/*
* libringbuffer/shm.h
*
- * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
- * Dual LGPL v2.1/GPL v2 license.
+ * 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 <ust/usterr-signal-safe.h>
-#include "ust/core.h"
+#include <usterr-signal-safe.h>
+#include <urcu/compiler.h>
#include "shm_types.h"
-#define SHM_MAGIC 0x54335433
-#define SHM_MAJOR 0
-#define SHM_MINOR 1
-
/*
* 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(struct shm_object_table *table, struct shm_ref *ref)
+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 index, offset;
+ size_t objindex, ref_offset;
- index = (size_t) ref->index;
- if (unlikely(index >= table->allocated_len))
+ objindex = (size_t) ref->index;
+ if (caa_unlikely(objindex >= table->allocated_len))
return NULL;
- obj = &table->objects[index];
- offset = (size_t) ref->offset;
- if (unlikely(offset >= obj->memory_map_size))
+ 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[offset];
+ return &obj->memory_map[ref_offset];
}
-#define shmp(handle, ref) \
+#define shmp_index(handle, ref, index) \
({ \
__typeof__((ref)._type) ____ptr_ret; \
- ____ptr_ret = (__typeof__(____ptr_ret)) _shmp((handle)->table, &(ref)._ref); \
+ ____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)
{
#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_append_shadow(struct shm_object_table *table,
+ int shm_fd, int wait_fd, size_t memory_map_size);
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);
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 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_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_object_data(struct lttng_ust_shm_handle *handle, struct shm_ref *ref,
+ int **shm_fd, char **shm_path,
+ int **wait_fd, char **wait_pipe_path,
+ uint64_t **memory_map_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];
+ *shm_fd = &obj->shm_fd;
+ *shm_path = obj->shm_path;
+ *wait_fd = &obj->wait_fd[0];
+ *wait_pipe_path = obj->wait_pipe_path;
+ *memory_map_size = &obj->allocated_len;
+ return 0;
+}
+
#endif /* _LIBRINGBUFFER_SHM_H */
projects / lttng-ust.git / blobdiff