| /* |
| * Copyright (C) 2008 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. |
| */ |
| |
| #include <hardware/hardware.h> |
| |
| #include <cutils/properties.h> |
| |
| #include <dlfcn.h> |
| #include <string.h> |
| #include <pthread.h> |
| #include <errno.h> |
| #include <limits.h> |
| |
| #define LOG_TAG "HAL" |
| #include <utils/Log.h> |
| |
| /** Base path of the hal modules */ |
| #define HAL_LIBRARY_PATH "/system/lib/hw" |
| |
| /** |
| * There are a set of variant filename for modules. The form of the filename |
| * is "<MODULE_ID>.variant.so" so for the led module the Dream variants |
| * of base "ro.product.board", "ro.board.platform" and "ro.arch" would be: |
| * |
| * led.trout.so |
| * led.msm7k.so |
| * led.ARMV6.so |
| * led.default.so |
| */ |
| |
| #define HAL_DEFAULT_VARIANT "default" |
| static const char *variant_keys[] = { |
| "ro.hardware", /* This goes first so that it can pick up a different |
| file on the emulator. */ |
| "ro.product.board", |
| "ro.board.platform", |
| "ro.arch" |
| }; |
| #define HAL_VARIANT_KEYS_COUNT (sizeof(variant_keys)/sizeof(variant_keys[0])) |
| |
| /** |
| * Load the file defined by the variant and if succesfull |
| * return the dlopen handle and the hmi. |
| * @return 0 = success, !0 = failure. |
| */ |
| static int load(const char *id, |
| const char *variant, |
| const struct hw_module_t **pHmi) |
| { |
| int status; |
| void *handle; |
| const struct hw_module_t *hmi; |
| char path[PATH_MAX]; |
| |
| /* Construct the path. */ |
| snprintf(path, sizeof(path), "%s/%s.%s.so", HAL_LIBRARY_PATH, id, variant); |
| |
| LOGV("load: E id=%s path=%s", id, path); |
| |
| /* |
| * load the symbols resolving undefined symbols before |
| * dlopen returns. Since RTLD_GLOBAL is not or'd in with |
| * RTLD_NOW the external symbols will not be global |
| */ |
| handle = dlopen(path, RTLD_NOW); |
| if (handle == NULL) { |
| char const *err_str = dlerror(); |
| LOGW("load: module=%s error=%s", path, err_str); |
| status = -EINVAL; |
| goto done; |
| } |
| |
| /* Get the address of the struct hal_module_info. */ |
| const char *sym = HAL_MODULE_INFO_SYM_AS_STR; |
| hmi = (const struct hw_module_t *)dlsym(handle, sym); |
| if (hmi == NULL) { |
| char const *err_str = dlerror(); |
| LOGE("load: couldn't find symbol %s", sym); |
| status = -EINVAL; |
| goto done; |
| } |
| |
| /* Check that the id matches */ |
| if (strcmp(id, hmi->id) != 0) { |
| LOGE("load: id=%s != hmi->id=%s", id, hmi->id); |
| status = -EINVAL; |
| goto done; |
| } |
| |
| /* success */ |
| status = 0; |
| |
| done: |
| if (status != 0) { |
| hmi = NULL; |
| if (handle != NULL) { |
| dlclose(handle); |
| handle = NULL; |
| } |
| } |
| |
| *pHmi = hmi; |
| |
| LOGV("load: X id=%s path=%s hmi=%p handle=%p status=%d", |
| id, path, *pHmi, handle, status); |
| return status; |
| } |
| |
| int hw_get_module(const char *id, const struct hw_module_t **module) |
| { |
| int status; |
| int i; |
| const struct hw_module_t *hmi = NULL; |
| char prop[PATH_MAX]; |
| |
| /* |
| * Here we rely on the fact that calling dlopen multiple times on |
| * the same .so will simply increment a refcount (and not load |
| * a new copy of the library). |
| * We also assume that dlopen() is thread-safe. |
| */ |
| |
| LOGV("hal_module_info_get: Load module id=%s", id); |
| |
| status = -EINVAL; |
| |
| /* Loop through the configuration variants looking for a module */ |
| for (i = 0; (status != 0) && (i < HAL_VARIANT_KEYS_COUNT); i++) { |
| if (property_get(variant_keys[i], prop, NULL) == 0) { |
| continue; |
| } |
| status = load(id, prop, &hmi); |
| } |
| |
| /* Try default */ |
| if (status != 0) { |
| status = load(id, HAL_DEFAULT_VARIANT, &hmi); |
| } |
| |
| *module = hmi; |
| LOGV("hal_module_info_get: X id=%s hmi=%p status=%d", id, hmi, status); |
| |
| return status; |
| } |