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e16a7d8f3b
`et` means `expandtab`. ```sh rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\) :vi/vi: \1 xoet\2:vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2 :vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/' ```
84 lines
4 KiB
C
84 lines
4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et 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/cp.internal.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/struct/iovec.internal.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/errno.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/describeflags.internal.h"
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#include "libc/intrin/likely.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/intrin/weaken.h"
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#include "libc/sock/internal.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Writes data from multiple buffers.
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*
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* This is the same thing as write() except it has multiple buffers.
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* This yields a performance boost in situations where it'd be expensive
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* to stitch data together using memcpy() or issuing multiple syscalls.
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* This wrapper is implemented so that writev() calls where iovlen<2 may
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* be passed to the kernel as write() instead. This yields a 100 cycle
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* performance boost in the case of a single small iovec.
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*
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* Please note that it's not an error for a short write to happen. This
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* can happen in the kernel if EINTR happens after some of the write has
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* been committed. It can also happen if we need to polyfill this system
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* call using write().
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*
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* @return number of bytes actually handed off, or -1 w/ errno
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* @cancelationpoint
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* @restartable
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*/
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ssize_t writev(int fd, const struct iovec *iov, int iovlen) {
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ssize_t rc;
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BEGIN_CANCELATION_POINT;
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if (fd < 0) {
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rc = ebadf();
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} else if (iovlen < 0) {
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rc = einval();
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} else if (IsAsan() && !__asan_is_valid_iov(iov, iovlen)) {
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rc = efault();
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} else if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
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rc = ebadf(); // posix specifies this when not open()'d for writing
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} else if (IsLinux() || IsXnu() || IsFreebsd() || IsOpenbsd() || IsNetbsd()) {
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if (iovlen == 1) {
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rc = sys_write(fd, iov[0].iov_base, iov[0].iov_len);
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} else {
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rc = sys_writev(fd, iov, iovlen);
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}
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} else if (fd >= g_fds.n) {
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rc = ebadf();
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} else if (IsMetal()) {
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rc = sys_writev_metal(g_fds.p + fd, iov, iovlen);
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} else if (IsWindows()) {
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rc = sys_writev_nt(fd, iov, iovlen);
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} else {
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rc = enosys();
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}
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END_CANCELATION_POINT;
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STRACE("writev(%d, %s, %d) → %'ld% m", fd,
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DescribeIovec(rc != -1 ? rc : -2, iov, iovlen), iovlen, rc);
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return rc;
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}
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