diff --git a/rdo.c b/rdo.c
index 26f2bdc..1b463c3 100644
--- a/rdo.c
+++ b/rdo.c
@@ -68,7 +68,7 @@ void runprog(char** program_argv) {
 
 int main(int argc, char** argv) {
     char groupname[64], wrong_pw_sleep[64], session_ttl[64], password[128];
-    unsigned int sleep_us, tries, ts_ttl;
+    int sleep_us, tries, ts_ttl;
 
     int read_pw_from_stdin = 0;
     if (argc > 1)
diff --git a/sessions.h b/sessions.h
index 5f2d0d0..63908cf 100644
--- a/sessions.h
+++ b/sessions.h
@@ -4,6 +4,7 @@
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/ioctl.h>
 #include <fcntl.h>
 #include <time.h>
 
@@ -77,12 +78,19 @@ int ensuredir() {
     return 0;
 }
 
-void setsession(int pid, unsigned int ts_ttl, int ruid) {
+void setsession(int pid, int ts_ttl, int ruid) {
+    if (ts_ttl <= 0)
+        return;
+
+#ifdef TIOCSETVERAUTH
+    int ttyfd = open("/dev/tty", O_RDWR);
+    ioctl(ttyfd, TIOCSETVERAUTH, &ts_ttl);
+    close(ttyfd);
+
+#else
     unsigned long long startts;
     char path[1024], ts_str[32];
 
-    if (ts_ttl == 0)
-        return;
 
     if (ensuredir() < 0 || getpstartts(pid, &startts) < 0)
         return;
@@ -104,17 +112,25 @@ void setsession(int pid, unsigned int ts_ttl, int ruid) {
     }
 
     close(fd);
+#endif
 
     return;
 }
 
-int getsession(int pid, unsigned int ts_ttl, int ruid) {
+int getsession(int pid, int ts_ttl, int ruid) {
+    if (ts_ttl <= 0)
+        return -1;
+
+#ifdef TIOCCHKVERAUTH
+    int ttyfd = open("/dev/tty", O_RDWR);
+    int ret = ioctl(ttyfd, TIOCCHKVERAUTH);
+    close(ttyfd);
+    return ret;
+
+#else
     unsigned long long startts, current;
     char path[1024], ts_str[32];
 
-    if (ts_ttl == 0)
-        return -1;
-
     if (ensuredir() < 0 || getpstartts(pid, &startts) < 0)
         return -1;
 
@@ -138,10 +154,11 @@ int getsession(int pid, unsigned int ts_ttl, int ruid) {
     startts = strtoull(ts_str, NULL, 10);
     current = time(NULL);
 
-    if (current - startts > ts_ttl) {
+    if (current - startts > (unsigned int)ts_ttl) {
         unlink(path);
         return -1;
     }
 
     return 0;
+#endif
 }