've
1528 * removed the irqlock.
1530 ld
= tty_ldisc_ref(tty
);
1532 /* We may have no line discipline at this point */
1533 if (ld
->ops
->flush_buffer
)
1534 ld
->ops
->flush_buffer(tty
);
1535 tty_driver_flush_buffer(tty
);
1536 if ((test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) &&
1537 ld
->ops
->write_wakeup
)
1538 ld
->ops
->write_wakeup(tty
);
1539 if (ld
->ops
->hangup
)
1540 ld
->ops
->hangup(tty
);
1543 * FIXME: Once we trust the LDISC code better we can wait here for
1544 * ldisc completion and fix the driver call race
1546 wake_up_interruptible(&tty
->write_wait
);
1547 wake_up_interruptible(&tty
->read_wait
);
1549 * Shutdown the current line discipline, and reset it to
1552 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1553 tty_reset_termios(tty
);
1554 /* Defer ldisc switch */
1555 /* tty_deferred_ldisc_switch(N_TTY);
1557 This should get done automatically when the port closes and
1558 tty_release is called */
1560 read_lock(&tasklist_lock
);
1562 do_each_pid_task(tty
->session
, PIDTYPE_SID
, p
) {
1563 spin_lock_irq(&p
->sighand
->siglock
);
1564 if (p
->signal
->tty
== tty
)
1565 p
->signal
->tty
= NULL
;
1566 if (!p
->signal
->leader
) {
1567 spin_unlock_irq(&p
->sighand
->siglock
);
1570 __group_send_sig_info(SIGHUP
, SEND_SIG_PRIV
, p
);
1571 __group_send_sig_info(SIGCONT
, SEND_SIG_PRIV
, p
);
1572 put_pid(p
->signal
->tty_old_pgrp
); /* A noop */
1573 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
1575 p
->signal
->tty_old_pgrp
= get_pid(tty
->pgrp
);
1576 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1577 spin_unlock_irq(&p
->sighand
->siglock
);
1578 } while_each_pid_task(tty
->session
, PIDTYPE_SID
, p
);
1580 read_unlock(&tasklist_lock
);
1582 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
1584 put_pid(tty
->session
);
1586 tty
->session
= NULL
;
1588 tty
->ctrl_status
= 0;
1589 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1592 * If one of the devices matches a console pointer, we
1593 * cannot just call hangup() because that will cause
1594 * tty->count and state->count to go out of sync.
1595 * So we just call close() the right number of times.
1598 if (tty
->ops
->close
)
1599 for (n
= 0; n
< closecount
; n
++)
1600 tty
->ops
->close(tty
, cons_filp
);
1601 } else if (tty
->ops
->hangup
)
1602 (tty
->ops
->hangup
)(tty
);
1604 * We don't want to have driver/ldisc interactions beyond
1605 * the ones we did here. The driver layer expects no
1606 * calls after ->hangup() from the ldisc side. However we
1607 * can't yet guarantee all that.
1609 set_bit(TTY_HUPPED
, &tty
->flags
);
1611 tty_ldisc_enable(tty
);
1612 tty_ldisc_deref(ld
);
1620 * tty_hangup - trigger a hangup event
1621 * @tty: tty to hangup
1623 * A carrier loss (virtual or otherwise) has occurred on this like
1624 * schedule a hangup sequence to run after this event.
1627 void tty_hangup(struct tty_struct
*tty
)
1629 #ifdef TTY_DEBUG_HANGUP
1631 printk(KERN_DEBUG
"%s hangup...\n", tty_name(tty
, buf
));
1633 schedule_work(&tty
->hangup_work
);
1636 EXPORT_SYMBOL(tty_hangup
);
1639 * tty_vhangup - process vhangup
1640 * @tty: tty to hangup
1642 * The user has asked via system call for the terminal to be hung up.
1643 * We do this synchronously so that when the syscall returns the process
1644 * is complete. That guarantee is necessary for security reasons.
1647 void tty_vhangup(struct tty_struct
*tty
)
1649 #ifdef TTY_DEBUG_HANGUP
1652 printk(KERN_DEBUG
"%s vhangup...\n", tty_name(tty
, buf
));
1654 do_tty_hangup(&tty
->hangup_work
);
1657 EXPORT_SYMBOL(tty_vhangup
);
1660 * tty_hung_up_p - was tty hung up
1661 * @filp: file pointer of tty
1663 * Return true if the tty has been subject to a vhangup or a carrier
1667 int tty_hung_up_p(struct file
*filp
)
1669 return (filp
->f_op
== &hung_up_tty_fops
);
1672 EXPORT_SYMBOL(tty_hung_up_p
);
1675 * is_tty - checker whether file is a TTY
1676 * @filp: file handle that may be a tty
1678 * Check if the file handle is a tty handle.
1681 int is_tty(struct file
*filp
)
1683 return filp
->f_op
->read
== tty_read
1684 || filp
->f_op
->read
== hung_up_tty_read
;
1687 static void session_clear_tty(struct pid
*session
)
1689 struct task_struct
*p
;
1690 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
1692 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
1696 * disassociate_ctty - disconnect controlling tty
1697 * @on_exit: true if exiting so need to "hang up" the session
1699 * This function is typically called only by the session leader, when
1700 * it wants to disassociate itself from its controlling tty.
1702 * It performs the following functions:
1703 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
1704 * (2) Clears the tty from being controlling the session
1705 * (3) Clears the controlling tty for all processes in the
1708 * The argument on_exit is set to 1 if called when a process is
1709 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
1712 * BKL is taken for hysterical raisins
1713 * tty_mutex is taken to protect tty
1714 * ->siglock is taken to protect ->signal/->sighand
1715 * tasklist_lock is taken to walk process list for sessions
1716 * ->siglock is taken to protect ->signal/->sighand
1719 void disassociate_ctty(int on_exit
)
1721 struct tty_struct
*tty
;
1722 struct pid
*tty_pgrp
= NULL
;
1725 mutex_lock(&tty_mutex
);
1726 tty
= get_current_tty();
1728 tty_pgrp
= get_pid(tty
->pgrp
);
1729 mutex_unlock(&tty_mutex
);
1731 /* XXX: here we race, there is nothing protecting tty */
1732 if (on_exit
&& tty
->driver
->type
!= TTY_DRIVER_TYPE_PTY
)
1735 } else if (on_exit
) {
1736 struct pid
*old_pgrp
;
1737 spin_lock_irq(¤t
->sighand
->siglock
);
1738 old_pgrp
= current
->signal
->tty_old_pgrp
;
1739 current
->signal
->tty_old_pgrp
= NULL
;
1740 spin_unlock_irq(¤t
->sighand
->siglock
);
1742 kill_pgrp(old_pgrp
, SIGHUP
, on_exit
);
1743 kill_pgrp(old_pgrp
, SIGCONT
, on_exit
);
1746 mutex_unlock(&tty_mutex
);
1750 kill_pgrp(tty_pgrp
, SIGHUP
, on_exit
);
1752 kill_pgrp(tty_pgrp
, SIGCONT
, on_exit
);
1756 spin_lock_irq(¤t
->sighand
->siglock
);
1757 put_pid(current
->signal
->tty_old_pgrp
);
1758 current
->signal
->tty_old_pgrp
= NULL
;
1759 spin_unlock_irq(¤t
->sighand
->siglock
);
1761 mutex_lock(&tty_mutex
);
1762 /* It is possible that do_tty_hangup has free'd this tty */
1763 tty
= get_current_tty();
1765 unsigned long flags
;
1766 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
1767 put_pid(tty
->session
);
1769 tty
->session
= NULL
;
1771 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1773 #ifdef TTY_DEBUG_HANGUP
1774 printk(KERN_DEBUG
"error attempted to write to tty [0x%p]"
1778 mutex_unlock(&tty_mutex
);
1780 /* Now clear signal->tty under the lock */
1781 read_lock(&tasklist_lock
);
1782 session_clear_tty(task_session(current
));
1783 read_unlock(&tasklist_lock
);
1788 * no_tty - Ensure the current process does not have a controlling tty
1792 struct task_struct
*tsk
= current
;
1794 if (tsk
->signal
->leader
)
1795 disassociate_ctty(0);
1797 proc_clear_tty(tsk
);
1802 * stop_tty - propagate flow control
1805 * Perform flow control to the driver. For PTY/TTY pairs we
1806 * must also propagate the TIOCKPKT status. May be called
1807 * on an already stopped device and will not re-call the driver
1810 * This functionality is used by both the line disciplines for
1811 * halting incoming flow and by the driver. It may therefore be
1812 * called from any context, may be under the tty atomic_write_lock
1816 * Uses the tty control lock internally
1819 void stop_tty(struct tty_struct
*tty
)
1821 unsigned long flags
;
1822 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
1824 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1828 if (tty
->link
&& tty
->link
->packet
) {
1829 tty
->ctrl_status
&= ~TIOCPKT_START
;
1830 tty
->ctrl_status
|= TIOCPKT_STOP
;
1831 wake_up_interruptible(&tty
->link
->read_wait
);
1833 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1835 (tty
->ops
->stop
)(tty
);
1838 EXPORT_SYMBOL(stop_tty
);
1841 * start_tty - propagate flow control
1842 * @tty: tty to start
1844 * Start a tty that has been stopped if at all possible. Perform
1845 * any necessary wakeups and propagate the TIOCPKT status. If this
1846 * is the tty was previous stopped and is being started then the
1847 * driver start method is invoked and the line discipline woken.
1853 void start_tty(struct tty_struct
*tty
)
1855 unsigned long flags
;
1856 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
1857 if (!tty
->stopped
|| tty
->flow_stopped
) {
1858 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1862 if (tty
->link
&& tty
->link
->packet
) {
1863 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
1864 tty
->ctrl_status
|= TIOCPKT_START
;
1865 wake_up_interruptible(&tty
->link
->read_wait
);
1867 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
1868 if (tty
->ops
->start
)
1869 (tty
->ops
->start
)(tty
);
1870 /* If we have a running line discipline it may need kicking */
1874 EXPORT_SYMBOL(start_tty
);
1877 * tty_read - read method for tty device files
1878 * @file: pointer to tty file
1880 * @count: size of user buffer
1883 * Perform the read system call function on this terminal device. Checks
1884 * for hung up devices before calling the line discipline method.
1887 * Locks the line discipline internally while needed. Multiple
1888 * read calls may be outstanding in parallel.
1891 static ssize_t
tty_read(struct file
*file
, char __user
*buf
, size_t count
,
1895 struct tty_struct
*tty
;
1896 struct inode
*inode
;
1897 struct tty_ldisc
*ld
;
1899 tty
= (struct tty_struct
*)file
->private_data
;
1900 inode
= file
->f_path
.dentry
->d_inode
;
1901 if (tty_paranoia_check(tty
, inode
, "tty_read"))
1903 if (!tty
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1906 /* We want to wait for the line discipline to sort out in this
1908 ld
= tty_ldisc_ref_wait(tty
);
1910 i
= (ld
->ops
->read
)(tty
, file
, buf
, count
);
1913 tty_ldisc_deref(ld
);
1915 inode
->i_atime
= current_fs_time(inode
->i_sb
);
1919 void tty_write_unlock(struct tty_struct
*tty
)
1921 mutex_unlock(&tty
->atomic_write_lock
);
1922 wake_up_interruptible(&tty
->write_wait
);
1925 int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
1927 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
1930 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
1931 return -ERESTARTSYS
;
1937 * Split writes up in sane blocksizes to avoid
1938 * denial-of-service type attacks
1940 static inline ssize_t
do_tty_write(
1941 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
1942 struct tty_struct
*tty
,
1944 const char __user
*buf
,
1947 ssize_t ret
, written
= 0;
1950 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
1955 * We chunk up writes into a temporary buffer. This
1956 * simplifies low-level drivers immensely, since they
1957 * don't have locking issues and user mode accesses.
1959 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1962 * The default chunk-size is 2kB, because the NTTY
1963 * layer has problems with bigger chunks. It will
1964 * claim to be able to handle more characters than
1967 * FIXME: This can probably go away now except that 64K chunks
1968 * are too likely to fail unless switched to vmalloc...
1971 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
1976 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1977 if (tty
->write_cnt
< chunk
) {
1983 buf
= kmalloc(chunk
, GFP_KERNEL
);
1988 kfree(tty
->write_buf
);
1989 tty
->write_cnt
= chunk
;
1990 tty
->write_buf
= buf
;
1993 /* Do the write .. */
1995 size_t size
= count
;
1999 if (copy_from_user(tty
->write_buf
, buf
, size
))
2001 ret
= write(tty
, file
, tty
->write_buf
, size
);
2010 if (signal_pending(current
))
2015 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
2016 inode
->i_mtime
= current_fs_time(inode
->i_sb
);
2020 tty_write_unlock(tty
);
2026 * tty_write - write method for tty device file
2027 * @file: tty file pointer
2028 * @buf: user data to write
2029 * @count: bytes to write
2032 * Write data to a tty device via the line discipline.
2035 * Locks the line discipline as required
2036 * Writes to the tty driver are serialized by the atomic_write_lock
2037 * and are then processed in chunks to the device. The line discipline
2038 * write method will not be involked in parallel for each device
2039 * The line discipline write method is called under the big
2040 * kernel lock for historical reasons. New code should not rely on this.
2043 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
2044 size_t count
, loff_t
*ppos
)
2046 struct tty_struct
*tty
;
2047 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
2049 struct tty_ldisc
*ld
;
2051 tty
= (struct tty_struct
*)file
->private_data
;
2052 if (tty_paranoia_check(tty
, inode
, "tty_write"))
2054 if (!tty
|| !tty
->ops
->write
||
2055 (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
2057 /* Short term debug to catch buggy drivers */
2058 if (tty
->ops
->write_room
== NULL
)
2059 printk(KERN_ERR
"tty driver %s lacks a write_room method.\n",
2061 ld
= tty_ldisc_ref_wait(tty
);
2062 if (!ld
->ops
->write
)
2065 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
2066 tty_ldisc_deref(ld
);
2070 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
2071 size_t count
, loff_t
*ppos
)
2073 struct file
*p
= NULL
;
2075 spin_lock(&redirect_lock
);
2080 spin_unlock(&redirect_lock
);
2084 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
2088 return tty_write(file
, buf
, count
, ppos
);
2091 void tty_port_init(struct tty_port
*port
)
2093 memset(port
, 0, sizeof(*port
));
2094 init_waitqueue_head(&port
->open_wait
);
2095 init_waitqueue_head(&port
->close_wait
);
2096 mutex_init(&port
->mutex
);
2098 EXPORT_SYMBOL(tty_port_init
);
2100 int tty_port_alloc_xmit_buf(struct tty_port
*port
)
2102 /* We may sleep in get_zeroed_page() */
2103 mutex_lock(&port
->mutex
);
2104 if (port
->xmit_buf
== NULL
)
2105 port
->xmit_buf
= (unsigned char *)get_zeroed_page(GFP_KERNEL
);
2106 mutex_unlock(&port
->mutex
);
2107 if (port
->xmit_buf
== NULL
)
2111 EXPORT_SYMBOL(tty_port_alloc_xmit_buf
);
2113 void tty_port_free_xmit_buf(struct tty_port
*port
)
2115 mutex_lock(&port
->mutex
);
2116 if (port
->xmit_buf
!= NULL
) {
2117 free_page((unsigned long)port
->xmit_buf
);
2118 port
->xmit_buf
= NULL
;
2120 mutex_unlock(&port
->mutex
);
2122 EXPORT_SYMBOL(tty_port_free_xmit_buf
);
2125 static char ptychar
[] = "pqrstuvwxyzabcde";
2128 * pty_line_name - generate name for a pty
2129 * @driver: the tty driver in use
2130 * @index: the minor number
2131 * @p: output buffer of at least 6 bytes
2133 * Generate a name from a driver reference and write it to the output
2138 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
2140 int i
= index
+ driver
->name_base
;
2141 /* ->name is initialized to "ttyp", but "tty" is expected */
2142 sprintf(p
, "%s%c%x",
2143 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
2144 ptychar
[i
>> 4 & 0xf], i
& 0xf);
2148 * pty_line_name - generate name for a tty
2149 * @driver: the tty driver in use
2150 * @index: the minor number
2151 * @p: output buffer of at least 7 bytes
2153 * Generate a name from a driver reference and write it to the output
2158 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
2160 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
2164 * init_dev - initialise a tty device
2165 * @driver: tty driver we are opening a device on
2166 * @idx: device index
2167 * @tty: returned tty structure
2169 * Prepare a tty device. This may not be a "new" clean device but
2170 * could also be an active device. The pty drivers require special
2171 * handling because of this.
2174 * The function is called under the tty_mutex, which
2175 * protects us from the tty struct or driver itself going away.
2177 * On exit the tty device has the line discipline attached and
2178 * a reference count of 1. If a pair was created for pty/tty use
2179 * and the other was a pty master then it too has a reference count of 1.
2181 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
2182 * failed open. The new code protects the open with a mutex, so it's
2183 * really quite straightforward. The mutex locking can probably be
2184 * relaxed for the (most common) case of reopening a tty.
2187 static int init_dev(struct tty_driver
*driver
, int idx
,
2188 struct tty_struct
**ret_tty
)
2190 struct tty_struct
*tty
, *o_tty
;
2191 struct ktermios
*tp
, **tp_loc
, *o_tp
, **o_tp_loc
;
2192 struct ktermios
*ltp
, **ltp_loc
, *o_ltp
, **o_ltp_loc
;
2194 struct tty_ldisc
*ld
;
2196 /* check whether we're reopening an existing tty */
2197 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
2198 tty
= devpts_get_tty(idx
);
2200 * If we don't have a tty here on a slave open, it's because
2201 * the master already started the close process and there's
2202 * no relation between devpts file and tty anymore.
2204 if (!tty
&& driver
->subtype
== PTY_TYPE_SLAVE
) {
2209 * It's safe from now on because init_dev() is called with
2210 * tty_mutex held and release_dev() won't change tty->count
2211 * or tty->flags without having to grab tty_mutex
2213 if (tty
&& driver
->subtype
== PTY_TYPE_MASTER
)
2216 tty
= driver
->ttys
[idx
];
2218 if (tty
) goto fast_track
;
2221 * First time open is complex, especially for PTY devices.
2222 * This code guarantees that either everything succeeds and the
2223 * TTY is ready for operation, or else the table slots are vacated
2224 * and the allocated memory released. (Except that the termios
2225 * and locked termios may be retained.)
2228 if (!try_module_get(driver
->owner
)) {
2237 tty
= alloc_tty_struct();
2240 initialize_tty_struct(tty
);
2241 tty
->driver
= driver
;
2242 tty
->ops
= driver
->ops
;
2244 tty_line_name(driver
, idx
, tty
->name
);
2246 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
2247 tp_loc
= &tty
->termios
;
2248 ltp_loc
= &tty
->termios_locked
;
2250 tp_loc
= &driver
->termios
[idx
];
2251 ltp_loc
= &driver
->termios_locked
[idx
];
2255 tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
2258 *tp
= driver
->init_termios
;
2262 ltp
= kzalloc(sizeof(struct ktermios
), GFP_KERNEL
);
2267 if (driver
->type
== TTY_DRIVER_TYPE_PTY
) {
2268 o_tty
= alloc_tty_struct();
2271 initialize_tty_struct(o_tty
);
2272 o_tty
->driver
= driver
->other
;
2273 o_tty
->ops
= driver
->ops
;
2275 tty_line_name(driver
->other
, idx
, o_tty
->name
);
2277 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
2278 o_tp_loc
= &o_tty
->termios
;
2279 o_ltp_loc
= &o_tty
->termios_locked
;
2281 o_tp_loc
= &driver
->other
->termios
[idx
];
2282 o_ltp_loc
= &driver
->other
->termios_locked
[idx
];
2286 o_tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
2289 *o_tp
= driver
->other
->init_termios
;
2293 o_ltp
= kzalloc(sizeof(struct ktermios
), GFP_KERNEL
);
2299 * Everything allocated ... set up the o_tty structure.
2301 if (!(driver
->other
->flags
& TTY_DRIVER_DEVPTS_MEM
))
2302 driver
->other
->ttys
[idx
] = o_tty
;
2307 o_tty
->termios
= *o_tp_loc
;
2308 o_tty
->termios_locked
= *o_ltp_loc
;
2309 driver
->other
->refcount
++;
2310 if (driver
->subtype
== PTY_TYPE_MASTER
)
2313 /* Establish the links in both directions */
2319 * All structures have been allocated, so now we install them.
2320 * Failures after this point use release_tty to clean up, so
2321 * there's no need to null out the local pointers.
2323 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
))
2324 driver
->ttys
[idx
] = tty
;
2330 tty
->termios
= *tp_loc
;
2331 tty
->termios_locked
= *ltp_loc
;
2332 /* Compatibility until drivers always set this */
2333 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
2334 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
2339 * Structures all installed ... call the ldisc open routines.
2340 * If we fail here just call release_tty to clean up. No need
2341 * to decrement the use counts, as release_tty doesn't care.
2346 if (ld
->ops
->open
) {
2347 retval
= (ld
->ops
->open
)(tty
);
2349 goto release_mem_out
;
2351 if (o_tty
&& o_tty
->ldisc
.ops
->open
) {
2352 retval
= (o_tty
->ldisc
.ops
->open
)(o_tty
);
2355 (ld
->ops
->close
)(tty
);
2356 goto release_mem_out
;
2358 tty_ldisc_enable(o_tty
);
2360 tty_ldisc_enable(tty
);
2364 * This fast open can be used if the tty is already open.
2365 * No memory is allocated, and the only failures are from
2366 * attempting to open a closing tty or attempting multiple
2367 * opens on a pty master.
2370 if (test_bit(TTY_CLOSING
, &tty
->flags
)) {
2374 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2375 driver
->subtype
== PTY_TYPE_MASTER
) {
2377 * special case for PTY masters: only one open permitted,
2378 * and the slave side open count is incremented as well.
2387 tty
->driver
= driver
; /* N.B. why do this every time?? */
2390 if (!test_bit(TTY_LDISC
, &tty
->flags
))
2391 printk(KERN_ERR
"init_dev but no ldisc\n");
2395 /* All paths come through here to release the mutex */
2399 /* Release locally allocated memory ... nothing placed in slots */
2403 free_tty_struct(o_tty
);
2406 free_tty_struct(tty
);
2409 module_put(driver
->owner
);
2413 /* call the tty release_tty routine to clean out this slot */
2415 if (printk_ratelimit())
2416 printk(KERN_INFO
"init_dev: ldisc open failed, "
2417 "clearing slot %d\n", idx
);
2418 release_tty(tty
, idx
);
2423 * release_one_tty - release tty structure memory
2425 * Releases memory associated with a tty structure, and clears out the
2426 * driver table slots. This function is called when a device is no longer
2427 * in use. It also gets called when setup of a device fails.
2430 * tty_mutex - sometimes only
2431 * takes the file list lock internally when working on the list
2432 * of ttys that the driver keeps.
2433 * FIXME: should we require tty_mutex is held here ??
2435 static void release_one_tty(struct tty_struct
*tty
, int idx
)
2437 int devpts
= tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
;
2438 struct ktermios
*tp
;
2441 tty
->driver
->ttys
[idx
] = NULL
;
2443 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
) {
2446 tty
->driver
->termios
[idx
] = NULL
;
2449 tp
= tty
->termios_locked
;
2451 tty
->driver
->termios_locked
[idx
] = NULL
;
2457 tty
->driver
->refcount
--;
2460 list_del_init(&tty
->tty_files
);
2463 free_tty_struct(tty
);
2467 * release_tty - release tty structure memory
2469 * Release both @tty and a possible linked partner (think pty pair),
2470 * and decrement the refcount of the backing module.
2473 * tty_mutex - sometimes only
2474 * takes the file list lock internally when working on the list
2475 * of ttys that the driver keeps.
2476 * FIXME: should we require tty_mutex is held here ??
2478 static void release_tty(struct tty_struct
*tty
, int idx
)
2480 struct tty_driver
*driver
= tty
->driver
;
2483 release_one_tty(tty
->link
, idx
);
2484 release_one_tty(tty
, idx
);
2485 module_put(driver
->owner
);
2489 * Even releasing the tty structures is a tricky business.. We have
2490 * to be very careful that the structures are all released at the
2491 * same time, as interrupts might otherwise get the wrong pointers.
2493 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
2494 * lead to double frees or releasing memory still in use.
2496 static void release_dev(struct file
*filp
)
2498 struct tty_struct
*tty
, *o_tty
;
2499 struct tty_ldisc ld
;
2500 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
2504 unsigned long flags
;
2506 tty
= (struct tty_struct
*)filp
->private_data
;
2507 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
,
2511 check_tty_count(tty
, "release_dev");
2513 tty_fasync(-1, filp
, 0);
2516 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2517 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
2518 devpts
= (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) != 0;
2521 #ifdef TTY_PARANOIA_CHECK
2522 if (idx
< 0 || idx
>= tty
->driver
->num
) {
2523 printk(KERN_DEBUG
"release_dev: bad idx when trying to "
2524 "free (%s)\n", tty
->name
);
2527 if (!(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2528 if (tty
!= tty
->driver
->ttys
[idx
]) {
2529 printk(KERN_DEBUG
"release_dev: driver.table[%d] not tty "
2530 "for (%s)\n", idx
, tty
->name
);
2533 if (tty
->termios
!= tty
->driver
->termios
[idx
]) {
2534 printk(KERN_DEBUG
"release_dev: driver.termios[%d] not termios "
2539 if (tty
->termios_locked
!= tty
->driver
->termios_locked
[idx
]) {
2540 printk(KERN_DEBUG
"release_dev: driver.termios_locked[%d] not "
2541 "termios_locked for (%s)\n",
2548 #ifdef TTY_DEBUG_HANGUP
2549 printk(KERN_DEBUG
"release_dev of %s (tty count=%d)...",
2550 tty_name(tty
, buf
), tty
->count
);
2553 #ifdef TTY_PARANOIA_CHECK
2554 if (tty
->driver
->other
&&
2555 !(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2556 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
2557 printk(KERN_DEBUG
"release_dev: other->table[%d] "
2558 "not o_tty for (%s)\n",
2562 if (o_tty
->termios
!= tty
->driver
->other
->termios
[idx
]) {
2563 printk(KERN_DEBUG
"release_dev: other->termios[%d] "
2564 "not o_termios for (%s)\n",
2568 if (o_tty
->termios_locked
!=
2569 tty
->driver
->other
->termios_locked
[idx
]) {
2570 printk(KERN_DEBUG
"release_dev: other->termios_locked["
2571 "%d] not o_termios_locked for (%s)\n",
2575 if (o_tty
->link
!= tty
) {
2576 printk(KERN_DEBUG
"release_dev: bad pty pointers\n");
2581 if (tty
->ops
->close
)
2582 tty
->ops
->close(tty
, filp
);
2585 * Sanity check: if tty->count is going to zero, there shouldn't be
2586 * any waiters on tty->read_wait or tty->write_wait. We test the
2587 * wait queues and kick everyone out _before_ actually starting to
2588 * close. This ensures that we won't block while releasing the tty
2591 * The test for the o_tty closing is necessary, since the master and
2592 * slave sides may close in any order. If the slave side closes out
2593 * first, its count will be one, since the master side holds an open.
2594 * Thus this test wouldn't be triggered at the time the slave closes,
2597 * Note that it's possible for the tty to be opened again while we're
2598 * flushing out waiters. By recalculating the closing flags before
2599 * each iteration we avoid any problems.
2602 /* Guard against races with tty->count changes elsewhere and
2603 opens on /dev/tty */
2605 mutex_lock(&tty_mutex
);
2606 tty_closing
= tty
->count
<= 1;
2607 o_tty_closing
= o_tty
&&
2608 (o_tty
->count
<= (pty_master
? 1 : 0));
2612 if (waitqueue_active(&tty
->read_wait
)) {
2613 wake_up(&tty
->read_wait
);
2616 if (waitqueue_active(&tty
->write_wait
)) {
2617 wake_up(&tty
->write_wait
);
2621 if (o_tty_closing
) {
2622 if (waitqueue_active(&o_tty
->read_wait
)) {
2623 wake_up(&o_tty
->read_wait
);
2626 if (waitqueue_active(&o_tty
->write_wait
)) {
2627 wake_up(&o_tty
->write_wait
);
2634 printk(KERN_WARNING
"release_dev: %s: read/write wait queue "
2635 "active!\n", tty_name(tty
, buf
));
2636 mutex_unlock(&tty_mutex
);
2641 * The closing flags are now consistent with the open counts on
2642 * both sides, and we've completed the last operation that could
2643 * block, so it's safe to proceed with closing.
2646 if (--o_tty
->count
< 0) {
2647 printk(KERN_WARNING
"release_dev: bad pty slave count "
2649 o_tty
->count
, tty_name(o_tty
, buf
));
2653 if (--tty
->count
< 0) {
2654 printk(KERN_WARNING
"release_dev: bad tty->count (%d) for %s\n",
2655 tty
->count
, tty_name(tty
, buf
));
2660 * We've decremented tty->count, so we need to remove this file
2661 * descriptor off the tty->tty_files list; this serves two
2663 * - check_tty_count sees the correct number of file descriptors
2664 * associated with this tty.
2665 * - do_tty_hangup no longer sees this file descriptor as
2666 * something that needs to be handled for hangups.
2669 filp
->private_data
= NULL
;
2672 * Perform some housekeeping before deciding whether to return.
2674 * Set the TTY_CLOSING flag if this was the last open. In the
2675 * case of a pty we may have to wait around for the other side
2676 * to close, and TTY_CLOSING makes sure we can't be reopened.
2679 set_bit(TTY_CLOSING
, &tty
->flags
);
2681 set_bit(TTY_CLOSING
, &o_tty
->flags
);
2684 * If _either_ side is closing, make sure there aren't any
2685 * processes that still think tty or o_tty is their controlling
2688 if (tty_closing
|| o_tty_closing
) {
2689 read_lock(&tasklist_lock
);
2690 session_clear_tty(tty
->session
);
2692 session_clear_tty(o_tty
->session
);
2693 read_unlock(&tasklist_lock
);
2696 mutex_unlock(&tty_mutex
);
2698 /* check whether both sides are closing ... */
2699 if (!tty_closing
|| (o_tty
&& !o_tty_closing
))
2702 #ifdef TTY_DEBUG_HANGUP
2703 printk(KERN_DEBUG
"freeing tty structure...");
2706 * Prevent flush_to_ldisc() from rescheduling the work for later. Then
2707 * kill any delayed work. As this is the final close it does not
2708 * race with the set_ldisc code path.
2710 clear_bit(TTY_LDISC
, &tty
->flags
);
2711 cancel_delayed_work(&tty
->buf
.work
);
2714 * Wait for ->hangup_work and ->buf.work handlers to terminate
2717 flush_scheduled_work();
2720 * Wait for any short term users (we know they are just driver
2721 * side waiters as the file is closing so user count on the file
2724 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
2725 while (tty
->ldisc
.refcount
) {
2726 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
2727 wait_event(tty_ldisc_wait
, tty
->ldisc
.refcount
== 0);
2728 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
2730 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
2732 * Shutdown the current line discipline, and reset it to N_TTY.
2734 * FIXME: this MUST get fixed for the new reflocking
2736 if (tty
->ldisc
.ops
->close
)
2737 (tty
->ldisc
.ops
->close
)(tty
);
2738 tty_ldisc_put(tty
->ldisc
.ops
);
2741 * Switch the line discipline back
2743 WARN_ON(tty_ldisc_get(N_TTY
, &ld
));
2744 tty_ldisc_assign(tty
, &ld
);
2745 tty_set_termios_ldisc(tty
, N_TTY
);
2747 /* FIXME: could o_tty be in setldisc here ? */
2748 clear_bit(TTY_LDISC
, &o_tty
->flags
);
2749 if (o_tty
->ldisc
.ops
->close
)
2750 (o_tty
->ldisc
.ops
->close
)(o_tty
);
2751 tty_ldisc_put(o_tty
->ldisc
.ops
);
2752 WARN_ON(tty_ldisc_get(N_TTY
, &ld
));
2753 tty_ldisc_assign(o_tty
, &ld
);
2754 tty_set_termios_ldisc(o_tty
, N_TTY
);
2757 * The release_tty function takes care of the details of clearing
2758 * the slots and preserving the termios structure.
2760 release_tty(tty
, idx
);
2762 /* Make this pty number available for reallocation */
2764 devpts_kill_index(idx
);
2768 * tty_open - open a tty device
2769 * @inode: inode of device file
2770 * @filp: file pointer to tty
2772 * tty_open and tty_release keep up the tty count that contains the
2773 * number of opens done on a tty. We cannot use the inode-count, as
2774 * different inodes might point to the same tty.
2776 * Open-counting is needed for pty masters, as well as for keeping
2777 * track of serial lines: DTR is dropped when the last close happens.
2778 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2780 * The termios state of a pty is reset on first open so that
2781 * settings don't persist across reuse.
2783 * Locking: tty_mutex protects tty, get_tty_driver and init_dev work.
2784 * tty->count should protect the rest.
2785 * ->siglock protects ->signal/->sighand
2788 static int __tty_open(struct inode
*inode
, struct file
*filp
)
2790 struct tty_struct
*tty
;
2792 struct tty_driver
*driver
;
2794 dev_t device
= inode
->i_rdev
;
2795 unsigned short saved_flags
= filp
->f_flags
;
2797 nonseekable_open(inode
, filp
);
2800 noctty
= filp
->f_flags
& O_NOCTTY
;
2804 mutex_lock(&tty_mutex
);
2806 if (device
== MKDEV(TTYAUX_MAJOR
, 0)) {
2807 tty
= get_current_tty();
2809 mutex_unlock(&tty_mutex
);
2812 driver
= tty
->driver
;
2814 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
2819 if (device
== MKDEV(TTY_MAJOR
, 0)) {
2820 extern struct tty_driver
*console_driver
;
2821 driver
= console_driver
;
2827 if (device
== MKDEV(TTYAUX_MAJOR
, 1)) {
2828 driver
= console_device(&index
);
2830 /* Don't let /dev/console block */
2831 filp
->f_flags
|= O_NONBLOCK
;
2835 mutex_unlock(&tty_mutex
);
2839 driver
= get_tty_driver(device
, &index
);
2841 mutex_unlock(&tty_mutex
);
2845 retval
= init_dev(driver
, index
, &tty
);
2846 mutex_unlock(&tty_mutex
);
2850 filp
->private_data
= tty
;
2851 file_move(filp
, &tty
->tty_files
);
2852 check_tty_count(tty
, "tty_open");
2853 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2854 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2856 #ifdef TTY_DEBUG_HANGUP
2857 printk(KERN_DEBUG
"opening %s...", tty
->name
);
2861 retval
= tty
->ops
->open(tty
, filp
);
2865 filp
->f_flags
= saved_flags
;
2867 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) &&
2868 !capable(CAP_SYS_ADMIN
))
2872 #ifdef TTY_DEBUG_HANGUP
2873 printk(KERN_DEBUG
"error %d in opening %s...", retval
,
2877 if (retval
!= -ERESTARTSYS
)
2879 if (signal_pending(current
))
2883 * Need to reset f_op in case a hangup happened.
2885 if (filp
->f_op
== &hung_up_tty_fops
)
2886 filp
->f_op
= &tty_fops
;
2890 mutex_lock(&tty_mutex
);
2891 spin_lock_irq(¤t
->sighand
->siglock
);
2893 current
->signal
->leader
&&
2894 !current
->signal
->tty
&&
2895 tty
->session
== NULL
)
2896 __proc_set_tty(current
, tty
);
2897 spin_unlock_irq(¤t
->sighand
->siglock
);
2898 mutex_unlock(&tty_mutex
);
2902 /* BKL pushdown: scary code avoidance wrapper */
2903 static int tty_open(struct inode
*inode
, struct file
*filp
)
2908 ret
= __tty_open(inode
, filp
);
2915 #ifdef CONFIG_UNIX98_PTYS
2917 * ptmx_open - open a unix 98 pty master
2918 * @inode: inode of device file
2919 * @filp: file pointer to tty
2921 * Allocate a unix98 pty master device from the ptmx driver.
2923 * Locking: tty_mutex protects theinit_dev work. tty->count should
2925 * allocated_ptys_lock handles the list of free pty numbers
2928 static int __ptmx_open(struct inode
*inode
, struct file
*filp
)
2930 struct tty_struct
*tty
;
2934 nonseekable_open(inode
, filp
);
2936 /* find a device that is not in use. */
2937 index
= devpts_new_index();
2941 mutex_lock(&tty_mutex
);
2942 retval
= init_dev(ptm_driver
, index
, &tty
);
2943 mutex_unlock(&tty_mutex
);
2948 set_bit(TTY_PTY_LOCK
, &tty
->flags
); /* LOCK THE SLAVE */
2949 filp
->private_data
= tty
;
2950 file_move(filp
, &tty
->tty_files
);
2952 retval
= devpts_pty_new(tty
->link
);
2956 check_tty_count(tty
, "ptmx_open");
2957 retval
= ptm_driver
->ops
->open(tty
, filp
);
2964 devpts_kill_index(index
);
2968 static int ptmx_open(struct inode
*inode
, struct file
*filp
)
2973 ret
= __ptmx_open(inode
, filp
);
2980 * tty_release - vfs callback for close
2981 * @inode: inode of tty
2982 * @filp: file pointer for handle to tty
2984 * Called the last time each file handle is closed that references
2985 * this tty. There may however be several such references.
2988 * Takes bkl. See release_dev
2991 static int tty_release(struct inode
*inode
, struct file
*filp
)
3000 * tty_poll - check tty status
3001 * @filp: file being polled
3002 * @wait: poll wait structures to update
3004 * Call the line discipline polling method to obtain the poll
3005 * status of the device.
3007 * Locking: locks called line discipline but ldisc poll method
3008 * may be re-entered freely by other callers.
3011 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
3013 struct tty_struct
*tty
;
3014 struct tty_ldisc
*ld
;
3017 tty
= (struct tty_struct
*)filp
->private_data
;
3018 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
3021 ld
= tty_ldisc_ref_wait(tty
);
3023 ret
= (ld
->ops
->poll
)(tty
, filp
, wait
);
3024 tty_ldisc_deref(ld
);
3028 static int tty_fasync(int fd
, struct file
*filp
, int on
)
3030 struct tty_struct
*tty
;
3031 unsigned long flags
;
3035 tty
= (struct tty_struct
*)filp
->private_data
;
3036 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
3039 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
3046 if (!waitqueue_active(&tty
->read_wait
))
3047 tty
->minimum_to_wake
= 1;
3048 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
3051 type
= PIDTYPE_PGID
;
3053 pid
= task_pid(current
);
3056 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
3057 retval
= __f_setown(filp
, pid
, type
, 0);
3061 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
3062 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
3071 * tiocsti - fake input character
3072 * @tty: tty to fake input into
3073 * @p: pointer to character
3075 * Fake input to a tty device. Does the necessary locking and
3078 * FIXME: does not honour flow control ??
3081 * Called functions take tty_ldisc_lock
3082 * current->signal->tty check is safe without locks
3084 * FIXME: may race normal receive processing
3087 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
3090 struct tty_ldisc
*ld
;
3092 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
3094 if (get_user(ch
, p
))
3096 ld
= tty_ldisc_ref_wait(tty
);
3097 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
3098 tty_ldisc_deref(ld
);
3103 * tiocgwinsz - implement window query ioctl
3105 * @arg: user buffer for result
3107 * Copies the kernel idea of the window size into the user buffer.
3109 * Locking: tty->termios_mutex is taken to ensure the winsize data
3113 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
3117 mutex_lock(&tty
->termios_mutex
);
3118 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
3119 mutex_unlock(&tty
->termios_mutex
);
3121 return err
? -EFAULT
: 0;
3125 * tiocswinsz - implement window size set ioctl
3127 * @arg: user buffer for result
3129 * Copies the user idea of the window size to the kernel. Traditionally
3130 * this is just advisory information but for the Linux console it
3131 * actually has driver level meaning and triggers a VC resize.
3134 * Called function use the console_sem is used to ensure we do
3135 * not try and resize the console twice at once.
3136 * The tty->termios_mutex is used to ensure we don't double
3137 * resize and get confused. Lock order - tty->termios_mutex before
3141 static int tiocswinsz(struct tty_struct
*tty
, struct tty_struct
*real_tty
,
3142 struct winsize __user
*arg
)
3144 struct winsize tmp_ws
;
3145 struct pid
*pgrp
, *rpgrp
;
3146 unsigned long flags
;
3148 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
3151 mutex_lock(&tty
->termios_mutex
);
3152 if (!memcmp(&tmp_ws
, &tty
->winsize
, sizeof(*arg
)))
3156 if (tty
->driver
->type
== TTY_DRIVER_TYPE_CONSOLE
) {
3157 if (vc_lock_resize(tty
->driver_data
, tmp_ws
.ws_col
,
3159 mutex_unlock(&tty
->termios_mutex
);
3164 /* Get the PID values and reference them so we can
3165 avoid holding the tty ctrl lock while sending signals */
3166 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
3167 pgrp
= get_pid(tty
->pgrp
);
3168 rpgrp
= get_pid(real_tty
->pgrp
);
3169 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
3172 kill_pgrp(pgrp
, SIGWINCH
, 1);
3173 if (rpgrp
!= pgrp
&& rpgrp
)
3174 kill_pgrp(rpgrp
, SIGWINCH
, 1);
3179 tty
->winsize
= tmp_ws
;
3180 real_tty
->winsize
= tmp_ws
;
3182 mutex_unlock(&tty
->termios_mutex
);
3187 * tioccons - allow admin to move logical console
3188 * @file: the file to become console
3190 * Allow the adminstrator to move the redirected console device
3192 * Locking: uses redirect_lock to guard the redirect information
3195 static int tioccons(struct file
*file
)
3197 if (!capable(CAP_SYS_ADMIN
))
3199 if (file
->f_op
->write
== redirected_tty_write
) {
3201 spin_lock(&redirect_lock
);
3204 spin_unlock(&redirect_lock
);
3209 spin_lock(&redirect_lock
);
3211 spin_unlock(&redirect_lock
);
3216 spin_unlock(&redirect_lock
);
3221 * fionbio - non blocking ioctl
3222 * @file: file to set blocking value
3223 * @p: user parameter
3225 * Historical tty interfaces had a blocking control ioctl before
3226 * the generic functionality existed. This piece of history is preserved
3227 * in the expected tty API of posix OS's.
3229 * Locking: none, the open fle handle ensures it won't go away.
3232 static int fionbio(struct file
*file
, int __user
*p
)
3236 if (get_user(nonblock
, p
))
3239 /* file->f_flags is still BKL protected in the fs layer - vomit */
3242 file
->f_flags
|= O_NONBLOCK
;
3244 file
->f_flags
&= ~O_NONBLOCK
;
3250 * tiocsctty - set controlling tty
3251 * @tty: tty structure
3252 * @arg: user argument
3254 * This ioctl is used to manage job control. It permits a session
3255 * leader to set this tty as the controlling tty for the session.
3258 * Takes tty_mutex() to protect tty instance
3259 * Takes tasklist_lock internally to walk sessions
3260 * Takes ->siglock() when updating signal->tty
3263 static int tiocsctty(struct tty_struct
*tty
, int arg
)
3266 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
3269 mutex_lock(&tty_mutex
);
3271 * The process must be a session leader and
3272 * not have a controlling tty already.
3274 if (!current
->signal
->leader
|| current
->signal
->tty
) {
3281 * This tty is already the controlling
3282 * tty for another session group!
3284 if (arg
== 1 && capable(CAP_SYS_ADMIN
)) {
3288 read_lock(&tasklist_lock
);
3289 session_clear_tty(tty
->session
);
3290 read_unlock(&tasklist_lock
);
3296 proc_set_tty(current
, tty
);
3298 mutex_unlock(&tty_mutex
);
3303 * tty_get_pgrp - return a ref counted pgrp pid
3306 * Returns a refcounted instance of the pid struct for the process
3307 * group controlling the tty.
3310 struct pid
*tty_get_pgrp(struct tty_struct
*tty
)
3312 unsigned long flags
;
3315 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
3316 pgrp
= get_pid(tty
->pgrp
);
3317 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
3321 EXPORT_SYMBOL_GPL(tty_get_pgrp
);
3324 * tiocgpgrp - get process group
3325 * @tty: tty passed by user
3326 * @real_tty: tty side of the tty pased by the user if a pty else the tty
3329 * Obtain the process group of the tty. If there is no process group
3332 * Locking: none. Reference to current->signal->tty is safe.
3335 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3340 * (tty == real_tty) is a cheap way of
3341 * testing if the tty is NOT a master pty.
3343 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
3345 pid
= tty_get_pgrp(real_tty
);
3346 ret
= put_user(pid_vnr(pid
), p
);
3352 * tiocspgrp - attempt to set process group
3353 * @tty: tty passed by user
3354 * @real_tty: tty side device matching tty passed by user
3357 * Set the process group of the tty to the session passed. Only
3358 * permitted where the tty session is our session.
3360 * Locking: RCU, ctrl lock
3363 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3367 int retval
= tty_check_change(real_tty
);
3368 unsigned long flags
;
3374 if (!current
->signal
->tty
||
3375 (current
->signal
->tty
!= real_tty
) ||
3376 (real_tty
->session
!= task_session(current
)))
3378 if (get_user(pgrp_nr
, p
))
3383 pgrp
= find_vpid(pgrp_nr
);
3388 if (session_of_pgrp(pgrp
) != task_session(current
))
3391 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
3392 put_pid(real_tty
->pgrp
);
3393 real_tty
->pgrp
= get_pid(pgrp
);
3394 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
3401 * tiocgsid - get session id
3402 * @tty: tty passed by user
3403 * @real_tty: tty side of the tty pased by the user if a pty else the tty
3404 * @p: pointer to returned session id
3406 * Obtain the session id of the tty. If there is no session
3409 * Locking: none. Reference to current->signal->tty is safe.
3412 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3415 * (tty == real_tty) is a cheap way of
3416 * testing if the tty is NOT a master pty.
3418 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
3420 if (!real_tty
->session
)
3422 return put_user(pid_vnr(real_tty
->session
), p
);
3426 * tiocsetd - set line discipline
3428 * @p: pointer to user data
3430 * Set the line discipline according to user request.
3432 * Locking: see tty_set_ldisc, this function is just a helper
3435 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
3440 if (get_user(ldisc
, p
))
3444 ret
= tty_set_ldisc(tty
, ldisc
);
3451 * send_break - performed time break
3452 * @tty: device to break on
3453 * @duration: timeout in mS
3455 * Perform a timed break on hardware that lacks its own driver level
3456 * timed break functionality.
3459 * atomic_write_lock serializes
3463 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
3465 if (tty_write_lock(tty
, 0) < 0)
3467 tty
->ops
->break_ctl(tty
, -1);
3468 if (!signal_pending(current
))
3469 msleep_interruptible(duration
);
3470 tty
->ops
->break_ctl(tty
, 0);
3471 tty_write_unlock(tty
);
3472 if (signal_pending(current
))
3478 * tty_tiocmget - get modem status
3480 * @file: user file pointer
3481 * @p: pointer to result
3483 * Obtain the modem status bits from the tty driver if the feature
3484 * is supported. Return -EINVAL if it is not available.
3486 * Locking: none (up to the driver)
3489 static int tty_tiocmget(struct tty_struct
*tty
, struct file
*file
, int __user
*p
)
3491 int retval
= -EINVAL
;
3493 if (tty
->ops
->tiocmget
) {
3494 retval
= tty
->ops
->tiocmget(tty
, file
);
3497 retval
= put_user(retval
, p
);
3503 * tty_tiocmset - set modem status
3505 * @file: user file pointer
3506 * @cmd: command - clear bits, set bits or set all
3507 * @p: pointer to desired bits
3509 * Set the modem status bits from the tty driver if the feature
3510 * is supported. Return -EINVAL if it is not available.
3512 * Locking: none (up to the driver)
3515 static int tty_tiocmset(struct tty_struct
*tty
, struct file
*file
, unsigned int cmd
,
3518 int retval
= -EINVAL
;
3520 if (tty
->ops
->tiocmset
) {
3521 unsigned int set
, clear
, val
;
3523 retval
= get_user(val
, p
);
3541 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
3542 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
3544 retval
= tty
->ops
->tiocmset(tty
, file
, set
, clear
);
3550 * Split this up, as gcc can choke on it otherwise..
3552 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
3554 struct tty_struct
*tty
, *real_tty
;
3555 void __user
*p
= (void __user
*)arg
;
3557 struct tty_ldisc
*ld
;
3558 struct inode
*inode
= file
->f_dentry
->d_inode
;
3560 tty
= (struct tty_struct
*)file
->private_data
;
3561 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
3565 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
3566 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
3567 real_tty
= tty
->link
;
3570 * Break handling by driver
3575 if (!tty
->ops
->break_ctl
) {
3579 if (tty
->ops
->ioctl
)
3580 retval
= tty
->ops
->ioctl(tty
, file
, cmd
, arg
);
3581 if (retval
!= -EINVAL
&& retval
!= -ENOIOCTLCMD
)
3582 printk(KERN_WARNING
"tty: driver %s needs updating to use break_ctl\n", tty
->driver
->name
);
3585 /* These two ioctl's always return success; even if */
3586 /* the driver doesn't support them. */
3589 if (!tty
->ops
->ioctl
)
3591 retval
= tty
->ops
->ioctl(tty
, file
, cmd
, arg
);
3592 if (retval
!= -EINVAL
&& retval
!= -ENOIOCTLCMD
)
3593 printk(KERN_WARNING
"tty: driver %s needs updating to use break_ctl\n", tty
->driver
->name
);
3594 if (retval
== -ENOIOCTLCMD
)
3601 * Factor out some common prep work
3609 retval
= tty_check_change(tty
);
3612 if (cmd
!= TIOCCBRK
) {
3613 tty_wait_until_sent(tty
, 0);
3614 if (signal_pending(current
))
3622 return tiocsti(tty
, p
);
3624 return tiocgwinsz(tty
, p
);
3626 return tiocswinsz(tty
, real_tty
, p
);
3628 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
3630 return fionbio(file
, p
);
3632 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
3635 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
3638 if (current
->signal
->tty
!= tty
)
3643 return tiocsctty(tty
, arg
);
3645 return tiocgpgrp(tty
, real_tty
, p
);
3647 return tiocspgrp(tty
, real_tty
, p
);
3649 return tiocgsid(tty
, real_tty
, p
);
3651 return put_user(tty
->ldisc
.ops
->num
, (int __user
*)p
);
3653 return tiocsetd(tty
, p
);
3656 return tioclinux(tty
, arg
);
3661 case TIOCSBRK
: /* Turn break on, unconditionally */
3662 if (tty
->ops
->break_ctl
)
3663 tty
->ops
->break_ctl(tty
, -1);
3666 case TIOCCBRK
: /* Turn break off, unconditionally */
3667 if (tty
->ops
->break_ctl
)
3668 tty
->ops
->break_ctl(tty
, 0);
3670 case TCSBRK
: /* SVID version: non-zero arg --> no break */
3671 /* non-zero arg means wait for all output data
3672 * to be sent (performed above) but don't send break.
3673 * This is used by the tcdrain() termios function.
3676 return send_break(tty
, 250);
3678 case TCSBRKP
: /* support for POSIX tcsendbreak() */
3679 return send_break(tty
, arg
? arg
*100 : 250);
3682 return tty_tiocmget(tty
, file
, p
);
3686 return tty_tiocmset(tty
, file
, cmd
, p
);
3691 /* flush tty buffer and allow ldisc to process ioctl */
3692 tty_buffer_flush(tty
);
3697 if (tty
->ops
->ioctl
) {
3698 retval
= (tty
->ops
->ioctl
)(tty
, file
, cmd
, arg
);
3699 if (retval
!= -ENOIOCTLCMD
)
3702 ld
= tty_ldisc_ref_wait(tty
);
3704 if (ld
->ops
->ioctl
) {
3705 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
3706 if (retval
== -ENOIOCTLCMD
)
3709 tty_ldisc_deref(ld
);
3713 #ifdef CONFIG_COMPAT
3714 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
3717 struct inode
*inode
= file
->f_dentry
->d_inode
;
3718 struct tty_struct
*tty
= file
->private_data
;
3719 struct tty_ldisc
*ld
;
3720 int retval
= -ENOIOCTLCMD
;
3722 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
3725 if (tty
->ops
->compat_ioctl
) {
3726 retval
= (tty
->ops
->compat_ioctl
)(tty
, file
, cmd
, arg
);
3727 if (retval
!= -ENOIOCTLCMD
)
3731 ld
= tty_ldisc_ref_wait(tty
);
3732 if (ld
->ops
->compat_ioctl
)
3733 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
3734 tty_ldisc_deref(ld
);
3741 * This implements the "Secure Attention Key" --- the idea is to
3742 * prevent trojan horses by killing all processes associated with this
3743 * tty when the user hits the "Secure Attention Key". Required for
3744 * super-paranoid applications --- see the Orange Book for more details.
3746 * This code could be nicer; ideally it should send a HUP, wait a few
3747 * seconds, then send a INT, and then a KILL signal. But you then
3748 * have to coordinate with the init process, since all processes associated
3749 * with the current tty must be dead before the new getty is allowed
3752 * Now, if it would be correct ;-/ The current code has a nasty hole -
3753 * it doesn't catch files in flight. We may send the descriptor to ourselves
3754 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3756 * Nasty bug: do_SAK is being called in interrupt context. This can
3757 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3759 void __do_SAK(struct tty_struct
*tty
)
3764 struct task_struct
*g
, *p
;
3765 struct pid
*session
;
3768 struct fdtable
*fdt
;
3772 session
= tty
->session
;
3774 tty_ldisc_flush(tty
);
3776 tty_driver_flush_buffer(tty
);
3778 read_lock(&tasklist_lock
);
3779 /* Kill the entire session */
3780 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
3781 printk(KERN_NOTICE
"SAK: killed process %d"
3782 " (%s): task_session_nr(p)==tty->session\n",
3783 task_pid_nr(p
), p
->comm
);
3784 send_sig(SIGKILL
, p
, 1);
3785 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
3786 /* Now kill any processes that happen to have the
3789 do_each_thread(g
, p
) {
3790 if (p
->signal
->tty
== tty
) {
3791 printk(KERN_NOTICE
"SAK: killed process %d"
3792 " (%s): task_session_nr(p)==tty->session\n",
3793 task_pid_nr(p
), p
->comm
);
3794 send_sig(SIGKILL
, p
, 1);
3800 * We don't take a ref to the file, so we must
3801 * hold ->file_lock instead.
3803 spin_lock(&p
->files
->file_lock
);
3804 fdt
= files_fdtable(p
->files
);
3805 for (i
= 0; i
< fdt
->max_fds
; i
++) {
3806 filp
= fcheck_files(p
->files
, i
);
3809 if (filp
->f_op
->read
== tty_read
&&
3810 filp
->private_data
== tty
) {
3811 printk(KERN_NOTICE
"SAK: killed process %d"
3812 " (%s): fd#%d opened to the tty\n",
3813 task_pid_nr(p
), p
->comm
, i
);
3814 force_sig(SIGKILL
, p
);
3818 spin_unlock(&p
->files
->file_lock
);
3821 } while_each_thread(g
, p
);
3822 read_unlock(&tasklist_lock
);
3826 static void do_SAK_work(struct work_struct
*work
)
3828 struct tty_struct
*tty
=
3829 container_of(work
, struct tty_struct
, SAK_work
);
3834 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3835 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3836 * the values which we write to it will be identical to the values which it
3837 * already has. --akpm
3839 void do_SAK(struct tty_struct
*tty
)
3843 schedule_work(&tty
->SAK_work
);
3846 EXPORT_SYMBOL(do_SAK
);
3850 * @work: tty structure passed from work queue.
3852 * This routine is called out of the software interrupt to flush data
3853 * from the buffer chain to the line discipline.
3855 * Locking: holds tty->buf.lock to guard buffer list. Drops the lock
3856 * while invoking the line discipline receive_buf method. The
3857 * receive_buf method is single threaded for each tty instance.
3860 static void flush_to_ldisc(struct work_struct
*work
)
3862 struct tty_struct
*tty
=
3863 container_of(work
, struct tty_struct
, buf
.work
.work
);
3864 unsigned long flags
;
3865 struct tty_ldisc
*disc
;
3866 struct tty_buffer
*tbuf
, *head
;
3868 unsigned char *flag_buf
;
3870 disc
= tty_ldisc_ref(tty
);
3871 if (disc
== NULL
) /* !TTY_LDISC */
3874 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3875 /* So we know a flush is running */
3876 set_bit(TTY_FLUSHING
, &tty
->flags
);
3877 head
= tty
->buf
.head
;
3879 tty
->buf
.head
= NULL
;
3881 int count
= head
->commit
- head
->read
;
3883 if (head
->next
== NULL
)
3887 tty_buffer_free(tty
, tbuf
);
3890 /* Ldisc or user is trying to flush the buffers
3891 we are feeding to the ldisc, stop feeding the
3892 line discipline as we want to empty the queue */
3893 if (test_bit(TTY_FLUSHPENDING
, &tty
->flags
))
3895 if (!tty
->receive_room
) {
3896 schedule_delayed_work(&tty
->buf
.work
, 1);
3899 if (count
> tty
->receive_room
)
3900 count
= tty
->receive_room
;
3901 char_buf
= head
->char_buf_ptr
+ head
->read
;
3902 flag_buf
= head
->flag_buf_ptr
+ head
->read
;
3903 head
->read
+= count
;
3904 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3905 disc
->ops
->receive_buf(tty
, char_buf
,
3907 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3909 /* Restore the queue head */
3910 tty
->buf
.head
= head
;
3912 /* We may have a deferred request to flush the input buffer,
3913 if so pull the chain under the lock and empty the queue */
3914 if (test_bit(TTY_FLUSHPENDING
, &tty
->flags
)) {
3915 __tty_buffer_flush(tty
);
3916 clear_bit(TTY_FLUSHPENDING
, &tty
->flags
);
3917 wake_up(&tty
->read_wait
);
3919 clear_bit(TTY_FLUSHING
, &tty
->flags
);
3920 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3922 tty_ldisc_deref(disc
);
3926 * tty_flip_buffer_push - terminal
3929 * Queue a push of the terminal flip buffers to the line discipline. This
3930 * function must not be called from IRQ context if tty->low_latency is set.
3932 * In the event of the queue being busy for flipping the work will be
3933 * held off and retried later.
3935 * Locking: tty buffer lock. Driver locks in low latency mode.
3938 void tty_flip_buffer_push(struct tty_struct
*tty
)
3940 unsigned long flags
;
3941 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3942 if (tty
->buf
.tail
!= NULL
)
3943 tty
->buf
.tail
->commit
= tty
->buf
.tail
->used
;
3944 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3946 if (tty
->low_latency
)
3947 flush_to_ldisc(&tty
->buf
.work
.work
);
3949 schedule_delayed_work(&tty
->buf
.work
, 1);
3952 EXPORT_SYMBOL(tty_flip_buffer_push
);
3956 * initialize_tty_struct
3957 * @tty: tty to initialize
3959 * This subroutine initializes a tty structure that has been newly
3962 * Locking: none - tty in question must not be exposed at this point
3965 static void initialize_tty_struct(struct tty_struct
*tty
)
3967 struct tty_ldisc ld
;
3968 memset(tty
, 0, sizeof(struct tty_struct
));
3969 tty
->magic
= TTY_MAGIC
;
3970 if (tty_ldisc_get(N_TTY
, &ld
) < 0)
3971 panic("n_tty: init_tty");
3972 tty_ldisc_assign(tty
, &ld
);
3973 tty
->session
= NULL
;
3975 tty
->overrun_time
= jiffies
;
3976 tty
->buf
.head
= tty
->buf
.tail
= NULL
;
3977 tty_buffer_init(tty
);
3978 INIT_DELAYED_WORK(&tty
->buf
.work
, flush_to_ldisc
);
3979 mutex_init(&tty
->termios_mutex
);
3980 init_waitqueue_head(&tty
->write_wait
);
3981 init_waitqueue_head(&tty
->read_wait
);
3982 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
3983 mutex_init(&tty
->atomic_read_lock
);
3984 mutex_init(&tty
->atomic_write_lock
);
3985 spin_lock_init(&tty
->read_lock
);
3986 spin_lock_init(&tty
->ctrl_lock
);
3987 INIT_LIST_HEAD(&tty
->tty_files
);
3988 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
3992 * tty_put_char - write one character to a tty
3996 * Write one byte to the tty using the provided put_char method
3997 * if present. Returns the number of characters successfully output.
3999 * Note: the specific put_char operation in the driver layer may go
4000 * away soon. Don't call it directly, use this method
4003 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
4005 if (tty
->ops
->put_char
)
4006 return tty
->ops
->put_char(tty
, ch
);
4007 return tty
->ops
->write(tty
, &ch
, 1);
4010 EXPORT_SYMBOL_GPL(tty_put_char
);
4012 static struct class *tty_class
;
4015 * tty_register_device - register a tty device
4016 * @driver: the tty driver that describes the tty device
4017 * @index: the index in the tty driver for this tty device
4018 * @device: a struct device that is associated with this tty device.
4019 * This field is optional, if there is no known struct device
4020 * for this tty device it can be set to NULL safely.
4022 * Returns a pointer to the struct device for this tty device
4023 * (or ERR_PTR(-EFOO) on error).
4025 * This call is required to be made to register an individual tty device
4026 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
4027 * that bit is not set, this function should not be called by a tty
4033 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
4034 struct device
*device
)
4037 dev_t dev
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
4039 if (index
>= driver
->num
) {
4040 printk(KERN_ERR
"Attempt to register invalid tty line number "
4042 return ERR_PTR(-EINVAL
);
4045 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
4046 pty_line_name(driver
, index
, name
);
4048 tty_line_name(driver
, index
, name
);
4050 return device_create(tty_class
, device
, dev
, name
);
4054 * tty_unregister_device - unregister a tty device
4055 * @driver: the tty driver that describes the tty device
4056 * @index: the index in the tty driver for this tty device
4058 * If a tty device is registered with a call to tty_register_device() then
4059 * this function must be called when the tty device is gone.
4064 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
4066 device_destroy(tty_class
,
4067 MKDEV(driver
->major
, driver
->minor_start
) + index
);
4070 EXPORT_SYMBOL(tty_register_device
);
4071 EXPORT_SYMBOL(tty_unregister_device
);
4073 struct tty_driver
*alloc_tty_driver(int lines
)
4075 struct tty_driver
*driver
;
4077 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
4079 driver
->magic
= TTY_DRIVER_MAGIC
;
4080 driver
->num
= lines
;
4081 /* later we'll move allocation of tables here */
4086 void put_tty_driver(struct tty_driver
*driver
)
4091 void tty_set_operations(struct tty_driver
*driver
,
4092 const struct tty_operations
*op
)
4097 EXPORT_SYMBOL(alloc_tty_driver
);
4098 EXPORT_SYMBOL(put_tty_driver
);
4099 EXPORT_SYMBOL(tty_set_operations
);
4102 * Called by a tty driver to register itself.
4104 int tty_register_driver(struct tty_driver
*driver
)
4111 if (driver
->flags
& TTY_DRIVER_INSTALLED
)
4114 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && driver
->num
) {
4115 p
= kzalloc(driver
->num
* 3 * sizeof(void *), GFP_KERNEL
);
4120 if (!driver
->major
) {
4121 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
4122 driver
->num
, driver
->name
);
4124 driver
->major
= MAJOR(dev
);
4125 driver
->minor_start
= MINOR(dev
);
4128 dev
= MKDEV(driver
->major
, driver
->minor_start
);
4129 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
4137 driver
->ttys
= (struct tty_struct
**)p
;
4138 driver
->termios
= (struct ktermios
**)(p
+ driver
->num
);
4139 driver
->termios_locked
= (struct ktermios
**)
4140 (p
+ driver
->num
* 2);
4142 driver
->ttys
= NULL
;
4143 driver
->termios
= NULL
;
4144 driver
->termios_locked
= NULL
;
4147 cdev_init(&driver
->cdev
, &tty_fops
);
4148 driver
->cdev
.owner
= driver
->owner
;
4149 error
= cdev_add(&driver
->cdev
, dev
, driver
->num
);
4151 unregister_chrdev_region(dev
, driver
->num
);
4152 driver
->ttys
= NULL
;
4153 driver
->termios
= driver
->termios_locked
= NULL
;
4158 mutex_lock(&tty_mutex
);
4159 list_add(&driver
->tty_drivers
, &tty_drivers
);
4160 mutex_unlock(&tty_mutex
);
4162 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
4163 for (i
= 0; i
< driver
->num
; i
++)
4164 tty_register_device(driver
, i
, NULL
);
4166 proc_tty_register_driver(driver
);
4170 EXPORT_SYMBOL(tty_register_driver
);
4173 * Called by a tty driver to unregister itself.
4175 int tty_unregister_driver(struct tty_driver
*driver
)
4178 struct ktermios
*tp
;
4181 if (driver
->refcount
)
4184 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
4186 mutex_lock(&tty_mutex
);
4187 list_del(&driver
->tty_drivers
);
4188 mutex_unlock(&tty_mutex
);
4191 * Free the termios and termios_locked structures because
4192 * we don't want to get memory leaks when modular tty
4193 * drivers are removed from the kernel.
4195 for (i
= 0; i
< driver
->num
; i
++) {
4196 tp
= driver
->termios
[i
];
4198 driver
->termios
[i
] = NULL
;
4201 tp
= driver
->termios_locked
[i
];
4203 driver
->termios_locked
[i
] = NULL
;
4206 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
4207 tty_unregister_device(driver
, i
);
4210 proc_tty_unregister_driver(driver
);
4211 driver
->ttys
= NULL
;
4212 driver
->termios
= driver
->termios_locked
= NULL
;
4214 cdev_del(&driver
->cdev
);
4217 EXPORT_SYMBOL(tty_unregister_driver
);
4219 dev_t
tty_devnum(struct tty_struct
*tty
)
4221 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
4223 EXPORT_SYMBOL(tty_devnum
);
4225 void proc_clear_tty(struct task_struct
*p
)
4227 spin_lock_irq(&p
->sighand
->siglock
);
4228 p
->signal
->tty
= NULL
;
4229 spin_unlock_irq(&p
->sighand
->siglock
);
4231 EXPORT_SYMBOL(proc_clear_tty
);
4233 /* Called under the sighand lock */
4235 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
4238 unsigned long flags
;
4239 /* We should not have a session or pgrp to put here but.... */
4240 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
4241 put_pid(tty
->session
);
4243 tty
->pgrp
= get_pid(task_pgrp(tsk
));
4244 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
4245 tty
->session
= get_pid(task_session(tsk
));
4247 put_pid(tsk
->signal
->tty_old_pgrp
);
4248 tsk
->signal
->tty
= tty
;
4249 tsk
->signal
->tty_old_pgrp
= NULL
;
4252 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
4254 spin_lock_irq(&tsk
->sighand
->siglock
);
4255 __proc_set_tty(tsk
, tty
);
4256 spin_unlock_irq(&tsk
->sighand
->siglock
);
4259 struct tty_struct
*get_current_tty(void)
4261 struct tty_struct
*tty
;
4262 WARN_ON_ONCE(!mutex_is_locked(&tty_mutex
));
4263 tty
= current
->signal
->tty
;
4265 * session->tty can be changed/cleared from under us, make sure we
4266 * issue the load. The obtained pointer, when not NULL, is valid as
4267 * long as we hold tty_mutex.
4272 EXPORT_SYMBOL_GPL(get_current_tty
);
4275 * Initialize the console device. This is called *early*, so
4276 * we can't necessarily depend on lots of kernel help here.
4277 * Just do some early initializations, and do the complex setup
4280 void __init
console_init(void)
4284 /* Setup the default TTY line discipline. */
4285 (void) tty_register_ldisc(N_TTY
, &tty_ldisc_N_TTY
);
4288 * set up the console device so that later boot sequences can
4289 * inform about problems etc..
4291 call
= __con_initcall_start
;
4292 while (call
< __con_initcall_end
) {
4298 static int __init
tty_class_init(void)
4300 tty_class
= class_create(THIS_MODULE
, "tty");
4301 if (IS_ERR(tty_class
))
4302 return PTR_ERR(tty_class
);
4306 postcore_initcall(tty_class_init
);
4308 /* 3/2004 jmc: why do these devices exist? */
4310 static struct cdev tty_cdev
, console_cdev
;
4311 #ifdef CONFIG_UNIX98_PTYS
4312 static struct cdev ptmx_cdev
;
4315 static struct cdev vc0_cdev
;
4319 * Ok, now we can initialize the rest of the tty devices and can count
4320 * on memory allocations, interrupts etc..
4322 static int __init
tty_init(void)
4324 cdev_init(&tty_cdev
, &tty_fops
);
4325 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
4326 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
4327 panic("Couldn't register /dev/tty driver\n");
4328 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), "tty");
4330 cdev_init(&console_cdev
, &console_fops
);
4331 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
4332 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
4333 panic("Couldn't register /dev/console driver\n");
4334 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), "console");
4336 #ifdef CONFIG_UNIX98_PTYS
4337 cdev_init(&ptmx_cdev
, &ptmx_fops
);
4338 if (cdev_add(&ptmx_cdev
, MKDEV(TTYAUX_MAJOR
, 2), 1) ||
4339 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 2), 1, "/dev/ptmx") < 0)
4340 panic("Couldn't register /dev/ptmx driver\n");
4341 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 2), "ptmx");
4345 cdev_init(&vc0_cdev
, &console_fops
);
4346 if (cdev_add(&vc0_cdev
, MKDEV(TTY_MAJOR
, 0), 1) ||
4347 register_chrdev_region(MKDEV(TTY_MAJOR
, 0), 1, "/dev/vc/0") < 0)
4348 panic("Couldn't register /dev/tty0 driver\n");
4349 device_create(tty_class
, NULL
, MKDEV(TTY_MAJOR
, 0), "tty0");
4355 module_init(tty_init
);