Fix more things

- Update a couple unicode data files
- Disable strace during logger calls
- SQLite now uses pread() / pwrite()
- pread() past EOF on NT now returns 0
- Make the NT mmap() and fork() code elegant
- Give NT a big performance boost with memory
- Add many more mmap() tests to prove it works

libc/calls/unlinkat-nt.c

@@ -18,7 +18,11 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/internal.h"
 #include "libc/errno.h"
+#include "libc/nt/createfile.h"
+#include "libc/nt/enum/accessmask.h"
+#include "libc/nt/enum/creationdisposition.h"
 #include "libc/nt/enum/fileflagandattributes.h"
+#include "libc/nt/enum/filesharemode.h"
 #include "libc/nt/enum/io.h"
 #include "libc/nt/errors.h"
 #include "libc/nt/files.h"
@@ -28,6 +32,48 @@
 #include "libc/nt/synchronization.h"
 #include "libc/sysv/consts/at.h"
 
+/**
+ * Performs synchronization on directory of pathname.
+ *
+ * This code is intended to help prevent subsequent i/o operations
+ * from failing for no reason at all. For example a unit test that
+ * repeatedly opens and unlinks the same filename.
+ */
+static textwindows int SyncDirectory(int df, char16_t path[PATH_MAX], int n) {
+  int rc;
+  int64_t fh;
+  char16_t *p;
+  if ((p = memrchr16(path, '\\', n))) {
+    if (p - path == 2 && path[1] == ':') return 0;  // XXX: avoid syncing volume
+    *p = 0;
+  } else {
+    if (df != AT_FDCWD) {
+      if (FlushFileBuffers(df)) {
+        return 0;
+      } else {
+        return __winerr();
+      }
+    }
+    path[0] = '.';
+    path[1] = 0;
+  }
+  if ((fh = CreateFile(
+           path, kNtFileGenericWrite,
+           kNtFileShareRead | kNtFileShareWrite | kNtFileShareDelete, 0,
+           kNtOpenExisting, kNtFileAttributeNormal | kNtFileFlagBackupSemantics,
+           0)) != -1) {
+    if (FlushFileBuffers(fh)) {
+      rc = 0;
+    } else {
+      rc = __winerr();
+    }
+    CloseHandle(fh);
+  } else {
+    rc = __winerr();
+  }
+  return rc;
+}
+
 static textwindows bool IsDirectorySymlink(const char16_t *path) {
   int64_t h;
   struct NtWin32FindData data;
@@ -67,16 +113,28 @@ static textwindows int sys_rmdir_nt(const char16_t *path) {
 }
 
 static textwindows int sys_unlink_nt(const char16_t *path) {
-  if (IsDirectorySymlink(path)) return sys_rmdir_nt(path);
-  return DeleteFile(path) ? 0 : __winerr();
+  if (IsDirectorySymlink(path)) {
+    return sys_rmdir_nt(path);
+  } else if (DeleteFile(path)) {
+    return 0;
+  } else {
+    return __winerr();
+  }
 }
 
 textwindows int sys_unlinkat_nt(int dirfd, const char *path, int flags) {
-  uint16_t path16[PATH_MAX];
-  if (__mkntpathat(dirfd, path, 0, path16) == -1) return -1;
-  if (flags & AT_REMOVEDIR) {
-    return sys_rmdir_nt(path16);
+  int n, rc;
+  char16_t path16[PATH_MAX];
+  if ((n = __mkntpathat(dirfd, path, 0, path16)) == -1) {
+    rc = -1;
+  } else if (flags & AT_REMOVEDIR) {
+    rc = sys_rmdir_nt(path16);
   } else {
-    return sys_unlink_nt(path16);
+    rc = sys_unlink_nt(path16);
+    if (rc != -1) {
+      // TODO(jart): prove that it helps first
+      // rc = SyncDirectory(dirfd, path16, n);
+    }
   }
+  return rc;
 }