#ifndef _LIBRINGBUFFER_SHM_H

#define _LIBRINGBUFFER_SHM_H

/*

 * libringbuffer/shm.h

 *

 * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; only

 * version 2.1 of the License.

 *

 * 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 <stdint.h>

#include <usterr-signal-safe.h>

#include <urcu/compiler.h>

#include "shm_types.h"

/* channel_handle_create - for UST. */

extern

struct lttng_ust_shm_handle *channel_handle_create(void *data,

				uint64_t memory_map_size, int wakeup_fd);

/* channel_handle_add_stream - for UST. */

extern

int channel_handle_add_stream(struct lttng_ust_shm_handle *handle,

		int shm_fd, int wakeup_fd, uint32_t stream_nr,

		uint64_t memory_map_size);

unsigned int channel_handle_get_nr_streams(struct lttng_ust_shm_handle *handle);

extern

void channel_destroy(struct channel *chan, struct lttng_ust_shm_handle *handle,

		int consumer);

/*

 * Pointer dereferencing. We don't trust the shm_ref, so we validate

 * both the index and offset with known boundaries.

 *

 * "shmp" and "shmp_index" guarantee that it's safe to use the pointer

 * target type, even in the occurrence of shm_ref modification by an

 * untrusted process having write access to the shm_ref. We return a

 * NULL pointer if the ranges are invalid.

 */

static inline

char *_shmp_offset(struct shm_object_table *table, struct shm_ref *ref,

		   size_t idx, size_t elem_size)

{

	struct shm_object *obj;

	size_t objindex, ref_offset;

	objindex = (size_t) ref->index;

	if (caa_unlikely(objindex >= table->allocated_len))

		return NULL;

	obj = &table->objects[objindex];

	ref_offset = (size_t) ref->offset;

	ref_offset += idx * elem_size;

	/* Check if part of the element returned would exceed the limits. */

	if (caa_unlikely(ref_offset + elem_size > obj->memory_map_size))

		return NULL;

	return &obj->memory_map[ref_offset];

}

#define shmp_index(handle, ref, index)					\

	({								\

		__typeof__((ref)._type) ____ptr_ret;			\

		____ptr_ret = (__typeof__(____ptr_ret)) _shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret));	\

		____ptr_ret;						\

	})

#define shmp(handle, ref)	shmp_index(handle, ref, 0)

static inline

void _set_shmp(struct shm_ref *ref, struct shm_ref src)

{

	*ref = src;

}

#define set_shmp(ref, src)	_set_shmp(&(ref)._ref, src)

struct shm_object_table *shm_object_table_create(size_t max_nb_obj);

struct shm_object *shm_object_table_alloc(struct shm_object_table *table,

			size_t memory_map_size,

			enum shm_object_type type,

			const int stream_fd);

struct shm_object *shm_object_table_append_shm(struct shm_object_table *table,

			int shm_fd, int wakeup_fd, uint32_t stream_nr,

			size_t memory_map_size);

/* mem ownership is passed to shm_object_table_append_mem(). */

struct shm_object *shm_object_table_append_mem(struct shm_object_table *table,

			void *mem, size_t memory_map_size, int wakeup_fd);

void shm_object_table_destroy(struct shm_object_table *table);

/*

 * zalloc_shm - allocate memory within a shm object.

 *

 * Shared memory is already zeroed by shmget.

 * *NOT* multithread-safe (should be protected by mutex).

 * Returns a -1, -1 tuple on error.

 */

struct shm_ref zalloc_shm(struct shm_object *obj, size_t len);

void align_shm(struct shm_object *obj, size_t align);

static inline

int shm_get_wait_fd(struct lttng_ust_shm_handle *handle, struct shm_ref *ref)

{

	struct shm_object_table *table = handle->table;

	struct shm_object *obj;

	size_t index;

	index = (size_t) ref->index;

	if (caa_unlikely(index >= table->allocated_len))

		return -EPERM;

	obj = &table->objects[index];

	return obj->wait_fd[0];

}

static inline

int shm_get_wakeup_fd(struct lttng_ust_shm_handle *handle, struct shm_ref *ref)

{

	struct shm_object_table *table = handle->table;

	struct shm_object *obj;

	size_t index;

	index = (size_t) ref->index;

	if (caa_unlikely(index >= table->allocated_len))

		return -EPERM;

	obj = &table->objects[index];

	return obj->wait_fd[1];

}

static inline

int shm_close_wait_fd(struct lttng_ust_shm_handle *handle,

		struct shm_ref *ref)

{

	struct shm_object_table *table = handle->table;

	struct shm_object *obj;

	int wait_fd;

	size_t index;

	int ret;

	index = (size_t) ref->index;

	if (caa_unlikely(index >= table->allocated_len))

		return -EPERM;

	obj = &table->objects[index];

	wait_fd = obj->wait_fd[0];

	if (wait_fd < 0)

		return -ENOENT;

	obj->wait_fd[0] = -1;

	ret = close(wait_fd);

	if (ret) {

		ret = -errno;

		return ret;

	}

	return 0;

}

static inline

int shm_close_wakeup_fd(struct lttng_ust_shm_handle *handle,

		struct shm_ref *ref)

{

	struct shm_object_table *table = handle->table;

	struct shm_object *obj;

	int wakeup_fd;

	size_t index;

	int ret;

	index = (size_t) ref->index;

	if (caa_unlikely(index >= table->allocated_len))

		return -EPERM;

	obj = &table->objects[index];

	wakeup_fd = obj->wait_fd[1];

	if (wakeup_fd < 0)

		return -ENOENT;

	obj->wait_fd[1] = -1;

	ret = close(wakeup_fd);

	if (ret) {

		ret = -errno;

		return ret;

	}

	return 0;

}

static inline

int shm_get_shm_fd(struct lttng_ust_shm_handle *handle, struct shm_ref *ref)

{

	struct shm_object_table *table = handle->table;

	struct shm_object *obj;

	size_t index;

	index = (size_t) ref->index;

	if (caa_unlikely(index >= table->allocated_len))

		return -EPERM;

	obj = &table->objects[index];

	return obj->shm_fd;

}

static inline

int shm_get_shm_size(struct lttng_ust_shm_handle *handle, struct shm_ref *ref,

		uint64_t *size)

{

	struct shm_object_table *table = handle->table;

	struct shm_object *obj;

	size_t index;

	index = (size_t) ref->index;

	if (caa_unlikely(index >= table->allocated_len))

		return -EPERM;

	obj = &table->objects[index];

	*size = obj->memory_map_size;

	return 0;

}

#endif /* _LIBRINGBUFFER_SHM_H */