From 9d745dbd2106503523c5de207dd4c6890028e61a Mon Sep 17 00:00:00 2001
From: Elizabeth Myers <elizabeth@interlinked.me>
Date: Sat, 20 Apr 2013 01:07:55 -0500
Subject: [PATCH] Implement kill-cancelling hook.

With this comes an example module to block the killing of services.

NOTE: this will not cancel remote kills. Those are still accepted, per
the TS 6 specification.
---
 extensions/Makefile.in        |  1 +
 extensions/m_nokillservices.c | 50 +++++++++++++++++++++++++++++++++++
 include/hook.h                |  1 +
 modules/core/m_kill.c         | 19 ++++++++++++-
 4 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 extensions/m_nokillservices.c

diff --git a/extensions/Makefile.in b/extensions/Makefile.in
index 7606d1f5..2609f59d 100644
--- a/extensions/Makefile.in
+++ b/extensions/Makefile.in
@@ -69,6 +69,7 @@ SRCS =                          \
   m_findforwards.c		\
   m_identify.c			\
   m_mkpasswd.c                  \
+  m_nokillservices.c		\
   m_ojoin.c			\
   m_olist.c			\
   m_okick.c			\
diff --git a/extensions/m_nokillservices.c b/extensions/m_nokillservices.c
new file mode 100644
index 00000000..3446ec83
--- /dev/null
+++ b/extensions/m_nokillservices.c
@@ -0,0 +1,50 @@
+/*
+ * Stop services kills
+ * Well, it won't stop them all, unless this is loaded on all servers.
+ *
+ * Copyright (C) 2013 Elizabeth Myers. All rights reserved.
+ * Licensed under the WTFPLv2
+ */
+
+#include "stdinc.h"
+#include "modules.h"
+#include "hook.h"
+#include "client.h"
+#include "ircd.h"
+#include "send.h"
+#include "hash.h"
+#include "s_conf.h"
+#include "s_user.h"
+#include "s_serv.h"
+#include "numeric.h"
+#include "privilege.h"
+#include "s_newconf.h"
+
+static void block_services_kill(void *data);
+
+mapi_hfn_list_av1 m_nokillservices_hfnlist[] = {
+	{ "can_kill", (hookfn) block_services_kill },
+	{ NULL, NULL }
+};
+
+static void
+block_services_kill(void *vdata)
+{
+	hook_data_client_approval *data = (hook_data_client_approval *) vdata;
+
+	if (!MyClient(data->client))
+		return;
+
+	if (!data->approved)
+		return;
+
+	if (IsService(data->target))
+	{
+		sendto_one_notice(data->client, ":You may not kill network service %s",
+				data->target->name);
+		data->approved = 0;
+	}
+}
+
+DECLARE_MODULE_AV1(m_nokillservices, NULL, NULL, NULL, NULL,
+			m_nokillservices_hfnlist, "Charybdis 3.4+");
diff --git a/include/hook.h b/include/hook.h
index 08ec5380..88f6cc73 100644
--- a/include/hook.h
+++ b/include/hook.h
@@ -87,6 +87,7 @@ typedef struct
 typedef struct
 {
 	struct Client *client;
+	struct Client *target;
 	int approved;
 } hook_data_client_approval;
 
diff --git a/modules/core/m_kill.c b/modules/core/m_kill.c
index 17042fcc..a058ce82 100644
--- a/modules/core/m_kill.c
+++ b/modules/core/m_kill.c
@@ -40,6 +40,7 @@
 #include "modules.h"
 #include "s_newconf.h"
 
+static int h_can_kill;
 static char buf[BUFSIZE];
 
 static int ms_kill(struct Client *, struct Client *, int, const char **);
@@ -54,7 +55,12 @@ struct Message kill_msgtab = {
 
 mapi_clist_av1 kill_clist[] = { &kill_msgtab, NULL };
 
-DECLARE_MODULE_AV1(kill, NULL, NULL, kill_clist, NULL, NULL, "$Revision: 3408 $");
+mapi_hlist_av1 kill_hlist[] = {
+	{ "can_kill", &h_can_kill },
+	{ NULL, NULL},
+};
+
+DECLARE_MODULE_AV1(kill, NULL, NULL, kill_clist, kill_hlist, NULL, "$Revision: 3408 $");
 
 /*
 ** mo_kill
@@ -68,6 +74,7 @@ mo_kill(struct Client *client_p, struct Client *source_p, int parc, const char *
 	const char *inpath = client_p->name;
 	const char *user;
 	const char *reason;
+	hook_data_client_approval moduledata;
 
 	user = parv[1];
 
@@ -115,6 +122,16 @@ mo_kill(struct Client *client_p, struct Client *source_p, int parc, const char *
 		return 0;
 	}
 
+	/* Last chance to stop the kill */
+	moduledata.client = source_p;
+	moduledata.target = target_p;
+	moduledata.approved = 1;
+	call_hook(h_can_kill, &moduledata);
+
+	if (moduledata.approved == 0)
+		/* Let the calleee send a message */
+		return 0;
+
 	if(MyConnect(target_p))
 		sendto_one(target_p, ":%s!%s@%s KILL %s :%s",
 			   source_p->name, source_p->username, source_p->host,