NT4/private/windows/base/advapi/digsig/softpub/util.cpp
2020-09-30 17:12:29 +02:00

958 lines
28 KiB
C++

//
// util.cpp
//
// Miscellaneous support utilities
//
#include "stdpch.h"
#include "common.h"
//////
LPWSTR CopyTaskMem(LPCWSTR wsz)
{
if (wsz)
{
int cch = lstrlenW(wsz) + 1;
int cb = cch * sizeof(WCHAR);
LPWSTR wszOut = (LPWSTR)CoTaskMemAlloc(cb);
if (wszOut)
{
memcpy(wszOut, wsz, cb);
}
return wszOut;
}
else
return NULL;
}
//////
BOOL AnyMatch(CERTIFICATENAMES& n1, CERTIFICATENAMES& n2)
// Answer as to whether any of the names in n2 match those in n1
{
if ((n1.flags&CERTIFICATENAME_DIGEST) && (n2.flags&CERTIFICATENAME_DIGEST))
{
if (memcmp(&n1.digest, &n2.digest, sizeof(n1.digest)) == 0)
return TRUE;
}
if ((n1.flags&CERTIFICATENAME_ISSUERSERIAL) && (n2.flags&CERTIFICATENAME_ISSUERSERIAL))
{
if (IsEqual(n1.issuerSerial.issuerName, n2.issuerSerial.issuerName) &&
IsEqual(n1.issuerSerial.serialNumber, n2.issuerSerial.serialNumber))
return TRUE;
}
if ((n1.flags&CERTIFICATENAME_SUBJECT) && (n2.flags&CERTIFICATENAME_SUBJECT))
{
if (IsEqual(n1.subject, n2.subject))
return TRUE;
}
if ((n1.flags&CERTIFICATENAME_ISSUER) && (n2.flags&CERTIFICATENAME_ISSUER))
{
if (IsEqual(n1.issuer, n2.issuer))
return TRUE;
}
return FALSE;
}
/////
HRESULT HError ()
{
DWORD dw = GetLastError ();
HRESULT hr;
if ( dw <= 0xFFFF )
hr = HRESULT_FROM_WIN32 ( dw );
else
hr = dw;
if ( ! FAILED ( hr ) )
{
// somebody failed a call without properly setting an error condition
hr = E_UNEXPECTED;
}
return hr;
}
/////
void FreeNames
(
CERTIFICATENAMES* names,
DWORD dwKeep
)
{
if ( (names->flags & CERTIFICATENAME_ISSUERSERIAL)
&&!(dwKeep & CERTIFICATENAME_ISSUERSERIAL) )
{
CoTaskMemFree ( names->issuerSerial.issuerName.pBlobData );
CoTaskMemFree ( names->issuerSerial.serialNumber.pBlobData );
names->flags &= ~CERTIFICATENAME_ISSUERSERIAL;
}
if ( (names->flags & CERTIFICATENAME_SUBJECT)
&&!(dwKeep & CERTIFICATENAME_SUBJECT) )
{
CoTaskMemFree ( names->subject.pBlobData );
names->flags &= ~CERTIFICATENAME_SUBJECT;
}
if ( (names->flags & CERTIFICATENAME_ISSUER)
&&!(dwKeep & CERTIFICATENAME_ISSUER) )
{
CoTaskMemFree ( names->issuer.pBlobData );
names->flags &= ~CERTIFICATENAME_ISSUER;
}
if ( (names->flags & CERTIFICATENAME_DIGEST)
&&!(dwKeep & CERTIFICATENAME_DIGEST) )
{
names->flags &= ~CERTIFICATENAME_DIGEST;
}
}
/////
BOOL IsEqual
(
BLOB& b1,
BLOB& b2
)
{
return b1.cbSize == b2.cbSize &&
memcmp ( b1.pBlobData, b2.pBlobData, b1.cbSize ) == 0;
}
/////
BOOL IsIncludedIn(OSIOBJECTIDLIST* plist, const OSIOBJECTID* pidHim)
// Answer as to whether the indicated pid is included in the indicated list
{
for (ULONG iid = 0; iid < plist->cid; iid++)
{
OSIOBJECTID* pid = (OSIOBJECTID*)( (BYTE*)plist + plist->rgwOffset[iid] );
if (IsEqual(pid, pidHim))
return TRUE;
}
return FALSE;
}
////////////////////////////////////////////////////////////////
//
// Glue class that controls and manages our access to the
// digsig library.
//
CDigSig* pdigsig = NULL; // Global data; automatically initialized to zero
CImagehlp* pimagehlp = NULL;
void ReleaseGlobals()
{
if (pdigsig)
{
delete pdigsig;
pdigsig = NULL;
}
if (pimagehlp)
{
delete pimagehlp;
pimagehlp = NULL;
}
}
void InitGlobals()
{
pdigsig = new CDigSig;
pimagehlp = new CImagehlp;
}
/////////////////////////////////////////////////////////////////////////////
//
// The instance handle of this DLL
//
HINSTANCE hinst;
extern "C"
BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD dwReason, LPVOID)
//
// We implement so we can remember our instance handle and so
// we can dynaload and free digsig on demand.
//
{
if (dwReason == DLL_PROCESS_ATTACH)
{
hinst = hInstance;
InitGlobals();
}
else if (dwReason == DLL_PROCESS_DETACH)
{
ReleaseGlobals();
}
return TRUE;
}
////////////////////////////////////////////////////////////////
void CDigSig::Load()
{
if (m_hinstDigsig==NULL)
{
m_hinstDigsig = (HMODULE)LoadLibrary("DIGSIG");
}
}
void CDigSig::Free()
{
if (m_hinstDigsig)
FreeLibrary(m_hinstDigsig);
m_hinstDigsig = NULL;
m_CreatePkcs7SignedData = NULL;
m_CreatePkcs10 = NULL;
m_CreateX509 = NULL;
m_CreateX500Name = NULL;
m_OpenCertificateStore = NULL;
m_CreateCABSigner = NULL;
m_CreateMsDefKeyPair = NULL;
}
BOOL CDigSig::Invoke(LPCSTR szEntry, PFN& proc, IUnknown* punkOuter, REFIID iid, LPVOID*ppv)
//
// Invoke the entry point of the given name, caching the result in the indicated variable 'proc'.
// The entry point must have signature
// BOOL (*)(NULL, REFIID, LPVOID*)
//
{
if (proc==NULL)
{
Load();
if (m_hinstDigsig)
{
proc = (PFN)GetProcAddress(m_hinstDigsig, szEntry);
}
}
if (proc)
return (proc)(punkOuter, iid, ppv);
else
{
SetLastError(ERROR_PROC_NOT_FOUND);
return FALSE;
}
}
BOOL DIGSIGAPI CDigSig::CreatePkcs7SignedData(IUnknown* punkOuter, REFIID iid, LPVOID*ppv)
{
return Invoke("CreatePkcs7SignedData", m_CreatePkcs7SignedData, punkOuter, iid, ppv);
}
BOOL DIGSIGAPI CDigSig::CreatePkcs10(IUnknown* punkOuter, REFIID iid, LPVOID*ppv)
{
return Invoke("CreatePkcs10", m_CreatePkcs10, punkOuter, iid, ppv);
}
BOOL DIGSIGAPI CDigSig::CreateX509(IUnknown* punkOuter, REFIID iid, LPVOID*ppv)
{
return Invoke("CreateX509", m_CreateX509, punkOuter, iid, ppv);
}
BOOL DIGSIGAPI CDigSig::CreateX500Name(IUnknown* punkOuter, REFIID iid, LPVOID*ppv)
{
return Invoke("CreateX500Name", m_CreateX500Name, punkOuter, iid, ppv);
}
BOOL DIGSIGAPI CDigSig::OpenCertificateStore(IUnknown* punkOuter, REFIID iid, LPVOID*ppv)
{
return Invoke("OpenCertificateStore", m_OpenCertificateStore, punkOuter, iid, ppv);
}
BOOL DIGSIGAPI CDigSig::CreateCABSigner(IUnknown* punkOuter, REFIID iid, LPVOID*ppv)
{
return Invoke("CreateCABSigner", m_CreateCABSigner, punkOuter, iid, ppv);
}
BOOL DIGSIGAPI CDigSig::CreateMsDefKeyPair(IUnknown* punkOuter, REFIID iid, LPVOID*ppv)
{
return Invoke("CreateMsDefKeyPair", m_CreateMsDefKeyPair, punkOuter, iid, ppv);
}
/////////////////////////////////////////////////////
void CImagehlp::Load()
{
if (m_hinstImagehlp==NULL)
{
m_hinstImagehlp = (HMODULE)LoadLibrary("IMAGEHLP");
}
}
void CImagehlp::Free()
{
if (m_hinstImagehlp)
FreeLibrary(m_hinstImagehlp);
m_hinstImagehlp = NULL;
m_ImageGetDigestStream = NULL;
m_ImageAddCertificate = NULL;
m_ImageRemoveCertificate = NULL;
m_ImageEnumerateCertificates= NULL;
m_ImageGetCertificateData = NULL;
m_ImageGetCertificateHeader = NULL;
}
void CImagehlp::Load(LPCSTR szEntry, LPVOID* pproc)
{
if (*pproc==NULL)
{
Load();
if (m_hinstImagehlp)
{
*pproc = GetProcAddress(m_hinstImagehlp, szEntry);
}
}
if (!*pproc)
SetLastError(ERROR_PROC_NOT_FOUND);
}
//////////
BOOL
WINAPI
CImagehlp::ImageGetDigestStream(
IN HANDLE FileHandle,
IN DWORD DigestLevel,
IN DIGEST_FUNCTION DigestFunction,
IN DIGEST_HANDLE DigestHandle
) {
Load("ImageGetDigestStream", (LPVOID*)&m_ImageGetDigestStream);
if (m_ImageGetDigestStream)
return (m_ImageGetDigestStream)(FileHandle, DigestLevel, DigestFunction, DigestHandle);
else
return FALSE;
}
BOOL
WINAPI
CImagehlp::ImageAddCertificate(
IN HANDLE FileHandle,
IN LPWIN_CERTIFICATE Certificate,
OUT PDWORD Index
) {
Load("ImageAddCertificate", (LPVOID*)&m_ImageAddCertificate);
if (m_ImageAddCertificate)
return (m_ImageAddCertificate)(FileHandle, Certificate, Index);
else
return FALSE;
}
BOOL
WINAPI
CImagehlp::ImageRemoveCertificate(
IN HANDLE FileHandle,
IN DWORD Index
) {
Load("ImageRemoveCertificate", (LPVOID*)&m_ImageRemoveCertificate);
if (m_ImageRemoveCertificate)
return (m_ImageRemoveCertificate)(FileHandle, Index);
else
return FALSE;
}
BOOL
WINAPI
CImagehlp::ImageEnumerateCertificates(
IN HANDLE FileHandle,
IN WORD TypeFilter,
OUT PDWORD CertificateCount,
IN OUT PDWORD Indices OPTIONAL,
IN OUT DWORD IndexCount OPTIONAL
) {
Load("ImageEnumerateCertificates", (LPVOID*)&m_ImageEnumerateCertificates);
if (m_ImageEnumerateCertificates)
return (m_ImageEnumerateCertificates)(FileHandle, TypeFilter, CertificateCount, Indices, IndexCount);
else
return FALSE;
}
BOOL
WINAPI
CImagehlp::ImageGetCertificateData(
IN HANDLE FileHandle,
IN DWORD CertificateIndex,
OUT LPWIN_CERTIFICATE Certificate,
IN OUT PDWORD RequiredLength
) {
Load("ImageGetCertificateData", (LPVOID*)&m_ImageGetCertificateData);
if (m_ImageGetCertificateData)
return (m_ImageGetCertificateData)(FileHandle, CertificateIndex, Certificate, RequiredLength);
else
return FALSE;
}
BOOL
WINAPI
CImagehlp::ImageGetCertificateHeader(
IN HANDLE FileHandle,
IN DWORD CertificateIndex,
IN OUT LPWIN_CERTIFICATE Certificateheader
) {
Load("ImageGetCertificateHeader", (LPVOID*)&m_ImageGetCertificateHeader);
if (m_ImageGetCertificateHeader)
return (m_ImageGetCertificateHeader)(FileHandle, CertificateIndex, Certificateheader);
else
return FALSE;
}
////////////////////////////////////////////////////////////////////////
//
// Functions that reduce our dependence on the C runtime
//
////////////////////////////////////////////////////////////////////////
//
extern "C" int __cdecl _purecall(void)
{
return 0;
}
////////////////////////////////////////////////////////////////////////
//
// QSort implementation
//
////////////////////////////////////////////////////////////////////////
/* prototypes for local routines */
static void __cdecl shortsort(char *lo, char *hi, unsigned width,
int (__cdecl *comp)(const void *, const void *));
static void __cdecl swap(char *p, char *q, unsigned int width);
/* this parameter defines the cutoff between using quick sort and
insertion sort for arrays; arrays with lengths shorter or equal to the
below value use insertion sort */
#define CUTOFF 8 /* testing shows that this is good value */
/***
*qsort(base, num, wid, comp) - quicksort function for sorting arrays
*
*Purpose:
* quicksort the array of elements
* side effects: sorts in place
*
*Entry:
* char *base = pointer to base of array
* unsigned num = number of elements in the array
* unsigned width = width in bytes of each array element
* int (*comp)() = pointer to function returning analog of strcmp for
* strings, but supplied by user for comparing the array elements.
* it accepts 2 pointers to elements and returns neg if 1<2, 0 if
* 1=2, pos if 1>2.
*
*Exit:
* returns void
*
*Exceptions:
*
*******************************************************************************/
/* sort the array between lo and hi (inclusive) */
void __cdecl qsort (
void *base,
unsigned num,
unsigned width,
int (__cdecl *comp)(const void *, const void *)
)
{
char *lo, *hi; /* ends of sub-array currently sorting */
char *mid; /* points to middle of subarray */
char *loguy, *higuy; /* traveling pointers for partition step */
unsigned size; /* size of the sub-array */
char *lostk[30], *histk[30];
int stkptr; /* stack for saving sub-array to be processed */
/* Note: the number of stack entries required is no more than
1 + log2(size), so 30 is sufficient for any array */
if (num < 2 || width == 0)
return; /* nothing to do */
stkptr = 0; /* initialize stack */
lo = (char*)base;
hi = (char *)base + width * (num-1); /* initialize limits */
/* this entry point is for pseudo-recursion calling: setting
lo and hi and jumping to here is like recursion, but stkptr is
prserved, locals aren't, so we preserve stuff on the stack */
recurse:
size = (hi - lo) / width + 1; /* number of el's to sort */
/* below a certain size, it is faster to use a O(n^2) sorting method */
if (size <= CUTOFF) {
shortsort(lo, hi, width, comp);
}
else {
/* First we pick a partititioning element. The efficiency of the
algorithm demands that we find one that is approximately the
median of the values, but also that we select one fast. Using
the first one produces bad performace if the array is already
sorted, so we use the middle one, which would require a very
wierdly arranged array for worst case performance. Testing shows
that a median-of-three algorithm does not, in general, increase
performance. */
mid = lo + (size / 2) * width; /* find middle element */
swap(mid, lo, width); /* swap it to beginning of array */
/* We now wish to partition the array into three pieces, one
consisiting of elements <= partition element, one of elements
equal to the parition element, and one of element >= to it. This
is done below; comments indicate conditions established at every
step. */
loguy = lo;
higuy = hi + width;
/* Note that higuy decreases and loguy increases on every iteration,
so loop must terminate. */
for (;;) {
/* lo <= loguy < hi, lo < higuy <= hi + 1,
A[i] <= A[lo] for lo <= i <= loguy,
A[i] >= A[lo] for higuy <= i <= hi */
do {
loguy += width;
} while (loguy <= hi && comp(loguy, lo) <= 0);
/* lo < loguy <= hi+1, A[i] <= A[lo] for lo <= i < loguy,
either loguy > hi or A[loguy] > A[lo] */
do {
higuy -= width;
} while (higuy > lo && comp(higuy, lo) >= 0);
/* lo-1 <= higuy <= hi, A[i] >= A[lo] for higuy < i <= hi,
either higuy <= lo or A[higuy] < A[lo] */
if (higuy < loguy)
break;
/* if loguy > hi or higuy <= lo, then we would have exited, so
A[loguy] > A[lo], A[higuy] < A[lo],
loguy < hi, highy > lo */
swap(loguy, higuy, width);
/* A[loguy] < A[lo], A[higuy] > A[lo]; so condition at top
of loop is re-established */
}
/* A[i] >= A[lo] for higuy < i <= hi,
A[i] <= A[lo] for lo <= i < loguy,
higuy < loguy, lo <= higuy <= hi
implying:
A[i] >= A[lo] for loguy <= i <= hi,
A[i] <= A[lo] for lo <= i <= higuy,
A[i] = A[lo] for higuy < i < loguy */
swap(lo, higuy, width); /* put partition element in place */
/* OK, now we have the following:
A[i] >= A[higuy] for loguy <= i <= hi,
A[i] <= A[higuy] for lo <= i < higuy
A[i] = A[lo] for higuy <= i < loguy */
/* We've finished the partition, now we want to sort the subarrays
[lo, higuy-1] and [loguy, hi].
We do the smaller one first to minimize stack usage.
We only sort arrays of length 2 or more.*/
if ( higuy - 1 - lo >= hi - loguy ) {
if (lo + width < higuy) {
lostk[stkptr] = lo;
histk[stkptr] = higuy - width;
++stkptr;
} /* save big recursion for later */
if (loguy < hi) {
lo = loguy;
goto recurse; /* do small recursion */
}
}
else {
if (loguy < hi) {
lostk[stkptr] = loguy;
histk[stkptr] = hi;
++stkptr; /* save big recursion for later */
}
if (lo + width < higuy) {
hi = higuy - width;
goto recurse; /* do small recursion */
}
}
}
/* We have sorted the array, except for any pending sorts on the stack.
Check if there are any, and do them. */
--stkptr;
if (stkptr >= 0) {
lo = lostk[stkptr];
hi = histk[stkptr];
goto recurse; /* pop subarray from stack */
}
else
return; /* all subarrays done */
}
/***
*shortsort(hi, lo, width, comp) - insertion sort for sorting short arrays
*
*Purpose:
* sorts the sub-array of elements between lo and hi (inclusive)
* side effects: sorts in place
* assumes that lo < hi
*
*Entry:
* char *lo = pointer to low element to sort
* char *hi = pointer to high element to sort
* unsigned width = width in bytes of each array element
* int (*comp)() = pointer to function returning analog of strcmp for
* strings, but supplied by user for comparing the array elements.
* it accepts 2 pointers to elements and returns neg if 1<2, 0 if
* 1=2, pos if 1>2.
*
*Exit:
* returns void
*
*Exceptions:
*
*******************************************************************************/
static void __cdecl shortsort (
char *lo,
char *hi,
unsigned width,
int (__cdecl *comp)(const void *, const void *)
)
{
char *p, *max;
/* Note: in assertions below, i and j are alway inside original bound of
array to sort. */
while (hi > lo) {
/* A[i] <= A[j] for i <= j, j > hi */
max = lo;
for (p = lo+width; p <= hi; p += width) {
/* A[i] <= A[max] for lo <= i < p */
if (comp(p, max) > 0) {
max = p;
}
/* A[i] <= A[max] for lo <= i <= p */
}
/* A[i] <= A[max] for lo <= i <= hi */
swap(max, hi, width);
/* A[i] <= A[hi] for i <= hi, so A[i] <= A[j] for i <= j, j >= hi */
hi -= width;
/* A[i] <= A[j] for i <= j, j > hi, loop top condition established */
}
/* A[i] <= A[j] for i <= j, j > lo, which implies A[i] <= A[j] for i < j,
so array is sorted */
}
/***
*swap(a, b, width) - swap two elements
*
*Purpose:
* swaps the two array elements of size width
*
*Entry:
* char *a, *b = pointer to two elements to swap
* unsigned width = width in bytes of each array element
*
*Exit:
* returns void
*
*Exceptions:
*
*******************************************************************************/
static void __cdecl swap (
char *a,
char *b,
unsigned width
)
{
char tmp;
if ( a != b )
/* Do the swap one character at a time to avoid potential alignment
problems. */
while ( width-- ) {
tmp = *a;
*a++ = *b;
*b++ = tmp;
}
}
////////////////////////////////////////////////////////////////////////
//
// atol implementation
//
////////////////////////////////////////////////////////////////////////
#undef isspace
#undef isdigit
inline BOOL __cdecl isdigit(int ch)
{
return (ch >= '0') && (ch <= '9');
}
inline BOOL __cdecl isspace(int ch)
{
return (ch == ' ') || (ch == 13) || (ch == 10) || (ch == 9);
}
long __cdecl atol(const char *nptr)
{
int c; /* current char */
long total; /* current total */
int sign; /* if '-', then negative, otherwise positive */
/* skip whitespace */
while ( isspace((int)(unsigned char)*nptr) )
++nptr;
c = (int)(unsigned char)*nptr++;
sign = c; /* save sign indication */
if (c == '-' || c == '+')
c = (int)(unsigned char)*nptr++; /* skip sign */
total = 0;
while (isdigit(c)) {
total = 10 * total + (c - '0'); /* accumulate digit */
c = (int)(unsigned char)*nptr++; /* get next char */
}
if (sign == '-')
return -total;
else
return total; /* return result, negated if necessary */
}
////////////////////////////////////////////////////////////////////////
//
// ltoa implementation
//
////////////////////////////////////////////////////////////////////////
void __cdecl xtoa (
unsigned long val,
char *buf,
unsigned radix,
int is_neg
)
{
char *p; /* pointer to traverse string */
char *firstdig; /* pointer to first digit */
char temp; /* temp char */
unsigned digval; /* value of digit */
p = buf;
if (is_neg) {
/* negative, so output '-' and negate */
*p++ = '-';
val = (unsigned long)(-(long)val);
}
firstdig = p; /* save pointer to first digit */
do {
digval = (unsigned) (val % radix);
val /= radix; /* get next digit */
/* convert to ascii and store */
if (digval > 9)
*p++ = (char) (digval - 10 + 'a'); /* a letter */
else
*p++ = (char) (digval + '0'); /* a digit */
} while (val > 0);
/* We now have the digit of the number in the buffer, but in reverse
order. Thus we reverse them now. */
*p-- = '\0'; /* terminate string; p points to last digit */
do {
temp = *p;
*p = *firstdig;
*firstdig = temp; /* swap *p and *firstdig */
--p;
++firstdig; /* advance to next two digits */
} while (firstdig < p); /* repeat until halfway */
}
/* Actual functions just call conversion helper with neg flag set correctly,
and return pointer to buffer. */
char * __cdecl _ltoa (
long val,
char *buf,
int radix
)
{
xtoa((unsigned long)val, buf, radix, (radix == 10 && val < 0));
return buf;
}
////////////////////////////////////////////////////////////////////////
//
// _alloca_probe implementation
//
////////////////////////////////////////////////////////////////////////
#ifdef _M_IX86
/*
_PAGESIZE_ equ 1000h
;***
;_chkstk - check stack upon procedure entry
;
;Purpose:
; Provide stack checking on procedure entry. Method is to simply probe
; each page of memory required for the stack in descending order. This
; causes the necessary pages of memory to be allocated via the guard
; page scheme, if possible. In the event of failure, the OS raises the
; _XCPT_UNABLE_TO_GROW_STACK exception.
;
; NOTE: Currently, the (EAX < _PAGESIZE_) code path falls through
; to the "lastpage" label of the (EAX >= _PAGESIZE_) code path. This
; is small; a minor speed optimization would be to special case
; this up top. This would avoid the painful save/restore of
; ecx and would shorten the code path by 4-6 instructions.
;
;Entry:
; EAX = size of local frame
;
;Exit:
; ESP = new stackframe, if successful
;
;Uses:
; EAX
;
;Exceptions:
; _XCPT_GUARD_PAGE_VIOLATION - May be raised on a page probe. NEVER TRAP
; THIS!!!! It is used by the OS to grow the
; stack on demand.
; _XCPT_UNABLE_TO_GROW_STACK - The stack cannot be grown. More precisely,
; the attempt by the OS memory manager to
; allocate another guard page in response
; to a _XCPT_GUARD_PAGE_VIOLATION has
; failed.
;
;*******************************************************************************
labelP _alloca_probe, PUBLIC
labelP _chkstk, PUBLIC
push ecx ; save ecx
cmp eax,_PAGESIZE_ ; more than one page requested?
lea ecx,[esp] + 8 ; compute new stack pointer in ecx
; correct for return address and
; saved ecx
jb short lastpage ; no
probepages:
sub ecx,_PAGESIZE_ ; yes, move down a page
sub eax,_PAGESIZE_ ; adjust request and...
test dword ptr [ecx],eax ; ...probe it
cmp eax,_PAGESIZE_ ; more than one page requested?
jae short probepages ; no
lastpage:
sub ecx,eax ; move stack down by eax
mov eax,esp ; save current tos and do a...
test dword ptr [ecx],eax ; ...probe in case a page was crossed
mov esp,ecx ; set the new stack pointer
mov ecx,dword ptr [eax] ; recover ecx
mov eax,dword ptr [eax + 4] ; recover return address
push eax ; prepare return address
; ...probe in case a page was crossed
ret
end
*/
#define _PAGESIZE_ 0x1000
extern "C" void __cdecl _alloca_probe();
extern "C" __declspec(naked) void __cdecl _chkstk()
{
_asm
{
jmp _alloca_probe
}
}
extern "C" __declspec(naked) void __cdecl _alloca_probe()
{
_asm
{
push ecx //; save ecx
cmp eax,_PAGESIZE_ //; more than one page requested?
lea ecx,[esp] + 8 //; compute new stack pointer in ecx
//; correct for return address and
//; saved ecx
jb short lastpage //; no
probepages:
sub ecx,_PAGESIZE_ //; yes, move down a page
sub eax,_PAGESIZE_ //; adjust request and...
test dword ptr [ecx],eax //; ...probe it
cmp eax,_PAGESIZE_ //; more than one page requested?
jae short probepages //; no
lastpage:
sub ecx,eax //; move stack down by eax
mov eax,esp //; save current tos and do a...
test dword ptr [ecx],eax //; ...probe in case a page was crossed
mov esp,ecx //; set the new stack pointer
mov ecx,dword ptr [eax] //; recover ecx
mov eax,dword ptr [eax + 4] //; recover return address
push eax //; prepare return address
//; ...probe in case a page was crossed
ret
}
}
#endif // x86-only