Rename package proctl -> proc

proc/stack.go

@@ -0,0 +1,62 @@
+package proc
+
+import (
+	"debug/gosym"
+	"encoding/binary"
+)
+
+type stackLocation struct {
+	addr uint64
+	file string
+	line int
+	fn   *gosym.Func
+}
+
+// Takes an offset from RSP and returns the address of the
+// instruction the currect function is going to return to.
+func (thread *ThreadContext) ReturnAddress() (uint64, error) {
+	regs, err := thread.Registers()
+	if err != nil {
+		return 0, err
+	}
+	locations, err := thread.dbp.stacktrace(regs.PC(), regs.SP(), 1)
+	if err != nil {
+		return 0, err
+	}
+	return locations[0].addr, nil
+}
+
+type NullAddrError struct{}
+
+func (n NullAddrError) Error() string {
+	return "NULL address"
+}
+
+func (dbp *DebuggedProcess) stacktrace(pc, sp uint64, depth int) ([]stackLocation, error) {
+	var (
+		ret       = pc
+		data      = make([]byte, 8)
+		btoffset  int64
+		locations []stackLocation
+		retaddr   uintptr
+	)
+	for i := int64(0); i < int64(depth); i++ {
+		fde, err := dbp.frameEntries.FDEForPC(ret)
+		if err != nil {
+			return nil, err
+		}
+		btoffset += fde.ReturnAddressOffset(ret)
+		retaddr = uintptr(int64(sp) + btoffset + (i * 8))
+		if retaddr == 0 {
+			return nil, NullAddrError{}
+		}
+		_, err = readMemory(dbp.CurrentThread, retaddr, data)
+		if err != nil {
+			return nil, err
+		}
+		ret = binary.LittleEndian.Uint64(data)
+		f, l, fn := dbp.goSymTable.PCToLine(ret)
+		locations = append(locations, stackLocation{addr: ret, file: f, line: l, fn: fn})
+	}
+	return locations, nil
+}