common: move lttng_payload[_view] to libcommon

[lttng-tools.git] / src / common / payload.h

diff --git a/src/common/payload.h b/src/common/payload.h
new file mode 100644 (file)
index 0000000..3f1aa8c
--- /dev/null
+++ b/src/common/payload.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: LGPL-2.1-only
+ *
+ */
+
+#ifndef LTTNG_PAYLOAD_H
+#define LTTNG_PAYLOAD_H
+
+#include <common/dynamic-buffer.h>
+#include <common/dynamic-array.h>
+
+/*
+ * An lttng_payload encompasses the 'data' (bytes) and any passed file
+ * descriptors as part of a message between liblttng-ctl and the session
+ * daemon.
+ */
+struct lttng_payload {
+       struct lttng_dynamic_buffer buffer;
+       /* private */
+       struct lttng_dynamic_array _fds;
+};
+
+/*
+ * Initialize a payload. This performs no allocation and is meant
+ * to be used instead.
+ */
+LTTNG_HIDDEN
+void lttng_payload_init(struct lttng_payload *payload);
+
+/* Release any memory used by the payload. */
+LTTNG_HIDDEN
+void lttng_payload_reset(struct lttng_payload *payload);
+
+/**
+ * Add an fd to the payload.
+ * No ownership of the file descriptor is assumed by the payload.
+ *
+ * @payload    Payload instance
+ * @fd         File descriptor to add to the payload
+ *
+ * Returns 0 on success, -1 on allocation error.
+ */
+LTTNG_HIDDEN
+int lttng_payload_push_fd(struct lttng_payload *payload, int fd);
+
+#endif /* LTTNG_PAYLOAD_H */