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 <stdlib.h>
28 #include <unistd.h>
29
30 #define LOG_TAG "HAL"
31 #include <log/log.h>
32
33 #if !defined(__ANDROID_RECOVERY__)
34 #include <vndksupport/linker.h>
35 #endif
36
37 /** Base path of the hal modules */
38 #if defined(__LP64__)
39 #define HAL_LIBRARY_PATH1 "/system/lib64/hw"
40 #define HAL_LIBRARY_PATH2 "/vendor/lib64/hw"
41 #define HAL_LIBRARY_PATH3 "/odm/lib64/hw"
42 #else
43 #define HAL_LIBRARY_PATH1 "/system/lib/hw"
44 #define HAL_LIBRARY_PATH2 "/vendor/lib/hw"
45 #define HAL_LIBRARY_PATH3 "/odm/lib/hw"
46 #endif
47
48 /**
49 * There are a set of variant filename for modules. The form of the filename
50 * is "<MODULE_ID>.variant.so" so for the led module the Dream variants
51 * of base "ro.product.board", "ro.board.platform" and "ro.arch" would be:
52 *
53 * led.trout.so
54 * led.msm7k.so
55 * led.ARMV6.so
56 * led.default.so
57 */
58
59 static const char *variant_keys[] = {
60 "ro.hardware", /* This goes first so that it can pick up a different
61 file on the emulator. */
62 "ro.product.board",
63 "ro.board.platform",
64 "ro.arch"
65 };
66
67 static const int HAL_VARIANT_KEYS_COUNT =
68 (sizeof(variant_keys)/sizeof(variant_keys[0]));
69
70 /**
71 * Load the file defined by the variant and if successful
72 * return the dlopen handle and the hmi.
73 * @return 0 = success, !0 = failure.
74 */
load(const char * id,const char * path,const struct hw_module_t ** pHmi)75 static int load(const char *id,
76 const char *path,
77 const struct hw_module_t **pHmi)
78 {
79 int status = -EINVAL;
80 void *handle = NULL;
81 struct hw_module_t *hmi = NULL;
82 #ifdef __ANDROID_VNDK__
83 const bool try_system = false;
84 #else
85 const bool try_system = true;
86 #endif
87
88 /*
89 * load the symbols resolving undefined symbols before
90 * dlopen returns. Since RTLD_GLOBAL is not or'd in with
91 * RTLD_NOW the external symbols will not be global
92 */
93 if (try_system &&
94 strncmp(path, HAL_LIBRARY_PATH1, strlen(HAL_LIBRARY_PATH1)) == 0) {
95 /* If the library is in system partition, no need to check
96 * sphal namespace. Open it with dlopen.
97 */
98 handle = dlopen(path, RTLD_NOW);
99 } else {
100 #if defined(__ANDROID_RECOVERY__)
101 handle = dlopen(path, RTLD_NOW);
102 #else
103 handle = android_load_sphal_library(path, RTLD_NOW);
104 #endif
105 }
106 if (handle == NULL) {
107 char const *err_str = dlerror();
108 ALOGE("load: module=%s\n%s", path, err_str?err_str:"unknown");
109 status = -EINVAL;
110 goto done;
111 }
112
113 /* Get the address of the struct hal_module_info. */
114 const char *sym = HAL_MODULE_INFO_SYM_AS_STR;
115 hmi = (struct hw_module_t *)dlsym(handle, sym);
116 if (hmi == NULL) {
117 ALOGE("load: couldn't find symbol %s", sym);
118 status = -EINVAL;
119 goto done;
120 }
121
122 /* Check that the id matches */
123 if (strcmp(id, hmi->id) != 0) {
124 ALOGE("load: id=%s != hmi->id=%s", id, hmi->id);
125 status = -EINVAL;
126 goto done;
127 }
128
129 hmi->dso = handle;
130
131 /* success */
132 status = 0;
133
134 done:
135 if (status != 0) {
136 hmi = NULL;
137 if (handle != NULL) {
138 dlclose(handle);
139 handle = NULL;
140 }
141 } else {
142 ALOGV("loaded HAL id=%s path=%s hmi=%p handle=%p",
143 id, path, hmi, handle);
144 }
145
146 *pHmi = hmi;
147
148 return status;
149 }
150
151 /*
152 * If path is in in_path.
153 */
path_in_path(const char * path,const char * in_path)154 static bool path_in_path(const char *path, const char *in_path) {
155 char real_path[PATH_MAX];
156 if (realpath(path, real_path) == NULL) return false;
157
158 char real_in_path[PATH_MAX];
159 if (realpath(in_path, real_in_path) == NULL) return false;
160
161 const size_t real_in_path_len = strlen(real_in_path);
162 if (strncmp(real_path, real_in_path, real_in_path_len) != 0) {
163 return false;
164 }
165
166 return strlen(real_path) > real_in_path_len &&
167 real_path[real_in_path_len] == '/';
168 }
169
170 /*
171 * Check if a HAL with given name and subname exists, if so return 0, otherwise
172 * otherwise return negative. On success path will contain the path to the HAL.
173 */
hw_module_exists(char * path,size_t path_len,const char * name,const char * subname)174 static int hw_module_exists(char *path, size_t path_len, const char *name,
175 const char *subname)
176 {
177 snprintf(path, path_len, "%s/%s.%s.so",
178 HAL_LIBRARY_PATH3, name, subname);
179 if (path_in_path(path, HAL_LIBRARY_PATH3) && access(path, R_OK) == 0)
180 return 0;
181
182 snprintf(path, path_len, "%s/%s.%s.so",
183 HAL_LIBRARY_PATH2, name, subname);
184 if (path_in_path(path, HAL_LIBRARY_PATH2) && access(path, R_OK) == 0)
185 return 0;
186
187 #ifndef __ANDROID_VNDK__
188 snprintf(path, path_len, "%s/%s.%s.so",
189 HAL_LIBRARY_PATH1, name, subname);
190 if (path_in_path(path, HAL_LIBRARY_PATH1) && access(path, R_OK) == 0)
191 return 0;
192 #endif
193
194 return -ENOENT;
195 }
196
hw_get_module_by_class(const char * class_id,const char * inst,const struct hw_module_t ** module)197 int hw_get_module_by_class(const char *class_id, const char *inst,
198 const struct hw_module_t **module)
199 {
200 int i = 0;
201 char prop[PATH_MAX] = {0};
202 char path[PATH_MAX] = {0};
203 char name[PATH_MAX] = {0};
204 char prop_name[PATH_MAX] = {0};
205
206
207 if (inst)
208 snprintf(name, PATH_MAX, "%s.%s", class_id, inst);
209 else
210 strlcpy(name, class_id, PATH_MAX);
211
212 /*
213 * Here we rely on the fact that calling dlopen multiple times on
214 * the same .so will simply increment a refcount (and not load
215 * a new copy of the library).
216 * We also assume that dlopen() is thread-safe.
217 */
218
219 /* First try a property specific to the class and possibly instance */
220 snprintf(prop_name, sizeof(prop_name), "ro.hardware.%s", name);
221 if (property_get(prop_name, prop, NULL) > 0) {
222 if (hw_module_exists(path, sizeof(path), name, prop) == 0) {
223 goto found;
224 }
225 }
226
227 /* Loop through the configuration variants looking for a module */
228 for (i=0 ; i<HAL_VARIANT_KEYS_COUNT; i++) {
229 if (property_get(variant_keys[i], prop, NULL) == 0) {
230 continue;
231 }
232 if (hw_module_exists(path, sizeof(path), name, prop) == 0) {
233 goto found;
234 }
235 }
236
237 /* Nothing found, try the default */
238 if (hw_module_exists(path, sizeof(path), name, "default") == 0) {
239 goto found;
240 }
241
242 return -ENOENT;
243
244 found:
245 /* load the module, if this fails, we're doomed, and we should not try
246 * to load a different variant. */
247 return load(class_id, path, module);
248 }
249
hw_get_module(const char * id,const struct hw_module_t ** module)250 int hw_get_module(const char *id, const struct hw_module_t **module)
251 {
252 return hw_get_module_by_class(id, NULL, module);
253 }
254