osfmk/ipc/ipc_table.h

   1 /*
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   6  * The contents of this file constitute Original Code as defined in and
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  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
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  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50 /*
  51  */
  52 /*
  53  *      File:   ipc/ipc_table.h
  54  *      Author: Rich Draves
  55  *      Date:   1989
  56  *
  57  *      Definitions for tables, used for IPC capabilities (ipc_entry_t)
  58  *      and dead-name requests (ipc_port_request_t).
  59  */
  60
  61 #ifndef _IPC_IPC_TABLE_H_
  62 #define _IPC_IPC_TABLE_H_
  63
  64 #include <mach/mach_types.h>
  65 #include <mach/boolean.h>
  66 #include <mach/vm_param.h>
  67
  68 #include <ipc/ipc_types.h>
  69
  70 /*
  71  *      The is_table_next field of an ipc_space_t points to
  72  *      an ipc_table_size structure.  These structures must
  73  *      be elements of an array, ipc_table_entries.
  74  *
  75  *      The array must end with two elements with the same its_size value.
  76  *      Except for the terminating element, the its_size values must
  77  *      be strictly increasing.  The largest (last) its_size value
  78  *      must be less than or equal to MACH_PORT_INDEX(MACH_PORT_DEAD).
  79  *      This ensures that
  80  *              1) MACH_PORT_INDEX(MACH_PORT_DEAD) isn't a valid index
  81  *              in the table, so ipc_entry_get won't allocate it.
  82  *              2) MACH_PORT_MAKE(index+1, 0) and MAKE_PORT_MAKE(size, 0)
  83  *              won't ever overflow.
  84  *
  85  *
  86  *      The ipr_size field of the first element in a table of
  87  *      dead-name requests (ipc_port_request_t) points to the
  88  *      ipc_table_size structure.  The structures must be elements
  89  *      of ipc_table_dnrequests.  ipc_table_dnrequests must end
  90  *      with an element with zero its_size, and except for this last
  91  *      element, the its_size values must be strictly increasing.
  92  *
  93  *      The is_table_next field points to the ipc_table_size structure
  94  *      for the next larger size of table, not the one currently in use.
  95  *      The ipr_size field points to the currently used ipc_table_size.
  96  */
  97
  98 struct ipc_table_size {
  99         ipc_table_elems_t its_size;     /* number of elements in table */
 100 };
 101
 102 extern ipc_table_size_t ipc_table_entries;
 103 extern ipc_table_size_t ipc_table_dnrequests;
 104
 105 /* Initialize IPC capabilities table storage */
 106 extern void ipc_table_init(void);
 107
 108 /*
 109  *      Note that ipc_table_alloc, ipc_table_realloc, and ipc_table_free
 110  *      all potentially use the VM system.  Hence simple locks can't
 111  *      be held across them.
 112  *
 113  *      We can't use a copying realloc, because the realloc happens
 114  *      with the data unlocked.  ipc_table_realloc remaps the data,
 115  *      so it is OK.
 116  */
 117
 118 /* Allocate a table */
 119 extern void * ipc_table_alloc(
 120         vm_size_t       size);
 121
 122 /* Reallocate a big table */
 123 extern void * ipc_table_realloc(
 124         vm_size_t       old_size,
 125         void *          old_table,
 126         vm_size_t       new_size);
 127
 128 /* Free a table */
 129 extern void ipc_table_free(
 130         vm_size_t       size,
 131         void *          table);
 132
 133 #define it_entries_reallocable(its)                                     \
 134         ((its)->its_size * sizeof(struct ipc_entry) >= PAGE_SIZE)
 135
 136 #define it_entries_alloc(its)                                           \
 137         ((ipc_entry_t)                                                  \
 138         ipc_table_alloc(it_entries_reallocable(its) ?                   \
 139             round_page((its)->its_size * sizeof(struct ipc_entry)) :    \
 140             (its)->its_size * sizeof(struct ipc_entry)                  \
 141         ))
 142
 143 #define it_entries_realloc(its, table, nits)                            \
 144         ((ipc_entry_t)                                                  \
 145         ipc_table_realloc(                                              \
 146             round_page((its)->its_size * sizeof(struct ipc_entry)),     \
 147             (void *)(table),                                    \
 148             round_page((nits)->its_size * sizeof(struct ipc_entry))     \
 149         ))
 150
 151 #define it_entries_free(its, table)                                     \
 152         ipc_table_free(it_entries_reallocable(its) ?                    \
 153             round_page((its)->its_size * sizeof(struct ipc_entry)) :    \
 154             (its)->its_size * sizeof(struct ipc_entry),                 \
 155             (void *)(table)                                     \
 156         )
 157
 158 #define it_dnrequests_alloc(its)                                        \
 159         ((ipc_port_request_t)                                           \
 160          ipc_table_alloc((its)->its_size *                              \
 161                          sizeof(struct ipc_port_request)))
 162
 163 #define it_dnrequests_free(its, table)                                  \
 164         ipc_table_free((its)->its_size *                                \
 165                        sizeof(struct ipc_port_request),                 \
 166                        (void *)(table))
 167
 168 #endif  /* _IPC_IPC_TABLE_H_ */