elf/dl-dst.h

   1 /* Handling of dynamic sring tokens.
   2    Copyright (C) 1999,2001,2002,2003,2004,2006,2007
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include "trusted-dirs.h"
  22
  23 /* Determine the number of DST elements in the name.  Only if IS_PATH is
  24    nonzero paths are recognized (i.e., multiple, ':' separated filenames).  */
  25 #define DL_DST_COUNT(name, is_path) \
  26   ({                                                                          \
  27     size_t __cnt = 0;                                                         \
  28     const char *__sf = strchr (name, '$');                                    \
  29                                                                               \
  30     if (__builtin_expect (__sf != NULL, 0))                                   \
  31       __cnt = _dl_dst_count (__sf, is_path);                          \
  32                                                                               \
  33     __cnt; })
  34
  35
  36 /* Guess from the number of DSTs the length of the result string.  */
  37 #define DL_DST_REQUIRED(l, name, len, cnt) \
  38   ({                                                                          \
  39     size_t __len = (len);                                                     \
  40     size_t __cnt = (cnt);                                                     \
  41                                                                               \
  42     if (__cnt > 0)                                                            \
  43       {                                                                       \
  44         size_t dst_len;                                                       \
  45         /* Now we make a guess how many extra characters on top of the        \
  46            length of S we need to represent the result.  We know that         \
  47            we have CNT replacements.  Each at most can use                    \
  48              MAX (MAX (strlen (ORIGIN), strlen (_dl_platform)),               \
  49                   strlen (DL_DST_LIB))                                        \
  50            minus 4 (which is the length of "$LIB").                           \
  51                                                                               \
  52            First get the origin string if it is not available yet.            \
  53            This can only happen for the map of the executable.  */            \
  54         DL_DST_REQ_STATIC (l)                                                 \
  55         if ((l)->l_origin == NULL)                                            \
  56           {                                                                   \
  57             assert ((l)->l_name[0] == '\0');                                  \
  58             (l)->l_origin = _dl_get_origin ();                                \
  59             dst_len = ((l)->l_origin && (l)->l_origin != (char *) -1          \
  60                           ? strlen ((l)->l_origin) : 0);                      \
  61           }                                                                   \
  62         else                                                                  \
  63           dst_len = (l)->l_origin == (char *) -1                              \
  64             ? 0 : strlen ((l)->l_origin);                                     \
  65         dst_len = MAX (MAX (dst_len, GLRO(dl_platformlen)),                   \
  66                        strlen (DL_DST_LIB));                                  \
  67         if (dst_len > 4)                                                      \
  68           __len += __cnt * (dst_len - 4);                                     \
  69       }                                                                       \
  70                                                                               \
  71     __len; })
  72
  73 #ifdef SHARED
  74 # define DL_DST_REQ_STATIC(l) /* nothing */
  75 #else
  76 # define DL_DST_REQ_STATIC(l) \
  77   if ((l) == NULL)                                                            \
  78     {                                                                         \
  79       const char *origin = _dl_get_origin ();                                 \
  80       dst_len = (origin && origin != (char *) -1 ? strlen (origin) : 0);      \
  81     }                                                                         \
  82   else
  83 #endif