Don't hold the xlib-xcb lock while sleeping: that allows deadlock.

[free-sw/xcb/libxcb] / src / xcb_conn.c

diff --git a/src/xcb_conn.c b/src/xcb_conn.c
index 827a12b..e7856c3 100644 (file)
--- a/src/xcb_conn.c
+++ b/src/xcb_conn.c
@@ -288,15 +288,33 @@ void _xcb_unlock_io(xcb_connection_t *c)
     pthread_mutex_unlock(&c->iolock);
 }
 
+void _xcb_wait_io(xcb_connection_t *c, pthread_cond_t *cond)
+{
+    int xlib_locked = c->xlib.lock;
+    if(xlib_locked)
+    {
+        c->xlib.lock = 0;
+        pthread_cond_broadcast(&c->xlib.cond);
+    }
+    pthread_cond_wait(cond, &c->iolock);
+    if(xlib_locked)
+    {
+        while(c->xlib.lock)
+            pthread_cond_wait(&c->xlib.cond, &c->iolock);
+        c->xlib.lock = 1;
+        c->xlib.thread = pthread_self();
+    }
+}
+
 int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vector, int *count)
 {
-    int ret;
+    int ret, xlib_locked;
     fd_set rfds, wfds;
 
     /* If the thing I should be doing is already being done, wait for it. */
     if(count ? c->out.writing : c->in.reading)
     {
-        pthread_cond_wait(cond, &c->iolock);
+        _xcb_wait_io(c, cond);
         return 1;
     }
 
@@ -311,6 +329,12 @@ int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vec
         ++c->out.writing;
     }
 
+    xlib_locked = c->xlib.lock;
+    if(xlib_locked)
+    {
+        c->xlib.lock = 0;
+        pthread_cond_broadcast(&c->xlib.cond);
+    }
     _xcb_unlock_io(c);
     do {
        ret = select(c->fd + 1, &rfds, &wfds, 0, 0);
@@ -321,6 +345,11 @@ int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vec
        ret = 0;
     }
     _xcb_lock_io(c);
+    if(xlib_locked)
+    {
+        c->xlib.lock = 1;
+        c->xlib.thread = pthread_self();
+    }
 
     if(ret)
     {