[gpsd-dev] [PATCH] [RFC] gpsmon: add PPS monitoring at -D2 debug level

[Beat Bolli]

This is a request for comment for adding PPS output to gpsmon, as seen
on Eric's TODO list.

The patch works, but has two issues, IMO. Both are marked with "FIXME"
in the source:

- I'm not sure about updating device->last_fixtime where it is now. It
  works but maybe there's a better place?

- An allocated SHM segment has to be faked, otherwise
  pps_thread_activate() won't even start the thread.

A different issue is whether it's OK to output the PPS messages only at
-D2. Should they be visible at any debug level?

Comments are welcome!

Signed-off-by: Beat Bolli <address@hidden>
---
 gpsmon.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/gpsmon.c b/gpsmon.c
index b415560..7b50b8b 100644
--- a/gpsmon.c
+++ b/gpsmon.c
@@ -775,7 +775,10 @@ static void gpsmon_hook(struct gps_device_t *device, 
gps_mask_t changed UNUSED)
        (void)wnoutrefresh(packetwin);
 
     (void)doupdate();
- 
+
+    /* Update the last fix time seen for PPS. FIXME: do this here? */
+    device->last_fixtime = device->newdata.time;
+
     if (logfile != NULL && device->packet.outbuflen > 0) {
         /*@ -shiftimplementation -sefparams +charint @*/
         assert(fwrite
@@ -784,7 +787,17 @@ static void gpsmon_hook(struct gps_device_t *device, 
gps_mask_t changed UNUSED)
         /*@ +shiftimplementation +sefparams -charint @*/
     }
 }
-   /address@hidden +nullpass address@hidden/
+/address@hidden +nullpass address@hidden/
+
+/* The PPS thread_report_hook callback. This or a pps_hook callback is
+ * needed to keep the PPS thread running.
+ */
+static char *pps_report(struct gps_device_t *session UNUSED,
+                       struct timeval *actual_tv UNUSED,
+                       struct timespec *ts UNUSED,
+                       double edge_offset UNUSED) {
+   return "";
+}
 
 static jmp_buf assertbuf;
 
@@ -961,6 +974,11 @@ int main(int argc, char **argv)
        }
 
        serial = true;
+
+       /* Setup PPS monitoring. */
+       session.shmTimeP = 0;   /* FIXME: fake one allocated SHM segment */
+       session.thread_report_hook = pps_report;
+       pps_thread_activate(&session);
     }
     /*@ +boolops */
     /*@ +nullpass +branchstate @*/
@@ -1051,6 +1069,11 @@ int main(int argc, char **argv)
 
   quit:
     /* we'll fall through to here on longjmp() */
+
+    /* Shut down PPS monitoring. */
+    if (serial)
+       (void)pps_thread_deactivate(&session);
+
     gpsd_close(&session);
     if (logfile)
        (void)fclose(logfile);
-- 
1.8.4.rc3