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 /* XXX I know about at least one case where we depend on the old weak
  47    behavior (it has to do with librt).  Until we get DSO groups implemented
  48    we have to make this the default.  Bummer. --drepper  */
  49 #if 0
  50 int _dl_dynamic_weak;
  51 #else
  52 int _dl_dynamic_weak = 1;
  53 #endif
  54
  55 /* If nonzero print warnings about problematic situations.  */
  56 int _dl_verbose;
  57
  58 /* Structure to store information about search paths.  */
  59 struct r_search_path *_dl_search_paths;
  60
  61 /* We never do profiling.  */
  62 const char *_dl_profile;
  63
  64 /* Names of shared object for which the RUNPATHs and RPATHs should be
  65    ignored.  */
  66 const char *_dl_inhibit_rpath;
  67
  68 /* The map for the object we will profile.  */
  69 struct link_map *_dl_profile_map;
  70
  71 /* This is the address of the last stack address ever used.  */
  72 void *__libc_stack_end;
  73
  74 /* Path where the binary is found.  */
  75 const char *_dl_origin_path;
  76
  77 /* Nonzero if runtime lookup should not update the .got/.plt.  */
  78 int _dl_bind_not;
  79
  80 /* Initially empty list of loaded objects.  */
  81 struct link_map *_dl_loaded;
  82 /* Number of object in the _dl_loaded list.  */
  83 unsigned int _dl_nloaded;
  84
  85 /* Fake scope.  In dynamically linked binaries this is the scope of the
  86    main application but here we don't have something like this.  So
  87    create a fake scope containing nothing.  */
  88 struct r_scope_elem _dl_initial_searchlist;
  89 /* Variable which can be used in lookup to process the global scope.  */
  90 struct r_scope_elem *_dl_global_scope[2] = { &_dl_initial_searchlist, NULL };
  91 /* This is a global pointer to this structure which is public.  It is
  92    used by dlopen/dlclose to add and remove objects from what is regarded
  93    to be the global scope.  */
  94 struct r_scope_elem *_dl_main_searchlist = &_dl_initial_searchlist;
  95
  96 /* Nonzero during startup.  */
  97 int _dl_starting_up = 1;
  98
  99 /* During the program run we must not modify the global data of
 100    loaded shared object simultanously in two threads.  Therefore we
 101    protect `_dl_open' and `_dl_close' in dl-close.c.
 102
 103    This must be a recursive lock since the initializer function of
 104    the loaded object might as well require a call to this function.
 105    At this time it is not anymore a problem to modify the tables.  */
 106 __libc_lock_define_initialized_recursive (, _dl_load_lock)
 107
 108
 109 static void non_dynamic_init (void) __attribute__ ((unused));
 110
 111 static void
 112 non_dynamic_init (void)
 113 {
 114   _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1;
 115
 116   _dl_pagesize = __getpagesize ();
 117
 118   /* Initialize the data structures for the search paths for shared
 119      objects.  */
 120   _dl_init_paths (getenv ("LD_LIBRARY_PATH"));
 121
 122   _dl_lazy = *(getenv ("LD_BIND_NOW") ?: "") == '\0';
 123
 124   _dl_bind_not = *(getenv ("LD_BIND_NOT") ?: "") != '\0';
 125
 126   _dl_dynamic_weak = *(getenv ("LD_DYNAMIC_WEAK") ?: "") == '\0';
 127
 128 #ifdef DL_PLATFORM_INIT
 129   DL_PLATFORM_INIT;
 130 #endif
 131
 132   /* Now determine the length of the platform string.  */
 133   if (_dl_platform != NULL)
 134     _dl_platformlen = strlen (_dl_platform);
 135 }
 136 text_set_element (__libc_subinit, non_dynamic_init);
 137
 138 const struct r_strlenpair *
 139 internal_function
 140 _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
 141                       size_t *max_capstrlen)
 142 {
 143   struct r_strlenpair *result;
 144
 145   /* XXX We don't try to find the capabilities in this case.  */
 146   result = (struct r_strlenpair *) malloc (sizeof (*result));
 147   if (result == NULL)
 148     _dl_signal_error (ENOMEM, NULL, N_("cannot create capability list"));
 149
 150   result[0].str = (char *) result;      /* Does not really matter.  */
 151   result[0].len = 0;
 152
 153   *sz = 1;
 154   return result;
 155 }