xref: /openbsd-src/lib/csu/crtbegin.c (revision a36635a7c3589c5da52fd2716a34be60855ef6d2)
1 /*	$OpenBSD: crtbegin.c,v 1.26 2019/01/09 16:42:38 visa Exp $	*/
2 /*	$NetBSD: crtbegin.c,v 1.1 1996/09/12 16:59:03 cgd Exp $	*/
3 
4 /*
5  * Copyright (c) 1993 Paul Kranenburg
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *      This product includes software developed by Paul Kranenburg.
19  * 4. The name of the author may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 /*
35  * Run-time module for GNU C++ compiled shared libraries.
36  *
37  * The linker constructs the following arrays of pointers to global
38  * constructors and destructors. The first element contains the
39  * number of pointers in each.
40  * The tables are also null-terminated.
41  */
42 #include <stdlib.h>
43 
44 #include "md_init.h"
45 #include "os-note-elf.h"
46 #include "extern.h"
47 
48 struct dwarf2_eh_object {
49 	void *space[8];
50 };
51 
52 void __register_frame_info(const void *, struct dwarf2_eh_object *)
53     __attribute__((weak));
54 
__register_frame_info(const void * begin,struct dwarf2_eh_object * ob)55 void __register_frame_info(const void *begin, struct dwarf2_eh_object *ob)
56 {
57 }
58 
59 MD_DATA_SECTION_FLAGS_SYMBOL(".eh_frame", "a", const void *, __EH_FRAME_BEGIN__);
60 
61 /*
62  * java class registration hooks
63  */
64 
65 MD_DATA_SECTION_FLAGS_SYMBOL(".jcr", "aw", void *, __JCR_LIST__);
66 
67 extern void _Jv_RegisterClasses (void *)
68     __attribute__((weak));
69 
70 
71 /*
72  * Include support for the __cxa_atexit/__cxa_finalize C++ abi for
73  * gcc > 2.x. __dso_handle is NULL in the main program and a unique
74  * value for each C++ shared library. For more info on this API, see:
75  *
76  *     http://www.codesourcery.com/cxx-abi/abi.html#dso-dtor
77  */
78 
79 void *__dso_handle = NULL;
80 __asm(".hidden  __dso_handle");
81 
82 long __guard_local __dso_hidden __attribute__((section(".openbsd.randomdata")));
83 
84 MD_DATA_SECTION_SYMBOL_VALUE(".ctors", init_f, __CTOR_LIST__, -1);
85 MD_DATA_SECTION_SYMBOL_VALUE(".dtors", init_f, __DTOR_LIST__, -1);
86 
87 
88 static void
__ctors(void)89 __ctors(void)
90 {
91 	unsigned long i = (unsigned long) __CTOR_LIST__[0];
92 	const init_f *p;
93 
94 	if (i == -1)  {
95 		for (i = 1; __CTOR_LIST__[i] != NULL; i++)
96 			;
97 		i--;
98 	}
99 	p = __CTOR_LIST__ + i;
100 	while (i--)
101 		(**p--)();
102 }
103 
104 static void
__dtors(void)105 __dtors(void)
106 {
107 	const init_f *p = __DTOR_LIST__ + 1;
108 
109 	while (*p)
110 		(**p++)();
111 }
112 
113 void __init(void);
114 void __fini(void);
115 static void __do_init(void) __used;
116 static void __do_fini(void) __used;
117 
118 MD_SECTION_PROLOGUE(".init", __init);
119 
120 MD_SECTION_PROLOGUE(".fini", __fini);
121 
122 MD_SECT_CALL_FUNC(".init", __do_init);
123 MD_SECT_CALL_FUNC(".fini", __do_fini);
124 
125 
126 static void
__do_init(void)127 __do_init(void)
128 {
129 	static int initialized;
130 	static struct dwarf2_eh_object object;
131 
132 	/*
133 	 * Call global constructors.
134 	 * Arrange to call global destructors at exit.
135 	 */
136 	if (!initialized) {
137 		initialized = 1;
138 
139 		__register_frame_info(__EH_FRAME_BEGIN__, &object);
140 		if (__JCR_LIST__[0] && _Jv_RegisterClasses)
141 			_Jv_RegisterClasses(__JCR_LIST__);
142 		__ctors();
143 
144 		atexit(__fini);
145 	}
146 }
147 
148 char __csu_do_fini_array __dso_hidden = 0;
149 extern __dso_hidden init_f __fini_array_start[], __fini_array_end[];
150 
151 static void
__do_fini(void)152 __do_fini(void)
153 {
154 	static int finalized;
155 
156 	if (!finalized) {
157 		finalized = 1;
158 		/*
159 		 * Call global destructors.
160 		 */
161 		__dtors();
162 
163 		if (__csu_do_fini_array) {
164 			size_t i = __fini_array_end - __fini_array_start;
165 			while (i-- > 0)
166 				__fini_array_start[i]();
167 		}
168 
169 	}
170 }
171 
172