cosmopolitan/libc/calls/read-nt.c
Justine Tunney 9c0821def7
Make stdin pollable on Windows
You can now play Super Mario Bros in CMD.EXE using Cosmopolitan! This is
thanks to a new worker thread that's spawned on Windows whenever any one
of poll(), select(), or ioctl(FIONREAD) is linked.
2023-08-13 22:42:25 -07:00

209 lines
8 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/sig.internal.h"
#include "libc/calls/struct/fd.internal.h"
#include "libc/calls/struct/iovec.h"
#include "libc/calls/struct/iovec.internal.h"
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/calls/wincrash.internal.h"
#include "libc/errno.h"
#include "libc/intrin/strace.internal.h"
#include "libc/macros.internal.h"
#include "libc/nt/enum/filetype.h"
#include "libc/nt/enum/wait.h"
#include "libc/nt/errors.h"
#include "libc/nt/events.h"
#include "libc/nt/files.h"
#include "libc/nt/ipc.h"
#include "libc/nt/runtime.h"
#include "libc/nt/struct/overlapped.h"
#include "libc/nt/synchronization.h"
#include "libc/nt/thread.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/errfuns.h"
static textwindows void sys_read_nt_abort(int64_t handle,
struct NtOverlapped *overlapped) {
unassert(CancelIoEx(handle, overlapped) ||
GetLastError() == kNtErrorNotFound);
}
static textwindows void MungeTerminalInput(struct Fd *fd, char *p, size_t n) {
if (!(fd->ttymagic & kFdTtyNoCr2Nl)) {
size_t i;
for (i = 0; i < n; ++i) {
if (p[i] == '\r') {
p[i] = '\n';
}
}
}
}
// Manual CMD.EXE echoing for when !ICANON && ECHO is the case.
static textwindows void EchoTerminalInput(struct Fd *fd, char *p, size_t n) {
int64_t hOutput;
if (fd->kind == kFdConsole) {
hOutput = fd->extra;
} else {
hOutput = g_fds.p[1].handle;
}
if (fd->ttymagic & kFdTtyEchoRaw) {
WriteFile(hOutput, p, n, 0, 0);
} else {
size_t i;
for (i = 0; i < n; ++i) {
if (isascii(p[i]) && iscntrl(p[i]) && p[i] != '\n' && p[i] != '\t') {
char ctl[2];
ctl[0] = '^';
ctl[1] = p[i] ^ 0100;
WriteFile(hOutput, ctl, 2, 0, 0);
} else {
WriteFile(hOutput, p + i, 1, 0, 0);
}
}
}
}
static textwindows ssize_t sys_read_nt_impl(struct Fd *fd, void *data,
size_t size, int64_t offset) {
// perform the read i/o operation
bool32 ok;
uint32_t got;
int filetype;
int64_t handle;
int abort_errno = EAGAIN;
size = MIN(size, 0x7ffff000);
handle = __resolve_stdin_handle(fd->handle);
filetype = GetFileType(handle);
if (filetype == kNtFileTypeChar || filetype == kNtFileTypePipe) {
struct NtOverlapped overlap = {0};
if (offset != -1) {
// pread() and pwrite() should not be called on a pipe or tty
return espipe();
}
if ((overlap.hEvent = CreateEvent(0, 0, 0, 0))) {
// the win32 manual says it's important to *not* put &got here
// since for overlapped i/o, we always use GetOverlappedResult
ok = ReadFile(handle, data, size, 0, &overlap);
if (!ok && GetLastError() == kNtErrorIoPending) {
// i/o operation is in flight; blocking is unavoidable
// if we're in non-blocking mode, then immediately abort
// if an interrupt is pending, then abort before waiting
// otherwise wait for i/o periodically checking interrupts
if (fd->flags & O_NONBLOCK) {
sys_read_nt_abort(handle, &overlap);
} else if (_check_interrupts(kSigOpRestartable, g_fds.p)) {
Interrupted:
abort_errno = errno;
sys_read_nt_abort(handle, &overlap);
} else {
for (;;) {
uint32_t i;
i = WaitForSingleObject(overlap.hEvent, __SIG_POLLING_INTERVAL_MS);
if (i == kNtWaitTimeout) {
if (_check_interrupts(kSigOpRestartable, g_fds.p)) {
goto Interrupted;
}
} else {
npassert(!i);
break;
}
}
}
ok = true;
}
if (ok) {
// overlapped is allocated on stack, so it's important we wait
// for windows to acknowledge that it's done using that memory
ok = GetOverlappedResult(handle, &overlap, &got, true);
}
CloseHandle(overlap.hEvent);
} else {
ok = false;
}
} else if (offset == -1) {
// perform simple blocking file read
ok = ReadFile(handle, data, size, &got, 0);
} else {
// perform pread()-style file read at particular file offset
int64_t position;
// save file pointer which windows clobbers, even for overlapped i/o
if (!SetFilePointerEx(handle, 0, &position, SEEK_CUR)) {
return __winerr(); // fd probably isn't seekable?
}
struct NtOverlapped overlap = {0};
overlap.Pointer = (void *)(uintptr_t)offset;
ok = ReadFile(handle, data, size, 0, &overlap);
if (!ok && GetLastError() == kNtErrorIoPending) ok = true;
if (ok) ok = GetOverlappedResult(handle, &overlap, &got, true);
// restore file pointer which windows clobbers, even on error
unassert(SetFilePointerEx(handle, position, 0, SEEK_SET));
}
if (ok) {
if (fd->ttymagic & kFdTtyMunging) {
MungeTerminalInput(fd, data, got);
}
if (fd->ttymagic & kFdTtyEchoing) {
EchoTerminalInput(fd, data, got);
}
return got;
}
switch (GetLastError()) {
case kNtErrorBrokenPipe: // broken pipe
case kNtErrorNoData: // closing named pipe
case kNtErrorHandleEof: // pread read past EOF
return 0; //
case kNtErrorAccessDenied: // read doesn't return EACCESS
return ebadf(); //
case kNtErrorOperationAborted:
errno = abort_errno;
return -1;
default:
return __winerr();
}
}
textwindows ssize_t sys_read_nt(struct Fd *fd, const struct iovec *iov,
size_t iovlen, int64_t opt_offset) {
ssize_t rc;
uint32_t size;
size_t i, total;
if (opt_offset < -1) return einval();
if (_check_interrupts(kSigOpRestartable, fd)) return -1;
while (iovlen && !iov[0].iov_len) iov++, iovlen--;
if (iovlen) {
for (total = i = 0; i < iovlen; ++i) {
if (!iov[i].iov_len) continue;
rc = sys_read_nt_impl(fd, iov[i].iov_base, iov[i].iov_len, opt_offset);
if (rc == -1) return -1;
total += rc;
if (opt_offset != -1) opt_offset += rc;
if (rc < iov[i].iov_len) break;
}
return total;
} else {
return sys_read_nt_impl(fd, NULL, 0, opt_offset);
}
}