Re: [PATCH] x86/setup: replace strlcat() with snprintf() in setup_arch()

[Andy Shevchenko]

On Thu, Jun 04, 2026 at 03:17:53PM +0200, Thorsten Blum wrote:
> In preparation to remove strlcat() from the kernel [1], replace two
> strlcat() calls with one snprintf() call in setup_arch().
> 
> Also drop the explicit size argument of strscpy() to further simplify
> the code since strscpy() can determine the size automatically when the
> destination buffer has a fixed length.

> [1] https://github.com/KSPP/linux/issues/370

Make it Link tag?

...

>  	strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);

This also has third argument fixed. Don't you want to change that?

>  #else
>  	if (builtin_cmdline[0]) {
> +		size_t len = strnlen(builtin_cmdline, COMMAND_LINE_SIZE);
> +
>  		/* append boot loader cmdline to builtin */
> -		strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
> -		strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
> +		snprintf(builtin_cmdline + len, COMMAND_LINE_SIZE - len, " %s",
> +			 boot_command_line);

Hmm... Wouldn't GCC complain on this? (Build with `make W=1`.)

>  		strscpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);

And this has also third argument.

>  	}
>  #endif
>  	builtin_cmdline_added = true;
>  #endif
>  
> -	strscpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
> +	strscpy(command_line, boot_command_line);

-- 
With Best Regards,
Andy Shevchenko