Only start discovery once per process.

Starting multiple Avahi threads in one process will fail with one of the
threads triggering an assert(), thus killing the process. It's not
critical that Avahi runs, so make sure we only start one.

diff --git a/src/meshlink.c b/src/meshlink.c
index d5ea5418e974c398ba181aa131dacf1cdd321df8..c7a6c0b2f3ad8d3e4fbf982c7a5951c50a4be6a5 100644 (file)
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -47,6 +47,9 @@ typedef struct {
 #define MSG_NOSIGNAL 0
 #endif
 
+static pthread_mutex_t global_mutex;
+static bool discovery_started;
+
 __thread meshlink_errno_t meshlink_errno;
 
 //TODO: this can go away completely
@@ -869,8 +872,16 @@ bool meshlink_start(meshlink_handle_t *mesh) {
        mesh->threadstarted=true;
 
        // Start discovery
-       if(!discovery_start(mesh))
-               return false;
+       // Since only one Avahi instance can run in one program at the moment, make sure we only start one, ignore it otherwise.
+
+       bool discovery_on = false;
+       pthread_mutex_lock(&global_mutex);
+       if(!discovery_started)
+               discovery_on = discovery_started = true;
+       pthread_mutex_unlock(&global_mutex);
+
+       if(discovery_on)
+               discovery_start(mesh);
 
        return true;
 }
@@ -883,7 +894,14 @@ void meshlink_stop(meshlink_handle_t *mesh) {
        }
 
        // Stop discovery
+
+       bool discovery_on = mesh->discovery_threadstarted;
        discovery_stop(mesh);
+       if(discovery_on) {
+               pthread_mutex_lock(&global_mutex);
+               discovery_started = false;
+               pthread_mutex_unlock(&global_mutex);
+       }
 
        // Shut down a listening socket to signal the main thread to shut down
 
@@ -1702,7 +1720,6 @@ extern void meshlink_hint_address(meshlink_handle_t *mesh, meshlink_node_t *node
        append_config_file(mesh, node->name, "Address", full_addr_str);
 
 fail:
-done:
        free(addr_str);
        free(port_str);
        free(full_addr_str);