X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Fshm.h;h=e4a466e5a2f0853c12644885f1b20f39c380eb7e;hb=c0c0989ab70574e09b2f7e8b48c2da6af664a849;hp=390a5b26bc2890f996577ebbda3d0dc0303cb726;hpb=a6352fd40a2090fd883a6c369144bf405c9e9ec4;p=lttng-ust.git diff --git a/libringbuffer/shm.h b/libringbuffer/shm.h index 390a5b26..e4a466e5 100644 --- a/libringbuffer/shm.h +++ b/libringbuffer/shm.h @@ -1,71 +1,211 @@ +/* + * SPDX-License-Identifier: LGPL-2.1-only + * + * Copyright (C) 2011-2012 Mathieu Desnoyers + */ + #ifndef _LIBRINGBUFFER_SHM_H #define _LIBRINGBUFFER_SHM_H +#include +#include +#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); + /* - * libringbuffer/shm.h - * - * Copyright 2011 (c) - Mathieu Desnoyers + * Pointer dereferencing. We don't trust the shm_ref, so we validate + * both the index and offset with known boundaries. * - * Dual LGPL v2.1/GPL v2 license. + * "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; -#include -#include "ust/core.h" + 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 SHM_MAGIC 0x54335433 -#define SHM_MAJOR 0 -#define SHM_MINOR 1 +#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, + int cpu); +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, int consumer); /* - * Defining a max shm offset, for debugging purposes. + * 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. */ -#if (CAA_BITS_PER_LONG == 32) -/* Define the maximum shared memory size to 128MB on 32-bit machines */ -#define MAX_SHM_SIZE 134217728 -#else -/* Define the maximum shared memory size to 8GB on 64-bit machines */ -#define MAX_SHM_SIZE 8589934592 -#endif +struct shm_ref zalloc_shm(struct shm_object *obj, size_t len); +void align_shm(struct shm_object *obj, size_t align); -#define DECLARE_SHMP(type, name) type *****name +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; -struct shm_header { - uint32_t magic; - uint8_t major; - uint8_t minor; - uint8_t bits_per_long; - size_t shm_size, shm_allocated; + index = (size_t) ref->index; + if (caa_unlikely(index >= table->allocated_len)) + return -EPERM; + obj = &table->objects[index]; + return obj->wait_fd[0]; +} - DECLARE_SHMP(struct channel, chan); -}; +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; -#define shmp(shm_offset) \ - ((__typeof__(****(shm_offset))) (((char *) &(shm_offset)) + (ptrdiff_t) (shm_offset))) + index = (size_t) ref->index; + if (caa_unlikely(index >= table->allocated_len)) + return -EPERM; + obj = &table->objects[index]; + return obj->wait_fd[1]; +} -#define _shmp_abs(a) ((a < 0) ? -(a) : (a)) +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 -void _set_shmp(ptrdiff_t *shm_offset, void *ptr) +int shm_close_wakeup_fd(struct lttng_ust_shm_handle *handle, + struct shm_ref *ref) { - *shm_offset = (((char *) ptr) - ((char *) shm_offset)); - assert(_shmp_abs(*shm_offset) < MAX_SHM_SIZE); + 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; } -#define set_shmp(shm_offset, ptr) \ - _set_shmp((ptrdiff_t *) ****(shm_offset), ptr) -/* Shared memory is already zeroed by shmget */ -/* *NOT* multithread-safe (should be protected by mutex) */ static inline -void *zalloc_shm(struct shm_header *shm_header, size_t len) +int shm_get_shm_size(struct lttng_ust_shm_handle *handle, struct shm_ref *ref, + uint64_t *size) { - void *ret; + struct shm_object_table *table = handle->table; + struct shm_object *obj; + size_t index; - if (shm_header->shm_size - shm_header->shm_allocated < len) - return NULL; - ret = (char *) shm_header + shm_header->shm_allocated; - shm_header->shm_allocated += len; - return ret; + 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 */