Re: [libvirt] [PATCH] safe{read, write}: Don't lie on nonblocking FD

Currently, whenever somebody calls saferead() on nonblocking FD (safewrite() is totally interchangeable for purpose of this message) he might get wrong return value. For instance, in the first iteration some data is read. The number of bytes read is stored into local variable 'nread'. However, in next iterations we can get -1 from read() with errno == EAGAIN, in which case the -1 is returned despite fact some data has already been read. So the caller gets confused. Moreover, the comment just above the functions says, they act like regular read() with nicer handling of EINTR. Well, they don't now.