355 lines
10 KiB
C
355 lines
10 KiB
C
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/* Support for 32-bit i386 NLM (NetWare Loadable Module)
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Copyright (C) 1993 Free Software Foundation, Inc.
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This file is part of BFD, the Binary File Descriptor library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include "bfd.h"
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#include "sysdep.h"
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#include "libbfd.h"
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#define ARCH_SIZE 32
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#include "libnlm.h"
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static boolean nlm_i386_read_reloc
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PARAMS ((bfd *, nlmNAME(symbol_type) *, asection **, arelent *));
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static boolean nlm_i386_write_reloc
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PARAMS ((bfd *, asection *, arelent *));
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static boolean nlm_i386_mangle_relocs
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PARAMS ((bfd *, asection *, PTR, bfd_vma, bfd_size_type));
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/* Adjust the reloc location by an absolute value. */
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static reloc_howto_type nlm_i386_abs_howto =
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HOWTO (0, /* type */
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0, /* rightshift */
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2, /* size (0 = byte, 1 = short, 2 = long) */
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32, /* bitsize */
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false, /* pc_relative */
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0, /* bitpos */
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complain_overflow_bitfield, /* complain_on_overflow */
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0, /* special_function */
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"32", /* name */
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true, /* partial_inplace */
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0xffffffff, /* src_mask */
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0xffffffff, /* dst_mask */
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false); /* pcrel_offset */
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/* Adjust the reloc location by a PC relative displacement. */
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static reloc_howto_type nlm_i386_pcrel_howto =
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HOWTO (1, /* type */
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0, /* rightshift */
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2, /* size (0 = byte, 1 = short, 2 = long) */
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32, /* bitsize */
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true, /* pc_relative */
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0, /* bitpos */
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complain_overflow_signed, /* complain_on_overflow */
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0, /* special_function */
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"DISP32", /* name */
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true, /* partial_inplace */
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0xffffffff, /* src_mask */
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0xffffffff, /* dst_mask */
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true); /* pcrel_offset */
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/* Read a NetWare i386 reloc. */
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static boolean
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nlm_i386_read_reloc (abfd, sym, secp, rel)
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bfd *abfd;
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nlmNAME(symbol_type) *sym;
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asection **secp;
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arelent *rel;
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{
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bfd_byte temp[4];
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bfd_vma val;
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const char *name;
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if (bfd_read (temp, sizeof (temp), 1, abfd) != sizeof (temp))
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{
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bfd_error = system_call_error;
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return false;
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}
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val = bfd_get_32 (abfd, temp);
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/* The value is an offset into either the code or data segment.
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This is the location which needs to be adjusted.
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If this is a relocation fixup rather than an imported symbol (the
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sym argument is NULL) then the high bit is 0 if the location
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needs to be adjusted by the address of the data segment, or 1 if
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the location needs to be adjusted by the address of the code
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segment. If this is an imported symbol, then the high bit is 0
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if the location is 0 if the location should be adjusted by the
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offset to the symbol, or 1 if the location should adjusted by the
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absolute value of the symbol.
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The second most significant bit is 0 if the value is an offset
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into the data segment, or 1 if the value is an offset into the
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code segment.
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All this translates fairly easily into a BFD reloc. */
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if (sym == NULL)
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{
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if ((val & NLM_HIBIT) == 0)
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name = NLM_INITIALIZED_DATA_NAME;
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else
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{
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name = NLM_CODE_NAME;
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val &=~ NLM_HIBIT;
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}
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rel->sym_ptr_ptr = bfd_get_section_by_name (abfd, name)->symbol_ptr_ptr;
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rel->howto = &nlm_i386_abs_howto;
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}
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else
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{
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/* In this case we do not need to set the sym_ptr_ptr field. */
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rel->sym_ptr_ptr = NULL;
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if ((val & NLM_HIBIT) == 0)
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rel->howto = &nlm_i386_pcrel_howto;
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else
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{
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rel->howto = &nlm_i386_abs_howto;
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val &=~ NLM_HIBIT;
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}
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}
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if ((val & (NLM_HIBIT >> 1)) == 0)
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*secp = bfd_get_section_by_name (abfd, NLM_INITIALIZED_DATA_NAME);
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else
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{
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*secp = bfd_get_section_by_name (abfd, NLM_CODE_NAME);
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val &=~ (NLM_HIBIT >> 1);
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}
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rel->address = val;
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rel->addend = 0;
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return true;
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}
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/* Write a NetWare i386 reloc. */
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static boolean
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nlm_i386_write_reloc (abfd, sec, rel)
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bfd *abfd;
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asection *sec;
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arelent *rel;
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{
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asymbol *sym;
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bfd_vma val;
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bfd_byte temp[4];
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/* NetWare only supports two kinds of relocs. We should check
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special_function here, as well, but at the moment coff-i386
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relocs uses a special_function which does not affect what we do
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here. */
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if (rel->addend != 0
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|| rel->howto == NULL
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|| rel->howto->rightshift != 0
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|| rel->howto->size != 2
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|| rel->howto->bitsize != 32
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|| rel->howto->bitpos != 0
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|| ! rel->howto->partial_inplace
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|| rel->howto->src_mask != 0xffffffff
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|| rel->howto->dst_mask != 0xffffffff)
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{
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bfd_error = invalid_operation;
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return false;
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}
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sym = *rel->sym_ptr_ptr;
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/* The value we write out is the offset into the appropriate
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segment. This offset is the section vma, adjusted by the vma of
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the lowest section in that segment, plus the address of the
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relocation. */
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val = bfd_get_section_vma (abfd, sec) + rel->address;
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/* The second most significant bit is 0 if the value is an offset
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into the data segment, or 1 if the value is an offset into the
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code segment. */
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if (bfd_get_section_flags (abfd, sec) & SEC_CODE)
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{
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val -= nlm_get_text_low (abfd);
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val |= NLM_HIBIT >> 1;
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}
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else
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val -= nlm_get_data_low (abfd);
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if (bfd_get_section (sym) != &bfd_und_section)
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{
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/* NetWare only supports absolute internal relocs. */
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if (rel->howto->pc_relative)
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{
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bfd_error = invalid_operation;
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return false;
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}
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/* The high bit is 1 if the reloc is against the code section, 0
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if against the data section. */
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if (bfd_get_section_flags (abfd, bfd_get_section (sym)) & SEC_CODE)
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val |= NLM_HIBIT;
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}
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else
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{
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/* The high bit is 1 if this is an absolute reloc, 0 if it is PC
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relative. */
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if (! rel->howto->pc_relative)
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val |= NLM_HIBIT;
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else
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{
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/* PC relative relocs on NetWare must be pcrel_offset. */
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if (! rel->howto->pcrel_offset)
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{
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bfd_error = invalid_operation;
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return false;
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}
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}
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}
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bfd_put_32 (abfd, val, temp);
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if (bfd_write (temp, sizeof (temp), 1, abfd) != sizeof (temp))
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{
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bfd_error = system_call_error;
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return false;
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}
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return true;
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}
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/* I want to be able to use objcopy to turn a i386 a.out or COFF file
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into a NetWare i386 module. That means that the relocs from the
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source file have to be mapped into relocs that apply to the target
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file. This function is called by nlm_set_section_contents to give
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it a chance to rework the relocs.
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This is actually a fairly general concept. However, this is not a
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general implementation. */
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static boolean
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nlm_i386_mangle_relocs (abfd, sec, data, offset, count)
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bfd *abfd;
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asection *sec;
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PTR data;
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bfd_vma offset;
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bfd_size_type count;
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{
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arelent **rel_ptr_ptr, **rel_end;
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rel_ptr_ptr = sec->orelocation;
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rel_end = rel_ptr_ptr + sec->reloc_count;
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for (; rel_ptr_ptr < rel_end; rel_ptr_ptr++)
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{
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arelent *rel;
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asymbol *sym;
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bfd_vma addend;
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rel = *rel_ptr_ptr;
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sym = *rel->sym_ptr_ptr;
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/* Note that no serious harm will ensue if we fail to change a
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reloc. We will wind up failing in nlm_i386_write_reloc. */
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/* Make sure this reloc is within the data we have. We only 4
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byte relocs here, so we insist on having 4 bytes. */
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if (rel->address < offset
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|| rel->address + 4 > offset + count)
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continue;
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/* NetWare doesn't support reloc addends, so we get rid of them
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here by simply adding them into the object data. We handle
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the symbol value, if any, the same way. */
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addend = rel->addend + sym->value;
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/* The value of a symbol is the offset into the section. If the
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symbol is in the .bss segment, we need to include the size of
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the data segment in the offset as well. Fortunately, we know
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that at this point the size of the data section is in the NLM
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header. */
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if (((bfd_get_section_flags (abfd, bfd_get_section (sym))
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& (SEC_CODE | SEC_DATA)) == 0)
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&& ((bfd_get_section_flags (abfd, bfd_get_section (sym))
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& SEC_ALLOC) != 0))
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addend += nlm_fixed_header (abfd)->dataImageSize;
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if (addend != 0
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&& rel->howto != NULL
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&& rel->howto->rightshift == 0
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&& rel->howto->size == 2
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&& rel->howto->bitsize == 32
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&& rel->howto->bitpos == 0
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&& rel->howto->partial_inplace
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&& rel->howto->src_mask == 0xffffffff
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&& rel->howto->dst_mask == 0xffffffff)
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{
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bfd_vma val;
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val = bfd_get_32 (abfd, (char *) data + rel->address - offset);
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val += addend;
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bfd_put_32 (abfd, val, (char *) data + rel->address - offset);
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rel->addend = 0;
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}
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/* NetWare uses a reloc with pcrel_offset set. We adjust
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pc_relative relocs accordingly. We are going to change the
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howto field, so we can only do this if the current one is
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compatible. We should check special_function here, but at
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the moment coff-i386 uses a special_function which does not
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affect what we are doing here. */
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if (rel->howto != NULL
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&& rel->howto->pc_relative
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&& ! rel->howto->pcrel_offset
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&& rel->howto->rightshift == 0
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&& rel->howto->size == 2
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&& rel->howto->bitsize == 32
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&& rel->howto->bitpos == 0
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&& rel->howto->partial_inplace
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&& rel->howto->src_mask == 0xffffffff
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&& rel->howto->dst_mask == 0xffffffff)
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{
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bfd_vma val;
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/* When pcrel_offset is not set, it means that the negative
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of the address of the memory location is stored in the
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memory location. We must add it back in. */
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val = bfd_get_32 (abfd, (char *) data + rel->address - offset);
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val += rel->address;
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bfd_put_32 (abfd, val, (char *) data + rel->address - offset);
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rel->howto = &nlm_i386_pcrel_howto;
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}
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}
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return true;
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}
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static const struct nlm_backend_data nlm32_i386_backend =
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{
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bfd_arch_i386,
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nlm_i386_read_reloc,
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nlm_i386_write_reloc,
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nlm_i386_mangle_relocs
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};
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#define TARGET_LITTLE_NAME "nlm32-i386"
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#define TARGET_LITTLE_SYM nlmNAME(i386_vec)
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#define TARGET_BACKEND_DATA &nlm32_i386_backend
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#include "nlm-target.h"
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