From abfdff44bc38e9e2ef7929f633fb8462632299d4 Mon Sep 17 00:00:00 2001
From: Alexandre Belloni <alexandre.belloni@bootlin.com>
Date: Tue, 5 Jun 2018 23:09:14 +0200
Subject: [PATCH] rtc: ensure rtc_set_alarm fails when alarms are not supported
Git-commit: abfdff44bc38e9e2ef7929f633fb8462632299d4
Patch-mainline: v4.18-rc1
References: bsc#1051510
When using RTC_ALM_SET or RTC_WKALM_SET with rtc_wkalrm.enabled not set,
rtc_timer_enqueue() is not called and rtc_set_alarm() may succeed but the
subsequent RTC_AIE_ON ioctl will fail. RTC_ALM_READ would also fail in that
case.
Ensure rtc_set_alarm() fails when alarms are not supported to avoid letting
programs think the alarms are working for a particular RTC when they are
not.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/rtc/interface.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 7cbdc9228dd5..6d4012dd6922 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -441,6 +441,11 @@ int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
int err;
+ if (!rtc->ops)
+ return -ENODEV;
+ else if (!rtc->ops->set_alarm)
+ return -EINVAL;
+
err = rtc_valid_tm(&alarm->time);
if (err != 0)
return err;
--
2.18.0