FreeBSD doesn't have the simple pidfile(3), so craft it using FreeBSD's

primitives.

libexec/lukemftpd/nbsd_pidfile.h

@@ -0,0 +1,30 @@
+/* $FreeBSD$ */
+
+#include <sys/stdint.h>
+#include <sysexits.h>
+
+static int
+pidfile(const char *basename)
+{
+	struct pidfh *pfh;
+	pid_t otherpid, childpid;
+
+	if (basename != NULL) {
+		errx(EX_USAGE, "Need to impliment NetBSD semantics.");
+	}
+
+	pfh = pidfile_open(basename, 0644, &otherpid);
+	if (pfh == NULL) {
+		if (errno == EEXIST) {
+			errx(EXIT_FAILURE, "Daemon already running, pid: %jd.",
+			    (intmax_t)otherpid);
+		}
+		/* If we cannot create pidfile from other reasons, only warn. */
+		warn("Cannot open or create pidfile");
+		return -1;
+	}
+
+	pidfile_write(pfh);
+	pidfile_close(pfh);
+	return 0;
+}