/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
/*
* 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_
#define _MACH_PORT_H_
+#include <stdint.h>
#include <mach/boolean.h>
#include <mach/machine/vm_types.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.
*/
-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
-#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.
+ *
+ */
-#include <ipc/ipc_types.h>
-typedef ipc_port_t port_t;
+#ifndef MACH_KERNEL_PRIVATE
+/*
+ * For kernel code that resides outside of Mach proper, we opaque the
+ * port structure definition.
+ */
+struct ipc_port ;
+
+#endif /* MACH_KERNEL_PRIVATE */
+
+typedef struct ipc_port *ipc_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)
+
+typedef ipc_port_t mach_port_t;
+
+#else /* KERNEL */
+
+/*
+ * 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 */
-#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
- * 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.
*/
-#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)
(((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)
-#else
+
+#else /* NO_PORT_GEN */
+
#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
typedef natural_t mach_port_rights_t; /* number of rights */
/*
- * A port may have NMS detection enabled, in which case
- * it tracks outstanding send rights. Otherwise, there
- * is no information available about outstanding srights.
- * The return values are deliberately chosen to match
- * the old boolean (0=FALSE=no srights, 1=TRUE=srights,
- * 2=xxx=no information available).
+ * Are there outstanding send rights for a given port?
*/
-#define MACH_PORT_SRIGHTS_NONE 0 /* NMS: no srights */
-#define MACH_PORT_SRIGHTS_PRESENT 1 /* NMS: srights */
-#define MACH_PORT_SRIGHTS_NO_INFO 2 /* no NMS */
+#define MACH_PORT_SRIGHTS_NONE 0 /* no srights */
+#define MACH_PORT_SRIGHTS_PRESENT 1 /* srights */
typedef unsigned int mach_port_srights_t; /* status of send rights */
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? */
- 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)
-#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 */
#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.
*/
-
typedef struct mach_port_qos {
boolean_t name:1; /* name given */
boolean_t prealloc:1; /* prealloced message */
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_ */
projects / apple / xnu.git / blobdiff