power/powerbtnd.c

   1 /**
   2  * A daemon to simulate power button of Android
   3  *
   4  * Copyright (C) 2011 The Android-x86 Open Source Project
   5  *
   6  * by Chih-Wei Huang <cwhuang@linux.org.tw>
   7  *
   8  * Licensed under GPLv2 or later
   9  *
  10  **/
  11
  12 #define LOG_TAG "powerbtn"
  13
  14 #include <sys/stat.h>
  15 #include <poll.h>
  16 #include <fcntl.h>
  17 #include <errno.h>
  18 #include <dirent.h>
  19 #include <cutils/log.h>
  20 #include <linux/input.h>
  21 #include <linux/uinput.h>
  22
  23 const int MAX_POWERBTNS = 3;
  24
  25 int openfds(struct pollfd pfds[])
  26 {
  27         int cnt = 0;
  28         const char *dirname = "/dev/input";
  29         DIR *dir;
  30         if ((dir = opendir(dirname))) {
  31                 int fd;
  32                 struct dirent *de;
  33                 while ((de = readdir(dir))) {
  34                         if (de->d_name[0] != 'e') // eventX
  35                                 continue;
  36                         char name[PATH_MAX];
  37                         snprintf(name, PATH_MAX, "%s/%s", dirname, de->d_name);
  38                         fd = open(name, O_RDWR);
  39                         if (fd < 0) {
  40                                 LOGE("could not open %s, %s", name, strerror(errno));
  41                                 continue;
  42                         }
  43                         name[sizeof(name) - 1] = '\0';
  44                         if (ioctl(fd, EVIOCGNAME(sizeof(name) - 1), &name) < 1) {
  45                                 LOGE("could not get device name for %s, %s\n", name, strerror(errno));
  46                                 name[0] = '\0';
  47                         }
  48
  49                         // TODO: parse /etc/excluded-input-devices.xml
  50                         if (!strcmp(name, "Power Button")) {
  51                                 LOGI("open %s(%s) ok", de->d_name, name);
  52                                 pfds[cnt].events = POLLIN;
  53                                 pfds[cnt++].fd = fd;
  54                                 if (cnt < MAX_POWERBTNS)
  55                                         continue;
  56                                 else
  57                                         break;
  58                         }
  59                         close(fd);
  60                 }
  61                 closedir(dir);
  62         }
  63
  64         return cnt;
  65 }
  66
  67 int main()
  68 {
  69         struct pollfd pfds[MAX_POWERBTNS];
  70         int cnt = openfds(pfds);
  71         int pollres;
  72
  73         int ufd = open("/dev/uinput", O_WRONLY | O_NDELAY);
  74         if (ufd >= 0) {
  75                 struct uinput_user_dev ud;
  76                 memset(&ud, 0, sizeof(ud));
  77                 strcpy(ud.name, "Android Power Button");
  78                 write(ufd, &ud, sizeof(ud));
  79                 ioctl(ufd, UI_SET_EVBIT, EV_KEY);
  80                 ioctl(ufd, UI_SET_KEYBIT, KEY_POWER);
  81                 ioctl(ufd, UI_DEV_CREATE, 0);
  82         } else {
  83                 LOGE("could not open uinput device: %s", strerror(errno));
  84                 return -1;
  85         }
  86
  87         while ((pollres = poll(pfds, cnt, -1))) {
  88                 int i;
  89                 if (pollres < 0) {
  90                         LOGE("poll error: %s", strerror(errno));
  91                         break;
  92                 }
  93                 for (i = 0; i < cnt; ++i) {
  94                         if (pfds[i].revents & POLLIN) {
  95                                 struct input_event iev;
  96                                 size_t res = read(pfds[i].fd, &iev, sizeof(iev));
  97                                 if (res < sizeof(iev)) {
  98                                         LOGW("insufficient input data(%d)? fd=%d", res, pfds[i].fd);
  99                                         continue;
 100                                 }
 101                                 LOGV("type=%d scancode=%d value=%d from fd=%d", iev.type, iev.code, iev.value, pfds[i].fd);
 102                                 if (iev.type == EV_KEY) {
 103                                         switch (iev.code)
 104                                         {
 105                                                 case KEY_POWER:
 106                                                         if (!iev.value)
 107                                                                 sleep(2);
 108                                                         break;
 109                                         }
 110                                 }
 111
 112                                 write(ufd, &iev, sizeof(iev));
 113                         }
 114                 }
 115         }
 116
 117         return 0;
 118 }