xheader.c

gnu tar 源码包。 tar 软件是 Unix 系统下的一个打包软件

      return false;
    }

  if (len_max < len)
    {
      int len_len = len_lim - p;
      ERROR ((0, 0, _("Extended header length %*s is out of range"),
	      len_len, p));
      return false;
    }

  nextp = start + len;

  for (p = len_lim; *p == ' ' || *p == '\t'; p++)
    continue;
  if (p == len_lim)
    {
      ERROR ((0, 0,
	      _("Malformed extended header: missing blank after length")));
      return false;
    }

  keyword = p;
  p = strchr (p, '=');
  if (! (p && p < nextp))
    {
      ERROR ((0, 0, _("Malformed extended header: missing equal sign")));
      return false;
    }

  if (nextp[-1] != '\n')
    {
      ERROR ((0, 0, _("Malformed extended header: missing newline")));
      return false;
    }

  *p = nextp[-1] = '\0';
  handler (data, keyword, p + 1, nextp - p - 2); /* '=' + trailing '\n' */
  *p = '=';
  nextp[-1] = '\n';
  *ptr = nextp;
  return true;
}

static void
run_override_list (struct keyword_list *kp, struct tar_stat_info *st)
{
  for (; kp; kp = kp->next)
    {
      struct xhdr_tab const *t = locate_handler (kp->pattern);
      if (t)
	t->decoder (st, t->keyword, kp->value, strlen (kp->value));
    }
}

static void
decx (void *data, char const *keyword, char const *value, size_t size)
{
  struct xhdr_tab const *t;
  struct tar_stat_info *st = data;

  if (xheader_keyword_deleted_p (keyword)
      || xheader_keyword_override_p (keyword))
    return;

  t = locate_handler (keyword);
  if (t)
    t->decoder (st, keyword, value, size);
  else
    WARN((0, 0, _("Ignoring unknown extended header keyword `%s'"),
	 keyword));
}

void
xheader_decode (struct tar_stat_info *st)
{
  run_override_list (keyword_global_override_list, st);
  run_override_list (global_header_override_list, st);

  if (st->xhdr.size)
    {
      char *p = st->xhdr.buffer + BLOCKSIZE;
      while (decode_record (&st->xhdr, &p, decx, st))
	continue;
    }
  run_override_list (keyword_override_list, st);
}

static void
decg (void *data, char const *keyword, char const *value,
      size_t size __attribute__((unused)))
{
  struct keyword_list **kwl = data;
  xheader_list_append (kwl, keyword, value);
}

void
xheader_decode_global (struct xheader *xhdr)
{
  if (xhdr->size)
    {
      char *p = xhdr->buffer + BLOCKSIZE;

      xheader_list_destroy (&global_header_override_list);
      while (decode_record (xhdr, &p, decg, &global_header_override_list))
	continue;
    }
}

void
xheader_init (struct xheader *xhdr)
{
  if (!xhdr->stk)
    {
      xhdr->stk = xmalloc (sizeof *xhdr->stk);
      obstack_init (xhdr->stk);
    }
}

void
xheader_store (char const *keyword, struct tar_stat_info *st,
	       void const *data)
{
  struct xhdr_tab const *t;

  if (st->xhdr.buffer)
    return;
  t = locate_handler (keyword);
  if (!t || !t->coder)
    return;
  if (xheader_keyword_deleted_p (keyword)
      || xheader_keyword_override_p (keyword))
    return;
  xheader_init (&st->xhdr);
  t->coder (st, keyword, &st->xhdr, data);
}

void
xheader_read (struct xheader *xhdr, union block *p, size_t size)
{
  size_t j = 0;

  xheader_init (xhdr);
  size += BLOCKSIZE;
  xhdr->size = size;
  xhdr->buffer = xmalloc (size + 1);
  xhdr->buffer[size] = '\0';

  do
    {
      size_t len = size;

      if (len > BLOCKSIZE)
	len = BLOCKSIZE;

      memcpy (&xhdr->buffer[j], p->buffer, len);
      set_next_block_after (p);

      p = find_next_block ();

      j += len;
      size -= len;
    }
  while (size > 0);
}

static void
xheader_print_n (struct xheader *xhdr, char const *keyword,
		 char const *value, size_t vsize)
{
  size_t len = strlen (keyword) + vsize + 3; /* ' ' + '=' + '\n' */
  size_t p;
  size_t n = 0;
  char nbuf[UINTMAX_STRSIZE_BOUND];
  char const *np;

  do
    {
      p = n;
      np = umaxtostr (len + p, nbuf);
      n = nbuf + sizeof nbuf - 1 - np;
    }
  while (n != p);

  x_obstack_grow (xhdr, np, n);
  x_obstack_1grow (xhdr, ' ');
  x_obstack_grow (xhdr, keyword, strlen (keyword));
  x_obstack_1grow (xhdr, '=');
  x_obstack_grow (xhdr, value, vsize);
  x_obstack_1grow (xhdr, '\n');
}

static void
xheader_print (struct xheader *xhdr, char const *keyword, char const *value)
{
  xheader_print_n (xhdr, keyword, value, strlen (value));
}

void
xheader_finish (struct xheader *xhdr)
{
  struct keyword_list *kp;

  for (kp = keyword_override_list; kp; kp = kp->next)
    code_string (kp->value, kp->pattern, xhdr);

  xhdr->buffer = obstack_finish (xhdr->stk);
}

void
xheader_destroy (struct xheader *xhdr)
{
  if (xhdr->stk)
    {
      obstack_free (xhdr->stk, NULL);
      free (xhdr->stk);
      xhdr->stk = NULL;
    }
  else
    free (xhdr->buffer);
  xhdr->buffer = 0;
  xhdr->size = 0;
}


/* Buildable strings */

void
xheader_string_begin (struct xheader *xhdr)
{
  xhdr->string_length = 0;
}

void
xheader_string_add (struct xheader *xhdr, char const *s)
{
  if (xhdr->buffer)
    return;
  xheader_init (xhdr);
  xhdr->string_length += strlen (s);
  x_obstack_grow (xhdr, s, strlen (s));
}

bool
xheader_string_end (struct xheader *xhdr, char const *keyword)
{
  uintmax_t len;
  uintmax_t p;
  uintmax_t n = 0;
  size_t size;
  char nbuf[UINTMAX_STRSIZE_BOUND];
  char const *np;
  char *cp;

  if (xhdr->buffer)
    return false;
  xheader_init (xhdr);

  len = strlen (keyword) + xhdr->string_length + 3; /* ' ' + '=' + '\n' */

  do
    {
      p = n;
      np = umaxtostr (len + p, nbuf);
      n = nbuf + sizeof nbuf - 1 - np;
    }
  while (n != p);

  p = strlen (keyword) + n + 2;
  size = p;
  if (size != p)
    {
      ERROR ((0, 0,
        _("Generated keyword/value pair is too long (keyword=%s, length=%s)"),
	      keyword, nbuf));
      obstack_free (xhdr->stk, obstack_finish (xhdr->stk));
      return false;
    }
  x_obstack_blank (xhdr, p);
  x_obstack_1grow (xhdr, '\n');
  cp = obstack_next_free (xhdr->stk) - xhdr->string_length - p - 1;
  memmove (cp + p, cp, xhdr->string_length);
  cp = stpcpy (cp, np);
  *cp++ = ' ';
  cp = stpcpy (cp, keyword);
  *cp++ = '=';
  return true;
}


/* Implementations */

static void
out_of_range_header (char const *keyword, char const *value,
		     uintmax_t minus_minval, uintmax_t maxval)
{
  char minval_buf[UINTMAX_STRSIZE_BOUND + 1];
  char maxval_buf[UINTMAX_STRSIZE_BOUND];
  char *minval_string = umaxtostr (minus_minval, minval_buf + 1);
  char *maxval_string = umaxtostr (maxval, maxval_buf);
  if (minus_minval)
    *--minval_string = '-';

  /* TRANSLATORS: The first %s is the pax extended header keyword
     (atime, gid, etc.).  */
  ERROR ((0, 0, _("Extended header %s=%s is out of range %s..%s"),
	  keyword, value, minval_string, maxval_string));
}

static void
code_string (char const *string, char const *keyword, struct xheader *xhdr)
{
  char *outstr;
  if (!utf8_convert (true, string, &outstr))
    {
      /* FIXME: report error */
      outstr = xstrdup (string);
    }
  xheader_print (xhdr, keyword, outstr);
  free (outstr);
}

static void
decode_string (char **string, char const *arg)
{
  if (*string)
    {
      free (*string);
      *string = NULL;
    }
  if (!utf8_convert (false, arg, string))
    {
      /* FIXME: report error and act accordingly to --pax invalid=UTF-8 */
      assign_string (string, arg);
    }
}

static void
code_time (struct timespec t, char const *keyword, struct xheader *xhdr)
{
  char buf[TIMESPEC_STRSIZE_BOUND];
  xheader_print (xhdr, keyword, code_timespec (t, buf));
}

enum decode_time_status
  {
    decode_time_success,
    decode_time_range,
    decode_time_bad_header
  };

static enum decode_time_status
_decode_time (struct timespec *ts, char const *arg, char const *keyword)
{
  time_t s;
  unsigned long int ns = 0;
  char *p;
  char *arg_lim;
  bool negative = *arg == '-';

  errno = 0;

  if (ISDIGIT (arg[negative]))
    {
      if (negative)
	{
	  intmax_t i = strtoimax (arg, &arg_lim, 10);
	  if (TYPE_SIGNED (time_t) ? i < TYPE_MINIMUM (time_t) : i < 0)
	    return decode_time_range;
	  s = i;
	}
      else
	{
	  uintmax_t i = strtoumax (arg, &arg_lim, 10);
	  if (TYPE_MAXIMUM (time_t) < i)
	    return decode_time_range;
	  s = i;
	}

      p = arg_lim;

      if (errno == ERANGE)
	return decode_time_range;

      if (*p == '.')
	{
	  int digits = 0;
	  bool trailing_nonzero = false;

	  while (ISDIGIT (*++p))
	    if (digits < LOG10_BILLION)
	      {
		ns = 10 * ns + (*p - '0');
		digits++;
	      }
	    else
	      trailing_nonzero |= *p != '0';

	  while (digits++ < LOG10_BILLION)
	    ns *= 10;

	  if (negative)
	    {
	      /* Convert "-1.10000000000001" to s == -2, ns == 89999999.
		 I.e., truncate time stamps towards minus infinity while
		 converting them to internal form.  */
	      ns += trailing_nonzero;
	      if (ns != 0)
		{
		  if (s == TYPE_MINIMUM (time_t))
		    return decode_time_range;
		  s--;
		  ns = BILLION - ns;
		}
	    }
	}

      if (! *p)
	{
	  ts->tv_sec = s;
	  ts->tv_nsec = ns;
	  return decode_time_success;
	}
    }

  return decode_time_bad_header;
}

static bool
decode_time (struct timespec *ts, char const *arg, char const *keyword)
{
  switch (_decode_time (ts, arg, keyword))
    {
    case decode_time_success:
      return true;
    case decode_time_bad_header:
      ERROR ((0, 0, _("Malformed extended header: invalid %s=%s"),
	      keyword, arg));
      return false;
    case decode_time_range:
      out_of_range_header (keyword, arg, - (uintmax_t) TYPE_MINIMUM (time_t),
			   TYPE_MAXIMUM (time_t));
      return false;
    }
  return true;
}



static void
code_num (uintmax_t value, char const *keyword, struct xheader *xhdr)
{
  char sbuf[UINTMAX_STRSIZE_BOUND];
  xheader_print (xhdr, keyword, umaxtostr (value, sbuf));
}

static bool
decode_num (uintmax_t *num, char const *arg, uintmax_t maxval,
	    char const *keyword)
{
  uintmax_t u;
  char *arg_lim;

  if (! (ISDIGIT (*arg)
	 && (errno = 0, u = strtoumax (arg, &arg_lim, 10), !*arg_lim)))
    {
      ERROR ((0, 0, _("Malformed extended header: invalid %s=%s"),
	      keyword, arg));
      return false;
    }

  if (! (u <= maxval && errno != ERANGE))
    {
      out_of_range_header (keyword, arg, 0, maxval);
      return false;
    }

  *num = u;
  return true;
}

static void
dummy_coder (struct tar_stat_info const *st __attribute__ ((unused)),
	     char const *keyword __attribute__ ((unused)),
	     struct xheader *xhdr __attribute__ ((unused)),
	     void const *data __attribute__ ((unused)))
{
}

static void
dummy_decoder (struct tar_stat_info *st __attribute__ ((unused)),
	       char const *keyword __attribute__ ((unused)),
	       char const *arg __attribute__ ((unused)),
	       size_t size __attribute__((unused)))
{
}

static void
atime_coder (struct tar_stat_info const *st, char const *keyword,
	     struct xheader *xhdr, void const *data __attribute__ ((unused)))
{
  code_time (st->atime, keyword, xhdr);
}

static void
atime_decoder (struct tar_stat_info *st,