From: Theo Buehler <tb@theobuehler.org>
Subject: Re: rpki-client: set output files' modification time to be the buildtime
To: Job Snijders <job@openbsd.org>
Cc: tech@openbsd.org
Date: Fri, 31 Oct 2025 05:47:51 +0100

On Thu, Oct 30, 2025 at 11:24:56PM +0000, Job Snijders wrote:
> On Thu, Oct 30, 2025 at 09:39:01PM +0100, Theo Buehler wrote:
> > The output.c changes except the one in outputheader() are largely
> > unrelated and should be done separately. The rest is ok with me.
> 
> ack - below is just the unrelated part
> 
> With this diff the utility sets the "modification time" of the output
> file to be the buildtime timestamp.
> 
> To me this is quite useful in analytics pipelines: moving & archiving
> files using the timestamp from the filesystem instead of having to
> deserialize the file content to find the timestamp shaves off a few
> seconds here and there.
> 
> OK?

Yes, it's all good, I understand. It's just that futimensat() is a
strange and confusing interface with its partially initialized array and
all those magic values... I am also wondering if this dance wants
factoring into a separate helper shared between output.c and repo.c, but
that might obfuscate more than it helps.

ok tb

> 
> Index: output.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/rpki-client/output.c,v
> diff -u -p -r1.43 output.c
> --- output.c	30 Oct 2025 23:18:06 -0000	1.43
> +++ output.c	30 Oct 2025 23:20:08 -0000
> @@ -76,7 +76,7 @@ static const struct outputs {
>  
>  static FILE	*output_createtmp(char *);
>  static void	 output_cleantmp(void);
> -static int	 output_finish(FILE *);
> +static int	 output_finish(FILE *, time_t);
>  static void	 sig_handler(int);
>  static void	 set_signal_handler(void);
>  
> @@ -152,7 +152,7 @@ outputfiles(struct validation_data *vd, 
>  			rc = 1;
>  			continue;
>  		}
> -		if (output_finish(fout) != 0) {
> +		if (output_finish(fout, vd->buildtime) != 0) {
>  			warn("finish for %s format failed", outputs[i].name);
>  			output_cleantmp();
>  			rc = 1;
> @@ -187,12 +187,23 @@ output_createtmp(char *name)
>  }
>  
>  static int
> -output_finish(FILE *out)
> +output_finish(FILE *out, time_t buildtime)
>  {
> +	struct timespec ts[2];
> +
>  	if (fclose(out) != 0)
>  		return -1;
> +
> +	ts[0].tv_nsec = UTIME_OMIT;
> +	ts[1].tv_sec = buildtime;
> +	ts[1].tv_nsec = 0;
> +
> +	if (utimensat(AT_FDCWD, output_tmpname, ts, 0) == -1)
> +		return -1;
> +
>  	if (rename(output_tmpname, output_name) == -1)
>  		return -1;
> +
>  	output_tmpname[0] = '\0';
>  	return 0;
>  }