xref: /freebsd/libexec/rtld-elf/rtld_lock.h (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright 2003 Alexander Kabaev.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  *
27  * $FreeBSD$
28  */
29 
30 #ifndef _RTLD_LOCK_H_
31 #define	_RTLD_LOCK_H_
32 
33 #define	RTLI_VERSION_ONE	0x01
34 #define	RTLI_VERSION		0x02
35 
36 #define	MAX_RTLD_LOCKS	8
37 
38 /*
39  * This structure is part of the ABI between rtld and threading
40  * libraries, like libthr and even libc_r.  Its layout is fixed and
41  * can be changed only by appending new fields at the end, with the
42  * bump of RTLI_VERSION.
43  */
44 struct RtldLockInfo
45 {
46 	/*
47 	 * Valid if the object calling _rtld_thread_init() exported
48 	 * symbol _pli_rtli_version.  Otherwise assume RTLI_VERSION_ONE.
49 	 */
50 	unsigned int rtli_version;
51 
52 	void *(*lock_create)(void);
53 	void  (*lock_destroy)(void *);
54 	void  (*rlock_acquire)(void *);
55 	void  (*wlock_acquire)(void *);
56 	void  (*lock_release)(void *);
57 	int   (*thread_set_flag)(int);
58 	int   (*thread_clr_flag)(int);
59 	void  (*at_fork)(void);
60 
61 	/* Version 2 fields */
62 	char *(*dlerror_loc)(void);
63 	int  *(*dlerror_seen)(void);
64 	int   dlerror_loc_sz;
65 };
66 
67 #if defined(IN_RTLD) || defined(PTHREAD_KERNEL)
68 
69 void _rtld_thread_init(struct RtldLockInfo *) __exported;
70 void _rtld_atfork_pre(int *) __exported;
71 void _rtld_atfork_post(int *) __exported;
72 
73 #endif /* IN_RTLD || PTHREAD_KERNEL */
74 
75 #ifdef IN_RTLD
76 
77 struct rtld_lock;
78 typedef struct rtld_lock *rtld_lock_t;
79 
80 extern rtld_lock_t	rtld_bind_lock;
81 extern rtld_lock_t	rtld_libc_lock;
82 extern rtld_lock_t	rtld_phdr_lock;
83 
84 extern struct RtldLockInfo lockinfo;
85 
86 #define	RTLD_LOCK_UNLOCKED	0
87 #define	RTLD_LOCK_RLOCKED	1
88 #define	RTLD_LOCK_WLOCKED	2
89 
90 struct Struct_RtldLockState;
91 typedef struct Struct_RtldLockState RtldLockState;
92 
93 void	rlock_acquire(rtld_lock_t, RtldLockState *);
94 void 	wlock_acquire(rtld_lock_t, RtldLockState *);
95 void	lock_release(rtld_lock_t, RtldLockState *);
96 void	lock_upgrade(rtld_lock_t, RtldLockState *);
97 void	lock_restart_for_upgrade(RtldLockState *);
98 
99 void	dlerror_dflt_init(void);
100 
101 #endif	/* IN_RTLD */
102 
103 #endif
104