elf/dl-support.c

   1 /* Support for dynamic linking code in static libc.
   2 Copyright (C) 1996 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
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #include <assert.h>
  21 #include <fcntl.h>
  22 #include <unistd.h>
  23 #include <sys/mman.h>
  24 #include <sys/stat.h>
  25
  26 /* This file defines some things that for the dynamic linker are defined in
  27    rtld.c and dl-sysdep.c in ways appropriate to bootstrap dynamic linking.  */
  28
  29 extern char *__progname;
  30 char **_dl_argv = &__progname;  /* This is checked for some error messages.  */
  31
  32 /* This defines the default search path for libraries.
  33    For the dynamic linker it is set by -rpath when linking.  */
  34 const char *_dl_rpath = DEFAULT_RPATH;
  35 \f
  36 /* This is the only dl-sysdep.c function that is actually needed at run-time
  37    by _dl_map_object.  */
  38
  39 int
  40 _dl_sysdep_open_zero_fill (void)
  41 {
  42   return __open ("/dev/zero", O_RDONLY);
  43 }
  44
  45 /* This should never be called.  */
  46 void
  47 _dl_sysdep_fatal (void)
  48 {
  49   assert (! "_dl_sysdep_fatal called");
  50 }
  51
  52 /* Read the whole contents of FILE into new mmap'd space with given
  53    protections.  *SIZEP gets the size of the file.  */
  54
  55 void *
  56 _dl_sysdep_read_whole_file (const char *file, size_t *sizep, int prot)
  57 {
  58   void *result;
  59   struct stat st;
  60   int fd = __open (file, O_RDONLY);
  61   if (fd < 0)
  62     return NULL;
  63   if (__fstat (fd, &st) < 0)
  64     result = NULL;
  65   else
  66     {
  67       /* Map a copy of the file contents.  */
  68       result = __mmap (0, st.st_size, prot,
  69 #ifdef MAP_COPY
  70                        MAP_COPY
  71 #else
  72                        MAP_PRIVATE
  73 #endif
  74 #ifdef MAP_FILE
  75                        | MAP_FILE
  76 #endif
  77                        , fd, 0);
  78       if (result == (void *) -1)
  79         result = NULL;
  80       else
  81         *sizep = st.st_size;
  82     }
  83   __close (fd);
  84   return result;
  85 }