Re: [HACKERS] Re: [HACKERS] Re: [HACKERS] Windows service is not starting so there’s message in log: FATAL: "could not create shared memory segment “Global/PostgreSQL.851401618”: Permission denied” - Mailing list pgsql-hackers

On Mon, Mar 14, 2016 at 4:51 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Fri, Mar 11, 2016 at 5:21 PM, Haribabu Kommi <kommi.haribabu@gmail.com>
> wrote:
>>
>> On Fri, Mar 11, 2016 at 12:00 AM, Amit Kapila <amit.kapila16@gmail.com>
>> wrote:
>>
>>
>> >> I am not able to find the reason for this error. This error is
>> >> occurring
>> >> only
>> >> when the PostgreSQL is started as a service only.
>> >>
>> >
>> > Did you use pg_ctl register/unregister to register different services.
>> > Can
>> > you share the detail steps and OS version on which you saw this
>> > behaviour?
>>
>> Operating system - windows 7
>> Binary - PostgreSQL 9.5 (This doesn't matter, 9.4+ can produce the
>> problem)
>>
>> 1. Create two standard users in the system (test_user1 and test_user2)
>> 2. Create two databases belongs each user listed above.
>> 3. Now using pg_ctl register the services for the two users.
>> 4. Provide logon permissions to these users to run the services by
>> changing
>> service properties.
>
> Did you mean to say that you changed Log on as: Local System Account in
> service properties or something else?

No. Not as local service. The user should be the new standard user
that is created
in the system.

>> 5. Now try to start the services, the second service fails with the
>> error message.
>> 6. Error details can be found out in Event log viewer.
>>
>
> If I follow above steps and do as I mentioned for step-4, I am not able to
> reproduce the issue on Windows-7 m/c using code of HEAD.

I am not able to start a service with HEAD code in the same machine, where
as it is working for 9.5. I will look into it later and update it.

>> Yes, it is working as same user services. The main problem is, PostgreSQL
>> as a service for two different users in the same system is not working
>> because
>> of same random getting generated for two services.
>>
>
> I am not sure why you think same random number is problem, as mentioned
> above, even if the dsm name is same due to same random number, the code has
> logic to process it appropriately (regenerate the name of dsm).  Having said
> that, I don't mean to say that we shouldn't have logic to generate unique
> name and I think we might want to add data dir path to name generation as we
> do for main shared memory, however it is better to first completely
> understand the underneath issue.

Yes, same random number generation is not the problem. In windows apart
from EEXIST error, EACCES also needs to be validated and returned for
new random number generation, instead of throwing an error.

> If I understand correctly, here the problem is due to the reason that the
> second user doesn't have appropriate access rights to access the object
> created by first user.  On reading the documentation of CreateFileMapping(),
> it seems that user should have SeCreateGlobalPrivilege privilege to create
> an object in Global namespace.  Can you once try giving that privilege to
> the users created by you?  To give this privilege, go to control
> panel->System And Security->Administrative Tools->Local Security
> Policy->Local Policies->User Rights Assignment, in the right window, select
> Create global objects and double-click the same and add the newly created
> users. Rerun your test after these steps.

Thanks for providing details. I added the two newly created objects into
create global objects, still the same error occurred.


Regards,
Hari Babu
Fujitsu Australia