Sasha Levin <levinsasha928@xxxxxxxxx> writes:
> Provide a callback that will be called when writing to a ctl_table
> entry after the user input has been validated.
>
> This will simplify user input checks since now it will be possible to
> remove them out of the proc_handler.
Ick No.
You are simplifying things by taking updates out of locks, and
introducing races.
Your naming of the callback "callback" is much too generic.
I think the current function call mechanism of sysctl can be improved
but I don't think you have come up with the right combination of things.
Eric
> Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx>
> ---
> fs/proc/proc_sysctl.c | 4 ++++
> include/linux/sysctl.h | 1 +
> 2 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
> index 21d836f..190db28 100644
> --- a/fs/proc/proc_sysctl.c
> +++ b/fs/proc/proc_sysctl.c
> @@ -507,6 +507,10 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
> error = table->proc_handler(table, write, buf, &res, ppos);
> if (!error)
> error = res;
> +
> + if (!error && write && table->callback)
> + error = table->callback();
> +
> out:
> sysctl_head_finish(head);
>
> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
> index c34b4c8..27c14cf 100644
> --- a/include/linux/sysctl.h
> +++ b/include/linux/sysctl.h
> @@ -1022,6 +1022,7 @@ struct ctl_table
> struct ctl_table_poll *poll;
> void *extra1;
> void *extra2;
> + int (*callback)(void); /* Called when entry is written to */
> };
>
> struct ctl_node {
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