/* * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * 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. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * 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 * 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. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * @OSF_COPYRIGHT@ */ /* * Mach Operating System * Copyright (c) 1991,1990,1989 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* */ /* * File: ipc/ipc_entry.h * Author: Rich Draves * Date: 1989 * * Definitions for translation entries, which represent * tasks' capabilities for ports and port sets. */ #ifndef _IPC_IPC_ENTRY_H_ #define _IPC_IPC_ENTRY_H_ #include <mach/mach_types.h> #include <mach/port.h> #include <mach/kern_return.h> #include <kern/kern_types.h> #include <kern/zalloc.h> #include <ipc/ipc_types.h> /* * Spaces hold capabilities for ipc_object_t's. * Each ipc_entry_t records a capability. Most capabilities have * small names, and the entries are elements of a table. * * The ie_index field of entries in the table implements * a ordered hash table with open addressing and linear probing. * * The ie_dist field holds the distance to the desired spot, * which is used to implement robin-hood hashing. * * This hash table converts (space, object) -> name. * It is used independently of the other fields. * * Free (unallocated) entries in the table have null ie_object * fields. The ie_bits field is zero except for IE_BITS_GEN. * The ie_next (ie_request) field links free entries into a free list. * * The first entry in the table (index 0) is always free. * It is used as the head of the free list. */ #define IPC_ENTRY_DIST_BITS 12 #define IPC_ENTRY_DIST_MAX ((1 << IPC_ENTRY_DIST_BITS) - 1) #define IPC_ENTRY_INDEX_BITS 20 #define IPC_ENTRY_INDEX_MAX ((1 << IPC_ENTRY_INDEX_BITS) - 1) struct ipc_entry { struct ipc_object *ie_object; ipc_entry_bits_t ie_bits; uint32_t ie_dist : IPC_ENTRY_DIST_BITS; mach_port_index_t ie_index : IPC_ENTRY_INDEX_BITS; union { mach_port_index_t next; /* next in freelist, or... */ ipc_table_index_t request; /* dead name request notify */ } index; }; #define ie_request index.request #define ie_next index.next #define IE_REQ_NONE 0 /* no request */ #define IE_BITS_UREFS_MASK 0x0000ffff /* 16 bits of user-reference */ #define IE_BITS_UREFS(bits) ((bits) & IE_BITS_UREFS_MASK) #define IE_BITS_TYPE_MASK 0x001f0000 /* 5 bits of capability type */ #define IE_BITS_TYPE(bits) ((bits) & IE_BITS_TYPE_MASK) #define IE_BITS_EXTYPE_MASK 0x00200000 /* 1 bit for extended capability */ #ifndef NO_PORT_GEN #define IE_BITS_GEN_MASK 0xff000000 /* 8 bits for generation */ #define IE_BITS_GEN(bits) ((bits) & IE_BITS_GEN_MASK) #define IE_BITS_GEN_ONE 0x04000000 /* low bit of generation */ #define IE_BITS_ROLL_POS 22 /* LSB pos of generation rollover */ #define IE_BITS_ROLL_BITS 2 /* number of generation rollover bits */ #define IE_BITS_ROLL_MASK (((1 << IE_BITS_ROLL_BITS) - 1) << IE_BITS_ROLL_POS) #define IE_BITS_ROLL(bits) ((((bits) & IE_BITS_ROLL_MASK) << 8) ^ IE_BITS_GEN_MASK) /* * Restart a generation counter with the specified bits for the rollover point. * There are 4 different rollover points: * bits rollover period * 0 0 64 * 0 1 48 * 1 0 32 * 1 1 16 */ static inline ipc_entry_bits_t ipc_entry_new_rollpoint( ipc_entry_bits_t rollbits) { rollbits = (rollbits << IE_BITS_ROLL_POS) & IE_BITS_ROLL_MASK; ipc_entry_bits_t newgen = IE_BITS_GEN_MASK + IE_BITS_GEN_ONE; return newgen | rollbits; } /* * Get the next gencount, modulo the entry's rollover point. If the sum rolls over, * the caller should re-start the generation counter with a different rollpoint. */ static inline ipc_entry_bits_t ipc_entry_new_gen( ipc_entry_bits_t oldgen) { ipc_entry_bits_t sum = (oldgen + IE_BITS_GEN_ONE) & IE_BITS_GEN_MASK; ipc_entry_bits_t roll = oldgen & IE_BITS_ROLL_MASK; ipc_entry_bits_t newgen = (sum % IE_BITS_ROLL(oldgen)) | roll; return newgen; } /* Determine if a gencount has rolled over or not. */ static inline boolean_t ipc_entry_gen_rolled( ipc_entry_bits_t oldgen, ipc_entry_bits_t newgen) { return (oldgen & IE_BITS_GEN_MASK) > (newgen & IE_BITS_GEN_MASK); } #else #define IE_BITS_GEN_MASK 0 #define IE_BITS_GEN(bits) 0 #define IE_BITS_GEN_ONE 0 #define IE_BITS_ROLL_POS 0 #define IE_BITS_ROLL_MASK 0 #define IE_BITS_ROLL(bits) (bits) static inline ipc_entry_bits_t ipc_entry_new_rollpoint( ipc_entry_bits_t rollbits) { return 0; } static inline ipc_entry_bits_t ipc_entry_new_gen( ipc_entry_bits_t oldgen) { return 0; } static inline boolean_t ipc_entry_gen_rolled( ipc_entry_bits_t oldgen, ipc_entry_bits_t newgen) { return FALSE; } #endif /* !USE_PORT_GEN */ #define IE_BITS_RIGHT_MASK 0x007fffff /* relevant to the right */ /* * Exported interfaces */ /* Search for entry in a space by name */ extern ipc_entry_t ipc_entry_lookup( ipc_space_t space, mach_port_name_t name); /* Hold a number of entries in a locked space */ extern kern_return_t ipc_entries_hold( ipc_space_t space, natural_t count); /* claim and initialize a held entry in a locked space */ extern kern_return_t ipc_entry_claim( ipc_space_t space, mach_port_name_t *namep, ipc_entry_t *entryp); /* Allocate an entry in a space */ extern kern_return_t ipc_entry_get( ipc_space_t space, mach_port_name_t *namep, ipc_entry_t *entryp); /* Allocate an entry in a space, growing the space if necessary */ extern kern_return_t ipc_entry_alloc( ipc_space_t space, mach_port_name_t *namep, ipc_entry_t *entryp); /* Allocate/find an entry in a space with a specific name */ extern kern_return_t ipc_entry_alloc_name( ipc_space_t space, mach_port_name_t name, ipc_entry_t *entryp); /* Deallocate an entry from a space */ extern void ipc_entry_dealloc( ipc_space_t space, mach_port_name_t name, ipc_entry_t entry); /* Mark and entry modified in a space */ extern void ipc_entry_modified( ipc_space_t space, mach_port_name_t name, ipc_entry_t entry); /* Grow the table in a space */ extern kern_return_t ipc_entry_grow_table( ipc_space_t space, ipc_table_elems_t target_size); /* mask on/off default entry generation bits */ extern mach_port_name_t ipc_entry_name_mask( mach_port_name_t name); #endif /* _IPC_IPC_ENTRY_H_ */