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https://github.com/jart/cosmopolitan.git
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2278327eba
This change makes some miracle modifications to the System Five system call support, which lets us have safe, correct, and atomic handling of thread cancellations. It all turned out to be cheaper than anticipated because it wasn't necessary to modify the system call veneers. We were able to encode the cancellability of each system call into the magnums found in libc/sysv/syscalls.sh. Since cancellations are so waq, we are also supporting a lovely Musl Libc mask feature for raising ECANCELED.
94 lines
4.5 KiB
C
94 lines
4.5 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/internal.h"
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#include "libc/calls/struct/iovec.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/asan.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/nt/winsock.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/struct/sockaddr.h"
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#include "libc/sock/struct/sockaddr.internal.h"
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#include "libc/sock/syscall_fd.internal.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Receives data from network.
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*
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* This function blocks unless MSG_DONTWAIT is passed.
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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_{WAITALL,DONTROUTE,PEEK,OOB}, etc.
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* @param opt_out_srcaddr receives the binary ip:port of the data's origin
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* @param opt_inout_srcaddrsize is srcaddr capacity which gets updated
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* @return number of bytes received, 0 on remote close, or -1 w/ errno
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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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* @cancellationpoint
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* @asyncsignalsafe
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* @restartable (unless SO_RCVTIMEO)
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*/
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ssize_t recvfrom(int fd, void *buf, size_t size, int flags,
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struct sockaddr *opt_out_srcaddr,
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uint32_t *opt_inout_srcaddrsize) {
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ssize_t rc;
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uint32_t sz;
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union sockaddr_storage_bsd bsd;
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if (IsAsan() &&
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(!__asan_is_valid(buf, size) ||
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(opt_out_srcaddr &&
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(!__asan_is_valid(opt_inout_srcaddrsize,
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sizeof(*opt_inout_srcaddrsize)) ||
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!__asan_is_valid(opt_out_srcaddr, *opt_inout_srcaddrsize))))) {
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rc = efault();
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} else if (!IsWindows()) {
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if (!IsBsd() || !opt_out_srcaddr) {
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rc = sys_recvfrom(fd, buf, size, flags, opt_out_srcaddr,
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opt_inout_srcaddrsize);
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} else {
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sz = sizeof(bsd);
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if ((rc = sys_recvfrom(fd, buf, size, flags, &bsd, &sz)) != -1) {
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sockaddr2linux(&bsd, sz, (void *)opt_out_srcaddr,
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opt_inout_srcaddrsize);
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}
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}
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} else if (__isfdopen(fd)) {
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if (__isfdkind(fd, kFdSocket)) {
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rc = sys_recvfrom_nt(&g_fds.p[fd], (struct iovec[]){{buf, size}}, 1,
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flags, opt_out_srcaddr, opt_inout_srcaddrsize);
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} else if (__isfdkind(fd, kFdFile) && !opt_out_srcaddr) { /* socketpair */
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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(&g_fds.p[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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DATATRACE("recvfrom(%d, [%#.*hhs%s], %'zu, %#x) → %'ld% lm", fd,
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MAX(0, MIN(40, rc)), buf, rc > 40 ? "..." : "", size, flags, rc);
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return rc;
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}
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