[libvirt] [PATCH 1/2] socket: preserve real errno when socket/bind calls fail

[Daniel P. Berrangé]

On Tue, Jul 24, 2018 at 05:51:50PM +0200, Jiri Denemark wrote:
> On Tue, Jul 24, 2018 at 15:18:09 +0100, Daniel P. Berrangé wrote:
> > When reporting socket/bind failures we want to ensure any fatal error
> > reported is as accurate as possible. We'll prefer reporting a bind()
> > errno over a socket() errno, because if socket() works but bind() fails
> > that is a more significant event.
> > 
> > Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> > ---
> >  src/rpc/virnetsocket.c | 24 ++++++++++++------------
> >  1 file changed, 12 insertions(+), 12 deletions(-)
> > 
> > diff --git a/src/rpc/virnetsocket.c b/src/rpc/virnetsocket.c
> > index fee61ace60..8e04d61e98 100644
> > --- a/src/rpc/virnetsocket.c
> > +++ b/src/rpc/virnetsocket.c
> > @@ -310,8 +310,8 @@ int virNetSocketNewListenTCP(const char *nodename,
> >      struct addrinfo hints;
> >      int fd = -1;
> >      size_t i;
> > -    bool addrInUse = false;
> > -    bool familyNotSupported = false;
> > +    int socketErrno = 0;
> > +    int bindErrno = 0;
> >      virSocketAddr tmp_addr;
> >  
> >      *retsocks = NULL;
> > @@ -351,7 +351,7 @@ int virNetSocketNewListenTCP(const char *nodename,
> >          if ((fd = socket(runp->ai_family, runp->ai_socktype,
> >                           runp->ai_protocol)) < 0) {
> >              if (errno == EAFNOSUPPORT) {
> > -                familyNotSupported = true;
> > +                socketErrno = errno;
> >                  runp = runp->ai_next;
> >                  continue;
> >              }
> > @@ -386,7 +386,7 @@ int virNetSocketNewListenTCP(const char *nodename,
> >                  virReportSystemError(errno, "%s", _("Unable to bind to port"));
> >                  goto error;
> >              }
> > -            addrInUse = true;
> > +            bindErrno = errno;
> >              VIR_FORCE_CLOSE(fd);
> >              runp = runp->ai_next;
> >              continue;
> > @@ -409,14 +409,14 @@ int virNetSocketNewListenTCP(const char *nodename,
> >          fd = -1;
> >      }
> >  
> > -    if (nsocks == 0 && familyNotSupported) {
> > -        virReportSystemError(EAFNOSUPPORT, "%s", _("Unable to bind to port"));
> > -        goto error;
> > -    }
> > -
> > -    if (nsocks == 0 &&
> > -        addrInUse) {
> > -        virReportSystemError(EADDRINUSE, "%s", _("Unable to bind to port"));
> > +    if (nsocks == 0) {
> > +        if (bindErrno) {
> > +            virReportSystemError(bindErrno, "%s", _("Unable to bind to port"));
> > +        } else if (socketErrno) {
> > +            virReportSystemError(socketErrno, "%s", _("Unable to create socket"));
> > +        } else {
> > +            virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("No addresses to bind to"));
> > +        }
> 
> We usually don't use {} around single line bodies, you can remove all of
> them here.

Oh yes, I always get this wrong since QEMU requires the opposite
to libvirt - always {} no matter what :-)

> 
> >          goto error;
> >      }
> 
> Reviewed-by: Jiri Denemark <jdenemar at redhat.com>

Regards,
Daniel
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