dcavalca / rpms / util-linux

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diff -up util-linux-2.23.2/libblkid/src/partitions/dos.c.kzak util-linux-2.23.2/libblkid/src/partitions/dos.c
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--- util-linux-2.23.2/libblkid/src/partitions/dos.c.kzak	2015-08-21 10:16:45.244332027 +0200
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+++ util-linux-2.23.2/libblkid/src/partitions/dos.c	2015-08-21 10:22:07.181340367 +0200
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@@ -151,16 +151,6 @@ static int probe_dos_pt(blkid_probe pr,
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 	if (memcmp(data, BLKID_AIX_MAGIC_STRING, BLKID_AIX_MAGIC_STRLEN) == 0)
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 		goto nothing;
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-	/*
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-	 * Now that the 55aa signature is present, this is probably
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-	 * either the boot sector of a FAT filesystem or a DOS-type
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-	 * partition table.
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-	 */
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-	if (blkid_probe_is_vfat(pr) == 1) {
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-		DBG(LOWPROBE, blkid_debug("probably FAT -- ignore"));
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-		goto nothing;
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-	}
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-
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 	p0 = (struct dos_partition *) (data + BLKID_MSDOS_PT_OFFSET);
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 	/*
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@@ -182,6 +172,16 @@ static int probe_dos_pt(blkid_probe pr,
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 		}
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 	}
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+	/*
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+	 * Now that the 55aa signature is present, this is probably
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+	 * either the boot sector of a FAT filesystem or a DOS-type
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+	 * partition table.
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+	 */
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+	if (blkid_probe_is_vfat(pr) == 1) {
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+		DBG(LOWPROBE, blkid_debug("probably FAT -- ignore"));
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+		goto nothing;
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+	}
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+
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 	blkid_probe_use_wiper(pr, BLKID_MSDOS_PT_OFFSET,
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 				  512 - BLKID_MSDOS_PT_OFFSET);
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diff -up util-linux-2.23.2/libblkid/src/partitions/dos.h.kzak util-linux-2.23.2/libblkid/src/partitions/dos.h
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--- util-linux-2.23.2/libblkid/src/partitions/dos.h.kzak	2015-08-21 10:34:14.919380422 +0200
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+++ util-linux-2.23.2/libblkid/src/partitions/dos.h	2015-08-21 10:35:45.221807669 +0200
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@@ -12,6 +12,12 @@ struct dos_partition {
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 #define BLKID_MSDOS_PT_OFFSET		0x1be
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+static inline struct dos_partition *mbr_get_partition(unsigned char *mbr, int i)
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+{
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+	return (struct dos_partition *)
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+		(mbr + BLKID_MSDOS_PT_OFFSET + (i * sizeof(struct dos_partition)));
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+}
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+
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 /* assemble badly aligned little endian integer */
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 static inline unsigned int assemble4le(const unsigned char *p)
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 {
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diff -up util-linux-2.23.2/libblkid/src/superblocks/vfat.c.kzak util-linux-2.23.2/libblkid/src/superblocks/vfat.c
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--- util-linux-2.23.2/libblkid/src/superblocks/vfat.c.kzak	2015-08-21 10:10:12.111906711 +0200
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+++ util-linux-2.23.2/libblkid/src/superblocks/vfat.c	2015-08-21 10:35:07.733045452 +0200
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@@ -16,6 +16,7 @@
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 #include <ctype.h>
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 #include <stdint.h>
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+#include "partitions/dos.h"
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 #include "superblocks.h"
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 /* Yucky misaligned values */
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@@ -169,7 +170,8 @@ static unsigned char *search_fat_label(b
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 	return NULL;
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 }
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-static int fat_valid_superblock(const struct blkid_idmag *mag,
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+static int fat_valid_superblock(blkid_probe pr,
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+			const struct blkid_idmag *mag,
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 			struct msdos_super_block *ms,
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 			struct vfat_super_block *vs,
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 			uint32_t *cluster_count, uint32_t *fat_size)
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@@ -243,6 +245,20 @@ static int fat_valid_superblock(const st
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 	if (cluster_count)
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 		*cluster_count = __cluster_count;
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+	if (blkid_probe_is_wholedisk(pr)) {
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+		/* OK, seems like FAT, but it's possible that we found boot
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+		 * sector with crazy FAT-like stuff (magic strings, media,
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+		 * etc..) before MBR. Let's make sure that there is no MBR with
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+		 * usable partition. */
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+		unsigned char *buf = (unsigned char *) ms;
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+		if (is_valid_mbr_signature(buf)) {
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+			struct dos_partition *p0 = mbr_get_partition(buf, 0);
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+			if (dos_partition_size(p0) != 0 &&
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+			    (p0->boot_ind == 0 || p0->boot_ind == 0x80))
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+				return 0;
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+		}
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+	}
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+
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 	return 1;	/* valid */
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 }
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@@ -270,7 +286,7 @@ int blkid_probe_is_vfat(blkid_probe pr)
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 	if (!vs)
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 		return errno ? -errno : 0;
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-	return fat_valid_superblock(mag, ms, vs, NULL, NULL);
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+	return fat_valid_superblock(pr, mag, ms, vs, NULL, NULL);
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 }
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 /* FAT label extraction from the root directory taken from Kay
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@@ -293,7 +309,7 @@ static int probe_vfat(blkid_probe pr, co
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 	if (!vs)
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 		return errno ? -errno : 1;
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-	if (!fat_valid_superblock(mag, ms, vs, &cluster_count, &fat_size))
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+	if (!fat_valid_superblock(pr, mag, ms, vs, &cluster_count, &fat_size))
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 		return 1;
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 	sector_size = unaligned_le16(&ms->ms_sector_size);