diff options
Diffstat (limited to 'libntp/systime.c')
| -rw-r--r-- | libntp/systime.c | 57 |
1 files changed, 39 insertions, 18 deletions
diff --git a/libntp/systime.c b/libntp/systime.c index ac6aa983f7b5d..4539b5fec3ce4 100644 --- a/libntp/systime.c +++ b/libntp/systime.c @@ -9,9 +9,11 @@ #include "ntp_syslog.h" #include "ntp_unixtime.h" #include "ntp_stdlib.h" +#include "ntp_random.h" +#include "ntpd.h" /* for sys_precision */ #ifdef SIM -#include "ntpsim.h" +# include "ntpsim.h" #endif /*SIM */ #ifdef HAVE_SYS_PARAM_H @@ -33,11 +35,15 @@ * made to minimize errors by always rounding toward zero and amortizing * adjustment residues. By default the adjustment quantum is 1 us for * the usual Unix tickadj() system call, but this can be increased if - * necessary by a configuration command. For instance, when the + * necessary by the tick configuration command. For instance, when the * adjtime() quantum is a clock tick for a 100-Hz clock, the quantum * should be 10 ms. */ -double sys_tick = 1e-6; /* tickadj() quantum (s) */ +#if defined RELIANTUNIX_CLOCK || defined SCO5_CLOCK +double sys_tick = 10e-3; /* 10 ms tickadj() */ +#else +double sys_tick = 1e-6; /* 1 us tickadj() */ +#endif double sys_residual = 0; /* adjustment residue (s) */ #ifndef SIM @@ -57,6 +63,8 @@ get_systime( /* * Convert Unix clock from seconds and nanoseconds to seconds. + * The bottom is only two bits down, so no need for fuzz. + * Some systems don't have that level of precision, however... */ # ifdef HAVE_CLOCK_GETTIME clock_gettime(CLOCK_REALTIME, &ts); @@ -71,6 +79,7 @@ get_systime( /* * Convert Unix clock from seconds and microseconds to seconds. + * Add in unbiased random fuzz beneath the microsecond. */ GETTIMEOFDAY(&tv, NULL); now->l_i = tv.tv_sec + JAN_1970; @@ -79,13 +88,22 @@ get_systime( #endif /* HAVE_CLOCK_GETTIME || HAVE_GETCLOCK */ /* + * ntp_random() produces 31 bits (always nonnegative). + * This bit is done only after the precision has been + * determined. + */ + if (sys_precision != 0) + dtemp += (ntp_random() / FRAC - .5) / (1 << + -sys_precision); + + /* * Renormalize to seconds past 1900 and fraction. */ dtemp += sys_residual; if (dtemp >= 1) { dtemp -= 1; now->l_i++; - } else if (dtemp < -1) { + } else if (dtemp < 0) { dtemp += 1; now->l_i--; } @@ -135,10 +153,13 @@ adj_systime( if (isneg) { adjtv.tv_sec = -adjtv.tv_sec; adjtv.tv_usec = -adjtv.tv_usec; + sys_residual = -sys_residual; } - if (adjtime(&adjtv, &oadjtv) < 0) { - msyslog(LOG_ERR, "adj_systime: %m"); - return (0); + if (adjtv.tv_sec != 0 || adjtv.tv_usec != 0) { + if (adjtime(&adjtv, &oadjtv) < 0) { + msyslog(LOG_ERR, "adj_systime: %m"); + return (0); + } } return (1); } @@ -173,11 +194,11 @@ step_systime( (double)adjtv.tv_sec) * 1e6 + .5); } #if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_GETCLOCK) -#ifdef HAVE_CLOCK_GETTIME +# ifdef HAVE_CLOCK_GETTIME (void) clock_gettime(CLOCK_REALTIME, &ts); -#else +# else (void) getclock(TIMEOFDAY, &ts); -#endif +# endif timetv.tv_sec = ts.tv_sec; timetv.tv_usec = ts.tv_nsec / 1000; #else /* not HAVE_GETCLOCK */ @@ -406,13 +427,8 @@ adj_systime( adjtv.tv_usec = -adjtv.tv_usec; sys_residual = -sys_residual; } - - /* - * We went to all the trouble just to be sure the emulation is - * precise. We now return to our regularly scheduled concert. - */ - ntp_node.clk_time -= adjtv.tv_sec + adjtv.tv_usec / 1e6; - return (1); + ntp_node.adj = now; + return (1); } @@ -424,7 +440,12 @@ step_systime( double now /* step adjustment (s) */ ) { - ntp_node.adj = now; +#ifdef DEBUG + if (debug) + printf("step_systime: time %.6f adj %.6f\n", + ntp_node.ntp_time, now); +#endif + ntp_node.ntp_time += now; return (1); } |