X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/fe8ab488e9161c46dd9885d58fc52996dc0249ff..d9a64523371fa019c4575bb400cbbc3a50ac9903:/bsd/miscfs/devfs/devfs_tree.c

diff --git a/bsd/miscfs/devfs/devfs_tree.c b/bsd/miscfs/devfs/devfs_tree.c
index 45d529e8d..6358c5c6b 100644
--- a/bsd/miscfs/devfs/devfs_tree.c
+++ b/bsd/miscfs/devfs/devfs_tree.c
@@ -328,7 +328,7 @@ dev_finddir(const char * path,
 	    while (*scan != '/' && *scan)
 		scan++;
 
-	    strlcpy(component, start, scan - start);
+	    strlcpy(component, start, (scan - start) + 1);
 	    if (*scan == '/')
 		scan++;
 
@@ -967,7 +967,7 @@ static int
 dev_dup_entry(devnode_t * parent, devdirent_t * back, devdirent_t * *dnm_pp,
 	      struct devfsmount *dvm)
 {
-	devdirent_t *	entry_p;
+	devdirent_t *	entry_p = NULL;
 	devdirent_t *	newback;
 	devdirent_t *	newfront;
 	int	error;
@@ -978,10 +978,14 @@ dev_dup_entry(devnode_t * parent, devdirent_t * back, devdirent_t * *dnm_pp,
 	 * go get the node made (if we need to)
 	 * use the back one as a prototype
 	 */
-	if ((error = dev_add_entry(back->de_name, parent, type,
-				NULL, dnp,
-				parent?parent->dn_dvm:dvm, &entry_p)) != 0) {
+    error = dev_add_entry(back->de_name, parent, type, NULL, dnp,
+                          parent?parent->dn_dvm:dvm, &entry_p);
+    if (!error && (entry_p == NULL)) {
+        error = ENOMEM; /* Really can't happen, but make static analyzer happy */
+    }
+	if (error != 0) {
 		printf("duplicating %s failed\n",back->de_name);
+        goto out;
 	}
 
 	/*
@@ -1009,6 +1013,7 @@ dev_dup_entry(devnode_t * parent, devdirent_t * back, devdirent_t * *dnm_pp,
 			}
 		}
 	}
+out:
 	*dnm_pp = entry_p;
 	return error;
 }
@@ -1156,7 +1161,16 @@ retry:
 
 		DEVFS_UNLOCK();
 
-	        error = vnode_getwithvid(vn_p, vid);
+		/*
+		 * We want to use the drainok variant of vnode_getwithvid
+		 * because we _don't_ want to get an iocount if the vnode is
+		 * is blocked in vnode_drain as it can cause infinite
+		 * loops in vn_open_auth. While in use vnodes are typically
+		 * only reclaimed on forced unmounts, In use devfs tty vnodes
+		 * can  be quite frequently reclaimed by revoke(2) or by the
+		 * exit of a controlling process.
+		 */
+	        error = vnode_getwithvid_drainok(vn_p, vid);
 
 	        DEVFS_LOCK();
 
@@ -1180,22 +1194,25 @@ retry:
 			 * vnode.  Therefore, ENOENT is a valid result.
 			 */
 			error = ENOENT;
+		} else if (error == ENODEV) {
+			/*
+			 * The Filesystem is getting unmounted.
+			 */
+			error = ENOENT;
 		} else if (error && (nretries < DEV_MAX_VNODE_RETRY)) {
 			/*
 			 * If we got an error from vnode_getwithvid, it means
 			 * we raced with a recycle and lost i.e. we asked for
-			 * an iocount only after vnode_drain had completed on
-			 * the vnode and returned with an error only after
-			 * devfs_reclaim was called on the vnode. While
-			 * devfs_reclaim sets dn_vn to NULL but while we were
-			 * waiting to reacquire DEVFS_LOCK, another vnode might
-			 * have gotten associated with the dnp. In either case,
-			 * we need to retry otherwise we will end up returning
-			 * an ENOENT for this lookup but the next lookup will
-			 * succeed because it creates a new vnode (or a racing
-			 * lookup created a new vnode already).
-			 *
-			 * We cap the number of retries at 8.
+			 * an iocount only after vnode_drain had been entered
+			 * for the vnode and returned with an error only after
+			 * devfs_reclaim was called on the vnode.  devfs_reclaim
+			 * sets dn_vn to NULL but while we were waiting to
+			 * reacquire DEVFS_LOCK, another vnode might have gotten
+			 * associated with the dnp. In either case, we need to
+			 * retry otherwise we will end up returning an ENOENT
+			 * for this lookup but the next lookup will  succeed
+			 * because it creates a new vnode (or a racing  lookup
+			 * created a new vnode already).
 			 */
 			error = 0;
 			nretries++;