1 files changed, 121 insertions, 0 deletions
diff --git a/pkg/sentry/fs/flags.go b/pkg/sentry/fs/flags.go
new file mode 100644
index 000000000..5c8cb773f
--- /dev/null
+++ b/pkg/sentry/fs/flags.go
@@ -0,0 +1,121 @@
+// Copyright 2018 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.
+
+package fs
+
+import (
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+)
+
+// FileFlags encodes file flags.
+//
+// +stateify savable
+type FileFlags struct {
+	// Direct indicates that I/O should be done directly.
+	Direct bool
+
+	// NonBlocking indicates that I/O should not block.
+	NonBlocking bool
+
+	// Sync indicates that any writes should be synchronous.
+	Sync bool
+
+	// Append indicates this file is append only.
+	Append bool
+
+	// Read indicates this file is readable.
+	Read bool
+
+	// Write indicates this file is writeable.
+	Write bool
+
+	// Pread indicates this file is readable at an arbitrary offset.
+	Pread bool
+
+	// Pwrite indicates this file is writable at an arbitrary offset.
+	Pwrite bool
+
+	// Directory indicates that this file must be a directory.
+	Directory bool
+
+	// Async indicates that this file sends signals on IO events.
+	Async bool
+
+	// LargeFile indicates that this file should be opened even if it has
+	// size greater than linux's off_t. When running in 64-bit mode,
+	// Linux sets this flag for all files. Since gVisor is only compatible
+	// with 64-bit Linux, it also sets this flag for all files.
+	LargeFile bool
+}
+
+// SettableFileFlags is a subset of FileFlags above that can be changed
+// via fcntl(2) using the F_SETFL command.
+type SettableFileFlags struct {
+	// Direct indicates that I/O should be done directly.
+	Direct bool
+
+	// NonBlocking indicates that I/O should not block.
+	NonBlocking bool
+
+	// Append indicates this file is append only.
+	Append bool
+
+	// Async indicates that this file sends signals on IO events.
+	Async bool
+}
+
+// Settable returns the subset of f that are settable.
+func (f FileFlags) Settable() SettableFileFlags {
+	return SettableFileFlags{
+		Direct:      f.Direct,
+		NonBlocking: f.NonBlocking,
+		Append:      f.Append,
+		Async:       f.Async,
+	}
+}
+
+// ToLinux converts a FileFlags object to a Linux representation.
+func (f FileFlags) ToLinux() (mask uint) {
+	if f.Direct {
+		mask |= linux.O_DIRECT
+	}
+	if f.NonBlocking {
+		mask |= linux.O_NONBLOCK
+	}
+	if f.Sync {
+		mask |= linux.O_SYNC
+	}
+	if f.Append {
+		mask |= linux.O_APPEND
+	}
+	if f.Directory {
+		mask |= linux.O_DIRECTORY
+	}
+	if f.Async {
+		mask |= linux.O_ASYNC
+	}
+	if f.LargeFile {
+		mask |= linux.O_LARGEFILE
+	}
+
+	switch {
+	case f.Read && f.Write:
+		mask |= linux.O_RDWR
+	case f.Write:
+		mask |= linux.O_WRONLY
+	case f.Read:
+		mask |= linux.O_RDONLY
+	}
+	return
+}