2 * Copyright (C) 2008 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #include <hardware/hardware.h>
19 #include <cutils/properties.h>
32 #include <vndksupport/linker.h>
34 /** Base path of the hal modules */
36 #define HAL_LIBRARY_PATH1 "/system/lib64/hw"
37 #define HAL_LIBRARY_PATH2 "/vendor/lib64/hw"
38 #define HAL_LIBRARY_PATH3 "/odm/lib64/hw"
40 #define HAL_LIBRARY_PATH1 "/system/lib/hw"
41 #define HAL_LIBRARY_PATH2 "/vendor/lib/hw"
42 #define HAL_LIBRARY_PATH3 "/odm/lib/hw"
46 * There are a set of variant filename for modules. The form of the filename
47 * is "<MODULE_ID>.variant.so" so for the led module the Dream variants
48 * of base "ro.product.board", "ro.board.platform" and "ro.arch" would be:
56 static const char *variant_keys[] = {
57 "ro.hardware", /* This goes first so that it can pick up a different
58 file on the emulator. */
64 static const int HAL_VARIANT_KEYS_COUNT =
65 (sizeof(variant_keys)/sizeof(variant_keys[0]));
68 * Load the file defined by the variant and if successful
69 * return the dlopen handle and the hmi.
70 * @return 0 = success, !0 = failure.
72 static int load(const char *id,
74 const struct hw_module_t **pHmi)
78 struct hw_module_t *hmi = NULL;
81 * load the symbols resolving undefined symbols before
82 * dlopen returns. Since RTLD_GLOBAL is not or'd in with
83 * RTLD_NOW the external symbols will not be global
85 handle = android_load_sphal_library(path, RTLD_NOW);
87 char const *err_str = dlerror();
88 ALOGE("load: module=%s\n%s", path, err_str?err_str:"unknown");
93 /* Get the address of the struct hal_module_info. */
94 const char *sym = HAL_MODULE_INFO_SYM_AS_STR;
95 hmi = (struct hw_module_t *)dlsym(handle, sym);
97 ALOGE("load: couldn't find symbol %s", sym);
102 /* Check that the id matches */
103 if (strcmp(id, hmi->id) != 0) {
104 ALOGE("load: id=%s != hmi->id=%s", id, hmi->id);
117 if (handle != NULL) {
122 ALOGV("loaded HAL id=%s path=%s hmi=%p handle=%p",
123 id, path, *pHmi, handle);
132 * Check if a HAL with given name and subname exists, if so return 0, otherwise
133 * otherwise return negative. On success path will contain the path to the HAL.
135 static int hw_module_exists(char *path, size_t path_len, const char *name,
138 snprintf(path, path_len, "%s/%s.%s.so",
139 HAL_LIBRARY_PATH3, name, subname);
140 if (access(path, R_OK) == 0)
143 snprintf(path, path_len, "%s/%s.%s.so",
144 HAL_LIBRARY_PATH2, name, subname);
145 if (access(path, R_OK) == 0)
148 snprintf(path, path_len, "%s/%s.%s.so",
149 HAL_LIBRARY_PATH1, name, subname);
150 if (access(path, R_OK) == 0)
156 int hw_get_module_by_class(const char *class_id, const char *inst,
157 const struct hw_module_t **module)
160 char prop[PATH_MAX] = {0};
161 char path[PATH_MAX] = {0};
162 char name[PATH_MAX] = {0};
163 char prop_name[PATH_MAX] = {0};
167 snprintf(name, PATH_MAX, "%s.%s", class_id, inst);
169 strlcpy(name, class_id, PATH_MAX);
172 * Here we rely on the fact that calling dlopen multiple times on
173 * the same .so will simply increment a refcount (and not load
174 * a new copy of the library).
175 * We also assume that dlopen() is thread-safe.
178 /* First try a property specific to the class and possibly instance */
179 snprintf(prop_name, sizeof(prop_name), "ro.hardware.%s", name);
180 if (property_get(prop_name, prop, NULL) > 0) {
181 if (hw_module_exists(path, sizeof(path), name, prop) == 0) {
186 /* Loop through the configuration variants looking for a module */
187 for (i=0 ; i<HAL_VARIANT_KEYS_COUNT; i++) {
188 if (property_get(variant_keys[i], prop, NULL) == 0) {
191 if (hw_module_exists(path, sizeof(path), name, prop) == 0) {
196 /* Nothing found, try the default */
197 if (hw_module_exists(path, sizeof(path), name, "default") == 0) {
204 /* load the module, if this fails, we're doomed, and we should not try
205 * to load a different variant. */
206 return load(class_id, path, module);
209 int hw_get_module(const char *id, const struct hw_module_t **module)
211 return hw_get_module_by_class(id, NULL, module);