/*
* ring_buffer_backend.c
*
- * Copyright (C) 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
- * Dual LGPL v2.1/GPL v2 license.
+ * 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
*/
#define _GNU_SOURCE
+#include <unistd.h>
#include <urcu/arch.h>
#include <limits.h>
unsigned long subbuf_size, mmap_offset = 0;
unsigned long num_subbuf_alloc;
unsigned long i;
+ long page_size;
subbuf_size = chanb->subbuf_size;
num_subbuf_alloc = num_subbuf;
if (extra_reader_sb)
num_subbuf_alloc++;
+ page_size = sysconf(_SC_PAGE_SIZE);
+ if (page_size <= 0) {
+ goto page_size_error;
+ }
+
align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp));
set_shmp(bufb->array, zalloc_shm(shmobj,
sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc));
/*
* This is the largest element (the buffer pages) which needs to
- * be aligned on PAGE_SIZE.
+ * be aligned on page size.
*/
- align_shm(shmobj, PAGE_SIZE);
+ align_shm(shmobj, page_size);
set_shmp(bufb->memory_map, zalloc_shm(shmobj,
subbuf_size * num_subbuf_alloc));
if (caa_unlikely(!shmp(handle, bufb->memory_map)))
memory_map_error:
/* bufb->array will be freed by shm teardown */
array_error:
+page_size_error:
return -ENOMEM;
}
* @name: channel name
* @config: client ring buffer configuration
* @parent: dentry of parent directory, %NULL for root directory
- * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2)
+ * @subbuf_size: size of sub-buffers (> page size, power of 2)
* @num_subbuf: number of sub-buffers (power of 2)
* @lttng_ust_shm_handle: shared memory handle
*
unsigned int i;
int ret;
size_t shmsize = 0, num_subbuf_alloc;
+ long page_size;
if (!name)
return -EPERM;
+ page_size = sysconf(_SC_PAGE_SIZE);
+ if (page_size <= 0) {
+ return -ENOMEM;
+ }
/* Check that the subbuffer size is larger than a page. */
- if (subbuf_size < PAGE_SIZE)
+ if (subbuf_size < page_size)
return -EINVAL;
/*
return -EINVAL;
if (!num_subbuf || (num_subbuf & (num_subbuf - 1)))
return -EINVAL;
+ /*
+ * Overwrite mode buffers require at least 2 subbuffers per
+ * buffer.
+ */
+ if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2)
+ return -EINVAL;
ret = subbuffer_id_check_index(config, num_subbuf);
if (ret)
num_subbuf_alloc = num_subbuf + 1;
shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp));
shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc;
- shmsize += offset_align(shmsize, PAGE_SIZE);
+ shmsize += offset_align(shmsize, page_size);
shmsize += subbuf_size * num_subbuf_alloc;
shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages));
shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages) * num_subbuf_alloc;
for_each_possible_cpu(i) {
struct shm_object *shmobj;
- shmobj = shm_object_table_append(handle->table, shmsize);
+ shmobj = shm_object_table_alloc(handle->table, shmsize,
+ SHM_OBJECT_SHM);
if (!shmobj)
goto end;
align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer));
struct shm_object *shmobj;
struct lttng_ust_lib_ring_buffer *buf;
- shmobj = shm_object_table_append(handle->table, shmsize);
+ shmobj = shm_object_table_alloc(handle->table, shmsize,
+ SHM_OBJECT_SHM);
if (!shmobj)
goto end;
align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer));
* @dest : destination address
* @len : destination's length
*
- * return string's length
+ * Return string's length, or -EINVAL on error.
* Should be protected by get_subbuf/put_subbuf.
+ * Destination length should be at least 1 to hold '\0'.
*/
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)
struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages;
unsigned long sb_bindex, id;
+ if (caa_unlikely(!len))
+ return -EINVAL;
offset &= chanb->buf_size - 1;
orig_offset = offset;
id = bufb->buf_rsb.id;
*
* Return the address where a given offset is located (for read).
* Should be used to get the current subbuffer header pointer. Given we know
- * 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.
+ * it's never on a page boundary, it's safe to read/write directly
+ * from/to this address, as long as the read/write is never bigger than
+ * a page size.
*/
void *lib_ring_buffer_read_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb,
size_t offset,
projects / lttng-ust.git / blobdiff