1  /* Handling of dynamic string tokens.
       2     Copyright (C) 1999-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include "trusted-dirs.h"
      20  
      21  #ifdef SHARED
      22  # define IS_RTLD(l) (l) == &GL(dl_rtld_map)
      23  #else
      24  # define IS_RTLD(l) 0
      25  #endif
      26  /* Guess from the number of DSTs the length of the result string.  */
      27  #define DL_DST_REQUIRED(l, name, len, cnt) \
      28    ({									      \
      29      size_t __len = (len);						      \
      30      size_t __cnt = (cnt);						      \
      31  									      \
      32      if (__cnt > 0)							      \
      33        {									      \
      34  	size_t dst_len;							      \
      35  	/* Now we make a guess how many extra characters on top of the	      \
      36  	   length of S we need to represent the result.  We know that	      \
      37  	   we have CNT replacements.  Each at most can use		      \
      38  	     MAX (MAX (strlen (ORIGIN), strlen (_dl_platform)),		      \
      39  		  strlen (DL_DST_LIB))					      \
      40  	   minus 4 (which is the length of "$LIB").			      \
      41  									      \
      42  	   First get the origin string if it is not available yet.	      \
      43  	   This can only happen for the map of the executable or, when	      \
      44  	   auditing, in ld.so.  */					      \
      45  	if ((l)->l_origin == NULL)					      \
      46  	  {								      \
      47  	    assert ((l)->l_name[0] == '\0' || IS_RTLD (l));		      \
      48  	    (l)->l_origin = _dl_get_origin ();				      \
      49  	    dst_len = ((l)->l_origin && (l)->l_origin != (char *) -1	      \
      50  			  ? strlen ((l)->l_origin) : 0);		      \
      51  	  }								      \
      52  	else								      \
      53  	  dst_len = (l)->l_origin == (char *) -1			      \
      54  	    ? 0 : strlen ((l)->l_origin);				      \
      55  	dst_len = MAX (MAX (dst_len, GLRO(dl_platformlen)),		      \
      56  		       strlen (DL_DST_LIB));				      \
      57  	if (dst_len > 4)						      \
      58  	  __len += __cnt * (dst_len - 4);				      \
      59        }									      \
      60  									      \
      61      __len; })