1/* Macros for using symbol sets for running lists of functions.
2 Copyright (C) 1994-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#ifndef _SET_HOOKS_H
20#define _SET_HOOKS_H 1
21
22#define __need_size_t
23#include <stddef.h>
24#include <sys/cdefs.h>
25#include <libc-symbols.h>
26
27#include "set-hooks-arch.h"
28
29#ifdef symbol_set_define
30/* Define a hook variable called NAME. Functions put on this hook take
31 arguments described by PROTO. Use `text_set_element (NAME, FUNCTION)'
32 from include/libc-symbols.h to add a function to the hook. */
33
34# define DEFINE_HOOK(NAME, PROTO) \
35 typedef void __##NAME##_hook_function_t PROTO; \
36 symbol_set_define (NAME)
37
38# define DECLARE_HOOK(NAME, PROTO) \
39 typedef void __##NAME##_hook_function_t PROTO;\
40 symbol_set_declare (NAME)
41
42/* Run all the functions hooked on the set called NAME.
43 Each function is called like this: `function ARGS'. */
44
45# define RUN_HOOK(NAME, ARGS) \
46do { \
47 void *const *ptr; \
48 for (ptr = (void *const *) symbol_set_first_element (NAME); \
49 ! symbol_set_end_p (NAME, ptr); ++ptr) \
50 (*(__##NAME##_hook_function_t *) *ptr) ARGS; \
51} while (0)
52
53/* Define a hook variable with NAME and PROTO, and a function called RUNNER
54 which calls each function on the hook in turn, with ARGS. */
55
56# define DEFINE_HOOK_RUNNER(name, runner, proto, args) \
57DEFINE_HOOK (name, proto); \
58extern void runner proto; void runner proto { RUN_HOOK (name, args); }
59
60# ifdef SET_RELHOOK
61/* This is similar to RUN_RELHOOK, but the hooks were registered with
62 * SET_RELHOOK so that a relative offset was computed by the linker
63 * rather than an absolute address by the dynamic linker. */
64# define RUN_RELHOOK(NAME, ARGS) \
65do { \
66 void *const *ptr; \
67 for (ptr = (void *const *) symbol_set_first_element (NAME); \
68 ! symbol_set_end_p (NAME, ptr); ++ptr) { \
69 __##NAME##_hook_function_t *f = \
70 (void*) ((uintptr_t) ptr + (ptrdiff_t) *ptr); \
71 (*f) ARGS; \
72 } \
73} while (0)
74# else
75# define SET_RELHOOK(NAME, HOOK) text_set_element (NAME, HOOK)
76# define RUN_RELHOOK(NAME, ARGS) RUN_HOOK(NAME, ARGS)
77# endif
78
79#else
80
81/* The system does not provide necessary support for this. */
82# define DEFINE_HOOK(NAME, PROTO)
83
84# define DECLARE_HOOK(NAME, PROTO)
85
86# define RUN_HOOK(NAME, ARGS)
87
88# define DEFINE_HOOK_RUNNER(name, runner, proto, args)
89
90# define SET_RELHOOK(NAME, HOOK)
91
92# define RUN_RELHOOK(NAME, ARGS)
93
94#endif
95
96#endif /* set-hooks.h */
97