Code

collectd.conf(5): Update the "LatencyRate" option.
[collectd.git] / 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  **/
25 #include "collectd.h"
27 #include "common.h"
28 #include "plugin.h"
30 #if HAVE_TERMIOS_H && HAVE_SYS_IOCTL_H && HAVE_MATH_H
31 # include <termios.h>
32 # include <sys/ioctl.h>
33 # include <math.h>
34 #else
35 # error "No applicable input method."
36 #endif
38 static int fd = -1;
40 #define LINE_LENGTH 14
41 static int multimeter_read_value(double *value)
42 {
43         int retry = 3; /* sometimes we receive garbadge */
45         do
46         {
47                 struct timeval time_end;
49                 tcflush(fd, TCIFLUSH);
51                 if (gettimeofday (&time_end, NULL) < 0)
52                 {
53                         char errbuf[1024];
54                         ERROR ("multimeter plugin: gettimeofday failed: %s",
55                                         sstrerror (errno, errbuf,
56                                                 sizeof (errbuf)));
57                         return (-1);
58                 }
59                 time_end.tv_sec++;      
61                 while (1)
62                 {
63                         char buf[LINE_LENGTH];
64                         char *range;
65                         int status;
66                         fd_set rfds;
67                         struct timeval timeout;
68                         struct timeval time_now;
70                         status = swrite (fd, "D", 1);
71                         if (status < 0)
72                         {
73                                 ERROR ("multimeter plugin: swrite failed.");
74                                 return (-1);
75                         }
77                         FD_ZERO(&rfds);
78                         FD_SET(fd, &rfds);
80                         if (gettimeofday (&time_now, NULL) < 0)
81                         {
82                                 char errbuf[1024];
83                                 ERROR ("multimeter plugin: "
84                                                 "gettimeofday failed: %s",
85                                                 sstrerror (errno, errbuf,
86                                                         sizeof (errbuf)));
87                                 return (-1);
88                         }
89                         if (timeval_cmp (time_end, time_now, &timeout) < 0)
90                                 break;
92                         status = select(fd+1, &rfds, NULL, NULL, &timeout);
94                         if (status > 0) /* usually we succeed */
95                         {
96                                 status = read(fd, buf, LINE_LENGTH);
98                                 if ((status < 0) && ((errno == EAGAIN) || (errno == EINTR)))
99                                         continue;
101                                 /* Format: "DC 00.000mV  \r" */
102                                 if (status > 0 && status == LINE_LENGTH)
103                                 {
104                                         *value = strtod(buf + 2, &range);
106                                         if ( range > (buf + 6) )
107                                         {
108                                                 range = buf + 9;
110                                                 switch ( *range )
111                                                 {
112                                                         case 'p': *value *= 1.0E-12; break;
113                                                         case 'n': *value *= 1.0E-9; break;
114                                                         case 'u': *value *= 1.0E-6; break;
115                                                         case 'm': *value *= 1.0E-3; break;
116                                                         case 'k': *value *= 1.0E3; break;
117                                                         case 'M': *value *= 1.0E6; break;
118                                                         case 'G': *value *= 1.0E9; break;
119                                                 }
120                                         }
121                                         else
122                                                 return (-1); /* Overflow */
124                                         return (0); /* value received */
125                                 }
126                                 else break;
127                         }
128                         else if (!status) /* Timeout */
129                         {
130                                 break;
131                         }
132                         else if ((status == -1) && ((errno == EAGAIN) || (errno == EINTR)))
133                         {
134                                 continue;
135                         }
136                         else /* status == -1 */
137                         {
138                                 char errbuf[1024];
139                                 ERROR ("multimeter plugin: "
140                                                 "select failed: %s",
141                                                 sstrerror (errno, errbuf, sizeof (errbuf)));
142                                 break;
143                         }
144                 }
145         } while (--retry);
147         return (-2);  /* no value received */
148 } /* int multimeter_read_value */
150 static int multimeter_init (void)
152         char device[] = "/dev/ttyS ";
154         for (int i = 0; i < 10; i++)
155         {
156                 device[strlen(device)-1] = i + '0';
158                 if ((fd = open(device, O_RDWR | O_NOCTTY)) != -1)
159                 {
160                         struct termios tios = { 0 };
161                         int rts = TIOCM_RTS;
162                         double value;
164                         tios.c_cflag = B1200 | CS7 | CSTOPB | CREAD | CLOCAL;
165                         tios.c_iflag = IGNBRK | IGNPAR;
166                         tios.c_oflag = 0;
167                         tios.c_lflag = 0;
168                         tios.c_cc[VTIME] = 3;
169                         tios.c_cc[VMIN]  = LINE_LENGTH;
171                         tcflush(fd, TCIFLUSH);
172                         tcsetattr(fd, TCSANOW, &tios);
173                         ioctl(fd, TIOCMBIC, &rts);
175                         if (multimeter_read_value (&value) < -1)
176                         {
177                                 close (fd);
178                                 fd = -1;
179                         }
180                         else
181                         {
182                                 INFO ("multimeter plugin: Device "
183                                                 "found at %s", device);
184                                 return (0);
185                         }
186                 }
187         }
189         ERROR ("multimeter plugin: No device found");
190         return (-1);
192 #undef LINE_LENGTH
194 static void multimeter_submit (double value)
196         value_list_t vl = VALUE_LIST_INIT;
198         vl.values = &(value_t) { .gauge = value };
199         vl.values_len = 1;
200         sstrncpy (vl.plugin, "multimeter", sizeof (vl.plugin));
201         sstrncpy (vl.type, "multimeter", sizeof (vl.type));
203         plugin_dispatch_values (&vl);
206 static int multimeter_read (void)
208         double value;
210         if (fd < 0)
211                 return (-1);
213         if (multimeter_read_value (&value) != 0)
214                 return (-1);
216         multimeter_submit (value);
217         return (0);
218 } /* int multimeter_read */
220 static int multimeter_shutdown (void)
222         if (fd >= 0)
223         {
224                 close (fd);
225                 fd = -1;
226         }
228         return (0);
231 void module_register (void)
233         plugin_register_init ("multimeter", multimeter_init);
234         plugin_register_read ("multimeter", multimeter_read);
235         plugin_register_shutdown ("multimeter", multimeter_shutdown);
236 } /* void module_register */