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Re: `CYGWIN=winsymlinks:nativestrict`, `ln -s target link` fails if target doesn't exist
- From: Gene Pavlovsky <gene dot pavlovsky at gmail dot com>
- To: cygwin at cygwin dot com
- Date: Fri, 29 Apr 2016 03:05:49 +0300
- Subject: Re: `CYGWIN=winsymlinks:nativestrict`, `ln -s target link` fails if target doesn't exist
- Authentication-results: sourceware.org; auth=none
- References: <CAPTiy3NUXprQL6V0+Njc2L7XfhpqtC7oWFwNMhOEFZ2OZmddoQ at mail dot gmail dot com> <1606116423 dot 20160429020650 at yandex dot ru>
I don't know if POSIX standard has something to say about that, but
here's a reference from GNU libc:
`man 2 symlink`:
> A symbolic link (also known as a soft link) may point to an existing file or to a nonexistent one; the latter case is known as a dangling link.
On 29 April 2016 at 02:06, Andrey Repin <firstname.lastname@example.org> wrote:
> Greetings, Gene Pavlovsky!
>> I have an issue to report:
>> Introduction: On a UNIX system, `ln -s target link` creates a link
>> regardless of target's existence.
>> This is used in some scripts, e.g. Gentoo's `run-crons` (which I also
>> use on Cygwin) uses a symlink pointing to the running process PID as
>> Issue: if `CYGWIN=winsymlinks:nativestrict` env var is set, running
>> `ln -s target link` completely fails (even though running `mklink link
>> target` in `cmd.exe` succeeds, same as `ln -s` does on UNIX). If
>> `CYGWIN=winsymlinks:native`, a non-native link is created.
>> So, `nativestrict` might break some (admittedly unorthodox) scripts.
>> With `native` these script work, but still a native link would be
>> preferrable and it is possible to create, but a non-native link is
>> created instead.
>> Bottom line, I think the native symlink creation code should be
>> checked and a possibility should be added to create links to
>> non-existent targets, rather than the current behavior of failing.
> This is actually an arguable behavior, even in Linux. I can imagine the
> behavior is "undefined" in such a case.
> But I'll leave final say to the more experienced members of the list.
> With best regards,
> Andrey Repin
> Friday, April 29, 2016 01:55:21
> Sorry for my terrible english...
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