+/**
+ * collectd - src/multimeter.c
+ * Copyright (C) 2005,2006 Peter Holik
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Authors:
+ * Peter Holik <peter at holik.at>
+ *
+ * Used multimeter: Metex M-4650CR
+ *
+ **/
+
+#include <termios.h>
+#include <sys/ioctl.h>
+#include <math.h>
+#include "collectd.h"
+#include "common.h"
+#include "plugin.h"
+
+#define MODULE_NAME "multimeter"
+
+static char *multimeter_file = "multimeter.rrd";
+
+static char *ds_def[] =
+{
+ "DS:value:GAUGE:"COLLECTD_HEARTBEAT":U:U",
+ NULL
+};
+static int ds_num = 1;
+
+static int fd = -1;
+
+static int multimeter_timeval_sub (struct timeval *tv1, struct timeval *tv2,
+ struct timeval *res)
+{
+ if ((tv1->tv_sec < tv2->tv_sec) ||
+ ((tv1->tv_sec == tv2->tv_sec) && (tv1->tv_usec < tv2->tv_usec)))
+ return (-1);
+
+ res->tv_sec = tv1->tv_sec - tv2->tv_sec;
+ res->tv_usec = tv1->tv_usec - tv2->tv_usec;
+
+ assert ((res->tv_sec > 0) || ((res->tv_sec == 0) && (res->tv_usec > 0)));
+
+ while (res->tv_usec < 0)
+ {
+ res->tv_usec += 1000000;
+ res->tv_sec--;
+ }
+ return (0);
+}
+#define LINE_LENGTH 14
+static int multimeter_read_value(double *value)
+{
+ int retry = 3; /* sometimes we receive garbadge */
+
+ do
+ {
+ struct timeval time_end;
+
+ tcflush(fd, TCIFLUSH);
+
+ if (gettimeofday (&time_end, NULL) < 0)
+ {
+ syslog (LOG_ERR, MODULE_NAME": gettimeofday failed: %s",
+ strerror (errno));
+ return (-1);
+ }
+ time_end.tv_sec++;
+
+ while (1)
+ {
+ char buf[LINE_LENGTH];
+ char *range;
+ int status;
+ fd_set rfds;
+ struct timeval timeout;
+ struct timeval time_now;
+
+ write(fd, "D", 1);
+
+ FD_ZERO(&rfds);
+ FD_SET(fd, &rfds);
+
+ if (gettimeofday (&time_now, NULL) < 0)
+ {
+ syslog (LOG_ERR, MODULE_NAME": gettimeofday failed: %s",
+ strerror (errno));
+ return (-1);
+ }
+ if (multimeter_timeval_sub (&time_end, &time_now, &timeout) == -1)
+ break;
+
+ status = select(fd+1, &rfds, NULL, NULL, &timeout);
+
+ if (status > 0) /* usually we succeed */
+ {
+ status = read(fd, buf, LINE_LENGTH);
+
+ if ((status < 0) && ((errno == EAGAIN) || (errno == EINTR)))
+ continue;
+
+ /* Format: "DC 00.000mV \r" */
+ if (status > 0 && status == LINE_LENGTH)
+ {
+ *value = strtod(buf + 2, &range);
+
+ if ( range > (buf + 6) )
+ {
+ range = buf + 9;
+
+ switch ( *range )
+ {
+ case 'p': *value *= 1.0E-12; break;
+ case 'n': *value *= 1.0E-9; break;
+ case 'u': *value *= 1.0E-6; break;
+ case 'm': *value *= 1.0E-3; break;
+ case 'k': *value *= 1.0E3; break;
+ case 'M': *value *= 1.0E6; break;
+ case 'G': *value *= 1.0E9; break;
+ }
+ }
+ else
+ return (-1); /* Overflow */
+
+ return (0); /* value received */
+ }
+ else break;
+ }
+ else if (!status) /* Timeout */
+ {
+ break;
+ }
+ else if ((status == -1) && ((errno == EAGAIN) || (errno == EINTR)))
+ {
+ continue;
+ }
+ else /* status == -1 */
+ {
+ syslog (LOG_ERR, MODULE_NAME": select failed: %s",
+ strerror (errno));
+ break;
+ }
+ }
+ } while (--retry);
+
+ return (-2); /* no value received */
+}
+
+static void multimeter_init (void)
+{
+ int i;
+ char device[] = "/dev/ttyS ";
+
+ for (i = 0; i < 10; i++)
+ {
+ device[strlen(device)-1] = i + '0';
+
+ if ((fd = open(device, O_RDWR | O_NOCTTY)) > 0)
+ {
+ struct termios tios;
+ int rts = TIOCM_RTS;
+ double value;
+
+ tios.c_cflag = B1200 | CS7 | CSTOPB | CREAD | CLOCAL;
+ tios.c_iflag = IGNBRK | IGNPAR;
+ tios.c_oflag = 0;
+ tios.c_lflag = 0;
+ tios.c_cc[VTIME] = 3;
+ tios.c_cc[VMIN] = LINE_LENGTH;
+
+ tcflush(fd, TCIFLUSH);
+ tcsetattr(fd, TCSANOW, &tios);
+ ioctl(fd, TIOCMBIC, &rts);
+
+ if (multimeter_read_value(&value) < -1)
+ {
+ close(fd);
+ fd = -1;
+ }
+ else
+ {
+ syslog (LOG_INFO, MODULE_NAME" found (%s)", device);
+ return;
+ }
+ }
+ }
+ syslog (LOG_ERR, MODULE_NAME" not found");
+}
+#undef LINE_LENGTH
+
+static void multimeter_write (char *host, char *inst, char *val)
+{
+ rrd_update_file (host, multimeter_file, val, ds_def, ds_num);
+}
+#define BUFSIZE 128
+static void multimeter_submit (double *value)
+{
+ char buf[BUFSIZE];
+
+ if (snprintf (buf, BUFSIZE, "%u:%f", (unsigned int) curtime, *value) >= BUFSIZE)
+ return;
+
+ plugin_submit (MODULE_NAME, NULL, buf);
+}
+#undef BUFSIZE
+
+static void multimeter_read (void)
+{
+ double value;
+
+ if (fd > -1 && !(multimeter_read_value(&value)))
+ multimeter_submit (&value);
+}
+
+void module_register (void)
+{
+ plugin_register (MODULE_NAME, multimeter_init, multimeter_read, multimeter_write);
+}
+
+#undef MODULE_NAME