[lttng-ust.git] / libringbuffer / shm.h

#ifndef _LIBRINGBUFFER_SHM_H
#define _LIBRINGBUFFER_SHM_H

/*
 * libringbuffer/shm.h
 *
 * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Dual LGPL v2.1/GPL v2 license.
 */

#include <stdint.h>
#include <ust/usterr-signal-safe.h>
#include "ust/core.h"
#include "shm_types.h"

/*
 * Pointer dereferencing. We don't trust the shm_ref, so we validate
 * both the index and offset with known boundaries.
 */
static inline
char *_shmp(struct shm_object_table *table, struct shm_ref *ref)
{
	struct shm_object *obj;
	size_t index, offset;

	index = (size_t) ref->index;
	if (unlikely(index >= table->allocated_len))
		return NULL;
	obj = &table->objects[index];
	offset = (size_t) ref->offset;
	if (unlikely(offset >= obj->memory_map_size))
		return NULL;
	return &obj->memory_map[offset];
}

#define shmp(handle, ref)						\
	({								\
		__typeof__((ref)._type) ____ptr_ret;			\
		____ptr_ret = (__typeof__(____ptr_ret)) _shmp((handle)->table, &(ref)._ref);	\
		____ptr_ret;						\
	})

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);
void shm_object_table_destroy(struct shm_object_table *table);
struct shm_object *shm_object_table_append(struct shm_object_table *table,
					   size_t memory_map_size);

/*
 * 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_wakeup_fd(struct 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 (unlikely(index >= table->allocated_len))
		return -EPERM;
	obj = &table->objects[index];
	return obj->wait_fd[1];

}

static inline
int shm_get_wait_fd(struct 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 (unlikely(index >= table->allocated_len))
		return -EPERM;
	obj = &table->objects[index];
	return obj->wait_fd[0];
}

#endif /* _LIBRINGBUFFER_SHM_H */
Commit	Line	Data
	1	#ifndef _LIBRINGBUFFER_SHM_H
	2	#define _LIBRINGBUFFER_SHM_H
	3
	4	/*
	5	* libringbuffer/shm.h
	6	*
	7	* Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	8	*
	9	* Dual LGPL v2.1/GPL v2 license.
	10	*/
	11
	12	#include <stdint.h>
	13	#include <ust/usterr-signal-safe.h>
	14	#include "ust/core.h"
	15	#include "shm_types.h"
	16
	17	/*
	18	* Pointer dereferencing. We don't trust the shm_ref, so we validate
	19	* both the index and offset with known boundaries.
	20	*/
	21	static inline
	22	char _shmp(struct shm_object_table table, struct shm_ref *ref)
	23	{
	24	struct shm_object *obj;
	25	size_t index, offset;
	26
	27	index = (size_t) ref->index;
	28	if (unlikely(index >= table->allocated_len))
	29	return NULL;
	30	obj = &table->objects[index];
	31	offset = (size_t) ref->offset;
	32	if (unlikely(offset >= obj->memory_map_size))
	33	return NULL;
	34	return &obj->memory_map[offset];
	35	}
	36
	37	#define shmp(handle, ref) \
	38	({ \
	39	__typeof__((ref)._type) ____ptr_ret; \
	40	____ptr_ret = (__typeof__(____ptr_ret)) _shmp((handle)->table, &(ref)._ref); \
	41	____ptr_ret; \
	42	})
	43
	44	static inline
	45	void _set_shmp(struct shm_ref *ref, struct shm_ref src)
	46	{
	47	*ref = src;
	48	}
	49
	50	#define set_shmp(ref, src) _set_shmp(&(ref)._ref, src)
	51
	52	struct shm_object_table *shm_object_table_create(size_t max_nb_obj);
	53	void shm_object_table_destroy(struct shm_object_table *table);
	54	struct shm_object shm_object_table_append(struct shm_object_table table,
	55	size_t memory_map_size);
	56
	57	/*
	58	* zalloc_shm - allocate memory within a shm object.
	59	*
	60	* Shared memory is already zeroed by shmget.
	61	* NOT multithread-safe (should be protected by mutex).
	62	* Returns a -1, -1 tuple on error.
	63	*/
	64	struct shm_ref zalloc_shm(struct shm_object *obj, size_t len);
	65	void align_shm(struct shm_object *obj, size_t align);
	66
	67	static inline
	68	int shm_get_wakeup_fd(struct shm_handle handle, struct shm_ref ref)
	69	{
	70	struct shm_object_table *table = handle->table;
	71	struct shm_object *obj;
	72	size_t index;
	73
	74	index = (size_t) ref->index;
	75	if (unlikely(index >= table->allocated_len))
	76	return -EPERM;
	77	obj = &table->objects[index];
	78	return obj->wait_fd[1];
	79
	80	}
	81
	82	static inline
	83	int shm_get_wait_fd(struct shm_handle handle, struct shm_ref ref)
	84	{
	85	struct shm_object_table *table = handle->table;
	86	struct shm_object *obj;
	87	size_t index;
	88
	89	index = (size_t) ref->index;
	90	if (unlikely(index >= table->allocated_len))
	91	return -EPERM;
	92	obj = &table->objects[index];
	93	return obj->wait_fd[0];
	94	}
	95
	96	#endif /* _LIBRINGBUFFER_SHM_H */