freebsd-dev/include/dlfcn.h
John Polstra 3600eb76c6 Work around an assert failure in the dynamic linker's default thread
locking functions.  If an application loads a shared object with
dlopen() and the shared object has an init function which requires
lazy binding, then _rtld_bind is called when the thread is already
inside the dynamic linker.  This leads to a recursive acquisition
of the lock, which I was not expecting -- hence the assert failure.

This work-around makes the default locking functions handle recursive
locking.  It is NOT the correct fix -- that should be implemented
at the generic locking level rather than in the default locking
functions.  I will implement the correct fix in a future commit.

Since the dllockinit() interface will likely need to change, warn
about that in both the man page and the header file.
1999-12-28 04:38:17 +00:00

82 lines
3.2 KiB
C

/*
* Copyright (c) 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _DLFCN_H_
#define _DLFCN_H_
#include <sys/cdefs.h>
/*
* Modes and flags for dlopen().
*/
#define RTLD_LAZY 1 /* Bind function calls lazily */
#define RTLD_NOW 2 /* Bind function calls immediately */
#define RTLD_MODEMASK 0x3
#define RTLD_GLOBAL 0x100 /* Make symbols globally available */
/*
* Special handle argument for dlsym(). It causes the search for the
* symbol to begin in the next shared object after the one containing
* the caller.
*/
#define RTLD_NEXT ((void *) -1)
/*
* Structure filled in by dladdr().
*/
typedef struct dl_info {
const char *dli_fname; /* Pathname of shared object */
void *dli_fbase; /* Base address of shared object */
const char *dli_sname; /* Name of nearest symbol */
void *dli_saddr; /* Address of nearest symbol */
} Dl_info;
__BEGIN_DECLS
int dladdr __P((const void *, Dl_info *));
int dlclose __P((void *));
const char *dlerror __P((void));
/* XXX dllockinit() interface is likely to change. */
void dllockinit __P((void *_context,
void *(*_lock_create)(void *_context),
void (*_rlock_acquire)(void *_lock),
void (*_wlock_acquire)(void *_lock),
void (*_lock_release)(void *_lock),
void (*_lock_destroy)(void *_lock),
void (*_context_destroy)(void *_context)));
void *dlopen __P((const char *, int));
void *dlsym __P((void *, const char *));
__END_DECLS
#endif /* !_DLFCN_H_ */