-#ifndef _LTTNG_RING_BUFFER_BACKEND_H
-#define _LTTNG_RING_BUFFER_BACKEND_H
-
/*
- * libringbuffer/backend.h
- *
- * Ring buffer backend (API).
+ * SPDX-License-Identifier: LGPL-2.1-only
*
* Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
- * 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
+ * Ring buffer backend (API).
*
* Credits to Steven Rostedt for proposing to use an extra-subbuffer owned by
* the reader in flight recorder mode.
*/
+#ifndef _LTTNG_RING_BUFFER_BACKEND_H
+#define _LTTNG_RING_BUFFER_BACKEND_H
+
+#include <stddef.h>
#include <unistd.h>
/* Internal helpers */
/* Ring buffer backend access (read/write) */
+__attribute__((visibility("hidden")))
extern size_t lib_ring_buffer_read(struct lttng_ust_lib_ring_buffer_backend *bufb,
size_t offset, void *dest, size_t len,
struct lttng_ust_shm_handle *handle);
+__attribute__((visibility("hidden")))
extern int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb,
size_t offset, void *dest, size_t len,
struct lttng_ust_shm_handle *handle);
* it's never on a page boundary, it's safe to write directly to this address,
* as long as the write is never bigger than a page size.
*/
+__attribute__((visibility("hidden")))
extern void *
lib_ring_buffer_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb,
size_t offset,
struct lttng_ust_shm_handle *handle);
+
+__attribute__((visibility("hidden")))
extern void *
lib_ring_buffer_read_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb,
size_t offset,
* backend-specific memcpy() operation. Calls the slow path (_ring_buffer_write)
* if copy is crossing a page boundary.
*/
-static inline
+static inline __attribute__((always_inline))
void lib_ring_buffer_write(const struct lttng_ust_lib_ring_buffer_config *config,
struct lttng_ust_lib_ring_buffer_ctx *ctx,
const void *src, size_t len)
{
struct channel_backend *chanb = &ctx->chan->backend;
- struct lttng_ust_shm_handle *handle = ctx->handle;
+ struct lttng_ust_shm_handle *handle = ctx->chan->handle;
size_t offset = ctx->buf_offset;
struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
void *p;
* terminating character is found in @src. Returns the number of bytes
* copied. Does *not* terminate @dest with NULL terminating character.
*/
-static inline
+static inline __attribute__((always_inline))
size_t lib_ring_buffer_do_strcpy(const struct lttng_ust_lib_ring_buffer_config *config,
char *dest, const char *src, size_t len)
{
* character is found in @src before @len - 1 characters are copied, pad
* the buffer with @pad characters (e.g. '#').
*/
-static inline
+static inline __attribute__((always_inline))
void lib_ring_buffer_strcpy(const struct lttng_ust_lib_ring_buffer_config *config,
struct lttng_ust_lib_ring_buffer_ctx *ctx,
- const char *src, size_t len, int pad)
+ const char *src, size_t len, char pad)
{
struct channel_backend *chanb = &ctx->chan->backend;
- struct lttng_ust_shm_handle *handle = ctx->handle;
+ struct lttng_ust_shm_handle *handle = ctx->chan->handle;
size_t count;
size_t offset = ctx->buf_offset;
struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
ctx->buf_offset += len;
}
+/**
+ * lib_ring_buffer_pstrcpy - write to a buffer backend P-string
+ * @config : ring buffer instance configuration
+ * @ctx: ring buffer context. (input arguments only)
+ * @src : source pointer to copy from
+ * @len : length of data to copy
+ * @pad : character to use for padding
+ *
+ * This function copies up to @len bytes of data from a source pointer
+ * to a Pascal String into the buffer backend. If a terminating '\0'
+ * character is found in @src before @len characters are copied, pad the
+ * buffer with @pad characters (e.g. '\0').
+ *
+ * The length of the pascal strings in the ring buffer is explicit: it
+ * is either the array or sequence length.
+ */
+static inline __attribute__((always_inline))
+void lib_ring_buffer_pstrcpy(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer_ctx *ctx,
+ const char *src, size_t len, char pad)
+{
+ struct channel_backend *chanb = &ctx->chan->backend;
+ struct lttng_ust_shm_handle *handle = ctx->chan->handle;
+ size_t count;
+ size_t offset = ctx->buf_offset;
+ struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
+ void *p;
+
+ if (caa_unlikely(!len))
+ return;
+ /*
+ * Underlying layer should never ask for writes across
+ * subbuffers.
+ */
+ CHAN_WARN_ON(chanb, (offset & (chanb->buf_size - 1)) + len > chanb->buf_size);
+ backend_pages = lib_ring_buffer_get_backend_pages_from_ctx(config, ctx);
+ if (caa_unlikely(!backend_pages)) {
+ if (lib_ring_buffer_backend_get_pages(config, ctx, &backend_pages))
+ return;
+ }
+ p = shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1));
+ if (caa_unlikely(!p))
+ return;
+
+ count = lib_ring_buffer_do_strcpy(config, p, src, len);
+ offset += count;
+ /* Padding */
+ if (caa_unlikely(count < len)) {
+ size_t pad_len = len - count;
+
+ p = shmp_index(handle, backend_pages->p, offset & (chanb->subbuf_size - 1));
+ if (caa_unlikely(!p))
+ return;
+ lib_ring_buffer_do_memset(p, pad, pad_len);
+ }
+ ctx->buf_offset += len;
+}
+
/*
* This accessor counts the number of unread records in a buffer.
* It only provides a consistent value if no reads not writes are performed
struct lttng_ust_lib_ring_buffer_backend *bufb = &buf->backend;
unsigned long records_unread = 0, sb_bindex;
unsigned int i;
- struct channel *chan;
+ struct lttng_ust_lib_ring_buffer_channel *chan;
chan = shmp(handle, bufb->chan);
if (!chan)
projects / lttng-ust.git / blobdiff