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
44  // Always try to load the default Bluetooth stack on GN builds.
45  void *handle = dlopen(kBluetoothLibraryName, RTLD_NOW);
46  if (!handle) {
47    char const *err_str = dlerror();
48    HULOGERR("%s", err_str ? err_str : "error unknown");
49    goto error;
50  }
51
52  // Get the address of the struct hal_module_info.
53  const char *sym = HAL_MODULE_INFO_SYM_AS_STR;
54  struct hw_module_t *hmi = (struct hw_module_t *)dlsym(handle, sym);
55  if (!hmi) {
56    HULOGERR("%s", sym);
57    goto error;
58  }
59
60  // Check that the id matches.
61  if (strcmp(id, hmi->id) != 0) {
62    HULOGERR("id=%s does not match HAL module ID: %s", id, hmi->id);
63    goto error;
64  }
65
66  hmi->dso = handle;
67
68  // Success.
69  LOG_INFO(
70      LOG_TAG, "[%s] loaded HAL id=%s path=%s hmi=%p handle=%p",
71      __func__, id, kBluetoothLibraryName, hmi, handle);
72
73  *module = hmi;
74  return 0;
75
76error:
77  *module = NULL;
78  if (handle)
79    dlclose(handle);
80
81  return -EINVAL;
82}
83
84#endif  // defined(OS_GENERIC)
85
86int hal_util_load_bt_library(const struct hw_module_t **module) {
87#if defined(OS_GENERIC)
88  return load_bt_library(module);
89#else  // !defined(OS_GENERIC)
90  return hw_get_module(BT_STACK_MODULE_ID, module);
91#endif  // defined(OS_GENERIC)
92}
93