Fix: sessiond: ODR violation results in memory corruption

[lttng-tools.git] / src / common / fd-tracker / utils-poll.cpp

/*
 * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 */

#include <common/compat/poll.hpp>

#include "utils.hpp"

#ifdef HAVE_EPOLL

namespace {
struct create_args {
	struct lttng_poll_event *events;
	int size;
	int flags;
};
} /* namespace */

static int open_epoll(void *data, int *out_fd)
{
	int ret;
	struct create_args *args = (create_args *) data;

	ret = lttng_poll_create(args->events, args->size, args->flags);
	if (ret < 0) {
		goto end;
	}

	*out_fd = args->events->epfd;
end:
	return ret;
}

static int close_epoll(void *data, int *in_fd __attribute__((unused)))
{
	/* Will close the epfd. */
	lttng_poll_clean((struct lttng_poll_event *) data);
	return 0;
}

/*
 * The epoll variant of the poll compat layer creates an unsuspendable fd which
 * must be tracked.
 */
int fd_tracker_util_poll_create(struct fd_tracker *tracker,
		const char *name,
		struct lttng_poll_event *events,
		int size,
		int flags)
{
	int out_fd;
	struct create_args create_args = {
		.events = events,
		.size = size,
		.flags = flags,
	};

	return fd_tracker_open_unsuspendable_fd(
			tracker, &out_fd, &name, 1, open_epoll, &create_args);
}

int fd_tracker_util_poll_clean(
		struct fd_tracker *tracker, struct lttng_poll_event *events)
{
	return fd_tracker_close_unsuspendable_fd(
			tracker, &events->epfd, 1, close_epoll, events);
}

#else /* HAVE_EPOLL */

/*
 * The epoll variant of the poll compat layer creates an unsuspendable fd which
 * must be tracked.
 */
int fd_tracker_util_poll_create(
		struct fd_tracker *tracker __attribute__((unused)),
		const char *name __attribute__((unused)),
		struct lttng_poll_event *events,
		int size,
		int flags __attribute__((unused)))
{
	return lttng_poll_create(events, size, flags);
}

int fd_tracker_util_poll_clean(
		struct fd_tracker *tracker __attribute__((unused)),
		struct lttng_poll_event *events)
{
	lttng_poll_clean(events);
	return 0;
}

#endif /* !HAVE_EPOLL */