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https://github.com/jart/cosmopolitan.git
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dc0ea6640e
This change makes further effort towards improving our poll() implementation on the New Technology. The stdin worker didn't work out so well for Python so it's not being used for now. System call tracing with the --strace flag should now be less noisy now on Windows unless you modify the strace.internal.h defines to turn on some optional ones that are most useful for debugging the system call wrappers.
123 lines
4.5 KiB
C
123 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/bits/weaken.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/strace.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/intrin/asan.internal.h"
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#include "libc/macros.internal.h"
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#include "libc/sysv/consts/iov.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/zipos/zipos.internal.h"
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#define __NR_pwritev_linux 0x0128
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/**
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* Writes data from multiple buffers to offset.
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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 pwrite().
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*
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* @return number of bytes actually sent, or -1 w/ errno
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* @asyncsignalsafe
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* @vforksafe
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*/
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ssize_t pwritev(int fd, const struct iovec *iov, int iovlen, int64_t off) {
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static bool once, demodernize;
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int i, err;
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ssize_t rc;
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size_t sent, toto;
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if (fd < 0) return einval();
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if (iovlen < 0) return einval();
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if (IsAsan() && !__asan_is_valid_iov(iov, iovlen)) return efault();
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if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
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return weaken(__zipos_write)(
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(struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle, iov, iovlen, off);
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} else if (IsWindows()) {
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if (fd < g_fds.n) {
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return sys_write_nt(fd, iov, iovlen, off);
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} else {
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return ebadf();
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}
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} else if (IsMetal()) {
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return enosys();
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}
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if (iovlen == 1) {
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return sys_pwrite(fd, iov[0].iov_base, iov[0].iov_len, off, off);
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}
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/*
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* NT, 2018-era 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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err = errno;
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rc = sys_pwritev(fd, iov, iovlen, off, off);
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if (rc == -1 && errno == ENOSYS) {
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errno = err;
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once = true;
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demodernize = true;
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STRACE("demodernizing %s() due to %s", "pwritev", "ENOSYS");
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} else if (IsLinux() && rc == __NR_pwritev_linux) {
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if (__iovec_size(iov, iovlen) < __NR_pwritev_linux) {
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demodernize = true;
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STRACE("demodernizing %s() due to %s", "pwritev",
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"RHEL5:CVE-2010-3301");
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once = true;
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} else {
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return rc;
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}
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} else {
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once = true;
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return rc;
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}
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}
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if (!demodernize) {
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return sys_pwritev(fd, iov, iovlen, off, off);
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}
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if (!iovlen) {
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return sys_pwrite(fd, NULL, 0, off, off);
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}
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for (toto = i = 0; i < iovlen; ++i) {
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rc = sys_pwrite(fd, iov[i].iov_base, iov[i].iov_len, off, off);
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if (rc == -1) {
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if (toto && (errno == EINTR || errno == EAGAIN)) {
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return toto;
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} else {
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return -1;
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}
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}
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sent = rc;
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toto += sent;
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if (sent != iov[i].iov_len) {
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break;
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}
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}
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return toto;
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}
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