/*
 * Win32 virtual memory functions
 *
 * Copyright 1997 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 <fcntl.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif

#define WINE_NO_INLINE_STRING
#include "ntstatus.h"
#define WIN32_NO_STATUS
#define NONAMELESSUNION
#include "windef.h"
#include "winbase.h"
#include "winnls.h"
#include "winternl.h"
#include "winerror.h"
#include "psapi.h"
#include "wine/exception.h"
#include "wine/unicode.h"
#include "wine/debug.h"

#include "kernel_private.h"

WINE_DEFAULT_DEBUG_CHANNEL(seh);


static LONG WINAPI badptr_handler( EXCEPTION_POINTERS *eptr )
{
    EXCEPTION_RECORD *rec = eptr->ExceptionRecord;

    if (rec->ExceptionCode == STATUS_ACCESS_VIOLATION) return EXCEPTION_EXECUTE_HANDLER;
    if (rec->ExceptionCode == STATUS_STACK_OVERFLOW)
    {
        /* restore stack guard page */
        void *addr = (char *)NtCurrentTeb()->DeallocationStack + system_info.PageSize;
        SIZE_T size = (char *)rec - (char *)addr;
        ULONG old_prot;
        NtProtectVirtualMemory( GetCurrentProcess(), &addr, &size, PAGE_GUARD|PAGE_READWRITE, &old_prot );
        return EXCEPTION_EXECUTE_HANDLER;
    }
    return EXCEPTION_CONTINUE_SEARCH;
}

/***********************************************************************
 *             IsBadReadPtr   (KERNEL32.@)
 *
 * Check for read access on a memory block.
 *
 * ptr  [I] Address of memory block.
 * size [I] Size of block.
 *
 * RETURNS
 *  Success: TRUE.
 *	Failure: FALSE. Process has read access to entire block.
 */
BOOL WINAPI IsBadReadPtr( LPCVOID ptr, UINT_PTR size )
{
    if (!size) return FALSE;  /* handle 0 size case w/o reference */
    if (!ptr) return TRUE;
    __TRY
    {
        volatile const char *p = ptr;
        char dummy __attribute__((unused));
        UINT_PTR count = size;

        while (count > system_info.PageSize)
        {
            dummy = *p;
            p += system_info.PageSize;
            count -= system_info.PageSize;
        }
        dummy = p[0];
        dummy = p[count - 1];
    }
    __EXCEPT( badptr_handler )
    {
        TRACE("%p caused page fault during read\n", ptr);
        return TRUE;
    }
    __ENDTRY
    return FALSE;
}


/***********************************************************************
 *             IsBadWritePtr   (KERNEL32.@)
 *
 * Check for write access on a memory block.
 *
 * PARAMS
 *  ptr  [I] Address of memory block.
 *  size [I] Size of block in bytes.
 *
 * RETURNS
 *  Success: TRUE.
 *	Failure: FALSE. Process has write access to entire block.
 */
BOOL WINAPI IsBadWritePtr( LPVOID ptr, UINT_PTR size )
{
    if (!size) return FALSE;  /* handle 0 size case w/o reference */
    if (!ptr) return TRUE;
    __TRY
    {
        volatile char *p = ptr;
        UINT_PTR count = size;

        while (count > system_info.PageSize)
        {
            *p |= 0;
            p += system_info.PageSize;
            count -= system_info.PageSize;
        }
        p[0] |= 0;
        p[count - 1] |= 0;
    }
    __EXCEPT( badptr_handler )
    {
        TRACE("%p caused page fault during write\n", ptr);
        return TRUE;
    }
    __ENDTRY
    return FALSE;
}


/***********************************************************************
 *             IsBadHugeReadPtr   (KERNEL32.@)
 *
 * Check for read access on a memory block.
 *
 * PARAMS
 *  ptr  [I] Address of memory block.
 *  size [I] Size of block.
 *
 * RETURNS
 *  Success: TRUE.
 *	Failure: FALSE. Process has read access to entire block.
 */
BOOL WINAPI IsBadHugeReadPtr( LPCVOID ptr, UINT_PTR size )
{
    return IsBadReadPtr( ptr, size );
}


/***********************************************************************
 *             IsBadHugeWritePtr   (KERNEL32.@)
 *
 * Check for write access on a memory block.
 *
 * PARAMS
 *  ptr  [I] Address of memory block.
 *  size [I] Size of block.
 *
 * RETURNS
 *  Success: TRUE.
 *	Failure: FALSE. Process has write access to entire block.
 */
BOOL WINAPI IsBadHugeWritePtr( LPVOID ptr, UINT_PTR size )
{
    return IsBadWritePtr( ptr, size );
}


/***********************************************************************
 *             IsBadCodePtr   (KERNEL32.@)
 *
 * Check for read access on a memory address.
 *
 * PARAMS
 *  ptr [I] Address of function.
 *
 * RETURNS
 *	Success: TRUE.
 *	Failure: FALSE. Process has read access to specified memory.
 */
BOOL WINAPI IsBadCodePtr( FARPROC ptr )
{
    return IsBadReadPtr( ptr, 1 );
}


/***********************************************************************
 *             IsBadStringPtrA   (KERNEL32.@)
 *
 * Check for read access on a range of memory pointed to by a string pointer.
 *
 * PARAMS
 *  str [I] Address of string.
 *  max [I] Maximum size of string.
 *
 * RETURNS
 *	Success: TRUE.
 *	Failure: FALSE. Read access to all bytes in string.
 */
BOOL WINAPI IsBadStringPtrA( LPCSTR str, UINT_PTR max )
{
    if (!str) return TRUE;

    __TRY
    {
        volatile const char *p = str;
        while (p != str + max) if (!*p++) break;
    }
    __EXCEPT( badptr_handler )
    {
        TRACE("%p caused page fault during read\n", str);
        return TRUE;
    }
    __ENDTRY
    return FALSE;
}


/***********************************************************************
 *             IsBadStringPtrW   (KERNEL32.@)
 *
 * See IsBadStringPtrA.
 */
BOOL WINAPI IsBadStringPtrW( LPCWSTR str, UINT_PTR max )
{
    if (!str) return TRUE;

    __TRY
    {
        volatile const WCHAR *p = str;
        while (p != str + max) if (!*p++) break;
    }
    __EXCEPT( badptr_handler )
    {
        TRACE("%p caused page fault during read\n", str);
        return TRUE;
    }
    __ENDTRY
    return FALSE;
}
/***********************************************************************
 *           lstrcatA   (KERNEL32.@)
 *           lstrcat    (KERNEL32.@)
 */
LPSTR WINAPI lstrcatA( LPSTR dst, LPCSTR src )
{
    __TRY
    {
        strcat( dst, src );
    }
    __EXCEPT( badptr_handler )
    {
        SetLastError( ERROR_INVALID_PARAMETER );
        return NULL;
    }
    __ENDTRY
    return dst;
}


/***********************************************************************
 *           lstrcatW   (KERNEL32.@)
 */
LPWSTR WINAPI lstrcatW( LPWSTR dst, LPCWSTR src )
{
    __TRY
    {
        strcatW( dst, src );
    }
    __EXCEPT( badptr_handler )
    {
        SetLastError( ERROR_INVALID_PARAMETER );
        return NULL;
    }
    __ENDTRY
    return dst;
}


/***********************************************************************
 *           lstrcpyA   (KERNEL32.@)
 *           lstrcpy    (KERNEL32.@)
 */
LPSTR WINAPI lstrcpyA( LPSTR dst, LPCSTR src )
{
    __TRY
    {
        /* this is how Windows does it */
        memmove( dst, src, strlen(src)+1 );
    }
    __EXCEPT( badptr_handler )
    {
        SetLastError( ERROR_INVALID_PARAMETER );
        return NULL;
    }
    __ENDTRY
    return dst;
}


/***********************************************************************
 *           lstrcpyW   (KERNEL32.@)
 */
LPWSTR WINAPI lstrcpyW( LPWSTR dst, LPCWSTR src )
{
    __TRY
    {
        strcpyW( dst, src );
    }
    __EXCEPT( badptr_handler )
    {
        SetLastError( ERROR_INVALID_PARAMETER );
        return NULL;
    }
    __ENDTRY
    return dst;
}