src/mapi/mapi/stub.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.9
   4  *
   5  * Copyright (C) 2010 LunarG Inc.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  23  * DEALINGS IN THE SOFTWARE.
  24  *
  25  * Authors:
  26  *    Chia-I Wu <olv@lunarg.com>
  27  */
  28
  29 #include <stdlib.h>
  30 #include <stddef.h> /* for offsetof */
  31 #include <string.h>
  32 #include <assert.h>
  33
  34 #include "u_current.h"
  35 #include "u_thread.h"
  36 #include "entry.h"
  37 #include "stub.h"
  38 #include "table.h"
  39
  40 #define MAPI_TABLE_FIRST_DYNAMIC \
  41    (offsetof(struct mapi_table, dynamic0) / sizeof(mapi_func))
  42 #define MAPI_TABLE_NUM_DYNAMIC \
  43    ((offsetof(struct mapi_table, last) - \
  44      offsetof(struct mapi_table, dynamic0)) / sizeof(mapi_func))
  45 #define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
  46
  47 /*
  48  * This will define public_string_pool, public_sorted_indices, and
  49  * public_stubs.
  50  */
  51 #define MAPI_TMP_PUBLIC_STUBS
  52 #include "mapi_tmp.h"
  53
  54 static struct mapi_stub dynamic_stubs[MAPI_TABLE_NUM_DYNAMIC];
  55 static int num_dynamic_stubs;
  56 static int next_dynamic_slot = MAPI_TABLE_FIRST_DYNAMIC;
  57
  58 void
  59 stub_init_once(void)
  60 {
  61 #ifdef PTHREADS
  62    static pthread_once_t once = PTHREAD_ONCE_INIT;
  63    pthread_once(&once, entry_patch_public);
  64 #else
  65    static int first = 1;
  66    if (first) {
  67       first = 0;
  68       entry_patch_public();
  69    }
  70 #endif
  71 }
  72
  73 static int
  74 stub_compare(const void *key, const void *elem)
  75 {
  76    const char *name = (const char *) key;
  77    const int *index = (const int *) elem;
  78    const struct mapi_stub *stub;
  79    const char *stub_name;
  80
  81    stub = &public_stubs[*index];
  82    stub_name = &public_string_pool[(unsigned long) stub->name];
  83
  84    return strcmp(name, stub_name);
  85 }
  86
  87 /**
  88  * Return the public stub with the given name.
  89  */
  90 const struct mapi_stub *
  91 stub_find_public(const char *name)
  92 {
  93    const int *index;
  94
  95    index = (const int *) bsearch(name, public_sorted_indices,
  96          ARRAY_SIZE(public_sorted_indices) - 1,
  97          sizeof(public_sorted_indices[0]), stub_compare);
  98
  99    return (index) ? &public_stubs[*index] : NULL;
 100 }
 101
 102 /**
 103  * Add a dynamic stub.
 104  */
 105 static struct mapi_stub *
 106 stub_add_dynamic(const char *name)
 107 {
 108    struct mapi_stub *stub;
 109    int idx;
 110
 111    idx = num_dynamic_stubs;
 112    if (idx >= MAPI_TABLE_NUM_DYNAMIC)
 113       return NULL;
 114
 115    stub = &dynamic_stubs[idx];
 116
 117    /* dispatch to mapi_table->last, which is always no-op */
 118    stub->addr =
 119       entry_generate(MAPI_TABLE_FIRST_DYNAMIC + MAPI_TABLE_NUM_DYNAMIC);
 120    if (!stub->addr)
 121       return NULL;
 122
 123    stub->name = (const void *) name;
 124    /* to be fixed later */
 125    stub->slot = -1;
 126
 127    num_dynamic_stubs = idx + 1;
 128
 129    return stub;
 130 }
 131
 132 /**
 133  * Return the dynamic stub with the given name.  If no such stub exists and
 134  * generate is true, a new stub is generated.
 135  */
 136 struct mapi_stub *
 137 stub_find_dynamic(const char *name, int generate)
 138 {
 139    u_mutex_declare_static(dynamic_mutex);
 140    struct mapi_stub *stub = NULL;
 141    int count, i;
 142
 143    u_mutex_lock(dynamic_mutex);
 144
 145    if (generate)
 146       assert(!stub_find_public(name));
 147
 148    count = num_dynamic_stubs;
 149    for (i = 0; i < count; i++) {
 150       if (strcmp(name, (const char *) dynamic_stubs[i].name) == 0) {
 151          stub = &dynamic_stubs[i];
 152          break;
 153       }
 154    }
 155
 156    /* generate a dynamic stub */
 157    if (generate && !stub)
 158          stub = stub_add_dynamic(name);
 159
 160    u_mutex_unlock(dynamic_mutex);
 161
 162    return stub;
 163 }
 164
 165 void
 166 stub_fix_dynamic(struct mapi_stub *stub, const struct mapi_stub *alias)
 167 {
 168    int slot;
 169
 170    if (stub->slot >= 0)
 171       return;
 172
 173    if (alias)
 174       slot = alias->slot;
 175    else
 176       slot = next_dynamic_slot++;
 177
 178    entry_patch(stub->addr, slot);
 179    stub->slot = slot;
 180 }