Re: [Xen-devel] ELF header data types / elfstructs.h, Elf64_Half, Elf64_Quarter

[Keir Fraser <keir@xxxxxxx>]

On 16/11/2011 17:20, "Volker Eckert" <volker.eckert@xxxxxxxxxx> wrote:

> hi,
> 
> according to two ELF standard documents, namely
> http://downloads.openwatcom.org/ftp/devel/docs/elf-64-gen.pdf
> and
> http://ftp.parisc-linux.org/docs/arch/elf-64-hp.pdf
> 
> Elf64_Half should be uint16_t and not uint32_t as it is currently
> defined in elfstructs.h
> 
> i guess this is, because Elf.._Half is supposed to mean 'half a word'
> (whatever that was at that time) and not 'half of 64 bits' like the name
> could suggest.
> 
> in that context i'd suggest replacing occurences of Elf64_Quarter with
> Elf64_Half and removing its definition - but as it is not defined in the
> standard it is more of a cosmetic issue.
> 
> please find a patch against xen-unstable below - i hope this is
> acceptable(?). as i'm not subscribed to the list please CC me in
> replies, thanks!

Yes, but in fact it could go further because Elf64_Quarter is not needed,
nor defined in the spec.

I have gone through the spec and done the further fixups.

The complete patch is now in xen-unstable as c/s 24154.

 Thanks!
 Keir

> volker
> 
> 
> p. s.: i think there is a check for Python.h missing in some configure.in
> 
> 
> 
> 
> 
> 
> diff --git a/tools/libxc/xc_dom_elfloader.c b/tools/libxc/xc_dom_elfloader.c
> index 906e3a2..4d7b8e0 100644
> --- a/tools/libxc/xc_dom_elfloader.c
> +++ b/tools/libxc/xc_dom_elfloader.c
> @@ -237,7 +237,7 @@ static int xc_dom_load_elf_symtab(struct
> xc_dom_image *dom,
> 
>           /* Name is NULL. */
>           if ( elf_64bit(&syms) )
> -            *(Elf64_Half*)(&shdr->e64.sh_name) = 0;
> +            *(Elf64_Word*)(&shdr->e64.sh_name) = 0;
>           else
>               *(Elf32_Word*)(&shdr->e32.sh_name) = 0;
>       }
> diff --git a/xen/include/xen/elfstructs.h b/xen/include/xen/elfstructs.h
> index 62f9399..1c46cd4 100644
> --- a/xen/include/xen/elfstructs.h
> +++ b/xen/include/xen/elfstructs.h
> @@ -44,7 +44,7 @@ typedef uint32_t      Elf64_Word;
>   typedef int64_t                Elf64_Sxword;
>   typedef uint64_t       Elf64_Xword;
> 
> -typedef uint32_t       Elf64_Half;
> +typedef uint16_t       Elf64_Half;
>   typedef uint16_t       Elf64_Quarter;
> 
>   /*
> @@ -129,11 +129,11 @@ typedef struct {
>          unsigned char   e_ident[EI_NIDENT];     /* Id bytes */
>          Elf64_Quarter   e_type;                 /* file type */
>          Elf64_Quarter   e_machine;              /* machine type */
> -       Elf64_Half      e_version;              /* version number */
> +       Elf64_Word      e_version;              /* version number */
>          Elf64_Addr      e_entry;                /* entry point */
>          Elf64_Off       e_phoff;                /* Program hdr offset */
>          Elf64_Off       e_shoff;                /* Section hdr offset */
> -       Elf64_Half      e_flags;                /* Processor flags */
> +       Elf64_Word      e_flags;                /* Processor flags */
>          Elf64_Quarter   e_ehsize;               /* sizeof ehdr */
>          Elf64_Quarter   e_phentsize;            /* Program header entry
> size */
>          Elf64_Quarter   e_phnum;                /* Number of program
> headers */
> @@ -202,14 +202,14 @@ typedef struct {
>   } Elf32_Shdr;
> 
>   typedef struct {
> -       Elf64_Half      sh_name;        /* section name */
> -       Elf64_Half      sh_type;        /* section type */
> +       Elf64_Word      sh_name;        /* section name */
> +       Elf64_Word      sh_type;        /* section type */
>          Elf64_Xword     sh_flags;       /* section flags */
>          Elf64_Addr      sh_addr;        /* virtual address */
>          Elf64_Off       sh_offset;      /* file offset */
>          Elf64_Xword     sh_size;        /* section size */
> -       Elf64_Half      sh_link;        /* link to another */
> -       Elf64_Half      sh_info;        /* misc info */
> +       Elf64_Word      sh_link;        /* link to another */
> +       Elf64_Word      sh_info;        /* misc info */
>          Elf64_Xword     sh_addralign;   /* memory alignment */
>          Elf64_Xword     sh_entsize;     /* table entry size */
>   } Elf64_Shdr;
> @@ -284,7 +284,7 @@ typedef struct elf32_sym {
>   } Elf32_Sym;
> 
>   typedef struct {
> -       Elf64_Half      st_name;        /* Symbol name index in str table */
> +       Elf64_Word      st_name;        /* Symbol name index in str table */
>          Elf_Byte        st_info;        /* type / binding attrs */
>          Elf_Byte        st_other;       /* unused */
>          Elf64_Quarter   st_shndx;       /* section index of symbol */
> @@ -368,8 +368,8 @@ typedef struct {
>   } Elf32_Phdr;
> 
>   typedef struct {
> -       Elf64_Half      p_type;         /* entry type */
> -       Elf64_Half      p_flags;        /* flags */
> +       Elf64_Word      p_type;         /* entry type */
> +       Elf64_Word      p_flags;        /* flags */
>          Elf64_Off       p_offset;       /* offset */
>          Elf64_Addr      p_vaddr;        /* virtual address */
>          Elf64_Addr      p_paddr;        /* physical address */
> @@ -458,9 +458,9 @@ typedef struct {
>   } Elf32_Note;
> 
>   typedef struct {
> -       Elf64_Half namesz;
> -       Elf64_Half descsz;
> -       Elf64_Half type;
> +       Elf64_Word namesz;
> +       Elf64_Word descsz;
> +       Elf64_Word type;
>   } Elf64_Note;
> 
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