* Re: [PATCH] Permit big console scrolls
[not found] <200306210621.h5L6LbUo011422@hera.kernel.org>
@ 2003-06-22 9:04 ` Geert Uytterhoeven
2003-06-22 9:36 ` Andrew Morton
0 siblings, 1 reply; 4+ messages in thread
From: Geert Uytterhoeven @ 2003-06-22 9:04 UTC (permalink / raw)
To: Samuel Thibault, Andrew Morton; +Cc: Linux Kernel Development
On Sat, 21 Jun 2003, Linux Kernel Mailing List wrote:
> ChangeSet 1.1381, 2003/06/20 22:14:31-07:00, akpm@digeo.com
>
> [PATCH] Permit big console scrolls
>
> From: Samuel Thibault <Samuel.Thibault@ens-lyon.fr>
>
> Changes the new console scrolling ioctl to permit distances greater than
> +127/-128.
>
>
> # This patch includes the following deltas:
> # ChangeSet 1.1380 -> 1.1381
> # drivers/char/vt.c 1.52 -> 1.53
> #
>
> vt.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletion(-)
>
>
> diff -Nru a/drivers/char/vt.c b/drivers/char/vt.c
> --- a/drivers/char/vt.c Fri Jun 20 23:21:41 2003
> +++ b/drivers/char/vt.c Fri Jun 20 23:21:41 2003
> @@ -75,6 +75,7 @@
> */
>
> #include <linux/module.h>
> +#include <linux/types.h>
> #include <linux/sched.h>
> #include <linux/tty.h>
> #include <linux/tty_flip.h>
> @@ -2279,7 +2280,7 @@
> ret = fg_console;
> break;
> case TIOCL_SCROLLCONSOLE:
> - if (get_user(lines, (char *)arg+1)) {
^^^^^
> + if (get_user(lines, (s32 *)((char *)arg+4))) {
^^^^^
> ret = -EFAULT;
> } else {
> scrollfront(lines);
Why was the `arg+1' changed to `arg+4'? Do we really want to skip 12 bytes?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Permit big console scrolls
2003-06-22 9:04 ` [PATCH] Permit big console scrolls Geert Uytterhoeven
@ 2003-06-22 9:36 ` Andrew Morton
2003-06-22 9:47 ` Geert Uytterhoeven
0 siblings, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2003-06-22 9:36 UTC (permalink / raw)
To: Geert Uytterhoeven; +Cc: Samuel.Thibault, linux-kernel
Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> > - if (get_user(lines, (char *)arg+1)) {
> ^^^^^
> > + if (get_user(lines, (s32 *)((char *)arg+4))) {
> ^^^^^
> > ret = -EFAULT;
> > } else {
> > scrollfront(lines);
>
> Why was the `arg+1' changed to `arg+4'? Do we really want to skip 12 bytes?
It skips three bytes?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Permit big console scrolls
2003-06-22 9:36 ` Andrew Morton
@ 2003-06-22 9:47 ` Geert Uytterhoeven
2003-06-22 10:04 ` Andrew Morton
0 siblings, 1 reply; 4+ messages in thread
From: Geert Uytterhoeven @ 2003-06-22 9:47 UTC (permalink / raw)
To: Andrew Morton; +Cc: Samuel.Thibault, Linux Kernel Development
On Sun, 22 Jun 2003, Andrew Morton wrote:
> Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> >
> > > - if (get_user(lines, (char *)arg+1)) {
> > ^^^^^
> > > + if (get_user(lines, (s32 *)((char *)arg+4))) {
> > ^^^^^
> > > ret = -EFAULT;
> > > } else {
> > > scrollfront(lines);
> >
> > Why was the `arg+1' changed to `arg+4'? Do we really want to skip 12 bytes?
>
> It skips three bytes?
Oops, you're right. But my first question remains: why skip 3 bytes?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Permit big console scrolls
2003-06-22 9:47 ` Geert Uytterhoeven
@ 2003-06-22 10:04 ` Andrew Morton
0 siblings, 0 replies; 4+ messages in thread
From: Andrew Morton @ 2003-06-22 10:04 UTC (permalink / raw)
To: Geert Uytterhoeven; +Cc: Samuel.Thibault, linux-kernel
Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> On Sun, 22 Jun 2003, Andrew Morton wrote:
> > Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > >
> > > > - if (get_user(lines, (char *)arg+1)) {
> > > ^^^^^
> > > > + if (get_user(lines, (s32 *)((char *)arg+4))) {
> > > ^^^^^
> > > > ret = -EFAULT;
> > > > } else {
> > > > scrollfront(lines);
> > >
> > > Why was the `arg+1' changed to `arg+4'? Do we really want to skip 12 bytes?
> >
> > It skips three bytes?
>
> Oops, you're right. But my first question remains: why skip 3 bytes?
Well we want to use a 32-bit quantity, not an 8-bit one. So Samuel aligned
that quantity 32 bits beyond the 8-bit ioctl `type' arg.
So I guess you'd do:
struct foo {
char type;
char pad[3];
s32 distance;
};
^ permalink raw reply [flat|nested] 4+ messages in thread
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[not found] <200306210621.h5L6LbUo011422@hera.kernel.org>
2003-06-22 9:04 ` [PATCH] Permit big console scrolls Geert Uytterhoeven
2003-06-22 9:36 ` Andrew Morton
2003-06-22 9:47 ` Geert Uytterhoeven
2003-06-22 10:04 ` Andrew Morton
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