gpssnmp: a simple program to poll gpsd for a few SNMP OID variables.

Signed-off-by: Gary E. Miller <gem@rellim.com>

2 files changed, 92 insertions, 0 deletions

diff --git a/contrib/README b/contrib/README
index 74811000..c060ec29 100644
--- a/contrib/README
+++ b/contrib/README
@@ -2,6 +2,7 @@ The following tools are not production-ready. They are included only as
 conveniences, examples or rudimetary starting points for other development
 efforts.
 
+gpssnmp a tool to return some SNMP values from the running local gpsd.
  
 clock_test is used to test the latency of the system call clock_getttime().
 
diff --git a/contrib/gpssnmp.c b/contrib/gpssnmp.c
new file mode 100644
index 00000000..4b109738
--- /dev/null
+++ b/contrib/gpssnmp.c
@@ -0,0 +1,91 @@
+/* gpssnmp - poll local gpsd for SNMP variables
+ * 
+ * Copyright (c) 2016 David Taylor <gpsd@david.taylor.name>
+ *
+ * Copyright (c)2018 by the GPSD project
+ * SPDX-License-Identifier: BSD-2-clause
+ *
+ * To build this:
+ *     gcc -o gpssnmp gpssnmp.c -lgps
+ *
+ */
+
+#include <gps.h>
+#include <stdio.h>
+#include <string.h>
+
+static void usage() {
+    printf("\n"
+        "Usage:\n"
+        "\n"
+        "to get OID_VISIBLE\n"
+        "   $ gpssnmp -g .1.3.6.1.2.1.25.1.31\n"
+        "   .1.3.6.1.2.1.25.1.31\n"
+        "   gauge\n"
+        "   13\n"
+        "\n"
+        "to get OID_USED\n"
+        "   $ gpssnmp -g .1.3.6.1.2.1.25.1.32\n"
+        "   .1.3.6.1.2.1.25.1.32\n"
+        "   gauge\n"
+        "   4\n"
+        "\n"
+        "to get OID_SNR_AVG\n"
+        "   $ gpssnmp -g .1.3.6.1.2.1.25.1.33\n"
+        "   .1.3.6.1.2.1.25.1.33\n"
+        "   gauge\n"
+        "   22.250000\n"
+        "\n");
+}
+
+int main (int argc, char **argv) {
+  int status, used, visible;
+  struct gps_data_t gpsdata;
+
+  #define OID_VISIBLE ".1.3.6.1.2.1.25.1.31"
+  #define OID_USED ".1.3.6.1.2.1.25.1.32"
+  #define OID_SNR_AVG ".1.3.6.1.2.1.25.1.33"
+
+  if ((argc > 2) && (strcmp ("-g", argv[1]) == 0)) {
+    int i;
+    double snr_total=0;
+    double snr_avg = 0.0;
+
+    status = gps_open (GPSD_SHARED_MEMORY, DEFAULT_GPSD_PORT, &gpsdata);
+    status = gps_read (&gpsdata);
+    used  = gpsdata.satellites_used;
+    visible = gpsdata.satellites_visible;
+    for(i=0; i<=used; i++) {
+        if (gpsdata.skyview[i].used > 0 && gpsdata.skyview[i].ss > 1) {
+//          printf ("i: %d, P:%d, ss: %f\n", i, gpsdata.skyview[i].PRN,
+//                  gpsdata.skyview[i].ss);
+            snr_total+=gpsdata.skyview[i].ss;
+        }
+    }
+    gps_close (&gpsdata);
+    if (used > 0) {
+        snr_avg = snr_total / used;
+    }
+    if (strcmp (OID_VISIBLE, argv[2]) == 0) {
+	printf (OID_VISIBLE);
+	printf ("\n");
+	printf ("gauge\n");
+	printf ("%d\n", visible);
+    }
+    if (strcmp (OID_USED, argv[2]) == 0) {
+	printf (OID_USED);
+	printf ("\n");
+	printf ("gauge\n");
+	printf ("%d\n", used);
+    }
+    if (strcmp (OID_SNR_AVG, argv[2]) == 0) {
+	printf (OID_SNR_AVG);
+	printf ("\n");
+	printf ("gauge\n");
+	printf ("%lf\n", snr_avg);
+    }
+  } else {
+    usage();
+  }
+  return 0;
+}