treewide: avoid getpid() for OnDestroy checks

getpid() isn't cached by glibc nowadays and system calls are
more expensive due to CPU vulnerability mitigations.  To
ensure we switch to the new semantics properly, introduce
a new `on_destroy' function to simplify callers.
Furthermore, most OnDestroy correctness is often tied to the
process which creates it, so make the new API default to
guarded against running in subprocesses.

For cases which require running in all children, a new
PublicInbox::OnDestroy::all call is provided.

1 files changed, 5 insertions, 4 deletions

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index 8bc8cfb7..a6fec954 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -32,9 +32,9 @@ use PublicInbox::Syscall qw(%SIGNUM
         EPOLLIN EPOLLOUT EPOLLONESHOT EPOLLEXCLUSIVE);
 use PublicInbox::Tmpfile;
 use PublicInbox::Select;
+use PublicInbox::OnDestroy;
 use Errno qw(EAGAIN EINVAL ECHILD);
 use Carp qw(carp croak);
-use autodie qw(fork);
 our @EXPORT_OK = qw(now msg_more awaitpid add_timer add_uniq_timer);
 
 my $nextq; # queue for next_tick
@@ -679,12 +679,13 @@ sub awaitpid {
         }
 }
 
-sub do_fork () {
+# for persistent child process
+sub fork_persist () {
         my $seed = rand(0xffffffff);
-        my $pid = fork;
+        my $pid = PublicInbox::OnDestroy::fork_tmp;
         if ($pid == 0) {
                 srand($seed);
-                eval { Net::SSLeay::randomize() };
+                eval { Net::SSLeay::randomize() }; # may not be loaded
                 Reset();
         }
         $pid;