zebra: kernel_socket: fix 64bit MacOS X alignment

In OS X 10.7 zebra crashed on invalid execution address.

sockaddr padding in *_msghdr is observed to be 4 bytes in 64bit OS X.

The ROUNDUP macro assumed alignment on sizeof(long) which
allocates 8 bytes on 64bit systems, 4 bytes on 32bit systems
which is true for BSD generally.

Test for Apple and use sizeof(int) which allocates 4 bytes on 32 & 64bit
systems.

Tested on 64bit OS X 10.7, FreeBSD 9.0 amd64 & i386 (32bit)
using gcc & clang

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

diff --git a/zebra/kernel_socket.c b/zebra/kernel_socket.c
index b7061e762151e7d0e0985cbc2c99333d1155b5df..ecc6e7905d0f925e4295f2c20c4f2e28d021bb93 100644 (file)
--- a/zebra/kernel_socket.c
+++ b/zebra/kernel_socket.c
@@ -48,9 +48,15 @@ extern struct zebra_t zebrad;
  * XXX: why is ROUNDUP(0) sizeof(long)?  0 is an illegal sockaddr
  * length anyway (< sizeof (struct sockaddr)), so this shouldn't
  * matter.
+ * On OS X, both 32, 64bit syatems align on 4 byte boundary
  */
+#ifdef __APPLE__
+#define ROUNDUP(a) \
+  ((a) > 0 ? (1 + (((a) - 1) | (sizeof(int) - 1))) : sizeof(int))
+#else
 #define ROUNDUP(a) \
   ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
+#endif
 
 /*
  * Given a pointer (sockaddr or void *), return the number of bytes