mach-o.c   [plain text]

#include "mach-o.h"

#include "bfd.h"
#include "sysdep.h"
#include "libbfd.h"
#include "libiberty.h"

#include <ctype.h>

#define bfd_mach_o_core_file_failing_command _bfd_nocore_core_file_failing_command
#define bfd_mach_o_core_file_failing_signal _bfd_nocore_core_file_failing_signal
#define bfd_mach_o_core_file_matches_executable_p _bfd_nocore_core_file_matches_executable_p

#define bfd_mach_o_mkarchive _bfd_noarchive_mkarchive
#define bfd_mach_o_read_ar_hdr _bfd_noarchive_read_ar_hdr
#define bfd_mach_o_slurp_armap _bfd_noarchive_slurp_armap
#define bfd_mach_o_slurp_extended_name_table _bfd_noarchive_slurp_extended_name_table
#define bfd_mach_o_construct_extended_name_table _bfd_noarchive_construct_extended_name_table
#define bfd_mach_o_truncate_arname _bfd_noarchive_truncate_arname
#define bfd_mach_o_write_armap _bfd_noarchive_write_armap
#define bfd_mach_o_get_elt_at_index _bfd_noarchive_get_elt_at_index
#define bfd_mach_o_generic_stat_arch_elt _bfd_noarchive_generic_stat_arch_elt
#define bfd_mach_o_update_armap_timestamp _bfd_noarchive_update_armap_timestamp

#define	bfd_mach_o_close_and_cleanup _bfd_generic_close_and_cleanup
#define bfd_mach_o_bfd_free_cached_info _bfd_generic_bfd_free_cached_info
#define bfd_mach_o_new_section_hook _bfd_generic_new_section_hook
#define bfd_mach_o_get_section_contents_in_window _bfd_generic_get_section_contents_in_window

#define bfd_mach_o_bfd_is_local_label_name _bfd_nosymbols_bfd_is_local_label_name
#define bfd_mach_o_get_lineno _bfd_nosymbols_get_lineno
#define bfd_mach_o_find_nearest_line _bfd_nosymbols_find_nearest_line
#define bfd_mach_o_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
#define bfd_mach_o_read_minisymbols _bfd_generic_read_minisymbols
#define bfd_mach_o_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol

#define bfd_mach_o_get_reloc_upper_bound _bfd_norelocs_get_reloc_upper_bound
#define bfd_mach_o_canonicalize_reloc _bfd_norelocs_canonicalize_reloc
#define bfd_mach_o_bfd_reloc_type_lookup _bfd_norelocs_bfd_reloc_type_lookup

#define bfd_mach_o_bfd_get_relocated_section_contents bfd_generic_get_relocated_section_contents
#define bfd_mach_o_bfd_relax_section bfd_generic_relax_section
#define bfd_mach_o_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
#define bfd_mach_o_bfd_link_hash_table_free _bfd_generic_link_hash_table_free
#define bfd_mach_o_bfd_link_add_symbols _bfd_generic_link_add_symbols
#define bfd_mach_o_bfd_final_link _bfd_generic_final_link
#define bfd_mach_o_bfd_link_split_section _bfd_generic_link_split_section

#define bfd_mach_o_set_arch_mach bfd_default_set_arch_mach

#define bfd_mach_o_bfd_merge_private_bfd_data _bfd_generic_bfd_merge_private_bfd_data
#define bfd_mach_o_bfd_set_private_flags _bfd_generic_bfd_set_private_flags
#define bfd_mach_o_bfd_print_private_bfd_data _bfd_generic_bfd_print_private_bfd_data

#define bfd_mach_o_get_section_contents _bfd_generic_get_section_contents
#define bfd_mach_o_set_section_contents _bfd_generic_set_section_contents

#define bfd_mach_o_bfd_gc_sections bfd_generic_gc_sections
#define bfd_mach_o_bfd_merge_sections bfd_generic_merge_sections

static asymbol *bfd_mach_o_make_empty_symbol PARAMS ((bfd *));
static int bfd_mach_o_sizeof_headers PARAMS ((bfd *, boolean));
static long bfd_mach_o_get_symtab_upper_bound PARAMS ((bfd *abfd));
static long bfd_mach_o_get_symtab PARAMS ((bfd *abfd, asymbol **alocation));
static int bfd_mach_o_scan_write_symtab PARAMS ((bfd *abfd, bfd_mach_o_load_command *command));
static int bfd_mach_o_scan_write_segment PARAMS ((bfd *abfd, bfd_mach_o_load_command *command));
static int bfd_mach_o_scan_write_thread PARAMS ((bfd *abfd, bfd_mach_o_load_command *command));
static int bfd_mach_o_write_header PARAMS ((bfd *abfd, bfd_mach_o_header *header));

/*
 * The flags field of a section structure is separated into two parts a section
 * type and section attributes.  The section types are mutually exclusive (it
 * can only have one type) but the section attributes are not (it may have more
 * than one attribute).
 */

#define SECTION_TYPE             0x000000ff     /* 256 section types */
#define SECTION_ATTRIBUTES       0xffffff00     /*  24 section attributes */

/* Constants for the section attributes part of the flags field of a section
   structure. */

#define SECTION_ATTRIBUTES_USR   0xff000000     /* user-settable attributes */
#define S_ATTR_PURE_INSTRUCTIONS 0x80000000     /* section contains only true machine instructions */
#define SECTION_ATTRIBUTES_SYS   0x00ffff00     /* system setable attributes */
#define S_ATTR_SOME_INSTRUCTIONS 0x00000400     /* section contains some machine instructions */
#define S_ATTR_EXT_RELOC         0x00000200     /* section has external relocation entries */
#define S_ATTR_LOC_RELOC         0x00000100     /* section has local relocation entries */

#define N_STAB 0xe0
#define N_TYPE 0x1e
#define N_EXT 0x01
#define N_UNDF 0x0
#define N_ABS 0x2
#define N_SECT 0xe
#define N_INDR 0xa

boolean
bfd_mach_o_valid (abfd)
     bfd *abfd;
{
  if (abfd == NULL) { return 0; }
  if (abfd->xvec == NULL) { return 0; }
  if (! ((abfd->xvec == &mach_o_be_vec) || (abfd->xvec == &mach_o_le_vec) || (abfd->xvec == &mach_o_fat_vec))) { return 0; }
  if (abfd->tdata.mach_o_data == NULL) { return 0; }
  return 1;
}

/* Copy any private info we understand from the input symbol
   to the output symbol.  */

static boolean
bfd_mach_o_bfd_copy_private_symbol_data (ibfd, isymbol, obfd, osymbol)
     bfd *ibfd;
     asymbol *isymbol;
     bfd *obfd;
     asymbol *osymbol;
{
  return true;
}

/* Copy any private info we understand from the input section
   to the output section.  */

static boolean
bfd_mach_o_bfd_copy_private_section_data (ibfd, isection, obfd, osection)
     bfd *ibfd;
     asection *isection;
     bfd *obfd;
     asection *osection;
{
  return true;
}

/* Copy any private info we understand from the input bfd
   to the output bfd.  */

static boolean
bfd_mach_o_bfd_copy_private_bfd_data (ibfd, obfd)
     bfd *ibfd;
     bfd *obfd;
{
  BFD_ASSERT (bfd_mach_o_valid (ibfd));
  BFD_ASSERT (bfd_mach_o_valid (obfd));

  obfd->tdata.mach_o_data = ibfd->tdata.mach_o_data;
  obfd->tdata.mach_o_data->ibfd = ibfd;
  return true;
}

static long
bfd_mach_o_count_symbols (abfd)
     bfd *abfd;
{
  bfd_mach_o_data_struct *mdata = NULL;
  long nsyms = 0;
  unsigned long i;
  
  BFD_ASSERT (bfd_mach_o_valid (abfd));
  mdata = abfd->tdata.mach_o_data;

  for (i = 0; i < mdata->header.ncmds; i++) {
    if (mdata->commands[i].type == BFD_MACH_O_LC_SYMTAB) {
      bfd_mach_o_symtab_command *sym = &mdata->commands[i].command.symtab;
      nsyms += sym->nsyms;
    }
  }

  return nsyms;
}

static long
bfd_mach_o_get_symtab_upper_bound (abfd)
     bfd *abfd;
{
  long nsyms = bfd_mach_o_count_symbols (abfd);
  if (nsyms < 0) { return nsyms; }
  return ((nsyms + 1) * sizeof (asymbol *));
}

static long
bfd_mach_o_get_symtab (abfd, alocation)
     bfd *abfd;
     asymbol **alocation;
{
  bfd_mach_o_data_struct *mdata = abfd->tdata.mach_o_data;
  long nsyms = bfd_mach_o_count_symbols (abfd);
  asymbol **csym = alocation;
  unsigned long i, j;

  if (nsyms < 0) { return nsyms; }

  for (i = 0; i < mdata->header.ncmds; i++) {
    if (mdata->commands[i].type == BFD_MACH_O_LC_SYMTAB) {
      bfd_mach_o_symtab_command *sym = &mdata->commands[i].command.symtab;
      if (bfd_mach_o_scan_read_symtab_symbols (abfd, &mdata->commands[i].command.symtab) != 0) { 
	fprintf (stderr, "bfd_mach_o_get_symtab: unable to load symbols for section %lu\n", i);
	return 0; 
      }
      BFD_ASSERT (sym->symbols != NULL);
      for (j = 0; j < sym->nsyms; j++) {
	BFD_ASSERT (csym < (alocation + nsyms));
	*csym++ = &sym->symbols[j];
      }
    }
  }
  *csym++ = NULL;
  
  return nsyms;
}

static void
bfd_mach_o_get_symbol_info (abfd, symbol, ret)
     bfd *abfd;
     asymbol *symbol;
     symbol_info *ret;
{
  bfd_symbol_info (symbol, ret);
}

static void
bfd_mach_o_print_symbol (abfd, afile, symbol, how)
     bfd *abfd;
     PTR afile;
     asymbol *symbol;
     bfd_print_symbol_type how;
{
  FILE *file = (FILE *) afile;
  switch (how) {
  case bfd_print_symbol_name:
    fprintf (file, "%s", symbol->name);
    break;
  default:
    bfd_print_symbol_vandf (abfd, (PTR) file, symbol);
    fprintf (file, " %-5s %s", symbol->section->name, symbol->name);
  }
}

static void bfd_mach_o_convert_architecture (mtype, msubtype, type, subtype)
     bfd_mach_o_cpu_type mtype;
     bfd_mach_o_cpu_subtype msubtype;
     enum bfd_architecture *type;
     enum bfd_architecture *subtype;
{
  *subtype = bfd_arch_unknown;

  switch (mtype) {
  case BFD_MACH_O_CPU_TYPE_VAX: *type = bfd_arch_vax; break;
  case BFD_MACH_O_CPU_TYPE_MC680x0: *type = bfd_arch_m68k; break;
  case BFD_MACH_O_CPU_TYPE_I386: *type = bfd_arch_i386; break;
  case BFD_MACH_O_CPU_TYPE_MIPS: *type = bfd_arch_mips; break;
  case BFD_MACH_O_CPU_TYPE_MC98000: *type = bfd_arch_m98k; break;
  case BFD_MACH_O_CPU_TYPE_HPPA: *type = bfd_arch_hppa; break;
  case BFD_MACH_O_CPU_TYPE_ARM: *type = bfd_arch_arm; break;
  case BFD_MACH_O_CPU_TYPE_MC88000: *type = bfd_arch_m88k; break;
  case BFD_MACH_O_CPU_TYPE_SPARC: *type = bfd_arch_sparc; break;
  case BFD_MACH_O_CPU_TYPE_I860: *type = bfd_arch_i860; break;
  case BFD_MACH_O_CPU_TYPE_ALPHA: *type = bfd_arch_alpha; break;
  case BFD_MACH_O_CPU_TYPE_POWERPC: *type = bfd_arch_powerpc; break;
  default: *type = bfd_arch_unknown; break;
  }

  switch (*type) {
  case bfd_arch_i386: *subtype = bfd_mach_i386_i386; break;
  case bfd_arch_sparc: *subtype = bfd_mach_sparc; break;
  default:
    *subtype = bfd_arch_unknown;
  }
}
  
static boolean
bfd_mach_o_write_contents (abfd)
     bfd *abfd;
{
  unsigned int i;

  bfd_mach_o_data_struct *mdata = abfd->tdata.mach_o_data;

  if (mdata->ibfd == NULL) { return false; }

  /* write data sections first in case they overlap header data to be
     written later */

  {
    char buf[1024];
    bfd *ibfd = mdata->ibfd;

    bfd_seek (ibfd, 0, SEEK_SET);
    bfd_seek (abfd, 0, SEEK_SET);
    
    for (;;) {

      bfd_size_type nread = bfd_bread ((PTR) buf, 1024, ibfd);
      if (nread == 0) { break; }
      /* FIXME: how to check for error from read? */
      
      if (bfd_bwrite ((PTR) buf, nread, abfd) != nread) { return false; }
    }
  }

#if 0
  for (i = 0; i < mdata->header.ncmds; i++) { 

    bfd_mach_o_load_command *cur = &mdata->commands[i];
    if (cur->type != BFD_MACH_O_LC_SEGMENT) { break; }

    {
      bfd_mach_o_segment_command *seg = &cur->command.segment;
      char buf[1024];
      bfd *ibfd = mdata->ibfd;
      bfd_vma nbytes = seg->filesize;
      bfd_vma curoff = seg->fileoff;
    
      while (nbytes > 0) {

	bfd_vma thisread = nbytes;
	if (thisread > 1024) { thisread = 1024; }

	bfd_seek (ibfd, curoff, SEEK_SET);
	if (bfd_bread ((PTR) buf, thisread, ibfd) != thisread) { return false; }

	bfd_seek (abfd, curoff, SEEK_SET);
	if (bfd_bwrite ((PTR) buf, thisread, abfd) != thisread) { return false; }

	nbytes -= thisread;
	curoff += thisread;
      }
    }
  }
#endif

  /* now write header information */
    
  if (bfd_mach_o_write_header (abfd, &mdata->header) != 0) {
    return false;
  } 

  for (i = 0; i < mdata->header.ncmds; i++) {

    unsigned char buf[8];
    bfd_mach_o_load_command *cur = &mdata->commands[i];

    bfd_h_put_32 (abfd, cur->type, buf);
    bfd_h_put_32 (abfd, cur->len, buf + 4);

    bfd_seek (abfd, cur->offset, SEEK_SET);
    if (bfd_bwrite ((PTR) buf, 8, abfd) != 8) { return false; }

    switch (cur->type) {
    case BFD_MACH_O_LC_SEGMENT:
      if (bfd_mach_o_scan_write_segment (abfd, cur) != 0) { return false; }
      break;
    case BFD_MACH_O_LC_SYMTAB:
      if (bfd_mach_o_scan_write_symtab (abfd, cur) != 0) { return false; }
      break;
    case BFD_MACH_O_LC_SYMSEG:
      break;
    case BFD_MACH_O_LC_THREAD:
    case BFD_MACH_O_LC_UNIXTHREAD:
      if (bfd_mach_o_scan_write_thread (abfd, cur) != 0) { return false; }
      break;
    case BFD_MACH_O_LC_LOADFVMLIB:
    case BFD_MACH_O_LC_IDFVMLIB:
    case BFD_MACH_O_LC_IDENT:
    case BFD_MACH_O_LC_FVMFILE:
    case BFD_MACH_O_LC_PREPAGE:
    case BFD_MACH_O_LC_DYSYMTAB:
    case BFD_MACH_O_LC_LOAD_DYLIB:
    case BFD_MACH_O_LC_ID_DYLIB:
    case BFD_MACH_O_LC_LOAD_DYLINKER:
    case BFD_MACH_O_LC_ID_DYLINKER:
    case BFD_MACH_O_LC_PREBOUND_DYLIB:
    case BFD_MACH_O_LC_ROUTINES:
    case BFD_MACH_O_LC_SUB_FRAMEWORK:
      break;
    default:
      fprintf (stderr, "unable to write unknown load command 0x%lx\n", (long) cur->type);
      return false;
    }
  } 

  return true;
}

static int
bfd_mach_o_sizeof_headers (a, b)
     bfd *a;
     boolean b;
{
  return 0;
}

/* Make an empty symbol.  This is required only because
   bfd_make_section_anyway wants to create a symbol for the section.  */

static asymbol *
bfd_mach_o_make_empty_symbol (abfd)
     bfd *abfd;
{
  asymbol *new;

  new = (asymbol *) bfd_zalloc (abfd, sizeof (asymbol));
  if (new == NULL) { return new; }
  new->the_bfd = abfd;
  return new;
}

static int
bfd_mach_o_write_header (abfd, header)
     bfd *abfd;
     bfd_mach_o_header *header;
{
  unsigned char buf[28];

  bfd_h_put_32 (abfd, header->magic, buf + 0);
  bfd_h_put_32 (abfd, header->cputype, buf + 4);
  bfd_h_put_32 (abfd, header->cpusubtype, buf + 8);
  bfd_h_put_32 (abfd, header->filetype, buf + 12);
  bfd_h_put_32 (abfd, header->ncmds, buf + 16);
  bfd_h_put_32 (abfd, header->sizeofcmds, buf + 20);
  bfd_h_put_32 (abfd, header->flags, buf + 24);
      
  bfd_seek (abfd, 0, SEEK_SET);
  if (bfd_bwrite ((PTR) buf, 28, abfd) != 28) { return -1; }

  return 0;
}

static int
bfd_mach_o_read_header (abfd, header)
     bfd *abfd;
     bfd_mach_o_header *header;
{
  unsigned char buf[28];
  bfd_vma (*get32) PARAMS ((const bfd_byte *)) = NULL;

  bfd_seek (abfd, 0, SEEK_SET);

  if (bfd_bread ((PTR) buf, 28, abfd) != 28) { return -1; }

  if (bfd_getb32 (buf) == 0xfeedface) {
    header->byteorder = BFD_ENDIAN_BIG;
    header->magic = 0xfeedface;
    get32 = bfd_getb32;
  } else if (bfd_getl32 (buf) == 0xfeedface) {
    header->byteorder = BFD_ENDIAN_LITTLE; 
    header->magic = 0xfeedface;
    get32 = bfd_getl32;
  } else {
    header->byteorder = BFD_ENDIAN_UNKNOWN;
    return -1;
  }
      
  header->cputype = (*get32) (buf + 4);
  header->cpusubtype = (*get32) (buf + 8);
  header->filetype = (*get32) (buf + 12);
  header->ncmds = (*get32) (buf + 16);
  header->sizeofcmds = (*get32) (buf + 20);
  header->flags = (*get32) (buf + 24);

  return 0;
}

static asection *
bfd_mach_o_make_bfd_section (abfd, section)
     bfd *abfd;
     bfd_mach_o_section *section;
{
  asection *bfdsec;
  char *sname;

  const char *prefix = "LC_SEGMENT";
  unsigned int snamelen = strlen (prefix) + 1 + strlen (section->segname) + 1 + strlen (section->sectname) + 1;

  sname = (char *) bfd_alloc (abfd, snamelen);
  if (sname == NULL) { return NULL; }
  sprintf (sname, "%s.%s.%s", prefix, section->segname, section->sectname);

  bfdsec = bfd_make_section_anyway (abfd, sname);
  if (bfdsec == NULL) { return NULL; }
  
  bfdsec->vma = section->addr;
  bfdsec->lma = section->addr;
  bfdsec->_raw_size = section->size;
  bfdsec->filepos = section->offset;
  bfdsec->alignment_power = section->align;

  if (section->flags & BFD_MACH_O_S_ZEROFILL) {
    bfdsec->flags = SEC_ALLOC;
  } else {
    bfdsec->flags = SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_CODE;
  }

  return bfdsec;
}

static int
bfd_mach_o_scan_read_section (abfd, section, offset)
     bfd *abfd;
     bfd_mach_o_section *section;
     bfd_vma offset;
{
  unsigned char buf[68];

  bfd_seek (abfd, offset, SEEK_SET);
  if (bfd_bread ((PTR) buf, 68, abfd) != 68) { return -1; }
  
  memcpy (section->sectname, buf, 16);
  section->sectname[16] = '\0';
  memcpy (section->segname, buf + 16, 16);
  section->segname[16] = '\0';
  section->addr = bfd_h_get_32 (abfd, buf + 32);
  section->size = bfd_h_get_32 (abfd, buf + 36);
  section->offset = bfd_h_get_32 (abfd, buf + 40);
  section->align = bfd_h_get_32 (abfd, buf + 44);
  section->reloff = bfd_h_get_32 (abfd, buf + 48);
  section->nreloc = bfd_h_get_32 (abfd, buf + 52);
  section->flags = bfd_h_get_32 (abfd, buf + 56);
  section->reserved1 = bfd_h_get_32 (abfd, buf + 60);
  section->reserved2 = bfd_h_get_32 (abfd, buf + 64);

  section->bfdsection = bfd_mach_o_make_bfd_section (abfd, section);
  if (section->bfdsection == NULL) { return -1; }

  return 0;
}

static int
bfd_mach_o_scan_write_section (abfd, section, offset)
     bfd *abfd;
     bfd_mach_o_section *section;
     bfd_vma offset;
{
  unsigned char buf[68];

  memcpy (buf, section->sectname, 16);
  memcpy (buf + 16, section->segname, 16);
  bfd_h_put_32 (abfd, section->addr, buf + 32);
  bfd_h_put_32 (abfd, section->size, buf + 36);
  bfd_h_put_32 (abfd, section->offset, buf + 40);
  bfd_h_put_32 (abfd, section->align, buf + 44);
  bfd_h_put_32 (abfd, section->reloff, buf + 48);
  bfd_h_put_32 (abfd, section->nreloc, buf + 52);
  bfd_h_put_32 (abfd, section->flags, buf + 56);
  /* bfd_h_put_32 (abfd, section->reserved1, buf + 60); */
  /* bfd_h_put_32 (abfd, section->reserved2, buf + 64); */

  bfd_seek (abfd, offset, SEEK_SET);
  if (bfd_bwrite ((PTR) buf, 68, abfd) != 68) { return -1; }
  
  return 0;
}

static int
bfd_mach_o_scan_write_symtab_symbols (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  bfd_mach_o_symtab_command *sym = &command->command.symtab;
  asymbol *s = NULL;
  unsigned long i;

  for (i = 0; i < sym->nsyms; i++) {

    unsigned char buf[12];
    bfd_vma symoff = sym->symoff + (i * 12);

    unsigned char ntype = 0;
    unsigned char nsect = 0;
    short ndesc = 0;

    s = &sym->symbols[i];

/* don't set this from the symbol information; use stored values */
#if 0 
    if (s->flags & BSF_GLOBAL) { ntype |= N_EXT; }
    if (s->flags & BSF_DEBUGGING) { ntype |= N_STAB; }

    if (s->section == bfd_und_section_ptr) {
      ntype |= N_UNDF;
    } else if (s->section == bfd_abs_section_ptr) {
      ntype |= N_ABS;
    } else {
      ntype |= N_SECT;
    }
#endif
      
    /* instead just set from the stored values */

    ntype = (s->udata.i >> 24) & 0xff;
    nsect = (s->udata.i >> 16) & 0xff;
    ndesc = s->udata.i & 0xffff;
    
    bfd_h_put_32 (abfd, s->name - sym->strtab, buf);
    bfd_h_put_8 (abfd, ntype, buf + 4);
    bfd_h_put_8 (abfd, nsect, buf + 5);
    bfd_h_put_16 (abfd, ndesc, buf + 6);
    bfd_h_put_32 (abfd, s->section->vma + s->value, buf + 8);

    bfd_seek (abfd, symoff, SEEK_SET);
    if (bfd_bwrite ((PTR) buf, 12, abfd) != 12) { 
      fprintf (stderr, "bfd_mach_o_scan_write_symtab_symbols: unable to write %d bytes at %lu\n", 
	       12, (unsigned long) symoff);
      return -1; 
    }
  }

  return 0;
}

int bfd_mach_o_scan_read_symtab_symbol (abfd, sym, s, i)
     bfd *abfd;
     bfd_mach_o_symtab_command *sym;
     asymbol *s;
     unsigned long i;
{
  bfd_mach_o_data_struct *mdata = abfd->tdata.mach_o_data;
  bfd_vma symoff = sym->symoff + (i * 12);

  unsigned char buf[12];
  unsigned char type = -1;
  unsigned char section = -1;
  short desc = -1;
  long value = -1;
  unsigned long stroff = -1;
  unsigned int symtype = -1;

  BFD_ASSERT (sym->strtab != NULL);

  bfd_seek (abfd, symoff, SEEK_SET);
  if (bfd_bread ((PTR) buf, 12, abfd) != 12) { 
    fprintf (stderr, "bfd_mach_o_scan_read_symtab_symbol: unable to read %d bytes at %lu\n",
	     12, (unsigned long) symoff);
    return -1; 
  }
    
  stroff = bfd_h_get_32 (abfd, buf);
  type = bfd_h_get_8 (abfd, buf + 4);
  symtype = (type & 0x0e);
  section = bfd_h_get_8 (abfd, buf + 5) - 1;
  desc = bfd_h_get_16 (abfd, buf + 6);
  value = bfd_h_get_32 (abfd, buf + 8);

  if (stroff >= sym->strsize) { 
    fprintf (stderr, "bfd_mach_o_scan_read_symtab_symbol: symbol name out of range (%lu >= %lu)\n",
	     (unsigned long) stroff, (unsigned long) sym->strsize);
    return -1; 
  }   

  s->the_bfd = abfd;
  s->name = sym->strtab + stroff;
  s->value = value;

  s->udata.i = (type << 24) | (section << 16) | desc;

  s->flags = 0x0;

  if (type & BFD_MACH_O_N_STAB) {

    s->flags |= BSF_DEBUGGING;
    s->section = bfd_und_section_ptr;

  } else {

    if (type & BFD_MACH_O_N_PEXT) {
      type &= ~BFD_MACH_O_N_PEXT;
      s->flags |= BSF_GLOBAL;
    }

    if (type & BFD_MACH_O_N_EXT) {
      type &= ~BFD_MACH_O_N_EXT;
      s->flags |= BSF_GLOBAL;
    }

    switch (symtype) {
    case BFD_MACH_O_N_UNDF:
      s->section = bfd_und_section_ptr;
      break;
    case BFD_MACH_O_N_PBUD:
      s->section = bfd_und_section_ptr;
      break;
    case BFD_MACH_O_N_ABS:
      s->section = bfd_abs_section_ptr;
      break;
    case BFD_MACH_O_N_SECT:
      if ((section > 0) && (section <= mdata->nsects)) { 
	s->section = mdata->sections[section - 1]->bfdsection;
	s->value = s->value - mdata->sections[section - 1]->addr;
      } else {
	/* Mach-O uses 0 to mean "no section"; not an error */
	if (section != 0) {
	  fprintf (stderr, "bfd_mach_o_scan_read_symtab_symbol: "
		   "symbol \"%s\" specified invalid section %d (max %lu): setting to undefined\n", 
		   s->name, section, mdata->nsects);
	}
	s->section = bfd_und_section_ptr;
      }
      break;
    case BFD_MACH_O_N_INDR:
      fprintf (stderr, "bfd_mach_o_scan_read_symtab_symbol: "
	       "symbol \"%s\" is unsupported 'indirect' reference: setting to undefined\n", 
	       s->name);
      s->section = bfd_und_section_ptr;
      break;
    default:
      fprintf (stderr, "bfd_mach_o_scan_read_symtab_symbol: "
	       "symbol \"%s\" specified invalid type field 0x%x: setting to undefined\n", 
	       s->name, symtype);
      s->section = bfd_und_section_ptr;
      break;
    }
  }

  return 0;
}

int
bfd_mach_o_scan_read_symtab_strtab (abfd, sym)
     bfd *abfd;
     bfd_mach_o_symtab_command *sym;
{
  BFD_ASSERT (sym->strtab == NULL);

  if (abfd->flags & BFD_IN_MEMORY) {
    struct bfd_in_memory *b;
    b = (struct bfd_in_memory *) abfd->iostream;

    if ((sym->stroff + sym->strsize) > b->size) {
      bfd_set_error (bfd_error_file_truncated);
      return -1;
    }
    sym->strtab = b->buffer + sym->stroff;
    return 0;
  }    

  sym->strtab = bfd_alloc (abfd, sym->strsize);
  if (sym->strtab == NULL) { return -1; }

  bfd_seek (abfd, sym->stroff, SEEK_SET);
  if (bfd_bread ((PTR) sym->strtab, sym->strsize, abfd) != sym->strsize) { 
    fprintf (stderr, "bfd_mach_o_scan_read_symtab_strtab: unable to read %lu bytes at %lu\n",
	     sym->strsize, sym->stroff);
    return -1; 
  }

  return 0;
}

int 
bfd_mach_o_scan_read_symtab_symbols (abfd, sym)
     bfd *abfd;
     bfd_mach_o_symtab_command *sym;
{
  unsigned long i;
  int ret;

  BFD_ASSERT (sym->symbols == NULL);
  sym->symbols = bfd_alloc (abfd, sym->nsyms * sizeof (asymbol));
  if (sym->symbols == NULL) {
    fprintf (stderr, "bfd_mach_o_scan_read_symtab_symbols: unable to allocate memory for symbols\n");
    return -1; 
  }
  
  ret = bfd_mach_o_scan_read_symtab_strtab (abfd, sym);
  if (ret != 0) { return ret; }

  for (i = 0; i < sym->nsyms; i++) {
    ret = bfd_mach_o_scan_read_symtab_symbol (abfd, sym, &sym->symbols[i], i);
    if (ret != 0) { return ret; }
  }
  
  return 0;
}

int bfd_mach_o_scan_read_dysymtab_symbol (abfd, dysym, sym, s, i)
     bfd *abfd;
     bfd_mach_o_dysymtab_command *dysym;
     bfd_mach_o_symtab_command *sym;
     asymbol *s;
     unsigned long i;
{
  unsigned long isymoff = dysym->indirectsymoff + (i * 4);
  unsigned long symindex;
  unsigned char buf[4];

  BFD_ASSERT (i < dysym->nindirectsyms);
  
  bfd_seek (abfd, isymoff, SEEK_SET);
  if (bfd_bread ((PTR) buf, 4, abfd) != 4) { 
    fprintf (stderr, "bfd_mach_o_scan_read_dysymtab_symbol: unable to read %lu bytes at %lu\n",
	     (unsigned long) 4, isymoff);
    return -1; 
  }
  symindex = bfd_h_get_32 (abfd, buf);
  
  return bfd_mach_o_scan_read_symtab_symbol (abfd, sym, s, symindex);
}

static const char *bfd_mach_o_i386_flavour_string (flavour)
     unsigned int flavour;
{
  switch (flavour) {
  case BFD_MACH_O_i386_NEW_THREAD_STATE: return "i386_NEW_THREAD_STATE";
  case BFD_MACH_O_i386_FLOAT_STATE: return "i386_FLOAT_STATE";
  case BFD_MACH_O_i386_ISA_PORT_MAP_STATE: return "i386_ISA_PORT_MAP_STATE";
  case BFD_MACH_O_i386_V86_ASSIST_STATE: return "i386_V86_ASSIST_STATE";
  case BFD_MACH_O_i386_REGS_SEGS_STATE: return "i386_REGS_SEGS_STATE";
  case BFD_MACH_O_i386_THREAD_SYSCALL_STATE: return "i386_THREAD_SYSCALL_STATE";
  case BFD_MACH_O_i386_THREAD_STATE_NONE: return "i386_THREAD_STATE_NONE";
  case BFD_MACH_O_i386_SAVED_STATE: return "i386_SAVED_STATE";
  case BFD_MACH_O_i386_THREAD_STATE: return "i386_THREAD_STATE";
  case BFD_MACH_O_i386_THREAD_FPSTATE: return "i386_THREAD_FPSTATE";
  case BFD_MACH_O_i386_THREAD_EXCEPTSTATE: return "i386_THREAD_EXCEPTSTATE";
  case BFD_MACH_O_i386_THREAD_CTHREADSTATE: return "i386_THREAD_CTHREADSTATE";
  default: return "UNKNOWN";
  }
}

static const char *bfd_mach_o_ppc_flavour_string (flavour)
     unsigned int flavour;
{
  switch (flavour) {
  case BFD_MACH_O_PPC_THREAD_STATE: return "PPC_THREAD_STATE";
  case BFD_MACH_O_PPC_FLOAT_STATE: return "PPC_FLOAT_STATE";
  case BFD_MACH_O_PPC_EXCEPTION_STATE: return "PPC_EXCEPTION_STATE";
  case BFD_MACH_O_PPC_VECTOR_STATE: return "PPC_VECTOR_STATE";
  default: return "UNKNOWN";
  }
}

static int
bfd_mach_o_scan_write_thread (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  bfd_mach_o_thread_command *cmd = &command->command.thread;
  unsigned int i;
  unsigned char buf[8];
  bfd_vma offset;
  unsigned int nflavours;

  BFD_ASSERT ((command->type == BFD_MACH_O_LC_THREAD)
	      || (command->type == BFD_MACH_O_LC_UNIXTHREAD));

  offset = 8;
  nflavours = 0;
  for (i = 0; i < cmd->nflavours; i++) {

    BFD_ASSERT ((cmd->flavours[i].size % 4) == 0);
    BFD_ASSERT (cmd->flavours[i].offset == (command->offset + offset + 8));

    bfd_h_put_32 (abfd, cmd->flavours[i].flavour, buf);
    bfd_h_put_32 (abfd, (cmd->flavours[i].size / 4), buf + 4);

    bfd_seek (abfd, command->offset + offset, SEEK_SET);
    if (bfd_bwrite ((PTR) buf, 8, abfd) != 8) { return -1; }

    offset += cmd->flavours[i].size + 8;
  }

  return 0;
}

static int
bfd_mach_o_scan_read_dylinker (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  bfd_mach_o_dylinker_command *cmd = &command->command.dylinker;
  unsigned char buf[4];
  unsigned int nameoff;

  BFD_ASSERT ((command->type == BFD_MACH_O_LC_ID_DYLINKER)
	      || (command->type == BFD_MACH_O_LC_LOAD_DYLINKER));

  bfd_seek (abfd, command->offset + 8, SEEK_SET);
  if (bfd_bread ((PTR) buf, 4, abfd) != 4) { return -1; }

  nameoff = bfd_h_get_32 (abfd, buf + 0);

  cmd->name_offset = command->offset + nameoff;
  cmd->name_len = command->len - nameoff;

  {
    asection *bfdsec;
    char *sname;

    const char *prefix;
    if (command->type == BFD_MACH_O_LC_LOAD_DYLINKER) {
      prefix = "LC_LOAD_DYLINKER";
    } else if (command->type == BFD_MACH_O_LC_ID_DYLINKER) {
      prefix = "LC_ID_DYLINKER";
    } else {
      abort ();
    }

    sname = (char *) bfd_alloc (abfd, strlen (prefix) + 1);
    if (sname == NULL) { return -1; }
    strcpy (sname, prefix);

    bfdsec = bfd_make_section_anyway (abfd, sname);
    if (bfdsec == NULL) { return -1; }
  
    bfdsec->vma = 0;
    bfdsec->lma = 0;
    bfdsec->_raw_size = command->len - 8;
    bfdsec->filepos = command->offset + 8;
    bfdsec->alignment_power = 0;
    bfdsec->flags = SEC_HAS_CONTENTS;

    cmd->section = bfdsec;
  }

  return 0;
}

static int
bfd_mach_o_scan_read_dylib (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  bfd_mach_o_dylib_command *cmd = &command->command.dylib;
  unsigned char buf[16];
  unsigned int nameoff;

  BFD_ASSERT ((command->type == BFD_MACH_O_LC_ID_DYLIB)
	      || (command->type == BFD_MACH_O_LC_LOAD_DYLIB));

  bfd_seek (abfd, command->offset + 8, SEEK_SET);
  if (bfd_bread ((PTR) buf, 16, abfd) != 16) { return -1; }

  nameoff = bfd_h_get_32 (abfd, buf + 0);
  cmd->timestamp = bfd_h_get_32 (abfd, buf + 4);
  cmd->current_version = bfd_h_get_32 (abfd, buf + 8);
  cmd->compatibility_version = bfd_h_get_32 (abfd, buf + 12);

  cmd->name_offset = command->offset + nameoff;
  cmd->name_len = command->len - nameoff;

  {
    asection *bfdsec;
    char *sname;

    const char *prefix;
    if (command->type == BFD_MACH_O_LC_LOAD_DYLIB) {
      prefix = "LC_LOAD_DYLIB";
    } else if (command->type == BFD_MACH_O_LC_ID_DYLIB) {
      prefix = "LC_ID_DYLIB";
    } else {
      abort ();
    }

    sname = (char *) bfd_alloc (abfd, strlen (prefix) + 1);
    if (sname == NULL) { return -1; }
    strcpy (sname, prefix);

    bfdsec = bfd_make_section_anyway (abfd, sname);
    if (bfdsec == NULL) { return -1; }
  
    bfdsec->vma = 0;
    bfdsec->lma = 0;
    bfdsec->_raw_size = command->len - 8;
    bfdsec->filepos = command->offset + 8;
    bfdsec->alignment_power = 0;
    bfdsec->flags = SEC_HAS_CONTENTS;

    cmd->section = bfdsec;
  }

  return 0;
}

static int
bfd_mach_o_scan_read_prebound_dylib (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  /* bfd_mach_o_prebound_dylib_command *cmd = &command->command.prebound_dylib; */

  BFD_ASSERT (command->type == BFD_MACH_O_LC_PREBOUND_DYLIB);
  return 0;
}

static int
bfd_mach_o_scan_read_thread (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  bfd_mach_o_data_struct *mdata = NULL;
  bfd_mach_o_thread_command *cmd = &command->command.thread;
  unsigned char buf[8];
  bfd_vma offset;
  unsigned int nflavours;
  unsigned int i;

  BFD_ASSERT ((command->type == BFD_MACH_O_LC_THREAD)
	      || (command->type == BFD_MACH_O_LC_UNIXTHREAD));

  BFD_ASSERT (bfd_mach_o_valid (abfd));
  mdata = abfd->tdata.mach_o_data;
  
  offset = 8;
  nflavours = 0;
  while (offset != command->len) {
    if (offset >= command->len) { return -1; }
    bfd_seek (abfd, command->offset + offset, SEEK_SET);
    if (bfd_bread ((PTR) buf, 8, abfd) != 8) { return -1; }
    offset += 8 + bfd_h_get_32 (abfd, buf + 4) * 4;
    nflavours++;
  }

  cmd->flavours =
    ((bfd_mach_o_thread_flavour *)
     bfd_alloc (abfd, nflavours * sizeof (bfd_mach_o_thread_flavour)));
  if (cmd->flavours == NULL) { return -1; }
  cmd->nflavours = nflavours;
  
  offset = 8;
  nflavours = 0;
  while (offset != command->len) {
    if (offset >= command->len) { return -1; }
    if (nflavours >= cmd->nflavours) { return -1; }
    bfd_seek (abfd, command->offset + offset, SEEK_SET);
    if (bfd_bread ((PTR) buf, 8, abfd) != 8) { return -1; }
    cmd->flavours[nflavours].flavour = bfd_h_get_32 (abfd, buf);
    cmd->flavours[nflavours].offset = command->offset + offset + 8;
    cmd->flavours[nflavours].size = bfd_h_get_32 (abfd, buf + 4) * 4;
    offset += cmd->flavours[nflavours].size + 8;
    nflavours++;
  }

  for (i = 0; i < nflavours; i++) {

    asection *bfdsec;
    unsigned int snamelen;
    char *sname;
    const char *flavourstr;
    
    const char *prefix = "LC_THREAD";
    
    switch (mdata->header.cputype) {
    case BFD_MACH_O_CPU_TYPE_POWERPC:
      flavourstr = bfd_mach_o_ppc_flavour_string (cmd->flavours[i].flavour);
      break;
    case BFD_MACH_O_CPU_TYPE_I386:
      flavourstr = bfd_mach_o_i386_flavour_string (cmd->flavours[i].flavour);
      break;
    default:
      flavourstr = "UNKNOWN_ARCHITECTURE";
      break;
    }
    
    snamelen = strlen (prefix) + 1 + 20 + 1 + strlen (flavourstr) + 1;
    sname = (char *) bfd_alloc (abfd, snamelen);
    if (sname == NULL) { return -1; }
    sprintf (sname, "%s.%s.%u", prefix, flavourstr, 0);

    bfdsec = bfd_make_section_anyway (abfd, sname);
    if (bfdsec == NULL) { return -1; }
  
    bfdsec->vma = 0;
    bfdsec->lma = 0;
    bfdsec->_raw_size = cmd->flavours[i].size;
    bfdsec->filepos = cmd->flavours[i].offset;
    bfdsec->alignment_power = 0x0;
    bfdsec->flags = SEC_HAS_CONTENTS;

    cmd->section = bfdsec;
  }

  return 0;
}

static int 
bfd_mach_o_scan_write_symtab (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  bfd_mach_o_symtab_command *seg = &command->command.symtab;
  unsigned char buf[16];

  BFD_ASSERT (command->type == BFD_MACH_O_LC_SYMTAB);

  bfd_h_put_32 (abfd, seg->symoff, buf);
  bfd_h_put_32 (abfd, seg->nsyms, buf + 4);
  bfd_h_put_32 (abfd, seg->stroff, buf + 8);
  bfd_h_put_32 (abfd, seg->strsize, buf + 12);

  bfd_seek (abfd, command->offset + 8, SEEK_SET);
  if (bfd_bwrite ((PTR) buf, 16, abfd) != 16) { return -1; }
  
  if (bfd_mach_o_scan_write_symtab_symbols (abfd, command) != 0) { return -1; }

  return 0;
}

static int 
bfd_mach_o_scan_read_dysymtab (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  bfd_mach_o_dysymtab_command *seg = &command->command.dysymtab;
  unsigned char buf[72];

  BFD_ASSERT (command->type == BFD_MACH_O_LC_DYSYMTAB);

  bfd_seek (abfd, command->offset + 8, SEEK_SET);
  if (bfd_bread ((PTR) buf, 72, abfd) != 72) { return -1; }
  
  seg->ilocalsym = bfd_h_get_32 (abfd, buf + 0);
  seg->nlocalsym = bfd_h_get_32 (abfd, buf + 4);
  seg->iextdefsym = bfd_h_get_32 (abfd, buf + 8);
  seg->nextdefsym = bfd_h_get_32 (abfd, buf + 12);
  seg->iundefsym = bfd_h_get_32 (abfd, buf + 16);
  seg->nundefsym = bfd_h_get_32 (abfd, buf + 20);
  seg->tocoff = bfd_h_get_32 (abfd, buf + 24);
  seg->ntoc = bfd_h_get_32 (abfd, buf + 28);
  seg->modtaboff = bfd_h_get_32 (abfd, buf + 32);
  seg->nmodtab = bfd_h_get_32 (abfd, buf + 36);
  seg->extrefsymoff = bfd_h_get_32 (abfd, buf + 40);
  seg->nextrefsyms = bfd_h_get_32 (abfd, buf + 44);
  seg->indirectsymoff = bfd_h_get_32 (abfd, buf + 48);
  seg->nindirectsyms = bfd_h_get_32 (abfd, buf + 52);
  seg->extreloff = bfd_h_get_32 (abfd, buf + 56);
  seg->nextrel = bfd_h_get_32 (abfd, buf + 60);
  seg->locreloff = bfd_h_get_32 (abfd, buf + 64);
  seg->nlocrel = bfd_h_get_32 (abfd, buf + 68);

  return 0;
}

static int 
bfd_mach_o_scan_read_symtab (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  bfd_mach_o_symtab_command *seg = &command->command.symtab;
  unsigned char buf[16];

  BFD_ASSERT (command->type == BFD_MACH_O_LC_SYMTAB);

  bfd_seek (abfd, command->offset + 8, SEEK_SET);
  if (bfd_bread ((PTR) buf, 16, abfd) != 16) { return -1; }
  
  seg->symoff = bfd_h_get_32 (abfd, buf);
  seg->nsyms = bfd_h_get_32 (abfd, buf + 4);
  seg->stroff = bfd_h_get_32 (abfd, buf + 8);
  seg->strsize = bfd_h_get_32 (abfd, buf + 12);

  seg->symbols = NULL;
  seg->strtab = NULL;

  {
    asection *bfdsec;
    char *sname;

    const char *prefix = "LC_SYMTAB.stabs";
    sname = (char *) bfd_alloc (abfd, strlen (prefix) + 1);
    if (sname == NULL) { return -1; }
    strcpy (sname, prefix);

    bfdsec = bfd_make_section_anyway (abfd, sname);
    if (bfdsec == NULL) { return -1; }
  
    bfdsec->vma = 0;
    bfdsec->lma = 0;
    bfdsec->_raw_size = seg->nsyms * 12;
    bfdsec->filepos = seg->symoff;
    bfdsec->alignment_power = 0;
    bfdsec->flags = SEC_HAS_CONTENTS;

    seg->stabs_segment = bfdsec;
  }

  {
    asection *bfdsec;
    char *sname;

    const char *prefix = "LC_SYMTAB.stabstr";
    sname = (char *) bfd_alloc (abfd, strlen (prefix) + 1);
    if (sname == NULL) { return -1; }
    strcpy (sname, prefix);

    bfdsec = bfd_make_section_anyway (abfd, sname);
    if (bfdsec == NULL) { return -1; }
  
    bfdsec->vma = 0;
    bfdsec->lma = 0;
    bfdsec->_raw_size = seg->strsize;
    bfdsec->filepos = seg->stroff;
    bfdsec->alignment_power = 0;
    bfdsec->flags = SEC_HAS_CONTENTS;

    seg->stabstr_segment = bfdsec;  }

  return 0;
}

static int
bfd_mach_o_scan_read_segment (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  unsigned char buf[48];
  bfd_mach_o_segment_command *seg = &command->command.segment;
  unsigned long i;
  
  BFD_ASSERT (command->type == BFD_MACH_O_LC_SEGMENT);

  bfd_seek (abfd, command->offset + 8, SEEK_SET);
  if (bfd_bread ((PTR) buf, 48, abfd) != 48) { return -1; }

  memcpy (seg->segname, buf, 16);
  seg->vmaddr = bfd_h_get_32 (abfd, buf + 16);
  seg->vmsize = bfd_h_get_32 (abfd, buf + 20);
  seg->fileoff = bfd_h_get_32 (abfd, buf + 24);
  seg->filesize = bfd_h_get_32 (abfd, buf +  28);
  /* seg->maxprot = bfd_h_get_32 (abfd, buf + 32); */
  /* seg->initprot = bfd_h_get_32 (abfd, buf + 36); */
  seg->nsects = bfd_h_get_32 (abfd, buf + 40);
  seg->flags = bfd_h_get_32 (abfd, buf + 44);

  { 
    asection *bfdsec;
    char *sname;

    const char *prefix = "LC_SEGMENT";
    unsigned int snamelen = strlen (prefix) + 1 + strlen (seg->segname) + 1;

    sname = (char *) bfd_alloc (abfd, snamelen);
    if (sname == NULL) { return -1; }
    sprintf (sname, "%s.%s", prefix, seg->segname);

    bfdsec = bfd_make_section_anyway (abfd, sname);
    if (bfdsec == NULL) { return -1; }
  
    bfdsec->vma = seg->vmaddr;
    bfdsec->lma = seg->vmaddr;
    bfdsec->_raw_size = seg->filesize;
    bfdsec->filepos = seg->fileoff;
    bfdsec->alignment_power = 0x0;
    bfdsec->flags = SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_CODE;

    seg->segment = bfdsec;
  }

  if (seg->nsects != 0) {
    
    seg->sections = 
      ((bfd_mach_o_section *)
       bfd_alloc (abfd, seg->nsects * sizeof (bfd_mach_o_section)));
    if (seg->sections == NULL) { return -1; }
    
    for (i = 0; i < seg->nsects; i++) {
      bfd_vma segoff = command->offset + 48 + 8 + (i * 68);
      if (bfd_mach_o_scan_read_section (abfd, &seg->sections[i], segoff) != 0) { 
	return -1;
      }
    }    
  }

  return 0;
}

static int
bfd_mach_o_scan_write_segment (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  unsigned char buf[48];
  bfd_mach_o_segment_command *seg = &command->command.segment;
  bfd_mach_o_data_struct *mdata = abfd->tdata.mach_o_data;
  unsigned long i;
  
  BFD_ASSERT (command->type == BFD_MACH_O_LC_SEGMENT);

  memcpy (buf, seg->segname, 16);
  bfd_h_put_32 (abfd, seg->vmaddr, buf + 16);
  bfd_h_put_32 (abfd, seg->vmsize, buf + 20);
  bfd_h_put_32 (abfd, seg->fileoff, buf + 24);
  bfd_h_put_32 (abfd, seg->filesize, buf + 28);
  bfd_h_put_32 (abfd, 0 /* seg->maxprot */, buf + 32);
  bfd_h_put_32 (abfd, 0 /* seg->initprot */, buf + 36);
  bfd_h_put_32 (abfd, seg->nsects, buf + 40);
  bfd_h_put_32 (abfd, seg->flags, buf + 44);

  bfd_seek (abfd, command->offset + 8, SEEK_SET);
  if (bfd_bwrite ((PTR) buf, 48, abfd) != 48) { return -1; }

  if (mdata->ibfd == NULL) { return false; }
  {
    char buf[1024];
    bfd *ibfd = mdata->ibfd;
    bfd_vma nbytes = seg->filesize;
    bfd_vma curoff = seg->fileoff;
    
    while (nbytes > 0) {

      bfd_vma thisread = nbytes;
      if (thisread > 1024) { thisread = 1024; }

      bfd_seek (ibfd, curoff, SEEK_SET);
      if (bfd_bread ((PTR) buf, thisread, ibfd) != thisread) { return -1; }

      bfd_seek (abfd, curoff, SEEK_SET);
      if (bfd_bwrite ((PTR) buf, thisread, abfd) != thisread) { return -1; }

      nbytes -= thisread;
      curoff += thisread;
    }
  }

  for (i = 0; i < seg->nsects; i++) {
    bfd_vma segoff = command->offset + 48 + 8 + (i * 68);
    if (bfd_mach_o_scan_write_section (abfd, &seg->sections[i], segoff) != 0) { 
      return -1;
    }
  }

  return 0;
}

static int
bfd_mach_o_scan_read_command (abfd, command)
     bfd *abfd;
     bfd_mach_o_load_command *command;
{
  unsigned char buf[8];

  bfd_seek (abfd, command->offset, SEEK_SET);
  if (bfd_bread ((PTR) buf, 8, abfd) != 8) { return -1; }

  command->type = bfd_h_get_32 (abfd, buf);
  command->len = bfd_h_get_32 (abfd, buf + 4);

  switch (command->type) {
  case BFD_MACH_O_LC_SEGMENT:
    if (bfd_mach_o_scan_read_segment (abfd, command) != 0) { return -1; }
    break;
  case BFD_MACH_O_LC_SYMTAB:
    if (bfd_mach_o_scan_read_symtab (abfd, command) != 0) { return -1; }
    break;
  case BFD_MACH_O_LC_SYMSEG:
    break;
  case BFD_MACH_O_LC_THREAD:
  case BFD_MACH_O_LC_UNIXTHREAD:
    if (bfd_mach_o_scan_read_thread (abfd, command) != 0) { return -1; }
    break;
  case BFD_MACH_O_LC_LOAD_DYLINKER:
  case BFD_MACH_O_LC_ID_DYLINKER:
    if (bfd_mach_o_scan_read_dylinker (abfd, command) != 0) { return -1; }
    break;
  case BFD_MACH_O_LC_LOAD_DYLIB:
  case BFD_MACH_O_LC_ID_DYLIB:
  case BFD_MACH_O_LC_LOAD_WEAK_DYLIB:
    if (bfd_mach_o_scan_read_dylib (abfd, command) != 0) { return -1; }
    break;
  case BFD_MACH_O_LC_PREBOUND_DYLIB:
    if (bfd_mach_o_scan_read_prebound_dylib (abfd, command) != 0) { return -1; }
    break;
  case BFD_MACH_O_LC_LOADFVMLIB:
  case BFD_MACH_O_LC_IDFVMLIB:
  case BFD_MACH_O_LC_IDENT:
  case BFD_MACH_O_LC_FVMFILE:
  case BFD_MACH_O_LC_PREPAGE:
  case BFD_MACH_O_LC_ROUTINES:
  case BFD_MACH_O_LC_SUB_FRAMEWORK:
    break;
  case BFD_MACH_O_LC_DYSYMTAB:
    if (bfd_mach_o_scan_read_dysymtab (abfd, command) != 0) { return -1; }
    break;
  case BFD_MACH_O_LC_SUB_UMBRELLA:
  case BFD_MACH_O_LC_SUB_CLIENT:
  case BFD_MACH_O_LC_SUB_LIBRARY:
  case BFD_MACH_O_LC_TWOLEVEL_HINTS:
  case BFD_MACH_O_LC_PREBIND_CKSUM:
    break;
  default:
    fprintf (stderr, "unable to read unknown load command 0x%lx\n",
	     (unsigned long) command->type);
    break;
  }

  return 0;
}

static void
bfd_mach_o_flatten_sections (abfd)
     bfd *abfd;
{
  bfd_mach_o_data_struct *mdata = abfd->tdata.mach_o_data;
  long csect = 0;
  unsigned long i, j;
  
  mdata->nsects = 0;

  for (i = 0; i < mdata->header.ncmds; i++) {
    if (mdata->commands[i].type == BFD_MACH_O_LC_SEGMENT) {
      bfd_mach_o_segment_command *seg = &mdata->commands[i].command.segment;
      mdata->nsects += seg->nsects;
    }
  }

  mdata->sections = bfd_alloc (abfd, mdata->nsects * sizeof (bfd_mach_o_section *));

  csect = 0;
  for (i = 0; i < mdata->header.ncmds; i++) {
    if (mdata->commands[i].type == BFD_MACH_O_LC_SEGMENT) {
      bfd_mach_o_segment_command *seg = &mdata->commands[i].command.segment;
      BFD_ASSERT (csect + seg->nsects <= mdata->nsects);
      for (j = 0; j < seg->nsects; j++) {
	mdata->sections[csect++] = &seg->sections[j];
      }
    }
  }
}

int
bfd_mach_o_scan_start_address (abfd)
     bfd *abfd;
{
  bfd_mach_o_data_struct *mdata = abfd->tdata.mach_o_data;
  bfd_mach_o_thread_command *cmd = NULL;
  unsigned long i;

  for (i = 0; i < mdata->header.ncmds; i++) {
    if ((mdata->commands[i].type == BFD_MACH_O_LC_THREAD) ||
	(mdata->commands[i].type == BFD_MACH_O_LC_UNIXTHREAD)) {
      if (cmd == NULL) {
	cmd = &mdata->commands[i].command.thread;
      } else {
	return 0;
      }
    }
  }
  if (cmd == NULL) { return 0; }

  for (i = 0; i < cmd->nflavours; i++) {
    if ((mdata->header.cputype == BFD_MACH_O_CPU_TYPE_I386) 
	&& (cmd->flavours[i].flavour == BFD_MACH_O_i386_THREAD_STATE)) {
      unsigned char buf[4];
      bfd_seek (abfd, cmd->flavours[i].offset + 40, SEEK_SET);
      if (bfd_bread (buf, 4, abfd) != 4) { return -1; }
      abfd->start_address = bfd_h_get_32 (abfd, buf);
    } else if ((mdata->header.cputype == BFD_MACH_O_CPU_TYPE_POWERPC) 
	       && (cmd->flavours[i].flavour == BFD_MACH_O_PPC_THREAD_STATE)) {
      unsigned char buf[4];
      bfd_seek (abfd, cmd->flavours[i].offset + 0, SEEK_SET);
      if (bfd_bread (buf, 4, abfd) != 4) { return -1; }
      abfd->start_address = bfd_h_get_32 (abfd, buf);
    }     
  }

  return 0;
}

int
bfd_mach_o_scan (abfd, header)
     bfd *abfd;
     bfd_mach_o_header *header;
{
  unsigned int i;

  bfd_mach_o_data_struct *mdata = NULL;
  enum bfd_architecture cputype;
  unsigned long cpusubtype;

  mdata = ((bfd_mach_o_data_struct *) 
	   bfd_alloc (abfd, sizeof (bfd_mach_o_data_struct)));
  if (mdata == NULL) { return -1; }
  
  mdata->header = *header;
  mdata->symbols = NULL;

  abfd->flags = abfd->xvec->object_flags | (abfd->flags & (BFD_IN_MEMORY | BFD_IO_FUNCS));
  
  abfd->tdata.mach_o_data = mdata;

  bfd_mach_o_convert_architecture (header->cputype, header->cpusubtype, &cputype, &cpusubtype);
  if (cputype == bfd_arch_unknown) {
    fprintf (stderr, "bfd_mach_o_scan: unknown architecture 0x%lx/0x%lx\n", header->cputype, header->cpusubtype);
    return -1;
  }
  bfd_set_arch_mach (abfd, cputype, cpusubtype);
  
  if (header->ncmds != 0) {

    mdata->commands = 
      ((bfd_mach_o_load_command *)
       bfd_alloc (abfd, header->ncmds * sizeof (bfd_mach_o_load_command)));
    if (mdata->commands == NULL) { return -1; }
    
    for (i = 0; i < header->ncmds; i++) {
      bfd_mach_o_load_command *cur = &mdata->commands[i];
      if (i == 0) { 
	cur->offset = 28;
      } else {
	bfd_mach_o_load_command *prev = &mdata->commands[i - 1];
	cur->offset = prev->offset + prev->len;
      }
      if (bfd_mach_o_scan_read_command (abfd, cur) < 0) {
	return -1;
      }
    } 
  }

  if (bfd_mach_o_scan_start_address (abfd) < 0) { 
#if 0
    fprintf (stderr, "bfd_mach_o_scan: unable to scan start address: %s\n",
	     bfd_errmsg (bfd_get_error ()));
    abfd->tdata.mach_o_data = NULL;
    return -1; 
#endif
  }

  bfd_mach_o_flatten_sections (abfd);

  return 0;
}

boolean bfd_mach_o_mkobject (abfd)
     bfd *abfd;
{
  bfd_mach_o_data_struct *mdata = NULL;

  mdata = ((bfd_mach_o_data_struct *) 
	   bfd_alloc (abfd, sizeof (bfd_mach_o_data_struct)));
  if (mdata == NULL) { return false; }
  abfd->tdata.mach_o_data = mdata;

  mdata->header.magic = 0;
  mdata->header.cputype = 0;
  mdata->header.cpusubtype = 0;
  mdata->header.filetype = 0;
  mdata->header.ncmds = 0;
  mdata->header.sizeofcmds = 0;
  mdata->header.flags = 0;
  mdata->header.byteorder = BFD_ENDIAN_UNKNOWN;

  mdata->commands = NULL;
  mdata->nsymbols = 0;
  mdata->symbols = NULL;
  mdata->nsects = 0;
  mdata->sections = NULL;

  mdata->ibfd = NULL;

  return true;
}

const bfd_target *
bfd_mach_o_object_p (abfd)
     bfd *abfd;
{
  bfd_mach_o_header header;

  abfd->tdata.mach_o_data = NULL;

  if (bfd_mach_o_read_header (abfd, &header) != 0) {
    abfd->tdata.mach_o_data = NULL;
    bfd_set_error (bfd_error_wrong_format);
    return NULL;
  }

  if (! ((header.byteorder == BFD_ENDIAN_BIG)
	 || (header.byteorder == BFD_ENDIAN_LITTLE))) {
    fprintf (stderr, "unknown header byte-order value 0x%lx\n", (long) header.byteorder);
    bfd_set_error (bfd_error_wrong_format);
    return NULL;
  }

  if (! (((header.byteorder == BFD_ENDIAN_BIG) 
	  && (abfd->xvec->byteorder == BFD_ENDIAN_BIG)
	  && (abfd->xvec->header_byteorder == BFD_ENDIAN_BIG))
	 ||
	 ((header.byteorder == BFD_ENDIAN_LITTLE) 
	  && (abfd->xvec->byteorder == BFD_ENDIAN_LITTLE) 
	  && (abfd->xvec->header_byteorder == BFD_ENDIAN_LITTLE)))) {

    abfd->tdata.mach_o_data = NULL;
    bfd_set_error (bfd_error_wrong_format);
    return NULL;
  }

  if (bfd_mach_o_scan (abfd, &header) != 0) {
    abfd->tdata.mach_o_data = NULL;
    bfd_set_error (bfd_error_wrong_format);
    return NULL;
  }
  
  return abfd->xvec;
}

const bfd_target *
bfd_mach_o_core_p (abfd)
     bfd *abfd;
{
  bfd_mach_o_header header;

  abfd->tdata.mach_o_data = NULL;
  bfd_set_error (bfd_error_wrong_format);

  if (bfd_mach_o_read_header (abfd, &header) != 0) {
    abfd->tdata.mach_o_data = NULL;
    return NULL;
  }

  if (! ((header.byteorder == BFD_ENDIAN_BIG)
	 || (header.byteorder == BFD_ENDIAN_LITTLE))) {
    fprintf (stderr, "unknown header byte-order value 0x%lx\n", (long) header.byteorder);
    abort ();
  }

  if (! (((header.byteorder == BFD_ENDIAN_BIG) 
	  && (abfd->xvec->byteorder == BFD_ENDIAN_BIG)
	  && (abfd->xvec->header_byteorder == BFD_ENDIAN_BIG))
	 ||
	 ((header.byteorder == BFD_ENDIAN_LITTLE) 
	  && (abfd->xvec->byteorder == BFD_ENDIAN_LITTLE) 
	  && (abfd->xvec->header_byteorder == BFD_ENDIAN_LITTLE)))) {

    abfd->tdata.mach_o_data = NULL;
    return NULL;
  }

  if (header.filetype != BFD_MACH_O_MH_CORE) {
    abfd->tdata.mach_o_data = NULL;
    return NULL;
  }

  if (bfd_mach_o_scan (abfd, &header) != 0) {
    abfd->tdata.mach_o_data = NULL;
    return NULL;
  }
  
  return abfd->xvec;
}

typedef struct mach_o_fat_archentry {
  unsigned long cputype;
  unsigned long cpusubtype;
  unsigned long offset;
  unsigned long size;
  unsigned long align;
  bfd *abfd;
} mach_o_fat_archentry;

typedef struct mach_o_fat_data_struct {
  unsigned long magic;
  unsigned long nfat_arch;
  mach_o_fat_archentry *archentries;
} mach_o_fat_data_struct;

const bfd_target *
bfd_mach_o_archive_p (abfd)
     bfd *abfd;
{
  mach_o_fat_data_struct *adata;
  unsigned char buf[20];
  unsigned long i;

  bfd_seek (abfd, 0, SEEK_SET);
  if (bfd_bread ((PTR) buf, 8, abfd) != 8) { return NULL; }

  adata = (mach_o_fat_data_struct *) 
    bfd_alloc (abfd, sizeof (mach_o_fat_data_struct));
  if (adata == NULL) { return NULL; }
  
  adata->magic = bfd_getb32 (buf);
  adata->nfat_arch = bfd_getb32 (buf + 4);
  if (adata->magic != 0xcafebabe) { return NULL; }

  adata->archentries = (mach_o_fat_archentry *) 
    bfd_alloc (abfd, adata->nfat_arch * sizeof (mach_o_fat_archentry));
  if (adata->archentries == NULL) { return NULL; }

  for (i = 0; i < adata->nfat_arch; i++) { 
    bfd_seek (abfd, 8 + 20 * i, SEEK_SET);
    if (bfd_bread ((PTR) buf, 20, abfd) != 20) { return NULL; }
    adata->archentries[i].cputype = bfd_getb32 (buf);
    adata->archentries[i].cpusubtype = bfd_getb32 (buf + 4);
    adata->archentries[i].offset = bfd_getb32 (buf + 8);
    adata->archentries[i].size = bfd_getb32 (buf + 12);
    adata->archentries[i].align = bfd_getb32 (buf + 16);
    adata->archentries[i].abfd = NULL;
  }

  abfd->tdata.mach_o_fat_data = adata;
  return abfd->xvec;
}

bfd *
bfd_mach_o_openr_next_archived_file (archive, prev)
  bfd *archive;
  bfd *prev;
{
  mach_o_fat_data_struct *adata = (mach_o_fat_data_struct *) archive->tdata.mach_o_fat_data;
  mach_o_fat_archentry *entry = NULL;
  unsigned long i;

  BFD_ASSERT (adata != NULL);

  /* find index of previous entry */
  if (prev == NULL) {
    i = 0;			/* start at first one */
  } else {
    for (i = 0; i < adata->nfat_arch; i++) {
      if (adata->archentries[i].abfd == prev) {
	break;
      }
    }
    if (i == adata->nfat_arch) { /* not found */
      bfd_set_error (bfd_error_bad_value);
      return NULL; 
    }	
    i++;			/* get next entry */
  }
  
  if (i >= adata->nfat_arch) {
    bfd_set_error (bfd_error_no_more_archived_files);
    return NULL;
  }

  entry = &adata->archentries[i];
  if (entry->abfd == NULL) {
    bfd *nbfd = _bfd_new_bfd_contained_in (archive);
    if (nbfd == NULL) { return NULL; }
    nbfd->origin = entry->offset;
    nbfd->filename = bfd_malloc (strlen (archive->filename) + 1);
    if (nbfd->filename == NULL) { return NULL; }
    strcpy (nbfd->filename, archive->filename);
    nbfd->iostream = NULL;
    entry->abfd = nbfd;
  }
  return entry->abfd;
}

int bfd_mach_o_lookup_section 
  (bfd *abfd, asection *section, 
   bfd_mach_o_load_command **mcommand, bfd_mach_o_section **msection)
{
  struct mach_o_data_struct *md = abfd->tdata.mach_o_data;
  unsigned int i, j, num;

  bfd_mach_o_load_command *ncmd = NULL;
  bfd_mach_o_section *nsect = NULL;

  BFD_ASSERT (mcommand != NULL);
  BFD_ASSERT (msection != NULL);

  num = 0;
  for (i = 0; i < md->header.ncmds; i++) {

    struct bfd_mach_o_load_command *cmd = &md->commands[i];
    struct bfd_mach_o_segment_command *seg = NULL;

    if (cmd->type != BFD_MACH_O_LC_SEGMENT) { continue; }
    seg = &cmd->command.segment;
    
    if (seg->segment == section) {
      if (num == 0) { ncmd = cmd; }
      num++;
    }

    for (j = 0; j < seg->nsects; j++) {
      
      struct bfd_mach_o_section *sect = &seg->sections[j];
      if (sect->bfdsection == section) {
	if (num == 0) { nsect = sect; }
	num++;
      }
    }
  }
  
  *mcommand = ncmd;
  *msection = nsect;
  return num;
}

int bfd_mach_o_lookup_command 
  (bfd *abfd, bfd_mach_o_load_command_type type,
   bfd_mach_o_load_command **mcommand)
{
  struct mach_o_data_struct *md = NULL;
  bfd_mach_o_load_command *ncmd = NULL;
  unsigned int i, num;

  md = abfd->tdata.mach_o_data;

  BFD_ASSERT (md != NULL);
  BFD_ASSERT (mcommand != NULL);

  num = 0;
  for (i = 0; i < md->header.ncmds; i++) {
    struct bfd_mach_o_load_command *cmd = &md->commands[i];
    if (cmd->type != type) { continue; }
    if (num == 0) { ncmd = cmd; }
    num++;
  }

  *mcommand = ncmd;
  return num;
}

#define TARGET_NAME mach_o_be_vec
#define TARGET_STRING "mach-o-be"
#define TARGET_BIG_ENDIAN 1
#define TARGET_ARCHIVE 0

#include "mach-o-target.c"

#undef TARGET_NAME
#undef TARGET_STRING
#undef TARGET_BIG_ENDIAN
#undef TARGET_ARCHIVE

#define TARGET_NAME mach_o_le_vec
#define TARGET_STRING "mach-o-le"
#define TARGET_BIG_ENDIAN 0
#define TARGET_ARCHIVE 0

#include "mach-o-target.c"

#undef TARGET_NAME
#undef TARGET_STRING
#undef TARGET_BIG_ENDIAN
#undef TARGET_ARCHIVE

#define TARGET_NAME mach_o_fat_vec
#define TARGET_STRING "mach-o-fat"
#define TARGET_BIG_ENDIAN 1
#define TARGET_ARCHIVE 1

#include "mach-o-target.c"

#undef TARGET_NAME
#undef TARGET_STRING
#undef TARGET_BIG_ENDIAN
#undef TARGET_ARCHIVE