Re: [PATCH 8/9] bsd-user: implement sysctlbyname(2)

[Richard Henderson <richard.henderson@linaro.org>]

On 2/10/23 13:18, Warner Losh wrote:
> From: Kyle Evans <kevans@FreeBSD.org>
> 
> do_freebsd_sysctlbyname needs to translate the 'name' back down to a OID
> so we can intercept the special ones. Do that and call the common wrapper
> do_freebsd_sysctl_oid.
> 
> Signed-off-by: Kyle Evans <kevans@FreeBSD.org>
> Signed-off-by: Warner Losh <imp@bsdimp.com>
> ---
>   bsd-user/freebsd/os-sys.c     | 58 +++++++++++++++++++++++++++++++++++
>   bsd-user/freebsd/os-syscall.c |  4 +++
>   2 files changed, 62 insertions(+)
> 
> diff --git a/bsd-user/freebsd/os-sys.c b/bsd-user/freebsd/os-sys.c
> index 13736936e5f..62c729dfe47 100644
> --- a/bsd-user/freebsd/os-sys.c
> +++ b/bsd-user/freebsd/os-sys.c
> @@ -345,6 +345,64 @@ out:
>       return ret;
>   }
>   
> +/*
> + * This syscall was created to make sysctlbyname(3) more efficient.
> + * Unfortunately, because we have to fake some sysctls, we can't do that.

Can't do what?  Directly use sysctlbyname?

> +    if (oldlenp) {
> +        if (get_user_ual(oldlen, oldlenp)) {
> +            return -TARGET_EFAULT;
> +        }

Same comment about verifying write early.

> +    unlock_user(holdp, oldp, holdlen);

And writeback vs error.


r~