backlightd/backlightd.cpp at main · vale-max/backlightd · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
#include <errno.h>
#include <syslog.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <cstdio>
#include <cstdlib>
#include <X11/Xlib.h>
#include <X11/extensions/dpms.h>
#include <chrono>
#include <thread>
#include <csignal>

using namespace std;
using namespace std::chrono;

void signalHandler (int signum)
{

    syslog(LOG_INFO,"backlightd: stopped");
    exit(signum);
}

void backlight_on()
{

    int fd = open("/sys/class/backlight/soc:backlight/bl_power", O_WRONLY);
    if (fd == -1) {
        perror("Unable to open /sys/class/backlight/soc:backlight/bl_power");
        exit(1);
    }

    if (write(fd, "0", 1) != 1) {
        perror("Error writing to /sys/class/backlight/soc:backlight/bl_power");
        exit(1);
    }

    close(fd);
    syslog(LOG_INFO,"backlightd: set backlight on");
//    fprintf(stderr, "Set backlight on\n");
}

void backlight_off()
{
   int fd = open("/sys/class/backlight/soc:backlight/bl_power", O_WRONLY);
    if (fd == -1) {
        perror("Unable to open /sys/class/backlight/soc:backlight/bl_power");
        exit(1);
    }

    if (write(fd, "4", 1) != 1) {
        perror("Error writing to /sys/class/backlight/soc:backlight/bl_power");
        exit(1);
    }

    close(fd);
    syslog(LOG_INFO,"backlightd: set backlight off");
//   fprintf(stderr, "backlightd: set backlight off\n");
}

int main(int argc, char *argv[])
{
    signal(SIGINT, signalHandler);
    Display *dpy;
    dpy = XOpenDisplay(NULL);
    if (dpy == NULL)
    {
        fprintf(stderr, "%s:  unable to open display\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    BOOL prev = true;
    BOOL onoff;
    CARD16 state;
    syslog(LOG_INFO,"backlightd: started");
    backlight_on();
    while(true)
    {
        DPMSInfo(dpy, &state, &onoff);
        switch (onoff)
        {
           case false:
              if (prev == false)
                 {
                    backlight_on();
                    prev=true;
                 }
              break;
           case true:
              switch (state)
              {
                 case DPMSModeOn:
                     if (prev == false)
                        {
                          backlight_on();
                          prev=true;
                        }
                     break;
                 case DPMSModeSuspend:
                 case DPMSModeStandby:
                 case DPMSModeOff:
                     if (prev == true)
                        {
                          backlight_off();
                          prev=false;
                        }
                     break;
                 default:
                     break;
              }
              break;
           default:
              break;
        }
        this_thread::sleep_for(milliseconds(200));
    }
    return 0;
}