svn commit: r281726 - head/sys/compat/linux

[Edward Tomasz Napierala]

Author: trasz
Date: Sun Apr 19 07:12:16 2015
New Revision: 281726
URL: https://svnweb.freebsd.org/changeset/base/281726

Log:
  Optimize the O_NOCTTY handling hack in linux_common_open().
  
  Differential Revision:	https://reviews.freebsd.org/D2323
  Reviewed by:	kib@
  MFC after:	1 month
  Sponsored by:	The FreeBSD Foundation

Modified:
  head/sys/compat/linux/linux_file.c

Modified: head/sys/compat/linux/linux_file.c
==============================================================================
--- head/sys/compat/linux/linux_file.c	Sun Apr 19 06:18:41 2015	(r281725)
+++ head/sys/compat/linux/linux_file.c	Sun Apr 19 07:12:16 2015	(r281726)
@@ -132,39 +132,38 @@ linux_common_open(struct thread *td, int
     /* XXX LINUX_O_NOATIME: unable to be easily implemented. */
 
     error = kern_openat(td, dirfd, path, UIO_SYSSPACE, bsd_flags, mode);
+    if (error != 0)
+	    goto done;
 
-    if (!error) {
-	    fd = td->td_retval[0];
-	    /*
-	     * XXX In between kern_open() and fget(), another process
-	     * having the same filedesc could use that fd without
-	     * checking below.
-	     */
-	    error = fget(td, fd, cap_rights_init(&rights, CAP_IOCTL), &fp);
-	    if (!error) {
-		    sx_slock(&proctree_lock);
-		    PROC_LOCK(p);
-		    if (!(bsd_flags & O_NOCTTY) &&
-			SESS_LEADER(p) && !(p->p_flag & P_CONTROLT)) {
-			    PROC_UNLOCK(p);
-			    sx_unlock(&proctree_lock);
-			    /* XXXPJD: Verify if TIOCSCTTY is allowed. */
-			    if (fp->f_type == DTYPE_VNODE)
-				    (void) fo_ioctl(fp, TIOCSCTTY, (caddr_t) 0,
-					     td->td_ucred, td);
-		    } else {
-			    PROC_UNLOCK(p);
-			    sx_sunlock(&proctree_lock);
-		    }
+    if (bsd_flags & O_NOCTTY)
+	    goto done;
+
+    /*
+     * XXX In between kern_open() and fget(), another process
+     * having the same filedesc could use that fd without
+     * checking below.
+     */
+    fd = td->td_retval[0];
+    if (fget(td, fd, cap_rights_init(&rights, CAP_IOCTL), &fp) == 0) {
+	    if (fp->f_type != DTYPE_VNODE) {
 		    fdrop(fp, td);
-		    /*
-		     * XXX as above, fdrop()/kern_close() pair is racy.
-		     */
-		    if (error)
-			    kern_close(td, fd);
+		    goto done;
+	    }
+	    sx_slock(&proctree_lock);
+	    PROC_LOCK(p);
+	    if (SESS_LEADER(p) && !(p->p_flag & P_CONTROLT)) {
+		    PROC_UNLOCK(p);
+		    sx_sunlock(&proctree_lock);
+		    /* XXXPJD: Verify if TIOCSCTTY is allowed. */
+		    (void) fo_ioctl(fp, TIOCSCTTY, (caddr_t) 0,
+			td->td_ucred, td);
+	    } else {
+		    PROC_UNLOCK(p);
+		    sx_sunlock(&proctree_lock);
 	    }
     }
 
+done:
 #ifdef DEBUG
     if (ldebug(open))
 	    printf(LMSG("open returns error %d"), error);