[PATCH 0/2] Strict aliasing

[PATCH 0/2] Strict aliasing

[Zdenek Kabelac]

Patch goes with test that executes partition scanning code path
(so improves our coverage a bit)

Looks like are command line --config options has some room
for improvements as I had to change the global config.


Zdenek Kabelac (2):
  Fix compiler warning about strict-aliasing break
  Testcase for partition table scanning

 lib/device/device.c      |   18 +++++++++---------
 test/t-test-partition.sh |   30 ++++++++++++++++++++++++++++++
 test/test-utils.sh       |    1 +
 3 files changed, 40 insertions(+), 9 deletions(-)
 create mode 100755 test/t-test-partition.sh

-- 
1.7.3.1

[PATCH 1/2] Fix compiler warning about strict-aliasing break

[Zdenek Kabelac]

This patch not really tested - and just show a possible solution
for strict-alliasing error.

So patch is just a proposal of one of many solution.

Signed-off-by: Zdenek Kabelac <zkabelac@redhat.com>
---
 lib/device/device.c |   18 +++++++++---------
 1 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/lib/device/device.c b/lib/device/device.c
index 593e642..91eb14c 100644
--- a/lib/device/device.c
+++ b/lib/device/device.c
@@ -58,9 +58,11 @@ static int _has_partition_table(struct device *dev)
 {
 	int ret = 0;
 	unsigned p;
-	uint16_t buf[SECTOR_SIZE/sizeof(uint16_t)];
-	uint16_t *part_magic;
-	struct partition *part;
+	struct {
+		uint8_t skip[PART_OFFSET];
+		struct partition part[4];
+		uint16_t magic;
+	} __attribute__((packed)) buf; /* sizeof() == SECTOR_SIZE */
 
 	if (!dev_read(dev, UINT64_C(0), sizeof(buf), &buf))
 		return_0;
@@ -68,17 +70,15 @@ static int _has_partition_table(struct device *dev)
 	/* FIXME Check for other types of partition table too */
 
 	/* Check for msdos partition table */
-	part_magic = buf + PART_MAGIC_OFFSET/sizeof(buf[0]);
-	if ((*part_magic == xlate16(PART_MAGIC))) {
-		part = (struct partition *) (buf + PART_OFFSET/sizeof(buf[0]));
-		for (p = 0; p < 4; p++, part++) {
+	if (buf.magic == xlate16(PART_MAGIC)) {
+		for (p = 0; p < 4; ++p) {
 			/* Table is invalid if boot indicator not 0 or 0x80 */
-			if ((part->boot_ind & 0x7f)) {
+			if (buf.part[p].boot_ind & 0x7f) {
 				ret = 0;
 				break;
 			}
 			/* Must have at least one non-empty partition */
-			if (part->nr_sects)
+			if (buf.part[p].nr_sects)
 				ret = 1;
 		}
 	}
-- 
1.7.3.1

[PATCH 2/2] Testcase for partition table scanning

[Zdenek Kabelac]

Signed-off-by: Zdenek Kabelac <zkabelac@redhat.com>
---
 test/t-test-partition.sh |   30 ++++++++++++++++++++++++++++++
 test/test-utils.sh       |    1 +
 2 files changed, 31 insertions(+), 0 deletions(-)
 create mode 100755 test/t-test-partition.sh

diff --git a/test/t-test-partition.sh b/test/t-test-partition.sh
new file mode 100755
index 0000000..45a0aba
--- /dev/null
+++ b/test/t-test-partition.sh
@@ -0,0 +1,30 @@
+#!/bin/sh
+# Copyright (C) 2010 Red Hat, Inc. All rights reserved.
+#
+# This copyrighted material is made available to anyone wishing to use,
+# modify, copy, or redistribute it subject to the terms and conditions
+# of the GNU General Public License v.2.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+#
+# Testcase for bugzilla #621173 
+# excercises partition table scanning code path
+#
+
+which sfdisk || exit 200
+
+LVM_TEST_CONFIG_DEVICES="types = [\"device-mapper\", 142]"
+
+. ./test-utils.sh
+
+aux prepare_pvs 1 30
+
+pvs
+
+# create small partition table
+echo "1 2" | sfdisk $dev1
+
+pvs
diff --git a/test/test-utils.sh b/test/test-utils.sh
index cc13fa2..c1de6ca 100644
--- a/test/test-utils.sh
+++ b/test/test-utils.sh
@@ -371,6 +371,7 @@ prepare_lvmconf() {
     cache_dir = "$TESTDIR/etc"
     sysfs_scan = 0
     default_data_alignment = 1
+    $LVM_TEST_CONFIG_DEVICES
   }
   log {
     syslog = 0
-- 
1.7.3.1

[PATCH 0/2] Strict aliasing

[Petr Rockai]

Zdenek Kabelac <zkabelac@redhat.com> writes:
> Zdenek Kabelac (2):
>   Fix compiler warning about strict-aliasing break
>   Testcase for partition table scanning
Reviewed-by: Petr Rockai <prockai@redhat.com>

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