dmesg: avoid mess at the end of dmesg output

Since util-linux commit a7ee94f2204011f26232ed3133514bf6e0d4a62c,
dmesg incorrectly calculates number of bytes that are remaining in the
buffer in get_next_record(). This could, under specific circumstances,
cause printing mess at the end of dmesg output:

> dmesg | tail
[ 1191.478725] Adding 285488k swap on /root/swapfile.  Priority:-2 extents:15 across:1186612k
[ 1205.588331] Adding 285488k swap on /root/swapfile.  Priority:-2 extents:15 across:1186612k
\xffffffba\xffffffba

Reported-by: Glenn Doig <doiggl@velocitynet.com.au>
Addresses: https://bugzilla.novell.com/show_bug.cgi?id=710417

Signed-off-by: Petr Uzel <petr.uzel@suse.cz>

diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
index 94f8c111d87ffc1c2314121194ed63f0d9605a2f..705269db0db7ed3bf32d2156620c66d775e5ff36 100644 (file)
--- a/sys-utils/dmesg.c
+++ b/sys-utils/dmesg.c
@@ -494,6 +494,8 @@ static int get_next_record(struct dmesg_control *ctl, struct dmesg_record *rec)
 
                rec->next_size -= end - rec->next;
                rec->next = rec->next_size > 0 ? end + 1 : NULL;
+               if (rec->next_size > 0)
+                       rec->next_size--;
 
                return 0;
        }