xref: /freebsd/lib/csu/common/crtend.c (revision de3deff65c5b407ab29b45780f2585b3bc24bbd6)
1 /*-
2  * SPDX-License-Identifier: BSD-1-Clause
3  *
4  * Copyright 2018 Andrew Turner
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  *
12  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
13  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
14  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
15  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
16  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
17  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
18  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
19  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
20  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
21  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
22  */
23 
24 #include <sys/types.h>
25 #include "crt.h"
26 
27 typedef void (*crt_func)(void);
28 
29 static crt_func __JCR_END__[] __section(".jcr") __used = {
30 	(crt_func)0
31 };
32 
33 #ifdef HAVE_CTORS
34 
35 /*
36  * On some architectures and toolchains we may need to call the .ctors.
37  * These are called in the reverse order they are in the ELF file.
38  */
39 static void __do_global_ctors_aux(void) __used;
40 
41 static crt_func __CTOR_END__[] __section(".ctors") __used = {
42 	(crt_func)0
43 };
44 static crt_func __DTOR_END__[] __section(".dtors") __used = {
45 	(crt_func)0
46 };
47 
48 extern const char startof_ctors[] __asm(".startof..ctors")
49     __weak_symbol __hidden;
50 
51 static void
52 __do_global_ctors_aux(void)
53 {
54 	crt_func fn;
55 	uintptr_t ctors_start;
56 	int n;
57 
58 	ctors_start = (uintptr_t)&startof_ctors;
59 	for (n = 1;; n++) {
60 		fn = __CTOR_END__[-n];
61 		if (fn == (crt_func)0 || fn == (crt_func)-1 ||
62 		    (ctors_start > 0 &&
63 		    (uintptr_t)&__CTOR_END__[-n] < ctors_start))
64 			break;
65 		fn();
66 	}
67 }
68 
69 asm (
70     ".pushsection .init		\n"
71     "\t" INIT_CALL_SEQ(__do_global_ctors_aux) "\n"
72     ".popsection		\n"
73 );
74 #endif
75