| commit | author | age | ||
| 6e58c7 | 1 | libglvnd: the GL Vendor-Neutral Dispatch library |
| AL | 2 | ================================================ |
| 3 | ||
| 4 | Introduction | |
| 5 | ------------ | |
| 6 | ||
| 7 | libglvnd is a vendor-neutral dispatch layer for arbitrating OpenGL API calls | |
| 8 | between multiple vendors. It allows multiple drivers from different vendors to | |
| 9 | coexist on the same filesystem, and determines which vendor to dispatch each | |
| 10 | API call to at runtime. | |
| 11 | ||
| 12 | Both GLX and EGL are supported, in any combination with OpenGL and OpenGL ES. | |
| 13 | ||
| 14 | libglvnd was originally described in Andy Ritger's OpenGL ABI proposal [1]. | |
| 15 | ||
| 16 | ||
| 17 | Building the library | |
| 18 | ---------------------- | |
| 19 | ||
| 20 | libglvnd build-depends on libx11, glproto and libxext. | |
| 21 | On Debian and derivatives, run: | |
| 22 | ||
| 23 | sudo apt-get install libxext-dev libx11-dev x11proto-gl-dev | |
| 24 | ||
| 25 | Run `./autogen.sh`, then run `./configure` and `make`. | |
| 26 | ||
| 27 | Alternatively you can use meson and ninja, which is much faster but should be | |
| 28 | otherwise the same (You will need packages from above too): | |
| 29 | ||
| 30 | sudo apt-get install ninja-build meson | |
| 31 | meson builddir | |
| 32 | ninja -C builddir | |
| 33 | ||
| 34 | Meson 0.48.0 is currently required, if your distro doesn't have meson 0.48 in | |
| 35 | the repos you can try the methods suggested | |
| 36 | [here](https://mesonbuild.com/Getting-meson.html). | |
| 37 | ||
| 38 | Code overview | |
| 39 | ------------- | |
| 40 | ||
| 41 | The code in the src/ directory is organized as follows: | |
| 42 | ||
| 43 | - GLX/ contains code for libGLX, the GLX window-system API library. | |
| 44 | - EGL/ contains code for libEGL, the EGL window-system API library. | |
| 45 | - GLdispatch/ contains code for libGLdispatch, which is responsible for | |
| 46 | dispatching OpenGL functions to the correct vendor library based on the | |
| 47 | current EGL or GLX rendering context. This implements the guts of the GL API | |
| 48 | libraries. Most of the dispatch code is based on Mesa's glapi. | |
| 49 | - OpenGL/, GLESv1/, and GLESv2/ contain code to generate libOpenGL.so, | |
| 50 | libGLESv1\_CM.so, and libGLESv2.so, respectively. All three are merely | |
| 51 | wrapper libraries for libGLdispatch. Ideally, these could be implemented via | |
| 52 | ELF symbol filtering, but in practice they need to be implemented manually. | |
| 53 | See the Issues section for details on why this is the case. | |
| 54 | - GL/ contains code for libGL. This is a wrapper around libGLdispatch and | |
| 55 | libGLX. | |
| 56 | - util/ contains generic utility code. | |
| 57 | ||
| 58 | In addition, libglvnd uses a GLX extension, | |
| 59 | [GLX\_EXT\_libglvnd](https://khronos.org/registry/OpenGL/extensions/EXT/GLX_EXT_libglvnd.txt), | |
| 60 | to determine which vendor library to use for a screen or XID. | |
| 61 | ||
| 62 | There are a few good starting points for familiarizing oneself with the code: | |
| 63 | ||
| 64 | - Look at the vendor-library to GLX ABI defined in `libglxabi.h`. | |
| 65 | - Follow the flow of `glXGetProcAddress() -> __glDispatchGetProcAddress() -> | |
| 66 | _glapi_get_proc_address()` to see how the dispatch table is updated as new GL | |
| 67 | stubs are generated, and how GLX looks for vendor-library-implemented | |
| 68 | dispatchers for GLX extension functions. | |
| 69 | - Follow the flow of `glXMakeContextCurrent() -> __glDispatchMakeCurrent() -> | |
| 70 | _glapi_set_current()` to see how the current dispatch table and state is | |
| 71 | updated by the API library. | |
| 72 | - Look at `libglxmapping.c:__glXLookupVendorBy{Name,Screen}()` to see how | |
| 73 | vendor library names are queried. | |
| 74 | - For EGL, follow the flow of `eglGetPlatformDisplay()` to see how EGL selects | |
| 75 | a vendor library. | |
| 76 | ||
| 77 | The tests/ directory contains several unit tests which verify that dispatching | |
| 78 | to different vendors actually works. Run `make check` to run these unit tests. | |
| 79 | ||
| 80 | Architecture | |
| 81 | ------------ | |
| 82 | ||
| 83 | The library organization differs slightly from that of Andy's original proposal. | |
| 84 | See the diagram below: | |
| 85 | ||
| 86 | <pre> | |
| 87 | ┌──────────────────────────────────┐ | |
| 88 | │ │ | |
| 89 | ┌─────┤ Application │ | |
| 90 | │ │ │ | |
| 91 | │ └─────┬───────────────────┬────────┘ | |
| 92 | │ │ │ | |
| 93 | │ ┌─────▾─────┐ │ ┌──────────────────────┐ | |
| 94 | │ │ │ │ │ │ | |
| 95 | │ │ libOpenGL │ │ │ │ | |
| 96 | │ │ │ │ │ X server │ | |
| 97 | │ └─────┬─────┘ │ │ │ | |
| 98 | │ DT_FILTER │ │ │ | |
| 99 | │ ┌─────▾──────────┐ ┌──────▾────────┐ │ ┌──────────────────┐ │ | |
| 100 | │ │ │ │ │ └─│GLX_EXT_libglvnd │─┘ | |
| 101 | │ │ [mapi/glapi] ◂─▸ │ │extension │ | |
| 102 | │ │ libGLdispatch │ │ libGLX ├─────────────▸──────────────────┘ | |
| 103 | │ │ │ │ ◂──────────┬─────────────────┐ | |
| 104 | │ └───────▴────────┘ └──────▴────────┘ │ │ | |
| 105 | │ DT_FILTER DT_FILTER ┌─▾─────────┐ ┌───▾────────┐ | |
| 106 | │ ┌───────┴─────────────────┴────────┐ │ │ │ │ | |
| 107 | │ │ │ │ │ │ │ | |
| 108 | └─────▸ libGL │ │ GLX_vendor│ │ GLX_vendor2│ | |
| 109 | └──────────────────────────────────┘ │ │ │ │ | |
| 110 | └───────────┘ └────────────┘ | |
| 111 | </pre> | |
| 112 | ||
| 113 | In this diagram, | |
| 114 | ||
| 115 | * `A ───▸ B` indicates that module A calls into module B. | |
| 116 | * `A ── DT_FILTER ──▸ B` indicates that DSO A is (logically) a filter library on | |
| 117 | DSO B. If ELF symbol filtering is enabled, symbols exported by A are resolved | |
| 118 | to entrypoints in B. | |
| 119 | ||
| 120 | libGLX manages loading GLX vendor libraries and dispatching GLX core and | |
| 121 | extension functions to the right vendor. | |
| 122 | ||
| 123 | GLX\_EXT\_libglvnd is a simple GLX extension which allows libGLX to determine | |
| 124 | the number of the screen belonging to an arbitrary drawable XID, and also the | |
| 125 | GL vendor to use for a given screen. | |
| 126 | ||
| 127 | libGLdispatch implements core GL dispatching and TLS. It acts as a thin wrapper | |
| 128 | around glapi which provides some higher-level functionality for managing | |
| 129 | dispatch tables, requesting vendor proc addresses, and making current to a given | |
| 130 | context + dispatch table. This is a separate library rather than statically | |
| 131 | linked into libGLX, since the same dispatching code is used by both GLX and | |
| 132 | EGL. | |
| 133 | ||
| 134 | libOpenGL is a wrapper library to libGLdispatch which exposes OpenGL 4.5 core and | |
| 135 | compatibility entry points. | |
| 136 | ||
| 137 | libGLESv{1,2} are wrapper libraries to libGLdispatch which expose OpenGL ES | |
| 138 | entrypoints. | |
| 139 | ||
| 140 | libGL is a wrapper library to libGLdispatch and libGLX which is provided for | |
| 141 | backwards-compatibility with applications which link against the old ABI. | |
| 142 | ||
| 143 | Note that since all OpenGL functions are dispatched through the same table in | |
| 144 | libGLdispatch, it doesn't matter which library is used to find the entrypoint. | |
| 145 | The same OpenGL function in libGL, libOpenGL, libGLES, and the function pointer | |
| 146 | returned by glXGetProcAddress are all interchangeable. | |
| 147 | ||
| 148 | ### OpenGL dispatching ### | |
| 149 | ||
| 150 | By definition, all OpenGL functions are dispatched based on the current | |
| 151 | context. OpenGL dispatching is handled in libGLdispatch, which is used by both | |
| 152 | EGL and GLX. | |
| 153 | ||
| 154 | libGLdispatch uses a per-thread dispatch table to look up the correct vendor | |
| 155 | library function for every OpenGL function. | |
| 156 | ||
| 157 | When an application calls eglMakeCurrent or glXMakeCurrent, the EGL or GLX | |
| 158 | library finds the correct dispatch table and then calls into libGLdispatch to | |
| 159 | set that table for the current thread. | |
| 160 | ||
| 161 | Since they're all dispatched through the common libGLdispatch layer, that also | |
| 162 | means that all OpenGL entrypoints will work correctly, regardless of whether | |
| 163 | the current context is from EGL or GLX. | |
| 164 | ||
| 165 | ### GLX dispatching ### | |
| 166 | ||
| 167 | Unlike core OpenGL functions, whose vendor can be determined from the current | |
| 168 | context, many GLX functions are context-independent. In order to successfully | |
| 169 | map GLX API calls to the right vendor, we use the following strategy: | |
| 170 | ||
| 171 | * Most GLX entry points specify (either explicitly, or implicitly) an | |
| 172 | X screen. | |
| 173 | ||
| 174 | * On a per-entry point basis, dispatch the call to the | |
| 175 | `libGLX_VENDOR.so` for that screen. | |
| 176 | ||
| 177 | * The first time `libGLX.so` gets called with a unique combination of X | |
| 178 | Display + screen, do the following: | |
| 179 | ||
| 180 | * Use the Display connection to query the X server for the GLX | |
| 181 | vendor of that X screen. | |
| 182 | ||
| 183 | * Load the corresponding `libGLX_VENDOR.so`. | |
| 184 | ||
| 185 | * Read the vendor's GLX dispatch table from the `libGLX_VENDOR.so`. | |
| 186 | ||
| 187 | * Cache that Display + screen <=> vendor dispatch table mapping, for | |
| 188 | use in subsequent dispatching. | |
| 189 | ||
| 190 | * Some GLX entry points imply an X screen by a GLX object they | |
| 191 | specify. Such GLX objects are: | |
| 192 | ||
| 193 | * GLXContext (an opaque pointer) | |
| 194 | * GLXFBConfig (an opaque pointer) | |
| 195 | * GLXPixmap (an XID) | |
| 196 | * GLXDrawable (an XID) | |
| 197 | * GLXWindow (an XID) | |
| 198 | * GLXPbuffer (an XID) | |
| 199 | ||
| 200 | To map from object to screen, record the corresponding screen when | |
| 201 | the object is created. This means the current process needs to see | |
| 202 | a GLX call to create the object. In the case of the opaque | |
| 203 | pointers, this is reasonable, since the pointer is only meaningful | |
| 204 | within the current process. | |
| 205 | ||
| 206 | XIDs, however, can be created by another process, so libGLX may not know in | |
| 207 | advance which screen they belong to. To deal with that, libGLX queries the | |
| 208 | server using the GLX extension GLX\_EXT\_libglvnd. | |
| 209 | ||
| 210 | ### EGL dispatching ### | |
| 211 | ||
| 212 | EGL dispatching works similarly to GLX, but there are fewer object types to | |
| 213 | deal with. Almost all EGL functions are dispatched based on an EGLDisplay or | |
| 214 | EGLDeviceEXT parameter. | |
| 215 | ||
| 216 | EGL can't rely on asking an X server for a vendor name like GLX can, so | |
| 217 | instead, it enumerates and loads every available vendor library. Loading every | |
| 218 | vendor is also needed to support extensions such as | |
| 219 | EGL\_EXT\_device\_enumeration. | |
| 220 | ||
| 221 | In order to find the available vendor libraries, each vendor provides a JSON | |
| 222 | file in a well-known directory, similar to how Vulkan ICD's are loaded. | |
| 223 | Please see [EGL ICD enumeration](src/EGL/icd_enumeration.md) for more details. | |
| 224 | ||
| 225 | When the application calls eglGetPlatformDisplay, EGL will simply call into | |
| 226 | each vendor library until it finds one that succeeds. After that, whichever | |
| 227 | vendor succeeded owns that display. | |
| 228 | ||
| 229 | As with GLX, vendor libraries must provide dispatch stubs for any display or | |
| 230 | device extensions that they support, so that they can add new extensions | |
| 231 | without having to modify libglvnd. | |
| 232 | ||
| 233 | Since libglvnd passes eglGetPlatformDisplay calls through to each vendor, a | |
| 234 | vendor can also add a new platform extension (e.g., EGL\_KHR\_platform\_x11) | |
| 235 | without changing libglvnd. | |
| 236 | ||
| 237 | Other EGL client extensions, by definition, do require modifying libglvnd. | |
| 238 | Those are handled on a case-by-case basis. | |
| 239 | ||
| 240 | Issues | |
| 241 | ------ | |
| 242 | ||
| 243 | * Ideally, several components of libglvnd (namely, the `libGL` wrapper library | |
| 244 | and the `libOpenGL, libGLES{v1_CM,v2}` interface libraries) could be | |
| 245 | implemented via ELF symbol filtering (see [2] for a demonstration of this). | |
| 246 | However, a loader bug (tracked in [3]) makes this mechanism unreliable: | |
| 247 | dlopen(3)ing a shared library with `DT_FILTER` fields can crash the | |
| 248 | application. Instead, for now, ELF symbol filtering is disabled by default, | |
| 249 | and an alternate approach is used to implement these libraries. | |
| 250 | ||
| 251 | * The library currently indirectly associates a drawable with a vendor, | |
| 252 | by first mapping a drawable to its screen, then mapping the screen to its | |
| 253 | vendor. However, it may make sense in render offload scenarios to allow direct | |
| 254 | mapping from drawables to vendors, so multiple vendors could potentially | |
| 255 | operate on drawables in the same screen. The problem with this is that several | |
| 256 | GLX functions, such as glXChooseFBConfig(), explicitly refer to screens, and | |
| 257 | so it becomes a gray area which vendor the call should be dispatched to. Given | |
| 258 | this issue, does it still make more sense to use a direct drawable to vendor | |
| 259 | mapping? How would this be implemented? Should we add new API calls to "GLX | |
| 260 | Next"? | |
| 261 | ||
| 262 | * Note that the (drawable -> screen -> vendor) mapping mainly exists in the | |
| 263 | GLX_EXT_libglvnd extension. libGLX itself keeps a simple | |
| 264 | (drawable -> vendor) mapping, and exposes that mapping to the vendor | |
| 265 | libraries. | |
| 266 | ||
| 267 | * Along the same lines, would it be useful to include a | |
| 268 | "glXGetProcAddressFromVendor()" or "glXGetProcAddressFromScreen()" entrypoint | |
| 269 | in a new GLX version to obviate the need for this library in future | |
| 270 | applications? | |
| 271 | ||
| 272 | * Global state is required by both libGLX.so and libGLdispatch.so for various | |
| 273 | purposes, and needs to be protected by locks in multithreaded environments. | |
| 274 | Is it reasonable for the vendor-neutral library to depend on pthreads for | |
| 275 | implementing these locks? | |
| 276 | ||
| 277 | While there is no harm in having the API libraries link against pthreads even | |
| 278 | if the application does not, we would like to avoid pthread locking overhead | |
| 279 | if the application is single-threaded. Hence, this library uses a | |
| 280 | `glvnd_pthread` wrapper library which provides single-threaded fallbacks for | |
| 281 | applications which are not linked against pthreads. It is expected that | |
| 282 | multi-threaded applications will either statically link against pthreads, or | |
| 283 | load pthreads prior to loading libGL. | |
| 284 | ||
| 285 | * Is using a hash table to store GLX extension entrypoints performant enough for | |
| 286 | dispatching? Should we be using a flat array instead? | |
| 287 | ||
| 288 | * How should malloc(3) failures be handled? | |
| 289 | ||
| 290 | * How should forking be handled? | |
| 291 | ||
| 292 | * The current libGLX implementation stores all GLXContext and GLXFBConfig | |
| 293 | handles in global hashtables, which means that GLXContext and GLXFBConfig | |
| 294 | handles must be unique between vendors. That is, two vendor libraries must | |
| 295 | not come up with the same handle value for a GLXContext or GLXFBConfig. To | |
| 296 | that end, GLXContext and GLXFBConfig handles must be pointers to memory | |
| 297 | addresses that the vendor library somehow controls. The values are otherwise | |
| 298 | opaque. | |
| 299 | ||
| 300 | * Querying an XID <=> screen mapping without somehow "locking" the XID is | |
| 301 | inherently racy, since a different process may destroy the drawable, and X | |
| 302 | may recycle the XID, after the mapping is saved client-side. Is there a mechanism | |
| 303 | we could use to notify the API library when a mapping is no longer valid? | |
| 304 | ||
| 305 | References | |
| 306 | ---------- | |
| 307 | ||
| 308 | [1] https://github.com/aritger/linux-opengl-abi-proposal/blob/master/linux-opengl-abi-proposal.txt | |
| 309 | ||
| 310 | [2] https://github.com/aritger/libgl-elf-tricks-demo | |
| 311 | ||
| 312 | [3] https://sourceware.org/bugzilla/show_bug.cgi?id=16272 | |
| 313 | ||
| 314 | Acknowledgements | |
| 315 | ------- | |
| 316 | ||
| 317 | Thanks to Andy Ritger for the original libGLX implementation and README | |
| 318 | documentation. | |
| 319 | ||
| 320 | ### libglvnd ### | |
| 321 | ||
| 322 | libglvnd itself (excluding components listed below) is licensed as follows: | |
| 323 | ||
| 324 | Copyright (c) 2013, NVIDIA CORPORATION. | |
| 325 | ||
| 326 | Permission is hereby granted, free of charge, to any person obtaining a | |
| 327 | copy of this software and/or associated documentation files (the | |
| 328 | "Materials"), to deal in the Materials without restriction, including | |
| 329 | without limitation the rights to use, copy, modify, merge, publish, | |
| 330 | distribute, sublicense, and/or sell copies of the Materials, and to | |
| 331 | permit persons to whom the Materials are furnished to do so, subject to | |
| 332 | the following conditions: | |
| 333 | ||
| 334 | The above copyright notice and this permission notice shall be included | |
| 335 | unaltered in all copies or substantial portions of the Materials. | |
| 336 | Any additions, deletions, or changes to the original source files | |
| 337 | must be clearly indicated in accompanying documentation. | |
| 338 | ||
| 339 | If only executable code is distributed, then the accompanying | |
| 340 | documentation must state that "this software is based in part on the | |
| 341 | work of the Khronos Group." | |
| 342 | ||
| 343 | THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, | |
| 344 | EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF | |
| 345 | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. | |
| 346 | IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY | |
| 347 | CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, | |
| 348 | TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE | |
| 349 | MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS. | |
| 350 | ||
| 351 | ### X.Org ### | |
| 352 | ||
| 353 | libglvnd contains list.h, a linked list implementation from the X.Org project. | |
| 354 | Source code from the X.Org project is available from: | |
| 355 | ||
| 356 | http://cgit.freedesktop.org/xorg/xserver | |
| 357 | ||
| 358 | list.h carries the following license: | |
| 359 | ||
| 360 | Copyright © 2010 Intel Corporation | |
| 361 | Copyright © 2010 Francisco Jerez <currojerez@riseup.net> | |
| 362 | ||
| 363 | Permission is hereby granted, free of charge, to any person obtaining a | |
| 364 | copy of this software and associated documentation files (the "Software"), | |
| 365 | to deal in the Software without restriction, including without limitation | |
| 366 | the rights to use, copy, modify, merge, publish, distribute, sublicense, | |
| 367 | and/or sell copies of the Software, and to permit persons to whom the | |
| 368 | Software is furnished to do so, subject to the following conditions: | |
| 369 | ||
| 370 | The above copyright notice and this permission notice (including the next | |
| 371 | paragraph) shall be included in all copies or substantial portions of the | |
| 372 | Software. | |
| 373 | ||
| 374 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| 375 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| 376 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
| 377 | THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| 378 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
| 379 | FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
| 380 | IN THE SOFTWARE. | |
| 381 | ||
| 382 | ### Mesa ### | |
| 383 | ||
| 384 | libglvnd contains code from the Mesa project. Source code from the Mesa project | |
| 385 | is available from: | |
| 386 | ||
| 387 | http://cgit.freedesktop.org/mesa/mesa | |
| 388 | ||
| 389 | The default Mesa license is as follows: | |
| 390 | ||
| 391 | Copyright (C) 1999-2007 Brian Paul All Rights Reserved. | |
| 392 | ||
| 393 | Permission is hereby granted, free of charge, to any person obtaining a | |
| 394 | copy of this software and associated documentation files (the "Software"), | |
| 395 | to deal in the Software without restriction, including without limitation | |
| 396 | the rights to use, copy, modify, merge, publish, distribute, sublicense, | |
| 397 | and/or sell copies of the Software, and to permit persons to whom the | |
| 398 | Software is furnished to do so, subject to the following conditions: | |
| 399 | ||
| 400 | The above copyright notice and this permission notice shall be included | |
| 401 | in all copies or substantial portions of the Software. | |
| 402 | ||
| 403 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS | |
| 404 | OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| 405 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
| 406 | BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN | |
| 407 | AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
| 408 | CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. | |
| 409 | ||
| 410 | ### uthash ### | |
| 411 | ||
| 412 | libglvnd uses the hash table implementation 'uthash': | |
| 413 | ||
| 414 | http://troydhanson.github.io/uthash/ | |
| 415 | ||
| 416 | This library carries the following copyright notice: | |
| 417 | ||
| 418 | Copyright (c) 2005-2013, Troy D. Hanson | |
| 419 | http://troydhanson.github.com/uthash/ | |
| 420 | All rights reserved. | |
| 421 | ||
| 422 | Redistribution and use in source and binary forms, with or without | |
| 423 | modification, are permitted provided that the following conditions are met: | |
| 424 | ||
| 425 | * Redistributions of source code must retain the above copyright | |
| 426 | notice, this list of conditions and the following disclaimer. | |
| 427 | ||
| 428 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS | |
| 429 | IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED | |
| 430 | TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A | |
| 431 | PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER | |
| 432 | OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
| 433 | EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
| 434 | PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | |
| 435 | PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF | |
| 436 | LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING | |
| 437 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS | |
| 438 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 439 | ||
| 440 | ### buildconf ### | |
| 441 | ||
| 442 | libglvnd uses the buildconf autotools bootstrapping script 'autogen.sh': | |
| 443 | ||
| 444 | http://freecode.com/projects/buildconf | |
| 445 | ||
| 446 | This script carries the following copyright notice: | |
| 447 | ||
| 448 | Copyright (c) 2005-2009 United States Government as represented by | |
| 449 | the U.S. Army Research Laboratory. | |
| 450 | ||
| 451 | Redistribution and use in source and binary forms, with or without | |
| 452 | modification, are permitted provided that the following conditions | |
| 453 | are met: | |
| 454 | ||
| 455 | 1. Redistributions of source code must retain the above copyright | |
| 456 | notice, this list of conditions and the following disclaimer. | |
| 457 | ||
| 458 | 2. Redistributions in binary form must reproduce the above | |
| 459 | copyright notice, this list of conditions and the following | |
| 460 | disclaimer in the documentation and/or other materials provided | |
| 461 | with the distribution. | |
| 462 | ||
| 463 | 3. The name of the author may not be used to endorse or promote | |
| 464 | products derived from this software without specific prior written | |
| 465 | permission. | |
| 466 | ||
| 467 | THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS | |
| 468 | OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED | |
| 469 | WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 470 | ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY | |
| 471 | DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 472 | DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE | |
| 473 | GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 474 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, | |
| 475 | WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING | |
| 476 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS | |
| 477 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 478 | ||
| 479 | ### ax-pthread ### | |
| 480 | ||
| 481 | libglvnd uses the `AX_PTHREAD` autoconf macro for detecting pthreads. | |
| 482 | The implementation of this macro carries the following license: | |
| 483 | ||
| 484 | Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu> | |
| 485 | Copyright (c) 2011 Daniel Richard G. <skunk@iSKUNK.ORG> | |
| 486 | ||
| 487 | This program is free software: you can redistribute it and/or modify it | |
| 488 | under the terms of the GNU General Public License as published by the | |
| 489 | Free Software Foundation, either version 3 of the License, or (at your | |
| 490 | option) any later version. | |
| 491 | ||
| 492 | This program is distributed in the hope that it will be useful, but | |
| 493 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 494 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General | |
| 495 | Public License for more details. | |
| 496 | ||
| 497 | You should have received a copy of the GNU General Public License along | |
| 498 | with this program. If not, see <http://www.gnu.org/licenses/>. | |
| 499 | ||
| 500 | As a special exception, the respective Autoconf Macro's copyright owner | |
| 501 | gives unlimited permission to copy, distribute and modify the configure | |
| 502 | scripts that are the output of Autoconf when processing the Macro. You | |
| 503 | need not follow the terms of the GNU General Public License when using | |
| 504 | or distributing such scripts, even though portions of the text of the | |
| 505 | Macro appear in them. The GNU General Public License (GPL) does govern | |
| 506 | all other use of the material that constitutes the Autoconf Macro. | |
| 507 | ||
| 508 | This special exception to the GPL applies to versions of the Autoconf | |
| 509 | Macro released by the Autoconf Archive. When you make and distribute a | |
| 510 | modified version of the Autoconf Macro, you may extend this special | |
| 511 | exception to the GPL to apply to your modified version as well. | |
| 512 | ||
| 513 | libglvnd uses the cJSON library for reading JSON files: | |
| 514 | ||
| 515 | https://github.com/DaveGamble/cJSON | |
| 516 | ||
| 517 | This library carries the following copyright notice: | |
| 518 | ||
| 519 | Copyright (c) 2009 Dave Gamble | |
| 520 | ||
| 521 | Permission is hereby granted, free of charge, to any person obtaining a copy | |
| 522 | of this software and associated documentation files (the "Software"), to deal | |
| 523 | in the Software without restriction, including without limitation the rights | |
| 524 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| 525 | copies of the Software, and to permit persons to whom the Software is | |
| 526 | furnished to do so, subject to the following conditions: | |
| 527 | ||
| 528 | The above copyright notice and this permission notice shall be included in | |
| 529 | all copies or substantial portions of the Software. | |
| 530 | ||
| 531 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| 532 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| 533 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| 534 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| 535 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| 536 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
| 537 | THE SOFTWARE. | |
| 538 | ||
