Re: [XEN PATCH] xen: address MISRA C:2012 Rule 4.1

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 19 Jul 2023, Nicola Vetrini wrote:
> MISRA C:2012 Rule 4.1 has the following headline:
> "Octal and hexadecimal escape sequences shall be terminated."
> 
> The string literals modified by this patch contain octal or
> hexadecimal escape sequences that are neither terminated by the
> end of the literal, nor by the beginning of another escape sequence.
> 
> Therefore, such unterminated sequences have been split into a
> separate literal as a way to comply with the rule and preserve the
> semantics of the code.
> 
> No functional changes.
> 
> Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> The choice whether to put a blank between the literals is up to
> the maintainers' preference, I chose to do so to improve legibility.
> ---
>  xen/arch/x86/hvm/hvm.c  | 2 +-
>  xen/common/decompress.c | 4 ++--
>  xen/common/xz/stream.h  | 2 +-
>  3 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index 57363c2ae1..24ccf60d77 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -3853,7 +3853,7 @@ void hvm_ud_intercept(struct cpu_user_regs *regs)
>                                          cs, &addr) &&
>               (hvm_copy_from_guest_linear(sig, addr, sizeof(sig),
>                                           walk, NULL) == HVMTRANS_okay) &&
> -             (memcmp(sig, "\xf\xbxen", sizeof(sig)) == 0) )
> +             (memcmp(sig, "\xf\xb" "xen", sizeof(sig)) == 0) )
>          {
>              regs->rip += sizeof(sig);
>              regs->eflags &= ~X86_EFLAGS_RF;
> diff --git a/xen/common/decompress.c b/xen/common/decompress.c
> index 989336983f..2c2c2ad877 100644
> --- a/xen/common/decompress.c
> +++ b/xen/common/decompress.c
> @@ -19,13 +19,13 @@ int __init decompress(void *inbuf, unsigned int len, void 
> *outbuf)
>      if ( len >= 3 && !memcmp(inbuf, "\x42\x5a\x68", 3) )
>          return bunzip2(inbuf, len, NULL, NULL, outbuf, NULL, error);
>  
> -    if ( len >= 6 && !memcmp(inbuf, "\3757zXZ", 6) )
> +    if ( len >= 6 && !memcmp(inbuf, "\375" "7zXZ", 6) )
>          return unxz(inbuf, len, NULL, NULL, outbuf, NULL, error);
>  
>      if ( len >= 2 && !memcmp(inbuf, "\135\000", 2) )
>          return unlzma(inbuf, len, NULL, NULL, outbuf, NULL, error);
>  
> -    if ( len >= 5 && !memcmp(inbuf, "\x89LZO", 5) )
> +    if ( len >= 5 && !memcmp(inbuf, "\x89" "LZO", 5) )
>          return unlzo(inbuf, len, NULL, NULL, outbuf, NULL, error);
>  
>      if ( len >= 2 && !memcmp(inbuf, "\x02\x21", 2) )
> diff --git a/xen/common/xz/stream.h b/xen/common/xz/stream.h
> index d36d0fec64..8d9fbbe1b5 100644
> --- a/xen/common/xz/stream.h
> +++ b/xen/common/xz/stream.h
> @@ -18,7 +18,7 @@
>  
>  #define STREAM_HEADER_SIZE 12
>  
> -#define HEADER_MAGIC "\3757zXZ"
> +#define HEADER_MAGIC "\375" "7zXZ"
>  #define HEADER_MAGIC_SIZE 6
>  
>  #define FOOTER_MAGIC "YZ"
> -- 
> 2.34.1
>