libust ABI: export streams

[lttng-ust.git] / libust / lttng-ust-abi.c

diff --git a/libust/lttng-ust-abi.c b/libust/lttng-ust-abi.c
index ccaa17fa9ba56bbf3a9cf8a81b0d134ca27fe1bb..0c0d6bb726f9c62804f9f17ee7f726bd5627bf93 100644 (file)
--- a/libust/lttng-ust-abi.c
+++ b/libust/lttng-ust-abi.c
@@ -204,6 +204,7 @@ static const struct objd_ops lttng_session_ops;
 static const struct objd_ops lttng_channel_ops;
 static const struct objd_ops lttng_metadata_ops;
 static const struct objd_ops lttng_event_ops;
+static const struct objd_ops lib_ring_buffer_objd_ops;
 
 enum channel_type {
        PER_CPU_CHANNEL,
@@ -505,35 +506,46 @@ static const struct objd_ops lttng_session_ops = {
        .cmd = lttng_session_cmd,
 };
 
-#if 0
+struct stream_priv_data {
+       struct lib_ring_buffer *buf;
+       struct ltt_channel *ltt_chan;
+};
+
 static
-int lttng_abi_open_stream(int channel_objd)
+int lttng_abi_open_stream(int channel_objd, struct lttng_ust_stream *info)
 {
        struct ltt_channel *channel = objd_private(channel_objd);
        struct lib_ring_buffer *buf;
+       struct stream_priv_data *priv;
        int stream_objd, ret;
 
-       buf = channel->ops->buffer_read_open(channel->chan);
+       buf = channel->ops->buffer_read_open(channel->chan, channel->handle,
+                       &info->shm_fd, &info->wait_fd, &info->memory_map_size);
        if (!buf)
                return -ENOENT;
 
-       stream_objd = objd_alloc(buf, &lib_ring_buffer_objd_ops);
+       priv = zmalloc(sizeof(*priv));
+       if (!priv) {
+               ret = -ENOMEM;
+               goto alloc_error;
+       }
+       priv->buf = buf;
+       priv->ltt_chan = channel;
+       stream_objd = objd_alloc(priv, &lib_ring_buffer_objd_ops);
        if (stream_objd < 0) {
                ret = stream_objd;
                goto objd_error;
        }
-       /*
-        * The stream holds a reference to the channel within the generic ring
-        * buffer library, so no need to hold a refcount on the channel and
-        * session files here.
-        */
+       /* Hold a reference on the channel object descriptor */
+       objd_ref(channel_objd);
        return stream_objd;
 
 objd_error:
-       channel->ops->buffer_read_close(buf);
+       free(priv);
+alloc_error:
+       channel->ops->buffer_read_close(buf, channel->handle);
        return ret;
 }
-#endif //0
 
 static
 int lttng_abi_create_event(int channel_objd,
@@ -603,8 +615,13 @@ long lttng_channel_cmd(int objd, unsigned int cmd, unsigned long arg)
 
        switch (cmd) {
        case LTTNG_UST_STREAM:
-               return -ENOSYS; //TODO
-               //return lttng_abi_open_stream(objd);
+       {
+               struct lttng_ust_stream *stream;
+
+               stream = (struct lttng_ust_stream *) arg;
+               /* stream used as output */
+               return lttng_abi_open_stream(objd, stream);
+       }
        case LTTNG_UST_EVENT:
                return lttng_abi_create_event(objd, (struct lttng_ust_event *) arg);
        case LTTNG_UST_CONTEXT:
@@ -638,8 +655,13 @@ long lttng_metadata_cmd(int objd, unsigned int cmd, unsigned long arg)
 {
        switch (cmd) {
        case LTTNG_UST_STREAM:
-               return -ENOSYS; //TODO
-               //return lttng_abi_open_stream(objd);
+       {
+               struct lttng_ust_stream *stream;
+
+               stream = (struct lttng_ust_stream *) arg;
+               /* stream used as output */
+               return lttng_abi_open_stream(objd, stream);
+       }
        default:
                return -EINVAL;
        }
@@ -696,6 +718,50 @@ static const struct objd_ops lttng_metadata_ops = {
        .cmd = lttng_metadata_cmd,
 };
 
+/**
+ *     lttng_rb_cmd - lttng ring buffer control through object descriptors
+ *
+ *     @objd: the object descriptor
+ *     @cmd: the command
+ *     @arg: command arg
+ *
+ *     This object descriptor implements lttng commands:
+ *             (None for now. Access is done directly though shm.)
+ *             TODO: Add buffer flush.
+ */
+static
+long lttng_rb_cmd(int objd, unsigned int cmd, unsigned long arg)
+{
+       struct stream_priv_data *priv = objd_private(objd);
+
+       switch (cmd) {
+       default:
+               return -EINVAL;
+       }
+}
+
+static
+int lttng_rb_release(int objd)
+{
+       struct stream_priv_data *priv = objd_private(objd);
+       struct lib_ring_buffer *buf;
+       struct ltt_channel *channel;
+
+       if (priv) {
+               buf = priv->buf;
+               channel = priv->ltt_chan;
+               free(priv);
+
+               return objd_unref(channel->objd);
+       }
+       return 0;
+}
+
+static const struct objd_ops lib_ring_buffer_objd_ops = {
+       .release = lttng_rb_release,
+       .cmd = lttng_rb_cmd,
+};
+
 /**
  *     lttng_event_cmd - lttng control through object descriptors
  *