summaryrefslogtreecommitdiff
path: root/dispatch/glproc_egl.cpp
blob: 07714ae86b1e09bdc3fb1d41029d86438e442caa (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
/**************************************************************************
 *
 * Copyright 2011 Jose Fonseca
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 **************************************************************************/


#include "glproc.hpp"


#if !defined(_WIN32)
#include "dlopen.hpp"
#endif


/*
 * Handle to the true OpenGL library.
 * XXX: Not really used yet.
 */
#if defined(_WIN32)
HMODULE _libGlHandle = NULL;
#else
void *_libGlHandle = NULL;
#endif



#if defined(_WIN32)

#error Unsupported

#elif defined(__APPLE__)

#error Unsupported

#else

/*
 * Lookup a public EGL/GL/GLES symbol
 *
 * The spec states that eglGetProcAddress should only be used for non-core
 * (extensions) entry-points.  Core entry-points should be taken directly from
 * the API specific libraries.
 *
 */
void *
_getPublicProcAddress(const char *procName)
{
    void *proc;

    /*
     * We rely on dlsym(RTLD_NEXT, ...) whenever we can, because certain gl*
     * symbols are exported by multiple APIs/SOs, and it's not trivial to
     * determine which API/SO we should get the current symbol from.
     */
    proc = dlsym(RTLD_NEXT, procName);
    if (proc) {
        return proc;
    }

    /*
     * dlsym(RTLD_NEXT, ...) will fail when the SO containing the symbol was
     * loaded with RTLD_LOCAL.  We try to override RTLD_LOCAL with RTLD_GLOBAL
     * when tracing but this doesn't always work.  So we try to guess and load
     * the shared object directly.
     *
     * See https://github.com/apitrace/apitrace/issues/349#issuecomment-113316990
     */

    if (procName[0] == 'e' && procName[1] == 'g' && procName[2] == 'l') {
        static void *libEGL = NULL;
        if (!libEGL) {
            libEGL = _dlopen("libEGL.so", RTLD_LOCAL | RTLD_LAZY);
            if (!libEGL) {
                return NULL;
            }
        }
        return dlsym(libEGL, procName);
    }

    /*
     * This might happen when:
     *
     * - the application is querying non-extensions functions via
     *   eglGetProcAddress (either because EGL_KHR_get_all_proc_addresses
     *   is advertised, or merely because the EGL implementation supports
     *   it regardless, like Mesa does)
     *
     * - libGLES*.so nor libGL*.so was ever loaded.
     *
     * - we need to resolve entrypoints that application never asked (e.g.,
     *   glGetIntegerv), for internal purposes
     *
     * Therefore, we try to fallback to eglGetProcAddress.
     *
     * See https://github.com/apitrace/apitrace/issues/301#issuecomment-68532248
     */
    if (strcmp(procName, "eglGetProcAddress") != 0) {
        proc = (void *) _eglGetProcAddress(procName);
        if (proc) {
            return proc;
        }
    }

    /*
     * TODO: We could futher mitigate against using the wrong SO by:
     * - using RTLD_NOLOAD to ensure we only use an existing SO
     * - the determine the right SO via eglQueryAPI and glGetString(GL_VERSION)
     */

    if (procName[0] == 'g' && procName[1] == 'l') {
        /* TODO: Use GLESv1/GLESv2 on a per-context basis. */

        static void *libGLESv2 = NULL;
        if (!libGLESv2) {
            libGLESv2 = _dlopen("libGLESv2.so", RTLD_LOCAL | RTLD_LAZY);
        }
        if (libGLESv2) {
            proc = dlsym(libGLESv2, procName);
        }
        if (proc) {
            return proc;
        }

        static void *libGLESv1 = NULL;
        if (!libGLESv1) {
            libGLESv1 = _dlopen("libGLESv1_CM.so", RTLD_LOCAL | RTLD_LAZY);
        }
        if (libGLESv1) {
            proc = dlsym(libGLESv1, procName);
        }
        if (proc) {
            return proc;
        }
    }

    return NULL;
}

/*
 * Lookup a private EGL/GL/GLES symbol
 *
 * Private symbols should always be available through eglGetProcAddress, and
 * they are guaranteed to work with any context bound (regardless of the API).
 *
 * However, per issue#57, eglGetProcAddress returns garbage on some
 * implementations, and the spec states that implementations may choose to also
 * export extension functions publicly, so we always attempt dlsym before
 * eglGetProcAddress to mitigate that.
 */
void *
_getPrivateProcAddress(const char *procName)
{
    void *proc;
    proc = _getPublicProcAddress(procName);
    if (!proc &&
        ((procName[0] == 'e' && procName[1] == 'g' && procName[2] == 'l') ||
         (procName[0] == 'g' && procName[1] == 'l'))) {
        proc = (void *) _eglGetProcAddress(procName);
    }

    return proc;
}

#endif