Re: [chrony-dev] [PATCH] Add -N option for s6-style service readiness notification

[Miroslav Lichvar <mlichvar@xxxxxxxxxx>]

On Thu, Apr 09, 2026 at 11:15:35AM +0000, Emery Hemingway wrote:
> https://skarnet.org/software/s6/notifywhenup.html

Can you please describe it in a sentence how the notification works,
or copy the description from the man page?

> --- a/doc/chronyd.adoc
> +++ b/doc/chronyd.adoc
> @@ -201,6 +201,10 @@ still track its offset and frequency relative to the estimated true time. This
>  option allows *chronyd* to be started without the capability to adjust or set
>  the system clock (e.g. in some containers) to operate as an NTP server.
>  
> +*-N* _fd_::
> +This options declares a file-descriptor that a process supervisor is reading
> +for an s6-style service ready notification.

There should be no hyphen in "file-descriptor"?

> @@ -110,6 +112,11 @@ delete_pidfile(void)
>  static void
>  notify_system_manager(int start)
>  {
> +  if (start && notify_fd) {
> +    dprintf(notify_fd, "\n");
> +    close(notify_fd);
> +  }

dprintf() doesn't seem portable. write() would be better.

> +
>  #ifdef LINUX
>    /* The systemd protocol is documented in the sd_notify(3) man page */
>    const char *message, *path = getenv("NOTIFY_SOCKET");
> @@ -454,6 +461,7 @@ print_help(const char *progname)
>               "  -P PRIORITY\tSet process priority (0)\n"
>               "  -m\t\tLock memory\n"
>               "  -x\t\tDon't control clock\n"
> +             "  -N FD\tnotify supervisor on an open file-descriptor\n"

I would prefer shorter "Notify supervisor" here. More details are in
the man page.

>               "  -v, --version\tPrint version and exit\n"
>               "  -h, --help\tPrint usage and exit\n",
>               progname, DEFAULT_CONF_FILE, DEFAULT_USER);
> @@ -512,7 +520,7 @@ int main
>    optind = 1;
>  
>    /* Parse short command-line options */
> -  while ((opt = getopt(argc, argv, "46df:F:hl:L:mnpP:qQrRst:u:Uvx")) != -1) {
> +  while ((opt = getopt(argc, argv, "46df:F:hl:L:mn:N:pP:qQrRst:u:Uvx")) != -1) {

This changes 'n' to accept an argument (extra colon).

Thanks,

-- 
Miroslav Lichvar


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