osfmk/mach/port.h

   1 /*
   2  * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  */
  58 /*
  59  *      File:   mach/port.h
  60  *
  61  *      Definition of a Mach port
  62  *
  63  *      Mach ports are the endpoints to Mach-implemented communications
  64  *      channels (usually uni-directional message queues, but other types
  65  *      also exist).
  66  *
  67  *      Unique collections of these endpoints are maintained for each
  68  *      Mach task.  Each Mach port in the task's collection is given a
  69  *      [task-local] name to identify it - and the the various "rights"
  70  *      held by the task for that specific endpoint.
  71  *
  72  *      This header defines the types used to identify these Mach ports
  73  *      and the various rights associated with them.  For more info see:
  74  *
  75  *      <mach/mach_port.h> - manipulation of port rights in a given space
  76  *      <mach/message.h> - message queue [and port right passing] mechanism
  77  *
  78  */
  79
  80 #ifndef _MACH_PORT_H_
  81 #define _MACH_PORT_H_
  82
  83 #include <stdint.h>
  84 #include <mach/boolean.h>
  85 #include <mach/machine/vm_types.h>
  86
  87 /*
  88  *      mach_port_name_t - the local identity for a Mach port
  89  *
  90  *      The name is Mach port namespace specific.  It is used to
  91  *      identify the rights held for that port by the task whose
  92  *      namespace is implied [or specifically provided].
  93  *
  94  *      Use of this type usually implies just a name - no rights.
  95  *      See mach_port_t for a type that implies a "named right."
  96  *
  97  */
  98
  99 typedef natural_t mach_port_name_t;
 100 typedef mach_port_name_t *mach_port_name_array_t;
 101
 102 #ifdef  KERNEL_PRIVATE
 103
 104 /*
 105  *      mach_port_t - a named port right
 106  *
 107  *      In the kernel, "rights" are represented [named] by pointers to
 108  *      the ipc port object in question. There is no port namespace for the
 109  *      rights to be collected.
 110  *
 111  *      Actually, there is namespace for the kernel task.  But most kernel
 112  *      code - including, but not limited to, Mach IPC code - lives in the
 113  *      limbo between the current user-level task and the "next" task. Very
 114  *      little of the kernel code runs in full kernel task context.  So very
 115  *      little of it gets to use the kernel task's port name space.
 116  *
 117  *      Because of this implementation approach, all in-kernel rights for
 118  *      a given port coalesce [have the same name/pointer].  The actual
 119  *      references are counted in the port itself.  It is up to the kernel
 120  *      code in question to "just remember" how many [and what type of]
 121  *      rights it holds and handle them appropriately.
 122  *
 123  */
 124
 125 #ifndef MACH_KERNEL_PRIVATE
 126 /*
 127  *      For kernel code that resides outside of Mach proper, we opaque the
 128  *      port structure definition.
 129  */
 130 struct ipc_port ;
 131
 132 #endif  /* MACH_KERNEL_PRIVATE */
 133
 134 typedef struct ipc_port         *ipc_port_t;
 135
 136 #define IPC_PORT_NULL           ((ipc_port_t) 0)
 137 #define IPC_PORT_DEAD           ((ipc_port_t)~0)
 138 #define IPC_PORT_VALID(port) \
 139         ((port) != IPC_PORT_NULL && (port) != IPC_PORT_DEAD)
 140
 141 typedef ipc_port_t              mach_port_t;
 142
 143 #else   /* KERNEL_PRIVATE */
 144
 145 /*
 146  *      mach_port_t - a named port right
 147  *
 148  *      In user-space, "rights" are represented by the name of the
 149  *      right in the Mach port namespace.  Even so, this type is
 150  *      presented as a unique one to more clearly denote the presence
 151  *      of a right coming along with the name.
 152  *
 153  *      Often, various rights for a port held in a single name space
 154  *      will coalesce and are, therefore, be identified by a single name
 155  *      [this is the case for send and receive rights].  But not
 156  *      always [send-once rights currently get a unique name for
 157  *      each right].
 158  *
 159  */
 160
 161 #ifndef _MACH_PORT_T
 162 #define _MACH_PORT_T
 163 typedef mach_port_name_t                mach_port_t;
 164 #endif
 165
 166 #endif  /* KERNEL_PRIVATE */
 167
 168 typedef mach_port_t                     *mach_port_array_t;
 169
 170 /*
 171  *  MACH_PORT_NULL is a legal value that can be carried in messages.
 172  *  It indicates the absence of any port or port rights.  (A port
 173  *  argument keeps the message from being "simple", even if the
 174  *  value is MACH_PORT_NULL.)  The value MACH_PORT_DEAD is also a legal
 175  *  value that can be carried in messages.  It indicates
 176  *  that a port right was present, but it died.
 177  */
 178
 179 #define MACH_PORT_NULL          0  /* intentional loose typing */
 180 #define MACH_PORT_DEAD          ((mach_port_name_t) ~0)
 181 #define MACH_PORT_VALID(name)                           \
 182                 (((name) != MACH_PORT_NULL) &&          \
 183                  ((name) != MACH_PORT_DEAD))
 184
 185
 186 /*
 187  *      For kernel-selected [assigned] port names, the name is
 188  *      comprised of two parts: a generation number and an index.
 189  *      This approach keeps the exact same name from being generated
 190  *      and reused too quickly [to catch right/reference counting bugs].
 191  *      The dividing line between the constituent parts is exposed so
 192  *      that efficient "mach_port_name_t to data structure pointer"
 193  *      conversion implementation can be made.  But it is possible
 194  *      for user-level code to assign their own names to Mach ports.
 195  *      These are not required to participate in this algorithm.  So
 196  *      care should be taken before "assuming" this model.
 197  *
 198  */
 199
 200 #ifndef NO_PORT_GEN
 201
 202 #define MACH_PORT_INDEX(name)           ((name) >> 8)
 203 #define MACH_PORT_GEN(name)             (((name) & 0xff) << 24)
 204 #define MACH_PORT_MAKE(index, gen)      \
 205                 (((index) << 8) | (gen) >> 24)
 206
 207 #else   /* NO_PORT_GEN */
 208
 209 #define MACH_PORT_INDEX(name)           (name)
 210 #define MACH_PORT_GEN(name)             (0)
 211 #define MACH_PORT_MAKE(index, gen)      (index)
 212
 213 #endif  /* NO_PORT_GEN */
 214
 215
 216 /*
 217  *  These are the different rights a task may have for a port.
 218  *  The MACH_PORT_RIGHT_* definitions are used as arguments
 219  *  to mach_port_allocate, mach_port_get_refs, etc, to specify
 220  *  a particular right to act upon.  The mach_port_names and
 221  *  mach_port_type calls return bitmasks using the MACH_PORT_TYPE_*
 222  *  definitions.  This is because a single name may denote
 223  *  multiple rights.
 224  */
 225
 226 typedef natural_t mach_port_right_t;
 227
 228 #define MACH_PORT_RIGHT_SEND            ((mach_port_right_t) 0)
 229 #define MACH_PORT_RIGHT_RECEIVE         ((mach_port_right_t) 1)
 230 #define MACH_PORT_RIGHT_SEND_ONCE       ((mach_port_right_t) 2)
 231 #define MACH_PORT_RIGHT_PORT_SET        ((mach_port_right_t) 3)
 232 #define MACH_PORT_RIGHT_DEAD_NAME       ((mach_port_right_t) 4)
 233 #define MACH_PORT_RIGHT_NUMBER          ((mach_port_right_t) 5)
 234
 235 typedef natural_t mach_port_type_t;
 236 typedef mach_port_type_t *mach_port_type_array_t;
 237
 238 #define MACH_PORT_TYPE(right)                                           \
 239                 ((mach_port_type_t)(((mach_port_type_t) 1)              \
 240                 << ((right) + ((mach_port_right_t) 16))))
 241 #define MACH_PORT_TYPE_NONE         ((mach_port_type_t) 0L)
 242 #define MACH_PORT_TYPE_SEND         MACH_PORT_TYPE(MACH_PORT_RIGHT_SEND)
 243 #define MACH_PORT_TYPE_RECEIVE      MACH_PORT_TYPE(MACH_PORT_RIGHT_RECEIVE)
 244 #define MACH_PORT_TYPE_SEND_ONCE    MACH_PORT_TYPE(MACH_PORT_RIGHT_SEND_ONCE)
 245 #define MACH_PORT_TYPE_PORT_SET     MACH_PORT_TYPE(MACH_PORT_RIGHT_PORT_SET)
 246 #define MACH_PORT_TYPE_DEAD_NAME    MACH_PORT_TYPE(MACH_PORT_RIGHT_DEAD_NAME)
 247
 248 /* Convenient combinations. */
 249
 250 #define MACH_PORT_TYPE_SEND_RECEIVE                                     \
 251                 (MACH_PORT_TYPE_SEND|MACH_PORT_TYPE_RECEIVE)
 252 #define MACH_PORT_TYPE_SEND_RIGHTS                                      \
 253                 (MACH_PORT_TYPE_SEND|MACH_PORT_TYPE_SEND_ONCE)
 254 #define MACH_PORT_TYPE_PORT_RIGHTS                                      \
 255                 (MACH_PORT_TYPE_SEND_RIGHTS|MACH_PORT_TYPE_RECEIVE)
 256 #define MACH_PORT_TYPE_PORT_OR_DEAD                                     \
 257                 (MACH_PORT_TYPE_PORT_RIGHTS|MACH_PORT_TYPE_DEAD_NAME)
 258 #define MACH_PORT_TYPE_ALL_RIGHTS                                       \
 259                 (MACH_PORT_TYPE_PORT_OR_DEAD|MACH_PORT_TYPE_PORT_SET)
 260
 261 /* Dummy type bits that mach_port_type/mach_port_names can return. */
 262
 263 #define MACH_PORT_TYPE_DNREQUEST        0x80000000
 264
 265 /* User-references for capabilities. */
 266
 267 typedef natural_t mach_port_urefs_t;
 268 typedef integer_t mach_port_delta_t;                    /* change in urefs */
 269
 270 /* Attributes of ports.  (See mach_port_get_receive_status.) */
 271
 272 typedef natural_t mach_port_seqno_t;            /* sequence number */
 273 typedef natural_t mach_port_mscount_t;          /* make-send count */
 274 typedef natural_t mach_port_msgcount_t;         /* number of msgs */
 275 typedef natural_t mach_port_rights_t;           /* number of rights */
 276
 277 /*
 278  *      Are there outstanding send rights for a given port?
 279  */
 280 #define MACH_PORT_SRIGHTS_NONE          0               /* no srights */
 281 #define MACH_PORT_SRIGHTS_PRESENT       1               /* srights */
 282 typedef unsigned int mach_port_srights_t;       /* status of send rights */
 283
 284 typedef struct mach_port_status {
 285         mach_port_name_t        mps_pset;       /* containing port set */
 286         mach_port_seqno_t       mps_seqno;      /* sequence number */
 287         mach_port_mscount_t     mps_mscount;    /* make-send count */
 288         mach_port_msgcount_t    mps_qlimit;     /* queue limit */
 289         mach_port_msgcount_t    mps_msgcount;   /* number in the queue */
 290         mach_port_rights_t      mps_sorights;   /* how many send-once rights */
 291         boolean_t               mps_srights;    /* do send rights exist? */
 292         boolean_t               mps_pdrequest;  /* port-deleted requested? */
 293         boolean_t               mps_nsrequest;  /* no-senders requested? */
 294         natural_t               mps_flags;              /* port flags */
 295 } mach_port_status_t;
 296
 297 #define MACH_PORT_QLIMIT_DEFAULT        ((mach_port_msgcount_t) 5)
 298 #define MACH_PORT_QLIMIT_MAX    ((mach_port_msgcount_t) 16)
 299
 300 typedef struct mach_port_limits {
 301         mach_port_msgcount_t    mpl_qlimit;     /* number of msgs */
 302 } mach_port_limits_t;
 303
 304 typedef integer_t *mach_port_info_t;            /* varying array of natural_t */
 305
 306 /* Flavors for mach_port_get/set_attributes() */
 307 typedef int     mach_port_flavor_t;
 308 #define MACH_PORT_LIMITS_INFO           1       /* uses mach_port_status_t */
 309 #define MACH_PORT_RECEIVE_STATUS        2       /* uses mach_port_limits_t */
 310 #define MACH_PORT_DNREQUESTS_SIZE       3       /* info is int */
 311
 312 #define MACH_PORT_LIMITS_INFO_COUNT     ((natural_t) \
 313         (sizeof(mach_port_limits_t)/sizeof(natural_t)))
 314 #define MACH_PORT_RECEIVE_STATUS_COUNT  ((natural_t) \
 315         (sizeof(mach_port_status_t)/sizeof(natural_t)))
 316 #define MACH_PORT_DNREQUESTS_SIZE_COUNT 1
 317
 318 /*
 319  * Structure used to pass information about port allocation requests.
 320  * Must be padded to 64-bits total length.
 321  */
 322 typedef struct mach_port_qos {
 323         boolean_t               name:1;         /* name given */
 324         boolean_t               prealloc:1;     /* prealloced message */
 325         boolean_t               pad1:30;
 326         natural_t               len;
 327 } mach_port_qos_t;
 328
 329 #if     !defined(_POSIX_C_SOURCE) && !defined(_NO_PORT_T_FROM_MACH)
 330 /*
 331  *  Mach 3.0 renamed everything to have mach_ in front of it.
 332  *  These types and macros are provided for backward compatibility
 333  *      but are deprecated.
 334  */
 335 typedef mach_port_t             port_t;
 336 typedef mach_port_name_t        port_name_t;
 337 typedef mach_port_name_t        *port_name_array_t;
 338
 339 #define PORT_NULL               ((port_t) 0)
 340 #define PORT_DEAD               ((port_t) ~0)
 341 #define PORT_VALID(name) \
 342                 ((port_t)(name) != PORT_NULL && (port_t)(name) != PORT_DEAD)
 343
 344 #endif  /* !_POSIX_C_SOURCE && !_NO_PORT_T_FROM_MACH */
 345
 346 #endif  /* _MACH_PORT_H_ */