Some pseudo code: 
open pipe from ps aux, perhaps after grepping for sendmail
while(<PIPE>) {
  my ($owner, $pid,
      undef, undef, undef, undef, undef, undef, undef, undef, # Throw 
+eight values away
      $command_withIP) = split(' ', $_, 11);
Do stuff
}

[download]

Update: What c suggests is a good path to take, especially since the ps table is rather transitory. You won't be sure of having a pid match. If the log doesn't have the IP address, I'm sure that can be set via sendmail.cf. You may also want to look into /etc/mail for some more clues.

Update2: thank you bbfu

In reply to Re: ps aux and perl by lemming
in thread ps aux and perl by Jerry

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