Re: [ANNOUNCEMENT] TEST RELEASE: Cygwin 2.4.0-0.8

[Kacper Michajlow <kasper93 at gmail dot com>]

I forgot to say. I'm running Windows 10 1511 x64.

2015-12-06 21:21 GMT+01:00 Kacper Michajlow <kasper93@gmail.com>:
> 2015-12-06 19:57 GMT+01:00 Corinna Vinschen <corinna-cygwin@cygwin.com>:
>> Hi Cygwin friends and users,
>>
>>
>> I released a new TEST version of Cygwin, 2.4.0-0.8.
>>
>> This adds a new feature to cygpath, the -U flag, which allows to
>> generate /proc/cygdrive paths, which are unambiguous even if the
>> cygdrive prefix changes.  E.g.:
>>
>>   $ mount -p
>>   Prefix              Type         Flags
>>   /mnt                user         binmode
>>
>>   $ cygpath -D
>>   /mnt/c/Users/corinna/Desktop
>>
>>   $ ./cygpath -DU
>>   /proc/cygdrive/c/Users/corinna/Desktop
>>
>> I'd like to point out the Windows 10 1511 workaround added to 2.4.0-0.7
>> again since it's important that it gets tested:
>>
>> - Not a bug fix as such, but a workaround for new behaviour in Windows 10
>>   version 1511 64 bit.  This version introduces a problem which existed in
>>   a similar variation (just vice versa) in XP and Server 2003 64 bit as well.
>>   An unexpected stack arrangement when starting a 64 bit Cygwin application
>>   from a 32 bit application (e.g. 32 bit CMD.EXE) broke Cygwin's fork.
>>   Addresses: https://cygwin.com/ml/cygwin/2015-12/msg00003.html
>>
>>
>> ======================================================================
>>
>> Please, please, please test.
>>
>> If this code is acceptable, I will create an official 2.4.0 release
>> next week.
>>
>> ======================================================================
>>
>>
>> This is the "new POSIX ACL handling reloaded" release.
>>
>> In local testing I successfully integrated AuthZ into the current Cygwin
>> code to generate more correct user permissions by being able to generate
>> effective permissions for arbitrary users.
>>
>> This success convinced me that it might be possible to pick up the POSIX
>> permission rewrite originally targeted for the 2.0.0 release and try to
>> update it using AuthZ and generally revamp it to reflect effective
>> permissions better.
>>
>> My local testing looks good, but this is a major change, so this code
>> really needs a lot more testing in various scenarios.  Especially
>> some Windows ACLs created in corporate environments are often a hard
>> nut to crack, and the example from
>>
>> https://cygwin.com/ml/cygwin/2015-04/msg00513.html
>>
>> which was the ultimate downfall of the original implementation is
>> the stuff which needs some good testing.
>>
>> There's, as usual, a downside: AuthZ leans a bit to the slow side.
>> Cygwin caches information already gathered once on a per-process basis,
>> but in locally crafted worst case scenarios (`ls' on lots of file owned
>> by lots of different users and groups) the slowdown may be up to 25%.
>> But that's really just a worst case, in the usual scenarios the slowdown
>> should be mostly unnoticable.
>>
>> To alleviate the problem, the AuthZ code is fortunately only called for
>> non-Cygwin ACLs and Cygwin ACLs created before this release.  Within a
>> pure Cygwin environment (e.g., some build directory only used with
>> Cygwin tools) AuthZ should be practically unused.
>>
>> Apart from the aforementioned code changes to "just do it right", there
>> are two additional changes I implemented for this new POSIX ACL revamp
>> release:
>>
>> - I reverted the questionable change I added to 2.0.0-0.7 in terms of
>>   chmod group permission handling.  The original description of this
>>   change was:
>>
>>     If you have a non-trivial ACL with secondary accounts and thus a
>>     mask value, chmod is supposed to change only the mask, not the
>>     permissions of the primary group.  However, if the primary group has
>>     few permissions to begin with, the result is really surprising.  ls
>>     -l would, e.g., show read/write perms for the group, but the group
>>     might still have only read perms.
>>
>>     Personally I find this chmod behaviour really, really bad, so I took
>>     the liberty to change it in a way which gives a much less surprising
>>     result:  If you call chmod on a non-trivial ACL, the group
>>     permissions will be used for the primary group and the mask.
>>
>> - setfacl(1) now accepts the combination of the -b and -k options, just as
>>   on Linux.
>>
>> As for the description what this implementation strives for, please see
>> http://linux.die.net/man/5/acl
>>
>> ============================================================================
>>
>> What's new:
>> -----------
>>
>> - New, unified implementation of POSIX permission and ACL handling.  The
>>   new ACLs now store the POSIX ACL MASK/CLASS_OBJ permission mask, and
>>   they allow to inherit the S_ISGID bit.  ACL inheritance now really
>>   works as desired, in a limited, but theoretically equivalent fashion
>>   even for non-Cygwin processes.
>>
>>   To accommodate standard Windows ACLs, the POSIX permissions of the
>>   owner and all other users in the ACL are computed using the Windows
>>   AuthZ API.  This may slow down the computation of POSIX permissions
>>   noticably in some circumstances, but is generally more correct.  The
>>   new code also ignores SYSTEM and Administrators group permissions when
>>   computing the MASK/CLASS_OBJ permission mask on old ACLs, and it
>>   doesn't deny access to SYSTEM and Administrators group based on the
>>   value of MASK/CLASS_OBJ when creating the new ACLs.
>>
>>   The new code now handles the S_ISGID bit on directories as on Linux:
>>   Setting S_ISGID on a directory causes new files and subdirs created
>>   within to inherit its group, rather than the primary group of the user
>>   who created the file.  This only works for files and directories
>>   created by Cygwin processes.
>>
>> - New API: rpmatch.
>>
>>
>> What changed:
>> -------------
>>
>> - setfacl(1) now allows to use the -b and -k option combined to allow reducing
>>   an ACL to only reflect standard POSIX permissions.
>>
>> - Fix (numeric and monetary) decimal point and thousands separator in
>>   fa_IR and ps_AF locales to be aligned with Linux.
>>
>>
>> Bug Fixes
>> ---------
>>
>> - Not a bug fix as such, but a workaround for new behaviour in Windows 10
>>   version 1511 64 bit.  This version introduces a problem which existed in
>>   a similar variation (just vice versa) in XP and Server 2003 64 bit as well.
>>   An unexpected stack arrangement when starting a 64 bit Cygwin application
>>   from a 32 bit application (e.g. 32 bit CMD.EXE) broke Cygwin's fork.
>>   Addresses: https://cygwin.com/ml/cygwin/2015-12/msg00003.html
>>
>> - Replaced old, buggy strtold implementation with well-tested gdtoa version
>>   from David M. Gay.
>>   Addresses: https://cygwin.com/ml/cygwin/2015-11/msg00205.html
>>
>> - Fix handling of relative paths in native symlinks if the target is in a
>>   drive's root dir or one level below.
>>   Addresses: https://cygwin.com/ml/cygwin/2015-11/msg00277.html
>>
>> - Fix a SEGV when calling `kill -l 0'.
>>   Addresses: https://cygwin.com/ml/cygwin/2015-11/msg00430.html
>>
>> - Fix a race condition in signal handling.
>>   Addresses: https://cygwin.com/ml/cygwin/2015-11/msg00387.html
>>
>> ============================================================================
>>
>>
>> Have fun,
>> Corinna
>>
>> --
>> Corinna Vinschen                  Please, send mails regarding Cygwin to
>> Cygwin Maintainer                 cygwin AT cygwin DOT com
>> Red Hat
>>
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>
>
> Hi,
>
> Since 2015-12-03 snapshot I got only black screen when running this batch script
> @echo off
> C:
> chdir C:\cygwin\bin
> zsh -l -i
>
> Basically it deadlocks while processing .zshrc. I was debugging this
> and it locks when loading "oh my zsh".
>
> Long story short is seems to hang here
> https://github.com/robbyrussell/oh-my-zsh/blob/master/lib/git.zsh#L177
> at least for the first time, because if I remove this line it hangs
> somewhere else. It basically hangs if in git_compare_version() is any
> kind of external command which cause fork.
>
> It works fine when running from mintty.

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