objfiles.c

早期freebsd实现

#endif
  clear_pc_function_cache ();

  /* The last thing we do is free the objfile struct itself for the
     non-reusable case, or detach from the mapped file for the reusable
     case.  Note that the mmalloc_detach or the mfree is the last thing
     we can do with this objfile. */

#if !defined(NO_MMALLOC) && defined(HAVE_MMAP)

  if (objfile -> flags & OBJF_MAPPED)
    {
      /* Remember the fd so we can close it.  We can't close it before
	 doing the detach, and after the detach the objfile is gone. */
      mmfd = objfile -> mmfd;
      mmalloc_detach (objfile -> md);
      objfile = NULL;
      close (mmfd);
    }

#endif	/* !defined(NO_MMALLOC) && defined(HAVE_MMAP) */

  /* If we still have an objfile, then either we don't support reusable
     objfiles or this one was not reusable.  So free it normally. */

  if (objfile != NULL)
    {
      if (objfile -> name != NULL)
	{
	  mfree (objfile -> md, objfile -> name);
	}
      if (objfile->global_psymbols.list)
	mfree (objfile->md, objfile->global_psymbols.list);
      if (objfile->static_psymbols.list)
	mfree (objfile->md, objfile->static_psymbols.list);
      /* Free the obstacks for non-reusable objfiles */
      obstack_free (&objfile -> psymbol_obstack, 0);
      obstack_free (&objfile -> symbol_obstack, 0);
      obstack_free (&objfile -> type_obstack, 0);
      mfree (objfile -> md, objfile);
      objfile = NULL;
    }
}


/* Free all the object files at once.  */

void
free_all_objfiles ()
{
  struct objfile *objfile, *temp;

  ALL_OBJFILES_SAFE (objfile, temp)
    {
      free_objfile (objfile);
    }
}

/* Many places in gdb want to test just to see if we have any partial
   symbols available.  This function returns zero if none are currently
   available, nonzero otherwise. */

int
have_partial_symbols ()
{
  struct objfile *ofp;

  ALL_OBJFILES (ofp)
    {
      if (ofp -> psymtabs != NULL)
	{
	  return 1;
	}
    }
  return 0;
}

/* Many places in gdb want to test just to see if we have any full
   symbols available.  This function returns zero if none are currently
   available, nonzero otherwise. */

int
have_full_symbols ()
{
  struct objfile *ofp;

  ALL_OBJFILES (ofp)
    {
      if (ofp -> symtabs != NULL)
	{
	  return 1;
	}
    }
  return 0;
}

/* Many places in gdb want to test just to see if we have any minimal
   symbols available.  This function returns zero if none are currently
   available, nonzero otherwise. */

int
have_minimal_symbols ()
{
  struct objfile *ofp;

  ALL_OBJFILES (ofp)
    {
      if (ofp -> msymbols != NULL)
	{
	  return 1;
	}
    }
  return 0;
}

#if !defined(NO_MMALLOC) && defined(HAVE_MMAP)

/* Given the name of a mapped symbol file in SYMSFILENAME, and the timestamp
   of the corresponding symbol file in MTIME, try to open an existing file
   with the name SYMSFILENAME and verify it is more recent than the base
   file by checking it's timestamp against MTIME.

   If SYMSFILENAME does not exist (or can't be stat'd), simply returns -1.

   If SYMSFILENAME does exist, but is out of date, we check to see if the
   user has specified creation of a mapped file.  If so, we don't issue
   any warning message because we will be creating a new mapped file anyway,
   overwriting the old one.  If not, then we issue a warning message so that
   the user will know why we aren't using this existing mapped symbol file.
   In either case, we return -1.

   If SYMSFILENAME does exist and is not out of date, but can't be opened for
   some reason, then prints an appropriate system error message and returns -1.

   Otherwise, returns the open file descriptor.  */

static int
open_existing_mapped_file (symsfilename, mtime, mapped)
     char *symsfilename;
     long mtime;
     int mapped;
{
  int fd = -1;
  struct stat sbuf;

  if (stat (symsfilename, &sbuf) == 0)
    {
      if (sbuf.st_mtime < mtime)
	{
	  if (!mapped)
	    {
	      warning ("mapped symbol file `%s' is out of date, ignored it",
		       symsfilename);
	    }
	}
      else if ((fd = open (symsfilename, O_RDWR)) < 0)
	{
	  if (error_pre_print)
	    {
	      printf (error_pre_print);
	    }
	  print_sys_errmsg (symsfilename, errno);
	}
    }
  return (fd);
}

/* Look for a mapped symbol file that corresponds to FILENAME and is more
   recent than MTIME.  If MAPPED is nonzero, the user has asked that gdb
   use a mapped symbol file for this file, so create a new one if one does
   not currently exist.

   If found, then return an open file descriptor for the file, otherwise
   return -1.

   This routine is responsible for implementing the policy that generates
   the name of the mapped symbol file from the name of a file containing
   symbols that gdb would like to read.  Currently this policy is to append
   ".syms" to the name of the file.

   This routine is also responsible for implementing the policy that
   determines where the mapped symbol file is found (the search path).
   This policy is that when reading an existing mapped file, a file of
   the correct name in the current directory takes precedence over a
   file of the correct name in the same directory as the symbol file.
   When creating a new mapped file, it is always created in the current
   directory.  This helps to minimize the chances of a user unknowingly
   creating big mapped files in places like /bin and /usr/local/bin, and
   allows a local copy to override a manually installed global copy (in
   /bin for example).  */

static int
open_mapped_file (filename, mtime, mapped)
     char *filename;
     long mtime;
     int mapped;
{
  int fd;
  char *symsfilename;

  /* First try to open an existing file in the current directory, and
     then try the directory where the symbol file is located. */

  symsfilename = concat ("./", basename (filename), ".syms", (char *) NULL);
  if ((fd = open_existing_mapped_file (symsfilename, mtime, mapped)) < 0)
    {
      free (symsfilename);
      symsfilename = concat (filename, ".syms", (char *) NULL);
      fd = open_existing_mapped_file (symsfilename, mtime, mapped);
    }

  /* If we don't have an open file by now, then either the file does not
     already exist, or the base file has changed since it was created.  In
     either case, if the user has specified use of a mapped file, then
     create a new mapped file, truncating any existing one.  If we can't
     create one, print a system error message saying why we can't.

     By default the file is rw for everyone, with the user's umask taking
     care of turning off the permissions the user wants off. */

  if ((fd < 0) && mapped)
    {
      free (symsfilename);
      symsfilename = concat ("./", basename (filename), ".syms",
			     (char *) NULL);
      if ((fd = open (symsfilename, O_RDWR | O_CREAT | O_TRUNC, 0666)) < 0)
	{
	  if (error_pre_print)
	    {
	      printf (error_pre_print);
	    }
	  print_sys_errmsg (symsfilename, errno);
	}
    }

  free (symsfilename);
  return (fd);
}

/* Return the base address at which we would like the next objfile's
   mapped data to start.

   For now, we use the kludge that the configuration specifies a base
   address to which it is safe to map the first mmalloc heap, and an
   increment to add to this address for each successive heap.  There are
   a lot of issues to deal with here to make this work reasonably, including:

     Avoid memory collisions with existing mapped address spaces

     Reclaim address spaces when their mmalloc heaps are unmapped

     When mmalloc heaps are shared between processes they have to be
     mapped at the same addresses in each

     Once created, a mmalloc heap that is to be mapped back in must be
     mapped at the original address.  I.E. each objfile will expect to
     be remapped at it's original address.  This becomes a problem if
     the desired address is already in use.

     etc, etc, etc.

 */


static CORE_ADDR
map_to_address ()
{

#if defined(MMAP_BASE_ADDRESS) && defined (MMAP_INCREMENT)

  static CORE_ADDR next = MMAP_BASE_ADDRESS;
  CORE_ADDR mapto = next;

  next += MMAP_INCREMENT;
  return (mapto);

#else

  return (0);

#endif

}

#endif	/* !defined(NO_MMALLOC) && defined(HAVE_MMAP) */