/*
- * Copyright (c) 1997-2006 Apple Computer, Inc. All rights reserved.
+ * 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
* 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,
* 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@
*/
/*-
int cttyselect(dev_t dev, int flag, void* wql, proc_t p);
static vnode_t cttyvp(proc_t p);
-
int
-cttyopen(__unused dev_t dev, int flag, __unused int mode, proc_t p)
+cttyopen(dev_t dev, int flag, __unused int mode, proc_t p)
{
vnode_t ttyvp = cttyvp(p);
struct vfs_context context;
- int error;
+ int error = 0;
+ int cttyflag, doclose = 0;
+ struct session *sessp;
- if (ttyvp == NULL)
- return (ENXIO);
+ if (ttyvp == NULL) {
+ return ENXIO;
+ }
context.vc_thread = current_thread();
context.vc_ucred = kauth_cred_proc_ref(p);
- error = VNOP_OPEN(ttyvp, flag, &context);
+ 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);
+ return error;
}
int
struct vfs_context context;
int error;
- if (ttyvp == NULL)
- return (EIO);
+ 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);
+ return error;
}
int
struct vfs_context context;
int error;
- if (ttyvp == NULL)
- return (EIO);
+ 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);
+ return error;
}
int
struct session *sessp;
int error = 0;
- if (ttyvp == NULL)
- return (EIO);
- if (cmd == TIOCSCTTY) { /* don't allow controlling tty to be set */
+ 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;
}
sessp = proc_session(p);
if (!SESS_LEADER(p, sessp)) {
OSBitAndAtomic(~((uint32_t)P_CONTROLT), &p->p_flag);
- if (sessp != SESSION_NULL)
+ if (sessp != SESSION_NULL) {
session_rele(sessp);
+ }
error = 0;
goto out;
} else {
- if (sessp != SESSION_NULL)
+ if (sessp != SESSION_NULL) {
session_rele(sessp);
+ }
error = EINVAL;
goto out;
}
error = VNOP_IOCTL(ttyvp, cmd, addr, flag, &context);
out:
vnode_put(ttyvp);
- return (error);
+ return error;
}
int
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);
+ 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);
+ return error;
}
/* This returns vnode with ioref */
session_lock(sessp);
vp = (p->p_flag & P_CONTROLT ? sessp->s_ttyvp : NULLVP);
- vid = sessp->s_ttyvid;
+ 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)
+ if (vnode_getwithvid(vp, vid) != 0) {
vp = NULLVP;
+ }
}
- return(vp);
+ return vp;
}
-
projects / apple / xnu.git / blobdiff