build: fix optional dependency handling

Author: Pavel Šimerda

Diff for: Makefile.am

@@ -35,7 +35,6 @@ include_HEADERS = \
 lib_LTLIBRARIES = \
 	libnetresolve.la \
 	libnetresolve-libc.la \
-	libnetresolve-asyncns.la \
 	libnss_netresolve.la
 
 libnetresolve_la_SOURCES = \
@@ -55,7 +54,7 @@ libnetresolve_la_SOURCES = \
 	lib/epoll.c \
 	lib/select.c
 libnetresolve_la_LDFLAGS = \
-	$(AM_LDFLAGS) -lldns \
+	$(AM_LDFLAGS) $(LDNS_LIBS) \
 	-export-symbols-regex '^netresolve_'
 
 libnetresolve_libc_la_SOURCES = \
@@ -67,13 +66,17 @@ libnetresolve_libc_la_LDFLAGS = \
 libnetresolve_libc_la_LIBADD = \
 	libnetresolve.la
 
+if BUILD_FRONTEND_ASYNCNS
+lib_LTLIBRARIES += libnetresolve-asyncns.la
+
 libnetresolve_asyncns_la_SOURCES = \
 	compat/asyncns.c
 libnetresolve_asyncns_la_LDFLAGS = \
 	$(AM_LDFLAGS) \
 	--export-all-symbols
 libnetresolve_asyncns_la_LIBADD = \
 	libnetresolve.la
+endif
 
 libnss_netresolve_la_SOURCES = \
 	compat/nsswitch.c
@@ -87,10 +90,12 @@ lib_LTLIBRARIES += \
 	libnetresolve-backend-hosts.la \
 	libnetresolve-backend-hostname.la \
 	libnetresolve-backend-libc.la \
-	libnetresolve-backend-asyncns.la \
 	libnetresolve-backend-nss.la \
 	libnetresolve-backend-exec.la
 
+if BUILD_BACKEND_ASYNCNS
+lib_LTLIBRARIES += libnetresolve-backend-asyncns.la
+endif
 if BUILD_BACKEND_ARESDNS
 lib_LTLIBRARIES += libnetresolve-backend-aresdns.la
 endif
@@ -109,8 +114,6 @@ libnetresolve_backend_hosts_la_SOURCES = backends/hosts.c
 libnetresolve_backend_hostname_la_SOURCES = backends/hostname.c
 libnetresolve_backend_libc_la_SOURCES = backends/libc.c
 libnetresolve_backend_libc_la_LDFLAGS = $(AM_LDFLAGS) -lresolv
-libnetresolve_backend_asyncns_la_SOURCES = backends/asyncns.c
-libnetresolve_backend_asyncns_la_LDFLAGS = -lasyncns
 libnetresolve_backend_nss_la_SOURCES = backends/nss.c
 libnetresolve_backend_exec_la_SOURCES = backends/exec.c
 
@@ -121,21 +124,25 @@ libnetresolve_backend_aresdns_la_CPPFLAGS = $(AM_CPPFLAGS) $(ARES_CFLAGS) -DUSE_
 endif
 if BUILD_BACKEND_UBDNS
 libnetresolve_backend_ubdns_la_SOURCES = backends/dns.c
-libnetresolve_backend_ubdns_la_LDFLAGS = $(AM_LDFLAGS) -lunbound
+libnetresolve_backend_ubdns_la_LDFLAGS = $(AM_LDFLAGS) $(UNBOUND_LIBS)
 libnetresolve_backend_ubdns_la_CPPFLAGS = $(AM_CPPFLAGS) -DUSE_UNBOUND=1
 endif
 if BUILD_BACKEND_AVAHI
 libnetresolve_backend_avahi_la_SOURCES = backends/avahi.c
 libnetresolve_backend_avahi_la_LDFLAGS = $(AM_LDFLAGS) $(AVAHI_LIBS)
 libnetresolve_backend_avahi_la_CPPFLAGS = $(AM_CPPFLAGS)
 endif
+if BUILD_BACKEND_ASYNCNS
+libnetresolve_backend_asyncns_la_SOURCES = backends/asyncns.c
+libnetresolve_backend_asyncns_la_LDFLAGS = $(ASYNCNS_LIBS)
+endif
 
 bin_PROGRAMS = netresolve getaddrinfo getnameinfo gethostbyname gethostbyaddr res_query
 bin_SCRIPTS = tools/wrapresolve
 
 netresolve_SOURCES = tools/netresolve.c
 netresolve_LDADD = libnetresolve.la
-netresolve_LDFLAGS = $(AM_LDFLAGS) -lldns
+netresolve_LDFLAGS = $(AM_LDFLAGS) $(LDNS_LIBS)
 
 getaddrinfo_SOURCES = tools/getaddrinfo.c tools/compat.c
 
@@ -146,7 +153,7 @@ gethostbyname_SOURCES = tools/gethostbyname.c tools/compat.c
 gethostbyaddr_SOURCES = tools/gethostbyaddr.c tools/compat.c
 
 res_query_SOURCES = tools/res_query.c tools/compat.c
-res_query_LDFLAGS = $(AM_LDFLAGS) -lresolv -lldns
+res_query_LDFLAGS = $(AM_LDFLAGS) $(LDNS_LIBS) -lresolv
 
 TESTS = \
 	tests/test-netresolve.sh \
@@ -188,9 +195,12 @@ noinst_PROGRAMS = \
 	test-gethostbyname \
 	test-gethostbyname2 \
 	test-gethostbyname_r \
-	test-gethostbyname2_r \
+	test-gethostbyname2_r
+if BUILD_FRONTEND_ASYNCNS
+noinst_PROGRAMS += \
 	test-asyncns \
 	test-asyncns-cancel
+endif
 if BUILD_ALL_TESTS
 TESTS += \
 	test-libevent \

Diff for: configure.ac

@@ -24,37 +24,47 @@ if test "$use_ldns" != no; then
 	AC_CHECK_LIB([ldns], [ldns_wire2pkt], [use_ldns=yes], [use_ldns=no])
 	if test "$with_ldns" = yes -a "$with_ldns" = no; then AC_MSG_ERROR([Bulding with ldns requested but not available.]); fi
 fi
-AS_IF([test "$use_ldns"], AC_DEFINE(USE_LDNS, 1, [Use ldns library for DNS data operations (Default: yes).]))
+AS_IF([test "$use_ldns" = yes], AC_DEFINE(USE_LDNS, 1, [Use ldns library for DNS data operations (Default: yes).]))
+AS_IF([test "$use_ldns" = yes], AC_SUBST(LDNS_LIBS, -lldns))
 
 AC_ARG_WITH(c-ares, AS_HELP_STRING([--with-c-ares|--without-c-ares], [Build c-ares backend (Default: yes)]), [build_aresdns="$with_c_ares"])
 if test "$build_aresdns" != no; then
 	PKG_CHECK_MODULES([ARES], [libcares], [build_aresdns=yes], [build_aresdns=no])
 	if test "$use_ldns" = no; then build_aresdns=no; fi
 	if test "$with_c_ares" = yes -a "$build_aresdns" = no; then AC_MSG_ERROR([Support for c-ares requested but not available.]); fi
 fi
-AM_CONDITIONAL(BUILD_BACKEND_ARESDNS, [test $build_aresdns = "yes"])
+AM_CONDITIONAL(BUILD_BACKEND_ARESDNS, [test $build_aresdns = yes])
 
 AC_ARG_WITH(unbound, AS_HELP_STRING([--with-unbound|--without-unbound], [Build libunbound backend (Default: yes)]), [build_ubdns="$with_unbound"])
 if test "$build_ubdns" != no; then
 	AC_CHECK_LIB([unbound], [ub_ctx_create], [build_ubdns=yes], [build_ubdns=no])
 	if test "$use_ldns" = no; then build_ubdns=no; fi
 	if test "$with_unbound" = yes -a "$build_ubdns" = no; then AC_MSG_ERROR([Support for libunbound requested but not available.]); fi
 fi
-AM_CONDITIONAL(BUILD_BACKEND_UBDNS, [test $build_ubdns = "yes"])
+AM_CONDITIONAL(BUILD_BACKEND_UBDNS, [test "$build_ubdns" = yes])
+AS_IF([test "$build_ubdns" = yes], AC_SUBST(UNBOUND_LIBS, -lunbound))
 
 AC_ARG_WITH(avahi, AS_HELP_STRING([--with-avahi|--without-avahi], [Build libavahi backend (Default: yes)]), [build_avahi="$with_avahi"])
 if test "$build_avahi" != no; then
 	PKG_CHECK_MODULES([AVAHI], [avahi-client], [build_avahi=yes], [build_avahi=no])
 	if test "$with_avahi" = yes -a "$build_avahi" = no; then AC_MSG_ERROR([Support for libavahi requested but not available.]); fi
 fi
-AM_CONDITIONAL(BUILD_BACKEND_AVAHI, [test $build_avahi = "yes"])
+AM_CONDITIONAL(BUILD_BACKEND_AVAHI, [test $build_avahi = yes])
+
+AC_ARG_WITH(asyncns, AS_HELP_STRING([--with-asyncns|--without-asyncns], [Build libasyncns based backend (Default: yes)]), [build_asyncns="$with_asyncns"])
+if test "$build_asyncns" != no; then
+	PKG_CHECK_MODULES([ASYNCNS], [libasyncns], [build_asyncns=yes], [build_asyncns=no])
+	if test "$with_asyncns" = yes -a "$build_asyncns" = no; then AC_MSG_ERROR([Support for libasyncns requested but not available.]); fi
+fi
+AM_CONDITIONAL(BUILD_FRONTEND_ASYNCNS, [test $build_asyncns = yes])
+AM_CONDITIONAL(BUILD_BACKEND_ASYNCNS, [test $build_asyncns = yes])
 
 AC_ARG_ENABLE(tests, AS_HELP_STRING([--enable-tests|--disable-tests], [Build tests using additional dependencies (Default: no)]))
-AS_IF([test "$enable_tests" = "yes"],
+AS_IF([test "$enable_tests" = yes],
 	PKG_CHECK_MODULES([GLIB], [glib-2.0])
 	AC_CHECK_LIB([event], [event_base_new], [EVENT_LIBS=-levent])
 	AC_SUBST(EVENT_LIBS))
-AM_CONDITIONAL(BUILD_ALL_TESTS, [test "$enable_tests" = "yes"])
+AM_CONDITIONAL(BUILD_ALL_TESTS, [test "$enable_tests" = yes])
 
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_FILES([
@@ -78,11 +88,16 @@ Compiler:
  * cflags: ${CFLAGS}
  * ldflags: ${LDFLAGS}
 
+Optional frontends:
+
+ * asyncns: $build_asyncns
+
 Optional backends:
 
  * aresdns: $build_aresdns
  * ubdns: $build_ubdns
  * avahi: $build_avahi
+ * asyncns: $build_asyncns
 
 Other dependencies:
 

Diff for: include/netresolve-private.h

@@ -38,6 +38,7 @@
 #include <net/if.h>
 #include <arpa/inet.h>
 #include <sys/socket.h>
+#include <unistd.h>
 #include <assert.h>
 
 #define debug_context(context, format, ...) debug( \

Diff for: tools/netresolve.c

@@ -23,11 +23,14 @@
  */
 #include <netresolve-private.h>
 #include <getopt.h>
-#include <ldns/ldns.h>
 #include <arpa/nameser.h>
 #include <netinet/ip_icmp.h>
 #include <linux/icmpv6.h>
 
+#ifdef USE_LDNS
+#include <ldns/ldns.h>
+#endif
+
 static int
 count_argv(char **argv)
 {
@@ -79,6 +82,7 @@ on_connect(netresolve_query_t context, int idx, int sock, void *user_data)
 static char *
 get_dns_string(netresolve_query_t query)
 {
+#ifdef USE_LDNS
 	const uint8_t *answer;
 	size_t length;
 
@@ -98,6 +102,9 @@ get_dns_string(netresolve_query_t query)
 
 	ldns_pkt_free(pkt);
 	return result;
+#else
+	return NULL;
+#endif
 }
 
 static const char *
@@ -288,10 +295,18 @@ main(int argc, char **argv)
 			port_str = optarg;
 			break;
 		case 'C':
+#ifdef USE_LDNS
 			cls = ldns_get_rr_class_by_name(optarg);
+#else
+			cls = strtoll(optarg, NULL, 10);
+#endif
 			break;
 		case 'T':
+#ifdef USE_LDNS
 			type = ldns_get_rr_type_by_name(optarg);
+#else
+			type = strtoll(optarg, NULL, 10);
+#endif
 			break;
 		default:
 			exit(EXIT_FAILURE);

Diff for: tools/res_query.c

@@ -28,7 +28,10 @@
 #include <netdb.h>
 #include <arpa/nameser.h>
 #include <resolv.h>
+
+#ifdef USE_LDNS
 #include <ldns/ldns.h>
+#endif
 
 #include "compat.h"
 
@@ -54,7 +57,6 @@ main(int argc, char **argv)
 	int type = ns_t_a;
 	uint8_t answer[SIZE];
 	int length = 0;
-	ldns_pkt *pkt;
 
 	while ((opt = getopt_long(argc, argv, opts, longopts, &idx)) != -1) {
 		switch (opt) {
@@ -104,11 +106,15 @@ main(int argc, char **argv)
 	printf("result:\n");
 	printf("  length = %d\n", length);
 
+#ifdef USE_LDNS
+	ldns_pkt *pkt;
+
 	if (length > 0 && !ldns_wire2pkt(&pkt, answer, length)) {
 		printf("  answer:\n%s\n", ldns_pkt2str(pkt));
 
 		ldns_pkt_free(pkt);
 	}
+#endif
 
 	exit(EXIT_SUCCESS);
 }