Re: [libvirt] [PATCH 06/10] Add a generic internal API for handling any FD based stream

On 11/02/2010 05:42 AM, Daniel P. Berrange wrote: >> >>> +#include <netinet/in.h> >>> +#include <netinet/tcp.h> >> >> Likewise for HAVE_NETINET_TCP_H. > > Doesn't gnulib take care of TCP socket portability for us ? So far, gnulib provides <netinet/in.h>, but not <netinet/tcp.h>. But what exactly are we using that's only in netinet/tcp.h? It may be easy to port to gnulib, since mingw does have tcp support (sys/un.h is the much harder task, since mingw has no notion of unix sockets).

>>> +static int virFDStreamWrite(virStreamPtr st, const char *bytes, size_t nbytes) >> >> Should this return ssize_t... > > No, this has to return an int, to match the public API calling > convention. Then we have to check for overflow, and explicitly return an error if nbytes > INT_MAX.

>>> + if ((st->flags & VIR_STREAM_NONBLOCK) && >>> + (!S_ISCHR(sb.st_mode) && >>> + !S_ISFIFO(sb.st_mode))) { >> >> Should we also permit S_ISSOCK as an fd that supports reliable >> non-blocking behavior? > > AFAIK, there's no way to open a socket as a path on the > filesystem is there ? So there'd be no way that open(path) > could return an FD for which S_ISSOCK() is true. You're probably right that it's not possible to bind a socket to a standard file system. But it is possible via procfs (think /proc/nnn/fd/nnn of a process which already has a socket open), and there might also be some magic /dev/ or /sys/ mappings that can provide a socket (at any rate, bash provides magic handling of /dev/tcp/host/port, whether or not the kernel also has a magic filesystem to provide that support automatically). So it boils down to a question of whether we want to permit or reject sockets, on the pre-condition that the user finds a way to hand us a filename that resolves to a socket.