80 lines
1.9 KiB
C
80 lines
1.9 KiB
C
/* Look up a symbol in a shared object loaded by `dlopen'.
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Copyright (C) 1995-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <dlfcn.h>
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#include <stddef.h>
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#include <ldsodefs.h>
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#if !defined SHARED && IS_IN (libdl)
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void *
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dlsym (void *handle, const char *name)
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{
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return __dlsym (handle, name, RETURN_ADDRESS (0));
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}
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#else
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struct dlsym_args
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{
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/* The arguments to dlsym_doit. */
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void *handle;
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const char *name;
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void *who;
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/* The return value of dlsym_doit. */
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void *sym;
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};
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static void
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dlsym_doit (void *a)
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{
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struct dlsym_args *args = (struct dlsym_args *) a;
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args->sym = _dl_sym (args->handle, args->name, args->who);
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}
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void *
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__dlsym (void *handle, const char *name DL_CALLER_DECL)
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{
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# ifdef SHARED
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if (__glibc_unlikely (_dlfcn_hook != NULL))
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return _dlfcn_hook->dlsym (handle, name, DL_CALLER);
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# endif
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struct dlsym_args args;
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args.who = DL_CALLER;
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args.handle = handle;
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args.name = name;
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/* Protect against concurrent loads and unloads. */
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__rtld_lock_lock_recursive (GL(dl_load_lock));
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void *result = (_dlerror_run (dlsym_doit, &args) ? NULL : args.sym);
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__rtld_lock_unlock_recursive (GL(dl_load_lock));
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return result;
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}
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# ifdef SHARED
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strong_alias (__dlsym, dlsym)
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# endif
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#endif
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