Merge pull request #113 from xairy/parent-parent

Make it possible to specify length of parent of parent

11 files changed, 120 insertions, 32 deletions

diff --git a/csource/csource.go b/csource/csource.go
index 08ccae03a..183c787ab 100644
--- a/csource/csource.go
+++ b/csource/csource.go
@@ -205,7 +205,7 @@ loop:
 				if bfOff == 0 && bfLen == 0 {
 					fmt.Fprintf(w, "\tNONFAILING(*(uint%v_t*)0x%x = (uint%v_t)0x%x);\n", size*8, addr, size*8, arg)
 				} else {
-					fmt.Fprintf(w, "\tNONFAILING(STORE_BY_BITMASK(uint%v_t, %v, %v, %v, %v));\n", size*8, addr, arg, bfOff, bfLen)
+					fmt.Fprintf(w, "\tNONFAILING(STORE_BY_BITMASK(uint%v_t, 0x%x, 0x%x, %v, %v));\n", size*8, addr, arg, bfOff, bfLen)
 				}
 			case prog.ExecArgResult:
 				fmt.Fprintf(w, "\tNONFAILING(*(uint%v_t*)0x%x = %v);\n", size*8, addr, resultRef())
diff --git a/prog/analysis.go b/prog/analysis.go
index a4f399f98..81c17c9ee 100644
--- a/prog/analysis.go
+++ b/prog/analysis.go
@@ -174,18 +174,14 @@ func generateSize(arg *Arg, lenType *sys.LenType) *Arg {
 	}
 }
 
-func assignSizes(args []*Arg) {
+func assignSizes(args []*Arg, parentsMap map[*Arg]*Arg) {
 	// Create a map of args and calculate size of the whole struct.
 	argsMap := make(map[string]*Arg)
-	var parentSize uintptr
 	for _, arg := range args {
-		if arg.Type.BitfieldLength() == 0 || arg.Type.BitfieldLast() {
-			parentSize += arg.Size()
-		}
 		if sys.IsPad(arg.Type) {
 			continue
 		}
-		argsMap[arg.Type.Name()] = arg
+		argsMap[arg.Type.FieldName()] = arg
 	}
 
 	// Fill in size arguments.
@@ -194,32 +190,60 @@ func assignSizes(args []*Arg) {
 			continue // Pointer to optional len field, no need to fill in value.
 		}
 		if typ, ok := arg.Type.(*sys.LenType); ok {
+			buf, ok := argsMap[typ.Buf]
+			if ok {
+				*arg = *generateSize(buf.InnerArg(), typ)
+				continue
+			}
+
 			if typ.Buf == "parent" {
-				arg.Val = parentSize
+				arg.Val = parentsMap[arg].Size()
 				if typ.ByteSize != 0 {
 					arg.Val /= typ.ByteSize
 				}
 				continue
 			}
 
-			buf, ok := argsMap[typ.Buf]
-			if !ok {
-				panic(fmt.Sprintf("len field '%v' references non existent field '%v', argsMap: %+v",
-					typ.Name(), typ.Buf, argsMap))
+			sizeAssigned := false
+			for parent := parentsMap[arg]; parent != nil; parent = parentsMap[parent] {
+				if typ.Buf == parent.Type.Name() {
+					arg.Val = parent.Size()
+					if typ.ByteSize != 0 {
+						arg.Val /= typ.ByteSize
+					}
+					sizeAssigned = true
+					break
+				}
+			}
+			if sizeAssigned {
+				continue
 			}
 
-			*arg = *generateSize(buf.InnerArg(), typ)
+			panic(fmt.Sprintf("len field '%v' references non existent field '%v', argsMap: %+v",
+				typ.FieldName(), typ.Buf, argsMap))
 		}
 	}
 }
 
-func assignSizesCall(c *Call) {
-	assignSizes(c.Args)
-	foreachArg(c, func(arg, base *Arg, parent *[]*Arg) {
+func assignSizesArray(args []*Arg) {
+	parentsMap := make(map[*Arg]*Arg)
+	foreachArgArray(&args, nil, func(arg, base *Arg, _ *[]*Arg) {
 		if _, ok := arg.Type.(*sys.StructType); ok {
-			assignSizes(arg.Inner)
+			for _, field := range arg.Inner {
+				parentsMap[field.InnerArg()] = arg
+			}
 		}
 	})
+	assignSizes(args, parentsMap)
+	foreachArgArray(&args, nil, func(arg, base *Arg, _ *[]*Arg) {
+		if _, ok := arg.Type.(*sys.StructType); ok {
+			assignSizes(arg.Inner, parentsMap)
+		}
+	})
+}
+
+func assignSizesCall(c *Call) {
+	assignSizesArray(c.Args)
 }
 
 func sanitizeCall(c *Call) {
diff --git a/prog/encoding.go b/prog/encoding.go
index 8c7c1674a..274e94a2d 100644
--- a/prog/encoding.go
+++ b/prog/encoding.go
@@ -108,7 +108,7 @@ func (a *Arg) serialize(buf io.Writer, vars map[*Arg]int, varSeq *int) {
 		}
 		buf.Write([]byte{delims[1]})
 	case ArgUnion:
-		fmt.Fprintf(buf, "@%v=", a.OptionType.Name())
+		fmt.Fprintf(buf, "@%v=", a.OptionType.FieldName())
 		a.Option.serialize(buf, vars, varSeq)
 	default:
 		panic("unknown arg kind")
@@ -318,7 +318,7 @@ func parseArg(typ sys.Type, p *parser, vars map[string]*Arg) (*Arg, error) {
 		p.Parse('=')
 		var optType sys.Type
 		for _, t2 := range t1.Options {
-			if name == t2.Name() {
+			if name == t2.FieldName() {
 				optType = t2
 				break
 			}
diff --git a/prog/mutation.go b/prog/mutation.go
index 2136c86f8..9841d31ca 100644
--- a/prog/mutation.go
+++ b/prog/mutation.go
@@ -184,8 +184,12 @@ func (p *Prog) Mutate(rs rand.Source, ncalls int, ct *ChoiceTable, corpus []*Pro
 						}
 					case *sys.UnionType:
 						optType := a.Options[r.Intn(len(a.Options))]
-						for optType.Name() == arg.OptionType.Name() {
+						maxIters := 1000
+						for i := 0; optType.FieldName() == arg.OptionType.FieldName(); i++ {
 							optType = a.Options[r.Intn(len(a.Options))]
+							if i >= maxIters {
+								panic(fmt.Sprintf("couldn't generate a different union option after %v iterations, type: %+v", maxIters, a))
+							}
 						}
 						p.removeArg(c, arg.Option)
 						opt, calls := r.generateArg(s, optType)
@@ -303,7 +307,7 @@ func Minimize(p0 *Prog, callIndex0 int, pred func(*Prog, int) bool, crash bool)
 
 	var rec func(p *Prog, call *Call, arg *Arg, path string) bool
 	rec = func(p *Prog, call *Call, arg *Arg, path string) bool {
-		path += fmt.Sprintf("-%v", arg.Type.Name())
+		path += fmt.Sprintf("-%v", arg.Type.FieldName())
 		switch typ := arg.Type.(type) {
 		case *sys.StructType:
 			for _, innerArg := range arg.Inner {
@@ -438,7 +442,7 @@ func (p *Prog) TrimAfter(idx int) {
 }
 
 func mutationArgs(c *Call) (args, bases []*Arg) {
-	foreachArg(c, func(arg, base *Arg, parent *[]*Arg) {
+	foreachArg(c, func(arg, base *Arg, _ *[]*Arg) {
 		switch typ := arg.Type.(type) {
 		case *sys.StructType:
 			if isSpecialStruct(typ) == nil {
diff --git a/prog/rand.go b/prog/rand.go
index 4645db811..4a7bbe08d 100644
--- a/prog/rand.go
+++ b/prog/rand.go
@@ -557,6 +557,7 @@ func (r *randGen) generateParticularCall(s *state, meta *sys.Call) (calls []*Cal
 		Ret:  returnArg(meta.Ret),
 	}
 	c.Args, calls = r.generateArgs(s, meta.Args)
+	assignSizesCall(c)
 	calls = append(calls, c)
 	for _, c1 := range calls {
 		sanitizeCall(c1)
@@ -601,8 +602,6 @@ func (r *randGen) generateArgs(s *state, types []sys.Type) ([]*Arg, []*Call) {
 		calls = append(calls, calls1...)
 	}
 
-	assignSizes(args)
-
 	return args, calls
 }
 
diff --git a/prog/size_test.go b/prog/size_test.go
index 0b7e5fb98..f6e4ab17c 100644
--- a/prog/size_test.go
+++ b/prog/size_test.go
@@ -72,7 +72,7 @@ func TestAssignSize(t *testing.T) {
 		},
 		{
 			"syz_test$length8(&(0x7f000001f000)={0x00, {0xff, 0x0, 0x00, [0xff, 0xff, 0xff]}, [{0xff, 0x0, 0x00, [0xff, 0xff, 0xff]}], 0x00, 0x0, [0xff, 0xff]})",
-			"syz_test$length8(&(0x7f000001f000)={0x32, {0xff, 0x1, 0x10, [0xff, 0xff, 0xff]}, [{0xff, 0x1, 0x10, [0xff, 0xff, 0xff]}], 0x10, 0x1, [0xff, 0xff]})",
+			"syz_test$length8(&(0x7f000001f000)={0x38, {0xff, 0x1, 0x10, [0xff, 0xff, 0xff]}, [{0xff, 0x1, 0x10, [0xff, 0xff, 0xff]}], 0x10, 0x1, [0xff, 0xff]})",
 		},
 		{
 			"syz_test$length9(&(0x7f000001f000)={&(0x7f0000000000/0x5000)=nil, (0x0000)})",
@@ -118,6 +118,10 @@ func TestAssignSize(t *testing.T) {
 			"syz_test$length19(&(0x7f0000000000)={{0x42, 0x42, 0x42, 0x42, 0x42, 0x42, 0x42, 0xff}, 0xff, 0xff, 0xff})",
 			"syz_test$length19(&(0x7f0000000000)={{0x42, 0x42, 0x42, 0x42, 0x42, 0x42, 0x42, 0x14}, 0x14, 0x14, 0x5})",
 		},
+		{
+			"syz_test$length20(&(0x7f0000000000)={{{0xff, 0xff, 0xff, 0xff}, 0xff, 0xff, 0xff}, 0xff, 0xff})",
+			"syz_test$length20(&(0x7f0000000000)={{{0x4, 0x4, 0x7, 0x9}, 0x7, 0x7, 0x9}, 0x9, 0x9})",
+		},
 	}
 
 	for i, test := range tests {
diff --git a/prog/validation.go b/prog/validation.go
index 5eea42e65..f03ec10b8 100644
--- a/prog/validation.go
+++ b/prog/validation.go
@@ -59,6 +59,9 @@ func (c *Call) validate(ctx *validCtx) error {
 		if arg.Type.Name() != typ.Name() {
 			return fmt.Errorf("syscall %v: type name mismatch: %v vs %v", c.Meta.Name, arg.Type.Name(), typ.Name())
 		}
+		if arg.Type.FieldName() != typ.FieldName() {
+			return fmt.Errorf("syscall %v: field name mismatch: %v vs %v", c.Meta.Name, arg.Type.FieldName(), typ.FieldName())
+		}
 		if arg.Type.Dir() == sys.DirOut {
 			if (arg.Val != 0 && arg.Val != arg.Type.Default()) || arg.AddrPage != 0 || arg.AddrOffset != 0 {
 				// We generate output len arguments, which makes sense
diff --git a/sys/README.md b/sys/README.md
index 2e5f07ec1..b5b497bc6 100644
--- a/sys/README.md
+++ b/sys/README.md
@@ -133,6 +133,36 @@ accept(fd sock, ...) sock
 listen(fd sock, backlog int32)
 ```
 
+### Length
+
+You can specify length of a particular field in struct or a named argument by using `len` and `bytesize` types, for example:
+```
+write(fd fd, buf buffer[in], count len[buf]) len[buf]
+
+sock_fprog {
+	len	len[filter, int16]
+	filter	ptr[in, array[sock_filter]]
+}
+```
+
+If `len`'s argument is a pointer (or a `buffer`), then the length of the pointee argument is used.
+
+To denote the length of a field in N-byte words use `bytesizeN`, possible values for N are 1, 2, 4 and 8.
+
+To denote the length of the parent struct, you can use `len[parent, int8]`.
+To denote the length of the higher level parent when structs are embedded into one another, you can specify the type name of the particular parent:
+```
+struct s1 {
+    f0      len[s2]  # length of s2
+}
+
+struct s2 {
+    f0      s1
+    f1      array[int32]
+}
+
+```
+
 ### Proc
 
 The `proc` type can be used to denote per process integers.
diff --git a/sys/decl.go b/sys/decl.go
index a495ffd4a..3c98d1038 100644
--- a/sys/decl.go
+++ b/sys/decl.go
@@ -29,6 +29,7 @@ const (
 
 type Type interface {
 	Name() string
+	FieldName() string
 	Dir() Dir
 	Optional() bool
 	Default() uintptr
@@ -49,6 +50,7 @@ func IsPad(t Type) bool {
 
 type TypeCommon struct {
 	TypeName   string
+	FldName    string // for struct fields and named args
 	ArgDir     Dir
 	IsOptional bool
 }
@@ -57,6 +59,10 @@ func (t *TypeCommon) Name() string {
 	return t.TypeName
 }
 
+func (t *TypeCommon) FieldName() string {
+	return t.FldName
+}
+
 func (t *TypeCommon) Optional() bool {
 	return t.IsOptional
 }
diff --git a/sys/test.txt b/sys/test.txt
index e36af549d..0ce7ec819 100644
--- a/sys/test.txt
+++ b/sys/test.txt
@@ -186,6 +186,8 @@ syz_test$length17(a0 ptr[in, syz_length_bytesize2_struct])
 syz_test$length18(a0 ptr[in, syz_length_bytesize3_struct])
 syz_test$length19(a0 ptr[in, syz_length_bf_struct])
 
+syz_test$length20(a0 ptr[in, syz_length_parent2_struct])
+
 syz_length_flags = 0, 1
 
 syz_length_int_struct {
@@ -299,6 +301,26 @@ syz_length_bf_struct {
 	f3	bytesize4[f0, int8]
 }
 
+syz_length_parent2_struct_inner_inner {
+	f1	len[parent, int8]
+	f2	len[syz_length_parent2_struct_inner_inner, int8]
+	f3	len[syz_length_parent2_struct_inner, int8]
+	f4	len[syz_length_parent2_struct, int8]
+}
+
+syz_length_parent2_struct_inner {
+	f0	syz_length_parent2_struct_inner_inner
+	f1	len[parent, int8]
+	f2	len[syz_length_parent2_struct_inner, int8]
+	f3	len[syz_length_parent2_struct, int8]
+}
+
+syz_length_parent2_struct {
+	f0	syz_length_parent2_struct_inner
+	f1	len[parent, int8]
+	f2	len[syz_length_parent2_struct, int8]
+}
+
 # Big endian
 
 syz_test$end0(a0 ptr[in, syz_end_int_struct])
diff --git a/sysgen/sysgen.go b/sysgen/sysgen.go
index 867561ad7..6906c7697 100644
--- a/sysgen/sysgen.go
+++ b/sysgen/sysgen.go
@@ -265,10 +265,6 @@ func generateStructEntry(str Struct, key structKey, out io.Writer) {
 	if str.IsUnion {
 		typ = "UnionType"
 	}
-	name := key.field
-	if name == "" {
-		name = key.name
-	}
 	packed := ""
 	if str.Packed {
 		packed = ", packed: true"
@@ -281,8 +277,8 @@ func generateStructEntry(str Struct, key structKey, out io.Writer) {
 	if str.Align != 0 {
 		align = fmt.Sprintf(", align: %v", str.Align)
 	}
-	fmt.Fprintf(out, "\"%v\": &%v{TypeCommon: TypeCommon{TypeName: \"%v\", ArgDir: %v, IsOptional: %v} %v %v %v},\n",
-		key, typ, name, fmtDir(key.dir), false, packed, align, varlen)
+	fmt.Fprintf(out, "\"%v\": &%v{TypeCommon: TypeCommon{TypeName: \"%v\", FldName: \"%v\", ArgDir: %v, IsOptional: %v} %v %v %v},\n",
+		key, typ, key.name, key.field, fmtDir(key.dir), false, packed, align, varlen)
 }
 
 func generateStructFields(str Struct, key structKey, desc *Description, consts map[string]uint64, out io.Writer) {
@@ -379,7 +375,7 @@ func generateArg(
 		}
 	}
 	common := func() string {
-		return fmt.Sprintf("TypeCommon: TypeCommon{TypeName: %v, ArgDir: %v, IsOptional: %v}", name, fmtDir(dir), opt)
+		return fmt.Sprintf("TypeCommon: TypeCommon{TypeName: \"%v\", FldName: %v, ArgDir: %v, IsOptional: %v}", typ, name, fmtDir(dir), opt)
 	}
 	intCommon := func(typeSize uint64, bigEndian bool, bitfieldLen uint64) string {
 		// BitfieldOff and BitfieldLst will be filled in in initAlign().