xtime: Call tzset() from main() instead of lazily

POSIX specifies[1] that

    If a thread accesses tzname, daylight, or timezone directly while
    another thread is in a call to tzset(), or to any function that is
    required or allowed to set timezone information as if by calling
    tzset(), the behavior is undefined.

So calling it lazily from arbitrary threads is risky.

[1]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/tzset.html

1 files changed, 1 insertions, 33 deletions

diff --git a/src/xtime.c b/src/xtime.c
index 4309289..8100f6c 100644
--- a/src/xtime.c
+++ b/src/xtime.c
@@ -11,38 +11,6 @@
 #include <time.h>
 #include <unistd.h>
 
-/** Call tzset() if necessary. */
-static void xtzset(void) {
-	static atomic bool is_set = false;
-
-	if (!load(&is_set, relaxed)) {
-		tzset();
-		store(&is_set, true, relaxed);
-	}
-}
-
-int xlocaltime(const time_t *timep, struct tm *result) {
-	// Should be called before localtime_r() according to POSIX.1-2004
-	xtzset();
-
-	if (localtime_r(timep, result)) {
-		return 0;
-	} else {
-		return -1;
-	}
-}
-
-int xgmtime(const time_t *timep, struct tm *result) {
-	// Should be called before gmtime_r() according to POSIX.1-2004
-	xtzset();
-
-	if (gmtime_r(timep, result)) {
-		return 0;
-	} else {
-		return -1;
-	}
-}
-
 int xmktime(struct tm *tm, time_t *timep) {
 	*timep = mktime(tm);
 
@@ -50,7 +18,7 @@ int xmktime(struct tm *tm, time_t *timep) {
 		int error = errno;
 
 		struct tm tmp;
-		if (xlocaltime(timep, &tmp) != 0) {
+		if (!localtime_r(timep, &tmp)) {
 			return -1;
 		}