Re: [HACKERS] Win32 WEXITSTATUS too - Mailing list pgsql-patches

Magnus Hagander wrote:
> On Tue, Jan 23, 2007 at 10:26:29AM -0500, Bruce Momjian wrote:
> > Magnus Hagander wrote:
> > > On Tue, Jan 23, 2007 at 10:11:58AM -0500, Bruce Momjian wrote:
> > > > Magnus Hagander wrote:
> > > > > > > I think that's incorrect information to the user :-(
> > > > > > > If the child terminates with exit(1), we will then say "child process
> > > > > > > was terminated by exception 1. This seems to be a bug", which is clearly
> > > > > > > not true.
> > > > > > >
> > > > > > > Unless you know a sure way of determining if the exitcode is a normal
> > > > > > > exitcode or an exception code.
> > > > > >
> > > > > > Current CVS believes values >= 0x100 are non-exit() terminations.
> > > > >
> > > > > Why does it do that :-) That's clearly wrong. There are plenty of
> > > > > exitcodes > 0x100 that aren't exceptions.
> > > >
> > > > Please read include/port/win32.h comment section on this and then reply.
> > > > We only care about non-exit() exits.
> > >
> > > Right. I did.  and exit() can return a lot of error codes > 0x100. For example,
> > > a simple:
> > > int main(int argc, char *argv) {
> > >    exit(12345);
> > > }
> >
> > Yes, I know it works, but it can return 0xc0000005 too.  I think we have
> > to be reasonable and say >= 0x100 is probably the OS.
>
> Depends on what you mean with OS.
> There are a *lot* of tools that will return exitcodes >0x100 that are
> part of the OS. As a relevant example, Windows installer will return
> exitcode 3010 means "needs to reboot but didn't reboot". MSI is a part
> of the OS, but it's not kernel... Same thing for things like the service
> control manager (trying to operate on a service that has been removed
> gives you error 1060).

Is there a portable way to get the _exception_ value from system(),
rather than the error code?  We could go with just > 0xC0000000 values
as exceptions.  (This is clearly showing the mess that is the WIN32
API.)

> > > would break that assumption. (And yes, it works)
> > > exit() takes a 32-bit signed integer, and that's what comes out to the
> > > calling program (verified both with console and standalone program)
> > >
> > > The MSDN link referes to the DDK which has to do with driver
> > > development, not userspace. AFAIK, that list is not relevant here, and
> > > I've seen no actual reference so far that it should be used to look up
> > > exit codes.
> > >
> > > Now, if we're only caring about exit() from *postgresqls own processes*,
> > > that might hold true. In which case I withdraw that objection as long as
> > > the comment i updated to reflect this ;-) But if we're talking about
> > > exit() in general of any process, then it's simply wrong.
> >
> > Right, that code is only used by the backend and tools.
>
> We should be very clear about that in our comment then, and the current
> comment is not. And the part referring to the DDK should just be
> removed, because it's simply incorrect.
>
> For example, don't we call cmd for PITR scripts? If we're using any of
> these macros on the return value from there we are *NOT* certain of what
> it will be, and then need to document that as a requirement on those
> scripts.

The major place we use it is for backend termination checking, and we
know the return values there.  The other place is for the return value
of pipe().

--
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

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