[tarantool-patches] Re: [PATCH] Replace sendmsg with sendto shortcut

[Maxim Melentiev]

ping Konstantin Osipov, Alexander Turenko

Sorry, forgot to CC in initial email and then pinged in wrong thread.

On 20/08/2019 15:01, Max Melentiev (Redacted sender m.melentiev for 
DMARC) wrote:
> There is a problem with calculating .msg_namelen field
> of msghdr struct. Instead of
>
>      .msg_name   = &sa,
>      .msg_namelen = sizeof(sa.sun_family) + strlen(sd_unix_path),
>
> it must set as
>
>      .msg_namelen = sizeof(sa) // larger value than current invalid one
>
> It works on linux but when I tried to enable this feature for macOS
> it didn't (maybe because of different order of fields in the struct).
>
> Instead of fixing calculation, I've replaced original sendmsg call
> with sendto, because it's a convenient shortcut which
> simplifies code and can prevent such mistakes.
> ---
>
> Preview: https://github.com/printercu/tarantool/commit/bc30b1093be1d03507bf84ca218b03bec5e0244a
>
>   src/systemd.c | 13 ++-----------
>   1 file changed, 2 insertions(+), 11 deletions(-)
>
> diff --git a/src/systemd.c b/src/systemd.c
> index b6c48afe2..9c0a26dd2 100644
> --- a/src/systemd.c
> +++ b/src/systemd.c
> @@ -100,23 +100,14 @@ int systemd_notify(const char *message) {
>   	struct sockaddr_un sa = {
>   		.sun_family = AF_UNIX,
>   	};
> -	struct iovec vec = {
> -		.iov_base = (char  *)message,
> -		.iov_len  = (size_t )strlen(message)
> -	};
> -	struct msghdr msg = {
> -		.msg_iov    = &vec,
> -		.msg_iovlen = 1,
> -		.msg_name   = &sa,
> -	};
>
> -	msg.msg_namelen = sizeof(sa.sun_family) + strlen(sd_unix_path);
>   	strncpy(sa.sun_path, sd_unix_path, sizeof(sa.sun_path));
>   	if (sa.sun_path[0] == '@')
>   		sa.sun_path[0] = '\0';
>
>   	say_debug("systemd: sending message '%s'", message);
> -	ssize_t sent = sendmsg(systemd_fd, &msg, MSG_NOSIGNAL);
> +	ssize_t sent = sendto(systemd_fd, message, (size_t)strlen(message),
> +		MSG_NOSIGNAL, (struct sockaddr*)&sa, sizeof(sa));
>   	if (sent == -1) {
>   		say_syserror("systemd: failed to send message");
>   		return -1;
> --
> 2.21.0
>
>
> .
>