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-rw-r--r--pkg/sentry/syscalls/linux/linux64.go2
-rw-r--r--pkg/sentry/syscalls/linux/sys_read.go33
-rw-r--r--test/syscalls/BUILD5
-rw-r--r--test/syscalls/linux/BUILD14
-rw-r--r--test/syscalls/linux/readahead.cc91
5 files changed, 144 insertions, 1 deletions
diff --git a/pkg/sentry/syscalls/linux/linux64.go b/pkg/sentry/syscalls/linux/linux64.go
index 18d24ab61..61acd0abd 100644
--- a/pkg/sentry/syscalls/linux/linux64.go
+++ b/pkg/sentry/syscalls/linux/linux64.go
@@ -232,7 +232,7 @@ var AMD64 = &kernel.SyscallTable{
184: syscalls.Error("tuxcall", syserror.ENOSYS, "Not implemented in Linux.", nil),
185: syscalls.Error("security", syserror.ENOSYS, "Not implemented in Linux.", nil),
186: syscalls.Supported("gettid", Gettid),
- 187: syscalls.ErrorWithEvent("readahead", syserror.ENOSYS, "", []string{"gvisor.dev/issue/261"}), // TODO(b/29351341)
+ 187: syscalls.Supported("readahead", Readahead),
188: syscalls.Error("setxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
189: syscalls.Error("lsetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
190: syscalls.Error("fsetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
diff --git a/pkg/sentry/syscalls/linux/sys_read.go b/pkg/sentry/syscalls/linux/sys_read.go
index 3ab54271c..cd31e0649 100644
--- a/pkg/sentry/syscalls/linux/sys_read.go
+++ b/pkg/sentry/syscalls/linux/sys_read.go
@@ -72,6 +72,39 @@ func Read(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC
return uintptr(n), nil, handleIOError(t, n != 0, err, kernel.ERESTARTSYS, "read", file)
}
+// Readahead implements readahead(2).
+func Readahead(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ fd := args[0].Int()
+ offset := args[1].Int64()
+ size := args[2].SizeT()
+
+ file := t.GetFile(fd)
+ if file == nil {
+ return 0, nil, syserror.EBADF
+ }
+ defer file.DecRef()
+
+ // Check that the file is readable.
+ if !file.Flags().Read {
+ return 0, nil, syserror.EBADF
+ }
+
+ // Check that the size is valid.
+ if int(size) < 0 {
+ return 0, nil, syserror.EINVAL
+ }
+
+ // Check that the offset is legitimate.
+ if offset < 0 {
+ return 0, nil, syserror.EINVAL
+ }
+
+ // Return EINVAL; if the underlying file type does not support readahead,
+ // then Linux will return EINVAL to indicate as much. In the future, we
+ // may extend this function to actually support readahead hints.
+ return 0, nil, syserror.EINVAL
+}
+
// Pread64 implements linux syscall pread64(2).
func Pread64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
fd := args[0].Int()
diff --git a/test/syscalls/BUILD b/test/syscalls/BUILD
index 63e4c63dd..341e6b252 100644
--- a/test/syscalls/BUILD
+++ b/test/syscalls/BUILD
@@ -346,6 +346,11 @@ syscall_test(
)
syscall_test(
+ add_overlay = True,
+ test = "//test/syscalls/linux:readahead_test",
+)
+
+syscall_test(
size = "medium",
shard_count = 5,
test = "//test/syscalls/linux:readv_socket_test",
diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD
index a4cebf46f..28b23ce58 100644
--- a/test/syscalls/linux/BUILD
+++ b/test/syscalls/linux/BUILD
@@ -1736,6 +1736,20 @@ cc_binary(
)
cc_binary(
+ name = "readahead_test",
+ testonly = 1,
+ srcs = ["readahead.cc"],
+ linkstatic = 1,
+ deps = [
+ "//test/util:file_descriptor",
+ "//test/util:temp_path",
+ "//test/util:test_main",
+ "//test/util:test_util",
+ "@com_google_googletest//:gtest",
+ ],
+)
+
+cc_binary(
name = "readv_test",
testonly = 1,
srcs = [
diff --git a/test/syscalls/linux/readahead.cc b/test/syscalls/linux/readahead.cc
new file mode 100644
index 000000000..09703b5c1
--- /dev/null
+++ b/test/syscalls/linux/readahead.cc
@@ -0,0 +1,91 @@
+// Copyright 2019 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 "gtest/gtest.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/temp_path.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+TEST(ReadaheadTest, InvalidFD) {
+ EXPECT_THAT(readahead(-1, 1, 1), SyscallFailsWithErrno(EBADF));
+}
+
+TEST(ReadaheadTest, InvalidOffset) {
+ const TempPath in_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
+ const FileDescriptor fd =
+ ASSERT_NO_ERRNO_AND_VALUE(Open(in_file.path(), O_RDWR));
+ EXPECT_THAT(readahead(fd.get(), -1, 1), SyscallFailsWithErrno(EINVAL));
+}
+
+TEST(ReadaheadTest, ValidOffset) {
+ constexpr char kData[] = "123";
+ const TempPath in_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+ GetAbsoluteTestTmpdir(), kData, TempPath::kDefaultFileMode));
+ const FileDescriptor fd =
+ ASSERT_NO_ERRNO_AND_VALUE(Open(in_file.path(), O_RDWR));
+
+ // N.B. The implementation of readahead is filesystem-specific, and a file
+ // backed by ram may return EINVAL because there is nothing to be read.
+ EXPECT_THAT(readahead(fd.get(), 1, 1), AnyOf(SyscallSucceedsWithValue(0),
+ SyscallFailsWithErrno(EINVAL)));
+}
+
+TEST(ReadaheadTest, PastEnd) {
+ constexpr char kData[] = "123";
+ const TempPath in_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+ GetAbsoluteTestTmpdir(), kData, TempPath::kDefaultFileMode));
+ const FileDescriptor fd =
+ ASSERT_NO_ERRNO_AND_VALUE(Open(in_file.path(), O_RDWR));
+ // See above.
+ EXPECT_THAT(readahead(fd.get(), 2, 2), AnyOf(SyscallSucceedsWithValue(0),
+ SyscallFailsWithErrno(EINVAL)));
+}
+
+TEST(ReadaheadTest, CrossesEnd) {
+ constexpr char kData[] = "123";
+ const TempPath in_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
+ GetAbsoluteTestTmpdir(), kData, TempPath::kDefaultFileMode));
+ const FileDescriptor fd =
+ ASSERT_NO_ERRNO_AND_VALUE(Open(in_file.path(), O_RDWR));
+ // See above.
+ EXPECT_THAT(readahead(fd.get(), 4, 2), AnyOf(SyscallSucceedsWithValue(0),
+ SyscallFailsWithErrno(EINVAL)));
+}
+
+TEST(ReadaheadTest, WriteOnly) {
+ const TempPath in_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
+ const FileDescriptor fd =
+ ASSERT_NO_ERRNO_AND_VALUE(Open(in_file.path(), O_WRONLY));
+ EXPECT_THAT(readahead(fd.get(), 0, 1), SyscallFailsWithErrno(EBADF));
+}
+
+TEST(ReadaheadTest, InvalidSize) {
+ const TempPath in_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
+ const FileDescriptor fd =
+ ASSERT_NO_ERRNO_AND_VALUE(Open(in_file.path(), O_RDWR));
+ EXPECT_THAT(readahead(fd.get(), 0, -1), SyscallFailsWithErrno(EINVAL));
+}
+
+} // namespace
+
+} // namespace testing
+} // namespace gvisor
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 11:30:52 +0000