media: v4l2-core: fix VIDIOC_DQEVENT for time64 ABI

The v4l2_event structure contains a 'struct timespec' member that is
defined by the user space C library, creating an ABI incompatibility
when that gets updated to a 64-bit time_t.

While passing a 32-bit time_t here would be sufficient for CLOCK_MONOTONIC
timestamps, simply redefining the structure to use the kernel's
__kernel_old_timespec would not work for any library that uses a copy
of the linux/videodev2.h header file rather than including the copy from
the latest kernel headers.

This means the kernel has to be changed to handle both versions of the
structure layout on a 32-bit architecture. The easiest way to do this
is during the copy from/to user space.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Arnd Bergmann 2019-12-16 15:15:03 +01:00 committed by Mauro Carvalho Chehab
parent c8ef1a6076
commit 1a6c0b36dd
5 changed files with 86 additions and 3 deletions

View File

@ -27,6 +27,7 @@ static unsigned sev_pos(const struct v4l2_subscribed_event *sev, unsigned idx)
static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)
{
struct v4l2_kevent *kev;
struct timespec64 ts;
unsigned long flags;
spin_lock_irqsave(&fh->vdev->fh_lock, flags);
@ -44,7 +45,9 @@ static int __v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event)
kev->event.pending = fh->navailable;
*event = kev->event;
event->timestamp = ns_to_timespec(kev->ts);
ts = ns_to_timespec64(kev->ts);
event->timestamp.tv_sec = ts.tv_sec;
event->timestamp.tv_nsec = ts.tv_nsec;
kev->sev->first = sev_pos(kev->sev, 1);
kev->sev->in_use--;

View File

@ -821,7 +821,7 @@ static void v4l_print_event(const void *arg, bool write_only)
const struct v4l2_event *p = arg;
const struct v4l2_event_ctrl *c;
pr_cont("type=0x%x, pending=%u, sequence=%u, id=%u, timestamp=%lu.%9.9lu\n",
pr_cont("type=0x%x, pending=%u, sequence=%u, id=%u, timestamp=%llu.%9.9llu\n",
p->type, p->pending, p->sequence, p->id,
p->timestamp.tv_sec, p->timestamp.tv_nsec);
switch (p->type) {
@ -3025,6 +3025,13 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
static unsigned int video_translate_cmd(unsigned int cmd)
{
switch (cmd) {
#ifdef CONFIG_COMPAT_32BIT_TIME
case VIDIOC_DQEVENT_TIME32:
return VIDIOC_DQEVENT;
#endif
}
return cmd;
}
@ -3074,6 +3081,26 @@ static int video_put_user(void __user *arg, void *parg, unsigned int cmd)
return 0;
switch (cmd) {
#ifdef CONFIG_COMPAT_32BIT_TIME
case VIDIOC_DQEVENT_TIME32: {
struct v4l2_event *ev = parg;
struct v4l2_event_time32 ev32 = {
.type = ev->type,
.pending = ev->pending,
.sequence = ev->sequence,
.timestamp.tv_sec = ev->timestamp.tv_sec,
.timestamp.tv_nsec = ev->timestamp.tv_nsec,
.id = ev->id,
};
memcpy(&ev32.u, &ev->u, sizeof(ev->u));
memcpy(&ev32.reserved, &ev->reserved, sizeof(ev->reserved));
if (copy_to_user(arg, &ev32, sizeof(ev32)))
return -EFAULT;
break;
}
#endif
default:
/* Copy results into user buffer */
if (copy_to_user(arg, parg, _IOC_SIZE(cmd)))

View File

@ -331,8 +331,8 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
struct v4l2_fh *vfh = file->private_data;
#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
struct v4l2_subdev_fh *subdev_fh = to_v4l2_subdev_fh(vfh);
int rval;
#endif
int rval;
switch (cmd) {
case VIDIOC_QUERYCTRL:
@ -392,6 +392,30 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
return v4l2_event_dequeue(vfh, arg, file->f_flags & O_NONBLOCK);
case VIDIOC_DQEVENT_TIME32: {
struct v4l2_event_time32 *ev32 = arg;
struct v4l2_event ev;
if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS))
return -ENOIOCTLCMD;
rval = v4l2_event_dequeue(vfh, &ev, file->f_flags & O_NONBLOCK);
*ev32 = (struct v4l2_event_time32) {
.type = ev.type,
.pending = ev.pending,
.sequence = ev.sequence,
.timestamp.tv_sec = ev.timestamp.tv_sec,
.timestamp.tv_nsec = ev.timestamp.tv_nsec,
.id = ev.id,
};
memcpy(&ev32->u, &ev.u, sizeof(ev.u));
memcpy(&ev32->reserved, &ev.reserved, sizeof(ev.reserved));
return rval;
}
case VIDIOC_SUBSCRIBE_EVENT:
return v4l2_subdev_call(sd, core, subscribe_event, vfh, arg);

View File

@ -724,4 +724,29 @@ long int video_usercopy(struct file *file, unsigned int cmd,
long int video_ioctl2(struct file *file,
unsigned int cmd, unsigned long int arg);
/*
* The user space interpretation of the 'v4l2_event' differs
* based on the 'time_t' definition on 32-bit architectures, so
* the kernel has to handle both.
* This is the old version for 32-bit architectures.
*/
struct v4l2_event_time32 {
__u32 type;
union {
struct v4l2_event_vsync vsync;
struct v4l2_event_ctrl ctrl;
struct v4l2_event_frame_sync frame_sync;
struct v4l2_event_src_change src_change;
struct v4l2_event_motion_det motion_det;
__u8 data[64];
} u;
__u32 pending;
__u32 sequence;
struct old_timespec32 timestamp;
__u32 id;
__u32 reserved[8];
};
#define VIDIOC_DQEVENT_TIME32 _IOR('V', 89, struct v4l2_event_time32)
#endif /* _V4L2_IOCTL_H */

View File

@ -2341,7 +2341,11 @@ struct v4l2_event {
} u;
__u32 pending;
__u32 sequence;
#ifdef __KERNEL__
struct __kernel_timespec timestamp;
#else
struct timespec timestamp;
#endif
__u32 id;
__u32 reserved[8];
};