Re: ELF header data types / elfstructs.h, Elf64_Half, Elf64_Quarter

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 16/11/11 17:42, Andrew Cooper wrote:
> On 16/11/11 17:20, Volker Eckert 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
> This agrees with /usr/include/linux/elf.h so it is probably a good idea
> to fix.
>
>> 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!
> Please read http://wiki.xen.org/wiki/SubmittingXenPatches
>
> Specifically, you need to make a declaration of origin.
>
> It is a good idea to attach your patch as a file as quite a few mail
> clients mangle whitespace of the email text.  Also, being on the
> xen-devel mailing list is a Very Good Idea.

P.S. Please match the whitespace conventions of the file you are working
in, which you have not done in your submitted patch.

~Andrew

>> 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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>> Xen-devel@lists.xensource.com
>> http://lists.xensource.com/xen-devel

-- 
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com