Re: [PATCH v2] docs/misra: add R21.6 R21.9 R21.10 R21.14 R21.15 R21.16

[Jan Beulich <jbeulich@xxxxxxxx>]

On 26.04.2024 01:31, Stefano Stabellini wrote:
> --- a/docs/misra/rules.rst
> +++ b/docs/misra/rules.rst
> @@ -652,12 +652,72 @@ maintainers if you want to suggest a change.
>         declared
>       - See comment for Rule 21.1
>  
> +   * - `Rule 21.6 
> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_06.c>`_
> +     - Required
> +     - The Standard Library input/output routines shall not be used
> +     - Xen doesn't provide, use, or link against any Standard Library.
> +       Xen implements itself a few functions with names that match the
> +       corresponding function names of the Standard Library for
> +       developers' convenience. These functions are part of the Xen code
> +       and subject to analysis.
> +
> +   * - `Rule 21.9 
> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_09.c>`_
> +     - Required
> +     - The library functions bsearch and qsort of <stdlib.h> shall not be 
> used
> +     - Xen doesn't provide, use, or link against any Standard Library.
> +       Xen implements itself a few functions with names that match the
> +       corresponding function names of the Standard Library for
> +       developers' convenience. These functions are part of the Xen code
> +       and subject to analysis.
> +
> +   * - `Rule 21.10 
> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_10.c>`_
> +     - Required
> +     - The Standard Library time and date routines shall not be used
> +     - Xen doesn't provide, use, or link against any Standard Library.
> +       Xen implements itself a few functions with names that match the
> +       corresponding function names of the Standard Library for
> +       developers' convenience. These functions are part of the Xen code
> +       and subject to analysis.
> +
>     * - `Rule 21.13 
> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_13.c>`_
>       - Mandatory
>       - Any value passed to a function in <ctype.h> shall be representable as 
> an
>         unsigned char or be the value EOF
>       -

Up to here, did you consider adding a short reference to some common blob
(footnote or alike), rather than repeating the same text verbatim several
times?

> +   * - `Rule 21.14 
> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_14.c>`_
> +     - Required
> +     - The Standard Library function memcmp shall not be used to compare
> +       null terminated strings
> +     - Xen doesn't provide, use, or link against any Standard Library.
> +       Xen implements itself a few functions with names that match the
> +       corresponding function names of the Standard Library for
> +       developers' convenience. These functions are part of the Xen code
> +       and subject to analysis.
> +
> +   * - `Rule 21.15 
> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_15.c>`_
> +     - Required
> +     - The pointer arguments to the Standard Library functions memcpy,
> +       memmove and memcmp shall be pointers to qualified or unqualified
> +       versions of compatible types
> +     - Xen doesn't provide, use, or link against any Standard Library.
> +       Xen implements itself a few functions with names that match the
> +       corresponding function names of the Standard Library for
> +       developers' convenience. These functions are part of the Xen code
> +       and subject to analysis.
> +
> +   * - `Rule 21.16 
> <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_21_16.c>`_
> +     - Required
> +     - The pointer arguments to the Standard Library function memcmp
> +       shall point to either a pointer type, an essentially signed type,
> +       an essentially unsigned type, an essentially Boolean type or an
> +       essentially enum type
> +     - void* arguments are allowed. Xen doesn't provide, use, or link
> +       against any Standard Library.  Xen implements itself a few
> +       functions with names that match the corresponding function names
> +       of the Standard Library for developers' convenience. These
> +       functions are part of the Xen code and subject to analysis.

For all three of these I'm not convinced the remark is appropriate. These
talk about specific properties of the functions, which aren't related to
risks associated with particular (and hence potentially varying) library
implementations.

Jan