1981819e81
Let foo.odb be a database file that has a macro that connects to the
Database on "Open Document" event (and needs to prompt user for
user/password).
There was a race condition between two actions:
1) the asynchronous treatment of "OnFirstControllerConnected" in dbaui::OApplicationController,
which tries to get dbaui::OApplicationController's mutex
2) the StarBasic macro calling dbaui::OApplicationController::connect
which needs to display a dialog (to get username and password),
and thus puts that dialog in the main thread's event queue
and waits for it ... with dbaui::OApplicationController's mutex held
Now, if "1)" is before "2)" in the event queue of the the main thread,
*but* "1)" is executed *after* "2)" has taken the lock, there is a deadlock.
Fix:
1) Make OnFirstControllerConnected synchronous.
Make sure (by taking mutex in dbaui::OApplicationController::attachFrame, its ancestor in the call graph)
that nothing else will happen with the OApplicationController as long as it is not finished.
---> it does not need to take mutex itself anymore
This avoids the "order in the asynchronous events" dependency.
2) Change dbaui::OApplicationController::ensureConnection to do the user prompting
WITHOUT HOLDING the mutex, and use the mutex "only" to protect actually assigning
the connection to m_xDataSourceConnection.
Theoretically, in some race condition, we could connect twice and then discard one connection <shrug>.
ensureConnection will never return the discarded connection, though.
(I think I got that right with respect to http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html)
This keeps it from locking on another condition while holding the mutex.
Change-Id: Iab1bbec5d5df12bb89d027d43e498c78c92ffc32
Reviewed-on: https://gerrit.libreoffice.org/3310
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>
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| .. | ||
| inc | ||
| qa | ||
| source | ||
| uiconfig | ||
| util | ||
| win32/source/odbcconfig | ||
| AllLangResTarget_dba.mk | ||
| AllLangResTarget_dbmm.mk | ||
| AllLangResTarget_dbu.mk | ||
| AllLangResTarget_sdbt.mk | ||
| CppunitTest_dbaccess_macros_test.mk | ||
| Executable_odbcconfig.mk | ||
| JunitTest_dbaccess_complex.mk | ||
| JunitTest_dbaccess_unoapi.mk | ||
| Library_dba.mk | ||
| Library_dbaxml.mk | ||
| Library_dbmm.mk | ||
| Library_dbu.mk | ||
| Library_sdbt.mk | ||
| Makefile | ||
| Module_dbaccess.mk | ||
| Package_inc.mk | ||
| README | ||
| UIConfig_dbaccess.mk | ||
| UIConfig_dbapp.mk | ||
| UIConfig_dbbrowser.mk | ||
| UIConfig_dbquery.mk | ||
| UIConfig_dbrelation.mk | ||
| UIConfig_dbtable.mk | ||
| UIConfig_dbtdata.mk | ||
Database access tools, for "base" database application