ntpd: add -S PROG option. This feature is crucial for CMOS/RTC syncronization

function                                             old     new   delta
run_script                                           112     278    +166
ntpd_main                                            779     825     +46
update_local_clock                                   824     858     +34
packed_usage                                       26518   26540     +22
ntp_init                                             366     371      +5
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/0 up/down: 273/0)             Total: 273 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 55 insertions, 6 deletions

diff --git a/networking/ntpd.c b/networking/ntpd.c
index ab1c58c97..81474547e 100644
--- a/networking/ntpd.c
+++ b/networking/ntpd.c
@@ -194,7 +194,8 @@ enum {
         /* Non-compat options: */
         OPT_w = (1 << 4),
         OPT_p = (1 << 5),
-        OPT_l = (1 << 6) * ENABLE_FEATURE_NTPD_SERVER,
+        OPT_S = (1 << 6),
+        OPT_l = (1 << 7) * ENABLE_FEATURE_NTPD_SERVER,
 };
 
 struct globals {
@@ -205,6 +206,9 @@ struct globals {
         double   reftime;
         /* total dispersion to currently selected reference clock */
         double   rootdisp;
+
+        double   last_script_run;
+        char     *script_name;
         llist_t  *ntp_peers;
 #if ENABLE_FEATURE_NTPD_SERVER
         int      listen_fd;
@@ -682,6 +686,38 @@ send_query_to_peer(peer_t *p)
 }
 
 
+static void run_script(const char *action)
+{
+        char *argv[3];
+        char *env1, *env2;
+
+        if (!G.script_name)
+                return;
+
+        argv[0] = (char*) G.script_name;
+        argv[1] = (char*) action;
+        argv[2] = NULL;
+
+        VERB1 bb_error_msg("executing '%s %s'", G.script_name, action);
+
+        env1 = xasprintf("stratum=%u", G.stratum);
+        putenv(env1);
+        env2 = xasprintf("freq_drift_ppm=%ld", G.kernel_freq_drift);
+        putenv(env2);
+        /* Other items of potential interest: selected peer,
+         * rootdelay, reftime, rootdisp, refid, ntp_status, poll_exp,
+         * last_update_offset, last_update_recv_time, discipline_jitter
+         */
+
+        wait4pid(spawn(argv));
+        G.last_script_run = G.cur_time;
+
+        unsetenv("stratum");
+        unsetenv("freq_drift_ppm");
+        free(env1);
+        free(env2);
+}
+
 static NOINLINE void
 step_time(double offset)
 {
@@ -1140,6 +1176,9 @@ update_local_clock(peer_t *p)
                 G.polladj_count = 0;
                 G.poll_exp = MINPOLL;
                 G.stratum = MAXSTRAT;
+
+                run_script("step");
+
                 if (G.discipline_state == STATE_NSET) {
                         set_new_values(STATE_FREQ, /*offset:*/ 0, recv_time);
                         return 1; /* "ok to increase poll interval" */
@@ -1225,7 +1264,10 @@ update_local_clock(peer_t *p)
                         set_new_values(STATE_SYNC, offset, recv_time);
                         break;
                 }
-                G.stratum = p->lastpkt_stratum + 1;
+                if (G.stratum != p->lastpkt_stratum + 1) {
+                        G.stratum = p->lastpkt_stratum + 1;
+                        run_script("stratum");
+                }
         }
 
         G.reftime = G.cur_time;
@@ -1729,17 +1771,17 @@ static NOINLINE void ntp_init(char **argv)
         G.stratum = MAXSTRAT;
         if (BURSTPOLL != 0)
                 G.poll_exp = BURSTPOLL; /* speeds up initial sync */
-        G.reftime = G.last_update_recv_time = gettime1900d(); /* sets G.cur_time too */
+        G.last_script_run = G.reftime = G.last_update_recv_time = gettime1900d(); /* sets G.cur_time too */
 
         /* Parse options */
         peers = NULL;
         opt_complementary = "dd:p::wn"; /* d: counter; p: list; -w implies -n */
         opts = getopt32(argv,
                         "nqNx" /* compat */
-                        "wp:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
+                        "wp:S:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
                         "d" /* compat */
                         "46aAbgL", /* compat, ignored */
-                        &peers, &G.verbose);
+                        &peers, &G.script_name, &G.verbose);
         if (!(opts & (OPT_p|OPT_l)))
                 bb_show_usage();
 //      if (opts & OPT_x) /* disable stepping, only slew is allowed */
@@ -1854,8 +1896,15 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
                 VERB2 bb_error_msg("poll %us, sockets:%u", timeout, i);
                 nfds = poll(pfd, i, timeout * 1000);
                 gettime1900d(); /* sets G.cur_time */
-                if (nfds <= 0)
+                if (nfds <= 0) {
+                        if (G.adjtimex_was_done
+                         && G.cur_time - G.last_script_run > 11*60
+                        ) {
+                                /* Useful for updating battery-backed RTC and such */
+                                run_script("periodic");
+                        }
                         continue;
+                }
 
                 /* Process any received packets */
                 j = 0;