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size.go
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size.go
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// Copyright 2017 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
package prog
import (
"fmt"
"strings"
)
func (target *Target) generateSize(arg Arg, lenType *LenType) uint64 {
if arg == nil {
// Arg is an optional pointer, set size to 0.
return 0
}
bitSize := lenType.BitSize
if bitSize == 0 {
bitSize = 8
}
switch arg.Type().(type) {
case *VmaType:
a := arg.(*PointerArg)
return a.VmaSize * 8 / bitSize
case *ArrayType:
a := arg.(*GroupArg)
if lenType.BitSize != 0 {
return a.Size() * 8 / bitSize
}
return uint64(len(a.Inner))
default:
return arg.Size() * 8 / bitSize
}
}
func (target *Target) assignSizes(args []Arg, parentsMap map[Arg]Arg) {
// Create a map from field names to args.
argsMap := make(map[string]Arg)
for _, arg := range args {
if IsPad(arg.Type()) {
continue
}
argsMap[arg.Type().FieldName()] = arg
}
// Fill in size arguments.
for _, arg := range args {
if arg = InnerArg(arg); arg == nil {
continue // Pointer to optional len field, no need to fill in value.
}
if typ, ok := arg.Type().(*LenType); ok {
a := arg.(*ConstArg)
buf, ok := argsMap[typ.Buf]
if ok {
a.Val = target.generateSize(InnerArg(buf), typ)
continue
}
if typ.Buf == "parent" {
a.Val = parentsMap[arg].Size()
if typ.BitSize != 0 {
a.Val = a.Val * 8 / typ.BitSize
}
continue
}
sizeAssigned := false
for parent := parentsMap[arg]; parent != nil; parent = parentsMap[parent] {
parentName := parent.Type().Name()
if pos := strings.IndexByte(parentName, '['); pos != -1 {
// For template parents, strip arguments.
parentName = parentName[:pos]
}
if typ.Buf == parentName {
a.Val = parent.Size()
if typ.BitSize != 0 {
a.Val = a.Val * 8 / typ.BitSize
}
sizeAssigned = true
break
}
}
if sizeAssigned {
continue
}
panic(fmt.Sprintf("len field '%v' references non existent field '%v', argsMap: %+v",
typ.FieldName(), typ.Buf, argsMap))
}
}
}
func (target *Target) assignSizesArray(args []Arg) {
parentsMap := make(map[Arg]Arg)
for _, arg := range args {
ForeachSubArg(arg, func(arg Arg, _ *ArgCtx) {
if _, ok := arg.Type().(*StructType); ok {
for _, field := range arg.(*GroupArg).Inner {
parentsMap[InnerArg(field)] = arg
}
}
})
}
target.assignSizes(args, parentsMap)
for _, arg := range args {
ForeachSubArg(arg, func(arg Arg, _ *ArgCtx) {
if _, ok := arg.Type().(*StructType); ok {
target.assignSizes(arg.(*GroupArg).Inner, parentsMap)
}
})
}
}
func (target *Target) assignSizesCall(c *Call) {
target.assignSizesArray(c.Args)
}
func (r *randGen) mutateSize(arg *ConstArg, parent []Arg) bool {
typ := arg.Type().(*LenType)
elemSize := typ.BitSize / 8
if elemSize == 0 {
elemSize = 1
for _, field := range parent {
if typ.Buf != field.Type().FieldName() {
continue
}
if inner := InnerArg(field); inner != nil {
switch targetType := inner.Type().(type) {
case *VmaType:
return false
case *ArrayType:
if targetType.Type.Varlen() {
return false
}
elemSize = targetType.Type.Size()
}
}
break
}
}
if r.oneOf(100) {
arg.Val = r.rand64()
return true
}
if r.bin() {
// Small adjustment to trigger missed size checks.
if arg.Val != 0 && r.bin() {
arg.Val = r.randRangeInt(0, arg.Val-1)
} else {
arg.Val = r.randRangeInt(arg.Val+1, arg.Val+1000)
}
return true
}
// Try to provoke int overflows.
max := ^uint64(0)
if r.oneOf(3) {
max = 1<<32 - 1
if r.oneOf(2) {
max = 1<<16 - 1
if r.oneOf(2) {
max = 1<<8 - 1
}
}
}
n := max / elemSize
delta := uint64(1000 - r.biasedRand(1000, 10))
if elemSize == 1 || r.oneOf(10) {
n -= delta
} else {
n += delta
}
arg.Val = n
return true
}