1 /*
2 * Copyright (C) 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 "wifi_system/supplicant_manager.h"
18
19 #include <android-base/logging.h>
20 #include <cutils/properties.h>
21 #include <fcntl.h>
22 #include <string.h>
23 #include <sys/stat.h>
24 #include <unistd.h>
25
26 // This ugliness is necessary to access internal implementation details
27 // of the property subsystem.
28 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
29 #include <sys/_system_properties.h>
30
31 namespace android {
32 namespace wifi_system {
33 namespace {
34
35 const char kSupplicantInitProperty[] = "init.svc.wpa_supplicant";
36 const char kSupplicantServiceName[] = "wpa_supplicant";
37
38 } // namespace
39
StartSupplicant()40 bool SupplicantManager::StartSupplicant() {
41 char supp_status[PROPERTY_VALUE_MAX] = {'\0'};
42 int count = 200; /* wait at most 20 seconds for completion */
43 const prop_info* pi;
44 unsigned serial = 0;
45
46 /* Check whether already running */
47 if (property_get(kSupplicantInitProperty, supp_status, NULL) &&
48 strcmp(supp_status, "running") == 0) {
49 return true;
50 }
51
52 /*
53 * Get a reference to the status property, so we can distinguish
54 * the case where it goes stopped => running => stopped (i.e.,
55 * it start up, but fails right away) from the case in which
56 * it starts in the stopped state and never manages to start
57 * running at all.
58 */
59 pi = __system_property_find(kSupplicantInitProperty);
60 if (pi != NULL) {
61 serial = __system_property_serial(pi);
62 }
63
64 property_set("ctl.start", kSupplicantServiceName);
65 sched_yield();
66
67 while (count-- > 0) {
68 if (pi == NULL) {
69 pi = __system_property_find(kSupplicantInitProperty);
70 }
71 if (pi != NULL) {
72 /*
73 * property serial updated means that init process is scheduled
74 * after we sched_yield, further property status checking is based on this
75 */
76 if (__system_property_serial(pi) != serial) {
77 __system_property_read(pi, NULL, supp_status);
78 if (strcmp(supp_status, "running") == 0) {
79 return true;
80 } else if (strcmp(supp_status, "stopped") == 0) {
81 return false;
82 }
83 }
84 }
85 usleep(100000);
86 }
87 return false;
88 }
89
StopSupplicant()90 bool SupplicantManager::StopSupplicant() {
91 char supp_status[PROPERTY_VALUE_MAX] = {'\0'};
92 int count = 50; /* wait at most 5 seconds for completion */
93
94 /* Check whether supplicant already stopped */
95 if (property_get(kSupplicantInitProperty, supp_status, NULL) &&
96 strcmp(supp_status, "stopped") == 0) {
97 return true;
98 }
99
100 property_set("ctl.stop", kSupplicantServiceName);
101 sched_yield();
102
103 while (count-- > 0) {
104 if (property_get(kSupplicantInitProperty, supp_status, NULL)) {
105 if (strcmp(supp_status, "stopped") == 0) return true;
106 }
107 usleep(100000);
108 }
109 LOG(ERROR) << "Failed to stop supplicant";
110 return false;
111 }
112
IsSupplicantRunning()113 bool SupplicantManager::IsSupplicantRunning() {
114 char supp_status[PROPERTY_VALUE_MAX] = {'\0'};
115 if (property_get(kSupplicantInitProperty, supp_status, NULL)) {
116 return strcmp(supp_status, "running") == 0;
117 }
118 return false; // Failed to read service status from init.
119 }
120
121 } // namespace wifi_system
122 } // namespace android
123