From 152194fe9c3f03232b9c0d0264793a7fa4af82f8 Mon Sep 17 00:00:00 2001 From: Deepa Dinamani Date: Sun, 7 Jan 2018 17:44:42 -0800 Subject: Input: extend usable life of event timestamps to 2106 on 32 bit systems The input events use struct timeval to store event time, unfortunately this structure is not y2038 safe and is being replaced in kernel with y2038 safe structures. Because of ABI concerns we can not change the size or the layout of structure input_event, so we opt to re-interpreting the 'seconds' part of timestamp as an unsigned value, effectively doubling the range of values, to year 2106. Newer glibc that has support for 32 bit applications to use 64 bit time_t supplies __USE_TIME_BITS64 define [1], that we can use to present the userspace with updated input_event layout. The updated layout will cause the compile time breakage, alerting applications and distributions maintainers to the issue. Existing 32 binaries will continue working without any changes until 2038. Ultimately userspace applications should switch to using monotonic or boot time clocks, as realtime clock is not very well suited for input event timestamps as it can go backwards (see a80b83b7b8 "Input: evdev - add CLOCK_BOOTTIME support" by by John Stultz). With monotonic clock the practical range of reported times will always fit into the pair of 32 bit values, as we do not expect any system to stay up for a hundred years without a single reboot. [1] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign Suggested-by: Arnd Bergmann Signed-off-by: Deepa Dinamani Acked-by: Peter Hutterer Patchwork-Id: 10148083 Signed-off-by: Dmitry Torokhov --- drivers/input/input-compat.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/input/input-compat.c') diff --git a/drivers/input/input-compat.c b/drivers/input/input-compat.c index 2186f71c9fe5..fda8d6d2a268 100644 --- a/drivers/input/input-compat.c +++ b/drivers/input/input-compat.c @@ -24,8 +24,8 @@ int input_event_from_user(const char __user *buffer, sizeof(struct input_event_compat))) return -EFAULT; - event->time.tv_sec = compat_event.time.tv_sec; - event->time.tv_usec = compat_event.time.tv_usec; + event->input_event_sec = compat_event.sec; + event->input_event_usec = compat_event.usec; event->type = compat_event.type; event->code = compat_event.code; event->value = compat_event.value; @@ -44,8 +44,8 @@ int input_event_to_user(char __user *buffer, if (in_compat_syscall() && !COMPAT_USE_64BIT_TIME) { struct input_event_compat compat_event; - compat_event.time.tv_sec = event->time.tv_sec; - compat_event.time.tv_usec = event->time.tv_usec; + compat_event.sec = event->input_event_sec; + compat_event.usec = event->input_event_usec; compat_event.type = event->type; compat_event.code = event->code; compat_event.value = event->value; -- cgit v1.2.3-59-g8ed1b