C_GetMechanismList
CK_DEFINE_FUNCTION(CK_RV, C_GetMechanismList)(
CK_SLOT_ID slotID,
CK_MECHANISM_TYPE_PTR pMechanismList,
CK_ULONG_PTR pulCount
);
C_GetMechanismList is used to obtain a list of mechanism types supported by a token. SlotID is the ID of the token’s slot; pulCount points to the location that receives the number of mechanisms.
There are two ways for an application to call C_GetMechanismList:
If pMechanismList is NULL_PTR, then all that C_GetMechanismList does is return (in *pulCount) the number of mechanisms, without actually returning a list of mechanisms. The contents of *pulCount on entry to C_GetMechanismList has no meaning in this case, and the call returns the value CKR_OK.
If pMechanismList is not NULL_PTR, then *pulCount must contain the size (in terms of CK_MECHANISM_TYPE elements) of the buffer pointed to by pMechanismList. If that buffer is large enough to hold the list of mechanisms, then the list is returned in it, and CKR_OK is returned. If not, then the call to C_GetMechanismList returns the value CKR_BUFFER_TOO_SMALL. In either case, the value *pulCount is set to hold the number of mechanisms.
Because C_GetMechanismList does not allocate any space of its own, an application will often call C_GetMechanismList twice. However, this behavior is by no means required.
Return values: CKR_BUFFER_TOO_SMALL, CKR_CRYPTOKI_NOT_INITIALIZED, CKR_DEVICE_ERROR, CKR_DEVICE_MEMORY, CKR_DEVICE_REMOVED, CKR_FUNCTION_FAILED, CKR_GENERAL_ERROR, CKR_HOST_MEMORY, CKR_OK, CKR_SLOT_ID_INVALID, CKR_TOKEN_NOT_PRESENT, CKR_TOKEN_NOT_RECOGNIZED.
Example:
CK_SLOT_ID slotID;
CK_ULONG ulCount;
CK_MECHANISM_TYPE_PTR pMechanismList;
CK_RV rv;
.
.
.
rv = C_GetMechanismList(slotID, NULL_PTR, &ulCount);
if ((rv == CKR_OK) && (ulCount > 0)) {
pMechanismList =
(CK_MECHANISM_TYPE_PTR)
malloc(ulCount*sizeof(CK_MECHANISM_TYPE));
rv = C_GetMechanismList(slotID, pMechanismList, &ulCount);
if (rv == CKR_OK) {
.
.
.
}
free(pMechanismList);
}
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