Adding upstream version 6.1.22-dfsg.upstream/6.1.22-dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2181 insertions, 0 deletions

diff --git a/src/VBox/Runtime/common/fuzz/fuzz.cpp b/src/VBox/Runtime/common/fuzz/fuzz.cpp
new file mode 100644
index 00000000..579b792d
--- /dev/null
+++ b/src/VBox/Runtime/common/fuzz/fuzz.cpp
@@ -0,0 +1,2181 @@
+/* $Id: fuzz.cpp $ */
+/** @file
+ * IPRT - Fuzzing framework API, core.
+ */
+
+/*
+ * Copyright (C) 2018-2020 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#include <iprt/fuzz.h>
+#include "internal/iprt.h"
+
+#include <iprt/asm.h>
+#include <iprt/assert.h>
+#include <iprt/avl.h>
+#include <iprt/critsect.h>
+#include <iprt/ctype.h>
+#include <iprt/dir.h>
+#include <iprt/err.h>
+#include <iprt/file.h>
+#include <iprt/list.h>
+#include <iprt/md5.h>
+#include <iprt/mem.h>
+#include <iprt/path.h>
+#include <iprt/rand.h>
+#include <iprt/semaphore.h>
+#include <iprt/string.h>
+#include <iprt/time.h>
+#include <iprt/vfs.h>
+
+
+#define RTFUZZCTX_MAGIC UINT32_C(0xdeadc0de) /** @todo */
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+/** Pointer to the internal fuzzer state. */
+typedef struct RTFUZZCTXINT *PRTFUZZCTXINT;
+/** Pointer to a fuzzed mutation. */
+typedef struct RTFUZZMUTATION *PRTFUZZMUTATION;
+/** Pointer to a fuzzed mutation pointer. */
+typedef PRTFUZZMUTATION *PPRTFUZZMUTATION;
+/** Pointer to a const mutation. */
+typedef const struct RTFUZZMUTATION *PCRTFUZZMUTATION;
+
+
+/**
+ * Mutator class.
+ */
+typedef enum RTFUZZMUTATORCLASS
+{
+    /** Invalid class, do not use. */
+    RTFUZZMUTATORCLASS_INVALID = 0,
+    /** Mutator operates on single bits. */
+    RTFUZZMUTATORCLASS_BITS,
+    /** Mutator operates on bytes (single or multiple). */
+    RTFUZZMUTATORCLASS_BYTES,
+    /** Mutator interpretes data as integers and operates on them. */
+    RTFUZZMUTATORCLASS_INTEGERS,
+    /** Mutator uses multiple mutations to create new mutations. */
+    RTFUZZMUTATORCLASS_MUTATORS,
+    /** 32bit hack. */
+    RTFUZZMUTATORCLASS_32BIT_HACK = 0x7fffffff
+} RTFUZZMUTATORCLASS;
+
+
+/**
+ * Mutator preparation callback.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The fuzzer context instance.
+ * @param   offStart            Where the mutation should start.
+ * @param   pMutationParent     The parent mutation to start working from.
+ * @param   ppMutation          Where to store the created mutation on success.
+ */
+typedef DECLCALLBACK(int) FNRTFUZZCTXMUTATORPREP(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                 PPRTFUZZMUTATION ppMutation);
+/** Pointer to a mutator preparation callback. */
+typedef FNRTFUZZCTXMUTATORPREP *PFNRTFUZZCTXMUTATORPREP;
+
+
+/**
+ * Mutator execution callback.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The fuzzer context instance.
+ * @param   pMutation           The mutation to work on.
+ * @param   pvMutation          Mutation dependent data.
+ * @param   pbBuf               The buffer to work on.
+ * @param   cbBuf               Size of the remaining buffer.
+ */
+typedef DECLCALLBACK(int) FNRTFUZZCTXMUTATOREXEC(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                 uint8_t *pbBuf, size_t cbBuf);
+/** Pointer to a mutator execution callback. */
+typedef FNRTFUZZCTXMUTATOREXEC *PFNRTFUZZCTXMUTATOREXEC;
+
+
+/**
+ * Mutator export callback.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The fuzzer context instance.
+ * @param   pMutation           The mutation to work on.
+ * @param   pvMutation          Mutation dependent data.
+ * @param   pfnExport           The export callback.
+ * @param   pvUser              Opaque user data to pass to the export callback.
+ */
+typedef DECLCALLBACK(int) FNRTFUZZCTXMUTATOREXPORT(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                   PFNRTFUZZCTXEXPORT pfnExport, void *pvUser);
+/** Pointer to a mutator export callback. */
+typedef FNRTFUZZCTXMUTATOREXPORT *PFNRTFUZZCTXMUTATOREXPORT;
+
+
+/**
+ * Mutator import callback.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The fuzzer context instance.
+ * @param   pMutation           The mutation to work on.
+ * @param   pvMutation          Mutation dependent data.
+ * @param   pfnExport           The import callback.
+ * @param   pvUser              Opaque user data to pass to the import callback.
+ */
+typedef DECLCALLBACK(int) FNRTFUZZCTXMUTATORIMPORT(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, void *pvMutation,
+                                                   PFNRTFUZZCTXIMPORT pfnImport, void *pvUser);
+/** Pointer to a mutator import callback. */
+typedef FNRTFUZZCTXMUTATORIMPORT *PFNRTFUZZCTXMUTATORIMPORT;
+
+
+/**
+ * A fuzzing mutator descriptor.
+ */
+typedef struct RTFUZZMUTATOR
+{
+    /** Id of the mutator. */
+    const char                  *pszId;
+    /** Mutator description. */
+    const char                  *pszDesc;
+    /** Mutator index. */
+    uint32_t                    uMutator;
+    /** Mutator class. */
+    RTFUZZMUTATORCLASS          enmClass;
+    /** Additional flags for the mutator, controlling the behavior. */
+    uint64_t                    fFlags;
+    /** The preparation callback. */
+    PFNRTFUZZCTXMUTATORPREP     pfnPrep;
+    /** The execution callback. */
+    PFNRTFUZZCTXMUTATOREXEC     pfnExec;
+    /** The export callback. */
+    PFNRTFUZZCTXMUTATOREXPORT   pfnExport;
+    /** The import callback. */
+    PFNRTFUZZCTXMUTATORIMPORT   pfnImport;
+} RTFUZZMUTATOR;
+/** Pointer to a fuzzing mutator descriptor. */
+typedef RTFUZZMUTATOR *PRTFUZZMUTATOR;
+/** Pointer to a const fuzzing mutator descriptor. */
+typedef const RTFUZZMUTATOR *PCRTFUZZMUTATOR;
+
+/** The special corpus mutator. */
+#define RTFUZZMUTATOR_ID_CORPUS             UINT32_C(0xffffffff)
+
+/** Mutator always works from the end of the buffer (no starting offset generation). */
+#define RTFUZZMUTATOR_F_END_OF_BUF          RT_BIT_64(0)
+/** Default flags. */
+#define RTFUZZMUTATOR_F_DEFAULT             (0)
+
+
+/**
+ * A fuzzed mutation.
+ */
+typedef struct RTFUZZMUTATION
+{
+    /** The AVL tree core. */
+    AVLU64NODECORE              Core;
+    /** The list node if the mutation has the mutated
+     * data allocated. */
+    RTLISTNODE                  NdAlloc;
+    /** Magic identifying this structure. */
+    uint32_t                    u32Magic;
+    /** Reference counter. */
+    volatile uint32_t           cRefs;
+    /** The fuzzer this mutation belongs to. */
+    PRTFUZZCTXINT               pFuzzer;
+    /** Parent mutation (no reference is held), NULL means root or original data. */
+    PRTFUZZMUTATION             pMutationParent;
+    /** Mutation level. */
+    uint32_t                    iLvl;
+    /** The mutator causing this mutation, NULL if original input data. */
+    PCRTFUZZMUTATOR             pMutator;
+    /** Byte offset where the mutation starts. */
+    uint64_t                    offMutation;
+    /** Size of the generated input data in bytes after the mutation was applied. */
+    size_t                      cbInput;
+    /** Size of the mutation dependent data. */
+    size_t                      cbMutation;
+    /** Size allocated for the input. */
+    size_t                      cbAlloc;
+    /** Pointer to the input data if created. */
+    void                        *pvInput;
+    /** Flag whether the mutation is contained in the tree of the context. */
+    bool                        fInTree;
+    /** Flag whether the mutation input data is cached. */
+    bool                        fCached;
+    /** Mutation dependent data, variable in size. */
+    uint8_t                     abMutation[1];
+} RTFUZZMUTATION;
+
+
+/**
+ * A fuzzing input seed.
+ */
+typedef struct RTFUZZINPUTINT
+{
+    /** Magic identifying this structure. */
+    uint32_t                    u32Magic;
+    /** Reference counter. */
+    volatile uint32_t           cRefs;
+    /** The fuzzer this input belongs to. */
+    PRTFUZZCTXINT               pFuzzer;
+    /** The top mutation to work from (reference held). */
+    PRTFUZZMUTATION             pMutationTop;
+    /** Fuzzer context type dependent data. */
+    union
+    {
+        /** Blob data. */
+        struct
+        {
+            /** Pointer to the input data if created. */
+            void                *pvInput;
+        } Blob;
+        /** Stream state. */
+        struct
+        {
+            /** Number of bytes seen so far. */
+            size_t              cbSeen;
+        } Stream;
+    } u;
+} RTFUZZINPUTINT;
+/** Pointer to the internal input state. */
+typedef RTFUZZINPUTINT *PRTFUZZINPUTINT;
+/** Pointer to an internal input state pointer. */
+typedef PRTFUZZINPUTINT *PPRTFUZZINPUTINT;
+
+
+/**
+ * The fuzzer state.
+ */
+typedef struct RTFUZZCTXINT
+{
+    /** Magic value for identification. */
+    uint32_t                    u32Magic;
+    /** Reference counter. */
+    volatile uint32_t           cRefs;
+    /** The random number generator. */
+    RTRAND                      hRand;
+    /** Fuzzing context type. */
+    RTFUZZCTXTYPE               enmType;
+    /** Semaphore protecting the mutations tree. */
+    RTSEMRW                     hSemRwMutations;
+    /** The AVL tree for indexing the mutations (keyed by counter). */
+    AVLU64TREE                  TreeMutations;
+    /** Number of inputs currently in the tree. */
+    volatile uint64_t           cMutations;
+    /** The maximum size of one input seed to generate. */
+    size_t                      cbInputMax;
+    /** Behavioral flags. */
+    uint32_t                    fFlagsBehavioral;
+    /** Number of enabled mutators. */
+    uint32_t                    cMutators;
+    /** Pointer to the mutator descriptors. */
+    PRTFUZZMUTATOR              paMutators;
+    /** Maximum amount of bytes of mutated inputs to cache. */
+    size_t                      cbMutationsAllocMax;
+    /** Current amount of bytes of cached mutated inputs. */
+    size_t                      cbMutationsAlloc;
+    /** List of mutators having data allocated currently. */
+    RTLISTANCHOR                LstMutationsAlloc;
+    /** Critical section protecting the allocation list. */
+    RTCRITSECT                  CritSectAlloc;
+    /** Total number of bytes of memory currently allocated in total for this context. */
+    volatile size_t             cbMemTotal;
+} RTFUZZCTXINT;
+
+
+/**
+ * The fuzzer state to be exported - all members are stored in little endian form.
+ */
+typedef struct RTFUZZCTXSTATE
+{
+    /** Magic value for identification. */
+    uint32_t                    u32Magic;
+    /** Context type. */
+    uint32_t                    uCtxType;
+    /** Size of the PRNG state following in bytes. */
+    uint32_t                    cbPrng;
+    /** Number of mutator descriptors following. */
+    uint32_t                    cMutators;
+    /** Number of mutation descriptors following. */
+    uint32_t                    cMutations;
+    /** Behavioral flags. */
+    uint32_t                    fFlagsBehavioral;
+    /** Maximum input size to generate. */
+    uint64_t                    cbInputMax;
+} RTFUZZCTXSTATE;
+/** Pointer to a fuzzing context state. */
+typedef RTFUZZCTXSTATE *PRTFUZZCTXSTATE;
+
+/** BLOB context type. */
+#define RTFUZZCTX_STATE_TYPE_BLOB         UINT32_C(0)
+/** Stream context type. */
+#define RTFUZZCTX_STATE_TYPE_STREAM       UINT32_C(1)
+
+
+/**
+ * The fuzzer mutation state to be exported - all members are stored in little endian form.
+ */
+typedef struct RTFUZZMUTATIONSTATE
+{
+    /** The mutation identifier. */
+    uint64_t                    u64Id;
+    /** The mutation identifier of the parent, 0 for no parent. */
+    uint64_t                    u64IdParent;
+    /** The byte offset where the mutation starts. */
+    uint64_t                    u64OffMutation;
+    /** Size of input data after mutation was applied. */
+    uint64_t                    cbInput;
+    /** Size of mutation dependent data following. */
+    uint64_t                    cbMutation;
+    /** The mutator ID. */
+    uint32_t                    u32IdMutator;
+    /** The mutation level. */
+    uint32_t                    iLvl;
+    /** Magic value for identification. */
+    uint32_t                    u32Magic;
+} RTFUZZMUTATIONSTATE;
+
+
+/**
+ * Fuzzing context memory header.
+ */
+typedef struct RTFUZZMEMHDR
+{
+    /** Size of the memory area following. */
+    size_t                      cb;
+#if HC_ARCH_BITS == 32
+    /** Some padding. */
+    uint32_t                    uPadding0;
+#elif HC_ARCH_BITS == 64
+    /** Some padding. */
+    uint64_t                    uPadding0;
+#else
+# error "Port me"
+#endif
+} RTFUZZMEMHDR;
+/** Pointer to a memory header. */
+typedef RTFUZZMEMHDR *PRTFUZZMEMHDR;
+
+
+/**
+ * Fuzzing context export AVL arguments.
+ */
+typedef struct RTFUZZEXPORTARGS
+{
+    /** Pointer to the export callback. */
+    PFNRTFUZZCTXEXPORT pfnExport;
+    /** Opaque user data to pass to the callback. */
+    void               *pvUser;
+} RTFUZZEXPORTARGS;
+/** Pointer to the export arguments. */
+typedef RTFUZZEXPORTARGS *PRTFUZZEXPORTARGS;
+/** Pointer to the constant export arguments. */
+typedef const RTFUZZEXPORTARGS *PCRTFUZZEXPORTARGS;
+
+
+/**
+ * Integer replacing mutator additional data.
+ */
+typedef struct RTFUZZMUTATORINTEGER
+{
+    /** The integer class. */
+    uint8_t                     uIntClass;
+    /** Flag whether to do a byte swap. */
+    bool                        fByteSwap;
+    /** The index into the class specific array. */
+    uint16_t                    idxInt;
+} RTFUZZMUTATORINTEGER;
+/** Pointer to additional integer replacing mutator data. */
+typedef RTFUZZMUTATORINTEGER *PRTFUZZMUTATORINTEGER;
+/** Pointer to constant additional integer replacing mutator data. */
+typedef const RTFUZZMUTATORINTEGER *PCRTFUZZMUTATORINTEGER;
+
+
+/*********************************************************************************************************************************
+*   Internal Functions                                                                                                           *
+*********************************************************************************************************************************/
+static DECLCALLBACK(int) rtFuzzCtxMutatorBitFlipPrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                     PPRTFUZZMUTATION ppMutation);
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteReplacePrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                         PPRTFUZZMUTATION ppMutation);
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteInsertPrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                        PPRTFUZZMUTATION ppMutation);
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteSequenceInsertAppendPrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                                      PPRTFUZZMUTATION ppMutation);
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteDeletePrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                        PPRTFUZZMUTATION ppMutation);
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteSequenceDeletePrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                                PPRTFUZZMUTATION ppMutation);
+static DECLCALLBACK(int) rtFuzzCtxMutatorIntegerReplacePrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                            PPRTFUZZMUTATION ppMutation);
+static DECLCALLBACK(int) rtFuzzCtxMutatorCrossoverPrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                       PPRTFUZZMUTATION ppMutation);
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorCorpusExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                    uint8_t *pbBuf, size_t cbBuf);
+static DECLCALLBACK(int) rtFuzzCtxMutatorBitFlipExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                     uint8_t *pbBuf, size_t cbBuf);
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteReplaceExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                         uint8_t *pbBuf, size_t cbBuf);
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteInsertExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                        uint8_t *pbBuf, size_t cbBuf);
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteSequenceInsertAppendExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                                      uint8_t *pbBuf, size_t cbBuf);
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteDeleteExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                        uint8_t *pbBuf, size_t cbBuf);
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteSequenceDeleteExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                                uint8_t *pbBuf, size_t cbBuf);
+static DECLCALLBACK(int) rtFuzzCtxMutatorIntegerReplaceExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                            uint8_t *pbBuf, size_t cbBuf);
+static DECLCALLBACK(int) rtFuzzCtxMutatorCrossoverExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                       uint8_t *pbBuf, size_t cbBuf);
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorExportDefault(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                       PFNRTFUZZCTXEXPORT pfnExport, void *pvUser);
+static DECLCALLBACK(int) rtFuzzCtxMutatorImportDefault(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, void *pvMutation,
+                                                      PFNRTFUZZCTXIMPORT pfnImport, void *pvUser);
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorCrossoverExport(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                         PFNRTFUZZCTXEXPORT pfnExport, void *pvUser);
+static DECLCALLBACK(int) rtFuzzCtxMutatorCrossoverImport(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, void *pvMutation,
+                                                         PFNRTFUZZCTXIMPORT pfnImport, void *pvUser);
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+
+/** Signed 8bit interesting values. */
+static int8_t s_ai8Interesting[]    = { INT8_MIN, INT8_MIN + 1, -1, 0, 1, INT8_MAX - 1, INT8_MAX };
+/** Unsigned 8bit interesting values. */
+static uint8_t s_au8Interesting[]   = { 0, 1, UINT8_MAX - 1, UINT8_MAX };
+/** Signed 16bit interesting values. */
+static int16_t s_ai16Interesting[]  = { INT16_MIN, INT16_MIN + 1, -1, 0, 1, INT16_MAX - 1, INT16_MAX };
+/** Unsigned 16bit interesting values. */
+static uint16_t s_au16Interesting[] = { 0, 1, UINT16_MAX - 1, UINT16_MAX };
+/** Signed 32bit interesting values. */
+static int32_t s_ai32Interesting[]  = { INT32_MIN, INT32_MIN + 1, -1, 0, 1, INT32_MAX - 1, INT32_MAX };
+/** Unsigned 32bit interesting values. */
+static uint32_t s_au32Interesting[] = { 0, 1, UINT32_MAX - 1, UINT32_MAX };
+/** Signed 64bit interesting values. */
+static int64_t s_ai64Interesting[]  = { INT64_MIN, INT64_MIN + 1, -1, 0, 1, INT64_MAX - 1, INT64_MAX };
+/** Unsigned 64bit interesting values. */
+static uint64_t s_au64Interesting[] = { 0, 1, UINT64_MAX - 1, UINT64_MAX };
+
+
+/**
+ * The special corpus mutator for the original data.
+ */
+static RTFUZZMUTATOR const g_MutatorCorpus =
+{
+    /** pszId */
+    "Corpus",
+    /** pszDesc */
+    "Special mutator, which is assigned to the initial corpus",
+    /** uMutator. */
+    RTFUZZMUTATOR_ID_CORPUS,
+    /** enmClass. */
+    RTFUZZMUTATORCLASS_BYTES,
+    /** fFlags */
+    RTFUZZMUTATOR_F_DEFAULT,
+    /** pfnPrep */
+    NULL,
+    /** pfnExec */
+    rtFuzzCtxMutatorCorpusExec,
+    /** pfnExport */
+    rtFuzzCtxMutatorExportDefault,
+    /** pfnImport */
+    rtFuzzCtxMutatorImportDefault
+};
+
+/**
+ * Array of all available mutators.
+ */
+static RTFUZZMUTATOR const g_aMutators[] =
+{
+    /* pszId          pszDesc                                                uMutator     enmClass                     fFlags                      pfnPrep                                       pfnExec                                       pfnExport                        pfnImport                         */
+    { "BitFlip",      "Flips a single bit in the input",                     0,           RTFUZZMUTATORCLASS_BITS,     RTFUZZMUTATOR_F_DEFAULT,    rtFuzzCtxMutatorBitFlipPrep,                  rtFuzzCtxMutatorBitFlipExec,                  rtFuzzCtxMutatorExportDefault,   rtFuzzCtxMutatorImportDefault     },
+    { "ByteReplace",  "Replaces a single byte in the input",                 1,           RTFUZZMUTATORCLASS_BYTES,    RTFUZZMUTATOR_F_DEFAULT,    rtFuzzCtxMutatorByteReplacePrep,              rtFuzzCtxMutatorByteReplaceExec,              rtFuzzCtxMutatorExportDefault,   rtFuzzCtxMutatorImportDefault     },
+    { "ByteInsert",   "Inserts a single byte sequence into the input",       2,           RTFUZZMUTATORCLASS_BYTES,    RTFUZZMUTATOR_F_DEFAULT,    rtFuzzCtxMutatorByteInsertPrep,               rtFuzzCtxMutatorByteInsertExec,               rtFuzzCtxMutatorExportDefault,   rtFuzzCtxMutatorImportDefault     },
+    { "ByteSeqIns",   "Inserts a byte sequence in the input",                3,           RTFUZZMUTATORCLASS_BYTES,    RTFUZZMUTATOR_F_DEFAULT,    rtFuzzCtxMutatorByteSequenceInsertAppendPrep, rtFuzzCtxMutatorByteSequenceInsertAppendExec, rtFuzzCtxMutatorExportDefault,   rtFuzzCtxMutatorImportDefault     },
+    { "ByteSeqApp",   "Appends a byte sequence to the input",                4,           RTFUZZMUTATORCLASS_BYTES,    RTFUZZMUTATOR_F_END_OF_BUF, rtFuzzCtxMutatorByteSequenceInsertAppendPrep, rtFuzzCtxMutatorByteSequenceInsertAppendExec, rtFuzzCtxMutatorExportDefault,   rtFuzzCtxMutatorImportDefault     },
+    { "ByteDelete",   "Deletes a single byte sequence from the input",       5,           RTFUZZMUTATORCLASS_BYTES,    RTFUZZMUTATOR_F_DEFAULT,    rtFuzzCtxMutatorByteDeletePrep,               rtFuzzCtxMutatorByteDeleteExec,               NULL,                            NULL                              },
+    { "ByteSeqDel",   "Deletes a byte sequence from the input",              6,           RTFUZZMUTATORCLASS_BYTES,    RTFUZZMUTATOR_F_DEFAULT,    rtFuzzCtxMutatorByteSequenceDeletePrep,       rtFuzzCtxMutatorByteSequenceDeleteExec,       NULL,                            NULL                              },
+    { "IntReplace",   "Replaces a possible integer with an interesting one", 7,           RTFUZZMUTATORCLASS_INTEGERS, RTFUZZMUTATOR_F_DEFAULT,    rtFuzzCtxMutatorIntegerReplacePrep,           rtFuzzCtxMutatorIntegerReplaceExec,           rtFuzzCtxMutatorExportDefault,   rtFuzzCtxMutatorImportDefault     },
+    { "MutCrossover", "Creates a crossover of two other mutations",          8,           RTFUZZMUTATORCLASS_MUTATORS, RTFUZZMUTATOR_F_DEFAULT,    rtFuzzCtxMutatorCrossoverPrep,                rtFuzzCtxMutatorCrossoverExec,                rtFuzzCtxMutatorCrossoverExport, rtFuzzCtxMutatorCrossoverImport   }
+};
+
+
+/**
+ * Allocates the given number of bytes.
+ *
+ * @returns Pointer to the allocated memory
+ * @param   pThis               The fuzzer context instance.
+ * @param   cb                  How much to allocate.
+ */
+static void *rtFuzzCtxMemoryAlloc(PRTFUZZCTXINT pThis, size_t cb)
+{
+    AssertReturn(cb > 0, NULL);
+
+    PRTFUZZMEMHDR pMemHdr = (PRTFUZZMEMHDR)RTMemAllocZ(cb + sizeof(RTFUZZMEMHDR));
+    if (RT_LIKELY(pMemHdr))
+    {
+        pMemHdr->cb = cb;
+        size_t cbIgn = ASMAtomicAddZ(&pThis->cbMemTotal, cb + sizeof(RTFUZZMEMHDR)); RT_NOREF(cbIgn);
+        return pMemHdr + 1;
+    }
+
+    return NULL;
+}
+
+
+/**
+ * Frees the given memory.
+ *
+ * @returns nothing.
+ * @param   pThis               The fuzzer context instance.
+ * @param   pv                  Pointer to the memory area to free.
+ */
+static void rtFuzzCtxMemoryFree(PRTFUZZCTXINT pThis, void *pv)
+{
+    AssertReturnVoid(pv != NULL);
+    PRTFUZZMEMHDR pMemHdr = ((PRTFUZZMEMHDR)pv) - 1;
+
+    size_t cbIgn = ASMAtomicSubZ(&pThis->cbMemTotal, pMemHdr->cb + sizeof(RTFUZZMEMHDR)); RT_NOREF(cbIgn);
+    RTMemFree(pMemHdr);
+}
+
+
+/**
+ * Frees the cached inputs until the given amount is free.
+ *
+ * @returns Whether the amount of memory is free.
+ * @param   pThis               The fuzzer context instance.
+ * @param   cb                  How many bytes to reclaim
+ */
+static bool rtFuzzCtxMutationAllocReclaim(PRTFUZZCTXINT pThis, size_t cb)
+{
+    while (   !RTListIsEmpty(&pThis->LstMutationsAlloc)
+           && pThis->cbMutationsAlloc + cb > pThis->cbMutationsAllocMax)
+    {
+        PRTFUZZMUTATION pMutation = RTListGetLast(&pThis->LstMutationsAlloc, RTFUZZMUTATION, NdAlloc);
+        AssertPtr(pMutation);
+        AssertPtr(pMutation->pvInput);
+
+        rtFuzzCtxMemoryFree(pThis, pMutation->pvInput);
+        pThis->cbMutationsAlloc -= pMutation->cbAlloc;
+        pMutation->pvInput = NULL;
+        pMutation->cbAlloc = 0;
+        pMutation->fCached = false;
+        RTListNodeRemove(&pMutation->NdAlloc);
+    }
+
+    return pThis->cbMutationsAlloc + cb <= pThis->cbMutationsAllocMax;
+}
+
+
+/**
+ * Updates the cache status of the given mutation.
+ *
+ * @returns nothing.
+ * @param   pThis               The fuzzer context instance.
+ * @param   pMutation           The mutation to update.
+ */
+static void rtFuzzCtxMutationMaybeEnterCache(PRTFUZZCTXINT pThis, PRTFUZZMUTATION pMutation)
+{
+    RTCritSectEnter(&pThis->CritSectAlloc);
+
+    /* Initial corpus mutations are not freed. */
+    if (   pMutation->pvInput
+        && pMutation->pMutator != &g_MutatorCorpus)
+    {
+        Assert(!pMutation->fCached);
+
+        if (rtFuzzCtxMutationAllocReclaim(pThis, pMutation->cbAlloc))
+        {
+            RTListPrepend(&pThis->LstMutationsAlloc, &pMutation->NdAlloc);
+            pThis->cbMutationsAlloc += pMutation->cbAlloc;
+            pMutation->fCached = true;
+        }
+        else
+        {
+            rtFuzzCtxMemoryFree(pThis, pMutation->pvInput);
+            pMutation->pvInput = NULL;
+            pMutation->cbAlloc = 0;
+            pMutation->fCached = false;
+        }
+    }
+    RTCritSectLeave(&pThis->CritSectAlloc);
+}
+
+
+/**
+ * Removes a cached mutation from the cache.
+ *
+ * @returns nothing.
+ * @param   pThis               The fuzzer context instance.
+ * @param   pMutation           The mutation to remove.
+ */
+static void rtFuzzCtxMutationCacheRemove(PRTFUZZCTXINT pThis, PRTFUZZMUTATION pMutation)
+{
+    RTCritSectEnter(&pThis->CritSectAlloc);
+    if (pMutation->fCached)
+    {
+        RTListNodeRemove(&pMutation->NdAlloc);
+        pThis->cbMutationsAlloc -= pMutation->cbAlloc;
+        pMutation->fCached = false;
+    }
+    RTCritSectLeave(&pThis->CritSectAlloc);
+}
+
+
+/**
+ * Destroys the given mutation.
+ *
+ * @returns nothing.
+ * @param   pMutation           The mutation to destroy.
+ */
+static void rtFuzzMutationDestroy(PRTFUZZMUTATION pMutation)
+{
+    if (pMutation->pvInput)
+    {
+        rtFuzzCtxMemoryFree(pMutation->pFuzzer, pMutation->pvInput);
+        if (pMutation->fCached)
+        {
+            RTCritSectEnter(&pMutation->pFuzzer->CritSectAlloc);
+            RTListNodeRemove(&pMutation->NdAlloc);
+            pMutation->pFuzzer->cbMutationsAlloc -= pMutation->cbAlloc;
+            RTCritSectLeave(&pMutation->pFuzzer->CritSectAlloc);
+        }
+        pMutation->pvInput = NULL;
+        pMutation->cbAlloc = 0;
+        pMutation->fCached = false;
+    }
+    rtFuzzCtxMemoryFree(pMutation->pFuzzer, pMutation);
+}
+
+
+/**
+ * Retains an external reference to the given mutation.
+ *
+ * @returns New reference count on success.
+ * @param   pMutation           The mutation to retain.
+ */
+static uint32_t rtFuzzMutationRetain(PRTFUZZMUTATION pMutation)
+{
+    uint32_t cRefs = ASMAtomicIncU32(&pMutation->cRefs);
+    AssertMsg(   (   cRefs > 1
+                  || pMutation->fInTree)
+              && cRefs < _1M, ("%#x %p\n", cRefs, pMutation));
+
+    if (cRefs == 1)
+        rtFuzzCtxMutationCacheRemove(pMutation->pFuzzer, pMutation);
+    return cRefs;
+}
+
+
+/**
+ * Releases an external reference from the given mutation.
+ *
+ * @returns New reference count on success.
+ * @param   pMutation           The mutation to retain.
+ */
+static uint32_t rtFuzzMutationRelease(PRTFUZZMUTATION pMutation)
+{
+    uint32_t cRefs = ASMAtomicDecU32(&pMutation->cRefs);
+    AssertMsg(cRefs < _1M, ("%#x %p\n", cRefs, pMutation));
+
+    if (cRefs == 0)
+    {
+        if (!pMutation->fInTree)
+            rtFuzzMutationDestroy(pMutation);
+        else
+            rtFuzzCtxMutationMaybeEnterCache(pMutation->pFuzzer, pMutation);
+    }
+
+    return cRefs;
+}
+
+
+/**
+ * Adds the given mutation to the corpus of the given fuzzer context.
+ *
+ * @returns IPRT status code.
+ * @param   pThis               The fuzzer context instance.
+ * @param   pMutation           The mutation to add.
+ */
+static int rtFuzzCtxMutationAdd(PRTFUZZCTXINT pThis, PRTFUZZMUTATION pMutation)
+{
+    int rc = VINF_SUCCESS;
+
+    pMutation->Core.Key = ASMAtomicIncU64(&pThis->cMutations);
+    rc = RTSemRWRequestWrite(pThis->hSemRwMutations, RT_INDEFINITE_WAIT);
+    AssertRC(rc); RT_NOREF(rc);
+    bool fIns = RTAvlU64Insert(&pThis->TreeMutations, &pMutation->Core);
+    Assert(fIns); RT_NOREF(fIns);
+    rc = RTSemRWReleaseWrite(pThis->hSemRwMutations);
+    AssertRC(rc); RT_NOREF(rc);
+
+    pMutation->fInTree = true;
+    return rc;
+}
+
+
+/**
+ * Locates the mutation with the given key.
+ *
+ * @returns Pointer to the mutation if found or NULL otherwise.
+ * @param   pThis               The fuzzer context instance.
+ * @param   uKey                The key to locate.
+ */
+static PRTFUZZMUTATION rtFuzzCtxMutationLocate(PRTFUZZCTXINT pThis, uint64_t uKey)
+{
+    int rc = RTSemRWRequestRead(pThis->hSemRwMutations, RT_INDEFINITE_WAIT);
+    AssertRC(rc); RT_NOREF(rc);
+
+    /*
+     * Using best fit getter here as there might be a racing mutation insertion and the mutation counter has increased
+     * already but the mutation is not yet in the tree.
+     */
+    PRTFUZZMUTATION pMutation = (PRTFUZZMUTATION)RTAvlU64GetBestFit(&pThis->TreeMutations, uKey, false /*fAbove*/);
+    if (RT_LIKELY(pMutation))
+        rtFuzzMutationRetain(pMutation);
+
+    rc = RTSemRWReleaseRead(pThis->hSemRwMutations);
+    AssertRC(rc); RT_NOREF(rc);
+
+    return pMutation;
+}
+
+
+/**
+ * Returns a random mutation from the corpus of the given fuzzer context.
+ *
+ * @returns Pointer to a randomly picked mutation (reference count is increased).
+ * @param   pThis               The fuzzer context instance.
+ */
+static PRTFUZZMUTATION rtFuzzCtxMutationPickRnd(PRTFUZZCTXINT pThis)
+{
+    uint64_t idxMutation = RTRandAdvU64Ex(pThis->hRand, 1, ASMAtomicReadU64(&pThis->cMutations));
+    return rtFuzzCtxMutationLocate(pThis, idxMutation);
+}
+
+
+/**
+ * Creates a new mutation capable of holding the additional number of bytes.
+ *
+ * @returns Pointer to the newly created mutation or NULL if out of memory.
+ * @param   pThis               The fuzzer context instance.
+ * @param   offMutation         The starting offset for the mutation.
+ * @param   pMutationParent     The parent mutation, can be NULL.
+ * @param   cbAdditional        Additional number of bytes to allocate after the core structure.
+ * @param   ppvMutation         Where to store the pointer to the mutation dependent data on success.
+ */
+static PRTFUZZMUTATION rtFuzzMutationCreate(PRTFUZZCTXINT pThis, uint64_t offMutation, PRTFUZZMUTATION pMutationParent,
+                                            size_t cbAdditional, void **ppvMutation)
+{
+    PRTFUZZMUTATION pMutation = (PRTFUZZMUTATION)rtFuzzCtxMemoryAlloc(pThis, sizeof(RTFUZZMUTATION) + cbAdditional);
+    if (RT_LIKELY(pMutation))
+    {
+        pMutation->u32Magic        = 0; /** @todo */
+        pMutation->pFuzzer         = pThis;
+        pMutation->cRefs           = 1;
+        pMutation->iLvl            = 0;
+        pMutation->offMutation     = offMutation;
+        pMutation->pMutationParent = pMutationParent;
+        pMutation->cbMutation      = cbAdditional;
+        pMutation->fInTree         = false;
+        pMutation->fCached         = false;
+        pMutation->pvInput         = NULL;
+        pMutation->cbInput         = 0;
+        pMutation->cbAlloc         = 0;
+
+        if (pMutationParent)
+            pMutation->iLvl = pMutationParent->iLvl + 1;
+        if (ppvMutation)
+            *ppvMutation = &pMutation->abMutation[0];
+    }
+
+    return pMutation;
+}
+
+
+/**
+ * Destroys the given fuzzer context freeing all allocated resources.
+ *
+ * @returns nothing.
+ * @param   pThis               The fuzzer context instance.
+ */
+static void rtFuzzCtxDestroy(PRTFUZZCTXINT pThis)
+{
+    RT_NOREF(pThis);
+}
+
+
+/**
+ * Creates the final input data applying all accumulated mutations.
+ *
+ * @returns IPRT status code.
+ * @param   pMutation           The mutation to finalize.
+ */
+static int rtFuzzMutationDataFinalize(PRTFUZZMUTATION pMutation)
+{
+    if (pMutation->pvInput)
+        return VINF_SUCCESS;
+
+    /* Traverse the mutations top to bottom and insert into the array. */
+    int rc = VINF_SUCCESS;
+    uint32_t idx = pMutation->iLvl + 1;
+    PRTFUZZMUTATION *papMutations = (PRTFUZZMUTATION *)RTMemTmpAlloc(idx * sizeof(PCRTFUZZMUTATION));
+    if (RT_LIKELY(papMutations))
+    {
+        PRTFUZZMUTATION pMutationCur = pMutation;
+        size_t cbAlloc = 0;
+
+        /*
+         * As soon as a mutation with allocated input data is encountered the insertion is
+         * stopped as it contains all necessary mutated inputs we can start from.
+         */
+        while (idx > 0)
+        {
+            rtFuzzMutationRetain(pMutationCur);
+            papMutations[idx - 1] = pMutationCur;
+            cbAlloc = RT_MAX(cbAlloc, pMutationCur->cbInput);
+            if (pMutationCur->pvInput)
+            {
+                idx--;
+                break;
+            }
+            pMutationCur = pMutationCur->pMutationParent;
+            idx--;
+        }
+
+        pMutation->cbAlloc = cbAlloc;
+        uint8_t *pbBuf = (uint8_t *)rtFuzzCtxMemoryAlloc(pMutation->pFuzzer, cbAlloc);
+        if (RT_LIKELY(pbBuf))
+        {
+            pMutation->pvInput = pbBuf;
+
+            /* Copy the initial input data. */
+            size_t cbInputNow = papMutations[idx]->cbInput;
+            memcpy(pbBuf, papMutations[idx]->pvInput, cbInputNow);
+            rtFuzzMutationRelease(papMutations[idx]);
+
+            for (uint32_t i = idx + 1; i < pMutation->iLvl + 1; i++)
+            {
+                PRTFUZZMUTATION pCur = papMutations[i];
+                pCur->pMutator->pfnExec(pCur->pFuzzer, pCur, (void *)&pCur->abMutation[0],
+                                        pbBuf + pCur->offMutation,
+                                        cbInputNow - pCur->offMutation);
+
+                cbInputNow = pCur->cbInput;
+                rtFuzzMutationRelease(pCur);
+            }
+
+            Assert(cbInputNow == pMutation->cbInput);
+        }
+        else
+            rc = VERR_NO_MEMORY;
+
+        RTMemTmpFree(papMutations);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+/**
+ * Default mutator export callback (just writing the raw data).
+ */
+static DECLCALLBACK(int) rtFuzzCtxMutatorExportDefault(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                       PFNRTFUZZCTXEXPORT pfnExport, void *pvUser)
+{
+    return pfnExport(pThis, pvMutation, pMutation->cbMutation, pvUser);
+}
+
+
+/**
+ * Default mutator import callback (just reading the raw data).
+ */
+static DECLCALLBACK(int) rtFuzzCtxMutatorImportDefault(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, void *pvMutation,
+                                                       PFNRTFUZZCTXIMPORT pfnImport, void *pvUser)
+{
+    return pfnImport(pThis, pvMutation, pMutation->cbMutation, NULL, pvUser);
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorCorpusExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                    uint8_t *pbBuf, size_t cbBuf)
+{
+    RT_NOREF(pThis, cbBuf, pvMutation);
+    memcpy(pbBuf, pvMutation, pMutation->cbInput);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Mutator callback - flips a single bit in the input.
+ */
+static DECLCALLBACK(int) rtFuzzCtxMutatorBitFlipPrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                     PPRTFUZZMUTATION ppMutation)
+{
+    int rc = VINF_SUCCESS;
+    uint8_t *pidxBitFlip = 0;
+    PRTFUZZMUTATION pMutation = rtFuzzMutationCreate(pThis, offStart, pMutationParent, sizeof(*pidxBitFlip), (void **)&pidxBitFlip);
+    if (RT_LIKELY(pMutation))
+    {
+        pMutation->cbInput = pMutationParent->cbInput; /* Bit flips don't change the input size. */
+        *pidxBitFlip = (uint8_t)RTRandAdvU32Ex(pThis->hRand, 0, sizeof(uint8_t) * 8 - 1);
+        *ppMutation = pMutation;
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorBitFlipExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                     uint8_t *pbBuf, size_t cbBuf)
+{
+    RT_NOREF(pThis, cbBuf, pMutation);
+    uint8_t idxBitFlip = *(uint8_t *)pvMutation;
+    ASMBitToggle(pbBuf, idxBitFlip);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Mutator callback - replaces a single byte in the input.
+ */
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteReplacePrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                         PPRTFUZZMUTATION ppMutation)
+{
+    int rc = VINF_SUCCESS;
+    uint8_t *pbReplace = 0;
+    PRTFUZZMUTATION pMutation = rtFuzzMutationCreate(pThis, offStart, pMutationParent, sizeof(*pbReplace), (void **)&pbReplace);
+    if (RT_LIKELY(pMutation))
+    {
+        pMutation->cbInput = pMutationParent->cbInput; /* Byte replacements don't change the input size. */
+        RTRandAdvBytes(pThis->hRand, pbReplace, 1); /** @todo Filter out same values. */
+        *ppMutation = pMutation;
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteReplaceExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                         uint8_t *pbBuf, size_t cbBuf)
+{
+    RT_NOREF(pThis, cbBuf, pMutation);
+    uint8_t bReplace = *(uint8_t *)pvMutation;
+    *pbBuf = bReplace;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Mutator callback - inserts a single byte into the input.
+ */
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteInsertPrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                        PPRTFUZZMUTATION ppMutation)
+{
+    int rc = VINF_SUCCESS;
+    uint8_t *pbInsert = 0;
+    if (pMutationParent->cbInput < pThis->cbInputMax)
+    {
+        PRTFUZZMUTATION pMutation = rtFuzzMutationCreate(pThis, offStart, pMutationParent, 1 /*cbAdditional*/, (void **)&pbInsert);
+        if (RT_LIKELY(pMutation))
+        {
+            pMutation->cbInput = pMutationParent->cbInput + 1;
+            RTRandAdvBytes(pThis->hRand, pbInsert, 1);
+            *ppMutation = pMutation;
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+
+    return rc;
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteInsertExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                        uint8_t *pbBuf, size_t cbBuf)
+{
+    RT_NOREF(pThis, pMutation, pvMutation);
+
+    /* Just move the residual data one byte to the back. */
+    memmove(pbBuf + 1, pbBuf, cbBuf);
+    *pbBuf = *(uint8_t *)pvMutation;
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Mutator callback - inserts a byte sequence into the input.
+ */
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteSequenceInsertAppendPrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                                      PPRTFUZZMUTATION ppMutation)
+{
+    int rc = VINF_SUCCESS;
+    if (pMutationParent->cbInput < pThis->cbInputMax)
+    {
+        size_t cbInputMutated = (size_t)RTRandAdvU64Ex(pThis->hRand, pMutationParent->cbInput + 1, pThis->cbInputMax);
+        size_t cbInsert = cbInputMutated - pMutationParent->cbInput;
+        uint8_t *pbAdd = NULL;
+
+        PRTFUZZMUTATION pMutation = rtFuzzMutationCreate(pThis, offStart, pMutationParent, cbInsert, (void **)&pbAdd);
+        if (RT_LIKELY(pMutation))
+        {
+            pMutation->cbInput = cbInputMutated;
+            RTRandAdvBytes(pThis->hRand, pbAdd, cbInsert);
+            *ppMutation = pMutation;
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+
+    return rc;
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteSequenceInsertAppendExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                                      uint8_t *pbBuf, size_t cbBuf)
+{
+    RT_NOREF(pThis);
+    size_t cbInsert = pMutation->cbInput - pMutation->pMutationParent->cbInput;
+
+    /* Move any remaining data to the end. */
+    if (cbBuf)
+        memmove(pbBuf + cbInsert, pbBuf, cbBuf);
+
+    memcpy(pbBuf, pvMutation, cbInsert);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Mutator callback - deletes a single byte in the input.
+ */
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteDeletePrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                        PPRTFUZZMUTATION ppMutation)
+{
+    int rc = VINF_SUCCESS;
+    if (pMutationParent->cbInput - offStart >= 1)
+    {
+        PRTFUZZMUTATION pMutation = rtFuzzMutationCreate(pThis, offStart, pMutationParent, 0 /*cbAdditional*/, NULL);
+        if (RT_LIKELY(pMutation))
+        {
+            pMutation->cbInput = pMutationParent->cbInput - 1;
+            *ppMutation = pMutation;
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+
+    return rc;
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteDeleteExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                        uint8_t *pbBuf, size_t cbBuf)
+{
+    RT_NOREF(pThis, pMutation, pvMutation);
+
+    /* Just move the residual data to the front. */
+    memmove(pbBuf, pbBuf + 1, cbBuf - 1);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Mutator callback - deletes a byte sequence in the input.
+ */
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteSequenceDeletePrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                                PPRTFUZZMUTATION ppMutation)
+{
+    int rc = VINF_SUCCESS;
+    if (   pMutationParent->cbInput > offStart
+        && pMutationParent->cbInput > 1)
+    {
+        size_t cbInputMutated = (size_t)RTRandAdvU64Ex(pThis->hRand, offStart, pMutationParent->cbInput - 1);
+
+        PRTFUZZMUTATION pMutation = rtFuzzMutationCreate(pThis, offStart, pMutationParent, 0 /*cbAdditional*/, NULL);
+        if (RT_LIKELY(pMutation))
+        {
+            pMutation->cbInput = cbInputMutated;
+            *ppMutation = pMutation;
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+
+    return rc;
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorByteSequenceDeleteExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                                uint8_t *pbBuf, size_t cbBuf)
+{
+    RT_NOREF(pThis, pvMutation);
+    Assert(pMutation->pMutationParent->cbInput > pMutation->cbInput);
+    size_t cbDel = pMutation->pMutationParent->cbInput - pMutation->cbInput;
+
+    /* Just move the residual data to the front. */
+    memmove(pbBuf, pbBuf + cbDel, cbBuf - cbDel);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Mutator callback - replaces a possible integer with something interesting.
+ */
+static DECLCALLBACK(int) rtFuzzCtxMutatorIntegerReplacePrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                            PPRTFUZZMUTATION ppMutation)
+{
+    int rc = VINF_SUCCESS;
+    PRTFUZZMUTATORINTEGER pMutInt = NULL;
+    PRTFUZZMUTATION pMutation = rtFuzzMutationCreate(pThis, offStart, pMutationParent, sizeof(*pMutInt), (void **)&pMutInt);
+    if (RT_LIKELY(pMutation))
+    {
+        size_t cbLeft = pMutationParent->cbInput - offStart;
+        uint32_t uClassMax = 0;
+
+        switch (cbLeft)
+        {
+            case 1:
+                uClassMax = 1;
+                break;
+            case 2:
+            case 3:
+                uClassMax = 3;
+                break;
+            case 4:
+            case 5:
+            case 6:
+            case 7:
+                uClassMax = 5;
+                break;
+            default:
+                uClassMax = 7;
+                break;
+        }
+
+        pMutInt->uIntClass = (uint8_t)RTRandAdvU32Ex(pThis->hRand, 0, uClassMax);
+        pMutInt->fByteSwap = RT_BOOL(RTRandAdvU32Ex(pThis->hRand, 0, 1));
+
+        switch (pMutInt->uIntClass)
+        {
+            case 0:
+                pMutInt->idxInt = (uint16_t)RTRandAdvU32Ex(pThis->hRand, 0, RT_ELEMENTS(s_ai8Interesting) - 1);
+                break;
+            case 1:
+                pMutInt->idxInt = (uint16_t)RTRandAdvU32Ex(pThis->hRand, 0, RT_ELEMENTS(s_au8Interesting) - 1);
+                break;
+            case 2:
+                pMutInt->idxInt = (uint16_t)RTRandAdvU32Ex(pThis->hRand, 0, RT_ELEMENTS(s_ai16Interesting) - 1);
+                break;
+            case 3:
+                pMutInt->idxInt = (uint16_t)RTRandAdvU32Ex(pThis->hRand, 0, RT_ELEMENTS(s_au16Interesting) - 1);
+                break;
+            case 4:
+                pMutInt->idxInt = (uint16_t)RTRandAdvU32Ex(pThis->hRand, 0, RT_ELEMENTS(s_ai32Interesting) - 1);
+                break;
+            case 5:
+                pMutInt->idxInt = (uint16_t)RTRandAdvU32Ex(pThis->hRand, 0, RT_ELEMENTS(s_au32Interesting) - 1);
+                break;
+            case 6:
+                pMutInt->idxInt = (uint16_t)RTRandAdvU32Ex(pThis->hRand, 0, RT_ELEMENTS(s_ai64Interesting) - 1);
+                break;
+            case 7:
+                pMutInt->idxInt = (uint16_t)RTRandAdvU32Ex(pThis->hRand, 0, RT_ELEMENTS(s_au64Interesting) - 1);
+                break;
+            default:
+                AssertReleaseFailed();
+        }
+
+        pMutation->cbInput = pMutationParent->cbInput;
+        *ppMutation = pMutation;
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorIntegerReplaceExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                            uint8_t *pbBuf, size_t cbBuf)
+{
+    RT_NOREF(pThis, pMutation, cbBuf);
+    union
+    {
+        int8_t   i8;
+        uint8_t  u8;
+        int16_t  i16;
+        uint16_t u16;
+        int32_t  i32;
+        uint32_t u32;
+        int64_t  i64;
+        uint64_t u64;
+    } Int;
+    PCRTFUZZMUTATORINTEGER pMutInt = (PCRTFUZZMUTATORINTEGER)pvMutation;
+    size_t cb = 0;
+
+    switch (pMutInt->uIntClass)
+    {
+        case 0:
+            Int.i8 = s_ai8Interesting[pMutInt->idxInt];
+            cb = 1;
+            break;
+        case 1:
+            Int.u8 = s_au8Interesting[pMutInt->idxInt];
+            cb = 1;
+            break;
+        case 2:
+            Int.i16 = s_ai16Interesting[pMutInt->idxInt];
+            cb = 2;
+            if (pMutInt->fByteSwap)
+                Int.u16 = RT_BSWAP_U16(Int.u16);
+            break;
+        case 3:
+            Int.u16 = s_au16Interesting[pMutInt->idxInt];
+            cb = 2;
+            if (pMutInt->fByteSwap)
+                Int.u16 = RT_BSWAP_U16(Int.u16);
+            break;
+        case 4:
+            Int.i32 = s_ai32Interesting[pMutInt->idxInt];
+            cb = 4;
+            if (pMutInt->fByteSwap)
+                Int.u32 = RT_BSWAP_U32(Int.u32);
+            break;
+        case 5:
+            Int.u32 = s_au32Interesting[pMutInt->idxInt];
+            cb = 4;
+            if (pMutInt->fByteSwap)
+                Int.u32 = RT_BSWAP_U32(Int.u32);
+            break;
+        case 6:
+            Int.i64 = s_ai64Interesting[pMutInt->idxInt];
+            cb = 8;
+            if (pMutInt->fByteSwap)
+                Int.u64 = RT_BSWAP_U64(Int.u64);
+            break;
+        case 7:
+            Int.u64 = s_au64Interesting[pMutInt->idxInt];
+            cb = 8;
+            if (pMutInt->fByteSwap)
+                Int.u64 = RT_BSWAP_U64(Int.u64);
+            break;
+        default:
+            AssertReleaseFailed();
+    }
+
+    memcpy(pbBuf, &Int, cb);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Mutator callback - crosses over two mutations at the given point.
+ */
+static DECLCALLBACK(int) rtFuzzCtxMutatorCrossoverPrep(PRTFUZZCTXINT pThis, uint64_t offStart, PRTFUZZMUTATION pMutationParent,
+                                                       PPRTFUZZMUTATION ppMutation)
+{
+    int rc = VINF_SUCCESS;
+
+    if (pThis->cMutations > 1)
+    {
+        uint64_t *pidxMutCrossover = NULL;
+        PRTFUZZMUTATION pMutation = rtFuzzMutationCreate(pThis, offStart, pMutationParent, sizeof(*pidxMutCrossover), (void **)&pidxMutCrossover);
+        if (RT_LIKELY(pMutation))
+        {
+            uint32_t cTries = 10;
+            PRTFUZZMUTATION pMutCrossover = NULL;
+            /*
+             * Pick a random mutation to crossover with (making sure it is not the current one
+             * or the crossover point is beyond the end of input).
+             */
+            do
+            {
+                if (pMutCrossover)
+                    rtFuzzMutationRelease(pMutCrossover);
+                pMutCrossover = rtFuzzCtxMutationPickRnd(pThis);
+                cTries--;
+            } while (   (   pMutCrossover == pMutationParent
+                         || offStart >= pMutCrossover->cbInput)
+                     && cTries > 0);
+
+            if (cTries)
+            {
+                pMutation->cbInput = pMutCrossover->cbInput;
+                *pidxMutCrossover = pMutCrossover->Core.Key;
+                *ppMutation = pMutation;
+            }
+            else
+                rtFuzzMutationDestroy(pMutation);
+
+            rtFuzzMutationRelease(pMutCrossover);
+        }
+        else
+            rc = VERR_NO_MEMORY;
+    }
+
+    return rc;
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorCrossoverExec(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                       uint8_t *pbBuf, size_t cbBuf)
+{
+    RT_NOREF(cbBuf);
+    uint64_t idxMutCrossover = *(uint64_t *)pvMutation;
+
+    PRTFUZZMUTATION pMutCrossover = rtFuzzCtxMutationLocate(pThis, idxMutCrossover);
+    int rc = rtFuzzMutationDataFinalize(pMutCrossover);
+    if (RT_SUCCESS(rc))
+    {
+        memcpy(pbBuf, (uint8_t *)pMutCrossover->pvInput + pMutation->offMutation,
+               pMutCrossover->cbInput - pMutation->offMutation);
+        rtFuzzMutationRelease(pMutCrossover);
+    }
+
+    return rc;
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorCrossoverExport(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, const void *pvMutation,
+                                                         PFNRTFUZZCTXEXPORT pfnExport, void *pvUser)
+{
+    RT_NOREF(pMutation);
+
+    uint64_t idxMutCrossover = *(uint64_t *)pvMutation;
+    idxMutCrossover = RT_H2LE_U64(idxMutCrossover);
+    return pfnExport(pThis, &idxMutCrossover, sizeof(idxMutCrossover), pvUser);
+}
+
+
+static DECLCALLBACK(int) rtFuzzCtxMutatorCrossoverImport(PRTFUZZCTXINT pThis, PCRTFUZZMUTATION pMutation, void *pvMutation,
+                                                         PFNRTFUZZCTXIMPORT pfnImport, void *pvUser)
+{
+    RT_NOREF(pMutation);
+
+    uint64_t uKey = 0;
+    int rc = pfnImport(pThis, &uKey, sizeof(uKey), NULL, pvUser);
+    if (RT_SUCCESS(rc))
+    {
+        uKey = RT_LE2H_U64(uKey);
+        *(uint64_t *)pvMutation = uKey;
+    }
+
+    return rc;
+}
+
+
+/**
+ * Creates an empty fuzzing context.
+ *
+ * @returns IPRT status code.
+ * @param   ppThis              Where to store the pointer to the internal fuzzing context instance on success.
+ * @param   enmType             Fuzzing context type.
+ */
+static int rtFuzzCtxCreateEmpty(PRTFUZZCTXINT *ppThis, RTFUZZCTXTYPE enmType)
+{
+    int rc;
+    PRTFUZZCTXINT pThis = (PRTFUZZCTXINT)RTMemAllocZ(sizeof(*pThis));
+    if (RT_LIKELY(pThis))
+    {
+        pThis->u32Magic            = RTFUZZCTX_MAGIC;
+        pThis->cRefs               = 1;
+        pThis->enmType             = enmType;
+        pThis->TreeMutations       = NULL;
+        pThis->cbInputMax          = UINT32_MAX;
+        pThis->cMutations          = 0;
+        pThis->fFlagsBehavioral    = 0;
+        pThis->cbMutationsAllocMax = _1G;
+        pThis->cbMemTotal          = 0;
+        RTListInit(&pThis->LstMutationsAlloc);
+
+        /* Copy the default mutator descriptors over. */
+        pThis->paMutators = (PRTFUZZMUTATOR)RTMemAllocZ(RT_ELEMENTS(g_aMutators) * sizeof(RTFUZZMUTATOR));
+        if (RT_LIKELY(pThis->paMutators))
+        {
+            pThis->cMutators = RT_ELEMENTS(g_aMutators);
+            memcpy(&pThis->paMutators[0], &g_aMutators[0], RT_ELEMENTS(g_aMutators) * sizeof(RTFUZZMUTATOR));
+
+            rc = RTSemRWCreate(&pThis->hSemRwMutations);
+            if (RT_SUCCESS(rc))
+            {
+                rc = RTCritSectInit(&pThis->CritSectAlloc);
+                if (RT_SUCCESS(rc))
+                {
+                    rc = RTRandAdvCreateParkMiller(&pThis->hRand);
+                    if (RT_SUCCESS(rc))
+                    {
+                        RTRandAdvSeed(pThis->hRand, RTTimeSystemNanoTS());
+                        *ppThis = pThis;
+                        return VINF_SUCCESS;
+                    }
+
+                    RTCritSectDelete(&pThis->CritSectAlloc);
+                }
+
+                RTSemRWDestroy(pThis->hSemRwMutations);
+            }
+        }
+        else
+            rc = VERR_NO_MEMORY;
+
+        RTMemFree(pThis);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+/**
+ * Destroys the given fuzzing input.
+ *
+ * @returns nothing.
+ * @param   pThis               The fuzzing input to destroy.
+ */
+static void rtFuzzInputDestroy(PRTFUZZINPUTINT pThis)
+{
+    PRTFUZZCTXINT pFuzzer = pThis->pFuzzer;
+
+    rtFuzzMutationRelease(pThis->pMutationTop);
+    rtFuzzCtxMemoryFree(pFuzzer, pThis);
+    RTFuzzCtxRelease(pFuzzer);
+}
+
+
+RTDECL(int) RTFuzzCtxCreate(PRTFUZZCTX phFuzzCtx, RTFUZZCTXTYPE enmType)
+{
+    AssertPtrReturn(phFuzzCtx, VERR_INVALID_POINTER);
+
+    return rtFuzzCtxCreateEmpty(phFuzzCtx, enmType);
+}
+
+
+RTDECL(int) RTFuzzCtxCreateFromState(PRTFUZZCTX phFuzzCtx, PFNRTFUZZCTXIMPORT pfnImport, void *pvUser)
+{
+    AssertPtrReturn(phFuzzCtx, VERR_INVALID_POINTER);
+    AssertPtrReturn(pfnImport, VERR_INVALID_POINTER);
+
+#if 0
+    int rc = VINF_SUCCESS;
+    if (cbState >= sizeof(RTFUZZCTXSTATE))
+    {
+        RTFUZZCTXSTATE StateImport;
+
+        memcpy(&StateImport, pvState, sizeof(RTFUZZCTXSTATE));
+        if (   RT_LE2H_U32(StateImport.u32Magic) == RTFUZZCTX_MAGIC
+            && RT_LE2H_U32(StateImport.cbPrng) <= cbState - sizeof(RTFUZZCTXSTATE))
+        {
+            PRTFUZZCTXINT pThis = rtFuzzCtxCreateEmpty();
+            if (RT_LIKELY(pThis))
+            {
+                pThis->cbInputMax       = (size_t)RT_LE2H_U64(StateImport.cbInputMax);
+                pThis->fFlagsBehavioral = RT_LE2H_U32(StateImport.fFlagsBehavioral);
+
+                uint8_t *pbState = (uint8_t *)pvState;
+                uint32_t cInputs = RT_LE2H_U32(StateImport.cInputs);
+                rc = RTRandAdvRestoreState(pThis->hRand, (const char *)&pbState[sizeof(RTFUZZCTXSTATE)]);
+                if (RT_SUCCESS(rc))
+                {
+                    /* Go through the inputs and add them. */
+                    pbState += sizeof(RTFUZZCTXSTATE) + RT_LE2H_U32(StateImport.cbPrng);
+                    cbState -= sizeof(RTFUZZCTXSTATE) + RT_LE2H_U32(StateImport.cbPrng);
+
+                    uint32_t idx = 0;
+                    while (   idx < cInputs
+                           && RT_SUCCESS(rc))
+                    {
+                        size_t cbInput = 0;
+                        if (cbState >= sizeof(uint32_t))
+                        {
+                            memcpy(&cbInput, pbState, sizeof(uint32_t));
+                            cbInput = RT_LE2H_U32(cbInput);
+                            pbState += sizeof(uint32_t);
+                        }
+
+                        if (   cbInput
+                            && cbInput <= cbState)
+                        {
+                            PRTFUZZINPUTINT pInput = rtFuzzCtxInputCreate(pThis, cbInput);
+                            if (RT_LIKELY(pInput))
+                            {
+                                memcpy(&pInput->abInput[0], pbState, cbInput);
+                                RTMd5(&pInput->abInput[0], pInput->cbInput, &pInput->abMd5Hash[0]);
+                                rc = rtFuzzCtxInputAdd(pThis, pInput);
+                                if (RT_FAILURE(rc))
+                                    RTMemFree(pInput);
+                                pbState += cbInput;
+                            }
+                        }
+                        else
+                            rc = VERR_INVALID_STATE;
+
+                        idx++;
+                    }
+
+                    if (RT_SUCCESS(rc))
+                    {
+                        *phFuzzCtx = pThis;
+                        return VINF_SUCCESS;
+                    }
+                }
+
+                rtFuzzCtxDestroy(pThis);
+            }
+            else
+                rc = VERR_NO_MEMORY;
+        }
+        else
+            rc = VERR_INVALID_MAGIC;
+    }
+    else
+        rc = VERR_INVALID_MAGIC;
+
+    return rc;
+#else
+    RT_NOREF(pvUser);
+    return VERR_NOT_IMPLEMENTED;
+#endif
+}
+
+
+RTDECL(int) RTFuzzCtxCreateFromStateMem(PRTFUZZCTX phFuzzCtx, const void *pvState, size_t cbState)
+{
+    AssertPtrReturn(phFuzzCtx, VERR_INVALID_POINTER);
+    AssertPtrReturn(pvState, VERR_INVALID_POINTER);
+    AssertPtrReturn(cbState, VERR_INVALID_POINTER);
+
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+RTDECL(int) RTFuzzCtxCreateFromStateFile(PRTFUZZCTX phFuzzCtx, const char *pszFilename)
+{
+    AssertPtrReturn(phFuzzCtx, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszFilename, VERR_INVALID_POINTER);
+
+    void *pv = NULL;
+    size_t cb = 0;
+    int rc = RTFileReadAll(pszFilename, &pv, &cb);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTFuzzCtxCreateFromStateMem(phFuzzCtx, pv, cb);
+        RTFileReadAllFree(pv, cb);
+    }
+
+    return rc;
+}
+
+
+RTDECL(uint32_t) RTFuzzCtxRetain(RTFUZZCTX hFuzzCtx)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    AssertMsg(cRefs > 1 && cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    return cRefs;
+}
+
+
+RTDECL(uint32_t) RTFuzzCtxRelease(RTFUZZCTX hFuzzCtx)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    if (pThis == NIL_RTFUZZCTX)
+        return 0;
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    AssertMsg(cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    if (cRefs == 0)
+        rtFuzzCtxDestroy(pThis);
+    return cRefs;
+}
+
+
+RTDECL(int) RTFuzzCtxQueryStats(RTFUZZCTX hFuzzCtx, PRTFUZZCTXSTATS pStats)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertPtrReturn(pStats, VERR_INVALID_POINTER);
+
+    pStats->cbMemory   = ASMAtomicReadZ(&pThis->cbMemTotal);
+    pStats->cMutations = ASMAtomicReadU64(&pThis->cMutations);
+    return VINF_SUCCESS;
+}
+
+
+/**
+ * Fuzzing context export callback for a single mutation.
+ */
+static DECLCALLBACK(int) rtFuzzCtxStateExportMutations(PAVLU64NODECORE pCore, void *pvParam)
+{
+    PRTFUZZMUTATION pMutation = (PRTFUZZMUTATION)pCore;
+    PCRTFUZZMUTATOR pMutator = pMutation->pMutator;
+    PCRTFUZZEXPORTARGS pArgs = (PCRTFUZZEXPORTARGS)pvParam;
+    RTFUZZMUTATIONSTATE MutationState;
+
+    MutationState.u64Id           = RT_H2LE_U64(pMutation->Core.Key);
+    if (pMutation->pMutationParent)
+        MutationState.u64IdParent = RT_H2LE_U64(pMutation->pMutationParent->Core.Key);
+    else
+        MutationState.u64IdParent = RT_H2LE_U64(0);
+    MutationState.u64OffMutation  = RT_H2LE_U64(pMutation->offMutation);
+    MutationState.cbInput         = RT_H2LE_U64((uint64_t)pMutation->cbInput);
+    MutationState.cbMutation      = RT_H2LE_U64((uint64_t)pMutation->cbMutation);
+    MutationState.u32IdMutator    = RT_H2LE_U32(pMutator->uMutator);
+    MutationState.iLvl            = RT_H2LE_U32(pMutation->iLvl);
+    MutationState.u32Magic        = RT_H2LE_U32(pMutation->u32Magic);
+
+    int rc = pArgs->pfnExport(pMutation->pFuzzer, &MutationState, sizeof(MutationState), pArgs->pvUser);
+    if (   RT_SUCCESS(rc)
+        && pMutator->pfnExport)
+        rc = pMutator->pfnExport(pMutation->pFuzzer, pMutation, &pMutation->abMutation[0], pArgs->pfnExport, pArgs->pvUser);
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzCtxStateExport(RTFUZZCTX hFuzzCtx, PFNRTFUZZCTXEXPORT pfnExport, void *pvUser)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+    AssertPtrReturn(pfnExport, VERR_INVALID_POINTER);
+
+    char aszPrngExport[_4K]; /* Should be plenty of room here. */
+    size_t cbPrng = sizeof(aszPrngExport);
+    int rc = RTRandAdvSaveState(pThis->hRand, &aszPrngExport[0], &cbPrng);
+    if (RT_SUCCESS(rc))
+    {
+        RTFUZZCTXSTATE StateExport;
+
+        StateExport.u32Magic         = RT_H2LE_U32(RTFUZZCTX_MAGIC);
+        switch (pThis->enmType)
+        {
+            case RTFUZZCTXTYPE_BLOB:
+                StateExport.uCtxType = RT_H2LE_U32(RTFUZZCTX_STATE_TYPE_BLOB);
+                break;
+            case RTFUZZCTXTYPE_STREAM:
+                StateExport.uCtxType = RT_H2LE_U32(RTFUZZCTX_STATE_TYPE_STREAM);
+                break;
+            default:
+                AssertFailed();
+                break;
+        }
+        StateExport.cbPrng           = RT_H2LE_U32((uint32_t)cbPrng);
+        StateExport.cMutations       = RT_H2LE_U32(pThis->cMutations);
+        StateExport.cMutators        = RT_H2LE_U32(pThis->cMutators);
+        StateExport.fFlagsBehavioral = RT_H2LE_U32(pThis->fFlagsBehavioral);
+        StateExport.cbInputMax       = RT_H2LE_U64(pThis->cbInputMax);
+
+        /* Write the context state and PRNG state first. */
+        rc = pfnExport(pThis, &StateExport, sizeof(StateExport), pvUser);
+        if (RT_SUCCESS(rc))
+            rc = pfnExport(pThis, &aszPrngExport[0], cbPrng, pvUser);
+        if (RT_SUCCESS(rc))
+        {
+            /* Write the mutator descriptors next. */
+            for (uint32_t i = 0; i < pThis->cMutators && RT_SUCCESS(rc); i++)
+            {
+                PRTFUZZMUTATOR pMutator = &pThis->paMutators[i];
+                uint32_t cchId = (uint32_t)strlen(pMutator->pszId) + 1;
+                uint32_t cchIdW = RT_H2LE_U32(cchId);
+
+                rc = pfnExport(pThis, &cchIdW, sizeof(cchIdW), pvUser);
+                if (RT_SUCCESS(rc))
+                    rc = pfnExport(pThis, &pMutator->pszId[0], cchId, pvUser);
+            }
+        }
+
+        /* Write the mutations last. */
+        if (RT_SUCCESS(rc))
+        {
+            RTFUZZEXPORTARGS Args;
+
+            Args.pfnExport = pfnExport;
+            Args.pvUser    = pvUser;
+            rc = RTAvlU64DoWithAll(&pThis->TreeMutations, true /*fFromLeft*/, rtFuzzCtxStateExportMutations, &Args);
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzCtxStateExportToMem(RTFUZZCTX hFuzzCtx, void **ppvState, size_t *pcbState)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+    AssertPtrReturn(ppvState, VERR_INVALID_POINTER);
+    AssertPtrReturn(pcbState, VERR_INVALID_POINTER);
+
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+/**
+ * Export to file callback.
+ */
+static DECLCALLBACK(int) rtFuzzCtxStateExportFile(RTFUZZCTX hFuzzCtx, const void *pvBuf, size_t cbWrite, void *pvUser)
+{
+    RT_NOREF(hFuzzCtx);
+
+    RTFILE hFile = (RTFILE)pvUser;
+    return RTFileWrite(hFile, pvBuf, cbWrite, NULL);
+}
+
+
+RTDECL(int) RTFuzzCtxStateExportToFile(RTFUZZCTX hFuzzCtx, const char *pszFilename)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszFilename, VERR_INVALID_POINTER);
+
+    RTFILE hFile;
+    int rc = RTFileOpen(&hFile, pszFilename, RTFILE_O_CREATE | RTFILE_O_WRITE | RTFILE_O_DENY_NONE);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTFuzzCtxStateExport(hFuzzCtx, rtFuzzCtxStateExportFile, hFile);
+        RTFileClose(hFile);
+        if (RT_FAILURE(rc))
+            RTFileDelete(pszFilename);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzCtxCorpusInputAdd(RTFUZZCTX hFuzzCtx, const void *pvInput, size_t cbInput)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+    AssertPtrReturn(pvInput, VERR_INVALID_POINTER);
+    AssertReturn(cbInput, VERR_INVALID_POINTER);
+
+    int rc = VINF_SUCCESS;
+    void *pvCorpus = NULL;
+    PRTFUZZMUTATION pMutation = rtFuzzMutationCreate(pThis, 0, NULL, cbInput, &pvCorpus);
+    if (RT_LIKELY(pMutation))
+    {
+        pMutation->pMutator = &g_MutatorCorpus;
+        pMutation->cbInput  = cbInput;
+        pMutation->pvInput  = pvCorpus;
+        memcpy(pvCorpus, pvInput, cbInput);
+        rc = rtFuzzCtxMutationAdd(pThis, pMutation);
+        if (RT_FAILURE(rc))
+            rtFuzzMutationDestroy(pMutation);
+    }
+    else
+        rc = VERR_NO_MEMORY;
+
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzCtxCorpusInputAddFromFile(RTFUZZCTX hFuzzCtx, const char *pszFilename)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszFilename, VERR_INVALID_POINTER);
+
+    void *pv = NULL;
+    size_t cb = 0;
+    int rc = RTFileReadAll(pszFilename, &pv, &cb);
+    if (RT_SUCCESS(rc))
+    {
+        rc = RTFuzzCtxCorpusInputAdd(hFuzzCtx, pv, cb);
+        RTFileReadAllFree(pv, cb);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzCtxCorpusInputAddFromVfsFile(RTFUZZCTX hFuzzCtx, RTVFSFILE hVfsFile)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(hVfsFile != NIL_RTVFSFILE, VERR_INVALID_HANDLE);
+
+    uint64_t cbFile = 0;
+    void *pvCorpus = NULL;
+    int rc = RTVfsFileQuerySize(hVfsFile, &cbFile);
+    if (RT_SUCCESS(rc))
+    {
+        PRTFUZZMUTATION pMutation = rtFuzzMutationCreate(pThis, 0, NULL, cbFile, &pvCorpus);
+        if (RT_LIKELY(pMutation))
+        {
+            pMutation->pMutator = &g_MutatorCorpus;
+            pMutation->cbInput  = cbFile;
+            pMutation->pvInput  = pvCorpus;
+            rc = RTVfsFileRead(hVfsFile, pvCorpus, cbFile, NULL);
+            if (RT_SUCCESS(rc))
+                rc = rtFuzzCtxMutationAdd(pThis, pMutation);
+
+            if (RT_FAILURE(rc))
+                rtFuzzMutationDestroy(pMutation);
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzCtxCorpusInputAddFromDirPath(RTFUZZCTX hFuzzCtx, const char *pszDirPath)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszDirPath, VERR_INVALID_POINTER);
+
+    RTDIR hDir;
+    int rc = RTDirOpen(&hDir, pszDirPath);
+    if (RT_SUCCESS(rc))
+    {
+        for (;;)
+        {
+            RTDIRENTRY DirEntry;
+            rc = RTDirRead(hDir, &DirEntry, NULL);
+            if (RT_FAILURE(rc))
+                break;
+
+            /* Skip '.', '..' and other non-files. */
+            if (   DirEntry.enmType != RTDIRENTRYTYPE_UNKNOWN
+                && DirEntry.enmType != RTDIRENTRYTYPE_FILE)
+                continue;
+            if (RTDirEntryIsStdDotLink(&DirEntry))
+                continue;
+
+            /* Compose the full path, result 'unknown' entries and skip non-files. */
+            char szFile[RTPATH_MAX];
+            RT_ZERO(szFile);
+            rc = RTPathJoin(szFile, sizeof(szFile), pszDirPath, DirEntry.szName);
+            if (RT_FAILURE(rc))
+                break;
+
+            if (DirEntry.enmType == RTDIRENTRYTYPE_UNKNOWN)
+            {
+                RTDirQueryUnknownType(szFile, false, &DirEntry.enmType);
+                if (DirEntry.enmType != RTDIRENTRYTYPE_FILE)
+                    continue;
+            }
+
+            /* Okay, it's a file we can add. */
+            rc = RTFuzzCtxCorpusInputAddFromFile(hFuzzCtx, szFile);
+            if (RT_FAILURE(rc))
+                break;
+        }
+        if (rc == VERR_NO_MORE_FILES)
+            rc = VINF_SUCCESS;
+        RTDirClose(hDir);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzCtxCfgSetInputSeedMaximum(RTFUZZCTX hFuzzCtx, size_t cbMax)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+
+    pThis->cbInputMax = cbMax;
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(size_t) RTFuzzCtxCfgGetInputSeedMaximum(RTFUZZCTX hFuzzCtx)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, 0);
+
+    return pThis->cbInputMax;
+}
+
+
+RTDECL(int) RTFuzzCtxCfgSetBehavioralFlags(RTFUZZCTX hFuzzCtx, uint32_t fFlags)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(!(fFlags & ~RTFUZZCTX_F_BEHAVIORAL_VALID), VERR_INVALID_PARAMETER);
+
+    pThis->fFlagsBehavioral = fFlags;
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(uint32_t) RTFuzzCfgGetBehavioralFlags(RTFUZZCTX hFuzzCtx)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, 0);
+
+    return pThis->fFlagsBehavioral;
+}
+
+
+RTDECL(int) RTFuzzCtxCfgSetTmpDirectory(RTFUZZCTX hFuzzCtx, const char *pszPathTmp)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+    AssertPtrReturn(pszPathTmp, VERR_INVALID_POINTER);
+
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+RTDECL(const char *) RTFuzzCtxCfgGetTmpDirectory(RTFUZZCTX hFuzzCtx)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, NULL);
+
+    return NULL;
+}
+
+
+RTDECL(int) RTFuzzCtxReseed(RTFUZZCTX hFuzzCtx, uint64_t uSeed)
+{
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+
+    RTRandAdvSeed(pThis->hRand, uSeed);
+    return VINF_SUCCESS;
+}
+
+
+RTDECL(int) RTFuzzCtxInputGenerate(RTFUZZCTX hFuzzCtx, PRTFUZZINPUT phFuzzInput)
+{
+    int rc = VINF_SUCCESS;
+    PRTFUZZCTXINT pThis = hFuzzCtx;
+    AssertPtrReturn(pThis, VERR_INVALID_POINTER);
+    AssertPtrReturn(phFuzzInput, VERR_INVALID_POINTER);
+
+    uint32_t cTries = 0;
+    PRTFUZZMUTATION pMutationParent = rtFuzzCtxMutationPickRnd(pThis);
+    do
+    {
+        uint32_t idxMutator = RTRandAdvU32Ex(pThis->hRand, 0, pThis->cMutators - 1);
+        PCRTFUZZMUTATOR pMutator = &pThis->paMutators[idxMutator];
+        PRTFUZZMUTATION pMutation = NULL;
+
+        uint64_t offStart = 0;
+        if (!(pMutator->fFlags & RTFUZZMUTATOR_F_END_OF_BUF))
+            offStart = RTRandAdvU64Ex(pThis->hRand, 0, pMutationParent->cbInput - 1);
+        else
+            offStart = pMutationParent->cbInput;
+
+        rc = pMutator->pfnPrep(pThis, offStart, pMutationParent, &pMutation);
+        if (   RT_SUCCESS(rc)
+            && VALID_PTR(pMutation))
+        {
+            pMutation->pMutator = pMutator;
+
+            if (pThis->fFlagsBehavioral & RTFUZZCTX_F_BEHAVIORAL_ADD_INPUT_AUTOMATICALLY_TO_CORPUS)
+                rtFuzzCtxMutationAdd(pThis, pMutation);
+
+            /* Create a new input. */
+            PRTFUZZINPUTINT pInput = (PRTFUZZINPUTINT)rtFuzzCtxMemoryAlloc(pThis, sizeof(RTFUZZINPUTINT));
+            if (RT_LIKELY(pInput))
+            {
+                pInput->u32Magic     = 0; /** @todo */
+                pInput->cRefs        = 1;
+                pInput->pFuzzer      = pThis;
+                pInput->pMutationTop = pMutation;
+                RTFuzzCtxRetain(pThis);
+
+                rtFuzzMutationRelease(pMutationParent);
+                *phFuzzInput = pInput;
+                return rc;
+            }
+            else
+                rc = VERR_NO_MEMORY;
+        }
+    } while (++cTries <= 50);
+
+    rtFuzzMutationRelease(pMutationParent);
+    if (RT_SUCCESS(rc))
+        rc = VERR_INVALID_STATE;
+
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzInputQueryBlobData(RTFUZZINPUT hFuzzInput, void **ppv, size_t *pcb)
+{
+    PRTFUZZINPUTINT pThis = hFuzzInput;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->pFuzzer->enmType == RTFUZZCTXTYPE_BLOB, VERR_INVALID_STATE);
+
+    int rc = VINF_SUCCESS;
+    if (!pThis->pMutationTop->pvInput)
+        rc = rtFuzzMutationDataFinalize(pThis->pMutationTop);
+
+    if (RT_SUCCESS(rc))
+    {
+        *ppv = pThis->pMutationTop->pvInput;
+        *pcb = pThis->pMutationTop->cbInput;
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzInputMutateStreamData(RTFUZZINPUT hFuzzInput, void *pvBuf, size_t cbBuf)
+{
+    PRTFUZZINPUTINT pThis = hFuzzInput;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->pFuzzer->enmType == RTFUZZCTXTYPE_STREAM, VERR_INVALID_STATE);
+
+    RT_NOREF(pvBuf, cbBuf);
+    return VERR_NOT_IMPLEMENTED;
+}
+
+
+RTDECL(uint32_t) RTFuzzInputRetain(RTFUZZINPUT hFuzzInput)
+{
+    PRTFUZZINPUTINT pThis = hFuzzInput;
+
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
+    AssertMsg(cRefs > 1 && cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    return cRefs;
+}
+
+
+RTDECL(uint32_t) RTFuzzInputRelease(RTFUZZINPUT hFuzzInput)
+{
+    PRTFUZZINPUTINT pThis = hFuzzInput;
+    if (pThis == NIL_RTFUZZINPUT)
+        return 0;
+    AssertPtrReturn(pThis, UINT32_MAX);
+
+    uint32_t cRefs = ASMAtomicDecU32(&pThis->cRefs);
+    AssertMsg(cRefs < _1M, ("%#x %p\n", cRefs, pThis));
+    if (cRefs == 0)
+        rtFuzzInputDestroy(pThis);
+    return cRefs;
+}
+
+
+RTDECL(int) RTFuzzInputQueryDigestString(RTFUZZINPUT hFuzzInput, char *pszDigest, size_t cchDigest)
+{
+    PRTFUZZINPUTINT pThis = hFuzzInput;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->pFuzzer->enmType == RTFUZZCTXTYPE_BLOB, VERR_INVALID_STATE);
+    AssertPtrReturn(pszDigest, VERR_INVALID_POINTER);
+    AssertReturn(cchDigest >= RTMD5_STRING_LEN + 1, VERR_INVALID_PARAMETER);
+
+    int rc = VINF_SUCCESS;
+    if (!pThis->pMutationTop->pvInput)
+        rc = rtFuzzMutationDataFinalize(pThis->pMutationTop);
+
+    if (RT_SUCCESS(rc))
+    {
+        uint8_t abHash[RTMD5_HASH_SIZE];
+        RTMd5(pThis->pMutationTop->pvInput, pThis->pMutationTop->cbInput, &abHash[0]);
+        rc = RTMd5ToString(&abHash[0], pszDigest, cchDigest);
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzInputWriteToFile(RTFUZZINPUT hFuzzInput, const char *pszFilename)
+{
+    PRTFUZZINPUTINT pThis = hFuzzInput;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+    AssertReturn(pThis->pFuzzer->enmType == RTFUZZCTXTYPE_BLOB, VERR_INVALID_STATE);
+    AssertPtrReturn(pszFilename, VERR_INVALID_POINTER);
+
+    int rc = VINF_SUCCESS;
+    if (!pThis->pMutationTop->pvInput)
+        rc = rtFuzzMutationDataFinalize(pThis->pMutationTop);
+
+    if (RT_SUCCESS(rc))
+    {
+        RTFILE hFile;
+        rc = RTFileOpen(&hFile, pszFilename, RTFILE_O_CREATE | RTFILE_O_WRITE | RTFILE_O_DENY_NONE);
+        if (RT_SUCCESS(rc))
+        {
+            rc = RTFileWrite(hFile, pThis->pMutationTop->pvInput, pThis->pMutationTop->cbInput, NULL);
+            AssertRC(rc);
+            RTFileClose(hFile);
+
+            if (RT_FAILURE(rc))
+                RTFileDelete(pszFilename);
+        }
+    }
+
+    return rc;
+}
+
+
+RTDECL(int) RTFuzzInputAddToCtxCorpus(RTFUZZINPUT hFuzzInput)
+{
+    PRTFUZZINPUTINT pThis = hFuzzInput;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+
+    return rtFuzzCtxMutationAdd(pThis->pFuzzer, pThis->pMutationTop);
+}
+
+
+RTDECL(int) RTFuzzInputRemoveFromCtxCorpus(RTFUZZINPUT hFuzzInput)
+{
+    PRTFUZZINPUTINT pThis = hFuzzInput;
+    AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
+
+#if 0
+    int rc = VINF_SUCCESS;
+    PRTFUZZINTERMEDIATE pIntermediate = NULL;
+    PRTFUZZINPUTINT pInputLoc = rtFuzzCtxInputLocate(pThis->pFuzzer, &pThis->abMd5Hash[0], true /*fExact*/,
+                                                     &pIntermediate);
+    if (pInputLoc)
+    {
+        AssertPtr(pIntermediate);
+        Assert(pInputLoc == pThis);
+
+        uint64_t u64Md5Low = *(uint64_t *)&pThis->abMd5Hash[0];
+        RTAvlU64Remove(&pIntermediate->TreeSeedsLow, u64Md5Low);
+        RTFuzzInputRelease(hFuzzInput);
+    }
+    else
+        rc = VERR_NOT_FOUND;
+#endif
+
+    return VERR_NOT_IMPLEMENTED;
+}
+