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, 18 insertions, 0 deletions

diff --git a/sys/amd64/include/sigframe.h b/sys/amd64/include/sigframe.h
index 947743d..98be731 100644
--- a/sys/amd64/include/sigframe.h
+++ b/sys/amd64/include/sigframe.h
@@ -35,6 +35,7 @@
  * Signal frames, arguments passed to application signal handlers.
  */
 #ifdef _KERNEL
+#ifdef COMPAT_43
 struct osigframe {
 	/*
 	 * The first four members may be used by applications.
@@ -70,6 +71,23 @@ struct osigframe {
 	osiginfo_t	sf_siginfo;
 };
 #endif
+#ifdef COMPAT_FREEBSD4
+/* FreeBSD 4.x */
+struct sigframe4 {
+	register_t	sf_signum;
+	register_t	sf_siginfo;	/* code or pointer to sf_si */
+	register_t	sf_ucontext;	/* points to sf_uc */
+	register_t	sf_addr;	/* undocumented 4th arg */
+
+	union {
+		__siginfohandler_t	*sf_action;
+		__sighandler_t		*sf_handler;
+	} sf_ahu;
+	struct ucontext4 sf_uc;		/* = *sf_ucontext */
+	siginfo_t	sf_si;		/* = *sf_siginfo (SA_SIGINFO case) */
+};
+#endif
+#endif
 
 struct sigframe {
 	/*