Implemented running executables in memory

src/memfile/Exec_linux.go

@@ -0,0 +1,47 @@
+//go:build linux
+
+package memfile
+
+import (
+	"os"
+	"strconv"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// Exec executes an in-memory file.
+func Exec(file *os.File) error {
+	empty, err := syscall.BytePtrFromString("")
+
+	if err != nil {
+		return err
+	}
+
+	argv := []string{"/proc/self/fd/" + strconv.Itoa(int(file.Fd()))}
+	argvp, err := syscall.SlicePtrFromStrings(argv)
+
+	if err != nil {
+		return err
+	}
+
+	envv := os.Environ()
+	envvp, err := syscall.SlicePtrFromStrings(envv)
+
+	if err != nil {
+		return err
+	}
+
+	_, _, errno := syscall.Syscall6(
+		unix.SYS_EXECVEAT,
+		uintptr(file.Fd()),
+		uintptr(unsafe.Pointer(empty)),
+		uintptr(unsafe.Pointer(&argvp[0])),
+		uintptr(unsafe.Pointer(&envvp[0])),
+		uintptr(unix.AT_EMPTY_PATH),
+		0,
+	)
+
+	return errno
+}