2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched.h>
73 #include <linux/interrupt.h>
74 #include <linux/tty.h>
75 #include <linux/tty_driver.h>
76 #include <linux/tty_flip.h>
77 #include <linux/devpts_fs.h>
78 #include <linux/file.h>
79 #include <linux/fdtable.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/device.h>
92 #include <linux/wait.h>
93 #include <linux/bitops.h>
94 #include <linux/delay.h>
95 #include <linux/seq_file.h>
96 #include <linux/serial.h>
97 #include <linux/ratelimit.h>
99 #include <linux/uaccess.h>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
106 #include <linux/nsproxy.h>
108 #undef TTY_DEBUG_HANGUP
109 #ifdef TTY_DEBUG_HANGUP
110 # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
112 # define tty_debug_hangup(tty, f, args...) do { } while (0)
115 #define TTY_PARANOIA_CHECK 1
116 #define CHECK_TTY_COUNT 1
118 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
119 .c_iflag = ICRNL | IXON,
120 .c_oflag = OPOST | ONLCR,
121 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
122 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
123 ECHOCTL | ECHOKE | IEXTEN,
127 /* .c_line = N_TTY, */
130 EXPORT_SYMBOL(tty_std_termios);
132 /* This list gets poked at by procfs and various bits of boot up code. This
133 could do with some rationalisation such as pulling the tty proc function
136 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
138 /* Mutex to protect creating and releasing a tty */
139 DEFINE_MUTEX(tty_mutex);
141 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
142 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
143 ssize_t redirected_tty_write(struct file *, const char __user *,
145 static unsigned int tty_poll(struct file *, poll_table *);
146 static int tty_open(struct inode *, struct file *);
147 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
149 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
152 #define tty_compat_ioctl NULL
154 static int __tty_fasync(int fd, struct file *filp, int on);
155 static int tty_fasync(int fd, struct file *filp, int on);
156 static void release_tty(struct tty_struct *tty, int idx);
159 * free_tty_struct - free a disused tty
160 * @tty: tty struct to free
162 * Free the write buffers, tty queue and tty memory itself.
164 * Locking: none. Must be called after tty is definitely unused
167 static void free_tty_struct(struct tty_struct *tty)
169 tty_ldisc_deinit(tty);
170 put_device(tty->dev);
171 kfree(tty->write_buf);
172 tty->magic = 0xDEADDEAD;
176 static inline struct tty_struct *file_tty(struct file *file)
178 return ((struct tty_file_private *)file->private_data)->tty;
181 int tty_alloc_file(struct file *file)
183 struct tty_file_private *priv;
185 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
189 file->private_data = priv;
194 /* Associate a new file with the tty structure */
195 void tty_add_file(struct tty_struct *tty, struct file *file)
197 struct tty_file_private *priv = file->private_data;
202 spin_lock(&tty->files_lock);
203 list_add(&priv->list, &tty->tty_files);
204 spin_unlock(&tty->files_lock);
208 * tty_free_file - free file->private_data
210 * This shall be used only for fail path handling when tty_add_file was not
213 void tty_free_file(struct file *file)
215 struct tty_file_private *priv = file->private_data;
217 file->private_data = NULL;
221 /* Delete file from its tty */
222 static void tty_del_file(struct file *file)
224 struct tty_file_private *priv = file->private_data;
225 struct tty_struct *tty = priv->tty;
227 spin_lock(&tty->files_lock);
228 list_del(&priv->list);
229 spin_unlock(&tty->files_lock);
234 * tty_name - return tty naming
235 * @tty: tty structure
237 * Convert a tty structure into a name. The name reflects the kernel
238 * naming policy and if udev is in use may not reflect user space
243 const char *tty_name(const struct tty_struct *tty)
245 if (!tty) /* Hmm. NULL pointer. That's fun. */
250 EXPORT_SYMBOL(tty_name);
252 const char *tty_driver_name(const struct tty_struct *tty)
254 if (!tty || !tty->driver)
256 return tty->driver->name;
259 static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
262 #ifdef TTY_PARANOIA_CHECK
264 pr_warn("(%d:%d): %s: NULL tty\n",
265 imajor(inode), iminor(inode), routine);
268 if (tty->magic != TTY_MAGIC) {
269 pr_warn("(%d:%d): %s: bad magic number\n",
270 imajor(inode), iminor(inode), routine);
277 /* Caller must hold tty_lock */
278 static int check_tty_count(struct tty_struct *tty, const char *routine)
280 #ifdef CHECK_TTY_COUNT
284 spin_lock(&tty->files_lock);
285 list_for_each(p, &tty->tty_files) {
288 spin_unlock(&tty->files_lock);
289 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
290 tty->driver->subtype == PTY_TYPE_SLAVE &&
291 tty->link && tty->link->count)
293 if (tty->count != count) {
294 tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
295 routine, tty->count, count);
303 * get_tty_driver - find device of a tty
304 * @dev_t: device identifier
305 * @index: returns the index of the tty
307 * This routine returns a tty driver structure, given a device number
308 * and also passes back the index number.
310 * Locking: caller must hold tty_mutex
313 static struct tty_driver *get_tty_driver(dev_t device, int *index)
315 struct tty_driver *p;
317 list_for_each_entry(p, &tty_drivers, tty_drivers) {
318 dev_t base = MKDEV(p->major, p->minor_start);
319 if (device < base || device >= base + p->num)
321 *index = device - base;
322 return tty_driver_kref_get(p);
327 #ifdef CONFIG_CONSOLE_POLL
330 * tty_find_polling_driver - find device of a polled tty
331 * @name: name string to match
332 * @line: pointer to resulting tty line nr
334 * This routine returns a tty driver structure, given a name
335 * and the condition that the tty driver is capable of polled
338 struct tty_driver *tty_find_polling_driver(char *name, int *line)
340 struct tty_driver *p, *res = NULL;
345 for (str = name; *str; str++)
346 if ((*str >= '0' && *str <= '9') || *str == ',')
352 tty_line = simple_strtoul(str, &str, 10);
354 mutex_lock(&tty_mutex);
355 /* Search through the tty devices to look for a match */
356 list_for_each_entry(p, &tty_drivers, tty_drivers) {
357 if (strncmp(name, p->name, len) != 0)
365 if (tty_line >= 0 && tty_line < p->num && p->ops &&
366 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
367 res = tty_driver_kref_get(p);
372 mutex_unlock(&tty_mutex);
376 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
379 static int is_ignored(int sig)
381 return (sigismember(¤t->blocked, sig) ||
382 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
386 * tty_check_change - check for POSIX terminal changes
389 * If we try to write to, or set the state of, a terminal and we're
390 * not in the foreground, send a SIGTTOU. If the signal is blocked or
391 * ignored, go ahead and perform the operation. (POSIX 7.2)
396 int __tty_check_change(struct tty_struct *tty, int sig)
399 struct pid *pgrp, *tty_pgrp;
402 if (current->signal->tty != tty)
406 pgrp = task_pgrp(current);
408 spin_lock_irqsave(&tty->ctrl_lock, flags);
409 tty_pgrp = tty->pgrp;
410 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
412 if (tty_pgrp && pgrp != tty->pgrp) {
413 if (is_ignored(sig)) {
416 } else if (is_current_pgrp_orphaned())
419 kill_pgrp(pgrp, sig, 1);
420 set_thread_flag(TIF_SIGPENDING);
427 tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);
432 int tty_check_change(struct tty_struct *tty)
434 return __tty_check_change(tty, SIGTTOU);
436 EXPORT_SYMBOL(tty_check_change);
438 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
439 size_t count, loff_t *ppos)
444 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
445 size_t count, loff_t *ppos)
450 /* No kernel lock held - none needed ;) */
451 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
453 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
456 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
459 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
462 static long hung_up_tty_compat_ioctl(struct file *file,
463 unsigned int cmd, unsigned long arg)
465 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
468 static int hung_up_tty_fasync(int fd, struct file *file, int on)
473 static const struct file_operations tty_fops = {
478 .unlocked_ioctl = tty_ioctl,
479 .compat_ioctl = tty_compat_ioctl,
481 .release = tty_release,
482 .fasync = tty_fasync,
485 static const struct file_operations console_fops = {
488 .write = redirected_tty_write,
490 .unlocked_ioctl = tty_ioctl,
491 .compat_ioctl = tty_compat_ioctl,
493 .release = tty_release,
494 .fasync = tty_fasync,
497 static const struct file_operations hung_up_tty_fops = {
499 .read = hung_up_tty_read,
500 .write = hung_up_tty_write,
501 .poll = hung_up_tty_poll,
502 .unlocked_ioctl = hung_up_tty_ioctl,
503 .compat_ioctl = hung_up_tty_compat_ioctl,
504 .release = tty_release,
505 .fasync = hung_up_tty_fasync,
508 static DEFINE_SPINLOCK(redirect_lock);
509 static struct file *redirect;
512 void proc_clear_tty(struct task_struct *p)
515 struct tty_struct *tty;
516 spin_lock_irqsave(&p->sighand->siglock, flags);
517 tty = p->signal->tty;
518 p->signal->tty = NULL;
519 spin_unlock_irqrestore(&p->sighand->siglock, flags);
524 * proc_set_tty - set the controlling terminal
526 * Only callable by the session leader and only if it does not already have
527 * a controlling terminal.
529 * Caller must hold: tty_lock()
530 * a readlock on tasklist_lock
533 static void __proc_set_tty(struct tty_struct *tty)
537 spin_lock_irqsave(&tty->ctrl_lock, flags);
539 * The session and fg pgrp references will be non-NULL if
540 * tiocsctty() is stealing the controlling tty
542 put_pid(tty->session);
544 tty->pgrp = get_pid(task_pgrp(current));
545 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
546 tty->session = get_pid(task_session(current));
547 if (current->signal->tty) {
548 tty_debug(tty, "current tty %s not NULL!!\n",
549 current->signal->tty->name);
550 tty_kref_put(current->signal->tty);
552 put_pid(current->signal->tty_old_pgrp);
553 current->signal->tty = tty_kref_get(tty);
554 current->signal->tty_old_pgrp = NULL;
557 static void proc_set_tty(struct tty_struct *tty)
559 spin_lock_irq(¤t->sighand->siglock);
561 spin_unlock_irq(¤t->sighand->siglock);
564 struct tty_struct *get_current_tty(void)
566 struct tty_struct *tty;
569 spin_lock_irqsave(¤t->sighand->siglock, flags);
570 tty = tty_kref_get(current->signal->tty);
571 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
574 EXPORT_SYMBOL_GPL(get_current_tty);
576 static void session_clear_tty(struct pid *session)
578 struct task_struct *p;
579 do_each_pid_task(session, PIDTYPE_SID, p) {
581 } while_each_pid_task(session, PIDTYPE_SID, p);
585 * tty_wakeup - request more data
588 * Internal and external helper for wakeups of tty. This function
589 * informs the line discipline if present that the driver is ready
590 * to receive more output data.
593 void tty_wakeup(struct tty_struct *tty)
595 struct tty_ldisc *ld;
597 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
598 ld = tty_ldisc_ref(tty);
600 if (ld->ops->write_wakeup)
601 ld->ops->write_wakeup(tty);
605 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
608 EXPORT_SYMBOL_GPL(tty_wakeup);
611 * tty_signal_session_leader - sends SIGHUP to session leader
612 * @tty controlling tty
613 * @exit_session if non-zero, signal all foreground group processes
615 * Send SIGHUP and SIGCONT to the session leader and its process group.
616 * Optionally, signal all processes in the foreground process group.
618 * Returns the number of processes in the session with this tty
619 * as their controlling terminal. This value is used to drop
620 * tty references for those processes.
622 static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
624 struct task_struct *p;
626 struct pid *tty_pgrp = NULL;
628 read_lock(&tasklist_lock);
630 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
631 spin_lock_irq(&p->sighand->siglock);
632 if (p->signal->tty == tty) {
633 p->signal->tty = NULL;
634 /* We defer the dereferences outside fo
638 if (!p->signal->leader) {
639 spin_unlock_irq(&p->sighand->siglock);
642 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
643 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
644 put_pid(p->signal->tty_old_pgrp); /* A noop */
645 spin_lock(&tty->ctrl_lock);
646 tty_pgrp = get_pid(tty->pgrp);
648 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
649 spin_unlock(&tty->ctrl_lock);
650 spin_unlock_irq(&p->sighand->siglock);
651 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
653 read_unlock(&tasklist_lock);
657 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
665 * __tty_hangup - actual handler for hangup events
668 * This can be called by a "kworker" kernel thread. That is process
669 * synchronous but doesn't hold any locks, so we need to make sure we
670 * have the appropriate locks for what we're doing.
672 * The hangup event clears any pending redirections onto the hung up
673 * device. It ensures future writes will error and it does the needed
674 * line discipline hangup and signal delivery. The tty object itself
679 * redirect lock for undoing redirection
680 * file list lock for manipulating list of ttys
681 * tty_ldiscs_lock from called functions
682 * termios_rwsem resetting termios data
683 * tasklist_lock to walk task list for hangup event
684 * ->siglock to protect ->signal/->sighand
686 static void __tty_hangup(struct tty_struct *tty, int exit_session)
688 struct file *cons_filp = NULL;
689 struct file *filp, *f = NULL;
690 struct tty_file_private *priv;
691 int closecount = 0, n;
698 spin_lock(&redirect_lock);
699 if (redirect && file_tty(redirect) == tty) {
703 spin_unlock(&redirect_lock);
707 if (test_bit(TTY_HUPPED, &tty->flags)) {
712 /* inuse_filps is protected by the single tty lock,
713 this really needs to change if we want to flush the
714 workqueue with the lock held */
715 check_tty_count(tty, "tty_hangup");
717 spin_lock(&tty->files_lock);
718 /* This breaks for file handles being sent over AF_UNIX sockets ? */
719 list_for_each_entry(priv, &tty->tty_files, list) {
721 if (filp->f_op->write == redirected_tty_write)
723 if (filp->f_op->write != tty_write)
726 __tty_fasync(-1, filp, 0); /* can't block */
727 filp->f_op = &hung_up_tty_fops;
729 spin_unlock(&tty->files_lock);
731 refs = tty_signal_session_leader(tty, exit_session);
732 /* Account for the p->signal references we killed */
736 tty_ldisc_hangup(tty, cons_filp != NULL);
738 spin_lock_irq(&tty->ctrl_lock);
739 clear_bit(TTY_THROTTLED, &tty->flags);
740 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
741 put_pid(tty->session);
745 tty->ctrl_status = 0;
746 spin_unlock_irq(&tty->ctrl_lock);
749 * If one of the devices matches a console pointer, we
750 * cannot just call hangup() because that will cause
751 * tty->count and state->count to go out of sync.
752 * So we just call close() the right number of times.
756 for (n = 0; n < closecount; n++)
757 tty->ops->close(tty, cons_filp);
758 } else if (tty->ops->hangup)
759 tty->ops->hangup(tty);
761 * We don't want to have driver/ldisc interactions beyond the ones
762 * we did here. The driver layer expects no calls after ->hangup()
763 * from the ldisc side, which is now guaranteed.
765 set_bit(TTY_HUPPED, &tty->flags);
772 static void do_tty_hangup(struct work_struct *work)
774 struct tty_struct *tty =
775 container_of(work, struct tty_struct, hangup_work);
777 __tty_hangup(tty, 0);
781 * tty_hangup - trigger a hangup event
782 * @tty: tty to hangup
784 * A carrier loss (virtual or otherwise) has occurred on this like
785 * schedule a hangup sequence to run after this event.
788 void tty_hangup(struct tty_struct *tty)
790 tty_debug_hangup(tty, "hangup\n");
791 schedule_work(&tty->hangup_work);
794 EXPORT_SYMBOL(tty_hangup);
797 * tty_vhangup - process vhangup
798 * @tty: tty to hangup
800 * The user has asked via system call for the terminal to be hung up.
801 * We do this synchronously so that when the syscall returns the process
802 * is complete. That guarantee is necessary for security reasons.
805 void tty_vhangup(struct tty_struct *tty)
807 tty_debug_hangup(tty, "vhangup\n");
808 __tty_hangup(tty, 0);
811 EXPORT_SYMBOL(tty_vhangup);
815 * tty_vhangup_self - process vhangup for own ctty
817 * Perform a vhangup on the current controlling tty
820 void tty_vhangup_self(void)
822 struct tty_struct *tty;
824 tty = get_current_tty();
832 * tty_vhangup_session - hangup session leader exit
833 * @tty: tty to hangup
835 * The session leader is exiting and hanging up its controlling terminal.
836 * Every process in the foreground process group is signalled SIGHUP.
838 * We do this synchronously so that when the syscall returns the process
839 * is complete. That guarantee is necessary for security reasons.
842 static void tty_vhangup_session(struct tty_struct *tty)
844 tty_debug_hangup(tty, "session hangup\n");
845 __tty_hangup(tty, 1);
849 * tty_hung_up_p - was tty hung up
850 * @filp: file pointer of tty
852 * Return true if the tty has been subject to a vhangup or a carrier
856 int tty_hung_up_p(struct file *filp)
858 return (filp->f_op == &hung_up_tty_fops);
861 EXPORT_SYMBOL(tty_hung_up_p);
864 * disassociate_ctty - disconnect controlling tty
865 * @on_exit: true if exiting so need to "hang up" the session
867 * This function is typically called only by the session leader, when
868 * it wants to disassociate itself from its controlling tty.
870 * It performs the following functions:
871 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
872 * (2) Clears the tty from being controlling the session
873 * (3) Clears the controlling tty for all processes in the
876 * The argument on_exit is set to 1 if called when a process is
877 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
880 * BTM is taken for hysterical raisins, and held when
881 * called from no_tty().
882 * tty_mutex is taken to protect tty
883 * ->siglock is taken to protect ->signal/->sighand
884 * tasklist_lock is taken to walk process list for sessions
885 * ->siglock is taken to protect ->signal/->sighand
888 void disassociate_ctty(int on_exit)
890 struct tty_struct *tty;
892 if (!current->signal->leader)
895 tty = get_current_tty();
897 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
898 tty_vhangup_session(tty);
900 struct pid *tty_pgrp = tty_get_pgrp(tty);
902 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
904 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
910 } else if (on_exit) {
911 struct pid *old_pgrp;
912 spin_lock_irq(¤t->sighand->siglock);
913 old_pgrp = current->signal->tty_old_pgrp;
914 current->signal->tty_old_pgrp = NULL;
915 spin_unlock_irq(¤t->sighand->siglock);
917 kill_pgrp(old_pgrp, SIGHUP, on_exit);
918 kill_pgrp(old_pgrp, SIGCONT, on_exit);
924 spin_lock_irq(¤t->sighand->siglock);
925 put_pid(current->signal->tty_old_pgrp);
926 current->signal->tty_old_pgrp = NULL;
928 tty = tty_kref_get(current->signal->tty);
931 spin_lock_irqsave(&tty->ctrl_lock, flags);
932 put_pid(tty->session);
936 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
939 tty_debug_hangup(tty, "no current tty\n");
941 spin_unlock_irq(¤t->sighand->siglock);
942 /* Now clear signal->tty under the lock */
943 read_lock(&tasklist_lock);
944 session_clear_tty(task_session(current));
945 read_unlock(&tasklist_lock);
950 * no_tty - Ensure the current process does not have a controlling tty
954 /* FIXME: Review locking here. The tty_lock never covered any race
955 between a new association and proc_clear_tty but possible we need
956 to protect against this anyway */
957 struct task_struct *tsk = current;
958 disassociate_ctty(0);
964 * stop_tty - propagate flow control
967 * Perform flow control to the driver. May be called
968 * on an already stopped device and will not re-call the driver
971 * This functionality is used by both the line disciplines for
972 * halting incoming flow and by the driver. It may therefore be
973 * called from any context, may be under the tty atomic_write_lock
980 void __stop_tty(struct tty_struct *tty)
989 void stop_tty(struct tty_struct *tty)
993 spin_lock_irqsave(&tty->flow_lock, flags);
995 spin_unlock_irqrestore(&tty->flow_lock, flags);
997 EXPORT_SYMBOL(stop_tty);
1000 * start_tty - propagate flow control
1001 * @tty: tty to start
1003 * Start a tty that has been stopped if at all possible. If this
1004 * tty was previous stopped and is now being started, the driver
1005 * start method is invoked and the line discipline woken.
1011 void __start_tty(struct tty_struct *tty)
1013 if (!tty->stopped || tty->flow_stopped)
1016 if (tty->ops->start)
1017 tty->ops->start(tty);
1021 void start_tty(struct tty_struct *tty)
1023 unsigned long flags;
1025 spin_lock_irqsave(&tty->flow_lock, flags);
1027 spin_unlock_irqrestore(&tty->flow_lock, flags);
1029 EXPORT_SYMBOL(start_tty);
1031 static void tty_update_time(struct timespec *time)
1033 unsigned long sec = get_seconds();
1036 * We only care if the two values differ in anything other than the
1037 * lower three bits (i.e every 8 seconds). If so, then we can update
1038 * the time of the tty device, otherwise it could be construded as a
1039 * security leak to let userspace know the exact timing of the tty.
1041 if ((sec ^ time->tv_sec) & ~7)
1046 * tty_read - read method for tty device files
1047 * @file: pointer to tty file
1049 * @count: size of user buffer
1052 * Perform the read system call function on this terminal device. Checks
1053 * for hung up devices before calling the line discipline method.
1056 * Locks the line discipline internally while needed. Multiple
1057 * read calls may be outstanding in parallel.
1060 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1064 struct inode *inode = file_inode(file);
1065 struct tty_struct *tty = file_tty(file);
1066 struct tty_ldisc *ld;
1068 if (tty_paranoia_check(tty, inode, "tty_read"))
1070 if (!tty || tty_io_error(tty))
1073 /* We want to wait for the line discipline to sort out in this
1075 ld = tty_ldisc_ref_wait(tty);
1077 return hung_up_tty_read(file, buf, count, ppos);
1079 i = ld->ops->read(tty, file, buf, count);
1082 tty_ldisc_deref(ld);
1085 tty_update_time(&inode->i_atime);
1090 static void tty_write_unlock(struct tty_struct *tty)
1092 mutex_unlock(&tty->atomic_write_lock);
1093 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1096 static int tty_write_lock(struct tty_struct *tty, int ndelay)
1098 if (!mutex_trylock(&tty->atomic_write_lock)) {
1101 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1102 return -ERESTARTSYS;
1108 * Split writes up in sane blocksizes to avoid
1109 * denial-of-service type attacks
1111 static inline ssize_t do_tty_write(
1112 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1113 struct tty_struct *tty,
1115 const char __user *buf,
1118 ssize_t ret, written = 0;
1121 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1126 * We chunk up writes into a temporary buffer. This
1127 * simplifies low-level drivers immensely, since they
1128 * don't have locking issues and user mode accesses.
1130 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1133 * The default chunk-size is 2kB, because the NTTY
1134 * layer has problems with bigger chunks. It will
1135 * claim to be able to handle more characters than
1138 * FIXME: This can probably go away now except that 64K chunks
1139 * are too likely to fail unless switched to vmalloc...
1142 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1147 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1148 if (tty->write_cnt < chunk) {
1149 unsigned char *buf_chunk;
1154 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1159 kfree(tty->write_buf);
1160 tty->write_cnt = chunk;
1161 tty->write_buf = buf_chunk;
1164 /* Do the write .. */
1166 size_t size = count;
1170 if (copy_from_user(tty->write_buf, buf, size))
1172 ret = write(tty, file, tty->write_buf, size);
1181 if (signal_pending(current))
1186 tty_update_time(&file_inode(file)->i_mtime);
1190 tty_write_unlock(tty);
1195 * tty_write_message - write a message to a certain tty, not just the console.
1196 * @tty: the destination tty_struct
1197 * @msg: the message to write
1199 * This is used for messages that need to be redirected to a specific tty.
1200 * We don't put it into the syslog queue right now maybe in the future if
1203 * We must still hold the BTM and test the CLOSING flag for the moment.
1206 void tty_write_message(struct tty_struct *tty, char *msg)
1209 mutex_lock(&tty->atomic_write_lock);
1211 if (tty->ops->write && tty->count > 0)
1212 tty->ops->write(tty, msg, strlen(msg));
1214 tty_write_unlock(tty);
1221 * tty_write - write method for tty device file
1222 * @file: tty file pointer
1223 * @buf: user data to write
1224 * @count: bytes to write
1227 * Write data to a tty device via the line discipline.
1230 * Locks the line discipline as required
1231 * Writes to the tty driver are serialized by the atomic_write_lock
1232 * and are then processed in chunks to the device. The line discipline
1233 * write method will not be invoked in parallel for each device.
1236 static ssize_t tty_write(struct file *file, const char __user *buf,
1237 size_t count, loff_t *ppos)
1239 struct tty_struct *tty = file_tty(file);
1240 struct tty_ldisc *ld;
1243 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1245 if (!tty || !tty->ops->write || tty_io_error(tty))
1247 /* Short term debug to catch buggy drivers */
1248 if (tty->ops->write_room == NULL)
1249 tty_err(tty, "missing write_room method\n");
1250 ld = tty_ldisc_ref_wait(tty);
1252 return hung_up_tty_write(file, buf, count, ppos);
1253 if (!ld->ops->write)
1256 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1257 tty_ldisc_deref(ld);
1261 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1262 size_t count, loff_t *ppos)
1264 struct file *p = NULL;
1266 spin_lock(&redirect_lock);
1268 p = get_file(redirect);
1269 spin_unlock(&redirect_lock);
1273 res = vfs_write(p, buf, count, &p->f_pos);
1277 return tty_write(file, buf, count, ppos);
1281 * tty_send_xchar - send priority character
1283 * Send a high priority character to the tty even if stopped
1285 * Locking: none for xchar method, write ordering for write method.
1288 int tty_send_xchar(struct tty_struct *tty, char ch)
1290 int was_stopped = tty->stopped;
1292 if (tty->ops->send_xchar) {
1293 down_read(&tty->termios_rwsem);
1294 tty->ops->send_xchar(tty, ch);
1295 up_read(&tty->termios_rwsem);
1299 if (tty_write_lock(tty, 0) < 0)
1300 return -ERESTARTSYS;
1302 down_read(&tty->termios_rwsem);
1305 tty->ops->write(tty, &ch, 1);
1308 up_read(&tty->termios_rwsem);
1309 tty_write_unlock(tty);
1313 static char ptychar[] = "pqrstuvwxyzabcde";
1316 * pty_line_name - generate name for a pty
1317 * @driver: the tty driver in use
1318 * @index: the minor number
1319 * @p: output buffer of at least 6 bytes
1321 * Generate a name from a driver reference and write it to the output
1326 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1328 int i = index + driver->name_base;
1329 /* ->name is initialized to "ttyp", but "tty" is expected */
1330 sprintf(p, "%s%c%x",
1331 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1332 ptychar[i >> 4 & 0xf], i & 0xf);
1336 * tty_line_name - generate name for a tty
1337 * @driver: the tty driver in use
1338 * @index: the minor number
1339 * @p: output buffer of at least 7 bytes
1341 * Generate a name from a driver reference and write it to the output
1346 static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1348 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1349 return sprintf(p, "%s", driver->name);
1351 return sprintf(p, "%s%d", driver->name,
1352 index + driver->name_base);
1356 * tty_driver_lookup_tty() - find an existing tty, if any
1357 * @driver: the driver for the tty
1358 * @idx: the minor number
1360 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1361 * driver lookup() method returns an error.
1363 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1365 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1366 struct file *file, int idx)
1368 struct tty_struct *tty;
1370 if (driver->ops->lookup)
1371 tty = driver->ops->lookup(driver, file, idx);
1373 tty = driver->ttys[idx];
1381 * tty_init_termios - helper for termios setup
1382 * @tty: the tty to set up
1384 * Initialise the termios structures for this tty. Thus runs under
1385 * the tty_mutex currently so we can be relaxed about ordering.
1388 void tty_init_termios(struct tty_struct *tty)
1390 struct ktermios *tp;
1391 int idx = tty->index;
1393 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1394 tty->termios = tty->driver->init_termios;
1396 /* Check for lazy saved data */
1397 tp = tty->driver->termios[idx];
1400 tty->termios.c_line = tty->driver->init_termios.c_line;
1402 tty->termios = tty->driver->init_termios;
1404 /* Compatibility until drivers always set this */
1405 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1406 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1408 EXPORT_SYMBOL_GPL(tty_init_termios);
1410 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1412 tty_init_termios(tty);
1413 tty_driver_kref_get(driver);
1415 driver->ttys[tty->index] = tty;
1418 EXPORT_SYMBOL_GPL(tty_standard_install);
1421 * tty_driver_install_tty() - install a tty entry in the driver
1422 * @driver: the driver for the tty
1425 * Install a tty object into the driver tables. The tty->index field
1426 * will be set by the time this is called. This method is responsible
1427 * for ensuring any need additional structures are allocated and
1430 * Locking: tty_mutex for now
1432 static int tty_driver_install_tty(struct tty_driver *driver,
1433 struct tty_struct *tty)
1435 return driver->ops->install ? driver->ops->install(driver, tty) :
1436 tty_standard_install(driver, tty);
1440 * tty_driver_remove_tty() - remove a tty from the driver tables
1441 * @driver: the driver for the tty
1442 * @idx: the minor number
1444 * Remvoe a tty object from the driver tables. The tty->index field
1445 * will be set by the time this is called.
1447 * Locking: tty_mutex for now
1449 static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1451 if (driver->ops->remove)
1452 driver->ops->remove(driver, tty);
1454 driver->ttys[tty->index] = NULL;
1458 * tty_reopen() - fast re-open of an open tty
1459 * @tty - the tty to open
1461 * Return 0 on success, -errno on error.
1462 * Re-opens on master ptys are not allowed and return -EIO.
1464 * Locking: Caller must hold tty_lock
1466 static int tty_reopen(struct tty_struct *tty)
1468 struct tty_driver *driver = tty->driver;
1470 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1471 driver->subtype == PTY_TYPE_MASTER)
1477 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1483 return tty_ldisc_reinit(tty, tty->termios.c_line);
1489 * tty_init_dev - initialise a tty device
1490 * @driver: tty driver we are opening a device on
1491 * @idx: device index
1492 * @ret_tty: returned tty structure
1494 * Prepare a tty device. This may not be a "new" clean device but
1495 * could also be an active device. The pty drivers require special
1496 * handling because of this.
1499 * The function is called under the tty_mutex, which
1500 * protects us from the tty struct or driver itself going away.
1502 * On exit the tty device has the line discipline attached and
1503 * a reference count of 1. If a pair was created for pty/tty use
1504 * and the other was a pty master then it too has a reference count of 1.
1506 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1507 * failed open. The new code protects the open with a mutex, so it's
1508 * really quite straightforward. The mutex locking can probably be
1509 * relaxed for the (most common) case of reopening a tty.
1512 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1514 struct tty_struct *tty;
1518 * First time open is complex, especially for PTY devices.
1519 * This code guarantees that either everything succeeds and the
1520 * TTY is ready for operation, or else the table slots are vacated
1521 * and the allocated memory released. (Except that the termios
1522 * and locked termios may be retained.)
1525 if (!try_module_get(driver->owner))
1526 return ERR_PTR(-ENODEV);
1528 tty = alloc_tty_struct(driver, idx);
1531 goto err_module_put;
1535 retval = tty_driver_install_tty(driver, tty);
1540 tty->port = driver->ports[idx];
1542 WARN_RATELIMIT(!tty->port,
1543 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1544 __func__, tty->driver->name);
1546 tty->port->itty = tty;
1549 * Structures all installed ... call the ldisc open routines.
1550 * If we fail here just call release_tty to clean up. No need
1551 * to decrement the use counts, as release_tty doesn't care.
1553 retval = tty_ldisc_setup(tty, tty->link);
1555 goto err_release_tty;
1556 /* Return the tty locked so that it cannot vanish under the caller */
1561 free_tty_struct(tty);
1563 module_put(driver->owner);
1564 return ERR_PTR(retval);
1566 /* call the tty release_tty routine to clean out this slot */
1569 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1571 release_tty(tty, idx);
1572 return ERR_PTR(retval);
1575 static void tty_free_termios(struct tty_struct *tty)
1577 struct ktermios *tp;
1578 int idx = tty->index;
1580 /* If the port is going to reset then it has no termios to save */
1581 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1584 /* Stash the termios data */
1585 tp = tty->driver->termios[idx];
1587 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1590 tty->driver->termios[idx] = tp;
1596 * tty_flush_works - flush all works of a tty/pty pair
1597 * @tty: tty device to flush works for (or either end of a pty pair)
1599 * Sync flush all works belonging to @tty (and the 'other' tty).
1601 static void tty_flush_works(struct tty_struct *tty)
1603 flush_work(&tty->SAK_work);
1604 flush_work(&tty->hangup_work);
1606 flush_work(&tty->link->SAK_work);
1607 flush_work(&tty->link->hangup_work);
1612 * release_one_tty - release tty structure memory
1613 * @kref: kref of tty we are obliterating
1615 * Releases memory associated with a tty structure, and clears out the
1616 * driver table slots. This function is called when a device is no longer
1617 * in use. It also gets called when setup of a device fails.
1620 * takes the file list lock internally when working on the list
1621 * of ttys that the driver keeps.
1623 * This method gets called from a work queue so that the driver private
1624 * cleanup ops can sleep (needed for USB at least)
1626 static void release_one_tty(struct work_struct *work)
1628 struct tty_struct *tty =
1629 container_of(work, struct tty_struct, hangup_work);
1630 struct tty_driver *driver = tty->driver;
1631 struct module *owner = driver->owner;
1633 if (tty->ops->cleanup)
1634 tty->ops->cleanup(tty);
1637 tty_driver_kref_put(driver);
1640 spin_lock(&tty->files_lock);
1641 list_del_init(&tty->tty_files);
1642 spin_unlock(&tty->files_lock);
1645 put_pid(tty->session);
1646 free_tty_struct(tty);
1649 static void queue_release_one_tty(struct kref *kref)
1651 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1653 /* The hangup queue is now free so we can reuse it rather than
1654 waste a chunk of memory for each port */
1655 INIT_WORK(&tty->hangup_work, release_one_tty);
1656 schedule_work(&tty->hangup_work);
1660 * tty_kref_put - release a tty kref
1663 * Release a reference to a tty device and if need be let the kref
1664 * layer destruct the object for us
1667 void tty_kref_put(struct tty_struct *tty)
1670 kref_put(&tty->kref, queue_release_one_tty);
1672 EXPORT_SYMBOL(tty_kref_put);
1675 * release_tty - release tty structure memory
1677 * Release both @tty and a possible linked partner (think pty pair),
1678 * and decrement the refcount of the backing module.
1682 * takes the file list lock internally when working on the list
1683 * of ttys that the driver keeps.
1686 static void release_tty(struct tty_struct *tty, int idx)
1688 /* This should always be true but check for the moment */
1689 WARN_ON(tty->index != idx);
1690 WARN_ON(!mutex_is_locked(&tty_mutex));
1691 if (tty->ops->shutdown)
1692 tty->ops->shutdown(tty);
1693 tty_free_termios(tty);
1694 tty_driver_remove_tty(tty->driver, tty);
1695 tty->port->itty = NULL;
1697 tty->link->port->itty = NULL;
1698 tty_buffer_cancel_work(tty->port);
1700 tty_kref_put(tty->link);
1705 * tty_release_checks - check a tty before real release
1706 * @tty: tty to check
1707 * @o_tty: link of @tty (if any)
1708 * @idx: index of the tty
1710 * Performs some paranoid checking before true release of the @tty.
1711 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1713 static int tty_release_checks(struct tty_struct *tty, int idx)
1715 #ifdef TTY_PARANOIA_CHECK
1716 if (idx < 0 || idx >= tty->driver->num) {
1717 tty_debug(tty, "bad idx %d\n", idx);
1721 /* not much to check for devpts */
1722 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1725 if (tty != tty->driver->ttys[idx]) {
1726 tty_debug(tty, "bad driver table[%d] = %p\n",
1727 idx, tty->driver->ttys[idx]);
1730 if (tty->driver->other) {
1731 struct tty_struct *o_tty = tty->link;
1733 if (o_tty != tty->driver->other->ttys[idx]) {
1734 tty_debug(tty, "bad other table[%d] = %p\n",
1735 idx, tty->driver->other->ttys[idx]);
1738 if (o_tty->link != tty) {
1739 tty_debug(tty, "bad link = %p\n", o_tty->link);
1748 * tty_release - vfs callback for close
1749 * @inode: inode of tty
1750 * @filp: file pointer for handle to tty
1752 * Called the last time each file handle is closed that references
1753 * this tty. There may however be several such references.
1756 * Takes bkl. See tty_release_dev
1758 * Even releasing the tty structures is a tricky business.. We have
1759 * to be very careful that the structures are all released at the
1760 * same time, as interrupts might otherwise get the wrong pointers.
1762 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1763 * lead to double frees or releasing memory still in use.
1766 int tty_release(struct inode *inode, struct file *filp)
1768 struct tty_struct *tty = file_tty(filp);
1769 struct tty_struct *o_tty = NULL;
1770 int do_sleep, final;
1775 if (tty_paranoia_check(tty, inode, __func__))
1779 check_tty_count(tty, __func__);
1781 __tty_fasync(-1, filp, 0);
1784 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1785 tty->driver->subtype == PTY_TYPE_MASTER)
1788 if (tty_release_checks(tty, idx)) {
1793 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1795 if (tty->ops->close)
1796 tty->ops->close(tty, filp);
1798 /* If tty is pty master, lock the slave pty (stable lock order) */
1799 tty_lock_slave(o_tty);
1802 * Sanity check: if tty->count is going to zero, there shouldn't be
1803 * any waiters on tty->read_wait or tty->write_wait. We test the
1804 * wait queues and kick everyone out _before_ actually starting to
1805 * close. This ensures that we won't block while releasing the tty
1808 * The test for the o_tty closing is necessary, since the master and
1809 * slave sides may close in any order. If the slave side closes out
1810 * first, its count will be one, since the master side holds an open.
1811 * Thus this test wouldn't be triggered at the time the slave closed,
1817 if (tty->count <= 1) {
1818 if (waitqueue_active(&tty->read_wait)) {
1819 wake_up_poll(&tty->read_wait, POLLIN);
1822 if (waitqueue_active(&tty->write_wait)) {
1823 wake_up_poll(&tty->write_wait, POLLOUT);
1827 if (o_tty && o_tty->count <= 1) {
1828 if (waitqueue_active(&o_tty->read_wait)) {
1829 wake_up_poll(&o_tty->read_wait, POLLIN);
1832 if (waitqueue_active(&o_tty->write_wait)) {
1833 wake_up_poll(&o_tty->write_wait, POLLOUT);
1842 tty_warn(tty, "read/write wait queue active!\n");
1844 schedule_timeout_killable(timeout);
1845 if (timeout < 120 * HZ)
1846 timeout = 2 * timeout + 1;
1848 timeout = MAX_SCHEDULE_TIMEOUT;
1852 if (--o_tty->count < 0) {
1853 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1857 if (--tty->count < 0) {
1858 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1863 * We've decremented tty->count, so we need to remove this file
1864 * descriptor off the tty->tty_files list; this serves two
1866 * - check_tty_count sees the correct number of file descriptors
1867 * associated with this tty.
1868 * - do_tty_hangup no longer sees this file descriptor as
1869 * something that needs to be handled for hangups.
1874 * Perform some housekeeping before deciding whether to return.
1876 * If _either_ side is closing, make sure there aren't any
1877 * processes that still think tty or o_tty is their controlling
1881 read_lock(&tasklist_lock);
1882 session_clear_tty(tty->session);
1884 session_clear_tty(o_tty->session);
1885 read_unlock(&tasklist_lock);
1888 /* check whether both sides are closing ... */
1889 final = !tty->count && !(o_tty && o_tty->count);
1891 tty_unlock_slave(o_tty);
1894 /* At this point, the tty->count == 0 should ensure a dead tty
1895 cannot be re-opened by a racing opener */
1900 tty_debug_hangup(tty, "final close\n");
1902 * Ask the line discipline code to release its structures
1904 tty_ldisc_release(tty);
1906 /* Wait for pending work before tty destruction commmences */
1907 tty_flush_works(tty);
1909 tty_debug_hangup(tty, "freeing structure\n");
1911 * The release_tty function takes care of the details of clearing
1912 * the slots and preserving the termios structure. The tty_unlock_pair
1913 * should be safe as we keep a kref while the tty is locked (so the
1914 * unlock never unlocks a freed tty).
1916 mutex_lock(&tty_mutex);
1917 release_tty(tty, idx);
1918 mutex_unlock(&tty_mutex);
1924 * tty_open_current_tty - get locked tty of current task
1925 * @device: device number
1926 * @filp: file pointer to tty
1927 * @return: locked tty of the current task iff @device is /dev/tty
1929 * Performs a re-open of the current task's controlling tty.
1931 * We cannot return driver and index like for the other nodes because
1932 * devpts will not work then. It expects inodes to be from devpts FS.
1934 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1936 struct tty_struct *tty;
1939 if (device != MKDEV(TTYAUX_MAJOR, 0))
1942 tty = get_current_tty();
1944 return ERR_PTR(-ENXIO);
1946 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1949 tty_kref_put(tty); /* safe to drop the kref now */
1951 retval = tty_reopen(tty);
1954 tty = ERR_PTR(retval);
1960 * tty_lookup_driver - lookup a tty driver for a given device file
1961 * @device: device number
1962 * @filp: file pointer to tty
1963 * @index: index for the device in the @return driver
1964 * @return: driver for this inode (with increased refcount)
1966 * If @return is not erroneous, the caller is responsible to decrement the
1967 * refcount by tty_driver_kref_put.
1969 * Locking: tty_mutex protects get_tty_driver
1971 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1974 struct tty_driver *driver;
1978 case MKDEV(TTY_MAJOR, 0): {
1979 extern struct tty_driver *console_driver;
1980 driver = tty_driver_kref_get(console_driver);
1981 *index = fg_console;
1985 case MKDEV(TTYAUX_MAJOR, 1): {
1986 struct tty_driver *console_driver = console_device(index);
1987 if (console_driver) {
1988 driver = tty_driver_kref_get(console_driver);
1990 /* Don't let /dev/console block */
1991 filp->f_flags |= O_NONBLOCK;
1995 return ERR_PTR(-ENODEV);
1998 driver = get_tty_driver(device, index);
2000 return ERR_PTR(-ENODEV);
2007 * tty_open_by_driver - open a tty device
2008 * @device: dev_t of device to open
2009 * @inode: inode of device file
2010 * @filp: file pointer to tty
2012 * Performs the driver lookup, checks for a reopen, or otherwise
2013 * performs the first-time tty initialization.
2015 * Returns the locked initialized or re-opened &tty_struct
2017 * Claims the global tty_mutex to serialize:
2018 * - concurrent first-time tty initialization
2019 * - concurrent tty driver removal w/ lookup
2020 * - concurrent tty removal from driver table
2022 static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
2025 struct tty_struct *tty;
2026 struct tty_driver *driver = NULL;
2030 mutex_lock(&tty_mutex);
2031 driver = tty_lookup_driver(device, filp, &index);
2032 if (IS_ERR(driver)) {
2033 mutex_unlock(&tty_mutex);
2034 return ERR_CAST(driver);
2037 /* check whether we're reopening an existing tty */
2038 tty = tty_driver_lookup_tty(driver, filp, index);
2040 mutex_unlock(&tty_mutex);
2045 mutex_unlock(&tty_mutex);
2046 retval = tty_lock_interruptible(tty);
2047 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2049 if (retval == -EINTR)
2050 retval = -ERESTARTSYS;
2051 tty = ERR_PTR(retval);
2054 retval = tty_reopen(tty);
2057 tty = ERR_PTR(retval);
2059 } else { /* Returns with the tty_lock held for now */
2060 tty = tty_init_dev(driver, index);
2061 mutex_unlock(&tty_mutex);
2064 tty_driver_kref_put(driver);
2069 * tty_open - open a tty device
2070 * @inode: inode of device file
2071 * @filp: file pointer to tty
2073 * tty_open and tty_release keep up the tty count that contains the
2074 * number of opens done on a tty. We cannot use the inode-count, as
2075 * different inodes might point to the same tty.
2077 * Open-counting is needed for pty masters, as well as for keeping
2078 * track of serial lines: DTR is dropped when the last close happens.
2079 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2081 * The termios state of a pty is reset on first open so that
2082 * settings don't persist across reuse.
2084 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2085 * tty->count should protect the rest.
2086 * ->siglock protects ->signal/->sighand
2088 * Note: the tty_unlock/lock cases without a ref are only safe due to
2092 static int tty_open(struct inode *inode, struct file *filp)
2094 struct tty_struct *tty;
2096 dev_t device = inode->i_rdev;
2097 unsigned saved_flags = filp->f_flags;
2099 nonseekable_open(inode, filp);
2102 retval = tty_alloc_file(filp);
2106 tty = tty_open_current_tty(device, filp);
2108 tty = tty_open_by_driver(device, inode, filp);
2111 tty_free_file(filp);
2112 retval = PTR_ERR(tty);
2113 if (retval != -EAGAIN || signal_pending(current))
2119 tty_add_file(tty, filp);
2121 check_tty_count(tty, __func__);
2122 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2125 retval = tty->ops->open(tty, filp);
2128 filp->f_flags = saved_flags;
2131 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2133 tty_unlock(tty); /* need to call tty_release without BTM */
2134 tty_release(inode, filp);
2135 if (retval != -ERESTARTSYS)
2138 if (signal_pending(current))
2143 * Need to reset f_op in case a hangup happened.
2145 if (tty_hung_up_p(filp))
2146 filp->f_op = &tty_fops;
2149 clear_bit(TTY_HUPPED, &tty->flags);
2152 read_lock(&tasklist_lock);
2153 spin_lock_irq(¤t->sighand->siglock);
2154 noctty = (filp->f_flags & O_NOCTTY) ||
2155 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2156 device == MKDEV(TTYAUX_MAJOR, 1) ||
2157 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2158 tty->driver->subtype == PTY_TYPE_MASTER);
2161 current->signal->leader &&
2162 !current->signal->tty &&
2163 tty->session == NULL) {
2165 * Don't let a process that only has write access to the tty
2166 * obtain the privileges associated with having a tty as
2167 * controlling terminal (being able to reopen it with full
2168 * access through /dev/tty, being able to perform pushback).
2169 * Many distributions set the group of all ttys to "tty" and
2170 * grant write-only access to all terminals for setgid tty
2171 * binaries, which should not imply full privileges on all ttys.
2173 * This could theoretically break old code that performs open()
2174 * on a write-only file descriptor. In that case, it might be
2175 * necessary to also permit this if
2176 * inode_permission(inode, MAY_READ) == 0.
2178 if (filp->f_mode & FMODE_READ)
2179 __proc_set_tty(tty);
2181 spin_unlock_irq(¤t->sighand->siglock);
2182 read_unlock(&tasklist_lock);
2190 * tty_poll - check tty status
2191 * @filp: file being polled
2192 * @wait: poll wait structures to update
2194 * Call the line discipline polling method to obtain the poll
2195 * status of the device.
2197 * Locking: locks called line discipline but ldisc poll method
2198 * may be re-entered freely by other callers.
2201 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2203 struct tty_struct *tty = file_tty(filp);
2204 struct tty_ldisc *ld;
2207 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2210 ld = tty_ldisc_ref_wait(tty);
2212 return hung_up_tty_poll(filp, wait);
2214 ret = ld->ops->poll(tty, filp, wait);
2215 tty_ldisc_deref(ld);
2219 static int __tty_fasync(int fd, struct file *filp, int on)
2221 struct tty_struct *tty = file_tty(filp);
2222 unsigned long flags;
2225 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2228 retval = fasync_helper(fd, filp, on, &tty->fasync);
2236 spin_lock_irqsave(&tty->ctrl_lock, flags);
2239 type = PIDTYPE_PGID;
2241 pid = task_pid(current);
2245 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2246 __f_setown(filp, pid, type, 0);
2254 static int tty_fasync(int fd, struct file *filp, int on)
2256 struct tty_struct *tty = file_tty(filp);
2257 int retval = -ENOTTY;
2260 if (!tty_hung_up_p(filp))
2261 retval = __tty_fasync(fd, filp, on);
2268 * tiocsti - fake input character
2269 * @tty: tty to fake input into
2270 * @p: pointer to character
2272 * Fake input to a tty device. Does the necessary locking and
2275 * FIXME: does not honour flow control ??
2278 * Called functions take tty_ldiscs_lock
2279 * current->signal->tty check is safe without locks
2281 * FIXME: may race normal receive processing
2284 static int tiocsti(struct tty_struct *tty, char __user *p)
2287 struct tty_ldisc *ld;
2289 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2291 if (get_user(ch, p))
2293 tty_audit_tiocsti(tty, ch);
2294 ld = tty_ldisc_ref_wait(tty);
2297 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2298 tty_ldisc_deref(ld);
2303 * tiocgwinsz - implement window query ioctl
2305 * @arg: user buffer for result
2307 * Copies the kernel idea of the window size into the user buffer.
2309 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2313 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2317 mutex_lock(&tty->winsize_mutex);
2318 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2319 mutex_unlock(&tty->winsize_mutex);
2321 return err ? -EFAULT: 0;
2325 * tty_do_resize - resize event
2326 * @tty: tty being resized
2327 * @rows: rows (character)
2328 * @cols: cols (character)
2330 * Update the termios variables and send the necessary signals to
2331 * peform a terminal resize correctly
2334 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2339 mutex_lock(&tty->winsize_mutex);
2340 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2343 /* Signal the foreground process group */
2344 pgrp = tty_get_pgrp(tty);
2346 kill_pgrp(pgrp, SIGWINCH, 1);
2351 mutex_unlock(&tty->winsize_mutex);
2354 EXPORT_SYMBOL(tty_do_resize);
2357 * tiocswinsz - implement window size set ioctl
2358 * @tty; tty side of tty
2359 * @arg: user buffer for result
2361 * Copies the user idea of the window size to the kernel. Traditionally
2362 * this is just advisory information but for the Linux console it
2363 * actually has driver level meaning and triggers a VC resize.
2366 * Driver dependent. The default do_resize method takes the
2367 * tty termios mutex and ctrl_lock. The console takes its own lock
2368 * then calls into the default method.
2371 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2373 struct winsize tmp_ws;
2374 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2377 if (tty->ops->resize)
2378 return tty->ops->resize(tty, &tmp_ws);
2380 return tty_do_resize(tty, &tmp_ws);
2384 * tioccons - allow admin to move logical console
2385 * @file: the file to become console
2387 * Allow the administrator to move the redirected console device
2389 * Locking: uses redirect_lock to guard the redirect information
2392 static int tioccons(struct file *file)
2394 if (!capable(CAP_SYS_ADMIN))
2396 if (file->f_op->write == redirected_tty_write) {
2398 spin_lock(&redirect_lock);
2401 spin_unlock(&redirect_lock);
2406 spin_lock(&redirect_lock);
2408 spin_unlock(&redirect_lock);
2411 redirect = get_file(file);
2412 spin_unlock(&redirect_lock);
2417 * fionbio - non blocking ioctl
2418 * @file: file to set blocking value
2419 * @p: user parameter
2421 * Historical tty interfaces had a blocking control ioctl before
2422 * the generic functionality existed. This piece of history is preserved
2423 * in the expected tty API of posix OS's.
2425 * Locking: none, the open file handle ensures it won't go away.
2428 static int fionbio(struct file *file, int __user *p)
2432 if (get_user(nonblock, p))
2435 spin_lock(&file->f_lock);
2437 file->f_flags |= O_NONBLOCK;
2439 file->f_flags &= ~O_NONBLOCK;
2440 spin_unlock(&file->f_lock);
2445 * tiocsctty - set controlling tty
2446 * @tty: tty structure
2447 * @arg: user argument
2449 * This ioctl is used to manage job control. It permits a session
2450 * leader to set this tty as the controlling tty for the session.
2453 * Takes tty_lock() to serialize proc_set_tty() for this tty
2454 * Takes tasklist_lock internally to walk sessions
2455 * Takes ->siglock() when updating signal->tty
2458 static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2463 read_lock(&tasklist_lock);
2465 if (current->signal->leader && (task_session(current) == tty->session))
2469 * The process must be a session leader and
2470 * not have a controlling tty already.
2472 if (!current->signal->leader || current->signal->tty) {
2479 * This tty is already the controlling
2480 * tty for another session group!
2482 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2486 session_clear_tty(tty->session);
2493 /* See the comment in tty_open(). */
2494 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2501 read_unlock(&tasklist_lock);
2507 * tty_get_pgrp - return a ref counted pgrp pid
2510 * Returns a refcounted instance of the pid struct for the process
2511 * group controlling the tty.
2514 struct pid *tty_get_pgrp(struct tty_struct *tty)
2516 unsigned long flags;
2519 spin_lock_irqsave(&tty->ctrl_lock, flags);
2520 pgrp = get_pid(tty->pgrp);
2521 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2525 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2528 * This checks not only the pgrp, but falls back on the pid if no
2529 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2532 * The caller must hold rcu lock or the tasklist lock.
2534 static struct pid *session_of_pgrp(struct pid *pgrp)
2536 struct task_struct *p;
2537 struct pid *sid = NULL;
2539 p = pid_task(pgrp, PIDTYPE_PGID);
2541 p = pid_task(pgrp, PIDTYPE_PID);
2543 sid = task_session(p);
2549 * tiocgpgrp - get process group
2550 * @tty: tty passed by user
2551 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2554 * Obtain the process group of the tty. If there is no process group
2557 * Locking: none. Reference to current->signal->tty is safe.
2560 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2565 * (tty == real_tty) is a cheap way of
2566 * testing if the tty is NOT a master pty.
2568 if (tty == real_tty && current->signal->tty != real_tty)
2570 pid = tty_get_pgrp(real_tty);
2571 ret = put_user(pid_vnr(pid), p);
2577 * tiocspgrp - attempt to set process group
2578 * @tty: tty passed by user
2579 * @real_tty: tty side device matching tty passed by user
2582 * Set the process group of the tty to the session passed. Only
2583 * permitted where the tty session is our session.
2585 * Locking: RCU, ctrl lock
2588 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2592 int retval = tty_check_change(real_tty);
2598 if (!current->signal->tty ||
2599 (current->signal->tty != real_tty) ||
2600 (real_tty->session != task_session(current)))
2602 if (get_user(pgrp_nr, p))
2607 pgrp = find_vpid(pgrp_nr);
2612 if (session_of_pgrp(pgrp) != task_session(current))
2615 spin_lock_irq(&tty->ctrl_lock);
2616 put_pid(real_tty->pgrp);
2617 real_tty->pgrp = get_pid(pgrp);
2618 spin_unlock_irq(&tty->ctrl_lock);
2625 * tiocgsid - get session id
2626 * @tty: tty passed by user
2627 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2628 * @p: pointer to returned session id
2630 * Obtain the session id of the tty. If there is no session
2633 * Locking: none. Reference to current->signal->tty is safe.
2636 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2639 * (tty == real_tty) is a cheap way of
2640 * testing if the tty is NOT a master pty.
2642 if (tty == real_tty && current->signal->tty != real_tty)
2644 if (!real_tty->session)
2646 return put_user(pid_vnr(real_tty->session), p);
2650 * tiocsetd - set line discipline
2652 * @p: pointer to user data
2654 * Set the line discipline according to user request.
2656 * Locking: see tty_set_ldisc, this function is just a helper
2659 static int tiocsetd(struct tty_struct *tty, int __user *p)
2664 if (get_user(disc, p))
2667 ret = tty_set_ldisc(tty, disc);
2673 * tiocgetd - get line discipline
2675 * @p: pointer to user data
2677 * Retrieves the line discipline id directly from the ldisc.
2679 * Locking: waits for ldisc reference (in case the line discipline
2680 * is changing or the tty is being hungup)
2683 static int tiocgetd(struct tty_struct *tty, int __user *p)
2685 struct tty_ldisc *ld;
2688 ld = tty_ldisc_ref_wait(tty);
2691 ret = put_user(ld->ops->num, p);
2692 tty_ldisc_deref(ld);
2697 * send_break - performed time break
2698 * @tty: device to break on
2699 * @duration: timeout in mS
2701 * Perform a timed break on hardware that lacks its own driver level
2702 * timed break functionality.
2705 * atomic_write_lock serializes
2709 static int send_break(struct tty_struct *tty, unsigned int duration)
2713 if (tty->ops->break_ctl == NULL)
2716 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2717 retval = tty->ops->break_ctl(tty, duration);
2719 /* Do the work ourselves */
2720 if (tty_write_lock(tty, 0) < 0)
2722 retval = tty->ops->break_ctl(tty, -1);
2725 if (!signal_pending(current))
2726 msleep_interruptible(duration);
2727 retval = tty->ops->break_ctl(tty, 0);
2729 tty_write_unlock(tty);
2730 if (signal_pending(current))
2737 * tty_tiocmget - get modem status
2739 * @file: user file pointer
2740 * @p: pointer to result
2742 * Obtain the modem status bits from the tty driver if the feature
2743 * is supported. Return -EINVAL if it is not available.
2745 * Locking: none (up to the driver)
2748 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2750 int retval = -EINVAL;
2752 if (tty->ops->tiocmget) {
2753 retval = tty->ops->tiocmget(tty);
2756 retval = put_user(retval, p);
2762 * tty_tiocmset - set modem status
2764 * @cmd: command - clear bits, set bits or set all
2765 * @p: pointer to desired bits
2767 * Set the modem status bits from the tty driver if the feature
2768 * is supported. Return -EINVAL if it is not available.
2770 * Locking: none (up to the driver)
2773 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2777 unsigned int set, clear, val;
2779 if (tty->ops->tiocmset == NULL)
2782 retval = get_user(val, p);
2798 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2799 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2800 return tty->ops->tiocmset(tty, set, clear);
2803 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2805 int retval = -EINVAL;
2806 struct serial_icounter_struct icount;
2807 memset(&icount, 0, sizeof(icount));
2808 if (tty->ops->get_icount)
2809 retval = tty->ops->get_icount(tty, &icount);
2812 if (copy_to_user(arg, &icount, sizeof(icount)))
2817 static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2819 static DEFINE_RATELIMIT_STATE(depr_flags,
2820 DEFAULT_RATELIMIT_INTERVAL,
2821 DEFAULT_RATELIMIT_BURST);
2822 char comm[TASK_COMM_LEN];
2825 if (get_user(flags, &ss->flags))
2828 flags &= ASYNC_DEPRECATED;
2830 if (flags && __ratelimit(&depr_flags))
2831 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2832 __func__, get_task_comm(comm, current), flags);
2836 * if pty, return the slave side (real_tty)
2837 * otherwise, return self
2839 static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2841 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2842 tty->driver->subtype == PTY_TYPE_MASTER)
2848 * Split this up, as gcc can choke on it otherwise..
2850 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2852 struct tty_struct *tty = file_tty(file);
2853 struct tty_struct *real_tty;
2854 void __user *p = (void __user *)arg;
2856 struct tty_ldisc *ld;
2858 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2861 real_tty = tty_pair_get_tty(tty);
2864 * Factor out some common prep work
2872 retval = tty_check_change(tty);
2875 if (cmd != TIOCCBRK) {
2876 tty_wait_until_sent(tty, 0);
2877 if (signal_pending(current))
2888 return tiocsti(tty, p);
2890 return tiocgwinsz(real_tty, p);
2892 return tiocswinsz(real_tty, p);
2894 return real_tty != tty ? -EINVAL : tioccons(file);
2896 return fionbio(file, p);
2898 set_bit(TTY_EXCLUSIVE, &tty->flags);
2901 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2905 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2906 return put_user(excl, (int __user *)p);
2909 if (current->signal->tty != tty)
2914 return tiocsctty(real_tty, file, arg);
2916 return tiocgpgrp(tty, real_tty, p);
2918 return tiocspgrp(tty, real_tty, p);
2920 return tiocgsid(tty, real_tty, p);
2922 return tiocgetd(tty, p);
2924 return tiocsetd(tty, p);
2926 if (!capable(CAP_SYS_ADMIN))
2932 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2933 return put_user(ret, (unsigned int __user *)p);
2938 case TIOCSBRK: /* Turn break on, unconditionally */
2939 if (tty->ops->break_ctl)
2940 return tty->ops->break_ctl(tty, -1);
2942 case TIOCCBRK: /* Turn break off, unconditionally */
2943 if (tty->ops->break_ctl)
2944 return tty->ops->break_ctl(tty, 0);
2946 case TCSBRK: /* SVID version: non-zero arg --> no break */
2947 /* non-zero arg means wait for all output data
2948 * to be sent (performed above) but don't send break.
2949 * This is used by the tcdrain() termios function.
2952 return send_break(tty, 250);
2954 case TCSBRKP: /* support for POSIX tcsendbreak() */
2955 return send_break(tty, arg ? arg*100 : 250);
2958 return tty_tiocmget(tty, p);
2962 return tty_tiocmset(tty, cmd, p);
2964 retval = tty_tiocgicount(tty, p);
2965 /* For the moment allow fall through to the old method */
2966 if (retval != -EINVAL)
2973 /* flush tty buffer and allow ldisc to process ioctl */
2974 tty_buffer_flush(tty, NULL);
2979 tty_warn_deprecated_flags(p);
2982 if (tty->ops->ioctl) {
2983 retval = tty->ops->ioctl(tty, cmd, arg);
2984 if (retval != -ENOIOCTLCMD)
2987 ld = tty_ldisc_ref_wait(tty);
2989 return hung_up_tty_ioctl(file, cmd, arg);
2991 if (ld->ops->ioctl) {
2992 retval = ld->ops->ioctl(tty, file, cmd, arg);
2993 if (retval == -ENOIOCTLCMD)
2996 tty_ldisc_deref(ld);
3000 #ifdef CONFIG_COMPAT
3001 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
3004 struct tty_struct *tty = file_tty(file);
3005 struct tty_ldisc *ld;
3006 int retval = -ENOIOCTLCMD;
3008 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
3011 if (tty->ops->compat_ioctl) {
3012 retval = tty->ops->compat_ioctl(tty, cmd, arg);
3013 if (retval != -ENOIOCTLCMD)
3017 ld = tty_ldisc_ref_wait(tty);
3019 return hung_up_tty_compat_ioctl(file, cmd, arg);
3020 if (ld->ops->compat_ioctl)
3021 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
3023 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
3024 tty_ldisc_deref(ld);
3030 static int this_tty(const void *t, struct file *file, unsigned fd)
3032 if (likely(file->f_op->read != tty_read))
3034 return file_tty(file) != t ? 0 : fd + 1;
3038 * This implements the "Secure Attention Key" --- the idea is to
3039 * prevent trojan horses by killing all processes associated with this
3040 * tty when the user hits the "Secure Attention Key". Required for
3041 * super-paranoid applications --- see the Orange Book for more details.
3043 * This code could be nicer; ideally it should send a HUP, wait a few
3044 * seconds, then send a INT, and then a KILL signal. But you then
3045 * have to coordinate with the init process, since all processes associated
3046 * with the current tty must be dead before the new getty is allowed
3049 * Now, if it would be correct ;-/ The current code has a nasty hole -
3050 * it doesn't catch files in flight. We may send the descriptor to ourselves
3051 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3053 * Nasty bug: do_SAK is being called in interrupt context. This can
3054 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3056 void __do_SAK(struct tty_struct *tty)
3061 struct task_struct *g, *p;
3062 struct pid *session;
3067 session = tty->session;
3069 tty_ldisc_flush(tty);
3071 tty_driver_flush_buffer(tty);
3073 read_lock(&tasklist_lock);
3074 /* Kill the entire session */
3075 do_each_pid_task(session, PIDTYPE_SID, p) {
3076 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3077 task_pid_nr(p), p->comm);
3078 send_sig(SIGKILL, p, 1);
3079 } while_each_pid_task(session, PIDTYPE_SID, p);
3081 /* Now kill any processes that happen to have the tty open */
3082 do_each_thread(g, p) {
3083 if (p->signal->tty == tty) {
3084 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3085 task_pid_nr(p), p->comm);
3086 send_sig(SIGKILL, p, 1);
3090 i = iterate_fd(p->files, 0, this_tty, tty);
3092 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3093 task_pid_nr(p), p->comm, i - 1);
3094 force_sig(SIGKILL, p);
3097 } while_each_thread(g, p);
3098 read_unlock(&tasklist_lock);
3102 static void do_SAK_work(struct work_struct *work)
3104 struct tty_struct *tty =
3105 container_of(work, struct tty_struct, SAK_work);
3110 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3111 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3112 * the values which we write to it will be identical to the values which it
3113 * already has. --akpm
3115 void do_SAK(struct tty_struct *tty)
3119 schedule_work(&tty->SAK_work);
3122 EXPORT_SYMBOL(do_SAK);
3124 static int dev_match_devt(struct device *dev, const void *data)
3126 const dev_t *devt = data;
3127 return dev->devt == *devt;
3130 /* Must put_device() after it's unused! */
3131 static struct device *tty_get_device(struct tty_struct *tty)
3133 dev_t devt = tty_devnum(tty);
3134 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3141 * This subroutine allocates and initializes a tty structure.
3143 * Locking: none - tty in question is not exposed at this point
3146 struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3148 struct tty_struct *tty;
3150 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3154 kref_init(&tty->kref);
3155 tty->magic = TTY_MAGIC;
3156 tty_ldisc_init(tty);
3157 tty->session = NULL;
3159 mutex_init(&tty->legacy_mutex);
3160 mutex_init(&tty->throttle_mutex);
3161 init_rwsem(&tty->termios_rwsem);
3162 mutex_init(&tty->winsize_mutex);
3163 init_ldsem(&tty->ldisc_sem);
3164 init_waitqueue_head(&tty->write_wait);
3165 init_waitqueue_head(&tty->read_wait);
3166 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3167 mutex_init(&tty->atomic_write_lock);
3168 spin_lock_init(&tty->ctrl_lock);
3169 spin_lock_init(&tty->flow_lock);
3170 spin_lock_init(&tty->files_lock);
3171 INIT_LIST_HEAD(&tty->tty_files);
3172 INIT_WORK(&tty->SAK_work, do_SAK_work);
3174 tty->driver = driver;
3175 tty->ops = driver->ops;
3177 tty_line_name(driver, idx, tty->name);
3178 tty->dev = tty_get_device(tty);
3184 * tty_put_char - write one character to a tty
3188 * Write one byte to the tty using the provided put_char method
3189 * if present. Returns the number of characters successfully output.
3191 * Note: the specific put_char operation in the driver layer may go
3192 * away soon. Don't call it directly, use this method
3195 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3197 if (tty->ops->put_char)
3198 return tty->ops->put_char(tty, ch);
3199 return tty->ops->write(tty, &ch, 1);
3201 EXPORT_SYMBOL_GPL(tty_put_char);
3203 struct class *tty_class;
3205 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3206 unsigned int index, unsigned int count)
3210 /* init here, since reused cdevs cause crashes */
3211 driver->cdevs[index] = cdev_alloc();
3212 if (!driver->cdevs[index])
3214 driver->cdevs[index]->ops = &tty_fops;
3215 driver->cdevs[index]->owner = driver->owner;
3216 err = cdev_add(driver->cdevs[index], dev, count);
3218 kobject_put(&driver->cdevs[index]->kobj);
3223 * tty_register_device - register a tty device
3224 * @driver: the tty driver that describes the tty device
3225 * @index: the index in the tty driver for this tty device
3226 * @device: a struct device that is associated with this tty device.
3227 * This field is optional, if there is no known struct device
3228 * for this tty device it can be set to NULL safely.
3230 * Returns a pointer to the struct device for this tty device
3231 * (or ERR_PTR(-EFOO) on error).
3233 * This call is required to be made to register an individual tty device
3234 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3235 * that bit is not set, this function should not be called by a tty
3241 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3242 struct device *device)
3244 return tty_register_device_attr(driver, index, device, NULL, NULL);
3246 EXPORT_SYMBOL(tty_register_device);
3248 static void tty_device_create_release(struct device *dev)
3250 dev_dbg(dev, "releasing...\n");
3255 * tty_register_device_attr - register a tty device
3256 * @driver: the tty driver that describes the tty device
3257 * @index: the index in the tty driver for this tty device
3258 * @device: a struct device that is associated with this tty device.
3259 * This field is optional, if there is no known struct device
3260 * for this tty device it can be set to NULL safely.
3261 * @drvdata: Driver data to be set to device.
3262 * @attr_grp: Attribute group to be set on device.
3264 * Returns a pointer to the struct device for this tty device
3265 * (or ERR_PTR(-EFOO) on error).
3267 * This call is required to be made to register an individual tty device
3268 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3269 * that bit is not set, this function should not be called by a tty
3274 struct device *tty_register_device_attr(struct tty_driver *driver,
3275 unsigned index, struct device *device,
3277 const struct attribute_group **attr_grp)
3280 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3281 struct device *dev = NULL;
3282 int retval = -ENODEV;
3285 if (index >= driver->num) {
3286 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3287 driver->name, index);
3288 return ERR_PTR(-EINVAL);
3291 if (driver->type == TTY_DRIVER_TYPE_PTY)
3292 pty_line_name(driver, index, name);
3294 tty_line_name(driver, index, name);
3296 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3297 retval = tty_cdev_add(driver, devt, index, 1);
3303 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3310 dev->class = tty_class;
3311 dev->parent = device;
3312 dev->release = tty_device_create_release;
3313 dev_set_name(dev, "%s", name);
3314 dev->groups = attr_grp;
3315 dev_set_drvdata(dev, drvdata);
3317 retval = device_register(dev);
3326 cdev_del(driver->cdevs[index]);
3327 driver->cdevs[index] = NULL;
3329 return ERR_PTR(retval);
3331 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3334 * tty_unregister_device - unregister a tty device
3335 * @driver: the tty driver that describes the tty device
3336 * @index: the index in the tty driver for this tty device
3338 * If a tty device is registered with a call to tty_register_device() then
3339 * this function must be called when the tty device is gone.
3344 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3346 device_destroy(tty_class,
3347 MKDEV(driver->major, driver->minor_start) + index);
3348 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3349 cdev_del(driver->cdevs[index]);
3350 driver->cdevs[index] = NULL;
3353 EXPORT_SYMBOL(tty_unregister_device);
3356 * __tty_alloc_driver -- allocate tty driver
3357 * @lines: count of lines this driver can handle at most
3358 * @owner: module which is repsonsible for this driver
3359 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3361 * This should not be called directly, some of the provided macros should be
3362 * used instead. Use IS_ERR and friends on @retval.
3364 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3365 unsigned long flags)
3367 struct tty_driver *driver;
3368 unsigned int cdevs = 1;
3371 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3372 return ERR_PTR(-EINVAL);
3374 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3376 return ERR_PTR(-ENOMEM);
3378 kref_init(&driver->kref);
3379 driver->magic = TTY_DRIVER_MAGIC;
3380 driver->num = lines;
3381 driver->owner = owner;
3382 driver->flags = flags;
3384 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3385 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3387 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3389 if (!driver->ttys || !driver->termios) {
3395 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3396 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3398 if (!driver->ports) {
3405 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3406 if (!driver->cdevs) {
3413 kfree(driver->ports);
3414 kfree(driver->ttys);
3415 kfree(driver->termios);
3416 kfree(driver->cdevs);
3418 return ERR_PTR(err);
3420 EXPORT_SYMBOL(__tty_alloc_driver);
3422 static void destruct_tty_driver(struct kref *kref)
3424 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3426 struct ktermios *tp;
3428 if (driver->flags & TTY_DRIVER_INSTALLED) {
3430 * Free the termios and termios_locked structures because
3431 * we don't want to get memory leaks when modular tty
3432 * drivers are removed from the kernel.
3434 for (i = 0; i < driver->num; i++) {
3435 tp = driver->termios[i];
3437 driver->termios[i] = NULL;
3440 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3441 tty_unregister_device(driver, i);
3443 proc_tty_unregister_driver(driver);
3444 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3445 cdev_del(driver->cdevs[0]);
3447 kfree(driver->cdevs);
3448 kfree(driver->ports);
3449 kfree(driver->termios);
3450 kfree(driver->ttys);
3454 void tty_driver_kref_put(struct tty_driver *driver)
3456 kref_put(&driver->kref, destruct_tty_driver);
3458 EXPORT_SYMBOL(tty_driver_kref_put);
3460 void tty_set_operations(struct tty_driver *driver,
3461 const struct tty_operations *op)
3465 EXPORT_SYMBOL(tty_set_operations);
3467 void put_tty_driver(struct tty_driver *d)
3469 tty_driver_kref_put(d);
3471 EXPORT_SYMBOL(put_tty_driver);
3474 * Called by a tty driver to register itself.
3476 int tty_register_driver(struct tty_driver *driver)
3483 if (!driver->major) {
3484 error = alloc_chrdev_region(&dev, driver->minor_start,
3485 driver->num, driver->name);
3487 driver->major = MAJOR(dev);
3488 driver->minor_start = MINOR(dev);
3491 dev = MKDEV(driver->major, driver->minor_start);
3492 error = register_chrdev_region(dev, driver->num, driver->name);
3497 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3498 error = tty_cdev_add(driver, dev, 0, driver->num);
3500 goto err_unreg_char;
3503 mutex_lock(&tty_mutex);
3504 list_add(&driver->tty_drivers, &tty_drivers);
3505 mutex_unlock(&tty_mutex);
3507 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3508 for (i = 0; i < driver->num; i++) {
3509 d = tty_register_device(driver, i, NULL);
3512 goto err_unreg_devs;
3516 proc_tty_register_driver(driver);
3517 driver->flags |= TTY_DRIVER_INSTALLED;
3521 for (i--; i >= 0; i--)
3522 tty_unregister_device(driver, i);
3524 mutex_lock(&tty_mutex);
3525 list_del(&driver->tty_drivers);
3526 mutex_unlock(&tty_mutex);
3529 unregister_chrdev_region(dev, driver->num);
3533 EXPORT_SYMBOL(tty_register_driver);
3536 * Called by a tty driver to unregister itself.
3538 int tty_unregister_driver(struct tty_driver *driver)
3542 if (driver->refcount)
3545 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3547 mutex_lock(&tty_mutex);
3548 list_del(&driver->tty_drivers);
3549 mutex_unlock(&tty_mutex);
3553 EXPORT_SYMBOL(tty_unregister_driver);
3555 dev_t tty_devnum(struct tty_struct *tty)
3557 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3559 EXPORT_SYMBOL(tty_devnum);
3561 void tty_default_fops(struct file_operations *fops)
3567 * Initialize the console device. This is called *early*, so
3568 * we can't necessarily depend on lots of kernel help here.
3569 * Just do some early initializations, and do the complex setup
3572 void __init console_init(void)
3576 /* Setup the default TTY line discipline. */
3580 * set up the console device so that later boot sequences can
3581 * inform about problems etc..
3583 call = __con_initcall_start;
3584 while (call < __con_initcall_end) {
3590 static char *tty_devnode(struct device *dev, umode_t *mode)
3594 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3595 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3600 static int __init tty_class_init(void)
3602 tty_class = class_create(THIS_MODULE, "tty");
3603 if (IS_ERR(tty_class))
3604 return PTR_ERR(tty_class);
3605 tty_class->devnode = tty_devnode;
3609 postcore_initcall(tty_class_init);
3611 /* 3/2004 jmc: why do these devices exist? */
3612 static struct cdev tty_cdev, console_cdev;
3614 static ssize_t show_cons_active(struct device *dev,
3615 struct device_attribute *attr, char *buf)
3617 struct console *cs[16];
3623 for_each_console(c) {
3628 if ((c->flags & CON_ENABLED) == 0)
3631 if (i >= ARRAY_SIZE(cs))
3635 int index = cs[i]->index;
3636 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3638 /* don't resolve tty0 as some programs depend on it */
3639 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3640 count += tty_line_name(drv, index, buf + count);
3642 count += sprintf(buf + count, "%s%d",
3643 cs[i]->name, cs[i]->index);
3645 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3651 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3653 static struct attribute *cons_dev_attrs[] = {
3654 &dev_attr_active.attr,
3658 ATTRIBUTE_GROUPS(cons_dev);
3660 static struct device *consdev;
3662 void console_sysfs_notify(void)
3665 sysfs_notify(&consdev->kobj, NULL, "active");
3669 * Ok, now we can initialize the rest of the tty devices and can count
3670 * on memory allocations, interrupts etc..
3672 int __init tty_init(void)
3674 cdev_init(&tty_cdev, &tty_fops);
3675 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3676 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3677 panic("Couldn't register /dev/tty driver\n");
3678 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3680 cdev_init(&console_cdev, &console_fops);
3681 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3682 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3683 panic("Couldn't register /dev/console driver\n");
3684 consdev = device_create_with_groups(tty_class, NULL,
3685 MKDEV(TTYAUX_MAJOR, 1), NULL,
3686 cons_dev_groups, "console");
3687 if (IS_ERR(consdev))
3691 vty_init(&console_fops);