Merge branch 'dd/time-reentrancy'

Avoid gmtime() and localtime() and prefer their reentrant
counterparts.

* dd/time-reentrancy:
  mingw: use {gm,local}time_s as backend for {gm,local}time_r
  archive-zip.c: switch to reentrant localtime_r
  date.c: switch to reentrant {gm,local}time_r

3 files changed, 21 insertions, 19 deletions

diff --git a/archive-zip.c b/archive-zip.c
index 4d66b5be6e..313c6b9c46 100644
--- a/archive-zip.c
+++ b/archive-zip.c
@@ -603,18 +603,18 @@ static void write_zip_trailer(const struct object_id *oid)
 static void dos_time(timestamp_t *timestamp, int *dos_date, int *dos_time)
 {
 	time_t time;
-	struct tm *t;
+	struct tm tm;
 
 	if (date_overflows(*timestamp))
 		die(_("timestamp too large for this system: %"PRItime),
 		    *timestamp);
 	time = (time_t)*timestamp;
-	t = localtime(&time);
+	localtime_r(&time, &tm);
 	*timestamp = time;
 
-	*dos_date = t->tm_mday + (t->tm_mon + 1) * 32 +
-	            (t->tm_year + 1900 - 1980) * 512;
-	*dos_time = t->tm_sec / 2 + t->tm_min * 32 + t->tm_hour * 2048;
+	*dos_date = tm.tm_mday + (tm.tm_mon + 1) * 32 +
+		    (tm.tm_year + 1900 - 1980) * 512;
+	*dos_time = tm.tm_sec / 2 + tm.tm_min * 32 + tm.tm_hour * 2048;
 }
 
 static int archive_zip_config(const char *var, const char *value, void *data)
diff --git a/compat/mingw.c b/compat/mingw.c
index c2a4835104..76ac8713d2 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -1018,16 +1018,16 @@ int pipe(int filedes[2])
 
 struct tm *gmtime_r(const time_t *timep, struct tm *result)
 {
-	/* gmtime() in MSVCRT.DLL is thread-safe, but not reentrant */
-	memcpy(result, gmtime(timep), sizeof(struct tm));
-	return result;
+	if (gmtime_s(result, timep) == 0)
+		return result;
+	return NULL;
 }
 
 struct tm *localtime_r(const time_t *timep, struct tm *result)
 {
-	/* localtime() in MSVCRT.DLL is thread-safe, but not reentrant */
-	memcpy(result, localtime(timep), sizeof(struct tm));
-	return result;
+	if (localtime_s(result, timep) == 0)
+		return result;
+	return NULL;
 }
 
 char *mingw_getcwd(char *pointer, int len)
diff --git a/date.c b/date.c
index 041db7db4e..b0d9a8421d 100644
--- a/date.c
+++ b/date.c
@@ -64,16 +64,16 @@ static time_t gm_time_t(timestamp_t time, int tz)
  * thing, which means that tz -0100 is passed in as the integer -100,
  * even though it means "sixty minutes off"
  */
-static struct tm *time_to_tm(timestamp_t time, int tz)
+static struct tm *time_to_tm(timestamp_t time, int tz, struct tm *tm)
 {
 	time_t t = gm_time_t(time, tz);
-	return gmtime(&t);
+	return gmtime_r(&t, tm);
 }
 
-static struct tm *time_to_tm_local(timestamp_t time)
+static struct tm *time_to_tm_local(timestamp_t time, struct tm *tm)
 {
 	time_t t = time;
-	return localtime(&t);
+	return localtime_r(&t, tm);
 }
 
 /*
@@ -283,6 +283,7 @@ static void show_date_normal(struct strbuf *buf, timestamp_t time, struct tm *tm
 const char *show_date(timestamp_t time, int tz, const struct date_mode *mode)
 {
 	struct tm *tm;
+	struct tm tmbuf = { 0 };
 	struct tm human_tm = { 0 };
 	int human_tz = -1;
 	static struct strbuf timebuf = STRBUF_INIT;
@@ -318,11 +319,11 @@ const char *show_date(timestamp_t time, int tz, const struct date_mode *mode)
 	}
 
 	if (mode->local)
-		tm = time_to_tm_local(time);
+		tm = time_to_tm_local(time, &tmbuf);
 	else
-		tm = time_to_tm(time, tz);
+		tm = time_to_tm(time, tz, &tmbuf);
 	if (!tm) {
-		tm = time_to_tm(0, 0);
+		tm = time_to_tm(0, 0, &tmbuf);
 		tz = 0;
 	}
 
@@ -959,10 +960,11 @@ void datestamp(struct strbuf *out)
 {
 	time_t now;
 	int offset;
+	struct tm tm = { 0 };
 
 	time(&now);
 
-	offset = tm_to_time_t(localtime(&now)) - now;
+	offset = tm_to_time_t(localtime_r(&now, &tm)) - now;
 	offset /= 60;
 
 	date_string(now, offset, out);