93ab3d29a31617ba2387c0fbd8d68780879aa604
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
31 #include <sys/ioctl.h>
32 #include <termios.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 int retry = 3; /* sometimes we receive garbadge */
43 do {
44 struct timeval time_end;
46 tcflush(fd, TCIFLUSH);
48 if (gettimeofday(&time_end, NULL) < 0) {
49 char errbuf[1024];
50 ERROR("multimeter plugin: gettimeofday failed: %s",
51 sstrerror(errno, errbuf, sizeof(errbuf)));
52 return (-1);
53 }
54 time_end.tv_sec++;
56 while (1) {
57 char buf[LINE_LENGTH];
58 char *range;
59 int status;
60 fd_set rfds;
61 struct timeval timeout;
62 struct timeval time_now;
64 status = swrite(fd, "D", 1);
65 if (status < 0) {
66 ERROR("multimeter plugin: swrite failed.");
67 return (-1);
68 }
70 FD_ZERO(&rfds);
71 FD_SET(fd, &rfds);
73 if (gettimeofday(&time_now, NULL) < 0) {
74 char errbuf[1024];
75 ERROR("multimeter plugin: "
76 "gettimeofday failed: %s",
77 sstrerror(errno, errbuf, sizeof(errbuf)));
78 return (-1);
79 }
80 if (timeval_cmp(time_end, time_now, &timeout) < 0)
81 break;
83 status = select(fd + 1, &rfds, NULL, NULL, &timeout);
85 if (status > 0) /* usually we succeed */
86 {
87 status = read(fd, buf, LINE_LENGTH);
89 if ((status < 0) && ((errno == EAGAIN) || (errno == EINTR)))
90 continue;
92 /* Format: "DC 00.000mV \r" */
93 if (status > 0 && status == LINE_LENGTH) {
94 *value = strtod(buf + 2, &range);
96 if (range > (buf + 6)) {
97 range = buf + 9;
99 switch (*range) {
100 case 'p':
101 *value *= 1.0E-12;
102 break;
103 case 'n':
104 *value *= 1.0E-9;
105 break;
106 case 'u':
107 *value *= 1.0E-6;
108 break;
109 case 'm':
110 *value *= 1.0E-3;
111 break;
112 case 'k':
113 *value *= 1.0E3;
114 break;
115 case 'M':
116 *value *= 1.0E6;
117 break;
118 case 'G':
119 *value *= 1.0E9;
120 break;
121 }
122 } else
123 return (-1); /* Overflow */
125 return (0); /* value received */
126 } else
127 break;
128 } else if (!status) /* Timeout */
129 {
130 break;
131 } else if ((status == -1) && ((errno == EAGAIN) || (errno == EINTR))) {
132 continue;
133 } else /* status == -1 */
134 {
135 char errbuf[1024];
136 ERROR("multimeter plugin: "
137 "select failed: %s",
138 sstrerror(errno, errbuf, sizeof(errbuf)));
139 break;
140 }
141 }
142 } while (--retry);
144 return (-2); /* no value received */
145 } /* int multimeter_read_value */
147 static int multimeter_init(void) {
148 char device[] = "/dev/ttyS ";
150 for (int i = 0; i < 10; i++) {
151 device[strlen(device) - 1] = i + '0';
153 if ((fd = open(device, O_RDWR | O_NOCTTY)) != -1) {
154 struct termios tios = {0};
155 int rts = TIOCM_RTS;
156 double value;
158 tios.c_cflag = B1200 | CS7 | CSTOPB | CREAD | CLOCAL;
159 tios.c_iflag = IGNBRK | IGNPAR;
160 tios.c_oflag = 0;
161 tios.c_lflag = 0;
162 tios.c_cc[VTIME] = 3;
163 tios.c_cc[VMIN] = LINE_LENGTH;
165 tcflush(fd, TCIFLUSH);
166 tcsetattr(fd, TCSANOW, &tios);
167 ioctl(fd, TIOCMBIC, &rts);
169 if (multimeter_read_value(&value) < -1) {
170 close(fd);
171 fd = -1;
172 } else {
173 INFO("multimeter plugin: Device "
174 "found at %s",
175 device);
176 return (0);
177 }
178 }
179 }
181 ERROR("multimeter plugin: No device found");
182 return (-1);
183 }
184 #undef LINE_LENGTH
186 static void multimeter_submit(double value) {
187 value_list_t vl = VALUE_LIST_INIT;
189 vl.values = &(value_t){.gauge = value};
190 vl.values_len = 1;
191 sstrncpy(vl.plugin, "multimeter", sizeof(vl.plugin));
192 sstrncpy(vl.type, "multimeter", sizeof(vl.type));
194 plugin_dispatch_values(&vl);
195 }
197 static int multimeter_read(void) {
198 double value;
200 if (fd < 0)
201 return (-1);
203 if (multimeter_read_value(&value) != 0)
204 return (-1);
206 multimeter_submit(value);
207 return (0);
208 } /* int multimeter_read */
210 static int multimeter_shutdown(void) {
211 if (fd >= 0) {
212 close(fd);
213 fd = -1;
214 }
216 return (0);
217 }
219 void module_register(void) {
220 plugin_register_init("multimeter", multimeter_init);
221 plugin_register_read("multimeter", multimeter_read);
222 plugin_register_shutdown("multimeter", multimeter_shutdown);
223 } /* void module_register */