Use struct __ucontext in prototypes and associated functions instead of

ucontext_t.  Forward declare struct __ucontext in <sys/signal.h> and
remove reliance on <sys/ucontext.h> being included.

While I'm here, also hide osigcontext types from userland; suggested
by bde.

Namespace pollution noticed by: Kevin Day <toasty@shell.dragondata.com>

sys/alpha/alpha/machdep.c

@@ -128,6 +128,7 @@
 #include <vm/vm_pager.h>
 #include <sys/user.h>
 #include <sys/ptrace.h>
+#include <sys/ucontext.h>
 #include <machine/clock.h>
 #include <machine/md_var.h>
 #include <machine/reg.h>
@@ -1506,7 +1507,7 @@ osigreturn(struct thread *td,
 int
 sigreturn(struct thread *td,
 	struct sigreturn_args /* {
-		ucontext_t *sigcntxp;
+		const struct __ucontext *sigcntxp;
 	} */ *uap)
 {
 	ucontext_t uc, *ucp;

sys/alpha/include/sigframe.h

@@ -31,15 +31,17 @@
 #ifndef _MACHINE_SIGFRAME_H_
 #define _MACHINE_SIGFRAME_H_ 1
 
+#ifdef _KERNEL
 struct osigframe {
 	struct osigcontext	sf_sc;
 	osiginfo_t		sf_si;
 };
+#endif
 
 struct sigframe {
-	unsigned long	__spare__;
-	ucontext_t	sf_uc;
-	siginfo_t	sf_si;
+	unsigned long		__spare__;
+	struct __ucontext	sf_uc;
+	siginfo_t		sf_si;
 };
 
 #endif /* _MACHINE_SIGFRAME_H_ */

sys/alpha/include/signal.h

@@ -41,6 +41,10 @@ typedef long	sig_atomic_t;
  */
 #define	MINSIGSTKSZ	(1024 * 4)
 
+/*
+ * Only the kernel should need these old type definitions.
+ */
+#ifdef _KERNEL
 /*
  * Information pushed on stack when a signal is delivered.
  * This is used by the kernel to restore state following
@@ -70,6 +74,7 @@ struct  osigcontext {
 	unsigned long sc_traparg_a2;	/* a2 argument to trap at exception */
 	long	sc_xxx2[3];		/* sc_fp_trap_pc, sc_fp_trigger_sum, sc_fp_trigger_inst */
 };
+#endif
 
 /*
  * The sequence of the fields should match those in

sys/amd64/amd64/genassym.c

@@ -50,6 +50,7 @@
 #include <sys/mutex.h>
 #include <sys/socket.h>
 #include <sys/resourcevar.h>
+#include <sys/ucontext.h>
 #include <sys/user.h>
 #include <machine/bootinfo.h>
 #include <machine/tss.h>

sys/amd64/amd64/machdep.c

@@ -72,6 +72,7 @@
 #include <sys/msgbuf.h>
 #include <sys/sysent.h>
 #include <sys/sysctl.h>
+#include <sys/ucontext.h>
 #include <sys/vmmeter.h>
 #include <sys/bus.h>
 #include <sys/eventhandler.h>
@@ -706,7 +707,7 @@ int
 sigreturn(td, uap)
 	struct thread *td;
 	struct sigreturn_args /* {
-		ucontext_t *sigcntxp;
+		const __ucontext *sigcntxp;
 	} */ *uap;
 {
 	struct proc *p = td->td_proc;

sys/amd64/include/sigframe.h

@@ -34,7 +34,7 @@
 /*
  * Signal frames, arguments passed to application signal handlers.
  */
-
+#ifdef _KERNEL
 struct osigframe {
 	/*
 	 * The first four members may be used by applications.
@@ -69,6 +69,7 @@ struct osigframe {
 	/* In the SA_SIGINFO case, sf_arg2 points here. */
 	osiginfo_t	sf_siginfo;
 };
+#endif
 
 struct sigframe {
 	/*

sys/amd64/include/signal.h

@@ -53,6 +53,10 @@ typedef int sig_atomic_t;
 
 #include <machine/trap.h>	/* codes for SIGILL, SIGFPE */
 
+/*
+ * Only the kernel should need these old type definitions.
+ */
+#ifdef _KERNEL
 /*
  * Information pushed on stack when a signal is delivered.
  * This is used by the kernel to restore state following
@@ -85,6 +89,7 @@ struct osigcontext {
 	int	sc_trapno;
 	int	sc_err;
 };
+#endif
 
 /*
  * The sequence of the fields/registers in struct sigcontext should match

sys/i386/i386/genassym.c

@@ -50,6 +50,7 @@
 #include <sys/mutex.h>
 #include <sys/socket.h>
 #include <sys/resourcevar.h>
+#include <sys/ucontext.h>
 #include <sys/user.h>
 #include <machine/bootinfo.h>
 #include <machine/tss.h>

sys/i386/i386/machdep.c

@@ -72,6 +72,7 @@
 #include <sys/msgbuf.h>
 #include <sys/sysent.h>
 #include <sys/sysctl.h>
+#include <sys/ucontext.h>
 #include <sys/vmmeter.h>
 #include <sys/bus.h>
 #include <sys/eventhandler.h>
@@ -706,7 +707,7 @@ int
 sigreturn(td, uap)
 	struct thread *td;
 	struct sigreturn_args /* {
-		ucontext_t *sigcntxp;
+		const __ucontext *sigcntxp;
 	} */ *uap;
 {
 	struct proc *p = td->td_proc;

sys/i386/include/sigframe.h

@@ -34,7 +34,7 @@
 /*
  * Signal frames, arguments passed to application signal handlers.
  */
-
+#ifdef _KERNEL
 struct osigframe {
 	/*
 	 * The first four members may be used by applications.
@@ -69,6 +69,7 @@ struct osigframe {
 	/* In the SA_SIGINFO case, sf_arg2 points here. */
 	osiginfo_t	sf_siginfo;
 };
+#endif
 
 struct sigframe {
 	/*

sys/i386/include/signal.h

@@ -53,6 +53,10 @@ typedef int sig_atomic_t;
 
 #include <machine/trap.h>	/* codes for SIGILL, SIGFPE */
 
+/*
+ * Only the kernel should need these old type definitions.
+ */
+#ifdef _KERNEL
 /*
  * Information pushed on stack when a signal is delivered.
  * This is used by the kernel to restore state following
@@ -85,6 +89,7 @@ struct osigcontext {
 	int	sc_trapno;
 	int	sc_err;
 };
+#endif
 
 /*
  * The sequence of the fields/registers in struct sigcontext should match

sys/sys/_sigset.h

@@ -247,8 +247,11 @@ typedef struct sigaltstack {
 #define	SS_DISABLE	0x0004	/* disable taking signals on alternate stack */
 #define	SIGSTKSZ	(MINSIGSTKSZ + 32768)	/* recommended stack size */
 
-/* Have enough typedefs for this now.  XXX */
-#include <sys/ucontext.h>
+/*
+ * Forward declaration for __ucontext so that sigreturn can use it
+ * without having to include <ucontext.h>.
+ */
+struct __ucontext;
 
 /*
  * 4.3 compatibility:

sys/sys/signal.h

@@ -247,8 +247,11 @@ typedef struct sigaltstack {
 #define	SS_DISABLE	0x0004	/* disable taking signals on alternate stack */
 #define	SIGSTKSZ	(MINSIGSTKSZ + 32768)	/* recommended stack size */
 
-/* Have enough typedefs for this now.  XXX */
-#include <sys/ucontext.h>
+/*
+ * Forward declaration for __ucontext so that sigreturn can use it
+ * without having to include <ucontext.h>.
+ */
+struct __ucontext;
 
 /*
  * 4.3 compatibility:

sys/sys/signalvar.h

@@ -60,6 +60,7 @@ struct sigacts {
 	sigset_t ps_usertramp;		/* SunOS compat; libc sigtramp XXX */
 };
 
+#ifdef _KERNEL
 /*
  * Compatibility.
  */
@@ -80,6 +81,7 @@ struct osigaction {
 };
 
 typedef void __osiginfohandler_t __P((int, osiginfo_t *, void *));
+#endif /* _KERNEL */
 
 /* additional signal action values, used only temporarily/internally */
 #define	SIG_CATCH	((__sighandler_t *)2)