[PATCH] Cygwin: Add /dev/disk/by-label and /dev/disk/by-uuid symlinks
Christian Franke
Christian.Franke@t-online.de
Fri Nov 17 20:25:57 GMT 2023
Corinna Vinschen wrote:
> On Nov 17 18:53, Christian Franke wrote:
>> Corinna Vinschen wrote:
>>> ...
>>> I see. Admittedly, I don't know how Linux handles this either.
>> A quick test on Debian 12 with by-label suggests that the last duplicate
>> wins. Also not very sophisticated :-)
> Given this is all controlled by rather simple udev rules, see
> /usr/lib/udev/rules.d/60-persistent-storage.rules, that's not
> really surprising.
>
>> IIRC in the past I've seen in another of these directories (by-id?) that
>> '#N' was appended if duplicates occur.
> I don't see anything like that in 60-persistent-storage.rules, though.
> It has been removed at one point, it seems.
A quick followup to mark duplicates and (more important) avoid leading
spaces in NTFS serial number.
-------------- next part --------------
From 1e212814cfb17579105ead4835410bd74dfb188a Mon Sep 17 00:00:00 2001
From: Christian Franke <christian.franke@t-online.de>
Date: Fri, 17 Nov 2023 21:20:26 +0100
Subject: [PATCH] Cygwin: /dev/disk: Mark duplicates, fix serial number format
Keep ranges of duplicate names and append '#N' to each name.
Add missing leading zeros to output format of NTFS serial number.
No longer ignore null volume serial numbers.
Signed-off-by: Christian Franke <christian.franke@t-online.de>
---
winsup/cygwin/fhandler/dev_disk.cc | 38 ++++++++++++++----------------
1 file changed, 18 insertions(+), 20 deletions(-)
diff --git a/winsup/cygwin/fhandler/dev_disk.cc b/winsup/cygwin/fhandler/dev_disk.cc
index 016b4c7bc..131ffd935 100644
--- a/winsup/cygwin/fhandler/dev_disk.cc
+++ b/winsup/cygwin/fhandler/dev_disk.cc
@@ -64,10 +64,12 @@ sanitize_label_string (WCHAR *s)
/* Linux does not skip leading spaces. */
return sanitize_string (s, L'\0', L' ', L'_', [] (WCHAR c) -> bool
{
- /* Labels may contain characters not allowed in filenames.
- Linux replaces spaces with \x20 which is not an option here. */
+ /* Labels may contain characters not allowed in filenames. Also
+ replace '#' to avoid that duplicate markers introduce new
+ duplicates. Linux replaces spaces with \x20 which is not an
+ option here. */
return !((0 <= c && c <= L' ') || c == L':' || c == L'/' || c == L'\\'
- || c == L'"');
+ || c == L'#' || c == L'"');
}
);
}
@@ -304,11 +306,10 @@ partition_to_label_or_uuid(bool uuid, const UNICODE_STRING *drive_uname,
const NTFS_VOLUME_DATA_BUFFER *nvdb =
reinterpret_cast<const NTFS_VOLUME_DATA_BUFFER *>(ioctl_buf);
if (uuid && DeviceIoControl (volhdl, FSCTL_GET_NTFS_VOLUME_DATA, nullptr, 0,
- ioctl_buf, NT_MAX_PATH, &bytes_read, nullptr)
- && nvdb->VolumeSerialNumber.QuadPart)
+ ioctl_buf, NT_MAX_PATH, &bytes_read, nullptr))
{
/* Print without any separator as on Linux. */
- __small_sprintf (name, "%16X", nvdb->VolumeSerialNumber.QuadPart);
+ __small_sprintf (name, "%016X", nvdb->VolumeSerialNumber.QuadPart);
NtClose(volhdl);
return true;
}
@@ -327,13 +328,9 @@ partition_to_label_or_uuid(bool uuid, const UNICODE_STRING *drive_uname,
FILE_FS_VOLUME_INFORMATION *ffvi =
reinterpret_cast<FILE_FS_VOLUME_INFORMATION *>(ioctl_buf);
if (uuid)
- {
- if (!ffvi->VolumeSerialNumber)
- return false;
- /* Print with separator as on Linux. */
- __small_sprintf (name, "%04x-%04x", ffvi->VolumeSerialNumber >> 16,
- ffvi->VolumeSerialNumber & 0xffff);
- }
+ /* Print with separator as on Linux. */
+ __small_sprintf (name, "%04x-%04x", ffvi->VolumeSerialNumber >> 16,
+ ffvi->VolumeSerialNumber & 0xffff);
else
{
/* Label is not null terminated. */
@@ -610,7 +607,7 @@ get_by_id_table (by_id_entry * &table, fhandler_dev_disk::dev_disk_location loc)
if (!table)
return (errno_set ? -1 : 0);
- /* Sort by name and remove duplicates. */
+ /* Sort by name and mark duplicates. */
qsort (table, table_size, sizeof (*table), by_id_compare_name);
for (unsigned i = 0; i < table_size; i++)
{
@@ -619,12 +616,13 @@ get_by_id_table (by_id_entry * &table, fhandler_dev_disk::dev_disk_location loc)
j++;
if (j == i + 1)
continue;
- /* Duplicate(s) found, remove all entries with this name. */
- debug_printf ("removing duplicates %d-%d: '%s'", i, j - 1, table[i].name);
- if (j < table_size)
- memmove (table + i, table + j, (table_size - j) * sizeof (*table));
- table_size -= j - i;
- i--;
+ /* Duplicate(s) found, append "#N" to all entries. This never
+ introduces new duplicates because '#' never occurs in the
+ original names. */
+ debug_printf ("mark duplicates %u-%u of '%s'", i, j - 1, table[i].name);
+ size_t len = strlen (table[i].name);
+ for (unsigned k = i; k < j; k++)
+ __small_sprintf (table[k].name + len, "#%u", k - i);
}
debug_printf ("table_size: %d", table_size);
--
2.42.1
More information about the Cygwin-patches
mailing list