view test/testloadso.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 f1699aecb65d
children 2c835d58faad
line wrap: on
line source


/* Test program to test dynamic loading with the loadso subsystem. 
*/

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

#include "SDL.h"

typedef int (*fntype)(const char *);

int main(int argc, char *argv[])
{
	int retval = 0;
	int hello = 0;
	const char *libname = NULL;
	const char *symname = NULL;
	void *lib = NULL;
	fntype fn = NULL;

	if (argc != 3) {
		const char *app = argv[0];
		fprintf(stderr, "USAGE: %s <library> <functionname>\n", app);
		fprintf(stderr, "       %s --hello <lib with puts()>\n", app);
		return 1;
	}

	/* Initialize SDL */
	if ( SDL_Init(0) < 0 ) {
		fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
		return 2;
	}

	if (strcmp(argv[1], "--hello") == 0) {
		hello = 1;
		libname = argv[2];
		symname = "puts";
	} else {
		libname = argv[1];
		symname = argv[2];
	}

	lib = SDL_LoadObject(libname);
        if (lib == NULL) {
		fprintf(stderr, "SDL_LoadObject('%s') failed: %s\n",
		        libname, SDL_GetError());
		retval = 3;
	} else {
		fn = (fntype) SDL_LoadFunction(lib, symname);
		if (fn == NULL) {
			fprintf(stderr, "SDL_LoadFunction('%s') failed: %s\n",
			        symname, SDL_GetError());
			retval = 4;
		} else {
			printf("Found %s in %s at %p\n", symname, libname, fn);
			if (hello) {
				printf("Calling function...\n");
				fflush(stdout);
				fn("     HELLO, WORLD!\n");
				printf("...apparently, we survived.  :)\n");
				printf("Unloading library...\n");
				fflush(stdout);
			}
		}
		SDL_UnloadObject(lib);
	}
	SDL_Quit();
	return(0);
}