incremen.c

gnu tar 源码包。 tar 软件是 Unix 系统下的一个打包软件

  /* Prepare space for new dumpdir */
  new_dump = xmalloc (len);
  new_dump_ptr = new_dump;

  /* Fill in the dumpdir template */
  for (i = 0; i < dirsize; i++)
    {
      const char *loc = dumpdir_locate (dump, array[i]);
      if (loc)
	{
	  if (directory->tagfile)
	    *new_dump_ptr = strcmp (directory->tagfile, array[i]) == 0 ?
		                ' ' : 'I';
	  else
	    *new_dump_ptr = ' ';
	  new_dump_ptr++;
	}
      else if (directory->tagfile)
	*new_dump_ptr++ = strcmp (directory->tagfile, array[i]) == 0 ?
		               ' ' : 'I';
      else
	*new_dump_ptr++ = 'Y'; /* New entry */

      /* Copy the file name */
      for (p = array[i]; (*new_dump_ptr++ = *p++); )
	;
    }
  *new_dump_ptr = 0;
  directory->idump = directory->dump;
  directory->dump = dumpdir_create0 (new_dump, NULL);
  free (array);
}

/* Recursively scan the given directory. */
static const char *
scan_directory (char *dir, dev_t device)
{
  char *dirp = savedir (dir);	/* for scanning directory */
  char *name_buffer;		/* directory, `/', and directory member */
  size_t name_buffer_size;	/* allocated size of name_buffer, minus 2 */
  size_t name_length;		/* used length in name_buffer */
  struct stat stat_data;
  struct directory *directory;

  if (! dirp)
    savedir_error (dir);

  name_buffer_size = strlen (dir) + NAME_FIELD_SIZE;
  name_buffer = xmalloc (name_buffer_size + 2);
  strcpy (name_buffer, dir);
  if (! ISSLASH (dir[strlen (dir) - 1]))
    strcat (name_buffer, "/");
  name_length = strlen (name_buffer);

  if (deref_stat (dereference_option, name_buffer, &stat_data))
    {
      stat_diag (name_buffer);
      /* FIXME: used to be
           children = CHANGED_CHILDREN;
	 but changed to: */
      free (name_buffer);
      free (dirp);
      return NULL;
    }

  directory = procdir (name_buffer, &stat_data, device, NO_CHILDREN, false,
		       NULL);

  if (dirp && directory->children != NO_CHILDREN)
    {
      char *entry;	/* directory entry being scanned */
      size_t entrylen;	/* length of directory entry */
      dumpdir_iter_t itr;

      makedumpdir (directory, dirp);

      for (entry = dumpdir_first (directory->dump, 1, &itr);
	   entry;
	   entry = dumpdir_next (itr))
	{
	  entrylen = strlen (entry);
	  if (name_buffer_size <= entrylen - 1 + name_length)
	    {
	      do
		name_buffer_size += NAME_FIELD_SIZE;
	      while (name_buffer_size <= entrylen - 1 + name_length);
	      name_buffer = xrealloc (name_buffer, name_buffer_size + 2);
	    }
	  strcpy (name_buffer + name_length, entry + 1);

	  if (*entry == 'I') /* Ignored entry */
	    *entry = 'N';
	  else if (excluded_name (name_buffer))
	    *entry = 'N';
	  else
	    {
	      if (deref_stat (dereference_option, name_buffer, &stat_data))
		{
		  stat_diag (name_buffer);
		  *entry = 'N';
		  continue;
		}

	      if (S_ISDIR (stat_data.st_mode))
		{
		  *entry = 'D';
		  procdir (name_buffer, &stat_data, device,
			   directory->children,
			   verbose_option, entry);
		}

	      else if (one_file_system_option && device != stat_data.st_dev)
		*entry = 'N';

	      else if (*entry == 'Y')
		/* New entry, skip further checks */;

	      /* FIXME: if (S_ISHIDDEN (stat_data.st_mode))?? */

	      else if (OLDER_STAT_TIME (stat_data, m)
		       && (!after_date_option
			   || OLDER_STAT_TIME (stat_data, c)))
		*entry = 'N';
	      else
		*entry = 'Y';
	    }
	}
      free (itr);
    }

  free (name_buffer);
  if (dirp)
    free (dirp);

  return directory->dump ? directory->dump->contents : NULL;
}

const char *
get_directory_contents (char *dir, dev_t device)
{
  return scan_directory (dir, device);
}


static void
obstack_code_rename (struct obstack *stk, char *from, char *to)
{
  char *s;

  s = from[0] == 0 ? from :
                     safer_name_suffix (from, false, absolute_names_option);
  obstack_1grow (stk, 'R');
  obstack_grow (stk, s, strlen (s) + 1);

  s = to[0] == 0 ? to:
                   safer_name_suffix (to, false, absolute_names_option);
  obstack_1grow (stk, 'T');
  obstack_grow (stk, s, strlen (s) + 1);
}

static bool
rename_handler (void *data, void *proc_data)
{
  struct directory *dir = data;
  struct obstack *stk = proc_data;

  if (DIR_IS_RENAMED (dir))
    {
      struct directory *prev, *p;

      /* Detect eventual cycles and clear DIRF_RENAMED flag, so these entries
	 are ignored when hit by this function next time.
	 If the chain forms a cycle, prev points to the entry DIR is renamed
	 from. In this case it still retains DIRF_RENAMED flag, which will be
	 cleared in the `else' branch below */
      for (prev = dir; prev && prev->orig != dir; prev = prev->orig)
	DIR_CLEAR_FLAG (prev, DIRF_RENAMED);

      if (prev == NULL)
	{
	  for (p = dir; p && p->orig; p = p->orig)
	    obstack_code_rename (stk, p->orig->name, p->name);
	}
      else
	{
	  char *temp_name;

	  DIR_CLEAR_FLAG (prev, DIRF_RENAMED);

	  /* Break the cycle by using a temporary name for one of its
	     elements.
	     First, create a temp name stub entry. */
	  temp_name = dir_name (dir->name);
	  obstack_1grow (stk, 'X');
	  obstack_grow (stk, temp_name, strlen (temp_name) + 1);

	  obstack_code_rename (stk, dir->name, "");

	  for (p = dir; p != prev; p = p->orig)
	    obstack_code_rename (stk, p->orig->name, p->name);

	  obstack_code_rename (stk, "", prev->name);
	}
    }
  return true;
}

const char *
append_incremental_renames (const char *dump)
{
  struct obstack stk;
  size_t size;

  if (directory_table == NULL)
    return dump;

  obstack_init (&stk);
  if (dump)
    {
      size = dumpdir_size (dump) - 1;
      obstack_grow (&stk, dump, size);
    }
  else
    size = 0;

  hash_do_for_each (directory_table, rename_handler, &stk);
  if (obstack_object_size (&stk) != size)
    {
      obstack_1grow (&stk, 0);
      dump = obstack_finish (&stk);
    }
  else
    obstack_free (&stk, NULL);
  return dump;
}



static FILE *listed_incremental_stream;

/* Version of incremental format snapshots (directory files) used by this
   tar. Currently it is supposed to be a single decimal number. 0 means
   incremental snapshots as per tar version before 1.15.2.

   The current tar version supports incremental versions from
   0 up to TAR_INCREMENTAL_VERSION, inclusive.
   It is able to create only snapshots of TAR_INCREMENTAL_VERSION */

#define TAR_INCREMENTAL_VERSION 2

/* Read incremental snapshot formats 0 and 1 */
static void
read_incr_db_01 (int version, const char *initbuf)
{
  int n;
  uintmax_t u;
  time_t sec;
  long int nsec;
  char *buf = 0;
  size_t bufsize;
  char *ebuf;
  long lineno = 1;

  if (version == 1)
    {
      if (getline (&buf, &bufsize, listed_incremental_stream) <= 0)
	{
	  read_error (listed_incremental_option);
	  free (buf);
	  return;
	}
      ++lineno;
    }
  else
    {
      buf = strdup (initbuf);
      bufsize = strlen (buf) + 1;
    }

  sec = TYPE_MINIMUM (time_t);
  nsec = -1;
  errno = 0;
  u = strtoumax (buf, &ebuf, 10);
  if (!errno && TYPE_MAXIMUM (time_t) < u)
    errno = ERANGE;
  if (errno || buf == ebuf)
    ERROR ((0, errno, "%s:%ld: %s",
	    quotearg_colon (listed_incremental_option),
	    lineno,
	    _("Invalid time stamp")));
  else
    {
      sec = u;

      if (version == 1 && *ebuf)
	{
	  char const *buf_ns = ebuf + 1;
	  errno = 0;
	  u = strtoumax (buf_ns, &ebuf, 10);
	  if (!errno && BILLION <= u)
	    errno = ERANGE;
	  if (errno || buf_ns == ebuf)
	    {
	      ERROR ((0, errno, "%s:%ld: %s",
		      quotearg_colon (listed_incremental_option),
		      lineno,
		      _("Invalid time stamp")));
	      sec = TYPE_MINIMUM (time_t);
	    }
	  else
	    nsec = u;
	}
      else
	{
	  /* pre-1 incremental format does not contain nanoseconds */
	  nsec = 0;
	}
    }
  newer_mtime_option.tv_sec = sec;
  newer_mtime_option.tv_nsec = nsec;


  while (0 < (n = getline (&buf, &bufsize, listed_incremental_stream)))
    {
      dev_t dev;
      ino_t ino;
      bool nfs = buf[0] == '+';
      char *strp = buf + nfs;
      struct timespec mtime;

      lineno++;

      if (buf[n - 1] == '\n')
	buf[n - 1] = '\0';

      if (version == 1)
	{
	  errno = 0;
	  u = strtoumax (strp, &ebuf, 10);
	  if (!errno && TYPE_MAXIMUM (time_t) < u)
	    errno = ERANGE;
	  if (errno || strp == ebuf || *ebuf != ' ')
	    {
	      ERROR ((0, errno, "%s:%ld: %s",
		      quotearg_colon (listed_incremental_option), lineno,
		      _("Invalid modification time (seconds)")));
	      sec = (time_t) -1;
	    }
	  else
	    sec = u;
	  strp = ebuf;

	  errno = 0;
	  u = strtoumax (strp, &ebuf, 10);
	  if (!errno && BILLION <= u)
	    errno = ERANGE;
	  if (errno || strp == ebuf || *ebuf != ' ')
	    {
	      ERROR ((0, errno, "%s:%ld: %s",
		      quotearg_colon (listed_incremental_option), lineno,
		      _("Invalid modification time (nanoseconds)")));
	      nsec = -1;
	    }
	  else
	    nsec = u;
	  mtime.tv_sec = sec;
	  mtime.tv_nsec = nsec;
	  strp = ebuf;
	}
      else
	memset (&mtime, 0, sizeof mtime);

      errno = 0;
      u = strtoumax (strp, &ebuf, 10);
      if (!errno && TYPE_MAXIMUM (dev_t) < u)
	errno = ERANGE;
      if (errno || strp == ebuf || *ebuf != ' ')
	{
	  ERROR ((0, errno, "%s:%ld: %s",
		  quotearg_colon (listed_incremental_option), lineno,
		  _("Invalid device number")));
	  dev = (dev_t) -1;
	}
      else
	dev = u;
      strp = ebuf;

      errno = 0;
      u = strtoumax (strp, &ebuf, 10);
      if (!errno && TYPE_MAXIMUM (ino_t) < u)
	errno = ERANGE;
      if (errno || strp == ebuf || *ebuf != ' ')
	{
	  ERROR ((0, errno, "%s:%ld: %s",
		  quotearg_colon (listed_incremental_option), lineno,
		  _("Invalid inode number")));
	  ino = (ino_t) -1;
	}
      else
	ino = u;
      strp = ebuf;

      strp++;
      unquote_string (strp);
      note_directory (strp, mtime, dev, ino, nfs, false, NULL);
    }
  free (buf);
}

/* Read a nul-terminated string from FP and store it in STK.
   Store the number of bytes read (including nul terminator) in PCOUNT.

   Return the last character read or EOF on end of file. */
static int
read_obstack (FILE *fp, struct obstack *stk, size_t *pcount)
{
  int c;
  size_t i;

  for (i = 0, c = getc (fp); c != EOF && c != 0; c = getc (fp), i++)
    obstack_1grow (stk, c);
  obstack_1grow (stk, 0);

  *pcount = i;
  return c;
}

/* Read from file FP a nul-terminated string and convert it to
   intmax_t.  Return the resulting value in PVAL.  Assume '-' has
   already been read.

   Throw a fatal error if the string cannot be converted or if the
   converted value is less than MIN_VAL.  */

static void
read_negative_num (FILE *fp, intmax_t min_val, intmax_t *pval)
{
  int c;
  size_t i;
  char buf[INT_BUFSIZE_BOUND (intmax_t)];
  char *ep;
  buf[0] = '-';

  for (i = 1; ISDIGIT (c = getc (fp)); i++)
    {
      if (i == sizeof buf - 1)
	FATAL_ERROR ((0, 0, _("Field too long while reading snapshot file")));
      buf[i] = c;
    }

  if (c < 0)
    {
      if (ferror (fp))
	FATAL_ERROR ((0, errno, _("Read error in snapshot file")));
      else
	FATAL_ERROR ((0, 0, _("Unexpected EOF in snapshot file")));
    }

  buf[i] = 0;
  errno = 0;
  *pval = strtoimax (buf, &ep, 10);
  if (c || errno || *pval < min_val)
    FATAL_ERROR ((0, errno, _("Unexpected field value in snapshot file")));
}

/* Read from file FP a nul-terminated string and convert it to
   uintmax_t.  Return the resulting value in PVAL.  Assume C has
   already been read.

   Throw a fatal error if the string cannot be converted or if the
   converted value exceeds MAX_VAL.

   Return the last character read or EOF on end of file. */

static int
read_unsigned_num (int c, FILE *fp, uintmax_t max_val, uintmax_t *pval)
{
  size_t i;
  char buf[UINTMAX_STRSIZE_BOUND], *ep;

  for (i = 0; ISDIGIT (c); i++)
    {
      if (i == sizeof buf - 1)
	FATAL_ERROR ((0, 0, _("Field too long while reading snapshot file")));
      buf[i] = c;
      c = getc (fp);
    }

  if (c < 0)
    {
      if (ferror (fp))
	FATAL_ERROR ((0, errno, _("Read error in snapshot file")));
      else if (i == 0)
	return c;
      else
	FATAL_ERROR ((0, 0, _("Unexpected EOF in snapshot file")));
    }

  buf[i] = 0;
  errno = 0;
  *pval = strtoumax (buf, &ep, 10);
  if (c || errno || max_val < *pval)
    FATAL_ERROR ((0, errno, _("Unexpected field value in snapshot file")));
  return c;
}

/* Read from file FP a nul-terminated string and convert it to
   uintmax_t.  Return the resulting value in PVAL.

   Throw a fatal error if the string cannot be converted or if the
   converted value exceeds MAX_VAL.

   Return the last character read or EOF on end of file. */

static int
read_num (FILE *fp, uintmax_t max_val, uintmax_t *pval)
{
  return read_unsigned_num (getc (fp), fp, max_val, pval);
}

/* Read from FP two NUL-terminated strings representing a struct
   timespec.  Return the resulting value in PVAL.

   Throw a fatal error if the string cannot be converted.  */

static void
read_timespec (FILE *fp, struct timespec *pval)
{
  int c = getc (fp);
  intmax_t i;
  uintmax_t u;

  if (c == '-')
    {
      read_negative_num (fp, TYPE_MINIMUM (time_t), &i);
      c = 0;
      pval->tv_sec = i;
    }
  else
    {
      c = read_unsigned_num (c, fp, TYPE_MAXIMUM (time_t), &u);