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https://github.com/jart/cosmopolitan.git
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87a6669900
This change makes send() / sendto() always block on Windows. It's needed because poll(POLLOUT) doesn't guarantee a socket is immediately writable on Windows, and it caused rsync to fail because it made that assumption. The only exception is when a SO_SNDTIMEO is specified which will EAGAIN. Tests are added confirming MSG_WAITALL and MSG_NOSIGNAL work as expected on all our supported OSes. Most of the platform-specific MSG_FOO magnums have been deleted, with the exception of MSG_FASTOPEN. Your --strace log will now show MSG_FOO flags as symbols rather than numbers. I've also removed cv_wait_example_test because it's 0.3% flaky with Qemu under system load since it depends on a process being readily scheduled.
96 lines
4.8 KiB
C
96 lines
4.8 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/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/dce.h"
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#include "libc/intrin/describeflags.h"
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#include "libc/intrin/strace.h"
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#include "libc/sock/internal.h"
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#include "libc/sock/sock.h"
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#include "libc/sock/syscall_fd.internal.h"
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#include "libc/sysv/consts/msg.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Receives data from network socket.
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*
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* Calling `recv(fd, p, n, 0)` is equivalent to `read(fd, p, n)`.
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*
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* Unlike files where the OS tries very hard to fulfill the entire
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* requested `size` before returning, read operations on sockets aim to
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* return as quickly as possible. For example, if 10 bytes are requested
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* and a packet comes in with only 5 bytes, then recv() will most likely
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* return those 5 bytes before waiting longer. The `MSG_WAITALL` flag
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* may be passed when waiting longer is desired. In that case, short
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* reads should only be possible when the connection status changes or
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* the receive operation is interrupted by a signal.
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*
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* @param fd is the file descriptor returned by socket()
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* @param buf is where received network data gets copied
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* @param size is the byte capacity of buf
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* @param flags can have `MSG_OOB`, `MSG_PEEK`, `MSG_DONTWAIT`, `MSG_WAITALL`
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* @return number of bytes received, 0 on remote close, or -1 w/ errno
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* @raise EINTR if signal handler was called instead
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* @raise EINVAL if unknown bits were passed in `flags`
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* @raise EINVAL if flag isn't supported by host operating system
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* @raise EINVAL if `MSG_WAITALL` and `MSG_PEEK` were both passed
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* @raise EBADF if `fd` is an invalid file descriptor
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* @raise EAGAIN if `MSG_DONTWAIT` was passed and no data was available
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* @raise EAGAIN if `O_NONBLOCK` is in play and no data was available
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* @error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable),
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* EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.
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* @cancelationpoint
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* @asyncsignalsafe
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* @restartable (unless SO_RCVTIMEO on Linux or Windows)
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*/
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ssize_t recv(int fd, void *buf, size_t size, int flags) {
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ssize_t rc;
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BEGIN_CANCELATION_POINT;
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if ((flags & (MSG_WAITALL | MSG_PEEK)) == (MSG_WAITALL | MSG_PEEK)) {
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// this is possible on some OSes like Linux but it breaks FreeBSD
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// and Windows will raise EOPNOTSUPP when it gets passed together
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return einval();
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} else if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
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rc = enotsock();
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} else if (!IsWindows()) {
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rc = sys_recvfrom(fd, buf, size, flags, 0, 0);
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} else if (__isfdopen(fd)) {
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if (__isfdkind(fd, kFdSocket)) {
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rc = sys_recv_nt(fd, (struct iovec[]){{buf, size}}, 1, flags);
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} else if (__isfdkind(fd, kFdFile)) {
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if (flags) {
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rc = einval();
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} else {
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rc = sys_read_nt(fd, (struct iovec[]){{buf, size}}, 1, -1);
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}
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} else {
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rc = enotsock();
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}
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} else {
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rc = ebadf();
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}
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END_CANCELATION_POINT;
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DATATRACE("recv(%d, [%#.*hhs%s], %'zu, %s) → %'ld% lm", fd,
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MAX(0, MIN(40, rc)), buf, rc > 40 ? "..." : "", size,
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DescribeMsg(flags), rc);
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return rc;
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}
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