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      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 (at) 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 void
    157 stub_fix_dynamic(struct mapi_stub *stub, const struct mapi_stub *alias)
    158 {
    159    int slot;
    160 
    161    if (stub->slot >= 0)
    162       return;
    163 
    164    if (alias)
    165       slot = alias->slot;
    166    else
    167       slot = next_dynamic_slot++;
    168 
    169    entry_patch(stub->addr, slot);
    170    stub->slot = slot;
    171 }
    172 
    173 /**
    174  * Return the name of a stub.
    175  */
    176 const char *
    177 stub_get_name(const struct mapi_stub *stub)
    178 {
    179    const char *name;
    180 
    181    if (stub >= public_stubs &&
    182        stub < public_stubs + ARRAY_SIZE(public_stubs))
    183       name = &public_string_pool[(unsigned long) stub->name];
    184    else
    185       name = (const char *) stub->name;
    186 
    187    return name;
    188 }
    189 
    190 /**
    191  * Return the slot of a stub.
    192  */
    193 int
    194 stub_get_slot(const struct mapi_stub *stub)
    195 {
    196    return stub->slot;
    197 }
    198 
    199 /**
    200  * Return the address of a stub.
    201  */
    202 mapi_func
    203 stub_get_addr(const struct mapi_stub *stub)
    204 {
    205    assert(stub->addr || (unsigned int) stub->slot < MAPI_TABLE_NUM_STATIC);
    206    return (stub->addr) ? stub->addr : entry_get_public(stub->slot);
    207 }
    208