283 lines
8.1 KiB
C
283 lines
8.1 KiB
C
/*
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* Copyright (c) 1997-2013 Apple Computer, Inc. All rights reserved.
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*
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* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
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*
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* This file contains Original Code and/or Modifications of Original Code
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* as defined in and that are subject to the Apple Public Source License
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* Version 2.0 (the 'License'). You may not use this file except in
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* compliance with the License. The rights granted to you under the License
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* may not be used to create, or enable the creation or redistribution of,
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* unlawful or unlicensed copies of an Apple operating system, or to
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* circumvent, violate, or enable the circumvention or violation of, any
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* terms of an Apple operating system software license agreement.
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*
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* Please obtain a copy of the License at
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* http://www.opensource.apple.com/apsl/ and read it before using this file.
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*
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* The Original Code and all software distributed under the License are
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* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
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* Please see the License for the specific language governing rights and
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* limitations under the License.
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*
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* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
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*/
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/*-
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* Copyright (c) 1982, 1986, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)tty_tty.c 8.2 (Berkeley) 9/23/93
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*/
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/*
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* Indirect driver for controlling tty.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/ioctl.h>
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#include <sys/proc_internal.h>
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#include <sys/tty.h>
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#include <sys/vnode_internal.h>
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#include <sys/file_internal.h>
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#include <sys/kauth.h>
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/* Forward declarations for cdevsw[] entry */
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/* XXX we should consider making these static */
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int cttyopen(dev_t dev, int flag, int mode, proc_t p);
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int cttyread(dev_t dev, struct uio *uio, int flag);
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int cttywrite(dev_t dev, struct uio *uio, int flag);
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int cttyioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p);
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int cttyselect(dev_t dev, int flag, void* wql, proc_t p);
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static vnode_t cttyvp(proc_t p);
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int
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cttyopen(dev_t dev, int flag, __unused int mode, proc_t p)
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{
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vnode_t ttyvp = cttyvp(p);
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struct vfs_context context;
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int error = 0;
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int cttyflag, doclose = 0;
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struct session *sessp;
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struct pgrp *pg;
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if (ttyvp == NULL) {
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return ENXIO;
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}
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context.vc_thread = current_thread();
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context.vc_ucred = kauth_cred_proc_ref(p);
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pg = proc_pgrp(p, &sessp);
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cttyflag = os_ref_get_raw_mask(&sessp->s_refcount) & S_CTTYREF;
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/*
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* A little hack--this device, used by many processes,
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* happens to do an open on another device, which can
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* cause unhappiness if the second-level open blocks indefinitely
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* (as could be the case if the master side has hung up). Since
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* we know that this driver doesn't care about the serializing
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* opens and closes, we can drop the lock. To avoid opencount leak,
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* open the vnode only for the first time.
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*/
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if (cttyflag == 0) {
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devsw_unlock(dev, S_IFCHR);
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error = VNOP_OPEN(ttyvp, flag, &context);
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devsw_lock(dev, S_IFCHR);
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if (error) {
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goto out;
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}
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/*
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* If S_CTTYREF is set, some other thread did an open
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* and was able to set the flag, now perform a close, else
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* set the flag.
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*/
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if (os_atomic_or_orig(&sessp->s_refcount, S_CTTYREF, relaxed) & S_CTTYREF) {
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doclose = 1;
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}
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/*
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* We have to take a reference here to make sure a close
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* gets called during revoke. Note that once a controlling
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* tty gets opened by this driver, the only way close will
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* get called is when the session leader , whose controlling
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* tty is ttyvp, exits and vnode is revoked. We cannot
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* redirect close from this driver because underlying controlling
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* terminal might change and close may get redirected to a
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* wrong vnode causing panic.
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*/
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if (doclose) {
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devsw_unlock(dev, S_IFCHR);
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VNOP_CLOSE(ttyvp, flag, &context);
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devsw_lock(dev, S_IFCHR);
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} else {
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error = vnode_ref(ttyvp);
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}
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}
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out:
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pgrp_rele(pg);
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vnode_put(ttyvp);
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kauth_cred_unref(&context.vc_ucred);
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return error;
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}
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int
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cttyread(__unused dev_t dev, struct uio *uio, int flag)
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{
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vnode_t ttyvp = cttyvp(current_proc());
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struct vfs_context context;
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int error;
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if (ttyvp == NULL) {
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return EIO;
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}
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context.vc_thread = current_thread();
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context.vc_ucred = NOCRED;
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error = VNOP_READ(ttyvp, uio, flag, &context);
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vnode_put(ttyvp);
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return error;
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}
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int
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cttywrite(__unused dev_t dev, struct uio *uio, int flag)
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{
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vnode_t ttyvp = cttyvp(current_proc());
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struct vfs_context context;
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int error;
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if (ttyvp == NULL) {
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return EIO;
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}
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context.vc_thread = current_thread();
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context.vc_ucred = NOCRED;
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error = VNOP_WRITE(ttyvp, uio, flag, &context);
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vnode_put(ttyvp);
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return error;
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}
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int
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cttyioctl(__unused dev_t dev, u_long cmd, caddr_t addr, int flag, proc_t p)
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{
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vnode_t ttyvp = cttyvp(current_proc());
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struct vfs_context context;
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int error = 0;
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if (ttyvp == NULL) {
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return EIO;
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}
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if (cmd == TIOCSCTTY) { /* don't allow controlling tty to be set */
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error = EINVAL; /* to controlling tty -- infinite recursion */
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goto out;
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}
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if (cmd == TIOCNOTTY) {
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struct pgrp *pg = proc_pgrp(p, NULL);
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if (!SESS_LEADER(p, pg->pg_session)) {
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os_atomic_andnot(&p->p_flag, P_CONTROLT, relaxed);
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error = 0;
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} else {
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error = EINVAL;
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}
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pgrp_rele(pg);
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goto out;
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}
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context.vc_thread = current_thread();
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context.vc_ucred = NOCRED;
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error = VNOP_IOCTL(ttyvp, cmd, addr, flag, &context);
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out:
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vnode_put(ttyvp);
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return error;
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}
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int
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cttyselect(__unused dev_t dev, int flag, void* wql, __unused proc_t p)
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{
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vnode_t ttyvp = cttyvp(current_proc());
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struct vfs_context context;
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int error;
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context.vc_thread = current_thread();
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context.vc_ucred = NOCRED;
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if (ttyvp == NULL) {
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return 1; /* try operation to get EOF/failure */
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}
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error = VNOP_SELECT(ttyvp, flag, FREAD | FWRITE, wql, &context);
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vnode_put(ttyvp);
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return error;
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}
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/* This returns vnode with ioref */
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static vnode_t
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cttyvp(proc_t p)
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{
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struct pgrp *pg;
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struct session *sessp;
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vnode_t vp;
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int vid;
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pg = proc_pgrp(p, &sessp);
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session_lock(sessp);
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vp = (p->p_flag & P_CONTROLT ? sessp->s_ttyvp : NULLVP);
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vid = sessp->s_ttyvid;
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if (vp) {
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vnode_hold(vp);
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}
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session_unlock(sessp);
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pgrp_rele(pg);
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if (vp != NULLVP) {
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/* cannot get an IO reference, return NULLVP */
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if (vnode_getwithvid(vp, vid) != 0) {
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vnode_drop(vp);
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vp = NULLVP;
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} else {
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vnode_drop(vp);
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}
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}
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return vp;
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}
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