x5/khatus_sensor_time.c

   1 #include <assert.h>
   2 #include <ctype.h>
   3 #include <errno.h>
   4 #include <fcntl.h>
   5 #include <signal.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_time.h"
  14
  15 #define usage(...) {print_usage(); fprintf(stderr, "Error:\n    " __VA_ARGS__); exit(EXIT_FAILURE);}
  16
  17 #define MAX_LEN 20
  18 #define END_OF_MESSAGE '\n'
  19
  20 char *argv0 = NULL;
  21
  22 double opt_interval = 1.0;
  23 char *opt_fmt = "%a %b %d %H:%M:%S";
  24 char *fifo_name = 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             "    | -f string  # format string\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_fmt = calloc(strlen(optarg), sizeof(char));
  48                         strcpy(opt_fmt, 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         fifo_name = argv[optind];
  74         debug("fifo_name: %s\n", fifo_name);
  75         if (!fifo_name)
  76                 usage("No filename was provided\n");
  77 }
  78
  79 int
  80 main(int argc, char **argv)
  81 {
  82         argv0 = argv[0];
  83
  84         time_t t;
  85         struct timespec ti;
  86         char buf[MAX_LEN];
  87
  88         int fd = -1;
  89
  90         int n = 0;  /* written */
  91         int r = 0;  /* remaining */
  92         int i = 0;  /* buffer position */
  93
  94         opt_parse(argc, argv);
  95
  96         signal(SIGPIPE, SIG_IGN);  /* Handling manually */
  97
  98         memset(buf, '\0', MAX_LEN);
  99         ti = timespec_of_float(opt_interval);
 100         for (;;) {
 101                 debug("openning \"%s\"\n", fifo_name);
 102                 fd = open(fifo_name, O_WRONLY);
 103                 if (fd < 0)
 104                         fatal("Failed to open FIFO file: \"%s\". Error: %s\n",
 105                             fifo_name,
 106                             strerror(errno));
 107                 debug("openned. fd: %d\n", fd);
 108                 t = time(NULL);
 109                 strftime(buf, MAX_LEN, opt_fmt, localtime(&t));
 110                 r = strlen(buf);
 111                 buf[r] = END_OF_MESSAGE;
 112                 for (i = 0; (n = write(fd, buf + i++, 1)) && r; r--)
 113                         ;
 114                 if (n < 0)
 115                         switch (errno) {
 116                         case EPIPE:
 117                                 error("Broken pipe. Msg buf: %s\n", buf);
 118                                 break;
 119                         default:
 120                                 fatal(
 121                                     "Failed to write to %s. "
 122                                     "Err num: %d, Err msg: %s\n",
 123                                     fifo_name,
 124                                     errno,
 125                                     strerror(errno));
 126                         }
 127                 if (close(fd) < 0)
 128                         fatal("Failed to close %s. Err num: %d, Err msg: %s\n",
 129                             fifo_name,
 130                             errno,
 131                             strerror(errno));
 132                 fd = -1;
 133                 debug("closed. fd: %d\n", fd);
 134                 snooze(&ti);
 135         }
 136         return EXIT_SUCCESS;
 137 }