Re: [PATCH 15/22] bsd-user/freebsd/os-syscall.c: unlock_iovec

[Richard Henderson]

On 2/1/22 22:14, Warner Losh wrote:
> Releases the references to the iovec created by lock_iovec.
>
> Signed-off-by: Warner Losh <imp@bsdimp.com>
> ---
>   bsd-user/freebsd/os-syscall.c | 23 +++++++++++++++++++++++
>   1 file changed, 23 insertions(+)
>
> diff --git a/bsd-user/freebsd/os-syscall.c b/bsd-user/freebsd/os-syscall.c
> index c21759ae7ce..d49945f0fcc 100644
> --- a/bsd-user/freebsd/os-syscall.c
> +++ b/bsd-user/freebsd/os-syscall.c
> @@ -167,6 +167,29 @@ struct iovec *lock_iovec(int type, abi_ulong target_addr,
>       return NULL;
>   }
>   
> +void unlock_iovec(struct iovec *vec, abi_ulong target_addr,
> +        int count, int copy)
> +{
> +    struct target_iovec *target_vec;
> +    int i;
> +
> +    target_vec = lock_user(VERIFY_READ, target_addr,
> +                           count * sizeof(struct target_iovec), 1);
> +    if (target_vec) {
> +        for (i = 0; i < count; i++) {
> +            abi_ulong base = tswapal(target_vec[i].iov_base);
> +            abi_long len = tswapal(target_vec[i].iov_len);
> +            if (len < 0) {
> +                break;
> +            }
> +            unlock_user(vec[i].iov_base, base, copy ? vec[i].iov_len : 0);
> +        }
> +        unlock_user(target_vec, target_addr, 0);

Not quite right.  Any vec[i].iov_len == 0 ought to be skipped, as per the previous patch, 
where we force those values for bad_address and target_vec[i].iov_len == 0.


r~