[parted-devel] [PATCH 1/2] libparted: enforce dos partition limit
Jim Meyering
jim at meyering.net
Wed Jan 18 13:12:27 UTC 2012
Phillip Susi wrote:
> From: Phillip Susi <psusi at cfl.rr.com>
>
> The msdos partition table claimed a maximum partition count of 16
> but would allow you to go beyond that. This resulted in the kernel
> not being informed of those partitions. Corrected to enforce the
> limit.
> ---
> NEWS | 4 ++
> libparted/labels/dos.c | 12 +++++--
> tests/Makefile.am | 1 +
> tests/t9042-dos-partition-limit.sh | 69 ++++++++++++++++++++++++++++++++++++
> 4 files changed, 83 insertions(+), 3 deletions(-)
> create mode 100644 tests/t9042-dos-partition-limit.sh
>
> diff --git a/NEWS b/NEWS
> index 58a5f89..194903b 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -7,6 +7,10 @@ GNU parted NEWS -*- outline -*-
> parted has improved support for partitionable loopback devices
>
> ** Bug fixes
> + The msdos partition table claimed a maximum partition count of 16
> + but would allow you to go beyond that. This resulted in the kernel
> + not being informed of those partitions. Corrected to enforce the
> + limit.
...
> +n=$((n_MiB * sectors_per_MiB))
> +printf "BYT;\n$scsi_dev:${n}s:scsi:$ss:$ss:gpt:Linux scsi_debug;\n" \
> + > exp || fail=1
> +
> +parted -s $scsi_dev mklabel msdos || fail=1
> +parted -s -a min $scsi_dev mkpart extended 2046s 100% || fail=1
> +
> +i=1
> +while :; do
> + end=$((start + partition_sectors - 2))
> + parted -s -a min $scsi_dev mkpart logical ${start}s ${end}s || fail=1
> + printf "$i:${start}s:${end}s:${partition_sectors}s::p$i:;\n" >> exp
> + test $i = $((n_partitions - 1)) && break
> + start=$((start + partition_sectors))
> + i=$((i+1))
> +done
> +
> +start=$((start + partition_sectors))
> +end=$((start + partition_sectors - 2))
> +
> +#try one more partition than allowed, make sure it fails
> +
> +parted -s -a min $scsi_dev mkpart logical ${start}s ${end}s > out 2>&1
> +cat <<EOF > exp
> +Error: Can not create any more partitions
> +EOF
> +compare exp out || fail=1
Thanks for the fix and added test. And NEWS.
Almost perfect.
I've appended this to the commit log:
* NEWS (Bug fixes): Mention it.
* libparted/labels/dos.c (next_primary): Return -1 upon failure.
(next_logical): Stop no later than MAX_TOTAL_PART.
Throw exception and return -1 upon failure.
(msdos_partition_enumerate): Convert a negative partition number
return value from either of the above two to failure (return 0).
* tests/t9042-dos-partition-limit.sh: New file.
* tests/Makefile.am (TESTS): Add it.
and fixed the test:
- changed "gpt" artifact to "msdos"
- adjust the expected first partition output
- adjust the per-partition expected output generation
- generate actual listing output and use that expected output we generated
I.e., I've folded in this incremental:
diff --git a/tests/t9042-dos-partition-limit.sh b/tests/t9042-dos-partition-limit.sh
index e7e23a7..07e8f64 100644
--- a/tests/t9042-dos-partition-limit.sh
+++ b/tests/t9042-dos-partition-limit.sh
@@ -39,7 +39,9 @@ scsi_debug_setup_ sector_size=$ss dev_size_mb=$n_MiB > dev-name ||
scsi_dev=$(cat dev-name)
n=$((n_MiB * sectors_per_MiB))
-printf "BYT;\n$scsi_dev:${n}s:scsi:$ss:$ss:gpt:Linux scsi_debug;\n" \
+printf '%s\n' "BYT;" \
+ "$scsi_dev:${n}s:scsi:$ss:$ss:msdos:Linux scsi_debug;" \
+ "1:$((start-2))s:$((start-2+4098-1))s:4098s:::lba;" \
> exp || fail=1
parted -s $scsi_dev mklabel msdos || fail=1
@@ -49,12 +51,15 @@ i=1
while :; do
end=$((start + partition_sectors - 2))
parted -s -a min $scsi_dev mkpart logical ${start}s ${end}s || fail=1
- printf "$i:${start}s:${end}s:${partition_sectors}s::p$i:;\n" >> exp
+ printf "$((i+4)):${start}s:${end}s:$((end-start+1))s:::;\n" >> exp
test $i = $((n_partitions - 1)) && break
start=$((start + partition_sectors))
i=$((i+1))
done
+parted -m -s $scsi_dev u s p > out || fail=1
+compare exp out || fail=1
+
start=$((start + partition_sectors))
end=$((start + partition_sectors - 2))
Here's the complete patch:
>From b4351c7b7205afb6017d495407e49a1e20a80389 Mon Sep 17 00:00:00 2001
From: Phillip Susi <psusi at cfl.rr.com>
Date: Fri, 13 Jan 2012 16:21:51 -0500
Subject: [PATCH] libparted: enforce dos partition limit
The msdos partition table claimed a maximum partition count of 16
but would allow you to go beyond that. This resulted in the kernel
not being informed of those partitions. Corrected to enforce the
limit.
* NEWS (Bug fixes): Mention it.
* libparted/labels/dos.c (next_primary): Return -1 upon failure.
(next_logical): Stop no later than MAX_TOTAL_PART.
Throw exception and return -1 upon failure.
(msdos_partition_enumerate): Convert a negative partition number
return value from either of the above two to failure (return 0).
* tests/t9042-dos-partition-limit.sh: New file.
* tests/Makefile.am (TESTS): Add it.
---
NEWS | 4 ++
libparted/labels/dos.c | 12 ++++-
tests/Makefile.am | 1 +
tests/t9042-dos-partition-limit.sh | 74 ++++++++++++++++++++++++++++++++++++
4 files changed, 88 insertions(+), 3 deletions(-)
create mode 100644 tests/t9042-dos-partition-limit.sh
diff --git a/NEWS b/NEWS
index 58a5f89..194903b 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,10 @@ GNU parted NEWS -*- outline -*-
parted has improved support for partitionable loopback devices
** Bug fixes
+ The msdos partition table claimed a maximum partition count of 16
+ but would allow you to go beyond that. This resulted in the kernel
+ not being informed of those partitions. Corrected to enforce the
+ limit.
parted now exits nonzero for certain failures already diagnosed as "Error".
For example, before this change, parted would exit successfully in spite
diff --git a/libparted/labels/dos.c b/libparted/labels/dos.c
index fc89170..3f3effe 100644
--- a/libparted/labels/dos.c
+++ b/libparted/labels/dos.c
@@ -2398,17 +2398,22 @@ next_primary (const PedDisk* disk)
if (!ped_disk_get_partition (disk, i))
return i;
}
- return 0;
+ return -1;
}
static int _GL_ATTRIBUTE_PURE
next_logical (const PedDisk* disk)
{
int i;
- for (i=5; 1; i++) {
+ for (i=5; i<=MAX_TOTAL_PART; i++) {
if (!ped_disk_get_partition (disk, i))
return i;
}
+ ped_exception_throw (
+ PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
+ _("cannot create any more partitions"),
+ disk->dev->path);
+ return -1;
}
static int
@@ -2427,7 +2432,8 @@ msdos_partition_enumerate (PedPartition* part)
part->num = next_logical (part->disk);
else
part->num = next_primary (part->disk);
-
+ if (part->num == -1)
+ return 0;
return 1;
}
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 34b3bc5..77a1cae 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -63,6 +63,7 @@ TESTS = \
t9030-align-check.sh \
t9040-many-partitions.sh \
t9041-undetected-in-use-16th-partition.sh \
+ t9042-dos-partition-limit.sh \
t9050-partition-table-types.sh
EXTRA_DIST = \
diff --git a/tests/t9042-dos-partition-limit.sh b/tests/t9042-dos-partition-limit.sh
new file mode 100644
index 0000000..07e8f64
--- /dev/null
+++ b/tests/t9042-dos-partition-limit.sh
@@ -0,0 +1,74 @@
+#!/bin/sh
+# Ensure that parted enforces msdos partition limit
+
+# Copyright (C) 2010-2012 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+
+# This program 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 General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../parted
+
+require_root_
+require_scsi_debug_module_
+
+grep '^#define USE_BLKID 1' "$CONFIG_HEADER" > /dev/null ||
+ skip_ 'this system lacks a new-enough libblkid'
+
+ss=$sector_size_
+partition_sectors=256 # sectors per partition
+n_partitions=13 # how many partitions to create
+start=2048 # start sector for the first partition
+
+n_sectors=$(($start + n_partitions * partition_sectors))
+
+sectors_per_MiB=$((1024 * 1024 / ss))
+n_MiB=$(((n_sectors + sectors_per_MiB - 1) / sectors_per_MiB))
+# create memory-backed device
+scsi_debug_setup_ sector_size=$ss dev_size_mb=$n_MiB > dev-name ||
+ skip_ 'failed to create scsi_debug device'
+scsi_dev=$(cat dev-name)
+
+n=$((n_MiB * sectors_per_MiB))
+printf '%s\n' "BYT;" \
+ "$scsi_dev:${n}s:scsi:$ss:$ss:msdos:Linux scsi_debug;" \
+ "1:$((start-2))s:$((start-2+4098-1))s:4098s:::lba;" \
+ > exp || fail=1
+
+parted -s $scsi_dev mklabel msdos || fail=1
+parted -s -a min $scsi_dev mkpart extended 2046s 100% || fail=1
+
+i=1
+while :; do
+ end=$((start + partition_sectors - 2))
+ parted -s -a min $scsi_dev mkpart logical ${start}s ${end}s || fail=1
+ printf "$((i+4)):${start}s:${end}s:$((end-start+1))s:::;\n" >> exp
+ test $i = $((n_partitions - 1)) && break
+ start=$((start + partition_sectors))
+ i=$((i+1))
+done
+
+parted -m -s $scsi_dev u s p > out || fail=1
+compare exp out || fail=1
+
+start=$((start + partition_sectors))
+end=$((start + partition_sectors - 2))
+
+#try one more partition than allowed, make sure it fails
+
+parted -s -a min $scsi_dev mkpart logical ${start}s ${end}s > out 2>&1
+cat <<EOF > exp
+Error: cannot create any more partitions
+EOF
+compare exp out || fail=1
+
+Exit $fail
--
1.7.9.rc1.2.gccfe4
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