Check ef_type before dereferencing struct empobj

Such manual checking is error prone, but the best we can do right now.

src/lib/commands/look.c

@@ -67,6 +67,9 @@ do_look(short type)
     unsigned char *bitmap;
     int changed = 0;
 
+    if (CANT_HAPPEN(type != EF_LAND && type != EF_SHIP))
+	type = EF_SHIP;
+
     if (!snxtitem(&ni, type, player->argp[1]))
 	return RET_SYN;
     if ((bitmap = malloc((WORLD_X * WORLD_Y) / 8)) == 0) {

src/lib/commands/rada.c

@@ -61,6 +61,9 @@ radar(short type)
     char buf[1024];
     char prompt[80];
 
+    if (CANT_HAPPEN(type != EF_LAND && type != EF_SHIP))
+	type = EF_SHIP;
+
     sprintf(prompt, "Radar from (%s # or sector(s)) : ", ef_nameof(type));
     cp = getstarg(player->argp[1], prompt, buf);
 		      

src/lib/subs/maps.c

@@ -349,6 +349,10 @@ unit_map(int unit_type, int uid, struct nstr_sect *nsp, char *originp)
     struct range range;
     char *name;
 
+    if (CANT_HAPPEN((ef_flags(unit_type) & (EFF_OWNER | EFF_XY))
+		    != (EFF_OWNER | EFF_XY)))
+	return RET_FAIL;
+
     if (!get_empobj(unit_type, uid, &unit))
 	return RET_FAIL;
     if (!player->owner || unit.gen.own == 0)

src/lib/subs/mission.c

@@ -622,6 +622,9 @@ perform_mission(coord x, coord y, natid victim, struct emp_qelem *list,
 	    else
 		emp_insque(&plp->queue, &bombers);
 	    plane_owner = plp->plane.pln_own;
+	} else {
+	    CANT_REACH();
+	    break;
 	}
     }
     if (!QEMPTY(&missiles)) {
@@ -1327,6 +1330,8 @@ air_defense(coord x, coord y, natid victim, struct emp_qelem *bomb_list,
 	    next = qp->q_forw;
 	    glp = (struct genlist *)qp;
 	    gp = glp->thing;
+	    if (CANT_HAPPEN(gp->ef_type != EF_PLANE))
+		break;
 
 	    dist = mapdist(x, y, gp->x, gp->y);
 

src/lib/subs/nxtitem.c

@@ -72,26 +72,33 @@ nxtitem(struct nstr_item *np, void *ptr)
 	case NS_ALL:
 	    break;
 	case NS_DIST:
+	    if (CANT_HAPPEN(!(ef_flags(np->type) & EFF_XY)))
+		return 0;
 	    if (!xyinrange(gp->x, gp->y, &np->range)) {
 		selected = 0;
 		break;
 	    }
-	    np->curdist = mapdist((int)gp->x, (int)gp->y,
+	    np->curdist = mapdist(gp->x, gp->y, np->cx, np->cy);
-				  (int)np->cx, (int)np->cy);
 	    if (np->curdist > np->dist)
 		selected = 0;
 	    break;
 	case NS_AREA:
+	    if (CANT_HAPPEN(!(ef_flags(np->type) & EFF_XY)))
+		return 0;
 	    if (!xyinrange(gp->x, gp->y, &np->range))
 		selected = 0;
 	    if (gp->x == np->range.hx || gp->y == np->range.hy)
 		selected = 0;
 	    break;
 	case NS_XY:
+	    if (CANT_HAPPEN(!(ef_flags(np->type) & EFF_XY)))
+		return 0;
 	    if (xnorm(gp->x) != np->cx || ynorm(gp->y) != np->cy)
 		selected = 0;
 	    break;
 	case NS_GROUP:
+	    if (CANT_HAPPEN(!(ef_flags(np->type) & EFF_GROUP)))
+		return 0;
 	    if (np->group != gp->group)
 		selected = 0;
 	    break;

src/lib/subs/unitsub.c

@@ -45,16 +45,20 @@ unit_list(struct emp_qelem *unit_list)
     struct emp_qelem *qp;
     struct emp_qelem *next;
     struct ulist *ulp;
+    int type;
     struct empobj *unit;
     struct lndstr *lnd;
     struct shpstr *shp;
 
-    CANT_HAPPEN(QEMPTY(unit_list));
+    if (CANT_HAPPEN(QEMPTY(unit_list)))
-
+	return;
     qp = unit_list->q_back;
     ulp = (struct ulist *)qp;
+    type = ulp->unit.ef_type;
+    if (CANT_HAPPEN(type != EF_LAND && type != EF_SHIP))
+	return;
 
-    if (ulp->unit.ef_type == EF_LAND)
+    if (type == EF_LAND)
 	pr("lnd#     land type       x,y    a  eff  sh gun xl  mu tech retr fuel\n");
     else
         pr("shp#     ship type       x,y   fl  eff mil  sh gun pn he xl ln mob tech\n");
@@ -65,12 +69,14 @@ unit_list(struct emp_qelem *unit_list)
 	lnd = &ulp->unit.land;
 	shp = &ulp->unit.ship;
 	unit = &ulp->unit.gen;
+	if (CANT_HAPPEN(type != unit->ef_type))
+	    continue;
 	pr("%4d ", unit->uid);
 	pr("%-16.16s ", emp_obj_chr_name(unit));
 	prxy("%4d,%-4d ", unit->x, unit->y, unit->own);
 	pr("%1.1s", &unit->group);
 	pr("%4d%%", unit->effic);
-	if (unit->ef_type == EF_LAND) {
+	if (type == EF_LAND) {
 	    pr("%4d", lnd->lnd_item[I_SHELL]);
 	    pr("%4d", lnd->lnd_item[I_GUN]);
 	    count_land_planes(lnd);
@@ -88,7 +94,7 @@ unit_list(struct emp_qelem *unit_list)
 	}
 	pr("%4d", unit->mobil);
 	pr("%4d", unit->tech);
-	if (unit->ef_type == EF_LAND) {
+	if (type == EF_LAND) {
 	    pr("%4d%%", lnd->lnd_retreat);
 	    pr("%5d", lnd->lnd_fuel);
 	}
@@ -108,6 +114,9 @@ unit_put(struct emp_qelem *list, natid actor)
     while (qp != list) {
 	ulp = (struct ulist *)qp;
 	unit = &ulp->unit.gen;
+	if (CANT_HAPPEN(unit->ef_type != EF_LAND
+			&& unit->ef_type != EF_SHIP))
+	    continue;
 	if (actor) {
 	    mpr(actor, "%s stopped at %s\n", obj_nameof(unit),
 		xyas(unit->x, unit->y, unit->own));
@@ -137,6 +146,9 @@ unit_path(int together, struct empobj *unit, char *buf)
     double dummy;
     int mtype;
 
+    if (CANT_HAPPEN(unit->ef_type != EF_LAND && unit->ef_type != EF_SHIP))
+	return NULL;
+
     if (!sarg_xy(buf, &destx, &desty))
 	return 0;
     if (!together) {
@@ -182,6 +194,8 @@ unit_view(struct emp_qelem *list)
     for (qp = list->q_back; qp != list; qp = next) {
 	next = qp->q_back;
 	ulp = (struct ulist *)qp;
+	if (CANT_HAPPEN(!(ef_flags(ulp->unit.ef_type) & EFF_XY)))
+	    continue;
 	getsect(ulp->unit.gen.x, ulp->unit.gen.y, &sect);
 	if (ulp->unit.ef_type == EF_SHIP) {
 	    if (((struct mchrstr *)ulp->chrp)->m_flags & M_FOOD)

src/lib/update/nxtitemp.c

@@ -67,26 +67,33 @@ nxtitemp(struct nstr_item *np)
 	case NS_ALL:
 	    break;
 	case NS_DIST:
+	    if (CANT_HAPPEN(!(ef_flags(np->type) & EFF_XY)))
+		return 0;
 	    if (!xyinrange(gp->x, gp->y, &np->range)) {
 		selected = 0;
 		break;
 	    }
-	    np->curdist = mapdist((int)gp->x, (int)gp->y,
+	    np->curdist = mapdist(gp->x, gp->y, np->cx, np->cy);
-				  (int)np->cx, (int)np->cy);
 	    if (np->curdist > np->dist)
 		selected = 0;
 	    break;
 	case NS_AREA:
+	    if (CANT_HAPPEN(!(ef_flags(np->type) & EFF_XY)))
+		return 0;
 	    if (!xyinrange(gp->x, gp->y, &np->range))
 		selected = 0;
 	    if (gp->x == np->range.hx || gp->y == np->range.hy)
 		selected = 0;
 	    break;
 	case NS_XY:
+	    if (CANT_HAPPEN(!(ef_flags(np->type) & EFF_XY)))
+		return 0;
 	    if (xnorm(gp->x) != np->cx || ynorm(gp->y) != np->cy)
 		selected = 0;
 	    break;
 	case NS_GROUP:
+	    if (CANT_HAPPEN(!(ef_flags(np->type) & EFF_GROUP)))
+		return 0;
 	    if (np->group != gp->group)
 		selected = 0;
 	    break;