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 **/
26 #include <termios.h>
27 #include <sys/ioctl.h>
28 #include <math.h>
29 #include "collectd.h"
30 #include "common.h"
31 #include "plugin.h"
33 #define MODULE_NAME "multimeter"
35 static char *multimeter_file = "multimeter.rrd";
37 static char *ds_def[] =
38 {
39 "DS:value:GAUGE:"COLLECTD_HEARTBEAT":U:U",
40 NULL
41 };
42 static int ds_num = 1;
44 static int fd = -1;
46 static int multimeter_timeval_sub (struct timeval *tv1, struct timeval *tv2,
47 struct timeval *res)
48 {
49 if ((tv1->tv_sec < tv2->tv_sec) ||
50 ((tv1->tv_sec == tv2->tv_sec) && (tv1->tv_usec < tv2->tv_usec)))
51 return (-1);
53 res->tv_sec = tv1->tv_sec - tv2->tv_sec;
54 res->tv_usec = tv1->tv_usec - tv2->tv_usec;
56 assert ((res->tv_sec > 0) || ((res->tv_sec == 0) && (res->tv_usec > 0)));
58 while (res->tv_usec < 0)
59 {
60 res->tv_usec += 1000000;
61 res->tv_sec--;
62 }
63 return (0);
64 }
65 #define LINE_LENGTH 14
66 static int multimeter_read_value(double *value)
67 {
68 int retry = 3; /* sometimes we receive garbadge */
70 do
71 {
72 struct timeval time_end;
74 tcflush(fd, TCIFLUSH);
76 if (gettimeofday (&time_end, NULL) < 0)
77 {
78 syslog (LOG_ERR, MODULE_NAME": gettimeofday failed: %s",
79 strerror (errno));
80 return (-1);
81 }
82 time_end.tv_sec++;
84 while (1)
85 {
86 char buf[LINE_LENGTH];
87 char *range;
88 int status;
89 fd_set rfds;
90 struct timeval timeout;
91 struct timeval time_now;
93 write(fd, "D", 1);
95 FD_ZERO(&rfds);
96 FD_SET(fd, &rfds);
98 if (gettimeofday (&time_now, NULL) < 0)
99 {
100 syslog (LOG_ERR, MODULE_NAME": gettimeofday failed: %s",
101 strerror (errno));
102 return (-1);
103 }
104 if (multimeter_timeval_sub (&time_end, &time_now, &timeout) == -1)
105 break;
107 status = select(fd+1, &rfds, NULL, NULL, &timeout);
109 if (status > 0) /* usually we succeed */
110 {
111 status = read(fd, buf, LINE_LENGTH);
113 if ((status < 0) && ((errno == EAGAIN) || (errno == EINTR)))
114 continue;
116 /* Format: "DC 00.000mV \r" */
117 if (status > 0 && status == LINE_LENGTH)
118 {
119 *value = strtod(buf + 2, &range);
121 if ( range > (buf + 6) )
122 {
123 range = buf + 9;
125 switch ( *range )
126 {
127 case 'p': *value *= 1.0E-12; break;
128 case 'n': *value *= 1.0E-9; break;
129 case 'u': *value *= 1.0E-6; break;
130 case 'm': *value *= 1.0E-3; break;
131 case 'k': *value *= 1.0E3; break;
132 case 'M': *value *= 1.0E6; break;
133 case 'G': *value *= 1.0E9; break;
134 }
135 }
136 else
137 return (-1); /* Overflow */
139 return (0); /* value received */
140 }
141 else break;
142 }
143 else if (!status) /* Timeout */
144 {
145 break;
146 }
147 else if ((status == -1) && ((errno == EAGAIN) || (errno == EINTR)))
148 {
149 continue;
150 }
151 else /* status == -1 */
152 {
153 syslog (LOG_ERR, MODULE_NAME": select failed: %s",
154 strerror (errno));
155 break;
156 }
157 }
158 } while (--retry);
160 return (-2); /* no value received */
161 }
163 static void multimeter_init (void)
164 {
165 int i;
166 char device[] = "/dev/ttyS ";
168 for (i = 0; i < 10; i++)
169 {
170 device[strlen(device)-1] = i + '0';
172 if ((fd = open(device, O_RDWR | O_NOCTTY)) > 0)
173 {
174 struct termios tios;
175 int rts = TIOCM_RTS;
176 double value;
178 tios.c_cflag = B1200 | CS7 | CSTOPB | CREAD | CLOCAL;
179 tios.c_iflag = IGNBRK | IGNPAR;
180 tios.c_oflag = 0;
181 tios.c_lflag = 0;
182 tios.c_cc[VTIME] = 3;
183 tios.c_cc[VMIN] = LINE_LENGTH;
185 tcflush(fd, TCIFLUSH);
186 tcsetattr(fd, TCSANOW, &tios);
187 ioctl(fd, TIOCMBIC, &rts);
189 if (multimeter_read_value(&value) < -1)
190 {
191 close(fd);
192 fd = -1;
193 }
194 else
195 {
196 syslog (LOG_INFO, MODULE_NAME" found (%s)", device);
197 return;
198 }
199 }
200 }
201 syslog (LOG_ERR, MODULE_NAME" not found");
202 }
203 #undef LINE_LENGTH
205 static void multimeter_write (char *host, char *inst, char *val)
206 {
207 rrd_update_file (host, multimeter_file, val, ds_def, ds_num);
208 }
209 #define BUFSIZE 128
210 static void multimeter_submit (double *value)
211 {
212 char buf[BUFSIZE];
214 if (snprintf (buf, BUFSIZE, "%u:%f", (unsigned int) curtime, *value) >= BUFSIZE)
215 return;
217 plugin_submit (MODULE_NAME, NULL, buf);
218 }
219 #undef BUFSIZE
221 static void multimeter_read (void)
222 {
223 double value;
225 if (fd > -1 && !(multimeter_read_value(&value)))
226 multimeter_submit (&value);
227 }
229 void module_register (void)
230 {
231 plugin_register (MODULE_NAME, multimeter_init, multimeter_read, multimeter_write);
232 }
234 #undef MODULE_NAME