1 #ifndef _LIBRINGBUFFER_SHM_H
2 #define _LIBRINGBUFFER_SHM_H
7 * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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.
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.
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
27 #include <usterr-signal-safe.h>
28 #include <urcu/compiler.h>
29 #include "shm_types.h"
31 /* channel_handle_create - for UST. */
33 struct lttng_ust_shm_handle
*channel_handle_create(void *data
,
34 uint64_t memory_map_size
, int wakeup_fd
);
35 /* channel_handle_add_stream - for UST. */
37 int channel_handle_add_stream(struct lttng_ust_shm_handle
*handle
,
38 int shm_fd
, int wakeup_fd
, uint32_t stream_nr
,
39 uint64_t memory_map_size
);
40 unsigned int channel_handle_get_nr_streams(struct lttng_ust_shm_handle
*handle
);
42 void channel_destroy(struct channel
*chan
, struct lttng_ust_shm_handle
*handle
,
46 * Pointer dereferencing. We don't trust the shm_ref, so we validate
47 * both the index and offset with known boundaries.
49 * "shmp" and "shmp_index" guarantee that it's safe to use the pointer
50 * target type, even in the occurrence of shm_ref modification by an
51 * untrusted process having write access to the shm_ref. We return a
52 * NULL pointer if the ranges are invalid.
55 char *_shmp_offset(struct shm_object_table
*table
, struct shm_ref
*ref
,
56 size_t idx
, size_t elem_size
)
58 struct shm_object
*obj
;
59 size_t objindex
, ref_offset
;
61 objindex
= (size_t) ref
->index
;
62 if (caa_unlikely(objindex
>= table
->allocated_len
))
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
))
70 return &obj
->memory_map
[ref_offset
];
73 #define shmp_index(handle, ref, index) \
75 __typeof__((ref)._type) ____ptr_ret; \
76 ____ptr_ret = (__typeof__(____ptr_ret)) _shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \
80 #define shmp(handle, ref) shmp_index(handle, ref, 0)
83 void _set_shmp(struct shm_ref
*ref
, struct shm_ref src
)
88 #define set_shmp(ref, src) _set_shmp(&(ref)._ref, src)
90 struct shm_object_table
*shm_object_table_create(size_t max_nb_obj
);
91 struct shm_object
*shm_object_table_alloc(struct shm_object_table
*table
,
92 size_t memory_map_size
,
93 enum shm_object_type type
,
96 struct shm_object
*shm_object_table_append_shm(struct shm_object_table
*table
,
97 int shm_fd
, int wakeup_fd
, uint32_t stream_nr
,
98 size_t memory_map_size
);
99 /* mem ownership is passed to shm_object_table_append_mem(). */
100 struct shm_object
*shm_object_table_append_mem(struct shm_object_table
*table
,
101 void *mem
, size_t memory_map_size
, int wakeup_fd
);
102 void shm_object_table_destroy(struct shm_object_table
*table
, int consumer
);
105 * zalloc_shm - allocate memory within a shm object.
107 * Shared memory is already zeroed by shmget.
108 * *NOT* multithread-safe (should be protected by mutex).
109 * Returns a -1, -1 tuple on error.
111 struct shm_ref
zalloc_shm(struct shm_object
*obj
, size_t len
);
112 void align_shm(struct shm_object
*obj
, size_t align
);
115 int shm_get_wait_fd(struct lttng_ust_shm_handle
*handle
, struct shm_ref
*ref
)
117 struct shm_object_table
*table
= handle
->table
;
118 struct shm_object
*obj
;
121 index
= (size_t) ref
->index
;
122 if (caa_unlikely(index
>= table
->allocated_len
))
124 obj
= &table
->objects
[index
];
125 return obj
->wait_fd
[0];
129 int shm_get_wakeup_fd(struct lttng_ust_shm_handle
*handle
, struct shm_ref
*ref
)
131 struct shm_object_table
*table
= handle
->table
;
132 struct shm_object
*obj
;
135 index
= (size_t) ref
->index
;
136 if (caa_unlikely(index
>= table
->allocated_len
))
138 obj
= &table
->objects
[index
];
139 return obj
->wait_fd
[1];
143 int shm_close_wait_fd(struct lttng_ust_shm_handle
*handle
,
146 struct shm_object_table
*table
= handle
->table
;
147 struct shm_object
*obj
;
152 index
= (size_t) ref
->index
;
153 if (caa_unlikely(index
>= table
->allocated_len
))
155 obj
= &table
->objects
[index
];
156 wait_fd
= obj
->wait_fd
[0];
159 obj
->wait_fd
[0] = -1;
160 ret
= close(wait_fd
);
169 int shm_close_wakeup_fd(struct lttng_ust_shm_handle
*handle
,
172 struct shm_object_table
*table
= handle
->table
;
173 struct shm_object
*obj
;
178 index
= (size_t) ref
->index
;
179 if (caa_unlikely(index
>= table
->allocated_len
))
181 obj
= &table
->objects
[index
];
182 wakeup_fd
= obj
->wait_fd
[1];
185 obj
->wait_fd
[1] = -1;
186 ret
= close(wakeup_fd
);
195 int shm_get_shm_fd(struct lttng_ust_shm_handle
*handle
, struct shm_ref
*ref
)
197 struct shm_object_table
*table
= handle
->table
;
198 struct shm_object
*obj
;
201 index
= (size_t) ref
->index
;
202 if (caa_unlikely(index
>= table
->allocated_len
))
204 obj
= &table
->objects
[index
];
210 int shm_get_shm_size(struct lttng_ust_shm_handle
*handle
, struct shm_ref
*ref
,
213 struct shm_object_table
*table
= handle
->table
;
214 struct shm_object
*obj
;
217 index
= (size_t) ref
->index
;
218 if (caa_unlikely(index
>= table
->allocated_len
))
220 obj
= &table
->objects
[index
];
221 *size
= obj
->memory_map_size
;
225 #endif /* _LIBRINGBUFFER_SHM_H */
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