Ah. I think something in the code is closing STDOUT (fd 1) before the
handler() is called. The socket that the driver then creates to connect
to the server will get fd 2, aka STDOUT, and thus be inherited by the
child. Or something like that.
Tim.
On Thu, Jan 07, 2010 at 10:03:06AM -0800, Jonathan Swartz wrote:
> Ok, take sendmail out of the equation. The bug will occur iff the
> program sends output to STDOUT (which sendmail was doing because of
> a warning).
>
> Here's a slightly simplified version.
>
> our ($dbh1, $dbh2);
>
> sub dbconnect {
> return DBI->connect( 'DBI:Sybase:...', '...', '...', {
> RaiseError => 1 } );
> }
>
> sub testdb {
> my ( $name, $dbh ) = @_;
> eval { $dbh->do("select 1") };
> print "$name - " . ($@ ? "error: $@" : "ok") . "\n";
> }
>
> sub handler {
> my ($r) = @_;
>
> # connect.pl contains one line: BEGIN { $Handler::dbh1 =
> Handler::dbconnect() }
> do "/home/jswartz/projects/unchained-transaction/connect.pl";
> $dbh2 = dbconnect();
> system(qq{perl -e 'print "hi"'});
> testdb("dbh1", $dbh1);
> testdb("dbh2", $dbh2);
>
> return 0;
> }
>
> This outputs
>
> dbh1 - ok
> dbh2 - error: DBD::Sybase::db do failed: OpenClient message:
> LAYER = (5) ORIGIN = (3) SEVERITY = (5) NUMBER = (6)
> Server SANDBOX5, database
> Message String: ct_results(): network packet layer: internal net
> library error: Net-Library operation terminated due to disco\
> nnect
> OpenClient message: LAYER = (1) ORIGIN = (1) SEVERITY = (1)
> NUMBER = (50)
> Server SANDBOX5, database
> Message String: ct_cmd_drop(): user api layer: external error:
> The connection has been marked dead.
>
> However, if I replace the system with
>
> system(qq{perl -e ''});
> or
> system(qq{perl -e 'print "hi"' > /dev/null});
>
> then it outputs
>
> dbh1 - ok
> dbh2 - ok
>
> On Jan 7, 2010, at 2:20 AM, Tim Bunce wrote:
>
> >On Wed, Jan 06, 2010 at 04:08:17PM -0800, Jonathan Swartz wrote:
> >>Thanks for your help...this bug has me feeling very isolated...
> >>
> >>>>Just about everything here is necessary to generate the bug. In
> >>>>particular, I cannot generate the bug...
> >>>>* If I move the code from connect.pl into the handler, even as a
> >>>>string eval
> >>>>* If I remove the "BEGIN" from connect.pl
> >>>>* If I replace sendmail with another program
> >>>
> >>>That's the most interesting one to me. Try replacing it with a perl
> >>>script that reports what open file descriptors have been inherited.
> >>
> >>Ok. What's the easiest way to do that? :) Sorry, probably dumb
> >>question, but never did this before and scanning perlipc and
> >>perlopentut and google didn't yield anything obvious.
> >
> >I had to rummage around a bit, but this seems to work:
> >
> > $ perl -e 'open(FH, ">&=$_") and printf "$_\n" for 0..100'
> > 0
> > 1
> > 2
> >
> > $ perl -e 'open(FH, ">&=$_") and printf "$_\n" for 0..100' 42<&1
> > 0
> > 1
> > 2
> > 42
> >
> >(Using >&= or <&= doesn't seem to matter for this simple case.)
> >
> >Tim.
>
