Re: 9.2 beta2 - pg_ctl crashes on Win32 when neither PGDATA nor -D specified

On 13 June 2012 00:54, Amit Kapila <amit(dot)kapila(at)huawei(dot)com> wrote:
>>> I note that "postgres -C data_directory" will refuse to run on the
>>> command line because I've got admin privileges in Windows, and that
>>> pg_ctl normally starts postgres.exe using CreateRestrictedProcess.
>>> But it does not do so for the popen call in adjust_data_dir.
>
>> if that actually is a third bug, as seems likely, somebody with access
>> to a windows environment will need to deal with it.
>
> I am able to reproduce this problem, "that pg_ctl throws error for
> administrative user in the mentioned code path".
>
> One solution to this problem is that pg_ctl invoke itself in a restricted
> mode, similar to initdb.
> This will allow popen call to be successful in pg_ctl code path.

Perhaps an alternative solution is to get postgres to handle -C calls
without checking if it's running as root. The command does not do
much more than read the config file, print a value from it, and exit.

Unfortunately in src/backend/main/main.c it only does a cursory check
for --help and --version. So it would need to become a little more
complicated to scan for -C options at that stage. It's not too much
if you can assume -C always appears first like the other special
options detected in that file.

But you might not want to make an exception for -C. And I realise the
check is a security feature, and it's best to err on the side of
defensive programming and maintainability.

Edmund.