Re: [Qemu-devel] [PATCH v2 3/4] linux-user: add a function hook to translate sockaddr

[Peter Maydell]

On 28 October 2015 at 19:13, Laurent Vivier <address@hidden> wrote:
> Signed-off-by: Laurent Vivier <address@hidden>
> ---
>  linux-user/syscall.c | 41 ++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 36 insertions(+), 5 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 41b85b4..31b5c2c 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -296,9 +296,11 @@ static bitmask_transtbl fcntl_flags_tbl[] = {
>  };
>
>  typedef abi_long (*TargetFdDataFunc)(void *, size_t);
> +typedef abi_long (*TargetFdAddrFunc)(void *, abi_ulong, socklen_t);
>  typedef struct TargetFdTrans {
>      TargetFdDataFunc host_to_target_data;
>      TargetFdDataFunc target_to_host_data;
> +    TargetFdAddrFunc target_to_host_addr;
>  } TargetFdTrans;
>
>  static TargetFdTrans **target_fd_trans;
> @@ -313,6 +315,14 @@ static TargetFdDataFunc fd_trans_host_to_target_data(int 
> fd)
>      return NULL;
>  }
>
> +static TargetFdAddrFunc fd_trans_target_to_host_addr(int fd)
> +{
> +    if (fd < target_fd_max && target_fd_trans[fd]) {
> +        return target_fd_trans[fd]->target_to_host_addr;
> +    }
> +    return NULL;

This should probably do something sensible with a negative
input (either assert, or return NULL, I guess).

> +}
> +
>  static void fd_trans_register(int fd, TargetFdTrans *trans)
>  {
>      unsigned int oldmax;
> @@ -2115,7 +2125,12 @@ static abi_long do_bind(int sockfd, abi_ulong 
> target_addr,
>
>      addr = alloca(addrlen+1);
>
> -    ret = target_to_host_sockaddr(addr, target_addr, addrlen);
> +    if (fd_trans_target_to_host_addr(sockfd)) {
> +        ret = fd_trans_target_to_host_addr(sockfd)(addr, target_addr,
> +                                                   addrlen);
> +    } else {
> +        ret = target_to_host_sockaddr(addr, target_addr, addrlen);
> +    }
>      if (ret)
>          return ret;
>
> @@ -2135,7 +2150,12 @@ static abi_long do_connect(int sockfd, abi_ulong 
> target_addr,
>
>      addr = alloca(addrlen+1);
>
> -    ret = target_to_host_sockaddr(addr, target_addr, addrlen);
> +    if (fd_trans_target_to_host_addr(sockfd)) {
> +        ret = fd_trans_target_to_host_addr(sockfd)(addr, target_addr,
> +                                                   addrlen);
> +    } else {
> +        ret = target_to_host_sockaddr(addr, target_addr, addrlen);
> +    }
>      if (ret)
>          return ret;
>
> @@ -2155,8 +2175,14 @@ static abi_long do_sendrecvmsg_locked(int fd, struct 
> target_msghdr *msgp,
>      if (msgp->msg_name) {
>          msg.msg_namelen = tswap32(msgp->msg_namelen);
>          msg.msg_name = alloca(msg.msg_namelen+1);
> -        ret = target_to_host_sockaddr(msg.msg_name, tswapal(msgp->msg_name),
> -                                msg.msg_namelen);
> +        if (fd_trans_target_to_host_addr(fd)) {
> +            ret = fd_trans_target_to_host_addr(fd)(msg.msg_name,
> +                                                   tswapal(msgp->msg_name),
> +                                                   msg.msg_namelen);
> +        } else {
> +            ret = target_to_host_sockaddr(msg.msg_name, 
> tswapal(msgp->msg_name),
> +                                          msg.msg_namelen);
> +        }
>          if (ret) {
>              goto out2;
>          }
> @@ -2418,7 +2444,12 @@ static abi_long do_sendto(int fd, abi_ulong msg, 
> size_t len, int flags,
>          return -TARGET_EFAULT;
>      if (target_addr) {
>          addr = alloca(addrlen+1);
> -        ret = target_to_host_sockaddr(addr, target_addr, addrlen);
> +        if (fd_trans_target_to_host_addr(fd)) {
> +            ret = fd_trans_target_to_host_addr(fd)(addr, target_addr,
> +                                                   addrlen);
> +        } else {
> +            ret = target_to_host_sockaddr(addr, target_addr, addrlen);
> +        }
>          if (ret) {
>              unlock_user(host_msg, msg, 0);
>              return ret;

The repetition here suggests we should pass the fd into
target_to_host_sockaddr and do the handling of
fd_trans_target_to_host_addr there.

thanks
-- PMM