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