On Thursday 03 March 2011 5:08:10 pm Stefan Hajnoczi wrote:
> On Mon, Feb 28, 2011 at 11:22 AM, M. Mohan Kumar <mo...@in.ibm.com> wrote:
> > + retval = recvmsg(sockfd, &msg, 0);
> > + if (retval < 0) {
> > + *sock_error = 1;
> > + return -EIO;
> > + }
>
> Are we guaranteed this will be called with signals blocked? Otherwise
> we need to handle EINTR.
Ok
>
> > + if (fd_info.fi_flags & FI_FD_SOCKERR) {
> > + *sock_error = 1;
> > + return -EIO;
> > + }
> > + /* If fd is invalid, ancillary data is not present */
> > + if (fd_info.fi_fd < 0 || fd_info.fi_flags & FI_FD_INVALID) {
> > + return fd_info.fi_fd;
> > + }
>
> Testing fd_info.fi_flags & FI_FD_INVALID looks dangerous to me. If
> for some reason fi_fd >= 0 then we'd return success here. fd_fd < 0
> should be a sufficient check, perhaps you wanted an assert() instead?
This check is required because,
Creating special objects like directory, device nodes will not have a valid
fd, usually fd will be 0 on success and -ve on error. During success cases, we
can't do sendmsg for fd=0 value with SCM_RIGHTS, that would result in problem.
In this case, we set fd_info.fi_flags to FI_FD_INVALID indicating fd is not a
valid one, but its not an error case also.
----
M. Mohan Kumar
