glibc/include/set-hooks.h
Samuel Thibault ae49f218da hurd: Fix static-PIE startup
hurd initialization stages use RUN_HOOK to run various initialization
functions.  That is however using absolute addresses which need to be
relocated, which is done later by csu.  We can however easily make the
linker compute relative addresses which thus don't need a relocation.
The new SET_RELHOOK and RUN_RELHOOK macros implement this.
2021-12-28 10:28:22 +01:00

97 lines
3.2 KiB
C

/* Macros for using symbol sets for running lists of functions.
Copyright (C) 1994-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _SET_HOOKS_H
#define _SET_HOOKS_H 1
#define __need_size_t
#include <stddef.h>
#include <sys/cdefs.h>
#include <libc-symbols.h>
#include "set-hooks-arch.h"
#ifdef symbol_set_define
/* Define a hook variable called NAME. Functions put on this hook take
arguments described by PROTO. Use `text_set_element (NAME, FUNCTION)'
from include/libc-symbols.h to add a function to the hook. */
# define DEFINE_HOOK(NAME, PROTO) \
typedef void __##NAME##_hook_function_t PROTO; \
symbol_set_define (NAME)
# define DECLARE_HOOK(NAME, PROTO) \
typedef void __##NAME##_hook_function_t PROTO;\
symbol_set_declare (NAME)
/* Run all the functions hooked on the set called NAME.
Each function is called like this: `function ARGS'. */
# define RUN_HOOK(NAME, ARGS) \
do { \
void *const *ptr; \
for (ptr = (void *const *) symbol_set_first_element (NAME); \
! symbol_set_end_p (NAME, ptr); ++ptr) \
(*(__##NAME##_hook_function_t *) *ptr) ARGS; \
} while (0)
/* Define a hook variable with NAME and PROTO, and a function called RUNNER
which calls each function on the hook in turn, with ARGS. */
# define DEFINE_HOOK_RUNNER(name, runner, proto, args) \
DEFINE_HOOK (name, proto); \
extern void runner proto; void runner proto { RUN_HOOK (name, args); }
# ifdef SET_RELHOOK
/* This is similar to RUN_RELHOOK, but the hooks were registered with
* SET_RELHOOK so that a relative offset was computed by the linker
* rather than an absolute address by the dynamic linker. */
# define RUN_RELHOOK(NAME, ARGS) \
do { \
void *const *ptr; \
for (ptr = (void *const *) symbol_set_first_element (NAME); \
! symbol_set_end_p (NAME, ptr); ++ptr) { \
__##NAME##_hook_function_t *f = \
(void*) ((uintptr_t) ptr + (ptrdiff_t) *ptr); \
(*f) ARGS; \
} \
} while (0)
# else
# define SET_RELHOOK(NAME, HOOK) text_set_element (NAME, HOOK)
# define RUN_RELHOOK(NAME, ARGS) RUN_HOOK(NAME, ARGS)
# endif
#else
/* The system does not provide necessary support for this. */
# define DEFINE_HOOK(NAME, PROTO)
# define DECLARE_HOOK(NAME, PROTO)
# define RUN_HOOK(NAME, ARGS)
# define DEFINE_HOOK_RUNNER(name, runner, proto, args)
# define SET_RELHOOK(NAME, HOOK)
# define RUN_RELHOOK(NAME, ARGS)
#endif
#endif /* set-hooks.h */