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
96 lines
4.5 KiB
C
96 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/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/fmt/itoa.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/describeflags.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/mem/alloca.h"
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#include "libc/str/str.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/thread/thread.h"
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static struct Splice {
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pthread_once_t once;
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bool ok;
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} g_splice;
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static bool HasSplice(void) {
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bool ok;
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int e, rc;
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e = errno;
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if (IsLinux()) {
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// Our testing indicates splice() doesn't work as documneted on
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// RHEL5 and RHEL7 so let's require a modern kernel to be safe.
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// We choose close_range() for this since it's listed by pledge
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ok = sys_close_range(-1, -2, 0) == -1 && errno == EINVAL;
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} else {
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ok = false;
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}
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errno = e;
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return ok;
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}
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static void splice_init(void) {
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g_splice.ok = HasSplice();
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}
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/**
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* Transfers data to/from pipe.
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*
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* @param flags can have SPLICE_F_{MOVE,NONBLOCK,MORE,GIFT}
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* @param opt_in_out_inoffset may be specified if `infd` isn't a pipe and is
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* used as both an input and output parameter for pread() behavior
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* @param opt_in_out_outoffset may be specified if `outfd` isn't a pipe and is
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* used as both an input and output parameter for pwrite() behavior
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* @return number of bytes transferred, 0 on input end, or -1 w/ errno
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* @raise EBADF if `infd` or `outfd` aren't open files or append-only
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* @raise ESPIPE if an offset arg was specified for a pipe fd
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* @raise EINVAL if offset was given for non-seekable device
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* @raise EINVAL if file system doesn't support splice()
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* @raise EFAULT if one of the pointers memory is bad
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* @raise EINVAL if `flags` is invalid
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* @raise ENOSYS if not Linux 5.9+
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* @see copy_file_range() for file ↔ file
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* @see sendfile() for seekable → socket
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*/
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ssize_t splice(int infd, int64_t *opt_in_out_inoffset, int outfd,
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int64_t *opt_in_out_outoffset, size_t uptobytes,
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uint32_t flags) {
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ssize_t rc;
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pthread_once(&g_splice.once, splice_init);
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if (!g_splice.ok) {
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rc = enosys();
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} else if (IsAsan() && ((opt_in_out_inoffset &&
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!__asan_is_valid(opt_in_out_inoffset, 8)) ||
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(opt_in_out_outoffset &&
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!__asan_is_valid(opt_in_out_outoffset, 8)))) {
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rc = efault();
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} else {
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rc = sys_splice(infd, opt_in_out_inoffset, outfd, opt_in_out_outoffset,
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uptobytes, flags);
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}
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STRACE("splice(%d, %s, %d, %s, %'zu, %#x) → %'ld% m", infd,
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DescribeInOutInt64(rc, opt_in_out_inoffset), outfd,
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DescribeInOutInt64(rc, opt_in_out_outoffset), uptobytes, flags);
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return rc;
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}
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