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

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Fri, 26 Apr 2024, Jan Beulich wrote:
> 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?

I can look into it


> > +   * - `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.

Good point