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

/*
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#ifndef _LIBCOUNTER_SHM_H
#define _LIBCOUNTER_SHM_H

#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	1	/*
c0c0989a	2	* SPDX-License-Identifier: LGPL-2.1-only
ebabbf58 MD	3	*
ebabbf58 MD	4	* Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
ebabbf58 MD	5	*/
ebabbf58 MD	6
c0c0989a MJ	7	#ifndef _LIBCOUNTER_SHM_H
	8	#define _LIBCOUNTER_SHM_H
	9
ebabbf58 MD	10	#include <stddef.h>
	11	#include <stdint.h>
	12	#include <unistd.h>
	13	#include <usterr-signal-safe.h>
	14	#include <urcu/compiler.h>
	15	#include "shm_types.h"
3b098ac1	16	#include "helper.h"
ebabbf58 MD	17
	18	/* lttng_counter_handle_create - for UST. */
	19	extern
	20	struct lttng_counter_shm_handle lttng_counter_handle_create(void data,
	21	uint64_t memory_map_size, int wakeup_fd);
	22	/* lttng_counter_handle_add_cpu - for UST. */
	23	extern
	24	int lttng_counter_handle_add_cpu(struct lttng_counter_shm_handle *handle,
	25	int shm_fd, uint32_t cpu_nr,
	26	uint64_t memory_map_size);
3b098ac1	27	LTTNG_HIDDEN
ebabbf58 MD	28	unsigned int lttng_counter_handle_get_nr_cpus(struct lttng_counter_shm_handle *handle);
	29
	30	/*
	31	* Pointer dereferencing. We don't trust the shm_ref, so we validate
	32	* both the index and offset with known boundaries.
	33	*
	34	* "shmp" and "shmp_index" guarantee that it's safe to use the pointer
	35	* target type, even in the occurrence of shm_ref modification by an
	36	* untrusted process having write access to the shm_ref. We return a
	37	* NULL pointer if the ranges are invalid.
	38	*/
	39	static inline
	40	char _lttng_counter_shmp_offset(struct lttng_counter_shm_object_table table,
	41	struct lttng_counter_shm_ref *ref,
	42	size_t idx, size_t elem_size)
	43	{
	44	struct lttng_counter_shm_object *obj;
	45	size_t objindex, ref_offset;
	46
	47	objindex = (size_t) ref->index;
	48	if (caa_unlikely(objindex >= table->allocated_len))
	49	return NULL;
	50	obj = &table->objects[objindex];
	51	ref_offset = (size_t) ref->offset;
	52	ref_offset += idx * elem_size;
	53	/* Check if part of the element returned would exceed the limits. */
	54	if (caa_unlikely(ref_offset + elem_size > obj->memory_map_size))
	55	return NULL;
	56	return &obj->memory_map[ref_offset];
	57	}
	58
	59	#define lttng_counter_shmp_index(handle, ref, index) \
	60	({ \
	61	__typeof__((ref)._type) ____ptr_ret; \
	62	____ptr_ret = (__typeof__(____ptr_ret)) _lttng_counter_shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \
	63	____ptr_ret; \
	64	})
	65
	66	#define lttng_counter_shmp(handle, ref) lttng_counter_shmp_index(handle, ref, 0)
	67
	68	static inline
	69	void _lttng_counter_set_shmp(struct lttng_counter_shm_ref *ref, struct lttng_counter_shm_ref src)
	70	{
	71	*ref = src;
	72	}
	73
	74	#define lttng_counter_set_shmp(ref, src) _lttng_counter_set_shmp(&(ref)._ref, src)
	75
3b098ac1	76	LTTNG_HIDDEN
ebabbf58	77	struct lttng_counter_shm_object_table *lttng_counter_shm_object_table_create(size_t max_nb_obj);
3b098ac1	78	LTTNG_HIDDEN
ebabbf58 MD	79	struct lttng_counter_shm_object lttng_counter_shm_object_table_alloc(struct lttng_counter_shm_object_table table,
	80	size_t memory_map_size,
	81	enum lttng_counter_shm_object_type type,
	82	const int cpu_fd,
	83	int cpu);
3b098ac1	84	LTTNG_HIDDEN
ebabbf58 MD	85	struct lttng_counter_shm_object lttng_counter_shm_object_table_append_shm(struct lttng_counter_shm_object_table table,
	86	int shm_fd, size_t memory_map_size);
	87	/* mem ownership is passed to lttng_counter_shm_object_table_append_mem(). */
3b098ac1	88	LTTNG_HIDDEN
ebabbf58 MD	89	struct lttng_counter_shm_object lttng_counter_shm_object_table_append_mem(struct lttng_counter_shm_object_table table,
ebabbf58 MD	90	void *mem, size_t memory_map_size);
3b098ac1	91	LTTNG_HIDDEN
ebabbf58 MD	92	void lttng_counter_shm_object_table_destroy(struct lttng_counter_shm_object_table *table, int consumer);
	93
	94	/*
	95	* lttng_counter_zalloc_shm - allocate memory within a shm object.
	96	*
	97	* Shared memory is already zeroed by shmget.
	98	* NOT multithread-safe (should be protected by mutex).
	99	* Returns a -1, -1 tuple on error.
	100	*/
3b098ac1	101	LTTNG_HIDDEN
ebabbf58	102	struct lttng_counter_shm_ref lttng_counter_zalloc_shm(struct lttng_counter_shm_object *obj, size_t len);
3b098ac1	103	LTTNG_HIDDEN
ebabbf58 MD	104	void lttng_counter_align_shm(struct lttng_counter_shm_object *obj, size_t align);
	105
	106	static inline
	107	int lttng_counter_shm_get_shm_fd(struct lttng_counter_shm_handle handle, struct lttng_counter_shm_ref ref)
	108	{
	109	struct lttng_counter_shm_object_table *table = handle->table;
	110	struct lttng_counter_shm_object *obj;
	111	size_t index;
	112
	113	index = (size_t) ref->index;
	114	if (caa_unlikely(index >= table->allocated_len))
	115	return -EPERM;
	116	obj = &table->objects[index];
	117	return obj->shm_fd;
	118	}
	119
	120
	121	static inline
	122	int lttng_counter_shm_get_shm_size(struct lttng_counter_shm_handle handle, struct lttng_counter_shm_ref ref,
	123	uint64_t *size)
	124	{
	125	struct lttng_counter_shm_object_table *table = handle->table;
	126	struct lttng_counter_shm_object *obj;
	127	size_t index;
	128
	129	index = (size_t) ref->index;
	130	if (caa_unlikely(index >= table->allocated_len))
	131	return -EPERM;
	132	obj = &table->objects[index];
	133	*size = obj->memory_map_size;
	134	return 0;
	135	}
	136
	137	#endif /* _LIBCOUNTER_SHM_H */