3 files changed, 145 insertions, 0 deletions
diff --git a/test/util/BUILD b/test/util/BUILD
index 2a17c33ee..fc5fb3a8d 100644
--- a/test/util/BUILD
+++ b/test/util/BUILD
@@ -46,6 +46,13 @@ cc_library(
 )
 
 cc_library(
+    name = "fuse_util",
+    testonly = 1,
+    srcs = ["fuse_util.cc"],
+    hdrs = ["fuse_util.h"],
+)
+
+cc_library(
     name = "proc_util",
     testonly = 1,
     srcs = ["proc_util.cc"],
diff --git a/test/util/fuse_util.cc b/test/util/fuse_util.cc
new file mode 100644
index 000000000..027f8386c
--- /dev/null
+++ b/test/util/fuse_util.cc
@@ -0,0 +1,63 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "test/util/fuse_util.h"
+
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <string>
+
+namespace gvisor {
+namespace testing {
+
+// Create a default FuseAttr struct with specified mode, inode, and size.
+fuse_attr DefaultFuseAttr(mode_t mode, uint64_t inode, uint64_t size) {
+  const int time_sec = 1595436289;
+  const int time_nsec = 134150844;
+  return (struct fuse_attr){
+      .ino = inode,
+      .size = size,
+      .blocks = 4,
+      .atime = time_sec,
+      .mtime = time_sec,
+      .ctime = time_sec,
+      .atimensec = time_nsec,
+      .mtimensec = time_nsec,
+      .ctimensec = time_nsec,
+      .mode = mode,
+      .nlink = 2,
+      .uid = 1234,
+      .gid = 4321,
+      .rdev = 12,
+      .blksize = 4096,
+  };
+}
+
+// Create response body with specified mode, nodeID, and size.
+fuse_entry_out DefaultEntryOut(mode_t mode, uint64_t node_id, uint64_t size) {
+  struct fuse_entry_out default_entry_out = {
+      .nodeid = node_id,
+      .generation = 0,
+      .entry_valid = 0,
+      .attr_valid = 0,
+      .entry_valid_nsec = 0,
+      .attr_valid_nsec = 0,
+      .attr = DefaultFuseAttr(mode, node_id, size),
+  };
+  return default_entry_out;
+}
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/util/fuse_util.h b/test/util/fuse_util.h
new file mode 100644
index 000000000..544fe1b38
--- /dev/null
+++ b/test/util/fuse_util.h
@@ -0,0 +1,75 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef GVISOR_TEST_UTIL_FUSE_UTIL_H_
+#define GVISOR_TEST_UTIL_FUSE_UTIL_H_
+
+#include <linux/fuse.h>
+#include <sys/uio.h>
+
+#include <string>
+#include <vector>
+
+namespace gvisor {
+namespace testing {
+
+// The fundamental generation function with a single argument. If passed by
+// std::string or std::vector<char>, it will call specialized versions as
+// implemented below.
+template <typename T>
+std::vector<struct iovec> FuseGenerateIovecs(T &first) {
+  return {(struct iovec){.iov_base = &first, .iov_len = sizeof(first)}};
+}
+
+// If an argument is of type std::string, it must be used in read-only scenario.
+// Because we are setting up iovec, which contains the original address of a
+// data structure, we have to drop const qualification. Usually used with
+// variable-length payload data.
+template <typename T = std::string>
+std::vector<struct iovec> FuseGenerateIovecs(std::string &first) {
+  // Pad one byte for null-terminate c-string.
+  return {(struct iovec){.iov_base = const_cast<char *>(first.c_str()),
+                         .iov_len = first.size() + 1}};
+}
+
+// If an argument is of type std::vector<char>, it must be used in write-only
+// scenario and the size of the variable must be greater than or equal to the
+// size of the expected data. Usually used with variable-length payload data.
+template <typename T = std::vector<char>>
+std::vector<struct iovec> FuseGenerateIovecs(std::vector<char> &first) {
+  return {(struct iovec){.iov_base = first.data(), .iov_len = first.size()}};
+}
+
+// A helper function to set up an array of iovec struct for testing purpose.
+// Use variadic class template to generalize different numbers and different
+// types of FUSE structs.
+template <typename T, typename... Types>
+std::vector<struct iovec> FuseGenerateIovecs(T &first, Types &...args) {
+  auto first_iovec = FuseGenerateIovecs(first);
+  auto iovecs = FuseGenerateIovecs(args...);
+  first_iovec.insert(std::end(first_iovec), std::begin(iovecs),
+                     std::end(iovecs));
+  return first_iovec;
+}
+
+// Create a fuse_attr filled with the specified mode and inode.
+fuse_attr DefaultFuseAttr(mode_t mode, uint64_t inode, uint64_t size = 512);
+
+// Return a fuse_entry_out FUSE server response body.
+fuse_entry_out DefaultEntryOut(mode_t mode, uint64_t node_id,
+                               uint64_t size = 512);
+
+}  // namespace testing
+}  // namespace gvisor
+#endif  // GVISOR_TEST_UTIL_FUSE_UTIL_H_