Initial commit

vendor/github.com/bouk/monkey/replace.go

@@ -0,0 +1,31 @@
+package monkey
+
+import (
+	"reflect"
+	"syscall"
+	"unsafe"
+)
+
+func rawMemoryAccess(p uintptr, length int) []byte {
+	return *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
+		Data: p,
+		Len:  length,
+		Cap:  length,
+	}))
+}
+
+func pageStart(ptr uintptr) uintptr {
+	return ptr & ^(uintptr(syscall.Getpagesize() - 1))
+}
+
+// from is a pointer to the actual function
+// to is a pointer to a go funcvalue
+func replaceFunction(from, to uintptr) (original []byte) {
+	jumpData := jmpToFunctionValue(to)
+	f := rawMemoryAccess(from, len(jumpData))
+	original = make([]byte, len(f))
+	copy(original, f)
+
+	copyToLocation(from, jumpData)
+	return
+}