Add new function fdunshare() which encapsulates the necessary light magic

for ensuring that a process' filedesc is not shared with anybody.

Use it in the two places which previously had private implmentations.

This collects all fd_refcnt handling in kern_descrip.c

3 files changed, 22 insertions, 22 deletions

diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index 50902f0..754a3cb 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -1415,6 +1415,25 @@ fdshare(struct filedesc *fdp)
 }
 
 /*
+ * Unshare a filedesc structure, if necessary by making a copy
+ */
+void
+fdunshare(struct proc *p, struct thread *td)
+{
+
+	FILEDESC_LOCK_FAST(p->p_fd);
+	if (p->p_fd->fd_refcnt > 1) {
+		struct filedesc *tmp;
+
+		FILEDESC_UNLOCK_FAST(p->p_fd);
+		tmp = fdcopy(p->p_fd);
+		fdfree(td);
+		p->p_fd = tmp;
+	} else
+		FILEDESC_UNLOCK_FAST(p->p_fd);
+}
+
+/*
  * Copy a filedesc structure.
  * A NULL pointer in returns a NULL reference, this is to ease callers,
  * not catch errors.
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index e21cb00..40e0f0a 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -465,16 +465,7 @@ interpret:
 	 * For security and other reasons, the file descriptor table cannot
 	 * be shared after an exec.
 	 */
-	FILEDESC_LOCK_FAST(p->p_fd);
-	if (p->p_fd->fd_refcnt > 1) {
-		struct filedesc *tmp;
-
-		FILEDESC_UNLOCK_FAST(p->p_fd);
-		tmp = fdcopy(p->p_fd);
-		fdfree(td);
-		p->p_fd = tmp;
-	} else
-		FILEDESC_UNLOCK_FAST(p->p_fd);
+	fdunshare(p, td);
 
 	/*
 	 * Malloc things before we need locks.
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index ae8cce3..3178c10 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -233,18 +233,8 @@ fork1(td, flags, pages, procp)
 		/*
 		 * Unshare file descriptors (from parent).
 		 */
-		if (flags & RFFDG) {
-			FILEDESC_LOCK_FAST(p1->p_fd);
-			if (p1->p_fd->fd_refcnt > 1) {
-				struct filedesc *newfd;
-
-				FILEDESC_UNLOCK_FAST(p1->p_fd);
-				newfd = fdcopy(p1->p_fd);
-				fdfree(td);
-				p1->p_fd = newfd;
-			} else
-				FILEDESC_UNLOCK_FAST(p1->p_fd);
-		}
+		if (flags & RFFDG) 
+			fdunshare(p1, td);
 		*procp = NULL;
 		return (0);
 	}