I think it is good for you to read LDD3 or google some corresponding
materials at first.
2014-05-27 20:48 GMT+08:00 Lucas Tanure :
> Hi!
>
> Goal, when the user do :
> # head -1 /dev/miscdrv
>
> The driver prints: Hello World!
>
> Steps:
> # Make
> # insmod misc.ko
> # head -1 /dev/miscdrv
>
> Wh
Hi!
On Die, 2014-05-27 at 10:09 -0300, Lucas Tanure wrote:
> Wow, many thanks.
> So the read operation should return the total number of bytes, not a
> true/false int.
The syscall here (done by `head`) is read() ...
> I need to read more about this operations.
.. and the drivers .read function
Wow, many thanks.
So the read operation should return the total number of bytes, not a
true/false int.
I need to read more about this operations.
Thanks
--
Lucas Tanure
+55 (19) 988176559
On Tue, May 27, 2014 at 10:05 AM, Bjørn Mork wrote:
> Lucas Tanure writes:
>
> > So, My misc_drv_read r
Lucas Tanure writes:
> So, My misc_drv_read returns 0, and it's ok. So why the command head didn't
> get the string ?
You told it that it got a string with length 0. And that's what it printed.
Bjørn
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So, My misc_drv_read returns 0, and it's ok. So why the command head didn't
get the string ?
--
Lucas Tanure
+55 (19) 988176559
On Tue, May 27, 2014 at 9:59 AM, Bjørn Mork wrote:
> Lucas Tanure writes:
>
> >> What is worg with my read operation?
> >
> > static ssize_t
> > misc_drv_read(struct
Lucas Tanure writes:
>> What is worg with my read operation?
>
> static ssize_t
> misc_drv_read(struct file *filp, char __user * buf, size_t count, loff_t *
> offp){
> int nbytes;
> char * string = "hello World";
> nbytes = copy_to_user(buf, string, 12);
> return nbytes;
> }
copy_to_user re
Hi!
Goal, when the user do :
# head -1 /dev/miscdrv
The driver prints: Hello World!
Steps:
# Make
# insmod misc.ko
# head -1 /dev/miscdrv
Why my driver doesn't work ?
What is worg with my read operation?
static ssize_t
misc_drv_read(struct file *filp, char __user * buf, size_t count, loff_t
