Re: [Qemu-devel] [PATCH v4 1/7] qemu-char: Add MSG_CMSG_CLOEXEC flag to recvmsg

[Eric Blake]

On 06/22/2012 12:36 PM, Corey Bryant wrote:
> This sets the close-on-exec flag for the file descriptor received
> via SCM_RIGHTS.
> 
> Signed-off-by: Corey Bryant <address@hidden>
> ---
> v4
>  -This patch is new in v4 (address@hidden)
> 
>  qemu-char.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/qemu-char.c b/qemu-char.c
> index c2aaaee..f890113 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -2263,7 +2263,7 @@ static ssize_t tcp_chr_recv(CharDriverState *chr, char 
> *buf, size_t len)
>      msg.msg_control = &msg_control;
>      msg.msg_controllen = sizeof(msg_control);
>  
> -    ret = recvmsg(s->fd, &msg, 0);
> +    ret = recvmsg(s->fd, &msg, MSG_CMSG_CLOEXEC);

MSG_CMSG_CLOEXEC is not (yet) in POSIX (although it has been proposed
for addition); therefore, at the moment, it only exists on Linux and
Cygwin.  Does this need to have conditional code to allow compilation on
BSD, such as:

#ifndef MSG_CMSG_CLOEXEC
# define MSG_CMSG_CLOEXEC 0
#endif

as well as fallback code that sets FD_CLOEXEC manually via fcntl() when
MSG_CMSG_CLOEXEC is missing?

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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