425 lines
13 KiB
C
425 lines
13 KiB
C
/* BFD back-end for Intel 386 COFF files (DJGPP variant with a stub).
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Copyright (C) 1997-2016 Free Software Foundation, Inc.
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Written by Robert Hoehne.
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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 3 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., 51 Franklin Street - Fifth Floor, Boston,
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MA 02110-1301, USA. */
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/* This file handles now also stubbed coff images. The stub is a small
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DOS executable program before the coff image to load it in memory
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and execute it. This is needed, because DOS cannot run coff files.
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All the functions below are called by the corresponding functions
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from coffswap.h.
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The only thing what they do is to adjust the information stored in
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the COFF file which are offset into the file.
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This is needed, because DJGPP uses a very special way to load and run
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the coff image. It loads the image in memory and assumes then, that the
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image had no stub by using the filepointers as pointers in the coff
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image and NOT in the file.
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To be compatible with any existing executables I have fixed this
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here and NOT in the DJGPP startup code. */
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#define TARGET_SYM i386_coff_go32stubbed_vec
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#define TARGET_NAME "coff-go32-exe"
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#define TARGET_UNDERSCORE '_'
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#define COFF_GO32_EXE
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#define COFF_LONG_SECTION_NAMES
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#define COFF_SUPPORT_GNU_LINKONCE
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#define COFF_LONG_FILENAMES
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#define COFF_SECTION_ALIGNMENT_ENTRIES \
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{ COFF_SECTION_NAME_EXACT_MATCH (".data"), \
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COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 4 }, \
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{ COFF_SECTION_NAME_EXACT_MATCH (".text"), \
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COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 4 }, \
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{ COFF_SECTION_NAME_PARTIAL_MATCH (".debug"), \
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COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 0 }, \
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{ COFF_SECTION_NAME_PARTIAL_MATCH (".gnu.linkonce.wi"), \
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COFF_ALIGNMENT_FIELD_EMPTY, COFF_ALIGNMENT_FIELD_EMPTY, 0 }
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#include "sysdep.h"
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#include "bfd.h"
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/* All that ..._PRE and ...POST functions are called from the corresponding
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coff_swap... functions. The ...PRE functions are called at the beginning
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of the function and the ...POST functions at the end of the swap routines. */
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static void
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adjust_filehdr_in_post (bfd *, void *, void *);
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static void
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adjust_filehdr_out_pre (bfd *, void *, void *);
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static void
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adjust_filehdr_out_post (bfd *, void *, void *);
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static void
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adjust_scnhdr_in_post (bfd *, void *, void *);
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static void
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adjust_scnhdr_out_pre (bfd *, void *, void *);
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static void
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adjust_scnhdr_out_post (bfd *, void *, void *);
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static void
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adjust_aux_in_post (bfd *, void *, int, int, int, int, void *);
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static void
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adjust_aux_out_pre (bfd *, void *, int, int, int, int, void *);
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static void
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adjust_aux_out_post (bfd *, void *, int, int, int, int, void *);
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static void
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create_go32_stub (bfd *);
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#define COFF_ADJUST_FILEHDR_IN_POST adjust_filehdr_in_post
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#define COFF_ADJUST_FILEHDR_OUT_PRE adjust_filehdr_out_pre
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#define COFF_ADJUST_FILEHDR_OUT_POST adjust_filehdr_out_post
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#define COFF_ADJUST_SCNHDR_IN_POST adjust_scnhdr_in_post
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#define COFF_ADJUST_SCNHDR_OUT_PRE adjust_scnhdr_out_pre
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#define COFF_ADJUST_SCNHDR_OUT_POST adjust_scnhdr_out_post
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#define COFF_ADJUST_AUX_IN_POST adjust_aux_in_post
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#define COFF_ADJUST_AUX_OUT_PRE adjust_aux_out_pre
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#define COFF_ADJUST_AUX_OUT_POST adjust_aux_out_post
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static const bfd_target *go32_check_format (bfd *);
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#define COFF_CHECK_FORMAT go32_check_format
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static bfd_boolean
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go32_stubbed_coff_bfd_copy_private_bfd_data (bfd *, bfd *);
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#define coff_bfd_copy_private_bfd_data go32_stubbed_coff_bfd_copy_private_bfd_data
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#include "coff-i386.c"
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/* This macro is used, because I cannot assume the endianness of the
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host system. */
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#define _H(index) (H_GET_16 (abfd, (header + index * 2)))
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/* These bytes are a 2048-byte DOS executable, which loads the COFF
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image into memory and then runs it. It is called 'stub'. */
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static const unsigned char stub_bytes[GO32_STUBSIZE] =
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{
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#include "go32stub.h"
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};
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/*
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I have not commented each swap function below, because the
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technique is in any function the same. For the ...in function,
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all the pointers are adjusted by adding GO32_STUBSIZE and for the
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...out function, it is subtracted first and after calling the
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standard swap function it is reset to the old value. */
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/* This macro is used for adjusting the filepointers, which
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is done only, if the pointer is nonzero. */
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#define ADJUST_VAL(val,diff) \
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if (val != 0) val += diff
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static void
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adjust_filehdr_in_post (bfd * abfd ATTRIBUTE_UNUSED,
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void * src,
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void * dst)
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{
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FILHDR *filehdr_src = (FILHDR *) src;
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struct internal_filehdr *filehdr_dst = (struct internal_filehdr *) dst;
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ADJUST_VAL (filehdr_dst->f_symptr, GO32_STUBSIZE);
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/* Save now the stub to be used later. Put the stub data to FILEHDR_DST
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first as coff_data (abfd) still does not exist. It may not even be ever
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created as we are just checking the file format of ABFD. */
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memcpy (filehdr_dst->go32stub, filehdr_src->stub, GO32_STUBSIZE);
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filehdr_dst->f_flags |= F_GO32STUB;
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}
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static void
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adjust_filehdr_out_pre (bfd * abfd, void * in, void * out)
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{
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struct internal_filehdr *filehdr_in = (struct internal_filehdr *) in;
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FILHDR *filehdr_out = (FILHDR *) out;
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/* Generate the stub. */
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create_go32_stub (abfd);
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/* Copy the stub to the file header. */
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if (coff_data (abfd)->go32stub != NULL)
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memcpy (filehdr_out->stub, coff_data (abfd)->go32stub, GO32_STUBSIZE);
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else
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/* Use the default. */
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memcpy (filehdr_out->stub, stub_bytes, GO32_STUBSIZE);
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ADJUST_VAL (filehdr_in->f_symptr, -GO32_STUBSIZE);
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}
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static void
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adjust_filehdr_out_post (bfd * abfd ATTRIBUTE_UNUSED,
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void * in,
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void * out ATTRIBUTE_UNUSED)
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{
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struct internal_filehdr *filehdr_in = (struct internal_filehdr *) in;
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/* Undo the above change. */
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ADJUST_VAL (filehdr_in->f_symptr, GO32_STUBSIZE);
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}
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static void
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adjust_scnhdr_in_post (bfd * abfd ATTRIBUTE_UNUSED,
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void * ext ATTRIBUTE_UNUSED,
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void * in)
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{
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struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;
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ADJUST_VAL (scnhdr_int->s_scnptr, GO32_STUBSIZE);
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ADJUST_VAL (scnhdr_int->s_relptr, GO32_STUBSIZE);
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ADJUST_VAL (scnhdr_int->s_lnnoptr, GO32_STUBSIZE);
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}
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static void
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adjust_scnhdr_out_pre (bfd * abfd ATTRIBUTE_UNUSED,
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void * in,
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void * out ATTRIBUTE_UNUSED)
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{
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struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;
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ADJUST_VAL (scnhdr_int->s_scnptr, -GO32_STUBSIZE);
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ADJUST_VAL (scnhdr_int->s_relptr, -GO32_STUBSIZE);
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ADJUST_VAL (scnhdr_int->s_lnnoptr, -GO32_STUBSIZE);
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}
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static void
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adjust_scnhdr_out_post (bfd * abfd ATTRIBUTE_UNUSED,
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void * in,
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void * out ATTRIBUTE_UNUSED)
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{
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struct internal_scnhdr *scnhdr_int = (struct internal_scnhdr *) in;
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ADJUST_VAL (scnhdr_int->s_scnptr, GO32_STUBSIZE);
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ADJUST_VAL (scnhdr_int->s_relptr, GO32_STUBSIZE);
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ADJUST_VAL (scnhdr_int->s_lnnoptr, GO32_STUBSIZE);
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}
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static void
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adjust_aux_in_post (bfd * abfd ATTRIBUTE_UNUSED,
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void * ext1 ATTRIBUTE_UNUSED,
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int type,
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int in_class,
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int indx ATTRIBUTE_UNUSED,
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int numaux ATTRIBUTE_UNUSED,
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void * in1)
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{
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union internal_auxent *in = (union internal_auxent *) in1;
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if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type)
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|| ISTAG (in_class))
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{
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ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, GO32_STUBSIZE);
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}
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}
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static void
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adjust_aux_out_pre (bfd *abfd ATTRIBUTE_UNUSED,
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void * inp,
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int type,
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int in_class,
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int indx ATTRIBUTE_UNUSED,
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int numaux ATTRIBUTE_UNUSED,
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void * extp ATTRIBUTE_UNUSED)
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{
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union internal_auxent *in = (union internal_auxent *) inp;
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if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type)
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|| ISTAG (in_class))
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{
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ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, -GO32_STUBSIZE);
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}
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}
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static void
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adjust_aux_out_post (bfd *abfd ATTRIBUTE_UNUSED,
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void * inp,
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int type,
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int in_class,
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int indx ATTRIBUTE_UNUSED,
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int numaux ATTRIBUTE_UNUSED,
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void * extp ATTRIBUTE_UNUSED)
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{
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union internal_auxent *in = (union internal_auxent *) inp;
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if (in_class == C_BLOCK || in_class == C_FCN || ISFCN (type)
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|| ISTAG (in_class))
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{
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ADJUST_VAL (in->x_sym.x_fcnary.x_fcn.x_lnnoptr, GO32_STUBSIZE);
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}
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}
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/* That's the function, which creates the stub. There are
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different cases from where the stub is taken.
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At first the environment variable $(GO32STUB) is checked and then
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$(STUB) if it was not set.
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If it exists and points to a valid stub the stub is taken from
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that file. This file can be also a whole executable file, because
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the stub is computed from the exe information at the start of that
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file.
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If there was any error, the standard stub (compiled in this file)
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is taken. */
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static void
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create_go32_stub (bfd *abfd)
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{
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/* Do it only once. */
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if (coff_data (abfd)->go32stub == NULL)
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{
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char *stub;
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struct stat st;
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int f;
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unsigned char header[10];
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char magic[8];
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unsigned long coff_start;
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long exe_start;
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/* Check at first the environment variable $(GO32STUB). */
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stub = getenv ("GO32STUB");
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/* Now check the environment variable $(STUB). */
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if (stub == NULL)
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stub = getenv ("STUB");
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if (stub == NULL)
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goto stub_end;
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if (stat (stub, &st) != 0)
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goto stub_end;
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#ifdef O_BINARY
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f = open (stub, O_RDONLY | O_BINARY);
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#else
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f = open (stub, O_RDONLY);
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#endif
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if (f < 0)
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goto stub_end;
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if (read (f, &header, sizeof (header)) < 0)
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{
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close (f);
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goto stub_end;
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}
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if (_H (0) != 0x5a4d) /* It is not an exe file. */
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{
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close (f);
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goto stub_end;
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}
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/* Compute the size of the stub (it is every thing up
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to the beginning of the coff image). */
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coff_start = (long) _H (2) * 512L;
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if (_H (1))
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coff_start += (long) _H (1) - 512L;
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/* Currently there is only a fixed stub size of 2048 bytes
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supported. */
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if (coff_start != 2048)
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{
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close (f);
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goto stub_end;
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}
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exe_start = _H (4) * 16;
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if ((long) lseek (f, exe_start, SEEK_SET) != exe_start)
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{
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close (f);
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goto stub_end;
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}
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if (read (f, &magic, 8) != 8)
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{
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close (f);
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goto stub_end;
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}
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if (! CONST_STRNEQ (magic, "go32stub"))
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{
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close (f);
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goto stub_end;
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}
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/* Now we found a correct stub (hopefully). */
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coff_data (abfd)->go32stub = bfd_alloc (abfd, (bfd_size_type) coff_start);
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if (coff_data (abfd)->go32stub == NULL)
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{
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close (f);
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return;
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}
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lseek (f, 0L, SEEK_SET);
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if ((unsigned long) read (f, coff_data (abfd)->go32stub, coff_start)
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!= coff_start)
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{
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bfd_release (abfd, coff_data (abfd)->go32stub);
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coff_data (abfd)->go32stub = NULL;
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}
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close (f);
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}
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stub_end:
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/* There was something wrong above, so use now the standard builtin
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stub. */
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if (coff_data (abfd)->go32stub == NULL)
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{
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coff_data (abfd)->go32stub
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= bfd_alloc (abfd, (bfd_size_type) GO32_STUBSIZE);
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if (coff_data (abfd)->go32stub == NULL)
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return;
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memcpy (coff_data (abfd)->go32stub, stub_bytes, GO32_STUBSIZE);
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}
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}
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/* If ibfd was a stubbed coff image, copy the stub from that bfd
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to the new obfd. */
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static bfd_boolean
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go32_stubbed_coff_bfd_copy_private_bfd_data (bfd *ibfd, bfd *obfd)
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{
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/* Check if both are the same targets. */
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if (ibfd->xvec != obfd->xvec)
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return TRUE;
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/* Check if we have a source stub. */
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if (coff_data (ibfd)->go32stub == NULL)
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return TRUE;
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/* As adjust_filehdr_out_pre may get called only after this function,
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optionally allocate the output stub. */
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if (coff_data (obfd)->go32stub == NULL)
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coff_data (obfd)->go32stub = bfd_alloc (obfd,
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(bfd_size_type) GO32_STUBSIZE);
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/* Now copy the stub. */
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if (coff_data (obfd)->go32stub != NULL)
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memcpy (coff_data (obfd)->go32stub, coff_data (ibfd)->go32stub,
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GO32_STUBSIZE);
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return TRUE;
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}
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/* coff_object_p only checks 2 bytes F_MAGIC at GO32_STUBSIZE inside the file
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which is too fragile. */
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static const bfd_target *
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go32_check_format (bfd *abfd)
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{
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char mz[2];
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if (bfd_bread (mz, 2, abfd) != 2 || mz[0] != 'M' || mz[1] != 'Z')
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{
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bfd_set_error (bfd_error_wrong_format);
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return NULL;
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}
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if (bfd_seek (abfd, 0, SEEK_SET) != 0)
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return NULL;
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return coff_object_p (abfd);
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}
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