path: root/src/unexapollo.c

/* unexapollo.c -- COFF File UNEXEC for GNU Emacs on Apollo SR10.x
   Copyright (C) 1988, 1994, 2002, 2003, 2004,
                 2005, 2006 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs 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, or (at your option)
any later version.

GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */

/* Written by Leonard N. Zubkoff.  */

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

#include <fcntl.h>


#include <a.out.h>
#include <sys/file.h>
#include <apollo/base.h>
#include <apollo/ios.h>
#include <apollo/type_uids.h>
#include <apollo/dst.h>


#define DST_RECORD_HDR_SIZE	2
#define LONG_ALIGN(X)		(((X)+3)&(~3))


void
unexec (target_file_name, source_file_name)
     char *target_file_name, *source_file_name;
{
  struct filehdr file_header;
  struct aouthdr domain_header;
  struct scnhdr *section, *sections, *sections_limit;
  struct scnhdr *first_data_section, *last_data_section;
  struct scnhdr *rwdi_section, *blocks_section;
  struct reloc reloc_entry;
  unsigned long data_size, old_data_section_size, source_file_offset_past_rwdi;
  unsigned char buffer[4096];
  long delta_before_rwdi, delta_after_rwdi, byte_count;
  long first_changed_vaddr, old_rwdi_vaddr, i;
  ios_$id_t target_file, source_file;
  status_$t status;
  /* Open the Source File. */
  if ((source_file = open (source_file_name, O_RDONLY)) < 0)
    error ("cannot open source file for input");
  /* Read the File Header. */
  if (read (source_file, &file_header, sizeof (file_header)) != sizeof (file_header))
    error ("cannot read file header");
  
  /* Read the Domain Header. */
  if (read (source_file, &domain_header, sizeof (domain_header))
      != sizeof (domain_header))
    error ("cannot read domain header");
  /* Read the Section Headers. */
  sections =
    (struct scnhdr *) malloc (file_header.f_nscns*sizeof (struct scnhdr));
  if (sections == (struct scnhdr *) 0)
    error ("cannot allocate section header storage");
  sections_limit = sections + file_header.f_nscns;
  if (read (source_file, sections, file_header.f_nscns*sizeof (struct scnhdr))
      != file_header.f_nscns*sizeof (struct scnhdr))
    error ("cannot read section headers");
  /* Compute the new Size of the Data Section. */
  data_size = sbrk (0) - domain_header.data_start;
  delta_before_rwdi = delta_after_rwdi = data_size - domain_header.dsize;
  old_rwdi_vaddr = 0;
  /* Find and Deallocate the .rwdi Section Information. */
  for (rwdi_section = sections; rwdi_section != sections_limit; rwdi_section++)
    if (strcmp (rwdi_section->s_name, ".rwdi") == 0)
      {
	/* If there are relocation entries, we cannot "unrelocate" them. */
	if (rwdi_section->s_nreloc > 0)
	  error (".rwdi section needs relocation - cannot dump Emacs");
	delta_after_rwdi = delta_before_rwdi - rwdi_section->s_size;
	old_rwdi_vaddr = rwdi_section->s_vaddr;
	rwdi_section->s_paddr = 0;
	rwdi_section->s_vaddr = 0;
	rwdi_section->s_scnptr = 0;
	rwdi_section->s_size = 0;
	source_file_offset_past_rwdi = (rwdi_section+1)->s_scnptr;
	break;
      }
  /* Skip over the Text Section Headers. */
  for (section = sections; (section->s_flags & STYP_TEXT) != 0; section++) ;
  /*
    Find the First and Last Data Sections and Fixup
    Section Header Relocation Pointers.
    */
  first_data_section = last_data_section = (struct scnhdr *) 0;
  for (; section != sections_limit; section++)
    {
      if ((section->s_flags & STYP_DATA) != 0)
	{
	  if (first_data_section == (struct scnhdr *) 0)
	    first_data_section = section;
	  last_data_section = section;
	}
      if (section->s_relptr != 0)
	section->s_relptr += delta_after_rwdi;
    }
  /* Increment the Size of the Last Data Section. */
  old_data_section_size = last_data_section->s_size;
  last_data_section->s_size += delta_before_rwdi;
  
  /* Update the File Header and Domain Header. */
  file_header.f_symptr += delta_after_rwdi;
  domain_header.dsize = data_size;
  domain_header.bsize = 0;
  /* Skip over subsequent Bss Section Headers. */
  for (section = last_data_section+1;
       (section->s_flags & STYP_BSS) != 0; section++) ;
  /* Update the remaining Section Headers. */
  blocks_section = (struct scnhdr *) 0;
  first_changed_vaddr = 0;
  for (; section != sections_limit; section++)
    {
      long delta = (section < rwdi_section ? delta_before_rwdi : delta_after_rwdi);
      if (section->s_paddr != 0)
	section->s_paddr += delta;
      if (section->s_vaddr != 0)
	{
	  if (first_changed_vaddr == 0)
	    first_changed_vaddr = section->s_vaddr;
	  section->s_vaddr += delta;
	}
      if (section->s_scnptr != 0)
	section->s_scnptr += delta;
      if (strcmp (section->s_name, ".blocks") == 0)
	blocks_section = section;
      else if (strcmp (section->s_name, ".sri") == 0 &&
	       domain_header.o_sri != 0)
	domain_header.o_sri += delta;
      else if (strcmp (section->s_name, ".inlib") == 0 &&
	       domain_header.o_inlib != 0)
	domain_header.o_inlib += delta;
    }
  /* Open the Target File. */
  ios_$create (target_file_name, strlen (target_file_name), coff_$uid,
	       ios_$recreate_mode, ios_$write_opt, &target_file, &status);
  if (status.all != status_$ok)
    error ("cannot open target file for output");
  /* Write the File Header. */
  if (write (target_file, &file_header, sizeof (file_header)) != sizeof (file_header))
    error ("cannot write file header");
  /* Write the Domain Header. */
  if (write (target_file, &domain_header, sizeof (domain_header))
      != sizeof (domain_header))
    error ("cannot write domain header");
  /* Write the Section Headers. */
  if (write (target_file, sections, file_header.f_nscns*sizeof (struct scnhdr))
      != file_header.f_nscns*sizeof (struct scnhdr))
    error ("cannot write section headers");
  /* Copy the Allocated Sections. */
  for (section = sections; section != first_data_section; section++)
    if (section->s_scnptr != 0)
      CopyData (target_file, source_file, LONG_ALIGN(section->s_size));
  /* Write the Expanded Data Segment. */
  if (write (target_file, first_data_section->s_vaddr, data_size) != data_size)
    error ("cannot write new data section");
  
  /* Skip over the Last Data Section and Copy until the .rwdi Section. */
  if (lseek (source_file, last_data_section->s_scnptr
	     +old_data_section_size, L_SET) == -1)
    error ("cannot seek past data section");
  for (section = last_data_section+1; section != rwdi_section; section++)
    if (section->s_scnptr != 0)
      CopyData (target_file, source_file, LONG_ALIGN(section->s_size));
  /* Skip over the .rwdi Section and Copy Remainder of Source File. */
  if (lseek (source_file, source_file_offset_past_rwdi, L_SET) == -1)
    error ("cannot seek past .rwdi section");
  while ((byte_count = read (source_file, buffer, sizeof (buffer))) > 0)
    if (write (target_file, buffer, byte_count) != byte_count)
      error ("cannot write data");
  /* Unrelocate .data references to Global Symbols. */
  for (section = first_data_section; section <= last_data_section; section++)
    for (i = 0; i < section->s_nreloc; i++)
      {
	if  (lseek (source_file, section->s_relptr
		    +i*sizeof (struct reloc)-delta_after_rwdi, L_SET) == -1)
	  error ("cannot seek to relocation info");
	if (read (source_file, &reloc_entry, sizeof (reloc_entry))
	    != sizeof (reloc_entry))
	  error ("cannot read reloc entry");
	if (lseek (source_file, reloc_entry.r_vaddr-section->s_vaddr
		   +section->s_scnptr, L_SET) == -1)
	  error ("cannot seek to data element");
	if (lseek (target_file, reloc_entry.r_vaddr-section->s_vaddr
		   +section->s_scnptr, L_SET) == -1)
	  error ("cannot seek to data element");
	if (read (source_file, buffer, 4) != 4)
	  error ("cannot read data element");
	if (write (target_file, buffer, 4) != 4)
	  error ("cannot write data element");
      }
  
  /* Correct virtual addresses in .blocks section. */
  if (blocks_section != (struct scnhdr *) 0)
    {
      dst_rec_t dst_record;
      dst_rec_comp_unit_t *comp_unit;
      unsigned short number_of_sections;
      unsigned long section_base;
      unsigned long section_offset = 0;
      /* Find section tables and update section base addresses. */
      while (section_offset < blocks_section->s_size)
	{
	  if (lseek (target_file,
		     blocks_section->s_scnptr+section_offset, L_SET) == -1)
	    error ("cannot seek to comp unit record");
	  /* Handle pad records before the comp unit record. */
	  if (read (target_file, &dst_record, DST_RECORD_HDR_SIZE)
	      != DST_RECORD_HDR_SIZE)
	    error ("cannot read dst record tag");
	  if (dst_record.rec_type == dst_typ_pad)
	    section_offset += DST_RECORD_HDR_SIZE;
	  else if (dst_record.rec_type == dst_typ_comp_unit)
	    {
	      comp_unit = &dst_record.rec_data.comp_unit_;
	      if  (read (target_file, comp_unit, sizeof (*comp_unit))
		   != sizeof (*comp_unit))
		error ("cannot read comp unit record");
	      if (lseek (target_file, blocks_section->s_scnptr
			 +section_offset
#if dst_version_major == 1 && dst_version_minor < 4
			 +comp_unit->section_table
#else
			 +comp_unit->section_table.rel_offset
#endif
			 +DST_RECORD_HDR_SIZE,
			 L_SET) == -1)
		error ("cannot seek to section table");
	      if (read (target_file, &number_of_sections, sizeof (number_of_sections))
		  != sizeof (number_of_sections))
		error ("cannot read section table size");
	      for (i = 0; i < number_of_sections; i++)
		{
		  if (read (target_file, &section_base, sizeof (section_base))
		      != sizeof (section_base))
		    error ("cannot read section base value");
		  if (section_base < first_changed_vaddr)
		    continue;
		  else if (section_base < old_rwdi_vaddr)
		    section_base += delta_before_rwdi;
		  else section_base += delta_after_rwdi;
		  if (lseek (target_file, -sizeof (section_base), L_INCR) == -1)
		    error ("cannot seek to section base value");
		  if (write (target_file, &section_base, sizeof (section_base))
		      != sizeof (section_base))
		    error ("cannot write section base");
		}
	      section_offset += comp_unit->data_size;
	    }
	  else error ("unexpected dst record type");
	}
    }
  
  if (close (source_file) == -1)
    error("cannot close source file");
  if (close (target_file) == -1)
    error ("cannot close target file");
}


static
CopyData (target_file, source_file, total_byte_count)
     int target_file, source_file;
     long total_byte_count;
{
  unsigned char buffer[4096];
  long byte_count;
  while (total_byte_count > 0)
    {
      if (total_byte_count > sizeof (buffer))
	byte_count = sizeof (buffer);
      else byte_count = total_byte_count;
      if (read (source_file, buffer, byte_count) != byte_count)
	error ("cannot read data");
      if (write (target_file, buffer, byte_count) != byte_count)
	error ("cannot write data");
      total_byte_count -= byte_count;
    }
}

/* arch-tag: 783ebbdf-7d26-4df8-9469-17a1747dce96
   (do not change this comment) */