view src/video/photon/SDL_ph_mouse.c @ 4158:96ce26f24b01 SDL-1.2

Date: Sun, 7 Sep 2008 15:17:00 +0200 From: c2woody@gmx.net Subject: [SDL] SDL 1.2 doube free/pointer zeroing missing Hello, this is about a crash/debug breakage for the current SDL 1.2 source tree (today's svn checkout, same problem in 1.2.13 and before as far as relevant). In some places memory is free()d but the associated pointer is not zeroed, leading to for example double free()s. For me this happened because SDL_StopEventThread() was executed twice (during restart of the subsystems), once for the close down in SDL_VideoQuit() and once at the startup, right at the beginning of SDL_StartEventLoop(). Thus the code SDL_DestroyMutex(SDL_EventQ.lock); (see SDL_events.c) was called twice and executed the SDL_free(mutex); twice as well, leading to a crash (msvc 64bit for which it was noticed). I've tried to check all other occurrences of SDL_free and similar code in msvc, see the attached patch (udiff against revision 4082). Non-windows only codepaths have neither been checked nor touched. Comments/ideas welcome. Attached patch: NULLifies some pointers after they have been free()d.
author Sam Lantinga <slouken@libsdl.org>
date Wed, 12 Nov 2008 17:23:40 +0000
parents d910939febfa
children e49147870aac c121d94672cb a1b03ba2fcd0
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    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

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#include "SDL_mouse.h"
#include "../../events/SDL_events_c.h"
#include "../SDL_cursor_c.h"
#include "SDL_ph_mouse_c.h"

struct WMcursor
{
    PhCursorDef_t *ph_cursor ;
};

void ph_FreeWMCursor(_THIS, WMcursor *cursor)
{
    if (window != NULL)
    {
        SDL_Lock_EventThread();

        if (PtSetResource(window, Pt_ARG_CURSOR_TYPE, Ph_CURSOR_INHERIT, 0) < 0)
        {
            /* TODO: output error msg */
        }

        SDL_Unlock_EventThread();
    }	

    SDL_free(cursor);
}

WMcursor *ph_CreateWMCursor(_THIS, Uint8 *data, Uint8 *mask, int w, int h, int hot_x, int hot_y)
{
    WMcursor* cursor;
    int clen, i;
    unsigned char bit, databit, maskbit;

    /* Allocate and initialize the cursor memory */
    if ((cursor = (WMcursor*)SDL_malloc(sizeof(WMcursor))) == NULL)
    {
        SDL_OutOfMemory();
        return(NULL);
    }
    SDL_memset(cursor,0,sizeof(WMcursor));

    cursor->ph_cursor = (PhCursorDef_t *) SDL_malloc(sizeof(PhCursorDef_t) + 32*4*2);

    if (cursor->ph_cursor == NULL)
    {
        SDL_SetError("ph_CreateWMCursor(): cursor malloc failed !\n");
        return NULL;
    }

    SDL_memset(cursor->ph_cursor,0,(sizeof(PhCursorDef_t) + 32*4*2));

    cursor->ph_cursor->hdr.type =Ph_RDATA_CURSOR;   
    cursor->ph_cursor->size1.x = (short)w;
    cursor->ph_cursor->size1.y = (short)h;
    cursor->ph_cursor->offset1.x = (short)hot_x;
    cursor->ph_cursor->offset1.y = (short)hot_y;
    cursor->ph_cursor->bytesperline1 = (char)w/8;
    cursor->ph_cursor->color1 = Pg_WHITE;
    cursor->ph_cursor->size2.x = (short)w;
    cursor->ph_cursor->size2.y = (short)h;
    cursor->ph_cursor->offset2.x = (short)hot_x;
    cursor->ph_cursor->offset2.y = (short)hot_y;
    cursor->ph_cursor->bytesperline2 = (char)w/8;
    cursor->ph_cursor->color2 = Pg_BLACK;

    clen = (w/8)*h;

    /* Copy the mask and the data to different bitmap planes */
    for (i=0; i<clen; ++i)
    {
        for (bit = 0; bit < 8; bit++)
        {
            databit = data[i] & (1 << bit);
            maskbit = mask[i] & (1 << bit);

            cursor->ph_cursor->images[i] |= (databit == 0) ? maskbit : 0;
            /* If the databit != 0, treat it as a black pixel and
             * ignore the maskbit (can't do an inverted color) */
            cursor->ph_cursor->images[i+clen] |= databit;
        }
    }

    /* #bytes following the hdr struct */
    cursor->ph_cursor->hdr.len =sizeof(PhCursorDef_t) + clen*2 - sizeof(PhRegionDataHdr_t); 

    return (cursor);
}

PhCursorDef_t ph_GetWMPhCursor(WMcursor *cursor)
{
    return (*cursor->ph_cursor);
}

int ph_ShowWMCursor(_THIS, WMcursor* cursor)
{
    PtArg_t args[3];
    int nargs = 0;

    /* Don't do anything if the display is gone */
    if (window == NULL)
    {
        return (0);
    }

    /* looks like photon can't draw mouse cursor in direct mode */
    if ((this->screen->flags & SDL_FULLSCREEN) == SDL_FULLSCREEN)
    {
         /* disable the fake mouse in the fullscreen OpenGL mode */
         if ((this->screen->flags & SDL_OPENGL) == SDL_OPENGL)
         {
             cursor=NULL;
         }
         else
         {
             return (0);
         }
    }

    /* Set the photon cursor, or blank if cursor is NULL */
    if (cursor!=NULL)
    {
        PtSetArg(&args[0], Pt_ARG_CURSOR_TYPE, Ph_CURSOR_BITMAP, 0);
        /* Could set next to any PgColor_t value */
        PtSetArg(&args[1], Pt_ARG_CURSOR_COLOR, Ph_CURSOR_DEFAULT_COLOR , 0);
        PtSetArg(&args[2], Pt_ARG_BITMAP_CURSOR, cursor->ph_cursor, (cursor->ph_cursor->hdr.len + sizeof(PhRegionDataHdr_t)));
        nargs = 3;
    }
    else /* Ph_CURSOR_NONE */
    {
        PtSetArg(&args[0], Pt_ARG_CURSOR_TYPE, Ph_CURSOR_NONE, 0);
        nargs = 1;
    }

    SDL_Lock_EventThread();

    if (PtSetResources(window, nargs, args) < 0 )
    {
        return (0);
    }	

    SDL_Unlock_EventThread();

    return (1);
}


void ph_WarpWMCursor(_THIS, Uint16 x, Uint16 y)
{
    short abs_x, abs_y;

    SDL_Lock_EventThread();
    PtGetAbsPosition( window, &abs_x, &abs_y );
    PhMoveCursorAbs( PhInputGroup(NULL), x + abs_x, y + abs_y );
    SDL_Unlock_EventThread();
}


void ph_CheckMouseMode(_THIS)
{
    /* If the mouse is hidden and input is grabbed, we use relative mode */
    if ( !(SDL_cursorstate & CURSOR_VISIBLE) && (this->input_grab != SDL_GRAB_OFF))
    {
        mouse_relative = 1;
    }
    else
    {
        mouse_relative = 0;
    }
}


void ph_UpdateMouse(_THIS)
{
    PhCursorInfo_t phcursor;
    short abs_x;
    short abs_y;

    /* Lock the event thread, in multi-threading environments */
    SDL_Lock_EventThread();

    /* synchronizing photon mouse cursor position and SDL mouse position, if cursor appears over window. */
    PtGetAbsPosition(window, &abs_x, &abs_y);
    PhQueryCursor(PhInputGroup(NULL), &phcursor);
    if (((phcursor.pos.x >= abs_x) && (phcursor.pos.x <= abs_x + this->screen->w)) &&
        ((phcursor.pos.y >= abs_y) && (phcursor.pos.y <= abs_y + this->screen->h)))
    {
        SDL_PrivateAppActive(1, SDL_APPMOUSEFOCUS);
        SDL_PrivateMouseMotion(0, 0, phcursor.pos.x-abs_x, phcursor.pos.y-abs_y);
    }
    else
    {
        SDL_PrivateAppActive(0, SDL_APPMOUSEFOCUS);
    }

    /* Unlock the event thread, in multi-threading environments */
    SDL_Unlock_EventThread();
}