Re: [Qemu-devel] [PATCH v6 4/8] linux-user/syscall: Introduce target_sockaddr_nl

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

On Mon, Sep 9, 2019 at 4:23 PM Laurent Vivier <laurent@vivier.eu> wrote:
> Le 08/09/2019 à 08:15, Philippe Mathieu-Daudé a écrit :
> > Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> > Tested-By: Guido Günther <agx@sigxcpu.org>
> > ---
> >  linux-user/syscall.c      | 6 ++++--
> >  linux-user/syscall_defs.h | 7 +++++++
> >  2 files changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> > index 8b41a03901..5128312db5 100644
> > --- a/linux-user/syscall.c
> > +++ b/linux-user/syscall.c
> > @@ -1494,8 +1494,10 @@ static inline abi_long host_to_target_sockaddr(abi_ulong target_addr,
> >          sizeof(target_saddr->sa_family)) {
> >          target_saddr->sa_family = tswap16(addr->sa_family);
> >      }
> > -    if (addr->sa_family == AF_NETLINK && len >= sizeof(struct sockaddr_nl)) {
> > -        struct sockaddr_nl *target_nl = (struct sockaddr_nl *)target_saddr;
> > +    if (addr->sa_family == AF_NETLINK &&
> > +        len >= sizeof(struct target_sockaddr_nl)) {
> > +        struct target_sockaddr_nl *target_nl =
> > +               (struct target_sockaddr_nl *)target_saddr;
> >          target_nl->nl_pid = tswap32(target_nl->nl_pid);
> >          target_nl->nl_groups = tswap32(target_nl->nl_groups);
> >      } else if (addr->sa_family == AF_PACKET) {
> > diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> > index 0662270300..fcedd0d0fb 100644
> > --- a/linux-user/syscall_defs.h
> > +++ b/linux-user/syscall_defs.h
> > @@ -153,6 +153,13 @@ struct target_sockaddr_un {
> >      uint8_t sun_path[108];
> >  };
> >
> > +struct target_sockaddr_nl {
> > +    uint16_t nl_family;     /* AF_NETLINK */
> > +    uint16_t __pad;
> > +    uint32_t nl_pid;
> > +    uint32_t nl_groups;
> > +};
>
> You should use abi_ushort and abi_uint to keep alignments good (for
> instance m68k aligns on 16bit whereas others on 32bit).

Are you sure? The other target_sockaddr don't use that...
Is this because netlink is a host-only structure? (while other are
serialized over some interface).

Thanks,

Phil.