Date: Fri, 20 Nov 2009 19:19:51 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r199606 - in head/lib/libc: gen include Message-ID: <200911201919.nAKJJpdu053858@svn.freebsd.org>
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Author: jhb Date: Fri Nov 20 19:19:51 2009 New Revision: 199606 URL: http://svn.freebsd.org/changeset/base/199606 Log: Add an internal _once() method. This works identical to pthread_once(3) with the additional property that it is safe for routines in libc to use in both single-threaded and multi-threaded processes. Multi-threaded processes use the pthread_once() implementation from the threading library while single-threaded processes use a simplified "stub" version internal to libc. The libc stub-version of pthread_once() now also uses the simplified "stub" version as well instead of being a nop. Reviewed by: deischen, Matthew Fleming @ Isilon Suggested by: alc MFC after: 1 week Added: head/lib/libc/gen/_once_stub.c (contents, props changed) Modified: head/lib/libc/gen/Makefile.inc head/lib/libc/gen/_pthread_stubs.c head/lib/libc/include/libc_private.h Modified: head/lib/libc/gen/Makefile.inc ============================================================================== --- head/lib/libc/gen/Makefile.inc Fri Nov 20 19:01:09 2009 (r199605) +++ head/lib/libc/gen/Makefile.inc Fri Nov 20 19:19:51 2009 (r199606) @@ -5,7 +5,8 @@ .PATH: ${.CURDIR}/${MACHINE_ARCH}/gen ${.CURDIR}/gen SRCS+= __getosreldate.c __xuname.c \ - _pthread_stubs.c _rand48.c _spinlock_stub.c _thread_init.c \ + _once_stub.c _pthread_stubs.c _rand48.c _spinlock_stub.c \ + _thread_init.c \ alarm.c arc4random.c assert.c basename.c check_utility_compat.c \ clock.c closedir.c confstr.c \ crypt.c ctermid.c daemon.c devname.c dirname.c disklabel.c \ Added: head/lib/libc/gen/_once_stub.c ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/lib/libc/gen/_once_stub.c Fri Nov 20 19:19:51 2009 (r199606) @@ -0,0 +1,67 @@ +/*- + * Copyright (c) 2009 Advanced Computing Technologies LLC + * Written by: John H. Baldwin <jhb@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "namespace.h" +#include <pthread.h> +#include "un-namespace.h" +#include "libc_private.h" + +/* + * This implements pthread_once() for the single-threaded case. It is + * non-static so that it can be used by _pthread_stubs.c. + */ +int +_libc_once(pthread_once_t *once_control, void (*init_routine)(void)) +{ + + if (once_control->state == PTHREAD_DONE_INIT) + return (0); + init_routine(); + once_control->state = PTHREAD_DONE_INIT; + return (0); +} + +/* + * This is the internal interface provided to libc. It will use + * pthread_once() from the threading library in a multi-threaded + * process and _libc_once() for a single-threaded library. Because + * _libc_once() uses the same ABI for the values in the pthread_once_t + * structure as the threading library, it is safe for a process to + * switch from _libc_once() to pthread_once() when threading is + * enabled. + */ +int +_once(pthread_once_t *once_control, void (*init_routine)(void)) +{ + + if (__isthreaded) + return (_pthread_once(once_control, init_routine)); + return (_libc_once(once_control, init_routine)); +} Modified: head/lib/libc/gen/_pthread_stubs.c ============================================================================== --- head/lib/libc/gen/_pthread_stubs.c Fri Nov 20 19:01:09 2009 (r199605) +++ head/lib/libc/gen/_pthread_stubs.c Fri Nov 20 19:19:51 2009 (r199606) @@ -105,7 +105,7 @@ pthread_func_entry_t __thr_jtable[PJT_MA {PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEX_LOCK */ {PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEX_TRYLOCK */ {PJT_DUAL_ENTRY(stub_zero)}, /* PJT_MUTEX_UNLOCK */ - {PJT_DUAL_ENTRY(stub_zero)}, /* PJT_ONCE */ + {PJT_DUAL_ENTRY(_libc_once)}, /* PJT_ONCE */ {PJT_DUAL_ENTRY(stub_zero)}, /* PJT_RWLOCK_DESTROY */ {PJT_DUAL_ENTRY(stub_zero)}, /* PJT_RWLOCK_INIT */ {PJT_DUAL_ENTRY(stub_zero)}, /* PJT_RWLOCK_RDLOCK */ Modified: head/lib/libc/include/libc_private.h ============================================================================== --- head/lib/libc/include/libc_private.h Fri Nov 20 19:01:09 2009 (r199605) +++ head/lib/libc/include/libc_private.h Fri Nov 20 19:19:51 2009 (r199606) @@ -34,6 +34,7 @@ #ifndef _LIBC_PRIVATE_H_ #define _LIBC_PRIVATE_H_ +#include <sys/_pthreadtypes.h> /* * This global flag is non-zero when a process has created one @@ -147,6 +148,13 @@ int _yp_check(char **); void _init_tls(void); /* + * Provides pthread_once()-like functionality for both single-threaded + * and multi-threaded applications. + */ +int _once(pthread_once_t *, void (*)(void)); +int _libc_once(pthread_once_t *, void (*)(void)); + +/* * Set the TLS thread pointer */ void _set_tp(void *tp);
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