Re: [PATCH] bootup: Add built-in kernel command line for x86

[H. Peter Anvin]

Ingo Molnar wrote:
> * Tim Bird <tim.bird@xxxxxxxxxxx> wrote:
>
> > Add support for a built-in command line for x86 architectures. The 
> > Kconfig help gives the major rationale for this addition.
>
> i have actually used a local hack quite similar to this to inject boot 
> options into bzImages via randconfig - so i would find this feature 
> rather useful.
>
> a small observation:
>
> > +	/* append boot loader cmdline to builtin, unless builtin overrides it */
> > +	if (builtin_cmdline[0] != '!') {
> > +		strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
> > +		strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
> > +		strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
> > +	} else {
> > +		strlcpy(boot_command_line, &builtin_cmdline[1],
> > +			COMMAND_LINE_SIZE);
> > +	}
>
> the default branch changes existing command lines slightly: it appends a 
> space to them. This could break scripts that rely on the precise 
> contents of /proc/cmdline output. (i have some - they are arguably 
> dodgy)
>
> Best would be to make it really apparent in the code that nothing 
> changes if this config option is not set. Preferably there should be no 
> extra code at all in that case.

I would like to see this:

#ifdef CONFIG_BUILTIN_CMDLINE
# ifdef CONFIG_BUILTIN_CMDLINE_OVERRIDE
	strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
# else
	if (boot_command_line) {
		strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
		strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
	}
# endif
#endif

	-hpa

		
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