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.
state $retval = hostname . '-' . do {
my $m; # machine-id(5) is systemd
if (open(my $fh, '<', '/etc/machine-id')) { $m = <$fh> }
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");