X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=libringbuffer%2Fring_buffer_backend.c;h=6d2d9507bec59edfe56658a0c8e10efffaf8d132;hb=8ed89704969af8ce7758224fffc73b74ee0ab470;hp=4bc4b767f0679d5fee431fc6143df567cd6a0c9c;hpb=b124e2ec1b9064cdfb82dfa14a5d67ff2e7146c6;p=lttng-ust.git diff --git a/libringbuffer/ring_buffer_backend.c b/libringbuffer/ring_buffer_backend.c index 4bc4b767..6d2d9507 100644 --- a/libringbuffer/ring_buffer_backend.c +++ b/libringbuffer/ring_buffer_backend.c @@ -1,12 +1,25 @@ /* * ring_buffer_backend.c * - * Copyright (C) 2005-2010 - Mathieu Desnoyers + * Copyright (C) 2005-2012 Mathieu Desnoyers * - * 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 #include #include @@ -37,6 +50,7 @@ int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_conf 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; @@ -44,6 +58,11 @@ int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_conf 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)); @@ -52,9 +71,9 @@ int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_conf /* * 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))) @@ -111,6 +130,7 @@ free_array: memory_map_error: /* bufb->array will be freed by shm teardown */ array_error: +page_size_error: return -ENOMEM; } @@ -184,7 +204,7 @@ void channel_backend_reset(struct channel_backend *chanb) * @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 * @@ -206,12 +226,17 @@ int channel_backend_init(struct channel_backend *chanb, 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; /* @@ -222,6 +247,12 @@ int channel_backend_init(struct channel_backend *chanb, 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) @@ -248,7 +279,7 @@ int channel_backend_init(struct channel_backend *chanb, 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; @@ -268,7 +299,8 @@ int channel_backend_init(struct channel_backend *chanb, 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)); @@ -286,7 +318,8 @@ int channel_backend_init(struct channel_backend *chanb, 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)); @@ -367,8 +400,9 @@ size_t lib_ring_buffer_read(struct lttng_ust_lib_ring_buffer_backend *bufb, size * @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) @@ -380,6 +414,8 @@ int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb, si 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; @@ -408,8 +444,9 @@ int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb, si * * 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,