Split socket creation and connect/listen

This will allow to assign the socket to a variable before connecting or
listening, so that it can be interrupted from another thread.

app/src/server.c

@@ -109,10 +109,10 @@ disable_tunnel(struct server *server) {
     return disable_tunnel_reverse(server->serial);
 }
 
-static sc_socket
-listen_on_port(uint16_t port) {
+static bool
+listen_on_port(sc_socket socket, uint16_t port) {
 #define IPV4_LOCALHOST 0x7F000001
-    return net_listen(IPV4_LOCALHOST, port, 1);
+    return net_listen(socket, IPV4_LOCALHOST, port, 1);
 }
 
 static bool
@@ -131,11 +131,17 @@ enable_tunnel_reverse_any_port(struct server *server,
         // client can listen before starting the server app, so there is no
         // need to try to connect until the server socket is listening on the
         // device.
-        server->server_socket = listen_on_port(port);
-        if (server->server_socket != SC_INVALID_SOCKET) {
-            // success
-            server->local_port = port;
-            return true;
+        sc_socket server_socket = net_socket();
+        if (server_socket != SC_INVALID_SOCKET) {
+            bool ok = listen_on_port(server_socket, port);
+            if (ok) {
+                // success
+                server->server_socket = server_socket;
+                server->local_port = port;
+                return true;
+            }
+
+            net_close(server_socket);
         }
 
         // failure, disable tunnel and try another port
@@ -291,11 +297,17 @@ execute_server(struct server *server, const struct server_params *params) {
 
 static sc_socket
 connect_and_read_byte(uint16_t port) {
-    sc_socket socket = net_connect(IPV4_LOCALHOST, port);
+    sc_socket socket = net_socket();
     if (socket == SC_INVALID_SOCKET) {
         return SC_INVALID_SOCKET;
     }
 
+    bool ok = net_connect(socket, IPV4_LOCALHOST, port);
+    if (!ok) {
+        net_close(socket);
+        return SC_INVALID_SOCKET;
+    }
+
     char byte;
     // the connection may succeed even if the server behind the "adb tunnel"
     // is not listening, so read one byte to detect a working connection
@@ -477,11 +489,16 @@ server_connect_to(struct server *server, char *device_name,
         }
 
         // we know that the device is listening, we don't need several attempts
-        server->control_socket =
-            net_connect(IPV4_LOCALHOST, server->local_port);
+        server->control_socket = net_socket();
         if (server->control_socket == SC_INVALID_SOCKET) {
             return false;
         }
+        bool ok = net_connect(server->control_socket, IPV4_LOCALHOST,
+                              server->local_port);
+        if (!ok) {
+            net_close(server->control_socket);
+            return false;
+        }
     }
 
     // we don't need the adb tunnel anymore

app/src/util/net.c

@@ -94,13 +94,18 @@ net_perror(const char *s) {
 }
 
 sc_socket
-net_connect(uint32_t addr, uint16_t port) {
+net_socket(void) {
     sc_raw_socket raw_sock = socket(AF_INET, SOCK_STREAM, 0);
     sc_socket sock = wrap(raw_sock);
     if (sock == SC_INVALID_SOCKET) {
         net_perror("socket");
-        return SC_INVALID_SOCKET;
     }
+    return sock;
+}
+
+bool
+net_connect(sc_socket socket, uint32_t addr, uint16_t port) {
+    sc_raw_socket raw_sock = unwrap(socket);
 
     SOCKADDR_IN sin;
     sin.sin_family = AF_INET;
@@ -109,21 +114,15 @@ net_connect(uint32_t addr, uint16_t port) {
 
     if (connect(raw_sock, (SOCKADDR *) &sin, sizeof(sin)) == SOCKET_ERROR) {
         net_perror("connect");
-        net_close(sock);
-        return SC_INVALID_SOCKET;
+        return false;
     }
 
-    return sock;
+    return true;
 }
 
-sc_socket
-net_listen(uint32_t addr, uint16_t port, int backlog) {
-    sc_raw_socket raw_sock = socket(AF_INET, SOCK_STREAM, 0);
-    sc_socket sock = wrap(raw_sock);
-    if (sock == SC_INVALID_SOCKET) {
-        net_perror("socket");
-        return SC_INVALID_SOCKET;
-    }
+bool
+net_listen(sc_socket socket, uint32_t addr, uint16_t port, int backlog) {
+    sc_raw_socket raw_sock = unwrap(socket);
 
     int reuse = 1;
     if (setsockopt(raw_sock, SOL_SOCKET, SO_REUSEADDR, (const void *) &reuse,
@@ -138,17 +137,15 @@ net_listen(uint32_t addr, uint16_t port, int backlog) {
 
     if (bind(raw_sock, (SOCKADDR *) &sin, sizeof(sin)) == SOCKET_ERROR) {
         net_perror("bind");
-        net_close(sock);
-        return SC_INVALID_SOCKET;
+        return false;
     }
 
     if (listen(raw_sock, backlog) == SOCKET_ERROR) {
         net_perror("listen");
-        net_close(sock);
-        return SC_INVALID_SOCKET;
+        return false;
     }
 
-    return sock;
+    return true;
 }
 
 sc_socket

app/src/util/net.h

@@ -31,10 +31,13 @@ void
 net_cleanup(void);
 
 sc_socket
-net_connect(uint32_t addr, uint16_t port);
+net_socket(void);
 
-sc_socket
-net_listen(uint32_t addr, uint16_t port, int backlog);
+bool
+net_connect(sc_socket socket, uint32_t addr, uint16_t port);
+
+bool
+net_listen(sc_socket socket, uint32_t addr, uint16_t port, int backlog);
 
 sc_socket
 net_accept(sc_socket server_socket);