[PATCH v3 1/2] ppdev: convert to y2038 safe

[Bamvor Jian Zhang]

The y2038 issue for ppdev is changes of timeval in the ioctl
(PPSETTIME and PPGETTIME). The size of struct timeval changes from
8bytes to 16bytes due to the changes of time_t. It lead to the
changes of the command of ioctl, e.g. for PPGETTIME, We have:

on 32-bit (old): 0x80087095
on 32-bit (new): 0x80107095
on 64-bit      : 0x80107095

This patch define these two ioctl commands to support the 32bit
and 64bit time_t application at the same time. And, introduce
pp_set_timeout to remove some duplicated code.

Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@xxxxxxxxxx>
Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
Tested-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
---
 drivers/char/ppdev.c | 75 ++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 55 insertions(+), 20 deletions(-)

diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index ae0b42b..c03d998 100644
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -98,6 +98,13 @@ struct pp_struct {
 #define ROUND_UP(x,y) (((x)+(y)-1)/(y))
 
 static DEFINE_MUTEX(pp_do_mutex);
+
+/* define fixed sized ioctl cmd for y2038 migration */
+#define PPGETTIME32	_IOR(PP_IOCTL, 0x95, s32[2])
+#define PPSETTIME32	_IOW(PP_IOCTL, 0x96, s32[2])
+#define PPGETTIME64	_IOR(PP_IOCTL, 0x95, s64[2])
+#define PPSETTIME64	_IOW(PP_IOCTL, 0x96, s64[2])
+
 static inline void pp_enable_irq (struct pp_struct *pp)
 {
 	struct parport *port = pp->pdev->port;
@@ -322,6 +329,22 @@ static enum ieee1284_phase init_phase (int mode)
 	return IEEE1284_PH_FWD_IDLE;
 }
 
+static int pp_set_timeout(struct pardevice *pdev, long tv_sec, int tv_usec)
+{
+	long to_jiffies;
+
+	if ((tv_sec < 0) || (tv_usec < 0))
+		return -EINVAL;
+
+	to_jiffies = usecs_to_jiffies(tv_usec);
+	to_jiffies += tv_sec * HZ;
+	if (to_jiffies <= 0)
+		return -EINVAL;
+
+	pdev->timeout = to_jiffies;
+	return 0;
+}
+
 static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	unsigned int minor = iminor(file_inode(file));
@@ -495,9 +518,10 @@ static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		unsigned char reg;
 		unsigned char mask;
 		int mode;
+		s32 time32[2];
+		s64 time64[2];
+		struct timespec64 ts;
 		int ret;
-		struct timeval par_timeout;
-		long to_jiffies;
 
 	case PPRSTATUS:
 		reg = parport_read_status (port);
@@ -592,29 +616,40 @@ static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		atomic_sub (ret, &pp->irqc);
 		return 0;
 
-	case PPSETTIME:
-		if (copy_from_user (&par_timeout, argp, sizeof(struct timeval))) {
+	case PPSETTIME32:
+		if (copy_from_user(time32, argp, sizeof(time32)))
 			return -EFAULT;
-		}
-		/* Convert to jiffies, place in pp->pdev->timeout */
-		if ((par_timeout.tv_sec < 0) || (par_timeout.tv_usec < 0)) {
-			return -EINVAL;
-		}
-		to_jiffies = ROUND_UP(par_timeout.tv_usec, 1000000/HZ);
-		to_jiffies += par_timeout.tv_sec * (long)HZ;
-		if (to_jiffies <= 0) {
+
+		return pp_set_timeout(pp->pdev, time32[0], time32[1]);
+
+	case PPSETTIME64:
+		if (copy_from_user(time64, argp, sizeof(time64)))
+			return -EFAULT;
+
+		return pp_set_timeout(pp->pdev, time64[0], time64[1]);
+
+	case PPGETTIME32:
+		jiffies_to_timespec64(pp->pdev->timeout, &ts);
+		time32[0] = ts.tv_sec;
+		time32[1] = ts.tv_nsec / NSEC_PER_USEC;
+		if ((time32[0] < 0) || (time32[1] < 0))
 			return -EINVAL;
-		}
-		pp->pdev->timeout = to_jiffies;
+
+		if (copy_to_user(argp, time32, sizeof(time32)))
+			return -EFAULT;
+
 		return 0;
 
-	case PPGETTIME:
-		to_jiffies = pp->pdev->timeout;
-		memset(&par_timeout, 0, sizeof(par_timeout));
-		par_timeout.tv_sec = to_jiffies / HZ;
-		par_timeout.tv_usec = (to_jiffies % (long)HZ) * (1000000/HZ);
-		if (copy_to_user (argp, &par_timeout, sizeof(struct timeval)))
+	case PPGETTIME64:
+		jiffies_to_timespec64(pp->pdev->timeout, &ts);
+		time64[0] = ts.tv_sec;
+		time64[1] = ts.tv_nsec / NSEC_PER_USEC;
+		if ((time64[0] < 0) || (time64[1] < 0))
+			return -EINVAL;
+
+		if (copy_to_user(argp, time64, sizeof(time64)))
 			return -EFAULT;
+
 		return 0;
 
 	default:
-- 
2.1.4

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