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 <string.h>
  31 #include <assert.h>
  32
  33 #include "u_current.h"
  34 #include "u_thread.h"
  35 #include "entry.h"
  36 #include "stub.h"
  37 #include "table.h"
  38
  39 #define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
  40
  41 struct mapi_stub {
  42    const void *name;
  43    int slot;
  44    mapi_func addr;
  45 };
  46
  47 /* define public_string_pool and public_stubs */
  48 #define MAPI_TMP_PUBLIC_STUBS
  49 #include "mapi_tmp.h"
  50
  51 static struct mapi_stub dynamic_stubs[MAPI_TABLE_NUM_DYNAMIC];
  52 static int num_dynamic_stubs;
  53 static int next_dynamic_slot = MAPI_TABLE_NUM_STATIC;
  54
  55 void
  56 stub_init_once(void)
  57 {
  58 #ifdef HAVE_PTHREAD
  59    static pthread_once_t once = PTHREAD_ONCE_INIT;
  60    pthread_once(&once, entry_patch_public);
  61 #else
  62    static int first = 1;
  63    if (first) {
  64       first = 0;
  65       entry_patch_public();
  66    }
  67 #endif
  68 }
  69
  70 static int
  71 stub_compare(const void *key, const void *elem)
  72 {
  73    const char *name = (const char *) key;
  74    const struct mapi_stub *stub = (const struct mapi_stub *) elem;
  75    const char *stub_name;
  76
  77    stub_name = &public_string_pool[(unsigned long) stub->name];
  78
  79    return strcmp(name, stub_name);
  80 }
  81
  82 /**
  83  * Return the public stub with the given name.
  84  */
  85 const struct mapi_stub *
  86 stub_find_public(const char *name)
  87 {
  88    return (const struct mapi_stub *) bsearch(name, public_stubs,
  89          ARRAY_SIZE(public_stubs), sizeof(public_stubs[0]), stub_compare);
  90 }
  91
  92 /**
  93  * Add a dynamic stub.
  94  */
  95 static struct mapi_stub *
  96 stub_add_dynamic(const char *name)
  97 {
  98    struct mapi_stub *stub;
  99    int idx;
 100
 101    idx = num_dynamic_stubs;
 102    /* minus 1 to make sure we can never reach the last slot */
 103    if (idx >= MAPI_TABLE_NUM_DYNAMIC - 1)
 104       return NULL;
 105
 106    stub = &dynamic_stubs[idx];
 107
 108    /* dispatch to the last slot, which is reserved for no-op */
 109    stub->addr = entry_generate(
 110          MAPI_TABLE_NUM_STATIC + MAPI_TABLE_NUM_DYNAMIC - 1);
 111    if (!stub->addr)
 112       return NULL;
 113
 114    stub->name = (const void *) name;
 115    /* to be fixed later */
 116    stub->slot = -1;
 117
 118    num_dynamic_stubs = idx + 1;
 119
 120    return stub;
 121 }
 122
 123 /**
 124  * Return the dynamic stub with the given name.  If no such stub exists and
 125  * generate is true, a new stub is generated.
 126  */
 127 struct mapi_stub *
 128 stub_find_dynamic(const char *name, int generate)
 129 {
 130    u_mutex_declare_static(dynamic_mutex);
 131    struct mapi_stub *stub = NULL;
 132    int count, i;
 133
 134    u_mutex_lock(dynamic_mutex);
 135
 136    if (generate)
 137       assert(!stub_find_public(name));
 138
 139    count = num_dynamic_stubs;
 140    for (i = 0; i < count; i++) {
 141       if (strcmp(name, (const char *) dynamic_stubs[i].name) == 0) {
 142          stub = &dynamic_stubs[i];
 143          break;
 144       }
 145    }
 146
 147    /* generate a dynamic stub */
 148    if (generate && !stub)
 149          stub = stub_add_dynamic(name);
 150
 151    u_mutex_unlock(dynamic_mutex);
 152
 153    return stub;
 154 }
 155
 156 static const struct mapi_stub *
 157 search_table_by_slot(const struct mapi_stub *table, size_t num_entries,
 158                      int slot)
 159 {
 160    size_t i;
 161    for (i = 0; i < num_entries; ++i) {
 162       if (table[i].slot == slot)
 163          return &table[i];
 164    }
 165    return NULL;
 166 }
 167
 168 const struct mapi_stub *
 169 stub_find_by_slot(int slot)
 170 {
 171    const struct mapi_stub *stub =
 172       search_table_by_slot(public_stubs, ARRAY_SIZE(public_stubs), slot);
 173    if (stub)
 174       return stub;
 175    return search_table_by_slot(dynamic_stubs, num_dynamic_stubs, slot);
 176 }
 177
 178 void
 179 stub_fix_dynamic(struct mapi_stub *stub, const struct mapi_stub *alias)
 180 {
 181    int slot;
 182
 183    if (stub->slot >= 0)
 184       return;
 185
 186    if (alias)
 187       slot = alias->slot;
 188    else
 189       slot = next_dynamic_slot++;
 190
 191    entry_patch(stub->addr, slot);
 192    stub->slot = slot;
 193 }
 194
 195 /**
 196  * Return the name of a stub.
 197  */
 198 const char *
 199 stub_get_name(const struct mapi_stub *stub)
 200 {
 201    const char *name;
 202
 203    if (stub >= public_stubs &&
 204        stub < public_stubs + ARRAY_SIZE(public_stubs))
 205       name = &public_string_pool[(unsigned long) stub->name];
 206    else
 207       name = (const char *) stub->name;
 208
 209    return name;
 210 }
 211
 212 /**
 213  * Return the slot of a stub.
 214  */
 215 int
 216 stub_get_slot(const struct mapi_stub *stub)
 217 {
 218    return stub->slot;
 219 }
 220
 221 /**
 222  * Return the address of a stub.
 223  */
 224 mapi_func
 225 stub_get_addr(const struct mapi_stub *stub)
 226 {
 227    assert(stub->addr || (unsigned int) stub->slot < MAPI_TABLE_NUM_STATIC);
 228    return (stub->addr) ? stub->addr : entry_get_public(stub->slot);
 229 }