diff --git a/hurd/dtable.c b/hurd/dtable.c index bbd3bfc892..4f081f09fd 100644 --- a/hurd/dtable.c +++ b/hurd/dtable.c @@ -36,7 +36,7 @@ DEFINE_HOOK (_hurd_fd_subinit, (void)); /* Initialize the file descriptor table at startup. */ -static void +static void attribute_used_retain init_dtable (void) { int i; @@ -91,12 +91,10 @@ init_dtable (void) /* Run things that want to run after the file descriptor table is initialized. */ - RUN_HOOK (_hurd_fd_subinit, ()); - - (void) &init_dtable; /* Avoid "defined but not used" warning. */ + RUN_RELHOOK (_hurd_fd_subinit, ()); } -text_set_element (_hurd_subinit, init_dtable); +SET_RELHOOK (_hurd_subinit, init_dtable); /* XXX when the linker supports it, the following functions should all be elsewhere and just have text_set_elements here. */ diff --git a/hurd/hurdid.c b/hurd/hurdid.c index 70c46c0740..b220532c35 100644 --- a/hurd/hurdid.c +++ b/hurd/hurdid.c @@ -17,6 +17,7 @@ #include #include +#include "set-hooks.h" struct hurd_id_data _hurd_id; @@ -74,7 +75,7 @@ _hurd_check_ids (void) return 0; } -static void +static void attribute_used_retain init_id (void) { __mutex_init (&_hurd_id.lock); @@ -84,7 +85,5 @@ init_id (void) _hurd_id.gen.nuids = _hurd_id.aux.nuids = 0; _hurd_id.gen.gids = _hurd_id.aux.gids = NULL; _hurd_id.gen.ngids = _hurd_id.aux.ngids = 0; - - (void) &init_id; /* Avoid "defined but not used" warning. */ } -text_set_element (_hurd_preinit_hook, init_id); +SET_RELHOOK (_hurd_preinit_hook, init_id); diff --git a/hurd/hurdinit.c b/hurd/hurdinit.c index d4d219a083..9377d902d2 100644 --- a/hurd/hurdinit.c +++ b/hurd/hurdinit.c @@ -108,7 +108,7 @@ _hurd_init (int flags, char **argv, /* Call other things which want to do some initialization. These are not on the __libc_subinit hook because things there like to be able to assume the availability of the POSIX.1 services we provide. */ - RUN_HOOK (_hurd_subinit, ()); + RUN_RELHOOK (_hurd_subinit, ()); } libc_hidden_def (_hurd_init) @@ -190,7 +190,7 @@ _hurd_new_proc_init (char **argv, /* Call other things which want to do some initialization. These are not on the _hurd_subinit hook because things there assume that things done here, like _hurd_pid, are already initialized. */ - RUN_HOOK (_hurd_proc_subinit, ()); + RUN_RELHOOK (_hurd_proc_subinit, ()); /* XXX This code should probably be removed entirely at some point. This conditional should make it reasonably usable with old gdb's for a @@ -242,7 +242,7 @@ _hurd_setproc (process_t procserver) /* Call these functions again so they can fetch the new information from the new proc server. */ - RUN_HOOK (_hurd_proc_subinit, ()); + RUN_RELHOOK (_hurd_proc_subinit, ()); if (_hurd_pgrp != oldpgrp) { diff --git a/hurd/hurdmalloc.c b/hurd/hurdmalloc.c index 7046bcef33..ccb8fc8b54 100644 --- a/hurd/hurdmalloc.c +++ b/hurd/hurdmalloc.c @@ -1,5 +1,6 @@ #include #include +#include "set-hooks.h" #include "hurdmalloc.h" /* XXX see that file */ @@ -148,7 +149,7 @@ static struct free_list malloc_free_list[NBUCKETS]; It preserves the values of data variables like malloc_free_list, but does not save the vm_allocate'd space allocated by this malloc. */ -static void +static void attribute_used_retain malloc_init (void) { int i; @@ -160,11 +161,6 @@ malloc_init (void) malloc_free_list[i].in_use = 0; #endif } - - /* This not only suppresses a `defined but not used' warning, - but it is ABSOLUTELY NECESSARY to avoid the hyperclever - compiler from "optimizing out" the entire function! */ - (void) &malloc_init; } static void @@ -445,4 +441,4 @@ _hurd_malloc_fork_child(void) } -text_set_element (_hurd_preinit_hook, malloc_init); +SET_RELHOOK (_hurd_preinit_hook, malloc_init); diff --git a/hurd/hurdpid.c b/hurd/hurdpid.c index 9014de58e9..613ca357c6 100644 --- a/hurd/hurdpid.c +++ b/hurd/hurdpid.c @@ -17,11 +17,12 @@ #include #include +#include "set-hooks.h" pid_t _hurd_pid, _hurd_ppid, _hurd_pgrp; int _hurd_orphaned; -static void +static void attribute_used_retain init_pids (void) { __USEPORT (PROC, @@ -29,11 +30,9 @@ init_pids (void) __proc_getpids (port, &_hurd_pid, &_hurd_ppid, &_hurd_orphaned); __proc_getpgrp (port, _hurd_pid, &_hurd_pgrp); })); - - (void) &init_pids; /* Avoid "defined but not used" warning. */ } -text_set_element (_hurd_proc_subinit, init_pids); +SET_RELHOOK (_hurd_proc_subinit, init_pids); #include #include "set-hooks.h" diff --git a/hurd/hurdrlimit.c b/hurd/hurdrlimit.c index 17535c2851..4d16bd4f3f 100644 --- a/hurd/hurdrlimit.c +++ b/hurd/hurdrlimit.c @@ -19,6 +19,7 @@ #include #include #include +#include "set-hooks.h" /* This must be given an initializer, or the a.out linking rules will not include the entire file when this symbol is referenced. */ @@ -29,7 +30,7 @@ struct rlimit _hurd_rlimits[RLIM_NLIMITS] = { { 0, }, }; mutex_init is still required below just in case of unexec. */ struct mutex _hurd_rlimit_lock = { SPIN_LOCK_INITIALIZER, }; -static void +static void attribute_used_retain init_rlimit (void) { int i; @@ -52,7 +53,5 @@ init_rlimit (void) } #undef I } - - (void) &init_rlimit; } -text_set_element (_hurd_preinit_hook, init_rlimit); +SET_RELHOOK (_hurd_preinit_hook, init_rlimit); diff --git a/hurd/hurdsock.c b/hurd/hurdsock.c index 04e86b4324..116326b2f2 100644 --- a/hurd/hurdsock.c +++ b/hurd/hurdsock.c @@ -25,6 +25,7 @@ #include <_itoa.h> #include /* For `struct mutex'. */ #include "hurdmalloc.h" /* XXX */ +#include "set-hooks.h" static struct mutex lock; @@ -109,7 +110,7 @@ retry: return server; } -static void +static void attribute_used_retain init (void) { int i; @@ -118,7 +119,5 @@ init (void) for (i = 0; i < max_domain; ++i) servers[i] = MACH_PORT_NULL; - - (void) &init; /* Avoid "defined but not used" warning. */ } -text_set_element (_hurd_preinit_hook, init); +SET_RELHOOK (_hurd_preinit_hook, init); diff --git a/include/set-hooks.h b/include/set-hooks.h index a60b5ae19f..1a2f6ad56b 100644 --- a/include/set-hooks.h +++ b/include/set-hooks.h @@ -24,6 +24,8 @@ #include #include +#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)' @@ -55,6 +57,25 @@ do { \ 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. */ @@ -66,6 +87,10 @@ extern void runner proto; void runner proto { 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 */ diff --git a/sysdeps/generic/set-hooks-arch.h b/sysdeps/generic/set-hooks-arch.h new file mode 100644 index 0000000000..4b47fa2f2e --- /dev/null +++ b/sysdeps/generic/set-hooks-arch.h @@ -0,0 +1,31 @@ +/* Machine-dependent macros for using symbol sets for running lists of + functions. Generic/stub version. + Copyright (C) 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 + . */ + +#ifndef _SET_HOOKS_ARCH_H +#define _SET_HOOKS_ARCH_H + +/* Define SET_RELHOOK to a variant of text_set_element that records a relative + offset rather than an absolute address. See sysdeps/i386/set-hooks-arch.h + for an example. + +#define SET_RELHOOK(NAME, HOOK) ... + + */ + +#endif /* set_hooks_arch.h */ diff --git a/sysdeps/i386/set-hooks-arch.h b/sysdeps/i386/set-hooks-arch.h new file mode 100644 index 0000000000..97513bf897 --- /dev/null +++ b/sysdeps/i386/set-hooks-arch.h @@ -0,0 +1,28 @@ +/* Machine-dependent macros for using symbol sets for running lists of + functions. i386 version. + Copyright (C) 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 + . */ + +#ifndef _SET_HOOKS_ARCH_H +#define _SET_HOOKS_ARCH_H + +#define SET_RELHOOK(NAME, HOOK) \ + asm(".section " #NAME",\"aR\"\n" \ + ".long "#HOOK" - .\n" \ + ".section .text"); + +#endif /* set_hooks_arch.h */ diff --git a/sysdeps/mach/hurd/brk.c b/sysdeps/mach/hurd/brk.c index a4294b9eae..088c99b2c8 100644 --- a/sysdeps/mach/hurd/brk.c +++ b/sysdeps/mach/hurd/brk.c @@ -21,6 +21,8 @@ #include /* For `struct mutex'. */ #include +#include "set-hooks.h" + /* Initial maximum size of the data segment (this is arbitrary). */ #define DATA_SIZE (128 * 1024 * 1024) @@ -130,7 +132,7 @@ _hurd_set_brk (vm_address_t addr) return 0; } -static void +static void attribute_used_retain init_brk (void) { vm_address_t pagend; @@ -160,7 +162,5 @@ init_brk (void) /* Couldn't allocate the memory. The break will be very short. */ _hurd_data_end = pagend; } - - (void) &init_brk; /* Avoid ``defined but not used'' warning. */ } -text_set_element (_hurd_preinit_hook, init_brk); +SET_RELHOOK (_hurd_preinit_hook, init_brk); diff --git a/sysdeps/mach/hurd/check_fds.c b/sysdeps/mach/hurd/check_fds.c index 155e9dd3e9..61e6055d35 100644 --- a/sysdeps/mach/hurd/check_fds.c +++ b/sysdeps/mach/hurd/check_fds.c @@ -79,7 +79,7 @@ check_standard_fds (void) check_one_fd (STDERR_FILENO, O_RDWR); } -static void +static void attribute_used_retain init_standard_fds (void) { /* Now that we have FDs, make sure that, if this is a SUID program, @@ -87,10 +87,8 @@ init_standard_fds (void) ourselves. If that's not possible we stop the program. */ if (__builtin_expect (__libc_enable_secure, 0)) check_standard_fds (); - - (void) &init_standard_fds; /* Avoid "defined but not used" warning. */ } -text_set_element (_hurd_fd_subinit, init_standard_fds); +SET_RELHOOK (_hurd_fd_subinit, init_standard_fds); #ifndef SHARED diff --git a/sysdeps/mach/hurd/i386/init-first.c b/sysdeps/mach/hurd/i386/init-first.c index 5e85aa2bc5..c6ae370daf 100644 --- a/sysdeps/mach/hurd/i386/init-first.c +++ b/sysdeps/mach/hurd/i386/init-first.c @@ -242,7 +242,7 @@ first_init (void) /* Initialize data structures so we can do RPCs. */ __mach_init (); - RUN_HOOK (_hurd_preinit_hook, ()); + RUN_RELHOOK (_hurd_preinit_hook, ()); } #ifdef SHARED diff --git a/sysdeps/x86_64/set-hooks-arch.h b/sysdeps/x86_64/set-hooks-arch.h new file mode 100644 index 0000000000..227d4f8e08 --- /dev/null +++ b/sysdeps/x86_64/set-hooks-arch.h @@ -0,0 +1,28 @@ +/* Machine-dependent macros for using symbol sets for running lists of + functions. x86-64 version. + Copyright (C) 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 + . */ + +#ifndef _SET_HOOKS_ARCH_H +#define _SET_HOOKS_ARCH_H + +#define SET_RELHOOK(NAME, HOOK) \ + asm(".section " #NAME",\"aR\"\n" \ + ".quad "#HOOK" - .\n" \ + ".section .text"); + +#endif /* set_hooks_arch.h */