Windows2000/private/ntos/config/hivechek.c
2020-09-30 17:12:32 +02:00

393 lines
11 KiB
C

/*++
Copyright (c) 1991 Microsoft Corporation
Module Name:
hivechek.c
Abstract:
This module implements consistency checking for hives.
Author:
Bryan M. Willman (bryanwi) 09-Dec-91
Environment:
Revision History:
--*/
#include "cmp.h"
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE,HvCheckHive)
#pragma alloc_text(PAGE,HvCheckBin)
#endif
// debug structures
extern struct {
PHHIVE Hive;
ULONG Status;
ULONG Space;
HCELL_INDEX MapPoint;
PHBIN BinPoint;
} HvCheckHiveDebug;
extern struct {
PHBIN Bin;
ULONG Status;
PHCELL CellPoint;
} HvCheckBinDebug;
#if DBG
ULONG HvHiveChecking=0;
#endif
ULONG
HvCheckHive(
PHHIVE Hive,
PULONG Storage OPTIONAL
)
/*++
Routine Description:
Check the consistency of a hive. Apply CheckBin to bins, make sure
all pointers in the cell map point to correct places.
Arguments:
Hive - supplies a pointer to the hive control structure for the
hive of interest.
Storage - supplies adddress of ULONG to receive size of allocated user data
Return Value:
0 if Hive is OK. Error return indicator if not. Error value
comes from one of the check procedures.
RANGE: 2000 - 2999
--*/
{
HCELL_INDEX p;
ULONG Length;
ULONG localstorage = 0;
PHMAP_ENTRY t;
PHBIN Bin;
ULONG i;
ULONG rc;
PFREE_HBIN FreeBin;
HvCheckHiveDebug.Hive = Hive;
HvCheckHiveDebug.Status = 0;
HvCheckHiveDebug.Space = (ULONG)-1;
HvCheckHiveDebug.MapPoint = HCELL_NIL;
HvCheckHiveDebug.BinPoint = 0;
p = 0;
// one pass for Stable space, one pass for Volatile
for (i = 0; i <= Volatile; i++) {
Length = Hive->Storage[i].Length;
// for each bin in the space
while (p < Length) {
t = HvpGetCellMap(Hive, p);
if (t == NULL) {
KdPrint(("HvCheckHive:"));
KdPrint(("\tBin@:%08lx invalid\n", Bin));
HvCheckHiveDebug.Status = 2005;
HvCheckHiveDebug.Space = i;
HvCheckHiveDebug.MapPoint = p;
return 2005;
}
if ((t->BinAddress & HMAP_DISCARDABLE) == 0) {
Bin = (PHBIN)((t->BinAddress) & HMAP_BASE);
// bin header valid?
if ( (Bin->Size > Length) ||
(Bin->Signature != HBIN_SIGNATURE) ||
(Bin->FileOffset != p)
)
{
KdPrint(("HvCheckHive:"));
KdPrint(("\tBin@:%08lx invalid\n", Bin));
HvCheckHiveDebug.Status = 2010;
HvCheckHiveDebug.Space = i;
HvCheckHiveDebug.MapPoint = p;
HvCheckHiveDebug.BinPoint = Bin;
return 2010;
}
// structure inside the bin valid?
rc = HvCheckBin(Hive, Bin, &localstorage);
if (rc != 0) {
HvCheckHiveDebug.Status = rc;
HvCheckHiveDebug.Space = i;
HvCheckHiveDebug.MapPoint = p;
HvCheckHiveDebug.BinPoint = Bin;
return rc;
}
p = (ULONG)p + Bin->Size;
} else {
// Bin is not present, skip it and advance to the next one.
FreeBin = (PFREE_HBIN)t->BlockAddress;
p+=FreeBin->Size;
}
}
p = 0x80000000; // Beginning of Volatile space
}
if (ARGUMENT_PRESENT(Storage)) {
*Storage = localstorage;
}
return 0;
}
ULONG
HvCheckBin(
PHHIVE Hive,
PHBIN Bin,
PULONG Storage
)
/*++
Routine Description:
Step through all of the cells in the bin. Make sure that
they are consistent with each other, and with the bin header.
Arguments:
Hive - pointer to the hive control structure
Bin - pointer to bin to check
Storage - pointer to a ulong to get allocated user data size
Return Value:
0 if Bin is OK. Number of test in procedure that failed if not.
RANGE: 1 - 1999
--*/
{
PHCELL p;
PHCELL np;
PHCELL lp;
ULONG freespace = 0L;
ULONG allocated = 0L;
ULONG userallocated = 0L;
HvCheckBinDebug.Bin = Bin;
HvCheckBinDebug.Status = 0;
HvCheckBinDebug.CellPoint = 0;
// Scan all the cells in the bin, total free and allocated, check
// for impossible pointers.
p = (PHCELL)((PUCHAR)Bin + sizeof(HBIN));
lp = p;
// DRAGOS:
// The way allocated and freespace are computed implies the following invariants:
// 1. allocated + freespace = p + p->Size - (Bin + sizeof(HBIN)). This is because p->Size is added either to allocated or to freespace.
// So, assuming that allocated > Bin->Size , then
// ==> p + p->Size - (Bin + sizeof(HBIN)) > Bin->Size.
// ==> p + p->Size > Bin + Bin->Size + sizeof(HBIN)
// ==> p + p->Size > Bin + Bin->Size
// This proves that the test "NeverFail 1" (see bellow) will never fail, because when something is wrong, the test above it (namely "Fail 1") will fail
// and the function will exit.
// The same logic applies to the test "NeverFail 2", so it can be removed also.
// 2. The new value of p is always calculated as p = p + p->Size. By the time this is done, the new value of p (ie. p + p->Size) is already checked against
// Bin + Bin->Size (see tests "Fail 1" and "Fail 2"). So, if p > Bin + Bin->Size, either "Fail 1" or "Fail 2" will fail before asigning the new bogus value
// to p. Therefore, the only possible path to exit the while loop (except a return 20 or return 40), is when p == Bin + Bin->Size.
// ==> test "NeverFail 3" can be removed as it will never fail !
// 3. Considering 1 (where p + p->Size became p)
// ==> allocated + freespace = p - (Bin + sizeof(HBIN))
// But, Considering 2 (above), when the while loop exits, p = Bin + Bin->Size
// ==> allocated + freespace = Bin + Bin->Size - (Bin + sizeof(HBIN))
// ==> allocated + freespace + sizeof(HBIN) = Bin->Size
// This proves that test "NeverFail 4" (see bellow) will never fail as the expresion tested is always true (if the flow of execution reaches the test point).
while (p < (PHCELL)((PUCHAR)Bin + Bin->Size)) {
// Check last pointer
if (USE_OLD_CELL(Hive)) {
if (lp == p) {
if (p->u.OldCell.Last != HBIN_NIL) {
KdPrint(("HvCheckBin 20: First cell has wrong last pointer\n"));
KdPrint(("Bin = %08lx\n", Bin));
HvCheckBinDebug.Status = 20;
HvCheckBinDebug.CellPoint = p;
return 20;
}
} else {
if ((PHCELL)(p->u.OldCell.Last + (PUCHAR)Bin) != lp) {
KdPrint(("HvCheckBin 30: incorrect last pointer\n"));
KdPrint(("Bin = %08lx\n", Bin));
KdPrint(("p = %08lx\n", (ULONG_PTR)p));
HvCheckBinDebug.Status = 30;
HvCheckBinDebug.CellPoint = p;
return 30;
}
}
}
// Check size
if (p->Size < 0) {
// allocated cell
// DRAGOS: Fail 1
// This test will alway fail prior to the failure of the bellow test
if ( ((ULONG)(p->Size * -1) > Bin->Size) ||
( (PHCELL)((p->Size * -1) + (PUCHAR)p) >
(PHCELL)((PUCHAR)Bin + Bin->Size) )
)
{
KdPrint(("HvCheckBin 40: impossible allocation\n"));
KdPrint(("Bin = %08lx\n", Bin));
HvCheckBinDebug.Status = 40;
HvCheckBinDebug.CellPoint = p;
return 40;
}
allocated += (p->Size * -1);
if (USE_OLD_CELL(Hive)) {
userallocated += (p->Size * -1) - FIELD_OFFSET(HCELL, u.OldCell.u.UserData);
} else {
userallocated += (p->Size * -1) - FIELD_OFFSET(HCELL, u.NewCell.u.UserData);
}
// DRAGOS: NeverFail 1
// This test will never fail. If a size is wrong the above test (Fail 1)will fail. We can remove this test (it's useless).
if (allocated > Bin->Size) {
KdPrint(("HvCheckBin 50: allocated exceeds available\n"));
KdPrint(("Bin = %08lx\n", Bin));
HvCheckBinDebug.Status = 50;
HvCheckBinDebug.CellPoint = p;
return 50;
}
np = (PHCELL)((PUCHAR)p + (p->Size * -1));
} else {
// free cell
// DRAGOS: Fail 2
// This test will alway fail prior to the failure of the bellow test
if ( ((ULONG)p->Size > Bin->Size) ||
( (PHCELL)(p->Size + (PUCHAR)p) >
(PHCELL)((PUCHAR)Bin + Bin->Size) ) ||
(p->Size == 0) )
{
KdPrint(("HvCheckBin 60: impossible free block\n"));
KdPrint(("Bin = %08lx\n", Bin));
HvCheckBinDebug.Status = 60;
HvCheckBinDebug.CellPoint = p;
return 60;
}
freespace = freespace + p->Size;
// DRAGOS: NeverFail 2
// This test will never fail. If a size is wrong the above test (Fail 2) will fail. We can remove this test (it's useless).
if (freespace > Bin->Size) {
KdPrint(("HvCheckBin 70: free exceeds available\n"));
KdPrint(("Bin = %08lx\n", Bin));
HvCheckBinDebug.Status = 70;
HvCheckBinDebug.CellPoint = p;
return 70;
}
np = (PHCELL)((PUCHAR)p + p->Size);
}
lp = p;
p = np;
}
// DRAGOS: NeverFail 4
// This test never fails. If the while loop exits, the condition tested here is always true!!!
// We can remove this test (it's useless)
if ((freespace + allocated + sizeof(HBIN)) != Bin->Size) {
KdPrint(("HvCheckBin 995: sizes do not add up\n"));
KdPrint(("Bin = %08lx\n", Bin));
KdPrint(("freespace = %08lx ", freespace));
KdPrint(("allocated = %08lx ", allocated));
KdPrint(("size = %08lx\n", Bin->Size));
HvCheckBinDebug.Status = 995;
return 995;
}
// DRAGOS: NeverFail 3
// This test never fails. The only way out of the while loop is when p == Bin + Bin->Size !!!!!!!
// We can remove this test (it's useless)
if (p != (PHCELL)((PUCHAR)Bin + Bin->Size)) {
KdPrint(("HvCheckBin 1000: last cell points off the end\n"));
KdPrint(("Bin = %08lx\n", Bin));
HvCheckBinDebug.Status = 1000;
return 1000;
}
if (ARGUMENT_PRESENT(Storage)) {
*Storage += userallocated;
}
return 0;
}