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
stub_init_once(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
stub_compare(const void * key,const void * elem)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[(size_t) 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 *
stub_find_public(const char * name)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 *
stub_add_dynamic(const char * name)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 *
stub_find_dynamic(const char * name,int generate)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 *
search_table_by_slot(const struct mapi_stub * table,size_t num_entries,int slot)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 *
stub_find_by_slot(int slot)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
stub_fix_dynamic(struct mapi_stub * stub,const struct mapi_stub * alias)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 *
stub_get_name(const struct mapi_stub * stub)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[(size_t) 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
stub_get_slot(const struct mapi_stub * stub)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
stub_get_addr(const struct mapi_stub * stub)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 }
221