arch

package
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 Go to latest Published: Apr 30, 2024 License: Apache-2.0, MIT Imports: 20 Imported by: 0

Documentation

Overview

Package arch provides abstractions around architecture-dependent details, such as syscall calling conventions, native types, etc.

Index

Constants

View Source 
const Host = AMD64

Host specifies the host architecture.

View Source 
const StackBottomMagic = ^hostarch.Addr(0) // hostarch.Addr(-1)

StackBottomMagic is the special address callers must past to all stack marshalling operations to cause the src/dst address to be computed based on the current end of the stack.

View Source 
const (
	// SyscallWidth is the width of syscall, sysenter, and int 80 insturctions.
	SyscallWidth = 2
)

System-related constants for x86.

Variables

View Source 
var (
	// TrapInstruction is the x86 trap instruction.
	TrapInstruction = [1]byte{0xcc}

	// CPUIDInstruction is the x86 CPUID instruction.
	CPUIDInstruction = [2]byte{0xf, 0xa2}

	// X86TrapFlag is an exported const for use by other packages.
	X86TrapFlag uint64 = (1 << 8)
)

Functions

This section is empty.

Types

type Arch 

type Arch int

Arch describes an architecture. 

const (
	// AMD64 is the x86-64 architecture.
	AMD64 Arch = iota
	// ARM64 is the aarch64 architecture.
	ARM64
)

func (Arch) String 

func (a Arch) String() string

String implements fmt.Stringer.

type AuxEntry 

type AuxEntry struct {
	Key   uint64
	Value hostarch.Addr
}

An AuxEntry represents an entry in an ELF auxiliary vector.

+stateify savable

type Auxv 

type Auxv []AuxEntry

An Auxv represents an ELF auxiliary vector.

type Context64 

type Context64 struct {
	State
}

Context64 represents an AMD64 context.

+stateify savable

func New 

func New(arch Arch) *Context64

New returns a new architecture context.

func (*Context64) Arch 

func (c *Context64) Arch() Arch

Arch implements Context.Arch.

func (*Context64) FloatingPointData 

func (c *Context64) FloatingPointData() *fpu.State

FloatingPointData returns the state of the floating-point unit.

func (*Context64) Fork 

func (c *Context64) Fork() *Context64

Fork returns an exact copy of this context.

func (*Context64) IP 

func (c *Context64) IP() uintptr

IP returns the current instruction pointer.

func (*Context64) Native 

func (c *Context64) Native(val uintptr) marshal.Marshallable

Native returns the native type for the given val.

func (*Context64) NewMmapLayout 

func (c *Context64) NewMmapLayout(min, max hostarch.Addr, r *limits.LimitSet) (MmapLayout, error)

NewMmapLayout implements Context.NewMmapLayout consistently with Linux.

func (*Context64) PIELoadAddress 

func (c *Context64) PIELoadAddress(l MmapLayout) hostarch.Addr

PIELoadAddress implements Context.PIELoadAddress.

func (*Context64) PtracePeekUser 

func (c *Context64) PtracePeekUser(addr uintptr) (marshal.Marshallable, error)

PtracePeekUser implements Context.PtracePeekUser.

func (*Context64) PtracePokeUser 

func (c *Context64) PtracePokeUser(addr, data uintptr) error

PtracePokeUser implements Context.PtracePokeUser.

func (*Context64) RestartSyscall 

func (c *Context64) RestartSyscall()

RestartSyscall implements Context.RestartSyscall.

func (*Context64) RestartSyscallWithRestartBlock 

func (c *Context64) RestartSyscallWithRestartBlock()

RestartSyscallWithRestartBlock implements Context.RestartSyscallWithRestartBlock.

func (*Context64) Return 

func (c *Context64) Return() uintptr

Return returns the current syscall return value.

func (*Context64) SetIP 

func (c *Context64) SetIP(value uintptr)

SetIP sets the current instruction pointer.

func (*Context64) SetOldRSeqInterruptedIP 

func (c *Context64) SetOldRSeqInterruptedIP(value uintptr)

SetOldRSeqInterruptedIP implements Context.SetOldRSeqInterruptedIP.

func (*Context64) SetReturn 

func (c *Context64) SetReturn(value uintptr)

SetReturn sets the syscall return value.

func (*Context64) SetStack 

func (c *Context64) SetStack(value uintptr)

SetStack sets the current stack pointer.

func (*Context64) SetTLS 

func (c *Context64) SetTLS(value uintptr) bool

SetTLS sets the current TLS pointer. Returns false if value is invalid.

func (*Context64) SignalRestore 

func (c *Context64) SignalRestore(st *Stack, rt bool, featureSet cpuid.FeatureSet) (linux.SignalSet, linux.SignalStack, error)

SignalRestore implements Context.SignalRestore. (Compare to Linux's arch/x86/kernel/signal.c:sys_rt_sigreturn().)

func (*Context64) SignalSetup 

func (c *Context64) SignalSetup(st *Stack, act *linux.SigAction, info *linux.SignalInfo, alt *linux.SignalStack, sigset linux.SignalSet, featureSet cpuid.FeatureSet) error

SignalSetup implements Context.SignalSetup. (Compare to Linux's arch/x86/kernel/signal.c:__setup_rt_frame().)

func (*Context64) Stack 

func (c *Context64) Stack() uintptr

Stack returns the current stack pointer.

func (*Context64) SyscallArgs 

func (c *Context64) SyscallArgs() SyscallArguments

SyscallArgs provides syscall arguments according to the 64-bit convention.

Due to the way addresses are mapped for the sentry this binary *must* be built in 64-bit mode. So we can just assume the syscall numbers that come back match the expected host system call numbers.

func (*Context64) SyscallNo 

func (c *Context64) SyscallNo() uintptr

SyscallNo returns the syscall number according to the 64-bit convention.

func (*Context64) SyscallSaveOrig 

func (c *Context64) SyscallSaveOrig()

SyscallSaveOrig save the value of the register which is clobbered in syscall handler(doSyscall()).

Noop on x86.

func (*Context64) TLS 

func (c *Context64) TLS() uintptr

TLS returns the current TLS pointer.

func (*Context64) Value 

func (c *Context64) Value(val marshal.Marshallable) uintptr

Value returns the generic val for the given native type.

func (*Context64) Width 

func (c *Context64) Width() uint

Width returns the byte width of this architecture.

type MmapDirection 

type MmapDirection int

MmapDirection is a search direction for mmaps. 

const (
	// MmapBottomUp instructs mmap to prefer lower addresses.
	MmapBottomUp MmapDirection = iota

	// MmapTopDown instructs mmap to prefer higher addresses.
	MmapTopDown
)

type MmapLayout 

type MmapLayout struct {
	// MinAddr is the lowest mappable address.
	MinAddr hostarch.Addr

	// MaxAddr is the highest mappable address.
	MaxAddr hostarch.Addr

	// BottomUpBase is the lowest address that may be returned for a
	// MmapBottomUp mmap.
	BottomUpBase hostarch.Addr

	// TopDownBase is the highest address that may be returned for a
	// MmapTopDown mmap.
	TopDownBase hostarch.Addr

	// DefaultDirection is the direction for most non-fixed mmaps in this
	// layout.
	DefaultDirection MmapDirection

	// MaxStackRand is the maximum randomization to apply to stack
	// allocations to maintain a proper gap between the stack and
	// TopDownBase.
	MaxStackRand uint64
}

MmapLayout defines the layout of the user address space for a particular MemoryManager.

Note that "highest address" below is always exclusive.

+stateify savable

func (*MmapLayout) Valid 

func (m *MmapLayout) Valid() bool

Valid returns true if this layout is valid.

type Registers 

type Registers struct {
	linux.PtraceRegs
}

Registers represents the CPU registers for this architecture.

+stateify savable

type SignalContext64 

type SignalContext64 struct {
	R8      uint64
	R9      uint64
	R10     uint64
	R11     uint64
	R12     uint64
	R13     uint64
	R14     uint64
	R15     uint64
	Rdi     uint64
	Rsi     uint64
	Rbp     uint64
	Rbx     uint64
	Rdx     uint64
	Rax     uint64
	Rcx     uint64
	Rsp     uint64
	Rip     uint64
	Eflags  uint64
	Cs      uint16
	Gs      uint16 // always 0 on amd64.
	Fs      uint16 // always 0 on amd64.
	Ss      uint16 // only restored if _UC_STRICT_RESTORE_SS (unsupported).
	Err     uint64
	Trapno  uint64
	Oldmask linux.SignalSet
	Cr2     uint64
	// Pointer to a struct _fpstate.
	Fpstate  uint64
	Reserved [8]uint64
}

SignalContext64 is equivalent to struct sigcontext, the type passed as the second argument to signal handlers set by signal(2).

+marshal

type Stack 

type Stack struct {
	// Our arch info.
	// We use this for automatic Native conversion of hostarch.Addrs during
	// Push() and Pop().
	Arch *Context64

	// The interface used to actually copy user memory.
	IO usermem.IO

	// Our current stack bottom.
	Bottom hostarch.Addr
	// contains filtered or unexported fields
}

Stack is a simple wrapper around a hostarch.IO and an address. Stack implements marshal.CopyContext, and marshallable values can be pushed or popped from the stack through the marshal.Marshallable interface.

Stack is not thread-safe.

func (*Stack) Align 

func (s *Stack) Align(offset int)

Align aligns the stack to the given offset.

func (*Stack) CopyInBytes 

func (s *Stack) CopyInBytes(sentinel hostarch.Addr, b []byte) (int, error)

CopyInBytes implements marshal.CopyContext.CopyInBytes. CopyInBytes computes an appropriate address based on the current end of the stack. Callers must use the sentinel address StackBottomMagic to marshal methods to indicate this.

func (*Stack) CopyOutBytes 

func (s *Stack) CopyOutBytes(sentinel hostarch.Addr, b []byte) (int, error)

CopyOutBytes implements marshal.CopyContext.CopyOutBytes. CopyOutBytes computes an appropriate address based on the current end of the stack. Callers use the sentinel address StackBottomMagic to marshal methods to indicate this.

func (*Stack) CopyScratchBuffer 

func (s *Stack) CopyScratchBuffer(size int) []byte

CopyScratchBuffer implements marshal.CopyContext.CopyScratchBuffer.

func (*Stack) Load 

func (s *Stack) Load(args []string, env []string, aux Auxv) (StackLayout, error)

Load pushes the given args, env and aux vector to the stack using the well-known format for a new executable. It returns the start and end of the argument and environment vectors.

func (*Stack) PushNullTerminatedByteSlice 

func (s *Stack) PushNullTerminatedByteSlice(bs []byte) (int, error)

PushNullTerminatedByteSlice writes bs to the stack, followed by an extra null byte at the end. On error, the contents of the stack and the bottom cursor are undefined.

type StackLayout 

type StackLayout struct {
	// ArgvStart is the beginning of the argument vector.
	ArgvStart hostarch.Addr

	// ArgvEnd is the end of the argument vector.
	ArgvEnd hostarch.Addr

	// EnvvStart is the beginning of the environment vector.
	EnvvStart hostarch.Addr

	// EnvvEnd is the end of the environment vector.
	EnvvEnd hostarch.Addr
}

StackLayout describes the location of the arguments and environment on the stack.

type State 

type State struct {
	// The system registers.
	Regs Registers
	// contains filtered or unexported fields
}

State contains the common architecture bits for X86 (the build tag of this file ensures it's only built on x86).

+stateify savable

func (*State) ClearSingleStep 

func (s *State) ClearSingleStep()

ClearSingleStep enables single stepping.

func (*State) Fork 

func (s *State) Fork() State

Fork creates and returns an identical copy of the state.

func (*State) FullRestore 

func (s *State) FullRestore() bool

FullRestore indicates whether a full restore is required.

func (State) Proto 

func (s State) Proto() *rpb.Registers

Proto returns a protobuf representation of the system registers in State.

func (*State) PtraceGetRegSet 

func (s *State) PtraceGetRegSet(regset uintptr, dst io.Writer, maxlen int, fs cpuid.FeatureSet) (int, error)

PtraceGetRegSet implements Context.PtraceGetRegSet.

func (*State) PtraceGetRegs 

func (s *State) PtraceGetRegs(dst io.Writer) (int, error)

PtraceGetRegs implements Context.PtraceGetRegs.

func (*State) PtraceSetRegSet 

func (s *State) PtraceSetRegSet(regset uintptr, src io.Reader, maxlen int, fs cpuid.FeatureSet) (int, error)

PtraceSetRegSet implements Context.PtraceSetRegSet.

func (*State) PtraceSetRegs 

func (s *State) PtraceSetRegs(src io.Reader) (int, error)

PtraceSetRegs implements Context.PtraceSetRegs.

func (*State) RegisterMap 

func (s *State) RegisterMap() (map[string]uintptr, error)

RegisterMap returns a map of all registers.

func (*State) SetSingleStep 

func (s *State) SetSingleStep()

SetSingleStep enables single stepping.

func (*State) SingleStep 

func (s *State) SingleStep() bool

SingleStep implements Context.SingleStep.

func (*State) StateData 

func (s *State) StateData() *State

StateData implements Context.StateData.

type SyscallArgument 

type SyscallArgument struct {
	// Prefer to use accessor methods instead of 'Value' directly.
	Value uintptr
}

SyscallArgument is an argument supplied to a syscall implementation. The methods used to access the arguments are named after the ***C type name*** and they convert to the closest Go type available. For example, Int() refers to a 32-bit signed integer argument represented in Go as an int32.

Using the accessor methods guarantees that the conversion between types is correct, taking into account size and signedness (i.e., zero-extension vs signed-extension).

func (SyscallArgument) Int 

func (a SyscallArgument) Int() int32

Int returns the int32 representation of a 32-bit signed integer argument.

func (SyscallArgument) Int64 

func (a SyscallArgument) Int64() int64

Int64 returns the int64 representation of a 64-bit signed integer argument.

func (SyscallArgument) ModeT 

func (a SyscallArgument) ModeT() uint

ModeT returns the int representation of a mode_t argument.

func (SyscallArgument) Pointer 

func (a SyscallArgument) Pointer() hostarch.Addr

Pointer returns the hostarch.Addr representation of a pointer argument.

func (SyscallArgument) SizeT 

func (a SyscallArgument) SizeT() uint

SizeT returns the uint representation of a size_t argument.

func (SyscallArgument) Uint 

func (a SyscallArgument) Uint() uint32

Uint returns the uint32 representation of a 32-bit unsigned integer argument.

func (SyscallArgument) Uint64 

func (a SyscallArgument) Uint64() uint64

Uint64 returns the uint64 representation of a 64-bit unsigned integer argument.

type SyscallArguments 

type SyscallArguments [6]SyscallArgument

SyscallArguments represents the set of arguments passed to a syscall.

type UContext64 

type UContext64 struct {
	Flags    uint64
	Link     uint64
	Stack    linux.SignalStack
	MContext SignalContext64
	Sigset   linux.SignalSet
}

UContext64 is equivalent to ucontext_t on 64-bit x86.

+marshal

Source Files

View all Source files

Directories

Path Synopsis
Package fpu provides basic floating point helpers.
 Package fpu provides basic floating point helpers.

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