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 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