1 //
2 // Copyright (C) 2015 Google, Inc.
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 #define LOG_TAG "hal_util"
18
19 #include <hardware/bluetooth.h>
20 #include <hardware/hardware.h>
21
22 #include <dlfcn.h>
23 #include <errno.h>
24 #include <string.h>
25
26 #include "btcore/include/hal_util.h"
27 #include "osi/include/log.h"
28
29 #if defined(OS_GENERIC)
30
31 // TODO(armansito): All logging macros should include __func__ by default (see
32 // Bug: 22671731)
33 #define HULOGERR(fmt, args...) \
34 LOG_ERROR(LOG_TAG, "[%s] failed to load the Bluetooth library: " fmt, \
35 __func__, ##args)
36
37 // TODO(armansito): It might be better to pass the library name in a more
38 // generic manner as opposed to hard-coding it here.
39 static const char kBluetoothLibraryName[] = "libbluetooth.default.so";
40
load_bt_library(const struct hw_module_t ** module)41 static int load_bt_library(const struct hw_module_t** module) {
42 const char* id = BT_STACK_MODULE_ID;
43 const char* sym = HAL_MODULE_INFO_SYM_AS_STR;
44 struct hw_module_t* hmi = nullptr;
45
46 // Always try to load the default Bluetooth stack on GN builds.
47 void* handle = dlopen(kBluetoothLibraryName, RTLD_NOW);
48 if (!handle) {
49 char const* err_str = dlerror();
50 HULOGERR("%s", err_str ? err_str : "error unknown");
51 goto error;
52 }
53
54 // Get the address of the struct hal_module_info.
55 hmi = (struct hw_module_t*)dlsym(handle, sym);
56 if (!hmi) {
57 HULOGERR("%s", sym);
58 goto error;
59 }
60
61 // Check that the id matches.
62 if (strcmp(id, hmi->id) != 0) {
63 HULOGERR("id=%s does not match HAL module ID: %s", id, hmi->id);
64 goto error;
65 }
66
67 hmi->dso = handle;
68
69 // Success.
70 LOG_INFO(LOG_TAG, "[%s] loaded HAL id=%s path=%s hmi=%p handle=%p", __func__,
71 id, kBluetoothLibraryName, hmi, handle);
72
73 *module = hmi;
74 return 0;
75
76 error:
77 *module = NULL;
78 if (handle) dlclose(handle);
79
80 return -EINVAL;
81 }
82
83 #endif // defined(OS_GENERIC)
84
hal_util_load_bt_library(const struct hw_module_t ** module)85 int hal_util_load_bt_library(const struct hw_module_t** module) {
86 #if defined(OS_GENERIC)
87 return load_bt_library(module);
88 #else // !defined(OS_GENERIC)
89 return hw_get_module(BT_STACK_MODULE_ID, module);
90 #endif // defined(OS_GENERIC)
91 }
92