Make ZRealm.srvrs be an array of pointers

With asynchronous name resolution and timers, we need to keep around
pointers to individual other-realm servers.  This, we cannot move
existing servers around in memory without causing data corruption.
But, realm_init() wants to reallocate the srvrs array for a realm when
adding servers.

Therefore, to allow ZRealm.srvrs to be reallocated without changing the
addresses of existing servers, it is converted from an array of servers
to an array of pointers to servers.

3 files changed, 48 insertions, 39 deletions

diff --git a/server/realm.c b/server/realm.c
index 4f9ce2f..f105887 100644
--- a/server/realm.c
+++ b/server/realm.c
@@ -106,7 +106,8 @@ realm_get_idx_by_addr(ZRealm *realm,
     int b;
 
     /* loop through the realms */
-    for (srvr = realm->srvrs, b = 0; b < realm->count; b++, srvr++) {
+    for (b = 0; b < realm->count; b++) {
+	srvr = realm->srvrs[b];
 	if (!is_usable(srvr))
 	    continue;
 	if (srvr->addr.sin_addr.s_addr == who->sin_addr.s_addr)
@@ -120,13 +121,11 @@ static int
 realm_next_idx_by_idx(ZRealm *realm, int idx)
 {
     ZRealm_server *srvr;
-    int a, b;
+    int b;
 
     /* loop through the servers */
-    srvr = realm->srvrs; a = idx;
-    while (a > 0) { a--; srvr++; }
-
-    for (b = idx; b < realm->count; b++, srvr++) {
+    for (b = idx; b < realm->count; b++) {
+	srvr = realm->srvrs[b];
 	if (!is_usable(srvr))
 	    continue;
 	if (!srvr->dontsend)
@@ -135,7 +134,8 @@ realm_next_idx_by_idx(ZRealm *realm, int idx)
 
     /* recycle */
     if (idx != 0)
-	for (srvr = realm->srvrs, b = 0; b < idx; b++, srvr++) {
+	for (b = 0; b < idx; b++) {
+	    srvr = realm->srvrs[b];
 	    if (!is_usable(srvr))
 		continue;
 	    if (!srvr->dontsend)
@@ -352,9 +352,8 @@ realm_which_realm(struct sockaddr_in *who)
     /* loop through the realms */
     for (a = 0; a < nrealms; a++)
 	/* loop through the addresses for the realm */
-	for (srvr = otherrealms[a]->srvrs, b = 0;
-	     b < otherrealms[a]->count;
-	     b++, srvr++) {
+	for (b = 0; b < otherrealms[a]->count; b++) {
+	    srvr = otherrealms[a]->srvrs[b];
 	    if (!is_usable(srvr))
 		continue;
 	    if (srvr->addr.sin_addr.s_addr == who->sin_addr.s_addr)
@@ -532,7 +531,6 @@ void
 realm_init(void)
 {
     Client *client;
-    ZRealm_server *srvr;
     ZRealmname *rlmnames;
     ZRealm *rlm;
     int ii, jj, kk, nrlmnames;
@@ -570,14 +568,14 @@ realm_init(void)
 	    /* jj: server entry in otherrealms */
 	    /* kk: server entry in rlmnames */
 	    for (jj = 0; jj < rlm->count; jj++) {
-		rlm->srvrs[jj].deleted = 1;
+		rlm->srvrs[jj]->deleted = 1;
 		for (kk = 0; kk < rlmnames[ii].nused; kk++) {
-		    if (rlmnames[ii].servers[kk].name != rlm->srvrs[jj].name)
+		    if (rlmnames[ii].servers[kk].name != rlm->srvrs[jj]->name)
 			continue;
 		    /* update existing server */
-		    rlm->srvrs[jj].dontsend = rlmnames[ii].servers[kk].dontsend;
-		    rlm->srvrs[jj].deleted = 0;
-		    rlm_lookup_server_address(&rlm->srvrs[jj]);
+		    rlm->srvrs[jj]->dontsend = rlmnames[ii].servers[kk].dontsend;
+		    rlm->srvrs[jj]->deleted = 0;
+		    rlm_lookup_server_address(rlm->srvrs[jj]);
 
 		    /* mark realm.list server entry used */
 		    rlmnames[ii].servers[kk].deleted = 1;
@@ -588,15 +586,20 @@ realm_init(void)
 		if (!rlmnames[ii].servers[kk].deleted) jj++;
 
 	    rlm->srvrs = realloc(rlm->srvrs,
-				 (rlm->count + jj) * sizeof(ZRealm_server));
+				 (rlm->count + jj) * sizeof(ZRealm_server *));
 	    if (!rlm->srvrs) {
 		syslog(LOG_CRIT, "realloc failed in realm_init");
 		abort();
 	    }
 	    for (kk = 0; kk < rlmnames[ii].nused; kk++) {
 		if (rlmnames[ii].servers[kk].deleted) continue;
-		rlm->srvrs[rlm->count] = rlmnames[ii].servers[kk];
-		rlm_lookup_server_address(&rlm->srvrs[rlm->count]);
+		rlm->srvrs[rlm->count] = malloc(sizeof(ZRealm_server));
+		if (!rlm->srvrs[rlm->count]) {
+		    syslog(LOG_CRIT, "realloc failed in realm_init");
+		    abort();
+		}
+		*(rlm->srvrs[rlm->count]) = rlmnames[ii].servers[kk];
+		rlm_lookup_server_address(rlm->srvrs[rlm->count]);
 		rlm->count++;
 	    }
 	    /* The current server might have been deleted or marked dontsend.
@@ -632,9 +635,15 @@ realm_init(void)
 
 	/* convert names to addresses */
 	rlm->count = rlmnames[ii].nused;
-	rlm->srvrs = rlmnames[ii].servers;
-	for (srvr = rlm->srvrs, jj = 0; jj < rlm->count; jj++, srvr++)
-	    rlm_lookup_server_address(srvr);
+	rlm->srvrs = malloc(rlm->count * sizeof(ZRealm_server *));
+	if (!rlm->srvrs) {
+	    syslog(LOG_CRIT, "malloc failed in realm_init");
+	    abort();
+	}
+	for (jj = 0; jj < rlm->count; jj++) {
+	    rlm->srvrs[jj] = &rlmnames[ii].servers[jj];
+	    rlm_lookup_server_address(rlm->srvrs[jj]);
+	}
 
 	client = (Client *) malloc(sizeof(Client));
 	if (!client) {
@@ -946,9 +955,9 @@ realm_new_server(struct sockaddr_in *sin,
 	    realm->idx = realm_next_idx_by_idx(realm, (realm->idx + 1) %
 					       realm->count);
 	}
-	zdbug((LOG_DEBUG, "rlm_new_srv: switched servers (%s)", inet_ntoa((realm->srvrs[realm->idx].addr).sin_addr)));
+	zdbug((LOG_DEBUG, "rlm_new_srv: switched servers (%s)", inet_ntoa((realm->srvrs[realm->idx]->addr).sin_addr)));
     } else {
-      zdbug((LOG_DEBUG, "rlm_new_srv: not switching servers (%s)", inet_ntoa((realm->srvrs[realm->idx].addr).sin_addr)));
+      zdbug((LOG_DEBUG, "rlm_new_srv: not switching servers (%s)", inet_ntoa((realm->srvrs[realm->idx]->addr).sin_addr)));
     }
     return 0;
 }
@@ -967,12 +976,12 @@ realm_set_server(struct sockaddr_in *sin,
     idx = realm_get_idx_by_addr(realm, sin);
 
     /* Not exactly */
-    if (realm->srvrs[idx].dontsend != 0)
+    if (!is_usable(realm->srvrs[idx]) || realm->srvrs[idx]->dontsend != 0)
 	return ZSRV_NORLM;
 
     realm->idx = idx;
 
-    zdbug((LOG_DEBUG, "rlm_pick_srv: switched servers (%s)", inet_ntoa((realm->srvrs[realm->idx].addr).sin_addr)));
+    zdbug((LOG_DEBUG, "rlm_pick_srv: switched servers (%s)", inet_ntoa((realm->srvrs[realm->idx]->addr).sin_addr)));
 
     return 0;
 }
@@ -1035,7 +1044,7 @@ realm_sendit(ZNotice_t *notice,
     }
 
     /* now send */
-    if ((retval = ZSetDestAddr(&realm->srvrs[realm->idx].addr)) != ZERR_NONE) {
+    if ((retval = ZSetDestAddr(&realm->srvrs[realm->idx]->addr)) != ZERR_NONE) {
 	syslog(LOG_WARNING, "rlm_sendit set addr: %s",
 	       error_message(retval));
 	free(pack);
@@ -1128,14 +1137,14 @@ rlm_rexmit(void *arg)
 					   realm->count);
 	zdbug((LOG_DEBUG, "rlm_rexmit: %s switching servers:%d (%s)",
 	       realm->name, realm->idx,
-	       inet_ntoa((realm->srvrs[realm->idx].addr).sin_addr)));
+	       inet_ntoa((realm->srvrs[realm->idx]->addr).sin_addr)));
     }
 
     /* throttle back if it looks like the realm is down */
     if ((realm->state != REALM_DEAD) ||
 	((nackpacket->rexmits % (realm->count+1)) == 1)) {
 	/* do the retransmit */
-	retval = ZSetDestAddr(&realm->srvrs[realm->idx].addr);
+	retval = ZSetDestAddr(&realm->srvrs[realm->idx]->addr);
 	if (retval != ZERR_NONE) {
 	    syslog(LOG_WARNING, "rlm_rexmit set addr: %s",
 		   error_message(retval));
@@ -1148,10 +1157,10 @@ rlm_rexmit(void *arg)
 	/* no per-server nack queues for foreign realms yet, doesn't matter */
 	nackpacket->dest.rlm.rlm_srv_idx = realm->idx;
 	zdbug((LOG_DEBUG, "rlm_rexmit(%s): send to %s", realm->name,
-	       inet_ntoa((realm->srvrs[realm->idx].addr).sin_addr)));
+	       inet_ntoa((realm->srvrs[realm->idx]->addr).sin_addr)));
     } else {
 	zdbug((LOG_DEBUG, "rlm_rexmit(%s): not sending to %s", realm->name,
-	       inet_ntoa((realm->srvrs[realm->idx].addr).sin_addr)));
+	       inet_ntoa((realm->srvrs[realm->idx]->addr).sin_addr)));
     }
 
     /* reset the timer */
@@ -1161,7 +1170,7 @@ rlm_rexmit(void *arg)
 		      rlm_rexmit, nackpacket);
     if (rexmit_times[nackpacket->rexmits%NUM_REXMIT_TIMES] == -1) {
 	zdbug((LOG_DEBUG, "rlm_rexmit(%s): would send at -1 to %s",
-	       realm->name, inet_ntoa((realm->srvrs[realm->idx].addr).sin_addr)));
+	       realm->name, inet_ntoa((realm->srvrs[realm->idx]->addr).sin_addr)));
     }
 
     return;
@@ -1176,10 +1185,10 @@ realm_dump_realms(FILE *fp)
 	(void) fprintf(fp, "%d:%s\n", ii, otherrealms[ii]->name);
 	for (jj = 0; jj < otherrealms[ii]->count; jj++) {
 	    (void) fprintf(fp, "\t%s%s%s%s\n",
-			   inet_ntoa(otherrealms[ii]->srvrs[jj].addr.sin_addr),
-			   otherrealms[ii]->srvrs[jj].dontsend ? " nosend" : "",
-			   otherrealms[ii]->srvrs[jj].got_addr ? " gotaddr" : "",
-			   otherrealms[ii]->srvrs[jj].deleted ? " deleted" : "");
+			   inet_ntoa(otherrealms[ii]->srvrs[jj]->addr.sin_addr),
+			   otherrealms[ii]->srvrs[jj]->dontsend ? " nosend" : "",
+			   otherrealms[ii]->srvrs[jj]->got_addr ? " gotaddr" : "",
+			   otherrealms[ii]->srvrs[jj]->deleted ? " deleted" : "");
 	}
 	/* dump the subs */
 	subscr_dump_subs(fp, otherrealms[ii]->subs);
@@ -1254,7 +1263,7 @@ realm_sendit_auth(ZNotice_t *notice,
 	       error_message(retval));
 
     if (!retval) {
-	retval = ZSetDestAddr(&realm->srvrs[realm->idx].addr);
+	retval = ZSetDestAddr(&realm->srvrs[realm->idx]->addr);
 	if (retval)
 	    syslog(LOG_WARNING, "rlm_sendit_auth: ZSetDestAddr: %s",
 		   error_message(retval));
diff --git a/server/server.c b/server/server.c
index 2983cf6..934c700 100644
--- a/server/server.c
+++ b/server/server.c
@@ -763,7 +763,7 @@ send_stats(struct sockaddr_in *who)
     for (i = 0; i < nrealms ; i++) {
       realm = otherrealms[i];
       sprintf(buf, "%s(%s)/%s", realm->name,
-	      inet_ntoa((realm->srvrs[realm->idx].addr).sin_addr),
+	      inet_ntoa((realm->srvrs[realm->idx]->addr).sin_addr),
 	      rlm_states[(int) realm->state]);
       responses[num_resp++] = strsave(buf);
     }
diff --git a/server/zserver.h b/server/zserver.h
index 822a90c..734e4ed 100644
--- a/server/zserver.h
+++ b/server/zserver.h
@@ -126,7 +126,7 @@ struct _ZRealm {
     String *namestr;			/* realm's name */
     char *name;				/* always namestr->string */
     int count;
-    ZRealm_server *srvrs;
+    ZRealm_server **srvrs;
     int idx;				/* which server we are connected to */
     Destlist *subs;                     /* what their clients sub to */
     Destlist *remsubs;                  /* our subs on their end */