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

If one tries to upload a file that one doesn't have read access to,
the browser livelocks. It tries to read from the file, gets nothing
but spins forever because it knows that it hasn't finished reading.

To address this, firstly we add a check at stat() time to make sure
that we can read the file. However, this doesn't take care of the case
where the access() call was incorrect, or the permissions have changed
under us. In this case, we replace the missing file with NULs.

(Land attempt three: first in r39446, reverted in r39448. Second in
r39899, reverted in r39901.)

http://codereview.chromium.org/541022
BUG=30850
TEST=Try to upload a file that isn't readable (i.e. /etc/shadow). The resulting upload should be a 0 byte file.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@40146 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 31 insertions, 10 deletions

diff --git a/net/base/file_stream_win.cc b/net/base/file_stream_win.cc
index cec6a9d..e1928a7 100644
--- a/net/base/file_stream_win.cc
+++ b/net/base/file_stream_win.cc
@@ -120,16 +120,10 @@ FileStream::FileStream()
       open_flags_(0) {
 }
 
-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(this));
-    MessageLoopForIO::current()->RegisterIOHandler(file_,
-                                                   async_context_.get());
-  }
+FileStream::FileStream(base::PlatformFile file, int open_flags)
+    : file_(INVALID_HANDLE_VALUE),
+      open_flags_(0) {
+  Open(file, open_flags);
 }
 
 FileStream::~FileStream() {
@@ -147,6 +141,13 @@ void FileStream::Close() {
   }
 }
 
+void FileStream::Release() {
+  if (file_ != INVALID_HANDLE_VALUE)
+    CancelIo(file_);
+  async_context_.reset();
+  file_ = INVALID_HANDLE_VALUE;
+}
+
 int FileStream::Open(const FilePath& path, int open_flags) {
   if (IsOpen()) {
     DLOG(FATAL) << "File is already open!";
@@ -170,6 +171,26 @@ int FileStream::Open(const FilePath& path, int open_flags) {
   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 the file handle is opened with base::PLATFORM_FILE_ASYNC, we need to
+  // make sure we will perform asynchronous File IO to it.
+  if (open_flags_ & base::PLATFORM_FILE_ASYNC) {
+    async_context_.reset(new AsyncContext(this));
+    MessageLoopForIO::current()->RegisterIOHandler(file_,
+                                                   async_context_.get());
+  }
+
+  return OK;
+}
+
 bool FileStream::IsOpen() const {
   return file_ != INVALID_HANDLE_VALUE;
 }