view test/testwm.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 67fc81efcfc3
children c121d94672cb 14195cfdb66e
line wrap: on
line source


/* Test out the window manager interaction functions */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "SDL.h"

/* Is the cursor visible? */
static int visible = 1;

static Uint8  video_bpp;
static Uint32 video_flags;

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void quit(int rc)
{
	SDL_Quit();
	exit(rc);
}

int SetVideoMode(int w, int h)
{
	SDL_Surface *screen;
	int i;
	Uint8 *buffer;
	SDL_Color palette[256];

	screen = SDL_SetVideoMode(w, h, video_bpp, video_flags);
	if (  screen == NULL ) {
		fprintf(stderr, "Couldn't set %dx%dx%d video mode: %s\n",
					w, h, video_bpp, SDL_GetError());
		return(-1);
	}
	printf("Running in %s mode\n", screen->flags & SDL_FULLSCREEN ?
						"fullscreen" : "windowed");

	/* Set the surface pixels and refresh! */
	for ( i=0; i<256; ++i ) {
		palette[i].r = 255-i;
		palette[i].g = 255-i;
		palette[i].b = 255-i;
	}
	SDL_SetColors(screen, palette, 0, 256);
	if ( SDL_LockSurface(screen) < 0 ) {
		fprintf(stderr, "Couldn't lock display surface: %s\n",
							SDL_GetError());
		return(-1);
	}
	buffer = (Uint8 *)screen->pixels;
	for ( i=0; i<screen->h; ++i ) {
		memset(buffer,(i*255)/screen->h,
				screen->w*screen->format->BytesPerPixel);
		buffer += screen->pitch;
	}
	SDL_UnlockSurface(screen);
	SDL_UpdateRect(screen, 0, 0, 0, 0);

	return(0);
}

SDL_Surface *LoadIconSurface(char *file, Uint8 **maskp)
{
	SDL_Surface *icon;
	Uint8       *pixels;
	Uint8       *mask;
	int          mlen, i, j;

	*maskp = NULL;

	/* Load the icon surface */
	icon = SDL_LoadBMP(file);
	if ( icon == NULL ) {
		fprintf(stderr, "Couldn't load %s: %s\n", file, SDL_GetError());
		return(NULL);
	}

	/* Check width and height 
	if ( (icon->w%8) != 0 ) {
		fprintf(stderr, "Icon width must be a multiple of 8!\n");
		SDL_FreeSurface(icon);
		return(NULL);
	}
*/
    
    
	if ( icon->format->palette == NULL ) {
		fprintf(stderr, "Icon must have a palette!\n");
		SDL_FreeSurface(icon);
		return(NULL);
	}

	/* Set the colorkey */
	SDL_SetColorKey(icon, SDL_SRCCOLORKEY, *((Uint8 *)icon->pixels));

	/* Create the mask */
	pixels = (Uint8 *)icon->pixels;
	printf("Transparent pixel: (%d,%d,%d)\n",
				icon->format->palette->colors[*pixels].r,
				icon->format->palette->colors[*pixels].g,
				icon->format->palette->colors[*pixels].b);
	mlen = (icon->w*icon->h + 7) / 8;
	mask = (Uint8 *)malloc(mlen);
	if ( mask == NULL ) {
		fprintf(stderr, "Out of memory!\n");
		SDL_FreeSurface(icon);
		return(NULL);
	}
	memset(mask, 0, mlen);
	for ( i=0; i < icon->h; i++)
        for (j=0; j < icon->w; j++) {
            int pindex = i * icon->pitch + j;
            int mindex = i * icon->w + j;
            if ( pixels[pindex] != *pixels )
                mask[mindex>>3] |= 1 << (7 - (mindex & 7));
        }
	*maskp = mask;
	return(icon);
}

void HotKey_ToggleFullScreen(void)
{
	SDL_Surface *screen;

	screen = SDL_GetVideoSurface();
	if ( SDL_WM_ToggleFullScreen(screen) ) {
		printf("Toggled fullscreen mode - now %s\n",
		    (screen->flags&SDL_FULLSCREEN) ? "fullscreen" : "windowed");
	} else {
		printf("Unable to toggle fullscreen mode\n");
		video_flags ^= SDL_FULLSCREEN;
		SetVideoMode(screen->w, screen->h);
	}
}

void HotKey_ToggleGrab(void)
{
	SDL_GrabMode mode;

	printf("Ctrl-G: toggling input grab!\n");
	mode = SDL_WM_GrabInput(SDL_GRAB_QUERY);
	if ( mode == SDL_GRAB_ON ) {
		printf("Grab was on\n");
	} else {
		printf("Grab was off\n");
	}
	mode = SDL_WM_GrabInput(mode ? SDL_GRAB_OFF : SDL_GRAB_ON);
	if ( mode == SDL_GRAB_ON ) {
		printf("Grab is now on\n");
	} else {
		printf("Grab is now off\n");
	}
}

void HotKey_Iconify(void)
{
	printf("Ctrl-Z: iconifying window!\n");
	SDL_WM_IconifyWindow();
}

void HotKey_Quit(void)
{
	SDL_Event event;

	printf("Posting internal quit request\n");
	event.type = SDL_USEREVENT;
	SDL_PushEvent(&event);
}

int SDLCALL FilterEvents(const SDL_Event *event)
{
	static int reallyquit = 0;

	switch (event->type) {

		case SDL_ACTIVEEVENT:
			/* See what happened */
			printf("App %s ",
				event->active.gain ? "gained" : "lost");
			if ( event->active.state & SDL_APPACTIVE )
				printf("active ");
			if ( event->active.state & SDL_APPINPUTFOCUS )
				printf("input ");
			if ( event->active.state & SDL_APPMOUSEFOCUS )
				printf("mouse ");
			printf("focus\n");

			/* See if we are iconified or restored */
			if ( event->active.state & SDL_APPACTIVE ) {
				printf("App has been %s\n",
					event->active.gain ?
						 "restored" : "iconified");
			}
			return(0);

		/* We want to toggle visibility on buttonpress */
		case SDL_MOUSEBUTTONDOWN:
		case SDL_MOUSEBUTTONUP:
			if ( event->button.state == SDL_PRESSED ) {
				visible = !visible;
				SDL_ShowCursor(visible);
			}
			printf("Mouse button %d has been %s\n",
				event->button.button,
				(event->button.state == SDL_PRESSED) ?
						"pressed" : "released");
			return(0);

		/* Show relative mouse motion */
		case SDL_MOUSEMOTION:
#if 0
			printf("Mouse motion: {%d,%d} (%d,%d)\n",
				event->motion.x, event->motion.y,
				event->motion.xrel, event->motion.yrel);
#endif
			return(0);

		case SDL_KEYDOWN:
			if ( event->key.keysym.sym == SDLK_ESCAPE ) {
				HotKey_Quit();
			}
			if ( (event->key.keysym.sym == SDLK_g) &&
			     (event->key.keysym.mod & KMOD_CTRL) ) {
				HotKey_ToggleGrab();
			}
			if ( (event->key.keysym.sym == SDLK_z) &&
			     (event->key.keysym.mod & KMOD_CTRL) ) {
				HotKey_Iconify();
			}
			if ( (event->key.keysym.sym == SDLK_RETURN) &&
			     (event->key.keysym.mod & KMOD_ALT) ) {
				HotKey_ToggleFullScreen();
			}
			return(0);

		/* Pass the video resize event through .. */
		case SDL_VIDEORESIZE:
			return(1);

		/* This is important!  Queue it if we want to quit. */
		case SDL_QUIT:
			if ( ! reallyquit ) {
				reallyquit = 1;
				printf("Quit requested\n");
				return(0);
			}
			printf("Quit demanded\n");
			return(1);

		/* This will never happen because events queued directly
		   to the event queue are not filtered.
		 */
		case SDL_USEREVENT:
			return(1);

		/* Drop all other events */
		default:
			return(0);
	}
}

int main(int argc, char *argv[])
{
	SDL_Event event;
	char *title;
	SDL_Surface *icon;
	Uint8 *icon_mask;
	int parsed;
	int w, h;

	if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
		fprintf(stderr,
			"Couldn't initialize SDL: %s\n", SDL_GetError());
		return(1);
	}

	/* Check command line arguments */
	w = 640;
	h = 480;
	video_bpp = 8;
	video_flags = SDL_SWSURFACE;
	parsed = 1;
	while ( parsed ) {
		if ( (argc >= 2) && (strcmp(argv[1], "-fullscreen") == 0) ) {
			video_flags |= SDL_FULLSCREEN;
			argc -= 1;
			argv += 1;
		} else
		if ( (argc >= 2) && (strcmp(argv[1], "-resize") == 0) ) {
			video_flags |= SDL_RESIZABLE;
			argc -= 1;
			argv += 1;
		} else
		if ( (argc >= 2) && (strcmp(argv[1], "-noframe") == 0) ) {
			video_flags |= SDL_NOFRAME;
			argc -= 1;
			argv += 1;
		} else
		if ( (argc >= 3) && (strcmp(argv[1], "-width") == 0) ) {
			w = atoi(argv[2]);
			argc -= 2;
			argv += 2;
		} else
		if ( (argc >= 3) && (strcmp(argv[1], "-height") == 0) ) {
			h = atoi(argv[2]);
			argc -= 2;
			argv += 2;
		} else
		if ( (argc >= 3) && (strcmp(argv[1], "-bpp") == 0) ) {
			video_bpp = atoi(argv[2]);
			argc -= 2;
			argv += 2;
		} else {
			parsed = 0;
		}
	}

	/* Set the icon -- this must be done before the first mode set */
	icon = LoadIconSurface("icon.bmp", &icon_mask);
	if ( icon != NULL ) {
		SDL_WM_SetIcon(icon, icon_mask);
	}
	if ( icon_mask != NULL )
		free(icon_mask);

	/* Set the title bar */
	if ( argv[1] == NULL )
		title = "Testing  1.. 2.. 3...";
	else
		title = argv[1];
	SDL_WM_SetCaption(title, "testwm");

	/* See if it's really set */
	SDL_WM_GetCaption(&title, NULL);
	if ( title )
		printf("Title was set to: %s\n", title);
	else
		printf("No window title was set!\n");

	/* Initialize the display */
	if ( SetVideoMode(w, h) < 0 ) {
		quit(1);
	}

	/* Set an event filter that discards everything but QUIT */
	SDL_SetEventFilter(FilterEvents);

	/* Ignore key up events, they don't even get filtered */
	SDL_EventState(SDL_KEYUP, SDL_IGNORE);

	/* Loop, waiting for QUIT */
	while ( SDL_WaitEvent(&event) ) {
		switch (event.type) {
			case SDL_VIDEORESIZE:
				printf("Got a resize event: %dx%d\n",
				       event.resize.w, event.resize.h);
				SetVideoMode(event.resize.w, event.resize.h);
				break;
			case SDL_USEREVENT:
				printf("Handling internal quit request\n");
				/* Fall through to the quit handler */
			case SDL_QUIT:
				printf("Bye bye..\n");
				quit(0);
			default:
				/* This should never happen */
				printf("Warning: Event %d wasn't filtered\n",
								event.type);
				break;
		}
	}
	printf("SDL_WaitEvent() error: %s\n", SDL_GetError());
	SDL_Quit();
	return(255);
}