package runtime

const (
	_SS_DISABLE  = 2
	_NSIG        = 65
	_SIG_BLOCK   = 0
	_SIG_UNBLOCK = 1
	_SIG_SETMASK = 2
)

// It's hard to tease out exactly how big a Sigset is, but
// rt_sigprocmask crashes if we get it wrong, so if binaries
// are running, this is right.
type sigset [2]uint32

var sigset_all = sigset{^uint32(0), ^uint32(0)}

//go:nosplit
//go:nowritebarrierrec

//go:noescape
func lwp_create(param *lwpparams) int32

//go:noescape
func sigaltstack(new, old *stackt)

//go:noescape
func sigaction(sig uint32, new, old *sigactiont)

//go:noescape
func sigprocmask(how int32, new, old *sigset)

//go:noescape
func setitimer(mode int32, new, old *itimerval)

//go:noescape
func sysctl(mib *uint32, miblen uint32, out *byte, size *uintptr, dst *byte, ndst uintptr) int32

	callWithVarargs("dummy arg", 3.1415);

	if (sigemptyset(&mask) < 0) {
		die("sigemptyset");
	}
	if (sigaddset(&mask, SIGSEGV) < 0) {
		die("sigaddset");
	}
	i = sigprocmask(SIG_UNBLOCK, &mask, NULL);
	if (i != 0) {
		fprintf(stderr, "sigprocmask: %s\n", strerror(i));
		exit(EXIT_FAILURE);
	}

	// Don't try this at home.
	longjmp(jmp, signo);

	// We should never get here.
	abort();
}

		tls_base:   unsafe.Pointer(&mp.tls[0]),
		tls_size:   unsafe.Sizeof(mp.tls),
	}

	var oset sigset
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
	ret := retryOnEAGAIN(func() int32 {
		errno := thr_new(&param, int32(unsafe.Sizeof(param)))
		// thr_new returns negative errno
		return -errno
	})
	sigprocmask(_SIG_SETMASK, &oset, nil)
	if ret != 0 {

	sigset_t mask;
	int i;

	if (sigemptyset(&mask) < 0) {
		die("sigemptyset");
	}
	if (sigaddset(&mask, SIGSEGV) < 0) {
		die("sigaddset");
	}
	i = sigprocmask(SIG_UNBLOCK, &mask, NULL);
	if (i != 0) {
		fprintf(stderr, "sigprocmask: %s\n", strerror(i));
		exit(EXIT_FAILURE);
	}

	// Don't try this at home.
	longjmp(jmp, signo);

	// We should never get here.
	abort();
}

	// Finally, create the thread. It starts at mstart_stub, which does some low-level
	// setup and then calls mstart.
	var oset sigset
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
	err = retryOnEAGAIN(func() int32 {
		return pthread_create(&attr, abi.FuncPCABI0(mstart_stub), unsafe.Pointer(mp))
	})
	sigprocmask(_SIG_SETMASK, &oset, nil)
	if err != 0 {
		writeErrStr(failthreadcreate)
		exit(1)
	}
}

	uc.uc_sigmask = sigset_all

	var oset sigset
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)

	lwp_mcontext_init(&uc.uc_mcontext, stk, mp, mp.g0, abi.FuncPCABI0(netbsdMstart))

	ret := retryOnEAGAIN(func() int32 {
		errno := lwp_create(unsafe.Pointer(&uc), _LWP_DETACHED, unsafe.Pointer(&mp.procid))
		// lwp_create returns negative errno
		return -errno
	})
	sigprocmask(_SIG_SETMASK, &oset, nil)
	if ret != 0 {

	// Disable signals during create, so that the new thread starts
	// with signals disabled. It will enable them in minit.
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
	ret = retryOnEAGAIN(func() int32 {
		return pthread_create(&tid, &attr, abi.FuncPCABI0(tstart_sysvicall), unsafe.Pointer(mp))
	})
	sigprocmask(_SIG_SETMASK, &oset, nil)
	if ret != 0 {

var Closeonexec = closeonexec

func sigismember(mask *sigset, i int) bool {
	clear := *mask
	sigdelset(&clear, i)
	return clear != *mask
}

func Sigisblocked(i int) bool {
	var sigmask sigset
	sigprocmask(_SIG_SETMASK, nil, &sigmask)
	return sigismember(&sigmask, i)
}

type M = m

var waitForSigusr1 struct {
	rdpipe int32
	wrpipe int32
	mID    int64
}

// the stack is safe to reclaim.
//
//go:noescape
func exitThread(wait *atomic.Uint32)

//go:noescape
func obsdsigprocmask(how int32, new sigset) sigset

//go:nosplit
//go:nowritebarrierrec
func sigprocmask(how int32, new, old *sigset) {
	n := sigset(0)
	if new != nil {
		n = *new
	}
	r := obsdsigprocmask(how, n)
	if old != nil {
		*old = r
	}
}

func pipe2(flags int32) (r, w int32, errno int32)