elf/dl-support.c

   1 /* Support for dynamic linking code in static libc.
   2    Copyright (C) 1996,97,98,99,2000 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 /* This file defines some things that for the dynamic linker are defined in
  21    rtld.c and dl-sysdep.c in ways appropriate to bootstrap dynamic linking.  */
  22
  23 #include <errno.h>
  24 #include <libintl.h>
  25 #include <stdlib.h>
  26 #include <unistd.h>
  27 #include <ldsodefs.h>
  28 #include <dl-machine.h>
  29 #include <bits/libc-lock.h>
  30
  31 extern char *__progname;
  32 char **_dl_argv = &__progname;  /* This is checked for some error messages.  */
  33
  34 /* Name of the architecture.  */
  35 const char *_dl_platform;
  36 size_t _dl_platformlen;
  37
  38 int _dl_debug_libs;
  39 int _dl_debug_impcalls;
  40 int _dl_debug_bindings;
  41 int _dl_debug_symbols;
  42 int _dl_debug_versions;
  43 int _dl_debug_reloc;
  44 int _dl_debug_files;
  45 int _dl_lazy;
  46 int _dl_dynamic_weak;
  47
  48 /* If nonzero print warnings about problematic situations.  */
  49 int _dl_verbose;
  50
  51 /* Structure to store information about search paths.  */
  52 struct r_search_path *_dl_search_paths;
  53
  54 /* We never do profiling.  */
  55 const char *_dl_profile;
  56
  57 /* Names of shared object for which the RUNPATHs and RPATHs should be
  58    ignored.  */
  59 const char *_dl_inhibit_rpath;
  60
  61 /* The map for the object we will profile.  */
  62 struct link_map *_dl_profile_map;
  63
  64 /* This is the address of the last stack address ever used.  */
  65 void *__libc_stack_end;
  66
  67 /* Path where the binary is found.  */
  68 const char *_dl_origin_path;
  69
  70 /* Nonzero if runtime lookup should not update the .got/.plt.  */
  71 int _dl_bind_not;
  72
  73 /* Initially empty list of loaded objects.  */
  74 struct link_map *_dl_loaded;
  75
  76 /* Fake scope.  In dynamically linked binaries this is the scope of the
  77    main application but here we don't have something like this.  So
  78    create a fake scope containing nothing.  */
  79 struct r_scope_elem _dl_initial_searchlist;
  80 /* Variable which can be used in lookup to process the global scope.  */
  81 struct r_scope_elem *_dl_global_scope[2] = { &_dl_initial_searchlist, NULL };
  82 /* This is a global pointer to this structure which is public.  It is
  83    used by dlopen/dlclose to add and remove objects from what is regarded
  84    to be the global scope.  */
  85 struct r_scope_elem *_dl_main_searchlist = &_dl_initial_searchlist;
  86
  87 /* Nonzero during startup.  */
  88 int _dl_starting_up = 1;
  89
  90 /* During the program run we must not modify the global data of
  91    loaded shared object simultanously in two threads.  Therefore we
  92    protect `_dl_open' and `_dl_close' in dl-close.c.
  93
  94    This must be a recursive lock since the initializer function of
  95    the loaded object might as well require a call to this function.
  96    At this time it is not anymore a problem to modify the tables.  */
  97 __libc_lock_define_initialized_recursive (, _dl_load_lock)
  98
  99
 100 static void non_dynamic_init (void) __attribute__ ((unused));
 101
 102 static void
 103 non_dynamic_init (void)
 104 {
 105   _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1;
 106
 107   _dl_pagesize = __getpagesize ();
 108
 109   /* Initialize the data structures for the search paths for shared
 110      objects.  */
 111   _dl_init_paths (getenv ("LD_LIBRARY_PATH"));
 112
 113   _dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0';
 114
 115   _dl_bind_not = *(getenv ("LD_BIND_NOT") ?: "") != '\0';
 116
 117   _dl_dynamic_weak = *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0';
 118
 119 #ifdef DL_PLATFORM_INIT
 120   DL_PLATFORM_INIT;
 121 #endif
 122
 123   /* Now determine the length of the platform string.  */
 124   if (_dl_platform != NULL)
 125     _dl_platformlen = strlen (_dl_platform);
 126 }
 127 text_set_element (__libc_subinit, non_dynamic_init);
 128
 129 const struct r_strlenpair *
 130 internal_function
 131 _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
 132                       size_t *max_capstrlen)
 133 {
 134   struct r_strlenpair *result;
 135
 136   /* XXX We don't try to find the capabilities in this case.  */
 137   result = (struct r_strlenpair *) malloc (sizeof (*result));
 138   if (result == NULL)
 139     _dl_signal_error (ENOMEM, NULL, N_("cannot create capability list"));
 140
 141   result[0].str = (char *) result;      /* Does not really matter.  */
 142   result[0].len = 0;
 143
 144   *sz = 1;
 145   return result;
 146 }