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a6352fd4 MD |
1 | #ifndef _LIBRINGBUFFER_SHM_H |
2 | #define _LIBRINGBUFFER_SHM_H | |
3 | ||
4 | /* | |
5 | * libringbuffer/shm.h | |
6 | * | |
7 | * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
8 | * | |
9 | * Dual LGPL v2.1/GPL v2 license. | |
10 | */ | |
11 | ||
12 | #include <stdint.h> | |
1dbfff0c | 13 | #include <ust/usterr-signal-safe.h> |
a6352fd4 | 14 | #include "ust/core.h" |
1d498196 | 15 | #include "shm_types.h" |
a6352fd4 MD |
16 | |
17 | #define SHM_MAGIC 0x54335433 | |
18 | #define SHM_MAJOR 0 | |
19 | #define SHM_MINOR 1 | |
20 | ||
21 | /* | |
1d498196 MD |
22 | * Pointer dereferencing. We don't trust the shm_ref, so we validate |
23 | * both the index and offset with known boundaries. | |
a6352fd4 | 24 | */ |
a6352fd4 | 25 | static inline |
1d498196 | 26 | char *_shmp(struct shm_object_table *table, struct shm_ref *ref) |
a6352fd4 | 27 | { |
1d498196 MD |
28 | struct shm_object *obj; |
29 | size_t index, offset; | |
a6352fd4 | 30 | |
1d498196 MD |
31 | index = (size_t) ref->index; |
32 | if (unlikely(index >= table->allocated_len)) | |
33 | return NULL; | |
34 | obj = &table->objects[index]; | |
35 | offset = (size_t) ref->offset; | |
36 | if (unlikely(offset >= obj->memory_map_size)) | |
a6352fd4 | 37 | return NULL; |
1d498196 | 38 | return &obj->memory_map[offset]; |
a6352fd4 MD |
39 | } |
40 | ||
1d498196 MD |
41 | #define shmp(handle, ref) \ |
42 | ({ \ | |
43 | __typeof__((ref)._type) ____ptr_ret; \ | |
44 | ____ptr_ret = (__typeof__(____ptr_ret)) _shmp((handle)->table, &(ref)._ref); \ | |
45 | ____ptr_ret; \ | |
46 | }) | |
47 | ||
431d5cf0 | 48 | static inline |
1d498196 | 49 | void _set_shmp(struct shm_ref *ref, struct shm_ref src) |
431d5cf0 | 50 | { |
1d498196 | 51 | *ref = src; |
431d5cf0 MD |
52 | } |
53 | ||
1d498196 MD |
54 | #define set_shmp(ref, src) _set_shmp(&(ref)._ref, src) |
55 | ||
56 | struct shm_object_table *shm_object_table_create(size_t max_nb_obj); | |
57 | void shm_object_table_destroy(struct shm_object_table *table); | |
58 | struct shm_object *shm_object_table_append(struct shm_object_table *table, | |
59 | size_t memory_map_size); | |
60 | ||
61 | /* | |
62 | * zalloc_shm - allocate memory within a shm object. | |
63 | * | |
64 | * Shared memory is already zeroed by shmget. | |
65 | * *NOT* multithread-safe (should be protected by mutex). | |
66 | * Returns a -1, -1 tuple on error. | |
67 | */ | |
68 | struct shm_ref zalloc_shm(struct shm_object *obj, size_t len); | |
69 | void align_shm(struct shm_object *obj, size_t align); | |
70 | ||
a6352fd4 | 71 | #endif /* _LIBRINGBUFFER_SHM_H */ |