/* -*- Mode: rust; rust-indent-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#![allow(non_snake_case)]

extern crate byteorder;
extern crate pkcs11_bindings;
#[macro_use]
extern crate rsclientcerts;
extern crate sha2;

use pkcs11_bindings::*;
use rsclientcerts::manager::{Manager, SlotType};
use std::ffi::{c_void, CStr};
use std::sync::Mutex;

mod backend;

use backend::Backend;

type FindObjectsCallback = Option<
    unsafe extern "C" fn(
        typ: u8,
        data_len: usize,
        data: *const u8,
        extra_len: usize,
        extra: *const u8,
        slot_type: u32,
        ctx: *mut c_void,
    ),
>;

type FindObjectsFunction = extern "C" fn(callback: FindObjectsCallback, ctx: *mut c_void);

type SignCallback =
    Option<unsafe extern "C" fn(data_len: usize, data: *const u8, ctx: *mut c_void)>;

type SignFunction = extern "C" fn(
    cert_len: usize,
    cert: *const u8,
    data_len: usize,
    data: *const u8,
    params_len: usize,
    params: *const u8,
    callback: SignCallback,
    ctx: *mut c_void,
);

/// The singleton `Manager` that handles state with respect to PKCS #11. Only one thread
/// may use it at a time, but there is no restriction on which threads may use it.
static MANAGER: Mutex<Option<Manager<Backend>>> = Mutex::new(None);

// Obtaining a handle on the manager is a two-step process. First the mutex must be locked, which
// (if successful), results in a mutex guard object. We must then get a mutable refence to the
// underlying manager (if set - otherwise we return an error). This can't happen all in one macro
// without dropping a reference that needs to live long enough for this to be safe. In
// practice, this looks like:
//   let mut manager_guard = try_to_get_manager_guard!();
//   let manager = manager_guard_to_manager!(manager_guard);
macro_rules! try_to_get_manager_guard {
    () => {
        match MANAGER.lock() {
            Ok(maybe_manager) => maybe_manager,
            Err(_) => return CKR_DEVICE_ERROR,
        }
    };
}

macro_rules! manager_guard_to_manager {
    ($manager_guard:ident) => {
        match $manager_guard.as_mut() {
            Some(manager) => manager,
            None => return CKR_DEVICE_ERROR,
        }
    };
}

/// This gets called to initialize the module. For this implementation, this consists of
/// instantiating the `Manager`.
extern "C" fn C_Initialize(pInitArgs: CK_VOID_PTR) -> CK_RV {
    // pInitArgs.pReserved will be a c-string containing the base-16
    // stringification of the addresses of the functions to call to communicate
    // with the main process.
    if pInitArgs.is_null() {
        return CKR_DEVICE_ERROR;
    }
    let serialized_addresses_ptr = unsafe { (*(pInitArgs as CK_C_INITIALIZE_ARGS_PTR)).pReserved };
    if serialized_addresses_ptr.is_null() {
        return CKR_DEVICE_ERROR;
    }
    let serialized_addresses_cstr =
        unsafe { CStr::from_ptr(serialized_addresses_ptr as *mut std::os::raw::c_char) };
    let serialized_addresses = match serialized_addresses_cstr.to_str() {
        Ok(serialized_addresses) => serialized_addresses,
        Err(_) => return CKR_DEVICE_ERROR,
    };
    let function_addresses: Vec<usize> = serialized_addresses
        .split(',')
        .filter_map(|serialized_address| usize::from_str_radix(serialized_address, 16).ok())
        .collect();
    if function_addresses.len() != 2 {
        return CKR_DEVICE_ERROR;
    }
    let find_objects: FindObjectsFunction = unsafe { std::mem::transmute(function_addresses[0]) };
    let sign: SignFunction = unsafe { std::mem::transmute(function_addresses[1]) };
    let mut manager_guard = try_to_get_manager_guard!();
    let _unexpected_previous_manager =
        manager_guard.replace(Manager::new(Backend::new(find_objects, sign)));
    CKR_OK
}

extern "C" fn C_Finalize(_pReserved: CK_VOID_PTR) -> CK_RV {
    // Drop the manager. When C_Finalize is called, there should be only one
    // reference to this module (which is going away), so there shouldn't be
    // any concurrency issues.
    let mut manager_guard = try_to_get_manager_guard!();
    match manager_guard.take() {
        Some(_) => CKR_OK,
        None => CKR_CRYPTOKI_NOT_INITIALIZED,
    }
}

// The specification mandates that these strings be padded with spaces to the appropriate length.
// Since the length of fixed-size arrays in rust is part of the type, the compiler enforces that
// these byte strings are of the correct length.
const MANUFACTURER_ID_BYTES: &[u8; 32] = b"Mozilla Corporation             ";
const LIBRARY_DESCRIPTION_BYTES: &[u8; 32] = b"IPC Client Cert Module          ";

/// This gets called to gather some information about the module. In particular, this implementation
/// supports (portions of) cryptoki (PKCS #11) version 2.2.
extern "C" fn C_GetInfo(pInfo: CK_INFO_PTR) -> CK_RV {
    if pInfo.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    let mut info = CK_INFO::default();
    info.cryptokiVersion.major = 2;
    info.cryptokiVersion.minor = 2;
    info.manufacturerID = *MANUFACTURER_ID_BYTES;
    info.libraryDescription = *LIBRARY_DESCRIPTION_BYTES;
    unsafe {
        *pInfo = info;
    }
    CKR_OK
}

/// This module has two slots.
const SLOT_COUNT: CK_ULONG = 2;
/// The slot with ID 1 supports modern mechanisms like RSA-PSS.
const SLOT_ID_MODERN: CK_SLOT_ID = 1;
/// The slot with ID 2 only supports legacy mechanisms.
const SLOT_ID_LEGACY: CK_SLOT_ID = 2;

/// This gets called twice: once with a null `pSlotList` to get the number of slots (returned via
/// `pulCount`) and a second time to get the ID for each slot.
extern "C" fn C_GetSlotList(
    _tokenPresent: CK_BBOOL,
    pSlotList: CK_SLOT_ID_PTR,
    pulCount: CK_ULONG_PTR,
) -> CK_RV {
    if pulCount.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    if !pSlotList.is_null() {
        if unsafe { *pulCount } < SLOT_COUNT {
            return CKR_BUFFER_TOO_SMALL;
        }
        unsafe {
            *pSlotList = SLOT_ID_MODERN;
            *pSlotList.offset(1) = SLOT_ID_LEGACY;
        }
    };
    unsafe {
        *pulCount = SLOT_COUNT;
    }
    CKR_OK
}

const SLOT_DESCRIPTION_MODERN_BYTES: &[u8; 64] =
    b"IPC Client Cert Slot (Modern)                                   ";
const SLOT_DESCRIPTION_LEGACY_BYTES: &[u8; 64] =
    b"IPC Client Cert Slot (Legacy)                                   ";

/// This gets called to obtain information about slots. In this implementation, the tokens are
/// always present in the slots.
extern "C" fn C_GetSlotInfo(slotID: CK_SLOT_ID, pInfo: CK_SLOT_INFO_PTR) -> CK_RV {
    if (slotID != SLOT_ID_MODERN && slotID != SLOT_ID_LEGACY) || pInfo.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    let description = if slotID == SLOT_ID_MODERN {
        SLOT_DESCRIPTION_MODERN_BYTES
    } else {
        SLOT_DESCRIPTION_LEGACY_BYTES
    };
    let slot_info = CK_SLOT_INFO {
        slotDescription: *description,
        manufacturerID: *MANUFACTURER_ID_BYTES,
        flags: CKF_TOKEN_PRESENT,
        hardwareVersion: CK_VERSION::default(),
        firmwareVersion: CK_VERSION::default(),
    };
    unsafe {
        *pInfo = slot_info;
    }
    CKR_OK
}

const TOKEN_LABEL_MODERN_BYTES: &[u8; 32] = b"IPC Client Cert Token (Modern)  ";
const TOKEN_LABEL_LEGACY_BYTES: &[u8; 32] = b"IPC Client Cert Token (Legacy)  ";
const TOKEN_MODEL_BYTES: &[u8; 16] = b"ipcclientcerts  ";
const TOKEN_SERIAL_NUMBER_BYTES: &[u8; 16] = b"0000000000000000";

/// This gets called to obtain some information about tokens. This implementation has two slots,
/// so it has two tokens. This information is primarily for display purposes.
extern "C" fn C_GetTokenInfo(slotID: CK_SLOT_ID, pInfo: CK_TOKEN_INFO_PTR) -> CK_RV {
    if (slotID != SLOT_ID_MODERN && slotID != SLOT_ID_LEGACY) || pInfo.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    let mut token_info = CK_TOKEN_INFO::default();
    let label = if slotID == SLOT_ID_MODERN {
        TOKEN_LABEL_MODERN_BYTES
    } else {
        TOKEN_LABEL_LEGACY_BYTES
    };
    token_info.label = *label;
    token_info.manufacturerID = *MANUFACTURER_ID_BYTES;
    token_info.model = *TOKEN_MODEL_BYTES;
    token_info.serialNumber = *TOKEN_SERIAL_NUMBER_BYTES;
    unsafe {
        *pInfo = token_info;
    }
    CKR_OK
}

/// This gets called to determine what mechanisms a slot supports. The modern slot supports ECDSA,
/// RSA PKCS, and RSA PSS. The legacy slot only supports RSA PKCS.
extern "C" fn C_GetMechanismList(
    slotID: CK_SLOT_ID,
    pMechanismList: CK_MECHANISM_TYPE_PTR,
    pulCount: CK_ULONG_PTR,
) -> CK_RV {
    if (slotID != SLOT_ID_MODERN && slotID != SLOT_ID_LEGACY) || pulCount.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    let mechanisms = if slotID == SLOT_ID_MODERN {
        vec![CKM_ECDSA, CKM_RSA_PKCS, CKM_RSA_PKCS_PSS]
    } else {
        vec![CKM_RSA_PKCS]
    };
    if !pMechanismList.is_null() {
        if unsafe { *pulCount as usize } < mechanisms.len() {
            return CKR_ARGUMENTS_BAD;
        }
        for i in 0..mechanisms.len() {
            unsafe {
                *pMechanismList.offset(i as isize) = mechanisms[i];
            }
        }
    }
    unsafe {
        *pulCount = mechanisms.len() as CK_ULONG;
    }
    CKR_OK
}

extern "C" fn C_GetMechanismInfo(
    _slotID: CK_SLOT_ID,
    _type: CK_MECHANISM_TYPE,
    _pInfo: CK_MECHANISM_INFO_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_InitToken(
    _slotID: CK_SLOT_ID,
    _pPin: CK_UTF8CHAR_PTR,
    _ulPinLen: CK_ULONG,
    _pLabel: CK_UTF8CHAR_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_InitPIN(
    _hSession: CK_SESSION_HANDLE,
    _pPin: CK_UTF8CHAR_PTR,
    _ulPinLen: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_SetPIN(
    _hSession: CK_SESSION_HANDLE,
    _pOldPin: CK_UTF8CHAR_PTR,
    _ulOldLen: CK_ULONG,
    _pNewPin: CK_UTF8CHAR_PTR,
    _ulNewLen: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

/// This gets called to create a new session. This module defers to the `ManagerProxy` to implement
/// this.
extern "C" fn C_OpenSession(
    slotID: CK_SLOT_ID,
    _flags: CK_FLAGS,
    _pApplication: CK_VOID_PTR,
    _Notify: CK_NOTIFY,
    phSession: CK_SESSION_HANDLE_PTR,
) -> CK_RV {
    if (slotID != SLOT_ID_MODERN && slotID != SLOT_ID_LEGACY) || phSession.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    let mut manager_guard = try_to_get_manager_guard!();
    let manager = manager_guard_to_manager!(manager_guard);
    let slot_type = if slotID == SLOT_ID_MODERN {
        SlotType::Modern
    } else {
        SlotType::Legacy
    };
    let session_handle = match manager.open_session(slot_type) {
        Ok(session_handle) => session_handle,
        Err(_) => return CKR_DEVICE_ERROR,
    };
    unsafe {
        *phSession = session_handle;
    }
    CKR_OK
}

/// This gets called to close a session. This is handled by the `ManagerProxy`.
extern "C" fn C_CloseSession(hSession: CK_SESSION_HANDLE) -> CK_RV {
    let mut manager_guard = try_to_get_manager_guard!();
    let manager = manager_guard_to_manager!(manager_guard);
    if manager.close_session(hSession).is_err() {
        return CKR_SESSION_HANDLE_INVALID;
    }
    CKR_OK
}

/// This gets called to close all open sessions at once. This is handled by the `ManagerProxy`.
extern "C" fn C_CloseAllSessions(slotID: CK_SLOT_ID) -> CK_RV {
    if slotID != SLOT_ID_MODERN && slotID != SLOT_ID_LEGACY {
        return CKR_ARGUMENTS_BAD;
    }
    let mut manager_guard = try_to_get_manager_guard!();
    let manager = manager_guard_to_manager!(manager_guard);
    let slot_type = if slotID == SLOT_ID_MODERN {
        SlotType::Modern
    } else {
        SlotType::Legacy
    };
    match manager.close_all_sessions(slot_type) {
        Ok(()) => CKR_OK,
        Err(_) => CKR_DEVICE_ERROR,
    }
}

extern "C" fn C_GetSessionInfo(_hSession: CK_SESSION_HANDLE, _pInfo: CK_SESSION_INFO_PTR) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_GetOperationState(
    _hSession: CK_SESSION_HANDLE,
    _pOperationState: CK_BYTE_PTR,
    _pulOperationStateLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_SetOperationState(
    _hSession: CK_SESSION_HANDLE,
    _pOperationState: CK_BYTE_PTR,
    _ulOperationStateLen: CK_ULONG,
    _hEncryptionKey: CK_OBJECT_HANDLE,
    _hAuthenticationKey: CK_OBJECT_HANDLE,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_Login(
    _hSession: CK_SESSION_HANDLE,
    _userType: CK_USER_TYPE,
    _pPin: CK_UTF8CHAR_PTR,
    _ulPinLen: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

/// This gets called to log out and drop any authenticated resources. Because this module does not
/// hold on to authenticated resources, this module "implements" this by doing nothing and
/// returning a success result.
extern "C" fn C_Logout(_hSession: CK_SESSION_HANDLE) -> CK_RV {
    CKR_OK
}

extern "C" fn C_CreateObject(
    _hSession: CK_SESSION_HANDLE,
    _pTemplate: CK_ATTRIBUTE_PTR,
    _ulCount: CK_ULONG,
    _phObject: CK_OBJECT_HANDLE_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_CopyObject(
    _hSession: CK_SESSION_HANDLE,
    _hObject: CK_OBJECT_HANDLE,
    _pTemplate: CK_ATTRIBUTE_PTR,
    _ulCount: CK_ULONG,
    _phNewObject: CK_OBJECT_HANDLE_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DestroyObject(_hSession: CK_SESSION_HANDLE, _hObject: CK_OBJECT_HANDLE) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_GetObjectSize(
    _hSession: CK_SESSION_HANDLE,
    _hObject: CK_OBJECT_HANDLE,
    _pulSize: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

/// This gets called to obtain the values of a number of attributes of an object identified by the
/// given handle. This module implements this by requesting that the `ManagerProxy` find the object
/// and attempt to get the value of each attribute. If a specified attribute is not defined on the
/// object, the length of that attribute is set to -1 to indicate that it is not available.
/// This gets called twice: once to obtain the lengths of the attributes and again to get the
/// values.
extern "C" fn C_GetAttributeValue(
    _hSession: CK_SESSION_HANDLE,
    hObject: CK_OBJECT_HANDLE,
    pTemplate: CK_ATTRIBUTE_PTR,
    ulCount: CK_ULONG,
) -> CK_RV {
    if pTemplate.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    let mut attr_types = Vec::with_capacity(ulCount as usize);
    for i in 0..ulCount {
        let attr = unsafe { &*pTemplate.offset(i as isize) };
        attr_types.push(attr.type_);
    }
    let mut manager_guard = try_to_get_manager_guard!();
    let manager = manager_guard_to_manager!(manager_guard);
    let values = match manager.get_attributes(hObject, attr_types) {
        Ok(values) => values,
        Err(_) => return CKR_ARGUMENTS_BAD,
    };
    if values.len() != ulCount as usize {
        return CKR_DEVICE_ERROR;
    }
    for i in 0..ulCount as usize {
        let mut attr = unsafe { &mut *pTemplate.offset(i as isize) };
        // NB: the safety of this array access depends on the length check above
        if let Some(attr_value) = &values[i] {
            if attr.pValue.is_null() {
                attr.ulValueLen = attr_value.len() as CK_ULONG;
            } else {
                let ptr: *mut u8 = attr.pValue as *mut u8;
                if attr_value.len() != attr.ulValueLen as usize {
                    return CKR_ARGUMENTS_BAD;
                }
                unsafe {
                    std::ptr::copy_nonoverlapping(attr_value.as_ptr(), ptr, attr_value.len());
                }
            }
        } else {
            attr.ulValueLen = (0 - 1) as CK_ULONG;
        }
    }
    CKR_OK
}

extern "C" fn C_SetAttributeValue(
    _hSession: CK_SESSION_HANDLE,
    _hObject: CK_OBJECT_HANDLE,
    _pTemplate: CK_ATTRIBUTE_PTR,
    _ulCount: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

/// This gets called to initialize a search for objects matching a given list of attributes. This
/// module implements this by gathering the attributes and passing them to the `ManagerProxy` to
/// start the search.
extern "C" fn C_FindObjectsInit(
    hSession: CK_SESSION_HANDLE,
    pTemplate: CK_ATTRIBUTE_PTR,
    ulCount: CK_ULONG,
) -> CK_RV {
    if pTemplate.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    let mut attrs = Vec::new();
    for i in 0..ulCount {
        let attr = unsafe { &*pTemplate.offset(i as isize) };
        let slice = unsafe {
            std::slice::from_raw_parts(attr.pValue as *const u8, attr.ulValueLen as usize)
        };
        attrs.push((attr.type_, slice.to_owned()));
    }
    let mut manager_guard = try_to_get_manager_guard!();
    let manager = manager_guard_to_manager!(manager_guard);
    match manager.start_search(hSession, attrs) {
        Ok(()) => {}
        Err(_) => return CKR_ARGUMENTS_BAD,
    }
    CKR_OK
}

/// This gets called after `C_FindObjectsInit` to get the results of a search. This module
/// implements this by looking up the search in the `ManagerProxy` and copying out the matching
/// object handles.
extern "C" fn C_FindObjects(
    hSession: CK_SESSION_HANDLE,
    phObject: CK_OBJECT_HANDLE_PTR,
    ulMaxObjectCount: CK_ULONG,
    pulObjectCount: CK_ULONG_PTR,
) -> CK_RV {
    if phObject.is_null() || pulObjectCount.is_null() || ulMaxObjectCount == 0 {
        return CKR_ARGUMENTS_BAD;
    }
    let mut manager_guard = try_to_get_manager_guard!();
    let manager = manager_guard_to_manager!(manager_guard);
    let handles = match manager.search(hSession, ulMaxObjectCount as usize) {
        Ok(handles) => handles,
        Err(_) => return CKR_ARGUMENTS_BAD,
    };
    if handles.len() > ulMaxObjectCount as usize {
        return CKR_DEVICE_ERROR;
    }
    unsafe {
        *pulObjectCount = handles.len() as CK_ULONG;
    }
    for (index, handle) in handles.iter().enumerate() {
        if index < ulMaxObjectCount as usize {
            unsafe {
                *(phObject.add(index)) = *handle;
            }
        }
    }
    CKR_OK
}

/// This gets called after `C_FindObjectsInit` and `C_FindObjects` to finish a search. The module
/// tells the `ManagerProxy` to clear the search.
extern "C" fn C_FindObjectsFinal(hSession: CK_SESSION_HANDLE) -> CK_RV {
    let mut manager_guard = try_to_get_manager_guard!();
    let manager = manager_guard_to_manager!(manager_guard);
    // It would be an error if there were no search for this session, but we can be permissive here.
    match manager.clear_search(hSession) {
        Ok(()) => CKR_OK,
        Err(_) => CKR_DEVICE_ERROR,
    }
}

extern "C" fn C_EncryptInit(
    _hSession: CK_SESSION_HANDLE,
    _pMechanism: CK_MECHANISM_PTR,
    _hKey: CK_OBJECT_HANDLE,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_Encrypt(
    _hSession: CK_SESSION_HANDLE,
    _pData: CK_BYTE_PTR,
    _ulDataLen: CK_ULONG,
    _pEncryptedData: CK_BYTE_PTR,
    _pulEncryptedDataLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_EncryptUpdate(
    _hSession: CK_SESSION_HANDLE,
    _pPart: CK_BYTE_PTR,
    _ulPartLen: CK_ULONG,
    _pEncryptedPart: CK_BYTE_PTR,
    _pulEncryptedPartLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_EncryptFinal(
    _hSession: CK_SESSION_HANDLE,
    _pLastEncryptedPart: CK_BYTE_PTR,
    _pulLastEncryptedPartLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DecryptInit(
    _hSession: CK_SESSION_HANDLE,
    _pMechanism: CK_MECHANISM_PTR,
    _hKey: CK_OBJECT_HANDLE,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_Decrypt(
    _hSession: CK_SESSION_HANDLE,
    _pEncryptedData: CK_BYTE_PTR,
    _ulEncryptedDataLen: CK_ULONG,
    _pData: CK_BYTE_PTR,
    _pulDataLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DecryptUpdate(
    _hSession: CK_SESSION_HANDLE,
    _pEncryptedPart: CK_BYTE_PTR,
    _ulEncryptedPartLen: CK_ULONG,
    _pPart: CK_BYTE_PTR,
    _pulPartLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DecryptFinal(
    _hSession: CK_SESSION_HANDLE,
    _pLastPart: CK_BYTE_PTR,
    _pulLastPartLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DigestInit(_hSession: CK_SESSION_HANDLE, _pMechanism: CK_MECHANISM_PTR) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_Digest(
    _hSession: CK_SESSION_HANDLE,
    _pData: CK_BYTE_PTR,
    _ulDataLen: CK_ULONG,
    _pDigest: CK_BYTE_PTR,
    _pulDigestLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DigestUpdate(
    _hSession: CK_SESSION_HANDLE,
    _pPart: CK_BYTE_PTR,
    _ulPartLen: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DigestKey(_hSession: CK_SESSION_HANDLE, _hKey: CK_OBJECT_HANDLE) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DigestFinal(
    _hSession: CK_SESSION_HANDLE,
    _pDigest: CK_BYTE_PTR,
    _pulDigestLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

/// This gets called to set up a sign operation. The module essentially defers to the
/// `ManagerProxy`.
extern "C" fn C_SignInit(
    hSession: CK_SESSION_HANDLE,
    pMechanism: CK_MECHANISM_PTR,
    hKey: CK_OBJECT_HANDLE,
) -> CK_RV {
    if pMechanism.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    // Presumably we should validate the mechanism against hKey, but the specification doesn't
    // actually seem to require this.
    let mechanism = unsafe { *pMechanism };
    let mechanism_params = if mechanism.mechanism == CKM_RSA_PKCS_PSS {
        if mechanism.ulParameterLen as usize != std::mem::size_of::<CK_RSA_PKCS_PSS_PARAMS>() {
            return CKR_ARGUMENTS_BAD;
        }
        Some(unsafe { *(mechanism.pParameter as *const CK_RSA_PKCS_PSS_PARAMS) })
    } else {
        None
    };
    let mut manager_guard = try_to_get_manager_guard!();
    let manager = manager_guard_to_manager!(manager_guard);
    match manager.start_sign(hSession, hKey, mechanism_params) {
        Ok(()) => {}
        Err(_) => return CKR_GENERAL_ERROR,
    };
    CKR_OK
}

/// NSS calls this after `C_SignInit` (there are more ways in the PKCS #11 specification to sign
/// data, but this is the only way supported by this module). The module essentially defers to the
/// `ManagerProxy` and copies out the resulting signature.
extern "C" fn C_Sign(
    hSession: CK_SESSION_HANDLE,
    pData: CK_BYTE_PTR,
    ulDataLen: CK_ULONG,
    pSignature: CK_BYTE_PTR,
    pulSignatureLen: CK_ULONG_PTR,
) -> CK_RV {
    if pData.is_null() || pulSignatureLen.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    let data = unsafe { std::slice::from_raw_parts(pData, ulDataLen as usize) };
    if pSignature.is_null() {
        let mut manager_guard = try_to_get_manager_guard!();
        let manager = manager_guard_to_manager!(manager_guard);
        match manager.get_signature_length(hSession, data.to_vec()) {
            Ok(signature_length) => unsafe {
                *pulSignatureLen = signature_length as CK_ULONG;
            },
            Err(_) => return CKR_GENERAL_ERROR,
        }
    } else {
        let mut manager_guard = try_to_get_manager_guard!();
        let manager = manager_guard_to_manager!(manager_guard);
        match manager.sign(hSession, data.to_vec()) {
            Ok(signature) => {
                let signature_capacity = unsafe { *pulSignatureLen } as usize;
                if signature_capacity < signature.len() {
                    return CKR_ARGUMENTS_BAD;
                }
                let ptr: *mut u8 = pSignature as *mut u8;
                unsafe {
                    std::ptr::copy_nonoverlapping(signature.as_ptr(), ptr, signature.len());
                    *pulSignatureLen = signature.len() as CK_ULONG;
                }
            }
            Err(_) => return CKR_GENERAL_ERROR,
        }
    }
    CKR_OK
}

extern "C" fn C_SignUpdate(
    _hSession: CK_SESSION_HANDLE,
    _pPart: CK_BYTE_PTR,
    _ulPartLen: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_SignFinal(
    _hSession: CK_SESSION_HANDLE,
    _pSignature: CK_BYTE_PTR,
    _pulSignatureLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_SignRecoverInit(
    _hSession: CK_SESSION_HANDLE,
    _pMechanism: CK_MECHANISM_PTR,
    _hKey: CK_OBJECT_HANDLE,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_SignRecover(
    _hSession: CK_SESSION_HANDLE,
    _pData: CK_BYTE_PTR,
    _ulDataLen: CK_ULONG,
    _pSignature: CK_BYTE_PTR,
    _pulSignatureLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_VerifyInit(
    _hSession: CK_SESSION_HANDLE,
    _pMechanism: CK_MECHANISM_PTR,
    _hKey: CK_OBJECT_HANDLE,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_Verify(
    _hSession: CK_SESSION_HANDLE,
    _pData: CK_BYTE_PTR,
    _ulDataLen: CK_ULONG,
    _pSignature: CK_BYTE_PTR,
    _ulSignatureLen: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_VerifyUpdate(
    _hSession: CK_SESSION_HANDLE,
    _pPart: CK_BYTE_PTR,
    _ulPartLen: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_VerifyFinal(
    _hSession: CK_SESSION_HANDLE,
    _pSignature: CK_BYTE_PTR,
    _ulSignatureLen: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_VerifyRecoverInit(
    _hSession: CK_SESSION_HANDLE,
    _pMechanism: CK_MECHANISM_PTR,
    _hKey: CK_OBJECT_HANDLE,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_VerifyRecover(
    _hSession: CK_SESSION_HANDLE,
    _pSignature: CK_BYTE_PTR,
    _ulSignatureLen: CK_ULONG,
    _pData: CK_BYTE_PTR,
    _pulDataLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DigestEncryptUpdate(
    _hSession: CK_SESSION_HANDLE,
    _pPart: CK_BYTE_PTR,
    _ulPartLen: CK_ULONG,
    _pEncryptedPart: CK_BYTE_PTR,
    _pulEncryptedPartLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DecryptDigestUpdate(
    _hSession: CK_SESSION_HANDLE,
    _pEncryptedPart: CK_BYTE_PTR,
    _ulEncryptedPartLen: CK_ULONG,
    _pPart: CK_BYTE_PTR,
    _pulPartLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_SignEncryptUpdate(
    _hSession: CK_SESSION_HANDLE,
    _pPart: CK_BYTE_PTR,
    _ulPartLen: CK_ULONG,
    _pEncryptedPart: CK_BYTE_PTR,
    _pulEncryptedPartLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DecryptVerifyUpdate(
    _hSession: CK_SESSION_HANDLE,
    _pEncryptedPart: CK_BYTE_PTR,
    _ulEncryptedPartLen: CK_ULONG,
    _pPart: CK_BYTE_PTR,
    _pulPartLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_GenerateKey(
    _hSession: CK_SESSION_HANDLE,
    _pMechanism: CK_MECHANISM_PTR,
    _pTemplate: CK_ATTRIBUTE_PTR,
    _ulCount: CK_ULONG,
    _phKey: CK_OBJECT_HANDLE_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_GenerateKeyPair(
    _hSession: CK_SESSION_HANDLE,
    _pMechanism: CK_MECHANISM_PTR,
    _pPublicKeyTemplate: CK_ATTRIBUTE_PTR,
    _ulPublicKeyAttributeCount: CK_ULONG,
    _pPrivateKeyTemplate: CK_ATTRIBUTE_PTR,
    _ulPrivateKeyAttributeCount: CK_ULONG,
    _phPublicKey: CK_OBJECT_HANDLE_PTR,
    _phPrivateKey: CK_OBJECT_HANDLE_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_WrapKey(
    _hSession: CK_SESSION_HANDLE,
    _pMechanism: CK_MECHANISM_PTR,
    _hWrappingKey: CK_OBJECT_HANDLE,
    _hKey: CK_OBJECT_HANDLE,
    _pWrappedKey: CK_BYTE_PTR,
    _pulWrappedKeyLen: CK_ULONG_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_UnwrapKey(
    _hSession: CK_SESSION_HANDLE,
    _pMechanism: CK_MECHANISM_PTR,
    _hUnwrappingKey: CK_OBJECT_HANDLE,
    _pWrappedKey: CK_BYTE_PTR,
    _ulWrappedKeyLen: CK_ULONG,
    _pTemplate: CK_ATTRIBUTE_PTR,
    _ulAttributeCount: CK_ULONG,
    _phKey: CK_OBJECT_HANDLE_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_DeriveKey(
    _hSession: CK_SESSION_HANDLE,
    _pMechanism: CK_MECHANISM_PTR,
    _hBaseKey: CK_OBJECT_HANDLE,
    _pTemplate: CK_ATTRIBUTE_PTR,
    _ulAttributeCount: CK_ULONG,
    _phKey: CK_OBJECT_HANDLE_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_SeedRandom(
    _hSession: CK_SESSION_HANDLE,
    _pSeed: CK_BYTE_PTR,
    _ulSeedLen: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_GenerateRandom(
    _hSession: CK_SESSION_HANDLE,
    _RandomData: CK_BYTE_PTR,
    _ulRandomLen: CK_ULONG,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_GetFunctionStatus(_hSession: CK_SESSION_HANDLE) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_CancelFunction(_hSession: CK_SESSION_HANDLE) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

extern "C" fn C_WaitForSlotEvent(
    _flags: CK_FLAGS,
    _pSlot: CK_SLOT_ID_PTR,
    _pRserved: CK_VOID_PTR,
) -> CK_RV {
    CKR_FUNCTION_NOT_SUPPORTED
}

/// To be a valid PKCS #11 module, this list of functions must be supported. At least cryptoki 2.2
/// must be supported for this module to work in NSS.
static mut FUNCTION_LIST: CK_FUNCTION_LIST = CK_FUNCTION_LIST {
    version: CK_VERSION { major: 2, minor: 2 },
    C_Initialize: Some(C_Initialize),
    C_Finalize: Some(C_Finalize),
    C_GetInfo: Some(C_GetInfo),
    C_GetFunctionList: None,
    C_GetSlotList: Some(C_GetSlotList),
    C_GetSlotInfo: Some(C_GetSlotInfo),
    C_GetTokenInfo: Some(C_GetTokenInfo),
    C_GetMechanismList: Some(C_GetMechanismList),
    C_GetMechanismInfo: Some(C_GetMechanismInfo),
    C_InitToken: Some(C_InitToken),
    C_InitPIN: Some(C_InitPIN),
    C_SetPIN: Some(C_SetPIN),
    C_OpenSession: Some(C_OpenSession),
    C_CloseSession: Some(C_CloseSession),
    C_CloseAllSessions: Some(C_CloseAllSessions),
    C_GetSessionInfo: Some(C_GetSessionInfo),
    C_GetOperationState: Some(C_GetOperationState),
    C_SetOperationState: Some(C_SetOperationState),
    C_Login: Some(C_Login),
    C_Logout: Some(C_Logout),
    C_CreateObject: Some(C_CreateObject),
    C_CopyObject: Some(C_CopyObject),
    C_DestroyObject: Some(C_DestroyObject),
    C_GetObjectSize: Some(C_GetObjectSize),
    C_GetAttributeValue: Some(C_GetAttributeValue),
    C_SetAttributeValue: Some(C_SetAttributeValue),
    C_FindObjectsInit: Some(C_FindObjectsInit),
    C_FindObjects: Some(C_FindObjects),
    C_FindObjectsFinal: Some(C_FindObjectsFinal),
    C_EncryptInit: Some(C_EncryptInit),
    C_Encrypt: Some(C_Encrypt),
    C_EncryptUpdate: Some(C_EncryptUpdate),
    C_EncryptFinal: Some(C_EncryptFinal),
    C_DecryptInit: Some(C_DecryptInit),
    C_Decrypt: Some(C_Decrypt),
    C_DecryptUpdate: Some(C_DecryptUpdate),
    C_DecryptFinal: Some(C_DecryptFinal),
    C_DigestInit: Some(C_DigestInit),
    C_Digest: Some(C_Digest),
    C_DigestUpdate: Some(C_DigestUpdate),
    C_DigestKey: Some(C_DigestKey),
    C_DigestFinal: Some(C_DigestFinal),
    C_SignInit: Some(C_SignInit),
    C_Sign: Some(C_Sign),
    C_SignUpdate: Some(C_SignUpdate),
    C_SignFinal: Some(C_SignFinal),
    C_SignRecoverInit: Some(C_SignRecoverInit),
    C_SignRecover: Some(C_SignRecover),
    C_VerifyInit: Some(C_VerifyInit),
    C_Verify: Some(C_Verify),
    C_VerifyUpdate: Some(C_VerifyUpdate),
    C_VerifyFinal: Some(C_VerifyFinal),
    C_VerifyRecoverInit: Some(C_VerifyRecoverInit),
    C_VerifyRecover: Some(C_VerifyRecover),
    C_DigestEncryptUpdate: Some(C_DigestEncryptUpdate),
    C_DecryptDigestUpdate: Some(C_DecryptDigestUpdate),
    C_SignEncryptUpdate: Some(C_SignEncryptUpdate),
    C_DecryptVerifyUpdate: Some(C_DecryptVerifyUpdate),
    C_GenerateKey: Some(C_GenerateKey),
    C_GenerateKeyPair: Some(C_GenerateKeyPair),
    C_WrapKey: Some(C_WrapKey),
    C_UnwrapKey: Some(C_UnwrapKey),
    C_DeriveKey: Some(C_DeriveKey),
    C_SeedRandom: Some(C_SeedRandom),
    C_GenerateRandom: Some(C_GenerateRandom),
    C_GetFunctionStatus: Some(C_GetFunctionStatus),
    C_CancelFunction: Some(C_CancelFunction),
    C_WaitForSlotEvent: Some(C_WaitForSlotEvent),
};

/// This is the only function this module exposes. The C stub calls it when NSS
/// calls its exposed C_GetFunctionList function to obtain the list of functions
/// comprising this module.
#[no_mangle]
pub extern "C" fn IPCCC_GetFunctionList(ppFunctionList: CK_FUNCTION_LIST_PTR_PTR) -> CK_RV {
    if ppFunctionList.is_null() {
        return CKR_ARGUMENTS_BAD;
    }
    unsafe {
        *ppFunctionList = &mut FUNCTION_LIST;
    }
    CKR_OK
}

#[cfg_attr(target_os = "macos", link(name = "Security", kind = "framework"))]
extern "C" {}