From 8de1a307ee09500eb639b66c733d648254ccef12 Mon Sep 17 00:00:00 2001
From: aarzilli <alessandro.arzilli@gmail.com>
Date: Fri, 7 Aug 2015 13:23:18 +0200
Subject: [PATCH] Fix: track recurseLevel in readArray/readSlice

This fix helps avoid infinite recursion.
---
 _fixtures/testvariables2.go | 13 +++++++++++++
 proc/variables.go           | 16 ++++++++--------
 proc/variables_test.go      |  9 +++++++++
 3 files changed, 30 insertions(+), 8 deletions(-)
 create mode 100644 _fixtures/testvariables2.go

diff --git a/_fixtures/testvariables2.go b/_fixtures/testvariables2.go
new file mode 100644
index 00000000..b3816d47
--- /dev/null
+++ b/_fixtures/testvariables2.go
@@ -0,0 +1,13 @@
+package main
+
+import "runtime"
+
+type a struct {
+	aas []a
+}
+
+func main() {
+	var aas = []a{{nil}}
+	aas[0].aas = aas
+	runtime.Breakpoint()
+}
diff --git a/proc/variables.go b/proc/variables.go
index 9045ec53..4cf87ab3 100644
--- a/proc/variables.go
+++ b/proc/variables.go
@@ -522,7 +522,7 @@ func (thread *Thread) extractValueInternal(instructions []byte, addr int64, typ
 		case t.StructName == "string":
 			return thread.readString(ptraddress)
 		case strings.HasPrefix(t.StructName, "[]"):
-			return thread.readSlice(ptraddress, t)
+			return thread.readSlice(ptraddress, t, recurseLevel)
 		default:
 			// Recursively call extractValue to grab
 			// the value of all the members of the struct.
@@ -548,7 +548,7 @@ func (thread *Thread) extractValueInternal(instructions []byte, addr int64, typ
 			return "{...}", nil
 		}
 	case *dwarf.ArrayType:
-		return thread.readArray(ptraddress, t)
+		return thread.readArray(ptraddress, t, recurseLevel)
 	case *dwarf.ComplexType:
 		return thread.readComplex(ptraddress, t.ByteSize)
 	case *dwarf.IntType:
@@ -601,7 +601,7 @@ func (thread *Thread) readString(addr uintptr) (string, error) {
 	return *(*string)(unsafe.Pointer(&val)), nil
 }
 
-func (thread *Thread) readSlice(addr uintptr, t *dwarf.StructType) (string, error) {
+func (thread *Thread) readSlice(addr uintptr, t *dwarf.StructType, recurseLevel int) (string, error) {
 	var sliceLen, sliceCap int64
 	var arrayAddr uintptr
 	var arrayType dwarf.Type
@@ -644,7 +644,7 @@ func (thread *Thread) readSlice(addr uintptr, t *dwarf.StructType) (string, erro
 	if _, ok := arrayType.(*dwarf.PtrType); ok {
 		stride = int64(thread.dbp.arch.PtrSize())
 	}
-	vals, err := thread.readArrayValues(arrayAddr, sliceLen, stride, arrayType)
+	vals, err := thread.readArrayValues(arrayAddr, sliceLen, stride, arrayType, recurseLevel)
 	if err != nil {
 		return "", err
 	}
@@ -652,9 +652,9 @@ func (thread *Thread) readSlice(addr uintptr, t *dwarf.StructType) (string, erro
 	return fmt.Sprintf("[]%s len: %d, cap: %d, [%s]", arrayType, sliceLen, sliceCap, strings.Join(vals, ",")), nil
 }
 
-func (thread *Thread) readArray(addr uintptr, t *dwarf.ArrayType) (string, error) {
+func (thread *Thread) readArray(addr uintptr, t *dwarf.ArrayType, recurseLevel int) (string, error) {
 	if t.Count > 0 {
-		vals, err := thread.readArrayValues(addr, t.Count, t.ByteSize/t.Count, t.Type)
+		vals, err := thread.readArrayValues(addr, t.Count, t.ByteSize/t.Count, t.Type, recurseLevel)
 		if err != nil {
 			return "", err
 		}
@@ -664,7 +664,7 @@ func (thread *Thread) readArray(addr uintptr, t *dwarf.ArrayType) (string, error
 	return fmt.Sprintf("%s []", t), nil
 }
 
-func (thread *Thread) readArrayValues(addr uintptr, count int64, stride int64, t dwarf.Type) ([]string, error) {
+func (thread *Thread) readArrayValues(addr uintptr, count int64, stride int64, t dwarf.Type, recurseLevel int) ([]string, error) {
 	vals := make([]string, 0)
 
 	for i := int64(0); i < count; i++ {
@@ -674,7 +674,7 @@ func (thread *Thread) readArrayValues(addr uintptr, count int64, stride int64, t
 			break
 		}
 
-		val, err := thread.extractValue(nil, int64(addr+uintptr(i*stride)), t, false)
+		val, err := thread.extractValueInternal(nil, int64(addr+uintptr(i*stride)), t, false, recurseLevel+1)
 		if err != nil {
 			return nil, err
 		}
diff --git a/proc/variables_test.go b/proc/variables_test.go
index ba82de93..f5785330 100644
--- a/proc/variables_test.go
+++ b/proc/variables_test.go
@@ -216,3 +216,12 @@ func TestLocalVariables(t *testing.T) {
 		}
 	})
 }
+
+func TestRecursiveStructure(t *testing.T) {
+	withTestProcess("testvariables2", t, func(p *Process, fixture protest.Fixture) {
+		assertNoError(p.Continue(), t, "Continue()")
+		v, err := p.EvalVariable("aas")
+		assertNoError(err, t, "EvalVariable()")
+		t.Logf("v: %v\n", v)
+	})
+}