src/egl/main/egldriver.c

   1 /**
   2  * Functions for choosing and opening/loading device drivers.
   3  */
   4
   5
   6 #include <assert.h>
   7 #include <string.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10
  11 #include "eglstring.h"
  12 #include "egldefines.h"
  13 #include "egldisplay.h"
  14 #include "egldriver.h"
  15 #include "egllog.h"
  16 #include "eglmutex.h"
  17
  18 #if defined(_EGL_OS_UNIX)
  19 #include <dlfcn.h>
  20 #include <sys/types.h>
  21 #include <dirent.h>
  22 #include <unistd.h>
  23 #endif
  24
  25
  26 typedef struct _egl_module {
  27    char *Path;
  28    void *Handle;
  29    _EGLDriver *Driver;
  30 } _EGLModule;
  31
  32 static _EGL_DECLARE_MUTEX(_eglModuleMutex);
  33 static _EGLArray *_eglModules;
  34
  35
  36 /**
  37  * Wrappers for dlopen/dlclose()
  38  */
  39 #if defined(_EGL_OS_WINDOWS)
  40
  41
  42 typedef HMODULE lib_handle;
  43
  44 static HMODULE
  45 open_library(const char *filename)
  46 {
  47    return LoadLibrary(filename);
  48 }
  49
  50 static void
  51 close_library(HMODULE lib)
  52 {
  53    FreeLibrary(lib);
  54 }
  55
  56
  57 static const char *
  58 library_suffix(void)
  59 {
  60    return ".dll";
  61 }
  62
  63
  64 #elif defined(_EGL_OS_UNIX)
  65
  66
  67 typedef void * lib_handle;
  68
  69 static void *
  70 open_library(const char *filename)
  71 {
  72    return dlopen(filename, RTLD_LAZY);
  73 }
  74
  75 static void
  76 close_library(void *lib)
  77 {
  78    dlclose(lib);
  79 }
  80
  81
  82 static const char *
  83 library_suffix(void)
  84 {
  85    return ".so";
  86 }
  87
  88
  89 #endif
  90
  91
  92 /**
  93  * Open the named driver and find its bootstrap function: _eglMain().
  94  */
  95 static _EGLMain_t
  96 _eglOpenLibrary(const char *driverPath, lib_handle *handle)
  97 {
  98    lib_handle lib;
  99    _EGLMain_t mainFunc = NULL;
 100    const char *error = "unknown error";
 101
 102    assert(driverPath);
 103
 104    _eglLog(_EGL_DEBUG, "dlopen(%s)", driverPath);
 105    lib = open_library(driverPath);
 106
 107 #if defined(_EGL_OS_WINDOWS)
 108    /* XXX untested */
 109    if (lib)
 110       mainFunc = (_EGLMain_t) GetProcAddress(lib, "_eglMain");
 111 #elif defined(_EGL_OS_UNIX)
 112    if (lib) {
 113       union {
 114          _EGLMain_t func;
 115          void *ptr;
 116       } tmp = { NULL };
 117       /* direct cast gives a warning when compiled with -pedantic */
 118       tmp.ptr = dlsym(lib, "_eglMain");
 119       mainFunc = tmp.func;
 120       if (!mainFunc)
 121          error = dlerror();
 122    }
 123    else {
 124       error = dlerror();
 125    }
 126 #endif
 127
 128    if (!lib) {
 129       _eglLog(_EGL_WARNING, "Could not open driver %s (%s)",
 130               driverPath, error);
 131       if (!getenv("EGL_DRIVER"))
 132          _eglLog(_EGL_WARNING,
 133                  "The driver can be overridden by setting EGL_DRIVER");
 134       return NULL;
 135    }
 136
 137    if (!mainFunc) {
 138       _eglLog(_EGL_WARNING, "_eglMain not found in %s (%s)",
 139               driverPath, error);
 140       if (lib)
 141          close_library(lib);
 142       return NULL;
 143    }
 144
 145    *handle = lib;
 146    return mainFunc;
 147 }
 148
 149
 150 /**
 151  * Load a module and create the driver object.
 152  */
 153 static EGLBoolean
 154 _eglLoadModule(_EGLModule *mod)
 155 {
 156    _EGLMain_t mainFunc;
 157    lib_handle lib;
 158    _EGLDriver *drv;
 159
 160    mainFunc = _eglOpenLibrary(mod->Path, &lib);
 161    if (!mainFunc)
 162       return EGL_FALSE;
 163
 164    drv = mainFunc(NULL);
 165    if (!drv) {
 166       if (lib)
 167          close_library(lib);
 168       return EGL_FALSE;
 169    }
 170
 171    if (!drv->Name) {
 172       _eglLog(_EGL_WARNING, "Driver loaded from %s has no name", mod->Path);
 173       drv->Name = "UNNAMED";
 174    }
 175
 176    mod->Handle = (void *) lib;
 177    mod->Driver = drv;
 178
 179    return EGL_TRUE;
 180 }
 181
 182
 183 /**
 184  * Unload a module.
 185  */
 186 static void
 187 _eglUnloadModule(_EGLModule *mod)
 188 {
 189    /* destroy the driver */
 190    if (mod->Driver && mod->Driver->Unload)
 191       mod->Driver->Unload(mod->Driver);
 192    if (mod->Handle)
 193       close_library(mod->Handle);
 194
 195    mod->Driver = NULL;
 196    mod->Handle = NULL;
 197 }
 198
 199
 200 /**
 201  * Add a module to the module array.
 202  */
 203 static _EGLModule *
 204 _eglAddModule(const char *path)
 205 {
 206    _EGLModule *mod;
 207    EGLint i;
 208
 209    if (!_eglModules) {
 210       _eglModules = _eglCreateArray("Module", 8);
 211       if (!_eglModules)
 212          return NULL;
 213    }
 214
 215    /* find duplicates */
 216    for (i = 0; i < _eglModules->Size; i++) {
 217       mod = _eglModules->Elements[i];
 218       if (strcmp(mod->Path, path) == 0)
 219          return mod;
 220    }
 221
 222    /* allocate a new one */
 223    mod = calloc(1, sizeof(*mod));
 224    if (mod) {
 225       mod->Path = _eglstrdup(path);
 226       if (!mod->Path) {
 227          free(mod);
 228          mod = NULL;
 229       }
 230    }
 231    if (mod) {
 232       _eglAppendArray(_eglModules, (void *) mod);
 233       _eglLog(_EGL_DEBUG, "added %s to module array", mod->Path);
 234    }
 235
 236    return mod;
 237 }
 238
 239
 240 /**
 241  * Free a module.
 242  */
 243 static void
 244 _eglFreeModule(void *module)
 245 {
 246    _EGLModule *mod = (_EGLModule *) module;
 247
 248    _eglUnloadModule(mod);
 249    free(mod->Path);
 250    free(mod);
 251 }
 252
 253
 254 /**
 255  * A loader function for use with _eglPreloadForEach.  The loader data is the
 256  * filename of the driver.   This function stops on the first valid driver.
 257  */
 258 static EGLBoolean
 259 _eglLoaderFile(const char *dir, size_t len, void *loader_data)
 260 {
 261    char path[1024];
 262    const char *filename = (const char *) loader_data;
 263    size_t flen = strlen(filename);
 264
 265    /* make a full path */
 266    if (len + flen + 2 > sizeof(path))
 267       return EGL_TRUE;
 268    if (len) {
 269       memcpy(path, dir, len);
 270       path[len++] = '/';
 271    }
 272    memcpy(path + len, filename, flen);
 273    len += flen;
 274    path[len] = '\0';
 275
 276    if (library_suffix()) {
 277       const char *suffix = library_suffix();
 278       size_t slen = strlen(suffix);
 279       const char *p;
 280       EGLBoolean need_suffix;
 281
 282       p = filename + flen - slen;
 283       need_suffix = (p < filename || strcmp(p, suffix) != 0);
 284       if (need_suffix) {
 285          /* overflow */
 286          if (len + slen + 1 > sizeof(path))
 287             return EGL_TRUE;
 288          strcpy(path + len, suffix);
 289       }
 290    }
 291
 292 #if defined(_EGL_OS_UNIX)
 293    /* check if the file exists */
 294    if (access(path, F_OK))
 295       return EGL_TRUE;
 296 #endif
 297
 298    _eglAddModule(path);
 299
 300    return EGL_TRUE;
 301 }
 302
 303
 304 /**
 305  * A loader function for use with _eglPreloadForEach.  The loader data is the
 306  * pattern (prefix) of the files to look for.
 307  */
 308 static EGLBoolean
 309 _eglLoaderPattern(const char *dir, size_t len, void *loader_data)
 310 {
 311 #if defined(_EGL_OS_UNIX)
 312    const char *prefix, *suffix;
 313    size_t prefix_len, suffix_len;
 314    DIR *dirp;
 315    struct dirent *dirent;
 316    char path[1024];
 317
 318    if (len + 2 > sizeof(path))
 319       return EGL_TRUE;
 320    if (len) {
 321       memcpy(path, dir, len);
 322       path[len++] = '/';
 323    }
 324    path[len] = '\0';
 325
 326    dirp = opendir(path);
 327    if (!dirp)
 328       return EGL_TRUE;
 329
 330    prefix = (const char *) loader_data;
 331    prefix_len = strlen(prefix);
 332    suffix = library_suffix();
 333    suffix_len = (suffix) ? strlen(suffix) : 0;
 334
 335    while ((dirent = readdir(dirp))) {
 336       size_t dirent_len = strlen(dirent->d_name);
 337       const char *p;
 338
 339       /* match the prefix */
 340       if (strncmp(dirent->d_name, prefix, prefix_len) != 0)
 341          continue;
 342       /* match the suffix */
 343       if (suffix) {
 344          p = dirent->d_name + dirent_len - suffix_len;
 345          if (p < dirent->d_name || strcmp(p, suffix) != 0)
 346             continue;
 347       }
 348
 349       /* make a full path and add it to the module array */
 350       if (len + dirent_len + 1 <= sizeof(path)) {
 351          strcpy(path + len, dirent->d_name);
 352          _eglAddModule(path);
 353       }
 354    }
 355
 356    closedir(dirp);
 357
 358    return EGL_TRUE;
 359 #else /* _EGL_OS_UNIX */
 360    /* stop immediately */
 361    return EGL_FALSE;
 362 #endif
 363 }
 364
 365
 366 /**
 367  * Run the callback function on each driver directory.
 368  *
 369  * The process may end prematurely if the callback function returns false.
 370  */
 371 static void
 372 _eglPreloadForEach(const char *search_path,
 373                    EGLBoolean (*loader)(const char *, size_t, void *),
 374                    void *loader_data)
 375 {
 376    const char *cur, *next;
 377    size_t len;
 378
 379    cur = search_path;
 380    while (cur) {
 381       next = strchr(cur, ':');
 382       len = (next) ? next - cur : strlen(cur);
 383
 384       if (!loader(cur, len, loader_data))
 385          break;
 386
 387       cur = (next) ? next + 1 : NULL;
 388    }
 389 }
 390
 391
 392 /**
 393  * Return a list of colon-separated driver directories.
 394  */
 395 static const char *
 396 _eglGetSearchPath(void)
 397 {
 398    static char search_path[1024];
 399
 400 #if defined(_EGL_OS_UNIX) || defined(_EGL_OS_WINDOWS)
 401    if (search_path[0] == '\0') {
 402       char *buf = search_path;
 403       size_t len = sizeof(search_path);
 404       EGLBoolean use_env;
 405       char dir_sep;
 406       int ret;
 407
 408 #if defined(_EGL_OS_UNIX)
 409       use_env = (geteuid() == getuid() && getegid() == getgid());
 410       dir_sep = '/';
 411 #else
 412       use_env = EGL_TRUE;
 413       dir_sep = '\\';
 414 #endif
 415
 416       if (use_env) {
 417          char *p;
 418
 419          /* extract the dirname from EGL_DRIVER */
 420          p = getenv("EGL_DRIVER");
 421          if (p && strchr(p, dir_sep)) {
 422             ret = _eglsnprintf(buf, len, "%s", p);
 423             if (ret > 0 && ret < len) {
 424                p = strrchr(buf, dir_sep);
 425                *p++ = ':';
 426
 427                len -= p - buf;
 428                buf = p;
 429             }
 430          }
 431
 432          /* append EGL_DRIVERS_PATH */
 433          p = getenv("EGL_DRIVERS_PATH");
 434          if (p) {
 435             ret = _eglsnprintf(buf, len, "%s:", p);
 436             if (ret > 0 && ret < len) {
 437                buf += ret;
 438                len -= ret;
 439             }
 440          }
 441       }
 442       else {
 443          _eglLog(_EGL_DEBUG,
 444                "ignore EGL_DRIVERS_PATH for setuid/setgid binaries");
 445       }
 446
 447       ret = _eglsnprintf(buf, len, "%s", _EGL_DRIVER_SEARCH_DIR);
 448       if (ret < 0 || ret >= len)
 449          search_path[0] = '\0';
 450
 451       _eglLog(_EGL_DEBUG, "EGL search path is %s", search_path);
 452    }
 453 #endif /* defined(_EGL_OS_UNIX) || defined(_EGL_OS_WINDOWS) */
 454
 455    return search_path;
 456 }
 457
 458
 459 /**
 460  * Add the user driver to the module array.
 461  *
 462  * The user driver is specified by EGL_DRIVER.
 463  */
 464 static void
 465 _eglAddUserDriver(void)
 466 {
 467    const char *search_path = _eglGetSearchPath();
 468    char *env;
 469
 470    env = getenv("EGL_DRIVER");
 471 #if defined(_EGL_OS_UNIX)
 472    if (env && strchr(env, '/')) {
 473       search_path = "";
 474       if ((geteuid() != getuid() || getegid() != getgid())) {
 475          _eglLog(_EGL_DEBUG,
 476                "ignore EGL_DRIVER for setuid/setgid binaries");
 477          env = NULL;
 478       }
 479    }
 480 #endif /* _EGL_OS_UNIX */
 481    if (env)
 482       _eglPreloadForEach(search_path, _eglLoaderFile, (void *) env);
 483 }
 484
 485
 486 /**
 487  * Add default drivers to the module array.
 488  */
 489 static void
 490 _eglAddDefaultDrivers(void)
 491 {
 492    const char *search_path = _eglGetSearchPath();
 493    EGLint i;
 494 #if defined(_EGL_OS_WINDOWS)
 495    const char *DefaultDriverNames[] = {
 496       "egl_gallium"
 497    };
 498 #elif defined(_EGL_OS_UNIX)
 499    const char *DefaultDriverNames[] = {
 500       "egl_gallium",
 501       "egl_dri2",
 502       "egl_glx"
 503    };
 504 #endif
 505
 506    for (i = 0; i < ARRAY_SIZE(DefaultDriverNames); i++) {
 507       void *name = (void *) DefaultDriverNames[i];
 508       _eglPreloadForEach(search_path, _eglLoaderFile, name);
 509    }
 510 }
 511
 512
 513 /**
 514  * Add drivers to the module array.  Drivers will be loaded as they are matched
 515  * to displays.
 516  */
 517 static EGLBoolean
 518 _eglAddDrivers(void)
 519 {
 520    if (_eglModules)
 521       return EGL_TRUE;
 522
 523    /* the order here decides the priorities of the drivers */
 524    _eglAddUserDriver();
 525    _eglAddDefaultDrivers();
 526    _eglPreloadForEach(_eglGetSearchPath(), _eglLoaderPattern, (void *) "egl_");
 527
 528    return (_eglModules != NULL);
 529 }
 530
 531
 532 /**
 533  * Match a display to a driver.  The display is initialized unless use_probe is
 534  * true.
 535  *
 536  * The matching is done by finding the first driver that can initialize the
 537  * display, or when use_probe is true, the driver with highest score.
 538  */
 539 _EGLDriver *
 540 _eglMatchDriver(_EGLDisplay *dpy, EGLBoolean use_probe)
 541 {
 542    _EGLModule *mod;
 543    _EGLDriver *best_drv = NULL;
 544    EGLint best_score = 0;
 545    EGLint major, minor, i;
 546
 547    _eglLockMutex(&_eglModuleMutex);
 548
 549    if (!_eglAddDrivers()) {
 550       _eglUnlockMutex(&_eglModuleMutex);
 551       return EGL_FALSE;
 552    }
 553
 554    /* match the loaded modules */
 555    for (i = 0; i < _eglModules->Size; i++) {
 556       mod = (_EGLModule *) _eglModules->Elements[i];
 557       if (!mod->Driver)
 558          break;
 559
 560       if (use_probe) {
 561          EGLint score = (mod->Driver->Probe) ?
 562             mod->Driver->Probe(mod->Driver, dpy) : 1;
 563          if (score > best_score) {
 564             best_drv = mod->Driver;
 565             best_score = score;
 566          }
 567       }
 568       else {
 569          if (mod->Driver->API.Initialize(mod->Driver, dpy, &major, &minor)) {
 570             best_drv = mod->Driver;
 571             best_score = 100;
 572          }
 573       }
 574       /* perfect match */
 575       if (best_score >= 100)
 576          break;
 577    }
 578
 579    /* load more modules */
 580    if (!best_drv) {
 581       EGLint first_unloaded = i;
 582
 583       while (i < _eglModules->Size) {
 584          mod = (_EGLModule *) _eglModules->Elements[i];
 585          assert(!mod->Driver);
 586
 587          if (!_eglLoadModule(mod)) {
 588             /* remove invalid modules */
 589             _eglEraseArray(_eglModules, i, _eglFreeModule);
 590             continue;
 591          }
 592
 593          if (use_probe) {
 594             best_score = (mod->Driver->Probe) ?
 595                mod->Driver->Probe(mod->Driver, dpy) : 1;
 596          }
 597          else {
 598             if (mod->Driver->API.Initialize(mod->Driver, dpy, &major, &minor))
 599                best_score = 100;
 600          }
 601
 602          if (best_score > 0) {
 603             best_drv = mod->Driver;
 604             /* loaded modules come before unloaded ones */
 605             if (first_unloaded != i) {
 606                void *tmp = _eglModules->Elements[i];
 607                _eglModules->Elements[i] =
 608                   _eglModules->Elements[first_unloaded];
 609                _eglModules->Elements[first_unloaded] = tmp;
 610             }
 611             break;
 612          }
 613          else {
 614             _eglUnloadModule(mod);
 615             i++;
 616          }
 617       }
 618    }
 619
 620    _eglUnlockMutex(&_eglModuleMutex);
 621
 622    if (best_drv) {
 623       _eglLog(_EGL_DEBUG, "the best driver is %s (score %d)",
 624             best_drv->Name, best_score);
 625       if (!use_probe) {
 626          dpy->Driver = best_drv;
 627          dpy->Initialized = EGL_TRUE;
 628          dpy->APImajor = major;
 629          dpy->APIminor = minor;
 630       }
 631    }
 632
 633    return best_drv;
 634 }
 635
 636
 637 __eglMustCastToProperFunctionPointerType
 638 _eglGetDriverProc(const char *procname)
 639 {
 640    EGLint i;
 641    _EGLProc proc = NULL;
 642
 643    if (!_eglModules) {
 644       /* load the driver for the default display */
 645       EGLDisplay egldpy = eglGetDisplay(EGL_DEFAULT_DISPLAY);
 646       _EGLDisplay *dpy = _eglLookupDisplay(egldpy);
 647       if (!dpy || !_eglMatchDriver(dpy, EGL_TRUE))
 648          return NULL;
 649    }
 650
 651    for (i = 0; i < _eglModules->Size; i++) {
 652       _EGLModule *mod = (_EGLModule *) _eglModules->Elements[i];
 653
 654       if (!mod->Driver)
 655          break;
 656       proc = mod->Driver->API.GetProcAddress(mod->Driver, procname);
 657       if (proc)
 658          break;
 659    }
 660
 661    return proc;
 662 }
 663
 664
 665 /**
 666  * Unload all drivers.
 667  */
 668 void
 669 _eglUnloadDrivers(void)
 670 {
 671    /* this is called at atexit time */
 672    if (_eglModules) {
 673 #if defined(_EGL_OS_UNIX)
 674       _eglDestroyArray(_eglModules, _eglFreeModule);
 675 #elif defined(_EGL_OS_WINDOWS)
 676       /* XXX Windows unloads DLLs before atexit */
 677       _eglDestroyArray(_eglModules, NULL);
 678 #endif
 679       _eglModules = NULL;
 680    }
 681 }
 682
 683
 684 /**
 685  * Invoke a callback function on each EGL search path.
 686  *
 687  * The first argument of the callback function is the name of the search path.
 688  * The second argument is the length of the name.
 689  */
 690 void
 691 _eglSearchPathForEach(EGLBoolean (*callback)(const char *, size_t, void *),
 692                       void *callback_data)
 693 {
 694    const char *search_path = _eglGetSearchPath();
 695    _eglPreloadForEach(search_path, callback, callback_data);
 696 }