elf/dl-dst.h

   1 /* Handling of dynamic sring tokens.
   2    Copyright (C) 1999, 2001 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 Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 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, '$');                                    \
  26                                                                               \
  27     if (__builtin_expect (__sf != NULL, 0))                                   \
  28       __cnt = _dl_dst_count (__sf, is_path);                                  \
  29                                                                               \
  30     __cnt; })
  31
  32 /* Prototype for used function.  */
  33 extern size_t _dl_dst_count (const char *name, int is_path);
  34
  35
  36 /* Guess from the number of DSTs the length of the result string.  */
  37 #define DL_DST_REQUIRED(l, name, len, cnt) \
  38   ({                                                                          \
  39     size_t origin_len;                                                        \
  40     size_t __len = (len);                                                     \
  41                                                                               \
  42     /* Now we make a guess how many extra characters on top of the length     \
  43        of S we need to represent the result.  We know that we have CNT        \
  44        replacements.  Each at most can use                                    \
  45          MAX (strlen (ORIGIN), strlen (_dl_platform))                         \
  46        minus 7 (which is the length of "$ORIGIN").                            \
  47                                                                               \
  48        First get the origin string if it is not available yet.  This can      \
  49        only happen for the map of the executable.  */                         \
  50     if ((l)->l_origin == NULL)                                                \
  51       {                                                                       \
  52         assert ((l)->l_name[0] == '\0');                                      \
  53         (l)->l_origin = _dl_get_origin ();                                    \
  54         origin_len = ((l)->l_origin && (l)->l_origin != (char *) -1           \
  55                       ? strlen ((l)->l_origin) : 0);                          \
  56       }                                                                       \
  57     else                                                                      \
  58       origin_len = (l)->l_origin == (char *) -1 ? 0 : strlen ((l)->l_origin); \
  59                                                                               \
  60     __len + cnt * (MAX (origin_len, _dl_platformlen) - 7); })
  61
  62 /* Find origin of the executable.  */
  63 extern const char *_dl_get_origin (void);
  64
  65
  66 /* Perform the DST substitution.  */
  67 #define DL_DST_SUBSTITUTE(l, name, res, is_path) \
  68   _dl_dst_substitute (l, name, res, is_path)
  69
  70 /* Prototype for used function.  */
  71 extern char *_dl_dst_substitute (struct link_map *l, const char *name,
  72                                  char *result, int is_path);