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 #define LINE_LENGTH 14
40 static int multimeter_read_value(double *value)
41 {
42 int retry = 3; /* sometimes we receive garbadge */
44 do
45 {
46 struct timeval time_end;
48 tcflush(fd, TCIFLUSH);
50 if (gettimeofday (&time_end, NULL) < 0)
51 {
52 char errbuf[1024];
53 ERROR ("multimeter plugin: gettimeofday failed: %s",
54 sstrerror (errno, errbuf,
55 sizeof (errbuf)));
56 return (-1);
57 }
58 time_end.tv_sec++;
60 while (1)
61 {
62 char buf[LINE_LENGTH];
63 char *range;
64 int status;
65 fd_set rfds;
66 struct timeval timeout;
67 struct timeval time_now;
69 status = swrite (fd, "D", 1);
70 if (status < 0)
71 {
72 ERROR ("multimeter plugin: swrite failed.");
73 return (-1);
74 }
76 FD_ZERO(&rfds);
77 FD_SET(fd, &rfds);
79 if (gettimeofday (&time_now, NULL) < 0)
80 {
81 char errbuf[1024];
82 ERROR ("multimeter plugin: "
83 "gettimeofday failed: %s",
84 sstrerror (errno, errbuf,
85 sizeof (errbuf)));
86 return (-1);
87 }
88 if (timeval_cmp (time_end, time_now, &timeout) < 0)
89 break;
91 status = select(fd+1, &rfds, NULL, NULL, &timeout);
93 if (status > 0) /* usually we succeed */
94 {
95 status = read(fd, buf, LINE_LENGTH);
97 if ((status < 0) && ((errno == EAGAIN) || (errno == EINTR)))
98 continue;
100 /* Format: "DC 00.000mV \r" */
101 if (status > 0 && status == LINE_LENGTH)
102 {
103 *value = strtod(buf + 2, &range);
105 if ( range > (buf + 6) )
106 {
107 range = buf + 9;
109 switch ( *range )
110 {
111 case 'p': *value *= 1.0E-12; break;
112 case 'n': *value *= 1.0E-9; break;
113 case 'u': *value *= 1.0E-6; break;
114 case 'm': *value *= 1.0E-3; break;
115 case 'k': *value *= 1.0E3; break;
116 case 'M': *value *= 1.0E6; break;
117 case 'G': *value *= 1.0E9; break;
118 }
119 }
120 else
121 return (-1); /* Overflow */
123 return (0); /* value received */
124 }
125 else break;
126 }
127 else if (!status) /* Timeout */
128 {
129 break;
130 }
131 else if ((status == -1) && ((errno == EAGAIN) || (errno == EINTR)))
132 {
133 continue;
134 }
135 else /* status == -1 */
136 {
137 char errbuf[1024];
138 ERROR ("multimeter plugin: "
139 "select failed: %s",
140 sstrerror (errno, errbuf, sizeof (errbuf)));
141 break;
142 }
143 }
144 } while (--retry);
146 return (-2); /* no value received */
147 } /* int multimeter_read_value */
149 static int multimeter_init (void)
150 {
151 int i;
152 char device[] = "/dev/ttyS ";
154 for (i = 0; i < 10; i++)
155 {
156 device[strlen(device)-1] = i + '0';
158 if ((fd = open(device, O_RDWR | O_NOCTTY)) > 0)
159 {
160 struct termios tios;
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);
191 }
192 #undef LINE_LENGTH
194 static void multimeter_submit (double value)
195 {
196 value_t values[1];
197 value_list_t vl = VALUE_LIST_INIT;
199 values[0].gauge = value;
201 vl.values = values;
202 vl.values_len = 1;
203 sstrncpy (vl.host, hostname_g, sizeof (vl.host));
204 sstrncpy (vl.plugin, "multimeter", sizeof (vl.plugin));
205 sstrncpy (vl.type, "multimeter", sizeof (vl.type));
207 plugin_dispatch_values (&vl);
208 }
210 static int multimeter_read (void)
211 {
212 double value;
214 if (fd < 0)
215 return (-1);
217 if (multimeter_read_value (&value) != 0)
218 return (-1);
220 multimeter_submit (value);
221 return (0);
222 } /* int multimeter_read */
224 static int multimeter_shutdown (void)
225 {
226 if (fd >= 0)
227 {
228 close (fd);
229 fd = -1;
230 }
232 return (0);
233 }
235 void module_register (void)
236 {
237 plugin_register_init ("multimeter", multimeter_init);
238 plugin_register_read ("multimeter", multimeter_read);
239 plugin_register_shutdown ("multimeter", multimeter_shutdown);
240 } /* void module_register */