Fix bugs with recent change

This change makes further effort towards improving our poll()
implementation on the New Technology. The stdin worker didn't work out
so well for Python so it's not being used for now. System call tracing
with the --strace flag should now be less noisy now on Windows unless
you modify the strace.internal.h defines to turn on some optional ones
that are most useful for debugging the system call wrappers.

libc/runtime/fork-nt.c

@@ -52,6 +52,7 @@
 STATIC_YOINK("_check_sigchld");
 
 extern int __pid;
+extern int64_t __wincrashearly;
 extern unsigned long long __kbirth;
 extern unsigned char __data_start[]; /* αpε */
 extern unsigned char __data_end[];   /* αpε */
@@ -59,6 +60,11 @@ extern unsigned char __bss_start[];  /* αpε */
 extern unsigned char __bss_end[];    /* αpε */
 bool32 __onntconsoleevent_nt(uint32_t);
 
+static textwindows wontreturn void KillForkChild(const char *func) {
+  STRACE("fork() %s() failed %d", func, GetLastError());
+  ExitProcess(177);
+}
+
 static textwindows char16_t *ParseInt(char16_t *p, int64_t *x) {
   *x = 0;
   while (*p == ' ') p++;
@@ -84,7 +90,7 @@ static inline textwindows ssize_t ForkIo(int64_t h, char *p, size_t n,
 static dontinline textwindows bool ForkIo2(int64_t h, void *buf, size_t n,
                                            bool32 (*fn)(), const char *sf) {
   ssize_t rc = ForkIo(h, buf, n, fn);
-  // STRACE("%s(%ld, %'zu) → %'zd% m", sf, h, n, rc);
+  NTTRACE("%s(%ld, %'zu) → %'zd% m", sf, h, n, rc);
   return rc != -1;
 }
 
@@ -92,8 +98,10 @@ static dontinline textwindows bool WriteAll(int64_t h, void *buf, size_t n) {
   return ForkIo2(h, buf, n, WriteFile, "WriteFile");
 }
 
-static textwindows dontinline bool ReadAll(int64_t h, void *buf, size_t n) {
-  return ForkIo2(h, buf, n, ReadFile, "ReadFile");
+static textwindows dontinline void ReadOrDie(int64_t h, void *buf, size_t n) {
+  if (!ForkIo2(h, buf, n, ReadFile, "ReadFile")) {
+    KillForkChild("ReadFile");
+  }
 }
 
 textwindows void WinMainForked(void) {
@@ -114,7 +122,7 @@ textwindows void WinMainForked(void) {
   // this variable should have the pipe handle numba
   varlen = GetEnvironmentVariable(u"_FORK", fvar, ARRAYLEN(fvar));
   if (!varlen || varlen >= ARRAYLEN(fvar)) return;
-  STRACE("WinMainForked()");
+  NTTRACE("WinMainForked()");
   SetEnvironmentVariable(u"_FORK", NULL);
   ParseInt(fvar, &reader);
 
@@ -123,21 +131,21 @@ textwindows void WinMainForked(void) {
   // this is stored in a special secretive memory map!
   // read ExtendMemoryIntervals for further details :|
   maps = (void *)kMemtrackStart;
-  ReadAll(reader, jb, sizeof(jb));
-  ReadAll(reader, &mapcount, sizeof(_mmi.i));
-  ReadAll(reader, &mapcapacity, sizeof(_mmi.n));
+  ReadOrDie(reader, jb, sizeof(jb));
+  ReadOrDie(reader, &mapcount, sizeof(_mmi.i));
+  ReadOrDie(reader, &mapcapacity, sizeof(_mmi.n));
   specialz = ROUNDUP(mapcapacity * sizeof(_mmi.p[0]), kMemtrackGran);
   MapViewOfFileEx(
       CreateFileMapping(-1, 0, kNtPageReadwrite, specialz >> 32, specialz, 0),
       kNtFileMapWrite, 0, 0, specialz, maps);
-  ReadAll(reader, maps, mapcount * sizeof(_mmi.p[0]));
+  ReadOrDie(reader, maps, mapcount * sizeof(_mmi.p[0]));
   if (IsAsan()) {
     shad = (char *)(((intptr_t)maps >> 3) + 0x7fff8000);
     size = ROUNDUP(specialz >> 3, FRAMESIZE);
     MapViewOfFileEx(
         CreateFileMapping(-1, 0, kNtPageReadwrite, size >> 32, size, 0),
         kNtFileMapWrite, 0, 0, size, maps);
-    ReadAll(reader, shad, (mapcount * sizeof(_mmi.p[0])) >> 3);
+    ReadOrDie(reader, shad, (mapcount * sizeof(_mmi.p[0])) >> 3);
   }
 
   // read the heap mappings from the parent process
@@ -152,7 +160,7 @@ textwindows void WinMainForked(void) {
                                     upsize >> 32, upsize, 0);
       MapViewOfFileEx(maps[i].h, kNtFileMapWrite | kNtFileMapExecute, 0, 0,
                       upsize, addr);
-      ReadAll(reader, addr, size);
+      ReadOrDie(reader, addr, size);
     } else {
       // we can however safely inherit MAP_SHARED with zero copy
       MapViewOfFileEx(maps[i].h,
@@ -167,8 +175,8 @@ textwindows void WinMainForked(void) {
   savepid = __pid;
   savebir = __kbirth;
   savetsc = ts;
-  ReadAll(reader, __data_start, __data_end - __data_start);
-  ReadAll(reader, __bss_start, __bss_end - __bss_start);
+  ReadOrDie(reader, __data_start, __data_end - __data_start);
+  ReadOrDie(reader, __bss_start, __bss_end - __bss_start);
   __pid = savepid;
   __kbirth = savebir;
   ts = savetsc;
@@ -177,23 +185,28 @@ textwindows void WinMainForked(void) {
   _mmi.p = maps;
   _mmi.n = specialz / sizeof(_mmi.p[0]);
   for (i = 0; i < mapcount; ++i) {
-    VirtualProtect((void *)((uint64_t)maps[i].x << 16), maps[i].size,
-                   __prot2nt(maps[i].prot, maps[i].iscow), &oldprot);
+    if (!VirtualProtect((void *)((uint64_t)maps[i].x << 16), maps[i].size,
+                        __prot2nt(maps[i].prot, maps[i].iscow), &oldprot)) {
+      KillForkChild("VirtualProtect");
+    }
   }
 
   // mitosis complete
-  CloseHandle(reader);
+  if (!CloseHandle(reader)) {
+    KillForkChild("CloseHandle");
+  }
 
   // rewrap the stdin named pipe hack
   // since the handles closed on fork
   if (weaken(ForkNtStdinWorker)) weaken(ForkNtStdinWorker)();
   struct Fds *fds = VEIL("r", &g_fds);
-  fds->__init_p[0].handle = GetStdHandle(kNtStdInputHandle);   // just in case
-  fds->__init_p[1].handle = GetStdHandle(kNtStdOutputHandle);  // just in case
-  fds->__init_p[2].handle = GetStdHandle(kNtStdErrorHandle);   // just in case
+  fds->__init_p[0].handle = GetStdHandle(kNtStdInputHandle);
+  fds->__init_p[1].handle = GetStdHandle(kNtStdOutputHandle);
+  fds->__init_p[2].handle = GetStdHandle(kNtStdErrorHandle);
 
   // restore the crash reporting stuff
   if (weaken(__wincrash_nt)) {
+    RemoveVectoredExceptionHandler(__wincrashearly);
     AddVectoredExceptionHandler(1, (void *)weaken(__wincrash_nt));
   }
   if (weaken(__onntconsoleevent_nt)) {