1 /**
2  * Copyright © 2016 IBM Corporation
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 "monitor.hpp"
18 
19 #include <fcntl.h>
20 
21 #include <phosphor-logging/lg2.hpp>
22 
23 namespace phosphor
24 {
25 namespace gpio
26 {
27 
28 // systemd service to kick start a target.
29 constexpr auto SYSTEMD_SERVICE = "org.freedesktop.systemd1";
30 constexpr auto SYSTEMD_ROOT = "/org/freedesktop/systemd1";
31 constexpr auto SYSTEMD_INTERFACE = "org.freedesktop.systemd1.Manager";
32 
33 // Callback handler when there is an activity on the FD
34 int Monitor::processEvents(sd_event_source*, int, uint32_t, void* userData)
35 {
36     lg2::info("GPIO line altered");
37     auto monitor = static_cast<Monitor*>(userData);
38 
39     monitor->analyzeEvent();
40     return 0;
41 }
42 
43 // Analyzes the GPIO event
44 void Monitor::analyzeEvent()
45 {
46     // Data returned
47     struct input_event ev
48     {};
49     int rc = 0;
50 
51     // While testing, observed that not having a loop here was leading
52     // into events being missed.
53     while (rc >= 0)
54     {
55         // Wait until no more events are available on the device.
56         rc = libevdev_next_event(devicePtr.get(), LIBEVDEV_READ_FLAG_NORMAL,
57                                  &ev);
58         if (rc < 0)
59         {
60             // There was an error waiting for events, mostly that there are no
61             // events to be read.. So continue waiting...
62             return;
63         };
64 
65         if (rc == LIBEVDEV_READ_STATUS_SUCCESS)
66         {
67             if (ev.type == EV_SYN && ev.code == SYN_REPORT)
68             {
69                 continue;
70             }
71             else if (ev.code == key && ev.value == polarity)
72             {
73                 // If the code/value is what we are interested in, declare done.
74                 // User supplied systemd unit
75                 if (!target.empty())
76                 {
77                     auto bus = sdbusplus::bus::new_default();
78                     auto method =
79                         bus.new_method_call(SYSTEMD_SERVICE, SYSTEMD_ROOT,
80                                             SYSTEMD_INTERFACE, "StartUnit");
81                     method.append(target);
82                     method.append("replace");
83 
84                     bus.call_noreply(method);
85                 }
86 
87                 if (!continueAfterKeyPress)
88                 {
89                     // This marks the completion of handling the gpio assertion
90                     // and the app can exit
91                     complete = true;
92                 }
93                 return;
94             }
95         }
96     };
97 
98     return;
99 }
100 
101 } // namespace gpio
102 } // namespace phosphor
103