dlfcn/dlopen.c

   1 /* Load a shared object at run time.
   2    Copyright (C) 1995-2022 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <dlfcn.h>
  20 #include <libintl.h>
  21 #include <stddef.h>
  22 #include <unistd.h>
  23 #include <ldsodefs.h>
  24 #include <shlib-compat.h>
  25
  26 struct dlopen_args
  27 {
  28   /* The arguments for dlopen_doit.  */
  29   const char *file;
  30   int mode;
  31   /* The return value of dlopen_doit.  */
  32   void *new;
  33   /* Address of the caller.  */
  34   const void *caller;
  35 };
  36
  37
  38 /* Non-shared code has no support for multiple namespaces.  */
  39 #ifdef SHARED
  40 # define NS __LM_ID_CALLER
  41 #else
  42 # define NS LM_ID_BASE
  43 #endif
  44
  45
  46 static void
  47 dlopen_doit (void *a)
  48 {
  49   struct dlopen_args *args = (struct dlopen_args *) a;
  50
  51   if (args->mode & ~(RTLD_BINDING_MASK | RTLD_NOLOAD | RTLD_DEEPBIND
  52                      | RTLD_GLOBAL | RTLD_LOCAL | RTLD_NODELETE
  53                      | __RTLD_SPROF))
  54     _dl_signal_error (0, NULL, NULL, _("invalid mode parameter"));
  55
  56   args->new = GLRO(dl_open) (args->file ?: "", args->mode | __RTLD_DLOPEN,
  57                              args->caller,
  58                              args->file == NULL ? LM_ID_BASE : NS,
  59                              __libc_argc, __libc_argv, __environ);
  60 }
  61
  62
  63 static void *
  64 dlopen_implementation (const char *file, int mode, void *dl_caller)
  65 {
  66   struct dlopen_args args;
  67   args.file = file;
  68   args.mode = mode;
  69   args.caller = dl_caller;
  70
  71   return _dlerror_run (dlopen_doit, &args) ? NULL : args.new;
  72 }
  73
  74 #ifdef SHARED
  75 void *
  76 ___dlopen (const char *file, int mode)
  77 {
  78   if (GLRO (dl_dlfcn_hook) != NULL)
  79     return GLRO (dl_dlfcn_hook)->dlopen (file, mode, RETURN_ADDRESS (0));
  80   else
  81     return dlopen_implementation (file, mode, RETURN_ADDRESS (0));
  82 }
  83 versioned_symbol (libc, ___dlopen, dlopen, GLIBC_2_34);
  84
  85 # if OTHER_SHLIB_COMPAT (libdl, GLIBC_2_1, GLIBC_2_34)
  86 compat_symbol (libdl, ___dlopen, dlopen, GLIBC_2_1);
  87 # endif
  88 #else /* !SHARED */
  89 /* Also used with _dlfcn_hook.  */
  90 void *
  91 __dlopen (const char *file, int mode, void *dl_caller)
  92 {
  93   return dlopen_implementation (file, mode, RETURN_ADDRESS (0));
  94 }
  95
  96 void *
  97 ___dlopen (const char *file, int mode)
  98 {
  99   return __dlopen (file, mode, RETURN_ADDRESS (0));
 100 }
 101 weak_alias (___dlopen, dlopen)
 102 static_link_warning (dlopen)
 103 #endif /* !SHARED */