1 files changed, 93 insertions, 0 deletions
diff --git a/os/connection.c b/os/connection.c
index 3d33c4170..0df439189 100644
--- a/os/connection.c
+++ b/os/connection.c
@@ -123,6 +123,7 @@ static int lastfdesc;           /* maximum file descriptor */
 
 fd_set WellKnownConnections;    /* Listener mask */
 fd_set EnabledDevices;          /* mask for input devices that are on */
+fd_set NotifyReadFds;           /* mask for other file descriptors */
 fd_set AllSockets;              /* select on this */
 fd_set AllClients;              /* available clients */
 fd_set LastSelectMask;          /* mask returned from last select call */
@@ -1090,6 +1091,98 @@ RemoveEnabledDevice(int fd)
     RemoveGeneralSocket(fd);
 }
 
+struct notify_fd {
+    struct xorg_list list;
+    int fd;
+    int mask;
+    NotifyFdProcPtr notify;
+    void *data;
+};
+
+static struct xorg_list notify_fds;
+
+void
+InitNotifyFds(void)
+{
+    struct notify_fd *s, *next;
+    static int been_here;
+
+    if (been_here)
+        xorg_list_for_each_entry_safe(s, next, &notify_fds, list)
+            RemoveNotifyFd(s->fd);
+
+    xorg_list_init(&notify_fds);
+    been_here = 1;
+}
+
+/*****************
+ * SetNotifyFd
+ *    Registers a callback to be invoked when the specified
+ *    file descriptor becomes readable.
+ *****************/
+
+Bool
+SetNotifyFd(int fd, NotifyFdProcPtr notify, int mask, void *data)
+{
+    struct notify_fd *n;
+    int changes;
+
+    xorg_list_for_each_entry(n, &notify_fds, list)
+        if (n->fd == fd)
+            break;
+
+    if (&n->list == &notify_fds) {
+        if (mask == 0)
+            return TRUE;
+
+        n = calloc(1, sizeof (struct notify_fd));
+        if (!n)
+            return FALSE;
+        n->fd = fd;
+        xorg_list_add(&n->list, &notify_fds);
+    }
+
+    changes = n->mask ^ mask;
+
+    if (changes & X_NOTIFY_READ) {
+        if (mask & X_NOTIFY_READ) {
+            FD_SET(fd, &NotifyReadFds);
+            AddGeneralSocket(fd);
+        } else {
+            RemoveGeneralSocket(fd);
+            FD_CLR(fd, &NotifyReadFds);
+        }
+    }
+    if (mask == 0) {
+        xorg_list_del(&n->list);
+        free(n);
+    } else {
+        n->mask = mask;
+        n->data = data;
+        n->notify = notify;
+    }
+
+    return TRUE;
+}
+
+/*****************
+ * HandlNotifyFds
+ *    A WorkProc to be called when any of the registered
+ *    file descriptors are readable.
+ *****************/
+
+void
+HandleNotifyFds(void)
+{
+    struct notify_fd *s, *next;
+
+    xorg_list_for_each_entry_safe(s, next, &notify_fds, list) {
+        if (FD_ISSET(s->fd, &LastSelectMask)) {
+            s->notify(s->fd, X_NOTIFY_READ, s->data);
+        }
+    }
+}
+
 /*****************
  * OnlyListenToOneClient:
  *    Only accept requests from  one client.  Continue to handle new