[PATCH 07 of 14] chg: use openat instead of open when creating the lock file

[Yuya Nishihara]

On Mon, 11 Apr 2016 00:57:24 +0100, Jun Wu wrote:
> # HG changeset patch
> # User Jun Wu <quark at fb.com>
> # Date 1460327930 -3600
> #      Sun Apr 10 23:38:50 2016 +0100
> # Node ID 4616bceaa941b40b39055610ba109252dee3a20c
> # Parent  a0233eac2848926116ecbdb4bf44fd5f066d7f1d
> chg: use openat instead of open when creating the lock file
> 
> This is a part of the series to support long socket path. Since we will switch
> to basename for the lock file soon, use openat instead of open to make sure
> it is created inside the directory.
> 
> diff --git a/contrib/chg/chg.c b/contrib/chg/chg.c
> --- a/contrib/chg/chg.c
> +++ b/contrib/chg/chg.c
> @@ -174,8 +174,8 @@
>  static void lockcmdserver(struct cmdserveropts *opts)
>  {
>  	if (opts->lockfd == -1) {
> -		opts->lockfd = open(opts->lockfile,
> -				    O_RDWR | O_CREAT | O_NOFOLLOW, 0600);
> +		opts->lockfd = openat(opts->sockdirfd, opts->lockfile,
> +				      O_RDWR | O_CREAT | O_NOFOLLOW, 0600);

It appears that openat() was introduced in Mac OS X 10.10, which seems too
new to use without compatibility layer.