2 * SPDX-License-Identifier: LGPL-2.1-only
4 * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
12 #include <sys/types.h>
13 #include <sys/stat.h> /* For mode constants */
14 #include <fcntl.h> /* For O_* constants */
28 #include <lttng/ust-utils.h>
30 #include <ust-helper.h>
35 * Ensure we have the required amount of space available by writing 0
36 * into the entire buffer. Not doing so can trigger SIGBUS when going
37 * beyond the available shm space.
40 int zero_file(int fd
, size_t len
)
48 pagelen
= sysconf(_SC_PAGESIZE
);
51 zeropage
= calloc(pagelen
, 1);
55 while (len
> written
) {
57 retlen
= write(fd
, zeropage
,
58 min_t(size_t, pagelen
, len
- written
));
59 } while (retlen
== -1UL && errno
== EINTR
);
72 struct shm_object_table
*shm_object_table_create(size_t max_nb_obj
)
74 struct shm_object_table
*table
;
76 table
= zmalloc(sizeof(struct shm_object_table
) +
77 max_nb_obj
* sizeof(table
->objects
[0]));
80 table
->size
= max_nb_obj
;
85 struct shm_object
*_shm_object_table_alloc_shm(struct shm_object_table
*table
,
86 size_t memory_map_size
,
89 int shmfd
, waitfd
[2], ret
, i
;
90 struct shm_object
*obj
;
95 if (table
->allocated_len
>= table
->size
)
97 obj
= &table
->objects
[table
->allocated_len
];
99 /* wait_fd: create pipe */
105 for (i
= 0; i
< 2; i
++) {
106 ret
= fcntl(waitfd
[i
], F_SETFD
, FD_CLOEXEC
);
112 /* The write end of the pipe needs to be non-blocking */
113 ret
= fcntl(waitfd
[1], F_SETFL
, O_NONBLOCK
);
118 memcpy(obj
->wait_fd
, waitfd
, sizeof(waitfd
));
121 * Set POSIX shared memory object size
123 * First, use ftruncate() to set its size, some implementations won't
124 * allow writes past the size set by ftruncate.
125 * Then, use write() to fill it with zeros, this allows us to fully
126 * allocate it and detect a shortage of shm space without dealing with
131 ret
= ftruncate(shmfd
, memory_map_size
);
134 goto error_ftruncate
;
136 ret
= zero_file(shmfd
, memory_map_size
);
139 goto error_zero_file
;
143 * Also ensure the file metadata is synced with the storage by using
144 * fsync(2). Some platforms don't allow fsync on POSIX shm fds, ignore
145 * EINVAL accordingly.
148 if (ret
&& errno
!= EINVAL
) {
152 obj
->shm_fd_ownership
= 0;
155 /* memory_map: mmap */
156 memory_map
= mmap(NULL
, memory_map_size
, PROT_READ
| PROT_WRITE
,
157 MAP_SHARED
| LTTNG_MAP_POPULATE
, shmfd
, 0);
158 if (memory_map
== MAP_FAILED
) {
162 obj
->type
= SHM_OBJECT_SHM
;
163 obj
->memory_map
= memory_map
;
164 obj
->memory_map_size
= memory_map_size
;
165 obj
->allocated_len
= 0;
166 obj
->index
= table
->allocated_len
++;
175 for (i
= 0; i
< 2; i
++) {
176 ret
= close(waitfd
[i
]);
187 struct shm_object
*_shm_object_table_alloc_mem(struct shm_object_table
*table
,
188 size_t memory_map_size
)
190 struct shm_object
*obj
;
192 int waitfd
[2], i
, ret
;
194 if (table
->allocated_len
>= table
->size
)
196 obj
= &table
->objects
[table
->allocated_len
];
198 memory_map
= zmalloc(memory_map_size
);
202 /* wait_fd: create pipe */
208 for (i
= 0; i
< 2; i
++) {
209 ret
= fcntl(waitfd
[i
], F_SETFD
, FD_CLOEXEC
);
215 /* The write end of the pipe needs to be non-blocking */
216 ret
= fcntl(waitfd
[1], F_SETFL
, O_NONBLOCK
);
221 memcpy(obj
->wait_fd
, waitfd
, sizeof(waitfd
));
225 obj
->shm_fd_ownership
= 0;
227 obj
->type
= SHM_OBJECT_MEM
;
228 obj
->memory_map
= memory_map
;
229 obj
->memory_map_size
= memory_map_size
;
230 obj
->allocated_len
= 0;
231 obj
->index
= table
->allocated_len
++;
236 for (i
= 0; i
< 2; i
++) {
237 ret
= close(waitfd
[i
]);
250 * libnuma prints errors on the console even for numa_available().
251 * Work-around this limitation by using get_mempolicy() directly to
252 * check whether the kernel supports mempolicy.
255 static bool lttng_is_numa_available(void)
259 ret
= get_mempolicy(NULL
, NULL
, 0, NULL
, 0);
260 if (ret
&& errno
== ENOSYS
) {
263 return numa_available() > 0;
267 struct shm_object
*shm_object_table_alloc(struct shm_object_table
*table
,
268 size_t memory_map_size
,
269 enum shm_object_type type
,
273 struct shm_object
*shm_object
;
275 int oldnode
= 0, node
;
278 numa_avail
= lttng_is_numa_available();
280 oldnode
= numa_preferred();
282 node
= numa_node_of_cpu(cpu
);
284 numa_set_preferred(node
);
286 if (cpu
< 0 || node
< 0)
287 numa_set_localalloc();
289 #endif /* HAVE_LIBNUMA */
292 shm_object
= _shm_object_table_alloc_shm(table
, memory_map_size
,
296 shm_object
= _shm_object_table_alloc_mem(table
, memory_map_size
);
303 numa_set_preferred(oldnode
);
304 #endif /* HAVE_LIBNUMA */
308 struct shm_object
*shm_object_table_append_shm(struct shm_object_table
*table
,
309 int shm_fd
, int wakeup_fd
, uint32_t stream_nr
,
310 size_t memory_map_size
)
312 struct shm_object
*obj
;
316 if (table
->allocated_len
>= table
->size
)
318 /* streams _must_ be received in sequential order, else fail. */
319 if (stream_nr
+ 1 != table
->allocated_len
)
322 obj
= &table
->objects
[table
->allocated_len
];
324 /* wait_fd: set write end of the pipe. */
325 obj
->wait_fd
[0] = -1; /* read end is unset */
326 obj
->wait_fd
[1] = wakeup_fd
;
327 obj
->shm_fd
= shm_fd
;
328 obj
->shm_fd_ownership
= 1;
330 /* The write end of the pipe needs to be non-blocking */
331 ret
= fcntl(obj
->wait_fd
[1], F_SETFL
, O_NONBLOCK
);
337 /* memory_map: mmap */
338 memory_map
= mmap(NULL
, memory_map_size
, PROT_READ
| PROT_WRITE
,
339 MAP_SHARED
| LTTNG_MAP_POPULATE
, shm_fd
, 0);
340 if (memory_map
== MAP_FAILED
) {
344 obj
->type
= SHM_OBJECT_SHM
;
345 obj
->memory_map
= memory_map
;
346 obj
->memory_map_size
= memory_map_size
;
347 obj
->allocated_len
= memory_map_size
;
348 obj
->index
= table
->allocated_len
++;
358 * Passing ownership of mem to object.
360 struct shm_object
*shm_object_table_append_mem(struct shm_object_table
*table
,
361 void *mem
, size_t memory_map_size
, int wakeup_fd
)
363 struct shm_object
*obj
;
366 if (table
->allocated_len
>= table
->size
)
368 obj
= &table
->objects
[table
->allocated_len
];
370 obj
->wait_fd
[0] = -1; /* read end is unset */
371 obj
->wait_fd
[1] = wakeup_fd
;
373 obj
->shm_fd_ownership
= 0;
375 ret
= fcntl(obj
->wait_fd
[1], F_SETFD
, FD_CLOEXEC
);
380 /* The write end of the pipe needs to be non-blocking */
381 ret
= fcntl(obj
->wait_fd
[1], F_SETFL
, O_NONBLOCK
);
387 obj
->type
= SHM_OBJECT_MEM
;
388 obj
->memory_map
= mem
;
389 obj
->memory_map_size
= memory_map_size
;
390 obj
->allocated_len
= memory_map_size
;
391 obj
->index
= table
->allocated_len
++;
400 void shmp_object_destroy(struct shm_object
*obj
, int consumer
)
407 ret
= munmap(obj
->memory_map
, obj
->memory_map_size
);
413 if (obj
->shm_fd_ownership
) {
414 /* Delete FDs only if called from app (not consumer). */
416 lttng_ust_lock_fd_tracker();
417 ret
= close(obj
->shm_fd
);
419 lttng_ust_delete_fd_from_tracker(obj
->shm_fd
);
424 lttng_ust_unlock_fd_tracker();
426 ret
= close(obj
->shm_fd
);
433 for (i
= 0; i
< 2; i
++) {
434 if (obj
->wait_fd
[i
] < 0)
437 lttng_ust_lock_fd_tracker();
438 ret
= close(obj
->wait_fd
[i
]);
440 lttng_ust_delete_fd_from_tracker(obj
->wait_fd
[i
]);
445 lttng_ust_unlock_fd_tracker();
447 ret
= close(obj
->wait_fd
[i
]);
460 for (i
= 0; i
< 2; i
++) {
461 if (obj
->wait_fd
[i
] < 0)
464 lttng_ust_lock_fd_tracker();
465 ret
= close(obj
->wait_fd
[i
]);
467 lttng_ust_delete_fd_from_tracker(obj
->wait_fd
[i
]);
472 lttng_ust_unlock_fd_tracker();
474 ret
= close(obj
->wait_fd
[i
]);
481 free(obj
->memory_map
);
489 void shm_object_table_destroy(struct shm_object_table
*table
, int consumer
)
493 for (i
= 0; i
< table
->allocated_len
; i
++)
494 shmp_object_destroy(&table
->objects
[i
], consumer
);
499 * zalloc_shm - allocate memory within a shm object.
501 * Shared memory is already zeroed by shmget.
502 * *NOT* multithread-safe (should be protected by mutex).
503 * Returns a -1, -1 tuple on error.
505 struct shm_ref
zalloc_shm(struct shm_object
*obj
, size_t len
)
508 struct shm_ref shm_ref_error
= { -1, -1 };
510 if (obj
->memory_map_size
- obj
->allocated_len
< len
)
511 return shm_ref_error
;
512 ref
.index
= obj
->index
;
513 ref
.offset
= obj
->allocated_len
;
514 obj
->allocated_len
+= len
;
518 void align_shm(struct shm_object
*obj
, size_t align
)
520 size_t offset_len
= lttng_ust_offset_align(obj
->allocated_len
, align
);
521 obj
->allocated_len
+= offset_len
;
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