[systemd-devel] [PATCH] timedated: when performing "SetTime" compensate for program lag

[Shawn Landden]

I can't test this as kdbus doesn't build against Linux 3.19
---
 TODO                     |  2 --
 src/timedate/timedated.c | 14 ++++++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/TODO b/TODO
index 93dfa60..88055d3 100644
--- a/TODO
+++ b/TODO
@@ -190,8 +190,6 @@ Features:
 * we should try harder to collapse start jobs for swaps that end up being the same:
   http://lists.freedesktop.org/archives/systemd-devel/2014-November/025359.html
 
-* timedated should compensate on SetTime for the time spent in polkit
-
 * figure out when we can use the coarse timers
 
 * sd-resolve: drop res_query wrapping, people should call via the bus to resolved instead
diff --git a/src/timedate/timedated.c b/src/timedate/timedated.c
index 753c3d1..1287038 100644
--- a/src/timedate/timedated.c
+++ b/src/timedate/timedated.c
@@ -529,6 +529,7 @@ static int method_set_time(sd_bus *bus, sd_bus_message *m, void *userdata, sd_bu
         Context *c = userdata;
         int64_t utc;
         struct timespec ts;
+        usec_t start, ready;
         struct tm* tm;
         int r;
 
@@ -569,6 +570,17 @@ static int method_set_time(sd_bus *bus, sd_bus_message *m, void *userdata, sd_bu
         if (r == 0)
                 return 1;
 
+        /* adjust ts for time spent in program */
+        r = sd_bus_message_get_monotonic_usec(m, &start);
+        if (r == -ENODATA)
+                continue;
+        else if (r < 0)
+                return r;
+        else {
+                ready = now(CLOCK_MONOTONIC);
+                timespec_store(&ts, timespec_load(&ts) + (ready - start));
+        }
+
         /* Set system clock */
         if (clock_settime(CLOCK_REALTIME, &ts) < 0) {
                 log_error_errno(errno, "Failed to set local time: %m");
@@ -702,6 +714,8 @@ int main(int argc, char *argv[]) {
         if (r < 0)
                 goto finish;
 
+        (void)sd_bus_negotiate_timestamp(bus, true);
+
         r = context_read_data(&context);
         if (r < 0) {
                 log_error_errno(r, "Failed to read time zone data: %m");
-- 
2.2.1.209.g41e5f3a