BUG #6735: PANIC: 42501: could not open control file "global/pg_control": Permission denied

On 07/13/2012 09:00 PM, tsialiam@gmail.com wrote:

The following bug has been logged on the website:

Bug reference: 6735
Logged by: Petros Tsialiamanis
Email address: tsialiam@gmail.com
PostgreSQL version: 8.3.5
Operating system: WinXP Pro SP3
Description:

Hi,
The first time I started the postgresql server as 'Local System' user and I
created the PGDATA. Now I am trying to start the postgresql server again as
'pss-svc' user which is member of Administrators group and I take the
following error message (I've changed the debug log level)

The server shouldn't crash at the end, but otherwise this is all
misconfiguration of your system. If you change the service account, you
need to change the permissions on the PostgreSQL data directory to match
the new service account credentials.

DEBUG: 00000: mapped win32 error code 5 to 13
LOCATION: _dosmaperr, .\src\port\win32error.c:182
PANIC: 42501: could not open control file "global/pg_control": Permission
denied
LOCATION: ReadControlFile, .\src\backend\access\transam\xlog.c:3904

This application has requested the Runtime to terminate it in an unusual
way.
Please contact the application's support team for more information.
server starting

I'm not sure why it's crashing here, but you're running such an ancient
version that it's hard to care. If you can reproduce the crash with the
latest 8.3 point release it might be worth a look.

--
Craig Ringer

On 07/14/2012 12:18 AM, Petros Tsialiamanis wrote:

Thank you very much for your reply.

Thanks for coming back and re-testing with a modern PostgreSQL.

PostgreSQL 9.1 isn't compatible with databases from 8.3, so you can't
actually run Pg 9.1 directly against a datadir from 8.3; that's why I
suggested the latest 8.3 point release.

However, your startup should be failing with a message telling you this,
not with a permissions error then (more importantly) a crash.

Is there any antivirus software on this computer? If so, what is it?
Does excluding the PostgreSQL data directory, PostgreSQL executable
directory, and (if the AV supports it) adding process exclusions for
"postmaster.exe" and "postgres.exe" have any effect?

The 'pss-svc' user is member of the administrators group and has full
permissions for PostgreSQL data directory.

It clearly doesn't, because PostgreSQL is getting "permission denied"
from the OS when accessing global/pg_control. Maybe you need to apply
permissions recursively?

Remember that on Win7, membership of the Administrators group doesn't
grant the ability to perform file operations as administrator directly.
It grants the ability to create privileged processes that can then
perform those operations using implicit or explicit "run as
administrator" functionality.

I can't off the top of my head think of a safe way on Windows to test if
a file is writable as a given user without potentially changing its
contents. On Linux I'd say "run touch /path/name" but there's no touch
command on Windows. global\pg_control is a binary file so you can't just
open it and save it in notepad (DO NOT DO THIS) as it'll corrupt it
hopelessly, and Windows doesn't come with a binary-safe editor.

I reproduced the crash with PostgreSQL version 9.1.4.12152 with the
following output :

[snip]

LOCATION: _dosmaperr, .\src\port\win32error.c:186
PANIC: 42501: could not open control file "global/pg_control":
Permission denied
LOCATION: ReadControlFile, .\src\backend\access\transam\xlog.c:4687

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.
******************************************************************

OK, that's not very nice behaviour - it should be doing a clean exit
after it fails to read global/pg_control . Hmm. I'm not sure off the top
of my head how to tackle tracking that down without a debugger. I don't
really have time at the moment to set up a test environment under
Windows and see if I can reproduce it.

Ideas anyone? Can someone with a Windows box use pg_ctl to try to start
a new Pg instance against a datadir with an unwritable pg_control ?

--
Craig Ringer

On 07/13/12 6:00 AM, tsialiam@gmail.com wrote:

PANIC: 42501: could not open control file "global/pg_control": Permission
denied

start a CMD prompt ('dos') via 'run as admin'.
from this privileged command window,

CACLS \path\to\pg\data /T /E /G pss-svc:(OI)(CI)F

then try restarting postgres.

LOCAL_SYSTEM created the files, and owns them.

Oh, the pss-svc user should not be a member of Administrators.

--
john r pierce N 37, W 122
santa cruz ca mid-left coast

Craig Ringer <ringerc@ringerc.id.au> writes:

PostgreSQL 9.1 isn't compatible with databases from 8.3, so you can't
actually run Pg 9.1 directly against a datadir from 8.3; that's why I
suggested the latest 8.3 point release.

However, your startup should be failing with a message telling you this,
not with a permissions error then (more importantly) a crash.

Well, the reason that's a PANIC is that ReadControlFile is coded that
way:

fd = BasicOpenFile(XLOG_CONTROL_FILE,
O_RDWR | PG_BINARY,
S_IRUSR | S_IWUSR);
if (fd < 0)
ereport(PANIC,
(errcode_for_file_access(),
errmsg("could not open control file \"%s\": %m",
XLOG_CONTROL_FILE)));

Perhaps it should be only FATAL instead, but that seems like a quibble.
If it can't read pg_control, the server ain't starting.

It is curious though that the OP gets this far, because the server
would previously have tried to read PG_VERSION and postgresql.conf,
which if it were a simple wrong-account problem should likewise
have been unreadable. Your thought about AV software may be the
right explanation.

regards, tom lane

On 14 July 2012 05:56, Craig Ringer <ringerc@ringerc.id.au> wrote:

On 07/14/2012 12:18 AM, Petros Tsialiamanis wrote:

Thank you very much for your reply.

Thanks for coming back and re-testing with a modern PostgreSQL.

PostgreSQL 9.1 isn't compatible with databases from 8.3, so you can't
actually run Pg 9.1 directly against a datadir from 8.3; that's why I
suggested the latest 8.3 point release.

However, your startup should be failing with a message telling you this, not
with a permissions error then (more importantly) a crash.

Sorry for the misunderstanding.
When I said that I reproduced the error in 9.1 version, I mean that I
created the PGDATA with 9.1 postgresql server as 'local system' user
and after that I tried to start the postgresql server as 'pss-svc'
user and I took the error message which I sent with my previous mail.
So there isn't any incompatibility problem with PGDATA.

Is there any antivirus software on this computer? If so, what is it? Does
excluding the PostgreSQL data directory, PostgreSQL executable directory,
and (if the AV supports it) adding process exclusions for "postmaster.exe"
and "postgres.exe" have any effect?

There isn't any antivirus software on my computer.

The 'pss-svc' user is member of the administrators group and has full
permissions for PostgreSQL data directory.

It clearly doesn't, because PostgreSQL is getting "permission denied" from
the OS when accessing global/pg_control. Maybe you need to apply permissions
recursively?

As 'pss-svc' user I can open, read and write to the pg_control file (
I took backup of this file first ).
I have exactly the same problem when I try to start progresql server
as Administrator instead of 'pss-svc' user

On 07/16/2012 07:54 PM, Petros Tsialiamanis wrote:

Sorry for the misunderstanding. When I said that I reproduced the
error in 9.1 version, I mean that I created the PGDATA with 9.1
postgresql server as 'local system' user and after that I tried to
start the postgresql server as 'pss-svc' user and I took the error
message which I sent with my previous mail. So there isn't any
incompatibility problem with PGDATA.

OK, that helps explain that. Thanks for following up with a current
version, then.

I have a Windows VM on this machine so I'll see if I can reproduce that
issue. I need a bit more information to do so. Specifically I need to
know how the user 'pss-svc' was created, what its group memberships are
and what its rights are ("can interact with desktop", "login as
service", etc).

As 'pss-svc' user I can open, read and write to the pg_control file (
I took backup of this file first ).

Open, read and write using what command(s) or programs?

Is there a UAC prompt?

Did you run the CACLS command you were given by John?

I have exactly the same problem when I try to start progresql server
as Administrator instead of 'pss-svc' user

If 'pss-svc' user is a member of Administrators or Local Admins, remove
the user from those groups. Pg is quite insistent about not being run as
admin. That shouldn't be the cause of these issues, as it's quite
explicit about it when that's the case, but it's a good idea anyway.

Personally I think Pg should let this up to the user, but that's the way
it is for now.

--
Craig Ringer