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SubjectRe: [PATCH] drivers/char/ppdev.c: returning copy_to_user result
Em Fri, Aug 25, 2000 at 09:41:37AM -0500, Michael Elizabeth Chastain escreveu:
> > Please take a look and consider applying. Feedback about why it would
> > be wrong would be greatly appreciated.
>
> I eyeballed this and it looks correct to me, except that the comment
> at the top is slightly wrong.
>
> On error, copy_from_user and copy_to_user do not return -EFAULT,
> They return the positive number of bytes *not* copied due to address
> space errors.

Ok, fixed. 8)

- Arnaldo

--- linux-2.4.0-test7/drivers/char/ppdev.c Thu Jul 13 01:58:42 2000
+++ linux-2.4.0-test7.acme/drivers/char/ppdev.c Fri Aug 25 09:00:36 2000
@@ -39,7 +39,13 @@
* read/write read or write in current IEEE 1284 protocol
* select wait for interrupt (in readfds)
*
+ * Changes:
* Added SETTIME/GETTIME ioctl, Fred Barnes 1999.
+ *
+ * Arnaldo Carvalho de Melo <acme@conectiva.com.br> 2000/08/25
+ * - On error, copy_from_user and copy_to_user do not return -EFAULT,
+ * They return the positive number of bytes *not* copied due to address
+ * space errors.
*/

#include <linux/module.h>
@@ -369,19 +375,19 @@

case PPRSTATUS:
reg = parport_read_status (port);
- return copy_to_user ((unsigned char *) arg, &reg,
- sizeof (reg));
-
+ if (copy_to_user ((unsigned char *) arg, &reg, sizeof (reg)))
+ return -EFAULT;
+ return 0;
case PPRDATA:
reg = parport_read_data (port);
- return copy_to_user ((unsigned char *) arg, &reg,
- sizeof (reg));
-
+ if (copy_to_user ((unsigned char *) arg, &reg, sizeof (reg)))
+ return -EFAULT;
+ return 0;
case PPRCONTROL:
reg = parport_read_control (port);
- return copy_to_user ((unsigned char *) arg, &reg,
- sizeof (reg));
-
+ if (copy_to_user ((unsigned char *) arg, &reg, sizeof (reg)))
+ return -EFAULT;
+ return 0;
case PPYIELD:
parport_yield_blocking (pp->pdev);
return 0;
-
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