Re: [PATCH v2 1/2] t: add a test helper to truncate files

[Jeff King <peff@peff.net>]

On Thu, Oct 12, 2023 at 04:09:29PM +0000, brian m. carlson wrote:

> +int cmd__truncate(int argc, const char **argv)
> +{
> +	char *p = NULL;
> +	uintmax_t sz = 0;
> +	int fd = -1;
> +
> +	if (argc != 3)
> +		die("expected filename and size");
> +
> +	sz = strtoumax(argv[2], &p, 0);
> +	if (*p)
> +		die("invalid size");
> +
> +	fd = open(argv[1], O_WRONLY | O_CREAT, 0600);
> +	if (fd < 0)
> +		die_errno("failed to open file %s", argv[1]);
> +
> +	if (ftruncate(fd, (off_t) sz) < 0)
> +		die_errno("failed to truncate file");
> +	return 0;
> +}

Coverity flagged this as leaking the descriptor "fd" (which is obviously
true). I guess it doesn't matter much in practice, since we're exiting
the process directly afterwards. If it were a memory leak we'd free() it
anyway to shut up the leak detector, but I don't know if we want to be
as careful here (in theory it creates noise that distracts from real
problems, but Coverity is noisy enough that I don't even bother looking
at existing problems).

-Peff