diff options
| -rw-r--r-- | pkg/sentry/fsimpl/memfs/BUILD | 20 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/memfs/filesystem.go | 55 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/memfs/memfs.go | 2 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/memfs/named_pipe.go | 59 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/memfs/pipe_test.go | 233 | ||||
| -rw-r--r-- | pkg/sentry/kernel/pipe/vfs.go | 2 | ||||
| -rw-r--r-- | pkg/sentry/vfs/syscalls.go | 22 |
7 files changed, 380 insertions, 13 deletions
diff --git a/pkg/sentry/fsimpl/memfs/BUILD b/pkg/sentry/fsimpl/memfs/BUILD index 7e364c5fd..04d667273 100644 --- a/pkg/sentry/fsimpl/memfs/BUILD +++ b/pkg/sentry/fsimpl/memfs/BUILD @@ -24,14 +24,18 @@ go_library( "directory.go", "filesystem.go", "memfs.go", + "named_pipe.go", "regular_file.go", "symlink.go", ], importpath = "gvisor.dev/gvisor/pkg/sentry/fsimpl/memfs", deps = [ "//pkg/abi/linux", + "//pkg/amutex", + "//pkg/sentry/arch", "//pkg/sentry/context", "//pkg/sentry/kernel/auth", + "//pkg/sentry/kernel/pipe", "//pkg/sentry/usermem", "//pkg/sentry/vfs", "//pkg/syserror", @@ -54,3 +58,19 @@ go_test( "//pkg/syserror", ], ) + +go_test( + name = "memfs_test", + size = "small", + srcs = ["pipe_test.go"], + embed = [":memfs"], + deps = [ + "//pkg/abi/linux", + "//pkg/sentry/context", + "//pkg/sentry/context/contexttest", + "//pkg/sentry/kernel/auth", + "//pkg/sentry/usermem", + "//pkg/sentry/vfs", + "//pkg/syserror", + ], +) diff --git a/pkg/sentry/fsimpl/memfs/filesystem.go b/pkg/sentry/fsimpl/memfs/filesystem.go index f79e2d9c8..f006c40cd 100644 --- a/pkg/sentry/fsimpl/memfs/filesystem.go +++ b/pkg/sentry/fsimpl/memfs/filesystem.go @@ -233,7 +233,7 @@ func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts v if err != nil { return err } - _, err = checkCreateLocked(rp, parentVFSD, parentInode) + pc, err := checkCreateLocked(rp, parentVFSD, parentInode) if err != nil { return err } @@ -241,8 +241,40 @@ func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts v return err } defer rp.Mount().EndWrite() - // TODO: actually implement mknod - return syserror.EPERM + + switch opts.Mode.FileType() { + case 0: + // "Zero file type is equivalent to type S_IFREG." - mknod(2) + fallthrough + case linux.ModeRegular: + // TODO(b/138862511): Implement. + return syserror.EINVAL + + case linux.ModeNamedPipe: + child := fs.newDentry(fs.newNamedPipe(rp.Credentials(), opts.Mode)) + parentVFSD.InsertChild(&child.vfsd, pc) + parentInode.impl.(*directory).childList.PushBack(child) + return nil + + case linux.ModeSocket: + // TODO(b/138862511): Implement. + return syserror.EINVAL + + case linux.ModeCharacterDevice: + fallthrough + case linux.ModeBlockDevice: + // TODO(b/72101894): We don't support creating block or character + // devices at the moment. + // + // When we start supporting block and character devices, we'll + // need to check for CAP_MKNOD here. + return syserror.EPERM + + default: + // "EINVAL - mode requested creation of something other than a + // regular file, device special file, FIFO or socket." - mknod(2) + return syserror.EINVAL + } } // OpenAt implements vfs.FilesystemImpl.OpenAt. @@ -250,8 +282,9 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf // Filter out flags that are not supported by memfs. O_DIRECTORY and // O_NOFOLLOW have no effect here (they're handled by VFS by setting // appropriate bits in rp), but are returned by - // FileDescriptionImpl.StatusFlags(). - opts.Flags &= linux.O_ACCMODE | linux.O_CREAT | linux.O_EXCL | linux.O_TRUNC | linux.O_DIRECTORY | linux.O_NOFOLLOW + // FileDescriptionImpl.StatusFlags(). O_NONBLOCK is supported only by + // pipes. + opts.Flags &= linux.O_ACCMODE | linux.O_CREAT | linux.O_EXCL | linux.O_TRUNC | linux.O_DIRECTORY | linux.O_NOFOLLOW | linux.O_NONBLOCK if opts.Flags&linux.O_CREAT == 0 { fs.mu.RLock() @@ -260,7 +293,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf if err != nil { return nil, err } - return inode.open(rp, vfsd, opts.Flags, false) + return inode.open(ctx, rp, vfsd, opts.Flags, false) } mustCreate := opts.Flags&linux.O_EXCL != 0 @@ -275,7 +308,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf if mustCreate { return nil, syserror.EEXIST } - return inode.open(rp, vfsd, opts.Flags, false) + return inode.open(ctx, rp, vfsd, opts.Flags, false) } afterTrailingSymlink: // Walk to the parent directory of the last path component. @@ -320,7 +353,7 @@ afterTrailingSymlink: child := fs.newDentry(childInode) vfsd.InsertChild(&child.vfsd, pc) inode.impl.(*directory).childList.PushBack(child) - return childInode.open(rp, &child.vfsd, opts.Flags, true) + return childInode.open(ctx, rp, &child.vfsd, opts.Flags, true) } // Open existing file or follow symlink. if mustCreate { @@ -336,10 +369,10 @@ afterTrailingSymlink: // symlink target. goto afterTrailingSymlink } - return childInode.open(rp, childVFSD, opts.Flags, false) + return childInode.open(ctx, rp, childVFSD, opts.Flags, false) } -func (i *inode) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, flags uint32, afterCreate bool) (*vfs.FileDescription, error) { +func (i *inode) open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, flags uint32, afterCreate bool) (*vfs.FileDescription, error) { ats := vfs.AccessTypesForOpenFlags(flags) if !afterCreate { if err := i.checkPermissions(rp.Credentials(), ats, i.isDir()); err != nil { @@ -378,6 +411,8 @@ func (i *inode) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, flags uint32, afte case *symlink: // Can't open symlinks without O_PATH (which is unimplemented). return nil, syserror.ELOOP + case *namedPipe: + return newNamedPipeFD(ctx, impl, rp, vfsd, flags) default: panic(fmt.Sprintf("unknown inode type: %T", i.impl)) } diff --git a/pkg/sentry/fsimpl/memfs/memfs.go b/pkg/sentry/fsimpl/memfs/memfs.go index b78471c0f..64c851c1a 100644 --- a/pkg/sentry/fsimpl/memfs/memfs.go +++ b/pkg/sentry/fsimpl/memfs/memfs.go @@ -227,6 +227,8 @@ func (i *inode) statTo(stat *linux.Statx) { stat.Mask |= linux.STATX_SIZE | linux.STATX_BLOCKS stat.Size = uint64(len(impl.target)) stat.Blocks = allocatedBlocksForSize(stat.Size) + case *namedPipe: + stat.Mode |= linux.S_IFIFO default: panic(fmt.Sprintf("unknown inode type: %T", i.impl)) } diff --git a/pkg/sentry/fsimpl/memfs/named_pipe.go b/pkg/sentry/fsimpl/memfs/named_pipe.go new file mode 100644 index 000000000..732ed7c58 --- /dev/null +++ b/pkg/sentry/fsimpl/memfs/named_pipe.go @@ -0,0 +1,59 @@ +// 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. + +package memfs + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/context" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/kernel/pipe" + "gvisor.dev/gvisor/pkg/sentry/usermem" + "gvisor.dev/gvisor/pkg/sentry/vfs" +) + +type namedPipe struct { + inode inode + + pipe *pipe.VFSPipe +} + +// Preconditions: +// * fs.mu must be locked. +// * rp.Mount().CheckBeginWrite() has been called successfully. +func (fs *filesystem) newNamedPipe(creds *auth.Credentials, mode linux.FileMode) *inode { + file := &namedPipe{pipe: pipe.NewVFSPipe(pipe.DefaultPipeSize, usermem.PageSize)} + file.inode.init(file, fs, creds, mode) + file.inode.nlink = 1 // Only the parent has a link. + return &file.inode +} + +// namedPipeFD implements vfs.FileDescriptionImpl. Methods are implemented +// entirely via struct embedding. +type namedPipeFD struct { + fileDescription + + *pipe.VFSPipeFD +} + +func newNamedPipeFD(ctx context.Context, np *namedPipe, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, flags uint32) (*vfs.FileDescription, error) { + var err error + var fd namedPipeFD + fd.VFSPipeFD, err = np.pipe.NewVFSPipeFD(ctx, rp, vfsd, &fd.vfsfd, flags) + if err != nil { + return nil, err + } + fd.vfsfd.Init(&fd, rp.Mount(), vfsd) + return &fd.vfsfd, nil +} diff --git a/pkg/sentry/fsimpl/memfs/pipe_test.go b/pkg/sentry/fsimpl/memfs/pipe_test.go new file mode 100644 index 000000000..0674b81a3 --- /dev/null +++ b/pkg/sentry/fsimpl/memfs/pipe_test.go @@ -0,0 +1,233 @@ +// 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. + +package memfs + +import ( + "bytes" + "testing" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/context" + "gvisor.dev/gvisor/pkg/sentry/context/contexttest" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/usermem" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" +) + +const fileName = "mypipe" + +func TestSeparateFDs(t *testing.T) { + ctx, creds, vfsObj, root := setup(t) + defer root.DecRef() + + // Open the read side. This is done in a concurrently because opening + // One end the pipe blocks until the other end is opened. + pop := vfs.PathOperation{ + Root: root, + Start: root, + Pathname: fileName, + FollowFinalSymlink: true, + } + rfdchan := make(chan *vfs.FileDescription) + go func() { + openOpts := vfs.OpenOptions{Flags: linux.O_RDONLY} + rfd, _ := vfsObj.OpenAt(ctx, creds, &pop, &openOpts) + rfdchan <- rfd + }() + + // Open the write side. + openOpts := vfs.OpenOptions{Flags: linux.O_WRONLY} + wfd, err := vfsObj.OpenAt(ctx, creds, &pop, &openOpts) + if err != nil { + t.Fatalf("failed to open pipe for writing %q: %v", fileName, err) + } + defer wfd.DecRef() + + rfd, ok := <-rfdchan + if !ok { + t.Fatalf("failed to open pipe for reading %q", fileName) + } + defer rfd.DecRef() + + const msg = "vamos azul" + checkEmpty(ctx, t, rfd) + checkWrite(ctx, t, wfd, msg) + checkRead(ctx, t, rfd, msg) +} + +func TestNonblockingRead(t *testing.T) { + ctx, creds, vfsObj, root := setup(t) + defer root.DecRef() + + // Open the read side as nonblocking. + pop := vfs.PathOperation{ + Root: root, + Start: root, + Pathname: fileName, + FollowFinalSymlink: true, + } + openOpts := vfs.OpenOptions{Flags: linux.O_RDONLY | linux.O_NONBLOCK} + rfd, err := vfsObj.OpenAt(ctx, creds, &pop, &openOpts) + if err != nil { + t.Fatalf("failed to open pipe for reading %q: %v", fileName, err) + } + defer rfd.DecRef() + + // Open the write side. + openOpts = vfs.OpenOptions{Flags: linux.O_WRONLY} + wfd, err := vfsObj.OpenAt(ctx, creds, &pop, &openOpts) + if err != nil { + t.Fatalf("failed to open pipe for writing %q: %v", fileName, err) + } + defer wfd.DecRef() + + const msg = "geh blau" + checkEmpty(ctx, t, rfd) + checkWrite(ctx, t, wfd, msg) + checkRead(ctx, t, rfd, msg) +} + +func TestNonblockingWriteError(t *testing.T) { + ctx, creds, vfsObj, root := setup(t) + defer root.DecRef() + + // Open the write side as nonblocking, which should return ENXIO. + pop := vfs.PathOperation{ + Root: root, + Start: root, + Pathname: fileName, + FollowFinalSymlink: true, + } + openOpts := vfs.OpenOptions{Flags: linux.O_WRONLY | linux.O_NONBLOCK} + _, err := vfsObj.OpenAt(ctx, creds, &pop, &openOpts) + if err != syserror.ENXIO { + t.Fatalf("expected ENXIO, but got error: %v", err) + } +} + +func TestSingleFD(t *testing.T) { + ctx, creds, vfsObj, root := setup(t) + defer root.DecRef() + + // Open the pipe as readable and writable. + pop := vfs.PathOperation{ + Root: root, + Start: root, + Pathname: fileName, + FollowFinalSymlink: true, + } + openOpts := vfs.OpenOptions{Flags: linux.O_RDWR} + fd, err := vfsObj.OpenAt(ctx, creds, &pop, &openOpts) + if err != nil { + t.Fatalf("failed to open pipe for writing %q: %v", fileName, err) + } + defer fd.DecRef() + + const msg = "forza blu" + checkEmpty(ctx, t, fd) + checkWrite(ctx, t, fd, msg) + checkRead(ctx, t, fd, msg) +} + +// setup creates a VFS with a pipe in the root directory at path fileName. The +// returned VirtualDentry must be DecRef()'d be the caller. It calls t.Fatal +// upon failure. +func setup(t *testing.T) (context.Context, *auth.Credentials, *vfs.VirtualFilesystem, vfs.VirtualDentry) { + ctx := contexttest.Context(t) + creds := auth.CredentialsFromContext(ctx) + + // Create VFS. + vfsObj := vfs.New() + vfsObj.MustRegisterFilesystemType("memfs", FilesystemType{}) + mntns, err := vfsObj.NewMountNamespace(ctx, creds, "", "memfs", &vfs.NewFilesystemOptions{}) + if err != nil { + t.Fatalf("failed to create tmpfs root mount: %v", err) + } + + // Create the pipe. + root := mntns.Root() + pop := vfs.PathOperation{ + Root: root, + Start: root, + Pathname: fileName, + FollowFinalSymlink: true, + } + mknodOpts := vfs.MknodOptions{Mode: linux.ModeNamedPipe | 0644} + if err := vfsObj.MknodAt(ctx, creds, &pop, &mknodOpts); err != nil { + t.Fatalf("failed to create file %q: %v", fileName, err) + } + + // Sanity check: the file pipe exists and has the correct mode. + stat, err := vfsObj.StatAt(ctx, creds, &vfs.PathOperation{ + Root: root, + Start: root, + Pathname: fileName, + FollowFinalSymlink: true, + }, &vfs.StatOptions{}) + if err != nil { + t.Fatalf("stat(%q) failed: %v", fileName, err) + } + if stat.Mode&^linux.S_IFMT != 0644 { + t.Errorf("got wrong permissions (%0o)", stat.Mode) + } + if stat.Mode&linux.S_IFMT != linux.ModeNamedPipe { + t.Errorf("got wrong file type (%0o)", stat.Mode) + } + + return ctx, creds, vfsObj, root +} + +// checkEmpty calls t.Fatal if the pipe in fd is not empty. +func checkEmpty(ctx context.Context, t *testing.T, fd *vfs.FileDescription) { + readData := make([]byte, 1) + dst := usermem.BytesIOSequence(readData) + bytesRead, err := fd.Impl().Read(ctx, dst, vfs.ReadOptions{}) + if err != syserror.ErrWouldBlock { + t.Fatalf("expected ErrWouldBlock reading from empty pipe %q, but got: %v", fileName, err) + } + if bytesRead != 0 { + t.Fatalf("expected to read 0 bytes, but got %d", bytesRead) + } +} + +// checkWrite calls t.Fatal if it fails to write all of msg to fd. +func checkWrite(ctx context.Context, t *testing.T, fd *vfs.FileDescription, msg string) { + writeData := []byte(msg) + src := usermem.BytesIOSequence(writeData) + bytesWritten, err := fd.Impl().Write(ctx, src, vfs.WriteOptions{}) + if err != nil { + t.Fatalf("error writing to pipe %q: %v", fileName, err) + } + if bytesWritten != int64(len(writeData)) { + t.Fatalf("expected to write %d bytes, but wrote %d", len(writeData), bytesWritten) + } +} + +// checkRead calls t.Fatal if it fails to read msg from fd. +func checkRead(ctx context.Context, t *testing.T, fd *vfs.FileDescription, msg string) { + readData := make([]byte, len(msg)) + dst := usermem.BytesIOSequence(readData) + bytesRead, err := fd.Impl().Read(ctx, dst, vfs.ReadOptions{}) + if err != nil { + t.Fatalf("error reading from pipe %q: %v", fileName, err) + } + if bytesRead != int64(len(msg)) { + t.Fatalf("expected to read %d bytes, but got %d", len(msg), bytesRead) + } + if !bytes.Equal(readData, []byte(msg)) { + t.Fatalf("expected to read %q from pipe, but got %q", msg, string(readData)) + } +} diff --git a/pkg/sentry/kernel/pipe/vfs.go b/pkg/sentry/kernel/pipe/vfs.go index 02320b830..6416e0dd8 100644 --- a/pkg/sentry/kernel/pipe/vfs.go +++ b/pkg/sentry/kernel/pipe/vfs.go @@ -182,7 +182,7 @@ func (fd *VFSPipeFD) Release() { } // OnClose implements vfs.FileDescriptionImpl.OnClose. -func (fd *VFSPipeFD) OnClose() error { +func (fd *VFSPipeFD) OnClose(_ context.Context) error { return nil } diff --git a/pkg/sentry/vfs/syscalls.go b/pkg/sentry/vfs/syscalls.go index 23f2b9e08..abde0feaa 100644 --- a/pkg/sentry/vfs/syscalls.go +++ b/pkg/sentry/vfs/syscalls.go @@ -96,6 +96,26 @@ func (vfs *VirtualFilesystem) MkdirAt(ctx context.Context, creds *auth.Credentia } } +// MknodAt creates a file of the given mode at the given path. It returns an +// error from the syserror package. +func (vfs *VirtualFilesystem) MknodAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *MknodOptions) error { + rp, err := vfs.getResolvingPath(creds, pop) + if err != nil { + return nil + } + for { + if err = rp.mount.fs.impl.MknodAt(ctx, rp, *opts); err == nil { + vfs.putResolvingPath(rp) + return nil + } + // Handle mount traversals. + if !rp.handleError(err) { + vfs.putResolvingPath(rp) + return err + } + } +} + // OpenAt returns a FileDescription providing access to the file at the given // path. A reference is taken on the returned FileDescription. func (vfs *VirtualFilesystem) OpenAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *OpenOptions) (*FileDescription, error) { @@ -198,8 +218,6 @@ func (fd *FileDescription) SetStatusFlags(ctx context.Context, flags uint32) err // // - VFS.LinkAt() // -// - VFS.MknodAt() -// // - VFS.ReadlinkAt() // // - VFS.RenameAt() |