elf/dl-dst.h

   1 /* Handling of dynamic sring tokens.
   2    Copyright (C) 1999,2001-2004,2006,2007,2011 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 #include "trusted-dirs.h"
  21
  22 /* Determine the number of DST elements in the name.  Only if IS_PATH is
  23    nonzero paths are recognized (i.e., multiple, ':' separated filenames).  */
  24 #define DL_DST_COUNT(name, is_path) \
  25   ({                                                                          \
  26     size_t __cnt = 0;                                                         \
  27     const char *__sf = strchr (name, '$');                                    \
  28                                                                               \
  29     if (__builtin_expect (__sf != NULL, 0))                                   \
  30       __cnt = _dl_dst_count (__sf, is_path);                          \
  31                                                                               \
  32     __cnt; })
  33
  34
  35 #ifdef SHARED
  36 # define IS_RTLD(l) (l) == &GL(dl_rtld_map)
  37 #else
  38 # define IS_RTLD(l) 0
  39 #endif
  40 /* Guess from the number of DSTs the length of the result string.  */
  41 #define DL_DST_REQUIRED(l, name, len, cnt) \
  42   ({                                                                          \
  43     size_t __len = (len);                                                     \
  44     size_t __cnt = (cnt);                                                     \
  45                                                                               \
  46     if (__cnt > 0)                                                            \
  47       {                                                                       \
  48         size_t dst_len;                                                       \
  49         /* Now we make a guess how many extra characters on top of the        \
  50            length of S we need to represent the result.  We know that         \
  51            we have CNT replacements.  Each at most can use                    \
  52              MAX (MAX (strlen (ORIGIN), strlen (_dl_platform)),               \
  53                   strlen (DL_DST_LIB))                                        \
  54            minus 4 (which is the length of "$LIB").                           \
  55                                                                               \
  56            First get the origin string if it is not available yet.            \
  57            This can only happen for the map of the executable or, when        \
  58            auditing, in ld.so.  */                                            \
  59         DL_DST_REQ_STATIC (l)                                                 \
  60         if ((l)->l_origin == NULL)                                            \
  61           {                                                                   \
  62             assert ((l)->l_name[0] == '\0' || IS_RTLD (l));                   \
  63             (l)->l_origin = _dl_get_origin ();                                \
  64             dst_len = ((l)->l_origin && (l)->l_origin != (char *) -1          \
  65                           ? strlen ((l)->l_origin) : 0);                      \
  66           }                                                                   \
  67         else                                                                  \
  68           dst_len = (l)->l_origin == (char *) -1                              \
  69             ? 0 : strlen ((l)->l_origin);                                     \
  70         dst_len = MAX (MAX (dst_len, GLRO(dl_platformlen)),                   \
  71                        strlen (DL_DST_LIB));                                  \
  72         if (dst_len > 4)                                                      \
  73           __len += __cnt * (dst_len - 4);                                     \
  74       }                                                                       \
  75                                                                               \
  76     __len; })
  77
  78 #ifdef SHARED
  79 # define DL_DST_REQ_STATIC(l) /* nothing */
  80 #else
  81 # define DL_DST_REQ_STATIC(l) \
  82   if ((l) == NULL)                                                            \
  83     {                                                                         \
  84       const char *origin = _dl_get_origin ();                                 \
  85       dst_len = (origin && origin != (char *) -1 ? strlen (origin) : 0);      \
  86     }                                                                         \
  87   else
  88 #endif