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/* Support for 32-bit i386 NLM (NetWare Loadable Module)

   Copyright (C) 1993 Free Software Foundation, Inc.

This file is part of BFD, the Binary File Descriptor library.

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; either version 2 of the License, or

(at your option) any later version.

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.  */

#include "bfd.h"

#include "sysdep.h"

#include "libbfd.h"

#define ARCH_SIZE 32

#include "nlm/i386-ext.h"

#define Nlm_External_Fixed_Header       Nlm32_i386_External_Fixed_Header

#include "libnlm.h"

static boolean nlm_i386_read_reloc

  PARAMS ((bfd *, nlmNAME(symbol_type) *, asection **, arelent *));

static boolean nlm_i386_write_import

  PARAMS ((bfd *, asection *, arelent *));

static boolean nlm_i386_mangle_relocs

  PARAMS ((bfd *, asection *, PTR, bfd_vma, bfd_size_type));

static boolean nlm_i386_read_import

  PARAMS ((bfd *, nlmNAME(symbol_type) *));

static boolean nlm_i386_write_external

  PARAMS ((bfd *, bfd_size_type, asymbol *, struct reloc_and_sec *));

/* Adjust the reloc location by an absolute value.  */

static reloc_howto_type nlm_i386_abs_howto =

  HOWTO (0,                      /* type */

         0,                      /* rightshift */

         2,                     /* size (0 = byte, 1 = short, 2 = long) */

         32,                    /* bitsize */

         false,                 /* pc_relative */

         0,                      /* bitpos */

         complain_overflow_bitfield, /* complain_on_overflow */

         0,                      /* special_function */

         "32",                  /* name */

         true,                  /* partial_inplace */

         0xffffffff,            /* src_mask */

         0xffffffff,            /* dst_mask */

         false);                /* pcrel_offset */

/* Adjust the reloc location by a PC relative displacement.  */

static reloc_howto_type nlm_i386_pcrel_howto =

  HOWTO (1,                     /* type */

         0,                      /* rightshift */

         2,                     /* size (0 = byte, 1 = short, 2 = long) */

         32,                    /* bitsize */

         true,                  /* pc_relative */

         0,                      /* bitpos */

         complain_overflow_signed, /* complain_on_overflow */

         0,                      /* special_function */

         "DISP32",              /* name */

         true,                  /* partial_inplace */

         0xffffffff,            /* src_mask */

         0xffffffff,            /* dst_mask */

         true);                 /* pcrel_offset */

/* Read a NetWare i386 reloc.  */

static boolean

nlm_i386_read_reloc (abfd, sym, secp, rel)

     bfd *abfd;

     nlmNAME(symbol_type) *sym;

     asection **secp;

     arelent *rel;

{

  bfd_byte temp[4];

  bfd_vma val;

  const char *name;

  if (bfd_read (temp, sizeof (temp), 1, abfd) != sizeof (temp))

    return false;

  val = bfd_get_32 (abfd, temp);

  /* The value is an offset into either the code or data segment.

     This is the location which needs to be adjusted.

     If this is a relocation fixup rather than an imported symbol (the

     sym argument is NULL) then the high bit is 0 if the location

     needs to be adjusted by the address of the data segment, or 1 if

     the location needs to be adjusted by the address of the code

     segment.  If this is an imported symbol, then the high bit is 0

     if the location is 0 if the location should be adjusted by the

     offset to the symbol, or 1 if the location should adjusted by the

     absolute value of the symbol.

     The second most significant bit is 0 if the value is an offset

     into the data segment, or 1 if the value is an offset into the

     code segment.

     All this translates fairly easily into a BFD reloc.  */

  if (sym == NULL)

    {

      if ((val & NLM_HIBIT) == 0)

        name = NLM_INITIALIZED_DATA_NAME;

      else

        {

          name = NLM_CODE_NAME;

          val &=~ NLM_HIBIT;

        }

      rel->sym_ptr_ptr = bfd_get_section_by_name (abfd, name)->symbol_ptr_ptr;

      rel->howto = &nlm_i386_abs_howto;

    }

  else

    {

      /* In this case we do not need to set the sym_ptr_ptr field.  */

      rel->sym_ptr_ptr = NULL;

      if ((val & NLM_HIBIT) == 0)

        rel->howto = &nlm_i386_pcrel_howto;

      else

        {

          rel->howto = &nlm_i386_abs_howto;

          val &=~ NLM_HIBIT;

        }

    }

  if ((val & (NLM_HIBIT >> 1)) == 0)

    *secp = bfd_get_section_by_name (abfd, NLM_INITIALIZED_DATA_NAME);

  else

    {

      *secp = bfd_get_section_by_name (abfd, NLM_CODE_NAME);

      val &=~ (NLM_HIBIT >> 1);

    }

  rel->address = val;

  rel->addend = 0;

  return true;

}

/* Write a NetWare i386 reloc.  */

static boolean

nlm_i386_write_import (abfd, sec, rel)

     bfd *abfd;

     asection *sec;

     arelent *rel;

{

  asymbol *sym;

  bfd_vma val;

  bfd_byte temp[4];

  /* NetWare only supports two kinds of relocs.  We should check

     special_function here, as well, but at the moment coff-i386

     relocs uses a special_function which does not affect what we do

     here.  */

  if (rel->addend != 0

      || rel->howto == NULL

      || rel->howto->rightshift != 0

      || rel->howto->size != 2

      || rel->howto->bitsize != 32

      || rel->howto->bitpos != 0

      || rel->howto->src_mask != 0xffffffff

      || rel->howto->dst_mask != 0xffffffff)

    {

      bfd_set_error (bfd_error_invalid_operation);

      return false;

    }

  sym = *rel->sym_ptr_ptr;

  /* The value we write out is the offset into the appropriate

     segment.  This offset is the section vma, adjusted by the vma of

     the lowest section in that segment, plus the address of the

     relocation.  */

  val = bfd_get_section_vma (abfd, sec) + rel->address;

  /* The second most significant bit is 0 if the value is an offset

     into the data segment, or 1 if the value is an offset into the

     code segment.  */

  if (bfd_get_section_flags (abfd, sec) & SEC_CODE)

    {

      val -= nlm_get_text_low (abfd);

      val |= NLM_HIBIT >> 1;

    }

  else

    val -= nlm_get_data_low (abfd);

  if (! bfd_is_und_section (bfd_get_section (sym)))

    {

      /* NetWare only supports absolute internal relocs.  */

      if (rel->howto->pc_relative)

        {

          bfd_set_error (bfd_error_invalid_operation);

          return false;

        }

      /* The high bit is 1 if the reloc is against the code section, 0

         if against the data section.  */

      if (bfd_get_section_flags (abfd, bfd_get_section (sym)) & SEC_CODE)

        val |= NLM_HIBIT;

    }

  else

    {

      /* The high bit is 1 if this is an absolute reloc, 0 if it is PC

         relative.  */

      if (! rel->howto->pc_relative)

        val |= NLM_HIBIT;

      else

        {

          /* PC relative relocs on NetWare must be pcrel_offset.  */

          if (! rel->howto->pcrel_offset)

            {

              bfd_set_error (bfd_error_invalid_operation);

              return false;

            }

        }

    }

  bfd_put_32 (abfd, val, temp);

  if (bfd_write (temp, sizeof (temp), 1, abfd) != sizeof (temp))

    return false;

  return true;

}

/* I want to be able to use objcopy to turn a i386 a.out or COFF file

   into a NetWare i386 module.  That means that the relocs from the

   source file have to be mapped into relocs that apply to the target

   file.  This function is called by nlm_set_section_contents to give

   it a chance to rework the relocs.

   This is actually a fairly general concept.  However, this is not a

   general implementation.  */

static boolean

nlm_i386_mangle_relocs (abfd, sec, data, offset, count)

     bfd *abfd;

     asection *sec;

     PTR data;

     bfd_vma offset;

     bfd_size_type count;

{

  arelent **rel_ptr_ptr, **rel_end;

  rel_ptr_ptr = sec->orelocation;

  rel_end = rel_ptr_ptr + sec->reloc_count;

  for (; rel_ptr_ptr < rel_end; rel_ptr_ptr++)

    {

      arelent *rel;

      asymbol *sym;

      bfd_vma addend;

      rel = *rel_ptr_ptr;

      sym = *rel->sym_ptr_ptr;

      /* Note that no serious harm will ensue if we fail to change a

         reloc.  We will wind up failing in nlm_i386_write_import.  */

      /* Make sure this reloc is within the data we have.  We only 4

         byte relocs here, so we insist on having 4 bytes.  */

      if (rel->address < offset

          || rel->address + 4 > offset + count)

        continue;

      /* NetWare doesn't support reloc addends, so we get rid of them

         here by simply adding them into the object data.  We handle

         the symbol value, if any, the same way.  */

      addend = rel->addend + sym->value;

      /* The value of a symbol is the offset into the section.  If the

         symbol is in the .bss segment, we need to include the size of

         the data segment in the offset as well.  Fortunately, we know

         that at this point the size of the data section is in the NLM

         header.  */

      if (((bfd_get_section_flags (abfd, bfd_get_section (sym))

            & SEC_LOAD) == 0)

          && ((bfd_get_section_flags (abfd, bfd_get_section (sym))

               & SEC_ALLOC) != 0))

        addend += nlm_fixed_header (abfd)->dataImageSize;

      if (addend != 0

          && rel->howto != NULL

          && rel->howto->rightshift == 0

          && rel->howto->size == 2

          && rel->howto->bitsize == 32

          && rel->howto->bitpos == 0

          && rel->howto->src_mask == 0xffffffff

          && rel->howto->dst_mask == 0xffffffff)

        {

          bfd_vma val;

          val = bfd_get_32 (abfd, (bfd_byte *) data + rel->address - offset);

          val += addend;

          bfd_put_32 (abfd, val, (bfd_byte *) data + rel->address - offset);

          rel->addend = 0;

        }

      /* NetWare uses a reloc with pcrel_offset set.  We adjust

         pc_relative relocs accordingly.  We are going to change the

         howto field, so we can only do this if the current one is

         compatible.  We should check special_function here, but at

         the moment coff-i386 uses a special_function which does not

         affect what we are doing here.  */

      if (rel->howto != NULL

          && rel->howto->pc_relative

          && ! rel->howto->pcrel_offset

          && rel->howto->rightshift == 0

          && rel->howto->size == 2

          && rel->howto->bitsize == 32

          && rel->howto->bitpos == 0

          && rel->howto->src_mask == 0xffffffff

          && rel->howto->dst_mask == 0xffffffff)

        {

          bfd_vma val;

          /* When pcrel_offset is not set, it means that the negative

             of the address of the memory location is stored in the

             memory location.  We must add it back in.  */

          val = bfd_get_32 (abfd, (bfd_byte *) data + rel->address - offset);

          val += rel->address;

          bfd_put_32 (abfd, val, (bfd_byte *) data + rel->address - offset);

          rel->howto = &nlm_i386_pcrel_howto;

        }

    }

  return true;

}

/* Read a NetWare i386 import record */

static boolean

nlm_i386_read_import (abfd, sym)

     bfd *abfd;

     nlmNAME(symbol_type) *sym;

{

  struct nlm_relent *nlm_relocs;        /* relocation records for symbol */

  bfd_size_type rcount;                 /* number of relocs */

  bfd_byte temp[NLM_TARGET_LONG_SIZE];  /* temporary 32-bit value */

  unsigned char symlength;              /* length of symbol name */

  char *name;

  if (bfd_read ((PTR) &symlength, sizeof (symlength), 1, abfd)

      != sizeof (symlength))

    return false;

  sym -> symbol.the_bfd = abfd;

  name = bfd_alloc (abfd, symlength + 1);

  if (name == NULL)

    return false;

  if (bfd_read (name, symlength, 1, abfd) != symlength)

    return false;

  name[symlength] = '\0';

  sym -> symbol.name = name;

  sym -> symbol.flags = 0;

  sym -> symbol.value = 0;

  sym -> symbol.section = bfd_und_section_ptr;

  if (bfd_read ((PTR) temp, sizeof (temp), 1, abfd) != sizeof (temp))

    return false;

  rcount = bfd_h_get_32 (abfd, temp);

  nlm_relocs = ((struct nlm_relent *)

                bfd_alloc (abfd, rcount * sizeof (struct nlm_relent)));

  if (!nlm_relocs)

    return false;

  sym -> relocs = nlm_relocs;

  sym -> rcnt = 0;

  while (sym -> rcnt < rcount)

    {

      asection *section;

      if (nlm_i386_read_reloc (abfd, sym, &section,

                               &nlm_relocs -> reloc)

          == false)

        return false;

      nlm_relocs -> section = section;

      nlm_relocs++;

      sym -> rcnt++;

    }

  return true;

}

/* Write out an external reference.  */

static boolean

nlm_i386_write_external (abfd, count, sym, relocs)

     bfd *abfd;

     bfd_size_type count;

     asymbol *sym;

     struct reloc_and_sec *relocs;

{

  unsigned int i;

  bfd_byte len;

  unsigned char temp[NLM_TARGET_LONG_SIZE];

  len = strlen (sym->name);

  if ((bfd_write (&len, sizeof (bfd_byte), 1, abfd) != sizeof(bfd_byte))

      || bfd_write (sym->name, len, 1, abfd) != len)

    return false;

  bfd_put_32 (abfd, count, temp);

  if (bfd_write (temp, sizeof(temp), 1, abfd) != sizeof (temp))

    return false;

  for (i = 0; i < count; i++)

    {

      if (nlm_i386_write_import (abfd, relocs[i].sec,

                                 relocs[i].rel) == false)

        return false;

    }

  return true;

}

#include "nlmswap.h"

static const struct nlm_backend_data nlm32_i386_backend =

{

  "NetWare Loadable Module\032",

  sizeof (Nlm32_i386_External_Fixed_Header),

  0,     /* optional_prefix_size */

  bfd_arch_i386,

  0,

  false,

  0,     /* backend_object_p */

  0,     /* write_prefix_func */

  nlm_i386_read_reloc,

  nlm_i386_mangle_relocs,

  nlm_i386_read_import,

  nlm_i386_write_import,

  0,     /* set_public_section */

  0,     /* get_public_offset */

  nlm_swap_fixed_header_in,

  nlm_swap_fixed_header_out,

  nlm_i386_write_external,

  0,     /* write_export */

};

#define TARGET_LITTLE_NAME              "nlm32-i386"

#define TARGET_LITTLE_SYM               nlmNAME(i386_vec)

#define TARGET_BACKEND_DATA             &nlm32_i386_backend

#include "nlm-target.h"