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 ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
  41
  42 /* define public_string_pool and public_stubs */
  43 #define MAPI_TMP_PUBLIC_STUBS
  44 #include "mapi_tmp.h"
  45
  46 static struct mapi_stub dynamic_stubs[MAPI_TABLE_NUM_DYNAMIC];
  47 static int num_dynamic_stubs;
  48 static int next_dynamic_slot = MAPI_TABLE_NUM_STATIC;
  49
  50 void
  51 stub_init_once(void)
  52 {
  53 #ifdef PTHREADS
  54    static pthread_once_t once = PTHREAD_ONCE_INIT;
  55    pthread_once(&once, entry_patch_public);
  56 #else
  57    static int first = 1;
  58    if (first) {
  59       first = 0;
  60       entry_patch_public();
  61    }
  62 #endif
  63 }
  64
  65 static int
  66 stub_compare(const void *key, const void *elem)
  67 {
  68    const char *name = (const char *) key;
  69    const struct mapi_stub *stub = (const struct mapi_stub *) elem;
  70    const char *stub_name;
  71
  72    stub_name = &public_string_pool[(unsigned long) stub->name];
  73
  74    return strcmp(name, stub_name);
  75 }
  76
  77 /**
  78  * Return the public stub with the given name.
  79  */
  80 const struct mapi_stub *
  81 stub_find_public(const char *name)
  82 {
  83    return (const struct mapi_stub *) bsearch(name, public_stubs,
  84          ARRAY_SIZE(public_stubs), sizeof(public_stubs[0]), stub_compare);
  85 }
  86
  87 /**
  88  * Add a dynamic stub.
  89  */
  90 static struct mapi_stub *
  91 stub_add_dynamic(const char *name)
  92 {
  93    struct mapi_stub *stub;
  94    int idx;
  95
  96    idx = num_dynamic_stubs;
  97    /* minus 1 to make sure we can never reach the last slot */
  98    if (idx >= MAPI_TABLE_NUM_DYNAMIC - 1)
  99       return NULL;
 100
 101    stub = &dynamic_stubs[idx];
 102
 103    /* dispatch to the last slot, which is reserved for no-op */
 104    stub->addr = entry_generate(
 105          MAPI_TABLE_NUM_STATIC + MAPI_TABLE_NUM_DYNAMIC - 1);
 106    if (!stub->addr)
 107       return NULL;
 108
 109    stub->name = (const void *) name;
 110    /* to be fixed later */
 111    stub->slot = -1;
 112
 113    num_dynamic_stubs = idx + 1;
 114
 115    return stub;
 116 }
 117
 118 /**
 119  * Return the dynamic stub with the given name.  If no such stub exists and
 120  * generate is true, a new stub is generated.
 121  */
 122 struct mapi_stub *
 123 stub_find_dynamic(const char *name, int generate)
 124 {
 125    u_mutex_declare_static(dynamic_mutex);
 126    struct mapi_stub *stub = NULL;
 127    int count, i;
 128
 129    u_mutex_lock(dynamic_mutex);
 130
 131    if (generate)
 132       assert(!stub_find_public(name));
 133
 134    count = num_dynamic_stubs;
 135    for (i = 0; i < count; i++) {
 136       if (strcmp(name, (const char *) dynamic_stubs[i].name) == 0) {
 137          stub = &dynamic_stubs[i];
 138          break;
 139       }
 140    }
 141
 142    /* generate a dynamic stub */
 143    if (generate && !stub)
 144          stub = stub_add_dynamic(name);
 145
 146    u_mutex_unlock(dynamic_mutex);
 147
 148    return stub;
 149 }
 150
 151 void
 152 stub_fix_dynamic(struct mapi_stub *stub, const struct mapi_stub *alias)
 153 {
 154    int slot;
 155
 156    if (stub->slot >= 0)
 157       return;
 158
 159    if (alias)
 160       slot = alias->slot;
 161    else
 162       slot = next_dynamic_slot++;
 163
 164    entry_patch(stub->addr, slot);
 165    stub->slot = slot;
 166 }