Accessing the keyring in a thread make the program crash (was find_credentials segfaults)

It looks like calling keyring_get_credentials from a thread is not safe.
I propose renaming the current one keyring_get_credentials_sync.
Also I propose not using a thread in the new find_credentials and using the async way of accessing the keyring instead.

Performing tests with trunk code I've got:

nessita@dali:~/canonical/ubuntu-sso-client/trunk$ killall ubuntu-sso-login; DEBUG=True PYTHONPATH=. ./bin/ubuntu-sso-login
ubuntu-sso-login: no process found
Hooking up SIGHUP with handler <function sighup_handler at 0x23d47d0>.
Starting Ubuntu SSO login manager for bus 'com.ubuntu.sso'.
keyring_delete_credentials: app_name "a".
keyring_delete_credentials: app_name "a".
**
ERROR:gkr-operation.c:342:on_pending_call_notify: assertion failed: (pending == op->pending)
Segmentation fault
nessita@dali:~/canonical/ubuntu-sso-client/trunk$

Accepted ubuntu-sso-client into maverick-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

Tested on a clean maverick install with -proposed enabled. Problem is very tricky to reproduce on maverick, but I can confirm I never got the seg fault.

This bug was fixed in the package ubuntu-sso-client - 1.1.1-0ubuntu1

---------------
ubuntu-sso-client (1.1.1-0ubuntu1) natty; urgency=low

  * New upstream release (1.1.1):

    [ Alejandro J. Cura <email address hidden> ]
      * Call the dbus mainloop thread init (fixes LP: #656545).

    [ Natalia B. Bidart <email address hidden> ]
      * Added the new dbus iface to the executable. Deprecated a few Dbus
      constants.

    [ Natalia B. Bidart <email address hidden> ]
      * Adding a new DBus iface to manage credentials with flexible API (LP:
      #653113).

    [ Natalia B. Bidart <email address hidden> ]
      * Replace twisted gtk reactor with the standard gtk mainloop. (LP:
      #655327).

    [ Natalia B. Bidart <email address hidden> ]
      * The TC browser will not be shown until the TOS page has been loaded. A
      spinner is shown in the mean time (LP: #620456).
      * The TC browser does not allow link navigation other than the TOS page
      (LP: #616961).

    [ Natalia B. Bidart <email address hidden> ]
      * Terms and conditions label is now translatable. Added a button to be
      able to browse the TC (LP: 654534).

    [ Natalia B. Bidart <email address hidden> ]
      * Moved logic from DBus SSOCredentials module into a self-contained, DBus
      agnostic module called 'credentials' (LP: #653113).

    [ Natalia B. Bidart <email address hidden> ]
      * Isolating SSO login processor into a separated module (LP: #637204).

    [ Natalia B. Bidart <email address hidden> ]
      * Cleanup code and modules to prepare the code for the DBus API refactor.

    [ Natalia B. Bidart <email address hidden> ]
      * Made entries name to be unicode to avoid a faulty capitalization when
      using turkish locale (LP: #652939).

    [ Natalia B. Bidart <email address hidden> ]
      * Workaround for LP: #467397 (when using turkish locale, decimal module
      import fails).

    [ Natalia B. Bidart <email address hidden> ]
      * Added encoding declaration on every file. Fixed error passing from GUI
      in GTK signals (LP: #652318).

    [ Natalia B. Bidart <email address hidden> ]
      * Avoiding calling a callback twice for buttons (LP: #652248).

    [ Natalia B. Bidart <email address hidden> ]
      * Removed unneeded assert sentences and replaced with warning logging
      when necessary (LP: #649317).

  * New upstream release (1.1.0):

    [ Natalia B. Bidart <email address hidden> ]
      * Avoiding having the main window freezing when pinging the U1 server
      (LP: #645162).

    [ Natalia B. Bidart <email address hidden> ]
      * Do not create the login keyring, use default instead (LP: #639690).

    [ Natalia B. Bidart <email address hidden> ]
      * Avoid duplicating logging messages for module "main" (LP: #638981).

    [ Natalia B. Bidart <email address hidden> ]
      * Delay import of webkit to be able to build on non-graphical envs (LP:
      #628956).
 -- Natalia Bidart (nessita) <email address hidden> Mon, 11 Oct 2010 10:22:28 -0300

This bug was fixed in the package ubuntu-sso-client - 1.0.4-0ubuntu1

---------------
ubuntu-sso-client (1.0.4-0ubuntu1) maverick-proposed; urgency=low

  * New upstream release:

  [ Alejandro J. Cura <email address hidden> ]
    * Replace twisted gtk reactor with the standard gtk mainloop. (LP: #655327).

  [ Alejandro J. Cura <email address hidden> ]
    * Call the dbus mainloop thread init (fixes LP: #656545).

  * Adding .bzr-builddeb/default.conf as per Michael Vog (mvo) request.

  * Adding dpkg (>= 1.15.7.2) as Pre-Depends (fixes LP: #658768).

  * Adding gnome-keyring as dep since python-gnomekeyring doesn't install it.
 -- Natalia Bidart (nessita) <email address hidden> Tue, 12 Oct 2010 10:07:55 -0300

We have a recent case of segfault within ubuntu-sso-client for maverick release, so I'll be reopening this bug.

Accepted ubuntu-sso-client into maverick-proposed, the package will build now and be available in a few hours. Please test and give feedback here. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

I was able to consistently reproduce this bug before, but with -proposed it's fixed now for me.

This bug was fixed in the package ubuntu-sso-client - 1.0.7-0ubuntu1

---------------
ubuntu-sso-client (1.0.7-0ubuntu1) maverick-proposed; urgency=low

  * New upstream release (1.0.6, 1.0.7):

    [ Natalia B. Bidart <email address hidden> ]
      * Added a new DBus signal UserNotValidated to indicate when a user is
      registered but not validated (LP: #667899).
      * Added new workflow so email validation is requested if necessary.
      * The verify email page should be always built, not only on registration.

    [ Alejandro J. Cura <email address hidden> ]
      * Store credentials on the keyring *only* from the main thread (LP:
      #656545).

  * New upstream release (1.0.5):

    [ Natalia B. Bidart <email address hidden> ]

      * Credentials are removed if the pinging to the server fails or any
      other exception occurs (LP: #660516).
 -- Natalia Bidart (nessita) <email address hidden> Thu, 04 Nov 2010 09:21:00 -0300

This bug was fixed in the package ubuntu-sso-client - 1.1.5-0ubuntu1

---------------
ubuntu-sso-client (1.1.5-0ubuntu1) natty; urgency=low

  * New upstream release (1.1.5):

    [ Natalia B. Bidart <email address hidden> ]
      * Use "org.freedesktop.secrets" dbus service instead of
      "org.gnome.keyring" (LP: #683088).

  * New upstream release (1.1.4):

    [ Natalia B. Bidart <email address hidden> ]
      * Added a gtk.Notebook to ensure proper window resize at startup
        (LP: #682669).
      * Enabled window resizing to be more user friendly.
      * Remove outdated references to gnome keyring from docstrings.

  * New upstream release (1.1.3):

    [ Natalia B. Bidart <email address hidden> ]
      * Make UI more friendly to resizes and big fonts (LP: #627496).
      * Splitting GUI code out of backend (LP: #677518).
      * Credentials can now be stored using a DBus called (LP: #680253).
      * Status from SSO server is now case sensitive (LP: #653165).
      * Credentials should not be cleared if the ping wasn't made due to empty
        ping url (LP: #676679).

    [ Rodney Dawes <email address hidden> ]
     * Add the utils sub-package to the packages declaration so it installs
     (LP: #680593).

    [ Alejandro J. Cura <email address hidden> ]
      * Fully async keyring access thru DBus. Drops dependency with
      gnomekeyring (LP: #656545).
 -- Natalia Bidart (nessita) <email address hidden> Tue, 30 Nov 2010 10:22:11 -0300