Add ns_goodmail for whitelist NickServ emails

This adds support for whitelisting email domains allowed to register
nicks with NickServ.  It is the opposite of the included badmail module.

README.md

@@ -164,6 +164,12 @@ encrypted and you want to set SOPER passwords.
 
 Generates a random password.
 
+#### ns_goodmail.c
+
+Maintains a whitelist of email domains that are allowed to
+register NickServ nicks.  This allows you to say only
+\*@example.com email address can register nicks.
+
 #### ns_guestnoreg.c
 
 Disallows the registration of nicks beginning with a string

ns_goodmail.c

@@ -0,0 +1,236 @@
+/*
+ * Copyright (c) 2013 Brandon Turner
+ * Rights to this code are as documented in doc/LICENSE.
+ *
+ * Restrict registration to certain email addresses.
+ *
+ */
+
+#include "atheme.h"
+
+DECLARE_MODULE_V1
+(
+	"contrib/ns_goodmail", false, _modinit, _moddeinit,
+	PACKAGE_STRING,
+	"Atheme Development Group <http://www.atheme.net>"
+);
+
+static void check_registration(hook_user_register_check_t *hdata);
+static void ns_cmd_goodmail(sourceinfo_t *si, int parc, char *parv[]);
+
+static void write_bedb(database_handle_t *db);
+static void db_h_be(database_handle_t *db, const char *type);
+
+command_t ns_goodmail = { "GOODMAIL", N_("Restrict registration to certain email addresses."), PRIV_USER_ADMIN, 3, ns_cmd_goodmail, { .path = "contrib/ns_goodmail" } };
+
+struct goodmail_ {
+	char *mail;
+	time_t mail_ts;
+	char *creator;
+	char *reason;
+};
+
+typedef struct goodmail_ goodmail_t;
+
+mowgli_list_t ns_maillist;
+
+void _modinit(module_t *m)
+{
+	if (!module_find_published("backend/opensex"))
+	{
+		slog(LG_INFO, "Module %s requires use of the OpenSEX database backend, refusing to load.", m->name);
+		m->mflags = MODTYPE_FAIL;
+		return;
+	}
+
+	hook_add_event("user_can_register");
+	hook_add_user_can_register(check_registration);
+	hook_add_db_write(write_bedb);
+
+	db_register_type_handler("BE", db_h_be);
+
+	service_named_bind_command("nickserv", &ns_goodmail);
+}
+
+void _moddeinit(module_unload_intent_t intent)
+{
+	hook_del_user_can_register(check_registration);
+	hook_del_db_write(write_bedb);
+
+	db_unregister_type_handler("BE");
+
+	service_named_unbind_command("nickserv", &ns_goodmail);
+}
+
+static void write_bedb(database_handle_t *db)
+{
+	mowgli_node_t *n;
+
+	MOWGLI_ITER_FOREACH(n, ns_maillist.head)
+	{
+		goodmail_t *l = n->data;
+
+		db_start_row(db, "BE");
+		db_write_word(db, l->mail);
+		db_write_time(db, l->mail_ts);
+		db_write_word(db, l->creator);
+		db_write_str(db, l->reason);
+		db_commit_row(db);
+	}
+}
+
+static void db_h_be(database_handle_t *db, const char *type)
+{
+	const char *mail = db_sread_word(db);
+	time_t mail_ts = db_sread_time(db);
+	const char *creator = db_sread_word(db);
+	const char *reason = db_sread_str(db);
+
+	goodmail_t *l = smalloc(sizeof(goodmail_t));
+	l->mail = sstrdup(mail);
+	l->mail_ts = mail_ts;
+	l->creator = sstrdup(creator);
+	l->reason = sstrdup(reason);
+	mowgli_node_add(l, mowgli_node_create(), &ns_maillist);
+}
+static void check_registration(hook_user_register_check_t *hdata)
+{
+	mowgli_node_t *n;
+	goodmail_t *l;
+
+	if (hdata->approved)
+		return;
+
+	MOWGLI_ITER_FOREACH(n, ns_maillist.head)
+	{
+		l = n->data;
+
+		if (!match(l->mail, hdata->email))
+		{
+			return;
+		}
+	}
+
+	command_fail(hdata->si, fault_noprivs, "Sorry, we do not accept registrations with email addresses from that domain.  Use another address.");
+	hdata->approved = 1;
+	slog(LG_INFO, "REGISTER:GOODMAIL: %s to \2%s\2 by \2%s\2",
+			hdata->account, hdata->email,
+			hdata->si->su != NULL ? hdata->si->su->nick : get_source_name(hdata->si));
+}
+
+static void ns_cmd_goodmail(sourceinfo_t *si, int parc, char *parv[])
+{
+	char *action = parv[0];
+	char *email = parv[1];
+	char *reason = parv[2];
+	mowgli_node_t *n, *tn;
+	goodmail_t *l;
+
+	if (!action)
+	{
+		command_fail(si, fault_needmoreparams, STR_INSUFFICIENT_PARAMS, "goodmail");
+		command_fail(si, fault_needmoreparams, _("Syntax: goodmail ADD|DEL|LIST [parameters]"));
+		return;
+	}
+
+	if (!strcasecmp("ADD", action))
+	{
+		if (!email || !reason)
+		{
+			command_fail(si, fault_needmoreparams, STR_INSUFFICIENT_PARAMS, "goodmail");
+			command_fail(si, fault_needmoreparams, _("Syntax: goodmail ADD <email> <reason>"));
+			return;
+		}
+
+		if (si->smu == NULL)
+		{
+			command_fail(si, fault_noprivs, _("You are not logged in."));
+			return;
+		}
+
+		/* search for it */
+		MOWGLI_ITER_FOREACH(n, ns_maillist.head)
+		{
+			l = n->data;
+
+			if (!irccasecmp(l->mail, email))
+			{
+				command_success_nodata(si, _("Email \2%s\2 has already been whitelisted."), email);
+				return;
+			}
+		}
+
+		l = smalloc(sizeof(goodmail_t));
+		l->mail = sstrdup(email);
+		l->mail_ts = CURRTIME;;
+		l->creator = sstrdup(get_source_name(si));
+		l->reason = sstrdup(reason);
+
+		logcommand(si, CMDLOG_ADMIN, "goodmail:ADD: \2%s\2 (Reason: \2%s\2)", email, reason);
+
+		n = mowgli_node_create();
+		mowgli_node_add(l, n, &ns_maillist);
+
+		command_success_nodata(si, _("You have whitelisted email address \2%s\2."), email);
+		return;
+	}
+	else if (!strcasecmp("DEL", action))
+	{
+		if (!email)
+		{
+			command_fail(si, fault_needmoreparams, STR_INSUFFICIENT_PARAMS, "goodmail");
+			command_fail(si, fault_needmoreparams, _("Syntax: goodmail DEL <email>"));
+			return;
+		}
+
+		MOWGLI_ITER_FOREACH_SAFE(n, tn, ns_maillist.head)
+		{
+			l = n->data;
+
+			if (!irccasecmp(l->mail, email))
+			{
+				logcommand(si, CMDLOG_ADMIN, "goodmail:DEL: \2%s\2", l->mail);
+
+				mowgli_node_delete(n, &ns_maillist);
+
+				free(l->mail);
+				free(l->creator);
+				free(l->reason);
+				free(l);
+
+				return;
+			}
+		}
+		command_success_nodata(si, _("Email pattern \2%s\2 not found in goodmail database."), email);
+		return;
+	}
+	else if (!strcasecmp("LIST", action))
+	{
+		char buf[BUFSIZE];
+		struct tm tm;
+
+		MOWGLI_ITER_FOREACH(n, ns_maillist.head)
+		{
+			l = n->data;
+
+			tm = *localtime(&l->mail_ts);
+			strftime(buf, BUFSIZE, TIME_FORMAT, &tm);
+			command_success_nodata(si, "Email: \2%s\2, Reason: \2%s\2 (%s - %s)",
+				l->mail, l->reason, l->creator, buf);
+		}
+		command_success_nodata(si, "End of list.");
+		logcommand(si, CMDLOG_GET, "goodmail:LIST");
+		return;
+	}
+	else
+	{
+		command_fail(si, fault_badparams, STR_INVALID_PARAMS, "goodmail");
+		return;
+	}
+}
+
+/* vim:cinoptions=>s,e0,n0,f0,{0,}0,^0,=s,ps,t0,c3,+s,(2s,us,)20,*30,gs,hs
+ * vim:ts=8
+ * vim:sw=8
+ * vim:noexpandtab
+ */