is futimens and UTIME_OMIT supported

[EvenOAndersen]

I am getting strange values (1, 73000), I think.

#include <sys/stat.h>
#include <errno.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <math.h>

int mkdir(const char *pathname, mode_t mode);

void issue_timecall(int fd, struct timespec *times)
{
	int status0 = 0;
	if (times)
		status0 = futimens(fd, times);

	struct stat stat_buf;
	const int status1 = fstat(fd, &stat_buf);

	fprintf(stdout, "fd %d, status0 %d status1 %d ctime %lld %lld mtime %lld %lld atime %lld %lld\n",
		fd,
		status0,
		status1,
		(long long)stat_buf.st_ctim.tv_sec,           // from times[1], when times[1] is older
		(long long)stat_buf.st_ctim.tv_nsec,
		(long long)stat_buf.st_mtim.tv_sec, 	// from times[1]
		(long long)stat_buf.st_mtim.tv_nsec,
		(long long)stat_buf.st_atim.tv_sec,    	// from times[0]
		(long long)stat_buf.st_atim.tv_nsec);

}

int main()
{
	int fd = open("/tmp/time.txt", O_RDWR|O_CREAT, 0644);
	struct timespec times[2];

	issue_timecall(fd, nullptr); // displays sensible values

	times[0].tv_sec=0;
	times[0].tv_nsec=UTIME_OMIT;
	times[1].tv_sec=0;
	times[1].tv_nsec=UTIME_OMIT;

	issue_timecall(fd, times); // (1, 73000) for all timestamps

	times[0].tv_sec=-pow(2, 31);
	times[0].tv_nsec=0;
	issue_timecall(fd, times); // (1, 73000) for all timestamps even if we set the access time

	times[1].tv_sec=-pow(2, 31);
	times[1].tv_nsec=0;
	issue_timecall(fd, times); // As expected
}

Output:

fd 3, status0 0 status1 0 ctime 1723207362 385000 mtime 1723207362 385000 atime 1723207362 385000
fd 3, status0 0 status1 0 ctime 1 73000 mtime 1 73000 atime 1 73000
fd 3, status0 0 status1 0 ctime 1 73000 mtime 1 73000 atime 1 73000
fd 3, status0 0 status1 0 ctime -2147483648 0 mtime -2147483648 0 atime -2147483648 0

[sbc100]

Wow, TIL about UTIME_OMIT and UTIME_NOW. Still learning more corners of the C std library after 25 years... Looks like we just didn't implement these on the JS side yet.

[sbc100]

This was fixed in #22459