8f158e2f0507feeb8d05e000f08241a0e356b9e9
4 * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6 * Dual LGPL v2.1/GPL v2 license.
13 #include <sys/stat.h> /* For mode constants */
14 #include <fcntl.h> /* For O_* constants */
16 #include <ust/align.h>
18 struct shm_object_table
*shm_object_table_create(size_t max_nb_obj
)
20 struct shm_object_table
*table
;
22 table
= zmalloc(sizeof(struct shm_object_table
) +
23 max_nb_obj
* sizeof(table
->objects
[0]));
24 table
->size
= max_nb_obj
;
28 struct shm_object
*shm_object_table_append(struct shm_object_table
*table
,
29 size_t memory_map_size
)
31 int shmfd
, waitfd
[2], ret
, i
;
32 struct shm_object
*obj
;
35 if (table
->allocated_len
>= table
->size
)
37 obj
= &table
->objects
[table
->allocated_len
++];
39 /* wait_fd: create pipe */
45 for (i
= 0; i
< 2; i
++) {
46 ret
= fcntl(waitfd
[i
], F_SETFD
, FD_CLOEXEC
);
52 *obj
->wait_fd
= *waitfd
;
54 /* shm_fd: create shm */
57 * Allocate shm, and immediately unlink its shm oject, keeping
58 * only the file descriptor as a reference to the object. If it
59 * already exists (caused by short race window during which the
60 * global object exists in a concurrent shm_open), simply retry.
61 * We specifically do _not_ use the / at the beginning of the
62 * pathname so that some OS implementations can keep it local to
63 * the process (POSIX leaves this implementation-defined).
66 shmfd
= shm_open("ust-shm-tmp",
67 O_CREAT
| O_EXCL
| O_RDWR
, 0700);
68 } while (shmfd
< 0 && errno
== EEXIST
);
73 ret
= shm_unlink("ust-shm-tmp");
78 ret
= ftruncate(shmfd
, memory_map_size
);
85 /* memory_map: mmap */
86 memory_map
= mmap(NULL
, memory_map_size
, PROT_READ
| PROT_WRITE
,
87 MAP_SHARED
, shmfd
, 0);
88 if (memory_map
== MAP_FAILED
) {
92 obj
->memory_map
= memory_map
;
93 obj
->memory_map_size
= memory_map_size
;
94 obj
->allocated_len
= 0;
107 for (i
= 0; i
< 2; i
++) {
108 ret
= close(waitfd
[i
]);
121 void shmp_object_destroy(struct shm_object
*obj
)
125 ret
= munmap(obj
->memory_map
, obj
->memory_map_size
);
130 ret
= close(obj
->shm_fd
);
135 for (i
= 0; i
< 2; i
++) {
136 ret
= close(obj
->wait_fd
[i
]);
144 void shm_object_table_destroy(struct shm_object_table
*table
)
148 for (i
= 0; i
< table
->allocated_len
; i
++)
149 shmp_object_destroy(&table
->objects
[i
]);
154 * zalloc_shm - allocate memory within a shm object.
156 * Shared memory is already zeroed by shmget.
157 * *NOT* multithread-safe (should be protected by mutex).
158 * Returns a -1, -1 tuple on error.
160 struct shm_ref
zalloc_shm(struct shm_object
*obj
, size_t len
)
163 struct shm_ref shm_ref_error
= { -1, -1 };
165 if (obj
->memory_map_size
- obj
->allocated_len
< len
)
166 return shm_ref_error
;
167 ref
.index
= obj
->index
;
168 ref
.offset
= obj
->allocated_len
;
169 obj
->allocated_len
+= len
;
173 void align_shm(struct shm_object
*obj
, size_t align
)
175 size_t offset_len
= offset_align(obj
->allocated_len
, align
);
176 obj
->allocated_len
+= offset_len
;
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