Tracking down a memory error.

The store memory address is being overrun in the call to `<<`.
This commit is contained in:
Kyle Isom 2023-10-09 15:23:23 -07:00
parent 372de925df
commit b2e0e849ef
8 changed files with 272 additions and 209 deletions

264
Arena.cc
View File

@ -1,6 +1,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#if defined(__linux__)
#include <sys/mman.h>
@ -10,59 +11,61 @@
#include <unistd.h>
#endif
#if defined(DESKTOP_BUILD)
#include <iostream>
#include <ios>
#endif
#include "Arena.h"
#define ARENA_UNINIT 0
#define ARENA_STATIC 1
#define ARENA_ALLOC 2
#if defined(__linux__)
#define ARENA_MMAP 3
#define PROT_RW PROT_READ|PROT_WRITE
#endif
namespace klib {
Arena::Arena()
: store(nullptr), size(0), fd(0), arenaType(ARENA_UNINIT)
{}
Arena::~Arena()
{
this->Destroy();
}
void
InitializeArena(Arena &arena)
Arena::Initialize()
{
arena.Store = NULL;
arena.Size = 0;
arena.Type = ARENA_UNINIT;
arena.fd = 0;
assert(this->arenaType != ARENA_UNINIT);
this->store = nullptr;
this->size = 0;
this->arenaType = ARENA_UNINIT;
this->fd = 0;
}
int
NewStaticArena(Arena &arena, uint8_t *mem, size_t size)
Arena::SetStatic(uint8_t *mem, size_t allocSize)
{
arena.Store = mem;
arena.Size = size;
arena.Type = ARENA_STATIC;
this->store = mem;
this->size = allocSize;
this->arenaType = ARENA_STATIC;
return 0;
}
int
AllocNewArena(Arena & arena, size_t size)
Arena::SetAlloc(size_t allocSize)
{
if (arena.Size > 0) {
if (DestroyArena(arena) != 0) {
return -1;
}
if (this->size > 0) {
this->Destroy();
}
arena.Type = ARENA_ALLOC;
arena.Size = size;
arena.Store = (uint8_t *)calloc(sizeof(uint8_t), size);
if (arena.Store == NULL) {
this->arenaType = ARENA_ALLOC;
this->size = allocSize;
this->store = new uint8_t[allocSize];
if (this->store == nullptr) {
return -1;
}
this->Clear();
return 0;
}
@ -71,19 +74,19 @@ AllocNewArena(Arena & arena, size_t size)
int
MMapArena(Arena &arena, int fd, size_t size)
{
if (arena.Size > 0) {
if (this->size > 0) {
if (DestroyArena(arena) != 0) {
return -1;
}
}
arena.Type = ARENA_MMAP;
arena.Size = size;
arena.Store = (uint8_t *)mmap(NULL, size, PROT_RW, MAP_SHARED, fd, 0);
if ((void *)arena.Store == MAP_FAILED) {
this->arenaType = ARENA_MMAP;
this->size = size;
this->store = (uint8_t *)mmap(NULL, size, PROT_RW, MAP_SHARED, fd, 0);
if ((void *)this->store == MAP_FAILED) {
return -1;
}
arena.fd = fd;
this->fd = fd;
return 0;
}
@ -93,7 +96,7 @@ OpenArena(Arena &arena, const char *path)
{
struct stat st;
if (arena.Size > 0) {
if (this->size > 0) {
if (DestroyArena(arena) != 0) {
return -1;
}
@ -103,12 +106,12 @@ OpenArena(Arena &arena, const char *path)
return -1;
}
arena.fd = open(path, O_RDWR);
if (arena.fd == -1) {
this->fd = open(path, O_RDWR);
if (this->fd == -1) {
return -1;
}
return MMapArena(arena, arena.fd, (size_t)st.st_size);
return MMapArena(arena, this->fd, (size_t)st.st_size);
}
@ -117,7 +120,7 @@ CreateArena(Arena &arena, const char *path, size_t size, mode_t mode)
{
int fd = 0;
if (arena.Size > 0) {
if (this->size > 0) {
if (DestroyArena(arena) != 0) {
return -1;
}
@ -139,115 +142,132 @@ CreateArena(Arena &arena, const char *path, size_t size, mode_t mode)
#endif
bool
Arena::CursorInArena(uint8_t *cursor)
{
if (cursor < this->store) {
return false;
}
if (cursor >= this->End()) {
return false;
}
return true;
}
/*
* ClearArena clears the memory being used, removing any data
* present. It does not free the memory; it is effectively a
* wrapper around memset.
*/
void
ClearArena(Arena &arena)
Arena::Clear()
{
if (arena.Size == 0) {
if (this->size == 0) {
return;
}
memset(arena.Store, 0, arena.Size);
memset(this->store, 0, this->size);
}
int
DestroyArena(Arena &arena)
{
if (arena.Type == ARENA_UNINIT) {
return 0;
}
switch (arena.Type) {
case ARENA_STATIC:
break;
case ARENA_ALLOC:
free(arena.Store);
break;
#if defined(__linux__)
case ARENA_MMAP:
if (munmap(arena.Store, arena.Size) == -1) {
return -1;
}
if (close(arena.fd) == -1) {
return -1;
}
arena.fd = 0;
break;
#endif
default:
#if defined(NDEBUG)
return -1;
#else
abort();
#endif
}
arena.Type = ARENA_UNINIT;
arena.Size = 0;
arena.Store = NULL;
return 0;
}
#if defined(DESKTOP_BUILD)
void
DisplayArena(const Arena &arena)
Arena::Destroy()
{
std::cout << "Arena @ 0x";
std::cout << std::hex << (uintptr_t)&arena << std::endl;
std::cout << std::dec;
std::cout << "\tStore is " << arena.Size << " bytes at address 0x";
std::cout << std::hex << (uintptr_t)&(arena.Store) << std::endl;
std::cout << "\tType: ";
if (this->arenaType == ARENA_UNINIT) {
return;
}
switch (arena.Type) {
case ARENA_UNINIT:
std::cout << "uninitialized";
break;
case ARENA_STATIC:
std::cout << "static";
break;
case ARENA_ALLOC:
std::cout << "allocated";
break;
switch (this->arenaType) {
case ARENA_STATIC:
break;
case ARENA_ALLOC:
delete this->store;
break;
#if defined(__linux__)
case ARENA_MMAP:
if (munmap(this->store, this->size) == -1) {
return -1;
}
if (close(this->fd) == -1) {
return -1;
}
this->fd = 0;
break;
#endif
default:
#if defined(NDEBUG)
return -1;
#else
abort();
#endif
}
this->arenaType = ARENA_UNINIT;
this->size = 0;
this->store = nullptr;
return;
}
std::ostream &
operator<<(std::ostream &os, const Arena arena)
{
auto cursor = arena.NewCursor();
char cursorString[17] = {0};
snprintf(cursorString, 16, "%0p", cursor);
os << "Arena<";
switch (arena.Type()) {
case ARENA_UNINIT:
os << "uninitialized";
break;
case ARENA_STATIC:
os << "static";
break;
case ARENA_ALLOC:
os << "allocated";
break;
#if defined(__linux__)
case ARENA_MMAP:
std::cout << "mmap/file";
break;
case ARENA_MMAP:
os << "mmap/file";
break;
#endif
default:
std::cout << "unknown (this is a bug)";
default:
os << "unknown (this is a bug)";
}
std::cout << std::endl;
}
#else
void
DisplayArena(const Arena &arena)
{
os << ">@0x";
os << std::hex << (uintptr_t) &arena;
os << std::dec;
os << ",store<" << arena.Size() << "B>@0x";
os << std::hex << cursorString;
os << std::dec;
return os;
}
#endif
int
WriteArena(const Arena &arena, const char *path)
Arena::Write(const char *path)
{
FILE *arenaFile = NULL;
int retc = -1;
FILE *arenaFile = NULL;
int retc = -1;
#if defined(__posix__)
arenaFile = fopen(path, "w");
if (arenaFile == NULL) {
#else
if (fopen_s(&arenaFile, path, "w") != 0) {
#endif
return -1;
}
if (fwrite(arena.Store, sizeof(*arena.Store), arena.Size,
arenaFile) == arena.Size) {
if (fwrite(this->store, sizeof(*this->store), this->size,
arenaFile) == this->size) {
retc = 0;
}
@ -258,3 +278,5 @@ WriteArena(const Arena &arena, const char *path)
return retc;
}
} // namespace klib

89
Arena.h
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@ -2,43 +2,82 @@
#define KIMODEM_ARENA_H
#include <iostream>
#include <sys/stat.h>
#include <cstddef>
#include <cstdint>
typedef struct {
uint8_t *Store;
size_t Size;
int fd;
uint8_t Type;
} Arena;
namespace klib {
/*
* InitializeArena is intended for use only with systems that
* do not initialize new variables to zero. It should be called
* exactly once, at the start of the program. Any other time the
* arena needs to be reset, it should be called with clear_arena
* or destroy_arena.
*/
void InitializeArena(Arena &arena);
int NewStaticArena(Arena &, uint8_t *, size_t);
int AllocNewArena(Arena &, size_t);
enum ArenaType : uint8_t {
ARENA_UNINIT,
ARENA_STATIC,
ARENA_ALLOC,
ARENA_MMAP,
};
class Arena {
public:
Arena();
~Arena();
/*
* InitializeArena is intended for use only with systems that
* do not initialize new variables to zero. It should be called
* exactly once, at the start of the program. Any other time the
* arena needs to be reset, it should be called with Clear or
* Destroy.
*/
void Initialize();
int SetStatic(uint8_t *, size_t);
int SetAlloc(size_t allocSize);
#if defined(__linux__)
int MMapArena(Arena &, int); /* arena will own fd */
int CreateArena(Arena &arena, const char *path, size_t size, mode_t mode);
int OpenArena(Arena &, const char *, size_t);
int MemoryMap(int fd); // Arena will own fd.
int Create(const char *path, size_t size, mode_t mode);
int Open(const char *, size_t);
#endif
void ClearArena(Arena &);
int DestroyArena(Arena &); /* dispose of any memory used by arena */
uint8_t *NewCursor() const { return this->store; }
uint8_t *End() { return this->store + this->size; }
bool CursorInArena(uint8_t *cursor);
/* DANGER: if arena is file backed (mmap or open), DO NOT WRITE TO THE
* BACKING FILE! */
int WriteArena(const Arena &arena, const char *path);
size_t Size() const
{ return this->size; }
void DisplayArena(const Arena &arena);
uint8_t Type() const
{ return this->arenaType; }
bool Ready() const { return this->Type() != ARENA_UNINIT; };
void Clear();
void Destroy(); /* dispose of any memory used by arena */
/*
* DANGER: if arena is file backed (mmap or open), DO NOT WRITE TO THE
* BACKING FILE!
*/
int Write(const char *path);
uint8_t &operator[](size_t index)
{ return this->store[index]; }
private:
uint8_t *store;
size_t size;
int fd;
ArenaType arenaType;
};
std::ostream &operator<<(std::ostream& os, Arena arena);
} // namespace klib
#endif

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@ -19,7 +19,7 @@ nearestPower(size_t x)
{
if (x == 0) {
return 0;
};
}
std::cout << "x -> ";
@ -80,6 +80,7 @@ Buffer::Append(uint8_t *data, size_t datalen)
resized = true;
}
assert(this->contents != nullptr);
memcpy(this->contents + this->length, data, datalen);
this->length += datalen;
return resized;
@ -142,17 +143,14 @@ Buffer::Resize(size_t newCapacity)
return;
}
uint8_t *newContents = new uint8_t[newCapacity];
auto newContents = new uint8_t[newCapacity];
memset(newContents, 0, newCapacity);
if (this->length > 0) {
memcpy(newContents, this->contents, this->length);
}
if (this->contents != nullptr) {
delete this->contents;
}
delete this->contents;
this->contents = newContents;
this->capacity = newCapacity;
}
@ -198,7 +196,7 @@ Buffer::Reclaim()
}
size_t
Buffer::mustGrow(size_t delta)
Buffer::mustGrow(size_t delta) const
{
if ((delta + this->length) < this->capacity) {
return 0;

View File

@ -41,7 +41,7 @@ public:
uint8_t &operator[](size_t index);
private:
size_t mustGrow(size_t delta);
size_t mustGrow(size_t delta) const;
bool shiftRight(size_t offset, size_t delta);
bool shiftLeft(size_t offset, size_t delta);

View File

@ -105,8 +105,8 @@ Dictionary::spaceAvailable(uint8_t klen, uint8_t vlen)
required += klen + 2;
required += vlen + 2;
remaining = (uintptr_t)cursor - (uintptr_t)arena.Store;
remaining = arena.Size - remaining;
remaining = (uintptr_t)cursor - (uintptr_t)arena.NewCursor();
remaining = arena.Size() - remaining;
return ((size_t)remaining >= required);
}
@ -115,7 +115,7 @@ Dictionary::spaceAvailable(uint8_t klen, uint8_t vlen)
void
Dictionary::DumpKVPairs()
{
uint8_t *cursor = (this->arena).Store;
uint8_t *cursor = (this->arena).NewCursor();
TLV::Record rec;
TLV::ReadFromMemory(rec, cursor);
@ -147,5 +147,5 @@ Dictionary::DumpKVPairs()
void
Dictionary::DumpToFile(const char *path)
{
WriteArena(this->arena, path);
this->arena.Write(path);
}

38
TLV.cc
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@ -1,33 +1,32 @@
#include <cstring>
#include "TLV.h"
using namespace klib;
#define REC_SIZE(x) ((std::size_t)x.Len + 2)
namespace klib {
namespace TLV {
static bool
spaceAvailable(Arena &arena, uint8_t *cursor, uint8_t len)
{
uintptr_t remaining = 0;
if (cursor == NULL) {
return false;
}
remaining = (uintptr_t)cursor - (uintptr_t)arena.Store;
remaining = arena.Size - remaining;
return ((size_t)remaining >= ((size_t)len+2));
return arena.CursorInArena(cursor + len);
}
static inline void
clearUnused(Record &rec)
{
uint8_t trail = TLV_MAX_LEN-rec.Len;
uint8_t trail = TLV_MAX_LEN - rec.Len;
memset(rec.Val+rec.Len, 0, trail);
memset(rec.Val + rec.Len, 0, trail);
}
@ -58,7 +57,7 @@ WriteToMemory(Arena &arena, uint8_t *cursor, Record &rec)
}
void
void
SetRecord(Record &rec, uint8_t tag, uint8_t len, const char *val)
{
rec.Tag = tag;
@ -73,7 +72,7 @@ ReadFromMemory(Record &rec, uint8_t *cursor)
{
rec.Tag = cursor[0];
rec.Len = cursor[1];
memcpy(rec.Val, cursor+2, rec.Len);
memcpy(rec.Val, cursor + 2, rec.Len);
clearUnused(rec);
}
@ -97,10 +96,10 @@ FindTag(Arena &arena, uint8_t *cursor, Record &rec)
uint8_t *
LocateTag(Arena &arena, uint8_t *cursor, Record &rec)
{
uint8_t tag, len;
uint8_t tag, len;
if (cursor == NULL) {
cursor = arena.Store;
cursor = arena.NewCursor();
}
while ((tag = cursor[0]) != rec.Tag) {
@ -124,19 +123,19 @@ LocateTag(Arena &arena, uint8_t *cursor, Record &rec)
uint8_t *
FindEmpty(Arena &arena, uint8_t *cursor) {
Record rec;
FindEmpty(Arena &arena, uint8_t *cursor)
{
Record rec;
rec.Tag = TAG_EMPTY;
return FindTag(arena, cursor, rec);
}
uint8_t *
uint8_t *
SkipRecord(Record &rec, uint8_t *cursor)
{
return (uint8_t *)((uintptr_t)cursor + rec.Len + 2);
return (uint8_t *) ((uintptr_t) cursor + rec.Len + 2);
}
@ -147,8 +146,8 @@ DeleteRecord(Arena &arena, uint8_t *cursor)
return;
}
uint8_t len = cursor[1] + 2;
uint8_t *stop = arena.Store + arena.Size;
uint8_t len = cursor[1] + 2;
uint8_t *stop = arena.NewCursor() + arena.Size();
stop -= len;
@ -166,3 +165,4 @@ DeleteRecord(Arena &arena, uint8_t *cursor)
} // namespace TLV
} // namespace klib

15
TLV.h
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@ -5,6 +5,8 @@
#include "Arena.h"
using namespace klib;
#ifndef TLV_MAX_LEN
#define TLV_MAX_LEN 253
@ -14,6 +16,7 @@
#define TAG_EMPTY 0
namespace klib {
namespace TLV {
@ -23,18 +26,17 @@ struct Record {
char Val[TLV_MAX_LEN];
};
uint8_t *WriteToMemory(Arena &, uint8_t *, Record &);
void ReadFromMemory(Record &, uint8_t *);
void SetRecord(Record &, uint8_t, uint8_t, const char *);
void DeleteRecord(Arena &, uint8_t *);
/*
* returns a pointer to memory where the record was found,
* e.g. LocateTag(...)[0] is the tag of the found record.
* FindTag will call LocateTag and then SkipRecord if the
* tag was found.
*/
* returns a pointer to memory where the record was found,
* e.g. LocateTag(...)[0] is the tag of the found record.
* FindTag will call LocateTag and then SkipRecord if the
* tag was found.
*/
uint8_t *FindTag(Arena &, uint8_t *, Record &);
uint8_t *LocateTag(Arena &, uint8_t *, Record &);
@ -43,6 +45,7 @@ uint8_t *SkipRecord(Record &, uint8_t *);
} // namespace TLV
} // namespace klib
#endif

View File

@ -11,63 +11,65 @@
static uint8_t arenaBuffer[ARENA_SIZE];
bool
void
tlvTestSuite(Arena &backend)
{
TLV::Record rec1, rec2, rec3, rec4;
uint8_t *cursor = NULL;
uint8_t *cursor = nullptr;
std::cout << "\tSetting first three records." << std::endl;
TLV::SetRecord(rec1, 1, TEST_STRLEN1, TEST_STR1);
TLV::SetRecord(rec2, 2, TEST_STRLEN2, TEST_STR2);
TLV::SetRecord(rec3, 1, TEST_STRLEN4, TEST_STR4);
rec4.Tag = 1;
assert(TLV::WriteToMemory(backend, cursor, rec1) != NULL);
assert((cursor = TLV::WriteToMemory(backend, cursor, rec2)) != NULL);
assert(TLV::WriteToMemory(backend, cursor, rec3) != NULL);
cursor = NULL;
std::cout << "\twriting new rec1" << std::endl;
assert(TLV::WriteToMemory(backend, cursor, rec1) != nullptr);
std::cout << "\twriting new rec2" << std::endl;
assert((cursor = TLV::WriteToMemory(backend, cursor, rec2)) != nullptr);
std::cout << "\twriting new rec3" << std::endl;
assert(TLV::WriteToMemory(backend, cursor, rec3) != nullptr);
cursor = nullptr;
// the cursor should point at the next record,
// and rec4 should contain the same data as rec1.
std::cout << "\tFindTag 1" << std::endl;
cursor = TLV::FindTag(backend, cursor, rec4);
assert(cursor != NULL);
assert(cursor != backend.Store);
assert(cursor != nullptr);
assert(cursor != backend.NewCursor());
assert(cmpRecord(rec1, rec4));
std::cout << "\tFindTag 2" << std::endl;
cursor = TLV::FindTag(backend, cursor, rec4);
assert(cursor != NULL);
assert(cursor != nullptr);
assert(cmpRecord(rec3, rec4));
TLV::SetRecord(rec4, 3, TEST_STRLEN3, TEST_STR3);
assert(TLV::WriteToMemory(backend, NULL, rec4));
assert(TLV::WriteToMemory(backend, nullptr, rec4));
rec4.Tag = 2;
cursor = TLV::FindTag(backend, NULL, rec4);
assert(cursor != NULL);
cursor = TLV::FindTag(backend, nullptr, rec4);
assert(cursor != nullptr);
TLV::DeleteRecord(backend, cursor);
assert(cursor[0] == 3);
return true;
}
bool
runSuite(Arena &backend, const char *label)
{
DisplayArena(backend);
std::cout << backend << std::endl;
std::cout << "running test suite " << label << ": ";
if (!tlvTestSuite(backend)) {
try {
tlvTestSuite(backend);
} catch (_exception){
std::cout << "FAILED" << std::endl;
return false;
}
std::cout << "OK" << std::endl;
std::cout << "\tdestroying arena: ";
if (DestroyArena(backend) != 0) {
std::cout << "FAILED" << std::endl;
return false;
}
backend.Destroy();
std::cout << "OK" << std::endl;
return true;
@ -83,15 +85,13 @@ main(int argc, const char *argv[])
Arena arenaMem;
std::cout << "TESTPROG: " << argv[0] << std::endl;
InitializeArena(arenaStatic);
InitializeArena(arenaMem);
if (-1 == NewStaticArena(arenaStatic, arenaBuffer, ARENA_SIZE)) {
if (-1 == arenaStatic.SetStatic(arenaBuffer, ARENA_SIZE)) {
abort();
} else if (!runSuite(arenaStatic, "arenaStatic")) {
abort();
}
ClearArena(arenaStatic);
arenaStatic.Clear();
#if defined(__linux__)
Arena arenaFile;
@ -104,11 +104,12 @@ main(int argc, const char *argv[])
}
#endif
if (-1 == AllocNewArena(arenaMem, ARENA_SIZE)) {
if (-1 == arenaMem.SetAlloc(ARENA_SIZE)) {
abort();
} else if (!runSuite(arenaMem, "arenaMem")) {
abort();
}
arenaMem.Clear();
std::cout << "OK" << std::endl;
return 0;