自学教程：C++ unexec_error函数代码示例

/* Copy a LC_SEGMENT load command other than the __DATA segment from   the input file to the output file, adjusting the file offset of the   segment and the file offsets of sections contained in it.  */static voidcopy_segment (struct load_command *lc){  struct segment_command *scp = (struct segment_command *) lc;  unsigned long old_fileoff = scp->fileoff;  struct section *sectp;  int j;  scp->fileoff = curr_file_offset;  sectp = (struct section *) (scp + 1);  for (j = 0; j < scp->nsects; j++)    {      sectp->offset += curr_file_offset - old_fileoff;      sectp++;    }  printf ("Writing segment %-16.16s @ %#8lx (%#8lx/%#8lx @ %#10lx)/n",	  scp->segname, (long) (scp->fileoff), (long) (scp->filesize),	  (long) (scp->vmsize), (long) (scp->vmaddr));  if (!unexec_copy (scp->fileoff, old_fileoff, scp->filesize))    unexec_error ("cannot copy segment from input to output file");  curr_file_offset += ROUNDUP_TO_PAGE_BOUNDARY (scp->filesize);  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))    unexec_error ("cannot write load command to header");  curr_header_offset += lc->cmdsize;}

/* Take a snapshot of Emacs and make a Mach-O format executable file   from it.  The file names of the output and input files are outfile   and infile, respectively.  The three other parameters are   ignored.  */voidunexec (const char *outfile, const char *infile){  if (in_dumped_exec)    unexec_error ("Unexec from a dumped executable is not supported.");  pagesize = getpagesize ();  infd = open (infile, O_RDONLY, 0);  if (infd < 0)    {      unexec_error ("cannot open input file `%s'", infile);    }  outfd = open (outfile, O_WRONLY | O_TRUNC | O_CREAT, 0755);  if (outfd < 0)    {      close (infd);      unexec_error ("cannot open output file `%s'", outfile);    }  build_region_list ();  read_load_commands ();  find_emacs_zone_regions ();  unexec_regions_merge ();  in_dumped_exec = 1;  dump_it ();  close (outfd);}

/* Copy a LC_SEGMENT load command for the EMACS_READ_ONLY segment from   the input file to the output file, adjusting the file offset of the   segment and the file offsets of sections contained in it.  The VM   protection is changed to read-only, and the sections are dumped   from memory.  */static voidcopy_emacs_read_only_segment (struct load_command *lc){  struct segment_command *scp = (struct segment_command *) lc;  unsigned long old_fileoff = scp->fileoff;  struct section *sectp;  int j;  scp->fileoff = curr_file_offset;  scp->maxprot = scp->initprot = VM_PROT_READ;  printf ("Writing segment %-16.16s @ %#8lx (%#8lx/%#8lx @ %#10lx)/n",	  scp->segname, (long) (scp->fileoff), (long) (scp->filesize),	  (long) (scp->vmsize), (long) (scp->vmaddr));  sectp = (struct section *) (scp + 1);  for (j = 0; j < scp->nsects; j++)    {      sectp->offset += curr_file_offset - old_fileoff;      if (!unexec_write (sectp->offset, (void *) sectp->addr, sectp->size))	unexec_error ("cannot write section %.16s", sectp->sectname);      printf ("        section %-16.16s at %#8lx - %#8lx (sz: %#8lx)/n",	      sectp->sectname, (long) (sectp->offset),	      (long) (sectp->offset + sectp->size), (long) (sectp->size));      sectp++;    }  curr_file_offset += ROUNDUP_TO_PAGE_BOUNDARY (scp->filesize);  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))    unexec_error ("cannot write load command to header");  curr_header_offset += lc->cmdsize;}

/* Rebase r_address in the relocation table.  */static voidrebase_reloc_address (off_t reloff, int nrel, long linkedit_delta, long diff){  int i;  struct relocation_info reloc_info;  struct scattered_relocation_info *sc_reloc_info    = (struct scattered_relocation_info *) &reloc_info;  for (i = 0; i < nrel; i++, reloff += sizeof (reloc_info))    {      if (lseek (infd, reloff - linkedit_delta, L_SET)	  != reloff - linkedit_delta)	unexec_error ("rebase_reloc_table: cannot seek to reloc_info");      if (!unexec_read (&reloc_info, sizeof (reloc_info)))	unexec_error ("rebase_reloc_table: cannot read reloc_info");      if (sc_reloc_info->r_scattered == 0	  && reloc_info.r_type == GENERIC_RELOC_VANILLA)	{	  reloc_info.r_address -= diff;	  if (!unexec_write (reloff, &reloc_info, sizeof (reloc_info)))	    unexec_error ("rebase_reloc_table: cannot write reloc_info");	}    }}

static voidunexec_write (int fd, long position, char *buf, int bytes){  int n_written;  int remains = bytes;  position = unexec_seek (fd, position);  if (bytes < 0)    unexec_error ("Attempted write of %d bytes in %s",                  0, (char *) bytes, "unexec() output file", 0);  errno = 0;  while (remains > 0)    {      n_written = write (fd, buf, remains);      if (n_written <= 0)        unexec_error ("Write failed for 0x%x bytes at offset 0x%x in %s",                      1, (char *) bytes, (char *) position,                      "unexec() output file");      buf += n_written;      remains -= n_written;    }  return;}

static voidunexec_read (int fd, long position, char *buf, int bytes){  int n_read;  int remains = bytes;  position = unexec_seek (fd, position);  if (bytes < 0)    unexec_error ("Attempted read of %d bytes", 0, (char *) bytes, 0, 0);  errno = 0;  while (remains > 0)    {      n_read = read (fd, buf, remains);      if (n_read <= 0)        unexec_error ("Read failed for 0x%x bytes at offset 0x%x in %s",                      1, (char *) bytes, (char *) position,                      "unexec() output file");      buf += n_read;      remains -= n_read;    }  return;}

/* Fix up relocation entries. */static voidunrelocate (const char *name, off_t reloff, int nrel, vm_address_t base){  int i, unreloc_count;  struct relocation_info reloc_info;  struct scattered_relocation_info *sc_reloc_info    = (struct scattered_relocation_info *) &reloc_info;  vm_address_t location;  for (unreloc_count = 0, i = 0; i < nrel; i++)    {      if (lseek (infd, reloff, L_SET) != reloff)	unexec_error ("unrelocate: %s:%d cannot seek to reloc_info", name, i);      if (!unexec_read (&reloc_info, sizeof (reloc_info)))	unexec_error ("unrelocate: %s:%d cannot read reloc_info", name, i);      reloff += sizeof (reloc_info);      if (sc_reloc_info->r_scattered == 0)	switch (reloc_info.r_type)	  {	  case GENERIC_RELOC_VANILLA:	    location = base + reloc_info.r_address;	    if (location >= data_segment_scp->vmaddr		&& location < (data_segment_scp->vmaddr			       + data_segment_scp->vmsize))	      {		off_t src_off = data_segment_old_fileoff		  + (location - data_segment_scp->vmaddr);		off_t dst_off = data_segment_scp->fileoff		  + (location - data_segment_scp->vmaddr);		if (!unexec_copy (dst_off, src_off, 1 << reloc_info.r_length))		  unexec_error ("unrelocate: %s:%d cannot copy original value",				name, i);		unreloc_count++;	      }	    break;	  default:	    unexec_error ("unrelocate: %s:%d cannot handle type = %d",			  name, i, reloc_info.r_type);	  }      else	switch (sc_reloc_info->r_type)	  {#if defined (__ppc__)	  case PPC_RELOC_PB_LA_PTR:	    /* nothing to do for prebound lazy pointer */	    break;#endif	  default:	    unexec_error ("unrelocate: %s:%d cannot handle scattered type = %d",			  name, i, sc_reloc_info->r_type);	  }    }  if (nrel > 0)    printf ("Fixed up %d/%d %s relocation entries in data segment./n",	    unreloc_count, nrel, name);}

/* Copy a LC_DYLD_INFO(_ONLY) load command from the input file to the output   file, adjusting the file offset fields.  */static voidcopy_dyld_info (struct load_command *lc, long delta){  struct dyld_info_command *dip = (struct dyld_info_command *) lc;  if (dip->rebase_off > 0)    dip->rebase_off += delta;  if (dip->bind_off > 0)    dip->bind_off += delta;  if (dip->weak_bind_off > 0)    dip->weak_bind_off += delta;  if (dip->lazy_bind_off > 0)    dip->lazy_bind_off += delta;  if (dip->export_off > 0)    dip->export_off += delta;  printf ("Writing ");  print_load_command_name (lc->cmd);  printf (" command/n");  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))    unexec_error ("cannot write dyld info command to header");  curr_header_offset += lc->cmdsize;}

/* Copy a LC_DYSYMTAB load command from the input file to the output   file, adjusting the file offset fields.  */static voidcopy_dysymtab (struct load_command *lc, long delta){  struct dysymtab_command *dstp = (struct dysymtab_command *) lc;  vm_address_t base;#ifdef _LP64  /* First writable segment address.  */  base = data_segment_scp->vmaddr;#else  /* First segment address in the file (unless MH_SPLIT_SEGS set). */  base = 0;#endif  unrelocate ("local", dstp->locreloff, dstp->nlocrel, base);  unrelocate ("external", dstp->extreloff, dstp->nextrel, base);  if (dstp->nextrel > 0) {    dstp->extreloff += delta;  }  if (dstp->nlocrel > 0) {    dstp->locreloff += delta;  }  if (dstp->nindirectsyms > 0)    dstp->indirectsymoff += delta;  printf ("Writing LC_DYSYMTAB command/n");  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))    unexec_error ("cannot write symtab command to header");  curr_header_offset += lc->cmdsize;}

static voidunexec_fchmod (int fd, int mode){  errno = 0;  if (-1 == fchmod (fd, mode))    unexec_error ("fchmod() failed for descriptor %d", 1, (char *) fd, 0, 0);  return;}

static voidunexec_fstat (int fd, struct stat *statptr){  errno = 0;  if (-1 == fstat (fd, statptr))    unexec_error ("fstat() failed for descriptor %d", 1, (char *) fd, 0, 0);  return;}

/* Take a snapshot of Gcl and make a Mach-O format executable file   from it.  The file names of the output and input files are outfile   and infile, respectively.  The three other parameters are   ignored.  */voidunexec (char *outfile, char *infile, void *start_data, void *start_bss,        void *entry_address) {  reset_unexec_globals();    pagesize = getpagesize ();  if ((infd = open (infile, O_RDONLY, 0)) < 0)    unexec_error ("cannot open input file `%s'", infile);  if ((outfd = open (outfile, O_WRONLY | O_TRUNC | O_CREAT, 0755)) < 0) {    close (infd);    unexec_error ("cannot open output file `%s'", outfile);  }  read_load_commands_and_dump();  close (outfd);}

static longunexec_seek (int fd, long position){  long seek_value;  if (fd <= 0)    unexec_error ("No file open in which to seek", 0, 0, 0, 0);  errno = 0;  if (position < 0)    seek_value = (long) lseek (fd, 0, L_INCR);  else    seek_value = (long) lseek (fd, position, L_SET);  if (seek_value < 0)    unexec_error ("Failed to do a seek to 0x%x in %s", 1,                  (char *) position, "unexec() output file", 0);  return seek_value;}

/* Copy other kinds of load commands from the input file to the output   file, ones that do not require adjustments of file offsets.  */static voidcopy_other (struct load_command *lc){  printf ("Writing ");  print_load_command_name (lc->cmd);  printf (" command/n");  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))    unexec_error ("cannot write symtab command to header");  curr_header_offset += lc->cmdsize;}

/* Copy a LC_SYMTAB load command from the input file to the output   file, adjusting the file offset fields.  */static voidcopy_symtab (struct load_command *lc, long delta){  struct symtab_command *stp = (struct symtab_command *) lc;  stp->symoff += delta;  stp->stroff += delta;  printf ("Writing LC_SYMTAB command/n");  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))    unexec_error ("cannot write symtab command to header");  curr_header_offset += lc->cmdsize;}

static voidfind_emacs_zone_regions (void){  num_unexec_regions = 0;  emacs_zone->introspect->enumerator (mach_task_self (), 0,				      MALLOC_PTR_REGION_RANGE_TYPE				      | MALLOC_ADMIN_REGION_RANGE_TYPE,				      (vm_address_t) emacs_zone,				      unexec_reader,				      unexec_regions_recorder);  if (num_unexec_regions == MAX_UNEXEC_REGIONS)    unexec_error ("find_emacs_zone_regions: too many regions");}

/* Copy a LC_TWOLEVEL_HINTS load command from the input file to the output   file, adjusting the file offset fields.  */static voidcopy_twolevelhints (struct load_command *lc, long delta){  struct twolevel_hints_command *tlhp = (struct twolevel_hints_command *) lc;  if (tlhp->nhints > 0) {    tlhp->offset += delta;  }  printf ("Writing LC_TWOLEVEL_HINTS command/n");  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))    unexec_error ("cannot write two level hint command to header");  curr_header_offset += lc->cmdsize;}

static intunexec_open (char *filename, int flag, int mode){  int fd;  errno = 0;  fd = open (filename, flag, mode);  if (fd < 0)    {      unexec_error ("Failure opening file %s", 1, (void *) filename, 0, 0);      return -1;    }  else    return fd;}

/* Copy a LC_FUNCTION_STARTS/LC_DATA_IN_CODE/LC_DYLIB_CODE_SIGN_DRS   load command from the input file to the output file, adjusting the   data offset field.  */static voidcopy_linkedit_data (struct load_command *lc, long delta){  struct linkedit_data_command *ldp = (struct linkedit_data_command *) lc;  if (ldp->dataoff > 0)    ldp->dataoff += delta;  printf ("Writing ");  print_load_command_name (lc->cmd);  printf (" command/n");  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))    unexec_error ("cannot write linkedit data command to header");  curr_header_offset += lc->cmdsize;}

//.........这里部分代码省略.........    printf ("copying %#lx bytes of new text from %#lx to position %#lx/n",            newtext_size, old_dataddr, TEXT_OFFSET(new_hdr) + old_dataddr);#endif    unexec_write (new_fd, TEXT_OFFSET(new_hdr) + old_dataddr,                  (caddr_t)old_dataddr, newtext_size);#ifdef DEBUG    printf ("new DATA_OFFSET is %#lx/n", new_datoff);#endif    /*     * Copy the part of the old data segment which will be data     * in the new executable (before the dynamic stuff)     * from the running image.     */#ifdef DEBUG    printf ("copying %#lx bytes of data from %#lx to position %#lx/n",            newdata1_size, new_dataddr, new_datoff);#endif    unexec_write (new_fd, new_datoff, (caddr_t)new_dataddr, newdata1_size);    /* copy the dynamic part of the data segment from the old executable */    if (dyn_size)      {#ifdef DEBUG        printf ("copying %#lx bytes of dyn data from executable"                " at address %#lx to position %#lx/n",                 dyn_size, dynamic_beg, new_datoff + newdata1_size);#endif        unexec_copy (new_fd, old_fd, old_datoff + newtext_size + newdata1_size,                     new_datoff + newdata1_size, dyn_size);      }    /* copy remaining data (old bss) from the running image */#ifdef DEBUG    printf ("copying %#lx bytes of data from %#lx to position %#lx/n",            newdata2_size, new_dataddr + newdata1_size + dyn_size,            new_datoff + newdata1_size + dyn_size);#endif    unexec_write (new_fd, new_datoff + newdata1_size + dyn_size,                  (caddr_t)(new_dataddr + newdata1_size + dyn_size),                  newdata2_size);    /* pad out the data segment */#ifdef DEBUG    printf ( "pad size is %#x/n", pad_size);#endif    unexec_pad (new_fd, pad_size);        /* Finally, copy the rest of the junk from the old file. */#ifdef DEBUG    printf ("Copying %#lx bytes of junk from %#lx (old) to %#lx (new)/n",            old_buf.st_size - old_mcaloff, old_mcaloff, new_mcaloff);#endif    unexec_copy (new_fd, old_fd, old_mcaloff, new_mcaloff,                 old_buf.st_size - old_mcaloff);    {	long			curpos, offset;	struct _debug_header	dhdr;	int			new_header_delta;	new_header_delta = LESYM_OFFSET(new_hdr) - LESYM_OFFSET(old_hdr);	if ((new_header_delta > 0) &&	    ((offset = EXT_OFFSET(old_hdr)) > 0))	{	    curpos = lseek(new_fd, 0, SEEK_CUR);	    lseek(old_fd, offset, 0);	    if (read(old_fd, &dhdr, sizeof(dhdr)) == sizeof(dhdr))	    {		dhdr.header_offset += new_header_delta;		dhdr.gntt_offset += new_header_delta;		dhdr.lntt_offset += new_header_delta;		dhdr.slt_offset += new_header_delta;		dhdr.vt_offset += new_header_delta;		dhdr.xt_offset += new_header_delta;		lseek(new_fd, EXT_OFFSET(new_hdr), SEEK_SET);		if (write(new_fd, &dhdr, sizeof(dhdr)) != sizeof(dhdr))		{		    unexec_error("Unable to write debug information to /"%s/"/n",				 1, new_name);		}		lseek(new_fd, curpos, SEEK_SET);	    }	    else	    {		unexec_error("Unable to read debug information from /"%s/"/n",			     1, old_name);	    }	}    }  }         /* make the output file executable -- then quit */  unexec_fchmod (new_fd, 0755);  close (old_fd);  close (new_fd);  return 0;}

/* Copy a LC_SEGMENT load command for the __DATA segment in the input   file to the output file.  We assume that only one such segment load   command exists in the input file and it contains the sections   __data, __bss, __common, __la_symbol_ptr, __nl_symbol_ptr, and   __dyld.  The first three of these should be dumped from memory and   the rest should be copied from the input file.  Note that the   sections __bss and __common contain no data in the input file   because their flag fields have the value S_ZEROFILL.  Dumping these   from memory makes it necessary to adjust file offset fields in   subsequently dumped load commands.  Then, create new __DATA segment   load commands for regions on the region list other than the one   corresponding to the __DATA segment in the input file.  */static voidcopy_data_segment (struct load_command *lc){  struct segment_command *scp = (struct segment_command *) lc;  struct section *sectp;  int j;  unsigned long header_offset, old_file_offset;  /* The new filesize of the segment is set to its vmsize because data     blocks for segments must start at region boundaries.  Note that     this may leave unused locations at the end of the segment data     block because the total of the sizes of all sections in the     segment is generally smaller than vmsize.  */  scp->filesize = scp->vmsize;  printf ("Writing segment %-16.16s @ %#8lx (%#8lx/%#8lx @ %#10lx)/n",	  scp->segname, curr_file_offset, (long)(scp->filesize),	  (long)(scp->vmsize), (long) (scp->vmaddr));  /* Offsets in the output file for writing the next section structure     and segment data block, respectively.  */  header_offset = curr_header_offset + sizeof (struct segment_command);  sectp = (struct section *) (scp + 1);  for (j = 0; j < scp->nsects; j++)    {      old_file_offset = sectp->offset;      sectp->offset = sectp->addr - scp->vmaddr + curr_file_offset;      /* The __data section is dumped from memory.  The __bss and	 __common sections are also dumped from memory but their flag	 fields require changing (from S_ZEROFILL to S_REGULAR).  The	 other three kinds of sections are just copied from the input	 file.  */      if (strncmp (sectp->sectname, SECT_DATA, 16) == 0)	{	  extern char my_edata[];	  unsigned long my_size;	  /* The __data section is basically dumped from memory.  But	     initialized data in statically linked libraries are	     copied from the input file.  In particular,	     add_image_hook.names and add_image_hook.pointers stored	     by libarclite_macosx.a, are restored so that they will be	     reinitialized when the dumped binary is executed.  */	  my_size = (unsigned long)my_edata - sectp->addr;	  if (!(sectp->addr <= (unsigned long)my_edata		&& my_size <= sectp->size))	    unexec_error ("my_edata is not in section %s", SECT_DATA);	  if (!unexec_write (sectp->offset, (void *) sectp->addr, my_size))	    unexec_error ("cannot write section %s", SECT_DATA);	  if (!unexec_copy (sectp->offset + my_size, old_file_offset + my_size,			    sectp->size - my_size))	    unexec_error ("cannot copy section %s", SECT_DATA);	  if (!unexec_write (header_offset, sectp, sizeof (struct section)))	    unexec_error ("cannot write section %s's header", SECT_DATA);	}      else if (strncmp (sectp->sectname, SECT_COMMON, 16) == 0)	{	  sectp->flags = S_REGULAR;	  if (!unexec_write (sectp->offset, (void *) sectp->addr, sectp->size))	    unexec_error ("cannot write section %.16s", sectp->sectname);	  if (!unexec_write (header_offset, sectp, sizeof (struct section)))	    unexec_error ("cannot write section %.16s's header", sectp->sectname);	}      else if (strncmp (sectp->sectname, SECT_BSS, 16) == 0)	{	  extern char *my_endbss_static;	  unsigned long my_size;	  sectp->flags = S_REGULAR;	  /* Clear uninitialized local variables in statically linked	     libraries.  In particular, function pointers stored by	     libSystemStub.a, which is introduced in Mac OS X 10.4 for	     binary compatibility with respect to long double, are	     cleared so that they will be reinitialized when the	     dumped binary is executed on other versions of OS.  */	  my_size = (unsigned long)my_endbss_static - sectp->addr;	  if (!(sectp->addr <= (unsigned long)my_endbss_static		&& my_size <= sectp->size))	    unexec_error ("my_endbss_static is not in section %.16s",			  sectp->sectname);	  if (!unexec_write (sectp->offset, (void *) sectp->addr, my_size))	    unexec_error ("cannot write section %.16s", sectp->sectname);	  if (!unexec_write_zero (sectp->offset + my_size,				  sectp->size - my_size))	    unexec_error ("cannot write section %.16s", sectp->sectname);	  if (!unexec_write (header_offset, sectp, sizeof (struct section)))//.........这里部分代码省略.........

/* Copy a LC_DYSYMTAB load command from the input file to the output   file, adjusting the file offset fields.  */static voidcopy_dysymtab (struct load_command *lc, long delta){  struct dysymtab_command *dstp = (struct dysymtab_command *) lc;  vm_address_t base;#ifdef _LP64#if __ppc64__  {    int i;    base = 0;    for (i = 0; i < nlc; i++)      if (lca[i]->cmd == LC_SEGMENT)	{	  struct segment_command *scp = (struct segment_command *) lca[i];	  if (scp->vmaddr + scp->vmsize > 0x100000000	      && (scp->initprot & VM_PROT_WRITE) != 0)	    {	      base = data_segment_scp->vmaddr;	      break;	    }	}  }#else  /* First writable segment address.  */  base = data_segment_scp->vmaddr;#endif#else  /* First segment address in the file (unless MH_SPLIT_SEGS set). */  base = 0;#endif  unrelocate ("local", dstp->locreloff, dstp->nlocrel, base);  unrelocate ("external", dstp->extreloff, dstp->nextrel, base);  if (dstp->nextrel > 0) {    dstp->extreloff += delta;  }  if (dstp->nlocrel > 0) {    dstp->locreloff += delta;  }  if (dstp->nindirectsyms > 0)    dstp->indirectsymoff += delta;  printf ("Writing LC_DYSYMTAB command/n");  if (!unexec_write (curr_header_offset, lc, lc->cmdsize))    unexec_error ("cannot write symtab command to header");  curr_header_offset += lc->cmdsize;#if __ppc64__  /* Check if the relocation base needs to be changed.  */  if (base == 0)    {      vm_address_t newbase = 0;      int i;      for (i = 0; i < num_unexec_regions; i++)	if (unexec_regions[i].range.address + unexec_regions[i].range.size	    > 0x100000000)	  {	    newbase = data_segment_scp->vmaddr;	    break;	  }      if (newbase)	{	  rebase_reloc_address (dstp->locreloff, dstp->nlocrel, delta, newbase);	  rebase_reloc_address (dstp->extreloff, dstp->nextrel, delta, newbase);	}    }#endif}

/* Read header and load commands from input file.  Store the latter in   the global array lca.  Store the total number of load commands in   global variable nlc.  */static voidread_load_commands (void){  int i;  if (!unexec_read (&mh, sizeof (struct mach_header)))    unexec_error ("cannot read mach-o header");  if (mh.magic != MH_MAGIC)    unexec_error ("input file not in Mach-O format");  if (mh.filetype != MH_EXECUTE)    unexec_error ("input Mach-O file is not an executable object file");#if VERBOSE  printf ("--- Header Information ---/n");  printf ("Magic = 0x%08x/n", mh.magic);  printf ("CPUType = %d/n", mh.cputype);  printf ("CPUSubType = %d/n", mh.cpusubtype);  printf ("FileType = 0x%x/n", mh.filetype);  printf ("NCmds = %d/n", mh.ncmds);  printf ("SizeOfCmds = %d/n", mh.sizeofcmds);  printf ("Flags = 0x%08x/n", mh.flags);#endif  nlc = mh.ncmds;  lca = malloc (nlc * sizeof *lca);  for (i = 0; i < nlc; i++)    {      struct load_command lc;      /* Load commands are variable-size: so read the command type and	 size first and then read the rest.  */      if (!unexec_read (&lc, sizeof (struct load_command)))        unexec_error ("cannot read load command");      lca[i] = malloc (lc.cmdsize);      memcpy (lca[i], &lc, sizeof (struct load_command));      if (!unexec_read (lca[i] + 1, lc.cmdsize - sizeof (struct load_command)))        unexec_error ("cannot read content of load command");      if (lc.cmd == LC_SEGMENT)	{	  struct segment_command *scp = (struct segment_command *) lca[i];	  if (scp->vmaddr + scp->vmsize > infile_lc_highest_addr)	    infile_lc_highest_addr = scp->vmaddr + scp->vmsize;	  if (strncmp (scp->segname, SEG_TEXT, 16) == 0)	    {	      struct section *sectp = (struct section *) (scp + 1);	      int j;	      for (j = 0; j < scp->nsects; j++)		if (sectp->offset < text_seg_lowest_offset)		  text_seg_lowest_offset = sectp->offset;	    }	}    }  printf ("Highest address of load commands in input file: %#8lx/n",	  (unsigned long)infile_lc_highest_addr);  printf ("Lowest offset of all sections in __TEXT segment: %#8lx/n",	  text_seg_lowest_offset);  printf ("--- List of Load Commands in Input File ---/n");  printf ("# cmd              cmdsize name                address     size/n");  for (i = 0; i < nlc; i++)    {      printf ("%1d ", i);      print_load_command (lca[i]);    }}

/* Build the list of regions that need to be dumped.  Regions with   addresses above VM_DATA_TOP are omitted.  Adjacent regions with   identical protection are merged.  Note that non-writable regions   cannot be omitted because they some regions created at run time are   read-only.  */static voidbuild_region_list (void){  task_t target_task = mach_task_self ();  vm_address_t address = (vm_address_t) 0;  vm_size_t size;  struct vm_region_basic_info info;  mach_msg_type_number_t info_count = VM_REGION_BASIC_INFO_COUNT;  mach_port_t object_name;  struct region_t *r;#if VERBOSE  printf ("--- List of All Regions ---/n");  printf ("   address     size prot maxp/n");#endif  while (vm_region (target_task, &address, &size, VM_REGION_BASIC_INFO,		    (vm_region_info_t) &info, &info_count, &object_name)	 == KERN_SUCCESS && info_count == VM_REGION_BASIC_INFO_COUNT)    {      /* Done when we reach addresses of shared libraries, which are	 loaded in high memory.  */      if (address >= VM_DATA_TOP)	break;#if VERBOSE      print_region (address, size, info.protection, info.max_protection);#endif      /* If a region immediately follows the previous one (the one	 most recently added to the list) and has identical	 protection, merge it with the latter.  Otherwise create a	 new list element for it.  */      if (region_list_tail	  && info.protection == region_list_tail->protection	  && info.max_protection == region_list_tail->max_protection	  && region_list_tail->address + region_list_tail->size == address)	{	  region_list_tail->size += size;	}      else	{	  r = malloc (sizeof *r);	  if (!r)	    unexec_error ("cannot allocate region structure");	  r->address = address;	  r->size = size;	  r->protection = info.protection;	  r->max_protection = info.max_protection;	  r->next = 0;	  if (region_list_head == 0)	    {	      region_list_head = r;	      region_list_tail = r;	    }	  else	    {	      region_list_tail->next = r;	      region_list_tail = r;	    }	  /* Deallocate (unused) object name returned by	     vm_region.  */	  if (object_name != MACH_PORT_NULL)	    mach_port_deallocate (target_task, object_name);	}      address += size;    }  printf ("--- List of Regions to be Dumped ---/n");  print_region_list ();}

/* Loop through all load commands and dump them.  Then write the Mach   header.  */static voiddump_it (void){  int i;  long linkedit_delta = 0;  printf ("--- Load Commands written to Output File ---/n");  for (i = 0; i < nlc; i++)    switch (lca[i]->cmd)      {      case LC_SEGMENT:	{	  struct segment_command *scp = (struct segment_command *) lca[i];	  if (strncmp (scp->segname, SEG_DATA, 16) == 0)	    {	      /* save data segment file offset and segment_command for		 unrelocate */	      if (data_segment_old_fileoff)		unexec_error ("cannot handle multiple DATA segments"			      " in input file");	      data_segment_old_fileoff = scp->fileoff;	      data_segment_scp = scp;	      copy_data_segment (lca[i]);	    }	  else if (strncmp (scp->segname, EMACS_READ_ONLY_SEGMENT, 16) == 0)	    {	      copy_emacs_read_only_segment (lca[i]);	    }	  else	    {	      if (strncmp (scp->segname, SEG_LINKEDIT, 16) == 0)		{		  if (linkedit_delta)		    unexec_error ("cannot handle multiple LINKEDIT segments"				  " in input file");		  linkedit_delta = curr_file_offset - scp->fileoff;		}	      copy_segment (lca[i]);	    }	}	break;      case LC_SYMTAB:	copy_symtab (lca[i], linkedit_delta);	break;      case LC_DYSYMTAB:	copy_dysymtab (lca[i], linkedit_delta);	break;      case LC_TWOLEVEL_HINTS:	copy_twolevelhints (lca[i], linkedit_delta);	break;#ifdef LC_DYLD_INFO      case LC_DYLD_INFO:      case LC_DYLD_INFO_ONLY:	copy_dyld_info (lca[i], linkedit_delta);	break;#endif#ifdef LC_FUNCTION_STARTS      case LC_FUNCTION_STARTS:#ifdef LC_DATA_IN_CODE      case LC_DATA_IN_CODE:#endif#ifdef LC_DYLIB_CODE_SIGN_DRS      case LC_DYLIB_CODE_SIGN_DRS:#endif	copy_linkedit_data (lca[i], linkedit_delta);	break;#endif      default:	copy_other (lca[i]);	break;      }  if (curr_header_offset > text_seg_lowest_offset)    unexec_error ("not enough room for load commands for new __DATA segments");  printf ("%ld unused bytes follow Mach-O header/n",	  text_seg_lowest_offset - curr_header_offset);  mh.sizeofcmds = curr_header_offset - sizeof (struct mach_header);  if (!unexec_write (0, &mh, sizeof (struct mach_header)))    unexec_error ("cannot write final header contents");}