mirror of
https://github.com/jart/cosmopolitan.git
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c7a8cd21e9
This change improves copy_file_range(), sendfile(), splice(), openpty(), closefrom(), close_range(), fadvise() and posix_fadvise() in addition to writing tests that confirm things like errno and seeking behavior across platforms. We now less aggressively polyfill behavior with some of these functions when the platform support isn't available. Please see: https://justine.lol/cosmopolitan/functions.html
62 lines
3.1 KiB
C
62 lines
3.1 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 2022 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/calls.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/limits.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Closes extra file descriptors, e.g.
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*
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* // close all non-stdio file descriptors
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* if (closefrom(3) == -1) {
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* for (int i = 3; i < 256; ++i) {
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* close(i);
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* }
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* }
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*
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* @return 0 on success, or -1 w/ errno
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* @error EBADF if `first` is negative
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* @error EBADF on OpenBSD if `first` is greater than highest fd
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* @error EINVAL if flags are bad or first is greater than last
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* @error EMFILE if a weird race condition happens on Linux
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* @error ENOSYS if not Linux 5.9+, FreeBSD 8+, or OpenBSD
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* @error EINTR possibly on OpenBSD
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* @error ENOMEM on Linux maybe
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*/
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int closefrom(int first) {
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int rc, err;
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if (IsNetbsd() || IsWindows() || IsMetal()) {
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rc = enosys();
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} else if (first < 0) {
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// consistent with openbsd
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// freebsd allows this but it's dangerous
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// necessary on linux due to type signature
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rc = ebadf();
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} else if (IsLinux()) {
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rc = sys_close_range(first, 0xffffffffu, 0);
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} else {
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rc = sys_closefrom(first);
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}
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STRACE("closefrom(%d) → %d% m", first, rc);
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return rc;
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}
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