libelf/elf32_getphdr.c

/* Get ELF program header table.
   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2005 Red Hat, Inc.
   Written by Ulrich Drepper <drepper@redhat.com>, 1998.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, version 2.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdlib.h>
#include <unistd.h>

#include "libelfP.h"
#include "common.h"

#ifndef LIBELFBITS
# define LIBELFBITS 32
#endif


ElfW2(LIBELFBITS,Phdr) *
elfw2(LIBELFBITS,getphdr) (elf)
     Elf *elf;
{
  ElfW2(LIBELFBITS,Phdr) *result;

  if (elf == NULL)
    return NULL;

  if (unlikely (elf->kind != ELF_K_ELF))
    {
      __libelf_seterrno (ELF_E_INVALID_HANDLE);
      return NULL;
    }

  /* If the program header entry has already been filled in the code
     below must already have been run.  So the class is set, too.  No
     need to waste any more time here.  */
  result = elf->state.ELFW(elf,LIBELFBITS).phdr;
  if (likely (result != NULL))
    return result;

  rwlock_wrlock (elf->lock);

  if (elf->class == 0)
    elf->class = ELFW(ELFCLASS,LIBELFBITS);
  else if (elf->class != ELFW(ELFCLASS,LIBELFBITS))
    {
      __libelf_seterrno (ELF_E_INVALID_CLASS);
      result = NULL;
      goto out;
    }

  if (likely (result == NULL))
    {
      /* Read the section header table.  */
      ElfW2(LIBELFBITS,Ehdr) *ehdr = elf->state.ELFW(elf,LIBELFBITS).ehdr;

      /* If no program header exists return NULL.  */
      size_t phnum = ehdr->e_phnum;
      if (phnum == 0)
	{
	  __libelf_seterrno (ELF_E_NO_PHDR);
	  goto out;
	}

      size_t size = phnum * sizeof (ElfW2(LIBELFBITS,Phdr));

      if (elf->map_address != NULL)
	{
	  /* All the data is already mapped.  Use it.  */
	  if (ehdr->e_ident[EI_DATA] == MY_ELFDATA
	      && (ALLOW_UNALIGNED
		  || (ehdr->e_phoff
		      & (__alignof__ (ElfW2(LIBELFBITS,Phdr)) - 1)) == 0))
	    /* Simply use the mapped data.  */
	    elf->state.ELFW(elf,LIBELFBITS).phdr = (ElfW2(LIBELFBITS,Phdr) *)
	      ((char *) elf->map_address + elf->start_offset + ehdr->e_phoff);
	  else
	    {
	      ElfW2(LIBELFBITS,Phdr) *notcvt;
	      ElfW2(LIBELFBITS,Phdr) *phdr;

	      /* Allocate memory for the program headers.  We know the number
		 of entries from the ELF header.  */
	      phdr = elf->state.ELFW(elf,LIBELFBITS).phdr =
		(ElfW2(LIBELFBITS,Phdr) *) malloc (size);
	      if (elf->state.ELFW(elf,LIBELFBITS).phdr == NULL)
		{
		  __libelf_seterrno (ELF_E_NOMEM);
		  goto out;
		}
	      elf->state.ELFW(elf,LIBELFBITS).phdr_flags |=
		ELF_F_MALLOCED | ELF_F_DIRTY;

	      /* Now copy the data and at the same time convert the
		 byte order.  */
	      if (ALLOW_UNALIGNED
		  || (ehdr->e_phoff
		      & (__alignof__ (ElfW2(LIBELFBITS,Phdr)) - 1)) == 0)
		notcvt = (ElfW2(LIBELFBITS,Phdr) *)
		  ((char *) elf->map_address
		   + elf->start_offset + ehdr->e_phoff);
	      else
		{
		  notcvt = (ElfW2(LIBELFBITS,Phdr) *) alloca (size);
		  memcpy (notcvt, ((char *) elf->map_address +
				   elf->start_offset + ehdr->e_phoff),
			  size);
		}

	      for (size_t cnt = 0; cnt < phnum; ++cnt)
		{
		  CONVERT_TO (phdr[cnt].p_type, notcvt[cnt].p_type);
		  CONVERT_TO (phdr[cnt].p_offset, notcvt[cnt].p_offset);
		  CONVERT_TO (phdr[cnt].p_vaddr, notcvt[cnt].p_vaddr);
		  CONVERT_TO (phdr[cnt].p_paddr, notcvt[cnt].p_paddr);
		  CONVERT_TO (phdr[cnt].p_filesz, notcvt[cnt].p_filesz);
		  CONVERT_TO (phdr[cnt].p_memsz, notcvt[cnt].p_memsz);
		  CONVERT_TO (phdr[cnt].p_flags, notcvt[cnt].p_flags);
		  CONVERT_TO (phdr[cnt].p_align, notcvt[cnt].p_align);
		}
	    }
	}
      else if (likely (elf->fildes != -1))
	{
	  /* Allocate memory for the program headers.  We know the number
	     of entries from the ELF header.  */
	  elf->state.ELFW(elf,LIBELFBITS).phdr =
	    (ElfW2(LIBELFBITS,Phdr) *) malloc (size);
	  if (elf->state.ELFW(elf,LIBELFBITS).phdr == NULL)
	    {
	      __libelf_seterrno (ELF_E_NOMEM);
	      goto out;
	    }
	  elf->state.ELFW(elf,LIBELFBITS).phdr_flags |= ELF_F_MALLOCED;

	  /* Read the header.  */
	  if ((size_t) pread (elf->fildes,
			      elf->state.ELFW(elf,LIBELFBITS).phdr, size,
			      (elf->start_offset + ehdr->e_phoff)) != size)
	    {
	      /* Severe problems.  We cannot read the data.  */
	      __libelf_seterrno (ELF_E_READ_ERROR);
	      free (elf->state.ELFW(elf,LIBELFBITS).phdr);
	      elf->state.ELFW(elf,LIBELFBITS).phdr = NULL;
	      goto out;
	    }

	  /* If the byte order of the file is not the same as the one
	     of the host convert the data now.  */
	  if (ehdr->e_ident[EI_DATA] != MY_ELFDATA)
	    {
	      ElfW2(LIBELFBITS,Phdr) *phdr
		= elf->state.ELFW(elf,LIBELFBITS).phdr;

	      for (size_t cnt = 0; cnt < phnum; ++cnt)
		{
		  CONVERT (phdr[cnt].p_type);
		  CONVERT (phdr[cnt].p_offset);
		  CONVERT (phdr[cnt].p_vaddr);
		  CONVERT (phdr[cnt].p_paddr);
		  CONVERT (phdr[cnt].p_filesz);
		  CONVERT (phdr[cnt].p_memsz);
		  CONVERT (phdr[cnt].p_flags);
		  CONVERT (phdr[cnt].p_align);
		}
	    }
	}
      else
	{
	  /* The file descriptor was already enabled and not all data was
	     read.  */
	  __libelf_seterrno (ELF_E_FD_DISABLED);
	  goto out;
	}

      result = elf->state.ELFW(elf,LIBELFBITS).phdr;
    }

 out:
  rwlock_unlock (elf->lock);

  return result;
}
INTDEF(elfw2(LIBELFBITS,getphdr))