#ifndef _LIBRINGBUFFER_SHM_H
#define _LIBRINGBUFFER_SHM_H
/*
* libringbuffer/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 <stdint.h>
#include <usterr-signal-safe.h>
#include <urcu/compiler.h>
#include "shm_types.h"
/* channel_handle_create - for UST. */
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. */
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);
unsigned int channel_handle_get_nr_streams(struct lttng_ust_shm_handle *handle);
extern
void channel_destroy(struct 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)
struct shm_object_table *shm_object_table_create(size_t max_nb_obj);
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);
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(). */
struct shm_object *shm_object_table_append_mem(struct shm_object_table *table,
void *mem, size_t memory_map_size, int wakeup_fd);
void shm_object_table_destroy(struct shm_object_table *table);
/*
* 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_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 */