sysmsg

type ArchState struct {
	// contains filtered or unexported fields
}

type ContextState uint32

type Msg struct {
	// The next batch of fields is used to call the syshandler stub
	// function. A system call can be replaced with a function call. When
	// a function call is executed, it can't change the current process
	// stack, so it needs to save stack and instruction registers, switch
	// on its syshandler stack and call the jmp instruction to the syshandler
	// address.
	//
	// Self is a pointer to itself in a process address space.
	Self uint64
	// RetAddr is a return address from the syshandler function.
	RetAddr uint64
	// Syshandler is an address of the syshandler function.
	Syshandler uint64
	// SyshandlerStack is an address of  the thread syshandler stack.
	SyshandlerStack uint64
	// AppStack is a value of the stack register before calling the syshandler
	// function.
	AppStack uint64

	// State indicates to the sentry what the sysmsg thread is doing at a given
	// moment.
	State ThreadState
	// Context is a pointer to the ThreadContext struct that the current sysmsg
	// thread is processing.
	Context uint64

	// FaultJump is the size of a faulted instruction.
	FaultJump int32
	// Err is the error value with which the {sig|sys}handler crashes the stub
	// thread (see sysmsg.h:__panic).
	Err int32
	// Line is the code line on which the {sig|sys}handler crashed the stub thread
	// (see sysmsg.h:panic).
	Line int32
	// Debug is a variable to use to get visibility into the stub from the sentry.
	Debug uint64
	// ThreadID is the ID of the sysmsg thread.
	ThreadID uint32
	// contains filtered or unexported fields
}

type ThreadContext struct {
	// FPState is a region of memory where:
	//   - syshandler saves FPU state to using xsave/fxsave
	//   - sighandler copies FPU state to from ucontext->uc_mcontext.fpregs
	// Note that xsave requires this region of memory to be 64 byte aligned;
	// therefore allocations of ThreadContext must be too.
	FPState [MaxFPStateLen]byte
	// FPStateChanged is set to true when the stub thread needs to restore FPState
	// because the sentry changed it.
	FPStateChanged uint64
	// Regs is the context's GP register set. The {sig|sys}handler will save and
	// restore the user app's registers here.
	Regs linux.PtraceRegs

	// SignalInfo is the siginfo struct.
	SignalInfo linux.SignalInfo
	// Signo is the signal that the stub is requesting the sentry to handle.
	Signo int64
	// State indicates the reason why the context has exited back to the sentry.
	State ContextState
	// Interrupt is set to indicate that this context has been interrupted.
	Interrupt uint32
	// ThreadID is the ID of the sysmsg thread that's currently working on the
	// context.
	ThreadID uint32
	// LastThreadID is the ID of the previous sysmsg thread that ran the context
	// (not the one currently working on it). This field is used by sysmsg threads
	// to detect whether fpstate may have changed since the last time they ran a
	// context.
	LastThreadID uint32
	// SentryFastPath is used to indicate to the stub thread that the sentry
	// goroutine used for this thread context is busy-polling for a response
	// instead of using FUTEX_WAIT.
	SentryFastPath uint32
	// Acked is used by sysmsg threads to signal to the sentry that this context
	// has been picked up from the context queue and is actively being worked on.
	Acked uint32
	// TLS is a pointer to a thread local storage.
	// It is is only populated on ARM64.
	TLS uint64
	// Debug is a variable to use to get visibility into the stub from the sentry.
	Debug uint64
}

type ThreadState uint32