Modified mechanism to assign privileged ports and enable it for Windows as well

diff --git a/lib/socket.c b/lib/socket.c
index 71bb817f847f142aac2cbe53fa3efe33cb902c54..c64bf2eb7cad0f937169eb91a43e6aa02ae1dff3 100644 (file)
--- a/lib/socket.c
+++ b/lib/socket.c
@@ -362,8 +362,6 @@ static int rpc_connect_sockaddr_async(struct rpc_context *rpc, struct sockaddr_s
                return -1;
        }
 
-
-#if !defined(WIN32)
        /* Some systems allow you to set capabilities on an executable
         * to allow the file to be executed with privilege to bind to
         * privileged system ports, even if the user is not root.
@@ -378,32 +376,38 @@ static int rpc_connect_sockaddr_async(struct rpc_context *rpc, struct sockaddr_s
         * On linux, use
         *    sudo setcap 'cap_net_bind_service=+ep' /path/executable
         * to make the executable able to bind to a system port.
+        *
+        * On Windows, there is no concept of privileged ports. Thus
+        * binding will usually succeed.
         */
-       if (1) {
-               static int port = 200;
-               int i;
-               int one = 1;
-
-               setsockopt(rpc->fd, SOL_SOCKET, SO_REUSEADDR, (char *)&one, sizeof(one));
-
-               for (i = 0; i < 500; i++) {
-                       struct sockaddr_in sin;
-
-                       if(++port > 700) port = 200;
-
-                       memset(&sin, 0, sizeof(sin));
-                       sin.sin_port        = htons(port);
-                       sin.sin_family      = AF_INET;
-                       sin.sin_addr.s_addr = 0;
-
-                       if (bind(rpc->fd, (struct sockaddr *)&sin, sizeof(struct sockaddr_in)) != 0 && errno != EACCES) {
-                               /* we didnt get EACCES, so try again */
-                               continue;
+       {
+               struct sockaddr_in sin;
+               static int portOfs = 0;
+               const int firstPort = 512;      /* >= 512 according to Sun docs */
+               const int portCount = IPPORT_RESERVED - firstPort;
+               int startOfs = portOfs, port, rc;
+
+               do {
+                       rc = -1;
+                       port = htons(firstPort + portOfs);
+                       portOfs = (portOfs + 1) % portCount;
+
+                       /* skip well-known ports */
+                       if (!getservbyport(port, "tcp")) {
+                               memset(&sin, 0, sizeof(sin));
+                               sin.sin_port        = port;
+                               sin.sin_family      = AF_INET;
+                               sin.sin_addr.s_addr = 0;
+
+                               rc = bind(rpc->fd, (struct sockaddr *)&sin, sizeof(struct sockaddr_in));
+#if !defined(WIN32)
+                               /* we got EACCES, so don't try again */
+                               if (rc != 0 && errno == EACCES)
+                                       break;
+#endif
                        }
-                       break;
-               }
+               } while (rc != 0 && portOfs != startOfs);
        }
-#endif
 
        set_nonblocking(rpc->fd);