1//
2// Copyright 2016 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 "bluetooth_address.h"
18
19#include <cutils/properties.h>
20#include <errno.h>
21#include <fcntl.h>
22#include <unistd.h>
23#include <utils/Log.h>
24
25namespace android {
26namespace hardware {
27namespace bluetooth {
28namespace V1_0 {
29namespace implementation {
30
31void BluetoothAddress::bytes_to_string(const uint8_t* addr, char* addr_str) {
32  sprintf(addr_str, "%02x:%02x:%02x:%02x:%02x:%02x", addr[0], addr[1], addr[2],
33          addr[3], addr[4], addr[5]);
34}
35
36bool BluetoothAddress::string_to_bytes(const char* addr_str, uint8_t* addr) {
37  if (addr_str == NULL) return false;
38  if (strnlen(addr_str, kStringLength) != kStringLength) return false;
39  unsigned char trailing_char = '\0';
40
41  return (sscanf(addr_str, "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx%1c",
42                 &addr[0], &addr[1], &addr[2], &addr[3], &addr[4], &addr[5],
43                 &trailing_char) == kBytes);
44}
45
46bool BluetoothAddress::get_local_address(uint8_t* local_addr) {
47  char property[PROPERTY_VALUE_MAX] = {0};
48  bool valid_bda = false;
49
50  // Get local bdaddr storage path from a system property.
51  if (property_get(PROPERTY_BT_BDADDR_PATH, property, NULL)) {
52    int addr_fd;
53
54    ALOGD("%s: Trying %s", __func__, property);
55
56    addr_fd = open(property, O_RDONLY);
57    if (addr_fd != -1) {
58      char address[kStringLength + 1] = {0};
59      int bytes_read = read(addr_fd, address, kStringLength);
60      if (bytes_read == -1) {
61        ALOGE("%s: Error reading address from %s: %s", __func__, property,
62              strerror(errno));
63      }
64      close(addr_fd);
65
66      // Null terminate the string.
67      address[kStringLength] = '\0';
68
69      // If the address is not all zeros, then use it.
70      const uint8_t zero_bdaddr[kBytes] = {0, 0, 0, 0, 0, 0};
71      if ((string_to_bytes(address, local_addr)) &&
72          (memcmp(local_addr, zero_bdaddr, kBytes) != 0)) {
73        valid_bda = true;
74        ALOGD("%s: Got Factory BDA %s", __func__, address);
75      } else {
76        ALOGE("%s: Got Invalid BDA '%s' from %s", __func__, address, property);
77      }
78    }
79  }
80
81  // No BDADDR found in the file. Look for BDA in a factory property.
82  if (!valid_bda && property_get(FACTORY_BDADDR_PROPERTY, property, NULL) &&
83      string_to_bytes(property, local_addr)) {
84    valid_bda = true;
85  }
86
87  // No factory BDADDR found. Look for a previously stored BDA.
88  if (!valid_bda && property_get(PERSIST_BDADDR_PROPERTY, property, NULL) &&
89      string_to_bytes(property, local_addr)) {
90    valid_bda = true;
91  }
92
93  /* Generate new BDA if necessary */
94  if (!valid_bda) {
95    char bdstr[kStringLength + 1];
96
97    /* No autogen BDA. Generate one now. */
98    local_addr[0] = 0x22;
99    local_addr[1] = 0x22;
100    local_addr[2] = (uint8_t)rand();
101    local_addr[3] = (uint8_t)rand();
102    local_addr[4] = (uint8_t)rand();
103    local_addr[5] = (uint8_t)rand();
104
105    /* Convert to ascii, and store as a persistent property */
106    bytes_to_string(local_addr, bdstr);
107
108    ALOGE("%s: No preset BDA! Generating BDA: %s for prop %s", __func__,
109          (char*)bdstr, PERSIST_BDADDR_PROPERTY);
110    ALOGE("%s: This is a bug in the platform!  Please fix!", __func__);
111
112    if (property_set(PERSIST_BDADDR_PROPERTY, (char*)bdstr) < 0) {
113      ALOGE("%s: Failed to set random BDA in prop %s", __func__,
114            PERSIST_BDADDR_PROPERTY);
115      valid_bda = false;
116    } else {
117      valid_bda = true;
118    }
119  }
120
121  return valid_bda;
122}
123
124}  // namespace implementation
125}  // namespace V1_0
126}  // namespace bluetooth
127}  // namespace hardware
128}  // namespace android
129