signal/timer/event: timerfd compat code

This patch implements the necessary compat code for the timerfd system call.
Signed-off-by: NDavide Libenzi <davidel@xmailserver.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/compat.c

@@ -2225,3 +2225,26 @@ asmlinkage long compat_sys_signalfd(int ufd,
 
 #endif /* CONFIG_SIGNALFD */
 
+#ifdef CONFIG_TIMERFD
+
+asmlinkage long compat_sys_timerfd(int ufd, int clockid, int flags,
+				   const struct compat_itimerspec __user *utmr)
+{
+	long res;
+	struct itimerspec t;
+	struct itimerspec __user *ut;
+
+	res = -EFAULT;
+	if (get_compat_itimerspec(&t, utmr))
+		goto err_exit;
+	ut = compat_alloc_user_space(sizeof(*ut));
+	if (copy_to_user(ut, &t, sizeof(t)) )
+		goto err_exit;
+
+	res = sys_timerfd(ufd, clockid, flags, ut);
+err_exit:
+	return res;
+}
+
+#endif /* CONFIG_TIMERFD */
+

include/linux/compat.h

@@ -225,6 +225,11 @@ static inline int compat_timespec_compare(struct compat_timespec *lhs,
 	return lhs->tv_nsec - rhs->tv_nsec;
 }
 
+extern int get_compat_itimerspec(struct itimerspec *dst,
+				 const struct compat_itimerspec __user *src);
+extern int put_compat_itimerspec(struct compat_itimerspec __user *dst,
+				 const struct itimerspec *src);
+
 asmlinkage long compat_sys_adjtimex(struct compat_timex __user *utp);
 
 extern int compat_printk(const char *fmt, ...);

kernel/compat.c

@@ -475,8 +475,8 @@ asmlinkage long compat_sys_sched_getaffinity(compat_pid_t pid, unsigned int len,
 	return min_length;
 }
 
-static int get_compat_itimerspec(struct itimerspec *dst, 
-				 struct compat_itimerspec __user *src)
+int get_compat_itimerspec(struct itimerspec *dst,
+			  const struct compat_itimerspec __user *src)
 { 
 	if (get_compat_timespec(&dst->it_interval, &src->it_interval) ||
 	    get_compat_timespec(&dst->it_value, &src->it_value))
@@ -484,8 +484,8 @@ static int get_compat_itimerspec(struct itimerspec *dst,
 	return 0;
 } 
 
-static int put_compat_itimerspec(struct compat_itimerspec __user *dst, 
-				 struct itimerspec *src)
+int put_compat_itimerspec(struct compat_itimerspec __user *dst,
+			  const struct itimerspec *src)
 { 
 	if (put_compat_timespec(&src->it_interval, &dst->it_interval) ||
 	    put_compat_timespec(&src->it_value, &dst->it_value))