Implement event notifier send notification

[lttng-modules.git] / src / lttng-abi.c

diff --git a/src/lttng-abi.c b/src/lttng-abi.c
index 07c520f00a0c8d2604e0d170186621b35f46e2ae..6eb838752111ab207fe94dca18ece53fc85b0161 100644 (file)
--- a/src/lttng-abi.c
+++ b/src/lttng-abi.c
@@ -106,6 +106,14 @@ fd_error:
        return ret;
 }
 
+void event_notifier_send_notification_work_wakeup(struct irq_work *entry)
+{
+       struct lttng_event_notifier_group *event_notifier_group =
+                       container_of(entry, struct lttng_event_notifier_group,
+                                       wakeup_pending);
+       wake_up_interruptible(&event_notifier_group->read_wait);
+}
+
 static
 int lttng_abi_create_event_notifier_group(void)
 {
@@ -131,6 +139,9 @@ int lttng_abi_create_event_notifier_group(void)
        }
 
        event_notifier_group->file = event_notifier_group_file;
+       init_waitqueue_head(&event_notifier_group->read_wait);
+       init_irq_work(&event_notifier_group->wakeup_pending,
+                     event_notifier_send_notification_work_wakeup);
        fd_install(event_notifier_group_fd, event_notifier_group_file);
        return event_notifier_group_fd;
 
@@ -804,6 +815,10 @@ static const struct file_operations lttng_session_fops = {
 #endif
 };
 
+static const struct file_operations lttng_event_notifier_group_notif_fops = {
+       .owner = THIS_MODULE,
+};
+
 /**
  *     lttng_metadata_ring_buffer_poll - LTTng ring buffer poll file operation
  *     @filp: the file
@@ -1307,6 +1322,41 @@ nomem:
        return ret;
 }
 
+static
+int lttng_abi_open_event_notifier_group_stream(struct file *notif_file)
+{
+       struct lttng_event_notifier_group *event_notifier_group = notif_file->private_data;
+       struct channel *chan = event_notifier_group->chan;
+       struct lib_ring_buffer *buf;
+       int ret;
+       void *stream_priv;
+
+       buf = event_notifier_group->ops->buffer_read_open(chan);
+       if (!buf)
+               return -ENOENT;
+
+       /* The event_notifier notification fd holds a reference on the event_notifier group */
+       if (!atomic_long_add_unless(&notif_file->f_count, 1, LONG_MAX)) {
+               ret = -EOVERFLOW;
+               goto refcount_error;
+       }
+       event_notifier_group->buf = buf;
+       stream_priv = event_notifier_group;
+       ret = lttng_abi_create_stream_fd(notif_file, stream_priv,
+                       &lttng_event_notifier_group_notif_fops,
+                       "[lttng_event_notifier_stream]");
+       if (ret < 0)
+               goto fd_error;
+
+       return ret;
+
+fd_error:
+       atomic_long_dec(&notif_file->f_count);
+refcount_error:
+       event_notifier_group->ops->buffer_read_close(buf);
+       return ret;
+}
+
 static
 int lttng_abi_validate_event_param(struct lttng_kernel_event *event_param)
 {
@@ -1625,6 +1675,10 @@ long lttng_event_notifier_group_ioctl(struct file *file, unsigned int cmd,
                unsigned long arg)
 {
        switch (cmd) {
+       case LTTNG_KERNEL_EVENT_NOTIFIER_GROUP_NOTIFICATION_FD:
+       {
+               return lttng_abi_open_event_notifier_group_stream(file);
+       }
        case LTTNG_KERNEL_EVENT_NOTIFIER_CREATE:
        {
                struct lttng_kernel_event_notifier uevent_notifier_param;