Re: [PATCH v2] Suport for bi-endianess in elf file

[Andrei Borzenkov <arvidjaar@gmail.com>]

В Thu, 23 Jul 2015 11:10:36 -0300
Paulo Flabiano Smorigo <pfsmorigo@linux.vnet.ibm.com> пишет:

> Updated version with the suggestions from Andrei Borzenkov.
> 
> * grub-core/kern/elf.c: check and switch endianess with grub_{be,le}_to
> cpu functions.
> * grub-core/kern/elfXX.c: Likewise.
> 

Could you add a bit more verbose description that it currently applies
to ppc only when committing.

> Also-by: Tomohiro B Berry <tbberry@us.ibm.com>
> ---
>  grub-core/kern/elf.c   | 51 ++++++++++++++++++++++++++++++---
>  grub-core/kern/elfXX.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 123 insertions(+), 4 deletions(-)
> 
> diff --git a/grub-core/kern/elf.c b/grub-core/kern/elf.c
> index 5f99c43..1be9c1c 100644
> --- a/grub-core/kern/elf.c
> +++ b/grub-core/kern/elf.c
> @@ -28,6 +28,11 @@
>  
>  GRUB_MOD_LICENSE ("GPLv3+");
>  
> +#if defined(__powerpc__) && defined(GRUB_MACHINE_IEEE1275)
> +void grub_elf32_check_endianess (grub_elf_t elf);
> +void grub_elf64_check_endianess (grub_elf_t elf);
> +#endif /* defined(__powerpc__) && defined(GRUB_MACHINE_IEEE1275) */
> +
>  /* Check if EHDR is a valid ELF header.  */
>  static grub_err_t
>  grub_elf_check_header (grub_elf_t elf)
> @@ -38,8 +43,19 @@ grub_elf_check_header (grub_elf_t elf)
>        || e->e_ident[EI_MAG1] != ELFMAG1
>        || e->e_ident[EI_MAG2] != ELFMAG2
>        || e->e_ident[EI_MAG3] != ELFMAG3
> -      || e->e_ident[EI_VERSION] != EV_CURRENT
> -      || e->e_version != EV_CURRENT)
> +      || e->e_ident[EI_VERSION] != EV_CURRENT)
> +    return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-independent ELF magic"));
> +
> +#if defined(__powerpc__) && defined(GRUB_MACHINE_IEEE1275)
> +  if (grub_elf_is_elf32 (elf))
> +      grub_elf32_check_endianess (elf);
> +  else if (grub_elf_is_elf64 (elf))
> +      grub_elf64_check_endianess (elf);
> +  else
> +    return grub_error (GRUB_ERR_BAD_OS, N_("Uknown ELF class"));

Other places are using "invalid arch-dependent ELF magic" in this case,
it is better to reuse translation string. Otherwise fine for me. 

> +#endif /* defined(__powerpc__) && defined(GRUB_MACHINE_IEEE1275) */
> +
> +  if (e->e_version != EV_CURRENT)
>      return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-independent ELF magic"));
>  
>    return GRUB_ERR_NONE;
> @@ -116,7 +132,11 @@ grub_elf_open (const char *name)
>    return elf;
>  }
>  
> -\f
> +#define grub_be_to_halfXX grub_be_to_cpu16
> +#define grub_le_to_halfXX grub_le_to_cpu16
> +#define grub_be_to_wordXX grub_be_to_cpu32
> +#define grub_le_to_wordXX grub_le_to_cpu32
> +
>  /* 32-bit */
>  #define ehdrXX ehdr32
>  #define ELFCLASSXX ELFCLASS32
> @@ -127,7 +147,15 @@ grub_elf_open (const char *name)
>  #define grub_elf_is_elfXX grub_elf_is_elf32
>  #define grub_elfXX_load_phdrs grub_elf32_load_phdrs
>  #define ElfXX_Phdr Elf32_Phdr
> +#define ElfXX_Ehdr Elf32_Ehdr
>  #define grub_uintXX_t grub_uint32_t
> +#define grub_be_to_addrXX grub_be_to_cpu32
> +#define grub_le_to_addrXX grub_le_to_cpu32
> +#define grub_be_to_offXX grub_be_to_cpu32
> +#define grub_le_to_offXX grub_le_to_cpu32
> +#define grub_be_to_XwordXX grub_be_to_cpu32
> +#define grub_le_to_XwordXX grub_le_to_cpu32
> +#define grub_elfXX_check_endianess grub_elf32_check_endianess
>  
>  #include "elfXX.c"
>  
> @@ -140,9 +168,16 @@ grub_elf_open (const char *name)
>  #undef grub_elf_is_elfXX
>  #undef grub_elfXX_load_phdrs
>  #undef ElfXX_Phdr
> +#undef ElfXX_Ehdr
>  #undef grub_uintXX_t
> +#undef grub_be_to_addrXX
> +#undef grub_le_to_addrXX
> +#undef grub_be_to_offXX
> +#undef grub_le_to_offXX
> +#undef grub_be_to_XwordXX
> +#undef grub_le_to_XwordXX
> +#undef grub_elfXX_check_endianess
>  
> -\f
>  /* 64-bit */
>  #define ehdrXX ehdr64
>  #define ELFCLASSXX ELFCLASS64
> @@ -153,6 +188,14 @@ grub_elf_open (const char *name)
>  #define grub_elf_is_elfXX grub_elf_is_elf64
>  #define grub_elfXX_load_phdrs grub_elf64_load_phdrs
>  #define ElfXX_Phdr Elf64_Phdr
> +#define ElfXX_Ehdr Elf64_Ehdr
>  #define grub_uintXX_t grub_uint64_t
> +#define grub_be_to_addrXX grub_be_to_cpu64
> +#define grub_le_to_addrXX grub_le_to_cpu64
> +#define grub_be_to_offXX grub_be_to_cpu64
> +#define grub_le_to_offXX grub_le_to_cpu64
> +#define grub_be_to_XwordXX grub_be_to_cpu64
> +#define grub_le_to_XwordXX grub_le_to_cpu64
> +#define grub_elfXX_check_endianess grub_elf64_check_endianess
>  
>  #include "elfXX.c"
> diff --git a/grub-core/kern/elfXX.c b/grub-core/kern/elfXX.c
> index 1d09971..c14e071 100644
> --- a/grub-core/kern/elfXX.c
> +++ b/grub-core/kern/elfXX.c
> @@ -31,6 +31,39 @@ grub_elfXX_load_phdrs (grub_elf_t elf)
>        return grub_errno;
>      }
>  
> +#if defined(__powerpc__) && defined(GRUB_MACHINE_IEEE1275)
> +  ElfXX_Phdr *phdr;
> +  for (phdr = elf->phdrs;
> +       phdr && phdr < (ElfXX_Phdr *) elf->phdrs + elf->ehdr.ehdrXX.e_phnum;
> +       phdr++)
> +    {
> +      if (elf->ehdr.ehdrXX.e_ident[EI_DATA] == ELFDATA2LSB)
> +        {
> +          phdr->p_type = grub_le_to_wordXX (phdr->p_type);
> +          phdr->p_flags = grub_le_to_wordXX (phdr->p_flags);
> +          phdr->p_offset = grub_le_to_offXX (phdr->p_offset);
> +          phdr->p_vaddr = grub_le_to_addrXX (phdr->p_vaddr);
> +          phdr->p_paddr = grub_le_to_addrXX (phdr->p_paddr);
> +          phdr->p_filesz = grub_le_to_XwordXX (phdr->p_filesz);
> +          phdr->p_memsz = grub_le_to_XwordXX (phdr->p_memsz);
> +          phdr->p_align = grub_le_to_XwordXX (phdr->p_align);
> +        }
> +#if !defined(GRUB_CPU_WORDS_BIGENDIAN) && 0
> +      else if (elf->ehdr.ehdrXX.e_ident[EI_DATA] == ELFDATA2MSB)
> +        {
> +          phdr->p_type = grub_be_to_wordXX (phdr->p_type);
> +          phdr->p_flags = grub_be_to_wordXX (phdr->p_flags);
> +          phdr->p_offset = grub_be_to_offXX (phdr->p_offset);
> +          phdr->p_vaddr = grub_be_to_addrXX (phdr->p_vaddr);
> +          phdr->p_paddr = grub_be_to_addrXX (phdr->p_paddr);
> +          phdr->p_filesz = grub_be_to_XwordXX (phdr->p_filesz);
> +          phdr->p_memsz = grub_be_to_XwordXX (phdr->p_memsz);
> +          phdr->p_align = grub_be_to_XwordXX (phdr->p_align);
> +        }
> +#endif /* !defined(GRUB_CPU_WORDS_BIGENDIAN) && 0 */
> +    }
> +#endif /* defined(__powerpc__) && defined(GRUB_MACHINE_IEEE1275) */
> +
>    return GRUB_ERR_NONE;
>  }
>  
> @@ -154,3 +187,46 @@ grub_elfXX_load (grub_elf_t elf, const char *filename,
>  
>    return grub_errno;
>  }
> +
> +#if defined(__powerpc__) && defined(GRUB_MACHINE_IEEE1275)
> +void
> +grub_elfXX_check_endianess (grub_elf_t elf)
> +{
> +  ElfXX_Ehdr *e = &(elf->ehdr.ehdrXX);
> +
> +  if (e->e_ident[EI_DATA] == ELFDATA2LSB)
> +    {
> +      e->e_type = grub_le_to_halfXX (e->e_type);
> +      e->e_machine = grub_le_to_halfXX (e->e_machine);
> +      e->e_version = grub_le_to_wordXX (e->e_version);
> +      e->e_entry = grub_le_to_addrXX (e->e_entry);
> +      e->e_phoff = grub_le_to_offXX (e->e_phoff);
> +      e->e_shoff = grub_le_to_offXX (e->e_shoff);
> +      e->e_flags = grub_le_to_wordXX (e->e_flags);
> +      e->e_ehsize = grub_le_to_halfXX (e->e_ehsize);
> +      e->e_phentsize = grub_le_to_halfXX (e->e_phentsize);
> +      e->e_phnum = grub_le_to_halfXX (e->e_phnum);
> +      e->e_shentsize = grub_le_to_halfXX (e->e_shentsize);
> +      e->e_shnum = grub_le_to_halfXX (e->e_shnum);
> +      e->e_shstrndx = grub_le_to_halfXX (e->e_shstrndx);
> +    }
> +#if !defined(GRUB_CPU_WORDS_BIGENDIAN) && 0
> +  else if (e->e_ident[EI_DATA] == ELFDATA2MSB)
> +    {
> +      e->e_type = grub_be_to_halfXX (e->e_type);
> +      e->e_machine = grub_be_to_halfXX (e->e_machine);
> +      e->e_version = grub_be_to_wordXX (e->e_version);
> +      e->e_entry = grub_be_to_addrXX (e->e_entry);
> +      e->e_phoff = grub_be_to_offXX (e->e_phoff);
> +      e->e_shoff = grub_be_to_offXX (e->e_shoff);
> +      e->e_flags = grub_be_to_wordXX (e->e_flags);
> +      e->e_ehsize = grub_be_to_halfXX (e->e_ehsize);
> +      e->e_phentsize = grub_be_to_halfXX (e->e_phentsize);
> +      e->e_phnum = grub_be_to_halfXX (e->e_phnum);
> +      e->e_shentsize = grub_be_to_halfXX (e->e_shentsize);
> +      e->e_shnum = grub_be_to_halfXX (e->e_shnum);
> +      e->e_shstrndx = grub_be_to_halfXX (e->e_shstrndx);
> +    }
> +#endif /* !defined(GRUB_CPU_WORDS_BIGENDIAN) && 0 */
> +}
> +#endif /* defined(__powerpc__) && defined(GRUB_MACHINE_IEEE1275) */