Changes to log.go. All files

log.go

@@ -164,6 +164,18 @@ func openLogFile(path string) (*os.File, error) { 	return os.OpenFile(path, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0o600) } +// stderrIsJournal reports whether stderr is a journal stream that systemd+// connected, as it does for a unit's process, by JOURNAL_STREAM, its+// device and inode. A line logged then needs no copy on stderr, which+// would show it twice in the journal.+func stderrIsJournal() bool {+	var st syscall.Stat_t+	if os.Getenv("JOURNAL_STREAM") == "" || syscall.Fstat(2, &st) != nil {+		return false+	}+	return os.Getenv("JOURNAL_STREAM") == fmt.Sprintf("%d:%d", st.Dev, st.Ino)+}+ // logSink is where a detached server's stderr goes: a journal stream, or // the fallback file. A panic writes there, past every logger. It returns // nil when neither opens, and stderr then goes nowhere, as before.