[PATCH 3 of 3 V2] chg: hold a lock file before connected to server

[Yuya Nishihara]

On Mon, 22 Feb 2016 17:59:09 +0000, Jun Wu wrote:
> # HG changeset patch
> # User Jun Wu <quark at fb.com>
> # Date 1455620932 0
> #      Tue Feb 16 11:08:52 2016 +0000
> # Node ID 43e380f60dd4373090fb94497761ebfdc181ca54
> # Parent  118b386f47cb6e6aa4f231c9ae22bc2e155e7b99
> chg: hold a lock file before connected to server

> +/* Connect to a cmdserver. Will start a new server on demand. */
> +static hgclient_t *connectcmdserver(struct cmdserveropts *opts)
>  {
> -	debugmsg("start cmdserver at %s", opts->sockname);
> +	hgclient_t *hgc = hgc_open(opts->sockname);
> +	if (hgc)
> +		return hgc;
>  
> -	if (lockcmdserver(opts) < 0) {
> -		debugmsg("lock file exists, waiting...");
> -		waitcmdserver(opts, 0);
> -		return;
> +	lockcmdserver(opts);
> +	hgc = hgc_open(opts->sockname);
> +	if (hgc) {
> +		unlockcmdserver(opts);
> +		debugmsg("cmdserver is started by another process");
> +		return hgc;
>  	}
>  
> -	/* remove dead cmdserver socket if any */
> -	unlink(opts->sockname);

unlink() is the only way to recover from server crash, but I expect your future
patches will make it unnecessary. Please let me know if you removed these lines
unintentionally.