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 /* Determine the number of DST elements in the name.  Only if IS_PATH is
  22    nonzero paths are recognized (i.e., multiple, ':' separated filenames).  */
  23 #define DL_DST_COUNT(name, is_path) \
  24   ({                                                                          \
  25     size_t __cnt = 0;                                                         \
  26     const char *__sf = strchr (name, '$');                                    \
  27                                                                               \
  28     if (__builtin_expect (__sf != NULL, 0))                                   \
  29       __cnt = _dl_dst_count (__sf, is_path);                          \
  30                                                                               \
  31     __cnt; })
  32 #ifndef IS_IN_rtld
  33 # define _dl_dst_count GLRO(dl_dst_count)
  34 #endif
  35
  36
  37 /* Guess from the number of DSTs the length of the result string.  */
  38 #define DL_DST_REQUIRED(l, name, len, cnt) \
  39   ({                                                                          \
  40     size_t __len = (len);                                                     \
  41     size_t __cnt = (cnt);                                                     \
  42                                                                               \
  43     if (__cnt > 0)                                                            \
  44       {                                                                       \
  45         size_t origin_len;                                                    \
  46         /* Now we make a guess how many extra characters on top of the        \
  47            length of S we need to represent the result.  We know that         \
  48            we have CNT replacements.  Each at most can use                    \
  49              MAX (strlen (ORIGIN), strlen (_dl_platform))                     \
  50            minus 7 (which is the length of "$ORIGIN").                        \
  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             origin_len = ((l)->l_origin && (l)->l_origin != (char *) -1       \
  60                           ? strlen ((l)->l_origin) : 0);                      \
  61           }                                                                   \
  62         else                                                                  \
  63           origin_len = (l)->l_origin == (char *) -1                           \
  64             ? 0 : strlen ((l)->l_origin);                                     \
  65                                                                               \
  66         __len += __cnt * (MAX (origin_len, GLRO(dl_platformlen)) - 7);        \
  67       }                                                                       \
  68                                                                               \
  69     __len; })
  70
  71 #ifdef SHARED
  72 # define DL_DST_REQ_STATIC(l) /* nothing */
  73 #else
  74 # define DL_DST_REQ_STATIC(l) \
  75   if ((l) == NULL)                                                            \
  76     {                                                                         \
  77       const char *origin = _dl_get_origin ();                                 \
  78       origin_len = (origin && origin != (char *) -1 ? strlen (origin) : 0);   \
  79     }                                                                         \
  80   else
  81 #endif
  82
  83 #ifndef IS_IN_rtld
  84 # define _dl_get_origin GLRO(dl_get_origin)
  85 # define _dl_dst_substitute GLRO(dl_dst_substitute)
  86 #endif