Re: [libvirt] PATCH: Allow specific FDs to be kept open in virExec()

On Fri, Aug 22, 2008 at 09:22:06AM +0100, Richard W.M. Jones wrote: > On Thu, Aug 21, 2008 at 02:58:30PM +0100, Daniel P. Berrange wrote: > > +#define VIR_EXEC_FDSET_SIZE() (sysconf(_SC_OPEN_MAX)/8) > > +#define VIR_EXEC_FDSET_CLEAR(set) memset((set), 0, VIR_EXEC_FDSET_SIZE()) > > +#define VIR_EXEC_FDSET_ON(set, fd) (set[(fd)/8] |= (1 << ((fd)%8))) > > +#define VIR_EXEC_FDSET_OFF(set, fd) (set[(fd)/8] &= ~(1 << ((fd)%8))) > > +#define VIR_EXEC_FDSET_ISON(set, fd) (set[(fd)/8] & (1 << ((fd)%8))) > > +1 although I'm interested to know why you didn't just use ordinary > FD_SETs for this. For some reason I have it in my head that fd_set was limited to 32 but looking at the Linux source its clearly 1024, which is the sme as my _SC_OPEN_MAX. The manpage says its FD_SETSIZE, but doesn't clarify whether FD_SETSIZE is guarenteed to be large enough to store any FD upto _SC_OPEN_MAX. Jim, any thoughts on this ? I'll happily switch to fd_set if we expect it'll be suitable