mirror of
https://github.com/jart/cosmopolitan.git
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126 lines
4.5 KiB
C
126 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/intrin/bits.h"
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#include "libc/intrin/likely.h"
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#include "libc/intrin/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/state.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/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/asan.internal.h"
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#include "libc/intrin/describeflags.internal.h"
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#include "libc/intrin/kprintf.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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static ssize_t Preadv(int fd, 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 got, 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_read)(
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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_read_nt(g_fds.p + 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_pread(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 (!__vforked && !once) {
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err = errno;
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rc = sys_preadv(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", "preadv", "ENOSYS");
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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_preadv(fd, iov, iovlen, off, off);
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}
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if (!iovlen) {
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return sys_pread(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_pread(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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got = rc;
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toto += got;
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if (got != 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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/**
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* Reads with maximum generality.
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*
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* @return number of bytes actually read, or -1 w/ errno
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* @asyncsignalsafe
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* @vforksafe
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*/
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ssize_t preadv(int fd, struct iovec *iov, int iovlen, int64_t off) {
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ssize_t rc;
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rc = Preadv(fd, iov, iovlen, off);
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#if defined(SYSDEBUG) && _DATATRACE
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if (UNLIKELY(__strace > 0)) {
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kprintf(STRACE_PROLOGUE "preadv(%d, [", fd);
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DescribeIov(iov, iovlen, rc != -1 ? rc : 0);
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kprintf("], %d, %'ld) → %'ld% m\n", iovlen, off, rc);
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}
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#endif
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return rc;
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}
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