X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=libringbuffer%2Fbackend.h;h=2fe06cefd56f2c146b128762f9268c85101c5946;hb=aab8b172425eb52f2cd5bd71ce03f8a5624f83df;hp=52e632d86d247b0b9bf0ed79a472c06c4d6db006;hpb=b4051ad8c170901d5297e1b3005b24e63cb0ab1e;p=lttng-ust.git diff --git a/libringbuffer/backend.h b/libringbuffer/backend.h index 52e632d8..2fe06cef 100644 --- a/libringbuffer/backend.h +++ b/libringbuffer/backend.h @@ -1,31 +1,17 @@ -#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 * - * 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 #include @@ -37,10 +23,12 @@ /* 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); @@ -51,10 +39,13 @@ extern int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *b * 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, @@ -78,7 +69,7 @@ void lib_ring_buffer_write(const struct lttng_ust_lib_ring_buffer_config *config 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; @@ -146,10 +137,10 @@ size_t lib_ring_buffer_do_strcpy(const struct lttng_ust_lib_ring_buffer_config * 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; @@ -191,6 +182,64 @@ void lib_ring_buffer_strcpy(const struct lttng_ust_lib_ring_buffer_config *confi 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 @@ -205,7 +254,7 @@ unsigned long lib_ring_buffer_get_records_unread( 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)