Use localtime_r instead of localtime, including a Windows implementation that handles Win64's broken struct timeval.tv_sec

compat.h

@@ -53,6 +53,26 @@
    } while (0)
  #endif
 
+// localtime is thread-safe on Windows
+// We also use this with timeval.tv_sec, which is incorrectly smaller than time_t on Windows
+// Need to cast to time_t* to suppress warning - actual problem shouldn't be possible in practice
+#define localtime_r(timep, result)  (  \
+	memcpy(result,  \
+		(  \
+			(sizeof(*timep) == sizeof(time_t))  \
+			? localtime((time_t*)timep)  \
+			: localtime_convert(*timep)  \
+		),  \
+		sizeof(*result)  \
+	)  \
+)
+
+static inline
+struct tm *localtime_convert(time_t t)
+{
+	return localtime(&t);
+}
+
 static inline int nanosleep(const struct timespec *req, struct timespec *rem)
 {
 	struct timeval tstart;

logging.c

@@ -11,6 +11,7 @@
 
 #include <unistd.h>
 
+#include "compat.h"
 #include "logging.h"
 #include "miner.h"
 
@@ -92,11 +93,12 @@ static void log_generic(int prio, const char *fmt, va_list ap)
 		char *f;
 		int len;
 		struct timeval tv = {0, 0};
-		struct tm *tm;
+		struct tm _tm;
+		struct tm *tm = &_tm;
 
 		gettimeofday(&tv, NULL);
 
-		tm = localtime(&tv.tv_sec);
+		localtime_r(&tv.tv_sec, tm);
 
 		len = 40 + strlen(fmt) + 22;
 		f = alloca(len);

miner.c

@@ -345,7 +345,7 @@ static bool should_run(void)
 		return true;
 
 	gettimeofday(&tv, NULL);
-	tm = *localtime(&tv.tv_sec);
+	localtime_r(&tv.tv_sec, &tm);
 
 	// NOTE: This is delicately balanced so that should_run is always false if schedstart==schedstop
 	if (time_before(&schedstop.tm, &schedstart.tm))
@@ -362,9 +362,10 @@ static bool should_run(void)
 
 void get_datestamp(char *f, struct timeval *tv)
 {
-	struct tm *tm;
+	struct tm _tm;
+	struct tm *tm = &_tm;
 
-	tm = localtime(&tv->tv_sec);
+	localtime_r(&tv->tv_sec, tm);
 	sprintf(f, "[%d-%02d-%02d %02d:%02d:%02d]",
 		tm->tm_year + 1900,
 		tm->tm_mon + 1,
@@ -376,9 +377,10 @@ void get_datestamp(char *f, struct timeval *tv)
 
 void get_timestamp(char *f, struct timeval *tv)
 {
-	struct tm *tm;
+	struct tm _tm;
+	struct tm *tm = &_tm;
 
-	tm = localtime(&tv->tv_sec);
+	localtime_r(&tv->tv_sec, tm);
 	sprintf(f, "[%02d:%02d:%02d]",
 		tm->tm_hour,
 		tm->tm_min,
@@ -2727,7 +2729,9 @@ static bool submit_upstream_work_completed(struct work *work, bool resubmit, str
 
 		if (opt_worktime) {
 			char workclone[20];
+			struct tm _tm;
 			struct tm *tm, tm_getwork, tm_submit_reply;
+			tm = &_tm;
 			double getwork_time = tdiff((struct timeval *)&(work->tv_getwork_reply),
 							(struct timeval *)&(work->tv_getwork));
 			double getwork_to_work = tdiff((struct timeval *)&(work->tv_work_start),
@@ -2739,9 +2743,9 @@ static bool submit_upstream_work_completed(struct work *work, bool resubmit, str
 			double submit_time = tdiff(&tv_submit_reply, ptv_submit);
 			int diffplaces = 3;
 
-			tm = localtime(&(work->tv_getwork.tv_sec));
+			localtime_r(&(work->tv_getwork.tv_sec), tm);
 			memcpy(&tm_getwork, tm, sizeof(struct tm));
-			tm = localtime(&(tv_submit_reply.tv_sec));
+			localtime_r(&(tv_submit_reply.tv_sec), tm);
 			memcpy(&tm_submit_reply, tm, sizeof(struct tm));
 
 			if (work->clone) {
@@ -8094,9 +8098,9 @@ begin_bench:
 	gettimeofday(&total_tv_end, NULL);
 	miner_started = total_tv_start;
 	if (schedstart.tm.tm_sec)
-		schedstart.tm = *localtime(&miner_started.tv_sec);
+		localtime_r(&miner_started.tv_sec, &schedstart.tm);
 	if (schedstop.tm.tm_sec)
-		schedstop .tm = *localtime(&miner_started.tv_sec);
+		localtime_r(&miner_started.tv_sec, &schedstop .tm);
 	get_datestamp(datestamp, &total_tv_start);
 
 	// Start threads