11 #include <linux/tty.h>
14 #include "tty.h"
24  *	@tty: tty to check
33 int __tty_check_change(struct tty_struct *tty, int sig)  in __tty_check_change()  argument
39 	if (current->signal->tty != tty)  in __tty_check_change()
45 	spin_lock_irqsave(&tty->ctrl.lock, flags);  in __tty_check_change()
46 	tty_pgrp = tty->ctrl.pgrp;  in __tty_check_change()
47 	spin_unlock_irqrestore(&tty->ctrl.lock, flags);  in __tty_check_change()
64 		tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);  in __tty_check_change()
69 int tty_check_change(struct tty_struct *tty)  in tty_check_change()  argument
71 	return __tty_check_change(tty, SIGTTOU);  in tty_check_change()
78 	struct tty_struct *tty;  in proc_clear_tty()  local
81 	tty = p->signal->tty;  in proc_clear_tty()
82 	p->signal->tty = NULL;  in proc_clear_tty()
84 	tty_kref_put(tty);  in proc_clear_tty()
89  *	@tty: tty structure
98 static void __proc_set_tty(struct tty_struct *tty)  in __proc_set_tty()  argument
102 	spin_lock_irqsave(&tty->ctrl.lock, flags);  in __proc_set_tty()
105 	 * tiocsctty() is stealing the controlling tty  in __proc_set_tty()
107 	put_pid(tty->ctrl.session);  in __proc_set_tty()
108 	put_pid(tty->ctrl.pgrp);  in __proc_set_tty()
109 	tty->ctrl.pgrp = get_pid(task_pgrp(current));  in __proc_set_tty()
110 	tty->ctrl.session = get_pid(task_session(current));  in __proc_set_tty()
111 	spin_unlock_irqrestore(&tty->ctrl.lock, flags);  in __proc_set_tty()
112 	if (current->signal->tty) {  in __proc_set_tty()
113 		tty_debug(tty, "current tty %s not NULL!!\n",  in __proc_set_tty()
114 			  current->signal->tty->name);  in __proc_set_tty()
115 		tty_kref_put(current->signal->tty);  in __proc_set_tty()
118 	current->signal->tty = tty_kref_get(tty);  in __proc_set_tty()
122 static void proc_set_tty(struct tty_struct *tty)  in proc_set_tty()  argument
125 	__proc_set_tty(tty);  in proc_set_tty()
130  * Called by tty_open() to set the controlling tty if applicable.
132 void tty_open_proc_set_tty(struct file *filp, struct tty_struct *tty)  in tty_open_proc_set_tty()  argument
137 	    !current->signal->tty &&  in tty_open_proc_set_tty()
138 	    tty->ctrl.session == NULL) {  in tty_open_proc_set_tty()
140 		 * Don't let a process that only has write access to the tty  in tty_open_proc_set_tty()
141 		 * obtain the privileges associated with having a tty as  in tty_open_proc_set_tty()
143 		 * access through /dev/tty, being able to perform pushback).  in tty_open_proc_set_tty()
144 		 * Many distributions set the group of all ttys to "tty" and  in tty_open_proc_set_tty()
145 		 * grant write-only access to all terminals for setgid tty  in tty_open_proc_set_tty()
154 			__proc_set_tty(tty);  in tty_open_proc_set_tty()
162 	struct tty_struct *tty;  in get_current_tty()  local
166 	tty = tty_kref_get(current->signal->tty);  in get_current_tty()
168 	return tty;  in get_current_tty()
186  *	@tty: controlling tty
192  *	Returns the number of processes in the session with this tty
194  *	tty references for those processes.
196 int tty_signal_session_leader(struct tty_struct *tty, int exit_session)  in tty_signal_session_leader()  argument
203 	if (tty->ctrl.session) {  in tty_signal_session_leader()
204 		do_each_pid_task(tty->ctrl.session, PIDTYPE_SID, p) {  in tty_signal_session_leader()
206 			if (p->signal->tty == tty) {  in tty_signal_session_leader()
207 				p->signal->tty = NULL;  in tty_signal_session_leader()
221 			spin_lock(&tty->ctrl.lock);  in tty_signal_session_leader()
222 			tty_pgrp = get_pid(tty->ctrl.pgrp);  in tty_signal_session_leader()
223 			if (tty->ctrl.pgrp)  in tty_signal_session_leader()
225 					get_pid(tty->ctrl.pgrp);  in tty_signal_session_leader()
226 			spin_unlock(&tty->ctrl.lock);  in tty_signal_session_leader()
228 		} while_each_pid_task(tty->ctrl.session, PIDTYPE_SID, p);  in tty_signal_session_leader()
242  *	disassociate_ctty	-	disconnect controlling tty
246  *	it wants to disassociate itself from its controlling tty.
250  *	(2)  Clears the tty from being controlling the session
251  *	(3)  Clears the controlling tty for all processes in the
260  *		  tty_mutex is taken to protect tty
267 	struct tty_struct *tty;  in disassociate_ctty()  local
272 	tty = get_current_tty();  in disassociate_ctty()
273 	if (tty) {  in disassociate_ctty()
274 		if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {  in disassociate_ctty()
275 			tty_vhangup_session(tty);  in disassociate_ctty()
277 			struct pid *tty_pgrp = tty_get_pgrp(tty);  in disassociate_ctty()
286 		tty_kref_put(tty);  in disassociate_ctty()
303 	tty = get_current_tty();  in disassociate_ctty()
304 	if (tty) {  in disassociate_ctty()
307 		tty_lock(tty);  in disassociate_ctty()
308 		spin_lock_irqsave(&tty->ctrl.lock, flags);  in disassociate_ctty()
309 		put_pid(tty->ctrl.session);  in disassociate_ctty()
310 		put_pid(tty->ctrl.pgrp);  in disassociate_ctty()
311 		tty->ctrl.session = NULL;  in disassociate_ctty()
312 		tty->ctrl.pgrp = NULL;  in disassociate_ctty()
313 		spin_unlock_irqrestore(&tty->ctrl.lock, flags);  in disassociate_ctty()
314 		tty_unlock(tty);  in disassociate_ctty()
315 		tty_kref_put(tty);  in disassociate_ctty()
318 	/* If tty->ctrl.pgrp is not NULL, it may be assigned to  in disassociate_ctty()
321 	 * after tty->ctrl.pgrp set to NULL.  in disassociate_ctty()
328 	/* Now clear signal->tty under the lock */  in disassociate_ctty()
336  *	no_tty	- Ensure the current process does not have a controlling tty
352  *	tiocsctty	-	set controlling tty
353  *	@tty: tty structure
358  *	leader to set this tty as the controlling tty for the session.
361  *		Takes tty_lock() to serialize proc_set_tty() for this tty
363  *		Takes ->siglock() when updating signal->tty
365 static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)  in tiocsctty()  argument
369 	tty_lock(tty);  in tiocsctty()
373 			task_session(current) == tty->ctrl.session)  in tiocsctty()
378 	 * not have a controlling tty already.  in tiocsctty()
380 	if (!current->signal->leader || current->signal->tty) {  in tiocsctty()
385 	if (tty->ctrl.session) {  in tiocsctty()
387 		 * This tty is already the controlling  in tiocsctty()
388 		 * tty for another session group!  in tiocsctty()
394 			session_clear_tty(tty->ctrl.session);  in tiocsctty()
407 	proc_set_tty(tty);  in tiocsctty()
410 	tty_unlock(tty);  in tiocsctty()
416  *	@tty: tty to read
419  *	group controlling the tty.
421 struct pid *tty_get_pgrp(struct tty_struct *tty)  in tty_get_pgrp()  argument
426 	spin_lock_irqsave(&tty->ctrl.lock, flags);  in tty_get_pgrp()
427 	pgrp = get_pid(tty->ctrl.pgrp);  in tty_get_pgrp()
428 	spin_unlock_irqrestore(&tty->ctrl.lock, flags);  in tty_get_pgrp()
457  *	@tty: tty passed by user
458  *	@real_tty: tty side of the tty passed by the user if a pty else the tty
461  *	Obtain the process group of the tty. If there is no process group
464  *	Locking: none. Reference to current->signal->tty is safe.
466 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)  in tiocgpgrp()  argument
471 	 * (tty == real_tty) is a cheap way of  in tiocgpgrp()
472 	 * testing if the tty is NOT a master pty.  in tiocgpgrp()
474 	if (tty == real_tty && current->signal->tty != real_tty)  in tiocgpgrp()
484  *	@tty: tty passed by user
485  *	@real_tty: tty side device matching tty passed by user
488  *	Set the process group of the tty to the session passed. Only
489  *	permitted where the tty session is our session.
493 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)  in tiocspgrp()  argument
510 	if (!current->signal->tty ||  in tiocspgrp()
511 	    (current->signal->tty != real_tty) ||  in tiocspgrp()
536  *	@tty: tty passed by user
537  *	@real_tty: tty side of the tty passed by the user if a pty else the tty
540  *	Obtain the session id of the tty. If there is no session
543 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)  in tiocgsid()  argument
549 	 * (tty == real_tty) is a cheap way of  in tiocgsid()
550 	 * testing if the tty is NOT a master pty.  in tiocgsid()
552 	if (tty == real_tty && current->signal->tty != real_tty)  in tiocgsid()
569  * Called from tty_ioctl(). If tty is a pty then real_tty is the slave side,
570  * if not then tty == real_tty.
572 long tty_jobctrl_ioctl(struct tty_struct *tty, struct tty_struct *real_tty,  in tty_jobctrl_ioctl()  argument
579 		if (current->signal->tty != tty)  in tty_jobctrl_ioctl()
586 		return tiocgpgrp(tty, real_tty, p);  in tty_jobctrl_ioctl()
588 		return tiocspgrp(tty, real_tty, p);  in tty_jobctrl_ioctl()
590 		return tiocgsid(tty, real_tty, p);  in tty_jobctrl_ioctl()