Re: [PATCH v6 08/22] bootconfig: init: Allow admin to use bootconfig for init command line

[Arvind Sankar <nivedita@alum.mit.edu>]

On Fri, Feb 07, 2020 at 02:46:03PM -0500, Steven Rostedt wrote:
> 
> diff --git a/init/main.c b/init/main.c
> index 491f1cdb3105..113c8244e5f0 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -142,6 +142,15 @@ static char *extra_command_line;
>  /* Extra init arguments */
>  static char *extra_init_args;
>  
> +#ifdef CONFIG_BOOT_CONFIG
> +/* Is bootconfig on command line? */
> +static bool bootconfig_found;
> +static bool initargs_found;
> +#else
> +# define bootconfig_found false
> +# define initargs_found false
> +#endif
> +
>  static char *execute_command;
>  static char *ramdisk_execute_command;
>  
> @@ -336,17 +345,32 @@ u32 boot_config_checksum(unsigned char *p, u32 size)
>  	return ret;
>  }
>  
> +static int __init bootconfig_params(char *param, char *val,
> +				    const char *unused, void *arg)
> +{
> +	if (strcmp(param, "bootconfig") == 0) {
> +		bootconfig_found = true;
> +	} else if (strcmp(param, "--") == 0) {
> +		initargs_found = true;
> +	}
> +	return 0;
> +}
> +

I came across this as I was poking around some of the command line
parsing. AFAICT, initargs_found will never be set to true here, because
parse_args handles "--" itself by immediately returning: it doesn't
invoke the callback for it. So you'd instead have to check the return of
parse_args("bootconfig"...) to detect the initargs_found case.

>  static void __init setup_boot_config(const char *cmdline)
>  {
> +	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
>  	u32 size, csum;
>  	char *data, *copy;
>  	const char *p;
>  	u32 *hdr;
>  	int ret;
>  
> -	p = strstr(cmdline, "bootconfig");
> -	if (!p || (p != cmdline && !isspace(*(p-1))) ||
> -	    (p[10] && !isspace(p[10])))
> +	/* All fall through to do_early_param. */
> +	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
> +	parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
> +		   bootconfig_params);
> +
> +	if (!bootconfig_found)
>  		return;