DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org A78B73858D39
Subject: util-linux-2.39.3-1: libblkid returns invalid physical_sector_size
To: cygwin AT cygwin DOT com
Message-ID: <0fb74540-3878-206d-b623-15437fe79b01@t-online.de>
Date: Sun, 31 Mar 2024 10:11:24 +0200
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From: Christian Franke via Cygwin <cygwin AT cygwin DOT com>
Reply-To: Christian Franke <Christian DOT Franke AT t-online DOT de>
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Sender: "Cygwin" <cygwin-bounces+archive-cygwin=delorie DOT com AT cygwin DOT com>
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Testcase:

# cygcheck -f /sbin/fdisk.exe
util-linux-2.39.3-1

# /sbin/fdisk.exe -l /dev/sdd
Disk /dev/sdd: 465.76 GiB, 500107862016 bytes, 976773168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 34359738880 bytes
I/O size (minimum/optimal): 34359738880 bytes / 34359738880 bytes
Disklabel type: dos
Disk identifier: 0x0ac1a23

Device     Boot Start       End   Sectors   Size Id Type
/dev/sdd1        2048 976769023 976766976 465.8G  7 HPFS/NTFS/exFAT

Partition 1 does not start on physical sector boundary.

# printf '0x%016x\n' 34359738880
0x0000000800000200


The problem is that libblkid expects the results of BLKIOMIN, BLKIOOPT 
and BLKPBSZGET as 64 bit 'unsigned long' but Cygwin only returns 32 bit 
'int':

- util-linux-2.39.3/libblkid/src/topology/ioctl.c:
...
static const struct topology_val {

     long  ioc;

     /* functions to set probing result */
     int (*set_ulong)(blkid_probe, unsigned long);
     int (*set_int)(blkid_probe, int);
     int (*set_u64)(blkid_probe, uint64_t);

} topology_vals[] = {
     { BLKALIGNOFF, NULL, blkid_topology_set_alignment_offset },
     { BLKIOMIN, blkid_topology_set_minimum_io_size },
     { BLKIOOPT, blkid_topology_set_optimal_io_size },
     { BLKPBSZGET, blkid_topology_set_physical_sector_size },
#ifdef BLKGETDISKSEQ
     { BLKGETDISKSEQ, .set_u64 = blkid_topology_set_diskseq },
#endif
     /* we read BLKSSZGET in topology.c */
};
...

- util-linux-2.39.3/libblkid/src/topology/topology.c:
...
struct blkid_struct_topology {
     unsigned long    alignment_offset;
     unsigned long    minimum_io_size;
     unsigned long    optimal_io_size;
     unsigned long    logical_sector_size;
     unsigned long    physical_sector_size;
     unsigned long   dax;
     uint64_t    diskseq;
};
...
int blkid_topology_set_physical_sector_size(blkid_probe pr, unsigned 
long val)
...

- newlib-cygwin/winsup/cygwin/fhandler/floppy.cc:
...
     case BLKIOMIN:
       debug_printf ("BLKIOMIN");
       *(int *)buf = (int) bytes_per_sector;
       break;
     case BLKIOOPT:
       debug_printf ("BLKIOOPT");
       *(int *)buf = (int) bytes_per_sector;
       break;
     case BLKPBSZGET:
       debug_printf ("BLKPBSZGET");
       *(int *)buf = (int) bytes_per_sector;
       break;
...


A quick fix which only works on LE platforms:

- util-linux-2.39.3/libblkid/src/topology/ioctl.c:
...
static int probe_ioctl_tp(blkid_probe pr,
...
         union {
             unsigned long ul;
             int i;
             uint64_t u64;
-        } data;
+        } data = { 0 };
...


Downgrading to util-linux-2.33.3-3 does not help. The related code 
differs, but has the same problem.

The fdisk variant in busybox-1.36.1-2 is not affected.

-- 
Regards,
Christian


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