Improve synchronization

- Fix bugs in kDos2Errno definition
- malloc() should now be thread safe
- Fix bug in rollup.com header generator
- Fix open(O_APPEND) on the New Technology
- Fix select() on the New Technology and test it
- Work towards refactoring i/o for thread safety
- Socket reads and writes on NT now poll for signals
- Work towards i/o completion ports on the New Technology
- Make read() and write() intermittently check for signals
- Blinkenlights keyboard i/o so much better on NT w/ poll()
- You can now poll() files and sockets at the same time on NT
- Fix bug in appendr() that manifests with dlmalloc footers off

libc/sock/send-nt.c

@@ -0,0 +1,89 @@
+/*-*- 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/strace.internal.h"
+#include "libc/nt/enum/wait.h"
+#include "libc/nt/errors.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/yoink.inc"
+#include "libc/sysv/consts/fileno.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Performs stream socket send on the New Technology.
+ *
+ * @param fd must be a socket
+ * @return number of bytes handed off, or -1 w/ errno
+ */
+textwindows ssize_t sys_send_nt(int fd, const struct iovec *iov, size_t iovlen,
+                                uint32_t flags) {
+  ssize_t rc;
+  uint32_t i, sent = 0;
+  struct NtIovec iovnt[16];
+  struct NtOverlapped overlapped = {.hEvent = WSACreateEvent()};
+
+  if (_check_interrupts(true, g_fds.p)) return eintr();
+
+  if (!WSASend(g_fds.p[fd].handle, iovnt, __iovec2nt(iovnt, iov, iovlen), &sent,
+               flags, &overlapped, NULL)) {
+    rc = sent;
+    goto Finished;
+  }
+
+  if (WSAGetLastError() != kNtErrorIoPending) {
+    STRACE("WSASend failed %lm");
+    rc = __winsockerr();
+    goto Finished;
+  }
+
+  for (;;) {
+    i = WSAWaitForMultipleEvents(1, &overlapped.hEvent, true,
+                                 __SIG_POLLING_INTERVAL_MS, true);
+    if (i == kNtWaitFailed) {
+      STRACE("WSAWaitForMultipleEvents failed %lm");
+      rc = __winsockerr();
+      goto Finished;
+    } else if (i == kNtWaitTimeout) {
+      if (_check_interrupts(true, g_fds.p)) {
+        rc = eintr();
+        goto Finished;
+      }
+    } else if (i == kNtWaitIoCompletion) {
+      STRACE("IOCP TRIGGERED EINTR");
+    } else {
+      break;
+    }
+  }
+
+  if (!WSAGetOverlappedResult(g_fds.p[fd].handle, &overlapped, &sent, false,
+                              &flags)) {
+    STRACE("WSAGetOverlappedResult failed %lm");
+    rc = __winsockerr();
+    goto Finished;
+  }
+
+  rc = sent;
+Finished:
+  WSACloseEvent(overlapped.hEvent);
+  return rc;
+}