Re: [PATCH RFC bootconfig] 1/2] fs/proc: Add /proc/cmdline_load for boot loader arguments

[Paul E. McKenney]

On Mon, Aug 07, 2023 at 11:44:55AM +0900, Masami Hiramatsu wrote:
> On Fri, 4 Aug 2023 10:36:17 -0700
> "Paul E. McKenney" <paulmck@xxxxxxxxxx> wrote:
> 
> > On Fri, Aug 04, 2023 at 08:23:20PM +0300, Alexey Dobriyan wrote:
> > > On Thu, Jul 27, 2023 at 08:37:00PM -0700, Paul E. McKenney wrote:
> > > > In kernels built with CONFIG_BOOT_CONFIG_FORCE=y, /proc/cmdline will
> > > > show all kernel boot parameters, both those supplied by the boot loader
> > > > and those embedded in the kernel image.  This works well for those who
> > > > just want to see all of the kernel boot parameters, but is not helpful to
> > > > those who need to see only those parameters supplied by the boot loader.
> > > > This is especially important when these parameters are presented to the
> > > > boot loader by automation that might gather them from diverse sources.
> > > > 
> > > > Therefore, provide a /proc/cmdline_load file that shows only those kernel
> > > > boot parameters supplied by the boot loader.
> > > 
> > > > +static int cmdline_load_proc_show(struct seq_file *m, void *v)
> > > > +{
> > > > +	seq_puts(m, boot_command_line);
> > > > +	seq_putc(m, '\n');
> > > > +	return 0;
> > > > +}
> > > > +
> > > >  static int __init proc_cmdline_init(void)
> > > >  {
> > > >  	struct proc_dir_entry *pde;
> > > > @@ -19,6 +27,11 @@ static int __init proc_cmdline_init(void)
> > > >  	pde = proc_create_single("cmdline", 0, NULL, cmdline_proc_show);
> > > >  	pde_make_permanent(pde);
> > > >  	pde->size = saved_command_line_len + 1;
> > > > +	if (IS_ENABLED(CONFIG_BOOT_CONFIG_FORCE)) {
> > > > +		pde = proc_create_single("cmdline_load", 0, NULL, cmdline_load_proc_show);
> > > > +		pde_make_permanent(pde);
> > > > +		pde->size = strnlen(boot_command_line, COMMAND_LINE_SIZE) + 1;
> > > > +	}
> > > 
> > > Please add it as separate fs/proc/cmdline_load.c file so that name of
> > > the file matches name of the /proc file.
> > 
> > Thank you, will do!
> > 
> > > The name "cmdline_load" is kind of non-descriptive. Mentioning "bootloader"
> > > somewhere should improve things.
> > 
> > If we can all quickly come to agreement on a name, I can of course easily
> > change it.
> > 
> > /proc/cmdline_bootloader?  Better than /proc/cmdline_from_bootloader,
> > I suppose.  /proc/cmdline_bootldr?  /proc/bootloader by analogy with
> > /proc/bootconfig?  Something else?
> 
> What about "/proc/raw_cmdline" ?

That would work of me!

Any objections to /proc/raw_cmdline?

Going once...

							Thanx, Paul