#ifndef _LIBRINGBUFFER_SHM_H #define _LIBRINGBUFFER_SHM_H /* * libringbuffer/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 "shm_types.h" /* channel_handle_create - for UST. */ extern struct lttng_ust_shm_handle *channel_handle_create(void *data, uint64_t memory_map_size, int wakeup_fd); /* channel_handle_add_stream - for UST. */ extern int channel_handle_add_stream(struct lttng_ust_shm_handle *handle, int shm_fd, int wakeup_fd, uint32_t stream_nr, uint64_t memory_map_size); unsigned int channel_handle_get_nr_streams(struct lttng_ust_shm_handle *handle); extern void channel_destroy(struct channel *chan, struct lttng_ust_shm_handle *handle, int consumer); /* * 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 *_shmp_offset(struct shm_object_table *table, struct shm_ref *ref, size_t idx, size_t elem_size) { struct 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 shmp_index(handle, ref, index) \ ({ \ __typeof__((ref)._type) ____ptr_ret; \ ____ptr_ret = (__typeof__(____ptr_ret)) _shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*____ptr_ret)); \ ____ptr_ret; \ }) #define shmp(handle, ref) shmp_index(handle, ref, 0) static inline void _set_shmp(struct shm_ref *ref, struct shm_ref src) { *ref = src; } #define set_shmp(ref, src) _set_shmp(&(ref)._ref, src) struct shm_object_table *shm_object_table_create(size_t max_nb_obj); struct shm_object *shm_object_table_alloc(struct shm_object_table *table, size_t memory_map_size, enum shm_object_type type, const int stream_fd); struct shm_object *shm_object_table_append_shm(struct shm_object_table *table, int shm_fd, int wakeup_fd, uint32_t stream_nr, size_t memory_map_size); /* mem ownership is passed to shm_object_table_append_mem(). */ struct shm_object *shm_object_table_append_mem(struct shm_object_table *table, void *mem, size_t memory_map_size, int wakeup_fd); void shm_object_table_destroy(struct shm_object_table *table); /* * 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 shm_ref zalloc_shm(struct shm_object *obj, size_t len); void align_shm(struct shm_object *obj, size_t align); static inline int shm_get_wait_fd(struct lttng_ust_shm_handle *handle, struct shm_ref *ref) { struct shm_object_table *table = handle->table; struct 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->wait_fd[0]; } static inline int shm_get_wakeup_fd(struct lttng_ust_shm_handle *handle, struct shm_ref *ref) { struct shm_object_table *table = handle->table; struct 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->wait_fd[1]; } static inline int shm_close_wait_fd(struct lttng_ust_shm_handle *handle, struct shm_ref *ref) { struct shm_object_table *table = handle->table; struct shm_object *obj; int wait_fd; size_t index; int ret; index = (size_t) ref->index; if (caa_unlikely(index >= table->allocated_len)) return -EPERM; obj = &table->objects[index]; wait_fd = obj->wait_fd[0]; if (wait_fd < 0) return -ENOENT; obj->wait_fd[0] = -1; ret = close(wait_fd); if (ret) { ret = -errno; return ret; } return 0; } static inline int shm_close_wakeup_fd(struct lttng_ust_shm_handle *handle, struct shm_ref *ref) { struct shm_object_table *table = handle->table; struct shm_object *obj; int wakeup_fd; size_t index; int ret; index = (size_t) ref->index; if (caa_unlikely(index >= table->allocated_len)) return -EPERM; obj = &table->objects[index]; wakeup_fd = obj->wait_fd[1]; if (wakeup_fd < 0) return -ENOENT; obj->wait_fd[1] = -1; ret = close(wakeup_fd); if (ret) { ret = -errno; return ret; } return 0; } static inline int shm_get_shm_fd(struct lttng_ust_shm_handle *handle, struct shm_ref *ref) { struct shm_object_table *table = handle->table; struct 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 shm_get_shm_size(struct lttng_ust_shm_handle *handle, struct shm_ref *ref, uint64_t *size) { struct shm_object_table *table = handle->table; struct 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 /* _LIBRINGBUFFER_SHM_H */