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