MINOR: namespaces: don't build namespace.c if disabled

When namespaces are disabled, support is still reported because the file
is built with almost nothing in it but built anyway. Instead of extending
the scope of the numerous ifdefs in this file, better avoid building it
when namespaces are diabled. In this case we define my_socketat() as an
inline function mapping directly to socket(). The struct netns_entry
still needs to be defined because it's used by various other functions
in the code.

Makefile

@@ -871,6 +871,7 @@ endif
 ifneq ($(USE_NS),)
 OPTIONS_CFLAGS += -DCONFIG_HAP_NS
 BUILD_OPTIONS  += $(call ignore_implicit,USE_NS)
+OPTIONS_OBJS  += src/namespace.o
 endif
 
 #### Global link options
@@ -916,7 +917,7 @@ OBJS = src/proto_http.o src/cfgparse.o src/server.o src/stream.o        \
        src/hpack-dec.o src/memory.o src/lb_fwrr.o src/lb_chash.o        \
        src/lb_fas.o src/hathreads.o src/chunk.o src/lb_map.o            \
        src/xxhash.o src/regex.o src/shctx.o src/buffer.o src/action.o   \
-       src/h1.o src/compression.o src/pipe.o src/namespace.o            \
+       src/h1.o src/compression.o src/pipe.o                            \
        src/sha1.o src/hpack-tbl.o src/hpack-enc.o src/uri_auth.o        \
        src/time.o src/proto_udp.o src/arg.o src/signal.o                \
        src/protocol.o src/lru.o src/hdr_idx.o src/hpack-huff.o          \

include/common/namespace.h

@@ -4,9 +4,6 @@
 #include <stdlib.h>
 #include <ebistree.h>
 
-struct netns_entry;
-int my_socketat(const struct netns_entry *ns, int domain, int type, int protocol);
-
 #ifdef CONFIG_HAP_NS
 
 struct netns_entry
@@ -16,10 +13,21 @@ struct netns_entry
 	int fd;
 };
 
+int my_socketat(const struct netns_entry *ns, int domain, int type, int protocol);
 struct netns_entry* netns_store_insert(const char *ns_name);
 const struct netns_entry* netns_store_lookup(const char *ns_name, size_t ns_name_len);
 
 int netns_init(void);
+
+#else /* no namespace support */
+
+struct netns_entry;
+
+static inline int my_socketat(const struct netns_entry *ns, int domain, int type, int protocol)
+{
+	return socket(domain, type, protocol);
+}
+
 #endif /* CONFIG_HAP_NS */
 
 #endif /* _NAMESPACE_H */

src/namespace.c

@@ -17,8 +17,6 @@
 #include <proto/log.h>
 #include <types/global.h>
 
-#ifdef CONFIG_HAP_NS
-
 /* Opens the namespace <ns_name> and returns the FD or -1 in case of error
  * (check errno).
  */
@@ -88,7 +86,6 @@ const struct netns_entry* netns_store_lookup(const char *ns_name, size_t ns_name
 	else
 		return NULL;
 }
-#endif
 
 /* Opens a socket in the namespace described by <ns> with the parameters <domain>,
  * <type> and <protocol> and returns the FD or -1 in case of error (check errno).
@@ -97,19 +94,15 @@ int my_socketat(const struct netns_entry *ns, int domain, int type, int protocol
 {
 	int sock;
 
-#ifdef CONFIG_HAP_NS
 	if (default_namespace >= 0 && ns && setns(ns->fd, CLONE_NEWNET) == -1)
 		return -1;
-#endif
+
 	sock = socket(domain, type, protocol);
 
-#ifdef CONFIG_HAP_NS
 	if (default_namespace >= 0 && ns && setns(default_namespace, CLONE_NEWNET) == -1) {
 		close(sock);
 		return -1;
 	}
-#endif
-
 	return sock;
 }