basically none of these build
diff --git a/src/libauth/auth_respond.c b/src/libauth/auth_respond.c
new file mode 100644
index 0000000..910f06b
--- /dev/null
+++ b/src/libauth/auth_respond.c
@@ -0,0 +1,73 @@
+#include <u.h>
+#include <libc.h>
+#include <auth.h>
+#include <authsrv.h>
+#include "authlocal.h"
+
+enum {
+ ARgiveup = 100,
+};
+
+static int
+dorpc(AuthRpc *rpc, char *verb, char *val, int len, AuthGetkey *getkey)
+{
+ int ret;
+
+ for(;;){
+ if((ret = auth_rpc(rpc, verb, val, len)) != ARneedkey && ret != ARbadkey)
+ return ret;
+ if(getkey == nil)
+ return ARgiveup; /* don't know how */
+ if((*getkey)(rpc->arg) < 0)
+ return ARgiveup; /* user punted */
+ }
+}
+
+int
+auth_respond(void *chal, uint nchal, char *user, uint nuser, void *resp, uint nresp, AuthGetkey *getkey, char *fmt, ...)
+{
+ char *p, *s;
+ va_list arg;
+ int afd;
+ AuthRpc *rpc;
+ Attr *a;
+
+ if((afd = open("/mnt/factotum/rpc", ORDWR)) < 0)
+ return -1;
+
+ if((rpc = auth_allocrpc(afd)) == nil){
+ close(afd);
+ return -1;
+ }
+
+ quotefmtinstall(); /* just in case */
+ va_start(arg, fmt);
+ p = vsmprint(fmt, arg);
+ va_end(arg);
+
+ if(p==nil
+ || dorpc(rpc, "start", p, strlen(p), getkey) != ARok
+ || dorpc(rpc, "write", chal, nchal, getkey) != ARok
+ || dorpc(rpc, "read", nil, 0, getkey) != ARok){
+ free(p);
+ close(afd);
+ auth_freerpc(rpc);
+ return -1;
+ }
+ free(p);
+
+ if(rpc->narg < nresp)
+ nresp = rpc->narg;
+ memmove(resp, rpc->arg, nresp);
+
+ if((a = auth_attr(rpc)) != nil
+ && (s = _strfindattr(a, "user")) != nil && strlen(s) < nuser)
+ strcpy(user, s);
+ else if(nuser > 0)
+ user[0] = '\0';
+
+ _freeattr(a);
+ close(afd);
+ auth_freerpc(rpc);
+ return nresp;
+}
