Leaked source code of windows server 2003
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

789 lines
19 KiB

/*++
Copyright (c) 1997 Microsoft Corporation
Module Name:
cache.c
Abstract:
Implements a cache mechanism to speed up OpenRegKeyStr.
Author:
Jim Schmidt (jimschm) 11-Sep-2000
Revisions:
<alias> <date> <comments>
--*/
#include "pch.h"
#include "migutilp.h"
#include "regp.h"
#define DBG_REG "Reg"
typedef struct {
HKEY Key;
BOOL Unicode;
UINT RefCount;
UINT ClosesNeeded;
REGSAM Sam;
UINT KeyStringBytes;
BYTE KeyString[];
} REGKEYCACHE, *PREGKEYCACHE;
typedef struct {
HKEY Key;
BOOL Unicode;
UINT RefCount;
UINT ClosesNeeded;
REGSAM Sam;
UINT KeyStringBytes;
CHAR KeyString[MAX_REGISTRY_KEY];
} WORKITEMA, *PWORKITEMA;
typedef struct {
HKEY Key;
BOOL Unicode;
UINT RefCount;
UINT ClosesNeeded;
REGSAM Sam;
UINT KeyStringBytes;
WCHAR KeyString[MAX_REGISTRY_KEY];
} WORKITEMW, *PWORKITEMW;
GROWLIST g_KeyCache = GROWLIST_INIT;
UINT g_MaxCacheCount = 0;
UINT g_CacheAddPos;
CHAR g_LastParent[MAX_REGISTRY_KEY];
UINT g_LastParentBytes;
UINT g_LastParentUse;
WCHAR g_LastParentW[MAX_REGISTRY_KEY];
UINT g_LastParentBytesW;
UINT g_LastParentUseW;
BOOL
pRemoveItemFromCache (
IN UINT Item
);
//
// Implementation
//
VOID
RegInitializeCache (
IN UINT InitialCacheSize
)
{
if (InitialCacheSize > 64) {
InitialCacheSize = 64;
}
g_MaxCacheCount = InitialCacheSize;
g_CacheAddPos = 0;
g_LastParentUse = 0;
g_LastParentUseW = 0;
}
VOID
RegTerminateCache (
VOID
)
{
UINT u;
UINT count;
count = GrowListGetSize (&g_KeyCache);
for (u = 0 ; u < count ; u++) {
pRemoveItemFromCache (u);
}
FreeGrowList (&g_KeyCache);
g_MaxCacheCount = 0;
g_LastParentUse = 0;
g_LastParentUseW = 0;
}
BOOL
pRemoveItemFromCache (
IN UINT Item
)
{
PREGKEYCACHE cacheItem;
cacheItem = (PREGKEYCACHE) GrowListGetItem (&g_KeyCache, Item);
if (!cacheItem) {
return TRUE;
}
if (cacheItem->RefCount == 0) {
while (cacheItem->ClosesNeeded) {
CloseRegKeyWorker (cacheItem->Key);
cacheItem->ClosesNeeded--;
}
return TRUE;
} else {
return FALSE;
}
}
VOID
RegRecordParentInCacheA (
IN PCSTR KeyString,
IN PCSTR StringEnd
)
{
HKEY key;
UINT byteCount;
CHAR lowerStr[MAX_REGISTRY_KEY];
HKEY rootKey;
UINT end;
if (!g_MaxCacheCount) {
return;
}
if(!KeyString){
MYASSERT(KeyString);
return;
}
if (StringEnd <= KeyString) {
return;
}
byteCount = (UINT) (UINT_PTR) ((PBYTE) StringEnd - (PBYTE) KeyString);
if (byteCount >= (MAX_REGISTRY_KEY * sizeof (CHAR))) {
DEBUGMSG((DBG_WARNING, "RegRecordParentInCacheA: byteCount >= (MAX_REGISTRY_KEY * sizeof (CHAR))"));
return;
}
if (g_LastParentUse && g_LastParentUse < 3 && g_LastParentBytes == byteCount) {
StringCopyABA (lowerStr, KeyString, StringEnd);
CharLowerA (lowerStr);
if (StringMatchA (g_LastParent, lowerStr)) {
g_LastParentUse++;
if (g_LastParentUse == 3) {
//
// Stimulate the cache
//
rootKey = ConvertRootStringToKeyA (lowerStr, &end);
if (rootKey) {
MYASSERT(end <= TcharCountA(lowerStr));
if (lowerStr[end]) {
#ifdef DEBUG
key = OpenRegKeyWorkerA (rootKey, &lowerStr[end], __FILE__, __LINE__);
#else
key = OpenRegKeyWorkerA (rootKey, &lowerStr[end]);
#endif
if (key) {
RegAddKeyToCacheA (lowerStr, key, g_OpenSam);
CloseRegKey (key);
}
}
}
}
return;
}
}
StringCopyABA (g_LastParent, KeyString, StringEnd);
CharLowerA (g_LastParent);
g_LastParentBytes = byteCount;
g_LastParentUse = 1;
}
HKEY
RegGetKeyFromCacheA (
IN PCSTR KeyString,
IN PCSTR KeyEnd, OPTIONAL
IN REGSAM Sam,
IN BOOL IncRefCount
)
{
UINT stringBytes;
PCSTR end;
CHAR lowerStr[MAX_REGISTRY_KEY];
UINT u;
UINT count;
PREGKEYCACHE cacheItem;
if(!KeyString){
MYASSERT(KeyString);
return NULL;
}
count = GrowListGetSize (&g_KeyCache);
if (!count) {
return NULL;
}
if (!KeyEnd) {
end = StackStringCopyA (lowerStr, KeyString);
} else {
if (KeyEnd > (KeyString + MAX_REGISTRY_KEY)) {
KeyEnd = KeyString + MAX_REGISTRY_KEY;
}
end = StringCopyABA (lowerStr, KeyString, KeyEnd);
}
CharLowerA (lowerStr);
stringBytes = (UINT) (UINT_PTR) ((PBYTE) end - (PBYTE) lowerStr);
//
// Scan the cache sequentially (it should be small), and return a match
// if one is found. Stored strings are always in lower case.
//
u = g_CacheAddPos;
do {
cacheItem = (PREGKEYCACHE) GrowListGetItem (&g_KeyCache, u);
if (!cacheItem) {
return NULL;
}
if ((cacheItem->KeyStringBytes == stringBytes) &&
(!cacheItem->Unicode) &&
((cacheItem->Sam & Sam) == Sam) &&
(StringMatchA ((PCSTR) cacheItem->KeyString, lowerStr))
) {
if (IncRefCount) {
cacheItem->RefCount++;
}
return cacheItem->Key;
}
u++;
if (u >= count) {
u = 0;
}
} while (u != g_CacheAddPos);
return NULL;
}
VOID
RegAddKeyToCacheA (
IN PCSTR KeyString,
IN HKEY Key,
IN REGSAM Sam
)
{
PREGKEYCACHE cacheItem;
PREGKEYCACHE lastAddItem;
WORKITEMA workItem;
PCSTR end;
UINT minStructSize;
UINT pos;
UINT count;
UINT u;
if(!KeyString){
MYASSERT(KeyString);
return;
}
if (!g_MaxCacheCount || !Key) {
return;
}
//
// Scan the cache for the existing Key
//
count = GrowListGetSize (&g_KeyCache);
for (u = 0 ; u < count ; u++) {
cacheItem = (PREGKEYCACHE) GrowListGetItem (&g_KeyCache, u);
if (cacheItem->Key == Key) {
cacheItem->RefCount++;
g_CacheAddPos = u;
cacheItem->Sam |= Sam;
if (cacheItem->KeyStringBytes == 0 && *KeyString && !cacheItem->Unicode) {
//
// This key was added before we knew the name. Update the name
// now.
//
DEBUGMSG ((DBG_REG, "Updating empty-named key %s", KeyString));
minStructSize = sizeof (workItem) - sizeof (workItem.KeyString);
CopyMemory (&workItem, cacheItem, minStructSize);
end = StackStringCopyA (workItem.KeyString, KeyString);
CharLowerA (workItem.KeyString);
workItem.KeyStringBytes = (UINT) (UINT_PTR) ((PBYTE) end - (PBYTE) workItem.KeyString);
workItem.ClosesNeeded++;
minStructSize += workItem.KeyStringBytes + sizeof (CHAR);
GrowListSetItem (&g_KeyCache, u, (PBYTE) &workItem, minStructSize);
} else if (*KeyString == 0) {
cacheItem->ClosesNeeded++;
}
return;
}
}
//
// Create the new cache item
//
workItem.Key = Key;
workItem.Unicode = FALSE;
workItem.RefCount = 1;
workItem.ClosesNeeded = 1;
workItem.Sam = Sam;
end = StackStringCopyA (workItem.KeyString, KeyString);
CharLowerA (workItem.KeyString);
workItem.KeyStringBytes = (UINT) (UINT_PTR) ((PBYTE) end - (PBYTE) workItem.KeyString);
minStructSize = sizeof (workItem) - sizeof (workItem.KeyString) + workItem.KeyStringBytes + sizeof (CHAR);
//
// Put work item into grow list
//
if (count < g_MaxCacheCount) {
g_CacheAddPos = count;
GrowListAppend (&g_KeyCache, (PBYTE) &workItem, minStructSize);
} else {
//
// Look for a closed key to discard. If cache is too full, then
// increase the cache size. If the cache size hits 64, then don't
// cache this add.
//
lastAddItem = (PREGKEYCACHE) GrowListGetItem (&g_KeyCache, g_CacheAddPos);
if (lastAddItem) {
for (pos = 0 ; pos < count ; pos++) {
if (pos == g_CacheAddPos) {
continue;
}
cacheItem = (PREGKEYCACHE) GrowListGetItem (&g_KeyCache, pos);
if (cacheItem->KeyStringBytes >= lastAddItem->KeyStringBytes) {
break;
}
if (cacheItem->Unicode) {
continue;
}
if (cacheItem->RefCount) {
continue;
}
if (!StringPrefixA ((PCSTR) lastAddItem->KeyString, (PCSTR) cacheItem->KeyString)) {
break;
}
}
if (pos == count) {
if (g_MaxCacheCount == 64) {
DEBUGMSG ((DBG_REG, "Cache is full of open keys"));
return;
}
g_MaxCacheCount++;
GrowListAppend (&g_KeyCache, (PBYTE) &workItem, minStructSize);
} else {
pRemoveItemFromCache (pos);
GrowListSetItem (&g_KeyCache, pos, (PBYTE) &workItem, minStructSize);
}
g_CacheAddPos = pos;
}
}
}
BOOL
RegDecrementRefCount (
IN HKEY Key
)
{
UINT u;
UINT count;
PREGKEYCACHE cacheItem;
if (!g_MaxCacheCount) {
return FALSE;
}
count = GrowListGetSize (&g_KeyCache);
for (u = 0 ; u < count ; u++) {
cacheItem = (PREGKEYCACHE) GrowListGetItem (&g_KeyCache, u);
if (cacheItem->Key == Key) {
if (cacheItem->RefCount == 0) {
//
// The caller is tried to close the key more times than what
// it was opened.
//
if (cacheItem->Unicode) {
DEBUGMSGW ((
DBG_WHOOPS,
"Reg key %s ref count == 0; trying to close it too many times",
cacheItem->KeyString
));
} else {
DEBUGMSGA ((
DBG_WHOOPS,
"Reg key %s ref count == 0; trying to close it too many times",
cacheItem->KeyString
));
}
} else {
cacheItem->RefCount--;
}
//
// Return TRUE to postpone the close
//
return TRUE;
}
}
return FALSE;
}
VOID
RegRecordParentInCacheW (
IN PCWSTR KeyString,
IN PCWSTR StringEnd
)
{
HKEY key;
UINT byteCount;
WCHAR lowerStr[MAX_REGISTRY_KEY];
HKEY rootKey;
UINT end;
if (!g_MaxCacheCount) {
return;
}
if(!KeyString){
MYASSERT(KeyString);
return;
}
if (StringEnd <= KeyString) {
return;
}
byteCount = (UINT) (UINT_PTR) ((PBYTE) StringEnd - (PBYTE) KeyString);
if (byteCount >= (MAX_REGISTRY_KEY * sizeof (WCHAR))) {
DEBUGMSG((DBG_WARNING, "RegRecordParentInCacheW: byteCount >= (MAX_REGISTRY_KEY * sizeof (WCHAR))"));
return;
}
if (g_LastParentUseW && g_LastParentUseW < 3 && g_LastParentBytesW == byteCount) {
StringCopyABW (lowerStr, KeyString, StringEnd);
CharLowerW (lowerStr);
if (StringMatchW (g_LastParentW, lowerStr)) {
g_LastParentUseW++;
if (g_LastParentUseW == 3) {
//
// Stimulate the cache
//
rootKey = ConvertRootStringToKeyW (lowerStr, &end);
if (rootKey) {
MYASSERT(end <= TcharCountW(lowerStr));
if (lowerStr[end]) {
#ifdef DEBUG
key = OpenRegKeyWorkerW (rootKey, &lowerStr[end], __FILE__, __LINE__);
#else
key = OpenRegKeyWorkerW (rootKey, &lowerStr[end]);
#endif
if (key) {
RegAddKeyToCacheW (lowerStr, key, g_OpenSam);
CloseRegKey (key);
}
}
}
}
return;
}
}
StringCopyABW (g_LastParentW, KeyString, StringEnd);
CharLowerW (g_LastParentW);
g_LastParentBytesW = byteCount;
g_LastParentUseW = 1;
}
HKEY
RegGetKeyFromCacheW (
IN PCWSTR KeyString,
IN PCWSTR KeyEnd, OPTIONAL
IN REGSAM Sam,
IN BOOL IncRefCount
)
{
UINT stringBytes;
PCWSTR end;
WCHAR lowerStr[MAX_REGISTRY_KEY];
UINT u;
UINT count;
PREGKEYCACHE cacheItem;
if(!KeyString){
MYASSERT(KeyString);
return NULL;
}
count = GrowListGetSize (&g_KeyCache);
if (!count) {
return NULL;
}
if (!KeyEnd) {
end = StackStringCopyW (lowerStr, KeyString);
} else {
if (KeyEnd > (KeyString + MAX_REGISTRY_KEY)) {
KeyEnd = KeyString + MAX_REGISTRY_KEY;
}
end = StringCopyABW (lowerStr, KeyString, KeyEnd);
}
CharLowerW (lowerStr);
stringBytes = (UINT) (UINT_PTR) ((PBYTE) end - (PBYTE) lowerStr);
//
// Scan the cache sequentially (it should be small), and return a match
// if one is found. Stored strings are always in lower case.
//
u = g_CacheAddPos;
do {
cacheItem = (PREGKEYCACHE) GrowListGetItem (&g_KeyCache, u);
if (!cacheItem) {
return NULL;
}
if ((cacheItem->KeyStringBytes == stringBytes) &&
(cacheItem->Unicode) &&
((cacheItem->Sam & Sam) == Sam) &&
(StringMatchW ((PCWSTR) cacheItem->KeyString, lowerStr))
) {
if (IncRefCount) {
cacheItem->RefCount++;
}
return cacheItem->Key;
}
u++;
if (u >= count) {
u = 0;
}
} while (u != g_CacheAddPos);
return NULL;
}
VOID
RegAddKeyToCacheW (
IN PCWSTR KeyString,
IN HKEY Key,
IN REGSAM Sam
)
{
PREGKEYCACHE cacheItem;
PREGKEYCACHE lastAddItem;
WORKITEMW workItem;
PCWSTR end;
UINT minStructSize;
UINT pos;
UINT count;
UINT u;
if(!KeyString){
MYASSERT(KeyString);
return;
}
if (!g_MaxCacheCount || !Key) {
return;
}
//
// Scan the cache for the existing Key
//
count = GrowListGetSize (&g_KeyCache);
for (u = 0 ; u < count ; u++) {
cacheItem = (PREGKEYCACHE) GrowListGetItem (&g_KeyCache, u);
if (cacheItem->Key == Key) {
cacheItem->RefCount++;
g_CacheAddPos = u;
cacheItem->Sam |= Sam;
if (cacheItem->KeyStringBytes == 0 && *KeyString && cacheItem->Unicode) {
//
// This key was added before we knew the name. Update the name
// now.
//
minStructSize = sizeof (workItem) - sizeof (workItem.KeyString);
CopyMemory (&workItem, cacheItem, minStructSize);
end = StackStringCopyW (workItem.KeyString, KeyString);
CharLowerW (workItem.KeyString);
workItem.KeyStringBytes = (UINT) (UINT_PTR) ((PBYTE) end - (PBYTE) workItem.KeyString);
workItem.ClosesNeeded++;
minStructSize += workItem.KeyStringBytes + sizeof (WCHAR);
GrowListSetItem (&g_KeyCache, u, (PBYTE) &workItem, minStructSize);
} else if (*KeyString == 0) {
cacheItem->ClosesNeeded++;
}
return;
}
}
//
// Create the new cache item
//
workItem.Key = Key;
workItem.Unicode = TRUE;
workItem.RefCount = 1;
workItem.ClosesNeeded = 1;
workItem.Sam = Sam;
end = StackStringCopyW (workItem.KeyString, KeyString);
CharLowerW (workItem.KeyString);
workItem.KeyStringBytes = (UINT) (UINT_PTR) ((PBYTE) end - (PBYTE) workItem.KeyString);
minStructSize = sizeof (workItem) - sizeof (workItem.KeyString) + workItem.KeyStringBytes + sizeof (WCHAR);
//
// Put work item into grow list
//
if (count < g_MaxCacheCount) {
g_CacheAddPos = count;
GrowListAppend (&g_KeyCache, (PBYTE) &workItem, minStructSize);
} else {
//
// Look for a closed key to discard. If cache is too full, then
// increase the cache size. If the cache size hits 64, then don't
// cache this add.
//
lastAddItem = (PREGKEYCACHE) GrowListGetItem (&g_KeyCache, g_CacheAddPos);
if (lastAddItem) {
for (pos = 0 ; pos < count ; pos++) {
if (pos == g_CacheAddPos) {
continue;
}
cacheItem = (PREGKEYCACHE) GrowListGetItem (&g_KeyCache, pos);
if (cacheItem->KeyStringBytes >= lastAddItem->KeyStringBytes) {
break;
}
if (!cacheItem->Unicode) {
continue;
}
if (cacheItem->RefCount) {
continue;
}
if (!StringPrefixW ((PCWSTR) lastAddItem->KeyString, (PCWSTR) cacheItem->KeyString)) {
break;
}
}
if (pos == count) {
if (g_MaxCacheCount == 64) {
DEBUGMSG ((DBG_REG, "Cache is full of open keys"));
return;
}
g_MaxCacheCount++;
GrowListAppend (&g_KeyCache, (PBYTE) &workItem, minStructSize);
} else {
pRemoveItemFromCache (pos);
GrowListSetItem (&g_KeyCache, pos, (PBYTE) &workItem, minStructSize);
}
g_CacheAddPos = pos;
}
}
}