8495e8b1e9
(or loading a dso linked to libthr.so into process which was not linked against threading library). - Remove libthr interposers of the libc functions, including __error(). Instead, functions calls are indirected through the interposing table, similar to how pthread stubs in libc are already done. Libc by default points either to syscall trampolines or to existing libc implementations. On libthr load, libthr rewrites the pointers to the cancellable implementations already in libthr. The interposition table is separate from pthreads stubs indirection table to not pull pthreads stubs into static binaries. - Postpone the malloc(3) internal mutexes initialization until libthr is loaded. This avoids recursion between calloc(3) and static pthread_mutex_t initialization. - Reinstall signal handlers with wrapper on libthr load. The _rtld_is_dlopened(3) is used to avoid useless calls to sigaction(2) when libthr is statically referenced from the main binary. In the process, fix openat(2), swapcontext(2) and setcontext(2) interposing. The libc symbols were exported at different versions than libthr interposers. Export both libc and libthr versions from libc now, with default set to the higher version from libthr. Remove unused and disconnected swapcontext(3) userspace implementation from libc/gen. No objections from: deischen Tested by: pho, antoine (exp-run) (previous versions) Sponsored by: The FreeBSD Foundation MFC after: 1 week
261 lines
7.6 KiB
C
261 lines
7.6 KiB
C
/*
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* Copyright (c) 2005 David Xu <davidxu@freebsd.org>
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* Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#include <sys/syscall.h>
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#include "namespace.h"
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#include <errno.h>
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#include <link.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <pthread.h>
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#include <spinlock.h>
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#include "un-namespace.h"
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#include "libc_private.h"
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#include "rtld_lock.h"
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#include "thr_private.h"
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__weak_reference(_pthread_atfork, pthread_atfork);
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int
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_pthread_atfork(void (*prepare)(void), void (*parent)(void),
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void (*child)(void))
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{
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struct pthread *curthread;
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struct pthread_atfork *af;
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_thr_check_init();
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if ((af = malloc(sizeof(struct pthread_atfork))) == NULL)
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return (ENOMEM);
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curthread = _get_curthread();
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af->prepare = prepare;
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af->parent = parent;
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af->child = child;
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THR_CRITICAL_ENTER(curthread);
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_thr_rwl_wrlock(&_thr_atfork_lock);
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TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe);
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_thr_rwl_unlock(&_thr_atfork_lock);
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THR_CRITICAL_LEAVE(curthread);
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return (0);
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}
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void
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__pthread_cxa_finalize(struct dl_phdr_info *phdr_info)
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{
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atfork_head temp_list = TAILQ_HEAD_INITIALIZER(temp_list);
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struct pthread *curthread;
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struct pthread_atfork *af, *af1;
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_thr_check_init();
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curthread = _get_curthread();
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THR_CRITICAL_ENTER(curthread);
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_thr_rwl_wrlock(&_thr_atfork_lock);
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TAILQ_FOREACH_SAFE(af, &_thr_atfork_list, qe, af1) {
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if (__elf_phdr_match_addr(phdr_info, af->prepare) ||
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__elf_phdr_match_addr(phdr_info, af->parent) ||
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__elf_phdr_match_addr(phdr_info, af->child)) {
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TAILQ_REMOVE(&_thr_atfork_list, af, qe);
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TAILQ_INSERT_TAIL(&temp_list, af, qe);
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}
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}
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_thr_rwl_unlock(&_thr_atfork_lock);
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THR_CRITICAL_LEAVE(curthread);
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while ((af = TAILQ_FIRST(&temp_list)) != NULL) {
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TAILQ_REMOVE(&temp_list, af, qe);
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free(af);
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}
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_thr_tsd_unload(phdr_info);
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_thr_sigact_unload(phdr_info);
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}
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__weak_reference(__thr_fork, _fork);
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pid_t
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__thr_fork(void)
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{
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struct pthread *curthread;
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struct pthread_atfork *af;
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pid_t ret;
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int errsave, cancelsave;
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int was_threaded;
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int rtld_locks[MAX_RTLD_LOCKS];
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if (!_thr_is_inited())
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return (__sys_fork());
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curthread = _get_curthread();
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cancelsave = curthread->no_cancel;
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curthread->no_cancel = 1;
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_thr_rwl_rdlock(&_thr_atfork_lock);
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/* Run down atfork prepare handlers. */
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TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) {
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if (af->prepare != NULL)
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af->prepare();
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}
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/*
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* Block all signals until we reach a safe point.
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*/
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_thr_signal_block(curthread);
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_thr_signal_prefork();
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/*
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* All bets are off as to what should happen soon if the parent
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* process was not so kindly as to set up pthread fork hooks to
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* relinquish all running threads.
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*/
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if (_thr_isthreaded() != 0) {
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was_threaded = 1;
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_malloc_prefork();
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_rtld_atfork_pre(rtld_locks);
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} else {
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was_threaded = 0;
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}
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/*
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* Fork a new process.
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* There is no easy way to pre-resolve the __sys_fork symbol
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* without performing the fork. Use the syscall(2)
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* indirection, the syscall symbol is resolved in
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* _thr_rtld_init() with side-effect free call.
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*/
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ret = syscall(SYS_fork);
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if (ret == 0) {
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/* Child process */
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errsave = errno;
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curthread->cancel_pending = 0;
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curthread->flags &= ~(THR_FLAGS_NEED_SUSPEND|THR_FLAGS_DETACHED);
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/*
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* Thread list will be reinitialized, and later we call
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* _libpthread_init(), it will add us back to list.
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*/
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curthread->tlflags &= ~TLFLAGS_IN_TDLIST;
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/* child is a new kernel thread. */
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thr_self(&curthread->tid);
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/* clear other threads locked us. */
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_thr_umutex_init(&curthread->lock);
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_mutex_fork(curthread);
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_thr_signal_postfork_child();
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if (was_threaded)
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_rtld_atfork_post(rtld_locks);
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_thr_setthreaded(0);
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/* reinitalize library. */
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_libpthread_init(curthread);
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/* atfork is reinitializeded by _libpthread_init()! */
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_thr_rwl_rdlock(&_thr_atfork_lock);
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if (was_threaded) {
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__isthreaded = 1;
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_malloc_postfork();
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__isthreaded = 0;
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}
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/* Ready to continue, unblock signals. */
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_thr_signal_unblock(curthread);
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/* Run down atfork child handlers. */
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TAILQ_FOREACH(af, &_thr_atfork_list, qe) {
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if (af->child != NULL)
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af->child();
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}
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_thr_rwlock_unlock(&_thr_atfork_lock);
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curthread->no_cancel = cancelsave;
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} else {
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/* Parent process */
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errsave = errno;
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_thr_signal_postfork();
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if (was_threaded) {
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_rtld_atfork_post(rtld_locks);
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_malloc_postfork();
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}
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/* Ready to continue, unblock signals. */
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_thr_signal_unblock(curthread);
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/* Run down atfork parent handlers. */
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TAILQ_FOREACH(af, &_thr_atfork_list, qe) {
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if (af->parent != NULL)
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af->parent();
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}
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_thr_rwlock_unlock(&_thr_atfork_lock);
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curthread->no_cancel = cancelsave;
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/* test async cancel */
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if (curthread->cancel_async)
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_thr_testcancel(curthread);
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}
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errno = errsave;
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return (ret);
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}
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