1 // SPDX-License-Identifier: GPL-2.0
18 	return (sigismember(&current->blocked, sig) ||  in is_ignored()
19 		current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);  in is_ignored()
23  *	__tty_check_change	-	check for POSIX terminal changes
27  *	If we try to write to, or set the state of, a terminal and we're
28  *	not in the foreground, send a SIGTTOU.  If the signal is blocked or
31  *	Locking: ctrl.lock
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()
52 				ret = -EIO;  in __tty_check_change()
54 			ret = -EIO;  in __tty_check_change()
58 			ret = -ERESTARTSYS;  in __tty_check_change()
64 		tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);  in __tty_check_change()
80 	spin_lock_irqsave(&p->sighand->siglock, flags);  in proc_clear_tty()
81 	tty = p->signal->tty;  in proc_clear_tty()
82 	p->signal->tty = NULL;  in proc_clear_tty()
83 	spin_unlock_irqrestore(&p->sighand->siglock, flags);  in proc_clear_tty()
88  * __proc_set_tty -  set the controlling terminal
92  * a controlling terminal.
95  *		      a readlock on tasklist_lock
102 	spin_lock_irqsave(&tty->ctrl.lock, flags);  in __proc_set_tty()
104 	 * The session and fg pgrp references will be non-NULL if  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()
114 			  current->signal->tty->name);  in __proc_set_tty()
115 		tty_kref_put(current->signal->tty);  in __proc_set_tty()
117 	put_pid(current->signal->tty_old_pgrp);  in __proc_set_tty()
118 	current->signal->tty = tty_kref_get(tty);  in __proc_set_tty()
119 	current->signal->tty_old_pgrp = NULL;  in __proc_set_tty()
124 	spin_lock_irq(&current->sighand->siglock);  in proc_set_tty()
126 	spin_unlock_irq(&current->sighand->siglock);  in proc_set_tty()
135 	spin_lock_irq(&current->sighand->siglock);  in tty_open_proc_set_tty()
136 	if (current->signal->leader &&  in tty_open_proc_set_tty()
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()
145 		 * grant write-only access to all terminals for setgid tty  in tty_open_proc_set_tty()
149 		 * on a write-only file descriptor. In that case, it might be  in tty_open_proc_set_tty()
153 		if (filp->f_mode & FMODE_READ)  in tty_open_proc_set_tty()
156 	spin_unlock_irq(&current->sighand->siglock);  in tty_open_proc_set_tty()
165 	spin_lock_irqsave(&current->sighand->siglock, flags);  in get_current_tty()
166 	tty = tty_kref_get(current->signal->tty);  in get_current_tty()
167 	spin_unlock_irqrestore(&current->sighand->siglock, flags);  in get_current_tty()
185  *	tty_signal_session_leader	- sends SIGHUP to session leader
187  *	@exit_session: if non-zero, signal all foreground group processes
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()
205 			spin_lock_irq(&p->sighand->siglock);  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()
214 			if (!p->signal->leader) {  in tty_signal_session_leader()
215 				spin_unlock_irq(&p->sighand->siglock);  in tty_signal_session_leader()
220 			put_pid(p->signal->tty_old_pgrp);  /* A noop */  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()
224 				p->signal->tty_old_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()
227 			spin_unlock_irq(&p->sighand->siglock);  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
249  *	(1)  Sends a SIGHUP and SIGCONT to the foreground process group
254  *	The argument on_exit is set to 1 if called when a process is
261  *		  ->siglock is taken to protect ->signal/->sighand
263  *		    ->siglock is taken to protect ->signal/->sighand
269 	if (!current->signal->leader)  in disassociate_ctty()
274 		if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {  in disassociate_ctty()
291 		spin_lock_irq(&current->sighand->siglock);  in disassociate_ctty()
292 		old_pgrp = current->signal->tty_old_pgrp;  in disassociate_ctty()
293 		current->signal->tty_old_pgrp = NULL;  in disassociate_ctty()
294 		spin_unlock_irq(&current->sighand->siglock);  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()
318 	/* If tty->ctrl.pgrp is not NULL, it may be assigned to  in disassociate_ctty()
319 	 * current->signal->tty_old_pgrp in a race condition, and  in disassociate_ctty()
320 	 * cause pid memleak. Release current->signal->tty_old_pgrp  in disassociate_ctty()
321 	 * after tty->ctrl.pgrp set to NULL.  in disassociate_ctty()
323 	spin_lock_irq(&current->sighand->siglock);  in disassociate_ctty()
324 	put_pid(current->signal->tty_old_pgrp);  in disassociate_ctty()
325 	current->signal->tty_old_pgrp = NULL;  in disassociate_ctty()
326 	spin_unlock_irq(&current->sighand->siglock);  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
342 	 * between a new association and proc_clear_tty but possibly we need  in no_tty()
352  *	tiocsctty	-	set controlling tty
357  *	This ioctl is used to manage job control. It permits a session
363  *		Takes ->siglock() when updating signal->tty
372 	if (current->signal->leader &&  in tiocsctty()
373 			task_session(current) == tty->ctrl.session)  in tiocsctty()
377 	 * The process must be a session leader and  in tiocsctty()
378 	 * not have a controlling tty already.  in tiocsctty()
380 	if (!current->signal->leader || current->signal->tty) {  in tiocsctty()
381 		ret = -EPERM;  in tiocsctty()
385 	if (tty->ctrl.session) {  in tiocsctty()
394 			session_clear_tty(tty->ctrl.session);  in tiocsctty()
396 			ret = -EPERM;  in tiocsctty()
402 	if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {  in tiocsctty()
403 		ret = -EPERM;  in tiocsctty()
415  *	tty_get_pgrp	-	return a ref counted pgrp pid
418  *	Returns a refcounted instance of the pid struct for the process
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()
436  * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
456  *	tiocgpgrp		-	get process group
458  *	@real_tty: tty side of the tty passed by the user if a pty else the tty
464  *	Locking: none. Reference to current->signal->tty is safe.
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()
475 		return -ENOTTY;  in tiocgpgrp()
483  *	tiocspgrp		-	attempt to set process group
491  *	Locking: RCU, ctrl lock
499 	if (retval == -EIO)  in tiocspgrp()
500 		return -ENOTTY;  in tiocspgrp()
505 		return -EFAULT;  in tiocspgrp()
507 		return -EINVAL;  in tiocspgrp()
509 	spin_lock_irq(&real_tty->ctrl.lock);  in tiocspgrp()
510 	if (!current->signal->tty ||  in tiocspgrp()
511 	    (current->signal->tty != real_tty) ||  in tiocspgrp()
512 	    (real_tty->ctrl.session != task_session(current))) {  in tiocspgrp()
513 		retval = -ENOTTY;  in tiocspgrp()
518 	retval = -ESRCH;  in tiocspgrp()
521 	retval = -EPERM;  in tiocspgrp()
525 	put_pid(real_tty->ctrl.pgrp);  in tiocspgrp()
526 	real_tty->ctrl.pgrp = get_pid(pgrp);  in tiocspgrp()
530 	spin_unlock_irq(&real_tty->ctrl.lock);  in tiocspgrp()
535  *	tiocgsid		-	get session id
537  *	@real_tty: tty side of the tty passed by the user if a pty else the tty
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()
553 		return -ENOTTY;  in tiocgsid()
555 	spin_lock_irqsave(&real_tty->ctrl.lock, flags);  in tiocgsid()
556 	if (!real_tty->ctrl.session)  in tiocgsid()
558 	sid = pid_vnr(real_tty->ctrl.session);  in tiocgsid()
559 	spin_unlock_irqrestore(&real_tty->ctrl.lock, flags);  in tiocgsid()
564 	spin_unlock_irqrestore(&real_tty->ctrl.lock, flags);  in tiocgsid()
565 	return -ENOTTY;  in tiocgsid()
569  * Called from tty_ioctl(). If tty is a pty then real_tty is the slave side,
579 		if (current->signal->tty != tty)  in tty_jobctrl_ioctl()
580 			return -ENOTTY;  in tty_jobctrl_ioctl()
592 	return -ENOIOCTLCMD;  in tty_jobctrl_ioctl()