X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=libringbuffer%2Fring_buffer_backend.c;h=3a667adce53c8ccdda4f15b872c13d054907f7ed;hb=a9ff648cc;hp=4bc4b767f0679d5fee431fc6143df567cd6a0c9c;hpb=b124e2ec1b9064cdfb82dfa14a5d67ff2e7146c6;p=lttng-ust.git diff --git a/libringbuffer/ring_buffer_backend.c b/libringbuffer/ring_buffer_backend.c index 4bc4b767..3a667adc 100644 --- a/libringbuffer/ring_buffer_backend.c +++ b/libringbuffer/ring_buffer_backend.c @@ -1,9 +1,21 @@ /* * 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 @@ -17,6 +29,8 @@ #include "smp.h" #include "shm.h" +#define UINT_MAX_STR_LEN 11 /* includes \0 */ + /** * lib_ring_buffer_backend_allocate - allocate a channel buffer * @config: ring buffer instance configuration @@ -103,7 +117,6 @@ int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_conf mmap_offset += subbuf_size; } } - return 0; free_array: @@ -187,6 +200,7 @@ void channel_backend_reset(struct channel_backend *chanb) * @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 + * @shm_path: shared memory files path * * Returns channel pointer if successful, %NULL otherwise. * @@ -200,7 +214,8 @@ int channel_backend_init(struct channel_backend *chanb, const char *name, const struct lttng_ust_lib_ring_buffer_config *config, size_t subbuf_size, size_t num_subbuf, - struct lttng_ust_shm_handle *handle) + struct lttng_ust_shm_handle *handle, + const char *shm_path) { struct channel *chan = caa_container_of(chanb, struct channel, backend); unsigned int i; @@ -222,6 +237,12 @@ 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) @@ -267,8 +288,21 @@ 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); + char shm_buf_path[PATH_MAX]; + + if (shm_path) { + char cpu_nr[UINT_MAX_STR_LEN]; /* unsigned int max len */ + + strncpy(shm_buf_path, shm_path, PATH_MAX); + shm_buf_path[PATH_MAX - 1] = '\0'; + ret = snprintf(cpu_nr, UINT_MAX_STR_LEN, "%u", i); + if (ret != 1) + goto end; + strncat(shm_buf_path, cpu_nr, + PATH_MAX - strlen(shm_buf_path) - 1); + } + shmobj = shm_object_table_alloc(handle->table, shmsize, + SHM_OBJECT_SHM, shm_path ? shm_buf_path : NULL); if (!shmobj) goto end; align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); @@ -286,7 +320,8 @@ 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, shm_path); if (!shmobj) goto end; align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer)); @@ -367,8 +402,9 @@ 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 +416,8 @@ 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 +446,9 @@ 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,