// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Emulation of the Unix signal SIGSEGV.
//
// On iOS, Go tests and apps under development are run by lldb.
// The debugger uses a task-level exception handler to intercept signals.
// Despite having a 'handle' mechanism like gdb, lldb will not allow a
// SIGSEGV to pass to the running program. For Go, this means we cannot

	log  *profBuf // profile events written here

	// extra holds extra stacks accumulated in addNonGo
	// corresponding to profiling signals arriving on
	// non-Go-created threads. Those stacks are written
	// to log the next time a normal Go thread gets the
	// signal handler.
	// Assuming the stacks are 2 words each (we don't get
	// a full traceback from those threads), plus one word

	return e == EINTR || e == EMFILE || e.Timeout()
}

func (e Errno) Timeout() bool {
	return e == EAGAIN || e == ETIMEDOUT
}

// A Signal is a number describing a process signal.
// It implements the [os.Signal] interface.
type Signal uint8

const (
	SIGNONE Signal = iota
	SIGHUP
	SIGINT
	SIGQUIT
	SIGILL
	SIGTRAP
	SIGABRT
	SIGBUS
	SIGFPE
	SIGKILL
	SIGUSR1
	SIGSEGV
	SIGUSR2

	MOVD	R1, R4

	// Store g on gsignal's stack, so if we receive a signal
	// during VDSO code we can find the g.
	// If we don't have a signal stack, we won't receive signal,
	// so don't bother saving g.
	// When using cgo, we already saved g on TLS, also don't save
	// g here.
	// Also don't save g if we are already on the signal stack.
	// We won't get a nested signal.
	MOVBZ	runtime·iscgo(SB), R22
	CMP	R22, $0
	BNE	nosaveg

	// with its controlling terminal shall cause the process group
	// to be sent a SIGTTOU signal. If the calling thread is
	// blocking SIGTTOU signals or the process is ignoring SIGTTOU
	// signals, the process shall be allowed to perform the
	// operation, and no signal is sent."
	//  -https://pubs.opengroup.org/onlinepubs/9699919799/functions/tcsetpgrp.html
	//

	SIGIO      = Signal(0x16)
	SIGIOT     = Signal(0x6)
	SIGJVM1    = Signal(0x27)
	SIGJVM2    = Signal(0x28)
	SIGKILL    = Signal(0x9)
	SIGLOST    = Signal(0x25)
	SIGLWP     = Signal(0x21)
	SIGPIPE    = Signal(0xd)
	SIGPOLL    = Signal(0x16)
	SIGPROF    = Signal(0x1d)
	SIGPWR     = Signal(0x13)
	SIGQUIT    = Signal(0x3)
	SIGSEGV    = Signal(0xb)
	SIGSTOP    = Signal(0x17)
	SIGSYS     = Signal(0xc)

}

func (w WaitStatus) Signaled() bool { return w&mask != stopped && w&mask != 0 }

func (w WaitStatus) Signal() Signal {
	sig := Signal(w & mask)
	if sig == stopped || sig == 0 {
		return -1
	}
	return sig
}

func (w WaitStatus) CoreDump() bool { return w.Signaled() && w&core != 0 }

func (w WaitStatus) Stopped() bool { return w&mask == stopped && Signal(w>>shift) != SIGSTOP }

)

const (
	// More invented values for signals
	SIGHUP  = Signal(0x1)
	SIGINT  = Signal(0x2)
	SIGQUIT = Signal(0x3)
	SIGILL  = Signal(0x4)
	SIGTRAP = Signal(0x5)
	SIGABRT = Signal(0x6)
	SIGBUS  = Signal(0x7)
	SIGFPE  = Signal(0x8)
	SIGKILL = Signal(0x9)
	SIGSEGV = Signal(0xb)
	SIGPIPE = Signal(0xd)
	SIGALRM = Signal(0xe)
	SIGTERM = Signal(0xf)
)

var signals = [...]string{
	1:  "hangup",
	2:  "interrupt",

		return errENOENT
	}
	return e
}

// A Signal is a number describing a process signal.
// It implements the [os.Signal] interface.
type Signal int

func (s Signal) Signal() {}

func (s Signal) String() string {
	if 0 <= s && int(s) < len(signals) {
		str := signals[s]
		if str != "" {
			return str
		}
	}
	return "signal " + itoa.Itoa(int(s))
}

	SIGTSTP   = syscall.Signal(0x14)
	SIGTTIN   = syscall.Signal(0x15)
	SIGTTOU   = syscall.Signal(0x16)
	SIGURG    = syscall.Signal(0x17)
	SIGUSR1   = syscall.Signal(0xa)
	SIGUSR2   = syscall.Signal(0xc)
	SIGVTALRM = syscall.Signal(0x1a)
	SIGWINCH  = syscall.Signal(0x1c)
	SIGXCPU   = syscall.Signal(0x18)
	SIGXFSZ   = syscall.Signal(0x19)
)

// Error table
var errorList = [...]struct {
	num  syscall.Errno