5 files changed, 116 insertions, 0 deletions

diff --git a/include/os.h b/include/os.h
index 9937f2ea5..aed2e2f99 100644
--- a/include/os.h
+++ b/include/os.h
@@ -154,6 +154,19 @@ extern _X_EXPORT void AddEnabledDevice(int /*fd */ );
 
 extern _X_EXPORT void RemoveEnabledDevice(int /*fd */ );
 
+typedef void (*NotifyFdProcPtr)(int fd, int ready, void *data);
+
+#define X_NOTIFY_NONE   0
+#define X_NOTIFY_READ   1
+#define X_NOTIFY_WRITE  2
+
+extern _X_EXPORT Bool SetNotifyFd(int fd, NotifyFdProcPtr notify_fd, int mask, void *data);
+
+static inline void RemoveNotifyFd(int fd)
+{
+    (void) SetNotifyFd(fd, NULL, X_NOTIFY_NONE, NULL);
+}
+
 extern _X_EXPORT int OnlyListenToOneClient(ClientPtr /*client */ );
 
 extern _X_EXPORT void ListenToAllClients(void);
diff --git a/os/WaitFor.c b/os/WaitFor.c
index 732543086..12b21bb21 100644
--- a/os/WaitFor.c
+++ b/os/WaitFor.c
@@ -306,6 +306,10 @@ WaitForSomething(int *pClientsReady)
                 QueueWorkProc(EstablishNewConnections, NULL,
                               (void *) &LastSelectMask);
 
+            XFD_ANDSET(&tmp_set, &LastSelectMask, &NotifyReadFds);
+            if (XFD_ANYSET(&tmp_set))
+                HandleNotifyFds();
+
             if (XFD_ANYSET(&devicesReadable) || XFD_ANYSET(&clientsReadable))
                 break;
             /* check here for DDXes that queue events during Block/Wakeup */
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
diff --git a/os/osdep.h b/os/osdep.h
index 86263a53e..2bfc783f0 100644
--- a/os/osdep.h
+++ b/os/osdep.h
@@ -159,6 +159,10 @@ extern int FlushClient(ClientPtr /*who */ ,
 extern void FreeOsBuffers(OsCommPtr     /*oc */
     );
 
+extern void InitNotifyFds(void);
+
+extern void HandleNotifyFds(void);
+
 #include "dix.h"
 
 extern fd_set AllSockets;
@@ -166,6 +170,7 @@ extern fd_set AllClients;
 extern fd_set LastSelectMask;
 extern fd_set WellKnownConnections;
 extern fd_set EnabledDevices;
+extern fd_set NotifyReadFds;
 extern fd_set ClientsWithInput;
 extern fd_set ClientsWriteBlocked;
 extern fd_set OutputPending;
diff --git a/os/osinit.c b/os/osinit.c
index 6ec2f1167..54b39a0e8 100644
--- a/os/osinit.c
+++ b/os/osinit.c
@@ -314,6 +314,7 @@ OsInit(void)
         LockServer();
         been_here = TRUE;
     }
+    InitNotifyFds();
     TimerInit();
     OsVendorInit();
     OsResetSignals();