134 lines
3.8 KiB
Go
134 lines
3.8 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package linux
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import (
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/sentry/arch"
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"gvisor.dev/gvisor/pkg/sentry/fs"
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"gvisor.dev/gvisor/pkg/sentry/fs/anon"
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"gvisor.dev/gvisor/pkg/sentry/kernel"
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"gvisor.dev/gvisor/pkg/syserror"
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)
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const allFlags = int(linux.IN_NONBLOCK | linux.IN_CLOEXEC)
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// InotifyInit1 implements the inotify_init1() syscalls.
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func InotifyInit1(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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flags := int(args[0].Int())
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if flags&^allFlags != 0 {
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return 0, nil, syserror.EINVAL
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}
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dirent := fs.NewDirent(t, anon.NewInode(t), "inotify")
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fileFlags := fs.FileFlags{
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Read: true,
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Write: true,
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NonBlocking: flags&linux.IN_NONBLOCK != 0,
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}
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n := fs.NewFile(t, dirent, fileFlags, fs.NewInotify(t))
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defer n.DecRef()
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fd, err := t.NewFDFrom(0, n, kernel.FDFlags{
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CloseOnExec: flags&linux.IN_CLOEXEC != 0,
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})
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if err != nil {
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return 0, nil, err
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}
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return uintptr(fd), nil, nil
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}
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// InotifyInit implements the inotify_init() syscalls.
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func InotifyInit(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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args[0].Value = 0
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return InotifyInit1(t, args)
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}
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// fdToInotify resolves an fd to an inotify object. If successful, the file will
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// have an extra ref and the caller is responsible for releasing the ref.
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func fdToInotify(t *kernel.Task, fd int32) (*fs.Inotify, *fs.File, error) {
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file := t.GetFile(fd)
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if file == nil {
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// Invalid fd.
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return nil, nil, syserror.EBADF
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}
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ino, ok := file.FileOperations.(*fs.Inotify)
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if !ok {
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// Not an inotify fd.
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file.DecRef()
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return nil, nil, syserror.EINVAL
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}
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return ino, file, nil
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}
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// InotifyAddWatch implements the inotify_add_watch() syscall.
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func InotifyAddWatch(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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fd := args[0].Int()
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addr := args[1].Pointer()
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mask := args[2].Uint()
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// "IN_DONT_FOLLOW: Don't dereference pathname if it is a symbolic link."
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// -- inotify(7)
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resolve := mask&linux.IN_DONT_FOLLOW == 0
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// "EINVAL: The given event mask contains no valid events."
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// -- inotify_add_watch(2)
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if validBits := mask & linux.ALL_INOTIFY_BITS; validBits == 0 {
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return 0, nil, syserror.EINVAL
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}
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ino, file, err := fdToInotify(t, fd)
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if err != nil {
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return 0, nil, err
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}
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defer file.DecRef()
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path, _, err := copyInPath(t, addr, false /* allowEmpty */)
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if err != nil {
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return 0, nil, err
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}
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err = fileOpOn(t, linux.AT_FDCWD, path, resolve, func(root *fs.Dirent, dirent *fs.Dirent, _ uint) error {
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// "IN_ONLYDIR: Only watch pathname if it is a directory." -- inotify(7)
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if onlyDir := mask&linux.IN_ONLYDIR != 0; onlyDir && !fs.IsDir(dirent.Inode.StableAttr) {
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return syserror.ENOTDIR
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}
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// Copy out to the return frame.
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fd = ino.AddWatch(dirent, mask)
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return nil
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})
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return uintptr(fd), nil, err // Return from the existing value.
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}
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// InotifyRmWatch implements the inotify_rm_watch() syscall.
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func InotifyRmWatch(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
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fd := args[0].Int()
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wd := args[1].Int()
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ino, file, err := fdToInotify(t, fd)
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if err != nil {
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return 0, nil, err
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}
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defer file.DecRef()
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return 0, nil, ino.RmWatch(wd)
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}
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