[NaCl SDK] nacl_io: Fix FuseFs.{read,write}

native_client_sdk/src/libraries/nacl_io/fusefs/fuse_fs.cc

 // Copyright 2013 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.
 
 #include "nacl_io/fusefs/fuse_fs.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <string.h>
 
@@ skipping 323 matching lines @@
     LOG_ERROR("fuse_ops_->read is NULL.");
     return ENOSYS;
   }
 
   char* cbuf = static_cast<char*>(buf);
 
   int result = fuse_ops_->read(path_.c_str(), cbuf, count, attr.offs, &info_);
   if (result < 0)
     return -result;
 
-  // Fuse docs say that a read() call will always completely fill the buffer
-  // (padding with zeroes) unless the direct_io filesystem flag is set.
   // TODO(binji): support the direct_io flag
   if (static_cast<size_t>(result) < count)
     memset(&cbuf[result], 0, count - result);
 
-  *out_bytes = count;
+  *out_bytes = result;
   return 0;
 }
 
 Error FileFuseFsNode::Write(const HandleAttr& attr,
                             const void* buf,
                             size_t count,
                             int* out_bytes) {
   if (!fuse_ops_->write) {
     LOG_ERROR("fuse_ops_->write is NULL.");
     return ENOSYS;
   }
 
   int result = fuse_ops_->write(
       path_.c_str(), static_cast<const char*>(buf), count, attr.offs, &info_);
   if (result < 0)
     return -result;
 
-  // Fuse docs say that a write() call will always write the entire buffer
-  // unless the direct_io filesystem flag is set.
-  // TODO(binji): What should we do if the user breaks this contract? Warn?
   // TODO(binji): support the direct_io flag
   *out_bytes = result;
   return 0;
 }
 
 DirFuseFsNode::DirFuseFsNode(Filesystem* filesystem,
                              struct fuse_operations* fuse_ops,
                              struct fuse_file_info& info,
                              const std::string& path)
     : FuseFsNode(filesystem, fuse_ops, info, path) {
@@ skipping 96 matching lines @@
   } else {
     fill_info->getdents->AddDirent(ino, name, strlen(name));
     fill_info->num_bytes -= sizeof(dirent);
     // According to the docs, we can never return 1 (buffer full) when the
     // offset is zero (the user is probably ignoring the result anyway).
     return 0;
   }
 }
 
 }  // namespace nacl_io