Fix the case where the browser livelocks if we cannot open a file.

net/base/file_stream_posix.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // For 64-bit file access (off_t = off64_t, lseek64, etc).
 #define _FILE_OFFSET_BITS 64
 
 #include "net/base/file_stream.h"
 
 #include <sys/types.h>
@@ skipping 280 matching lines @@
 
 // FileStream ------------------------------------------------------------
 
 FileStream::FileStream()
     : file_(base::kInvalidPlatformFileValue),
       open_flags_(0) {
   DCHECK(!IsOpen());
 }
 
 FileStream::FileStream(base::PlatformFile file, int flags)
-    : file_(file),
-      open_flags_(flags) {
-  // If the file handle is opened with base::PLATFORM_FILE_ASYNC, we need to
-  // make sure we will perform asynchronous File IO to it.
-  if (flags & base::PLATFORM_FILE_ASYNC) {
-    async_context_.reset(new AsyncContext());
-  }
+    : file_(base::kInvalidPlatformFileValue) {
+  Open(file, flags);
 }
 
 FileStream::~FileStream() {
   Close();
 }
 
 void FileStream::Close() {
   // Abort any existing asynchronous operations.
   async_context_.reset();
 
   if (file_ != base::kInvalidPlatformFileValue) {
     if (close(file_) != 0) {
       NOTREACHED();
     }
     file_ = base::kInvalidPlatformFileValue;
   }
 }
 
+void FileStream::Release() {
+  // Abort any existing asynchronous operations.
+  async_context_.reset();
+  file_ = base::kInvalidPlatformFileValue;
+}
+
 int FileStream::Open(const FilePath& path, int open_flags) {
   if (IsOpen()) {
     DLOG(FATAL) << "File is already open!";
     return ERR_UNEXPECTED;
   }
 
   open_flags_ = open_flags;
   file_ = base::CreatePlatformFile(path, open_flags_, NULL);
   if (file_ == base::kInvalidPlatformFileValue) {
     LOG(WARNING) << "Failed to open file: " << errno
           << " (" << path.ToWStringHack() << ")";
     return MapErrorCode(errno);
   }
 
   if (open_flags_ & base::PLATFORM_FILE_ASYNC) {
     async_context_.reset(new AsyncContext());
   }
 
   return OK;
 }
 
+int FileStream::Open(base::PlatformFile file, int open_flags) {
+  if (IsOpen()) {
+    DLOG(FATAL) << "File is already open!";
+    return ERR_UNEXPECTED;
+  }
+
+  open_flags_ = open_flags;
+  file_ = file;
+
+  if (open_flags & base::PLATFORM_FILE_ASYNC)
+    async_context_.reset(new AsyncContext());
+
+  return OK;
+}
+
 bool FileStream::IsOpen() const {
   return file_ != base::kInvalidPlatformFileValue;
 }
 
 int64 FileStream::Seek(Whence whence, int64 offset) {
   if (!IsOpen())
     return ERR_UNEXPECTED;
 
   // If we're in async, make sure we don't have a request in flight.
   DCHECK(!async_context_.get() || !async_context_->callback());
@@ skipping 81 matching lines @@
     return ERR_IO_PENDING;
   } else {
     return WriteFile(file_, buf, buf_len);
   }
 }
 
 int64 FileStream::Truncate(int64 bytes) {
   if (!IsOpen())
     return ERR_UNEXPECTED;
 
-  // We better be open for reading.
+  // We better be open for writing.
   DCHECK(open_flags_ & base::PLATFORM_FILE_WRITE);
 
   // Seek to the position to truncate from.
   int64 seek_position = Seek(FROM_BEGIN, bytes);
   if (seek_position != bytes)
     return ERR_UNEXPECTED;
 
   // And truncate the file.
   int result = ftruncate(file_, bytes);
   return result == 0 ? seek_position : MapErrorCode(errno);
 }
 
 }  // namespace net