SoW-2019-0002: Dynamic Snapshot

[lttng-tools.git] / src / common / actions / start-session.c

/*
 * Copyright (C) 2019 EfficiOS, Inc.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License, version 2.1 only,
 * as published by the Free Software Foundation.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <assert.h>
#include <common/error.h>
#include <common/macros.h>
#include <lttng/action/action-internal.h>
#include <lttng/action/start-session-internal.h>
#include <lttng/action/start-session.h>

struct lttng_action_start_session {
	struct lttng_action parent;

	/* Owned by this. */
	char *session_name;
};

struct lttng_action_start_session_comm {
	/* Includes the trailing \0. */
	uint32_t session_name_len;

	/*
	 * Variable data:
	 *
	 *  - session name (null terminated)
	 */
	char data[];
} LTTNG_PACKED;

static struct lttng_action_start_session *action_start_session_from_action(
		struct lttng_action *action)
{
	assert(action);

	return container_of(action, struct lttng_action_start_session, parent);
}

static const struct lttng_action_start_session *action_start_session_from_action_const(
		const struct lttng_action *action)
{
	assert(action);

	return container_of(action, struct lttng_action_start_session, parent);
}

static bool lttng_action_start_session_validate(struct lttng_action *action)
{
	bool valid;
	struct lttng_action_start_session *action_start_session;

	if (!action) {
		valid = false;
		goto end;
	}

	action_start_session = action_start_session_from_action(action);

	/* A non-empty session name is mandatory. */
	if (!action_start_session->session_name ||
			strlen(action_start_session->session_name) == 0) {
		valid = false;
		goto end;
	}

	valid = true;
end:
	return valid;
}

static bool lttng_action_start_session_is_equal(const struct lttng_action *_a, const struct lttng_action *_b)
{
	bool is_equal = false;
	struct lttng_action_start_session *a, *b;

	a = container_of(_a, struct lttng_action_start_session, parent);
	b = container_of(_b, struct lttng_action_start_session, parent);

	/* Action is not valid if this is not true. */
	assert(a->session_name);
	assert(b->session_name);
	if (strcmp(a->session_name, b->session_name)) {
		goto end;
	}

	is_equal = true;
end:
	return is_equal;
}

static int lttng_action_start_session_serialize(
		struct lttng_action *action, struct lttng_dynamic_buffer *buf)
{
	struct lttng_action_start_session *action_start_session;
	struct lttng_action_start_session_comm comm;
	size_t session_name_len;
	int ret;

	assert(action);
	assert(buf);

	action_start_session = action_start_session_from_action(action);

	assert(action_start_session->session_name);

	DBG("Serializing start session action: session-name: %s",
			action_start_session->session_name);

	session_name_len = strlen(action_start_session->session_name) + 1;
	comm.session_name_len = session_name_len;

	ret = lttng_dynamic_buffer_append(buf, &comm, sizeof(comm));
	if (ret) {
		ret = -1;
		goto end;
	}

	ret = lttng_dynamic_buffer_append(buf,
			action_start_session->session_name, session_name_len);
	if (ret) {
		ret = -1;
		goto end;
	}

	ret = 0;
end:
	return ret;
}

static void lttng_action_start_session_destroy(struct lttng_action *action)
{
	struct lttng_action_start_session *action_start_session;

	if (!action) {
		goto end;
	}

	action_start_session = action_start_session_from_action(action);

	free(action_start_session->session_name);
	free(action_start_session);

end:
	return;
}

ssize_t lttng_action_start_session_create_from_buffer(
		const struct lttng_buffer_view *view,
		struct lttng_action **p_action)
{
	ssize_t consumed_len;
	struct lttng_action_start_session_comm *comm;
	const char *session_name;
	struct lttng_action *action;
	enum lttng_action_status status;

	action = lttng_action_start_session_create();
	if (!action) {
		consumed_len = -1;
		goto end;
	}

	comm = (struct lttng_action_start_session_comm *) view->data;
	session_name = (const char *) &comm->data;

	if (!lttng_buffer_view_validate_string(
			    view, session_name, comm->session_name_len)) {
		consumed_len = -1;
		goto end;
	}

	status = lttng_action_start_session_set_session_name(
			action, session_name);
	if (status != LTTNG_ACTION_STATUS_OK) {
		consumed_len = -1;
		goto end;
	}

	consumed_len = sizeof(struct lttng_action_start_session_comm) +
		       comm->session_name_len;
	*p_action = action;
	action = NULL;

end:
	lttng_action_start_session_destroy(action);

	return consumed_len;
}

struct lttng_action *lttng_action_start_session_create(void)
{
	struct lttng_action *action;

	action = zmalloc(sizeof(struct lttng_action_start_session));
	if (!action) {
		goto end;
	}

	lttng_action_init(action, LTTNG_ACTION_TYPE_START_SESSION,
			lttng_action_start_session_validate,
			lttng_action_start_session_serialize,
			lttng_action_start_session_is_equal,
			lttng_action_start_session_destroy);

end:
	return action;
}

enum lttng_action_status lttng_action_start_session_set_session_name(
		struct lttng_action *action, const char *session_name)
{
	struct lttng_action_start_session *action_start_session;
	enum lttng_action_status status;

	if (!action || !session_name || strlen(session_name) == 0) {
		status = LTTNG_ACTION_STATUS_INVALID;
		goto end;
	}

	action_start_session = action_start_session_from_action(action);

	free(action_start_session->session_name);

	action_start_session->session_name = strdup(session_name);
	if (!action_start_session->session_name) {
		status = LTTNG_ACTION_STATUS_ERROR;
		goto end;
	}

	status = LTTNG_ACTION_STATUS_OK;
end:
	return status;
}

enum lttng_action_status lttng_action_start_session_get_session_name(
		const struct lttng_action *action, const char **session_name)
{
	const struct lttng_action_start_session *action_start_session;
	enum lttng_action_status status;

	if (!action || !session_name) {
		status = LTTNG_ACTION_STATUS_INVALID;
		goto end;
	}

	action_start_session = action_start_session_from_action_const(action);

	*session_name = action_start_session->session_name;

	status = LTTNG_ACTION_STATUS_OK;
end:
	return status;
}