add missing /sys/src/cmd/auth/lib/private.c

sys/src/cmd/auth/lib/private.c

@@ -0,0 +1,28 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include <authsrv.h>
+#include "authcmdlib.h"
+
+static char *pmsg = "Warning! %s can't protect itself from debugging: %r\n";
+static char *smsg = "Warning! %s can't turn off swapping: %r\n";
+
+/* don't allow other processes to debug us and steal keys */
+void
+private(void)
+{
+	int fd;
+	char buf[64];
+
+	snprint(buf, sizeof(buf), "#p/%d/ctl", getpid());
+	fd = open(buf, OWRITE);
+	if(fd < 0){
+		fprint(2, pmsg, argv0);
+		return;
+	}
+	if(fprint(fd, "private") < 0)
+		fprint(2, pmsg, argv0);
+	if(fprint(fd, "noswap") < 0)
+		fprint(2, smsg, argv0);
+	close(fd);
+}