Mach messages: exc

Message catalog and dispatch · All subsystem ranges · Kernel entry map

osfmk/mach/exc.defs. Listed in the kernel kobject subsystem table, subject to the registration guards and per-slot skips. The destination's typed capability still controls admission. Registration evidence: mig_e.

Reading these entries

IDs are computed from the explicit preprocessing profiles in the catalog guide, counting both routines and skip slots. They are not discovered from a running kernel. Each entry retains all observed names/declaration locations; the displayed fields come from the first non-skipped profile. Alternative declarations can have different fields. simpleroutine is one-way at the MIG interface level.

An interface contract block quotes the adjacent local .defs comment with whitespace normalized. Mechanism paragraphs explain selected implementation decisions. Local body links and call names identify implementation evidence; syntactic call lists are reading aids, not a proof that every listed call executes on every path. Short complete implementation bodies are included where especially useful.

Complete routine and reserved-slot catalog

2401: exception_raise

Deliver a traditional Mach exception with thread/task rights and 32-bit exception-code elements; the receiver chooses its policy.

Mechanism: The sender selects this older narrow-code form for EXCEPTION_DEFAULT without MACH_EXCEPTION_CODES, exporting task/thread ports at the policy-selected flavor. The in-kernel Unix receiver first requires ux_handler_port, widens the two codes and delegates to catch_mach_exception_raise; a different registered exception server may implement its own receiver. See exception delivery. Local path.

Declarations: exception_raise (server64, server32, client64, client32, libsyscall64, sender64, local64).

Fields after preprocessing (server64):

routine exception_raise(
   exception_port : mach_port_t;
   thread : mach_port_t;
   task : mach_port_t;
   exception : exception_type_t;
   code : exception_data_t
   );

Local body: catch_exception_raise. Calls visible in this body include catch_mach_exception_raise.

2402: exception_raise_state

Deliver a traditional exception with thread-state flavor/data and accept replacement state in the reply.

Mechanism: The EXCEPTION_STATE sender obtains architecture state with thread_getstatus_to_user, allocates reply-state storage and sends narrow exception codes with a flavor/count. A successful reply is validated through thread_setstatus_from_user, except for corpse notification. The local Unix receiver for this state-only form returns KERN_INVALID_ARGUMENT; a user exception server supplies the useful receiver. Local path.

Declarations: exception_raise_state (server64, server32, client64, client32, libsyscall64, sender64, local64).

Fields after preprocessing (server64):

routine exception_raise_state(
   exception_port : mach_port_t;
   exception : exception_type_t;
   code : exception_data_t, const;
    inout flavor : int;
   old_state : thread_state_t, const;
      out new_state : thread_state_t
   );

Local body: catch_exception_raise_state.

Implementation excerpt:

catch_exception_raise_state(
	__unused mach_port_t                 exception_port,
	__unused exception_type_t            exception,
	__unused const exception_data_t      code,
	__unused mach_msg_type_number_t      codeCnt,
	__unused int                        *flavor,
	__unused const thread_state_t        old_state,
	__unused mach_msg_type_number_t      old_stateCnt,
	__unused thread_state_t              new_state,
	__unused mach_msg_type_number_t     *new_stateCnt)
{
	return KERN_INVALID_ARGUMENT;
}

2403: exception_raise_state_identity

Deliver a traditional exception with both thread/task identity rights and state; accept replacement state in the reply.

Mechanism: The state-and-identity sender exports policy-selected task/thread capabilities as well as old thread state, flavor and narrow codes. A successful reply is imported through architecture/state validation only when the exception is not EXC_CORPSE_NOTIFY and the exported thread port is IKOT_THREAD_CONTROL; the read-port delivery branch does not import returned state. The in-kernel Unix handler is an invalid-argument stub for this behavior; its presence in the generated exception subsystem does not mean it implements state editing. Local path.

Declarations: exception_raise_state_identity (server64, server32, client64, client32, libsyscall64, sender64, local64).

Fields after preprocessing (server64):

routine exception_raise_state_identity(
   exception_port : mach_port_t;
   thread : mach_port_t;
   task : mach_port_t;
   exception : exception_type_t;
   code : exception_data_t;
    inout flavor : int;
   old_state : thread_state_t;
      out new_state : thread_state_t
   );

Local body: catch_exception_raise_state_identity.

Implementation excerpt:

catch_exception_raise_state_identity(
	__unused mach_port_t                exception_port,
	__unused mach_port_t                thread,
	__unused mach_port_t                task,
	__unused exception_type_t           exception,
	__unused exception_data_t           code,
	__unused mach_msg_type_number_t     codeCnt,
	__unused int                       *flavor,
	__unused thread_state_t             old_state,
	__unused mach_msg_type_number_t     old_stateCnt,
	__unused thread_state_t             new_state,
	__unused mach_msg_type_number_t    *new_stateCnt)
{
	return KERN_INVALID_ARGUMENT;
}