1 files changed, 135 insertions, 0 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_inotify.go b/pkg/sentry/syscalls/linux/sys_inotify.go
new file mode 100644
index 000000000..725204dff
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/sys_inotify.go
@@ -0,0 +1,135 @@
+// Copyright 2018 Google Inc.
+//
+// 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 linux
+
+import (
+	"syscall"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs/anon"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel/kdefs"
+)
+
+const allFlags = int(linux.IN_NONBLOCK | linux.IN_CLOEXEC)
+
+// InotifyInit1 implements the inotify_init1() syscalls.
+func InotifyInit1(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	flags := int(args[0].Int())
+
+	if flags&^allFlags != 0 {
+		return 0, nil, syscall.EINVAL
+	}
+
+	dirent := fs.NewDirent(anon.NewInode(t), "inotify")
+	fileFlags := fs.FileFlags{
+		Read:        true,
+		Write:       true,
+		NonBlocking: flags&linux.IN_NONBLOCK != 0,
+	}
+	n := fs.NewFile(t, dirent, fileFlags, fs.NewInotify(t))
+	defer n.DecRef()
+
+	fd, err := t.FDMap().NewFDFrom(0, n, kernel.FDFlags{
+		CloseOnExec: flags&linux.IN_CLOEXEC != 0,
+	}, t.ThreadGroup().Limits())
+
+	if err != nil {
+		return 0, nil, err
+	}
+
+	return uintptr(fd), nil, nil
+}
+
+// InotifyInit implements the inotify_init() syscalls.
+func InotifyInit(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	args[0].Value = 0
+	return InotifyInit1(t, args)
+}
+
+// fdToInotify resolves an fd to an inotify object. If successful, the file will
+// have an extra ref and the caller is responsible for releasing the ref.
+func fdToInotify(t *kernel.Task, fd kdefs.FD) (*fs.Inotify, *fs.File, error) {
+	file := t.FDMap().GetFile(fd)
+	if file == nil {
+		// Invalid fd.
+		return nil, nil, syscall.EBADF
+	}
+
+	ino, ok := file.FileOperations.(*fs.Inotify)
+	if !ok {
+		// Not an inotify fd.
+		file.DecRef()
+		return nil, nil, syscall.EINVAL
+	}
+
+	return ino, file, nil
+}
+
+// InotifyAddWatch implements the inotify_add_watch() syscall.
+func InotifyAddWatch(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	fd := kdefs.FD(args[0].Int())
+	addr := args[1].Pointer()
+	mask := args[2].Uint()
+
+	// "IN_DONT_FOLLOW: Don't dereference pathname if it is a symbolic link."
+	//  -- inotify(7)
+	resolve := mask&linux.IN_DONT_FOLLOW == 0
+
+	// "EINVAL: The given event mask contains no valid events."
+	// -- inotify_add_watch(2)
+	if validBits := mask & linux.ALL_INOTIFY_BITS; validBits == 0 {
+		return 0, nil, syscall.EINVAL
+	}
+
+	ino, file, err := fdToInotify(t, fd)
+	if err != nil {
+		return 0, nil, err
+	}
+	defer file.DecRef()
+
+	path, _, err := copyInPath(t, addr, false /* allowEmpty */)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	err = fileOpOn(t, linux.AT_FDCWD, path, resolve, func(root *fs.Dirent, dirent *fs.Dirent) error {
+		// "IN_ONLYDIR: Only watch pathname if it is a directory." -- inotify(7)
+		if onlyDir := mask&linux.IN_ONLYDIR != 0; onlyDir && !fs.IsDir(dirent.Inode.StableAttr) {
+			return syscall.ENOTDIR
+		}
+
+		// Copy out to the return frame.
+		fd = kdefs.FD(ino.AddWatch(dirent, mask))
+
+		return nil
+	})
+	return uintptr(fd), nil, err // Return from the existing value.
+}
+
+// InotifyRmWatch implements the inotify_rm_watch() syscall.
+func InotifyRmWatch(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	fd := kdefs.FD(args[0].Int())
+	wd := args[1].Int()
+
+	ino, file, err := fdToInotify(t, fd)
+	if err != nil {
+		return 0, nil, err
+	}
+	defer file.DecRef()
+	return 0, nil, ino.RmWatch(wd)
+}