[apple/xnu.git] / bsd / kern / tty_tty.c

/*
 * Copyright (c) 1997-2013 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*-
 * Copyright (c) 1982, 1986, 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)tty_tty.c	8.2 (Berkeley) 9/23/93
 */

/*
 * Indirect driver for controlling tty.
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/ioctl.h>
#include <sys/proc_internal.h>
#include <sys/tty.h>
#include <sys/vnode_internal.h>
#include <sys/file_internal.h>
#include <sys/kauth.h>

/* Forward declarations for cdevsw[] entry */
/* XXX we should consider making these static */
int cttyopen(dev_t dev, int flag, int mode, proc_t p);
int cttyread(dev_t dev, struct uio *uio, int flag);
int cttywrite(dev_t dev, struct uio *uio, int flag);
int cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p);
int cttyselect(dev_t dev, int flag, void* wql, proc_t p);
static vnode_t cttyvp(proc_t p);

int
cttyopen(dev_t dev, int flag, __unused int mode, proc_t p)
{
	vnode_t ttyvp = cttyvp(p);
	struct vfs_context context;
	int error = 0;
	int cttyflag, doclose = 0;
	struct session *sessp;

	if (ttyvp == NULL)
		return (ENXIO);

	context.vc_thread = current_thread();
	context.vc_ucred = kauth_cred_proc_ref(p);

	sessp = proc_session(p);
	session_lock(sessp);
	cttyflag = sessp->s_flags & S_CTTYREF;	
	session_unlock(sessp);

	/*
	 * A little hack--this device, used by many processes,
	 * happens to do an open on another device, which can 
	 * cause unhappiness if the second-level open blocks indefinitely 
	 * (as could be the case if the master side has hung up).  Since
	 * we know that this driver doesn't care about the serializing
	 * opens and closes, we can drop the lock. To avoid opencount leak,
	 * open the vnode only for the first time. 
	 */
	if (cttyflag == 0) {
		devsw_unlock(dev, S_IFCHR);
		error = VNOP_OPEN(ttyvp, flag, &context);
		devsw_lock(dev, S_IFCHR);

		if (error) 
			goto out;
	
		/*
		 * If S_CTTYREF is set, some other thread did an open
		 * and was able to set the flag, now perform a close, else
		 * set the flag.
		 */
		session_lock(sessp);
		if (cttyflag == (sessp->s_flags & S_CTTYREF))
			sessp->s_flags |= S_CTTYREF;
		else
			doclose = 1;
		session_unlock(sessp);

		/*
		 * We have to take a reference here to make sure a close
		 * gets called during revoke. Note that once a controlling 
		 * tty gets opened by this driver, the only way close will
		 * get called is when the session leader , whose controlling
		 * tty is ttyvp, exits and vnode is revoked. We cannot 
		 * redirect close from this driver because underlying controlling
		 * terminal might change and close may get redirected to a 
		 * wrong vnode causing panic.
		 */
		if (doclose) {
			devsw_unlock(dev, S_IFCHR);
			VNOP_CLOSE(ttyvp, flag, &context);
			devsw_lock(dev, S_IFCHR);
		} else {
			error = vnode_ref(ttyvp);
		}
	}
out:
	session_rele(sessp);

	vnode_put(ttyvp);
	kauth_cred_unref(&context.vc_ucred);

	return (error);
}

int
cttyread(__unused dev_t dev, struct uio *uio, int flag)
{
	vnode_t ttyvp = cttyvp(current_proc());
	struct vfs_context context;
	int error;

	if (ttyvp == NULL)
		return (EIO);

	context.vc_thread = current_thread();
	context.vc_ucred = NOCRED;

	error = VNOP_READ(ttyvp, uio, flag, &context);
	vnode_put(ttyvp);

	return (error);
}

int
cttywrite(__unused dev_t dev, struct uio *uio, int flag)
{
	vnode_t ttyvp = cttyvp(current_proc());
	struct vfs_context context;
	int error;

	if (ttyvp == NULL)
		return (EIO);

	context.vc_thread = current_thread();
	context.vc_ucred = NOCRED;

	error = VNOP_WRITE(ttyvp, uio, flag, &context);
	vnode_put(ttyvp);

	return (error);
}

int
cttyioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p)
{
	vnode_t ttyvp = cttyvp(current_proc());
	struct vfs_context context;
	struct session *sessp;
	int error = 0;

	if (ttyvp == NULL)
		return (EIO);
	if (cmd == TIOCSCTTY)  { /* don't allow controlling tty to be set    */
		error = EINVAL; /* to controlling tty -- infinite recursion */
		goto out;
	}
	if (cmd == TIOCNOTTY) {
		sessp = proc_session(p);
		if (!SESS_LEADER(p, sessp)) {
			OSBitAndAtomic(~((uint32_t)P_CONTROLT), &p->p_flag);
			if (sessp != SESSION_NULL)
				session_rele(sessp);
			error = 0;
			goto out;
		} else {
			if (sessp != SESSION_NULL)
				session_rele(sessp);
			error = EINVAL;
			goto out;
		}
	}
	context.vc_thread = current_thread();
	context.vc_ucred = NOCRED;

	error = VNOP_IOCTL(ttyvp, cmd, addr, flag, &context);
out:
	vnode_put(ttyvp);
	return (error);
}

int
cttyselect(__unused dev_t dev, int flag, void* wql, __unused proc_t p)
{
	vnode_t ttyvp = cttyvp(current_proc());
	struct vfs_context context;
	int error;

	context.vc_thread = current_thread();
	context.vc_ucred = NOCRED;

	if (ttyvp == NULL)
		return (1);	/* try operation to get EOF/failure */
	error = VNOP_SELECT(ttyvp, flag, FREAD|FWRITE, wql, &context);
	vnode_put(ttyvp);
	return (error);
}

/* This returns vnode with ioref */
static vnode_t
cttyvp(proc_t p)
{
	vnode_t vp;
	int vid;
	struct session *sessp;

	sessp = proc_session(p);

	session_lock(sessp);
	vp = (p->p_flag & P_CONTROLT ? sessp->s_ttyvp : NULLVP);
	vid = sessp->s_ttyvid;	
	session_unlock(sessp);

	session_rele(sessp);

	if (vp != NULLVP) {
		/* cannot get an IO reference, return NULLVP */
		if (vnode_getwithvid(vp, vid) != 0)
			vp = NULLVP;
	}
	return(vp);
}
Commit	Line	Data
1c79356b	1	/*
39236c6e	2	* Copyright (c) 1997-2013 Apple Computer, Inc. All rights reserved.
5d5c5d0d	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
2d21ac55 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
8f6c56a5	14	*
2d21ac55 A	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
8f6c56a5	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b	27	*/
1c79356b A	28	/*-
	29	* Copyright (c) 1982, 1986, 1991, 1993
	30	* The Regents of the University of California. All rights reserved.
	31	*
	32	* Redistribution and use in source and binary forms, with or without
	33	* modification, are permitted provided that the following conditions
	34	* are met:
	35	* 1. Redistributions of source code must retain the above copyright
	36	* notice, this list of conditions and the following disclaimer.
	37	* 2. Redistributions in binary form must reproduce the above copyright
	38	* notice, this list of conditions and the following disclaimer in the
	39	* documentation and/or other materials provided with the distribution.
	40	* 3. All advertising materials mentioning features or use of this software
	41	* must display the following acknowledgement:
	42	* This product includes software developed by the University of
	43	* California, Berkeley and its contributors.
	44	* 4. Neither the name of the University nor the names of its contributors
	45	* may be used to endorse or promote products derived from this software
	46	* without specific prior written permission.
	47	*
	48	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	49	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	50	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	51	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	52	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	53	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	54	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	55	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	56	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	57	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	58	* SUCH DAMAGE.
	59	*
	60	* @(#)tty_tty.c 8.2 (Berkeley) 9/23/93
	61	*/
	62
	63	/*
	64	* Indirect driver for controlling tty.
	65	*/
	66	#include <sys/param.h>
	67	#include <sys/systm.h>
	68	#include <sys/conf.h>
	69	#include <sys/ioctl.h>
91447636	70	#include <sys/proc_internal.h>
1c79356b	71	#include <sys/tty.h>
91447636 A	72	#include <sys/vnode_internal.h>
91447636 A	73	#include <sys/file_internal.h>
2d21ac55	74	#include <sys/kauth.h>
91447636 A	75
	76	/* Forward declarations for cdevsw[] entry */
	77	/* XXX we should consider making these static */
2d21ac55	78	int cttyopen(dev_t dev, int flag, int mode, proc_t p);
91447636 A	79	int cttyread(dev_t dev, struct uio *uio, int flag);
91447636 A	80	int cttywrite(dev_t dev, struct uio *uio, int flag);
2d21ac55 A	81	int cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p);
	82	int cttyselect(dev_t dev, int flag, void* wql, proc_t p);
	83	static vnode_t cttyvp(proc_t p);
1c79356b	84
1c79356b	85	int
6d2010ae	86	cttyopen(dev_t dev, int flag, __unused int mode, proc_t p)
1c79356b	87	{
39236c6e A	88	vnode_t ttyvp = cttyvp(p);
	89	struct vfs_context context;
	90	int error = 0;
	91	int cttyflag, doclose = 0;
	92	struct session *sessp;
1c79356b	93
39236c6e A	94	if (ttyvp == NULL)
39236c6e A	95	return (ENXIO);
316670eb	96
39236c6e A	97	context.vc_thread = current_thread();
39236c6e A	98	context.vc_ucred = kauth_cred_proc_ref(p);
316670eb	99
39236c6e A	100	sessp = proc_session(p);
	101	session_lock(sessp);
	102	cttyflag = sessp->s_flags & S_CTTYREF;
	103	session_unlock(sessp);
316670eb	104
39236c6e A	105	/*
	106	* A little hack--this device, used by many processes,
	107	* happens to do an open on another device, which can
	108	* cause unhappiness if the second-level open blocks indefinitely
	109	* (as could be the case if the master side has hung up). Since
	110	* we know that this driver doesn't care about the serializing
	111	* opens and closes, we can drop the lock. To avoid opencount leak,
	112	* open the vnode only for the first time.
	113	*/
	114	if (cttyflag == 0) {
	115	devsw_unlock(dev, S_IFCHR);
316670eb	116	error = VNOP_OPEN(ttyvp, flag, &context);
39236c6e A	117	devsw_lock(dev, S_IFCHR);
	118
	119	if (error)
	120	goto out;
	121
	122	/*
	123	* If S_CTTYREF is set, some other thread did an open
	124	* and was able to set the flag, now perform a close, else
	125	* set the flag.
	126	*/
	127	session_lock(sessp);
	128	if (cttyflag == (sessp->s_flags & S_CTTYREF))
	129	sessp->s_flags \|= S_CTTYREF;
	130	else
	131	doclose = 1;
	132	session_unlock(sessp);
	133
	134	/*
	135	* We have to take a reference here to make sure a close
	136	* gets called during revoke. Note that once a controlling
	137	* tty gets opened by this driver, the only way close will
	138	* get called is when the session leader , whose controlling
	139	* tty is ttyvp, exits and vnode is revoked. We cannot
	140	* redirect close from this driver because underlying controlling
	141	* terminal might change and close may get redirected to a
	142	* wrong vnode causing panic.
	143	*/
	144	if (doclose) {
	145	devsw_unlock(dev, S_IFCHR);
	146	VNOP_CLOSE(ttyvp, flag, &context);
	147	devsw_lock(dev, S_IFCHR);
	148	} else {
	149	error = vnode_ref(ttyvp);
	150	}
316670eb	151	}
39236c6e A	152	out:
39236c6e A	153	session_rele(sessp);
316670eb	154
39236c6e A	155	vnode_put(ttyvp);
39236c6e A	156	kauth_cred_unref(&context.vc_ucred);
316670eb	157
1c79356b A	158	return (error);
	159	}
	160
1c79356b	161	int
91447636	162	cttyread(__unused dev_t dev, struct uio *uio, int flag)
1c79356b	163	{
2d21ac55	164	vnode_t ttyvp = cttyvp(current_proc());
91447636	165	struct vfs_context context;
1c79356b A	166	int error;
	167
	168	if (ttyvp == NULL)
	169	return (EIO);
91447636	170
2d21ac55	171	context.vc_thread = current_thread();
91447636 A	172	context.vc_ucred = NOCRED;
	173
	174	error = VNOP_READ(ttyvp, uio, flag, &context);
2d21ac55	175	vnode_put(ttyvp);
91447636	176
1c79356b A	177	return (error);
	178	}
	179
1c79356b	180	int
91447636	181	cttywrite(__unused dev_t dev, struct uio *uio, int flag)
1c79356b	182	{
2d21ac55	183	vnode_t ttyvp = cttyvp(current_proc());
91447636	184	struct vfs_context context;
1c79356b A	185	int error;
	186
	187	if (ttyvp == NULL)
	188	return (EIO);
91447636	189
2d21ac55	190	context.vc_thread = current_thread();
91447636 A	191	context.vc_ucred = NOCRED;
	192
	193	error = VNOP_WRITE(ttyvp, uio, flag, &context);
2d21ac55	194	vnode_put(ttyvp);
91447636	195
1c79356b A	196	return (error);
	197	}
	198
1c79356b	199	int
2d21ac55	200	cttyioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p)
1c79356b	201	{
2d21ac55	202	vnode_t ttyvp = cttyvp(current_proc());
91447636	203	struct vfs_context context;
2d21ac55 A	204	struct session *sessp;
2d21ac55 A	205	int error = 0;
1c79356b A	206
	207	if (ttyvp == NULL)
	208	return (EIO);
2d21ac55 A	209	if (cmd == TIOCSCTTY) { /* don't allow controlling tty to be set */
	210	error = EINVAL; /* to controlling tty -- infinite recursion */
	211	goto out;
	212	}
1c79356b	213	if (cmd == TIOCNOTTY) {
2d21ac55 A	214	sessp = proc_session(p);
2d21ac55 A	215	if (!SESS_LEADER(p, sessp)) {
b0d623f7	216	OSBitAndAtomic(~((uint32_t)P_CONTROLT), &p->p_flag);
2d21ac55 A	217	if (sessp != SESSION_NULL)
	218	session_rele(sessp);
	219	error = 0;
	220	goto out;
	221	} else {
	222	if (sessp != SESSION_NULL)
	223	session_rele(sessp);
	224	error = EINVAL;
	225	goto out;
	226	}
1c79356b	227	}
2d21ac55	228	context.vc_thread = current_thread();
91447636 A	229	context.vc_ucred = NOCRED;
91447636 A	230
2d21ac55 A	231	error = VNOP_IOCTL(ttyvp, cmd, addr, flag, &context);
	232	out:
	233	vnode_put(ttyvp);
	234	return (error);
1c79356b A	235	}
1c79356b A	236
1c79356b	237	int
2d21ac55	238	cttyselect(__unused dev_t dev, int flag, void* wql, __unused proc_t p)
1c79356b	239	{
2d21ac55	240	vnode_t ttyvp = cttyvp(current_proc());
91447636	241	struct vfs_context context;
2d21ac55	242	int error;
91447636	243
2d21ac55	244	context.vc_thread = current_thread();
91447636	245	context.vc_ucred = NOCRED;
1c79356b A	246
	247	if (ttyvp == NULL)
	248	return (1); /* try operation to get EOF/failure */
2d21ac55 A	249	error = VNOP_SELECT(ttyvp, flag, FREAD\|FWRITE, wql, &context);
	250	vnode_put(ttyvp);
	251	return (error);
1c79356b A	252	}
1c79356b A	253
2d21ac55 A	254	/* This returns vnode with ioref */
	255	static vnode_t
	256	cttyvp(proc_t p)
1c79356b	257	{
2d21ac55 A	258	vnode_t vp;
	259	int vid;
	260	struct session *sessp;
1c79356b	261
2d21ac55	262	sessp = proc_session(p);
1c79356b	263
2d21ac55 A	264	session_lock(sessp);
	265	vp = (p->p_flag & P_CONTROLT ? sessp->s_ttyvp : NULLVP);
	266	vid = sessp->s_ttyvid;
	267	session_unlock(sessp);
	268
	269	session_rele(sessp);
	270
	271	if (vp != NULLVP) {
	272	/* cannot get an IO reference, return NULLVP */
	273	if (vnode_getwithvid(vp, vid) != 0)
	274	vp = NULLVP;
	275	}
	276	return(vp);
	277	}
1c79356b	278