/*
 * NT exception handling routines
 *
 * Copyright 1999 Turchanov Sergey
 * Copyright 1999 Alexandre Julliard
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include "config.h"
#include "wine/port.h"

#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdarg.h>

#include "ntstatus.h"
#define WIN32_NO_STATUS
#include "windef.h"
#include "winternl.h"
#include "wine/exception.h"
#include "wine/server.h"
#include "wine/list.h"
#include "wine/debug.h"
#include "excpt.h"
#include "ntdll_misc.h"

WINE_DEFAULT_DEBUG_CHANNEL(seh);

typedef struct
{
    struct list                 entry;
    PVECTORED_EXCEPTION_HANDLER func;
    ULONG                       count;
} VECTORED_HANDLER;

static struct list vectored_exception_handlers = LIST_INIT(vectored_exception_handlers);
static struct list vectored_continue_handlers  = LIST_INIT(vectored_continue_handlers);

static RTL_CRITICAL_SECTION vectored_handlers_section;
static RTL_CRITICAL_SECTION_DEBUG critsect_debug =
{
    0, 0, &vectored_handlers_section,
    { &critsect_debug.ProcessLocksList, &critsect_debug.ProcessLocksList },
      0, 0, { (DWORD_PTR)(__FILE__ ": vectored_handlers_section") }
};
static RTL_CRITICAL_SECTION vectored_handlers_section = { &critsect_debug, -1, 0, 0, 0, 0 };


static VECTORED_HANDLER *add_vectored_handler( struct list *handler_list, ULONG first,
                                               PVECTORED_EXCEPTION_HANDLER func )
{
    VECTORED_HANDLER *handler = RtlAllocateHeap( GetProcessHeap(), 0, sizeof(*handler) );
    if (handler)
    {
        handler->func = RtlEncodePointer( func );
        handler->count = 1;
        RtlEnterCriticalSection( &vectored_handlers_section );
        if (first) list_add_head( handler_list, &handler->entry );
        else list_add_tail( handler_list, &handler->entry );
        RtlLeaveCriticalSection( &vectored_handlers_section );
    }
    return handler;
}


static ULONG remove_vectored_handler( struct list *handler_list, VECTORED_HANDLER *handler )
{
    struct list *ptr;
    ULONG ret = FALSE;

    RtlEnterCriticalSection( &vectored_handlers_section );
    LIST_FOR_EACH( ptr, handler_list )
    {
        VECTORED_HANDLER *curr_handler = LIST_ENTRY( ptr, VECTORED_HANDLER, entry );
        if (curr_handler == handler)
        {
            if (!--curr_handler->count) list_remove( ptr );
            else handler = NULL;  /* don't free it yet */
            ret = TRUE;
            break;
        }
    }
    RtlLeaveCriticalSection( &vectored_handlers_section );
    if (ret) RtlFreeHeap( GetProcessHeap(), 0, handler );
    return ret;
}


/**********************************************************************
 *           wait_suspend
 *
 * Wait until the thread is no longer suspended.
 */
void wait_suspend( CONTEXT *context )
{
    LARGE_INTEGER timeout;
    int saved_errno = errno;
    context_t server_context;

    context_to_server( &server_context, context );

    /* store the context we got at suspend time */
    SERVER_START_REQ( set_suspend_context )
    {
        wine_server_add_data( req, &server_context, sizeof(server_context) );
        wine_server_call( req );
    }
    SERVER_END_REQ;

    /* wait with 0 timeout, will only return once the thread is no longer suspended */
    timeout.QuadPart = 0;
    server_select( NULL, 0, SELECT_INTERRUPTIBLE, &timeout );

    /* retrieve the new context */
    SERVER_START_REQ( get_suspend_context )
    {
        wine_server_set_reply( req, &server_context, sizeof(server_context) );
        wine_server_call( req );
    }
    SERVER_END_REQ;

    context_from_server( context, &server_context );
    errno = saved_errno;
}


/**********************************************************************
 *           send_debug_event
 *
 * Send an EXCEPTION_DEBUG_EVENT event to the debugger.
 */
NTSTATUS send_debug_event( EXCEPTION_RECORD *rec, int first_chance, CONTEXT *context )
{
    NTSTATUS ret;
    DWORD i;
    obj_handle_t handle = 0;
    client_ptr_t params[EXCEPTION_MAXIMUM_PARAMETERS];
    context_t server_context;
    select_op_t select_op;

    if (!NtCurrentTeb()->Peb->BeingDebugged) return 0;  /* no debugger present */

    for (i = 0; i < min( rec->NumberParameters, EXCEPTION_MAXIMUM_PARAMETERS ); i++)
        params[i] = rec->ExceptionInformation[i];

    context_to_server( &server_context, context );

    SERVER_START_REQ( queue_exception_event )
    {
        req->first   = first_chance;
        req->code    = rec->ExceptionCode;
        req->flags   = rec->ExceptionFlags;
        req->record  = wine_server_client_ptr( rec->ExceptionRecord );
        req->address = wine_server_client_ptr( rec->ExceptionAddress );
        req->len     = i * sizeof(params[0]);
        wine_server_add_data( req, params, req->len );
        wine_server_add_data( req, &server_context, sizeof(server_context) );
        if (!wine_server_call( req )) handle = reply->handle;
    }
    SERVER_END_REQ;
    if (!handle) return 0;

    select_op.wait.op = SELECT_WAIT;
    select_op.wait.handles[0] = handle;
    server_select( &select_op, offsetof( select_op_t, wait.handles[1] ), SELECT_INTERRUPTIBLE, NULL );

    SERVER_START_REQ( get_exception_status )
    {
        req->handle = handle;
        wine_server_set_reply( req, &server_context, sizeof(server_context) );
        ret = wine_server_call( req );
    }
    SERVER_END_REQ;
    if (ret >= 0) context_from_server( context, &server_context );
    return ret;
}


/**********************************************************************
 *           call_vectored_handlers
 *
 * Call the vectored handlers chain.
 */
LONG call_vectored_handlers( EXCEPTION_RECORD *rec, CONTEXT *context )
{
    struct list *ptr;
    LONG ret = EXCEPTION_CONTINUE_SEARCH;
    EXCEPTION_POINTERS except_ptrs;
    PVECTORED_EXCEPTION_HANDLER func;
    VECTORED_HANDLER *handler, *to_free = NULL;

    except_ptrs.ExceptionRecord = rec;
    except_ptrs.ContextRecord = context;

    RtlEnterCriticalSection( &vectored_handlers_section );
    ptr = list_head( &vectored_exception_handlers );
    while (ptr)
    {
        handler = LIST_ENTRY( ptr, VECTORED_HANDLER, entry );
        handler->count++;
        func = RtlDecodePointer( handler->func );
        RtlLeaveCriticalSection( &vectored_handlers_section );
        RtlFreeHeap( GetProcessHeap(), 0, to_free );
        to_free = NULL;

        TRACE( "calling handler at %p code=%x flags=%x\n",
               func, rec->ExceptionCode, rec->ExceptionFlags );
        ret = func( &except_ptrs );
        TRACE( "handler at %p returned %x\n", func, ret );

        RtlEnterCriticalSection( &vectored_handlers_section );
        ptr = list_next( &vectored_exception_handlers, ptr );
        if (!--handler->count)  /* removed during execution */
        {
            list_remove( &handler->entry );
            to_free = handler;
        }
        if (ret == EXCEPTION_CONTINUE_EXECUTION) break;
    }
    RtlLeaveCriticalSection( &vectored_handlers_section );
    RtlFreeHeap( GetProcessHeap(), 0, to_free );
    return ret;
}


/*******************************************************************
 *		raise_status
 *
 * Implementation of RtlRaiseStatus with a specific exception record.
 */
void raise_status( NTSTATUS status, EXCEPTION_RECORD *rec )
{
    EXCEPTION_RECORD ExceptionRec;

    ExceptionRec.ExceptionCode    = status;
    ExceptionRec.ExceptionFlags   = EH_NONCONTINUABLE;
    ExceptionRec.ExceptionRecord  = rec;
    ExceptionRec.NumberParameters = 0;
    for (;;) RtlRaiseException( &ExceptionRec );  /* never returns */
}


/***********************************************************************
 *            RtlRaiseStatus  (NTDLL.@)
 *
 * Raise an exception with ExceptionCode = status
 */
void WINAPI RtlRaiseStatus( NTSTATUS status )
{
    raise_status( status, NULL );
}


/*******************************************************************
 *         RtlAddVectoredContinueHandler   (NTDLL.@)
 */
PVOID WINAPI RtlAddVectoredContinueHandler( ULONG first, PVECTORED_EXCEPTION_HANDLER func )
{
    return add_vectored_handler( &vectored_continue_handlers, first, func );
}


/*******************************************************************
 *         RtlRemoveVectoredContinueHandler   (NTDLL.@)
 */
ULONG WINAPI RtlRemoveVectoredContinueHandler( PVOID handler )
{
    return remove_vectored_handler( &vectored_continue_handlers, handler );
}


/*******************************************************************
 *         RtlAddVectoredExceptionHandler   (NTDLL.@)
 */
PVOID WINAPI DECLSPEC_HOTPATCH RtlAddVectoredExceptionHandler( ULONG first, PVECTORED_EXCEPTION_HANDLER func )
{
    return add_vectored_handler( &vectored_exception_handlers, first, func );
}


/*******************************************************************
 *         RtlRemoveVectoredExceptionHandler   (NTDLL.@)
 */
ULONG WINAPI RtlRemoveVectoredExceptionHandler( PVOID handler )
{
    return remove_vectored_handler( &vectored_exception_handlers, handler );
}


/*************************************************************
 *            __wine_spec_unimplemented_stub
 *
 * ntdll-specific implementation to avoid depending on kernel functions.
 * Can be removed once ntdll.spec no longer contains stubs.
 */
void __wine_spec_unimplemented_stub( const char *module, const char *function )
{
    EXCEPTION_RECORD record;

    record.ExceptionCode    = EXCEPTION_WINE_STUB;
    record.ExceptionFlags   = EH_NONCONTINUABLE;
    record.ExceptionRecord  = NULL;
    record.ExceptionAddress = __wine_spec_unimplemented_stub;
    record.NumberParameters = 2;
    record.ExceptionInformation[0] = (ULONG_PTR)module;
    record.ExceptionInformation[1] = (ULONG_PTR)function;
    for (;;) RtlRaiseException( &record );
}