view src/video/caca/SDL_cacavideo.c @ 4355:9b464226e541 SDL-1.2

Fixed bug #855 Ludwig Nussel 2009-10-18 06:31:52 PDT an mprotect call was added to fix bug 528. However that results in a buffer that allows writing and code execution. Ie the no-execute security features of modern operating systems are defeated this way. Two mprotect calls are needed. One to make the buffer executable but not writeable when done and another one to make the buffer writeable again if the content needs to be changed.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 18 Oct 2009 17:31:37 +0000
parents d1c0ac95d023
children
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 2003  Sam Hocevar

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Hocevar
    sam@zoy.org
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id: libsdl-1.2.11-libcaca.patch,v 1.1 2006/09/18 16:06:06 mr_bones_ Exp $";
#endif

/* libcaca based SDL video driver implementation.
*/

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>


#include "SDL.h"
#include "SDL_error.h"
#include "SDL_video.h"
#include "SDL_mouse.h"
#include "../SDL_sysvideo.h"
#include "../SDL_pixels_c.h"
#include "../../events/SDL_events_c.h"

#include "SDL_cacavideo.h"
#include "SDL_cacaevents_c.h"

#include <caca.h>
#ifdef CACA_API_VERSION_1
#include <caca0.h>
#endif

/* Initialization/Query functions */
static int Caca_VideoInit(_THIS, SDL_PixelFormat *vformat);
static SDL_Rect **Caca_ListModes(_THIS, SDL_PixelFormat *format, Uint32 flags);
static SDL_Surface *Caca_SetVideoMode(_THIS, SDL_Surface *current, int width, int height, int bpp, Uint32 flags);
static void Caca_VideoQuit(_THIS);

/* Hardware surface functions */
static int Caca_AllocHWSurface(_THIS, SDL_Surface *surface);
static int Caca_LockHWSurface(_THIS, SDL_Surface *surface);
static int Caca_FlipHWSurface(_THIS, SDL_Surface *surface);
static void Caca_UnlockHWSurface(_THIS, SDL_Surface *surface);
static void Caca_FreeHWSurface(_THIS, SDL_Surface *surface);

/* Cache the VideoDevice struct */
static struct SDL_VideoDevice *local_this;

/* libcaca driver bootstrap functions */

static int Caca_Available(void)
{
	return 1; /* Always available ! */
}

static void Caca_DeleteDevice(SDL_VideoDevice *device)
{
	free(device->hidden);
	free(device);
}
static SDL_VideoDevice *Caca_CreateDevice(int devindex)
{
	SDL_VideoDevice *device;

	/* Initialize all variables that we clean on shutdown */
	device = (SDL_VideoDevice *)malloc(sizeof(SDL_VideoDevice));
	if ( device ) {
		memset(device, 0, (sizeof *device));
		device->hidden = (struct SDL_PrivateVideoData *)
				malloc((sizeof *device->hidden));
	}
	if ( (device == NULL) || (device->hidden == NULL) ) {
		SDL_OutOfMemory();
		if ( device ) {
			free(device);
		}
		return(0);
	}
	memset(device->hidden, 0, (sizeof *device->hidden));

	/* Set the function pointers */
	device->VideoInit = Caca_VideoInit;
	device->ListModes = Caca_ListModes;
	device->SetVideoMode = Caca_SetVideoMode;
	device->CreateYUVOverlay = NULL;
	device->SetColors = NULL;
	device->UpdateRects = NULL;
	device->VideoQuit = Caca_VideoQuit;
	device->AllocHWSurface = Caca_AllocHWSurface;
	device->CheckHWBlit = NULL;
	device->FillHWRect = NULL;
	device->SetHWColorKey = NULL;
	device->SetHWAlpha = NULL;
	device->LockHWSurface = Caca_LockHWSurface;
	device->UnlockHWSurface = Caca_UnlockHWSurface;
	device->FlipHWSurface = NULL;
	device->FreeHWSurface = Caca_FreeHWSurface;
	device->SetCaption = NULL;
	device->SetIcon = NULL;
	device->IconifyWindow = NULL;
	device->GrabInput = NULL;
	device->GetWMInfo = NULL;
	device->InitOSKeymap = Caca_InitOSKeymap;
	device->PumpEvents = Caca_PumpEvents;

	device->free = Caca_DeleteDevice;

	return device;
}

VideoBootStrap CACA_bootstrap = {
	"caca", "Color ASCII Art Library",
	Caca_Available, Caca_CreateDevice
};

int Caca_VideoInit(_THIS, SDL_PixelFormat *vformat)
{
	int i;

	/* Initialize all variables that we clean on shutdown */
	for ( i=0; i<SDL_NUMMODES; ++i ) {
		SDL_modelist[i] = malloc(sizeof(SDL_Rect));
		SDL_modelist[i]->x = SDL_modelist[i]->y = 0;
	}
	/* Modes sorted largest to smallest */
	SDL_modelist[0]->w = 1024; SDL_modelist[0]->h = 768;
	SDL_modelist[1]->w = 800; SDL_modelist[1]->h = 600;
	SDL_modelist[2]->w = 640; SDL_modelist[2]->h = 480;
	SDL_modelist[3]->w = 320; SDL_modelist[3]->h = 400;
	SDL_modelist[4]->w = 320; SDL_modelist[4]->h = 240;
	SDL_modelist[5]->w = 320; SDL_modelist[5]->h = 200;
	SDL_modelist[6] = NULL;

	Caca_mutex = SDL_CreateMutex();

	/* Initialize the library */
	if ( caca_init() != 0 ) {
		SDL_SetError("Unable to initialize libcaca");
		return(-1);
	}

	/* Initialize private variables */
	Caca_lastkey = 0;
	Caca_bitmap = NULL;
	Caca_buffer = NULL;

	local_this = this;

	/* Determine the screen depth (use default 8-bit depth) */
	vformat->BitsPerPixel = 8;
	vformat->BytesPerPixel = 1;

	/* We're done! */
	return(0);
}

SDL_Rect **Caca_ListModes(_THIS, SDL_PixelFormat *format, Uint32 flags)
{
     if(format->BitsPerPixel != 8)
 		return NULL;

	 if ( flags & SDL_FULLSCREEN ) {
		 return SDL_modelist;
	 } else {
		 return (SDL_Rect **) -1;
	 }
}

/* Various screen update functions available */
static void Caca_DirectUpdate(_THIS, int numrects, SDL_Rect *rects);

SDL_Surface *Caca_SetVideoMode(_THIS, SDL_Surface *current,
				int width, int height, int bpp, Uint32 flags)
{
	if ( Caca_buffer ) {
		free( Caca_buffer );
		Caca_buffer = NULL;
	}

	if ( Caca_bitmap ) {
		caca_free_bitmap( Caca_bitmap );
		Caca_bitmap = NULL;
	}

	Caca_buffer = malloc(2 * ((width + 15) & ~15) * height);
	if ( ! Caca_buffer ) {
		SDL_SetError("Couldn't allocate buffer for requested mode");
		return(NULL);
	}

	memset(Caca_buffer, 0, 2 * ((width + 15) & ~15) * height);

	/* Allocate the new pixel format for the screen */
	if ( ! SDL_ReallocFormat(current, 16, 0xf800, 0x07e0, 0x001f, 0) ) {
		return(NULL);
	}

	/* Set up the new mode framebuffer */
	current->flags = SDL_FULLSCREEN;
	Caca_w = current->w = width;
	Caca_h = current->h = height;
	current->pitch = 2 * ((width + 15) & ~15);
	current->pixels = Caca_buffer;

	/* Create the libcaca bitmap */
	Caca_bitmap = caca_create_bitmap( 16, width, height, current->pitch, 0xf800, 0x07e0, 0x001f, 0x0000 );
	if ( ! Caca_bitmap ) {
		SDL_SetError("Couldn't allocate libcaca bitmap");
		return(NULL);
	}

	/* Set the blit function */
	this->UpdateRects = Caca_DirectUpdate;

	/* We're done */
	return(current);
}

/* We don't actually allow hardware surfaces other than the main one */
static int Caca_AllocHWSurface(_THIS, SDL_Surface *surface)
{
	return(-1);
}
static void Caca_FreeHWSurface(_THIS, SDL_Surface *surface)
{
	return;
}

/* We need to wait for vertical retrace on page flipped displays */
static int Caca_LockHWSurface(_THIS, SDL_Surface *surface)
{
	/* TODO ? */
	return(0);
}
static void Caca_UnlockHWSurface(_THIS, SDL_Surface *surface)
{
	return;
}

/* FIXME: How is this done with libcaca? */
static int Caca_FlipHWSurface(_THIS, SDL_Surface *surface)
{
	SDL_mutexP(Caca_mutex);
	caca_refresh();
	SDL_mutexV(Caca_mutex);
	return(0);
}

static void Caca_DirectUpdate(_THIS, int numrects, SDL_Rect *rects)
{
	SDL_mutexP(Caca_mutex);
	caca_draw_bitmap( 0, 0, caca_get_width() - 1, caca_get_height() - 1,
			  Caca_bitmap, Caca_buffer );
	caca_refresh();
	SDL_mutexV(Caca_mutex);
	return;
}

/* Note:  If we are terminated, this could be called in the middle of
   another SDL video routine -- notably UpdateRects.
*/
void Caca_VideoQuit(_THIS)
{
	int i;

	/* Free video mode lists */
	for ( i=0; i<SDL_NUMMODES; ++i ) {
		if ( SDL_modelist[i] != NULL ) {
			free(SDL_modelist[i]);
			SDL_modelist[i] = NULL;
		}
	}

	if ( Caca_bitmap ) {
		caca_free_bitmap( Caca_bitmap );
		Caca_bitmap = NULL;
	}

	caca_end();

	SDL_DestroyMutex(Caca_mutex);
}