[core] http_date_timegm() (portable timegm())

move from mod_openssl.c

src/http_date.c

@@ -276,26 +276,24 @@ http_date_time_to_str (char * const s, const size_t sz, const time_t t)
 }
 
 
-#ifdef HAVE_TIMEGM
-#define http_date_timegm(tm) timegm(tm)
-#else
-#ifdef _WIN32
-#define http_date_timegm(tm) _mkgmtime(tm)
-#else
-/* If OS missing timegm(), then for best portability it is recommended to set
- *   $ export LC_TIME=C TZ=UTC0
- * or else time comparisons may be off by timezone offset (!!)
- *
- * tm->tm_isdst = 0 for mktime() to indicate daylight saving time not in effect
- * which is fine since HTTP date strings should be GMT dates
- *
- * If not TZ=UTC0, and timegm() is not present, then can we expect gmtime() to
- * be available so that we can mktime(gmtime_r(lmtime, &gtm)) ?  That would be
- * an expensive way to obtain TZ offset.  XXX: maybe calculate TZ offset once
- * at startup?  Are there any (modern) systems missing timegm() or _mkgmtime()?
- */
-#define http_date_timegm(tm) ((tm)->tm_isdst = 0, mktime(tm))
-#endif
+#if !defined(HAVE_TIMEGM) && !defined(_WIN32)
+time_t
+http_date_timegm (const struct tm * const tm)
+{
+    int y = tm->tm_year + 1900;
+    int m = tm->tm_mon + 1;
+    int d = tm->tm_mday;
+
+    /* days_from_civil() http://howardhinnant.github.io/date_algorithms.html */
+    y -= m <= 2;
+    int era = y / 400;
+    int yoe = y - era * 400;                                   // [0, 399]
+    int doy = (153 * (m + (m > 2 ? -3 : 9)) + 2) / 5 + d - 1;  // [0, 365]
+    int doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;           // [0, 146096]
+    int days_since_1970 = era * 146097 + doe - 719468;
+
+    return 60*(60*(24L*days_since_1970+tm->tm_hour)+tm->tm_min)+tm->tm_sec;
+}
 #endif
 
 

src/http_date.h

@@ -8,6 +8,8 @@
 #define INCLUDED_HTTP_DATE_H
 #include "first.h"
 
+#include "sys-time.h"
+
 
 #ifdef __cplusplus
 extern "C" {
@@ -20,6 +22,14 @@ uint32_t http_date_time_to_str (char *s, size_t sz, time_t t);
 
 int http_date_if_modified_since (const char *ifmod, uint32_t ifmodlen, time_t lmtime);
 
+#ifdef HAVE_TIMEGM
+#define http_date_timegm(tm) timegm(tm)
+#elif defined(_WIN32)
+#define http_date_timegm(tm) _mkgmtime(tm)
+#else
+time_t http_date_timegm (const struct tm *tm);
+#endif
+
 
 #ifdef __cplusplus
 }

src/mod_openssl.c

@@ -84,6 +84,7 @@
 
 #include "base.h"
 #include "fdevent.h"
+#include "http_date.h"
 #include "http_header.h"
 #include "http_kv.h"
 #include "log.h"
@@ -1448,28 +1449,10 @@ mod_openssl_asn1_time_to_posix (ASN1_TIME *asn1time)
         && x.tm_hour == 23 && x.tm_min == 59 && x.tm_sec == 59 && s[0] == 'Z')
         return (time_t)-1; // 99991231235959Z RFC 5280
 
-   #if 0
-    #if defined(_WIN32) && !defined(__CYGWIN__)
-    #define timegm(x) _mkgmtime(x)
-    #endif
-    /* timegm() might not be available, and mktime() is sensitive to TZ */
     x.tm_year-= 1900;
     x.tm_mon -= 1;
-    time_t t = timegm(&d);
+    time_t t = http_date_timegm(&x);
     return (t != (time_t)-1) ? t + offset : t;
-   #else
-    int y = x.tm_year;
-    int m = x.tm_mon;
-    int d = x.tm_mday;
-    /* days_from_civil() http://howardhinnant.github.io/date_algorithms.html */
-    y -= m <= 2;
-    int era = y / 400;
-    int yoe = y - era * 400;                                   // [0, 399]
-    int doy = (153 * (m + (m > 2 ? -3 : 9)) + 2) / 5 + d - 1;  // [0, 365]
-    int doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;           // [0, 146096]
-    int days_since_1970 = era * 146097 + doe - 719468;
-    return 60*(60*(24L*days_since_1970+x.tm_hour)+x.tm_min)+x.tm_sec+offset;
-   #endif
 
   #else