osfmk/ipc/ipc_table.h

   1 /*
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  28 /*
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  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989 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
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  39  * software, derivative works or modified versions, and any portions
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  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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  46  * Carnegie Mellon requests users of this software to return to
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  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
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  53  * any improvements or extensions that they make and grant Carnegie Mellon
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  55  */
  56 /*
  57  */
  58 /*
  59  *      File:   ipc/ipc_table.h
  60  *      Author: Rich Draves
  61  *      Date:   1989
  62  *
  63  *      Definitions for tables, used for IPC capabilities (ipc_entry_t)
  64  *      and dead-name requests (ipc_port_request_t).
  65  */
  66
  67 #ifndef _IPC_IPC_TABLE_H_
  68 #define _IPC_IPC_TABLE_H_
  69
  70 #include <mach/mach_types.h>
  71 #include <mach/boolean.h>
  72 #include <mach/vm_param.h>
  73
  74 #include <ipc/ipc_types.h>
  75
  76 /*
  77  *      The is_table_next field of an ipc_space_t points to
  78  *      an ipc_table_size structure.  These structures must
  79  *      be elements of an array, ipc_table_entries.
  80  *
  81  *      The array must end with two elements with the same its_size value.
  82  *      Except for the terminating element, the its_size values must
  83  *      be strictly increasing.  The largest (last) its_size value
  84  *      must be less than or equal to MACH_PORT_INDEX(MACH_PORT_DEAD).
  85  *      This ensures that
  86  *              1) MACH_PORT_INDEX(MACH_PORT_DEAD) isn't a valid index
  87  *              in the table, so ipc_entry_get won't allocate it.
  88  *              2) MACH_PORT_MAKE(index+1, 0) and MAKE_PORT_MAKE(size, 0)
  89  *              won't ever overflow.
  90  *
  91  *
  92  *      The ipr_size field of the first element in a table of
  93  *      dead-name requests (ipc_port_request_t) points to the
  94  *      ipc_table_size structure.  The structures must be elements
  95  *      of ipc_table_dnrequests.  ipc_table_dnrequests must end
  96  *      with an element with zero its_size, and except for this last
  97  *      element, the its_size values must be strictly increasing.
  98  *
  99  *      The is_table_next field points to the ipc_table_size structure
 100  *      for the next larger size of table, not the one currently in use.
 101  *      The ipr_size field points to the currently used ipc_table_size.
 102  */
 103
 104 struct ipc_table_size {
 105         ipc_table_elems_t its_size;     /* number of elements in table */
 106 };
 107
 108 extern ipc_table_size_t ipc_table_entries;
 109 extern ipc_table_size_t ipc_table_dnrequests;
 110
 111 /* Initialize IPC capabilities table storage */
 112 extern void ipc_table_init(void) __attribute__((section("__TEXT, initcode")));
 113
 114 /*
 115  *      Note that ipc_table_alloc, ipc_table_realloc, and ipc_table_free
 116  *      all potentially use the VM system.  Hence simple locks can't
 117  *      be held across them.
 118  *
 119  *      We can't use a copying realloc, because the realloc happens
 120  *      with the data unlocked.  ipc_table_realloc remaps the data,
 121  *      so it is OK.
 122  */
 123
 124 /* Allocate a table */
 125 extern void * ipc_table_alloc(
 126         vm_size_t       size);
 127
 128 /* Reallocate a big table */
 129 extern void * ipc_table_realloc(
 130         vm_size_t       old_size,
 131         void *          old_table,
 132         vm_size_t       new_size);
 133
 134 /* Free a table */
 135 extern void ipc_table_free(
 136         vm_size_t       size,
 137         void *          table);
 138
 139 #define it_entries_reallocable(its)                                     \
 140         ((its)->its_size * sizeof(struct ipc_entry) >= PAGE_SIZE)
 141
 142 #define it_entries_alloc(its)                                           \
 143         ((ipc_entry_t)                                                  \
 144         ipc_table_alloc(it_entries_reallocable(its) ?                   \
 145             round_page((its)->its_size * sizeof(struct ipc_entry)) :    \
 146             (its)->its_size * sizeof(struct ipc_entry)                  \
 147         ))
 148
 149 #define it_entries_realloc(its, table, nits)                            \
 150         ((ipc_entry_t)                                                  \
 151         ipc_table_realloc(                                              \
 152             round_page((its)->its_size * sizeof(struct ipc_entry)),     \
 153             (void *)(table),                                    \
 154             round_page((nits)->its_size * sizeof(struct ipc_entry))     \
 155         ))
 156
 157 #define it_entries_free(its, table)                                     \
 158         ipc_table_free(it_entries_reallocable(its) ?                    \
 159             round_page((its)->its_size * sizeof(struct ipc_entry)) :    \
 160             (its)->its_size * sizeof(struct ipc_entry),                 \
 161             (void *)(table)                                     \
 162         )
 163
 164 #define it_dnrequests_alloc(its)                                        \
 165         ((ipc_port_request_t)                                           \
 166          ipc_table_alloc((its)->its_size *                              \
 167                          sizeof(struct ipc_port_request)))
 168
 169 #define it_dnrequests_free(its, table)                                  \
 170         ipc_table_free((its)->its_size *                                \
 171                        sizeof(struct ipc_port_request),                 \
 172                        (void *)(table))
 173
 174 #endif  /* _IPC_IPC_TABLE_H_ */