X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Fring_buffer_backend.c;h=7d3a37809e73da27b25d43d8914ed285545075f7;hb=3d8e9399b2fb9000b3b55e488a7d04184b5bb56e;hp=dead69600f7a06391d9b276e348820eb0a59208a;hpb=cb14bae9a1eed58f0c07f2529e2a5dfa931dd10c;p=lttng-ust.git

diff --git a/libringbuffer/ring_buffer_backend.c b/libringbuffer/ring_buffer_backend.c
index dead6960..7d3a3780 100644
--- a/libringbuffer/ring_buffer_backend.c
+++ b/libringbuffer/ring_buffer_backend.c
@@ -1,12 +1,26 @@
 /*
  * 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 <urcu/arch.h>
+#include <limits.h>
 
 #include <lttng/ringbuffer-config.h>
 #include "vatomic.h"
@@ -208,18 +222,24 @@ int channel_backend_init(struct channel_backend *chanb,
 	if (!name)
 		return -EPERM;
 
-	if (!(subbuf_size && num_subbuf))
-		return -EPERM;
-
 	/* Check that the subbuffer size is larger than a page. */
 	if (subbuf_size < PAGE_SIZE)
 		return -EINVAL;
 
 	/*
-	 * Make sure the number of subbuffers and subbuffer size are power of 2.
+	 * Make sure the number of subbuffers and subbuffer size are
+	 * power of 2, and nonzero.
 	 */
-	CHAN_WARN_ON(chanb, hweight32(subbuf_size) != 1);
-	CHAN_WARN_ON(chanb, hweight32(num_subbuf) != 1);
+	if (!subbuf_size || (subbuf_size & (subbuf_size - 1)))
+		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)
@@ -266,7 +286,8 @@ 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));
@@ -284,7 +305,8 @@ 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));
@@ -365,8 +387,9 @@ 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)
@@ -378,6 +401,8 @@ 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;
@@ -406,8 +431,9 @@ 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,