http_date.c

   1 /*
   2  * Copyright (C) 2012-2020 all contributors <cmogstored-public@yhbt.net>
   3  * License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
   4  */
   5 #include "cmogstored.h"
   6
   7 /* avoiding strftime() since it's locale-aware */
   8
   9 #define DATELEN (MOG_HTTPDATE_CAPA - 1)
  10 static const char week[] = "Sun\0Mon\0Tue\0Wed\0Thu\0Fri\0Sat";
  11 static const char months[] = "Jan\0Feb\0Mar\0Apr\0May\0Jun\0"
  12                              "Jul\0Aug\0Sep\0Oct\0Nov\0Dec";
  13
  14 __attribute__((constructor)) static void http_date_init(void)
  15 {
  16         time_t now = time(NULL);
  17         struct tm tm;
  18
  19         /*
  20          * call gmtime_r once in the main loop to load, TZ info.
  21          * Initial run uses a lot of stack on *BSDs
  22          */
  23         gmtime_r(&now, &tm);
  24 }
  25
  26 char *mog_http_date(char *dst, size_t len, const time_t *timep)
  27 {
  28         int rc;
  29         struct tm tm;
  30
  31         assert(len >= MOG_HTTPDATE_CAPA && "date length incorrect");
  32         gmtime_r(timep, &tm);
  33
  34         /* snprintf eats stack :( */
  35         rc = snprintf(dst, len, "%s, %02d %s %4d %02d:%02d:%02d GMT",
  36                          week + (tm.tm_wday * 4),
  37                          tm.tm_mday,
  38                          months + (tm.tm_mon * 4),
  39                          tm.tm_year + 1900,
  40                          tm.tm_hour,
  41                          tm.tm_min,
  42                          tm.tm_sec);
  43         assert(rc == DATELEN && "bad sprintf return value");
  44
  45         return dst + rc;
  46 }
  47
  48 struct mog_now *mog_now(void)
  49 {
  50         static __thread struct mog_now now;
  51         time_t tnow = time(NULL); /* not a syscall on modern 64-bit systems */
  52
  53         if (now.ntime == tnow)
  54                 return &now;
  55
  56         now.ntime = tnow;
  57         mog_http_date(now.httpdate, sizeof(now.httpdate), &tnow);
  58
  59         return &now;
  60 }