ctld: Only check physical port linking in a single configuration context

Commit 969876fcee moved struct pport from being per-configuration to
being a "global" object shared across multiple configurations.  As a
result, the check for duplicate ports actually spanned across
configurations, such that reloading a configuration would now think
that existing physical ports were already linked.

The linking field in pport added in the C++-ification (commit
6acc7afa34) faithfully replicated this bug (albeit simpler as I had
noticed that the TAILQ links weren't used after the earlier commit).

To restore the desired behavior, remove the linking field from struct
pport entirely and use a local unordered_map in conf::add_pports which
tracks if a given pport is claimed by more than one target.

PR:		293076
Reported by:	Ken J. Thomson <thomsonk@yandex.com>
Fixes:		969876fcee ("ctld: parse config file independently of getting kernel info")
Sponsored by:	Chelsio Communications
Differential Revision:	https://reviews.freebsd.org/D57093

usr.sbin/ctld/ctld.cc

@@ -1175,7 +1175,6 @@ conf::add_port(struct target *target, struct pport *pp)
 		return (false);
 	}
 
-	pp->link();
 	return (true);
 }
 
@@ -2641,6 +2640,7 @@ conf_new_from_file(const char *path, bool ucl)
 bool
 conf::add_pports(struct kports &kports)
 {
+	std::unordered_map<struct pport *, struct target *> linked_ports;
 	struct pport *pp;
 	int ret, i_pp, i_vp;
 
@@ -2654,11 +2654,13 @@ conf::add_pports(struct kports &kports)
 			 */
 			pp = kports.find_port(pport);
 			if (pp != nullptr) {
-				if (pp->linked()) {
+				const auto &pair = linked_ports.try_emplace(pp,
+				    targ);
+				if (!pair.second) {
 					log_warnx("can't link port \"%s\" to "
-					    "%s, port already linked to some "
-					    "target", pport.c_str(),
-					    targ->label());
+					    "%s, port already linked to %s",
+					    pport.c_str(), targ->label(),
+					    pair.first->second->label());
 					return (false);
 				}
 

usr.sbin/ctld/ctld.hh

@@ -567,13 +567,9 @@ struct pport {
 	const char *name() const { return pp_name.c_str(); }
 	uint32_t ctl_port() const { return pp_ctl_port; }
 
-	bool linked() const { return pp_linked; }
-	void link() { pp_linked = true; }
-
 private:
 	std::string			pp_name;
 	uint32_t			pp_ctl_port;
-	bool				pp_linked = false;
 };
 
 struct kports {