d3980376e8
functions to be used by the dynamic linker. This can be called by threads packages at start-up time. I will add the call to libc_r soon. Also add a default locking method that is used up until dllockinit() is called. The default method works by blocking SIGVTALRM, SIGPROF, and SIGALRM in critical sections. It is based on the observation that most user-space threads packages implement thread preemption with one of these signals (usually SIGVTALRM). The dynamic linker has never been reentrant, but it became less reentrant in revision 1.34 of "src/libexec/rtld-elf/rtld.c". Starting with that revision, multiple threads each doing lazy binding could interfere with each other. The usual symptom was that a symbol was falsely reported as undefined at start-up time. It was rare but not unseen. This commit fixes it.
81 lines
3.1 KiB
C
81 lines
3.1 KiB
C
/*
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* Copyright (c) 1994
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* The Regents of the University of California. 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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* $FreeBSD$
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*/
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#ifndef _DLFCN_H_
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#define _DLFCN_H_
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#include <sys/cdefs.h>
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/*
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* Modes and flags for dlopen().
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*/
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#define RTLD_LAZY 1 /* Bind function calls lazily */
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#define RTLD_NOW 2 /* Bind function calls immediately */
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#define RTLD_MODEMASK 0x3
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#define RTLD_GLOBAL 0x100 /* Make symbols globally available */
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/*
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* Special handle argument for dlsym(). It causes the search for the
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* symbol to begin in the next shared object after the one containing
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* the caller.
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*/
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#define RTLD_NEXT ((void *) -1)
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/*
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* Structure filled in by dladdr().
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*/
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typedef struct dl_info {
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const char *dli_fname; /* Pathname of shared object */
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void *dli_fbase; /* Base address of shared object */
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const char *dli_sname; /* Name of nearest symbol */
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void *dli_saddr; /* Address of nearest symbol */
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} Dl_info;
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__BEGIN_DECLS
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int dladdr __P((const void *, Dl_info *));
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int dlclose __P((void *));
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const char *dlerror __P((void));
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void dllockinit __P((void *_context,
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void *(*_lock_create)(void *_context),
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void (*_rlock_acquire)(void *_lock),
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void (*_wlock_acquire)(void *_lock),
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void (*_lock_release)(void *_lock),
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void (*_lock_destroy)(void *_lock),
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void (*_context_destroy)(void *_context)));
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void *dlopen __P((const char *, int));
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void *dlsym __P((void *, const char *));
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__END_DECLS
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#endif /* !_DLFCN_H_ */
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