osfmk/kern/syscall_emulation.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and ditribute 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.
  35  *
  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 #include <mach/error.h>
  54 #include <mach/vm_param.h>
  55 #include <mach/boolean.h>
  56 #include <kern/misc_protos.h>
  57 #include <kern/syscall_emulation.h>
  58 #include <kern/task.h>
  59 #include <kern/kalloc.h>
  60 #include <vm/vm_kern.h>
  61 #include <machine/thread.h>     /* for syscall_emulation_sync */
  62
  63 /*
  64  * Exported interface
  65  */
  66
  67 /*
  68  * WARNING:
  69  * This code knows that kalloc() allocates memory most efficiently
  70  * in sizes that are powers of 2, and asks for those sizes.
  71  */
  72
  73 /*
  74  * Go from number of entries to size of struct eml_dispatch and back.
  75  */
  76 #define base_size       (sizeof(struct eml_dispatch) - sizeof(eml_routine_t))
  77 #define count_to_size(count) \
  78         (base_size + sizeof(vm_offset_t) * (count))
  79
  80 #define size_to_count(size) \
  81         ( ((size) - base_size) / sizeof(vm_offset_t) )
  82
  83 /* Forwards */
  84 kern_return_t
  85 task_set_emulation_vector_internal(
  86         task_t                  task,
  87         int                     vector_start,
  88         emulation_vector_t      emulation_vector,
  89         mach_msg_type_number_t  emulation_vector_count);
  90
  91 /*
  92  *  eml_init:   initialize user space emulation code
  93  */
  94 void
  95 eml_init(void)
  96 {
  97 }
  98
  99 /*
 100  * eml_task_reference() [Exported]
 101  *
 102  *      Bumps the reference count on the common emulation
 103  *      vector.
 104  */
 105
 106 void
 107 eml_task_reference(
 108         task_t  task,
 109         task_t  parent)
 110 {
 111         register eml_dispatch_t eml;
 112
 113         if (parent == TASK_NULL)
 114             eml = EML_DISPATCH_NULL;
 115         else
 116             eml = parent->eml_dispatch;
 117
 118         if (eml != EML_DISPATCH_NULL) {
 119             mutex_lock(&eml->lock);
 120             eml->ref_count++;
 121             mutex_unlock(&eml->lock);
 122         }
 123         task->eml_dispatch = eml;
 124 }
 125
 126
 127 /*
 128  * eml_task_deallocate() [Exported]
 129  *
 130  *      Cleans up after the emulation code when a process exits.
 131  */
 132
 133 void
 134 eml_task_deallocate(
 135         task_t task)
 136 {
 137         register eml_dispatch_t eml;
 138
 139         eml = task->eml_dispatch;
 140         if (eml != EML_DISPATCH_NULL) {
 141             int count;
 142
 143             mutex_lock(&eml->lock);
 144             count = --eml->ref_count;
 145             mutex_unlock(&eml->lock);
 146
 147             if (count == 0)
 148                 kfree((vm_offset_t)eml, count_to_size(eml->disp_count));
 149
 150             task->eml_dispatch = EML_DISPATCH_NULL;
 151         }
 152 }
 153
 154 /*
 155  *   task_set_emulation_vector:  [Server Entry]
 156  *   set a list of emulated system calls for this task.
 157  */
 158 kern_return_t
 159 task_set_emulation_vector_internal(
 160         task_t                  task,
 161         int                     vector_start,
 162         emulation_vector_t      emulation_vector,
 163         mach_msg_type_number_t  emulation_vector_count)
 164 {
 165         return KERN_NOT_SUPPORTED;
 166 }
 167
 168 /*
 169  *      task_set_emulation_vector:  [Server Entry]
 170  *
 171  *      Set the list of emulated system calls for this task.
 172  *      The list is out-of-line.
 173  */
 174 kern_return_t
 175 task_set_emulation_vector(
 176         task_t                  task,
 177         int                     vector_start,
 178         emulation_vector_t      emulation_vector,
 179         mach_msg_type_number_t  emulation_vector_count)
 180 {
 181         return KERN_NOT_SUPPORTED;
 182 }
 183
 184 /*
 185  *      task_get_emulation_vector: [Server Entry]
 186  *
 187  *      Get the list of emulated system calls for this task.
 188  *      List is returned out-of-line.
 189  */
 190 kern_return_t
 191 task_get_emulation_vector(
 192         task_t                  task,
 193         int                     *vector_start,                  /* out */
 194         emulation_vector_t      *emulation_vector,              /* out */
 195         mach_msg_type_number_t  *emulation_vector_count)        /* out */
 196 {
 197         return KERN_NOT_SUPPORTED;
 198 }
 199
 200 /*
 201  *   task_set_emulation:  [Server Entry]
 202  *   set up for user space emulation of syscalls within this task.
 203  */
 204 kern_return_t
 205 task_set_emulation(
 206         task_t          task,
 207         vm_offset_t     routine_entry_pt,
 208         int             routine_number)
 209 {
 210         return KERN_NOT_SUPPORTED;
 211 }
 212
 213
 214
 215