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/calls/directmap-nt.c

@@ -18,18 +18,21 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/assert.h"
 #include "libc/calls/internal.h"
+#include "libc/intrin/kprintf.h"
 #include "libc/nt/enum/filemapflags.h"
 #include "libc/nt/enum/pageflags.h"
 #include "libc/nt/memory.h"
+#include "libc/nt/process.h"
 #include "libc/nt/runtime.h"
+#include "libc/nt/struct/processmemorycounters.h"
 #include "libc/runtime/directmap.internal.h"
+#include "libc/runtime/runtime.h"
 #include "libc/sysv/consts/map.h"
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/consts/prot.h"
 
-textwindows noasan struct DirectMap sys_mmap_nt(void *addr, size_t size,
-                                                int prot, int flags, int fd,
-                                                int64_t off) {
+textwindows struct DirectMap sys_mmap_nt(void *addr, size_t size, int prot,
+                                         int flags, int fd, int64_t off) {
   size_t i;
   bool iscow;
   int64_t handle;
@@ -38,6 +41,18 @@ textwindows noasan struct DirectMap sys_mmap_nt(void *addr, size_t size,
   struct ProtectNt fl;
   const struct NtSecurityAttributes *sec;
 
+#ifndef NDEBUG
+  struct NtProcessMemoryCountersEx memcount = {
+      .cb = sizeof(struct NtProcessMemoryCountersEx),
+  };
+  if (GetProcessMemoryInfo(GetCurrentProcess(), &memcount, sizeof(memcount))) {
+    if (memcount.PeakWorkingSetSize > 5ull * 1024 * 1024 * 1024) {
+      kprintf("error: exceeded 5gb memory limit%n");
+      _Exit(201);
+    }
+  }
+#endif
+
   if (fd != -1) {
     handle = g_fds.p[fd].handle;
   } else {