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

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

#ifndef _LIBRINGBUFFER_SHM_H
#define _LIBRINGBUFFER_SHM_H

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

/* channel_handle_create - for UST. */
__attribute__((visibility("hidden")))
extern
struct lttng_ust_shm_handle *channel_handle_create(void *data,
				uint64_t memory_map_size, int wakeup_fd);

/* channel_handle_add_stream - for UST. */
__attribute__((visibility("hidden")))
extern
int channel_handle_add_stream(struct lttng_ust_shm_handle *handle,
		int shm_fd, int wakeup_fd, uint32_t stream_nr,
		uint64_t memory_map_size);

__attribute__((visibility("hidden")))
unsigned int channel_handle_get_nr_streams(struct lttng_ust_shm_handle *handle);

__attribute__((visibility("hidden")))
extern
void channel_destroy(struct lttng_ust_lib_ring_buffer_channel *chan,
		struct lttng_ust_shm_handle *handle,
		int consumer);

/*
 * 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 *_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 (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 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)

__attribute__((visibility("hidden")))
struct shm_object_table *shm_object_table_create(size_t max_nb_obj);

__attribute__((visibility("hidden")))
struct shm_object *shm_object_table_alloc(struct shm_object_table *table,
			size_t memory_map_size,
			enum shm_object_type type,
			const int stream_fd,
			int cpu);

__attribute__((visibility("hidden")))
struct shm_object *shm_object_table_append_shm(struct shm_object_table *table,
			int shm_fd, int wakeup_fd, uint32_t stream_nr,
			size_t memory_map_size);

/* mem ownership is passed to shm_object_table_append_mem(). */
__attribute__((visibility("hidden")))
struct shm_object *shm_object_table_append_mem(struct shm_object_table *table,
			void *mem, size_t memory_map_size, int wakeup_fd);

__attribute__((visibility("hidden")))
void shm_object_table_destroy(struct shm_object_table *table, int consumer);

/*
 * 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.
 */
__attribute__((visibility("hidden")))
struct shm_ref zalloc_shm(struct shm_object *obj, size_t len);

__attribute__((visibility("hidden")))
void align_shm(struct shm_object *obj, size_t align);

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

static inline
int shm_get_wakeup_fd(struct lttng_ust_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 (caa_unlikely(index >= table->allocated_len))
		return -EPERM;
	obj = &table->objects[index];
	return obj->wait_fd[1];
}

static inline
int shm_close_wait_fd(struct lttng_ust_shm_handle *handle,
		struct shm_ref *ref)
{
	struct shm_object_table *table = handle->table;
	struct shm_object *obj;
	int wait_fd;
	size_t index;
	int ret;

	index = (size_t) ref->index;
	if (caa_unlikely(index >= table->allocated_len))
		return -EPERM;
	obj = &table->objects[index];
	wait_fd = obj->wait_fd[0];
	if (wait_fd < 0)
		return -ENOENT;
	obj->wait_fd[0] = -1;
	ret = close(wait_fd);
	if (ret) {
		ret = -errno;
		return ret;
	}
	return 0;
}

static inline
int shm_close_wakeup_fd(struct lttng_ust_shm_handle *handle,
		struct shm_ref *ref)
{
	struct shm_object_table *table = handle->table;
	struct shm_object *obj;
	int wakeup_fd;
	size_t index;
	int ret;

	index = (size_t) ref->index;
	if (caa_unlikely(index >= table->allocated_len))
		return -EPERM;
	obj = &table->objects[index];
	wakeup_fd = obj->wait_fd[1];
	if (wakeup_fd < 0)
		return -ENOENT;
	obj->wait_fd[1] = -1;
	ret = close(wakeup_fd);
	if (ret) {
		ret = -errno;
		return ret;
	}
	return 0;
}

static inline
int shm_get_shm_fd(struct lttng_ust_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 (caa_unlikely(index >= table->allocated_len))
		return -EPERM;
	obj = &table->objects[index];
	return obj->shm_fd;
}


static inline
int shm_get_shm_size(struct lttng_ust_shm_handle *handle, struct shm_ref *ref,
		uint64_t *size)
{
	struct shm_object_table *table = handle->table;
	struct 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 /* _LIBRINGBUFFER_SHM_H */
Commit	Line	Data
	1	/*
	2	* SPDX-License-Identifier: LGPL-2.1-only
	3	*
	4	* Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*/
	6
	7	#ifndef _LIBRINGBUFFER_SHM_H
	8	#define _LIBRINGBUFFER_SHM_H
	9
	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"
	16
	17	/* channel_handle_create - for UST. */
	18	__attribute__((visibility("hidden")))
	19	extern
	20	struct lttng_ust_shm_handle channel_handle_create(void data,
	21	uint64_t memory_map_size, int wakeup_fd);
	22
	23	/* channel_handle_add_stream - for UST. */
	24	__attribute__((visibility("hidden")))
	25	extern
	26	int channel_handle_add_stream(struct lttng_ust_shm_handle *handle,
	27	int shm_fd, int wakeup_fd, uint32_t stream_nr,
	28	uint64_t memory_map_size);
	29
	30	__attribute__((visibility("hidden")))
	31	unsigned int channel_handle_get_nr_streams(struct lttng_ust_shm_handle *handle);
	32
	33	__attribute__((visibility("hidden")))
	34	extern
	35	void channel_destroy(struct lttng_ust_lib_ring_buffer_channel *chan,
	36	struct lttng_ust_shm_handle *handle,
	37	int consumer);
	38
	39	/*
	40	* Pointer dereferencing. We don't trust the shm_ref, so we validate
	41	* both the index and offset with known boundaries.
	42	*
	43	* "shmp" and "shmp_index" guarantee that it's safe to use the pointer
	44	* target type, even in the occurrence of shm_ref modification by an
	45	* untrusted process having write access to the shm_ref. We return a
	46	* NULL pointer if the ranges are invalid.
	47	*/
	48	static inline
	49	char _shmp_offset(struct shm_object_table table, struct shm_ref *ref,
	50	size_t idx, size_t elem_size)
	51	{
	52	struct shm_object *obj;
	53	size_t objindex, ref_offset;
	54
	55	objindex = (size_t) ref->index;
	56	if (caa_unlikely(objindex >= table->allocated_len))
	57	return NULL;
	58	obj = &table->objects[objindex];
	59	ref_offset = (size_t) ref->offset;
	60	ref_offset += idx * elem_size;
	61	/* Check if part of the element returned would exceed the limits. */
	62	if (caa_unlikely(ref_offset + elem_size > obj->memory_map_size))
	63	return NULL;
	64	return &obj->memory_map[ref_offset];
	65	}
	66
	67	#define shmp_index(handle, ref, index) \
	68	({ \
	69	__typeof__((ref)._type) ____ptr_ret; \
	70	____ptr_ret = (__typeof__(____ptr_ret)) _shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \
	71	____ptr_ret; \
	72	})
	73
	74	#define shmp(handle, ref) shmp_index(handle, ref, 0)
	75
	76	static inline
	77	void _set_shmp(struct shm_ref *ref, struct shm_ref src)
	78	{
	79	*ref = src;
	80	}
	81
	82	#define set_shmp(ref, src) _set_shmp(&(ref)._ref, src)
	83
	84	__attribute__((visibility("hidden")))
	85	struct shm_object_table *shm_object_table_create(size_t max_nb_obj);
	86
	87	__attribute__((visibility("hidden")))
	88	struct shm_object shm_object_table_alloc(struct shm_object_table table,
	89	size_t memory_map_size,
	90	enum shm_object_type type,
	91	const int stream_fd,
	92	int cpu);
	93
	94	__attribute__((visibility("hidden")))
	95	struct shm_object shm_object_table_append_shm(struct shm_object_table table,
	96	int shm_fd, int wakeup_fd, uint32_t stream_nr,
	97	size_t memory_map_size);
	98
	99	/* mem ownership is passed to shm_object_table_append_mem(). */
	100	__attribute__((visibility("hidden")))
	101	struct shm_object shm_object_table_append_mem(struct shm_object_table table,
	102	void *mem, size_t memory_map_size, int wakeup_fd);
	103
	104	__attribute__((visibility("hidden")))
	105	void shm_object_table_destroy(struct shm_object_table *table, int consumer);
	106
	107	/*
	108	* zalloc_shm - allocate memory within a shm object.
	109	*
	110	* Shared memory is already zeroed by shmget.
	111	* NOT multithread-safe (should be protected by mutex).
	112	* Returns a -1, -1 tuple on error.
	113	*/
	114	__attribute__((visibility("hidden")))
	115	struct shm_ref zalloc_shm(struct shm_object *obj, size_t len);
	116
	117	__attribute__((visibility("hidden")))
	118	void align_shm(struct shm_object *obj, size_t align);
	119
	120	static inline
	121	int shm_get_wait_fd(struct lttng_ust_shm_handle handle, struct shm_ref ref)
	122	{
	123	struct shm_object_table *table = handle->table;
	124	struct 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->wait_fd[0];
	132	}
	133
	134	static inline
	135	int shm_get_wakeup_fd(struct lttng_ust_shm_handle handle, struct shm_ref ref)
	136	{
	137	struct shm_object_table *table = handle->table;
	138	struct shm_object *obj;
	139	size_t index;
	140
	141	index = (size_t) ref->index;
	142	if (caa_unlikely(index >= table->allocated_len))
	143	return -EPERM;
	144	obj = &table->objects[index];
	145	return obj->wait_fd[1];
	146	}
	147
	148	static inline
	149	int shm_close_wait_fd(struct lttng_ust_shm_handle *handle,
	150	struct shm_ref *ref)
	151	{
	152	struct shm_object_table *table = handle->table;
	153	struct shm_object *obj;
	154	int wait_fd;
	155	size_t index;
	156	int ret;
	157
	158	index = (size_t) ref->index;
	159	if (caa_unlikely(index >= table->allocated_len))
	160	return -EPERM;
	161	obj = &table->objects[index];
	162	wait_fd = obj->wait_fd[0];
	163	if (wait_fd < 0)
	164	return -ENOENT;
	165	obj->wait_fd[0] = -1;
	166	ret = close(wait_fd);
	167	if (ret) {
	168	ret = -errno;
	169	return ret;
	170	}
	171	return 0;
	172	}
	173
	174	static inline
	175	int shm_close_wakeup_fd(struct lttng_ust_shm_handle *handle,
	176	struct shm_ref *ref)
	177	{
	178	struct shm_object_table *table = handle->table;
	179	struct shm_object *obj;
	180	int wakeup_fd;
	181	size_t index;
	182	int ret;
	183
	184	index = (size_t) ref->index;
	185	if (caa_unlikely(index >= table->allocated_len))
	186	return -EPERM;
	187	obj = &table->objects[index];
	188	wakeup_fd = obj->wait_fd[1];
	189	if (wakeup_fd < 0)
	190	return -ENOENT;
	191	obj->wait_fd[1] = -1;
	192	ret = close(wakeup_fd);
	193	if (ret) {
	194	ret = -errno;
	195	return ret;
	196	}
	197	return 0;
	198	}
	199
	200	static inline
	201	int shm_get_shm_fd(struct lttng_ust_shm_handle handle, struct shm_ref ref)
	202	{
	203	struct shm_object_table *table = handle->table;
	204	struct shm_object *obj;
	205	size_t index;
	206
	207	index = (size_t) ref->index;
	208	if (caa_unlikely(index >= table->allocated_len))
	209	return -EPERM;
	210	obj = &table->objects[index];
	211	return obj->shm_fd;
	212	}
	213
	214
	215	static inline
	216	int shm_get_shm_size(struct lttng_ust_shm_handle handle, struct shm_ref ref,
	217	uint64_t *size)
	218	{
	219	struct shm_object_table *table = handle->table;
	220	struct shm_object *obj;
	221	size_t index;
	222
	223	index = (size_t) ref->index;
	224	if (caa_unlikely(index >= table->allocated_len))
	225	return -EPERM;
	226	obj = &table->objects[index];
	227	*size = obj->memory_map_size;
	228	return 0;
	229	}
	230
	231	#endif /* _LIBRINGBUFFER_SHM_H */