[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_offset(struct shm_object_table *table, struct shm_ref *ref,
		   size_t offset)
{
	struct shm_object *obj;
	size_t index, ref_offset;

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

#define shmp_index(handle, ref, offset)					\
	({								\
		__typeof__((ref)._type) ____ptr_ret;			\
		____ptr_ret = (__typeof__(____ptr_ret)) _shmp_offset((handle)->table, &(ref)._ref, ((offset) * 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);
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_offset(struct shm_object_table table, struct shm_ref *ref,
	23	size_t offset)
	24	{
	25	struct shm_object *obj;
	26	size_t index, ref_offset;
	27
	28	index = (size_t) ref->index;
	29	if (unlikely(index >= table->allocated_len))
	30	return NULL;
	31	obj = &table->objects[index];
	32	ref_offset = (size_t) ref->offset;
	33	ref_offset += offset;
	34	if (unlikely(ref_offset >= obj->memory_map_size))
	35	return NULL;
	36	return &obj->memory_map[ref_offset];
	37	}
	38
	39	#define shmp_index(handle, ref, offset) \
	40	({ \
	41	__typeof__((ref)._type) ____ptr_ret; \
	42	____ptr_ret = (__typeof__(____ptr_ret)) _shmp_offset((handle)->table, &(ref)._ref, ((offset) * sizeof(*____ptr_ret))); \
	43	____ptr_ret; \
	44	})
	45
	46	#define shmp(handle, ref) shmp_index(handle, ref, 0)
	47
	48	static inline
	49	void _set_shmp(struct shm_ref *ref, struct shm_ref src)
	50	{
	51	*ref = src;
	52	}
	53
	54	#define set_shmp(ref, src) _set_shmp(&(ref)._ref, src)
	55
	56	struct shm_object_table *shm_object_table_create(size_t max_nb_obj);
	57	void shm_object_table_destroy(struct shm_object_table *table);
	58	struct shm_object shm_object_table_append(struct shm_object_table table,
	59	size_t memory_map_size);
	60
	61	/*
	62	* zalloc_shm - allocate memory within a shm object.
	63	*
	64	* Shared memory is already zeroed by shmget.
	65	* NOT multithread-safe (should be protected by mutex).
	66	* Returns a -1, -1 tuple on error.
	67	*/
	68	struct shm_ref zalloc_shm(struct shm_object *obj, size_t len);
	69	void align_shm(struct shm_object *obj, size_t align);
	70
	71	static inline
	72	int shm_get_wakeup_fd(struct shm_handle handle, struct shm_ref ref)
	73	{
	74	struct shm_object_table *table = handle->table;
	75	struct shm_object *obj;
	76	size_t index;
	77
	78	index = (size_t) ref->index;
	79	if (unlikely(index >= table->allocated_len))
	80	return -EPERM;
	81	obj = &table->objects[index];
	82	return obj->wait_fd[1];
	83
	84	}
	85
	86	static inline
	87	int shm_get_wait_fd(struct shm_handle handle, struct shm_ref ref)
	88	{
	89	struct shm_object_table *table = handle->table;
	90	struct shm_object *obj;
	91	size_t index;
	92
	93	index = (size_t) ref->index;
	94	if (unlikely(index >= table->allocated_len))
	95	return -EPERM;
	96	obj = &table->objects[index];
	97	return obj->wait_fd[0];
	98	}
	99
	100	#endif /* _LIBRINGBUFFER_SHM_H */