src/mapi/stub.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 2010 LunarG Inc.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  22  * DEALINGS IN THE SOFTWARE.
  23  *
  24  * Authors:
  25  *    Chia-I Wu <olv@lunarg.com>
  26  */
  27
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <assert.h>
  31 #include "c11/threads.h"
  32
  33 #include "util/macros.h"
  34 #include "u_current.h"
  35 #include "entry.h"
  36 #include "stub.h"
  37 #include "table.h"
  38
  39
  40 struct mapi_stub {
  41    const void *name;
  42    int slot;
  43    mapi_func addr;
  44 };
  45
  46 /* define public_string_pool and public_stubs */
  47 #define MAPI_TMP_PUBLIC_STUBS
  48 #include "mapi_tmp.h"
  49
  50 static struct mapi_stub dynamic_stubs[MAPI_TABLE_NUM_DYNAMIC];
  51 static int num_dynamic_stubs;
  52 static int next_dynamic_slot = MAPI_TABLE_NUM_STATIC;
  53
  54 void
  55 stub_init_once(void)
  56 {
  57    static once_flag flag = ONCE_FLAG_INIT;
  58    call_once(&flag, entry_patch_public);
  59 }
  60
  61 static int
  62 stub_compare(const void *key, const void *elem)
  63 {
  64    const char *name = (const char *) key;
  65    const struct mapi_stub *stub = (const struct mapi_stub *) elem;
  66    const char *stub_name;
  67
  68    stub_name = &public_string_pool[(unsigned long) stub->name];
  69
  70    return strcmp(name, stub_name);
  71 }
  72
  73 /**
  74  * Return the public stub with the given name.
  75  */
  76 const struct mapi_stub *
  77 stub_find_public(const char *name)
  78 {
  79    return (const struct mapi_stub *) bsearch(name, public_stubs,
  80          ARRAY_SIZE(public_stubs), sizeof(public_stubs[0]), stub_compare);
  81 }
  82
  83 /**
  84  * Add a dynamic stub.
  85  */
  86 static struct mapi_stub *
  87 stub_add_dynamic(const char *name)
  88 {
  89    struct mapi_stub *stub;
  90    int idx;
  91
  92    idx = num_dynamic_stubs;
  93    /* minus 1 to make sure we can never reach the last slot */
  94    if (idx >= MAPI_TABLE_NUM_DYNAMIC - 1)
  95       return NULL;
  96
  97    stub = &dynamic_stubs[idx];
  98
  99    /* dispatch to the last slot, which is reserved for no-op */
 100    stub->addr = entry_generate(
 101          MAPI_TABLE_NUM_STATIC + MAPI_TABLE_NUM_DYNAMIC - 1);
 102    if (!stub->addr)
 103       return NULL;
 104
 105    stub->name = (const void *) strdup(name);
 106    /* to be fixed later */
 107    stub->slot = -1;
 108
 109    num_dynamic_stubs = idx + 1;
 110
 111    return stub;
 112 }
 113
 114 /**
 115  * Return the dynamic stub with the given name.  If no such stub exists and
 116  * generate is true, a new stub is generated.
 117  */
 118 struct mapi_stub *
 119 stub_find_dynamic(const char *name, int generate)
 120 {
 121    static mtx_t dynamic_mutex = _MTX_INITIALIZER_NP;
 122    struct mapi_stub *stub = NULL;
 123    int count, i;
 124
 125    mtx_lock(&dynamic_mutex);
 126
 127    if (generate)
 128       assert(!stub_find_public(name));
 129
 130    count = num_dynamic_stubs;
 131    for (i = 0; i < count; i++) {
 132       if (strcmp(name, (const char *) dynamic_stubs[i].name) == 0) {
 133          stub = &dynamic_stubs[i];
 134          break;
 135       }
 136    }
 137
 138    /* generate a dynamic stub */
 139    if (generate && !stub)
 140          stub = stub_add_dynamic(name);
 141
 142    mtx_unlock(&dynamic_mutex);
 143
 144    return stub;
 145 }
 146
 147 static const struct mapi_stub *
 148 search_table_by_slot(const struct mapi_stub *table, size_t num_entries,
 149                      int slot)
 150 {
 151    size_t i;
 152    for (i = 0; i < num_entries; ++i) {
 153       if (table[i].slot == slot)
 154          return &table[i];
 155    }
 156    return NULL;
 157 }
 158
 159 const struct mapi_stub *
 160 stub_find_by_slot(int slot)
 161 {
 162    const struct mapi_stub *stub =
 163       search_table_by_slot(public_stubs, ARRAY_SIZE(public_stubs), slot);
 164    if (stub)
 165       return stub;
 166    return search_table_by_slot(dynamic_stubs, num_dynamic_stubs, slot);
 167 }
 168
 169 void
 170 stub_fix_dynamic(struct mapi_stub *stub, const struct mapi_stub *alias)
 171 {
 172    int slot;
 173
 174    if (stub->slot >= 0)
 175       return;
 176
 177    if (alias)
 178       slot = alias->slot;
 179    else
 180       slot = next_dynamic_slot++;
 181
 182    entry_patch(stub->addr, slot);
 183    stub->slot = slot;
 184 }
 185
 186 /**
 187  * Return the name of a stub.
 188  */
 189 const char *
 190 stub_get_name(const struct mapi_stub *stub)
 191 {
 192    const char *name;
 193
 194    if (stub >= public_stubs &&
 195        stub < public_stubs + ARRAY_SIZE(public_stubs))
 196       name = &public_string_pool[(unsigned long) stub->name];
 197    else
 198       name = (const char *) stub->name;
 199
 200    return name;
 201 }
 202
 203 /**
 204  * Return the slot of a stub.
 205  */
 206 int
 207 stub_get_slot(const struct mapi_stub *stub)
 208 {
 209    return stub->slot;
 210 }
 211
 212 /**
 213  * Return the address of a stub.
 214  */
 215 mapi_func
 216 stub_get_addr(const struct mapi_stub *stub)
 217 {
 218    assert(stub->addr || (unsigned int) stub->slot < MAPI_TABLE_NUM_STATIC);
 219    return (stub->addr) ? stub->addr : entry_get_public(stub->slot);
 220 }