X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=libringbuffer%2Fring_buffer_backend.c;h=02c893d3d796544ad9722baf9246b391010831aa;hb=refs%2Fheads%2Fstable-2.0;hp=9b33408125e96c80981fa3f9bacdd54f716e0efb;hpb=96e80018cb6ef2098193bd4d8fe724df29f2faf0;p=lttng-ust.git

diff --git a/libringbuffer/ring_buffer_backend.c b/libringbuffer/ring_buffer_backend.c
index 9b334081..02c893d3 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 <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
@@ -210,18 +222,18 @@ 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;
 
 	ret = subbuffer_id_check_index(config, num_subbuf);
 	if (ret)
@@ -367,8 +379,9 @@ 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 +393,8 @@ 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;