core bugfix: rsyslog messages may not always have FQDN

Even if hostname FQDN is configured, rsyslog internal messages generated
after rsyslog startup and before the first HUP will not necessarily have
FQDN but instead only the shortname of the local host. This commit
fixes the situation.

Special thanks to github user eciii for doing a great bug analysis
and helping us considerably to fix the issue.

closes #5218

runtime/glbl.c

@@ -7,7 +7,7 @@
  *
  * Module begun 2008-04-16 by Rainer Gerhards
  *
- * Copyright 2008-2022 Rainer Gerhards and Adiscon GmbH.
+ * Copyright 2008-2023 Rainer Gerhards and Adiscon GmbH.
  *
  * This file is part of the rsyslog runtime library.
  *
@@ -1447,7 +1447,7 @@ glblDoneLoadCnf(void)
 	 * hostname. These messages are currently in iminternal queue. Once they
 	 * are taken from that queue, the hostname will be adapted.
 	 */
-	queryLocalHostname();
+	queryLocalHostname(loadConf);
 	RETiRet;
 }
 

runtime/net.c

@@ -1160,7 +1160,7 @@ cvthname(struct sockaddr_storage *f, prop_t **localName, prop_t **fqdn, prop_t *
  */
 #define EMPTY_HOSTNAME_REPLACEMENT "localhost-empty-hostname"
 static rsRetVal
-getLocalHostname(uchar **ppName)
+getLocalHostname(rsconf_t *const pConf, uchar **ppName)
 {
 	DEFiRet;
 	char hnbuf[8192];
@@ -1183,7 +1183,7 @@ getLocalHostname(uchar **ppName)
 
 	char *dot = strstr(hnbuf, ".");
 	struct addrinfo *res = NULL;
-	if(!empty_hostname && dot == NULL && runConf != NULL && !glbl.GetDisableDNS(runConf)) {
+	if(!empty_hostname && dot == NULL && pConf != NULL && !glbl.GetDisableDNS(pConf)) {
 		/* we need to (try) to find the real name via resolver */
 		struct addrinfo flags;
 		memset(&flags, 0, sizeof(flags));

runtime/net.h

@@ -152,7 +152,7 @@ BEGINinterface(net) /* name must also be changed in ENDinterface macro! */
 		int ipfreebind, char *device);
 	void (*closeUDPListenSockets)(int *finet);
 	int (*isAllowedSender)(uchar *pszType, struct sockaddr *pFrom, const char *pszFromHost); /* deprecated! */
-	rsRetVal (*getLocalHostname)(uchar**);
+	rsRetVal (*getLocalHostname)(rsconf_t *const, uchar**);
 	int (*should_use_so_bsdcompat)(void);
 	/* permitted peer handling should be replaced by something better (see comments above) */
 	rsRetVal (*AddPermittedPeer)(permittedPeers_t **ppRootPeer, uchar *pszID);

runtime/rsconf.h

@@ -1,6 +1,6 @@
 /* The rsconf object. It models a complete rsyslog configuration.
  *
- * Copyright 2011-2022 Rainer Gerhards and Adiscon GmbH.
+ * Copyright 2011-2023 Rainer Gerhards and Adiscon GmbH.
  *
  * This file is part of the rsyslog runtime library.
  *

runtime/rsyslog.h

@@ -3,7 +3,7 @@
  *
  * Begun 2005-09-15 RGerhards
  *
- * Copyright (C) 2005-2019 by Rainer Gerhards and Adiscon GmbH
+ * Copyright (C) 2005-2023 by Rainer Gerhards and Adiscon GmbH
  *
  * This file is part of the rsyslog runtime library.
  *
@@ -782,7 +782,7 @@ rsRetVal rsrtExit(void);
 int rsrtIsInit(void);
 void rsrtSetErrLogger(void (*errLogger)(const int, const int, const uchar*));
 void dfltErrLogger(const int, const int, const uchar *errMsg);
-rsRetVal queryLocalHostname(void);
+rsRetVal queryLocalHostname(rsconf_t *const);
 
 
 /* this define below is (later) intended to be used to implement empty

tools/rsyslogd.c

@@ -253,15 +253,18 @@ get_bHadHUP(void)
 	return ret;
 }
 
+/* we need a pointer to the conf, because in early startup stage we
+ * need to use loadConf, later on runConf.
+ */
 rsRetVal
-queryLocalHostname(void)
+queryLocalHostname(rsconf_t *const pConf)
 {
 	uchar *LocalHostName = NULL;
 	uchar *LocalDomain = NULL;
 	uchar *LocalFQDNName;
 	DEFiRet;
 
-	CHKiRet(net.getLocalHostname(&LocalFQDNName));
+	CHKiRet(net.getLocalHostname(pConf, &LocalFQDNName));
 	uchar *dot = (uchar*) strstr((char*)LocalFQDNName, ".");
 	if(dot == NULL) {
 		CHKmalloc(LocalHostName = (uchar*) strdup((char*)LocalFQDNName));
@@ -1956,7 +1959,7 @@ doHUP(void)
 		logmsgInternal(NO_ERRCODE, LOG_SYSLOG|LOG_INFO, (uchar*)buf, 0);
 	}
 
-	queryLocalHostname(); /* re-read our name */
+	queryLocalHostname(runConf); /* re-read our name */
 	ruleset.IterateAllActions(ourConf, doHUPActions, NULL);
 	DBGPRINTF("doHUP: doing modules\n");
 	modDoHUP();