add support for running sdl programs

Makefile

@@ -3,10 +3,15 @@
 
 include config_rs97.mk
 
-SRC = st.c keyboard.c font.c
+SRC = st.c keyboard.c font.c msg_queue.c
 OBJ = ${SRC:.c=.o}
 
-all: options st
+all: options st libst-preload.so sdl_test
+
+libst-preload.so: st-preload.o msg_queue.o
+	${CC} -shared -o $@ $^
+
+sdl_test: sdl_test.o
 
 options:
 	@echo st build options:

msg_queue.c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ipc.h>
+#include <sys/msg.h>
+#include <errno.h>
+
+#include "msg_queue.h"
+
+queue_t queue_create() {
+	key_t keyval = ftok(QUEUE_NAME, QUEUE_ID);
+	return msgget( keyval, IPC_CREAT | 0660 );
+}
+
+queue_t queue_open() {
+	key_t keyval = ftok(QUEUE_NAME, QUEUE_ID);
+	return msgget( keyval, 0660 );
+}
+
+int queue_send(queue_t qid, message_t *message) {
+	int length = sizeof(message_t) - sizeof(long);        
+
+	return msgsnd( qid, message, length, 0);
+}
+
+int queue_read(queue_t qid, long type, message_t *message) {
+	int length = sizeof(message_t) - sizeof(long);        
+
+	return msgrcv( qid, message, length, type,  0);
+}
+
+int queue_peek(queue_t qid, long type) {
+	if(msgrcv( qid, NULL, 0, type,  IPC_NOWAIT) == -1) {
+		if(errno == E2BIG) return 1;
+	}
+
+	return 0;
+}
+
+int queue_remove(queue_t qid) {
+	return msgctl(qid, IPC_RMID, 0);
+}
+

msg_queue.h

@@ -0,0 +1,23 @@
+#ifndef __MSG_QUEUE__
+#define __MSG_QUEUE__
+
+#define QUEUE_NAME "st-sdl"
+#define QUEUE_ID 1
+
+typedef struct {
+	long type;
+	long data;
+} message_t;
+
+typedef int queue_t;
+
+enum { MSG_CLIENT=1, MSG_SERVER, MSG_REQUEST_SHUTDOWN, MSG_SHUTDOWN, MSG_REQUEST_INIT };
+
+queue_t queue_create();
+queue_t queue_open();
+int queue_send(queue_t qid, message_t *message);
+int queue_read(queue_t qid, long type, message_t *message);
+int queue_peek(queue_t qid, long type);
+int queue_remove(queue_t qid);
+
+#endif

sdl_test.c

@@ -0,0 +1,38 @@
+#include <SDL/SDL.h>
+
+int main(int argc, char** argv) {
+	SDL_Init(SDL_INIT_VIDEO);
+	printf("Testing SDL\n");
+
+	SDL_Surface* screen = SDL_SetVideoMode(320, 240, 16, SDL_HWSURFACE | SDL_DOUBLEBUF);
+
+	int quit = 0;
+	while( !quit ){
+		SDL_Event event;
+		while( SDL_PollEvent( &event ) ){
+
+			switch( event.type ){
+				case SDL_KEYDOWN:
+				case SDL_KEYUP:
+					quit = 1;
+					break;
+				case SDL_QUIT:
+					quit = 1;
+					break;
+				default:
+					break;
+			}
+
+		}
+		SDL_Rect rect;
+		rect.x = rand() % screen->w;
+		rect.y = rand() % screen->h;
+		rect.w = rand() % (screen->w - rect.x);
+		rect.h = rand() % (screen->h - rect.y);
+		SDL_FillRect(screen, &rect, SDL_MapRGB(screen->format, rand() % 255, rand() % 255, rand() % 255));
+		SDL_Flip(screen);
+		SDL_Delay(1000 / 60);
+	}
+
+	SDL_Quit();
+}

st-preload.c

@@ -0,0 +1,37 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <dlfcn.h>
+
+#include "msg_queue.h"
+
+static int sdl_init_was_called = 0;
+static int (*real_SDL_Init)(int) = NULL;
+
+int SDL_Init(int flags) {
+	if (sdl_init_was_called == 0) {
+		queue_t qid = queue_open();
+		if(qid != -1) {
+			message_t message = {.type = MSG_CLIENT, .data = MSG_REQUEST_SHUTDOWN };
+			queue_send(qid, &message);
+			queue_read(qid, MSG_SERVER, &message);
+		}
+
+		real_SDL_Init = dlsym(RTLD_NEXT, "SDL_Init");
+		sdl_init_was_called = 1;
+	}
+	return real_SDL_Init(flags);
+}
+
+void __attribute__((destructor)) preload_cleanup() {
+	if(sdl_init_was_called) {
+		queue_t qid = queue_open();
+		if(qid != -1) {
+			message_t message = {.type = MSG_CLIENT, .data = MSG_REQUEST_INIT };
+			queue_send(qid, &message);
+		}
+	}
+}
+