* * * * *
I must have forgotten my cardboard programmer that day …
D'oh!
Smirk called today, saying a customer had a problem sending mail with one of
their PHP scripts. The server in question was running my PHP/sendmail wrapper
[1] and the testing that Smirk did showed that the PHP mail [2]() function
wasn't returning anything! Funny, for a function that supposedly returns a
bool …
With Wlofie [3] playing the part of cardboard programmer [4], I did some
testing, found that indeed, there was a problem—at first, it looked like the
system was terminating the program with random signals. One time it would
terminate with a SIGXFSZ, then with SIGTTIN, then with SIGWINCH!
I then stared at the code until I bled …
> else /* parent process */
> {
> pid_t cstat;
> int status;
>
> cstat = waitpid(child,&status,0);
>
> if (WIFEXITED(cstat))
> rc = WEXITSTATUS(cstat);
> else
> rc = EXIT_FAILURE;
>
> unlink(tmpfile); /* make sure we clean up after ourselves */
> exit(rc);
> }
>
It was then i saw my mistake—I was checking the wrong variable!
Sigh.
The type of mistake a statically typed language should catch. And before you
say “unit testing” my tests were basically “did the email go through? Yup?
Then it works”—the thought to check the return code of my program as a whole
didn't occur to me (hey, the email got through, right? that meant that it
worked).
I changed WIFEXITED(cstat) to WIFEXITED(status) and WEXITSTATUS(cstat) to
WEXITSTATUS(status) and it worked.
I also checked PHP, and for the life of me, I can't figure out why it was
returning undef, but then again, PHP is the scripting language du jour so it
may be I didn't check the precise version we're running.
[1]
gopher://gopher.conman.org/0Phlog:2008/02/13.1
[2]
http://www.php.net/manual/en/function.mail.php
[3]
http://wlofie.dyndns.org/
[4]
http://c2.com/cgi/wiki?CardboardProgrammer
Email author at
[email protected]
