release/src/router/nginx/src/core/ngx_times.c

   1
   2 /*
   3  * Copyright (C) Igor Sysoev
   4  * Copyright (C) Nginx, Inc.
   5  */
   6
   7
   8 #include <ngx_config.h>
   9 #include <ngx_core.h>
  10
  11
  12 /*
  13  * The time may be updated by signal handler or by several threads.
  14  * The time update operations are rare and require to hold the ngx_time_lock.
  15  * The time read operations are frequent, so they are lock-free and get time
  16  * values and strings from the current slot.  Thus thread may get the corrupted
  17  * values only if it is preempted while copying and then it is not scheduled
  18  * to run more than NGX_TIME_SLOTS seconds.
  19  */
  20
  21 #define NGX_TIME_SLOTS   64
  22
  23 static ngx_uint_t        slot;
  24 static ngx_atomic_t      ngx_time_lock;
  25
  26 volatile ngx_msec_t      ngx_current_msec;
  27 volatile ngx_time_t     *ngx_cached_time;
  28 volatile ngx_str_t       ngx_cached_err_log_time;
  29 volatile ngx_str_t       ngx_cached_http_time;
  30 volatile ngx_str_t       ngx_cached_http_log_time;
  31 volatile ngx_str_t       ngx_cached_http_log_iso8601;
  32
  33 #if !(NGX_WIN32)
  34
  35 /*
  36  * localtime() and localtime_r() are not Async-Signal-Safe functions, therefore,
  37  * they must not be called by a signal handler, so we use the cached
  38  * GMT offset value. Fortunately the value is changed only two times a year.
  39  */
  40
  41 static ngx_int_t         cached_gmtoff;
  42 #endif
  43
  44 static ngx_time_t        cached_time[NGX_TIME_SLOTS];
  45 static u_char            cached_err_log_time[NGX_TIME_SLOTS]
  46                                     [sizeof("1970/09/28 12:00:00")];
  47 static u_char            cached_http_time[NGX_TIME_SLOTS]
  48                                     [sizeof("Mon, 28 Sep 1970 06:00:00 GMT")];
  49 static u_char            cached_http_log_time[NGX_TIME_SLOTS]
  50                                     [sizeof("28/Sep/1970:12:00:00 +0600")];
  51 static u_char            cached_http_log_iso8601[NGX_TIME_SLOTS]
  52                                     [sizeof("1970-09-28T12:00:00+06:00")];
  53
  54
  55 static char  *week[] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" };
  56 static char  *months[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
  57                            "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
  58
  59 void
  60 ngx_time_init(void)
  61 {
  62     ngx_cached_err_log_time.len = sizeof("1970/09/28 12:00:00") - 1;
  63     ngx_cached_http_time.len = sizeof("Mon, 28 Sep 1970 06:00:00 GMT") - 1;
  64     ngx_cached_http_log_time.len = sizeof("28/Sep/1970:12:00:00 +0600") - 1;
  65     ngx_cached_http_log_iso8601.len = sizeof("1970-09-28T12:00:00+06:00") - 1;
  66
  67     ngx_cached_time = &cached_time[0];
  68
  69     ngx_time_update();
  70 }
  71
  72
  73 void
  74 ngx_time_update(void)
  75 {
  76     u_char          *p0, *p1, *p2, *p3;
  77     ngx_tm_t         tm, gmt;
  78     time_t           sec;
  79     ngx_uint_t       msec;
  80     ngx_time_t      *tp;
  81     struct timeval   tv;
  82
  83     if (!ngx_trylock(&ngx_time_lock)) {
  84         return;
  85     }
  86
  87     ngx_gettimeofday(&tv);
  88
  89     sec = tv.tv_sec;
  90     msec = tv.tv_usec / 1000;
  91
  92     ngx_current_msec = (ngx_msec_t) sec * 1000 + msec;
  93
  94     tp = &cached_time[slot];
  95
  96     if (tp->sec == sec) {
  97         tp->msec = msec;
  98         ngx_unlock(&ngx_time_lock);
  99         return;
 100     }
 101
 102     if (slot == NGX_TIME_SLOTS - 1) {
 103         slot = 0;
 104     } else {
 105         slot++;
 106     }
 107
 108     tp = &cached_time[slot];
 109
 110     tp->sec = sec;
 111     tp->msec = msec;
 112
 113     ngx_gmtime(sec, &gmt);
 114
 115
 116     p0 = &cached_http_time[slot][0];
 117
 118     (void) ngx_sprintf(p0, "%s, %02d %s %4d %02d:%02d:%02d GMT",
 119                        week[gmt.ngx_tm_wday], gmt.ngx_tm_mday,
 120                        months[gmt.ngx_tm_mon - 1], gmt.ngx_tm_year,
 121                        gmt.ngx_tm_hour, gmt.ngx_tm_min, gmt.ngx_tm_sec);
 122
 123 #if (NGX_HAVE_GETTIMEZONE)
 124
 125     tp->gmtoff = ngx_gettimezone();
 126     ngx_gmtime(sec + tp->gmtoff * 60, &tm);
 127
 128 #elif (NGX_HAVE_GMTOFF)
 129
 130     ngx_localtime(sec, &tm);
 131     cached_gmtoff = (ngx_int_t) (tm.ngx_tm_gmtoff / 60);
 132     tp->gmtoff = cached_gmtoff;
 133
 134 #else
 135
 136     ngx_localtime(sec, &tm);
 137     cached_gmtoff = ngx_timezone(tm.ngx_tm_isdst);
 138     tp->gmtoff = cached_gmtoff;
 139
 140 #endif
 141
 142
 143     p1 = &cached_err_log_time[slot][0];
 144
 145     (void) ngx_sprintf(p1, "%4d/%02d/%02d %02d:%02d:%02d",
 146                        tm.ngx_tm_year, tm.ngx_tm_mon,
 147                        tm.ngx_tm_mday, tm.ngx_tm_hour,
 148                        tm.ngx_tm_min, tm.ngx_tm_sec);
 149
 150
 151     p2 = &cached_http_log_time[slot][0];
 152
 153     (void) ngx_sprintf(p2, "%02d/%s/%d:%02d:%02d:%02d %c%02d%02d",
 154                        tm.ngx_tm_mday, months[tm.ngx_tm_mon - 1],
 155                        tm.ngx_tm_year, tm.ngx_tm_hour,
 156                        tm.ngx_tm_min, tm.ngx_tm_sec,
 157                        tp->gmtoff < 0 ? '-' : '+',
 158                        ngx_abs(tp->gmtoff / 60), ngx_abs(tp->gmtoff % 60));
 159
 160     p3 = &cached_http_log_iso8601[slot][0];
 161
 162     (void) ngx_sprintf(p3, "%4d-%02d-%02dT%02d:%02d:%02d%c%02d:%02d",
 163                        tm.ngx_tm_year, tm.ngx_tm_mon,
 164                        tm.ngx_tm_mday, tm.ngx_tm_hour,
 165                        tm.ngx_tm_min, tm.ngx_tm_sec,
 166                        tp->gmtoff < 0 ? '-' : '+',
 167                        ngx_abs(tp->gmtoff / 60), ngx_abs(tp->gmtoff % 60));
 168
 169
 170     ngx_memory_barrier();
 171
 172     ngx_cached_time = tp;
 173     ngx_cached_http_time.data = p0;
 174     ngx_cached_err_log_time.data = p1;
 175     ngx_cached_http_log_time.data = p2;
 176     ngx_cached_http_log_iso8601.data = p3;
 177
 178     ngx_unlock(&ngx_time_lock);
 179 }
 180
 181
 182 #if !(NGX_WIN32)
 183
 184 void
 185 ngx_time_sigsafe_update(void)
 186 {
 187     u_char          *p;
 188     ngx_tm_t         tm;
 189     time_t           sec;
 190     ngx_time_t      *tp;
 191     struct timeval   tv;
 192
 193     if (!ngx_trylock(&ngx_time_lock)) {
 194         return;
 195     }
 196
 197     ngx_gettimeofday(&tv);
 198
 199     sec = tv.tv_sec;
 200
 201     tp = &cached_time[slot];
 202
 203     if (tp->sec == sec) {
 204         ngx_unlock(&ngx_time_lock);
 205         return;
 206     }
 207
 208     if (slot == NGX_TIME_SLOTS - 1) {
 209         slot = 0;
 210     } else {
 211         slot++;
 212     }
 213
 214     tp = &cached_time[slot];
 215
 216     tp->sec = 0;
 217
 218     ngx_gmtime(sec + cached_gmtoff * 60, &tm);
 219
 220     p = &cached_err_log_time[slot][0];
 221
 222     (void) ngx_sprintf(p, "%4d/%02d/%02d %02d:%02d:%02d",
 223                        tm.ngx_tm_year, tm.ngx_tm_mon,
 224                        tm.ngx_tm_mday, tm.ngx_tm_hour,
 225                        tm.ngx_tm_min, tm.ngx_tm_sec);
 226
 227     ngx_memory_barrier();
 228
 229     ngx_cached_err_log_time.data = p;
 230
 231     ngx_unlock(&ngx_time_lock);
 232 }
 233
 234 #endif
 235
 236
 237 u_char *
 238 ngx_http_time(u_char *buf, time_t t)
 239 {
 240     ngx_tm_t  tm;
 241
 242     ngx_gmtime(t, &tm);
 243
 244     return ngx_sprintf(buf, "%s, %02d %s %4d %02d:%02d:%02d GMT",
 245                        week[tm.ngx_tm_wday],
 246                        tm.ngx_tm_mday,
 247                        months[tm.ngx_tm_mon - 1],
 248                        tm.ngx_tm_year,
 249                        tm.ngx_tm_hour,
 250                        tm.ngx_tm_min,
 251                        tm.ngx_tm_sec);
 252 }
 253
 254
 255 u_char *
 256 ngx_http_cookie_time(u_char *buf, time_t t)
 257 {
 258     ngx_tm_t  tm;
 259
 260     ngx_gmtime(t, &tm);
 261
 262     /*
 263      * Netscape 3.x does not understand 4-digit years at all and
 264      * 2-digit years more than "37"
 265      */
 266
 267     return ngx_sprintf(buf,
 268                        (tm.ngx_tm_year > 2037) ?
 269                                          "%s, %02d-%s-%d %02d:%02d:%02d GMT":
 270                                          "%s, %02d-%s-%02d %02d:%02d:%02d GMT",
 271                        week[tm.ngx_tm_wday],
 272                        tm.ngx_tm_mday,
 273                        months[tm.ngx_tm_mon - 1],
 274                        (tm.ngx_tm_year > 2037) ? tm.ngx_tm_year:
 275                                                  tm.ngx_tm_year % 100,
 276                        tm.ngx_tm_hour,
 277                        tm.ngx_tm_min,
 278                        tm.ngx_tm_sec);
 279 }
 280
 281
 282 void
 283 ngx_gmtime(time_t t, ngx_tm_t *tp)
 284 {
 285     ngx_int_t   yday;
 286     ngx_uint_t  n, sec, min, hour, mday, mon, year, wday, days, leap;
 287
 288     /* the calculation is valid for positive time_t only */
 289
 290     n = (ngx_uint_t) t;
 291
 292     days = n / 86400;
 293
 294     /* January 1, 1970 was Thursday */
 295
 296     wday = (4 + days) % 7;
 297
 298     n %= 86400;
 299     hour = n / 3600;
 300     n %= 3600;
 301     min = n / 60;
 302     sec = n % 60;
 303
 304     /*
 305      * the algorithm based on Gauss' formula,
 306      * see src/http/ngx_http_parse_time.c
 307      */
 308
 309     /* days since March 1, 1 BC */
 310     days = days - (31 + 28) + 719527;
 311
 312     /*
 313      * The "days" should be adjusted to 1 only, however, some March 1st's go
 314      * to previous year, so we adjust them to 2.  This causes also shift of the
 315      * last February days to next year, but we catch the case when "yday"
 316      * becomes negative.
 317      */
 318
 319     year = (days + 2) * 400 / (365 * 400 + 100 - 4 + 1);
 320
 321     yday = days - (365 * year + year / 4 - year / 100 + year / 400);
 322
 323     if (yday < 0) {
 324         leap = (year % 4 == 0) && (year % 100 || (year % 400 == 0));
 325         yday = 365 + leap + yday;
 326         year--;
 327     }
 328
 329     /*
 330      * The empirical formula that maps "yday" to month.
 331      * There are at least 10 variants, some of them are:
 332      *     mon = (yday + 31) * 15 / 459
 333      *     mon = (yday + 31) * 17 / 520
 334      *     mon = (yday + 31) * 20 / 612
 335      */
 336
 337     mon = (yday + 31) * 10 / 306;
 338
 339     /* the Gauss' formula that evaluates days before the month */
 340
 341     mday = yday - (367 * mon / 12 - 30) + 1;
 342
 343     if (yday >= 306) {
 344
 345         year++;
 346         mon -= 10;
 347
 348         /*
 349          * there is no "yday" in Win32 SYSTEMTIME
 350          *
 351          * yday -= 306;
 352          */
 353
 354     } else {
 355
 356         mon += 2;
 357
 358         /*
 359          * there is no "yday" in Win32 SYSTEMTIME
 360          *
 361          * yday += 31 + 28 + leap;
 362          */
 363     }
 364
 365     tp->ngx_tm_sec = (ngx_tm_sec_t) sec;
 366     tp->ngx_tm_min = (ngx_tm_min_t) min;
 367     tp->ngx_tm_hour = (ngx_tm_hour_t) hour;
 368     tp->ngx_tm_mday = (ngx_tm_mday_t) mday;
 369     tp->ngx_tm_mon = (ngx_tm_mon_t) mon;
 370     tp->ngx_tm_year = (ngx_tm_year_t) year;
 371     tp->ngx_tm_wday = (ngx_tm_wday_t) wday;
 372 }
 373
 374
 375 time_t
 376 ngx_next_time(time_t when)
 377 {
 378     time_t     now, next;
 379     struct tm  tm;
 380
 381     now = ngx_time();
 382
 383     ngx_libc_localtime(now, &tm);
 384
 385     tm.tm_hour = (int) (when / 3600);
 386     when %= 3600;
 387     tm.tm_min = (int) (when / 60);
 388     tm.tm_sec = (int) (when % 60);
 389
 390     next = mktime(&tm);
 391
 392     if (next == -1) {
 393         return -1;
 394     }
 395
 396     if (next - now > 0) {
 397         return next;
 398     }
 399
 400     tm.tm_mday++;
 401
 402     /* mktime() should normalize a date (Jan 32, etc) */
 403
 404     next = mktime(&tm);
 405
 406     if (next != -1) {
 407         return next;
 408     }
 409
 410     return -1;
 411 }