Add --chuid to gpg, gpg-card, and gpg-connect-agent.

* g10/gpg.c (oChUid): New.
(opts): Add --chuid.
(main): Implement --chuid.  Delay setting of homedir until the new
chuid is done.
* sm/gpgsm.c (main): Delay setting of homedir until the new chuid is
done.
* tools/gpg-card.c (oChUid): New.
(opts): Add --chuid.
(changeuser): New helper var.
(main): Implement --chuid.
* tools/gpg-connect-agent.c (oChUid): New.
(opts): Add --chuid.
(main): Implement --chuid.
--

Signed-off-by: Werner Koch <wk@gnupg.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/doc/gpg-card.texi b/doc/gpg-card.texi
index be19704cc..60107176b 100644
--- a/doc/gpg-card.texi
+++ b/doc/gpg-card.texi
@@ -125,6 +125,16 @@ Specify a non-default gpg binary to be used by certain commands.
 @opindex gpgsm-program
 Specify a non-default gpgsm binary to be used by certain commands.
 
+@item --chuid @var{uid}
+@opindex chuid
+Change the current user to @var{uid} which may either be a number or a
+name.  This can be used from the root account to run gpg-card for
+another user.  If @var{uid} is not the current UID a standard PATH is
+set and the envvar GNUPGHOME is unset.  To override the latter the
+option @option{--homedir} can be used.  This option has only an effect
+when used on the command line.  This option has currently no effect at
+all on Windows.
+
 @end table
 
 @mansect notes (OpenPGP)