diff --git a/lib/libc/gen/directory.3 b/lib/libc/gen/directory.3
index 23cd2f91d20b..6334d384ae21 100644
--- a/lib/libc/gen/directory.3
+++ b/lib/libc/gen/directory.3
@@ -38,6 +38,7 @@
 .Sh NAME
 .Nm opendir ,
 .Nm readdir ,
+.Nm readdir_r ,
 .Nm telldir ,
 .Nm seekdir ,
 .Nm rewinddir ,
@@ -51,6 +52,8 @@
 .Fn opendir "const char *filename"
 .Ft struct dirent *
 .Fn readdir "DIR *dirp"
+.Ft int
+.Fn readdir_r "DIR *dirp" "struct dirent *entry" "struct dirent **result"
 .Ft long
 .Fn telldir "const DIR *dirp"
 .Ft void
@@ -90,6 +93,22 @@ upon reaching the end of the directory or detecting an invalid
 .Fn seekdir
 operation.
 .Pp
+.Fn readdir_r
+provides the same functionality as
+.Fn readdir ,
+but the caller must provide a directory
+.Fa entry
+buffer to store the results in.  If the read succeeds, 
+.Fa result
+is pointed at the
+.Fa entry ;
+upon reaching the end of the directory
+.Fa result
+is set to
+.Dv NULL .
+.Fn readdir_r
+returns 0 on success or an error number to indicate failure.
+.Pp
 The
 .Fn telldir
 function
diff --git a/lib/libc/gen/readdir.c b/lib/libc/gen/readdir.c
index 74246b92b25f..9b8c1758554a 100644
--- a/lib/libc/gen/readdir.c
+++ b/lib/libc/gen/readdir.c
@@ -95,8 +95,9 @@ readdir_r(dirp, entry, result)
 		return EBADF;
 	}
 #ifdef _THREAD_SAFE
-	if ((ret = _FD_LOCK(dirp->dd_fd, FD_READ, NULL)) != 0)
+	if ((ret = _FD_LOCK(dirp->dd_fd, FD_READ, NULL)) != 0) {
 		return ret;
+	}
 #endif
 	errno = 0;
 	dp = readdir(dirp);
@@ -106,14 +107,16 @@ readdir_r(dirp, entry, result)
 #endif
 		return errno;
 	}
-	if (dp != NULL) 
+	if (dp != NULL) {
 		memcpy(entry, dp, sizeof *entry);
+	}
 #ifdef _THREAD_SAFE
 	_FD_UNLOCK(dirp->dd_fd, FD_READ);
 #endif
-	if (dp != NULL)
-	*result = entry;
-	else
+	if (dp != NULL) {
+		*result = entry;
+	} else {
 		*result = NULL;
+	}
 	return 0;
 }