xnu-792.6.76.tar.gz

[apple/xnu.git] / osfmk / mach / port.h

diff --git a/osfmk/mach/port.h b/osfmk/mach/port.h
index 670924537750ac7973d6fe149db2a773e872413f..b54438dc3932498ef57443745243b4917ed5b7c4 100644 (file)
--- a/osfmk/mach/port.h
+++ b/osfmk/mach/port.h
@@ -1,24 +1,21 @@
 /*
 /*

- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.

  *
  * @APPLE_LICENSE_HEADER_START@
  * 
  *
  * @APPLE_LICENSE_HEADER_START@
  * 

- * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.

  * 
  * 

- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- * 
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER

  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,

- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.

  * 
  * @APPLE_LICENSE_HEADER_END@
  */
  * 
  * @APPLE_LICENSE_HEADER_END@
  */


@@ -55,10 +52,23 @@
 /*
  *     File:   mach/port.h
  *
 /*
  *     File:   mach/port.h
  *

- *     Definition of a port
+ *     Definition of a Mach port
+ *
+ *     Mach ports are the endpoints to Mach-implemented communications
+ *     channels (usually uni-directional message queues, but other types
+ *     also exist).
+ *
+ *     Unique collections of these endpoints are maintained for each
+ *     Mach task.  Each Mach port in the task's collection is given a 
+ *     [task-local] name to identify it - and the the various "rights"
+ *     held by the task for that specific endpoint.
+ *
+ *     This header defines the types used to identify these Mach ports
+ *     and the various rights associated with them.  For more info see:
+ *
+ *     <mach/mach_port.h> - manipulation of port rights in a given space
+ *     <mach/message.h> - message queue [and port right passing] mechanism

  *
  *

- *     [The basic port_t type should probably be machine-dependent,
- *     as it must be represented by a 32-bit integer.]

  */
 
 #ifndef        _MACH_PORT_H_
  */
 
 #ifndef        _MACH_PORT_H_


@@ -68,82 +78,97 @@
 #include <mach/boolean.h>
 #include <mach/machine/vm_types.h>
 
 #include <mach/boolean.h>
 #include <mach/machine/vm_types.h>
 

-#include <sys/appleapiopts.h>
-

 /*
 /*

- * A port_name_t is a 32 bit value which represents a name of a
- * port right within some ipc space.  This is a constant definition
- * everywhere.
+ *     mach_port_name_t - the local identity for a Mach port

  *
  *

- * The type port_t represents a reference added or deleted to a
- * port right.
+ *     The name is Mach port namespace specific.  It is used to
+ *     identify the rights held for that port by the task whose
+ *     namespace is implied [or specifically provided].

  *
  *

- *     At user space, this is represented by returning the name of
- *     the right(s) that got altered within the user's ipc space.
- *     So a port_t is the same type as a port_name_t there.
+ *     Use of this type usually implies just a name - no rights.
+ *     See mach_port_t for a type that implies a "named right."

  *
  *

- *     Since there is no right space for the kernel proper (all rights
- *     are naked rights) these rights are represented by passing a
- *     pointer to the specific ipc_object_t subclass (typically
- *     ipc_port_t) that got altered/is to be altered.
- *
- *     JMM - Because of this pointer/integer overloading, port names
- *     should be defined as uintptr_t types.  But that would make
- *     message headers and descriptors pointer-length dependent.

  */
  */

-typedef natural_t port_name_t;
-typedef port_name_t *port_name_array_t;
+ 
+typedef natural_t mach_port_name_t;
+typedef mach_port_name_t *mach_port_name_array_t;
+
+#ifdef KERNEL_PRIVATE

 
 

-#ifdef KERNEL_PRIVATE
+/* 
+ *     mach_port_t - a named port right
+ *
+ *     In the kernel, "rights" are represented [named] by pointers to
+ *     the ipc port object in question. There is no port namespace for the
+ *     rights to be collected.
+ *
+ *     Actually, there is namespace for the kernel task.  But most kernel
+ *     code - including, but not limited to, Mach IPC code - lives in the
+ *     limbo between the current user-level task and the "next" task. Very
+ *     little of the kernel code runs in full kernel task context.  So very
+ *     little of it gets to use the kernel task's port name space.  
+ *
+ *     Because of this implementation approach, all in-kernel rights for
+ *     a given port coalesce [have the same name/pointer].  The actual
+ *     references are counted in the port itself.  It is up to the kernel
+ *     code in question to "just remember" how many [and what type of]
+ *     rights it holds and handle them appropriately.
+ *
+ */

 
 

-#if !defined(__APPLE_API_PRIVATE) || !defined(MACH_KERNEL_PRIVATE)
+#ifndef        MACH_KERNEL_PRIVATE

 /*
 /*

- * For kernel code that resides outside of mach
- * we define empty structs so that everything will
- * remain strongly typed, without giving out
- * implementation details.
+ *     For kernel code that resides outside of Mach proper, we opaque the
+ *     port structure definition.

  */
 struct ipc_port ;
 
  */
 struct ipc_port ;
 

-#endif /* !__APPLE_API_PRIVATE || !MACH_KERNEL_PRIVATE */
+#endif /* MACH_KERNEL_PRIVATE */

 
 typedef struct ipc_port                *ipc_port_t;
 
 typedef struct ipc_port                *ipc_port_t;

-typedef ipc_port_t             port_t;

 
 

-#define        IPC_PORT_NULL           ((ipc_port_t) 0)
-#define        IPC_PORT_DEAD           ((ipc_port_t)~0)
-#define IPC_PORT_VALID(port)   (((port) != IPC_PORT_NULL) && \
-                                ((port) != IPC_PORT_DEAD))
+#define IPC_PORT_NULL          ((ipc_port_t) 0)
+#define IPC_PORT_DEAD          ((ipc_port_t)~0)
+#define IPC_PORT_VALID(port) \
+       ((port) != IPC_PORT_NULL && (port) != IPC_PORT_DEAD)
+
+typedef ipc_port_t             mach_port_t;
+
+#else  /* KERNEL_PRIVATE */
+
+/* 
+ *     mach_port_t - a named port right
+ *
+ *     In user-space, "rights" are represented by the name of the
+ *     right in the Mach port namespace.  Even so, this type is
+ *     presented as a unique one to more clearly denote the presence
+ *     of a right coming along with the name. 
+ *
+ *     Often, various rights for a port held in a single name space
+ *     will coalesce and are, therefore, be identified by a single name
+ *     [this is the case for send and receive rights].  But not
+ *     always [send-once rights currently get a unique name for
+ *     each right].      
+ *
+ */

 
 

-#else  /* ! KERNEL_PRIVATE */
+#ifndef _MACH_PORT_T
+#define _MACH_PORT_T
+typedef mach_port_name_t               mach_port_t;
+#endif

 
 

-typedef port_name_t            port_t;
+#endif /* KERNEL_PRIVATE */

 
 

-#endif /* KERNEL_PRIVATE */
+typedef mach_port_t                    *mach_port_array_t;

 
 /*
 
 /*

- *  PORT_NULL is a legal value that can be carried in messages.
+ *  MACH_PORT_NULL is a legal value that can be carried in messages.

  *  It indicates the absence of any port or port rights.  (A port
  *  argument keeps the message from being "simple", even if the
  *  It indicates the absence of any port or port rights.  (A port
  *  argument keeps the message from being "simple", even if the

- *  value is PORT_NULL.)  The value PORT_DEAD is also a legal
+ *  value is MACH_PORT_NULL.)  The value MACH_PORT_DEAD is also a legal

  *  value that can be carried in messages.  It indicates
  *  that a port right was present, but it died.
  */
  *  value that can be carried in messages.  It indicates
  *  that a port right was present, but it died.
  */

-#define PORT_NULL              ((port_t) 0)
-#define PORT_DEAD              ((port_t) ~0)
-#define        PORT_VALID(name)                                \
-               (((port_t)(name) != PORT_NULL) &&       \
-                 ((port_t)(name) != PORT_DEAD))
-
-/*
- *  Mach 3.0 renamed everything to have mach_ in front of it.
- *  Do that mapping here, so we have the types and macros in
- *  both formats.
- */
-typedef port_t                 mach_port_t;
-typedef port_t                 *mach_port_array_t;
-typedef port_name_t            mach_port_name_t;
-typedef mach_port_name_t       *mach_port_name_array_t;

 
 #define MACH_PORT_NULL         0  /* intentional loose typing */
 #define MACH_PORT_DEAD         ((mach_port_name_t) ~0)
 
 #define MACH_PORT_NULL         0  /* intentional loose typing */
 #define MACH_PORT_DEAD         ((mach_port_name_t) ~0)


@@ -151,35 +176,39 @@ typedef mach_port_name_t  *mach_port_name_array_t;
                (((name) != MACH_PORT_NULL) &&          \
                 ((name) != MACH_PORT_DEAD))
 
                (((name) != MACH_PORT_NULL) &&          \
                 ((name) != MACH_PORT_DEAD))
 

+

 /*
 /*

- *  mach_port_name_t must be an unsigned type.  Port values
- *  have two parts, a generation number and an index.
- *  These macros encapsulate all knowledge of how
- *  a mach_port_name_t is laid out.  They are made visible 
- *  to user tasks so that packages to map from a mach_port_name_t
- *  to associated user data can discount the generation
- *  nuber (if desired) in doing the mapping.
+ *     For kernel-selected [assigned] port names, the name is
+ *     comprised of two parts: a generation number and an index.
+ *     This approach keeps the exact same name from being generated
+ *     and reused too quickly [to catch right/reference counting bugs].
+ *     The dividing line between the constituent parts is exposed so
+ *     that efficient "mach_port_name_t to data structure pointer"
+ *     conversion implementation can be made.  But it is possible
+ *     for user-level code to assign their own names to Mach ports.
+ *     These are not required to participate in this algorithm.  So
+ *     care should be taken before "assuming" this model.

  *
  *

- *  Within the kernel, ipc/ipc_entry.c implicitly assumes
- *  when it uses the splay tree functions that the generation
- *  number is in the low bits, so that names are ordered first
- *  by index and then by generation.  If the size of generation
- *  numbers changes, be sure to update IE_BITS_GEN_MASK and
- *  friends in ipc/ipc_entry.h.

  */
  */

-#ifndef NO_PORT_GEN
+
+#ifndef        NO_PORT_GEN
+

 #define        MACH_PORT_INDEX(name)           ((name) >> 8)
 #define        MACH_PORT_GEN(name)             (((name) & 0xff) << 24)
 #define        MACH_PORT_MAKE(index, gen)      \
                (((index) << 8) | (gen) >> 24)
 #define        MACH_PORT_INDEX(name)           ((name) >> 8)
 #define        MACH_PORT_GEN(name)             (((name) & 0xff) << 24)
 #define        MACH_PORT_MAKE(index, gen)      \
                (((index) << 8) | (gen) >> 24)

-#else
+
+#else  /* NO_PORT_GEN */
+

 #define        MACH_PORT_INDEX(name)           (name)
 #define        MACH_PORT_GEN(name)             (0)
 #define        MACH_PORT_MAKE(index, gen)      (index)
 #define        MACH_PORT_INDEX(name)           (name)
 #define        MACH_PORT_GEN(name)             (0)
 #define        MACH_PORT_MAKE(index, gen)      (index)

-#endif /* !NO_PORT_GEN */
+
+#endif /* NO_PORT_GEN */
+

 
 /*
 
 /*

- *  These are the different rights a task may have.
+ *  These are the different rights a task may have for a port.

  *  The MACH_PORT_RIGHT_* definitions are used as arguments
  *  to mach_port_allocate, mach_port_get_refs, etc, to specify
  *  a particular right to act upon.  The mach_port_names and
  *  The MACH_PORT_RIGHT_* definitions are used as arguments
  *  to mach_port_allocate, mach_port_get_refs, etc, to specify
  *  a particular right to act upon.  The mach_port_names and


@@ -256,11 +285,11 @@ typedef struct mach_port_status {
        boolean_t               mps_srights;    /* do send rights exist? */
        boolean_t               mps_pdrequest;  /* port-deleted requested? */
        boolean_t               mps_nsrequest;  /* no-senders requested? */
        boolean_t               mps_srights;    /* do send rights exist? */
        boolean_t               mps_pdrequest;  /* port-deleted requested? */
        boolean_t               mps_nsrequest;  /* no-senders requested? */

-       unsigned int            mps_flags;      /* port flags */
+       natural_t               mps_flags;              /* port flags */

 } mach_port_status_t;
 
 #define MACH_PORT_QLIMIT_DEFAULT       ((mach_port_msgcount_t) 5)
 } mach_port_status_t;
 
 #define MACH_PORT_QLIMIT_DEFAULT       ((mach_port_msgcount_t) 5)

-#define MACH_PORT_QLIMIT_MAX           ((mach_port_msgcount_t) 16)
+#define MACH_PORT_QLIMIT_MAX   ((mach_port_msgcount_t) 16)

 
 typedef struct mach_port_limits {
        mach_port_msgcount_t    mpl_qlimit;     /* number of msgs */
 
 typedef struct mach_port_limits {
        mach_port_msgcount_t    mpl_qlimit;     /* number of msgs */


@@ -274,17 +303,16 @@ typedef int       mach_port_flavor_t;
 #define MACH_PORT_RECEIVE_STATUS       2       /* uses mach_port_limits_t */
 #define MACH_PORT_DNREQUESTS_SIZE      3       /* info is int */
 
 #define MACH_PORT_RECEIVE_STATUS       2       /* uses mach_port_limits_t */
 #define MACH_PORT_DNREQUESTS_SIZE      3       /* info is int */
 

-#define MACH_PORT_LIMITS_INFO_COUNT \
-       (sizeof(mach_port_limits_t)/sizeof(natural_t))
-#define MACH_PORT_RECEIVE_STATUS_COUNT \
-       (sizeof(mach_port_status_t)/sizeof(natural_t))
+#define MACH_PORT_LIMITS_INFO_COUNT    ((natural_t) \
+       (sizeof(mach_port_limits_t)/sizeof(natural_t)))
+#define MACH_PORT_RECEIVE_STATUS_COUNT ((natural_t) \
+       (sizeof(mach_port_status_t)/sizeof(natural_t)))

 #define MACH_PORT_DNREQUESTS_SIZE_COUNT 1
 
 /*
  * Structure used to pass information about port allocation requests.
  * Must be padded to 64-bits total length.
  */
 #define MACH_PORT_DNREQUESTS_SIZE_COUNT 1
 
 /*
  * Structure used to pass information about port allocation requests.
  * Must be padded to 64-bits total length.
  */

-

 typedef struct mach_port_qos {
        boolean_t               name:1;         /* name given */
        boolean_t               prealloc:1;     /* prealloced message */
 typedef struct mach_port_qos {
        boolean_t               name:1;         /* name given */
        boolean_t               prealloc:1;     /* prealloced message */


@@ -292,4 +320,21 @@ typedef struct mach_port_qos {
        natural_t               len;
 } mach_port_qos_t;
 
        natural_t               len;
 } mach_port_qos_t;
 

+#if    !defined(_POSIX_C_SOURCE) && !defined(_NO_PORT_T_FROM_MACH)
+/*
+ *  Mach 3.0 renamed everything to have mach_ in front of it.
+ *  These types and macros are provided for backward compatibility
+ *     but are deprecated.
+ */
+typedef mach_port_t            port_t;
+typedef mach_port_name_t       port_name_t;
+typedef mach_port_name_t       *port_name_array_t;
+
+#define PORT_NULL              ((port_t) 0)
+#define PORT_DEAD              ((port_t) ~0)
+#define PORT_VALID(name) \
+               ((port_t)(name) != PORT_NULL && (port_t)(name) != PORT_DEAD)
+
+#endif /* !_POSIX_C_SOURCE && !_NO_PORT_T_FROM_MACH */
+

 #endif /* _MACH_PORT_H_ */
 #endif /* _MACH_PORT_H_ */