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https://github.com/jart/cosmopolitan.git
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9e3e985ae5
Here's some screenshots of an emulator tui program that was compiled on Linux, then scp'd it to Windows, Mac, and FreeBSD. https://justine.storage.googleapis.com/blinkenlights-cmdexe.png https://justine.storage.googleapis.com/blinkenlights-imac.png https://justine.storage.googleapis.com/blinkenlights-freebsd.png https://justine.storage.googleapis.com/blinkenlights-lisp.png How is this even possible that we have a nontrivial ui binary that just works on Mac, Windows, Linux, and BSD? Surely a first ever achievement. Fixed many bugs. Bootstrapped John McCarthy's metacircular evaluator on bare metal in half the size of Altair BASIC (about 2.5kb) and ran it in emulator for fun and profit.
77 lines
3.5 KiB
C
77 lines
3.5 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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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/bits/bits.h"
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#include "libc/bits/safemacros.h"
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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/struct/iovec.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/sysv/consts/iov.h"
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#include "libc/sysv/errfuns.h"
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#define __NR_preadv_linux 0x0127
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/**
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* Reads data from multiple buffers from file descriptor at offset.
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*
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* @param count is recommended to be 16 or fewer; if it exceeds IOV_MAX
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* then the extra buffers are simply ignored
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* @return number of bytes actually read, or -1 w/ errno
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*/
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ssize_t preadv(int fd, struct iovec *iovec, int count, int64_t off) {
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static bool once, demodernize;
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int olderr;
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ssize_t rc;
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if (!count) return 0;
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if ((count = min(count, IOV_MAX)) < 0) return einval();
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/*
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* NT, XNU, and 2007-era Linux don't support this system call.
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*/
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if (!once) {
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once = true;
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if (IsModeDbg() || (IsLinux() && iovec->iov_len >= __NR_preadv_linux)) {
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/*
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* Read size is too large to detect older kernels safely without
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* introducing nontrivial mechanics. We'll try again later.
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*/
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once = false;
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demodernize = true;
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} else {
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olderr = errno;
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rc = preadv$sysv(fd, iovec, count, off);
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if (rc == -1 && errno == ENOSYS) {
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errno = olderr;
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demodernize = true;
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} else if (IsLinux() && rc == __NR_preadv_linux /*RHEL5:CVE-2010-3301*/) {
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demodernize = true;
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} else {
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return rc;
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}
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}
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}
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if (!demodernize) {
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return preadv$sysv(fd, iovec, count, off);
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} else {
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return pread(fd, iovec[0].iov_base, iovec[0].iov_len, off);
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}
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}
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