1 files changed, 37 insertions, 0 deletions

diff --git a/kernel/itimer.c b/kernel/itimer.c
index 379be2f8c84c..a2dc375927d8 100644
--- a/kernel/itimer.c
+++ b/kernel/itimer.c
@@ -226,6 +226,43 @@ again:
         return 0;
 }
 
+/**
+ * alarm_setitimer - set alarm in seconds
+ *
+ * @seconds:    number of seconds until alarm
+ *              0 disables the alarm
+ *
+ * Returns the remaining time in seconds of a pending timer or 0 when
+ * the timer is not active.
+ *
+ * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
+ * negative timeval settings which would cause immediate expiry.
+ */
+unsigned int alarm_setitimer(unsigned int seconds)
+{
+        struct itimerval it_new, it_old;
+
+#if BITS_PER_LONG < 64
+        if (seconds > INT_MAX)
+                seconds = INT_MAX;
+#endif
+        it_new.it_value.tv_sec = seconds;
+        it_new.it_value.tv_usec = 0;
+        it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
+
+        do_setitimer(ITIMER_REAL, &it_new, &it_old);
+
+        /*
+         * We can't return 0 if we have an alarm pending ...  And we'd
+         * better return too much than too little anyway
+         */
+        if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) ||
+              it_old.it_value.tv_usec >= 500000)
+                it_old.it_value.tv_sec++;
+
+        return it_old.it_value.tv_sec;
+}
+
 asmlinkage long sys_setitimer(int which,
                               struct itimerval __user *value,
                               struct itimerval __user *ovalue)