msyscall

README

Go Memfd syscall library

This provides the low level syscalls and constants for working with memfd_create and related Linux syscalls.

Documentation

Overview

msyscall is a package for the raw syscall handling for memfd_create and related syscalls. Used by github.com/justincormack/go-memfd

Index

• Constants
• func FcntlCloexec(fd uintptr, flag int) (err error)
• func FcntlSeals(fd uintptr) (seals int, err error)
• func FcntlSetSeals(fd uintptr, seals int) (err error)
• func MemfdCreate(name string, flags uint) (fd uintptr, err error)

Constants

const (
	MFD_CLOEXEC       uint = 1
	MFD_ALLOW_SEALING uint = 2

	F_ADD_SEALS int = (f_LINUX_SPECIFIC_BASE + 9)
	F_GET_SEALS int = (f_LINUX_SPECIFIC_BASE + 10)

	F_SEAL_SEAL   int = 0x0001
	F_SEAL_SHRINK int = 0x0002
	F_SEAL_GROW   int = 0x0004
	F_SEAL_WRITE  int = 0x0008
)

Linux kernel constants

const (
	// SYS_FCNTL is the fcntl syscall to use for this architecture
	SYS_FCNTL = syscall.SYS_FCNTL
	// SYS_MEMFD_CREATE is the syscall number for this architecture
	SYS_MEMFD_CREATE = 319
)

Functions

func FcntlCloexec

func FcntlCloexec(fd uintptr, flag int) (err error)

FcntlCloexec clears the cloexec flag (0 arg) or sets it (1), useful just before we exec another process.

func FcntlSeals

func FcntlSeals(fd uintptr) (seals int, err error)

FcntlSeals calls the raw fcntl syscall to get the current seals it will return EINVAL if the file does not support sealing

func FcntlSetSeals

func FcntlSetSeals(fd uintptr, seals int) (err error)

FcntlSetSeals calls the raw fcntl syscall to set the specified seals it will return EINVAL if the file does not support sealing, or an error if already sealed.

func MemfdCreate

func MemfdCreate(name string, flags uint) (fd uintptr, err error)

MemfdCreate exposes the raw memfd_create syscall which returns a file descriptor