From: Vladimír Čunát <vladimir.cunat@nic.cz>
Date: Thu, 10 Oct 2019 13:16:03 +0000 (+0200)
Subject: modules/watchdog: use abort() for restarts
X-Git-Tag: v4.3.0~14^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cc7ad97055c48b66929bc4c3c6372314faf8d72c;p=thirdparty%2Fknot-resolver.git

modules/watchdog: use abort() for restarts

Motivation: core-dump might be very useful, and in this case there
are even very useful pointers on the C stack.
---

diff --git a/modules/watchdog/README.rst b/modules/watchdog/README.rst
index 04341e59c..cd2fbd038 100644
--- a/modules/watchdog/README.rst
+++ b/modules/watchdog/README.rst
@@ -17,8 +17,8 @@ answers correctly. To use this feature you must configure DNS name and type to q
 
 Each single query from watchdog must result in answer with
 RCODE = NOERROR or NXDOMAIN. Any other result will terminate the resolver
-(with exit code 69) to allow the supervisor process to do cleanup and restart
-the resolver.
+(with SIGABRT) to allow the supervisor process to do cleanup, gather coredump
+and restart the resolver.
 
 It is recommended to use a name with a very short TTL to make sure the watchdog
 is testing all parts of resolver and not only its cache. Obviously this check
diff --git a/modules/watchdog/watchdog.lua b/modules/watchdog/watchdog.lua
index 2251a4141..7a7f5aa54 100644
--- a/modules/watchdog/watchdog.lua
+++ b/modules/watchdog/watchdog.lua
@@ -3,6 +3,7 @@ local ffi = require('ffi')
 ffi.cdef([[
 	int sd_watchdog_enabled(int unset_environment, uint64_t *usec);
 	int sd_notify(int unset_environment, const char *state);
+	void abort(void);
 ]])
 
 local watchdog = {}
@@ -13,8 +14,8 @@ local function sd_signal_ok()
 end
 
 function private.fail_callback()
-	log('[watchdog] TERMINATING resolver, supervisor is expected to restart it')
-	os.exit(69)  -- unclean exit code = EX_UNAVAILABLE
+	log('[watchdog] ABORTING resolver, supervisor is expected to restart it')
+	ffi.C.abort()
 end
 
 -- logging
diff --git a/systemd/kresd@.service.in b/systemd/kresd@.service.in
index 3e30a33ed..6454cc2d1 100644
--- a/systemd/kresd@.service.in
+++ b/systemd/kresd@.service.in
@@ -14,7 +14,6 @@ ExecStart=@sbin_dir@/kresd --config=@etc_dir@/kresd.conf
 User=@user@
 TimeoutStopSec=10s
 WatchdogSec=10s
-RestartForceExitStatus=69
 Restart=on-abnormal
 LimitNOFILE=1048576
 Sockets=kresd.socket