Implement FUSE_WRITE

This commit adds basic write(2) support for FUSE.

5 files changed, 332 insertions, 9 deletions

diff --git a/test/fuse/BUILD b/test/fuse/BUILD
index 1a6b5b516..55ad98748 100644
--- a/test/fuse/BUILD
+++ b/test/fuse/BUILD
@@ -44,6 +44,11 @@ syscall_test(
 
 syscall_test(
     fuse = "True",
+    test = "//test/fuse/linux:write_test",
+)
+
+syscall_test(
+    fuse = "True",
     test = "//test/fuse/linux:rmdir_test",
 )
 
diff --git a/test/fuse/linux/BUILD b/test/fuse/linux/BUILD
index 2bb956af9..cc5bd560e 100644
--- a/test/fuse/linux/BUILD
+++ b/test/fuse/linux/BUILD
@@ -155,6 +155,19 @@ cc_binary(
 )
 
 cc_binary(
+    name = "write_test",
+    testonly = 1,
+    srcs = ["write_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fuse_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
     name = "create_test",
     testonly = 1,
     srcs = ["create_test.cc"],
diff --git a/test/fuse/linux/fuse_base.cc b/test/fuse/linux/fuse_base.cc
index e3c6b585c..a033db117 100644
--- a/test/fuse/linux/fuse_base.cc
+++ b/test/fuse/linux/fuse_base.cc
@@ -164,7 +164,8 @@ void FuseTest::UnmountFuse() {
 }
 
 // Consumes the first FUSE request and returns the corresponding PosixError.
-PosixError FuseTest::ServerConsumeFuseInit() {
+PosixError FuseTest::ServerConsumeFuseInit(
+    const struct fuse_init_out* out_payload) {
   std::vector<char> buf(FUSE_MIN_READ_BUFFER);
   RETURN_ERROR_IF_SYSCALL_FAIL(
       RetryEINTR(read)(dev_fd_, buf.data(), buf.size()));
@@ -176,10 +177,8 @@ PosixError FuseTest::ServerConsumeFuseInit() {
   };
   // Returns a fake fuse_init_out with 7.0 version to avoid ECONNREFUSED
   // error in the initialization of FUSE connection.
-  struct fuse_init_out out_payload = {
-      .major = 7,
-  };
-  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  auto iov_out = FuseGenerateIovecs(
+      out_header, *const_cast<struct fuse_init_out*>(out_payload));
 
   RETURN_ERROR_IF_SYSCALL_FAIL(
       RetryEINTR(writev)(dev_fd_, iov_out.data(), iov_out.size()));
@@ -244,7 +243,7 @@ void FuseTest::ServerFuseLoop() {
 // becomes testing thread and the child thread becomes the FUSE server running
 // in background. These 2 threads are connected via socketpair. sock_[0] is
 // opened in testing thread and sock_[1] is opened in the FUSE server.
-void FuseTest::SetUpFuseServer() {
+void FuseTest::SetUpFuseServer(const struct fuse_init_out* payload) {
   ASSERT_THAT(socketpair(AF_UNIX, SOCK_STREAM, 0, sock_), SyscallSucceeds());
 
   switch (fork()) {
@@ -261,7 +260,7 @@ void FuseTest::SetUpFuseServer() {
 
   // Begin child thread, i.e. the FUSE server.
   ASSERT_THAT(close(sock_[0]), SyscallSucceeds());
-  ServerCompleteWith(ServerConsumeFuseInit().ok());
+  ServerCompleteWith(ServerConsumeFuseInit(payload).ok());
   ServerFuseLoop();
   _exit(0);
 }
diff --git a/test/fuse/linux/fuse_base.h b/test/fuse/linux/fuse_base.h
index 452748d6d..6ad296ca2 100644
--- a/test/fuse/linux/fuse_base.h
+++ b/test/fuse/linux/fuse_base.h
@@ -33,6 +33,8 @@ namespace testing {
 
 constexpr char kMountOpts[] = "rootmode=755,user_id=0,group_id=0";
 
+constexpr struct fuse_init_out kDefaultFUSEInitOutPayload = {.major = 7};
+
 // Internal commands used to communicate between testing thread and the FUSE
 // server. See test/fuse/README.md for further detail.
 enum class FuseTestCmd {
@@ -171,7 +173,8 @@ class FuseTest : public ::testing::Test {
   void MountFuse(const char* mountOpts = kMountOpts);
 
   // Creates a socketpair for communication and forks FUSE server.
-  void SetUpFuseServer();
+  void SetUpFuseServer(
+      const struct fuse_init_out* payload = &kDefaultFUSEInitOutPayload);
 
   // Unmounts the mountpoint of the FUSE server.
   void UnmountFuse();
@@ -194,7 +197,7 @@ class FuseTest : public ::testing::Test {
 
   // Consumes the first FUSE request when mounting FUSE. Replies with a
   // response with empty payload.
-  PosixError ServerConsumeFuseInit();
+  PosixError ServerConsumeFuseInit(const struct fuse_init_out* payload);
 
   // A command switch that dispatch different FuseTestCmd to its handler.
   void ServerHandleCommand();
diff --git a/test/fuse/linux/write_test.cc b/test/fuse/linux/write_test.cc
new file mode 100644
index 000000000..e7a1aff13
--- /dev/null
+++ b/test/fuse/linux/write_test.cc
@@ -0,0 +1,303 @@
+// 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 <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class WriteTest : public FuseTest {
+  void SetUp() override {
+    FuseTest::SetUp();
+    test_file_path_ = JoinPath(mount_point_.path().c_str(), test_file_);
+  }
+
+  // TearDown overrides the parent's function
+  // to skip checking the unconsumed release request at the end.
+  void TearDown() override { UnmountFuse(); }
+
+ protected:
+  const std::string test_file_ = "test_file";
+  const mode_t test_file_mode_ = S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO;
+  const uint64_t test_fh_ = 1;
+  const uint32_t open_flag_ = O_RDWR;
+
+  std::string test_file_path_;
+
+  PosixErrorOr<FileDescriptor> OpenTestFile(const std::string &path,
+                                            uint64_t size = 512) {
+    SetServerInodeLookup(test_file_, test_file_mode_, size);
+
+    struct fuse_out_header out_header_open = {
+        .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_open_out),
+    };
+    struct fuse_open_out out_payload_open = {
+        .fh = test_fh_,
+        .open_flags = open_flag_,
+    };
+    auto iov_out_open = FuseGenerateIovecs(out_header_open, out_payload_open);
+    SetServerResponse(FUSE_OPEN, iov_out_open);
+
+    auto res = Open(path.c_str(), open_flag_);
+    if (res.ok()) {
+      SkipServerActualRequest();
+    }
+    return res;
+  }
+};
+
+class WriteTestSmallMaxWrite : public WriteTest {
+  void SetUp() override {
+    MountFuse();
+    SetUpFuseServer(&fuse_init_payload);
+    test_file_path_ = JoinPath(mount_point_.path().c_str(), test_file_);
+  }
+
+ protected:
+  const static uint32_t max_write_ = 4096;
+  constexpr static struct fuse_init_out fuse_init_payload = {
+      .major = 7,
+      .max_write = max_write_,
+  };
+
+  const uint32_t size_fragment = max_write_;
+};
+
+TEST_F(WriteTest, WriteNormal) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Prepare for the write.
+  const int n_write = 10;
+  struct fuse_out_header out_header_write = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_write_out),
+  };
+  struct fuse_write_out out_payload_write = {
+      .size = n_write,
+  };
+  auto iov_out_write = FuseGenerateIovecs(out_header_write, out_payload_write);
+  SetServerResponse(FUSE_WRITE, iov_out_write);
+
+  // Issue the write.
+  std::vector<char> buf(n_write);
+  RandomizeBuffer(buf.data(), buf.size());
+  EXPECT_THAT(write(fd.get(), buf.data(), n_write),
+              SyscallSucceedsWithValue(n_write));
+
+  // Check the write request.
+  struct fuse_in_header in_header_write;
+  struct fuse_write_in in_payload_write;
+  std::vector<char> payload_buf(n_write);
+  auto iov_in_write =
+      FuseGenerateIovecs(in_header_write, in_payload_write, payload_buf);
+  GetServerActualRequest(iov_in_write);
+
+  EXPECT_EQ(in_payload_write.fh, test_fh_);
+  EXPECT_EQ(in_header_write.len,
+            sizeof(in_header_write) + sizeof(in_payload_write));
+  EXPECT_EQ(in_header_write.opcode, FUSE_WRITE);
+  EXPECT_EQ(in_payload_write.offset, 0);
+  EXPECT_EQ(in_payload_write.size, n_write);
+  EXPECT_EQ(buf, payload_buf);
+}
+
+TEST_F(WriteTest, WriteShort) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Prepare for the write.
+  const int n_write = 10, n_written = 5;
+  struct fuse_out_header out_header_write = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_write_out),
+  };
+  struct fuse_write_out out_payload_write = {
+      .size = n_written,
+  };
+  auto iov_out_write = FuseGenerateIovecs(out_header_write, out_payload_write);
+  SetServerResponse(FUSE_WRITE, iov_out_write);
+
+  // Issue the write.
+  std::vector<char> buf(n_write);
+  RandomizeBuffer(buf.data(), buf.size());
+  EXPECT_THAT(write(fd.get(), buf.data(), n_write),
+              SyscallSucceedsWithValue(n_written));
+
+  // Check the write request.
+  struct fuse_in_header in_header_write;
+  struct fuse_write_in in_payload_write;
+  std::vector<char> payload_buf(n_write);
+  auto iov_in_write =
+      FuseGenerateIovecs(in_header_write, in_payload_write, payload_buf);
+  GetServerActualRequest(iov_in_write);
+
+  EXPECT_EQ(in_payload_write.fh, test_fh_);
+  EXPECT_EQ(in_header_write.len,
+            sizeof(in_header_write) + sizeof(in_payload_write));
+  EXPECT_EQ(in_header_write.opcode, FUSE_WRITE);
+  EXPECT_EQ(in_payload_write.offset, 0);
+  EXPECT_EQ(in_payload_write.size, n_write);
+  EXPECT_EQ(buf, payload_buf);
+}
+
+TEST_F(WriteTest, WriteShortZero) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Prepare for the write.
+  const int n_write = 10;
+  struct fuse_out_header out_header_write = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_write_out),
+  };
+  struct fuse_write_out out_payload_write = {
+      .size = 0,
+  };
+  auto iov_out_write = FuseGenerateIovecs(out_header_write, out_payload_write);
+  SetServerResponse(FUSE_WRITE, iov_out_write);
+
+  // Issue the write.
+  std::vector<char> buf(n_write);
+  RandomizeBuffer(buf.data(), buf.size());
+  EXPECT_THAT(write(fd.get(), buf.data(), n_write), SyscallFailsWithErrno(EIO));
+
+  // Check the write request.
+  struct fuse_in_header in_header_write;
+  struct fuse_write_in in_payload_write;
+  std::vector<char> payload_buf(n_write);
+  auto iov_in_write =
+      FuseGenerateIovecs(in_header_write, in_payload_write, payload_buf);
+  GetServerActualRequest(iov_in_write);
+
+  EXPECT_EQ(in_payload_write.fh, test_fh_);
+  EXPECT_EQ(in_header_write.len,
+            sizeof(in_header_write) + sizeof(in_payload_write));
+  EXPECT_EQ(in_header_write.opcode, FUSE_WRITE);
+  EXPECT_EQ(in_payload_write.offset, 0);
+  EXPECT_EQ(in_payload_write.size, n_write);
+  EXPECT_EQ(buf, payload_buf);
+}
+
+TEST_F(WriteTest, WriteZero) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Issue the write.
+  std::vector<char> buf(0);
+  EXPECT_THAT(write(fd.get(), buf.data(), 0), SyscallSucceedsWithValue(0));
+}
+
+TEST_F(WriteTest, PWrite) {
+  const int file_size = 512;
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_, file_size));
+
+  // Prepare for the write.
+  const int n_write = 10;
+  struct fuse_out_header out_header_write = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_write_out),
+  };
+  struct fuse_write_out out_payload_write = {
+      .size = n_write,
+  };
+  auto iov_out_write = FuseGenerateIovecs(out_header_write, out_payload_write);
+  SetServerResponse(FUSE_WRITE, iov_out_write);
+
+  // Issue the write.
+  std::vector<char> buf(n_write);
+  RandomizeBuffer(buf.data(), buf.size());
+  const int offset_write = file_size >> 1;
+  EXPECT_THAT(pwrite(fd.get(), buf.data(), n_write, offset_write),
+              SyscallSucceedsWithValue(n_write));
+
+  // Check the write request.
+  struct fuse_in_header in_header_write;
+  struct fuse_write_in in_payload_write;
+  std::vector<char> payload_buf(n_write);
+  auto iov_in_write =
+      FuseGenerateIovecs(in_header_write, in_payload_write, payload_buf);
+  GetServerActualRequest(iov_in_write);
+
+  EXPECT_EQ(in_payload_write.fh, test_fh_);
+  EXPECT_EQ(in_header_write.len,
+            sizeof(in_header_write) + sizeof(in_payload_write));
+  EXPECT_EQ(in_header_write.opcode, FUSE_WRITE);
+  EXPECT_EQ(in_payload_write.offset, offset_write);
+  EXPECT_EQ(in_payload_write.size, n_write);
+  EXPECT_EQ(buf, payload_buf);
+}
+
+TEST_F(WriteTestSmallMaxWrite, WriteSmallMaxWrie) {
+  const int n_fragment = 10;
+  const int n_write = size_fragment * n_fragment;
+
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_, n_write));
+
+  // Prepare for the write.
+  struct fuse_out_header out_header_write = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_write_out),
+  };
+  struct fuse_write_out out_payload_write = {
+      .size = size_fragment,
+  };
+  auto iov_out_write = FuseGenerateIovecs(out_header_write, out_payload_write);
+
+  for (int i = 0; i < n_fragment; ++i) {
+    SetServerResponse(FUSE_WRITE, iov_out_write);
+  }
+
+  // Issue the write.
+  std::vector<char> buf(n_write);
+  RandomizeBuffer(buf.data(), buf.size());
+  EXPECT_THAT(write(fd.get(), buf.data(), n_write),
+              SyscallSucceedsWithValue(n_write));
+
+  ASSERT_EQ(GetServerNumUnsentResponses(), 0);
+  ASSERT_EQ(GetServerNumUnconsumedRequests(), n_fragment);
+
+  // Check the write request.
+  struct fuse_in_header in_header_write;
+  struct fuse_write_in in_payload_write;
+  std::vector<char> payload_buf(size_fragment);
+  auto iov_in_write =
+      FuseGenerateIovecs(in_header_write, in_payload_write, payload_buf);
+
+  for (int i = 0; i < n_fragment; ++i) {
+    GetServerActualRequest(iov_in_write);
+
+    EXPECT_EQ(in_payload_write.fh, test_fh_);
+    EXPECT_EQ(in_header_write.len,
+              sizeof(in_header_write) + sizeof(in_payload_write));
+    EXPECT_EQ(in_header_write.opcode, FUSE_WRITE);
+    EXPECT_EQ(in_payload_write.offset, i * size_fragment);
+    EXPECT_EQ(in_payload_write.size, size_fragment);
+
+    auto it = buf.begin() + i * size_fragment;
+    EXPECT_EQ(std::vector<char>(it, it + size_fragment), payload_buf);
+  }
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
\ No newline at end of file