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 not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, 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 #ifndef MAP_ANON
  37 /* This is the only dl-sysdep.c function that is actually needed at run-time
  38    by _dl_map_object.  */
  39
  40 int
  41 _dl_sysdep_open_zero_fill (void)
  42 {
  43   return __open ("/dev/zero", O_RDONLY);
  44 }
  45 #endif
  46
  47 /* This should never be called.  */
  48 void
  49 _dl_sysdep_fatal (void)
  50 {
  51   assert (! "_dl_sysdep_fatal called");
  52 }
  53
  54 /* Read the whole contents of FILE into new mmap'd space with given
  55    protections.  *SIZEP gets the size of the file.  */
  56
  57 void *
  58 _dl_sysdep_read_whole_file (const char *file, size_t *sizep, int prot)
  59 {
  60   void *result;
  61   struct stat st;
  62   int fd = __open (file, O_RDONLY);
  63   if (fd < 0)
  64     return NULL;
  65   if (__fstat (fd, &st) < 0)
  66     result = NULL;
  67   else
  68     {
  69       /* Map a copy of the file contents.  */
  70       result = __mmap (0, st.st_size, prot,
  71 #ifdef MAP_COPY
  72                        MAP_COPY
  73 #else
  74                        MAP_PRIVATE
  75 #endif
  76 #ifdef MAP_FILE
  77                        | MAP_FILE
  78 #endif
  79                        , fd, 0);
  80       if (result == (void *) -1)
  81         result = NULL;
  82       else
  83         *sizep = st.st_size;
  84     }
  85   __close (fd);
  86   return result;
  87 }