adb: Handle adb connect in a thread

adb connect calls connect() in the event loop. If you pass a wrong ip
address or the server is slow to respond, this will block the event loop
and you can't even kill the adb server with adb kill-server. Handle connect
requests in a service thread instead.

Change-Id: I2ee732869a3dc22a6d3b87cf8ac80acaa7790037
diff --git a/adb/transport.c b/adb/transport.c
index b4abb66..224fe55 100644
--- a/adb/transport.c
+++ b/adb/transport.c
@@ -32,6 +32,11 @@
     .prev = &transport_list,
 };
 
+static atransport pending_list = {
+    .next = &pending_list,
+    .prev = &pending_list,
+};
+
 ADB_MUTEX_DEFINE( transport_lock );
 
 #if ADB_TRACE
@@ -645,8 +650,11 @@
         }
     }
 
-        /* put us on the master device list */
     adb_mutex_lock(&transport_lock);
+    /* remove from pending list */
+    t->next->prev = t->prev;
+    t->prev->next = t->next;
+    /* put us on the master device list */
     t->next = &transport_list;
     t->prev = transport_list.prev;
     t->next->prev = t;
@@ -989,9 +997,10 @@
 }
 #endif // ADB_HOST
 
-void register_socket_transport(int s, const char *serial, int port, int local)
+int register_socket_transport(int s, const char *serial, int port, int local)
 {
     atransport *t = calloc(1, sizeof(atransport));
+    atransport *n;
     char buff[32];
 
     if (!serial) {
@@ -999,15 +1008,37 @@
         serial = buff;
     }
     D("transport: %s init'ing for socket %d, on port %d\n", serial, s, port);
-    if ( init_socket_transport(t, s, port, local) < 0 ) {
-        adb_close(s);
+    if (init_socket_transport(t, s, port, local) < 0) {
         free(t);
-        return;
+        return -1;
     }
-    if(serial) {
-        t->serial = strdup(serial);
+
+    adb_mutex_lock(&transport_lock);
+    for (n = pending_list.next; n != &pending_list; n = n->next) {
+        if (n->serial && !strcmp(serial, n->serial)) {
+            adb_mutex_unlock(&transport_lock);
+            free(t);
+            return -1;
+        }
     }
+
+    for (n = transport_list.next; n != &transport_list; n = n->next) {
+        if (n->serial && !strcmp(serial, n->serial)) {
+            adb_mutex_unlock(&transport_lock);
+            free(t);
+            return -1;
+        }
+    }
+
+    t->next = &pending_list;
+    t->prev = pending_list.prev;
+    t->next->prev = t;
+    t->prev->next = t;
+    t->serial = strdup(serial);
+    adb_mutex_unlock(&transport_lock);
+
     register_transport(t);
+    return 0;
 }
 
 #if ADB_HOST
@@ -1077,6 +1108,14 @@
     if(devpath) {
         t->devpath = strdup(devpath);
     }
+
+    adb_mutex_lock(&transport_lock);
+    t->next = &pending_list;
+    t->prev = pending_list.prev;
+    t->next->prev = t;
+    t->prev->next = t;
+    adb_mutex_unlock(&transport_lock);
+
     register_transport(t);
 }