From patchwork Mon Jan 21 21:35:27 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathieu Desnoyers X-Patchwork-Id: 1028921 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=sourceware.org (client-ip=209.132.180.131; helo=sourceware.org; envelope-from=libc-alpha-return-99472-incoming=patchwork.ozlabs.org@sourceware.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; secure) header.d=sourceware.org header.i=@sourceware.org header.b="STzhCBs8"; dkim=pass (2048-bit key; unprotected) header.d=efficios.com header.i=@efficios.com header.b="rdwD/gql"; dkim-atps=neutral Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 43k4cJ1bnbz9s55 for ; Tue, 22 Jan 2019 08:36:16 +1100 (AEDT) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:cc:subject:date:message-id; q=dns; s= default; b=KRqgHrSMMzpgkM8cwZIiUxyj2gjxLrLlq0ZNRU1i0o+aUtWgjzwKP VLfLgb3fhZuluppjr61M7dTRln3BaTbOEdHlFPWb3//1QaPZ9y5zIQAXXwJQh68q rzdkE3v6M/9EjuEUtN4NUwnSUzxcdvAe33MSnhyrQ567ix1vgY3WJA= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:cc:subject:date:message-id; s=default; bh=2N4dKuvoJQkFqZnenaQIee6HLsA=; b=STzhCBs8sn915zm5lhLZP3R72p1k cOwHIC2FUCYPZdYWYICe9ohqmZyeDaKRaQ8dQYyFoh8ioufnHrBCUku0MIxu3PBQ 08gfx18ljraSqjxYHsPMEOCdJ2Wc+xZFFYeSQf95/gN/E0/LKWyOW3A8stAlSzOo Kclnt1QeuLmzpyQ= Received: (qmail 121589 invoked by alias); 21 Jan 2019 21:35:50 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 121505 invoked by uid 89); 21 Jan 2019 21:35:49 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-26.9 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, SPF_PASS, TIME_LIMIT_EXCEEDED autolearn=unavailable version=3.3.2 spammy=forbidden, ugly, ben, Application X-HELO: mail.efficios.com DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 1EA88B4FC2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1548106535; bh=ShzuQ5e/jta6qKGHy/xpDxI09XylbeUs3TTiCkgQ9QI=; h=From:To:Date:Message-Id; b=rdwD/gqlLlMCPQKvaH+C6xM5DR8uyOY5KN4qdwEBa/Qr5PVbA+wY4vaJRuGkr2sUw 2/HI5OHSLn+FxHc7to+DdJfMbHAtf0wokTTNnFMl87plWyhXy1oPQmtbYe0lk0+PJi CQLlyiSDsZvuzpOScSmJGCDCtDg3athTNzes6hLrtHpDWwIMVDXBOQOTKi7oPt5wYp vB7U+9+BbH+BQCqnuYCtPzUxgU2i8rM4SsM9X7+SeCtVnr+TprDMcmgH1G2jC6Csx7 brNlrxmR0iHFyurWMT3QO6IX7R0senCrXBqFu5vWWBCldf5E+H7WOWMtr9Ko96l1UT sSHD3YbbM/FQQ== From: Mathieu Desnoyers To: Carlos O'Donell Cc: Florian Weimer , Joseph Myers , Szabolcs Nagy , libc-alpha@sourceware.org, Mathieu Desnoyers , Thomas Gleixner , Ben Maurer , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Will Deacon , Dave Watson , Paul Turner , Rich Felker , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org Subject: [RFC PATCH glibc 1/4] glibc: Perform rseq(2) registration at C startup and thread creation (v6) Date: Mon, 21 Jan 2019 16:35:27 -0500 Message-Id: <20190121213530.23803-1-mathieu.desnoyers@efficios.com> Register rseq(2) TLS for each thread (including main), and unregister for each thread (excluding main). "rseq" stands for Restartable Sequences. See the rseq(2) man page proposed here: https://lkml.org/lkml/2018/9/19/647 This patch is based on glibc commit a502c5294. The rseq(2) system call was merged into Linux 4.18. Signed-off-by: Mathieu Desnoyers CC: Carlos O'Donell CC: Florian Weimer CC: Joseph Myers CC: Szabolcs Nagy CC: Thomas Gleixner CC: Ben Maurer CC: Peter Zijlstra CC: "Paul E. McKenney" CC: Boqun Feng CC: Will Deacon CC: Dave Watson CC: Paul Turner CC: Rich Felker CC: libc-alpha@sourceware.org CC: linux-kernel@vger.kernel.org CC: linux-api@vger.kernel.org --- Changes since v1: - Move __rseq_refcount to an extra field at the end of __rseq_abi to eliminate one symbol. All libraries/programs which try to register rseq (glibc, early-adopter applications, early-adopter libraries) should use the rseq refcount. It becomes part of the ABI within a user-space process, but it's not part of the ABI shared with the kernel per se. - Restructure how this code is organized so glibc keeps building on non-Linux targets. - Use non-weak symbol for __rseq_abi. - Move rseq registration/unregistration implementation into its own nptl/rseq.c compile unit. - Move __rseq_abi symbol under GLIBC_2.29. Changes since v2: - Move __rseq_refcount to its own symbol, which is less ugly than trying to play tricks with the rseq uapi. - Move __rseq_abi from nptl to csu (C start up), so it can be used across glibc, including memory allocator and sched_getcpu(). The __rseq_refcount symbol is kept in nptl, because there is no reason to use it elsewhere in glibc. Changes since v3: - Set __rseq_refcount TLS to 1 on register/set to 0 on unregister because glibc is the first/last user. - Unconditionally register/unregister rseq at thread start/exit, because glibc is the first/last user. - Add missing abilist items. - Rebase on glibc master commit a502c5294. - Add NEWS entry. Changes since v4: - Do not use "weak" symbols for __rseq_abi and __rseq_refcount. Based on "System V Application Binary Interface", weak only affects the link editor, not the dynamic linker. - Install a new sys/rseq.h system header on Linux, which contains the RSEQ_SIG definition, __rseq_abi declaration and __rseq_refcount declaration. Move those definition/declarations from rseq-internal.h to the installed sys/rseq.h header. - Considering that rseq is only available on Linux, move csu/rseq.c to sysdeps/unix/sysv/linux/rseq-sym.c. - Move __rseq_refcount from nptl/rseq.c to sysdeps/unix/sysv/linux/rseq-sym.c, so it is only defined on Linux. - Move both ABI definitions for __rseq_abi and __rseq_refcount to sysdeps/unix/sysv/linux/Versions, so they only appear on Linux. - Document __rseq_abi and __rseq_refcount volatile. - Document the RSEQ_SIG signature define. - Move registration functions from rseq.c to rseq-internal.h static inline functions. Introduce empty stubs in misc/rseq-internal.h, which can be overridden by architecture code in sysdeps/unix/sysv/linux/rseq-internal.h. - Rename __rseq_register_current_thread and __rseq_unregister_current_thread to rseq_register_current_thread and rseq_unregister_current_thread, now that those are only visible as internal static inline functions. - Invoke rseq_register_current_thread() from libc-start.c LIBC_START_MAIN rather than nptl init, so applications not linked against libpthread.so have rseq registered for their main() thread. Note that it is invoked separately for SHARED and !SHARED builds. Changes since v5: - Replace __rseq_refcount by __rseq_lib_abi, which contains two uint32_t: register_state and refcount. The "register_state" field allows inhibiting rseq registration from signal handlers nested on top of glibc registration and occuring after rseq unregistration by glibc. - Introduce enum rseq_register_state, which contains the states allowed for the struct rseq_lib_abi register_state field. --- NEWS | 6 ++ csu/libc-start.c | 12 ++- misc/Makefile | 3 +- misc/rseq-internal.h | 34 +++++++ nptl/pthread_create.c | 9 ++ sysdeps/unix/sysv/linux/Makefile | 5 +- sysdeps/unix/sysv/linux/Versions | 4 + sysdeps/unix/sysv/linux/aarch64/libc.abilist | 2 + sysdeps/unix/sysv/linux/alpha/libc.abilist | 2 + sysdeps/unix/sysv/linux/arm/libc.abilist | 2 + sysdeps/unix/sysv/linux/hppa/libc.abilist | 2 + sysdeps/unix/sysv/linux/i386/libc.abilist | 2 + sysdeps/unix/sysv/linux/ia64/libc.abilist | 2 + .../sysv/linux/m68k/coldfire/libc.abilist | 2 + .../unix/sysv/linux/m68k/m680x0/libc.abilist | 2 + .../unix/sysv/linux/microblaze/libc.abilist | 2 + .../sysv/linux/mips/mips32/fpu/libc.abilist | 2 + .../sysv/linux/mips/mips32/nofpu/libc.abilist | 2 + .../sysv/linux/mips/mips64/n32/libc.abilist | 2 + .../sysv/linux/mips/mips64/n64/libc.abilist | 2 + sysdeps/unix/sysv/linux/nios2/libc.abilist | 2 + .../linux/powerpc/powerpc32/fpu/libc.abilist | 2 + .../powerpc/powerpc32/nofpu/libc.abilist | 2 + .../linux/powerpc/powerpc64/libc-le.abilist | 2 + .../sysv/linux/powerpc/powerpc64/libc.abilist | 2 + .../unix/sysv/linux/riscv/rv64/libc.abilist | 2 + sysdeps/unix/sysv/linux/rseq-internal.h | 91 +++++++++++++++++++ sysdeps/unix/sysv/linux/rseq-sym.c | 54 +++++++++++ .../unix/sysv/linux/s390/s390-32/libc.abilist | 2 + .../unix/sysv/linux/s390/s390-64/libc.abilist | 2 + sysdeps/unix/sysv/linux/sh/libc.abilist | 2 + .../sysv/linux/sparc/sparc32/libc.abilist | 2 + .../sysv/linux/sparc/sparc64/libc.abilist | 2 + sysdeps/unix/sysv/linux/sys/rseq.h | 64 +++++++++++++ .../unix/sysv/linux/x86_64/64/libc.abilist | 2 + .../unix/sysv/linux/x86_64/x32/libc.abilist | 2 + 36 files changed, 328 insertions(+), 6 deletions(-) create mode 100644 misc/rseq-internal.h create mode 100644 sysdeps/unix/sysv/linux/rseq-internal.h create mode 100644 sysdeps/unix/sysv/linux/rseq-sym.c create mode 100644 sysdeps/unix/sysv/linux/sys/rseq.h diff --git a/NEWS b/NEWS index f488821af1..b238eaa391 100644 --- a/NEWS +++ b/NEWS @@ -35,6 +35,12 @@ Major new features: different directory. This is a GNU extension and similar to the Solaris function of the same name. +* Support for automatically registering threads with the Linux rseq(2) + system call has been added. This system call is implemented starting + from Linux 4.18. In order to be activated, it requires that glibc is built + against kernel headers that include this system call, and that glibc + detects availability of that system call at runtime. + Deprecated and removed features, and other changes affecting compatibility: * The glibc.tune tunable namespace has been renamed to glibc.cpu and the diff --git a/csu/libc-start.c b/csu/libc-start.c index 494132368f..dc39e09685 100644 --- a/csu/libc-start.c +++ b/csu/libc-start.c @@ -22,6 +22,7 @@ #include #include #include +#include #include @@ -140,7 +141,10 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL), __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up; -#ifndef SHARED +#ifdef SHARED + /* Register rseq ABI to the kernel. */ + (void) rseq_register_current_thread (); +#else _dl_relocate_static_pie (); char **ev = &argv[argc + 1]; @@ -218,6 +222,9 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL), } # endif + /* Register rseq ABI to the kernel. */ + (void) rseq_register_current_thread (); + /* Initialize libpthread if linked in. */ if (__pthread_initialize_minimal != NULL) __pthread_initialize_minimal (); @@ -230,8 +237,7 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL), # else __pointer_chk_guard_local = pointer_chk_guard; # endif - -#endif /* !SHARED */ +#endif /* Register the destructor of the dynamic linker if there is any. */ if (__glibc_likely (rtld_fini != NULL)) diff --git a/misc/Makefile b/misc/Makefile index c2c9994d17..4175cbb3d3 100644 --- a/misc/Makefile +++ b/misc/Makefile @@ -36,7 +36,8 @@ headers := sys/uio.h bits/uio-ext.h bits/uio_lim.h \ syslog.h sys/syslog.h \ bits/syslog.h bits/syslog-ldbl.h bits/syslog-path.h bits/error.h \ bits/select2.h bits/hwcap.h sys/auxv.h \ - sys/sysmacros.h bits/sysmacros.h bits/types/struct_iovec.h + sys/sysmacros.h bits/sysmacros.h bits/types/struct_iovec.h \ + rseq-internal.h routines := brk sbrk sstk ioctl \ readv writev preadv preadv64 pwritev pwritev64 \ diff --git a/misc/rseq-internal.h b/misc/rseq-internal.h new file mode 100644 index 0000000000..915122e4bf --- /dev/null +++ b/misc/rseq-internal.h @@ -0,0 +1,34 @@ +/* Copyright (C) 2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Mathieu Desnoyers , 2018. + + 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 RSEQ_INTERNAL_H +#define RSEQ_INTERNAL_H + +static inline int +rseq_register_current_thread (void) +{ + return -1; +} + +static inline int +rseq_unregister_current_thread (void) +{ + return -1; +} + +#endif /* rseq-internal.h */ diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c index fe75d04113..bb80f97d2d 100644 --- a/nptl/pthread_create.c +++ b/nptl/pthread_create.c @@ -33,6 +33,7 @@ #include #include #include +#include #include "libioP.h" #include @@ -378,6 +379,7 @@ __free_tcb (struct pthread *pd) START_THREAD_DEFN { struct pthread *pd = START_THREAD_SELF; + bool has_rseq = false; #if HP_TIMING_AVAIL /* Remember the time when the thread was started. */ @@ -396,6 +398,9 @@ START_THREAD_DEFN if (__glibc_unlikely (atomic_exchange_acq (&pd->setxid_futex, 0) == -2)) futex_wake (&pd->setxid_futex, 1, FUTEX_PRIVATE); + /* Register rseq TLS to the kernel. */ + has_rseq = !rseq_register_current_thread (); + #ifdef __NR_set_robust_list # ifndef __ASSUME_SET_ROBUST_LIST if (__set_robust_list_avail >= 0) @@ -573,6 +578,10 @@ START_THREAD_DEFN } #endif + /* Unregister rseq TLS from kernel. */ + if (has_rseq && rseq_unregister_current_thread ()) + abort(); + advise_stack_range (pd->stackblock, pd->stackblock_size, (uintptr_t) pd, pd->guardsize); diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index 72b6b641d5..b18e1cd450 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -1,5 +1,5 @@ ifeq ($(subdir),csu) -sysdep_routines += errno-loc +sysdep_routines += errno-loc rseq-sym endif ifeq ($(subdir),assert) @@ -43,7 +43,8 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ bits/siginfo-arch.h bits/siginfo-consts-arch.h \ bits/procfs.h bits/procfs-id.h bits/procfs-extra.h \ bits/procfs-prregset.h bits/mman-map-flags-generic.h \ - bits/msq-pad.h bits/sem-pad.h bits/shmlba.h bits/shm-pad.h + bits/msq-pad.h bits/sem-pad.h bits/shmlba.h bits/shm-pad.h \ + sys/rseq.h tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \ diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions index 336c13b57d..777ea723f8 100644 --- a/sysdeps/unix/sysv/linux/Versions +++ b/sysdeps/unix/sysv/linux/Versions @@ -171,6 +171,10 @@ libc { mlock2; pkey_alloc; pkey_free; pkey_set; pkey_get; pkey_mprotect; } + GLIBC_2.29 { + __rseq_abi; + __rseq_lib_abi; + } GLIBC_PRIVATE { # functions used in other libraries __syscall_rt_sigqueueinfo; diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist index e66c741d04..8877199b6f 100644 --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist @@ -2138,4 +2138,6 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist index 8df162fe99..0a0db6c29f 100644 --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist @@ -2033,6 +2033,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist index 43c804f9dc..65746b1050 100644 --- a/sysdeps/unix/sysv/linux/arm/libc.abilist +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist @@ -123,6 +123,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist index 88b01c2e75..52c33c08a5 100644 --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist @@ -1880,6 +1880,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist index 6d02f31612..fe4a3e4f83 100644 --- a/sysdeps/unix/sysv/linux/i386/libc.abilist +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist @@ -2045,6 +2045,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist index 4249712611..8db1b3a508 100644 --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist @@ -1914,6 +1914,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist index d47b808862..d2ee6f238f 100644 --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist @@ -124,6 +124,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0x98 diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist index d5e38308be..3250be752f 100644 --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist @@ -1989,6 +1989,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist index 8596b84399..90507bd369 100644 --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist @@ -2130,4 +2130,6 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist index 88e0f896d5..f5ad6e893f 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist @@ -1967,6 +1967,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist index aff7462c34..1549be6a0e 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist @@ -1965,6 +1965,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist index 71d82444aa..33aea43f05 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist @@ -1973,6 +1973,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist index de6c53d293..8a43cbde55 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist @@ -1968,6 +1968,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist index e724bab9fb..7cc6936aa3 100644 --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist @@ -2171,4 +2171,6 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist index e9ecbccb71..aed1d82ebe 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist @@ -1993,6 +1993,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist index da83ea6028..bbd918191c 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist @@ -1997,6 +1997,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist index 4535b40d15..9be7eccefc 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist @@ -2228,4 +2228,6 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist index 65725de4f0..7c2820c28f 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist @@ -123,6 +123,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 _Exit F GLIBC_2.3 _IO_2_1_stderr_ D 0xe0 diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist index bbb3c4a8e7..0dbcc7d565 100644 --- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist +++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist @@ -2100,4 +2100,6 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F diff --git a/sysdeps/unix/sysv/linux/rseq-internal.h b/sysdeps/unix/sysv/linux/rseq-internal.h new file mode 100644 index 0000000000..cb7b2c6f8c --- /dev/null +++ b/sysdeps/unix/sysv/linux/rseq-internal.h @@ -0,0 +1,91 @@ +/* Copyright (C) 2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Mathieu Desnoyers , 2018. + + 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 RSEQ_INTERNAL_H +#define RSEQ_INTERNAL_H + +#include + +#ifdef __NR_rseq + +#include +#include + +static inline int +rseq_register_current_thread (void) +{ + int rc, ret = 0; + INTERNAL_SYSCALL_DECL (err); + + if (__rseq_abi.cpu_id == RSEQ_CPU_ID_REGISTRATION_FAILED) + return -1; + /* Temporarily prevent nested signal handlers from registering rseq. */ + __rseq_lib_abi.register_state = RSEQ_REGISTER_NESTED; + if (__rseq_lib_abi.refcount == UINT_MAX) + { + ret = -1; + goto end; + } + if (__rseq_lib_abi.refcount++) + goto end; + rc = INTERNAL_SYSCALL_CALL (rseq, err, &__rseq_abi, sizeof (struct rseq), + 0, RSEQ_SIG); + if (!rc) + goto end; + if (INTERNAL_SYSCALL_ERRNO (rc, err) != EBUSY) + __rseq_abi.cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED; + ret = -1; +end: + __rseq_lib_abi.register_state = RSEQ_REGISTER_ALLOWED; + return ret; +} + +static inline int +rseq_unregister_current_thread (void) +{ + int rc, ret = 0; + INTERNAL_SYSCALL_DECL (err); + + /* Setting __rseq_register_state = RSEQ_REGISTER_EXITING for the rest of the + thread lifetime. Ensures signal handlers nesting just before thread exit + don't try to register rseq. */ + __rseq_lib_abi.register_state = RSEQ_REGISTER_EXITING; + __rseq_lib_abi.refcount = 0; + rc = INTERNAL_SYSCALL_CALL (rseq, err, &__rseq_abi, sizeof (struct rseq), + RSEQ_FLAG_UNREGISTER, RSEQ_SIG); + if (!rc) + goto end; + ret = -1; +end: + return ret; +} +#else +static inline int +rseq_register_current_thread (void) +{ + return -1; +} + +static inline int +rseq_unregister_current_thread (void) +{ + return -1; +} +#endif + +#endif /* rseq-internal.h */ diff --git a/sysdeps/unix/sysv/linux/rseq-sym.c b/sysdeps/unix/sysv/linux/rseq-sym.c new file mode 100644 index 0000000000..99b277e9d6 --- /dev/null +++ b/sysdeps/unix/sysv/linux/rseq-sym.c @@ -0,0 +1,54 @@ +/* Copyright (C) 2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Mathieu Desnoyers , 2018. + + 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 + . */ + +#include +#include + +#ifdef __NR_rseq +#include +#else + +enum rseq_cpu_id_state { + RSEQ_CPU_ID_UNINITIALIZED = -1, + RSEQ_CPU_ID_REGISTRATION_FAILED = -2, +}; + +/* linux/rseq.h defines struct rseq as aligned on 32 bytes. The kernel ABI + size is 20 bytes. */ +struct rseq { + uint32_t cpu_id_start; + uint32_t cpu_id; + uint64_t rseq_cs; + uint32_t flags; +} __attribute__ ((aligned(4 * sizeof(uint64_t)))); + +struct rseq_lib_abi +{ + uint32_t register_state; + uint32_t refcount; +}; + +#endif + +/* volatile because fields can be read/updated by the kernel. */ +__thread volatile struct rseq __rseq_abi = { + .cpu_id = RSEQ_CPU_ID_UNINITIALIZED, +}; + +/* volatile because fields can be read/updated by signal handlers. */ +__thread volatile struct rseq_lib_abi __rseq_lib_abi; diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist index e85ac2a178..eff957032a 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist @@ -2002,6 +2002,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist index d56931022c..32bfb25c1f 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist @@ -1908,6 +1908,8 @@ GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F GLIBC_2.29 __fentry__ F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist index ff939a15c4..a12d738d86 100644 --- a/sysdeps/unix/sysv/linux/sh/libc.abilist +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist @@ -1884,6 +1884,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist index 64fa9e10a5..3333634dfa 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist @@ -1996,6 +1996,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist index db909d1506..02db9f6669 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist @@ -1937,6 +1937,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/sys/rseq.h b/sysdeps/unix/sysv/linux/sys/rseq.h new file mode 100644 index 0000000000..61937fb193 --- /dev/null +++ b/sysdeps/unix/sysv/linux/sys/rseq.h @@ -0,0 +1,64 @@ +/* Copyright (C) 2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Mathieu Desnoyers , 2019. + + 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 _SYS_RSEQ_H +#define _SYS_RSEQ_H 1 + +/* We use the structures declarations from the kernel headers. */ +#include +#include + +/* Signature required before each abort handler code. */ +#define RSEQ_SIG 0x53053053 + +enum rseq_register_state +{ + /* Value RSEQ_REGISTER_ALLOWED means it is allowed to update + the refcount field and to register/unregister rseq. */ + RSEQ_REGISTER_ALLOWED = 0, + /* Value RSEQ_REGISTER_NESTED means it is temporarily forbidden + to update the refcount field or to register/unregister rseq. */ + RSEQ_REGISTER_NESTED = 1, + /* Value RSEQ_REGISTER_EXITING means it is forbidden to update the + refcount field or to register/unregister rseq for the rest of the + thread's lifetime. */ + RSEQ_REGISTER_EXITING = 2, +}; + +struct rseq_lib_abi +{ + uint32_t register_state; /* enum rseq_register_state. */ + /* The refcount field keeps track of rseq users, so early adopters + of rseq can cooperate amongst each other and with glibc to + share rseq thread registration. The refcount field can only be + updated when allowed by the value of field register_state. + Registering rseq should be performed when incrementing refcount + from 0 to 1, and unregistering rseq should be performed when + decrementing refcount from 1 to 0. */ + uint32_t refcount; +}; + +/* volatile because fields can be read/updated by the kernel. */ +extern __thread volatile struct rseq __rseq_abi +__attribute__ ((tls_model ("initial-exec"))); + +/* volatile because fields can be read/updated by signal handlers. */ +extern __thread volatile struct rseq_lib_abi __rseq_lib_abi +__attribute__ ((tls_model ("initial-exec"))); + +#endif /* sys/rseq.h */ diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist index 3b175f104b..417d8ab9a6 100644 --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist @@ -1895,6 +1895,8 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist index 1b57710477..ef5ad4160d 100644 --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist @@ -2146,4 +2146,6 @@ GLIBC_2.28 thrd_current F GLIBC_2.28 thrd_equal F GLIBC_2.28 thrd_sleep F GLIBC_2.28 thrd_yield F +GLIBC_2.29 __rseq_abi T 0x20 +GLIBC_2.29 __rseq_lib_abi T 0x8 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F