Revert to a hand-made select loop

This reverts commit c82dc29a
and 4d88a2ac.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

iohandler.c

@@ -81,64 +81,12 @@ int qemu_set_fd_handler2(int fd,
     return 0;
 }
 
-typedef struct IOTrampoline
-{
-    GIOChannel *chan;
-    IOHandler *fd_read;
-    IOHandler *fd_write;
-    void *opaque;
-    guint tag;
-} IOTrampoline;
-
-static gboolean fd_trampoline(GIOChannel *chan, GIOCondition cond, gpointer opaque)
-{
-    IOTrampoline *tramp = opaque;
-
-    if ((cond & G_IO_IN) && tramp->fd_read) {
-        tramp->fd_read(tramp->opaque);
-    }
-
-    if ((cond & G_IO_OUT) && tramp->fd_write) {
-        tramp->fd_write(tramp->opaque);
-    }
-
-    return TRUE;
-}
-
 int qemu_set_fd_handler(int fd,
                         IOHandler *fd_read,
                         IOHandler *fd_write,
                         void *opaque)
 {
-    static IOTrampoline fd_trampolines[FD_SETSIZE];
-    IOTrampoline *tramp = &fd_trampolines[fd];
-
-    if (tramp->tag != 0) {
-        g_io_channel_unref(tramp->chan);
-        g_source_remove(tramp->tag);
-        tramp->tag = 0;
-    }
-
-    if (fd_read || fd_write || opaque) {
-        GIOCondition cond = 0;
-
-        tramp->fd_read = fd_read;
-        tramp->fd_write = fd_write;
-        tramp->opaque = opaque;
-
-        if (fd_read) {
-            cond |= G_IO_IN | G_IO_ERR;
-        }
-
-        if (fd_write) {
-            cond |= G_IO_OUT | G_IO_ERR;
-        }
-
-        tramp->chan = g_io_channel_unix_new(fd);
-        tramp->tag = g_io_add_watch(tramp->chan, cond, fd_trampoline, tramp);
-    }
-
-    return 0;
+    return qemu_set_fd_handler2(fd, NULL, fd_read, fd_write, opaque);
 }
 
 void qemu_iohandler_fill(int *pnfds, fd_set *readfds, fd_set *writefds, fd_set *xfds)