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authorDenys Vlasenko2010-01-25 19:30:16 +0100
committerDenys Vlasenko2010-01-25 19:30:16 +0100
commit24928ffd8d6eb7f410ea0a7b4530086cecfeea6e (patch)
treefa0c4b0cdcebb2c4a9f8d5aefcd42fcafcbb89da /examples/var_service/ntpd
parent3581c625151d25d8e1cbc80c44337d398d97cf42 (diff)
downloadbusybox-24928ffd8d6eb7f410ea0a7b4530086cecfeea6e.zip
busybox-24928ffd8d6eb7f410ea0a7b4530086cecfeea6e.tar.gz
ntpd: explain why scripts can be run in quick succession
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'examples/var_service/ntpd')
-rwxr-xr-xexamples/var_service/ntpd/ntp.script20
1 files changed, 14 insertions, 6 deletions
diff --git a/examples/var_service/ntpd/ntp.script b/examples/var_service/ntpd/ntp.script
index 90299ae..76c34bf 100755
--- a/examples/var_service/ntpd/ntp.script
+++ b/examples/var_service/ntpd/ntp.script
@@ -1,10 +1,12 @@
#!/bin/sh
-exec 2>/dev/null
-echo "`tail -n 99 "$0.log"`" >"$0.log"
-
-exec >>"$0.log"
-exec 2>&1
+# Note that there is no provision to prevent several copies of the script
+# to be run in quick succession. In fact, it happens rather often
+# if initial syncronization results in a step.
+# You will see "step" and then "stratum" script runs, sometimes
+# as close as only 0.002 seconds apart.
+#
+# Script should be ready to deal with this.
dt=`date '+%Y-%m-%d %H:%M:%S'`
@@ -13,17 +15,23 @@ if test x"$stratum" != x"" \
&& test 4 -ge "$stratum" \
&& test 128 -le "$poll_interval" \
; then
+ echo "`tail -n 199 -- "$0.log" 2>/dev/null`" >"$0.log.$$"
echo "$dt: $1"\
"freq_drift_ppm=$freq_drift_ppm"\
"offset=$offset"\
"stratum=$stratum"\
"poll_interval=$poll_interval,"\
- "setting hardware clock"
+ "setting hardware clock"\
+ >>"$0.log.$$"
+ mv -- "$0.log.$$" "$0.log"
exec hwclock --systohc
fi
+echo "`tail -n 199 -- "$0.log" 2>/dev/null`" >"$0.log.$$"
echo "$dt: $1"\
"freq_drift_ppm=$freq_drift_ppm"\
"offset=$offset"\
"stratum=$stratum"\
"poll_interval=$poll_interval"\
+ >>"$0.log.$$"
+mv -- "$0.log.$$" "$0.log"