libiberty/simple-object.c - rust-lang/gcc - Git at Google

 /* simple-object.c -- simple routines to read and write object files.
    Copyright (C) 2010-2018 Free Software Foundation, Inc.
    Written by Ian Lance Taylor, Google.

 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, 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, 51 Franklin Street - Fifth Floor,
 Boston, MA 02110-1301, USA.  */

 #include "config.h"
 #include "libiberty.h"
 #include "simple-object.h"

 #include <errno.h>
 #include <fcntl.h>

 #ifdef HAVE_STDLIB_H
 #include <stdlib.h>
 #endif

 #ifdef HAVE_STDINT_H
 #include <stdint.h>
 #endif

 #ifdef HAVE_STRING_H
 #include <string.h>
 #endif

 #ifdef HAVE_INTTYPES_H
 #include <inttypes.h>
 #endif

 #ifndef SEEK_SET
 #define SEEK_SET 0
 #endif

 #include "simple-object-common.h"

 /* The known object file formats.  */

 static const struct simple_object_functions * const format_functions[] =
 {
   &simple_object_elf_functions,
   &simple_object_mach_o_functions,
   &simple_object_coff_functions,
   &simple_object_xcoff_functions
 };

 /* Read data from a file using the simple_object error reporting
    conventions.  */

 int
 simple_object_internal_read (int descriptor, off_t offset,
 			     unsigned char *buffer, size_t size,
 			     const char **errmsg, int *err)
 {
   if (lseek (descriptor, offset, SEEK_SET) < 0)
     {
       *errmsg = "lseek";
       *err = errno;
       return 0;
     }

   do
     {
       ssize_t got = read (descriptor, buffer, size);
       if (got == 0)
 	break;
       else if (got > 0)
 	{
 	  buffer += got;
 	  size -= got;
 	}
       else if (errno != EINTR)
 	{
 	  *errmsg = "read";
 	  *err = errno;
 	  return 0;
 	}
     }
   while (size > 0);

   if (size > 0)
     {
       *errmsg = "file too short";
       *err = 0;
       return 0;
     }

   return 1;
 }

 /* Write data to a file using the simple_object error reporting
    conventions.  */

 int
 simple_object_internal_write (int descriptor, off_t offset,
 			      const unsigned char *buffer, size_t size,
 			      const char **errmsg, int *err)
 {
   if (lseek (descriptor, offset, SEEK_SET) < 0)
     {
       *errmsg = "lseek";
       *err = errno;
       return 0;
     }

   do
     {
       ssize_t wrote = write (descriptor, buffer, size);
       if (wrote == 0)
 	break;
       else if (wrote > 0)
 	{
 	  buffer += wrote;
 	  size -= wrote;
 	}
       else if (errno != EINTR)
 	{
 	  *errmsg = "write";
 	  *err = errno;
 	  return 0;
 	}
     }
   while (size > 0);

   if (size > 0)
     {
       *errmsg = "short write";
       *err = 0;
       return 0;
     }

   return 1;
 }

 /* Open for read.  */

 simple_object_read *
 simple_object_start_read (int descriptor, off_t offset,
 			  const char *segment_name, const char **errmsg,
 			  int *err)
 {
   unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN];
   size_t len, i;

   if (!simple_object_internal_read (descriptor, offset, header,
 				    SIMPLE_OBJECT_MATCH_HEADER_LEN,
 				    errmsg, err))
     return NULL;

   len = sizeof (format_functions) / sizeof (format_functions[0]);
   for (i = 0; i < len; ++i)
     {
       void *data;

       data = format_functions[i]->match (header, descriptor, offset,
 					 segment_name, errmsg, err);
       if (data != NULL)
 	{
 	  simple_object_read *ret;

 	  ret = XNEW (simple_object_read);
 	  ret->descriptor = descriptor;
 	  ret->offset = offset;
 	  ret->functions = format_functions[i];
 	  ret->data = data;
 	  return ret;
 	}
     }

   *errmsg = "file not recognized";
   *err = 0;
   return NULL;
 }

 /* Find all sections.  */

 const char *
 simple_object_find_sections (simple_object_read *sobj,
 			     int (*pfn) (void *, const char *, off_t, off_t),
 			     void *data,
 			     int *err)
 {
   return sobj->functions->find_sections (sobj, pfn, data, err);
 }

 /* Internal data passed to find_one_section.  */

 struct find_one_section_data
 {
   /* The section we are looking for.  */
   const char *name;
   /* Where to store the section offset.  */
   off_t *offset;
   /* Where to store the section length.  */
   off_t *length;
   /* Set if the name is found.  */
   int found;
 };

 /* Internal function passed to find_sections.  */

 static int
 find_one_section (void *data, const char *name, off_t offset, off_t length)
 {
   struct find_one_section_data *fosd = (struct find_one_section_data *) data;

   if (strcmp (name, fosd->name) != 0)
     return 1;

   *fosd->offset = offset;
   *fosd->length = length;
   fosd->found = 1;

   /* Stop iteration.  */
   return 0;
 }

 /* Find a section.  */

 int
 simple_object_find_section (simple_object_read *sobj, const char *name,
 			    off_t *offset, off_t *length,
 			    const char **errmsg, int *err)
 {
   struct find_one_section_data fosd;

   fosd.name = name;
   fosd.offset = offset;
   fosd.length = length;
   fosd.found = 0;

   *errmsg = simple_object_find_sections (sobj, find_one_section,
 					 (void *) &fosd, err);
   if (*errmsg != NULL)
     return 0;
   if (!fosd.found)
     return 0;
   return 1;
 }

 /* Callback to identify and rename LTO debug sections by name.
    Returns 1 if NAME is a LTO debug section, 0 if not.  */

 static char *
 handle_lto_debug_sections (const char *name)
 {
   char *newname = XCNEWVEC (char, strlen (name) + 1);

   /* ???  So we can't use .gnu.lto_ prefixed sections as the assembler
      complains about bogus section flags.  Which means we need to arrange
      for that to be fixed or .gnu.debuglto_ marked as SHF_EXCLUDE (to make
      fat lto object tooling work for the fat part).  */
   /* Also include corresponding reloc sections.  */
   if (strncmp (name, ".rela", sizeof (".rela") - 1) == 0)
     {
       strncpy (newname, name, sizeof (".rela") - 1);
       name += sizeof (".rela") - 1;
     }
   else if (strncmp (name, ".rel", sizeof (".rel") - 1) == 0)
     {
       strncpy (newname, name, sizeof (".rel") - 1);
       name += sizeof (".rel") - 1;
     }
   /* ???  For now this handles both .gnu.lto_ and .gnu.debuglto_ prefixed
      sections.  */
   /* Copy LTO debug sections and rename them to their non-LTO name.  */
   if (strncmp (name, ".gnu.debuglto_", sizeof (".gnu.debuglto_") - 1) == 0)
     return strcat (newname, name + sizeof (".gnu.debuglto_") - 1);
   else if (strncmp (name, ".gnu.lto_.debug_",
 		    sizeof (".gnu.lto_.debug_") -1) == 0)
     return strcat (newname, name + sizeof (".gnu.lto_") - 1);
   /* Copy over .note.GNU-stack section under the same name if present.  */
   else if (strcmp (name, ".note.GNU-stack") == 0)
     return strcpy (newname, name);
   return NULL;
 }

 /* Copy LTO debug sections.  */

 const char *
 simple_object_copy_lto_debug_sections (simple_object_read *sobj,
 				       const char *dest, int *err)
 {
   const char *errmsg;
   simple_object_write *dest_sobj;
   simple_object_attributes *attrs;
   int outfd;

   if (! sobj->functions->copy_lto_debug_sections)
     {
       *err = EINVAL;
       return "simple_object_copy_lto_debug_sections not implemented";
     }

   attrs = simple_object_fetch_attributes (sobj, &errmsg, err);
   if (! attrs)
     return errmsg;
   dest_sobj = simple_object_start_write (attrs, NULL, &errmsg, err);
   simple_object_release_attributes (attrs);
   if (! dest_sobj)
     return errmsg;

   errmsg = sobj->functions->copy_lto_debug_sections (sobj, dest_sobj,
 						     handle_lto_debug_sections,
 						     err);
   if (errmsg)
     {
       simple_object_release_write (dest_sobj);
       return errmsg;
     }

   outfd = creat (dest, 00777);
   if (outfd == -1)
     {
       *err = errno;
       simple_object_release_write (dest_sobj);
       return "open failed";
     }

   errmsg = simple_object_write_to_file (dest_sobj, outfd, err);
   close (outfd);
   if (errmsg)
     {
       simple_object_release_write (dest_sobj);
       return errmsg;
     }

   simple_object_release_write (dest_sobj);
   return NULL;
 }

 /* Fetch attributes.  */

 simple_object_attributes *
 simple_object_fetch_attributes (simple_object_read *sobj, const char **errmsg,
 				int *err)
 {
   void *data;
   simple_object_attributes *ret;

   data = sobj->functions->fetch_attributes (sobj, errmsg, err);
   if (data == NULL)
     return NULL;
   ret = XNEW (simple_object_attributes);
   ret->functions = sobj->functions;
   ret->data = data;
   return ret;
 }

 /* Release an simple_object_read.  */

 void
 simple_object_release_read (simple_object_read *sobj)
 {
   sobj->functions->release_read (sobj->data);
   XDELETE (sobj);
 }

 /* Merge attributes.  */

 const char *
 simple_object_attributes_merge (simple_object_attributes *to,
 				simple_object_attributes *from,
 				int *err)
 {
   if (to->functions != from->functions)
     {
       *err = 0;
       return "different object file format";
     }
   return to->functions->attributes_merge (to->data, from->data, err);
 }

 /* Release an attributes structure.  */

 void
 simple_object_release_attributes (simple_object_attributes *attrs)
 {
   attrs->functions->release_attributes (attrs->data);
   XDELETE (attrs);
 }

 /* Start creating an object file.  */

 simple_object_write *
 simple_object_start_write (simple_object_attributes *attrs,
 			   const char *segment_name, const char **errmsg,
 			   int *err)
 {
   void *data;
   simple_object_write *ret;

   data = attrs->functions->start_write (attrs->data, errmsg, err);
   if (data == NULL)
     return NULL;
   ret = XNEW (simple_object_write);
   ret->functions = attrs->functions;
   ret->segment_name = segment_name ? xstrdup (segment_name) : NULL;
   ret->sections = NULL;
   ret->last_section = NULL;
   ret->data = data;
   return ret;
 }

 /* Start creating a section.  */

 simple_object_write_section *
 simple_object_write_create_section (simple_object_write *sobj, const char *name,
 				    unsigned int align,
 				    const char **errmsg ATTRIBUTE_UNUSED,
 				    int *err ATTRIBUTE_UNUSED)
 {
   simple_object_write_section *ret;

   ret = XNEW (simple_object_write_section);
   ret->next = NULL;
   ret->name = xstrdup (name);
   ret->align = align;
   ret->buffers = NULL;
   ret->last_buffer = NULL;

   if (sobj->last_section == NULL)
     {
       sobj->sections = ret;
       sobj->last_section = ret;
     }
   else
     {
       sobj->last_section->next = ret;
       sobj->last_section = ret;
     }

   return ret;
 }

 /* Add data to a section.  */

 const char *
 simple_object_write_add_data (simple_object_write *sobj ATTRIBUTE_UNUSED,
 			      simple_object_write_section *section,
 			      const void *buffer,
 			      size_t size, int copy,
 			      int *err ATTRIBUTE_UNUSED)
 {
   struct simple_object_write_section_buffer *wsb;

   wsb = XNEW (struct simple_object_write_section_buffer);
   wsb->next = NULL;
   wsb->size = size;

   if (!copy)
     {
       wsb->buffer = buffer;
       wsb->free_buffer = NULL;
     }
   else
     {
       wsb->free_buffer = (void *) XNEWVEC (char, size);
       memcpy (wsb->free_buffer, buffer, size);
       wsb->buffer = wsb->free_buffer;
     }

   if (section->last_buffer == NULL)
     {
       section->buffers = wsb;
       section->last_buffer = wsb;
     }
   else
     {
       section->last_buffer->next = wsb;
       section->last_buffer = wsb;
     }

   return NULL;
 }

 /* Write the complete object file.  */

 const char *
 simple_object_write_to_file (simple_object_write *sobj, int descriptor,
 			     int *err)
 {
   return sobj->functions->write_to_file (sobj, descriptor, err);
 }

 /* Release an simple_object_write.  */

 void
 simple_object_release_write (simple_object_write *sobj)
 {
   simple_object_write_section *section;

   free (sobj->segment_name);

   section = sobj->sections;
   while (section != NULL)
     {
       struct simple_object_write_section_buffer *buffer;
       simple_object_write_section *next_section;

       buffer = section->buffers;
       while (buffer != NULL)
 	{
 	  struct simple_object_write_section_buffer *next_buffer;

 	  if (buffer->free_buffer != NULL)
 	    XDELETEVEC (buffer->free_buffer);
 	  next_buffer = buffer->next;
 	  XDELETE (buffer);
 	  buffer = next_buffer;
 	}

       next_section = section->next;
       free (section->name);
       XDELETE (section);
       section = next_section;
     }

   sobj->functions->release_write (sobj->data);
   XDELETE (sobj);
 }
	/* simple-object.c -- simple routines to read and write object files.
	Copyright (C) 2010-2018 Free Software Foundation, Inc.
	Written by Ian Lance Taylor, Google.

	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, 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, 51 Franklin Street - Fifth Floor,
	Boston, MA 02110-1301, USA. */

	#include "config.h"
	#include "libiberty.h"
	#include "simple-object.h"

	#include <errno.h>
	#include <fcntl.h>

	#ifdef HAVE_STDLIB_H
	#include <stdlib.h>
	#endif

	#ifdef HAVE_STDINT_H
	#include <stdint.h>
	#endif

	#ifdef HAVE_STRING_H
	#include <string.h>
	#endif

	#ifdef HAVE_INTTYPES_H
	#include <inttypes.h>
	#endif

	#ifndef SEEK_SET
	#define SEEK_SET 0
	#endif

	#include "simple-object-common.h"

	/* The known object file formats. */

	static const struct simple_object_functions * const format_functions[] =
	{
	&simple_object_elf_functions,
	&simple_object_mach_o_functions,
	&simple_object_coff_functions,
	&simple_object_xcoff_functions
	};

	/* Read data from a file using the simple_object error reporting
	conventions. */

	int
	simple_object_internal_read (int descriptor, off_t offset,
	unsigned char *buffer, size_t size,
	const char *errmsg, int err)
	{
	if (lseek (descriptor, offset, SEEK_SET) < 0)
	{
	*errmsg = "lseek";
	*err = errno;
	return 0;
	}

	do
	{
	ssize_t got = read (descriptor, buffer, size);
	if (got == 0)
	break;
	else if (got > 0)
	{
	buffer += got;
	size -= got;
	}
	else if (errno != EINTR)
	{
	*errmsg = "read";
	*err = errno;
	return 0;
	}
	}
	while (size > 0);

	if (size > 0)
	{
	*errmsg = "file too short";
	*err = 0;
	return 0;
	}

	return 1;
	}

	/* Write data to a file using the simple_object error reporting
	conventions. */

	int
	simple_object_internal_write (int descriptor, off_t offset,
	const unsigned char *buffer, size_t size,
	const char *errmsg, int err)
	{
	if (lseek (descriptor, offset, SEEK_SET) < 0)
	{
	*errmsg = "lseek";
	*err = errno;
	return 0;
	}

	do
	{
	ssize_t wrote = write (descriptor, buffer, size);
	if (wrote == 0)
	break;
	else if (wrote > 0)
	{
	buffer += wrote;
	size -= wrote;
	}
	else if (errno != EINTR)
	{
	*errmsg = "write";
	*err = errno;
	return 0;
	}
	}
	while (size > 0);

	if (size > 0)
	{
	*errmsg = "short write";
	*err = 0;
	return 0;
	}

	return 1;
	}

	/* Open for read. */

	simple_object_read *
	simple_object_start_read (int descriptor, off_t offset,
	const char segment_name, const char *errmsg,
	int *err)
	{
	unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN];
	size_t len, i;

	if (!simple_object_internal_read (descriptor, offset, header,
	SIMPLE_OBJECT_MATCH_HEADER_LEN,
	errmsg, err))
	return NULL;

	len = sizeof (format_functions) / sizeof (format_functions[0]);
	for (i = 0; i < len; ++i)
	{
	void *data;

	data = format_functions[i]->match (header, descriptor, offset,
	segment_name, errmsg, err);
	if (data != NULL)
	{
	simple_object_read *ret;

	ret = XNEW (simple_object_read);
	ret->descriptor = descriptor;
	ret->offset = offset;
	ret->functions = format_functions[i];
	ret->data = data;
	return ret;
	}
	}

	*errmsg = "file not recognized";
	*err = 0;
	return NULL;
	}

	/* Find all sections. */

	const char *
	simple_object_find_sections (simple_object_read *sobj,
	int (pfn) (void , const char *, off_t, off_t),
	void *data,
	int *err)
	{
	return sobj->functions->find_sections (sobj, pfn, data, err);
	}

	/* Internal data passed to find_one_section. */

	struct find_one_section_data
	{
	/* The section we are looking for. */
	const char *name;
	/* Where to store the section offset. */
	off_t *offset;
	/* Where to store the section length. */
	off_t *length;
	/* Set if the name is found. */
	int found;
	};

	/* Internal function passed to find_sections. */

	static int
	find_one_section (void data, const char name, off_t offset, off_t length)
	{
	struct find_one_section_data fosd = (struct find_one_section_data ) data;

	if (strcmp (name, fosd->name) != 0)
	return 1;

	*fosd->offset = offset;
	*fosd->length = length;
	fosd->found = 1;

	/* Stop iteration. */
	return 0;
	}

	/* Find a section. */

	int
	simple_object_find_section (simple_object_read sobj, const char name,
	off_t offset, off_t length,
	const char *errmsg, int err)
	{
	struct find_one_section_data fosd;

	fosd.name = name;
	fosd.offset = offset;
	fosd.length = length;
	fosd.found = 0;

	*errmsg = simple_object_find_sections (sobj, find_one_section,
	(void *) &fosd, err);
	if (*errmsg != NULL)
	return 0;
	if (!fosd.found)
	return 0;
	return 1;
	}

	/* Callback to identify and rename LTO debug sections by name.
	Returns 1 if NAME is a LTO debug section, 0 if not. */

	static char *
	handle_lto_debug_sections (const char *name)
	{
	char *newname = XCNEWVEC (char, strlen (name) + 1);

	/* ??? So we can't use .gnu.lto_ prefixed sections as the assembler
	complains about bogus section flags. Which means we need to arrange
	for that to be fixed or .gnu.debuglto_ marked as SHF_EXCLUDE (to make
	fat lto object tooling work for the fat part). */
	/* Also include corresponding reloc sections. */
	if (strncmp (name, ".rela", sizeof (".rela") - 1) == 0)
	{
	strncpy (newname, name, sizeof (".rela") - 1);
	name += sizeof (".rela") - 1;
	}
	else if (strncmp (name, ".rel", sizeof (".rel") - 1) == 0)
	{
	strncpy (newname, name, sizeof (".rel") - 1);
	name += sizeof (".rel") - 1;
	}
	/* ??? For now this handles both .gnu.lto_ and .gnu.debuglto_ prefixed
	sections. */
	/* Copy LTO debug sections and rename them to their non-LTO name. */
	if (strncmp (name, ".gnu.debuglto_", sizeof (".gnu.debuglto_") - 1) == 0)
	return strcat (newname, name + sizeof (".gnu.debuglto_") - 1);
	else if (strncmp (name, ".gnu.lto_.debug_",
	sizeof (".gnu.lto_.debug_") -1) == 0)
	return strcat (newname, name + sizeof (".gnu.lto_") - 1);
	/* Copy over .note.GNU-stack section under the same name if present. */
	else if (strcmp (name, ".note.GNU-stack") == 0)
	return strcpy (newname, name);
	return NULL;
	}

	/* Copy LTO debug sections. */

	const char *
	simple_object_copy_lto_debug_sections (simple_object_read *sobj,
	const char dest, int err)
	{
	const char *errmsg;
	simple_object_write *dest_sobj;
	simple_object_attributes *attrs;
	int outfd;

	if (! sobj->functions->copy_lto_debug_sections)
	{
	*err = EINVAL;
	return "simple_object_copy_lto_debug_sections not implemented";
	}

	attrs = simple_object_fetch_attributes (sobj, &errmsg, err);
	if (! attrs)
	return errmsg;
	dest_sobj = simple_object_start_write (attrs, NULL, &errmsg, err);
	simple_object_release_attributes (attrs);
	if (! dest_sobj)
	return errmsg;

	errmsg = sobj->functions->copy_lto_debug_sections (sobj, dest_sobj,
	handle_lto_debug_sections,
	err);
	if (errmsg)
	{
	simple_object_release_write (dest_sobj);
	return errmsg;
	}

	outfd = creat (dest, 00777);
	if (outfd == -1)
	{
	*err = errno;
	simple_object_release_write (dest_sobj);
	return "open failed";
	}

	errmsg = simple_object_write_to_file (dest_sobj, outfd, err);
	close (outfd);
	if (errmsg)
	{
	simple_object_release_write (dest_sobj);
	return errmsg;
	}

	simple_object_release_write (dest_sobj);
	return NULL;
	}

	/* Fetch attributes. */

	simple_object_attributes *
	simple_object_fetch_attributes (simple_object_read sobj, const char *errmsg,
	int *err)
	{
	void *data;
	simple_object_attributes *ret;

	data = sobj->functions->fetch_attributes (sobj, errmsg, err);
	if (data == NULL)
	return NULL;
	ret = XNEW (simple_object_attributes);
	ret->functions = sobj->functions;
	ret->data = data;
	return ret;
	}

	/* Release an simple_object_read. */

	void
	simple_object_release_read (simple_object_read *sobj)
	{
	sobj->functions->release_read (sobj->data);
	XDELETE (sobj);
	}

	/* Merge attributes. */

	const char *
	simple_object_attributes_merge (simple_object_attributes *to,
	simple_object_attributes *from,
	int *err)
	{
	if (to->functions != from->functions)
	{
	*err = 0;
	return "different object file format";
	}
	return to->functions->attributes_merge (to->data, from->data, err);
	}

	/* Release an attributes structure. */

	void
	simple_object_release_attributes (simple_object_attributes *attrs)
	{
	attrs->functions->release_attributes (attrs->data);
	XDELETE (attrs);
	}

	/* Start creating an object file. */

	simple_object_write *
	simple_object_start_write (simple_object_attributes *attrs,
	const char segment_name, const char *errmsg,
	int *err)
	{
	void *data;
	simple_object_write *ret;

	data = attrs->functions->start_write (attrs->data, errmsg, err);
	if (data == NULL)
	return NULL;
	ret = XNEW (simple_object_write);
	ret->functions = attrs->functions;
	ret->segment_name = segment_name ? xstrdup (segment_name) : NULL;
	ret->sections = NULL;
	ret->last_section = NULL;
	ret->data = data;
	return ret;
	}

	/* Start creating a section. */

	simple_object_write_section *
	simple_object_write_create_section (simple_object_write sobj, const char name,
	unsigned int align,
	const char **errmsg ATTRIBUTE_UNUSED,
	int *err ATTRIBUTE_UNUSED)
	{
	simple_object_write_section *ret;

	ret = XNEW (simple_object_write_section);
	ret->next = NULL;
	ret->name = xstrdup (name);
	ret->align = align;
	ret->buffers = NULL;
	ret->last_buffer = NULL;

	if (sobj->last_section == NULL)
	{
	sobj->sections = ret;
	sobj->last_section = ret;
	}
	else
	{
	sobj->last_section->next = ret;
	sobj->last_section = ret;
	}

	return ret;
	}

	/* Add data to a section. */

	const char *
	simple_object_write_add_data (simple_object_write *sobj ATTRIBUTE_UNUSED,
	simple_object_write_section *section,
	const void *buffer,
	size_t size, int copy,
	int *err ATTRIBUTE_UNUSED)
	{
	struct simple_object_write_section_buffer *wsb;

	wsb = XNEW (struct simple_object_write_section_buffer);
	wsb->next = NULL;
	wsb->size = size;

	if (!copy)
	{
	wsb->buffer = buffer;
	wsb->free_buffer = NULL;
	}
	else
	{
	wsb->free_buffer = (void *) XNEWVEC (char, size);
	memcpy (wsb->free_buffer, buffer, size);
	wsb->buffer = wsb->free_buffer;
	}

	if (section->last_buffer == NULL)
	{
	section->buffers = wsb;
	section->last_buffer = wsb;
	}
	else
	{
	section->last_buffer->next = wsb;
	section->last_buffer = wsb;
	}

	return NULL;
	}

	/* Write the complete object file. */

	const char *
	simple_object_write_to_file (simple_object_write *sobj, int descriptor,
	int *err)
	{
	return sobj->functions->write_to_file (sobj, descriptor, err);
	}

	/* Release an simple_object_write. */

	void
	simple_object_release_write (simple_object_write *sobj)
	{
	simple_object_write_section *section;

	free (sobj->segment_name);

	section = sobj->sections;
	while (section != NULL)
	{
	struct simple_object_write_section_buffer *buffer;
	simple_object_write_section *next_section;

	buffer = section->buffers;
	while (buffer != NULL)
	{
	struct simple_object_write_section_buffer *next_buffer;

	if (buffer->free_buffer != NULL)
	XDELETEVEC (buffer->free_buffer);
	next_buffer = buffer->next;
	XDELETE (buffer);
	buffer = next_buffer;
	}

	next_section = section->next;
	free (section->name);
	XDELETE (section);
	section = next_section;
	}

	sobj->functions->release_write (sobj->data);
	XDELETE (sobj);
	}