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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.
57 lines
2.9 KiB
C
57 lines
2.9 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 2021 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/syscall-sysv.internal.h"
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#include "libc/calls/syscall_support-nt.internal.h"
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#include "libc/calls/termios.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/nt/files.h"
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#include "libc/sysv/errfuns.h"
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static textwindows int sys_tcdrain_nt(int fd) {
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if (!__isfdopen(fd)) return ebadf();
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if (!FlushFileBuffers(g_fds.p[fd].handle)) return __winerr();
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return 0;
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}
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/**
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* Waits until all written output is transmitted.
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*
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* @param fd is file descriptor of tty
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* @raise EBADF if `fd` isn't an open file descriptor
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* @raise ENOTTY if `fd` is open but not a teletypewriter
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* @raise EIO if process group of writer is orphoned, calling thread is
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* not blocking `SIGTTOU`, and process isn't ignoring `SIGTTOU`
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* @raise ENOSYS on bare metal
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* @cancellationpoint
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* @asyncsignalsafe
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*/
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int tcdrain(int fd) {
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int rc;
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if (IsMetal()) {
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rc = enosys();
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} else if (!IsWindows()) {
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rc = sys_ioctl_cp(fd, TCSBRK, (void *)(intptr_t)1);
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} else {
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rc = sys_tcdrain_nt(fd);
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}
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STRACE("tcdrain(%d) → %d% m", fd, rc);
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return rc;
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}
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