mirror of
https://github.com/Zenithsiz/ftmemsim-valgrind.git
synced 2026-02-11 14:01:48 +00:00
247e241160
into a new module m_tooliface. Pretty straightforward. Touches a lot of files because many files use this interface and so need to include the headers for the new module. git-svn-id: svn://svn.valgrind.org/valgrind/trunk@3652
149 lines
3.6 KiB
C
149 lines
3.6 KiB
C
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/*--------------------------------------------------------------------*/
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/*--- Semaphore stuff. linux/sema.c ---*/
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/*--------------------------------------------------------------------*/
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/*
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This file is part of Valgrind, a dynamic binary instrumentation
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framework.
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Copyright (C) 2000-2005 Julian Seward
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jseward@acm.org
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(except where noted below)
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307, USA.
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The GNU General Public License is contained in the file COPYING.
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*/
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#include "core.h"
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#if FUTEX_SEMA
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/*
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Futex-based semaphore operations.
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Taken from futex-2.2/usersem.c
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Based on work by Matthew Kirkwood <matthew@hairy.beasts.org>.
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*/
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#define FUTEX_PASSED (-(1024 * 1024 * 1024))
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static inline Int sys_futex(Int *futex, Int op, Int val, struct vki_timespec *rel)
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{
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return VG_(do_syscall)(__NR_futex, futex, op, val, rel);
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}
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/* Returns -1 on fail, 0 on wakeup, 1 on pass, 2 on didn't sleep */
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int __futex_down_slow(vg_sema_t *futx, int val, struct vki_timespec *rel)
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{
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Int ret;
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ret = sys_futex(&futx->count, VKI_FUTEX_WAIT, val, rel);
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if (ret == 0) {
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/* <= in case someone else decremented it */
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if (futx->count <= FUTEX_PASSED) {
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futx->count = -1;
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return 1;
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}
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return 0;
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}
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/* EWOULDBLOCK just means value changed before we slept: loop */
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if (ret == -VKI_EWOULDBLOCK)
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return 2;
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return -1;
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}
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int __futex_up_slow(vg_sema_t *futx)
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{
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futx->count = 1;
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__futex_commit();
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return sys_futex(&futx->count, VKI_FUTEX_WAKE, 1, NULL);
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}
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void VGO_(sema_init)(vg_sema_t *sema)
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{
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sema->count = 1;
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__futex_commit();
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}
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#else /* !FUTEX_SEMA */
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/*
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Slower but more portable pipe-based token passing scheme.
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*/
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void VGO_(sema_init)(vg_sema_t *sema)
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{
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VG_(pipe)(sema->pipe);
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sema->pipe[0] = VG_(safe_fd)(sema->pipe[0]);
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sema->pipe[1] = VG_(safe_fd)(sema->pipe[1]);
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sema->owner_thread = -1;
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/* create initial token */
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VG_(write)(sema->pipe[1], "T", 1);
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}
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void VGO_(sema_deinit)(vg_sema_t *sema)
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{
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VG_(close)(sema->pipe[0]);
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VG_(close)(sema->pipe[1]);
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sema->pipe[0] = sema->pipe[1] = -1;
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}
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/* get a token */
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void VGO_(sema_down)(vg_sema_t *sema)
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{
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Char buf[2] = { 'x' };
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Int ret;
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Int lwpid = VG_(gettid)();
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vg_assert(sema->owner_thread != lwpid); /* can't have it already */
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again:
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ret = VG_(read)(sema->pipe[0], buf, 2);
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if (ret == -VKI_EINTR)
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goto again;
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vg_assert(ret == 1); /* should get exactly 1 token */
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vg_assert(buf[0] == 'T');
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sema->owner_thread = lwpid;
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}
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/* put token back */
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void VGO_(sema_up)(vg_sema_t *sema)
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{
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Int ret;
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vg_assert(sema->owner_thread == VG_(gettid)()); /* must have it */
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sema->owner_thread = 0;
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ret = VG_(write)(sema->pipe[1], "T", 1);
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vg_assert(ret == 1);
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}
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#endif /* FUTEX_SEMA */
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/*--------------------------------------------------------------------*/
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/*--- end ---*/
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/*--------------------------------------------------------------------*/
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