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https://github.com/jart/cosmopolitan.git
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3f49889841
- Fix preadv() and pwritev() for old distros - Introduce _npassert() and _unassert() macros - Prove that file locks work properly on Windows - Support fcntl(F_DUPFD_CLOEXEC) on more systems
63 lines
3.3 KiB
C
63 lines
3.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/syscall-nt.internal.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/sysv/consts/o.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Duplicates file descriptor/handle.
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*
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* On Windows, we can't guarantee the desired file descriptor is used.
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* We can however remap the standard handles (non-atomically) if their
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* symbolic names are used.
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*
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* @param oldfd isn't closed afterwards
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* @param newfd if already assigned, is silently closed beforehand;
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* unless it's equal to oldfd, in which case dup2() is a no-op
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* @param flags may have O_CLOEXEC which is needed to preserve the
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* close-on-execve() state after file descriptor duplication
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* @return newfd on success, or -1 w/ errno
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* @raise EINVAL if flags has unsupported bits
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* @raise EINVAL if newfd equals oldfd
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* @raise EBADF is oldfd isn't open
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* @raise EBADF is newfd negative or too big
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* @raise EINTR if a signal handler was called
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* @see dup(), dup2()
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*/
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int dup3(int oldfd, int newfd, int flags) {
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int rc;
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if (oldfd == newfd || (flags & ~O_CLOEXEC)) {
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rc = einval(); // NetBSD doesn't do this
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} else if (oldfd < 0 || newfd < 0) {
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rc = ebadf();
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} else if (__isfdkind(oldfd, kFdZip)) {
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rc = eopnotsupp();
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} else if (!IsWindows()) {
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rc = sys_dup3(oldfd, newfd, flags);
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} else {
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rc = sys_dup_nt(oldfd, newfd, flags, -1);
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}
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STRACE("dup3(%d, %d, %d) → %d% m", oldfd, newfd, flags, rc);
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return rc;
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}
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