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() -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
68 #include <linux/types.h>
69 #include <linux/major.h>
70 #include <linux/errno.h>
71 #include <linux/signal.h>
72 #include <linux/fcntl.h>
73 #include <linux/sched.h>
74 #include <linux/interrupt.h>
75 #include <linux/tty.h>
76 #include <linux/tty_driver.h>
77 #include <linux/tty_flip.h>
78 #include <linux/devpts_fs.h>
79 #include <linux/file.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/smp_lock.h>
92 #include <linux/device.h>
93 #include <linux/idr.h>
94 #include <linux/wait.h>
95 #include <linux/bitops.h>
96 #include <linux/delay.h>
98 #include <asm/uaccess.h>
99 #include <asm/system.h>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
107 #undef TTY_DEBUG_HANGUP
109 #define TTY_PARANOIA_CHECK 1
110 #define CHECK_TTY_COUNT 1
112 struct ktermios tty_std_termios
= { /* for the benefit of tty drivers */
113 .c_iflag
= ICRNL
| IXON
,
114 .c_oflag
= OPOST
| ONLCR
,
115 .c_cflag
= B38400
| CS8
| CREAD
| HUPCL
,
116 .c_lflag
= ISIG
| ICANON
| ECHO
| ECHOE
| ECHOK
|
117 ECHOCTL
| ECHOKE
| IEXTEN
,
123 EXPORT_SYMBOL(tty_std_termios
);
125 /* This list gets poked at by procfs and various bits of boot up code. This
126 could do with some rationalisation such as pulling the tty proc function
129 LIST_HEAD(tty_drivers
); /* linked list of tty drivers */
131 /* Mutex to protect creating and releasing a tty. This is shared with
132 vt.c for deeply disgusting hack reasons */
133 DEFINE_MUTEX(tty_mutex
);
134 EXPORT_SYMBOL(tty_mutex
);
136 #ifdef CONFIG_UNIX98_PTYS
137 extern struct tty_driver
*ptm_driver
; /* Unix98 pty masters; for /dev/ptmx */
138 extern int pty_limit
; /* Config limit on Unix98 ptys */
139 static DEFINE_IDR(allocated_ptys
);
140 static DECLARE_MUTEX(allocated_ptys_lock
);
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
*, size_t, loff_t
*);
149 static unsigned int tty_poll(struct file
*, poll_table
*);
150 static int tty_open(struct inode
*, struct file
*);
151 static int tty_release(struct inode
*, struct file
*);
152 int tty_ioctl(struct inode
* inode
, struct file
* file
,
153 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
380 static void tty_buffer_flush(struct tty_struct
*tty
)
382 struct tty_buffer
*thead
;
385 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
386 while((thead
= tty
->buf
.head
) != NULL
) {
387 tty
->buf
.head
= thead
->next
;
388 tty_buffer_free(tty
, thead
);
390 tty
->buf
.tail
= NULL
;
391 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
395 * tty_buffer_find - find a free tty buffer
396 * @tty: tty owning the buffer
397 * @size: characters wanted
399 * Locate an existing suitable tty buffer or if we are lacking one then
400 * allocate a new one. We round our buffers off in 256 character chunks
401 * to get better allocation behaviour.
403 * Locking: Caller must hold tty->buf.lock
406 static struct tty_buffer
*tty_buffer_find(struct tty_struct
*tty
, size_t size
)
408 struct tty_buffer
**tbh
= &tty
->buf
.free
;
409 while((*tbh
) != NULL
) {
410 struct tty_buffer
*t
= *tbh
;
411 if(t
->size
>= size
) {
417 tty
->buf
.memory_used
+= t
->size
;
420 tbh
= &((*tbh
)->next
);
422 /* Round the buffer size out */
423 size
= (size
+ 0xFF) & ~ 0xFF;
424 return tty_buffer_alloc(tty
, size
);
425 /* Should possibly check if this fails for the largest buffer we
426 have queued and recycle that ? */
430 * tty_buffer_request_room - grow tty buffer if needed
431 * @tty: tty structure
432 * @size: size desired
434 * Make at least size bytes of linear space available for the tty
435 * buffer. If we fail return the size we managed to find.
437 * Locking: Takes tty->buf.lock
439 int tty_buffer_request_room(struct tty_struct
*tty
, size_t size
)
441 struct tty_buffer
*b
, *n
;
445 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
447 /* OPTIMISATION: We could keep a per tty "zero" sized buffer to
448 remove this conditional if its worth it. This would be invisible
450 if ((b
= tty
->buf
.tail
) != NULL
)
451 left
= b
->size
- b
->used
;
456 /* This is the slow path - looking for new buffers to use */
457 if ((n
= tty_buffer_find(tty
, size
)) != NULL
) {
468 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
471 EXPORT_SYMBOL_GPL(tty_buffer_request_room
);
474 * tty_insert_flip_string - Add characters to the tty buffer
475 * @tty: tty structure
479 * Queue a series of bytes to the tty buffering. All the characters
480 * passed are marked as without error. Returns the number added.
482 * Locking: Called functions may take tty->buf.lock
485 int tty_insert_flip_string(struct tty_struct
*tty
, const unsigned char *chars
,
490 int space
= tty_buffer_request_room(tty
, size
- copied
);
491 struct tty_buffer
*tb
= tty
->buf
.tail
;
492 /* If there is no space then tb may be NULL */
493 if(unlikely(space
== 0))
495 memcpy(tb
->char_buf_ptr
+ tb
->used
, chars
, space
);
496 memset(tb
->flag_buf_ptr
+ tb
->used
, TTY_NORMAL
, space
);
500 /* There is a small chance that we need to split the data over
501 several buffers. If this is the case we must loop */
502 } while (unlikely(size
> copied
));
505 EXPORT_SYMBOL(tty_insert_flip_string
);
508 * tty_insert_flip_string_flags - Add characters to the tty buffer
509 * @tty: tty structure
514 * Queue a series of bytes to the tty buffering. For each character
515 * the flags array indicates the status of the character. Returns the
518 * Locking: Called functions may take tty->buf.lock
521 int tty_insert_flip_string_flags(struct tty_struct
*tty
,
522 const unsigned char *chars
, const char *flags
, size_t size
)
526 int space
= tty_buffer_request_room(tty
, size
- copied
);
527 struct tty_buffer
*tb
= tty
->buf
.tail
;
528 /* If there is no space then tb may be NULL */
529 if(unlikely(space
== 0))
531 memcpy(tb
->char_buf_ptr
+ tb
->used
, chars
, space
);
532 memcpy(tb
->flag_buf_ptr
+ tb
->used
, flags
, space
);
537 /* There is a small chance that we need to split the data over
538 several buffers. If this is the case we must loop */
539 } while (unlikely(size
> copied
));
542 EXPORT_SYMBOL(tty_insert_flip_string_flags
);
545 * tty_schedule_flip - push characters to ldisc
546 * @tty: tty to push from
548 * Takes any pending buffers and transfers their ownership to the
549 * ldisc side of the queue. It then schedules those characters for
550 * processing by the line discipline.
552 * Locking: Takes tty->buf.lock
555 void tty_schedule_flip(struct tty_struct
*tty
)
558 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
559 if (tty
->buf
.tail
!= NULL
)
560 tty
->buf
.tail
->commit
= tty
->buf
.tail
->used
;
561 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
562 schedule_delayed_work(&tty
->buf
.work
, 1);
564 EXPORT_SYMBOL(tty_schedule_flip
);
567 * tty_prepare_flip_string - make room for characters
569 * @chars: return pointer for character write area
570 * @size: desired size
572 * Prepare a block of space in the buffer for data. Returns the length
573 * available and buffer pointer to the space which is now allocated and
574 * accounted for as ready for normal characters. This is used for drivers
575 * that need their own block copy routines into the buffer. There is no
576 * guarantee the buffer is a DMA target!
578 * Locking: May call functions taking tty->buf.lock
581 int tty_prepare_flip_string(struct tty_struct
*tty
, unsigned char **chars
, size_t size
)
583 int space
= tty_buffer_request_room(tty
, size
);
585 struct tty_buffer
*tb
= tty
->buf
.tail
;
586 *chars
= tb
->char_buf_ptr
+ tb
->used
;
587 memset(tb
->flag_buf_ptr
+ tb
->used
, TTY_NORMAL
, space
);
593 EXPORT_SYMBOL_GPL(tty_prepare_flip_string
);
596 * tty_prepare_flip_string_flags - make room for characters
598 * @chars: return pointer for character write area
599 * @flags: return pointer for status flag write area
600 * @size: desired size
602 * Prepare a block of space in the buffer for data. Returns the length
603 * available and buffer pointer to the space which is now allocated and
604 * accounted for as ready for characters. This is used for drivers
605 * that need their own block copy routines into the buffer. There is no
606 * guarantee the buffer is a DMA target!
608 * Locking: May call functions taking tty->buf.lock
611 int tty_prepare_flip_string_flags(struct tty_struct
*tty
, unsigned char **chars
, char **flags
, size_t size
)
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 *flags
= tb
->flag_buf_ptr
+ tb
->used
;
623 EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags
);
628 * tty_set_termios_ldisc - set ldisc field
629 * @tty: tty structure
630 * @num: line discipline number
632 * This is probably overkill for real world processors but
633 * they are not on hot paths so a little discipline won't do
636 * Locking: takes termios_mutex
639 static void tty_set_termios_ldisc(struct tty_struct
*tty
, int num
)
641 mutex_lock(&tty
->termios_mutex
);
642 tty
->termios
->c_line
= num
;
643 mutex_unlock(&tty
->termios_mutex
);
647 * This guards the refcounted line discipline lists. The lock
648 * must be taken with irqs off because there are hangup path
649 * callers who will do ldisc lookups and cannot sleep.
652 static DEFINE_SPINLOCK(tty_ldisc_lock
);
653 static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait
);
654 static struct tty_ldisc tty_ldiscs
[NR_LDISCS
]; /* line disc dispatch table */
657 * tty_register_ldisc - install a line discipline
658 * @disc: ldisc number
659 * @new_ldisc: pointer to the ldisc object
661 * Installs a new line discipline into the kernel. The discipline
662 * is set up as unreferenced and then made available to the kernel
663 * from this point onwards.
666 * takes tty_ldisc_lock to guard against ldisc races
669 int tty_register_ldisc(int disc
, struct tty_ldisc
*new_ldisc
)
674 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
677 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
678 tty_ldiscs
[disc
] = *new_ldisc
;
679 tty_ldiscs
[disc
].num
= disc
;
680 tty_ldiscs
[disc
].flags
|= LDISC_FLAG_DEFINED
;
681 tty_ldiscs
[disc
].refcount
= 0;
682 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
686 EXPORT_SYMBOL(tty_register_ldisc
);
689 * tty_unregister_ldisc - unload a line discipline
690 * @disc: ldisc number
691 * @new_ldisc: pointer to the ldisc object
693 * Remove a line discipline from the kernel providing it is not
697 * takes tty_ldisc_lock to guard against ldisc races
700 int tty_unregister_ldisc(int disc
)
705 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
708 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
709 if (tty_ldiscs
[disc
].refcount
)
712 tty_ldiscs
[disc
].flags
&= ~LDISC_FLAG_DEFINED
;
713 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
717 EXPORT_SYMBOL(tty_unregister_ldisc
);
720 * tty_ldisc_get - take a reference to an ldisc
721 * @disc: ldisc number
723 * Takes a reference to a line discipline. Deals with refcounts and
724 * module locking counts. Returns NULL if the discipline is not available.
725 * Returns a pointer to the discipline and bumps the ref count if it is
729 * takes tty_ldisc_lock to guard against ldisc races
732 struct tty_ldisc
*tty_ldisc_get(int disc
)
735 struct tty_ldisc
*ld
;
737 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
740 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
742 ld
= &tty_ldiscs
[disc
];
743 /* Check the entry is defined */
744 if(ld
->flags
& LDISC_FLAG_DEFINED
)
746 /* If the module is being unloaded we can't use it */
747 if (!try_module_get(ld
->owner
))
754 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
758 EXPORT_SYMBOL_GPL(tty_ldisc_get
);
761 * tty_ldisc_put - drop ldisc reference
762 * @disc: ldisc number
764 * Drop a reference to a line discipline. Manage refcounts and
765 * module usage counts
768 * takes tty_ldisc_lock to guard against ldisc races
771 void tty_ldisc_put(int disc
)
773 struct tty_ldisc
*ld
;
776 BUG_ON(disc
< N_TTY
|| disc
>= NR_LDISCS
);
778 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
779 ld
= &tty_ldiscs
[disc
];
780 BUG_ON(ld
->refcount
== 0);
782 module_put(ld
->owner
);
783 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
786 EXPORT_SYMBOL_GPL(tty_ldisc_put
);
789 * tty_ldisc_assign - set ldisc on a tty
790 * @tty: tty to assign
791 * @ld: line discipline
793 * Install an instance of a line discipline into a tty structure. The
794 * ldisc must have a reference count above zero to ensure it remains/
795 * The tty instance refcount starts at zero.
798 * Caller must hold references
801 static void tty_ldisc_assign(struct tty_struct
*tty
, struct tty_ldisc
*ld
)
804 tty
->ldisc
.refcount
= 0;
808 * tty_ldisc_try - internal helper
811 * Make a single attempt to grab and bump the refcount on
812 * the tty ldisc. Return 0 on failure or 1 on success. This is
813 * used to implement both the waiting and non waiting versions
816 * Locking: takes tty_ldisc_lock
819 static int tty_ldisc_try(struct tty_struct
*tty
)
822 struct tty_ldisc
*ld
;
825 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
827 if(test_bit(TTY_LDISC
, &tty
->flags
))
832 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
837 * tty_ldisc_ref_wait - wait for the tty ldisc
840 * Dereference the line discipline for the terminal and take a
841 * reference to it. If the line discipline is in flux then
842 * wait patiently until it changes.
844 * Note: Must not be called from an IRQ/timer context. The caller
845 * must also be careful not to hold other locks that will deadlock
846 * against a discipline change, such as an existing ldisc reference
847 * (which we check for)
849 * Locking: call functions take tty_ldisc_lock
852 struct tty_ldisc
*tty_ldisc_ref_wait(struct tty_struct
*tty
)
854 /* wait_event is a macro */
855 wait_event(tty_ldisc_wait
, tty_ldisc_try(tty
));
856 if(tty
->ldisc
.refcount
== 0)
857 printk(KERN_ERR
"tty_ldisc_ref_wait\n");
861 EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait
);
864 * tty_ldisc_ref - get the tty ldisc
867 * Dereference the line discipline for the terminal and take a
868 * reference to it. If the line discipline is in flux then
869 * return NULL. Can be called from IRQ and timer functions.
871 * Locking: called functions take tty_ldisc_lock
874 struct tty_ldisc
*tty_ldisc_ref(struct tty_struct
*tty
)
876 if(tty_ldisc_try(tty
))
881 EXPORT_SYMBOL_GPL(tty_ldisc_ref
);
884 * tty_ldisc_deref - free a tty ldisc reference
885 * @ld: reference to free up
887 * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May
888 * be called in IRQ context.
890 * Locking: takes tty_ldisc_lock
893 void tty_ldisc_deref(struct tty_ldisc
*ld
)
899 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
900 if(ld
->refcount
== 0)
901 printk(KERN_ERR
"tty_ldisc_deref: no references.\n");
904 if(ld
->refcount
== 0)
905 wake_up(&tty_ldisc_wait
);
906 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
909 EXPORT_SYMBOL_GPL(tty_ldisc_deref
);
912 * tty_ldisc_enable - allow ldisc use
913 * @tty: terminal to activate ldisc on
915 * Set the TTY_LDISC flag when the line discipline can be called
916 * again. Do neccessary wakeups for existing sleepers.
918 * Note: nobody should set this bit except via this function. Clearing
919 * directly is allowed.
922 static void tty_ldisc_enable(struct tty_struct
*tty
)
924 set_bit(TTY_LDISC
, &tty
->flags
);
925 wake_up(&tty_ldisc_wait
);
929 * tty_set_ldisc - set line discipline
930 * @tty: the terminal to set
931 * @ldisc: the line discipline
933 * Set the discipline of a tty line. Must be called from a process
936 * Locking: takes tty_ldisc_lock.
937 * called functions take termios_mutex
940 static int tty_set_ldisc(struct tty_struct
*tty
, int ldisc
)
943 struct tty_ldisc o_ldisc
;
947 struct tty_ldisc
*ld
;
948 struct tty_struct
*o_tty
;
950 if ((ldisc
< N_TTY
) || (ldisc
>= NR_LDISCS
))
955 ld
= tty_ldisc_get(ldisc
);
956 /* Eduardo Blanco <ejbs@cs.cs.com.uy> */
957 /* Cyrus Durgin <cider@speakeasy.org> */
959 request_module("tty-ldisc-%d", ldisc
);
960 ld
= tty_ldisc_get(ldisc
);
966 * Problem: What do we do if this blocks ?
969 tty_wait_until_sent(tty
, 0);
971 if (tty
->ldisc
.num
== ldisc
) {
972 tty_ldisc_put(ldisc
);
977 * No more input please, we are switching. The new ldisc
978 * will update this value in the ldisc open function
981 tty
->receive_room
= 0;
983 o_ldisc
= tty
->ldisc
;
987 * Make sure we don't change while someone holds a
988 * reference to the line discipline. The TTY_LDISC bit
989 * prevents anyone taking a reference once it is clear.
990 * We need the lock to avoid racing reference takers.
993 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
994 if (tty
->ldisc
.refcount
|| (o_tty
&& o_tty
->ldisc
.refcount
)) {
995 if(tty
->ldisc
.refcount
) {
996 /* Free the new ldisc we grabbed. Must drop the lock
998 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
999 tty_ldisc_put(ldisc
);
1001 * There are several reasons we may be busy, including
1002 * random momentary I/O traffic. We must therefore
1003 * retry. We could distinguish between blocking ops
1004 * and retries if we made tty_ldisc_wait() smarter. That
1005 * is up for discussion.
1007 if (wait_event_interruptible(tty_ldisc_wait
, tty
->ldisc
.refcount
== 0) < 0)
1008 return -ERESTARTSYS
;
1011 if(o_tty
&& o_tty
->ldisc
.refcount
) {
1012 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1013 tty_ldisc_put(ldisc
);
1014 if (wait_event_interruptible(tty_ldisc_wait
, o_tty
->ldisc
.refcount
== 0) < 0)
1015 return -ERESTARTSYS
;
1020 /* if the TTY_LDISC bit is set, then we are racing against another ldisc change */
1022 if (!test_bit(TTY_LDISC
, &tty
->flags
)) {
1023 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1024 tty_ldisc_put(ldisc
);
1025 ld
= tty_ldisc_ref_wait(tty
);
1026 tty_ldisc_deref(ld
);
1030 clear_bit(TTY_LDISC
, &tty
->flags
);
1032 clear_bit(TTY_LDISC
, &o_tty
->flags
);
1033 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1036 * From this point on we know nobody has an ldisc
1037 * usage reference, nor can they obtain one until
1038 * we say so later on.
1041 work
= cancel_delayed_work(&tty
->buf
.work
);
1043 * Wait for ->hangup_work and ->buf.work handlers to terminate
1046 flush_scheduled_work();
1047 /* Shutdown the current discipline. */
1048 if (tty
->ldisc
.close
)
1049 (tty
->ldisc
.close
)(tty
);
1051 /* Now set up the new line discipline. */
1052 tty_ldisc_assign(tty
, ld
);
1053 tty_set_termios_ldisc(tty
, ldisc
);
1054 if (tty
->ldisc
.open
)
1055 retval
= (tty
->ldisc
.open
)(tty
);
1057 tty_ldisc_put(ldisc
);
1058 /* There is an outstanding reference here so this is safe */
1059 tty_ldisc_assign(tty
, tty_ldisc_get(o_ldisc
.num
));
1060 tty_set_termios_ldisc(tty
, tty
->ldisc
.num
);
1061 if (tty
->ldisc
.open
&& (tty
->ldisc
.open(tty
) < 0)) {
1062 tty_ldisc_put(o_ldisc
.num
);
1063 /* This driver is always present */
1064 tty_ldisc_assign(tty
, tty_ldisc_get(N_TTY
));
1065 tty_set_termios_ldisc(tty
, N_TTY
);
1066 if (tty
->ldisc
.open
) {
1067 int r
= tty
->ldisc
.open(tty
);
1070 panic("Couldn't open N_TTY ldisc for "
1072 tty_name(tty
, buf
), r
);
1076 /* At this point we hold a reference to the new ldisc and a
1077 a reference to the old ldisc. If we ended up flipping back
1078 to the existing ldisc we have two references to it */
1080 if (tty
->ldisc
.num
!= o_ldisc
.num
&& tty
->driver
->set_ldisc
)
1081 tty
->driver
->set_ldisc(tty
);
1083 tty_ldisc_put(o_ldisc
.num
);
1086 * Allow ldisc referencing to occur as soon as the driver
1087 * ldisc callback completes.
1090 tty_ldisc_enable(tty
);
1092 tty_ldisc_enable(o_tty
);
1094 /* Restart it in case no characters kick it off. Safe if
1097 schedule_delayed_work(&tty
->buf
.work
, 1);
1102 * get_tty_driver - find device of a tty
1103 * @dev_t: device identifier
1104 * @index: returns the index of the tty
1106 * This routine returns a tty driver structure, given a device number
1107 * and also passes back the index number.
1109 * Locking: caller must hold tty_mutex
1112 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
1114 struct tty_driver
*p
;
1116 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
1117 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
1118 if (device
< base
|| device
>= base
+ p
->num
)
1120 *index
= device
- base
;
1127 * tty_check_change - check for POSIX terminal changes
1128 * @tty: tty to check
1130 * If we try to write to, or set the state of, a terminal and we're
1131 * not in the foreground, send a SIGTTOU. If the signal is blocked or
1132 * ignored, go ahead and perform the operation. (POSIX 7.2)
1137 int tty_check_change(struct tty_struct
* tty
)
1139 if (current
->signal
->tty
!= tty
)
1142 printk(KERN_WARNING
"tty_check_change: tty->pgrp == NULL!\n");
1145 if (task_pgrp(current
) == tty
->pgrp
)
1147 if (is_ignored(SIGTTOU
))
1149 if (is_current_pgrp_orphaned())
1151 kill_pgrp(task_pgrp(current
), SIGTTOU
, 1);
1152 set_thread_flag(TIF_SIGPENDING
);
1153 return -ERESTARTSYS
;
1156 EXPORT_SYMBOL(tty_check_change
);
1158 static ssize_t
hung_up_tty_read(struct file
* file
, char __user
* buf
,
1159 size_t count
, loff_t
*ppos
)
1164 static ssize_t
hung_up_tty_write(struct file
* file
, const char __user
* buf
,
1165 size_t count
, loff_t
*ppos
)
1170 /* No kernel lock held - none needed ;) */
1171 static unsigned int hung_up_tty_poll(struct file
* filp
, poll_table
* wait
)
1173 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
1176 static int hung_up_tty_ioctl(struct inode
* inode
, struct file
* file
,
1177 unsigned int cmd
, unsigned long arg
)
1179 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
1182 static long hung_up_tty_compat_ioctl(struct file
* file
,
1183 unsigned int cmd
, unsigned long arg
)
1185 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
1188 static const struct file_operations tty_fops
= {
1189 .llseek
= no_llseek
,
1194 .compat_ioctl
= tty_compat_ioctl
,
1196 .release
= tty_release
,
1197 .fasync
= tty_fasync
,
1200 #ifdef CONFIG_UNIX98_PTYS
1201 static const struct file_operations ptmx_fops
= {
1202 .llseek
= no_llseek
,
1207 .compat_ioctl
= tty_compat_ioctl
,
1209 .release
= tty_release
,
1210 .fasync
= tty_fasync
,
1214 static const struct file_operations console_fops
= {
1215 .llseek
= no_llseek
,
1217 .write
= redirected_tty_write
,
1220 .compat_ioctl
= tty_compat_ioctl
,
1222 .release
= tty_release
,
1223 .fasync
= tty_fasync
,
1226 static const struct file_operations hung_up_tty_fops
= {
1227 .llseek
= no_llseek
,
1228 .read
= hung_up_tty_read
,
1229 .write
= hung_up_tty_write
,
1230 .poll
= hung_up_tty_poll
,
1231 .ioctl
= hung_up_tty_ioctl
,
1232 .compat_ioctl
= hung_up_tty_compat_ioctl
,
1233 .release
= tty_release
,
1236 static DEFINE_SPINLOCK(redirect_lock
);
1237 static struct file
*redirect
;
1240 * tty_wakeup - request more data
1243 * Internal and external helper for wakeups of tty. This function
1244 * informs the line discipline if present that the driver is ready
1245 * to receive more output data.
1248 void tty_wakeup(struct tty_struct
*tty
)
1250 struct tty_ldisc
*ld
;
1252 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
1253 ld
= tty_ldisc_ref(tty
);
1255 if(ld
->write_wakeup
)
1256 ld
->write_wakeup(tty
);
1257 tty_ldisc_deref(ld
);
1260 wake_up_interruptible(&tty
->write_wait
);
1263 EXPORT_SYMBOL_GPL(tty_wakeup
);
1266 * tty_ldisc_flush - flush line discipline queue
1269 * Flush the line discipline queue (if any) for this tty. If there
1270 * is no line discipline active this is a no-op.
1273 void tty_ldisc_flush(struct tty_struct
*tty
)
1275 struct tty_ldisc
*ld
= tty_ldisc_ref(tty
);
1277 if(ld
->flush_buffer
)
1278 ld
->flush_buffer(tty
);
1279 tty_ldisc_deref(ld
);
1281 tty_buffer_flush(tty
);
1284 EXPORT_SYMBOL_GPL(tty_ldisc_flush
);
1287 * tty_reset_termios - reset terminal state
1288 * @tty: tty to reset
1290 * Restore a terminal to the driver default state
1293 static void tty_reset_termios(struct tty_struct
*tty
)
1295 mutex_lock(&tty
->termios_mutex
);
1296 *tty
->termios
= tty
->driver
->init_termios
;
1297 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
1298 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
1299 mutex_unlock(&tty
->termios_mutex
);
1303 * do_tty_hangup - actual handler for hangup events
1306 * This can be called by the "eventd" kernel thread. That is process
1307 * synchronous but doesn't hold any locks, so we need to make sure we
1308 * have the appropriate locks for what we're doing.
1310 * The hangup event clears any pending redirections onto the hung up
1311 * device. It ensures future writes will error and it does the needed
1312 * line discipline hangup and signal delivery. The tty object itself
1317 * redirect lock for undoing redirection
1318 * file list lock for manipulating list of ttys
1319 * tty_ldisc_lock from called functions
1320 * termios_mutex resetting termios data
1321 * tasklist_lock to walk task list for hangup event
1322 * ->siglock to protect ->signal/->sighand
1324 static void do_tty_hangup(struct work_struct
*work
)
1326 struct tty_struct
*tty
=
1327 container_of(work
, struct tty_struct
, hangup_work
);
1328 struct file
* cons_filp
= NULL
;
1329 struct file
*filp
, *f
= NULL
;
1330 struct task_struct
*p
;
1331 struct tty_ldisc
*ld
;
1332 int closecount
= 0, n
;
1337 /* inuse_filps is protected by the single kernel lock */
1340 spin_lock(&redirect_lock
);
1341 if (redirect
&& redirect
->private_data
== tty
) {
1345 spin_unlock(&redirect_lock
);
1347 check_tty_count(tty
, "do_tty_hangup");
1349 /* This breaks for file handles being sent over AF_UNIX sockets ? */
1350 list_for_each_entry(filp
, &tty
->tty_files
, f_u
.fu_list
) {
1351 if (filp
->f_op
->write
== redirected_tty_write
)
1353 if (filp
->f_op
->write
!= tty_write
)
1356 tty_fasync(-1, filp
, 0); /* can't block */
1357 filp
->f_op
= &hung_up_tty_fops
;
1361 /* FIXME! What are the locking issues here? This may me overdoing things..
1362 * this question is especially important now that we've removed the irqlock. */
1364 ld
= tty_ldisc_ref(tty
);
1365 if(ld
!= NULL
) /* We may have no line discipline at this point */
1367 if (ld
->flush_buffer
)
1368 ld
->flush_buffer(tty
);
1369 if (tty
->driver
->flush_buffer
)
1370 tty
->driver
->flush_buffer(tty
);
1371 if ((test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) &&
1373 ld
->write_wakeup(tty
);
1378 /* FIXME: Once we trust the LDISC code better we can wait here for
1379 ldisc completion and fix the driver call race */
1381 wake_up_interruptible(&tty
->write_wait
);
1382 wake_up_interruptible(&tty
->read_wait
);
1385 * Shutdown the current line discipline, and reset it to
1388 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1389 tty_reset_termios(tty
);
1391 /* Defer ldisc switch */
1392 /* tty_deferred_ldisc_switch(N_TTY);
1394 This should get done automatically when the port closes and
1395 tty_release is called */
1397 read_lock(&tasklist_lock
);
1399 do_each_pid_task(tty
->session
, PIDTYPE_SID
, p
) {
1400 spin_lock_irq(&p
->sighand
->siglock
);
1401 if (p
->signal
->tty
== tty
)
1402 p
->signal
->tty
= NULL
;
1403 if (!p
->signal
->leader
) {
1404 spin_unlock_irq(&p
->sighand
->siglock
);
1407 __group_send_sig_info(SIGHUP
, SEND_SIG_PRIV
, p
);
1408 __group_send_sig_info(SIGCONT
, SEND_SIG_PRIV
, p
);
1409 put_pid(p
->signal
->tty_old_pgrp
); /* A noop */
1411 p
->signal
->tty_old_pgrp
= get_pid(tty
->pgrp
);
1412 spin_unlock_irq(&p
->sighand
->siglock
);
1413 } while_each_pid_task(tty
->session
, PIDTYPE_SID
, p
);
1415 read_unlock(&tasklist_lock
);
1418 put_pid(tty
->session
);
1420 tty
->session
= NULL
;
1422 tty
->ctrl_status
= 0;
1424 * If one of the devices matches a console pointer, we
1425 * cannot just call hangup() because that will cause
1426 * tty->count and state->count to go out of sync.
1427 * So we just call close() the right number of times.
1430 if (tty
->driver
->close
)
1431 for (n
= 0; n
< closecount
; n
++)
1432 tty
->driver
->close(tty
, cons_filp
);
1433 } else if (tty
->driver
->hangup
)
1434 (tty
->driver
->hangup
)(tty
);
1436 /* We don't want to have driver/ldisc interactions beyond
1437 the ones we did here. The driver layer expects no
1438 calls after ->hangup() from the ldisc side. However we
1439 can't yet guarantee all that */
1441 set_bit(TTY_HUPPED
, &tty
->flags
);
1443 tty_ldisc_enable(tty
);
1444 tty_ldisc_deref(ld
);
1452 * tty_hangup - trigger a hangup event
1453 * @tty: tty to hangup
1455 * A carrier loss (virtual or otherwise) has occurred on this like
1456 * schedule a hangup sequence to run after this event.
1459 void tty_hangup(struct tty_struct
* tty
)
1461 #ifdef TTY_DEBUG_HANGUP
1464 printk(KERN_DEBUG
"%s hangup...\n", tty_name(tty
, buf
));
1466 schedule_work(&tty
->hangup_work
);
1469 EXPORT_SYMBOL(tty_hangup
);
1472 * tty_vhangup - process vhangup
1473 * @tty: tty to hangup
1475 * The user has asked via system call for the terminal to be hung up.
1476 * We do this synchronously so that when the syscall returns the process
1477 * is complete. That guarantee is neccessary for security reasons.
1480 void tty_vhangup(struct tty_struct
* tty
)
1482 #ifdef TTY_DEBUG_HANGUP
1485 printk(KERN_DEBUG
"%s vhangup...\n", tty_name(tty
, buf
));
1487 do_tty_hangup(&tty
->hangup_work
);
1489 EXPORT_SYMBOL(tty_vhangup
);
1492 * tty_hung_up_p - was tty hung up
1493 * @filp: file pointer of tty
1495 * Return true if the tty has been subject to a vhangup or a carrier
1499 int tty_hung_up_p(struct file
* filp
)
1501 return (filp
->f_op
== &hung_up_tty_fops
);
1504 EXPORT_SYMBOL(tty_hung_up_p
);
1506 static void session_clear_tty(struct pid
*session
)
1508 struct task_struct
*p
;
1509 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
1511 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
1515 * disassociate_ctty - disconnect controlling tty
1516 * @on_exit: true if exiting so need to "hang up" the session
1518 * This function is typically called only by the session leader, when
1519 * it wants to disassociate itself from its controlling tty.
1521 * It performs the following functions:
1522 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
1523 * (2) Clears the tty from being controlling the session
1524 * (3) Clears the controlling tty for all processes in the
1527 * The argument on_exit is set to 1 if called when a process is
1528 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
1531 * BKL is taken for hysterical raisins
1532 * tty_mutex is taken to protect tty
1533 * ->siglock is taken to protect ->signal/->sighand
1534 * tasklist_lock is taken to walk process list for sessions
1535 * ->siglock is taken to protect ->signal/->sighand
1538 void disassociate_ctty(int on_exit
)
1540 struct tty_struct
*tty
;
1541 struct pid
*tty_pgrp
= NULL
;
1545 mutex_lock(&tty_mutex
);
1546 tty
= get_current_tty();
1548 tty_pgrp
= get_pid(tty
->pgrp
);
1549 mutex_unlock(&tty_mutex
);
1550 /* XXX: here we race, there is nothing protecting tty */
1551 if (on_exit
&& tty
->driver
->type
!= TTY_DRIVER_TYPE_PTY
)
1553 } else if (on_exit
) {
1554 struct pid
*old_pgrp
;
1555 spin_lock_irq(¤t
->sighand
->siglock
);
1556 old_pgrp
= current
->signal
->tty_old_pgrp
;
1557 current
->signal
->tty_old_pgrp
= NULL
;
1558 spin_unlock_irq(¤t
->sighand
->siglock
);
1560 kill_pgrp(old_pgrp
, SIGHUP
, on_exit
);
1561 kill_pgrp(old_pgrp
, SIGCONT
, on_exit
);
1564 mutex_unlock(&tty_mutex
);
1569 kill_pgrp(tty_pgrp
, SIGHUP
, on_exit
);
1571 kill_pgrp(tty_pgrp
, SIGCONT
, on_exit
);
1575 spin_lock_irq(¤t
->sighand
->siglock
);
1576 put_pid(current
->signal
->tty_old_pgrp
);
1577 current
->signal
->tty_old_pgrp
= NULL
;
1578 spin_unlock_irq(¤t
->sighand
->siglock
);
1580 mutex_lock(&tty_mutex
);
1581 /* It is possible that do_tty_hangup has free'd this tty */
1582 tty
= get_current_tty();
1584 put_pid(tty
->session
);
1586 tty
->session
= NULL
;
1589 #ifdef TTY_DEBUG_HANGUP
1590 printk(KERN_DEBUG
"error attempted to write to tty [0x%p]"
1594 mutex_unlock(&tty_mutex
);
1596 /* Now clear signal->tty under the lock */
1597 read_lock(&tasklist_lock
);
1598 session_clear_tty(task_session(current
));
1599 read_unlock(&tasklist_lock
);
1605 * no_tty - Ensure the current process does not have a controlling tty
1609 struct task_struct
*tsk
= current
;
1610 if (tsk
->signal
->leader
)
1611 disassociate_ctty(0);
1612 proc_clear_tty(tsk
);
1617 * stop_tty - propagate flow control
1620 * Perform flow control to the driver. For PTY/TTY pairs we
1621 * must also propagate the TIOCKPKT status. May be called
1622 * on an already stopped device and will not re-call the driver
1625 * This functionality is used by both the line disciplines for
1626 * halting incoming flow and by the driver. It may therefore be
1627 * called from any context, may be under the tty atomic_write_lock
1631 * Broken. Relies on BKL which is unsafe here.
1634 void stop_tty(struct tty_struct
*tty
)
1639 if (tty
->link
&& tty
->link
->packet
) {
1640 tty
->ctrl_status
&= ~TIOCPKT_START
;
1641 tty
->ctrl_status
|= TIOCPKT_STOP
;
1642 wake_up_interruptible(&tty
->link
->read_wait
);
1644 if (tty
->driver
->stop
)
1645 (tty
->driver
->stop
)(tty
);
1648 EXPORT_SYMBOL(stop_tty
);
1651 * start_tty - propagate flow control
1652 * @tty: tty to start
1654 * Start a tty that has been stopped if at all possible. Perform
1655 * any neccessary wakeups and propagate the TIOCPKT status. If this
1656 * is the tty was previous stopped and is being started then the
1657 * driver start method is invoked and the line discipline woken.
1660 * Broken. Relies on BKL which is unsafe here.
1663 void start_tty(struct tty_struct
*tty
)
1665 if (!tty
->stopped
|| tty
->flow_stopped
)
1668 if (tty
->link
&& tty
->link
->packet
) {
1669 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
1670 tty
->ctrl_status
|= TIOCPKT_START
;
1671 wake_up_interruptible(&tty
->link
->read_wait
);
1673 if (tty
->driver
->start
)
1674 (tty
->driver
->start
)(tty
);
1676 /* If we have a running line discipline it may need kicking */
1680 EXPORT_SYMBOL(start_tty
);
1683 * tty_read - read method for tty device files
1684 * @file: pointer to tty file
1686 * @count: size of user buffer
1689 * Perform the read system call function on this terminal device. Checks
1690 * for hung up devices before calling the line discipline method.
1693 * Locks the line discipline internally while needed
1694 * For historical reasons the line discipline read method is
1695 * invoked under the BKL. This will go away in time so do not rely on it
1696 * in new code. Multiple read calls may be outstanding in parallel.
1699 static ssize_t
tty_read(struct file
* file
, char __user
* buf
, size_t count
,
1703 struct tty_struct
* tty
;
1704 struct inode
*inode
;
1705 struct tty_ldisc
*ld
;
1707 tty
= (struct tty_struct
*)file
->private_data
;
1708 inode
= file
->f_path
.dentry
->d_inode
;
1709 if (tty_paranoia_check(tty
, inode
, "tty_read"))
1711 if (!tty
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1714 /* We want to wait for the line discipline to sort out in this
1716 ld
= tty_ldisc_ref_wait(tty
);
1719 i
= (ld
->read
)(tty
,file
,buf
,count
);
1722 tty_ldisc_deref(ld
);
1725 inode
->i_atime
= current_fs_time(inode
->i_sb
);
1730 * Split writes up in sane blocksizes to avoid
1731 * denial-of-service type attacks
1733 static inline ssize_t
do_tty_write(
1734 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
1735 struct tty_struct
*tty
,
1737 const char __user
*buf
,
1740 ssize_t ret
= 0, written
= 0;
1743 /* FIXME: O_NDELAY ... */
1744 if (mutex_lock_interruptible(&tty
->atomic_write_lock
)) {
1745 return -ERESTARTSYS
;
1749 * We chunk up writes into a temporary buffer. This
1750 * simplifies low-level drivers immensely, since they
1751 * don't have locking issues and user mode accesses.
1753 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1756 * The default chunk-size is 2kB, because the NTTY
1757 * layer has problems with bigger chunks. It will
1758 * claim to be able to handle more characters than
1761 * FIXME: This can probably go away now except that 64K chunks
1762 * are too likely to fail unless switched to vmalloc...
1765 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
1770 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1771 if (tty
->write_cnt
< chunk
) {
1777 buf
= kmalloc(chunk
, GFP_KERNEL
);
1779 mutex_unlock(&tty
->atomic_write_lock
);
1782 kfree(tty
->write_buf
);
1783 tty
->write_cnt
= chunk
;
1784 tty
->write_buf
= buf
;
1787 /* Do the write .. */
1789 size_t size
= count
;
1793 if (copy_from_user(tty
->write_buf
, buf
, size
))
1796 ret
= write(tty
, file
, tty
->write_buf
, size
);
1806 if (signal_pending(current
))
1811 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1812 inode
->i_mtime
= current_fs_time(inode
->i_sb
);
1815 mutex_unlock(&tty
->atomic_write_lock
);
1821 * tty_write - write method for tty device file
1822 * @file: tty file pointer
1823 * @buf: user data to write
1824 * @count: bytes to write
1827 * Write data to a tty device via the line discipline.
1830 * Locks the line discipline as required
1831 * Writes to the tty driver are serialized by the atomic_write_lock
1832 * and are then processed in chunks to the device. The line discipline
1833 * write method will not be involked in parallel for each device
1834 * The line discipline write method is called under the big
1835 * kernel lock for historical reasons. New code should not rely on this.
1838 static ssize_t
tty_write(struct file
* file
, const char __user
* buf
, size_t count
,
1841 struct tty_struct
* tty
;
1842 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1844 struct tty_ldisc
*ld
;
1846 tty
= (struct tty_struct
*)file
->private_data
;
1847 if (tty_paranoia_check(tty
, inode
, "tty_write"))
1849 if (!tty
|| !tty
->driver
->write
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1852 ld
= tty_ldisc_ref_wait(tty
);
1856 ret
= do_tty_write(ld
->write
, tty
, file
, buf
, count
);
1857 tty_ldisc_deref(ld
);
1861 ssize_t
redirected_tty_write(struct file
* file
, const char __user
* buf
, size_t count
,
1864 struct file
*p
= NULL
;
1866 spin_lock(&redirect_lock
);
1871 spin_unlock(&redirect_lock
);
1875 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1880 return tty_write(file
, buf
, count
, ppos
);
1883 static char ptychar
[] = "pqrstuvwxyzabcde";
1886 * pty_line_name - generate name for a pty
1887 * @driver: the tty driver in use
1888 * @index: the minor number
1889 * @p: output buffer of at least 6 bytes
1891 * Generate a name from a driver reference and write it to the output
1896 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1898 int i
= index
+ driver
->name_base
;
1899 /* ->name is initialized to "ttyp", but "tty" is expected */
1900 sprintf(p
, "%s%c%x",
1901 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1902 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1906 * pty_line_name - generate name for a tty
1907 * @driver: the tty driver in use
1908 * @index: the minor number
1909 * @p: output buffer of at least 7 bytes
1911 * Generate a name from a driver reference and write it to the output
1916 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1918 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
1922 * init_dev - initialise a tty device
1923 * @driver: tty driver we are opening a device on
1924 * @idx: device index
1925 * @tty: returned tty structure
1927 * Prepare a tty device. This may not be a "new" clean device but
1928 * could also be an active device. The pty drivers require special
1929 * handling because of this.
1932 * The function is called under the tty_mutex, which
1933 * protects us from the tty struct or driver itself going away.
1935 * On exit the tty device has the line discipline attached and
1936 * a reference count of 1. If a pair was created for pty/tty use
1937 * and the other was a pty master then it too has a reference count of 1.
1939 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1940 * failed open. The new code protects the open with a mutex, so it's
1941 * really quite straightforward. The mutex locking can probably be
1942 * relaxed for the (most common) case of reopening a tty.
1945 static int init_dev(struct tty_driver
*driver
, int idx
,
1946 struct tty_struct
**ret_tty
)
1948 struct tty_struct
*tty
, *o_tty
;
1949 struct ktermios
*tp
, **tp_loc
, *o_tp
, **o_tp_loc
;
1950 struct ktermios
*ltp
, **ltp_loc
, *o_ltp
, **o_ltp_loc
;
1953 /* check whether we're reopening an existing tty */
1954 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
1955 tty
= devpts_get_tty(idx
);
1957 * If we don't have a tty here on a slave open, it's because
1958 * the master already started the close process and there's
1959 * no relation between devpts file and tty anymore.
1961 if (!tty
&& driver
->subtype
== PTY_TYPE_SLAVE
) {
1966 * It's safe from now on because init_dev() is called with
1967 * tty_mutex held and release_dev() won't change tty->count
1968 * or tty->flags without having to grab tty_mutex
1970 if (tty
&& driver
->subtype
== PTY_TYPE_MASTER
)
1973 tty
= driver
->ttys
[idx
];
1975 if (tty
) goto fast_track
;
1978 * First time open is complex, especially for PTY devices.
1979 * This code guarantees that either everything succeeds and the
1980 * TTY is ready for operation, or else the table slots are vacated
1981 * and the allocated memory released. (Except that the termios
1982 * and locked termios may be retained.)
1985 if (!try_module_get(driver
->owner
)) {
1994 tty
= alloc_tty_struct();
1997 initialize_tty_struct(tty
);
1998 tty
->driver
= driver
;
2000 tty_line_name(driver
, idx
, tty
->name
);
2002 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
2003 tp_loc
= &tty
->termios
;
2004 ltp_loc
= &tty
->termios_locked
;
2006 tp_loc
= &driver
->termios
[idx
];
2007 ltp_loc
= &driver
->termios_locked
[idx
];
2011 tp
= (struct ktermios
*) kmalloc(sizeof(struct ktermios
),
2015 *tp
= driver
->init_termios
;
2019 ltp
= (struct ktermios
*) kmalloc(sizeof(struct ktermios
),
2023 memset(ltp
, 0, sizeof(struct ktermios
));
2026 if (driver
->type
== TTY_DRIVER_TYPE_PTY
) {
2027 o_tty
= alloc_tty_struct();
2030 initialize_tty_struct(o_tty
);
2031 o_tty
->driver
= driver
->other
;
2033 tty_line_name(driver
->other
, idx
, o_tty
->name
);
2035 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
2036 o_tp_loc
= &o_tty
->termios
;
2037 o_ltp_loc
= &o_tty
->termios_locked
;
2039 o_tp_loc
= &driver
->other
->termios
[idx
];
2040 o_ltp_loc
= &driver
->other
->termios_locked
[idx
];
2044 o_tp
= (struct ktermios
*)
2045 kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
2048 *o_tp
= driver
->other
->init_termios
;
2052 o_ltp
= (struct ktermios
*)
2053 kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
2056 memset(o_ltp
, 0, sizeof(struct ktermios
));
2060 * Everything allocated ... set up the o_tty structure.
2062 if (!(driver
->other
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2063 driver
->other
->ttys
[idx
] = o_tty
;
2069 o_tty
->termios
= *o_tp_loc
;
2070 o_tty
->termios_locked
= *o_ltp_loc
;
2071 driver
->other
->refcount
++;
2072 if (driver
->subtype
== PTY_TYPE_MASTER
)
2075 /* Establish the links in both directions */
2081 * All structures have been allocated, so now we install them.
2082 * Failures after this point use release_tty to clean up, so
2083 * there's no need to null out the local pointers.
2085 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2086 driver
->ttys
[idx
] = tty
;
2093 tty
->termios
= *tp_loc
;
2094 tty
->termios_locked
= *ltp_loc
;
2095 /* Compatibility until drivers always set this */
2096 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
2097 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
2102 * Structures all installed ... call the ldisc open routines.
2103 * If we fail here just call release_tty to clean up. No need
2104 * to decrement the use counts, as release_tty doesn't care.
2107 if (tty
->ldisc
.open
) {
2108 retval
= (tty
->ldisc
.open
)(tty
);
2110 goto release_mem_out
;
2112 if (o_tty
&& o_tty
->ldisc
.open
) {
2113 retval
= (o_tty
->ldisc
.open
)(o_tty
);
2115 if (tty
->ldisc
.close
)
2116 (tty
->ldisc
.close
)(tty
);
2117 goto release_mem_out
;
2119 tty_ldisc_enable(o_tty
);
2121 tty_ldisc_enable(tty
);
2125 * This fast open can be used if the tty is already open.
2126 * No memory is allocated, and the only failures are from
2127 * attempting to open a closing tty or attempting multiple
2128 * opens on a pty master.
2131 if (test_bit(TTY_CLOSING
, &tty
->flags
)) {
2135 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2136 driver
->subtype
== PTY_TYPE_MASTER
) {
2138 * special case for PTY masters: only one open permitted,
2139 * and the slave side open count is incremented as well.
2148 tty
->driver
= driver
; /* N.B. why do this every time?? */
2151 if(!test_bit(TTY_LDISC
, &tty
->flags
))
2152 printk(KERN_ERR
"init_dev but no ldisc\n");
2156 /* All paths come through here to release the mutex */
2160 /* Release locally allocated memory ... nothing placed in slots */
2164 free_tty_struct(o_tty
);
2167 free_tty_struct(tty
);
2170 module_put(driver
->owner
);
2174 /* call the tty release_tty routine to clean out this slot */
2176 if (printk_ratelimit())
2177 printk(KERN_INFO
"init_dev: ldisc open failed, "
2178 "clearing slot %d\n", idx
);
2179 release_tty(tty
, idx
);
2184 * release_one_tty - release tty structure memory
2186 * Releases memory associated with a tty structure, and clears out the
2187 * driver table slots. This function is called when a device is no longer
2188 * in use. It also gets called when setup of a device fails.
2191 * tty_mutex - sometimes only
2192 * takes the file list lock internally when working on the list
2193 * of ttys that the driver keeps.
2194 * FIXME: should we require tty_mutex is held here ??
2196 static void release_one_tty(struct tty_struct
*tty
, int idx
)
2198 int devpts
= tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
;
2199 struct ktermios
*tp
;
2202 tty
->driver
->ttys
[idx
] = NULL
;
2204 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
) {
2207 tty
->driver
->termios
[idx
] = NULL
;
2210 tp
= tty
->termios_locked
;
2212 tty
->driver
->termios_locked
[idx
] = NULL
;
2218 tty
->driver
->refcount
--;
2221 list_del_init(&tty
->tty_files
);
2224 free_tty_struct(tty
);
2228 * release_tty - release tty structure memory
2230 * Release both @tty and a possible linked partner (think pty pair),
2231 * and decrement the refcount of the backing module.
2234 * tty_mutex - sometimes only
2235 * takes the file list lock internally when working on the list
2236 * of ttys that the driver keeps.
2237 * FIXME: should we require tty_mutex is held here ??
2239 static void release_tty(struct tty_struct
*tty
, int idx
)
2241 struct tty_driver
*driver
= tty
->driver
;
2244 release_one_tty(tty
->link
, idx
);
2245 release_one_tty(tty
, idx
);
2246 module_put(driver
->owner
);
2250 * Even releasing the tty structures is a tricky business.. We have
2251 * to be very careful that the structures are all released at the
2252 * same time, as interrupts might otherwise get the wrong pointers.
2254 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
2255 * lead to double frees or releasing memory still in use.
2257 static void release_dev(struct file
* filp
)
2259 struct tty_struct
*tty
, *o_tty
;
2260 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
2264 unsigned long flags
;
2266 tty
= (struct tty_struct
*)filp
->private_data
;
2267 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "release_dev"))
2270 check_tty_count(tty
, "release_dev");
2272 tty_fasync(-1, filp
, 0);
2275 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2276 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
2277 devpts
= (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) != 0;
2280 #ifdef TTY_PARANOIA_CHECK
2281 if (idx
< 0 || idx
>= tty
->driver
->num
) {
2282 printk(KERN_DEBUG
"release_dev: bad idx when trying to "
2283 "free (%s)\n", tty
->name
);
2286 if (!(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2287 if (tty
!= tty
->driver
->ttys
[idx
]) {
2288 printk(KERN_DEBUG
"release_dev: driver.table[%d] not tty "
2289 "for (%s)\n", idx
, tty
->name
);
2292 if (tty
->termios
!= tty
->driver
->termios
[idx
]) {
2293 printk(KERN_DEBUG
"release_dev: driver.termios[%d] not termios "
2298 if (tty
->termios_locked
!= tty
->driver
->termios_locked
[idx
]) {
2299 printk(KERN_DEBUG
"release_dev: driver.termios_locked[%d] not "
2300 "termios_locked for (%s)\n",
2307 #ifdef TTY_DEBUG_HANGUP
2308 printk(KERN_DEBUG
"release_dev of %s (tty count=%d)...",
2309 tty_name(tty
, buf
), tty
->count
);
2312 #ifdef TTY_PARANOIA_CHECK
2313 if (tty
->driver
->other
&&
2314 !(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2315 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
2316 printk(KERN_DEBUG
"release_dev: other->table[%d] "
2317 "not o_tty for (%s)\n",
2321 if (o_tty
->termios
!= tty
->driver
->other
->termios
[idx
]) {
2322 printk(KERN_DEBUG
"release_dev: other->termios[%d] "
2323 "not o_termios for (%s)\n",
2327 if (o_tty
->termios_locked
!=
2328 tty
->driver
->other
->termios_locked
[idx
]) {
2329 printk(KERN_DEBUG
"release_dev: other->termios_locked["
2330 "%d] not o_termios_locked for (%s)\n",
2334 if (o_tty
->link
!= tty
) {
2335 printk(KERN_DEBUG
"release_dev: bad pty pointers\n");
2340 if (tty
->driver
->close
)
2341 tty
->driver
->close(tty
, filp
);
2344 * Sanity check: if tty->count is going to zero, there shouldn't be
2345 * any waiters on tty->read_wait or tty->write_wait. We test the
2346 * wait queues and kick everyone out _before_ actually starting to
2347 * close. This ensures that we won't block while releasing the tty
2350 * The test for the o_tty closing is necessary, since the master and
2351 * slave sides may close in any order. If the slave side closes out
2352 * first, its count will be one, since the master side holds an open.
2353 * Thus this test wouldn't be triggered at the time the slave closes,
2356 * Note that it's possible for the tty to be opened again while we're
2357 * flushing out waiters. By recalculating the closing flags before
2358 * each iteration we avoid any problems.
2361 /* Guard against races with tty->count changes elsewhere and
2362 opens on /dev/tty */
2364 mutex_lock(&tty_mutex
);
2365 tty_closing
= tty
->count
<= 1;
2366 o_tty_closing
= o_tty
&&
2367 (o_tty
->count
<= (pty_master
? 1 : 0));
2371 if (waitqueue_active(&tty
->read_wait
)) {
2372 wake_up(&tty
->read_wait
);
2375 if (waitqueue_active(&tty
->write_wait
)) {
2376 wake_up(&tty
->write_wait
);
2380 if (o_tty_closing
) {
2381 if (waitqueue_active(&o_tty
->read_wait
)) {
2382 wake_up(&o_tty
->read_wait
);
2385 if (waitqueue_active(&o_tty
->write_wait
)) {
2386 wake_up(&o_tty
->write_wait
);
2393 printk(KERN_WARNING
"release_dev: %s: read/write wait queue "
2394 "active!\n", tty_name(tty
, buf
));
2395 mutex_unlock(&tty_mutex
);
2400 * The closing flags are now consistent with the open counts on
2401 * both sides, and we've completed the last operation that could
2402 * block, so it's safe to proceed with closing.
2405 if (--o_tty
->count
< 0) {
2406 printk(KERN_WARNING
"release_dev: bad pty slave count "
2408 o_tty
->count
, tty_name(o_tty
, buf
));
2412 if (--tty
->count
< 0) {
2413 printk(KERN_WARNING
"release_dev: bad tty->count (%d) for %s\n",
2414 tty
->count
, tty_name(tty
, buf
));
2419 * We've decremented tty->count, so we need to remove this file
2420 * descriptor off the tty->tty_files list; this serves two
2422 * - check_tty_count sees the correct number of file descriptors
2423 * associated with this tty.
2424 * - do_tty_hangup no longer sees this file descriptor as
2425 * something that needs to be handled for hangups.
2428 filp
->private_data
= NULL
;
2431 * Perform some housekeeping before deciding whether to return.
2433 * Set the TTY_CLOSING flag if this was the last open. In the
2434 * case of a pty we may have to wait around for the other side
2435 * to close, and TTY_CLOSING makes sure we can't be reopened.
2438 set_bit(TTY_CLOSING
, &tty
->flags
);
2440 set_bit(TTY_CLOSING
, &o_tty
->flags
);
2443 * If _either_ side is closing, make sure there aren't any
2444 * processes that still think tty or o_tty is their controlling
2447 if (tty_closing
|| o_tty_closing
) {
2448 read_lock(&tasklist_lock
);
2449 session_clear_tty(tty
->session
);
2451 session_clear_tty(o_tty
->session
);
2452 read_unlock(&tasklist_lock
);
2455 mutex_unlock(&tty_mutex
);
2457 /* check whether both sides are closing ... */
2458 if (!tty_closing
|| (o_tty
&& !o_tty_closing
))
2461 #ifdef TTY_DEBUG_HANGUP
2462 printk(KERN_DEBUG
"freeing tty structure...");
2465 * Prevent flush_to_ldisc() from rescheduling the work for later. Then
2466 * kill any delayed work. As this is the final close it does not
2467 * race with the set_ldisc code path.
2469 clear_bit(TTY_LDISC
, &tty
->flags
);
2470 cancel_delayed_work(&tty
->buf
.work
);
2473 * Wait for ->hangup_work and ->buf.work handlers to terminate
2476 flush_scheduled_work();
2479 * Wait for any short term users (we know they are just driver
2480 * side waiters as the file is closing so user count on the file
2483 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
2484 while(tty
->ldisc
.refcount
)
2486 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
2487 wait_event(tty_ldisc_wait
, tty
->ldisc
.refcount
== 0);
2488 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
2490 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
2492 * Shutdown the current line discipline, and reset it to N_TTY.
2493 * N.B. why reset ldisc when we're releasing the memory??
2495 * FIXME: this MUST get fixed for the new reflocking
2497 if (tty
->ldisc
.close
)
2498 (tty
->ldisc
.close
)(tty
);
2499 tty_ldisc_put(tty
->ldisc
.num
);
2502 * Switch the line discipline back
2504 tty_ldisc_assign(tty
, tty_ldisc_get(N_TTY
));
2505 tty_set_termios_ldisc(tty
,N_TTY
);
2507 /* FIXME: could o_tty be in setldisc here ? */
2508 clear_bit(TTY_LDISC
, &o_tty
->flags
);
2509 if (o_tty
->ldisc
.close
)
2510 (o_tty
->ldisc
.close
)(o_tty
);
2511 tty_ldisc_put(o_tty
->ldisc
.num
);
2512 tty_ldisc_assign(o_tty
, tty_ldisc_get(N_TTY
));
2513 tty_set_termios_ldisc(o_tty
,N_TTY
);
2516 * The release_tty function takes care of the details of clearing
2517 * the slots and preserving the termios structure.
2519 release_tty(tty
, idx
);
2521 #ifdef CONFIG_UNIX98_PTYS
2522 /* Make this pty number available for reallocation */
2524 down(&allocated_ptys_lock
);
2525 idr_remove(&allocated_ptys
, idx
);
2526 up(&allocated_ptys_lock
);
2533 * tty_open - open a tty device
2534 * @inode: inode of device file
2535 * @filp: file pointer to tty
2537 * tty_open and tty_release keep up the tty count that contains the
2538 * number of opens done on a tty. We cannot use the inode-count, as
2539 * different inodes might point to the same tty.
2541 * Open-counting is needed for pty masters, as well as for keeping
2542 * track of serial lines: DTR is dropped when the last close happens.
2543 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2545 * The termios state of a pty is reset on first open so that
2546 * settings don't persist across reuse.
2548 * Locking: tty_mutex protects tty, get_tty_driver and init_dev work.
2549 * tty->count should protect the rest.
2550 * ->siglock protects ->signal/->sighand
2553 static int tty_open(struct inode
* inode
, struct file
* filp
)
2555 struct tty_struct
*tty
;
2557 struct tty_driver
*driver
;
2559 dev_t device
= inode
->i_rdev
;
2560 unsigned short saved_flags
= filp
->f_flags
;
2562 nonseekable_open(inode
, filp
);
2565 noctty
= filp
->f_flags
& O_NOCTTY
;
2569 mutex_lock(&tty_mutex
);
2571 if (device
== MKDEV(TTYAUX_MAJOR
,0)) {
2572 tty
= get_current_tty();
2574 mutex_unlock(&tty_mutex
);
2577 driver
= tty
->driver
;
2579 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
2584 if (device
== MKDEV(TTY_MAJOR
,0)) {
2585 extern struct tty_driver
*console_driver
;
2586 driver
= console_driver
;
2592 if (device
== MKDEV(TTYAUX_MAJOR
,1)) {
2593 driver
= console_device(&index
);
2595 /* Don't let /dev/console block */
2596 filp
->f_flags
|= O_NONBLOCK
;
2600 mutex_unlock(&tty_mutex
);
2604 driver
= get_tty_driver(device
, &index
);
2606 mutex_unlock(&tty_mutex
);
2610 retval
= init_dev(driver
, index
, &tty
);
2611 mutex_unlock(&tty_mutex
);
2615 filp
->private_data
= tty
;
2616 file_move(filp
, &tty
->tty_files
);
2617 check_tty_count(tty
, "tty_open");
2618 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2619 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2621 #ifdef TTY_DEBUG_HANGUP
2622 printk(KERN_DEBUG
"opening %s...", tty
->name
);
2625 if (tty
->driver
->open
)
2626 retval
= tty
->driver
->open(tty
, filp
);
2630 filp
->f_flags
= saved_flags
;
2632 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) && !capable(CAP_SYS_ADMIN
))
2636 #ifdef TTY_DEBUG_HANGUP
2637 printk(KERN_DEBUG
"error %d in opening %s...", retval
,
2641 if (retval
!= -ERESTARTSYS
)
2643 if (signal_pending(current
))
2647 * Need to reset f_op in case a hangup happened.
2649 if (filp
->f_op
== &hung_up_tty_fops
)
2650 filp
->f_op
= &tty_fops
;
2654 mutex_lock(&tty_mutex
);
2655 spin_lock_irq(¤t
->sighand
->siglock
);
2657 current
->signal
->leader
&&
2658 !current
->signal
->tty
&&
2659 tty
->session
== NULL
)
2660 __proc_set_tty(current
, tty
);
2661 spin_unlock_irq(¤t
->sighand
->siglock
);
2662 mutex_unlock(&tty_mutex
);
2666 #ifdef CONFIG_UNIX98_PTYS
2668 * ptmx_open - open a unix 98 pty master
2669 * @inode: inode of device file
2670 * @filp: file pointer to tty
2672 * Allocate a unix98 pty master device from the ptmx driver.
2674 * Locking: tty_mutex protects theinit_dev work. tty->count should
2676 * allocated_ptys_lock handles the list of free pty numbers
2679 static int ptmx_open(struct inode
* inode
, struct file
* filp
)
2681 struct tty_struct
*tty
;
2686 nonseekable_open(inode
, filp
);
2688 /* find a device that is not in use. */
2689 down(&allocated_ptys_lock
);
2690 if (!idr_pre_get(&allocated_ptys
, GFP_KERNEL
)) {
2691 up(&allocated_ptys_lock
);
2694 idr_ret
= idr_get_new(&allocated_ptys
, NULL
, &index
);
2696 up(&allocated_ptys_lock
);
2697 if (idr_ret
== -EAGAIN
)
2701 if (index
>= pty_limit
) {
2702 idr_remove(&allocated_ptys
, index
);
2703 up(&allocated_ptys_lock
);
2706 up(&allocated_ptys_lock
);
2708 mutex_lock(&tty_mutex
);
2709 retval
= init_dev(ptm_driver
, index
, &tty
);
2710 mutex_unlock(&tty_mutex
);
2715 set_bit(TTY_PTY_LOCK
, &tty
->flags
); /* LOCK THE SLAVE */
2716 filp
->private_data
= tty
;
2717 file_move(filp
, &tty
->tty_files
);
2720 if (devpts_pty_new(tty
->link
))
2723 check_tty_count(tty
, "tty_open");
2724 retval
= ptm_driver
->open(tty
, filp
);
2731 down(&allocated_ptys_lock
);
2732 idr_remove(&allocated_ptys
, index
);
2733 up(&allocated_ptys_lock
);
2739 * tty_release - vfs callback for close
2740 * @inode: inode of tty
2741 * @filp: file pointer for handle to tty
2743 * Called the last time each file handle is closed that references
2744 * this tty. There may however be several such references.
2747 * Takes bkl. See release_dev
2750 static int tty_release(struct inode
* inode
, struct file
* filp
)
2759 * tty_poll - check tty status
2760 * @filp: file being polled
2761 * @wait: poll wait structures to update
2763 * Call the line discipline polling method to obtain the poll
2764 * status of the device.
2766 * Locking: locks called line discipline but ldisc poll method
2767 * may be re-entered freely by other callers.
2770 static unsigned int tty_poll(struct file
* filp
, poll_table
* wait
)
2772 struct tty_struct
* tty
;
2773 struct tty_ldisc
*ld
;
2776 tty
= (struct tty_struct
*)filp
->private_data
;
2777 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
2780 ld
= tty_ldisc_ref_wait(tty
);
2782 ret
= (ld
->poll
)(tty
, filp
, wait
);
2783 tty_ldisc_deref(ld
);
2787 static int tty_fasync(int fd
, struct file
* filp
, int on
)
2789 struct tty_struct
* tty
;
2792 tty
= (struct tty_struct
*)filp
->private_data
;
2793 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
2796 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2803 if (!waitqueue_active(&tty
->read_wait
))
2804 tty
->minimum_to_wake
= 1;
2807 type
= PIDTYPE_PGID
;
2809 pid
= task_pid(current
);
2812 retval
= __f_setown(filp
, pid
, type
, 0);
2816 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
2817 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
2823 * tiocsti - fake input character
2824 * @tty: tty to fake input into
2825 * @p: pointer to character
2827 * Fake input to a tty device. Does the neccessary locking and
2830 * FIXME: does not honour flow control ??
2833 * Called functions take tty_ldisc_lock
2834 * current->signal->tty check is safe without locks
2836 * FIXME: may race normal receive processing
2839 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2842 struct tty_ldisc
*ld
;
2844 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2846 if (get_user(ch
, p
))
2848 ld
= tty_ldisc_ref_wait(tty
);
2849 ld
->receive_buf(tty
, &ch
, &mbz
, 1);
2850 tty_ldisc_deref(ld
);
2855 * tiocgwinsz - implement window query ioctl
2857 * @arg: user buffer for result
2859 * Copies the kernel idea of the window size into the user buffer.
2861 * Locking: tty->termios_mutex is taken to ensure the winsize data
2865 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
* arg
)
2869 mutex_lock(&tty
->termios_mutex
);
2870 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2871 mutex_unlock(&tty
->termios_mutex
);
2873 return err
? -EFAULT
: 0;
2877 * tiocswinsz - implement window size set ioctl
2879 * @arg: user buffer for result
2881 * Copies the user idea of the window size to the kernel. Traditionally
2882 * this is just advisory information but for the Linux console it
2883 * actually has driver level meaning and triggers a VC resize.
2886 * Called function use the console_sem is used to ensure we do
2887 * not try and resize the console twice at once.
2888 * The tty->termios_mutex is used to ensure we don't double
2889 * resize and get confused. Lock order - tty->termios_mutex before
2893 static int tiocswinsz(struct tty_struct
*tty
, struct tty_struct
*real_tty
,
2894 struct winsize __user
* arg
)
2896 struct winsize tmp_ws
;
2898 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2901 mutex_lock(&tty
->termios_mutex
);
2902 if (!memcmp(&tmp_ws
, &tty
->winsize
, sizeof(*arg
)))
2906 if (tty
->driver
->type
== TTY_DRIVER_TYPE_CONSOLE
) {
2907 if (vc_lock_resize(tty
->driver_data
, tmp_ws
.ws_col
,
2909 mutex_unlock(&tty
->termios_mutex
);
2915 kill_pgrp(tty
->pgrp
, SIGWINCH
, 1);
2916 if ((real_tty
->pgrp
!= tty
->pgrp
) && real_tty
->pgrp
)
2917 kill_pgrp(real_tty
->pgrp
, SIGWINCH
, 1);
2918 tty
->winsize
= tmp_ws
;
2919 real_tty
->winsize
= tmp_ws
;
2921 mutex_unlock(&tty
->termios_mutex
);
2926 * tioccons - allow admin to move logical console
2927 * @file: the file to become console
2929 * Allow the adminstrator to move the redirected console device
2931 * Locking: uses redirect_lock to guard the redirect information
2934 static int tioccons(struct file
*file
)
2936 if (!capable(CAP_SYS_ADMIN
))
2938 if (file
->f_op
->write
== redirected_tty_write
) {
2940 spin_lock(&redirect_lock
);
2943 spin_unlock(&redirect_lock
);
2948 spin_lock(&redirect_lock
);
2950 spin_unlock(&redirect_lock
);
2955 spin_unlock(&redirect_lock
);
2960 * fionbio - non blocking ioctl
2961 * @file: file to set blocking value
2962 * @p: user parameter
2964 * Historical tty interfaces had a blocking control ioctl before
2965 * the generic functionality existed. This piece of history is preserved
2966 * in the expected tty API of posix OS's.
2968 * Locking: none, the open fle handle ensures it won't go away.
2971 static int fionbio(struct file
*file
, int __user
*p
)
2975 if (get_user(nonblock
, p
))
2979 file
->f_flags
|= O_NONBLOCK
;
2981 file
->f_flags
&= ~O_NONBLOCK
;
2986 * tiocsctty - set controlling tty
2987 * @tty: tty structure
2988 * @arg: user argument
2990 * This ioctl is used to manage job control. It permits a session
2991 * leader to set this tty as the controlling tty for the session.
2994 * Takes tty_mutex() to protect tty instance
2995 * Takes tasklist_lock internally to walk sessions
2996 * Takes ->siglock() when updating signal->tty
2999 static int tiocsctty(struct tty_struct
*tty
, int arg
)
3002 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
3005 mutex_lock(&tty_mutex
);
3007 * The process must be a session leader and
3008 * not have a controlling tty already.
3010 if (!current
->signal
->leader
|| current
->signal
->tty
) {
3017 * This tty is already the controlling
3018 * tty for another session group!
3020 if ((arg
== 1) && capable(CAP_SYS_ADMIN
)) {
3024 read_lock(&tasklist_lock
);
3025 session_clear_tty(tty
->session
);
3026 read_unlock(&tasklist_lock
);
3032 proc_set_tty(current
, tty
);
3034 mutex_unlock(&tty_mutex
);
3039 * tiocgpgrp - get process group
3040 * @tty: tty passed by user
3041 * @real_tty: tty side of the tty pased by the user if a pty else the tty
3044 * Obtain the process group of the tty. If there is no process group
3047 * Locking: none. Reference to current->signal->tty is safe.
3050 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3053 * (tty == real_tty) is a cheap way of
3054 * testing if the tty is NOT a master pty.
3056 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
3058 return put_user(pid_nr(real_tty
->pgrp
), p
);
3062 * tiocspgrp - attempt to set process group
3063 * @tty: tty passed by user
3064 * @real_tty: tty side device matching tty passed by user
3067 * Set the process group of the tty to the session passed. Only
3068 * permitted where the tty session is our session.
3073 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3077 int retval
= tty_check_change(real_tty
);
3083 if (!current
->signal
->tty
||
3084 (current
->signal
->tty
!= real_tty
) ||
3085 (real_tty
->session
!= task_session(current
)))
3087 if (get_user(pgrp_nr
, p
))
3092 pgrp
= find_pid(pgrp_nr
);
3097 if (session_of_pgrp(pgrp
) != task_session(current
))
3100 put_pid(real_tty
->pgrp
);
3101 real_tty
->pgrp
= get_pid(pgrp
);
3108 * tiocgsid - get session id
3109 * @tty: tty passed by user
3110 * @real_tty: tty side of the tty pased by the user if a pty else the tty
3111 * @p: pointer to returned session id
3113 * Obtain the session id of the tty. If there is no session
3116 * Locking: none. Reference to current->signal->tty is safe.
3119 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3122 * (tty == real_tty) is a cheap way of
3123 * testing if the tty is NOT a master pty.
3125 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
3127 if (!real_tty
->session
)
3129 return put_user(pid_nr(real_tty
->session
), p
);
3133 * tiocsetd - set line discipline
3135 * @p: pointer to user data
3137 * Set the line discipline according to user request.
3139 * Locking: see tty_set_ldisc, this function is just a helper
3142 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
3146 if (get_user(ldisc
, p
))
3148 return tty_set_ldisc(tty
, ldisc
);
3152 * send_break - performed time break
3153 * @tty: device to break on
3154 * @duration: timeout in mS
3156 * Perform a timed break on hardware that lacks its own driver level
3157 * timed break functionality.
3160 * atomic_write_lock serializes
3164 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
3166 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
3168 tty
->driver
->break_ctl(tty
, -1);
3169 if (!signal_pending(current
)) {
3170 msleep_interruptible(duration
);
3172 tty
->driver
->break_ctl(tty
, 0);
3173 mutex_unlock(&tty
->atomic_write_lock
);
3174 if (signal_pending(current
))
3180 * tiocmget - get modem status
3182 * @file: user file pointer
3183 * @p: pointer to result
3185 * Obtain the modem status bits from the tty driver if the feature
3186 * is supported. Return -EINVAL if it is not available.
3188 * Locking: none (up to the driver)
3191 static int tty_tiocmget(struct tty_struct
*tty
, struct file
*file
, int __user
*p
)
3193 int retval
= -EINVAL
;
3195 if (tty
->driver
->tiocmget
) {
3196 retval
= tty
->driver
->tiocmget(tty
, file
);
3199 retval
= put_user(retval
, p
);
3205 * tiocmset - set modem status
3207 * @file: user file pointer
3208 * @cmd: command - clear bits, set bits or set all
3209 * @p: pointer to desired bits
3211 * Set the modem status bits from the tty driver if the feature
3212 * is supported. Return -EINVAL if it is not available.
3214 * Locking: none (up to the driver)
3217 static int tty_tiocmset(struct tty_struct
*tty
, struct file
*file
, unsigned int cmd
,
3220 int retval
= -EINVAL
;
3222 if (tty
->driver
->tiocmset
) {
3223 unsigned int set
, clear
, val
;
3225 retval
= get_user(val
, p
);
3243 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
3244 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
3246 retval
= tty
->driver
->tiocmset(tty
, file
, set
, clear
);
3252 * Split this up, as gcc can choke on it otherwise..
3254 int tty_ioctl(struct inode
* inode
, struct file
* file
,
3255 unsigned int cmd
, unsigned long arg
)
3257 struct tty_struct
*tty
, *real_tty
;
3258 void __user
*p
= (void __user
*)arg
;
3260 struct tty_ldisc
*ld
;
3262 tty
= (struct tty_struct
*)file
->private_data
;
3263 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
3266 /* CHECKME: is this safe as one end closes ? */
3269 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
3270 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
3271 real_tty
= tty
->link
;
3274 * Break handling by driver
3276 if (!tty
->driver
->break_ctl
) {
3280 if (tty
->driver
->ioctl
)
3281 return tty
->driver
->ioctl(tty
, file
, cmd
, arg
);
3284 /* These two ioctl's always return success; even if */
3285 /* the driver doesn't support them. */
3288 if (!tty
->driver
->ioctl
)
3290 retval
= tty
->driver
->ioctl(tty
, file
, cmd
, arg
);
3291 if (retval
== -ENOIOCTLCMD
)
3298 * Factor out some common prep work
3306 retval
= tty_check_change(tty
);
3309 if (cmd
!= TIOCCBRK
) {
3310 tty_wait_until_sent(tty
, 0);
3311 if (signal_pending(current
))
3319 return tiocsti(tty
, p
);
3321 return tiocgwinsz(tty
, p
);
3323 return tiocswinsz(tty
, real_tty
, p
);
3325 return real_tty
!=tty
? -EINVAL
: tioccons(file
);
3327 return fionbio(file
, p
);
3329 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
3332 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
3335 if (current
->signal
->tty
!= tty
)
3340 return tiocsctty(tty
, arg
);
3342 return tiocgpgrp(tty
, real_tty
, p
);
3344 return tiocspgrp(tty
, real_tty
, p
);
3346 return tiocgsid(tty
, real_tty
, p
);
3348 /* FIXME: check this is ok */
3349 return put_user(tty
->ldisc
.num
, (int __user
*)p
);
3351 return tiocsetd(tty
, p
);
3354 return tioclinux(tty
, arg
);
3359 case TIOCSBRK
: /* Turn break on, unconditionally */
3360 tty
->driver
->break_ctl(tty
, -1);
3363 case TIOCCBRK
: /* Turn break off, unconditionally */
3364 tty
->driver
->break_ctl(tty
, 0);
3366 case TCSBRK
: /* SVID version: non-zero arg --> no break */
3367 /* non-zero arg means wait for all output data
3368 * to be sent (performed above) but don't send break.
3369 * This is used by the tcdrain() termios function.
3372 return send_break(tty
, 250);
3374 case TCSBRKP
: /* support for POSIX tcsendbreak() */
3375 return send_break(tty
, arg
? arg
*100 : 250);
3378 return tty_tiocmget(tty
, file
, p
);
3383 return tty_tiocmset(tty
, file
, cmd
, p
);
3388 /* flush tty buffer and allow ldisc to process ioctl */
3389 tty_buffer_flush(tty
);
3394 if (tty
->driver
->ioctl
) {
3395 retval
= (tty
->driver
->ioctl
)(tty
, file
, cmd
, arg
);
3396 if (retval
!= -ENOIOCTLCMD
)
3399 ld
= tty_ldisc_ref_wait(tty
);
3402 retval
= ld
->ioctl(tty
, file
, cmd
, arg
);
3403 if (retval
== -ENOIOCTLCMD
)
3406 tty_ldisc_deref(ld
);
3410 #ifdef CONFIG_COMPAT
3411 static long tty_compat_ioctl(struct file
* file
, unsigned int cmd
,
3414 struct inode
*inode
= file
->f_dentry
->d_inode
;
3415 struct tty_struct
*tty
= file
->private_data
;
3416 struct tty_ldisc
*ld
;
3417 int retval
= -ENOIOCTLCMD
;
3419 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
3422 if (tty
->driver
->compat_ioctl
) {
3423 retval
= (tty
->driver
->compat_ioctl
)(tty
, file
, cmd
, arg
);
3424 if (retval
!= -ENOIOCTLCMD
)
3428 ld
= tty_ldisc_ref_wait(tty
);
3429 if (ld
->compat_ioctl
)
3430 retval
= ld
->compat_ioctl(tty
, file
, cmd
, arg
);
3431 tty_ldisc_deref(ld
);
3438 * This implements the "Secure Attention Key" --- the idea is to
3439 * prevent trojan horses by killing all processes associated with this
3440 * tty when the user hits the "Secure Attention Key". Required for
3441 * super-paranoid applications --- see the Orange Book for more details.
3443 * This code could be nicer; ideally it should send a HUP, wait a few
3444 * seconds, then send a INT, and then a KILL signal. But you then
3445 * have to coordinate with the init process, since all processes associated
3446 * with the current tty must be dead before the new getty is allowed
3449 * Now, if it would be correct ;-/ The current code has a nasty hole -
3450 * it doesn't catch files in flight. We may send the descriptor to ourselves
3451 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3453 * Nasty bug: do_SAK is being called in interrupt context. This can
3454 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3456 void __do_SAK(struct tty_struct
*tty
)
3461 struct task_struct
*g
, *p
;
3462 struct pid
*session
;
3465 struct fdtable
*fdt
;
3469 session
= tty
->session
;
3471 tty_ldisc_flush(tty
);
3473 if (tty
->driver
->flush_buffer
)
3474 tty
->driver
->flush_buffer(tty
);
3476 read_lock(&tasklist_lock
);
3477 /* Kill the entire session */
3478 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
3479 printk(KERN_NOTICE
"SAK: killed process %d"
3480 " (%s): process_session(p)==tty->session\n",
3482 send_sig(SIGKILL
, p
, 1);
3483 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
3484 /* Now kill any processes that happen to have the
3487 do_each_thread(g
, p
) {
3488 if (p
->signal
->tty
== tty
) {
3489 printk(KERN_NOTICE
"SAK: killed process %d"
3490 " (%s): process_session(p)==tty->session\n",
3492 send_sig(SIGKILL
, p
, 1);
3498 * We don't take a ref to the file, so we must
3499 * hold ->file_lock instead.
3501 spin_lock(&p
->files
->file_lock
);
3502 fdt
= files_fdtable(p
->files
);
3503 for (i
=0; i
< fdt
->max_fds
; i
++) {
3504 filp
= fcheck_files(p
->files
, i
);
3507 if (filp
->f_op
->read
== tty_read
&&
3508 filp
->private_data
== tty
) {
3509 printk(KERN_NOTICE
"SAK: killed process %d"
3510 " (%s): fd#%d opened to the tty\n",
3511 p
->pid
, p
->comm
, i
);
3512 force_sig(SIGKILL
, p
);
3516 spin_unlock(&p
->files
->file_lock
);
3519 } while_each_thread(g
, p
);
3520 read_unlock(&tasklist_lock
);
3524 static void do_SAK_work(struct work_struct
*work
)
3526 struct tty_struct
*tty
=
3527 container_of(work
, struct tty_struct
, SAK_work
);
3532 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3533 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3534 * the values which we write to it will be identical to the values which it
3535 * already has. --akpm
3537 void do_SAK(struct tty_struct
*tty
)
3541 schedule_work(&tty
->SAK_work
);
3544 EXPORT_SYMBOL(do_SAK
);
3548 * @work: tty structure passed from work queue.
3550 * This routine is called out of the software interrupt to flush data
3551 * from the buffer chain to the line discipline.
3553 * Locking: holds tty->buf.lock to guard buffer list. Drops the lock
3554 * while invoking the line discipline receive_buf method. The
3555 * receive_buf method is single threaded for each tty instance.
3558 static void flush_to_ldisc(struct work_struct
*work
)
3560 struct tty_struct
*tty
=
3561 container_of(work
, struct tty_struct
, buf
.work
.work
);
3562 unsigned long flags
;
3563 struct tty_ldisc
*disc
;
3564 struct tty_buffer
*tbuf
, *head
;
3566 unsigned char *flag_buf
;
3568 disc
= tty_ldisc_ref(tty
);
3569 if (disc
== NULL
) /* !TTY_LDISC */
3572 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3573 head
= tty
->buf
.head
;
3575 tty
->buf
.head
= NULL
;
3577 int count
= head
->commit
- head
->read
;
3579 if (head
->next
== NULL
)
3583 tty_buffer_free(tty
, tbuf
);
3586 if (!tty
->receive_room
) {
3587 schedule_delayed_work(&tty
->buf
.work
, 1);
3590 if (count
> tty
->receive_room
)
3591 count
= tty
->receive_room
;
3592 char_buf
= head
->char_buf_ptr
+ head
->read
;
3593 flag_buf
= head
->flag_buf_ptr
+ head
->read
;
3594 head
->read
+= count
;
3595 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3596 disc
->receive_buf(tty
, char_buf
, flag_buf
, count
);
3597 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3599 tty
->buf
.head
= head
;
3601 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3603 tty_ldisc_deref(disc
);
3607 * tty_flip_buffer_push - terminal
3610 * Queue a push of the terminal flip buffers to the line discipline. This
3611 * function must not be called from IRQ context if tty->low_latency is set.
3613 * In the event of the queue being busy for flipping the work will be
3614 * held off and retried later.
3616 * Locking: tty buffer lock. Driver locks in low latency mode.
3619 void tty_flip_buffer_push(struct tty_struct
*tty
)
3621 unsigned long flags
;
3622 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3623 if (tty
->buf
.tail
!= NULL
)
3624 tty
->buf
.tail
->commit
= tty
->buf
.tail
->used
;
3625 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3627 if (tty
->low_latency
)
3628 flush_to_ldisc(&tty
->buf
.work
.work
);
3630 schedule_delayed_work(&tty
->buf
.work
, 1);
3633 EXPORT_SYMBOL(tty_flip_buffer_push
);
3637 * initialize_tty_struct
3638 * @tty: tty to initialize
3640 * This subroutine initializes a tty structure that has been newly
3643 * Locking: none - tty in question must not be exposed at this point
3646 static void initialize_tty_struct(struct tty_struct
*tty
)
3648 memset(tty
, 0, sizeof(struct tty_struct
));
3649 tty
->magic
= TTY_MAGIC
;
3650 tty_ldisc_assign(tty
, tty_ldisc_get(N_TTY
));
3651 tty
->session
= NULL
;
3653 tty
->overrun_time
= jiffies
;
3654 tty
->buf
.head
= tty
->buf
.tail
= NULL
;
3655 tty_buffer_init(tty
);
3656 INIT_DELAYED_WORK(&tty
->buf
.work
, flush_to_ldisc
);
3657 init_MUTEX(&tty
->buf
.pty_sem
);
3658 mutex_init(&tty
->termios_mutex
);
3659 init_waitqueue_head(&tty
->write_wait
);
3660 init_waitqueue_head(&tty
->read_wait
);
3661 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
3662 mutex_init(&tty
->atomic_read_lock
);
3663 mutex_init(&tty
->atomic_write_lock
);
3664 spin_lock_init(&tty
->read_lock
);
3665 INIT_LIST_HEAD(&tty
->tty_files
);
3666 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
3670 * The default put_char routine if the driver did not define one.
3673 static void tty_default_put_char(struct tty_struct
*tty
, unsigned char ch
)
3675 tty
->driver
->write(tty
, &ch
, 1);
3678 static struct class *tty_class
;
3681 * tty_register_device - register a tty device
3682 * @driver: the tty driver that describes the tty device
3683 * @index: the index in the tty driver for this tty device
3684 * @device: a struct device that is associated with this tty device.
3685 * This field is optional, if there is no known struct device
3686 * for this tty device it can be set to NULL safely.
3688 * Returns a pointer to the struct device for this tty device
3689 * (or ERR_PTR(-EFOO) on error).
3691 * This call is required to be made to register an individual tty device
3692 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3693 * that bit is not set, this function should not be called by a tty
3699 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
3700 struct device
*device
)
3703 dev_t dev
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
3705 if (index
>= driver
->num
) {
3706 printk(KERN_ERR
"Attempt to register invalid tty line number "
3708 return ERR_PTR(-EINVAL
);
3711 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
3712 pty_line_name(driver
, index
, name
);
3714 tty_line_name(driver
, index
, name
);
3716 return device_create(tty_class
, device
, dev
, name
);
3720 * tty_unregister_device - unregister a tty device
3721 * @driver: the tty driver that describes the tty device
3722 * @index: the index in the tty driver for this tty device
3724 * If a tty device is registered with a call to tty_register_device() then
3725 * this function must be called when the tty device is gone.
3730 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3732 device_destroy(tty_class
, MKDEV(driver
->major
, driver
->minor_start
) + index
);
3735 EXPORT_SYMBOL(tty_register_device
);
3736 EXPORT_SYMBOL(tty_unregister_device
);
3738 struct tty_driver
*alloc_tty_driver(int lines
)
3740 struct tty_driver
*driver
;
3742 driver
= kmalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3744 memset(driver
, 0, sizeof(struct tty_driver
));
3745 driver
->magic
= TTY_DRIVER_MAGIC
;
3746 driver
->num
= lines
;
3747 /* later we'll move allocation of tables here */
3752 void put_tty_driver(struct tty_driver
*driver
)
3757 void tty_set_operations(struct tty_driver
*driver
,
3758 const struct tty_operations
*op
)
3760 driver
->open
= op
->open
;
3761 driver
->close
= op
->close
;
3762 driver
->write
= op
->write
;
3763 driver
->put_char
= op
->put_char
;
3764 driver
->flush_chars
= op
->flush_chars
;
3765 driver
->write_room
= op
->write_room
;
3766 driver
->chars_in_buffer
= op
->chars_in_buffer
;
3767 driver
->ioctl
= op
->ioctl
;
3768 driver
->compat_ioctl
= op
->compat_ioctl
;
3769 driver
->set_termios
= op
->set_termios
;
3770 driver
->throttle
= op
->throttle
;
3771 driver
->unthrottle
= op
->unthrottle
;
3772 driver
->stop
= op
->stop
;
3773 driver
->start
= op
->start
;
3774 driver
->hangup
= op
->hangup
;
3775 driver
->break_ctl
= op
->break_ctl
;
3776 driver
->flush_buffer
= op
->flush_buffer
;
3777 driver
->set_ldisc
= op
->set_ldisc
;
3778 driver
->wait_until_sent
= op
->wait_until_sent
;
3779 driver
->send_xchar
= op
->send_xchar
;
3780 driver
->read_proc
= op
->read_proc
;
3781 driver
->write_proc
= op
->write_proc
;
3782 driver
->tiocmget
= op
->tiocmget
;
3783 driver
->tiocmset
= op
->tiocmset
;
3787 EXPORT_SYMBOL(alloc_tty_driver
);
3788 EXPORT_SYMBOL(put_tty_driver
);
3789 EXPORT_SYMBOL(tty_set_operations
);
3792 * Called by a tty driver to register itself.
3794 int tty_register_driver(struct tty_driver
*driver
)
3801 if (driver
->flags
& TTY_DRIVER_INSTALLED
)
3804 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && driver
->num
) {
3805 p
= kzalloc(driver
->num
* 3 * sizeof(void *), GFP_KERNEL
);
3810 if (!driver
->major
) {
3811 error
= alloc_chrdev_region(&dev
, driver
->minor_start
, driver
->num
,
3814 driver
->major
= MAJOR(dev
);
3815 driver
->minor_start
= MINOR(dev
);
3818 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3819 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3827 driver
->ttys
= (struct tty_struct
**)p
;
3828 driver
->termios
= (struct ktermios
**)(p
+ driver
->num
);
3829 driver
->termios_locked
= (struct ktermios
**)(p
+ driver
->num
* 2);
3831 driver
->ttys
= NULL
;
3832 driver
->termios
= NULL
;
3833 driver
->termios_locked
= NULL
;
3836 cdev_init(&driver
->cdev
, &tty_fops
);
3837 driver
->cdev
.owner
= driver
->owner
;
3838 error
= cdev_add(&driver
->cdev
, dev
, driver
->num
);
3840 unregister_chrdev_region(dev
, driver
->num
);
3841 driver
->ttys
= NULL
;
3842 driver
->termios
= driver
->termios_locked
= NULL
;
3847 if (!driver
->put_char
)
3848 driver
->put_char
= tty_default_put_char
;
3850 mutex_lock(&tty_mutex
);
3851 list_add(&driver
->tty_drivers
, &tty_drivers
);
3852 mutex_unlock(&tty_mutex
);
3854 if ( !(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
) ) {
3855 for(i
= 0; i
< driver
->num
; i
++)
3856 tty_register_device(driver
, i
, NULL
);
3858 proc_tty_register_driver(driver
);
3862 EXPORT_SYMBOL(tty_register_driver
);
3865 * Called by a tty driver to unregister itself.
3867 int tty_unregister_driver(struct tty_driver
*driver
)
3870 struct ktermios
*tp
;
3873 if (driver
->refcount
)
3876 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3878 mutex_lock(&tty_mutex
);
3879 list_del(&driver
->tty_drivers
);
3880 mutex_unlock(&tty_mutex
);
3883 * Free the termios and termios_locked structures because
3884 * we don't want to get memory leaks when modular tty
3885 * drivers are removed from the kernel.
3887 for (i
= 0; i
< driver
->num
; i
++) {
3888 tp
= driver
->termios
[i
];
3890 driver
->termios
[i
] = NULL
;
3893 tp
= driver
->termios_locked
[i
];
3895 driver
->termios_locked
[i
] = NULL
;
3898 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3899 tty_unregister_device(driver
, i
);
3902 proc_tty_unregister_driver(driver
);
3903 driver
->ttys
= NULL
;
3904 driver
->termios
= driver
->termios_locked
= NULL
;
3906 cdev_del(&driver
->cdev
);
3909 EXPORT_SYMBOL(tty_unregister_driver
);
3911 dev_t
tty_devnum(struct tty_struct
*tty
)
3913 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3915 EXPORT_SYMBOL(tty_devnum
);
3917 void proc_clear_tty(struct task_struct
*p
)
3919 spin_lock_irq(&p
->sighand
->siglock
);
3920 p
->signal
->tty
= NULL
;
3921 spin_unlock_irq(&p
->sighand
->siglock
);
3923 EXPORT_SYMBOL(proc_clear_tty
);
3925 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3928 /* We should not have a session or pgrp to here but.... */
3929 put_pid(tty
->session
);
3931 tty
->session
= get_pid(task_session(tsk
));
3932 tty
->pgrp
= get_pid(task_pgrp(tsk
));
3934 put_pid(tsk
->signal
->tty_old_pgrp
);
3935 tsk
->signal
->tty
= tty
;
3936 tsk
->signal
->tty_old_pgrp
= NULL
;
3939 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3941 spin_lock_irq(&tsk
->sighand
->siglock
);
3942 __proc_set_tty(tsk
, tty
);
3943 spin_unlock_irq(&tsk
->sighand
->siglock
);
3946 struct tty_struct
*get_current_tty(void)
3948 struct tty_struct
*tty
;
3949 WARN_ON_ONCE(!mutex_is_locked(&tty_mutex
));
3950 tty
= current
->signal
->tty
;
3952 * session->tty can be changed/cleared from under us, make sure we
3953 * issue the load. The obtained pointer, when not NULL, is valid as
3954 * long as we hold tty_mutex.
3959 EXPORT_SYMBOL_GPL(get_current_tty
);
3962 * Initialize the console device. This is called *early*, so
3963 * we can't necessarily depend on lots of kernel help here.
3964 * Just do some early initializations, and do the complex setup
3967 void __init
console_init(void)
3971 /* Setup the default TTY line discipline. */
3972 (void) tty_register_ldisc(N_TTY
, &tty_ldisc_N_TTY
);
3975 * set up the console device so that later boot sequences can
3976 * inform about problems etc..
3978 call
= __con_initcall_start
;
3979 while (call
< __con_initcall_end
) {
3986 extern int vty_init(void);
3989 static int __init
tty_class_init(void)
3991 tty_class
= class_create(THIS_MODULE
, "tty");
3992 if (IS_ERR(tty_class
))
3993 return PTR_ERR(tty_class
);
3997 postcore_initcall(tty_class_init
);
3999 /* 3/2004 jmc: why do these devices exist? */
4001 static struct cdev tty_cdev
, console_cdev
;
4002 #ifdef CONFIG_UNIX98_PTYS
4003 static struct cdev ptmx_cdev
;
4006 static struct cdev vc0_cdev
;
4010 * Ok, now we can initialize the rest of the tty devices and can count
4011 * on memory allocations, interrupts etc..
4013 static int __init
tty_init(void)
4015 cdev_init(&tty_cdev
, &tty_fops
);
4016 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
4017 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
4018 panic("Couldn't register /dev/tty driver\n");
4019 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), "tty");
4021 cdev_init(&console_cdev
, &console_fops
);
4022 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
4023 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
4024 panic("Couldn't register /dev/console driver\n");
4025 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), "console");
4027 #ifdef CONFIG_UNIX98_PTYS
4028 cdev_init(&ptmx_cdev
, &ptmx_fops
);
4029 if (cdev_add(&ptmx_cdev
, MKDEV(TTYAUX_MAJOR
, 2), 1) ||
4030 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 2), 1, "/dev/ptmx") < 0)
4031 panic("Couldn't register /dev/ptmx driver\n");
4032 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 2), "ptmx");
4036 cdev_init(&vc0_cdev
, &console_fops
);
4037 if (cdev_add(&vc0_cdev
, MKDEV(TTY_MAJOR
, 0), 1) ||
4038 register_chrdev_region(MKDEV(TTY_MAJOR
, 0), 1, "/dev/vc/0") < 0)
4039 panic("Couldn't register /dev/tty0 driver\n");
4040 device_create(tty_class
, NULL
, MKDEV(TTY_MAJOR
, 0), "tty0");
4046 module_init(tty_init
);