MEDIUM: server: split srv_init() in srv_preinit() + srv_postinit()

We actually need more granularity to split srv postparsing init tasks:
Some of them are required to be run BEFORE the config is checked, and
some of them AFTER the config is checked.

Thus we push the logic from 368d0136 ("MEDIUM: server: add and use
srv_init() function") a little bit further and split the function
in two distinct ones, one of them executed under check_config_validity()
and the other one using REGISTER_POST_SERVER_CHECK() hook.

SRV_F_CHECKED flag was removed because it is no longer needed,
srv_preinit() is only called once, and so is srv_postinit().

include/haproxy/server-t.h

@@ -171,7 +171,7 @@ enum srv_init_state {
 #define SRV_F_DEFSRV_USE_SSL 0x4000      /* default-server uses SSL */
 #define SRV_F_DELETED 0x8000             /* srv is deleted but not yet purged */
 #define SRV_F_STRICT_MAXCONN 0x10000     /* maxconn is to be strictly enforced, as a limit of outbound connections */
-#define SRV_F_CHECKED      0x20000       /* set once server was postparsed */
+/* unused: 0x20000 */
 
 /* configured server options for send-proxy (server->pp_opts) */
 #define SRV_PP_V1               0x0001   /* proxy protocol version 1 */

include/haproxy/server.h

@@ -74,7 +74,7 @@ struct server *new_server(struct proxy *proxy);
 void srv_take(struct server *srv);
 struct server *srv_drop(struct server *srv);
 void srv_free_params(struct server *srv);
-int srv_init(struct server *srv);
+int srv_preinit(struct server *srv);
 void srv_set_ssl(struct server *s, int use_ssl);
 const char *srv_adm_st_chg_cause(enum srv_adm_st_chg_cause cause);
 const char *srv_op_st_chg_cause(enum srv_op_st_chg_cause cause);

src/cfgparse.c

@@ -2824,7 +2824,7 @@ int check_config_validity()
 	 * as some of the fields may be accessed soon
 	 */
 	MT_LIST_FOR_EACH_ENTRY_LOCKED(newsrv, &servers_list, global_list, back) {
-		err_code |= srv_init(newsrv);
+		err_code |= srv_preinit(newsrv);
 		if (err_code & ERR_CODE)
 			goto out;
 	}

src/server.c

@@ -3363,7 +3363,7 @@ static int _srv_parse_tmpl_init(struct server *srv, struct proxy *px)
  * This function is expected to be called after _srv_parse_init() initialization
  * but only when the effective server's proxy mode is known, which is not always
  * the case during parsing time, in which case the function will be called during
- * postparsing thanks to the srv_init() below.
+ * postparsing thanks to the srv_postinit() below.
  *
  * Returns ERR_NONE on success else a combination or ERR_CODE.
  */
@@ -3427,7 +3427,27 @@ static int _srv_check_proxy_mode(struct server *srv, char postparse)
 
 	return err_code;
 }
-/* Finish initializing the server after parsing
+
+/* Finish initializing the server after parsing and before config checks
+ *
+ * Returns ERR_NONE on success else a combination or ERR_CODE.
+ */
+static int srv_init_per_thr(struct server *srv);
+int srv_preinit(struct server *srv)
+{
+	int err_code = ERR_NONE;
+
+	if (srv_init_per_thr(srv) == -1) {
+		ha_alert("error during per-thread init for %s/%s server\n", srv->proxy->id, srv->id);
+		err_code |= ERR_ALERT | ERR_FATAL;
+		goto out;
+	}
+
+ out:
+	return err_code;
+}
+
+/* Finish initializing the server after parsing and config checks
  *
  * We must be careful that checks / postinits performed within this function
  * don't depend or conflict with other postcheck functions that are registered
@@ -3437,14 +3457,10 @@ static int _srv_check_proxy_mode(struct server *srv, char postparse)
  */
 static int init_srv_requeue(struct server *srv);
 static int init_srv_slowstart(struct server *srv);
-static int srv_init_per_thr(struct server *srv);
+int srv_postinit(struct server *srv)
-int srv_init(struct server *srv)
 {
 	int err_code = ERR_NONE;
 
-	if (srv->flags & SRV_F_CHECKED)
-		return ERR_NONE; // nothing to do
-
 	err_code |= _srv_check_proxy_mode(srv, 1);
 
 	if (err_code & ERR_CODE)
@@ -3474,12 +3490,6 @@ int srv_init(struct server *srv)
 	if (err_code & ERR_CODE)
 		goto out;
 
-	if (srv_init_per_thr(srv) == -1) {
-		ha_alert("error during per-thread init for %s/%s server\n", srv->proxy->id, srv->id);
-		err_code |= ERR_ALERT | ERR_FATAL;
-		goto out;
-	}
-
 	/* initialize idle conns lists */
 	if (srv->max_idle_conns != 0) {
 		srv->curr_idle_thr = ha_aligned_zalloc(64, global.nbthread * sizeof(*srv->curr_idle_thr));
@@ -3492,11 +3502,9 @@ int srv_init(struct server *srv)
 	}
 
  out:
-	if (!(err_code & ERR_CODE))
-		srv->flags |= SRV_F_CHECKED;
 	return err_code;
 }
-REGISTER_POST_SERVER_CHECK(srv_init);
+REGISTER_POST_SERVER_CHECK(srv_postinit);
 
 /* Allocate a new server pointed by <srv> and try to parse the first arguments
  * in <args> as an address for a server or an address-range for a template or
@@ -6181,7 +6189,10 @@ static int cli_parse_add_server(char **args, char *payload, struct appctx *appct
 		srv->agent.state &= ~CHK_ST_ENABLED;
 	}
 
-	errcode = srv_init(srv);
+	errcode = srv_preinit(srv);
+	if (errcode)
+		goto out;
+	errcode = srv_postinit(srv);
 	if (errcode)
 		goto out;