sock: socket should be non-blocking

Event loop handles asynchronous connections.

src/sock.c

@@ -69,7 +69,7 @@ static int _in_progress(int error)
 #ifdef _WIN32
     return (error == WSAEWOULDBLOCK || error == WSAEINPROGRESS);
 #else
-    return (errno == EINPROGRESS);
+    return (error == EINPROGRESS);
 #endif
 }
 
@@ -80,8 +80,6 @@ sock_t sock_connect(const char * const host, const unsigned int port)
     struct addrinfo *res, *ainfo, hints;
     int err;
 
-    sock = -1;
-
     snprintf(service, 6, "%u", port);
 
     memset(&hints, 0, sizeof(struct addrinfo));
@@ -101,18 +99,19 @@ sock_t sock_connect(const char * const host, const unsigned int port)
         if (sock < 0)
             continue;
 
+        err = sock_set_nonblocking(sock);
+        if (err == 0) {
             err = connect(sock, ainfo->ai_addr, ainfo->ai_addrlen);
-        if (err < 0) {
+            if (err == 0 || _in_progress(sock_error()))
-            close(sock);
-            continue;
-        }
-
-        /* Connection has been established. */
                 break;
         }
-    freeaddrinfo(res);
 
-    return ainfo == NULL ? -1 : sock;
+        close(sock);
+    }
+    freeaddrinfo(res);
+    sock = ainfo == NULL ? -1 : sock;
+
+    return sock;
 }
 
 int sock_close(const sock_t sock)
@@ -130,7 +129,13 @@ int sock_set_blocking(const sock_t sock)
     u_long block = 0;
     return ioctlsocket(sock, FIONBIO, &block);
 #else
-    return fcntl(sock, F_SETFL, 0);
+    int rc;
+
+    rc = fcntl(sock, F_GETFL, NULL);
+    if (rc >= 0) {
+        rc = fcntl(sock, F_SETFL, rc & (~O_NONBLOCK));
+    }
+    return rc;
 #endif
 }
 
@@ -140,7 +145,13 @@ int sock_set_nonblocking(const sock_t sock)
     u_long nonblock = 1;
     return ioctlsocket(sock, FIONBIO, &nonblock);
 #else
-    return fcntl(sock, F_SETFL, O_NONBLOCK);
+    int rc;
+
+    rc = fcntl(sock, F_GETFL, NULL);
+    if (rc >= 0) {
+        rc = fcntl(sock, F_SETFL, rc | O_NONBLOCK);
+    }
+    return rc;
 #endif
 }
 
@@ -167,11 +178,11 @@ int sock_is_recoverable(const int error)
 int sock_connect_error(const sock_t sock)
 {
     struct sockaddr sa;
-    unsigned len;
+    socklen_t len;
     char temp;
 
+    memset(&sa, 0, sizeof(sa));
     sa.sa_family = AF_UNSPEC;
-
     len = sizeof(sa);
 
     /* we don't actually care about the peer name, we're just checking if