+ int ret;
+ struct agent_connection *conn;
+
+ assert(event == 1); /* not selecting for anything but R */
+
+ conn = find234(agent_connections, &fd, agent_connfind);
+ if (!conn) {
+ uxsel_del(fd);
+ return 1;
+ }
+
+ ret = read(fd, conn->retbuf+conn->retlen, conn->retsize-conn->retlen);
+ if (ret <= 0) {
+ if (conn->retbuf != conn->sizebuf) sfree(conn->retbuf);
+ conn->retbuf = NULL;
+ conn->retlen = 0;
+ goto done;
+ }
+ conn->retlen += ret;
+ if (conn->retsize == 4 && conn->retlen == 4) {
+ conn->retsize = toint(GET_32BIT(conn->retbuf) + 4);
+ if (conn->retsize <= 0) {
+ conn->retbuf = NULL;
+ conn->retlen = 0;
+ goto done;
+ }
+ assert(conn->retbuf == conn->sizebuf);
+ conn->retbuf = snewn(conn->retsize, char);
+ memcpy(conn->retbuf, conn->sizebuf, 4);
+ }
+
+ if (conn->retlen < conn->retsize)
+ return 0; /* more data to come */
+
+ done:
+ /*
+ * We have now completed the agent query. Do the callback, and
+ * clean up. (Of course we don't free retbuf, since ownership
+ * of that passes to the callback.)
+ */
+ conn->callback(conn->callback_ctx, conn->retbuf, conn->retlen);
+ uxsel_del(fd);
+ close(fd);
+ del234(agent_connections, conn);
+ sfree(conn);
+ return 0;
+}
+
+int agent_query(void *in, int inlen, void **out, int *outlen,
+ void (*callback)(void *, void *, int), void *callback_ctx)
+{
+ char *name;
+ int sock;
+ struct sockaddr_un addr;
+ int done;
+ struct agent_connection *conn;
+
+ name = getenv("SSH_AUTH_SOCK");
+ if (!name)
+ goto failure;
+
+ sock = socket(PF_UNIX, SOCK_STREAM, 0);
+ if (sock < 0) {
+ perror("socket(PF_UNIX)");
+ exit(1);
+ }
+
+ cloexec(sock);
+
+ addr.sun_family = AF_UNIX;
+ strncpy(addr.sun_path, name, sizeof(addr.sun_path));
+ if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+ close(sock);
+ goto failure;
+ }
+
+ for (done = 0; done < inlen ;) {
+ int ret = write(sock, (char *)in + done, inlen - done);
+ if (ret <= 0) {
+ close(sock);
+ goto failure;
+ }
+ done += ret;
+ }
+
+ if (!agent_connections)
+ agent_connections = newtree234(agent_conncmp);
+
+ conn = snew(struct agent_connection);
+ conn->fd = sock;
+ conn->retbuf = conn->sizebuf;
+ conn->retsize = 4;
+ conn->retlen = 0;
+ conn->callback = callback;
+ conn->callback_ctx = callback_ctx;
+ add234(agent_connections, conn);
+
+ uxsel_set(sock, 1, agent_select_result);
+ return 0;
+
+ failure:
+ *out = NULL;
+ *outlen = 0;
+ return 1;