--- /dev/null
+/*
+ * SPDX-License-Identifier: LGPL-2.1-only
+ *
+ * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#ifndef _LIBRINGBUFFER_SHM_H
+#define _LIBRINGBUFFER_SHM_H
+
+#include <stddef.h>
+#include <stdint.h>
+#include <unistd.h>
+#include "common/logging.h"
+#include <urcu/compiler.h>
+#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)
+ __attribute__((visibility("hidden")));
+
+/* 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)
+ __attribute__((visibility("hidden")));
+
+unsigned int channel_handle_get_nr_streams(struct lttng_ust_shm_handle *handle)
+ __attribute__((visibility("hidden")));
+
+/*
+ * 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)) _shmp_offset((handle)->table, &(ref)._ref, index, sizeof(*((ref)._type))))
+
+#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)
+ __attribute__((visibility("hidden")));
+
+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)
+ __attribute__((visibility("hidden")));
+
+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)
+ __attribute__((visibility("hidden")));
+
+/* 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)
+ __attribute__((visibility("hidden")));
+
+void shm_object_table_destroy(struct shm_object_table *table, int consumer)
+ __attribute__((visibility("hidden")));
+
+/*
+ * 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)
+ __attribute__((visibility("hidden")));
+
+void align_shm(struct shm_object *obj, size_t align)
+ __attribute__((visibility("hidden")));
+
+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 */
projects / lttng-ust.git / blobdiff