On 04/03/2013 09:06 AM, Daniel P. Berrange wrote: > From: "Daniel P. Berrange" <[email protected]> > > To avoid > > virportallocatortest.c: In function 'bind': > virportallocatortest.c:34:33: warning: cast increases required alignment of > target type [-Wcast-align] > struct sockaddr_in *saddr = (struct sockaddr_in *)addr; > ^ > > Signed-off-by: Daniel P. Berrange <[email protected]> > --- > tests/virportallocatortest.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/tests/virportallocatortest.c b/tests/virportallocatortest.c > index 9931e11..1935602 100644 > --- a/tests/virportallocatortest.c > +++ b/tests/virportallocatortest.c > @@ -31,12 +31,14 @@ int bind(int sockfd ATTRIBUTE_UNUSED, > const struct sockaddr *addr, > socklen_t addrlen ATTRIBUTE_UNUSED) > { > - struct sockaddr_in *saddr = (struct sockaddr_in *)addr; > + struct sockaddr_in saddr;
Hmm. POSIX requires that apps use sockaddr_storage to guarantee
alignment before downcasting to struct sockaddr_in or further down to
struct sockaddr. But since we are providing a replacement bind(), and
POSIX doesn't give us any way to specify that 'struct sockaddr' in our
signature should have been aligned as struct sockaddr_storage by any
sane caller, we're stuck playing realignment games, or else using a pragma.
>
> - if (saddr->sin_port == htons(5900) ||
> - saddr->sin_port == htons(5904) ||
> - saddr->sin_port == htons(5905) ||
> - saddr->sin_port == htons(5906)) {
> + memcpy(&saddr, addr, sizeof(saddr));
Since this is just test code, performance doesn't matter, and using
memcpy() for the realignment game makes sense.
ACK.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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