1 /* The meat of this file is a copy of the FreeBSD sys/link_set.h */
2 /*
3 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 *
5 * Copyright (c) 1999 John D. Polstra
6 * Copyright (c) 1999,2001 Peter Wemm <peter@FreeBSD.org>
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $FreeBSD$
31 */
32
33 #include <stdio.h>
34
35 #define MAKE_SET(set, sym) \
36 __asm__(".globl __start_set_" #set); \
37 __asm__(".globl __stop_set_" #set); \
38 static __attribute__((section("set_" #set), used)) \
39 void const *__set_##set##_sym_##sym = &(sym)
40
41 /*
42 * Initialize before referring to a given linker set.
43 */
44 #define SET_DECLARE(set, ptype) \
45 extern __attribute__((weak)) ptype *__start_set_ ## set; \
46 extern __attribute__((weak)) ptype *__stop_set_ ## set
47
48 #define SET_BEGIN(set) (&__start_set_ ## set)
49 #define SET_LIMIT(set) (&__stop_set_ ## set)
50
51 /*
52 * Iterate over all the elements of a set.
53 *
54 * Sets always contain addresses of things, and "pvar" points to words
55 * containing those addresses. Thus is must be declared as "type **pvar",
56 * and the address of each set item is obtained inside the loop by "*pvar".
57 */
58 #define SET_FOREACH(pvar, set) \
59 for (pvar = SET_BEGIN(set); pvar < SET_LIMIT(set); pvar++)
60
61 #define SET_ITEM(set, i) \
62 ((SET_BEGIN(set))[i])
63
64 /*
65 * Provide a count of the items in a set.
66 */
67 #define SET_COUNT(set) \
68 (SET_LIMIT(set) - SET_BEGIN(set))
69
70 struct foo {
71 char buf[128];
72 };
73
74 SET_DECLARE(foo, struct foo);
75
76 struct foo a = { "foo" };
77 struct foo b = { "bar" };
78 struct foo c = { "baz" };
79
80 MAKE_SET(foo, a);
81 MAKE_SET(foo, b);
82 MAKE_SET(foo, c);
83
84 int
main(int argc,char ** argv)85 main(int __attribute__((unused)) argc, char __attribute__((unused)) **argv)
86 {
87 struct foo **c;
88 int i = 0;
89
90 printf("Set count: %d\n", SET_COUNT(foo));
91
92
93 printf("a: %s\n", ((struct foo *)__set_foo_sym_a)->buf);
94 printf("b: %s\n", ((struct foo *)__set_foo_sym_b)->buf);
95 printf("c: %s\n", ((struct foo *)__set_foo_sym_c)->buf);
96
97 printf("item(foo, 0): %s\n", SET_ITEM(foo, 0)->buf);
98 printf("item(foo, 1): %s\n", SET_ITEM(foo, 1)->buf);
99 printf("item(foo, 2): %s\n", SET_ITEM(foo, 2)->buf);
100
101 SET_FOREACH(c, foo) {
102 printf("foo[%d]: %s\n", i, (*c)->buf);
103 i++;
104 }
105
106 return (0);
107 }
108