1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * 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 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 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. 15 */ 16 17 #include <hardware/hardware.h> 18 19 #include <cutils/properties.h> 20 21 #include <dlfcn.h> 22 #include <string.h> 23 #include <pthread.h> 24 #include <errno.h> 25 #include <limits.h> 26 #include <stdio.h> 27 #include <unistd.h> 28 29 #define LOG_TAG "HAL" 30 #include <log/log.h> 31 32 #include <vndksupport/linker.h> 33 34 /** Base path of the hal modules */ 35 #if defined(__LP64__) 36 #define HAL_LIBRARY_PATH1 "/system/lib64/hw" 37 #define HAL_LIBRARY_PATH2 "/vendor/lib64/hw" 38 #define HAL_LIBRARY_PATH3 "/odm/lib64/hw" 39 #else 40 #define HAL_LIBRARY_PATH1 "/system/lib/hw" 41 #define HAL_LIBRARY_PATH2 "/vendor/lib/hw" 42 #define HAL_LIBRARY_PATH3 "/odm/lib/hw" 43 #endif 44 45 /** 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: 49 * 50 * led.trout.so 51 * led.msm7k.so 52 * led.ARMV6.so 53 * led.default.so 54 */ 55 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. */ 59 "ro.product.board", 60 "ro.board.platform", 61 "ro.arch" 62 }; 63 64 static const int HAL_VARIANT_KEYS_COUNT = 65 (sizeof(variant_keys)/sizeof(variant_keys[0])); 66 67 /** 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. 71 */ 72 static int load(const char *id, 73 const char *path, 74 const struct hw_module_t **pHmi) 75 { 76 int status = -EINVAL; 77 void *handle = NULL; 78 struct hw_module_t *hmi = NULL; 79 80 /* 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 84 */ 85 if (strncmp(path, "/system/", 8) == 0) { 86 /* If the library is in system partition, no need to check 87 * sphal namespace. Open it with dlopen. 88 */ 89 handle = dlopen(path, RTLD_NOW); 90 } else { 91 handle = android_load_sphal_library(path, RTLD_NOW); 92 } 93 if (handle == NULL) { 94 char const *err_str = dlerror(); 95 ALOGE("load: module=%s\n%s", path, err_str?err_str:"unknown"); 96 status = -EINVAL; 97 goto done; 98 } 99 100 /* Get the address of the struct hal_module_info. */ 101 const char *sym = HAL_MODULE_INFO_SYM_AS_STR; 102 hmi = (struct hw_module_t *)dlsym(handle, sym); 103 if (hmi == NULL) { 104 ALOGE("load: couldn't find symbol %s", sym); 105 status = -EINVAL; 106 goto done; 107 } 108 109 /* Check that the id matches */ 110 if (strcmp(id, hmi->id) != 0) { 111 ALOGE("load: id=%s != hmi->id=%s", id, hmi->id); 112 status = -EINVAL; 113 goto done; 114 } 115 116 hmi->dso = handle; 117 118 /* success */ 119 status = 0; 120 121 done: 122 if (status != 0) { 123 hmi = NULL; 124 if (handle != NULL) { 125 dlclose(handle); 126 handle = NULL; 127 } 128 } else { 129 ALOGV("loaded HAL id=%s path=%s hmi=%p handle=%p", 130 id, path, *pHmi, handle); 131 } 132 133 *pHmi = hmi; 134 135 return status; 136 } 137 138 /* 139 * Check if a HAL with given name and subname exists, if so return 0, otherwise 140 * otherwise return negative. On success path will contain the path to the HAL. 141 */ 142 static int hw_module_exists(char *path, size_t path_len, const char *name, 143 const char *subname) 144 { 145 snprintf(path, path_len, "%s/%s.%s.so", 146 HAL_LIBRARY_PATH3, name, subname); 147 if (access(path, R_OK) == 0) 148 return 0; 149 150 snprintf(path, path_len, "%s/%s.%s.so", 151 HAL_LIBRARY_PATH2, name, subname); 152 if (access(path, R_OK) == 0) 153 return 0; 154 155 snprintf(path, path_len, "%s/%s.%s.so", 156 HAL_LIBRARY_PATH1, name, subname); 157 if (access(path, R_OK) == 0) 158 return 0; 159 160 return -ENOENT; 161 } 162 163 int hw_get_module_by_class(const char *class_id, const char *inst, 164 const struct hw_module_t **module) 165 { 166 int i = 0; 167 char prop[PATH_MAX] = {0}; 168 char path[PATH_MAX] = {0}; 169 char name[PATH_MAX] = {0}; 170 char prop_name[PATH_MAX] = {0}; 171 172 173 if (inst) 174 snprintf(name, PATH_MAX, "%s.%s", class_id, inst); 175 else 176 strlcpy(name, class_id, PATH_MAX); 177 178 /* 179 * Here we rely on the fact that calling dlopen multiple times on 180 * the same .so will simply increment a refcount (and not load 181 * a new copy of the library). 182 * We also assume that dlopen() is thread-safe. 183 */ 184 185 /* First try a property specific to the class and possibly instance */ 186 snprintf(prop_name, sizeof(prop_name), "ro.hardware.%s", name); 187 if (property_get(prop_name, prop, NULL) > 0) { 188 if (hw_module_exists(path, sizeof(path), name, prop) == 0) { 189 goto found; 190 } 191 } 192 193 /* Loop through the configuration variants looking for a module */ 194 for (i=0 ; i<HAL_VARIANT_KEYS_COUNT; i++) { 195 if (property_get(variant_keys[i], prop, NULL) == 0) { 196 continue; 197 } 198 if (hw_module_exists(path, sizeof(path), name, prop) == 0) { 199 goto found; 200 } 201 } 202 203 /* Nothing found, try the default */ 204 if (hw_module_exists(path, sizeof(path), name, "default") == 0) { 205 goto found; 206 } 207 208 return -ENOENT; 209 210 found: 211 /* load the module, if this fails, we're doomed, and we should not try 212 * to load a different variant. */ 213 return load(class_id, path, module); 214 } 215 216 int hw_get_module(const char *id, const struct hw_module_t **module) 217 { 218 return hw_get_module_by_class(id, NULL, module); 219 } 220
