Allow fuchsia to open non-regular files.

runtime/bin/file_fuchsia.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(HOST_OS_FUCHSIA)
 
 #include "bin/file.h"
 
 #include <errno.h>      // NOLINT
@@ skipping 175 matching lines @@
 }
 
 
 File* File::FileOpenW(const wchar_t* system_name, FileOpenMode mode) {
   UNREACHABLE();
   return NULL;
 }
 
 
 File* File::Open(const char* name, FileOpenMode mode) {
-  // Report errors for non-regular files.
-  struct stat st;
-  if (NO_RETRY_EXPECTED(stat(name, &st)) == 0) {

[zra, 2017/04/26 17:34:13]

Could you explain why this is needed?

This change removes the failure if the path is for a directory.

It looks like there was a change on the Linux side that wasn't ported here.
Maybe it would help. I.e.:

if (TEMP_FAILURE_RETRY(stat64(name, &st)) == 0) {
    // Only accept regular files, character devices, and pipes.
    if (!S_ISREG(st.st_mode) && !S_ISCHR(st.st_mode) && !S_ISFIFO(st.st_mode)) {
      errno = (S_ISDIR(st.st_mode)) ? EISDIR : ENOENT;
      return NULL;
    }
  }

-    if (!S_ISREG(st.st_mode)) {
-      errno = (S_ISDIR(st.st_mode)) ? EISDIR : ENOENT;
-      return NULL;
-    }
-  }
   int flags = O_RDONLY;
   if ((mode & kWrite) != 0) {
     ASSERT((mode & kWriteOnly) == 0);
     flags = (O_RDWR | O_CREAT);
   }
   if ((mode & kWriteOnly) != 0) {
     ASSERT((mode & kWrite) == 0);
     flags = (O_WRONLY | O_CREAT);
   }
   if ((mode & kTruncate) != 0) {
@@ skipping 355 matching lines @@
   return ((file_1_info.st_ino == file_2_info.st_ino) &&
           (file_1_info.st_dev == file_2_info.st_dev))
              ? File::kIdentical
              : File::kDifferent;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(HOST_OS_FUCHSIA)