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Annotation of kernel/ipc/ipc_pset.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
        !             7:  * Reserved.  This file contains Original Code and/or Modifications of
        !             8:  * Original Code as defined in and that are subject to the Apple Public
        !             9:  * Source License Version 1.1 (the "License").  You may not use this file
        !            10:  * except in compliance with the License.  Please obtain a copy of the
        !            11:  * License at http://www.apple.com/publicsource and read it before using
        !            12:  * this file.
        !            13:  * 
        !            14:  * The Original Code and all software distributed under the License are
        !            15:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            19:  * License for the specific language governing rights and limitations
        !            20:  * under the License.
        !            21:  * 
        !            22:  * @APPLE_LICENSE_HEADER_END@
        !            23:  */
        !            24: 
        !            25: /*
        !            26:  * Copyright (c) 1995, 1994, 1993, 1992, 1991, 1990  
        !            27:  * Open Software Foundation, Inc. 
        !            28:  *  
        !            29:  * Permission to use, copy, modify, and distribute this software and 
        !            30:  * its documentation for any purpose and without fee is hereby granted, 
        !            31:  * provided that the above copyright notice appears in all copies and 
        !            32:  * that both the copyright notice and this permission notice appear in 
        !            33:  * supporting documentation, and that the name of ("OSF") or Open Software 
        !            34:  * Foundation not be used in advertising or publicity pertaining to 
        !            35:  * distribution of the software without specific, written prior permission. 
        !            36:  *  
        !            37:  * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE 
        !            38:  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
        !            39:  * FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL OSF BE LIABLE FOR ANY 
        !            40:  * SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 
        !            41:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN 
        !            42:  * ACTION OF CONTRACT, NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING 
        !            43:  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE 
        !            44:  */
        !            45: /*
        !            46:  * OSF Research Institute MK6.1 (unencumbered) 1/31/1995
        !            47:  */
        !            48: /* 
        !            49:  * Mach Operating System
        !            50:  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
        !            51:  * All Rights Reserved.
        !            52:  * 
        !            53:  * Permission to use, copy, modify and distribute this software and its
        !            54:  * documentation is hereby granted, provided that both the copyright
        !            55:  * notice and this permission notice appear in all copies of the
        !            56:  * software, derivative works or modified versions, and any portions
        !            57:  * thereof, and that both notices appear in supporting documentation.
        !            58:  * 
        !            59:  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
        !            60:  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
        !            61:  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
        !            62:  * 
        !            63:  * Carnegie Mellon requests users of this software to return to
        !            64:  * 
        !            65:  *  Software Distribution Coordinator  or  [email protected]
        !            66:  *  School of Computer Science
        !            67:  *  Carnegie Mellon University
        !            68:  *  Pittsburgh PA 15213-3890
        !            69:  * 
        !            70:  * any improvements or extensions that they make and grant Carnegie Mellon
        !            71:  * the rights to redistribute these changes.
        !            72:  */
        !            73: /*
        !            74:  *     File:   ipc/ipc_pset.c
        !            75:  *     Author: Rich Draves
        !            76:  *     Date:   1989
        !            77:  *
        !            78:  *     Functions to manipulate IPC port sets.
        !            79:  */
        !            80: 
        !            81: #include <mach/port.h>
        !            82: #include <mach/kern_return.h>
        !            83: #include <mach/message.h>
        !            84: #include <ipc/ipc_mqueue.h>
        !            85: #include <ipc/ipc_object.h>
        !            86: #include <ipc/ipc_pset.h>
        !            87: #include <ipc/ipc_right.h>
        !            88: #include <ipc/ipc_space.h>
        !            89: 
        !            90: /*
        !            91:  * Forward declarations
        !            92:  */
        !            93: void ipc_pset_add(
        !            94:        ipc_pset_t      pset,
        !            95:        ipc_port_t      port);
        !            96: 
        !            97: /*
        !            98:  *     Routine:        ipc_pset_alloc
        !            99:  *     Purpose:
        !           100:  *             Allocate a port set.
        !           101:  *     Conditions:
        !           102:  *             Nothing locked.  If successful, the port set is returned
        !           103:  *             locked.  (The caller doesn't have a reference.)
        !           104:  *     Returns:
        !           105:  *             KERN_SUCCESS            The port set is allocated.
        !           106:  *             KERN_INVALID_TASK       The space is dead.
        !           107:  *             KERN_NO_SPACE           No room for an entry in the space.
        !           108:  *             KERN_RESOURCE_SHORTAGE  Couldn't allocate memory.
        !           109:  */
        !           110: 
        !           111: kern_return_t
        !           112: ipc_pset_alloc(
        !           113:        ipc_space_t     space,
        !           114:        mach_port_t     *namep,
        !           115:        ipc_pset_t      *psetp)
        !           116: {
        !           117:        ipc_pset_t pset;
        !           118:        mach_port_t name;
        !           119:        kern_return_t kr;
        !           120: 
        !           121:        kr = ipc_object_alloc(space, IOT_PORT_SET,
        !           122:                              MACH_PORT_TYPE_PORT_SET, 0,
        !           123:                              &name, (ipc_object_t *) &pset);
        !           124:        if (kr != KERN_SUCCESS)
        !           125:                return kr;
        !           126:        /* pset is locked */
        !           127: 
        !           128:        pset->ips_local_name = name;
        !           129:        ipc_mqueue_init(&pset->ips_messages);
        !           130: 
        !           131:        *namep = name;
        !           132:        *psetp = pset;
        !           133:        return KERN_SUCCESS;
        !           134: }
        !           135: 
        !           136: /*
        !           137:  *     Routine:        ipc_pset_alloc_name
        !           138:  *     Purpose:
        !           139:  *             Allocate a port set, with a specific name.
        !           140:  *     Conditions:
        !           141:  *             Nothing locked.  If successful, the port set is returned
        !           142:  *             locked.  (The caller doesn't have a reference.)
        !           143:  *     Returns:
        !           144:  *             KERN_SUCCESS            The port set is allocated.
        !           145:  *             KERN_INVALID_TASK       The space is dead.
        !           146:  *             KERN_NAME_EXISTS        The name already denotes a right.
        !           147:  *             KERN_RESOURCE_SHORTAGE  Couldn't allocate memory.
        !           148:  */
        !           149: 
        !           150: kern_return_t
        !           151: ipc_pset_alloc_name(
        !           152:        ipc_space_t     space,
        !           153:        mach_port_t     name,
        !           154:        ipc_pset_t      *psetp)
        !           155: {
        !           156:        ipc_pset_t pset;
        !           157:        kern_return_t kr;
        !           158: 
        !           159:        kr = ipc_object_alloc_name(space, IOT_PORT_SET,
        !           160:                                   MACH_PORT_TYPE_PORT_SET, 0,
        !           161:                                   name, (ipc_object_t *) &pset);
        !           162:        if (kr != KERN_SUCCESS)
        !           163:                return kr;
        !           164:        /* pset is locked */
        !           165: 
        !           166:        pset->ips_local_name = name;
        !           167:        ipc_mqueue_init(&pset->ips_messages);
        !           168: 
        !           169:        *psetp = pset;
        !           170:        return KERN_SUCCESS;
        !           171: }
        !           172: 
        !           173: /*
        !           174:  *     Routine:        ipc_pset_add
        !           175:  *     Purpose:
        !           176:  *             Puts a port into a port set.
        !           177:  *             The port set gains a reference.
        !           178:  *     Conditions:
        !           179:  *             Both port and port set are locked and active.
        !           180:  *             The port isn't already in a set.
        !           181:  *             The owner of the port set is also receiver for the port.
        !           182:  */
        !           183: 
        !           184: void
        !           185: ipc_pset_add(
        !           186:        ipc_pset_t      pset,
        !           187:        ipc_port_t      port)
        !           188: {
        !           189:        assert(ips_active(pset));
        !           190:        assert(ip_active(port));
        !           191:        assert(port->ip_pset == IPS_NULL);
        !           192: 
        !           193:        port->ip_pset = pset;
        !           194:        ips_reference(pset);
        !           195: 
        !           196:        imq_lock(&port->ip_messages);
        !           197:        imq_lock(&pset->ips_messages);
        !           198: 
        !           199:        /* move messages from port's queue to the port set's queue */
        !           200: 
        !           201:        ipc_mqueue_move(&pset->ips_messages, &port->ip_messages, port);
        !           202:        imq_unlock(&pset->ips_messages);
        !           203:        assert(ipc_kmsg_queue_empty(&port->ip_messages.imq_messages));
        !           204: 
        !           205:        /* wake up threads waiting to receive from the port */
        !           206: 
        !           207:        ipc_mqueue_changed(&port->ip_messages, MACH_RCV_PORT_CHANGED);
        !           208:        assert(ipc_thread_queue_empty(&port->ip_messages.imq_threads));
        !           209:        imq_unlock(&port->ip_messages);
        !           210: }
        !           211: 
        !           212: /*
        !           213:  *     Routine:        ipc_pset_remove
        !           214:  *     Purpose:
        !           215:  *             Removes a port from a port set.
        !           216:  *             The port set loses a reference.
        !           217:  *     Conditions:
        !           218:  *             Both port and port set are locked.
        !           219:  *             The port must be active.
        !           220:  */
        !           221: 
        !           222: void
        !           223: ipc_pset_remove(
        !           224:        ipc_pset_t      pset,
        !           225:        ipc_port_t      port)
        !           226: {
        !           227:        assert(ip_active(port));
        !           228:        assert(port->ip_pset == pset);
        !           229: 
        !           230:        port->ip_pset = IPS_NULL;
        !           231:        ips_release(pset);
        !           232: 
        !           233:        imq_lock(&port->ip_messages);
        !           234:        imq_lock(&pset->ips_messages);
        !           235: 
        !           236:        /* move messages from port set's queue to the port's queue */
        !           237: 
        !           238:        ipc_mqueue_move(&port->ip_messages, &pset->ips_messages, port);
        !           239: 
        !           240:        imq_unlock(&pset->ips_messages);
        !           241:        imq_unlock(&port->ip_messages);
        !           242: }
        !           243: 
        !           244: /*
        !           245:  *     Routine:        ipc_pset_move
        !           246:  *     Purpose:
        !           247:  *             If nset is IPS_NULL, removes port
        !           248:  *             from the port set it is in.  Otherwise, adds
        !           249:  *             port to nset, removing it from any set
        !           250:  *             it might already be in.
        !           251:  *     Conditions:
        !           252:  *             The space is read-locked.
        !           253:  *     Returns:
        !           254:  *             KERN_SUCCESS            Moved the port.
        !           255:  *             KERN_NOT_IN_SET         nset is null and port isn't in a set.
        !           256:  */
        !           257: 
        !           258: kern_return_t
        !           259: ipc_pset_move(
        !           260:        ipc_space_t     space,
        !           261:        ipc_port_t      port,
        !           262:        ipc_pset_t      nset)
        !           263: {
        !           264:        ipc_pset_t oset;
        !           265: 
        !           266:        /*
        !           267:         *      While we've got the space locked, it holds refs for
        !           268:         *      the port and nset (because of the entries).  Also,
        !           269:         *      they must be alive.  While we've got port locked, it
        !           270:         *      holds a ref for oset, which might not be alive.
        !           271:         */
        !           272: 
        !           273:        ip_lock(port);
        !           274:        assert(ip_active(port));
        !           275: 
        !           276:        oset = port->ip_pset;
        !           277: 
        !           278:        if (oset == nset) {
        !           279:                /* the port is already in the new set:  a noop */
        !           280: 
        !           281:                is_read_unlock(space);
        !           282:        } else if (oset == IPS_NULL) {
        !           283:                /* just add port to the new set */
        !           284: 
        !           285:                ips_lock(nset);
        !           286:                assert(ips_active(nset));
        !           287:                is_read_unlock(space);
        !           288: 
        !           289:                ipc_pset_add(nset, port);
        !           290: 
        !           291:                ips_unlock(nset);
        !           292:        } else if (nset == IPS_NULL) {
        !           293:                /* just remove port from the old set */
        !           294: 
        !           295:                is_read_unlock(space);
        !           296:                ips_lock(oset);
        !           297: 
        !           298:                ipc_pset_remove(oset, port);
        !           299: 
        !           300:                if (ips_active(oset))
        !           301:                        ips_unlock(oset);
        !           302:                else {
        !           303:                        ips_check_unlock(oset);
        !           304:                        oset = IPS_NULL; /* trigger KERN_NOT_IN_SET */
        !           305:                }
        !           306:        } else {
        !           307:                /* atomically move port from oset to nset */
        !           308: 
        !           309:                if (oset < nset) {
        !           310:                        ips_lock(oset);
        !           311:                        ips_lock(nset);
        !           312:                } else {
        !           313:                        ips_lock(nset);
        !           314:                        ips_lock(oset);
        !           315:                }
        !           316: 
        !           317:                is_read_unlock(space);
        !           318:                assert(ips_active(nset));
        !           319: 
        !           320:                ipc_pset_remove(oset, port);
        !           321:                ipc_pset_add(nset, port);
        !           322: 
        !           323:                ips_unlock(nset);
        !           324:                ips_check_unlock(oset); /* KERN_NOT_IN_SET not a possibility */
        !           325:        }
        !           326: 
        !           327:        ip_unlock(port);
        !           328: 
        !           329:        return (((nset == IPS_NULL) && (oset == IPS_NULL)) ?
        !           330:                KERN_NOT_IN_SET : KERN_SUCCESS);
        !           331: }
        !           332: 
        !           333: /*
        !           334:  *     Routine:        ipc_pset_destroy
        !           335:  *     Purpose:
        !           336:  *             Destroys a port_set.
        !           337:  *
        !           338:  *             Doesn't remove members from the port set;
        !           339:  *             that happens lazily.  As members are removed,
        !           340:  *             their messages are removed from the queue.
        !           341:  *     Conditions:
        !           342:  *             The port_set is locked and alive.
        !           343:  *             The caller has a reference, which is consumed.
        !           344:  *             Afterwards, the port_set is unlocked and dead.
        !           345:  */
        !           346: 
        !           347: void
        !           348: ipc_pset_destroy(
        !           349:        ipc_pset_t      pset)
        !           350: {
        !           351:        assert(ips_active(pset));
        !           352: 
        !           353:        pset->ips_object.io_bits &= ~IO_BITS_ACTIVE;
        !           354: 
        !           355:        imq_lock(&pset->ips_messages);
        !           356:        ipc_mqueue_changed(&pset->ips_messages, MACH_RCV_PORT_DIED);
        !           357:        imq_unlock(&pset->ips_messages);
        !           358: 
        !           359:        ips_release(pset);      /* consume the ref our caller gave us */
        !           360:        ips_check_unlock(pset);
        !           361: }

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