X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=libcounter%2Fshm.h;fp=libcounter%2Fshm.h;h=2c6e0c7b15177d46685a87a5278323a97e69406b;hb=ebabbf580131acd1fe246c4d31fc5c044d36a038;hp=0000000000000000000000000000000000000000;hpb=d37ecb3fc622dee6f80f84c21f38d32eef407262;p=deliverable%2Flttng-ust.git diff --git a/libcounter/shm.h b/libcounter/shm.h new file mode 100644 index 00000000..2c6e0c7b --- /dev/null +++ b/libcounter/shm.h @@ -0,0 +1,142 @@ +#ifndef _LIBCOUNTER_SHM_H +#define _LIBCOUNTER_SHM_H + +/* + * libcounter/shm.h + * + * Copyright (C) 2011-2012 Mathieu Desnoyers + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; only + * version 2.1 of the License. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include +#include +#include +#include +#include +#include "shm_types.h" + +/* lttng_counter_handle_create - for UST. */ +extern +struct lttng_counter_shm_handle *lttng_counter_handle_create(void *data, + uint64_t memory_map_size, int wakeup_fd); +/* lttng_counter_handle_add_cpu - for UST. */ +extern +int lttng_counter_handle_add_cpu(struct lttng_counter_shm_handle *handle, + int shm_fd, uint32_t cpu_nr, + uint64_t memory_map_size); +unsigned int lttng_counter_handle_get_nr_cpus(struct lttng_counter_shm_handle *handle); + +/* + * Pointer dereferencing. We don't trust the shm_ref, so we validate + * both the index and offset with known boundaries. + * + * "shmp" and "shmp_index" guarantee that it's safe to use the pointer + * target type, even in the occurrence of shm_ref modification by an + * untrusted process having write access to the shm_ref. We return a + * NULL pointer if the ranges are invalid. + */ +static inline +char *_lttng_counter_shmp_offset(struct lttng_counter_shm_object_table *table, + struct lttng_counter_shm_ref *ref, + size_t idx, size_t elem_size) +{ + struct lttng_counter_shm_object *obj; + size_t objindex, ref_offset; + + objindex = (size_t) ref->index; + if (caa_unlikely(objindex >= table->allocated_len)) + return NULL; + obj = &table->objects[objindex]; + ref_offset = (size_t) ref->offset; + ref_offset += idx * elem_size; + /* Check if part of the element returned would exceed the limits. */ + if (caa_unlikely(ref_offset + elem_size > obj->memory_map_size)) + return NULL; + return &obj->memory_map[ref_offset]; +} + +#define lttng_counter_shmp_index(handle, ref, index) \ + ({ \ + __typeof__((ref)._type) ____ptr_ret; \ + ____ptr_ret = (__typeof__(____ptr_ret)) _lttng_counter_shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \ + ____ptr_ret; \ + }) + +#define lttng_counter_shmp(handle, ref) lttng_counter_shmp_index(handle, ref, 0) + +static inline +void _lttng_counter_set_shmp(struct lttng_counter_shm_ref *ref, struct lttng_counter_shm_ref src) +{ + *ref = src; +} + +#define lttng_counter_set_shmp(ref, src) _lttng_counter_set_shmp(&(ref)._ref, src) + +struct lttng_counter_shm_object_table *lttng_counter_shm_object_table_create(size_t max_nb_obj); +struct lttng_counter_shm_object *lttng_counter_shm_object_table_alloc(struct lttng_counter_shm_object_table *table, + size_t memory_map_size, + enum lttng_counter_shm_object_type type, + const int cpu_fd, + int cpu); +struct lttng_counter_shm_object *lttng_counter_shm_object_table_append_shm(struct lttng_counter_shm_object_table *table, + int shm_fd, size_t memory_map_size); +/* mem ownership is passed to lttng_counter_shm_object_table_append_mem(). */ +struct lttng_counter_shm_object *lttng_counter_shm_object_table_append_mem(struct lttng_counter_shm_object_table *table, + void *mem, size_t memory_map_size); +void lttng_counter_shm_object_table_destroy(struct lttng_counter_shm_object_table *table, int consumer); + +/* + * lttng_counter_zalloc_shm - allocate memory within a shm object. + * + * Shared memory is already zeroed by shmget. + * *NOT* multithread-safe (should be protected by mutex). + * Returns a -1, -1 tuple on error. + */ +struct lttng_counter_shm_ref lttng_counter_zalloc_shm(struct lttng_counter_shm_object *obj, size_t len); +void lttng_counter_align_shm(struct lttng_counter_shm_object *obj, size_t align); + +static inline +int lttng_counter_shm_get_shm_fd(struct lttng_counter_shm_handle *handle, struct lttng_counter_shm_ref *ref) +{ + struct lttng_counter_shm_object_table *table = handle->table; + struct lttng_counter_shm_object *obj; + size_t index; + + index = (size_t) ref->index; + if (caa_unlikely(index >= table->allocated_len)) + return -EPERM; + obj = &table->objects[index]; + return obj->shm_fd; +} + + +static inline +int lttng_counter_shm_get_shm_size(struct lttng_counter_shm_handle *handle, struct lttng_counter_shm_ref *ref, + uint64_t *size) +{ + struct lttng_counter_shm_object_table *table = handle->table; + struct lttng_counter_shm_object *obj; + size_t index; + + index = (size_t) ref->index; + if (caa_unlikely(index >= table->allocated_len)) + return -EPERM; + obj = &table->objects[index]; + *size = obj->memory_map_size; + return 0; +} + +#endif /* _LIBCOUNTER_SHM_H */