mb <mb@???> wrote:
> At 16:53 +0100 Raviraj Jeyanolipavan wrote:
>
> >I am trying to use local_scan.c from L001 on the web site together
> >with McAfee's uvscan to virus check emails but on a test email I
> >keep getting "UVSCAN_ERROR: couldn't wait for child".
>
> Could you please verify it still fails please with my new script (don't
> think it made it into the 4.20 docs)?
>
> http://www.dcs.qmul.ac.uk/~mb/local_scan/local_scan.c
>
> >A small test program simulating the local_scan.c code doesn't get
> >these errors and I am unable to work out why this error occurs. This
> >is running on Solaris 8 on a SPARC platform.
>
> I've not tested it on this platform. Perhaps waitpid behaves differently?
> (Or more likely I've got a variable type wrong.. and it happens to work
> on Linux.)
This sounds like a problem I had where you couldn't wait on a
child process with SIGCHLD ignored, which is the case when you
enter local_scan (on my 4.12).
I set SIGCHLD handling to SIG_DFL on entry (remembering the original
setting), and reset it to the remembered value on exit.
I stole some code from elsewhere in the source. I also set SIGPIPE
to SIG_IGN to capture write errors to the pipe.
On entry to local_scan()
/*
* Setup signal handling
* - Set child signal handling back to the default.
* Normal mode (in exim) is SIG_IGN which causes wait to wait
* for processes but it always returns -1 and no status. This
* breaks trying to get a exit code from our scanner sub-process
* - Set pipe signal handling to SIG_IGN so we get write errors
* rather than signals if our sub-process fails
*/
void (*oldPipeSig)(); /* Old pipe signal value */
#ifdef SA_NOCLDWAIT
struct sigaction act,oldChldSig;
act.sa_handler = SIG_DFL;
sigemptyset(&(act.sa_mask));
act.sa_flags = 0;
sigaction(SIGCHLD, &act, &oldChldSig);
#else
void (*oldChldSig)(); /* Old pipe signal value */
oldChldSig = signal(SIGCHLD, SIG_DFL);
#endif
oldPipeSig = signal(SIGPIPE,SIG_IGN);
On exit (remember to funnel all exit paths through this)
#ifdef SA_NOCLDWAIT
sigaction(SIGCHLD, &oldChldSig, NULL);
#else
(void)signal(SIGPIPE,oldChldSig);
#endif
(void)signal(SIGPIPE,oldPipeSig);
--
Do two rights make | Kevin Smith, ShadeTree Software, Philadelphia, PA, USA
a libertarian | 001-215-487-3811 shady,com,kevin
