[PATCH 6/7] add conversion helpers for invalid mach port names

[Luca Dariz]

* include/mach/port.h: add _NAME_ variants for port NULL and DEAD and
  add helpers to check for invalid  port names
* ipc/port.h: add helpers to properly convert to/from invalid mach
  port names.
---
 include/mach/port.h |  8 ++++++--
 ipc/port.h          | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/include/mach/port.h b/include/mach/port.h
index e38be614..c9bbcf17 100644
--- a/include/mach/port.h
+++ b/include/mach/port.h
@@ -72,9 +72,13 @@ typedef int *rpc_signature_info_t;
 
 #define MACH_PORT_NULL         0 /* works with both user and kernel ports */
 #define MACH_PORT_DEAD         ((mach_port_t) ~0)
+#define MACH_PORT_NAME_NULL    ((mach_port_name_t) 0)
+#define MACH_PORT_NAME_DEAD    ((mach_port_name_t) ~0)
 
-#define        MACH_PORT_VALID(name)   \
-               (((name) != MACH_PORT_NULL) && ((name) != MACH_PORT_DEAD))
+#define        MACH_PORT_VALID(port)   \
+               (((port) != MACH_PORT_NULL) && ((port) != MACH_PORT_DEAD))
+#define        MACH_PORT_NAME_VALID(name)      \
+               (((name) != MACH_PORT_NAME_NULL) && ((name) != 
MACH_PORT_NAME_DEAD))
 
 /*
  *  These are the different rights a task may have.
diff --git a/ipc/port.h b/ipc/port.h
index 9ef586c1..c85685d7 100644
--- a/ipc/port.h
+++ b/ipc/port.h
@@ -39,6 +39,7 @@
 #ifndef        _IPC_PORT_H_
 #define _IPC_PORT_H_
 
+#include <kern/debug.h>
 #include <mach/port.h>
 
 /*
@@ -83,4 +84,23 @@ typedef mach_port_name_t mach_port_gen_t;    /* generation 
numbers */
 #define        MACH_PORT_UREFS_UNDERFLOW(urefs, delta)                         
\
                (((delta) < 0) && (-(delta) > (urefs)))
 
+
+static inline mach_port_t invalid_name_to_port(mach_port_name_t name)
+{
+  if (name == MACH_PORT_NAME_NULL)
+    return MACH_PORT_NULL;
+  if (name == MACH_PORT_NAME_DEAD)
+    return MACH_PORT_DEAD;
+  panic("invalid_name_to_port() called with a valid port");
+}
+
+static inline mach_port_name_t invalid_port_to_name(mach_port_t port)
+{
+  if (port == MACH_PORT_NULL)
+    return MACH_PORT_NAME_NULL;
+  if (port == MACH_PORT_DEAD)
+    return MACH_PORT_NAME_DEAD;
+  panic("invalid_port_to_name() called with a valid name");
+}
+
 #endif /* _IPC_PORT_H_ */
-- 
2.30.2