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https://github.com/jart/cosmopolitan.git
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ccbae7799e
This change also found a few POSIX compliance bugs with errnos. Another bug was discovered where, on Windows, pread() and pwrite() could modify the file position in cases where ReadFile() returned an error e.g. when seeking past the end of file. We also have more tests!
73 lines
3.6 KiB
C
73 lines
3.6 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/internal.h"
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#include "libc/calls/struct/iovec.h"
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#include "libc/calls/struct/iovec.internal.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/intrin/asan.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/intrin/weaken.h"
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#include "libc/sock/internal.h"
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#include "libc/sock/sock.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/zipos/zipos.internal.h"
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/**
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* Reads data from file descriptor.
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*
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* This function changes the current file position. For documentation
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* on file position behaviors and gotchas, see the lseek() function.
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*
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* @param fd is something open()'d earlier
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* @param buf is copied into, cf. copy_file_range(), sendfile(), etc.
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* @param size in range [1..0x7ffff000] is reasonable
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* @return [1..size] bytes on success, 0 on EOF, or -1 w/ errno; with
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* exception of size==0, in which case return zero means no error
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* @see write(), pread(), readv()
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* @asyncsignalsafe
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* @restartable
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* @vforksafe
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*/
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ssize_t read(int fd, void *buf, size_t size) {
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ssize_t rc;
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if (fd >= 0) {
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if (IsAsan() && !__asan_is_valid(buf, size)) {
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rc = efault();
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} else if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
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rc = _weaken(__zipos_read)(
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(struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle,
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&(struct iovec){buf, size}, 1, -1);
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} else if (!IsWindows() && !IsMetal()) {
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rc = sys_read(fd, buf, size);
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} else if (fd >= g_fds.n) {
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rc = ebadf();
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} else if (IsMetal()) {
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rc = sys_readv_metal(g_fds.p + fd, &(struct iovec){buf, size}, 1);
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} else {
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rc = sys_readv_nt(g_fds.p + fd, &(struct iovec){buf, size}, 1);
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}
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} else {
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rc = einval();
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}
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DATATRACE("read(%d, [%#.*hhs%s], %'zu) → %'zd% m", fd, MAX(0, MIN(40, rc)),
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buf, rc > 40 ? "..." : "", size, rc);
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return rc;
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}
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