On Sun, 2013-12-29 at 09:32 +0900, Tetsuo Handa wrote:
> Joe Perches wrote:
> > On Sat, 2013-12-28 at 12:08 -0800, Andrew Morton wrote:
> > > On Sat, 28 Dec 2013 11:53:25 -0800 Joe Perches <j...@perches.com> wrote:
> > >
> > > > > > #define PRINTK_PID "\002"
> > > > > > #define PRINTK_TASK_ID "\003" /* "comm:pid" */
> >
> > > > > >
> > > > > > printk(PRINTK_TASK_ID ": hair on fire\n");
> > > > > >
> > > > > > It's certainly compact. I doubt if there's any existing code which
> > > > > > deliberately prints control chars?
>
> What about using bytes from \x7F to \xFF ?
>
> We are not passing multibyte characters like UTF-8 in the format string (are
> we?) because the non-first byte of multibyte characters by error matching %
> will cause security problem (format string bug) because the format string is
> parsed as char array.
>
> Then, we could do something like below.
>
> pr_info("%s", current->comm); => pr_info("\x7F\x80");
> pr_info("%d", current->pid); => pr_info("\x7F\x81");
> pr_info("%10d", current->pid); => pr_info("\x7F10\x81");
>
> If precision field support is unnecessary, we could use only \x80 to \xFF .
>
> pr_info("%s", current->comm); => pr_info("\x80");
> pr_info("%d", current->pid); => pr_info("\x81");
My preference would be to do something like:
$ cat include/asm-generic/current.h
#ifndef __ASM_GENERIC_CURRENT_H
#define __ASM_GENERIC_CURRENT_H
#include <linux/thread_info.h>
#define get_current() (current_thread_info()->task)
#define current get_current()
#define CURRENT_SUB "\032"
#define CURRENT_SUB_ASCII '\032'
#define CURRENT_ID CURRENT_SUB "1"
#define CURRENT_COMM CURRENT_SUB "2"
#define CURRENT_TASK_STATE CURRENT_SUB "3"
#define CURRENT_TASK_PID CURRENT_SUB "4"
#define CURRENT_TASK_GID CURRENT_SUB "5"
#define CURRENT_TASK_UID CURRENT_SUB "6"
#define CURRENT_TASK_FSUID CURRENT_SUB "7"
#define CURRENT_TASK_FSGID CURRENT_SUB "8"
/* add more as necessary */
#endif /* __ASM_GENERIC_CURRENT_H */
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