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, 28 insertions, 0 deletions

diff --git a/sys/i386/include/ucontext.h b/sys/i386/include/ucontext.h
index d02959c..af9b4fd 100644
--- a/sys/i386/include/ucontext.h
+++ b/sys/i386/include/ucontext.h
@@ -73,6 +73,34 @@ typedef struct __mcontext {
 } mcontext_t;
 
 #ifdef _KERNEL
+#ifdef COMPAT_FREEBSD4
+/* For 4.x binaries */
+struct mcontext4 {
+	int	mc_onstack;		/* XXX - sigcontext compat. */
+	int	mc_gs;
+	int	mc_fs;
+	int	mc_es;
+	int	mc_ds;
+	int	mc_edi;
+	int	mc_esi;
+	int	mc_ebp;
+	int	mc_isp;
+	int	mc_ebx;
+	int	mc_edx;
+	int	mc_ecx;
+	int	mc_eax;
+	int	mc_trapno;
+	int	mc_err;
+	int	mc_eip;
+	int	mc_cs;
+	int	mc_eflags;
+	int	mc_esp;			/* machine state */
+	int	mc_ss;
+	int	mc_fpregs[28];		/* env87 + fpacc87 + u_long */
+	int	__spare__[17];
+};
+#endif
+
 struct thread;
 
 void	get_mcontext(struct thread *td, mcontext_t *mcp);