src/multimeter.c

   1 /**
   2  * collectd - src/multimeter.c
   3  * Copyright (C) 2005,2006  Peter Holik
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  18  *
  19  * Authors:
  20  *   Peter Holik <peter at holik.at>
  21  *
  22  * Used multimeter: Metex M-4650CR
  23  **/
  24
  25 #include "collectd.h"
  26 #include "common.h"
  27 #include "plugin.h"
  28
  29 #if HAVE_TERMIOS_H && HAVE_SYS_IOCTL_H && HAVE_MATH_H
  30 # include <termios.h>
  31 # include <sys/ioctl.h>
  32 # include <math.h>
  33 # define MULTIMETER_HAVE_READ 1
  34 #else
  35 # define MULTIMETER_HAVE_READ 0
  36 # error "multimeter cannot read!"
  37 #endif
  38
  39 static data_source_t data_source[1] =
  40 {
  41         {"value", DS_TYPE_GAUGE, NAN, NAN}
  42 };
  43
  44 static data_set_t data_set =
  45 {
  46         "multimeter", 1, data_source
  47 };
  48
  49 #if MULTIMETER_HAVE_READ
  50 static int fd = -1;
  51
  52 static int multimeter_timeval_sub (struct timeval *tv1, struct timeval *tv2,
  53                 struct timeval *res)
  54 {
  55         if ((tv1->tv_sec < tv2->tv_sec) ||
  56             ((tv1->tv_sec == tv2->tv_sec) && (tv1->tv_usec < tv2->tv_usec)))
  57                 return (-1);
  58
  59         res->tv_sec  = tv1->tv_sec  - tv2->tv_sec;
  60         res->tv_usec = tv1->tv_usec - tv2->tv_usec;
  61
  62         assert ((res->tv_sec > 0) || ((res->tv_sec == 0) && (res->tv_usec > 0)));
  63
  64         while (res->tv_usec < 0)
  65         {
  66                 res->tv_usec += 1000000;
  67                 res->tv_sec--;
  68         }
  69         return (0);
  70 }
  71 #define LINE_LENGTH 14
  72 static int multimeter_read_value(double *value)
  73 {
  74         int retry = 3; /* sometimes we receive garbadge */
  75
  76         do
  77         {
  78                 struct timeval time_end;
  79
  80                 tcflush(fd, TCIFLUSH);
  81
  82                 if (gettimeofday (&time_end, NULL) < 0)
  83                 {
  84                         syslog (LOG_ERR, "multimeter plugin: gettimeofday failed: %s",
  85                                 strerror (errno));
  86                         return (-1);
  87                 }
  88                 time_end.tv_sec++;
  89
  90                 while (1)
  91                 {
  92                         char buf[LINE_LENGTH];
  93                         char *range;
  94                         int status;
  95                         fd_set rfds;
  96                         struct timeval timeout;
  97                         struct timeval time_now;
  98
  99                         write(fd, "D", 1);
 100
 101                         FD_ZERO(&rfds);
 102                         FD_SET(fd, &rfds);
 103
 104                         if (gettimeofday (&time_now, NULL) < 0)
 105                         {
 106                                 syslog (LOG_ERR, "multimeter plugin: "
 107                                                 "gettimeofday failed: %s",
 108                                                 strerror (errno));
 109                                 return (-1);
 110                         }
 111                         if (multimeter_timeval_sub (&time_end, &time_now, &timeout) == -1)
 112                                 break;
 113
 114                         status = select(fd+1, &rfds, NULL, NULL, &timeout);
 115
 116                         if (status > 0) /* usually we succeed */
 117                         {
 118                                 status = read(fd, buf, LINE_LENGTH);
 119
 120                                 if ((status < 0) && ((errno == EAGAIN) || (errno == EINTR)))
 121                                         continue;
 122
 123                                 /* Format: "DC 00.000mV  \r" */
 124                                 if (status > 0 && status == LINE_LENGTH)
 125                                 {
 126                                         *value = strtod(buf + 2, &range);
 127
 128                                         if ( range > (buf + 6) )
 129                                         {
 130                                                 range = buf + 9;
 131
 132                                                 switch ( *range )
 133                                                 {
 134                                                         case 'p': *value *= 1.0E-12; break;
 135                                                         case 'n': *value *= 1.0E-9; break;
 136                                                         case 'u': *value *= 1.0E-6; break;
 137                                                         case 'm': *value *= 1.0E-3; break;
 138                                                         case 'k': *value *= 1.0E3; break;
 139                                                         case 'M': *value *= 1.0E6; break;
 140                                                         case 'G': *value *= 1.0E9; break;
 141                                                 }
 142                                         }
 143                                         else
 144                                                 return (-1); /* Overflow */
 145
 146                                         return (0); /* value received */
 147                                 }
 148                                 else break;
 149                         }
 150                         else if (!status) /* Timeout */
 151                         {
 152                                 break;
 153                         }
 154                         else if ((status == -1) && ((errno == EAGAIN) || (errno == EINTR)))
 155                         {
 156                                 continue;
 157                         }
 158                         else /* status == -1 */
 159                         {
 160                                 syslog (LOG_ERR, "multimeter plugin: "
 161                                                 "select failed: %s",
 162                                                 strerror (errno));
 163                                 break;
 164                         }
 165                 }
 166         } while (--retry);
 167
 168         return (-2);  /* no value received */
 169 } /* int multimeter_read_value */
 170
 171 static int multimeter_init (void)
 172 {
 173         int i;
 174         char device[] = "/dev/ttyS ";
 175
 176         for (i = 0; i < 10; i++)
 177         {
 178                 device[strlen(device)-1] = i + '0';
 179
 180                 if ((fd = open(device, O_RDWR | O_NOCTTY)) > 0)
 181                 {
 182                         struct termios tios;
 183                         int rts = TIOCM_RTS;
 184                         double value;
 185
 186                         tios.c_cflag = B1200 | CS7 | CSTOPB | CREAD | CLOCAL;
 187                         tios.c_iflag = IGNBRK | IGNPAR;
 188                         tios.c_oflag = 0;
 189                         tios.c_lflag = 0;
 190                         tios.c_cc[VTIME] = 3;
 191                         tios.c_cc[VMIN]  = LINE_LENGTH;
 192
 193                         tcflush(fd, TCIFLUSH);
 194                         tcsetattr(fd, TCSANOW, &tios);
 195                         ioctl(fd, TIOCMBIC, &rts);
 196
 197                         if (multimeter_read_value (&value) < -1)
 198                         {
 199                                 close (fd);
 200                                 fd = -1;
 201                         }
 202                         else
 203                         {
 204                                 syslog (LOG_INFO, "multimeter plugin: Device "
 205                                                 "found at %s", device);
 206                                 return (0);
 207                         }
 208                 }
 209         }
 210
 211         syslog (LOG_ERR, "multimeter plugin: No device found");
 212         return (-1);
 213 }
 214 #undef LINE_LENGTH
 215
 216 static void multimeter_submit (double value)
 217 {
 218         value_t values[1];
 219         value_list_t vl = VALUE_LIST_INIT;
 220
 221         values[0].gauge = value;
 222
 223         vl.values = values;
 224         vl.values_len = 1;
 225         vl.time = time (NULL);
 226         strcpy (vl.host, hostname_g);
 227         strcpy (vl.plugin, "multimeter");
 228
 229         plugin_dispatch_values ("multimeter", &vl);
 230 }
 231
 232 static int multimeter_read (void)
 233 {
 234         double value;
 235
 236         if (fd < 0)
 237                 return (-1);
 238
 239         if (multimeter_read_value (&value) != 0)
 240                 return (-1);
 241
 242         multimeter_submit (value);
 243         return (0);
 244 } /* int multimeter_read */
 245
 246 static int multimeter_shutdown (void)
 247 {
 248         if (fd >= 0)
 249         {
 250                 close (fd);
 251                 fd = -1;
 252         }
 253
 254         return (0);
 255 }
 256 #endif /* MULTIMETER_HAVE_READ */
 257
 258 void module_register (void)
 259 {
 260         plugin_register_data_set (&data_set);
 261
 262 #if MULTIMETER_HAVE_READ
 263         plugin_register_init ("multimeter", multimeter_init);
 264         plugin_register_read ("multimeter", multimeter_read);
 265         plugin_register_shutdown ("multimeter", multimeter_shutdown);
 266 #endif /* MULTIMETER_HAVE_READ */
 267 }