1 #ifndef _LIBRINGBUFFER_SHM_H
2 #define _LIBRINGBUFFER_SHM_H
7 * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
9 * Dual LGPL v2.1/GPL v2 license.
13 #include <ust/usterr-signal-safe.h>
15 #include "shm_types.h"
18 * Pointer dereferencing. We don't trust the shm_ref, so we validate
19 * both the index and offset with known boundaries.
22 char *_shmp_offset(struct shm_object_table
*table
, struct shm_ref
*ref
,
23 size_t idx
, size_t elem_size
)
25 struct shm_object
*obj
;
26 size_t objindex
, ref_offset
;
28 objindex
= (size_t) ref
->index
;
29 if (unlikely(objindex
>= table
->allocated_len
))
31 obj
= &table
->objects
[objindex
];
32 ref_offset
= (size_t) ref
->offset
;
33 ref_offset
+= idx
* elem_size
;
34 /* Check if part of the element returned would exceed the limits. */
35 if (unlikely(ref_offset
+ elem_size
> obj
->memory_map_size
))
37 return &obj
->memory_map
[ref_offset
];
40 #define shmp_index(handle, ref, index) \
42 __typeof__((ref)._type) ____ptr_ret; \
43 ____ptr_ret = (__typeof__(____ptr_ret)) _shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \
47 #define shmp(handle, ref) shmp_index(handle, ref, 0)
50 void _set_shmp(struct shm_ref
*ref
, struct shm_ref src
)
55 #define set_shmp(ref, src) _set_shmp(&(ref)._ref, src)
57 struct shm_object_table
*shm_object_table_create(size_t max_nb_obj
);
58 void shm_object_table_destroy(struct shm_object_table
*table
);
59 struct shm_object
*shm_object_table_append(struct shm_object_table
*table
,
60 size_t memory_map_size
);
63 * zalloc_shm - allocate memory within a shm object.
65 * Shared memory is already zeroed by shmget.
66 * *NOT* multithread-safe (should be protected by mutex).
67 * Returns a -1, -1 tuple on error.
69 struct shm_ref
zalloc_shm(struct shm_object
*obj
, size_t len
);
70 void align_shm(struct shm_object
*obj
, size_t align
);
73 int shm_get_wakeup_fd(struct shm_handle
*handle
, struct shm_ref
*ref
)
75 struct shm_object_table
*table
= handle
->table
;
76 struct shm_object
*obj
;
79 index
= (size_t) ref
->index
;
80 if (unlikely(index
>= table
->allocated_len
))
82 obj
= &table
->objects
[index
];
83 return obj
->wait_fd
[1];
88 int shm_get_wait_fd(struct shm_handle
*handle
, struct shm_ref
*ref
)
90 struct shm_object_table
*table
= handle
->table
;
91 struct shm_object
*obj
;
94 index
= (size_t) ref
->index
;
95 if (unlikely(index
>= table
->allocated_len
))
97 obj
= &table
->objects
[index
];
98 return obj
->wait_fd
[0];
101 #endif /* _LIBRINGBUFFER_SHM_H */
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