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"
26 #include "common.h"
27 #include "plugin.h"
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
39 static data_source_t data_source[1] =
40 {
41 {"value", DS_TYPE_GAUGE, NAN, NAN}
42 };
44 static data_set_t data_set =
45 {
46 "multimeter", 1, data_source
47 };
49 #if MULTIMETER_HAVE_READ
50 static int fd = -1;
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);
59 res->tv_sec = tv1->tv_sec - tv2->tv_sec;
60 res->tv_usec = tv1->tv_usec - tv2->tv_usec;
62 assert ((res->tv_sec > 0) || ((res->tv_sec == 0) && (res->tv_usec > 0)));
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 */
76 do
77 {
78 struct timeval time_end;
80 tcflush(fd, TCIFLUSH);
82 if (gettimeofday (&time_end, NULL) < 0)
83 {
84 char errbuf[1024];
85 ERROR ("multimeter plugin: gettimeofday failed: %s",
86 sstrerror (errno, errbuf,
87 sizeof (errbuf)));
88 return (-1);
89 }
90 time_end.tv_sec++;
92 while (1)
93 {
94 char buf[LINE_LENGTH];
95 char *range;
96 int status;
97 fd_set rfds;
98 struct timeval timeout;
99 struct timeval time_now;
101 write(fd, "D", 1);
103 FD_ZERO(&rfds);
104 FD_SET(fd, &rfds);
106 if (gettimeofday (&time_now, NULL) < 0)
107 {
108 char errbuf[1024];
109 ERROR ("multimeter plugin: "
110 "gettimeofday failed: %s",
111 sstrerror (errno, errbuf,
112 sizeof (errbuf)));
113 return (-1);
114 }
115 if (multimeter_timeval_sub (&time_end, &time_now, &timeout) == -1)
116 break;
118 status = select(fd+1, &rfds, NULL, NULL, &timeout);
120 if (status > 0) /* usually we succeed */
121 {
122 status = read(fd, buf, LINE_LENGTH);
124 if ((status < 0) && ((errno == EAGAIN) || (errno == EINTR)))
125 continue;
127 /* Format: "DC 00.000mV \r" */
128 if (status > 0 && status == LINE_LENGTH)
129 {
130 *value = strtod(buf + 2, &range);
132 if ( range > (buf + 6) )
133 {
134 range = buf + 9;
136 switch ( *range )
137 {
138 case 'p': *value *= 1.0E-12; break;
139 case 'n': *value *= 1.0E-9; break;
140 case 'u': *value *= 1.0E-6; break;
141 case 'm': *value *= 1.0E-3; break;
142 case 'k': *value *= 1.0E3; break;
143 case 'M': *value *= 1.0E6; break;
144 case 'G': *value *= 1.0E9; break;
145 }
146 }
147 else
148 return (-1); /* Overflow */
150 return (0); /* value received */
151 }
152 else break;
153 }
154 else if (!status) /* Timeout */
155 {
156 break;
157 }
158 else if ((status == -1) && ((errno == EAGAIN) || (errno == EINTR)))
159 {
160 continue;
161 }
162 else /* status == -1 */
163 {
164 char errbuf[1024];
165 ERROR ("multimeter plugin: "
166 "select failed: %s",
167 sstrerror (errno, errbuf, sizeof (errbuf)));
168 break;
169 }
170 }
171 } while (--retry);
173 return (-2); /* no value received */
174 } /* int multimeter_read_value */
176 static int multimeter_init (void)
177 {
178 int i;
179 char device[] = "/dev/ttyS ";
181 for (i = 0; i < 10; i++)
182 {
183 device[strlen(device)-1] = i + '0';
185 if ((fd = open(device, O_RDWR | O_NOCTTY)) > 0)
186 {
187 struct termios tios;
188 int rts = TIOCM_RTS;
189 double value;
191 tios.c_cflag = B1200 | CS7 | CSTOPB | CREAD | CLOCAL;
192 tios.c_iflag = IGNBRK | IGNPAR;
193 tios.c_oflag = 0;
194 tios.c_lflag = 0;
195 tios.c_cc[VTIME] = 3;
196 tios.c_cc[VMIN] = LINE_LENGTH;
198 tcflush(fd, TCIFLUSH);
199 tcsetattr(fd, TCSANOW, &tios);
200 ioctl(fd, TIOCMBIC, &rts);
202 if (multimeter_read_value (&value) < -1)
203 {
204 close (fd);
205 fd = -1;
206 }
207 else
208 {
209 INFO ("multimeter plugin: Device "
210 "found at %s", device);
211 return (0);
212 }
213 }
214 }
216 ERROR ("multimeter plugin: No device found");
217 return (-1);
218 }
219 #undef LINE_LENGTH
221 static void multimeter_submit (double value)
222 {
223 value_t values[1];
224 value_list_t vl = VALUE_LIST_INIT;
226 values[0].gauge = value;
228 vl.values = values;
229 vl.values_len = 1;
230 vl.time = time (NULL);
231 strcpy (vl.host, hostname_g);
232 strcpy (vl.plugin, "multimeter");
234 plugin_dispatch_values ("multimeter", &vl);
235 }
237 static int multimeter_read (void)
238 {
239 double value;
241 if (fd < 0)
242 return (-1);
244 if (multimeter_read_value (&value) != 0)
245 return (-1);
247 multimeter_submit (value);
248 return (0);
249 } /* int multimeter_read */
251 static int multimeter_shutdown (void)
252 {
253 if (fd >= 0)
254 {
255 close (fd);
256 fd = -1;
257 }
259 return (0);
260 }
261 #endif /* MULTIMETER_HAVE_READ */
263 void module_register (modreg_e load)
264 {
265 if (load & MR_DATASETS)
266 plugin_register_data_set (&data_set);
268 #if MULTIMETER_HAVE_READ
269 if (load & MR_READ)
270 {
271 plugin_register_init ("multimeter", multimeter_init);
272 plugin_register_read ("multimeter", multimeter_read);
273 plugin_register_shutdown ("multimeter", multimeter_shutdown);
274 }
275 #endif /* MULTIMETER_HAVE_READ */
276 } /* void module_register */