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Date:      Wed, 22 Oct 2014 00:23:44 +0000 (UTC)
From:      Mateusz Guzik <mjg@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r273441 - in head/sys: kern sys
Message-ID:  <201410220023.s9M0NiBX089974@svn.freebsd.org>
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Author: mjg
Date: Wed Oct 22 00:23:43 2014
New Revision: 273441
URL: https://svnweb.freebsd.org/changeset/base/273441

Log:
  filedesc: cleanup setugidsafety a little
  
  Rename it to fdsetugidsafety for consistency with other functions.
  
  There is no need to take filedesc lock if not closing any files.
  
  The loop has to verify each file and we are guaranteed fdtable has space
  for at least 20 fds. As such there is no need to check fd_lastfile.
  
  While here tidy up is_unsafe.

Modified:
  head/sys/kern/kern_descrip.c
  head/sys/kern/kern_exec.c
  head/sys/sys/filedesc.h

Modified: head/sys/kern/kern_descrip.c
==============================================================================
--- head/sys/kern/kern_descrip.c	Tue Oct 21 23:57:31 2014	(r273440)
+++ head/sys/kern/kern_descrip.c	Wed Oct 22 00:23:43 2014	(r273441)
@@ -2078,23 +2078,23 @@ fdescfree(struct thread *td)
  * Since setugidsafety calls this only for fd 0, 1 and 2, this check is
  * sufficient.  We also don't check for setugidness since we know we are.
  */
-static int
+static bool
 is_unsafe(struct file *fp)
 {
-	if (fp->f_type == DTYPE_VNODE) {
-		struct vnode *vp = fp->f_vnode;
+	struct vnode *vp;
 
-		if ((vp->v_vflag & VV_PROCDEP) != 0)
-			return (1);
-	}
-	return (0);
+	if (fp->f_type != DTYPE_VNODE)
+		return (false);
+
+	vp = fp->f_vnode;
+	return ((vp->v_vflag & VV_PROCDEP) != 0);
 }
 
 /*
  * Make this setguid thing safe, if at all possible.
  */
 void
-setugidsafety(struct thread *td)
+fdsetugidsafety(struct thread *td)
 {
 	struct filedesc *fdp;
 	struct file *fp;
@@ -2102,12 +2102,10 @@ setugidsafety(struct thread *td)
 
 	fdp = td->td_proc->p_fd;
 	KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared"));
-	FILEDESC_XLOCK(fdp);
-	for (i = 0; i <= fdp->fd_lastfile; i++) {
-		if (i > 2)
-			break;
+	for (i = 0; i <= 2; i++) {
 		fp = fdp->fd_ofiles[i].fde_file;
 		if (fp != NULL && is_unsafe(fp)) {
+			FILEDESC_XLOCK(fdp);
 			knote_fdclose(td, i);
 			/*
 			 * NULL-out descriptor prior to close to avoid
@@ -2116,10 +2114,8 @@ setugidsafety(struct thread *td)
 			fdfree(fdp, i);
 			FILEDESC_XUNLOCK(fdp);
 			(void) closef(fp, td);
-			FILEDESC_XLOCK(fdp);
 		}
 	}
-	FILEDESC_XUNLOCK(fdp);
 }
 
 /*

Modified: head/sys/kern/kern_exec.c
==============================================================================
--- head/sys/kern/kern_exec.c	Tue Oct 21 23:57:31 2014	(r273440)
+++ head/sys/kern/kern_exec.c	Wed Oct 22 00:23:43 2014	(r273441)
@@ -695,7 +695,7 @@ interpret:
 		 */
 		PROC_UNLOCK(p);
 		VOP_UNLOCK(imgp->vp, 0);
-		setugidsafety(td);
+		fdsetugidsafety(td);
 		error = fdcheckstd(td);
 		if (error != 0)
 			goto done1;

Modified: head/sys/sys/filedesc.h
==============================================================================
--- head/sys/sys/filedesc.h	Tue Oct 21 23:57:31 2014	(r273440)
+++ head/sys/sys/filedesc.h	Wed Oct 22 00:23:43 2014	(r273441)
@@ -148,6 +148,7 @@ int	fdallocn(struct thread *td, int minf
 int	fdcheckstd(struct thread *td);
 void	fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td);
 void	fdcloseexec(struct thread *td);
+void	fdsetugidsafety(struct thread *td);
 struct	filedesc *fdcopy(struct filedesc *fdp);
 void	fdunshare(struct thread *td);
 void	fdescfree(struct thread *td);
@@ -159,7 +160,6 @@ struct filedesc_to_leader *
 int	getvnode(struct filedesc *fdp, int fd, cap_rights_t *rightsp,
 	    struct file **fpp);
 void	mountcheckdirs(struct vnode *olddp, struct vnode *newdp);
-void	setugidsafety(struct thread *td);
 
 /* Return a referenced file from an unlocked descriptor. */
 int	fget_unlocked(struct filedesc *fdp, int fd, cap_rights_t *needrightsp,

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