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In <https://sourceware.org/ml/libc-alpha/2013-12/msg00008.html>, Aurelien noted issues with the definition of __ASSUME_ACCEPT4, which I discussed in more detail in <https://sourceware.org/ml/libc-alpha/2013-12/msg00014.html>; these are now bug 16609. As previously noted, __ASSUME_ACCEPT4 is used in two ways: * In OS-independent code, to mean "accept4 can be assumed to work rather than fail with ENOSYS". It doesn't matter whether it's implemented with socketcall or a separate syscall. * In Linux-specific code, to mean "the socketcall multiplex syscall can be assumed to handle the accept4 operation. When used in Linux-specific code, it *never* refers to anything relating to the accept4 syscall, only to the socketcall multiplexer. This patch splits the macro into separate __ASSUME_ACCEPT4_SOCKETCALL, __ASSUME_ACCEPT4_SYSCALL and __ASSUME_ACCEPT4 to clarify the different cases involved. A macro __ASSUME_SOCKETCALL is added for convenience in writing logic relating to all socketcall architectures. In addition, to address the issue of architectures where socketcall support for accept4 was added before a separate syscall was added (and so the separate syscall should not be used unless known to be present or fallback to socketcall is available), a fourth macro __ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL is added to indicate that the syscall became available at the same time as socketcall support. This is then used in the relevant places in a conditional determining whether to undefine __NR_accept4 (the simple approach to avoiding the syscall's presence causing problems; I didn't try to implement runtime fallback from the syscall to socketcall). Architecture-specific note: alpha defined __ASSUME_ACCEPT4 for 2.6.33 and later, but actually the syscall was added for alpha in 3.2, so this patch uses the correct condition for __ASSUME_ACCEPT4_SYSCALL there. Tested x86_64, including that disassembly of the installed shared libraries is unchanged by this patch. [BZ #16609] * sysdeps/unix/sysv/linux/kernel-features.h [__i386__ || __powerpc__ || __s390__ || __sh__ || __sparc__] (__ASSUME_SOCKETCALL): Define. [__LINUX_KERNEL_VERSION && __ASSUME_SOCKETCALL] (__ASSUME_ACCEPT4_SOCKETCALL): Likewise. [(__LINUX_KERNEL_VERSION >= 0x02061c && (__x86_64__ || __sparc__)) || (__LINUX_KERNEL_VERSION >= 0x020625 && (__powerpc__ || __sh__))] (__ASSUME_ACCEPT4_SYSCALL): Likewise. [__sparc__] (__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL): Likewise. [__ASSUME_ACCEPT4_SOCKETCALL || __ASSUME_ACCEPT4_SYSCALL] (__ASSUME_ACCEPT4): Define instead of using previous [__LINUX_KERNEL_VERSION >= 0x02061c && (__i386__ || __x86_64__ || __powerpc__ || __sparc__ || __s390__)] condition. * sysdeps/unix/sysv/linux/aarch64/kernel-features.h (__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL. * sysdeps/unix/sysv/linux/accept4.c [__ASSUME_SOCKETCALL && !__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL && !__ASSUME_ACCEPT4_SYSCALL] (__NR_accept4): Undefine. [!__ASSUME_ACCEPT4]: Change condition to [!__ASSUME_ACCEPT4_SOCKETCALL]. * sysdeps/unix/sysv/linux/alpha/kernel-features.h (__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL. Correct condition to [__LINUX_KERNEL_VERSION >= 0x030200]. * sysdeps/unix/sysv/linux/arm/kernel-features.h [__LINUX_KERNEL_VERSION >= 0x020624] (__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL. * sysdeps/unix/sysv/linux/i386/accept4.S [__ASSUME_ACCEPT4]: Change conditions to [__ASSUME_ACCEPT4_SOCKETCALL]. * sysdeps/unix/sysv/linux/ia64/kernel-features.h [__LINUX_KERNEL_VERSION >= 0x030300] (__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL. * sysdeps/unix/sysv/linux/internal_accept4.S [__ASSUME_SOCKETCALL && !__ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL && !__ASSUME_ACCEPT4_SYSCALL] (__NR_accept4): Undefine. [__ASSUME_ACCEPT4]: Change condition to [__ASSUME_ACCEPT4_SOCKETCALL]. * sysdeps/unix/sysv/linux/m68k/kernel-features.h (__ASSUME_SOCKETCALL): Define. [__LINUX_KERNEL_VERSION >= 0x02061c] (__ASSUME_ACCEPT4): Remove. * sysdeps/unix/sysv/linux/microblaze/kernel-features.h (__ASSUME_SOCKETCALL): Define. (__ASSUME_ACCEPT4): Remove. [__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_ACCEPT4_SYSCALL): Define. * sysdeps/unix/sysv/linux/mips/kernel-features.h [__LINUX_KERNEL_VERSION >= 0x02061f] (__ASSUME_ACCEPT4_SYSCALL): Likewise. * sysdeps/unix/sysv/linux/tile/kernel-features.h (__ASSUME_ACCEPT4): Change to __ASSUME_ACCEPT4_SYSCALL. * sysdeps/unix/sysv/linux/hppa/kernel-features.h [__LINUX_KERNEL_VERSION >= 0x020622] (__ASSUME_ACCEPT4_SYSCALL): Define.
106 lines
3.0 KiB
C
106 lines
3.0 KiB
C
/* Copyright (C) 2008-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2008.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but 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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <signal.h>
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#include <sys/socket.h>
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#include <sysdep-cancel.h>
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#include <sys/syscall.h>
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#include <kernel-features.h>
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/* Do not use the accept4 syscall on socketcall architectures unless
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it was added at the same time as the socketcall support or can be
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assumed to be present. */
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#if defined __ASSUME_SOCKETCALL \
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&& !defined __ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL \
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&& !defined __ASSUME_ACCEPT4_SYSCALL
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# undef __NR_accept4
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#endif
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#ifdef __NR_accept4
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int
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accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
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{
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if (SINGLE_THREAD_P)
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return INLINE_SYSCALL (accept4, 4, fd, addr.__sockaddr__, addr_len, flags);
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int oldtype = LIBC_CANCEL_ASYNC ();
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int result = INLINE_SYSCALL (accept4, 4, fd, addr.__sockaddr__, addr_len,
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flags);
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LIBC_CANCEL_RESET (oldtype);
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return result;
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}
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#elif defined __NR_socketcall
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# ifndef __ASSUME_ACCEPT4_SOCKETCALL
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extern int __internal_accept4 (int fd, __SOCKADDR_ARG addr,
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socklen_t *addr_len, int flags)
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attribute_hidden;
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static int have_accept4;
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int
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accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
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{
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if (__glibc_likely (have_accept4 >= 0))
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{
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int ret = __internal_accept4 (fd, addr, addr_len, flags);
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/* The kernel returns -EINVAL for unknown socket operations.
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We need to convert that error to an ENOSYS error. */
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if (__builtin_expect (ret < 0, 0)
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&& have_accept4 == 0
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&& errno == EINVAL)
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{
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/* Try another call, this time with the FLAGS parameter
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cleared and an invalid file descriptor. This call will not
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cause any harm and it will return immediately. */
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ret = __internal_accept4 (-1, addr, addr_len, 0);
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if (errno == EINVAL)
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{
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have_accept4 = -1;
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__set_errno (ENOSYS);
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}
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else
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{
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have_accept4 = 1;
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__set_errno (EINVAL);
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}
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return -1;
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}
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return ret;
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}
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__set_errno (ENOSYS);
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return -1;
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}
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# else
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/* When __ASSUME_ACCEPT4_SOCKETCALL accept4 is defined in
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internal_accept4.S. */
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# endif
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#else
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int
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accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
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{
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__set_errno (ENOSYS);
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return -1;
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}
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stub_warning (accept4)
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#endif
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