khatus_sensor_battery.c

   1 #include <assert.h>
   2 #include <ctype.h>
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <limits.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <time.h>
  10 #include <unistd.h>
  11
  12 #include "khatus_lib_log.h"
  13 #include "khatus_lib_sensor.h"
  14 #include "khatus_lib_time.h"
  15
  16 #define usage(...) {print_usage(); fprintf(stderr, "Error:\n    " __VA_ARGS__); exit(EXIT_FAILURE);}
  17
  18 #define MAX_LEN 20
  19
  20 char *argv0;
  21
  22 double  opt_interval = 1.0;
  23 char   *opt_battery  = "BAT0";
  24 char   *opt_fifo     = NULL;
  25
  26 void
  27 print_usage()
  28 {
  29         printf(
  30             "%s: [OPT ...] FIFO\n"
  31             "\n"
  32             "FIFO = string    # path to fifo file\n"
  33             "OPT = -i int     # interval\n"
  34             "    | -b string  # battery file name from /sys/class/power_supply/\n"
  35             "    | -h         # help message (i.e. what you're reading now :) )\n",
  36             argv0);
  37 }
  38
  39 void
  40 opt_parse(int argc, char **argv)
  41 {
  42         char c;
  43
  44         while ((c = getopt(argc, argv, "f:i:h")) != -1)
  45                 switch (c) {
  46                 case 'f':
  47                         opt_battery = calloc(strlen(optarg), sizeof(char));
  48                         strcpy(opt_battery, optarg);
  49                         break;
  50                 case 'i':
  51                         opt_interval = atof(optarg);
  52                         break;
  53                 case 'h':
  54                         print_usage();
  55                         exit(EXIT_SUCCESS);
  56                 case '?':
  57                         if (optopt == 'f' || optopt == 'i')
  58                                 fprintf(stderr,
  59                                         "Option -%c requires an argument.\n",
  60                                         optopt);
  61                         else if (isprint(optopt))
  62                                 fprintf (stderr,
  63                                         "Unknown option `-%c'.\n",
  64                                         optopt);
  65                         else
  66                                 fprintf(stderr,
  67                                         "Unknown option character `\\x%x'.\n",
  68                                         optopt);
  69                         exit(EXIT_FAILURE);
  70                 default:
  71                         assert(0);
  72                 }
  73         opt_fifo = argv[optind];
  74         debug("opt_fifo: %s\n", opt_fifo);
  75         if (!opt_fifo)
  76                 usage("No filename was provided\n");
  77 }
  78
  79 int
  80 get_capacity(char *buf, char *path)
  81 {
  82         FILE *fp;
  83         int cap;
  84
  85         if (!(fp = fopen(path, "r")))
  86                 fatal("Failed to open %s. errno: %d, msg: %s\n",
  87                     path, errno, strerror(errno));
  88
  89         switch (fscanf(fp, "%d", &cap)) {
  90         case -1: fatal("EOF\n");
  91         case  0: fatal("Read 0\n");
  92         case  1: break;
  93         default: assert(0);
  94         }
  95         fclose(fp);
  96         return snprintf(buf, 6, "%3d%%\n", cap);
  97 }
  98
  99 int
 100 main(int argc, char **argv)
 101 {
 102         argv0 = argv[0];
 103
 104         char  buf[10];
 105         char path[PATH_MAX];
 106         char *path_fmt = "/sys/class/power_supply/%s/capacity";
 107         struct timespec ti = timespec_of_float(opt_interval);
 108
 109         opt_parse(argc, argv);
 110
 111         memset(path, '\0', PATH_MAX);
 112         snprintf(path, PATH_MAX, path_fmt, opt_battery);
 113         loop(
 114             &ti,
 115             opt_fifo,
 116             buf,
 117             (SENSOR_FUN_T)    get_capacity,
 118             (SENSOR_PARAMS_T) path
 119         );
 120 }