68 lines
2.3 KiB
Diff
68 lines
2.3 KiB
Diff
From 3a493033ce3867a2561d60c1016dd0c03999e5eb Mon Sep 17 00:00:00 2001
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From: Karel Zak <kzak@redhat.com>
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Date: Tue, 18 Sep 2007 15:29:59 +0200
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Subject: [PATCH] libblkid: FAT magic is not on strict position when there is a real MBR
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There is _optional_ reserved space before FAT:
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boot | reserved | FAT | FAT | root | data
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sector | space | 1 | 2 | dir | region
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for more details see:
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http://en.wikipedia.org/wiki/File_Allocation_Table
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The probe_fat() code already expects reserved space and other optional
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junk in MBR+FAT, but the blkid_magic array expects strictly defined
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positions of FAT magic strings. That's correct for 99% partitions, but
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not for situation when on the same partition is real MBR. We need to check
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for FAT filesystem also when we detect MBR signature (0x55AA on address 510).
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The blkid is not able to detect vfat on USB Disks where is only one
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bootable partition with vfat, for example:
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# file -s /dev/sdc1
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/dev/sdc1: x86 boot sector; GRand Unified Bootloader, stage1 version
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0x3, 1st sector stage2 0x44ae, code offset 0x48, sectors/cluster 8,
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Media descriptor 0xf8, heads 4, sectors 3901408 (volumes > 32 MB) ,
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physical drive 0xdb, physical drive 0x5b, reserved 0xe, dos < 4.0
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BootSector (0x0)
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# vol_id /dev/sdc1
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ID_FS_USAGE=filesystem
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ID_FS_TYPE=vfat
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ID_FS_VERSION=FAT32
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ID_FS_UUID=0044-AE80
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ID_FS_UUID_ENC=0044-AE80
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ID_FS_LABEL=Mdv_Flash
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ID_FS_LABEL_ENC=Mdv_Flash
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ID_FS_LABEL_SAFE=Mdv_Flash
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old version:
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# blkid /dev/sdc1
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fixed version:
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# blkid /dev/sdc1
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/dev/sdc1: LABEL="MDV_FLASH" UUID="0044-AE80" TYPE="vfat"
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Signed-off-by: Karel Zak <kzak@redhat.com>
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---
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lib/blkid/probe.c | 1 +
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1 files changed, 1 insertions(+), 0 deletions(-)
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diff --git a/lib/blkid/probe.c b/lib/blkid/probe.c
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index d56292e..42ec234 100644
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--- a/lib/blkid/probe.c
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+++ b/lib/blkid/probe.c
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@@ -849,6 +849,7 @@ static struct blkid_magic type_array[] = {
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{ "vfat", 0, 0x36, 8, "FAT12 ", probe_fat },
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{ "vfat", 0, 0, 2, "\353\220", probe_fat_nomagic },
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{ "vfat", 0, 0, 1, "\351", probe_fat_nomagic },
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+ { "vfat", 0, 0x1fe, 2, "\125\252", probe_fat },
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{ "minix", 1, 0x10, 2, "\177\023", 0 },
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{ "minix", 1, 0x10, 2, "\217\023", 0 },
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{ "minix", 1, 0x10, 2, "\150\044", 0 },
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--
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1.5.2.4
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