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

#ifndef _LIBCOUNTER_SHM_H
#define _LIBCOUNTER_SHM_H

/*
 * libcounter/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 <stddef.h>
#include <stdint.h>
#include <unistd.h>
#include <usterr-signal-safe.h>
#include <urcu/compiler.h>
#include "shm_types.h"
#include "helper.h"

/* lttng_counter_handle_create - for UST. */
extern
struct lttng_counter_shm_handle *lttng_counter_handle_create(void *data,
				uint64_t memory_map_size, int wakeup_fd);
/* lttng_counter_handle_add_cpu - for UST. */
extern
int lttng_counter_handle_add_cpu(struct lttng_counter_shm_handle *handle,
		int shm_fd, uint32_t cpu_nr,
		uint64_t memory_map_size);
LTTNG_HIDDEN
unsigned int lttng_counter_handle_get_nr_cpus(struct lttng_counter_shm_handle *handle);

/*
 * 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 *_lttng_counter_shmp_offset(struct lttng_counter_shm_object_table *table,
		struct lttng_counter_shm_ref *ref,
		size_t idx, size_t elem_size)
{
	struct lttng_counter_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 lttng_counter_shmp_index(handle, ref, index)			\
	({								\
		__typeof__((ref)._type) ____ptr_ret;			\
		____ptr_ret = (__typeof__(____ptr_ret)) _lttng_counter_shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret));	\
		____ptr_ret;						\
	})

#define lttng_counter_shmp(handle, ref)	lttng_counter_shmp_index(handle, ref, 0)

static inline
void _lttng_counter_set_shmp(struct lttng_counter_shm_ref *ref, struct lttng_counter_shm_ref src)
{
	*ref = src;
}

#define lttng_counter_set_shmp(ref, src)	_lttng_counter_set_shmp(&(ref)._ref, src)

LTTNG_HIDDEN
struct lttng_counter_shm_object_table *lttng_counter_shm_object_table_create(size_t max_nb_obj);
LTTNG_HIDDEN
struct lttng_counter_shm_object *lttng_counter_shm_object_table_alloc(struct lttng_counter_shm_object_table *table,
			size_t memory_map_size,
			enum lttng_counter_shm_object_type type,
			const int cpu_fd,
			int cpu);
LTTNG_HIDDEN
struct lttng_counter_shm_object *lttng_counter_shm_object_table_append_shm(struct lttng_counter_shm_object_table *table,
			int shm_fd, size_t memory_map_size);
/* mem ownership is passed to lttng_counter_shm_object_table_append_mem(). */
LTTNG_HIDDEN
struct lttng_counter_shm_object *lttng_counter_shm_object_table_append_mem(struct lttng_counter_shm_object_table *table,
			void *mem, size_t memory_map_size);
LTTNG_HIDDEN
void lttng_counter_shm_object_table_destroy(struct lttng_counter_shm_object_table *table, int consumer);

/*
 * lttng_counter_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.
 */
LTTNG_HIDDEN
struct lttng_counter_shm_ref lttng_counter_zalloc_shm(struct lttng_counter_shm_object *obj, size_t len);
LTTNG_HIDDEN
void lttng_counter_align_shm(struct lttng_counter_shm_object *obj, size_t align);

static inline
int lttng_counter_shm_get_shm_fd(struct lttng_counter_shm_handle *handle, struct lttng_counter_shm_ref *ref)
{
	struct lttng_counter_shm_object_table *table = handle->table;
	struct lttng_counter_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 lttng_counter_shm_get_shm_size(struct lttng_counter_shm_handle *handle, struct lttng_counter_shm_ref *ref,
		uint64_t *size)
{
	struct lttng_counter_shm_object_table *table = handle->table;
	struct lttng_counter_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 /* _LIBCOUNTER_SHM_H */
Commit	Line	Data
ebabbf58 MD	1	#ifndef _LIBCOUNTER_SHM_H
	2	#define _LIBCOUNTER_SHM_H
	3
	4	/*
	5	* libcounter/shm.h
	6	*
	7	* Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	8	*
	9	* This library is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU Lesser General Public
	11	* License as published by the Free Software Foundation; only
	12	* version 2.1 of the License.
	13	*
	14	* This library is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	17	* Lesser General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU Lesser General Public
	20	* License along with this library; if not, write to the Free Software
	21	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	22	*/
	23
	24	#include <stddef.h>
	25	#include <stdint.h>
	26	#include <unistd.h>
	27	#include <usterr-signal-safe.h>
	28	#include <urcu/compiler.h>
	29	#include "shm_types.h"
3b098ac1	30	#include "helper.h"
ebabbf58 MD	31
	32	/* lttng_counter_handle_create - for UST. */
	33	extern
	34	struct lttng_counter_shm_handle lttng_counter_handle_create(void data,
	35	uint64_t memory_map_size, int wakeup_fd);
	36	/* lttng_counter_handle_add_cpu - for UST. */
	37	extern
	38	int lttng_counter_handle_add_cpu(struct lttng_counter_shm_handle *handle,
	39	int shm_fd, uint32_t cpu_nr,
	40	uint64_t memory_map_size);
3b098ac1	41	LTTNG_HIDDEN
ebabbf58 MD	42	unsigned int lttng_counter_handle_get_nr_cpus(struct lttng_counter_shm_handle *handle);
	43
	44	/*
	45	* Pointer dereferencing. We don't trust the shm_ref, so we validate
	46	* both the index and offset with known boundaries.
	47	*
	48	* "shmp" and "shmp_index" guarantee that it's safe to use the pointer
	49	* target type, even in the occurrence of shm_ref modification by an
	50	* untrusted process having write access to the shm_ref. We return a
	51	* NULL pointer if the ranges are invalid.
	52	*/
	53	static inline
	54	char _lttng_counter_shmp_offset(struct lttng_counter_shm_object_table table,
	55	struct lttng_counter_shm_ref *ref,
	56	size_t idx, size_t elem_size)
	57	{
	58	struct lttng_counter_shm_object *obj;
	59	size_t objindex, ref_offset;
	60
	61	objindex = (size_t) ref->index;
	62	if (caa_unlikely(objindex >= table->allocated_len))
	63	return NULL;
	64	obj = &table->objects[objindex];
	65	ref_offset = (size_t) ref->offset;
	66	ref_offset += idx * elem_size;
	67	/* Check if part of the element returned would exceed the limits. */
	68	if (caa_unlikely(ref_offset + elem_size > obj->memory_map_size))
	69	return NULL;
	70	return &obj->memory_map[ref_offset];
	71	}
	72
	73	#define lttng_counter_shmp_index(handle, ref, index) \
	74	({ \
	75	__typeof__((ref)._type) ____ptr_ret; \
	76	____ptr_ret = (__typeof__(____ptr_ret)) _lttng_counter_shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \
	77	____ptr_ret; \
	78	})
	79
	80	#define lttng_counter_shmp(handle, ref) lttng_counter_shmp_index(handle, ref, 0)
	81
	82	static inline
	83	void _lttng_counter_set_shmp(struct lttng_counter_shm_ref *ref, struct lttng_counter_shm_ref src)
	84	{
	85	*ref = src;
	86	}
	87
	88	#define lttng_counter_set_shmp(ref, src) _lttng_counter_set_shmp(&(ref)._ref, src)
	89
3b098ac1	90	LTTNG_HIDDEN
ebabbf58	91	struct lttng_counter_shm_object_table *lttng_counter_shm_object_table_create(size_t max_nb_obj);
3b098ac1	92	LTTNG_HIDDEN
ebabbf58 MD	93	struct lttng_counter_shm_object lttng_counter_shm_object_table_alloc(struct lttng_counter_shm_object_table table,
	94	size_t memory_map_size,
	95	enum lttng_counter_shm_object_type type,
	96	const int cpu_fd,
	97	int cpu);
3b098ac1	98	LTTNG_HIDDEN
ebabbf58 MD	99	struct lttng_counter_shm_object lttng_counter_shm_object_table_append_shm(struct lttng_counter_shm_object_table table,
	100	int shm_fd, size_t memory_map_size);
	101	/* mem ownership is passed to lttng_counter_shm_object_table_append_mem(). */
3b098ac1	102	LTTNG_HIDDEN
ebabbf58 MD	103	struct lttng_counter_shm_object lttng_counter_shm_object_table_append_mem(struct lttng_counter_shm_object_table table,
ebabbf58 MD	104	void *mem, size_t memory_map_size);
3b098ac1	105	LTTNG_HIDDEN
ebabbf58 MD	106	void lttng_counter_shm_object_table_destroy(struct lttng_counter_shm_object_table *table, int consumer);
	107
	108	/*
	109	* lttng_counter_zalloc_shm - allocate memory within a shm object.
	110	*
	111	* Shared memory is already zeroed by shmget.
	112	* NOT multithread-safe (should be protected by mutex).
	113	* Returns a -1, -1 tuple on error.
	114	*/
3b098ac1	115	LTTNG_HIDDEN
ebabbf58	116	struct lttng_counter_shm_ref lttng_counter_zalloc_shm(struct lttng_counter_shm_object *obj, size_t len);
3b098ac1	117	LTTNG_HIDDEN
ebabbf58 MD	118	void lttng_counter_align_shm(struct lttng_counter_shm_object *obj, size_t align);
	119
	120	static inline
	121	int lttng_counter_shm_get_shm_fd(struct lttng_counter_shm_handle handle, struct lttng_counter_shm_ref ref)
	122	{
	123	struct lttng_counter_shm_object_table *table = handle->table;
	124	struct lttng_counter_shm_object *obj;
	125	size_t index;
	126
	127	index = (size_t) ref->index;
	128	if (caa_unlikely(index >= table->allocated_len))
	129	return -EPERM;
	130	obj = &table->objects[index];
	131	return obj->shm_fd;
	132	}
	133
	134
	135	static inline
	136	int lttng_counter_shm_get_shm_size(struct lttng_counter_shm_handle handle, struct lttng_counter_shm_ref ref,
	137	uint64_t *size)
	138	{
	139	struct lttng_counter_shm_object_table *table = handle->table;
	140	struct lttng_counter_shm_object *obj;
	141	size_t index;
	142
	143	index = (size_t) ref->index;
	144	if (caa_unlikely(index >= table->allocated_len))
	145	return -EPERM;
	146	obj = &table->objects[index];
	147	*size = obj->memory_map_size;
	148	return 0;
	149	}
	150
	151	#endif /* _LIBCOUNTER_SHM_H */