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 #ifdef __ANDROID_VNDK__ 80 const bool try_system = false; 81 #else 82 const bool try_system = true; 83 #endif 84 85 /* 86 * load the symbols resolving undefined symbols before 87 * dlopen returns. Since RTLD_GLOBAL is not or'd in with 88 * RTLD_NOW the external symbols will not be global 89 */ 90 if (try_system && 91 strncmp(path, HAL_LIBRARY_PATH1, strlen(HAL_LIBRARY_PATH1)) == 0) { 92 /* If the library is in system partition, no need to check 93 * sphal namespace. Open it with dlopen. 94 */ 95 handle = dlopen(path, RTLD_NOW); 96 } else { 97 handle = android_load_sphal_library(path, RTLD_NOW); 98 } 99 if (handle == NULL) { 100 char const *err_str = dlerror(); 101 ALOGE("load: module=%s\n%s", path, err_str?err_str:"unknown"); 102 status = -EINVAL; 103 goto done; 104 } 105 106 /* Get the address of the struct hal_module_info. */ 107 const char *sym = HAL_MODULE_INFO_SYM_AS_STR; 108 hmi = (struct hw_module_t *)dlsym(handle, sym); 109 if (hmi == NULL) { 110 ALOGE("load: couldn't find symbol %s", sym); 111 status = -EINVAL; 112 goto done; 113 } 114 115 /* Check that the id matches */ 116 if (strcmp(id, hmi->id) != 0) { 117 ALOGE("load: id=%s != hmi->id=%s", id, hmi->id); 118 status = -EINVAL; 119 goto done; 120 } 121 122 hmi->dso = handle; 123 124 /* success */ 125 status = 0; 126 127 done: 128 if (status != 0) { 129 hmi = NULL; 130 if (handle != NULL) { 131 dlclose(handle); 132 handle = NULL; 133 } 134 } else { 135 ALOGV("loaded HAL id=%s path=%s hmi=%p handle=%p", 136 id, path, *pHmi, handle); 137 } 138 139 *pHmi = hmi; 140 141 return status; 142 } 143 144 /* 145 * Check if a HAL with given name and subname exists, if so return 0, otherwise 146 * otherwise return negative. On success path will contain the path to the HAL. 147 */ 148 static int hw_module_exists(char *path, size_t path_len, const char *name, 149 const char *subname) 150 { 151 snprintf(path, path_len, "%s/%s.%s.so", 152 HAL_LIBRARY_PATH3, name, subname); 153 if (access(path, R_OK) == 0) 154 return 0; 155 156 snprintf(path, path_len, "%s/%s.%s.so", 157 HAL_LIBRARY_PATH2, name, subname); 158 if (access(path, R_OK) == 0) 159 return 0; 160 161 #ifndef __ANDROID_VNDK__ 162 snprintf(path, path_len, "%s/%s.%s.so", 163 HAL_LIBRARY_PATH1, name, subname); 164 if (access(path, R_OK) == 0) 165 return 0; 166 #endif 167 168 return -ENOENT; 169 } 170 171 int hw_get_module_by_class(const char *class_id, const char *inst, 172 const struct hw_module_t **module) 173 { 174 int i = 0; 175 char prop[PATH_MAX] = {0}; 176 char path[PATH_MAX] = {0}; 177 char name[PATH_MAX] = {0}; 178 char prop_name[PATH_MAX] = {0}; 179 180 181 if (inst) 182 snprintf(name, PATH_MAX, "%s.%s", class_id, inst); 183 else 184 strlcpy(name, class_id, PATH_MAX); 185 186 /* 187 * Here we rely on the fact that calling dlopen multiple times on 188 * the same .so will simply increment a refcount (and not load 189 * a new copy of the library). 190 * We also assume that dlopen() is thread-safe. 191 */ 192 193 /* First try a property specific to the class and possibly instance */ 194 snprintf(prop_name, sizeof(prop_name), "ro.hardware.%s", name); 195 if (property_get(prop_name, prop, NULL) > 0) { 196 if (hw_module_exists(path, sizeof(path), name, prop) == 0) { 197 goto found; 198 } 199 } 200 201 /* Loop through the configuration variants looking for a module */ 202 for (i=0 ; i<HAL_VARIANT_KEYS_COUNT; i++) { 203 if (property_get(variant_keys[i], prop, NULL) == 0) { 204 continue; 205 } 206 if (hw_module_exists(path, sizeof(path), name, prop) == 0) { 207 goto found; 208 } 209 } 210 211 /* Nothing found, try the default */ 212 if (hw_module_exists(path, sizeof(path), name, "default") == 0) { 213 goto found; 214 } 215 216 return -ENOENT; 217 218 found: 219 /* load the module, if this fails, we're doomed, and we should not try 220 * to load a different variant. */ 221 return load(class_id, path, module); 222 } 223 224 int hw_get_module(const char *id, const struct hw_module_t **module) 225 { 226 return hw_get_module_by_class(id, NULL, module); 227 } 228
