[PATCH v2 7/7] Do not use date.c:tm_to_time_t() from compat/mingw.c
From: Johannes Sixt <hidden>
Date: 2016-06-15 22:48:02
Subsystem:
the rest · Maintainer:
Linus Torvalds
To implement gettimeofday(), a broken-down UTC time was requested from the system using GetSystemTime(), then tm_to_time_t() was used to convert it to a time_t because it does not look at the current timezone, which mktime() would do. Use GetSystemTimeAsFileTime() and a different conversion path to avoid this back-reference from the compatibility layer to the generic code. Signed-off-by: Johannes Sixt <redacted> --- This is new. It was triggered by Junio's "mark function static" series. The patch that I sent out in response there was too simple to be correct. compat/mingw.c | 36 +++++++++++++++++++----------------- 1 files changed, 19 insertions(+), 17 deletions(-)
diff --git a/compat/mingw.c b/compat/mingw.c
index 74ffc18..ab65f77 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c@@ -140,12 +140,20 @@ int mingw_open (const char *filename, int oflags, ...) return fd; } -static inline time_t filetime_to_time_t(const FILETIME *ft) +/* + * The unit of FILETIME is 100-nanoseconds since January 1, 1601, UTC. + * Returns the 100-nanoseconds ("hekto nanoseconds") since the epoch. + */ +static inline long long filetime_to_hnsec(const FILETIME *ft) { long long winTime = ((long long)ft->dwHighDateTime << 32) + ft->dwLowDateTime; - winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */ - winTime /= 10000000; /* Nano to seconds resolution */ - return (time_t)winTime; + /* Windows to Unix Epoch conversion */ + return winTime - 116444736000000000LL; +} + +static inline time_t filetime_to_time_t(const FILETIME *ft) +{ + return (time_t)(filetime_to_hnsec(ft) / 10000000); } /* We keep the do_lstat code in a separate function to avoid recursion.
@@ -281,19 +289,13 @@ int mkstemp(char *template) int gettimeofday(struct timeval *tv, void *tz) { - SYSTEMTIME st; - struct tm tm; - GetSystemTime(&st); - tm.tm_year = st.wYear-1900; - tm.tm_mon = st.wMonth-1; - tm.tm_mday = st.wDay; - tm.tm_hour = st.wHour; - tm.tm_min = st.wMinute; - tm.tm_sec = st.wSecond; - tv->tv_sec = tm_to_time_t(&tm); - if (tv->tv_sec < 0) - return -1; - tv->tv_usec = st.wMilliseconds*1000; + FILETIME ft; + long long hnsec; + + GetSystemTimeAsFileTime(&ft); + hnsec = filetime_to_hnsec(&ft); + tv->tv_sec = hnsec / 10000000; + tv->tv_usec = (hnsec % 10000000) / 10; return 0; }
--
1.6.6.218.g3e6eb