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Re: Can't read lock file


On 11/11/2009 10:07, Corinna Vinschen wrote:
On Nov 11 07:40, Fergus wrote:
Q1. Is it still the case that this problem is "not well understood"
as in this reference?
    http://x.cygwin.com/docs/faq/cygwin-x-faq.html#q-cant-read-lock-file

Hardlinks don't work on FAT filesystems since FAT doesn't support them.
Up to Cygwin 1.7.0-60, hardlinks on FAT were faked by copying the file.
This has obvious downsides (unsecure, potential denial-of-service
problems, portability), so we discussed and decided to remove this fake
and to return an error instead when trying to create a hardlink on a FAT
FS: http://cygwin.com/ml/cygwin/2009-09/msg00208.html

(My experiments with possible cause/ cure are confounded because on
Machine 1 I have NTFS filesystems but lack administrator rights and
on Machine 2 where I am Administrator, all filesystems are FAT32.)

Which is bad since FAT32 has no security at all. Any process of any user on the machine can overwrite any file, even in the Windows folder. NTFS is much more secure and has a couple of features you never get with FAT32, and hardlinks are only one minor advantage. You should really update the filesystem to NTFS using the on-board convert.exe tool.

As for X, it should have a fallback method if the /tmp filesystem
doesn't support hardlinks.

Well, the fallback method is to use -nolock :-)


The only use of the lock file appears to be to stop people from doing things like starting 'X :0 -nolisten inet -nolisten inet6' and 'X :0 -nolisten unix' at the same time, so I'm kind of tempted just to make '-nolock' the default and let people run with scissors if they want to :-)

However, since there does seem to be some code to grovel over the mount options to try to detect if /tmp is textmode and warn about that for some reason, perhaps I'll look at checking if it's FAT and turning off the lockfile automatically in that case.

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