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 #if MULTIMETER_HAVE_READ
  40 static int fd = -1;
  41
  42 static int multimeter_timeval_sub (struct timeval *tv1, struct timeval *tv2,
  43                 struct timeval *res)
  44 {
  45         if ((tv1->tv_sec < tv2->tv_sec) ||
  46             ((tv1->tv_sec == tv2->tv_sec) && (tv1->tv_usec < tv2->tv_usec)))
  47                 return (-1);
  48
  49         res->tv_sec  = tv1->tv_sec  - tv2->tv_sec;
  50         res->tv_usec = tv1->tv_usec - tv2->tv_usec;
  51
  52         assert ((res->tv_sec > 0) || ((res->tv_sec == 0) && (res->tv_usec > 0)));
  53
  54         while (res->tv_usec < 0)
  55         {
  56                 res->tv_usec += 1000000;
  57                 res->tv_sec--;
  58         }
  59         return (0);
  60 }
  61 #define LINE_LENGTH 14
  62 static int multimeter_read_value(double *value)
  63 {
  64         int retry = 3; /* sometimes we receive garbadge */
  65
  66         do
  67         {
  68                 struct timeval time_end;
  69
  70                 tcflush(fd, TCIFLUSH);
  71
  72                 if (gettimeofday (&time_end, NULL) < 0)
  73                 {
  74                         char errbuf[1024];
  75                         ERROR ("multimeter plugin: gettimeofday failed: %s",
  76                                         sstrerror (errno, errbuf,
  77                                                 sizeof (errbuf)));
  78                         return (-1);
  79                 }
  80                 time_end.tv_sec++;
  81
  82                 while (1)
  83                 {
  84                         char buf[LINE_LENGTH];
  85                         char *range;
  86                         int status;
  87                         fd_set rfds;
  88                         struct timeval timeout;
  89                         struct timeval time_now;
  90
  91                         write(fd, "D", 1);
  92
  93                         FD_ZERO(&rfds);
  94                         FD_SET(fd, &rfds);
  95
  96                         if (gettimeofday (&time_now, NULL) < 0)
  97                         {
  98                                 char errbuf[1024];
  99                                 ERROR ("multimeter plugin: "
 100                                                 "gettimeofday failed: %s",
 101                                                 sstrerror (errno, errbuf,
 102                                                         sizeof (errbuf)));
 103                                 return (-1);
 104                         }
 105                         if (multimeter_timeval_sub (&time_end, &time_now, &timeout) == -1)
 106                                 break;
 107
 108                         status = select(fd+1, &rfds, NULL, NULL, &timeout);
 109
 110                         if (status > 0) /* usually we succeed */
 111                         {
 112                                 status = read(fd, buf, LINE_LENGTH);
 113
 114                                 if ((status < 0) && ((errno == EAGAIN) || (errno == EINTR)))
 115                                         continue;
 116
 117                                 /* Format: "DC 00.000mV  \r" */
 118                                 if (status > 0 && status == LINE_LENGTH)
 119                                 {
 120                                         *value = strtod(buf + 2, &range);
 121
 122                                         if ( range > (buf + 6) )
 123                                         {
 124                                                 range = buf + 9;
 125
 126                                                 switch ( *range )
 127                                                 {
 128                                                         case 'p': *value *= 1.0E-12; break;
 129                                                         case 'n': *value *= 1.0E-9; break;
 130                                                         case 'u': *value *= 1.0E-6; break;
 131                                                         case 'm': *value *= 1.0E-3; break;
 132                                                         case 'k': *value *= 1.0E3; break;
 133                                                         case 'M': *value *= 1.0E6; break;
 134                                                         case 'G': *value *= 1.0E9; break;
 135                                                 }
 136                                         }
 137                                         else
 138                                                 return (-1); /* Overflow */
 139
 140                                         return (0); /* value received */
 141                                 }
 142                                 else break;
 143                         }
 144                         else if (!status) /* Timeout */
 145                         {
 146                                 break;
 147                         }
 148                         else if ((status == -1) && ((errno == EAGAIN) || (errno == EINTR)))
 149                         {
 150                                 continue;
 151                         }
 152                         else /* status == -1 */
 153                         {
 154                                 char errbuf[1024];
 155                                 ERROR ("multimeter plugin: "
 156                                                 "select failed: %s",
 157                                                 sstrerror (errno, errbuf, sizeof (errbuf)));
 158                                 break;
 159                         }
 160                 }
 161         } while (--retry);
 162
 163         return (-2);  /* no value received */
 164 } /* int multimeter_read_value */
 165
 166 static int multimeter_init (void)
 167 {
 168         int i;
 169         char device[] = "/dev/ttyS ";
 170
 171         for (i = 0; i < 10; i++)
 172         {
 173                 device[strlen(device)-1] = i + '0';
 174
 175                 if ((fd = open(device, O_RDWR | O_NOCTTY)) > 0)
 176                 {
 177                         struct termios tios;
 178                         int rts = TIOCM_RTS;
 179                         double value;
 180
 181                         tios.c_cflag = B1200 | CS7 | CSTOPB | CREAD | CLOCAL;
 182                         tios.c_iflag = IGNBRK | IGNPAR;
 183                         tios.c_oflag = 0;
 184                         tios.c_lflag = 0;
 185                         tios.c_cc[VTIME] = 3;
 186                         tios.c_cc[VMIN]  = LINE_LENGTH;
 187
 188                         tcflush(fd, TCIFLUSH);
 189                         tcsetattr(fd, TCSANOW, &tios);
 190                         ioctl(fd, TIOCMBIC, &rts);
 191
 192                         if (multimeter_read_value (&value) < -1)
 193                         {
 194                                 close (fd);
 195                                 fd = -1;
 196                         }
 197                         else
 198                         {
 199                                 INFO ("multimeter plugin: Device "
 200                                                 "found at %s", device);
 201                                 return (0);
 202                         }
 203                 }
 204         }
 205
 206         ERROR ("multimeter plugin: No device found");
 207         return (-1);
 208 }
 209 #undef LINE_LENGTH
 210
 211 static void multimeter_submit (double value)
 212 {
 213         value_t values[1];
 214         value_list_t vl = VALUE_LIST_INIT;
 215
 216         values[0].gauge = value;
 217
 218         vl.values = values;
 219         vl.values_len = 1;
 220         vl.time = time (NULL);
 221         strcpy (vl.host, hostname_g);
 222         strcpy (vl.plugin, "multimeter");
 223
 224         plugin_dispatch_values ("multimeter", &vl);
 225 }
 226
 227 static int multimeter_read (void)
 228 {
 229         double value;
 230
 231         if (fd < 0)
 232                 return (-1);
 233
 234         if (multimeter_read_value (&value) != 0)
 235                 return (-1);
 236
 237         multimeter_submit (value);
 238         return (0);
 239 } /* int multimeter_read */
 240
 241 static int multimeter_shutdown (void)
 242 {
 243         if (fd >= 0)
 244         {
 245                 close (fd);
 246                 fd = -1;
 247         }
 248
 249         return (0);
 250 }
 251 #endif /* MULTIMETER_HAVE_READ */
 252
 253 void module_register (void)
 254 {
 255 #if MULTIMETER_HAVE_READ
 256         plugin_register_init ("multimeter", multimeter_init);
 257         plugin_register_read ("multimeter", multimeter_read);
 258         plugin_register_shutdown ("multimeter", multimeter_shutdown);
 259 #endif /* MULTIMETER_HAVE_READ */
 260 } /* void module_register */