1 #ifndef _LIBCOUNTER_SHM_H
2 #define _LIBCOUNTER_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 /* lttng_counter_handle_create - for UST. */
33 struct lttng_counter_shm_handle
*lttng_counter_handle_create(void *data
,
34 uint64_t memory_map_size
, int wakeup_fd
);
35 /* lttng_counter_handle_add_cpu - for UST. */
37 int lttng_counter_handle_add_cpu(struct lttng_counter_shm_handle
*handle
,
38 int shm_fd
, uint32_t cpu_nr
,
39 uint64_t memory_map_size
);
40 unsigned int lttng_counter_handle_get_nr_cpus(struct lttng_counter_shm_handle
*handle
);
43 * Pointer dereferencing. We don't trust the shm_ref, so we validate
44 * both the index and offset with known boundaries.
46 * "shmp" and "shmp_index" guarantee that it's safe to use the pointer
47 * target type, even in the occurrence of shm_ref modification by an
48 * untrusted process having write access to the shm_ref. We return a
49 * NULL pointer if the ranges are invalid.
52 char *_lttng_counter_shmp_offset(struct lttng_counter_shm_object_table
*table
,
53 struct lttng_counter_shm_ref
*ref
,
54 size_t idx
, size_t elem_size
)
56 struct lttng_counter_shm_object
*obj
;
57 size_t objindex
, ref_offset
;
59 objindex
= (size_t) ref
->index
;
60 if (caa_unlikely(objindex
>= table
->allocated_len
))
62 obj
= &table
->objects
[objindex
];
63 ref_offset
= (size_t) ref
->offset
;
64 ref_offset
+= idx
* elem_size
;
65 /* Check if part of the element returned would exceed the limits. */
66 if (caa_unlikely(ref_offset
+ elem_size
> obj
->memory_map_size
))
68 return &obj
->memory_map
[ref_offset
];
71 #define lttng_counter_shmp_index(handle, ref, index) \
73 __typeof__((ref)._type) ____ptr_ret; \
74 ____ptr_ret = (__typeof__(____ptr_ret)) _lttng_counter_shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \
78 #define lttng_counter_shmp(handle, ref) lttng_counter_shmp_index(handle, ref, 0)
81 void _lttng_counter_set_shmp(struct lttng_counter_shm_ref
*ref
, struct lttng_counter_shm_ref src
)
86 #define lttng_counter_set_shmp(ref, src) _lttng_counter_set_shmp(&(ref)._ref, src)
88 struct lttng_counter_shm_object_table
*lttng_counter_shm_object_table_create(size_t max_nb_obj
);
89 struct lttng_counter_shm_object
*lttng_counter_shm_object_table_alloc(struct lttng_counter_shm_object_table
*table
,
90 size_t memory_map_size
,
91 enum lttng_counter_shm_object_type type
,
94 struct lttng_counter_shm_object
*lttng_counter_shm_object_table_append_shm(struct lttng_counter_shm_object_table
*table
,
95 int shm_fd
, size_t memory_map_size
);
96 /* mem ownership is passed to lttng_counter_shm_object_table_append_mem(). */
97 struct lttng_counter_shm_object
*lttng_counter_shm_object_table_append_mem(struct lttng_counter_shm_object_table
*table
,
98 void *mem
, size_t memory_map_size
);
99 void lttng_counter_shm_object_table_destroy(struct lttng_counter_shm_object_table
*table
, int consumer
);
102 * lttng_counter_zalloc_shm - allocate memory within a shm object.
104 * Shared memory is already zeroed by shmget.
105 * *NOT* multithread-safe (should be protected by mutex).
106 * Returns a -1, -1 tuple on error.
108 struct lttng_counter_shm_ref
lttng_counter_zalloc_shm(struct lttng_counter_shm_object
*obj
, size_t len
);
109 void lttng_counter_align_shm(struct lttng_counter_shm_object
*obj
, size_t align
);
112 int lttng_counter_shm_get_shm_fd(struct lttng_counter_shm_handle
*handle
, struct lttng_counter_shm_ref
*ref
)
114 struct lttng_counter_shm_object_table
*table
= handle
->table
;
115 struct lttng_counter_shm_object
*obj
;
118 index
= (size_t) ref
->index
;
119 if (caa_unlikely(index
>= table
->allocated_len
))
121 obj
= &table
->objects
[index
];
127 int lttng_counter_shm_get_shm_size(struct lttng_counter_shm_handle
*handle
, struct lttng_counter_shm_ref
*ref
,
130 struct lttng_counter_shm_object_table
*table
= handle
->table
;
131 struct lttng_counter_shm_object
*obj
;
134 index
= (size_t) ref
->index
;
135 if (caa_unlikely(index
>= table
->allocated_len
))
137 obj
= &table
->objects
[index
];
138 *size
= obj
->memory_map_size
;
142 #endif /* _LIBCOUNTER_SHM_H */