Re: [PATCH 57/67] receive-pack: simplify keep_arg computation

> To generate "--keep=receive-pack $pid on $host", we write
> progressively into a single buffer, which requires keeping
> track of how much we've written so far. But since the result
> is destined to go into our argv array, we can simply use
> argv_array_pushf.
>
> Unfortunately we still have to have a static buffer for the

> gethostname() call, but at least it now doesn't involve any
> extra size computation. And as a bonus, we drop an sprintf
> and a strcpy call.
>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
> diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
> index 8b50e48..2c82274 100644
> --- a/builtin/receive-pack.c
> +++ b/builtin/receive-pack.c
> @@ -1524,15 +1524,18 @@ static const char *unpack(int err_fd, struct shallow_info *si)
>                 if (status)
>                         return "unpack-objects abnormal exit";
>         } else {
> -               int s;
> -               char keep_arg[256];
> -
> -               s = sprintf(keep_arg, "--keep=receive-pack %"PRIuMAX" on ", (uintmax_t) getpid());
> -               if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
> -                       strcpy(keep_arg + s, "localhost");
> +               char hostname[256];
>
>                 argv_array_pushl(&child.args, "index-pack",
> -                                "--stdin", hdr_arg, keep_arg, NULL);
> +                                "--stdin", hdr_arg, NULL);
> +
> +               if (gethostname(hostname, sizeof(hostname)))
> +                       xsnprintf(hostname, sizeof(hostname), "localhost");
> +               argv_array_pushf(&child.args,
> +                                "--keep=receive-pack %"PRIuMAX" on %s",
> +                                (uintmax_t)getpid(),
> +                                hostname);
> +
>                 if (fsck_objects)
>                         argv_array_pushf(&child.args, "--strict%s",
>                                 fsck_msg_types.buf);
> --
> 2.6.0.rc2.408.ga2926b9