[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 idx, size_t elem_size)
{
	struct shm_object *obj;
	size_t objindex, ref_offset;

	objindex = (size_t) ref->index;
	if (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 (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);
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
a6352fd4 MD	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>
1dbfff0c	13	#include <ust/usterr-signal-safe.h>
a6352fd4	14	#include "ust/core.h"
1d498196	15	#include "shm_types.h"
a6352fd4	16
a6352fd4	17	/*
1d498196 MD	18	* Pointer dereferencing. We don't trust the shm_ref, so we validate
1d498196 MD	19	* both the index and offset with known boundaries.
a6352fd4	20	*/
a6352fd4	21	static inline
4746ae29	22	char _shmp_offset(struct shm_object_table table, struct shm_ref *ref,
cba4b7a3	23	size_t idx, size_t elem_size)
a6352fd4	24	{
1d498196	25	struct shm_object *obj;
cba4b7a3	26	size_t objindex, ref_offset;
a6352fd4	27
cba4b7a3 MD	28	objindex = (size_t) ref->index;
cba4b7a3 MD	29	if (unlikely(objindex >= table->allocated_len))
1d498196	30	return NULL;
cba4b7a3	31	obj = &table->objects[objindex];
4746ae29	32	ref_offset = (size_t) ref->offset;
cba4b7a3 MD	33	ref_offset += idx * elem_size;
	34	/* Check if part of the element returned would exceed the limits. */
	35	if (unlikely(ref_offset + elem_size > obj->memory_map_size))
a6352fd4	36	return NULL;
4746ae29	37	return &obj->memory_map[ref_offset];
a6352fd4 MD	38	}
a6352fd4 MD	39
cba4b7a3	40	#define shmp_index(handle, ref, index) \
1d498196 MD	41	({ \
1d498196 MD	42	__typeof__((ref)._type) ____ptr_ret; \
cba4b7a3	43	____ptr_ret = (__typeof__(____ptr_ret)) _shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \
1d498196 MD	44	____ptr_ret; \
	45	})
	46
4746ae29 MD	47	#define shmp(handle, ref) shmp_index(handle, ref, 0)
4746ae29 MD	48
431d5cf0	49	static inline
1d498196	50	void _set_shmp(struct shm_ref *ref, struct shm_ref src)
431d5cf0	51	{
1d498196	52	*ref = src;
431d5cf0 MD	53	}
431d5cf0 MD	54
1d498196 MD	55	#define set_shmp(ref, src) _set_shmp(&(ref)._ref, src)
	56
	57	struct shm_object_table *shm_object_table_create(size_t max_nb_obj);
	58	void shm_object_table_destroy(struct shm_object_table *table);
	59	struct shm_object shm_object_table_append(struct shm_object_table table,
	60	size_t memory_map_size);
	61
	62	/*
	63	* zalloc_shm - allocate memory within a shm object.
	64	*
	65	* Shared memory is already zeroed by shmget.
	66	* NOT multithread-safe (should be protected by mutex).
	67	* Returns a -1, -1 tuple on error.
	68	*/
	69	struct shm_ref zalloc_shm(struct shm_object *obj, size_t len);
	70	void align_shm(struct shm_object *obj, size_t align);
	71
5d61a504 MD	72	static inline
	73	int shm_get_wakeup_fd(struct shm_handle handle, struct shm_ref ref)
	74	{
	75	struct shm_object_table *table = handle->table;
	76	struct shm_object *obj;
	77	size_t index;
	78
	79	index = (size_t) ref->index;
	80	if (unlikely(index >= table->allocated_len))
	81	return -EPERM;
	82	obj = &table->objects[index];
	83	return obj->wait_fd[1];
	84
	85	}
	86
	87	static inline
	88	int shm_get_wait_fd(struct shm_handle handle, struct shm_ref ref)
	89	{
	90	struct shm_object_table *table = handle->table;
	91	struct shm_object *obj;
	92	size_t index;
	93
	94	index = (size_t) ref->index;
	95	if (unlikely(index >= table->allocated_len))
	96	return -EPERM;
	97	obj = &table->objects[index];
	98	return obj->wait_fd[0];
	99	}
	100
a6352fd4	101	#endif /* _LIBRINGBUFFER_SHM_H */