On Feb 29 14:10, Rainer Emrich wrote:
> I try to reliably determine if native Windows symlink are working for a
> current cygwin environment in a shell script.
>
> Therefor I used a powershell snipped:
>
> mkdir asdfgh
> ln -s asdfgh/ asdfgh-1
> powershell "& {Get-Item -Path asdfgh-1 | Select-Object}"
>
> On cygwin 3.0.7 the output is as follows:
>
>
> Directory: D:\cygwin\home\rainer\temp
>
>
> Mode LastWriteTime Length Name
> ---- ------------- ------ ----
> d----l 29.02.2020 13:58 asdfgh-1
>
> On cygwin 3.1.4 I get:
>
>
> Directory: D:\cygwin\home\rainer\temp
>
>
> Mode LastWriteTime Length Name
> ---- ------------- ------ ----
> d---- 29.02.2020 13:58 asdfgh-1
>
> So now there is no indication that this is a link. Is this new behaviour
> intended or a bug?
>
> I did not try on Windows 10, I'm still on windows 7.
>
> Rainer
>
I can't reproduce this behaviour. Keep in mind that, by default, you
*have to* run in an elevated shell to be able to create native NTFS
symlinks, *and* you *have to* set the environment variable CYGWIN(*) to
contain "winsymlinks:native" or "winsymlinks:nativestrict". The latter
is nice for testing, it refuses to fall back silently to the default
Cygwin-only symlinks but fails instead if it can't create a native
NTFS symlink.
So, on Windows 7 in an elevated shell:
# id -G | grep -Eq '\<544\>' && echo elevated || echo non-elevated
elevated
# uname -a
CYGWIN_NT-6.1 vmbert764 3.1.4(0.340/5/3) 2020-02-19 08:49 x86_64 Cygwin
# mkdir qwe
# cd qwe
# export CYGWIN="winsymlinks:nativestrict"
# touch foo
# ln -s foo bar
# cmd /c dir /a
Volume in drive C has no label.
Volume Serial Number is A8E0-A24E
Directory of C:\cygwin64\home\corinna\qwe
2020-03-02 17:31 <DIR> .
2020-03-02 17:31 <DIR> ..
2020-03-02 17:31 <SYMLINK> bar [foo]
2020-03-02 17:31 0 foo
2 File(s) 0 bytes
2 Dir(s) 7.907.352.576 bytes free
In a non-elevated shell:
$ id -G | grep -Eq '\<544\>' && echo elevated || echo non-elevated
non-elevated
$ uname -r
CYGWIN_NT-6.1 vmbert764 3.1.4(0.340/5/3) 2020-02-19 08:49 x86_64 Cygwin
$ cd qwe
$ export CYGWIN="winsymlinks:nativestrict"
$ rm bar
$ ln -s foo bar
ln: failed to create symbolic link 'bar': Operation not permitted
$ export CYGWIN="winsymlinks:native" # !!!
$ ln -s foo bar
$ cmd /c dir /a
Volume in drive C has no label.
Volume Serial Number is A8E0-A24E
Directory of C:\cygwin64\home\corinna\qwe
2020-03-02 17:31 <DIR> .
2020-03-02 17:31 <DIR> ..
2020-03-02 17:38 20 bar
2020-03-02 17:31 0 foo
2 File(s) 20 bytes
2 Dir(s) 7.907.352.576 bytes free
The symlink created last is a Cygwin-only symlink (special file
with SYSTEM attribute), not a native symlink.
Corinna
(*) https://cygwin.com/cygwin-ug-net/using-cygwinenv.html
(*) https://cygwin.com/cygwin-ug-net/using.html#pathnames-symlinks
--
Corinna Vinschen
Cygwin Maintainer
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