elf/dl-dst.h

   1 /* Handling of dynamic sring tokens.
   2    Copyright (C) 1999,2001,2002,2003,2004,2006 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 /* Determine the number of DST elements in the name.  Only if IS_PATH is
  21    nonzero paths are recognized (i.e., multiple, ':' separated filenames).  */
  22 #define DL_DST_COUNT(name, is_path) \
  23   ({                                                                          \
  24     size_t __cnt = 0;                                                         \
  25     const char *__sf = strchr (name, '$');                                    \
  26                                                                               \
  27     if (__builtin_expect (__sf != NULL, 0))                                   \
  28       __cnt = _dl_dst_count (__sf, is_path);                          \
  29                                                                               \
  30     __cnt; })
  31 #ifndef IS_IN_rtld
  32 # define _dl_dst_count GLRO(dl_dst_count)
  33 #endif
  34
  35
  36 /* Guess from the number of DSTs the length of the result string.  */
  37 #define DL_DST_REQUIRED(l, name, len, cnt) \
  38   ({                                                                          \
  39     size_t __len = (len);                                                     \
  40     size_t __cnt = (cnt);                                                     \
  41                                                                               \
  42     if (__cnt > 0)                                                            \
  43       {                                                                       \
  44         size_t origin_len;                                                    \
  45         /* Now we make a guess how many extra characters on top of the        \
  46            length of S we need to represent the result.  We know that         \
  47            we have CNT replacements.  Each at most can use                    \
  48              MAX (strlen (ORIGIN), strlen (_dl_platform))                     \
  49            minus 7 (which is the length of "$ORIGIN").                        \
  50                                                                               \
  51            First get the origin string if it is not available yet.            \
  52            This can only happen for the map of the executable.  */            \
  53         DL_DST_REQ_STATIC                                                     \
  54         if ((l)->l_origin == NULL)                                            \
  55           {                                                                   \
  56             assert ((l)->l_name[0] == '\0');                                  \
  57             (l)->l_origin = _dl_get_origin ();                                \
  58             origin_len = ((l)->l_origin && (l)->l_origin != (char *) -1       \
  59                           ? strlen ((l)->l_origin) : 0);                      \
  60           }                                                                   \
  61         else                                                                  \
  62           origin_len = (l)->l_origin == (char *) -1                           \
  63             ? 0 : strlen ((l)->l_origin);                                     \
  64                                                                               \
  65         __len += __cnt * (MAX (origin_len, GLRO(dl_platformlen)) - 7);        \
  66       }                                                                       \
  67                                                                               \
  68     __len; })
  69
  70 #ifdef SHARED
  71 # define DL_DST_REQ_STATIC /* nothing */
  72 #else
  73 # define DL_DST_REQ_STATIC \
  74   if ((l) == NULL)                                                            \
  75     {                                                                         \
  76       const char *origin = _dl_get_origin ();                                 \
  77       origin_len = (origin && origin != (char *) -1 ? strlen (origin) : 0);   \
  78     }                                                                         \
  79   else
  80 #endif
  81
  82 #ifndef IS_IN_rtld
  83 # define _dl_get_origin GLRO(dl_get_origin)
  84 # define _dl_dst_substitute GLRO(dl_dst_substitute)
  85 #endif