Split 4.x and 5.x signal handling so that we can keep 4.x signal

handling clean and functional as 5.x evolves.  This allows some of the
nasty bandaids in the 5.x codepaths to be unwound.

Encapsulate 4.x signal handling under COMPAT_FREEBSD4 (there is an
anti-foot-shooting measure in place, 5.x folks need this for a while) and
finish encapsulating the older stuff under COMPAT_43.  Since the ancient
stuff is required on alpha (longjmp(3) passes a 'struct osigcontext *'
to the current sigreturn(2), instead of the 'ucontext_t *' that sigreturn
is supposed to take), add a compile time check to prevent foot shooting
there too.  Add uniform COMPAT_43 stubs for ia64/sparc64/powerpc.

Tested on: i386, alpha, ia64.  Compiled on sparc64 (a few days ago).
Approved by: re

1 files changed, 7 insertions, 1 deletions

diff --git a/sys/i386/include/md_var.h b/sys/i386/include/md_var.h
index f449c04..9fa3968 100644
--- a/sys/i386/include/md_var.h
+++ b/sys/i386/include/md_var.h
@@ -56,7 +56,13 @@ extern	int	need_post_dma_flush;
 #endif
 extern	void	(*ovbcopy_vector)(const void *from, void *to, size_t len);
 extern	char	sigcode[];
-extern	int	szsigcode, szosigcode;
+extern	int	szsigcode;
+#ifdef COMPAT_FREEBSD4
+extern	int	szfreebsd4_sigcode;
+#endif
+#ifdef COMPAT_43
+extern	int	szosigcode;
+#endif
 
 typedef void alias_for_inthand_t(u_int cs, u_int ef, u_int esp, u_int ss);
 struct	thread;