e206feb881
function. It was an ill-considered feature. It didn't solve the problem I wanted it to solve. And it added Yet Another Version Number that would have to be maintained at every release point. I'm nuking it now before anybody grows too fond of it.
169 lines
4.3 KiB
C
169 lines
4.3 KiB
C
/*-
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* Copyright (c) 1998 John D. Polstra
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: dlfcn.c,v 1.2 1998/03/07 19:57:05 jdp Exp $
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*/
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/*
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* Linkage to services provided by the dynamic linker. These are
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* implemented differently in ELF and a.out, because the dynamic
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* linkers have different interfaces.
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*/
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#ifdef __ELF__
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#include <dlfcn.h>
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#include <stddef.h>
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static const char sorry[] = "Service unavailable";
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/*
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* For ELF, the dynamic linker directly resolves references to its
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* services to functions inside the dynamic linker itself. These
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* weak-symbol stubs are necessary so that "ld" won't complain about
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* undefined symbols. The stubs are executed only when the program is
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* linked statically, or when a given service isn't implemented in the
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* dynamic linker. They must return an error if called, and they must
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* be weak symbols so that the dynamic linker can override them.
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*/
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#pragma weak _rtld_error
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void
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_rtld_error(const char *fmt, ...)
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{
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}
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#pragma weak dladdr
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int
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dladdr(const void *addr, Dl_info *dlip)
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{
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_rtld_error(sorry);
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return 0;
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}
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#pragma weak dlclose
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int
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dlclose(void *handle)
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{
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_rtld_error(sorry);
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return -1;
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}
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#pragma weak dlerror
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const char *
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dlerror(void)
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{
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return sorry;
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}
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#pragma weak dlopen
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void *
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dlopen(const char *name, int mode)
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{
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_rtld_error(sorry);
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return NULL;
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}
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#pragma weak dlsym
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void *
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dlsym(void *handle, const char *name)
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{
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_rtld_error(sorry);
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return NULL;
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}
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#else /* a.out format */
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#include <sys/types.h>
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#include <nlist.h> /* XXX - Required by link.h */
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#include <dlfcn.h>
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#include <link.h>
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#include <stddef.h>
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/*
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* For a.out, entry to the dynamic linker is via these trampolines.
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* They enter the dynamic linker through the ld_entry struct that was
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* passed back from the dynamic linker at startup time.
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*/
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/* GCC is needed because we use its __builtin_return_address construct. */
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#ifndef __GNUC__
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#error "GCC is needed to compile this file"
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#endif
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/*
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* These variables are set by code in crt0.o. For compatibility with
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* old executables, they must be common, not extern.
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*/
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struct ld_entry *__ldso_entry; /* Entry points to dynamic linker */
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int __ldso_version; /* Dynamic linker version number */
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int
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dladdr(const void *addr, Dl_info *dlip)
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{
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if (__ldso_entry == NULL || __ldso_version < LDSO_VERSION_HAS_DLADDR)
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return 0;
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return (__ldso_entry->dladdr)(addr, dlip);
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}
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int
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dlclose(void *handle)
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{
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if (__ldso_entry == NULL)
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return -1;
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return (__ldso_entry->dlclose)(handle);
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}
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const char *
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dlerror(void)
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{
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if (__ldso_entry == NULL)
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return "Service unavailable";
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return (__ldso_entry->dlerror)();
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}
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void *
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dlopen(const char *name, int mode)
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{
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if (__ldso_entry == NULL)
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return NULL;
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return (__ldso_entry->dlopen)(name, mode);
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}
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void *
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dlsym(void *handle, const char *name)
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{
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if (__ldso_entry == NULL)
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return NULL;
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if (__ldso_version >= LDSO_VERSION_HAS_DLSYM3) {
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void *retaddr = __builtin_return_address(0); /* __GNUC__ only */
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return (__ldso_entry->dlsym3)(handle, name, retaddr);
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} else
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return (__ldso_entry->dlsym)(handle, name);
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}
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#endif /* __ELF__ */
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