* add proper error codes and patch everything to make use of it

* parameter validity checkin in all user visible functions of libavahi-core
* two new python tools/examples avahi-resolve-host-name and avahi-resolve-address


git-svn-id: file:///home/lennart/svn/public/avahi/trunk@238 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe

14 files changed, 329 insertions, 46 deletions

diff --git a/avahi-core/avahi-reflector.c b/avahi-core/avahi-reflector.c
index 7af0dd4..0a91b87 100644
--- a/avahi-core/avahi-reflector.c
+++ b/avahi-core/avahi-reflector.c
@@ -34,6 +34,7 @@ int main(int argc, char*argv[]) {
     AvahiServer *server;
     AvahiServerConfig config;
     GMainLoop *loop;
+    gint error;
 
     avahi_server_config_init(&config);
     config.publish_hinfo = FALSE;
@@ -43,7 +44,7 @@ int main(int argc, char*argv[]) {
     config.use_ipv6 = FALSE;
     config.enable_reflector = TRUE;
     
-    server = avahi_server_new(NULL, &config, NULL, NULL);
+    server = avahi_server_new(NULL, &config, NULL, NULL, &error);
     avahi_server_config_free(&config);
 
     loop = g_main_loop_new(NULL, FALSE);
diff --git a/avahi-core/avahi-test.c b/avahi-core/avahi-test.c
index cc950d4..5db2473 100644
--- a/avahi-core/avahi-test.c
+++ b/avahi-core/avahi-test.c
@@ -217,10 +217,11 @@ int main(int argc, char *argv[]) {
     AvahiServiceBrowser *sb;
     AvahiServiceResolver *sr;
     AvahiDNSServerBrowser *dsb;
+    gint error;
     
     avahi_server_config_init(&config);
 /*     config.host_name = g_strdup("test"); */
-    server = avahi_server_new(NULL, &config, server_callback, NULL);
+    server = avahi_server_new(NULL, &config, server_callback, NULL, &error);
     avahi_server_config_free(&config);
 
     k = avahi_key_new("_http._tcp.local", AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_PTR);
diff --git a/avahi-core/browse-dns-server.c b/avahi-core/browse-dns-server.c
index f8e8f30..057f3e3 100644
--- a/avahi-core/browse-dns-server.c
+++ b/avahi-core/browse-dns-server.c
@@ -157,15 +157,21 @@ AvahiDNSServerBrowser *avahi_dns_server_browser_new(AvahiServer *server, AvahiIf
     g_assert(callback);
     g_assert(type == AVAHI_DNS_SERVER_RESOLVE || type == AVAHI_DNS_SERVER_UPDATE);
 
+    if (domain && !avahi_valid_domain_name(domain)) {
+        avahi_server_set_errno(server, AVAHI_ERR_INVALID_DOMAIN_NAME);
+        return NULL;
+    }
+    
     b = g_new(AvahiDNSServerBrowser, 1);
     b->server = server;
-    b->domain_name = avahi_normalize_name(domain ? domain : "local.");
+    b->domain_name = avahi_normalize_name(domain ? domain : "local");
     b->callback = callback;
     b->userdata = userdata;
     b->aprotocol = aprotocol;
     b->n_info = 0;
 
     AVAHI_LLIST_HEAD_INIT(AvahiDNSServerInfo, b->info);
+    AVAHI_LLIST_PREPEND(AvahiDNSServerBrowser, browser, server->dns_server_browsers, b);
     
     n = g_strdup_printf("%s.%s",type == AVAHI_DNS_SERVER_RESOLVE ? "_domain._udp" : "_dns-update._udp", b->domain_name);
     k = avahi_key_new(n, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_SRV);
@@ -174,7 +180,10 @@ AvahiDNSServerBrowser *avahi_dns_server_browser_new(AvahiServer *server, AvahiIf
     b->record_browser = avahi_record_browser_new(server, interface, protocol, k, record_browser_callback, b);
     avahi_key_unref(k);
 
-    AVAHI_LLIST_PREPEND(AvahiDNSServerBrowser, browser, server->dns_server_browsers, b);
+    if (!b->record_browser) {
+        avahi_dns_server_browser_free(b);
+        return NULL;
+    }
     
     return b;
 }
@@ -187,7 +196,8 @@ void avahi_dns_server_browser_free(AvahiDNSServerBrowser *b) {
     
     AVAHI_LLIST_REMOVE(AvahiDNSServerBrowser, browser, b->server->dns_server_browsers, b);
 
-    avahi_record_browser_free(b->record_browser);
+    if (b->record_browser)
+        avahi_record_browser_free(b->record_browser);
     g_free(b->domain_name);
     g_free(b);
 }
diff --git a/avahi-core/browse-domain.c b/avahi-core/browse-domain.c
index c6331b4..de3cb1b 100644
--- a/avahi-core/browse-domain.c
+++ b/avahi-core/browse-domain.c
@@ -60,6 +60,12 @@ AvahiDomainBrowser *avahi_domain_browser_new(AvahiServer *server, AvahiIfIndex i
     
     g_assert(server);
     g_assert(callback);
+    g_assert(type >= AVAHI_DOMAIN_BROWSER_BROWSE && type <= AVAHI_DOMAIN_BROWSER_BROWSE_LEGACY);
+
+    if (domain && !avahi_valid_domain_name(domain)) {
+        avahi_server_set_errno(server, AVAHI_ERR_INVALID_DOMAIN_NAME);
+        return NULL;
+    }
 
     b = g_new(AvahiDomainBrowser, 1);
     b->server = server;
@@ -67,6 +73,8 @@ AvahiDomainBrowser *avahi_domain_browser_new(AvahiServer *server, AvahiIfIndex i
     b->callback = callback;
     b->userdata = userdata;
 
+    AVAHI_LLIST_PREPEND(AvahiDomainBrowser, browser, server->domain_browsers, b);
+
     switch (type) {
         case AVAHI_DOMAIN_BROWSER_BROWSE:
             n = g_strdup_printf("b._dns-sd._udp.%s", b->domain_name);
@@ -97,7 +105,10 @@ AvahiDomainBrowser *avahi_domain_browser_new(AvahiServer *server, AvahiIfIndex i
     b->record_browser = avahi_record_browser_new(server, interface, protocol, k, record_browser_callback, b);
     avahi_key_unref(k);
 
-    AVAHI_LLIST_PREPEND(AvahiDomainBrowser, browser, server->domain_browsers, b);
+    if (!b->record_browser) {
+        avahi_domain_browser_free(b);
+        return NULL;
+    }
     
     return b;
 }
@@ -107,7 +118,9 @@ void avahi_domain_browser_free(AvahiDomainBrowser *b) {
 
     AVAHI_LLIST_REMOVE(AvahiDomainBrowser, browser, b->server->domain_browsers, b);
 
-    avahi_record_browser_free(b->record_browser);
+    if (b->record_browser)
+        avahi_record_browser_free(b->record_browser);
+    
     g_free(b->domain_name);
     g_free(b);
 }
diff --git a/avahi-core/browse-service-type.c b/avahi-core/browse-service-type.c
index 7cd6cf7..3534b6f 100644
--- a/avahi-core/browse-service-type.c
+++ b/avahi-core/browse-service-type.c
@@ -90,12 +90,18 @@ AvahiServiceTypeBrowser *avahi_service_type_browser_new(AvahiServer *server, gin
     g_assert(server);
     g_assert(callback);
 
+    if (domain && !avahi_valid_domain_name(domain)) {
+        avahi_server_set_errno(server, AVAHI_ERR_INVALID_DOMAIN_NAME);
+        return NULL;
+    }
+
     b = g_new(AvahiServiceTypeBrowser, 1);
     b->server = server;
     b->domain_name = avahi_normalize_name(domain ? domain : "local");
     b->callback = callback;
     b->userdata = userdata;
 
+    AVAHI_LLIST_PREPEND(AvahiServiceTypeBrowser, browser, server->service_type_browsers, b);
 
     n = g_strdup_printf("_services._dns-sd._udp.%s", b->domain_name);
     k = avahi_key_new(n, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_PTR);
@@ -104,7 +110,8 @@ AvahiServiceTypeBrowser *avahi_service_type_browser_new(AvahiServer *server, gin
     b->record_browser = avahi_record_browser_new(server, interface, protocol, k, record_browser_callback, b);
     avahi_key_unref(k);
 
-    AVAHI_LLIST_PREPEND(AvahiServiceTypeBrowser, browser, server->service_type_browsers, b);
+    if (!b->record_browser)
+        return NULL;
     
     return b;
 }
@@ -114,7 +121,9 @@ void avahi_service_type_browser_free(AvahiServiceTypeBrowser *b) {
 
     AVAHI_LLIST_REMOVE(AvahiServiceTypeBrowser, browser, b->server->service_type_browsers, b);
 
-    avahi_record_browser_free(b->record_browser);
+    if (b->record_browser)
+        avahi_record_browser_free(b->record_browser);
+    
     g_free(b->domain_name);
     g_free(b);
 }
diff --git a/avahi-core/browse-service.c b/avahi-core/browse-service.c
index f72ce6c..34a2536 100644
--- a/avahi-core/browse-service.c
+++ b/avahi-core/browse-service.c
@@ -93,21 +93,36 @@ AvahiServiceBrowser *avahi_service_browser_new(AvahiServer *server, AvahiIfIndex
     g_assert(callback);
     g_assert(service_type);
 
+    if (!avahi_valid_service_type(service_type)) {
+        avahi_server_set_errno(server, AVAHI_ERR_INVALID_SERVICE_TYPE);
+        return NULL;
+    }
+
+    if (domain && !avahi_valid_domain_name(domain)) {
+        avahi_server_set_errno(server, AVAHI_ERR_INVALID_DOMAIN_NAME);
+        return NULL;
+    }
+
     b = g_new(AvahiServiceBrowser, 1);
     b->server = server;
     b->domain_name = avahi_normalize_name(domain ? domain : "local");
     b->service_type = avahi_normalize_name(service_type);
     b->callback = callback;
     b->userdata = userdata;
+    AVAHI_LLIST_PREPEND(AvahiServiceBrowser, browser, server->service_browsers, b);
 
     n = g_strdup_printf("%s.%s", b->service_type, b->domain_name);
     k = avahi_key_new(n, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_PTR);
     g_free(n);
     
     b->record_browser = avahi_record_browser_new(server, interface, protocol, k, record_browser_callback, b);
+
     avahi_key_unref(k);
 
-    AVAHI_LLIST_PREPEND(AvahiServiceBrowser, browser, server->service_browsers, b);
+    if (!b->record_browser) {
+        avahi_service_browser_free(b);
+        return NULL;
+    }
     
     return b;
 }
@@ -117,7 +132,9 @@ void avahi_service_browser_free(AvahiServiceBrowser *b) {
 
     AVAHI_LLIST_REMOVE(AvahiServiceBrowser, browser, b->server->service_browsers, b);
 
-    avahi_record_browser_free(b->record_browser);
+    if (b->record_browser)
+        avahi_record_browser_free(b->record_browser);
+    
     g_free(b->domain_name);
     g_free(b->service_type);
     g_free(b);
diff --git a/avahi-core/browse.c b/avahi-core/browse.c
index 5f4d216..5885cb4 100644
--- a/avahi-core/browse.c
+++ b/avahi-core/browse.c
@@ -124,7 +124,15 @@ AvahiRecordBrowser *avahi_record_browser_new(AvahiServer *server, AvahiIfIndex i
     g_assert(key);
     g_assert(callback);
 
-    g_assert(!avahi_key_is_pattern(key));
+    if (avahi_key_is_pattern(key)) {
+        avahi_server_set_errno(server, AVAHI_ERR_IS_PATTERN);
+        return NULL;
+    }
+
+    if (!avahi_key_valid(key)) {
+        avahi_server_set_errno(server, AVAHI_ERR_INVALID_KEY);
+        return NULL;
+    }
     
     b = g_new(AvahiRecordBrowser, 1);
     b->dead = FALSE;
diff --git a/avahi-core/conformance-test.c b/avahi-core/conformance-test.c
index ccc9a12..13704c3 100644
--- a/avahi-core/conformance-test.c
+++ b/avahi-core/conformance-test.c
@@ -101,8 +101,9 @@ static void server_callback(AvahiServer *s, AvahiServerState state, gpointer use
 
 int main(int argc, char *argv[]) {
     GMainLoop *loop = NULL;
+    gint error;
 
-    avahi = avahi_server_new(NULL, NULL, server_callback, NULL);
+    avahi = avahi_server_new(NULL, NULL, server_callback, NULL, &error);
     
     loop = g_main_loop_new(NULL, FALSE);
     g_timeout_add(1000*5, dump_timeout, avahi);
diff --git a/avahi-core/core.h b/avahi-core/core.h
index 25e9c0a..1adf244 100644
--- a/avahi-core/core.h
+++ b/avahi-core/core.h
@@ -35,7 +35,9 @@
 
 #include <avahi-common/cdecl.h>
 
+#ifndef DOXYGEN_SHOULD_SKIP_THIS
 AVAHI_C_DECL_BEGIN
+#endif
 
 /** An mDNS responder object */
 typedef struct AvahiServer AvahiServer;
@@ -46,19 +48,42 @@ typedef struct AvahiEntry AvahiEntry;
 /** A group of locally registered DNS RRs */
 typedef struct AvahiEntryGroup AvahiEntryGroup;
 
+#ifndef DOXYGEN_SHOULD_SKIP_THIS
 AVAHI_C_DECL_END
+#endif
 
 #include <avahi-common/address.h>
 #include <avahi-common/rr.h>
 #include <avahi-common/alternative.h>
 
+#ifndef DOXYGEN_SHOULD_SKIP_THIS
 AVAHI_C_DECL_BEGIN
+#endif
 
 /** Error codes used by avahi */
 enum { 
-    AVAHI_OK = 0,                      /**< OK */
-    AVAHI_ERR_FAILURE = -1,            /**< Generic error code */
-    AVAHI_ERR_BAD_STATE = -2           /**< Object was in a bad state */
+    AVAHI_OK = 0,                          /**< OK */
+    AVAHI_ERR_FAILURE = -1,                /**< Generic error code */
+    AVAHI_ERR_BAD_STATE = -2,              /**< Object was in a bad state */
+    AVAHI_ERR_INVALID_HOST_NAME = -3,      /**< Invalid host name */
+    AVAHI_ERR_INVALID_DOMAIN_NAME = -4,    /**< Invalid domain name */
+    AVAHI_ERR_NO_NETWORK = -5,             /**< No suitable network protocol available */
+    AVAHI_ERR_INVALID_TTL = -6,            /**< Invalid DNS TTL */
+    AVAHI_ERR_IS_PATTERN = -7,             /**< RR key is pattern */
+    AVAHI_ERR_LOCAL_COLLISION = -8,        /**< Local name collision */
+    AVAHI_ERR_INVALID_RECORD = -9,         /**< Invalid RR */
+    AVAHI_ERR_INVALID_SERVICE_NAME = -10,  /**< Invalid service name */
+    AVAHI_ERR_INVALID_SERVICE_TYPE = -11,  /**< Invalid service type */
+    AVAHI_ERR_INVALID_PORT = -12,          /**< Invalid port number */
+    AVAHI_ERR_INVALID_KEY = -13,           /**< Invalid key */
+    AVAHI_ERR_INVALID_ADDRESS = -14,       /**< Invalid address */
+    AVAHI_ERR_TIMEOUT = -15,               /**< Timeout reached */
+    AVAHI_ERR_TOO_MANY_CLIENTS = -16,      /**< Too many clients */
+    AVAHI_ERR_TOO_MANY_OBJECTS = -17,      /**< Too many objects */
+    AVAHI_ERR_TOO_MANY_ENTRIES = -18,      /**< Too many entries */
+    AVAHI_ERR_OS = -19,                    /**< OS error */
+    AVAHI_ERR_ACCESS_DENIED = -20,         /**< Access denied */
+    AVAHI_ERR_MAX = -21
 };
 
 /** States of a server object */
@@ -113,7 +138,8 @@ AvahiServer *avahi_server_new(
     GMainContext *c,               /**< The GLIB main loop context to attach to */
     const AvahiServerConfig *sc,   /**< If non-NULL a pointer to a configuration structure for the server. The server makes an internal deep copy of this structure, so you may free it using avahi_server_config_done() immediately after calling this function. */
     AvahiServerCallback callback,  /**< A callback which is called whenever the state of the server changes */
-    gpointer userdata              /**< An opaque pointer which is passed to the callback function */);
+    gpointer userdata,             /**< An opaque pointer which is passed to the callback function */
+    gint *error);
 
 /** Free an mDNS responder object */
 void avahi_server_free(AvahiServer* s);
@@ -603,6 +629,14 @@ AvahiDNSServerBrowser *avahi_dns_server_browser_new(
 /** Free an AvahiDNSServerBrowser object */
 void avahi_dns_server_browser_free(AvahiDNSServerBrowser *b);
 
+/** Return a human readable error string for the specified error code */
+const gchar *avahi_strerror(gint error);
+
+/** Return the last error code */
+gint avahi_server_errno(AvahiServer *s);
+
+#ifndef DOXYGEN_SHOULD_SKIP_THIS
 AVAHI_C_DECL_END
+#endif
 
 #endif
diff --git a/avahi-core/resolve-address.c b/avahi-core/resolve-address.c
index d315ac9..89f9bcf 100644
--- a/avahi-core/resolve-address.c
+++ b/avahi-core/resolve-address.c
@@ -111,6 +111,11 @@ AvahiAddressResolver *avahi_address_resolver_new(AvahiServer *server, AvahiIfInd
     
     r->record_browser = avahi_record_browser_new(server, interface, protocol, k, record_browser_callback, r);
     avahi_key_unref(k);
+
+    if (!r->record_browser) {
+        avahi_address_resolver_free(r);
+        return NULL;
+    }
     
     return r;
 }
diff --git a/avahi-core/resolve-host-name.c b/avahi-core/resolve-host-name.c
index 0ab2e73..c18722d 100644
--- a/avahi-core/resolve-host-name.c
+++ b/avahi-core/resolve-host-name.c
@@ -115,6 +115,11 @@ AvahiHostNameResolver *avahi_host_name_resolver_new(AvahiServer *server, AvahiIf
 
     g_assert(aprotocol == AVAHI_PROTO_UNSPEC || aprotocol == AVAHI_PROTO_INET || aprotocol == AVAHI_PROTO_INET6);
 
+    if (!avahi_valid_domain_name(host_name)) {
+        avahi_server_set_errno(server, AVAHI_ERR_INVALID_HOST_NAME);
+        return NULL;
+    }
+    
     r = g_new(AvahiHostNameResolver, 1);
     r->server = server;
     r->host_name = avahi_normalize_name(host_name);
@@ -127,20 +132,34 @@ AvahiHostNameResolver *avahi_host_name_resolver_new(AvahiServer *server, AvahiIf
     r->time_event = avahi_time_event_queue_add(server->time_event_queue, &tv, time_event_callback, r);
 
     AVAHI_LLIST_PREPEND(AvahiHostNameResolver, resolver, server->host_name_resolvers, r);
+
+    r->record_browser_aaaa = r->record_browser_a = NULL;
     
     if (aprotocol == AVAHI_PROTO_INET || aprotocol == AVAHI_PROTO_UNSPEC) {
         k = avahi_key_new(host_name, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_A);
         r->record_browser_a = avahi_record_browser_new(server, interface, protocol, k, record_browser_callback, r);
         avahi_key_unref(k);
+
+        if (!r->record_browser_a)
+            goto fail;
     } 
 
     if (aprotocol == AVAHI_PROTO_INET6 || aprotocol == AVAHI_PROTO_UNSPEC) {
         k = avahi_key_new(host_name, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_AAAA);
         r->record_browser_aaaa = avahi_record_browser_new(server, interface, protocol, k, record_browser_callback, r);
         avahi_key_unref(k);
+
+        if (!r->record_browser_aaaa)
+            goto fail;
     }
-    
+
+    g_assert(r->record_browser_aaaa || r->record_browser_a);
+
     return r;
+
+fail:
+    avahi_host_name_resolver_free(r);
+    return NULL;
 }
 
 void avahi_host_name_resolver_free(AvahiHostNameResolver *r) {
diff --git a/avahi-core/resolve-service.c b/avahi-core/resolve-service.c
index b15af4f..2ad38f8 100644
--- a/avahi-core/resolve-service.c
+++ b/avahi-core/resolve-service.c
@@ -206,6 +206,21 @@ AvahiServiceResolver *avahi_service_resolver_new(AvahiServer *server, AvahiIfInd
 
     g_assert(aprotocol == AVAHI_PROTO_UNSPEC || aprotocol == AVAHI_PROTO_INET || aprotocol == AVAHI_PROTO_INET6);
 
+    if (!avahi_valid_service_name(name)) {
+        avahi_server_set_errno(server, AVAHI_ERR_INVALID_SERVICE_NAME);
+        return NULL;
+    }
+
+    if (!avahi_valid_service_type(type)) {
+        avahi_server_set_errno(server, AVAHI_ERR_INVALID_SERVICE_TYPE);
+        return NULL;
+    }
+
+    if (!avahi_valid_domain_name(domain)) {
+        avahi_server_set_errno(server, AVAHI_ERR_INVALID_DOMAIN_NAME);
+        return NULL;
+    }
+    
     r = g_new(AvahiServiceResolver, 1);
     r->server = server;
     r->service_name = g_strdup(name);
@@ -234,10 +249,20 @@ AvahiServiceResolver *avahi_service_resolver_new(AvahiServer *server, AvahiIfInd
     r->record_browser_srv = avahi_record_browser_new(server, interface, protocol, k, record_browser_callback, r);
     avahi_key_unref(k);
 
+    if (!r->record_browser_srv) {
+        avahi_service_resolver_free(r);
+        return NULL;
+    }
+    
     k = avahi_key_new(t, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_TXT);
     r->record_browser_txt = avahi_record_browser_new(server, interface, protocol, k, record_browser_callback, r);
     avahi_key_unref(k);
-    
+
+    if (!r->record_browser_txt) {
+        avahi_service_resolver_free(r);
+        return NULL;
+    }
+
     return r;
 }
 
diff --git a/avahi-core/server.c b/avahi-core/server.c
index 3c38507..c4acf35 100644
--- a/avahi-core/server.c
+++ b/avahi-core/server.c
@@ -259,6 +259,7 @@ static void incoming_probe(AvahiServer *s, AvahiRecord *record, AvahiInterface *
         }
     }
 
+
     if (!ours) {
 
         if (won)
@@ -1221,6 +1222,9 @@ gint avahi_server_set_host_name(AvahiServer *s, const gchar *host_name) {
     g_assert(s);
     g_assert(host_name);
 
+    if (host_name && !avahi_valid_host_name(host_name))
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_HOST_NAME);
+
     withdraw_host_rrs(s);
 
     g_free(s->host_name);
@@ -1236,6 +1240,9 @@ gint avahi_server_set_domain_name(AvahiServer *s, const gchar *domain_name) {
     g_assert(s);
     g_assert(domain_name);
 
+    if (domain_name && !avahi_valid_domain_name(domain_name))
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_DOMAIN_NAME);
+
     withdraw_host_rrs(s);
 
     g_free(s->domain_name);
@@ -1257,8 +1264,20 @@ static void prepare_pollfd(AvahiServer *s, GPollFD *pollfd, gint fd) {
     g_source_add_poll(s->source, pollfd);
 }
 
-AvahiServer *avahi_server_new(GMainContext *c, const AvahiServerConfig *sc, AvahiServerCallback callback, gpointer userdata) {
+static gint valid_server_config(const AvahiServerConfig *sc) {
+
+    if (sc->host_name && !avahi_valid_host_name(sc->host_name))
+        return AVAHI_ERR_INVALID_HOST_NAME;
+    
+    if (sc->domain_name && !avahi_valid_domain_name(sc->domain_name))
+        return AVAHI_ERR_INVALID_DOMAIN_NAME;
+
+    return AVAHI_OK;
+}
+
+AvahiServer *avahi_server_new(GMainContext *c, const AvahiServerConfig *sc, AvahiServerCallback callback, gpointer userdata, gint *error) {
     AvahiServer *s;
+    gint e;
     
     static GSourceFuncs source_funcs = {
         prepare_func,
@@ -1269,6 +1288,12 @@ AvahiServer *avahi_server_new(GMainContext *c, const AvahiServerConfig *sc, Avah
         NULL
     };
 
+    if ((e = valid_server_config(sc)) < 0) {
+        if (error)
+            *error = e;
+        return NULL;
+    }
+    
     s = g_new(AvahiServer, 1);
     s->n_host_rr_pending = 0;
     s->need_entry_cleanup = s->need_group_cleanup = s->need_browser_cleanup = FALSE;
@@ -1282,9 +1307,12 @@ AvahiServer *avahi_server_new(GMainContext *c, const AvahiServerConfig *sc, Avah
     s->fd_ipv6 = s->config.use_ipv6 ? avahi_open_socket_ipv6() : -1;
     
     if (s->fd_ipv6 < 0 && s->fd_ipv4 < 0) {
-        g_critical("Selected neither IPv6 nor IPv4 support, aborting.\n");
         avahi_server_config_free(&s->config);
         g_free(s);
+
+        if (error)
+            *error = AVAHI_ERR_NO_NETWORK;
+        
         return NULL;
     }
 
@@ -1354,6 +1382,8 @@ AvahiServer *avahi_server_new(GMainContext *c, const AvahiServerConfig *sc, Avah
     s->hinfo_entry_group = NULL;
     s->browse_domain_entry_group = NULL;
     register_stuff(s);
+
+    s->error = AVAHI_OK;
     
     return s;
 }
@@ -1461,13 +1491,16 @@ gint avahi_server_add(
     g_assert(r);
 
     if (r->ttl == 0)
-        return -1;
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_TTL);
 
     if (avahi_key_is_pattern(r->key))
-        return -1;
+        return avahi_server_set_errno(s, AVAHI_ERR_IS_PATTERN);
+
+    if (!avahi_record_valid(r))
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_RECORD);
 
     if (check_record_conflict(s, interface, protocol, r, flags) < 0)
-        return -1;
+        return avahi_server_set_errno(s, AVAHI_ERR_LOCAL_COLLISION);
 
     e = g_new(AvahiEntry, 1);
     e->server = s;
@@ -1551,6 +1584,7 @@ gint avahi_server_add_ptr(
     AvahiRecord *r;
     gint ret;
 
+    g_assert(s);
     g_assert(dest);
 
     r = avahi_record_new_full(name ? name : s->host_name_fqdn, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_PTR, ttl);
@@ -1570,11 +1604,16 @@ gint avahi_server_add_address(
     AvahiAddress *a) {
 
     gchar *n = NULL;
-    gint ret = 0;
+    gint ret = AVAHI_OK;
     g_assert(s);
     g_assert(a);
 
     name = name ? (n = avahi_normalize_name(name)) : s->host_name_fqdn;
+
+    if (!avahi_valid_domain_name(name)) {
+        avahi_server_set_errno(s, AVAHI_ERR_INVALID_HOST_NAME);
+        goto fail;
+    }
     
     if (a->family == AVAHI_PROTO_INET) {
         gchar *reverse;
@@ -1584,11 +1623,14 @@ gint avahi_server_add_address(
         r->data.a.address = a->data.ipv4;
         ret = avahi_server_add(s, g, interface, protocol, flags | AVAHI_ENTRY_UNIQUE | AVAHI_ENTRY_ALLOWMUTIPLE, r);
         avahi_record_unref(r);
+
+        if (ret < 0)
+            goto fail;
         
         reverse = avahi_reverse_lookup_name_ipv4(&a->data.ipv4);
-        ret |= avahi_server_add_ptr(s, g, interface, protocol, flags | AVAHI_ENTRY_UNIQUE, AVAHI_DEFAULT_TTL_HOST_NAME, reverse, name);
+        ret = avahi_server_add_ptr(s, g, interface, protocol, flags | AVAHI_ENTRY_UNIQUE, AVAHI_DEFAULT_TTL_HOST_NAME, reverse, name);
         g_free(reverse);
-        
+
     } else {
         gchar *reverse;
         AvahiRecord *r;
@@ -1598,14 +1640,22 @@ gint avahi_server_add_address(
         ret = avahi_server_add(s, g, interface, protocol, flags | AVAHI_ENTRY_UNIQUE | AVAHI_ENTRY_ALLOWMUTIPLE, r);
         avahi_record_unref(r);
 
+        if (ret < 0)
+            goto fail;
+
         reverse = avahi_reverse_lookup_name_ipv6_arpa(&a->data.ipv6);
-        ret |= avahi_server_add_ptr(s, g, interface, protocol, flags | AVAHI_ENTRY_UNIQUE, AVAHI_DEFAULT_TTL_HOST_NAME, reverse, name);
+        ret = avahi_server_add_ptr(s, g, interface, protocol, flags | AVAHI_ENTRY_UNIQUE, AVAHI_DEFAULT_TTL_HOST_NAME, reverse, name);
         g_free(reverse);
+
+        if (ret < 0)
+            goto fail;
     
         reverse = avahi_reverse_lookup_name_ipv6_int(&a->data.ipv6);
-        ret |= avahi_server_add_ptr(s, g, interface, protocol, flags | AVAHI_ENTRY_UNIQUE, AVAHI_DEFAULT_TTL_HOST_NAME, reverse, name);
+        ret = avahi_server_add_ptr(s, g, interface, protocol, flags | AVAHI_ENTRY_UNIQUE, AVAHI_DEFAULT_TTL_HOST_NAME, reverse, name);
         g_free(reverse);
     }
+
+fail:
     
     g_free(n);
 
@@ -1645,6 +1695,8 @@ gint avahi_server_add_txt_strlst(
     const gchar *name,
     AvahiStringList *strlst) {
 
+    g_assert(s);
+
     return server_add_txt_strlst_nocopy(s, g, interface, protocol, flags, ttl, name, avahi_string_list_copy(strlst));
 }
 
@@ -1721,19 +1773,31 @@ static gint server_add_service_strlst_nocopy(
 
     gchar ptr_name[256], svc_name[256], ename[64], enum_ptr[256];
     gchar *t, *d;
-    AvahiRecord *r;
+    AvahiRecord *r = NULL;
     gint ret = 0;
     
     g_assert(s);
     g_assert(type);
     g_assert(name);
 
+    if (!avahi_valid_service_name(name))
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_SERVICE_NAME);
+
+    if (!avahi_valid_service_type(type))
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_SERVICE_TYPE);
+
+    if (domain && !avahi_valid_domain_name(domain))
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_DOMAIN_NAME);
+
+    if (host && !avahi_valid_domain_name(host))
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_HOST_NAME);
+
+    if (port == 0)
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_PORT);
+    
     escape_service_name(ename, sizeof(ename), name);
 
-    if (domain) {
-        while (domain[0] == '.')
-            domain++;
-    } else
+    if (!domain)
         domain = s->domain_name;
 
     if (!host)
@@ -1745,23 +1809,35 @@ static gint server_add_service_strlst_nocopy(
     g_snprintf(ptr_name, sizeof(ptr_name), "%s.%s", t, d);
     g_snprintf(svc_name, sizeof(svc_name), "%s.%s.%s", ename, t, d);
 
-    ret = avahi_server_add_ptr(s, g, interface, protocol, AVAHI_ENTRY_NULL, AVAHI_DEFAULT_TTL, ptr_name, svc_name);
+    if ((ret = avahi_server_add_ptr(s, g, interface, protocol, AVAHI_ENTRY_NULL, AVAHI_DEFAULT_TTL, ptr_name, svc_name)) < 0)
+        goto fail;
 
     r = avahi_record_new_full(svc_name, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_SRV, AVAHI_DEFAULT_TTL_HOST_NAME);
     r->data.srv.priority = 0;
     r->data.srv.weight = 0;
     r->data.srv.port = port;
     r->data.srv.name = avahi_normalize_name(host);
-    ret |= avahi_server_add(s, g, interface, protocol, AVAHI_ENTRY_UNIQUE, r);
+    ret = avahi_server_add(s, g, interface, protocol, AVAHI_ENTRY_UNIQUE, r);
     avahi_record_unref(r);
 
-    ret |= server_add_txt_strlst_nocopy(s, g, interface, protocol, AVAHI_ENTRY_UNIQUE, AVAHI_DEFAULT_TTL, svc_name, strlst);
+    if (ret < 0)
+        goto fail;
+
+    ret = server_add_txt_strlst_nocopy(s, g, interface, protocol, AVAHI_ENTRY_UNIQUE, AVAHI_DEFAULT_TTL, svc_name, strlst);
+    strlst = NULL;
+
+    if (ret < 0)
+        goto fail;
 
     g_snprintf(enum_ptr, sizeof(enum_ptr), "_services._dns-sd._udp.%s", d);
-    ret |=avahi_server_add_ptr(s, g, interface, protocol, AVAHI_ENTRY_NULL, AVAHI_DEFAULT_TTL, enum_ptr, ptr_name);
+    ret = avahi_server_add_ptr(s, g, interface, protocol, AVAHI_ENTRY_NULL, AVAHI_DEFAULT_TTL, enum_ptr, ptr_name);
 
+fail:
+    
     g_free(d);
     g_free(t);
+
+    avahi_string_list_free(strlst);
     
     return ret;
 }
@@ -1778,6 +1854,10 @@ gint avahi_server_add_service_strlst(
     guint16 port,
     AvahiStringList *strlst) {
 
+    g_assert(s);
+    g_assert(type);
+    g_assert(name);
+
     return server_add_service_strlst_nocopy(s, g, interface, protocol, name, type, domain, host, port, avahi_string_list_copy(strlst));
 }
 
@@ -1866,6 +1946,12 @@ gint avahi_server_add_dns_server_address(
     g_assert(type == AVAHI_DNS_SERVER_UPDATE || type == AVAHI_DNS_SERVER_RESOLVE);
     g_assert(address->family == AVAHI_PROTO_INET || address->family == AVAHI_PROTO_INET6);
 
+    if (domain && !avahi_valid_domain_name(domain))
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_DOMAIN_NAME);
+
+    if (port == 0)
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_PORT);
+    
     if (address->family == AVAHI_PROTO_INET) {
         hexstring(n+3, sizeof(n)-3, &address->data, 4);
         r = avahi_record_new_full(n, AVAHI_DNS_CLASS_IN, AVAHI_DNS_TYPE_A, AVAHI_DEFAULT_TTL_HOST_NAME);
@@ -1878,10 +1964,11 @@ gint avahi_server_add_dns_server_address(
     
     ret = avahi_server_add(s, g, interface, protocol, AVAHI_ENTRY_UNIQUE | AVAHI_ENTRY_ALLOWMUTIPLE, r);
     avahi_record_unref(r);
-    
-    ret |= avahi_server_add_dns_server_name(s, g, interface, protocol, domain, type, n, port);
 
-    return ret;
+    if (ret < 0)
+        return ret;
+    
+    return avahi_server_add_dns_server_name(s, g, interface, protocol, domain, type, n, port);
 }
 
 gint avahi_server_add_dns_server_name(
@@ -1902,10 +1989,13 @@ gint avahi_server_add_dns_server_name(
     g_assert(name);
     g_assert(type == AVAHI_DNS_SERVER_UPDATE || type == AVAHI_DNS_SERVER_RESOLVE);
 
-    if (domain) {
-        while (domain[0] == '.')
-            domain++;
-    } else
+    if (domain && !avahi_valid_domain_name(domain))
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_DOMAIN_NAME);
+
+    if (port == 0)
+        return avahi_server_set_errno(s, AVAHI_ERR_INVALID_PORT);
+    
+    if (!domain)
         domain = s->domain_name;
 
     d = avahi_normalize_name(domain);
@@ -1946,6 +2036,8 @@ void avahi_entry_group_change_state(AvahiEntryGroup *g, AvahiEntryGroupState sta
     if (g->state == state)
         return;
 
+    g_assert(state >= AVAHI_ENTRY_GROUP_UNCOMMITED && state <= AVAHI_ENTRY_GROUP_COLLISION);
+
     g->state = state;
     
     if (g->callback)
@@ -2031,7 +2123,7 @@ gint avahi_entry_group_commit(AvahiEntryGroup *g) {
     g_assert(!g->dead);
 
     if (g->state != AVAHI_ENTRY_GROUP_UNCOMMITED && g->state != AVAHI_ENTRY_GROUP_COLLISION)
-        return AVAHI_ERR_BAD_STATE;
+        return avahi_server_set_errno(g->server, AVAHI_ERR_BAD_STATE);
 
     g->n_register_try++;
 
@@ -2201,3 +2293,47 @@ AvahiServerConfig* avahi_server_config_copy(AvahiServerConfig *ret, const AvahiS
 
     return ret;
 }
+
+const gchar *avahi_strerror(gint error) {
+    g_assert(-error >= 0 && -error < -AVAHI_ERR_MAX);
+
+    const gchar * const msg[- AVAHI_ERR_MAX] = {
+        "OK",
+        "Operation failed",
+        "Bad state",
+        "Invalid host name",
+        "Invalid domain name",
+        "No suitable network protocol available",
+        "Invalid DNS TTL",
+        "Resource record key is pattern",
+        "Local name collision",
+        "Invalid record",
+        "Invalid service name",
+        "Invalid service type",
+        "Invalid port number",
+        "Invalid record key",
+        "Invalid address",
+        "Timeout reached",
+        "Too many clients",
+        "Too many objects",
+        "Too many entries",
+        "OS Error",
+        "Access denied"
+    };
+
+    return msg[-error];
+}
+
+gint avahi_server_errno(AvahiServer *s) {
+    g_assert(s);
+    
+    return s->error;
+}
+
+/* Just for internal use */
+gint avahi_server_set_errno(AvahiServer *s, gint error) {
+    g_assert(s);
+
+    return s->error = error;
+}
+
diff --git a/avahi-core/server.h b/avahi-core/server.h
index 7049f58..6572fbb 100644
--- a/avahi-core/server.h
+++ b/avahi-core/server.h
@@ -131,6 +131,8 @@ struct AvahiServer {
     /* Used for reflection of legacy unicast packets */
     AvahiLegacyUnicastReflectSlot **legacy_unicast_reflect_slots;
     guint16 legacy_unicast_reflect_id;
+
+    gint error;
 };
 
 gboolean avahi_server_entry_match_interface(AvahiEntry *e, AvahiInterface *i);
@@ -152,4 +154,6 @@ void avahi_host_rr_entry_group_callback(AvahiServer *s, AvahiEntryGroup *g, Avah
 void avahi_server_decrease_host_rr_pending(AvahiServer *s);
 void avahi_server_increase_host_rr_pending(AvahiServer *s);
 
+gint avahi_server_set_errno(AvahiServer *s, gint error);
+
 #endif