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