/*
 ** Copyright 2007, The Android Open Source Project
 **
 ** Licensed under the Apache License, Version 2.0 (the "License");
 ** you may not use this file except in compliance with the License.
 ** You may obtain a copy of the License at
 **
 **     http://www.apache.org/licenses/LICENSE-2.0
 **
 ** Unless required by applicable law or agreed to in writing, software
 ** distributed under the License is distributed on an "AS IS" BASIS,
 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 ** See the License for the specific language governing permissions and
 ** limitations under the License.
 */

//#define LOG_NDEBUG 0
#define ATRACE_TAG ATRACE_TAG_GRAPHICS

#include "EGL/Loader.h"

#include <android-base/properties.h>
#include <android/dlext.h>
#include <cutils/properties.h>
#include <dirent.h>
#include <dlfcn.h>
#include <graphicsenv/GraphicsEnv.h>
#include <log/log.h>
#include <utils/Timers.h>
#include <vndksupport/linker.h>

#include <string>

#include "EGL/eglext_angle.h"
#include "egl_platform_entries.h"
#include "egl_trace.h"
#include "egldefs.h"

namespace android {

/*
 * EGL userspace drivers must be provided either:
 * - as a single library:
 *      /vendor/${LIB}/egl/libGLES.so
 *
 * - as separate libraries:
 *      /vendor/${LIB}/egl/libEGL.so
 *      /vendor/${LIB}/egl/libGLESv1_CM.so
 *      /vendor/${LIB}/egl/libGLESv2.so
 *
 * For backward compatibility and to facilitate the transition to
 * this new naming scheme, the loader will additionally look for:
 *
 *      /vendor/${LIB}/egl/lib{GLES | [EGL|GLESv1_CM|GLESv2]}_${SUFFIX}.so
 *
 */

#ifndef SYSTEM_LIB_PATH
#if defined(__LP64__)
#define SYSTEM_LIB_PATH "/system/lib64"
#else
#define SYSTEM_LIB_PATH "/system/lib"
#endif
#endif

static const char* PERSIST_DRIVER_SUFFIX_PROPERTY = "persist.graphics.egl";
static const char* RO_DRIVER_SUFFIX_PROPERTY = "ro.hardware.egl";
static const char* RO_BOARD_PLATFORM_PROPERTY = "ro.board.platform";
static const char* ANGLE_SUFFIX_VALUE = "angle";

static const char* HAL_SUBNAME_KEY_PROPERTIES[3] = {
        PERSIST_DRIVER_SUFFIX_PROPERTY,
        RO_DRIVER_SUFFIX_PROPERTY,
        RO_BOARD_PLATFORM_PROPERTY,
};

static const char* const VENDOR_LIB_EGL_DIR =
#if defined(__LP64__)
        "/vendor/lib64/egl";
#else
        "/vendor/lib/egl";
#endif

static const char* const SYSTEM_LIB_DIR =
#if defined(__LP64__)
        "/system/lib64";
#else
        "/system/lib";
#endif

static void* do_dlopen(const char* path, int mode) {
    ATRACE_CALL();
    return dlopen(path, mode);
}

static void* do_android_dlopen_ext(const char* path, int mode, const android_dlextinfo* info) {
    ATRACE_CALL();
    return android_dlopen_ext(path, mode, info);
}

static void* do_android_load_sphal_library(const char* path, int mode) {
    ATRACE_CALL();
    return android_load_sphal_library(path, mode);
}

static int do_android_unload_sphal_library(void* dso) {
    ATRACE_CALL();
    return android_unload_sphal_library(dso);
}

static void* load_wrapper(const char* path) {
    void* so = do_dlopen(path, RTLD_NOW | RTLD_LOCAL);
    ALOGE_IF(!so, "dlopen(\"%s\") failed: %s", path, dlerror());
    return so;
}

Loader& Loader::getInstance() {
    static Loader loader;
    return loader;
}

Loader::driver_t::driver_t(void* gles)
{
    dso[0] = gles;
    for (size_t i=1 ; i<NELEM(dso) ; i++)
        dso[i] = nullptr;
}

Loader::driver_t::~driver_t()
{
    for (size_t i=0 ; i<NELEM(dso) ; i++) {
        if (dso[i]) {
            dlclose(dso[i]);
            dso[i] = nullptr;
        }
    }
}

int Loader::driver_t::set(void* hnd, int32_t api)
{
    switch (api) {
        case EGL:
            dso[0] = hnd;
            break;
        case GLESv1_CM:
            dso[1] = hnd;
            break;
        case GLESv2:
            dso[2] = hnd;
            break;
        default:
            return -EOVERFLOW;
    }
    return 0;
}

Loader::Loader()
    : getProcAddress(nullptr)
{
}

Loader::~Loader() {
}

// Check whether the loaded system drivers should be unloaded in order to
// load ANGLE or the updatable graphics drivers.
// If ANGLE namespace is set, it means the application is identified to run on top of ANGLE.
// If updatable graphics driver namespace is set, it means the application is identified to
// run on top of updatable graphics drivers.
static bool should_unload_system_driver(egl_connection_t* cnx) {
    // Return false if the system driver has been unloaded once.
    if (cnx->systemDriverUnloaded) {
        return false;
    }

    // Return true if ANGLE namespace is set.
    android_namespace_t* ns = android::GraphicsEnv::getInstance().getAngleNamespace();
    if (ns) {
        // Unless the default GLES driver is ANGLE and the process should use system ANGLE, since
        // the intended GLES driver is already loaded.
        // This should be updated in a later patch that cleans up namespaces
        if (!(cnx->angleLoaded && android::GraphicsEnv::getInstance().shouldUseSystemAngle())) {
            return true;
        }
    }

    // Return true if app requests to use ANGLE, but ANGLE is not loaded.
    // Difference with the case above is on devices that don't have an ANGLE apk installed,
    // ANGLE namespace is not set. In that case if ANGLE in system partition is not loaded,
    // we should unload the system driver first, and then load ANGLE from system partition.
    if (!cnx->angleLoaded && android::GraphicsEnv::getInstance().shouldUseAngle()) {
        return true;
    }

    // Return true if native GLES drivers should be used and ANGLE is already loaded.
    if (android::GraphicsEnv::getInstance().shouldUseNativeDriver() && cnx->angleLoaded) {
        return true;
    }

    // Return true if updated driver namespace is set.
    ns = android::GraphicsEnv::getInstance().getDriverNamespace();
    if (ns) {
        return true;
    }

    return false;
}

static void uninit_api(char const* const* api, __eglMustCastToProperFunctionPointerType* curr) {
    while (*api) {
        *curr++ = nullptr;
        api++;
    }
}

void Loader::unload_system_driver(egl_connection_t* cnx) {
    ATRACE_CALL();

    uninit_api(gl_names,
               (__eglMustCastToProperFunctionPointerType*)&cnx
                       ->hooks[egl_connection_t::GLESv2_INDEX]
                       ->gl);
    uninit_api(gl_names,
               (__eglMustCastToProperFunctionPointerType*)&cnx
                       ->hooks[egl_connection_t::GLESv1_INDEX]
                       ->gl);
    uninit_api(egl_names, (__eglMustCastToProperFunctionPointerType*)&cnx->egl);

    if (cnx->dso) {
        ALOGD("Unload system gl driver.");
        driver_t* hnd = (driver_t*)cnx->dso;
        if (hnd->dso[2]) {
            do_android_unload_sphal_library(hnd->dso[2]);
        }
        if (hnd->dso[1]) {
            do_android_unload_sphal_library(hnd->dso[1]);
        }
        if (hnd->dso[0]) {
            do_android_unload_sphal_library(hnd->dso[0]);
        }
        cnx->dso = nullptr;
        cnx->angleLoaded = false;
    }

    cnx->systemDriverUnloaded = true;
}

void* Loader::open(egl_connection_t* cnx) {
    ATRACE_CALL();
    const nsecs_t openTime = systemTime();

    if (cnx->dso && should_unload_system_driver(cnx)) {
        unload_system_driver(cnx);
    }

    // If a driver has been loaded, return the driver directly.
    if (cnx->dso) {
        return cnx->dso;
    }

    driver_t* hnd = nullptr;
    // Firstly, try to load ANGLE driver, if ANGLE should be loaded and fail, abort.
    if (android::GraphicsEnv::getInstance().shouldUseAngle()) {
        hnd = attempt_to_load_angle(cnx);
        LOG_ALWAYS_FATAL_IF(!hnd, "Failed to load ANGLE.");
    }

    if (!hnd) {
        // Secondly, try to load from driver apk.
        hnd = attempt_to_load_updated_driver(cnx);

        // If updated driver apk is set but fail to load, abort here.
        LOG_ALWAYS_FATAL_IF(android::GraphicsEnv::getInstance().getDriverNamespace() && !hnd,
                            "couldn't find an OpenGL ES implementation from %s",
                            android::GraphicsEnv::getInstance().getDriverPath().c_str());
    }

    // Attempt to load native GLES drivers specified by ro.hardware.egl if native is selected.
    // If native is selected but fail to load, abort.
    if (!hnd && android::GraphicsEnv::getInstance().shouldUseNativeDriver()) {
        auto driverSuffix = base::GetProperty(RO_DRIVER_SUFFIX_PROPERTY, "");
        LOG_ALWAYS_FATAL_IF(driverSuffix.empty(),
                            "Native GLES driver is selected but not specified in %s",
                            RO_DRIVER_SUFFIX_PROPERTY);
        hnd = attempt_to_load_system_driver(cnx, driverSuffix.c_str(), true);
        LOG_ALWAYS_FATAL_IF(!hnd, "Native GLES driver is selected but failed to load. %s=%s",
                            RO_DRIVER_SUFFIX_PROPERTY, driverSuffix.c_str());
    }

    // Finally, try to load default driver.
    bool failToLoadFromDriverSuffixProperty = false;
    if (!hnd) {
        // Start by searching for the library name appended by the system
        // properties of the GLES userspace driver in both locations.
        // i.e.:
        //      libGLES_${prop}.so, or:
        //      libEGL_${prop}.so, libGLESv1_CM_${prop}.so, libGLESv2_${prop}.so
        for (auto key : HAL_SUBNAME_KEY_PROPERTIES) {
            auto prop = base::GetProperty(key, "");
            if (prop.empty()) {
                continue;
            }
            hnd = attempt_to_load_system_driver(cnx, prop.c_str(), true);
            if (!hnd) {
                ALOGD("Failed to load drivers from property %s with value %s", key, prop.c_str());
                failToLoadFromDriverSuffixProperty = true;
            }

            // Abort regardless of whether subsequent properties are set, the value must be set
            // correctly with the first property that has a value.
            break;
        }
    }

    if (!hnd) {
        // Can't find graphics driver by appending the value from system properties, now search for
        // the exact name without any suffix of the GLES userspace driver in both locations.
        // i.e.:
        //      libGLES.so, or:
        //      libEGL.so, libGLESv1_CM.so, libGLESv2.so
        hnd = attempt_to_load_system_driver(cnx, nullptr, true);
    }

    if (!hnd && !failToLoadFromDriverSuffixProperty &&
        property_get_int32("ro.vendor.api_level", 0) < __ANDROID_API_U__) {
        // Still can't find the graphics drivers with the exact name. This time try to use wildcard
        // matching if the device is launched before Android 14.
        hnd = attempt_to_load_system_driver(cnx, nullptr, false);
    }

    if (!hnd) {
        android::GraphicsEnv::getInstance().setDriverLoaded(android::GpuStatsInfo::Api::API_GL,
                                                            false, systemTime() - openTime);
    } else {
        // init_angle_backend will check if loaded driver is ANGLE or not,
        // will set cnx->angleLoaded appropriately.
        // Do this here so that we use ANGLE path when driver is ANGLE (e.g. loaded as native),
        // not just loading ANGLE as option.
        attempt_to_init_angle_backend(hnd->dso[2], cnx);
    }

    LOG_ALWAYS_FATAL_IF(!hnd,
                        "couldn't find an OpenGL ES implementation, make sure one of %s, %s and %s "
                        "is set",
                        HAL_SUBNAME_KEY_PROPERTIES[0], HAL_SUBNAME_KEY_PROPERTIES[1],
                        HAL_SUBNAME_KEY_PROPERTIES[2]);

    if (!cnx->libEgl) {
        cnx->libEgl = load_wrapper(SYSTEM_LIB_PATH "/libEGL.so");
    }
    if (!cnx->libGles1) {
        cnx->libGles1 = load_wrapper(SYSTEM_LIB_PATH "/libGLESv1_CM.so");
    }
    if (!cnx->libGles2) {
        cnx->libGles2 = load_wrapper(SYSTEM_LIB_PATH "/libGLESv2.so");
    }

    if (!cnx->libEgl || !cnx->libGles2 || !cnx->libGles1) {
        android::GraphicsEnv::getInstance().setDriverLoaded(android::GpuStatsInfo::Api::API_GL,
                                                            false, systemTime() - openTime);
    }

    LOG_ALWAYS_FATAL_IF(!cnx->libEgl,
            "couldn't load system EGL wrapper libraries");

    LOG_ALWAYS_FATAL_IF(!cnx->libGles2 || !cnx->libGles1,
                        "couldn't load system OpenGL ES wrapper libraries");

    android::GraphicsEnv::getInstance().setDriverLoaded(android::GpuStatsInfo::Api::API_GL, true,
                                                        systemTime() - openTime);

    return (void*)hnd;
}

void Loader::close(egl_connection_t* cnx)
{
    driver_t* hnd = (driver_t*) cnx->dso;
    delete hnd;
    cnx->dso = nullptr;

    cnx->angleLoaded = false;
}

void Loader::init_api(void* dso,
        char const * const * api,
        char const * const * ref_api,
        __eglMustCastToProperFunctionPointerType* curr,
        getProcAddressType getProcAddress)
{
    ATRACE_CALL();

    const ssize_t SIZE = 256;
    char scrap[SIZE];
    while (*api) {
        char const * name = *api;
        if (ref_api) {
            char const * ref_name = *ref_api;
            if (std::strcmp(name, ref_name) != 0) {
                *curr++ = nullptr;
                ref_api++;
                continue;
            }
        }

        __eglMustCastToProperFunctionPointerType f =
            (__eglMustCastToProperFunctionPointerType)dlsym(dso, name);
        if (f == nullptr) {
            // couldn't find the entry-point, use eglGetProcAddress()
            f = getProcAddress(name);
        }
        if (f == nullptr) {
            // Try without the OES postfix
            ssize_t index = ssize_t(strlen(name)) - 3;
            if ((index>0 && (index<SIZE-1)) && (!strcmp(name+index, "OES"))) {
                strncpy(scrap, name, index);
                scrap[index] = 0;
                f = (__eglMustCastToProperFunctionPointerType)dlsym(dso, scrap);
                //ALOGD_IF(f, "found <%s> instead", scrap);
            }
        }
        if (f == nullptr) {
            // Try with the OES postfix
            ssize_t index = ssize_t(strlen(name)) - 3;
            if (index>0 && strcmp(name+index, "OES")) {
                snprintf(scrap, SIZE, "%sOES", name);
                f = (__eglMustCastToProperFunctionPointerType)dlsym(dso, scrap);
                //ALOGD_IF(f, "found <%s> instead", scrap);
            }
        }
        if (f == nullptr) {
            //ALOGD("%s", name);
            f = (__eglMustCastToProperFunctionPointerType)gl_unimplemented;

            /*
             * GL_EXT_debug_marker is special, we always report it as
             * supported, it's handled by GLES_trace. If GLES_trace is not
             * enabled, then these are no-ops.
             */
            if (!strcmp(name, "glInsertEventMarkerEXT")) {
                f = (__eglMustCastToProperFunctionPointerType)gl_noop;
            } else if (!strcmp(name, "glPushGroupMarkerEXT")) {
                f = (__eglMustCastToProperFunctionPointerType)gl_noop;
            } else if (!strcmp(name, "glPopGroupMarkerEXT")) {
                f = (__eglMustCastToProperFunctionPointerType)gl_noop;
            }
        }
        *curr++ = f;
        api++;
        if (ref_api) ref_api++;
    }
}

static std::string findLibrary(const std::string libraryName, const std::string searchPath,
                               const bool exact) {
    if (exact) {
        std::string absolutePath = searchPath + "/" + libraryName + ".so";
        if (!access(absolutePath.c_str(), R_OK)) {
            return absolutePath;
        }
        return std::string();
    }

    DIR* d = opendir(searchPath.c_str());
    if (d != nullptr) {
        struct dirent* e;
        while ((e = readdir(d)) != nullptr) {
            if (e->d_type == DT_DIR) {
                continue;
            }
            if (!strcmp(e->d_name, "libGLES_android.so")) {
                // always skip the software renderer
                continue;
            }
            if (strstr(e->d_name, libraryName.c_str()) == e->d_name) {
                if (!strcmp(e->d_name + strlen(e->d_name) - 3, ".so")) {
                    std::string result = searchPath + "/" + e->d_name;
                    closedir(d);
                    return result;
                }
            }
        }
        closedir(d);
    }
    // Driver not found. gah.
    return std::string();
}

static void* load_system_driver(const char* kind, const char* suffix, const bool exact) {
    ATRACE_CALL();

    std::string libraryName = std::string("lib") + kind;
    if (suffix) {
        libraryName += std::string("_") + suffix;
    } else if (!exact) {
        // Deprecated for devices launching in Android 14
        // Look for files that match
        //      libGLES_*.so, or,
        //      libEGL_*.so, libGLESv1_CM_*.so, libGLESv2_*.so
        libraryName += std::string("_");
    }

    void* dso = nullptr;

    const bool isSuffixAngle = suffix != nullptr && strcmp(suffix, ANGLE_SUFFIX_VALUE) == 0;
    const std::string absolutePath =
            findLibrary(libraryName, isSuffixAngle ? SYSTEM_LIB_PATH : VENDOR_LIB_EGL_DIR, exact);
    if (absolutePath.empty()) {
        // this happens often, we don't want to log an error
        return nullptr;
    }
    const char* const driverAbsolutePath = absolutePath.c_str();

    // Currently the default driver is unlikely to be ANGLE on most devices,
    // hence put this first. Only use sphal namespace when system ANGLE binaries
    // are not the default drivers.
    if (!isSuffixAngle) {
        // Try to load drivers from the 'sphal' namespace, if it exist. Fall back to
        // the original routine when the namespace does not exist.
        // See /system/linkerconfig/contents/namespace for the configuration of the
        // sphal namespace.
        dso = do_android_load_sphal_library(driverAbsolutePath, RTLD_NOW | RTLD_LOCAL);
    } else {
        // Try to load drivers from the default namespace.
        // See /system/linkerconfig/contents/namespace for the configuration of the
        // default namespace.
        dso = do_dlopen(driverAbsolutePath, RTLD_NOW | RTLD_LOCAL);
    }

    if (dso == nullptr) {
        const char* err = dlerror();
        ALOGE("load_driver(%s): %s", driverAbsolutePath, err ? err : "unknown");
        return nullptr;
    }

    ALOGV("loaded %s", driverAbsolutePath);

    return dso;
}

static void* load_angle(const char* kind, android_namespace_t* ns) {
    std::string name = std::string("lib") + kind + "_angle.so";
    void* so = nullptr;

    if (android::GraphicsEnv::getInstance().shouldUseSystemAngle()) {
        so = do_dlopen(name.c_str(), RTLD_NOW | RTLD_LOCAL);
    } else {
        const android_dlextinfo dlextinfo = {
                .flags = ANDROID_DLEXT_USE_NAMESPACE,
                .library_namespace = ns,
        };
        auto prop = base::GetProperty("debug.angle.libs.suffix", "");
        if (!prop.empty()) {
            name = std::string("lib") + kind + "_" + prop + ".so";
        }
        so = do_android_dlopen_ext(name.c_str(), RTLD_LOCAL | RTLD_NOW, &dlextinfo);
    }

    if (so) {
        return so;
    } else {
        ALOGE("dlopen_ext(\"%s\") failed: %s", name.c_str(), dlerror());
    }

    return nullptr;
}

static void* load_updated_driver(const char* kind, android_namespace_t* ns) {
    ATRACE_CALL();
    const android_dlextinfo dlextinfo = {
        .flags = ANDROID_DLEXT_USE_NAMESPACE,
        .library_namespace = ns,
    };
    void* so = nullptr;
    for (auto key : HAL_SUBNAME_KEY_PROPERTIES) {
        auto prop = base::GetProperty(key, "");
        if (prop.empty()) {
            continue;
        }
        std::string name = std::string("lib") + kind + "_" + prop + ".so";
        so = do_android_dlopen_ext(name.c_str(), RTLD_LOCAL | RTLD_NOW, &dlextinfo);
        if (so) {
            return so;
        }
        ALOGE("Could not load %s from updatable gfx driver namespace: %s.", name.c_str(),
              dlerror());
    }
    return nullptr;
}

Loader::driver_t* Loader::attempt_to_load_angle(egl_connection_t* cnx) {
    ATRACE_CALL();

    android_namespace_t* ns = android::GraphicsEnv::getInstance().getAngleNamespace();
    // ANGLE namespace is used for loading ANGLE from apk, and hence if namespace is not
    // constructed, it means ANGLE apk is not set to be the OpenGL ES driver.
    // Hence skip if ANGLE apk and system ANGLE are not set to be the OpenGL ES driver.
    if (!ns && !android::GraphicsEnv::getInstance().shouldUseSystemAngle()) {
        return nullptr;
    }

    // use ANGLE APK driver
    android::GraphicsEnv::getInstance().setDriverToLoad(android::GpuStatsInfo::Driver::ANGLE);
    driver_t* hnd = nullptr;

    // ANGLE doesn't ship with GLES library, and thus we skip GLES driver.
    // b/370113081: if there is no libEGL_angle.so in namespace ns, libEGL_angle.so in system
    // partition will be loaded instead. If there is no libEGL_angle.so in system partition, no
    // angle libs are loaded, and app that sets to use ANGLE will crash.
    void* dso = load_angle("EGL", ns);
    if (dso) {
        initialize_api(dso, cnx, EGL);
        hnd = new driver_t(dso);

        dso = load_angle("GLESv1_CM", ns);
        initialize_api(dso, cnx, GLESv1_CM);
        hnd->set(dso, GLESv1_CM);

        dso = load_angle("GLESv2", ns);
        initialize_api(dso, cnx, GLESv2);
        hnd->set(dso, GLESv2);
    }
    return hnd;
}

void Loader::attempt_to_init_angle_backend(void* dso, egl_connection_t* cnx) {
    cnx->angleGetDisplayPlatformFunc = dlsym(dso, "ANGLEGetDisplayPlatform");
    cnx->angleResetDisplayPlatformFunc = dlsym(dso, "ANGLEResetDisplayPlatform");

    if (cnx->angleGetDisplayPlatformFunc) {
        ALOGV("ANGLE GLES library loaded");
        cnx->angleLoaded = true;
        android::GraphicsEnv::getInstance().setDriverToLoad(android::GpuStatsInfo::Driver::ANGLE);
    } else {
        ALOGV("Native GLES library loaded");
        cnx->angleLoaded = false;
    }
}

Loader::driver_t* Loader::attempt_to_load_updated_driver(egl_connection_t* cnx) {
    ATRACE_CALL();

    android_namespace_t* ns = android::GraphicsEnv::getInstance().getDriverNamespace();
    if (!ns) {
        return nullptr;
    }

    ALOGD("Load updated gl driver.");
    android::GraphicsEnv::getInstance().setDriverToLoad(android::GpuStatsInfo::Driver::GL_UPDATED);
    driver_t* hnd = nullptr;
    void* dso = load_updated_driver("GLES", ns);
    if (dso) {
        initialize_api(dso, cnx, EGL | GLESv1_CM | GLESv2);
        hnd = new driver_t(dso);
        return hnd;
    }

    dso = load_updated_driver("EGL", ns);
    if (dso) {
        initialize_api(dso, cnx, EGL);
        hnd = new driver_t(dso);

        dso = load_updated_driver("GLESv1_CM", ns);
        initialize_api(dso, cnx, GLESv1_CM);
        hnd->set(dso, GLESv1_CM);

        dso = load_updated_driver("GLESv2", ns);
        initialize_api(dso, cnx, GLESv2);
        hnd->set(dso, GLESv2);
    }
    return hnd;
}

Loader::driver_t* Loader::attempt_to_load_system_driver(egl_connection_t* cnx, const char* suffix,
                                                        const bool exact) {
    ATRACE_CALL();
    if (suffix && strcmp(suffix, "angle") == 0) {
        // use system ANGLE driver
        android::GraphicsEnv::getInstance().setDriverToLoad(android::GpuStatsInfo::Driver::ANGLE);
    } else {
        android::GraphicsEnv::getInstance().setDriverToLoad(android::GpuStatsInfo::Driver::GL);
    }

    driver_t* hnd = nullptr;
    void* dso = load_system_driver("GLES", suffix, exact);
    if (dso) {
        initialize_api(dso, cnx, EGL | GLESv1_CM | GLESv2);
        hnd = new driver_t(dso);
        return hnd;
    }
    dso = load_system_driver("EGL", suffix, exact);
    if (dso) {
        initialize_api(dso, cnx, EGL);
        hnd = new driver_t(dso);

        dso = load_system_driver("GLESv1_CM", suffix, exact);
        initialize_api(dso, cnx, GLESv1_CM);
        hnd->set(dso, GLESv1_CM);

        dso = load_system_driver("GLESv2", suffix, exact);
        initialize_api(dso, cnx, GLESv2);
        hnd->set(dso, GLESv2);
    }
    return hnd;
}

void Loader::initialize_api(void* dso, egl_connection_t* cnx, uint32_t mask) {
    if (mask & EGL) {
        getProcAddress = (getProcAddressType)dlsym(dso, "eglGetProcAddress");

        ALOGE_IF(!getProcAddress,
                "can't find eglGetProcAddress() in EGL driver library");

        egl_t* egl = &cnx->egl;
        __eglMustCastToProperFunctionPointerType* curr =
            (__eglMustCastToProperFunctionPointerType*)egl;
        char const * const * api = egl_names;
        while (*api) {
            char const * name = *api;
            __eglMustCastToProperFunctionPointerType f =
                (__eglMustCastToProperFunctionPointerType)dlsym(dso, name);
            if (f == nullptr) {
                // couldn't find the entry-point, use eglGetProcAddress()
                f = getProcAddress(name);
                if (f == nullptr) {
                    f = (__eglMustCastToProperFunctionPointerType)nullptr;
                }
            }
            *curr++ = f;
            api++;
        }
    }

    if (mask & GLESv1_CM) {
        init_api(dso, gl_names_1, gl_names,
            (__eglMustCastToProperFunctionPointerType*)
                &cnx->hooks[egl_connection_t::GLESv1_INDEX]->gl,
            getProcAddress);
    }

    if (mask & GLESv2) {
        init_api(dso, gl_names, nullptr,
            (__eglMustCastToProperFunctionPointerType*)
                &cnx->hooks[egl_connection_t::GLESv2_INDEX]->gl,
            getProcAddress);
    }
}

} // namespace android