From: Markus Armbruster <armbru@pond.sub.org>
Date: Mon, 12 Oct 2009 02:18:26 +0000 (-0400)
Subject: Don't intercept tactical and marine missiles targeting planes
X-Git-Tag: v4.3.23~9
X-Git-Url: http://git.pond.sub.org/?p=empserver;a=commitdiff_plain;h=22071b4edb0448bd5b3da73ca7c736315e785b68

Don't intercept tactical and marine missiles targeting planes

Missiles attacking ground targets (sectors, ships or land units) can
be intercepted, missiles targeting planes can't.  Except msl_launch()
checked the missile's capabilities instead of its target, and thus
intercepted missiles that *could* target ground even when they
targeted planes.

This broke the missile interception code's assumption that
interceptors aren't intercepted, and crashed the server through
infinite recursion: tactical abm #1 intercepts, tactical abm #2
intercepts #1, #1 intercepts #2, ...

Same bug in msl_hit() printed "incoming missile" for missiles that
could target ground but do target planes.

Broken in Empire 2.  Bug can't bite with the stock game's planes.
---

diff --git a/src/lib/subs/mslsub.c b/src/lib/subs/mslsub.c
index 30ed82cb2..9bfbf9fc7 100644
--- a/src/lib/subs/mslsub.c
+++ b/src/lib/subs/mslsub.c
@@ -61,7 +61,6 @@ msl_launch(struct plnstr *pp, int type, char *what, coord x, coord y,
     struct shpstr ship;
     struct sctstr sect;
     int sublaunch = 0;
-    struct plchrstr *pcp = plchr + pp->pln_type;
     char *from;
     int dam;
 
@@ -115,16 +114,16 @@ msl_launch(struct plnstr *pp, int type, char *what, coord x, coord y,
     putplane(pp->pln_uid, pp);
     mpr(pp->pln_own, "\tSHWOOOOOSH!  Missile launched!\n");
 
-    if (pcp->pl_flags & P_T)
+    if (type != EF_PLANE)
 	mpr(victim, "Incoming %s missile sighted at %s...\n",
 	    sublaunch ? "sub-launched" : cname(pp->pln_own),
 	    xyas(x, y, victim));
 
-    if ((pcp->pl_flags & P_T && !(pcp->pl_flags & P_MAR))) {
+    if (type == EF_SECTOR || type == EF_LAND) {
 	if (msl_abm_intercept(pp, x, y, sublaunch))
 	    return -1;
     }
-    if (pcp->pl_flags & P_MAR) {
+    if (type == EF_SHIP) {
 	if (shp_missile_defense(x, y, pp->pln_own, pln_def(pp))) {
 	    return -1;
 	}
@@ -139,7 +138,6 @@ int
 msl_hit(struct plnstr *pp, int hardtarget, int type,
 	int news_item, int snews_item, int sublaunch, natid victim)
 {
-    struct plchrstr *pcp = plchr + pp->pln_type;
     int hitchance, hit;
 
     if (nuk_on_plane(pp) >= 0) {
@@ -152,7 +150,7 @@ msl_hit(struct plnstr *pp, int hardtarget, int type,
 	    hit ? "HIT!" : "miss");
     }
 
-    if (pcp->pl_flags & P_T)
+    if (type != EF_PLANE)
 	mpr(victim, "...Incoming %s missile %s\n",
 	    sublaunch ? "" : cname(pp->pln_own),
 	    hit ? "HIT!\n" : "missed\n");