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src/core/ngx_times.c - nginx source code

Global variables defined

Functions defined

Macros defined

Source code


  2. /*
  3. * Copyright (C) Igor Sysoev
  4. * Copyright (C) Nginx, Inc.
  5. */


  8. #include <ngx_config.h>
  9. #include <ngx_core.h>


  12. static ngx_msec_t ngx_monotonic_time(time_t sec, ngx_uint_t msec);


  15. /*
  16. * The time may be updated by signal handler or by several threads.
  17. * The time update operations are rare and require to hold the ngx_time_lock.
  18. * The time read operations are frequent, so they are lock-free and get time
  19. * values and strings from the current slot.  Thus thread may get the corrupted
  20. * values only if it is preempted while copying and then it is not scheduled
  21. * to run more than NGX_TIME_SLOTS seconds.
  22. */

  24. ‌#define NGX_TIME_SLOTS   64

  26. ‌static ngx_uint_t        slot;
  27. ‌static ngx_atomic_t      ngx_time_lock;

  29. ‌volatile ngx_msec_t      ngx_current_msec;
  30. ‌volatile ngx_time_t     *ngx_cached_time;
  31. ‌volatile ngx_str_t       ngx_cached_err_log_time;
  32. ‌volatile ngx_str_t       ngx_cached_http_time;
  33. ‌volatile ngx_str_t       ngx_cached_http_log_time;
  34. ‌volatile ngx_str_t       ngx_cached_http_log_iso8601;
  35. ‌volatile ngx_str_t       ngx_cached_syslog_time;

  37. #if !(NGX_WIN32)

  39. /*
  40. * localtime() and localtime_r() are not Async-Signal-Safe functions, therefore,
  41. * they must not be called by a signal handler, so we use the cached
  42. * GMT offset value. Fortunately the value is changed only two times a year.
  43. */

  45. ‌static ngx_int_t         cached_gmtoff;
  46. #endif

  48. ‌static ngx_time_t        cached_time[NGX_TIME_SLOTS];
  49. ‌static u_char            cached_err_log_time[NGX_TIME_SLOTS]
  50.                                     [sizeof("1970/09/28 12:00:00")];
  51. ‌static u_char            cached_http_time[NGX_TIME_SLOTS]
  52.                                     [sizeof("Mon, 28 Sep 1970 06:00:00 GMT")];
  53. ‌static u_char            cached_http_log_time[NGX_TIME_SLOTS]
  54.                                     [sizeof("28/Sep/1970:12:00:00 +0600")];
  55. ‌static u_char            cached_http_log_iso8601[NGX_TIME_SLOTS]
  56.                                     [sizeof("1970-09-28T12:00:00+06:00")];
  57. ‌static u_char            cached_syslog_time[NGX_TIME_SLOTS]
  58.                                     [sizeof("Sep 28 12:00:00")];


  61. ‌static char  *week[] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };
  62. ‌static char  *months[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
  63.                            "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };

  65. void
  66. ‌ngx_time_init(void)
  67. {
  68.     ngx_cached_err_log_time.len = sizeof("1970/09/28 12:00:00") - 1;
  69.     ngx_cached_http_time.len = sizeof("Mon, 28 Sep 1970 06:00:00 GMT") - 1;
  70.     ngx_cached_http_log_time.len = sizeof("28/Sep/1970:12:00:00 +0600") - 1;
  71.     ngx_cached_http_log_iso8601.len = sizeof("1970-09-28T12:00:00+06:00") - 1;
  72.     ngx_cached_syslog_time.len = sizeof("Sep 28 12:00:00") - 1;

  74.     ngx_cached_time = &cached_time[0];

  76.     ngx_time_update();
  77. }


  80. void
  81. ‌ngx_time_update(void)
  82. {
  83.     u_char          *p0, *p1, *p2, *p3, *p4;
  84.     ngx_tm_t         tm, gmt;
  85.     time_t           sec;
  86.     ngx_uint_t       msec;
  87.     ngx_time_t      *tp;
  88.     struct timeval   tv;

  90.     if (!ngx_trylock(&ngx_time_lock)) {
  91.         return;
  92.     }

  94.     ngx_gettimeofday(&tv);

  96.     sec = tv.tv_sec;
  97.     msec = tv.tv_usec / 1000;

  99.     ngx_current_msec = ngx_monotonic_time(sec, msec);

  101.     tp = &cached_time[slot];

  103.     if (tp->sec == sec) {
  104.         tp->msec = msec;
  105.         ngx_unlock(&ngx_time_lock);
  106.         return;
  107.     }

  109.     if (slot == NGX_TIME_SLOTS - 1) {
  110.         slot = 0;
  111.     } else {
  112.         slot++;
  113.     }

  115.     tp = &cached_time[slot];

  117.     tp->sec = sec;
  118.     tp->msec = msec;

  120.     ngx_gmtime(sec, &gmt);


  123.     p0 = &cached_http_time[slot][0];

  125.     (void) ngx_sprintf(p0, "%s, %02d %s %4d %02d:%02d:%02d GMT",
  126.                        week[gmt.ngx_tm_wday], gmt.ngx_tm_mday,
  127.                        months[gmt.ngx_tm_mon - 1], gmt.ngx_tm_year,
  128.                        gmt.ngx_tm_hour, gmt.ngx_tm_min, gmt.ngx_tm_sec);

  130. #if (NGX_HAVE_GETTIMEZONE)

  132.     tp->gmtoff = ngx_gettimezone();
  133.     ngx_gmtime(sec + tp->gmtoff * 60, &tm);

  135. #elif (NGX_HAVE_GMTOFF)

  137.     ngx_localtime(sec, &tm);
  138.     cached_gmtoff = (ngx_int_t) (tm.ngx_tm_gmtoff / 60);
  139.     tp->gmtoff = cached_gmtoff;

  141. #else

  143.     ngx_localtime(sec, &tm);
  144.     cached_gmtoff = ngx_timezone(tm.ngx_tm_isdst);
  145.     tp->gmtoff = cached_gmtoff;

  147. #endif


  150.     p1 = &cached_err_log_time[slot][0];

  152.     (void) ngx_sprintf(p1, "%4d/%02d/%02d %02d:%02d:%02d",
  153.                        tm.ngx_tm_year, tm.ngx_tm_mon,
  154.                        tm.ngx_tm_mday, tm.ngx_tm_hour,
  155.                        tm.ngx_tm_min, tm.ngx_tm_sec);


  158.     p2 = &cached_http_log_time[slot][0];

  160.     (void) ngx_sprintf(p2, "%02d/%s/%d:%02d:%02d:%02d %c%02i%02i",
  161.                        tm.ngx_tm_mday, months[tm.ngx_tm_mon - 1],
  162.                        tm.ngx_tm_year, tm.ngx_tm_hour,
  163.                        tm.ngx_tm_min, tm.ngx_tm_sec,
  164.                        tp->gmtoff < 0 ? '-' : '+',
  165.                        ngx_abs(tp->gmtoff / 60), ngx_abs(tp->gmtoff % 60));

  167.     p3 = &cached_http_log_iso8601[slot][0];

  169.     (void) ngx_sprintf(p3, "%4d-%02d-%02dT%02d:%02d:%02d%c%02i:%02i",
  170.                        tm.ngx_tm_year, tm.ngx_tm_mon,
  171.                        tm.ngx_tm_mday, tm.ngx_tm_hour,
  172.                        tm.ngx_tm_min, tm.ngx_tm_sec,
  173.                        tp->gmtoff < 0 ? '-' : '+',
  174.                        ngx_abs(tp->gmtoff / 60), ngx_abs(tp->gmtoff % 60));

  176.     p4 = &cached_syslog_time[slot][0];

  178.     (void) ngx_sprintf(p4, "%s %2d %02d:%02d:%02d",
  179.                        months[tm.ngx_tm_mon - 1], tm.ngx_tm_mday,
  180.                        tm.ngx_tm_hour, tm.ngx_tm_min, tm.ngx_tm_sec);

  182.     ngx_memory_barrier();

  184.     ngx_cached_time = tp;
  185.     ngx_cached_http_time.data = p0;
  186.     ngx_cached_err_log_time.data = p1;
  187.     ngx_cached_http_log_time.data = p2;
  188.     ngx_cached_http_log_iso8601.data = p3;
  189.     ngx_cached_syslog_time.data = p4;

  191.     ngx_unlock(&ngx_time_lock);
  192. }


  195. static ngx_msec_t
  196. ‌ngx_monotonic_time(time_t sec, ngx_uint_t msec)
  197. {
  198. #if (NGX_HAVE_CLOCK_MONOTONIC)
  199.     struct timespec  ts;

  201. #if defined(CLOCK_MONOTONIC_FAST)
  202.     clock_gettime(CLOCK_MONOTONIC_FAST, &ts);
  203. #else
  204.     clock_gettime(CLOCK_MONOTONIC, &ts);
  205. #endif

  207.     sec = ts.tv_sec;
  208.     msec = ts.tv_nsec / 1000000;

  210. #endif

  212.     return (ngx_msec_t) sec * 1000 + msec;
  213. }


  216. #if !(NGX_WIN32)

  218. void
  219. ‌ngx_time_sigsafe_update(void)
  220. {
  221.     u_char          *p, *p2;
  222.     ngx_tm_t         tm;
  223.     time_t           sec;
  224.     ngx_time_t      *tp;
  225.     struct timeval   tv;

  227.     if (!ngx_trylock(&ngx_time_lock)) {
  228.         return;
  229.     }

  231.     ngx_gettimeofday(&tv);

  233.     sec = tv.tv_sec;

  235.     tp = &cached_time[slot];

  237.     if (tp->sec == sec) {
  238.         ngx_unlock(&ngx_time_lock);
  239.         return;
  240.     }

  242.     if (slot == NGX_TIME_SLOTS - 1) {
  243.         slot = 0;
  244.     } else {
  245.         slot++;
  246.     }

  248.     tp = &cached_time[slot];

  250.     tp->sec = 0;

  252.     ngx_gmtime(sec + cached_gmtoff * 60, &tm);

  254.     p = &cached_err_log_time[slot][0];

  256.     (void) ngx_sprintf(p, "%4d/%02d/%02d %02d:%02d:%02d",
  257.                        tm.ngx_tm_year, tm.ngx_tm_mon,
  258.                        tm.ngx_tm_mday, tm.ngx_tm_hour,
  259.                        tm.ngx_tm_min, tm.ngx_tm_sec);

  261.     p2 = &cached_syslog_time[slot][0];

  263.     (void) ngx_sprintf(p2, "%s %2d %02d:%02d:%02d",
  264.                        months[tm.ngx_tm_mon - 1], tm.ngx_tm_mday,
  265.                        tm.ngx_tm_hour, tm.ngx_tm_min, tm.ngx_tm_sec);

  267.     ngx_memory_barrier();

  269.     ngx_cached_err_log_time.data = p;
  270.     ngx_cached_syslog_time.data = p2;

  272.     ngx_unlock(&ngx_time_lock);
  273. }

  275. #endif


  278. u_char *
  279. ‌ngx_http_time(u_char *buf, time_t t)
  280. {
  281.     ngx_tm_t  tm;

  283.     ngx_gmtime(t, &tm);

  285.     return ngx_sprintf(buf, "%s, %02d %s %4d %02d:%02d:%02d GMT",
  286.                        week[tm.ngx_tm_wday],
  287.                        tm.ngx_tm_mday,
  288.                        months[tm.ngx_tm_mon - 1],
  289.                        tm.ngx_tm_year,
  290.                        tm.ngx_tm_hour,
  291.                        tm.ngx_tm_min,
  292.                        tm.ngx_tm_sec);
  293. }


  296. u_char *
  297. ‌ngx_http_cookie_time(u_char *buf, time_t t)
  298. {
  299.     ngx_tm_t  tm;

  301.     ngx_gmtime(t, &tm);

  303.     /*
  304.      * Netscape 3.x does not understand 4-digit years at all and
  305.      * 2-digit years more than "37"
  306.      */

  308.     return ngx_sprintf(buf,
  309.                        (tm.ngx_tm_year > 2037) ?
  310.                                          "%s, %02d-%s-%d %02d:%02d:%02d GMT":
  311.                                          "%s, %02d-%s-%02d %02d:%02d:%02d GMT",
  312.                        week[tm.ngx_tm_wday],
  313.                        tm.ngx_tm_mday,
  314.                        months[tm.ngx_tm_mon - 1],
  315.                        (tm.ngx_tm_year > 2037) ? tm.ngx_tm_year:
  316.                                                  tm.ngx_tm_year % 100,
  317.                        tm.ngx_tm_hour,
  318.                        tm.ngx_tm_min,
  319.                        tm.ngx_tm_sec);
  320. }


  323. void
  324. ‌ngx_gmtime(time_t t, ngx_tm_t *tp)
  325. {
  326.     ngx_int_t   yday;
  327.     ngx_uint_t  sec, min, hour, mday, mon, year, wday, days, leap;

  329.     /* the calculation is valid for positive time_t only */

  331.     if (t < 0) {
  332.         t = 0;
  333.     }

  335.     days = t / 86400;
  336.     sec = t % 86400;

  338.     /*
  339.      * no more than 4 year digits supported,
  340.      * truncate to December 31, 9999, 23:59:59
  341.      */

  343.     if (days > 2932896) {
  344.         days = 2932896;
  345.         sec = 86399;
  346.     }

  348.     /* January 1, 1970 was Thursday */

  350.     wday = (4 + days) % 7;

  352.     hour = sec / 3600;
  353.     sec %= 3600;
  354.     min = sec / 60;
  355.     sec %= 60;

  357.     /*
  358.      * the algorithm based on Gauss' formula,
  359.      * see src/core/ngx_parse_time.c
  360.      */

  362.     /* days since March 1, 1 BC */
  363.     days = days - (31 + 28) + 719527;

  365.     /*
  366.      * The "days" should be adjusted to 1 only, however, some March 1st's go
  367.      * to previous year, so we adjust them to 2.  This causes also shift of the
  368.      * last February days to next year, but we catch the case when "yday"
  369.      * becomes negative.
  370.      */

  372.     year = (days + 2) * 400 / (365 * 400 + 100 - 4 + 1);

  374.     yday = days - (365 * year + year / 4 - year / 100 + year / 400);

  376.     if (yday < 0) {
  377.         leap = (year % 4 == 0) && (year % 100 || (year % 400 == 0));
  378.         yday = 365 + leap + yday;
  379.         year--;
  380.     }

  382.     /*
  383.      * The empirical formula that maps "yday" to month.
  384.      * There are at least 10 variants, some of them are:
  385.      *     mon = (yday + 31) * 15 / 459
  386.      *     mon = (yday + 31) * 17 / 520
  387.      *     mon = (yday + 31) * 20 / 612
  388.      */

  390.     mon = (yday + 31) * 10 / 306;

  392.     /* the Gauss' formula that evaluates days before the month */

  394.     mday = yday - (367 * mon / 12 - 30) + 1;

  396.     if (yday >= 306) {

  398.         year++;
  399.         mon -= 10;

  401.         /*
  402.          * there is no "yday" in Win32 SYSTEMTIME
  403.          *
  404.          * yday -= 306;
  405.          */

  407.     } else {

  409.         mon += 2;

  411.         /*
  412.          * there is no "yday" in Win32 SYSTEMTIME
  413.          *
  414.          * yday += 31 + 28 + leap;
  415.          */
  416.     }

  418.     tp->ngx_tm_sec = (ngx_tm_sec_t) sec;
  419.     tp->ngx_tm_min = (ngx_tm_min_t) min;
  420.     tp->ngx_tm_hour = (ngx_tm_hour_t) hour;
  421.     tp->ngx_tm_mday = (ngx_tm_mday_t) mday;
  422.     tp->ngx_tm_mon = (ngx_tm_mon_t) mon;
  423.     tp->ngx_tm_year = (ngx_tm_year_t) year;
  424.     tp->ngx_tm_wday = (ngx_tm_wday_t) wday;
  425. }


  428. time_t
  429. ‌ngx_next_time(time_t when)
  430. {
  431.     time_t     now, next;
  432.     struct tm  tm;

  434.     now = ngx_time();

  436.     ngx_libc_localtime(now, &tm);

  438.     tm.tm_hour = (int) (when / 3600);
  439.     when %= 3600;
  440.     tm.tm_min = (int) (when / 60);
  441.     tm.tm_sec = (int) (when % 60);

  443.     next = mktime(&tm);

  445.     if (next == -1) {
  446.         return -1;
  447.     }

  449.     if (next - now > 0) {
  450.         return next;
  451.     }

  453.     tm.tm_mday++;

  455.     /* mktime() should normalize a date (Jan 32, etc) */

  457.     next = mktime(&tm);

  459.     if (next != -1) {
  460.         return next;
  461.     }

  463.     return -1;
  464. }

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