extsearchidx: improve missing machine-id fallback

It's likely most GNU/Linux systems have /etc/machine-id these
days, so anything missing it is likely a *BSD, most of which
support and favor "sysctl -n kern.hostid".  We'll also support
"ghostid" since GNU utils are commonly prefixed with 'g' on
non-GNU platforms.

In any case, we'll suppress stderr from missing commands and
fall back to hard coding an $OSNAME-based identifier as a last
resort and hope the hostname is unique.

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/PublicInbox/ExtSearchIdx.pm b/lib/PublicInbox/ExtSearchIdx.pm
index c6fb398b..b82d0546 100644
--- a/lib/PublicInbox/ExtSearchIdx.pm
+++ b/lib/PublicInbox/ExtSearchIdx.pm
@@ -530,8 +530,10 @@ sub host_ident () {
         state $retval = hostname . '-' . do {
                 my $m; # machine-id(5) is systemd
                 if (open(my $fh, '<', '/etc/machine-id')) { $m = <$fh> }
-                # hostid(1) is in GNU coreutils, kern.hostid is FreeBSD
-                chomp($m ||= `hostid` || `sysctl -n kern.hostid`);
+                # (g)hostid(1) is in GNU coreutils, kern.hostid is most BSDs
+                chomp($m ||= `{ sysctl -n kern.hostid ||
+                                hostid || ghostid; } 2>/dev/null`
+                        || "no-machine-id-or-hostid-on-$^O");
                 $m;
         };
 }