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.
39static const char kBluetoothLibraryName[] = "libbluetooth.default.so";
40
41static 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
76error:
77  *module = NULL;
78  if (handle) dlclose(handle);
79
80  return -EINVAL;
81}
82
83#endif  // defined(OS_GENERIC)
84
85int 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