diff options
Diffstat (limited to 'contrib/ntp/libntp/systime.c')
| -rw-r--r-- | contrib/ntp/libntp/systime.c | 338 |
1 files changed, 211 insertions, 127 deletions
diff --git a/contrib/ntp/libntp/systime.c b/contrib/ntp/libntp/systime.c index 29f1e86..8e70897 100644 --- a/contrib/ntp/libntp/systime.c +++ b/contrib/ntp/libntp/systime.c @@ -5,8 +5,10 @@ * */ #include <config.h> +#include <math.h> #include "ntp.h" +#include "ntpd.h" #include "ntp_syslog.h" #include "ntp_stdlib.h" #include "ntp_random.h" @@ -14,6 +16,7 @@ #include "timevalops.h" #include "timespecops.h" #include "ntp_calendar.h" +#include "lib_strbuf.h" #ifdef HAVE_SYS_PARAM_H # include <sys/param.h> @@ -28,6 +31,9 @@ int allow_panic = FALSE; /* allow panic correction (-g) */ int enable_panic_check = TRUE; /* Can we check allow_panic's state? */ +u_long sys_lamport; /* Lamport violation */ +u_long sys_tsrounding; /* timestamp rounding errors */ + #ifndef USE_COMPILETIME_PIVOT # define USE_COMPILETIME_PIVOT 1 #endif @@ -110,7 +116,10 @@ set_sys_fuzz( sys_fuzz = fuzz_val; INSIST(sys_fuzz >= 0); INSIST(sys_fuzz <= 1.0); - sys_fuzz_nsec = (long)(sys_fuzz * 1e9 + 0.5); + /* [Bug 3450] ensure nsec fuzz >= sys_fuzz to reduce chance of + * short-falling fuzz advance + */ + sys_fuzz_nsec = (long)ceil(sys_fuzz * 1e9); } @@ -168,13 +177,10 @@ get_systime( static struct timespec ts_last; /* last sampled os time */ static struct timespec ts_prev; /* prior os time */ static l_fp lfp_prev; /* prior result */ - static double dfuzz_prev; /* prior fuzz */ struct timespec ts; /* seconds and nanoseconds */ struct timespec ts_min; /* earliest permissible */ struct timespec ts_lam; /* lamport fictional increment */ - struct timespec ts_prev_log; /* for msyslog only */ double dfuzz; - double ddelta; l_fp result; l_fp lfpfuzz; l_fp lfpdelta; @@ -191,8 +197,10 @@ get_systime( * introduce small steps backward. It should not be an issue on * systems where get_ostime() results in a true syscall.) */ - if (cmp_tspec(add_tspec_ns(ts, 50000000), ts_last) < 0) + if (cmp_tspec(add_tspec_ns(ts, 50000000), ts_last) < 0) { lamport_violated = 1; + sys_lamport++; + } ts_last = ts; /* @@ -216,21 +224,16 @@ get_systime( if (!lamport_violated) ts = ts_min; } - ts_prev_log = ts_prev; ts_prev = ts; - } else { - /* - * Quiet "ts_prev_log.tv_sec may be used uninitialized" - * warning from x86 gcc 4.5.2. - */ - ZERO(ts_prev_log); } /* convert from timespec to l_fp fixed-point */ result = tspec_stamp_to_lfp(ts); /* - * Add in the fuzz. + * Add in the fuzz. 'ntp_random()' returns [0..2**31-1] so we + * must scale up the result by 2.0 to cover the full fractional + * range. */ dfuzz = ntp_random() * 2. / FRAC * sys_fuzz; DTOLFP(dfuzz, &lfpfuzz); @@ -240,30 +243,34 @@ get_systime( * Ensure result is strictly greater than prior result (ignoring * sys_residual's effect for now) once sys_fuzz has been * determined. + * + * [Bug 3450] Rounding errors and time slew can lead to a + * violation of the expected postcondition. This is bound to + * happen from time to time (depending on state of the random + * generator, the current slew and the closeness of system time + * stamps drawn) and does not warrant a syslog entry. Instead it + * makes much more sense to ensure the postcondition and hop + * along silently. */ if (!USING_SIGIO()) { - if (!L_ISZERO(&lfp_prev) && !lamport_violated) { - if (!L_ISGTU(&result, &lfp_prev) && - sys_fuzz > 0.) { - msyslog(LOG_ERR, "ts_prev %s ts_min %s", - tspectoa(ts_prev_log), - tspectoa(ts_min)); - msyslog(LOG_ERR, "ts %s", tspectoa(ts)); - msyslog(LOG_ERR, "sys_fuzz %ld nsec, prior fuzz %.9f", - sys_fuzz_nsec, dfuzz_prev); - msyslog(LOG_ERR, "this fuzz %.9f", - dfuzz); - lfpdelta = lfp_prev; - L_SUB(&lfpdelta, &result); - LFPTOD(&lfpdelta, ddelta); - msyslog(LOG_ERR, - "prev get_systime 0x%x.%08x is %.9f later than 0x%x.%08x", - lfp_prev.l_ui, lfp_prev.l_uf, - ddelta, result.l_ui, result.l_uf); + if ( !L_ISZERO(&lfp_prev) + && !lamport_violated + && (sys_fuzz > 0.0) + ) { + lfpdelta = result; + L_SUB(&lfpdelta, &lfp_prev); + L_SUBUF(&lfpdelta, 1); + if (lfpdelta.l_i < 0) + { + L_NEG(&lfpdelta); + DPRINTF(1, ("get_systime: postcond failed by %s secs, fixed\n", + lfptoa(&lfpdelta, 9))); + result = lfp_prev; + L_ADDUF(&result, 1); + sys_tsrounding++; } } lfp_prev = result; - dfuzz_prev = dfuzz; if (lamport_violated) lamport_violated = FALSE; } @@ -362,105 +369,16 @@ adj_systime( } #endif - /* - * step_systime - step the system clock. + * helper to keep utmp/wtmp up to date */ - -int -step_systime( - double step +static void +update_uwtmp( + struct timeval timetv, + struct timeval tvlast ) { - time_t pivot; /* for ntp era unfolding */ - struct timeval timetv, tvlast, tvdiff; - struct timespec timets; - struct calendar jd; - l_fp fp_ofs, fp_sys; /* offset and target system time in FP */ - - /* - * Get pivot time for NTP era unfolding. Since we don't step - * very often, we can afford to do the whole calculation from - * scratch. And we're not in the time-critical path yet. - */ -#if SIZEOF_TIME_T > 4 - /* - * This code makes sure the resulting time stamp for the new - * system time is in the 2^32 seconds starting at 1970-01-01, - * 00:00:00 UTC. - */ - pivot = 0x80000000; -#if USE_COMPILETIME_PIVOT - /* - * Add the compile time minus 10 years to get a possible target - * area of (compile time - 10 years) to (compile time + 126 - * years). This should be sufficient for a given binary of - * NTPD. - */ - if (ntpcal_get_build_date(&jd)) { - jd.year -= 10; - pivot += ntpcal_date_to_time(&jd); - } else { - msyslog(LOG_ERR, - "step-systime: assume 1970-01-01 as build date"); - } -#else - UNUSED_LOCAL(jd); -#endif /* USE_COMPILETIME_PIVOT */ -#else - UNUSED_LOCAL(jd); - /* This makes sure the resulting time stamp is on or after - * 1969-12-31/23:59:59 UTC and gives us additional two years, - * from the change of NTP era in 2036 to the UNIX rollover in - * 2038. (Minus one second, but that won't hurt.) We *really* - * need a longer 'time_t' after that! Or a different baseline, - * but that would cause other serious trouble, too. - */ - pivot = 0x7FFFFFFF; -#endif - - /* get the complete jump distance as l_fp */ - DTOLFP(sys_residual, &fp_sys); - DTOLFP(step, &fp_ofs); - L_ADD(&fp_ofs, &fp_sys); - - /* ---> time-critical path starts ---> */ - - /* get the current time as l_fp (without fuzz) and as struct timeval */ - get_ostime(&timets); - fp_sys = tspec_stamp_to_lfp(timets); - tvlast.tv_sec = timets.tv_sec; - tvlast.tv_usec = (timets.tv_nsec + 500) / 1000; - - /* get the target time as l_fp */ - L_ADD(&fp_sys, &fp_ofs); - - /* unfold the new system time */ - timetv = lfp_stamp_to_tval(fp_sys, &pivot); - - /* now set new system time */ - if (ntp_set_tod(&timetv, NULL) != 0) { - msyslog(LOG_ERR, "step-systime: %m"); - if (enable_panic_check && allow_panic) { - msyslog(LOG_ERR, "step_systime: allow_panic is TRUE!"); - } - return FALSE; - } - - /* <--- time-critical path ended with 'ntp_set_tod()' <--- */ - - sys_residual = 0; - lamport_violated = (step < 0); - if (step_callback) - (*step_callback)(); - -#ifdef NEED_HPUX_ADJTIME - /* - * CHECKME: is this correct when called by ntpdate????? - */ - _clear_adjtime(); -#endif - + struct timeval tvdiff; /* * FreeBSD, for example, has: * struct utmp { @@ -589,6 +507,83 @@ step_systime( #endif /* UPDATE_WTMPX */ } +} + +/* + * step_systime - step the system clock. + */ + +int +step_systime( + double step + ) +{ + time_t pivot; /* for ntp era unfolding */ + struct timeval timetv, tvlast; + struct timespec timets; + l_fp fp_ofs, fp_sys; /* offset and target system time in FP */ + + /* + * Get pivot time for NTP era unfolding. Since we don't step + * very often, we can afford to do the whole calculation from + * scratch. And we're not in the time-critical path yet. + */ +#if SIZEOF_TIME_T > 4 + pivot = basedate_get_eracenter(); +#else + /* This makes sure the resulting time stamp is on or after + * 1969-12-31/23:59:59 UTC and gives us additional two years, + * from the change of NTP era in 2036 to the UNIX rollover in + * 2038. (Minus one second, but that won't hurt.) We *really* + * need a longer 'time_t' after that! Or a different baseline, + * but that would cause other serious trouble, too. + */ + pivot = 0x7FFFFFFF; +#endif + + /* get the complete jump distance as l_fp */ + DTOLFP(sys_residual, &fp_sys); + DTOLFP(step, &fp_ofs); + L_ADD(&fp_ofs, &fp_sys); + + /* ---> time-critical path starts ---> */ + + /* get the current time as l_fp (without fuzz) and as struct timeval */ + get_ostime(&timets); + fp_sys = tspec_stamp_to_lfp(timets); + tvlast.tv_sec = timets.tv_sec; + tvlast.tv_usec = (timets.tv_nsec + 500) / 1000; + + /* get the target time as l_fp */ + L_ADD(&fp_sys, &fp_ofs); + + /* unfold the new system time */ + timetv = lfp_stamp_to_tval(fp_sys, &pivot); + + /* now set new system time */ + if (ntp_set_tod(&timetv, NULL) != 0) { + msyslog(LOG_ERR, "step-systime: %m"); + if (enable_panic_check && allow_panic) { + msyslog(LOG_ERR, "step_systime: allow_panic is TRUE!"); + } + return FALSE; + } + + /* <--- time-critical path ended with 'ntp_set_tod()' <--- */ + + sys_residual = 0; + lamport_violated = (step < 0); + if (step_callback) + (*step_callback)(); + +#ifdef NEED_HPUX_ADJTIME + /* + * CHECKME: is this correct when called by ntpdate????? + */ + _clear_adjtime(); +#endif + + update_uwtmp(timetv, tvlast); if (enable_panic_check && allow_panic) { msyslog(LOG_ERR, "step_systime: allow_panic is TRUE!"); INSIST(!allow_panic); @@ -596,4 +591,93 @@ step_systime( return TRUE; } +static const char * +tv_fmt_libbuf( + const struct timeval * ptv + ) +{ + char * retv; + vint64 secs; + ntpcal_split dds; + struct calendar jd; + + secs = time_to_vint64(&ptv->tv_sec); + dds = ntpcal_daysplit(&secs); + ntpcal_daysplit_to_date(&jd, &dds, DAY_UNIX_STARTS); + LIB_GETBUF(retv); + snprintf(retv, LIB_BUFLENGTH, + "%04hu-%02hu-%02hu/%02hu:%02hu:%02hu.%06u", + jd.year, (u_short)jd.month, (u_short)jd.monthday, + (u_short)jd.hour, (u_short)jd.minute, (u_short)jd.second, + (u_int)ptv->tv_usec); + return retv; +} + + +int /*BOOL*/ +clamp_systime(void) +{ +#if SIZEOF_TIME_T > 4 + + struct timeval timetv, tvlast; + struct timespec timets; + uint32_t tdiff; + + + timetv.tv_sec = basedate_get_erabase(); + + /* ---> time-critical path starts ---> */ + + /* get the current time as l_fp (without fuzz) and as struct timeval */ + get_ostime(&timets); + tvlast.tv_sec = timets.tv_sec; + tvlast.tv_usec = (timets.tv_nsec + 500) / 1000; + if (tvlast.tv_usec >= 1000000) { + tvlast.tv_usec -= 1000000; + tvlast.tv_sec += 1; + } + timetv.tv_usec = tvlast.tv_usec; + + tdiff = (uint32_t)(tvlast.tv_sec & UINT32_MAX) - + (uint32_t)(timetv.tv_sec & UINT32_MAX); + timetv.tv_sec += tdiff; + if (timetv.tv_sec != tvlast.tv_sec) { + /* now set new system time */ + if (ntp_set_tod(&timetv, NULL) != 0) { + msyslog(LOG_ERR, "clamp-systime: %m"); + return FALSE; + } + } else { + msyslog(LOG_INFO, + "clamp-systime: clock (%s) in allowed range", + tv_fmt_libbuf(&timetv)); + return FALSE; + } + + /* <--- time-critical path ended with 'ntp_set_tod()' <--- */ + + sys_residual = 0; + lamport_violated = (timetv.tv_sec < tvlast.tv_sec); + if (step_callback) + (*step_callback)(); + +# ifdef NEED_HPUX_ADJTIME + /* + * CHECKME: is this correct when called by ntpdate????? + */ + _clear_adjtime(); +# endif + + update_uwtmp(timetv, tvlast); + msyslog(LOG_WARNING, + "clamp-systime: clock stepped from %s to %s!", + tv_fmt_libbuf(&tvlast), tv_fmt_libbuf(&timetv)); + return TRUE; + +#else + + return 0; +#endif +} + #endif /* !SIM */ |
