[pkg-gnupg-maint] Bug#568375: gnupg-agent: does not work with `git tag -s`

[Michal Hocko]

On Sun, Mar 20, 2016 at 12:12:00AM -0400, Peter Colberg wrote:
> Hi Luca,
> 
> On Thu, Feb 04, 2010 at 12:32:21PM +0100, Luca Capello wrote:
> > Package: gnupg-agent
> > Version: 2.0.14-1
> > Severity: important
> > 
> > Hi there!
> > 
> > It seems that `git tag -s` and gpg-agent fails to cooperate and do not
> > show the pinentry dialog (in my case the -curses variant inside screen):
> > =====
> > luca at gismo:~/Lab/thesis/text(git)[master]$ \
> >  git tag -s -u E397832F -m "submitted" submitted $COMMIT
> > 
> > You need a passphrase to unlock the secret key for
> > user: "Luca Capello <luca at pca.it>"
> > 4096-bit RSA key, ID 3BE9F36D, created 2009-07-01 (main key ID E397832F)
> > 
> > gpg: cancelled by user
> > gpg: skipped "E397832F": bad passphrase
> > gpg: signing failed: bad passphrase
> > error: gpg failed to sign the tag
> > error: unable to sign the tag
> 
> While this comes too late for signing the tag of your submitted thesis
> (congratulations!), this is likely caused by a missing GPG_TTY variable.
> 
> https://www.gnupg.org/documentation/manuals/gnupg/Common-Problems.html
> 
> The gpg-agent man page nowadays includes the following hint:
> 
>   It is important to set the GPG_TTY environment variable in your login
>   shell, for example in the ‘~/.bashrc’ init script:
> 
>   export GPG_TTY=$(tty)

So I've tried this and it didn't help.
$ export GPG_TTY=$(tty)
$ git tag -s -u $ID ...

I get the password dialog but nothing really happens after then.

16699 pts/1    S+     0:00         git tag -s -u B310E347
16700 pts/1    SL+    0:00           gpg --status-fd=2 -bsau B310E347

gpg is stuck waiting for an input
$ strace -p 16700
strace: Process 16700 attached
read(4,

$ ll /proc/16700/fd/4 
lrwx------ 1 miso miso 64 Jan 12 11:54 /proc/16700/fd/4 -> socket:[2711665]

but it never gets anything while gpg-agent is hogging the cpu
16703 ?        Ssl    3:05 gpg-agent --homedir /home/miso/.gnupg --use-standard-socket --daemon

Note that /proc/16703/environ contains GPG_TTY...

$ strace -fp 16703
strace: Process 16703 attached with 2 threads
strace: [ Process PID=16704 runs in x32 mode. ]
[pid 16703] pselect6(8, [3 4 5 6 7], NULL, NULL, NULL, {[], 8}

nothing really more, so it seems that the process is looping in the userspace.
Is there any way to disable gpg-agent altogether?

Thanks!
-- 
Michal Hocko