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-rw-r--r--pkg/p9/handlers.go18
-rw-r--r--pkg/p9/p9.go4
-rw-r--r--pkg/p9/version.go8
-rw-r--r--pkg/sentry/fs/flags.go7
-rwxr-xr-xpkg/sentry/fs/fs_state_autogen.go2
-rw-r--r--pkg/sentry/fs/gofer/file_state.go8
-rw-r--r--pkg/sentry/fs/gofer/handles.go5
-rw-r--r--pkg/sentry/fs/gofer/inode.go18
-rw-r--r--pkg/sentry/syscalls/linux/flags.go1
9 files changed, 49 insertions, 22 deletions
diff --git a/pkg/p9/handlers.go b/pkg/p9/handlers.go
index ba9a55d6d..51869c7d6 100644
--- a/pkg/p9/handlers.go
+++ b/pkg/p9/handlers.go
@@ -272,15 +272,15 @@ func (t *Tlopen) handle(cs *connState) message {
return newErr(syscall.EINVAL)
}
- // Are flags valid?
- flags := t.Flags &^ OpenFlagsIgnoreMask
- if flags&^OpenFlagsModeMask != 0 {
- return newErr(syscall.EINVAL)
- }
-
- // Is this an attempt to open a directory as writable? Don't accept.
- if ref.mode.IsDir() && flags != ReadOnly {
- return newErr(syscall.EINVAL)
+ if ref.mode.IsDir() {
+ // Directory must be opened ReadOnly.
+ if t.Flags&OpenFlagsModeMask != ReadOnly {
+ return newErr(syscall.EISDIR)
+ }
+ // Directory not truncatable.
+ if t.Flags&OpenTruncate != 0 {
+ return newErr(syscall.EISDIR)
+ }
}
var (
diff --git a/pkg/p9/p9.go b/pkg/p9/p9.go
index 415200d60..d3090535a 100644
--- a/pkg/p9/p9.go
+++ b/pkg/p9/p9.go
@@ -47,10 +47,6 @@ const (
// OpenTruncate is a Tlopen flag indicating that the opened file should be
// truncated.
OpenTruncate OpenFlags = 01000
-
- // OpenFlagsIgnoreMask is a list of OpenFlags mode bits that are ignored for Tlopen.
- // Note that syscall.O_LARGEFILE is set to zero, use value from Linux fcntl.h.
- OpenFlagsIgnoreMask OpenFlags = syscall.O_DIRECTORY | syscall.O_NOATIME | 0100000
)
// ConnectFlags is the mode passed to Connect operations.
diff --git a/pkg/p9/version.go b/pkg/p9/version.go
index f1ffdd23a..36a694c58 100644
--- a/pkg/p9/version.go
+++ b/pkg/p9/version.go
@@ -26,7 +26,7 @@ const (
//
// Clients are expected to start requesting this version number and
// to continuously decrement it until a Tversion request succeeds.
- highestSupportedVersion uint32 = 8
+ highestSupportedVersion uint32 = 9
// lowestSupportedVersion is the lowest supported version X in a
// version string of the format 9P2000.L.Google.X.
@@ -155,3 +155,9 @@ func versionSupportsTallocate(v uint32) bool {
func versionSupportsFlipcall(v uint32) bool {
return v >= 8
}
+
+// VersionSupportsOpenTruncateFlag returns true if version v supports
+// passing the OpenTruncate flag to Tlopen.
+func VersionSupportsOpenTruncateFlag(v uint32) bool {
+ return v >= 9
+}
diff --git a/pkg/sentry/fs/flags.go b/pkg/sentry/fs/flags.go
index 0fab876a9..4338ae1fa 100644
--- a/pkg/sentry/fs/flags.go
+++ b/pkg/sentry/fs/flags.go
@@ -64,6 +64,10 @@ type FileFlags struct {
// NonSeekable indicates that file.offset isn't used.
NonSeekable bool
+
+ // Truncate indicates that the file should be truncated before opened.
+ // This is only applicable if the file is regular.
+ Truncate bool
}
// SettableFileFlags is a subset of FileFlags above that can be changed
@@ -118,6 +122,9 @@ func (f FileFlags) ToLinux() (mask uint) {
if f.LargeFile {
mask |= linux.O_LARGEFILE
}
+ if f.Truncate {
+ mask |= linux.O_TRUNC
+ }
switch {
case f.Read && f.Write:
diff --git a/pkg/sentry/fs/fs_state_autogen.go b/pkg/sentry/fs/fs_state_autogen.go
index 5ea2669e6..a6820867d 100755
--- a/pkg/sentry/fs/fs_state_autogen.go
+++ b/pkg/sentry/fs/fs_state_autogen.go
@@ -353,6 +353,7 @@ func (x *FileFlags) save(m state.Map) {
m.Save("Async", &x.Async)
m.Save("LargeFile", &x.LargeFile)
m.Save("NonSeekable", &x.NonSeekable)
+ m.Save("Truncate", &x.Truncate)
}
func (x *FileFlags) afterLoad() {}
@@ -370,6 +371,7 @@ func (x *FileFlags) load(m state.Map) {
m.Load("Async", &x.Async)
m.Load("LargeFile", &x.LargeFile)
m.Load("NonSeekable", &x.NonSeekable)
+ m.Load("Truncate", &x.Truncate)
}
func (x *Inode) beforeSave() {}
diff --git a/pkg/sentry/fs/gofer/file_state.go b/pkg/sentry/fs/gofer/file_state.go
index c2fbb4be9..bb8312849 100644
--- a/pkg/sentry/fs/gofer/file_state.go
+++ b/pkg/sentry/fs/gofer/file_state.go
@@ -28,8 +28,14 @@ func (f *fileOperations) afterLoad() {
// Manually load the open handles.
var err error
+
+ // The file may have been opened with Truncate, but we don't
+ // want to re-open it with Truncate or we will lose data.
+ flags := f.flags
+ flags.Truncate = false
+
// TODO(b/38173783): Context is not plumbed to save/restore.
- f.handles, err = f.inodeOperations.fileState.getHandles(context.Background(), f.flags, f.inodeOperations.cachingInodeOps)
+ f.handles, err = f.inodeOperations.fileState.getHandles(context.Background(), flags, f.inodeOperations.cachingInodeOps)
if err != nil {
return fmt.Errorf("failed to re-open handle: %v", err)
}
diff --git a/pkg/sentry/fs/gofer/handles.go b/pkg/sentry/fs/gofer/handles.go
index 39c8ec33d..b86c49b39 100644
--- a/pkg/sentry/fs/gofer/handles.go
+++ b/pkg/sentry/fs/gofer/handles.go
@@ -64,7 +64,7 @@ func (h *handles) DecRef() {
})
}
-func newHandles(ctx context.Context, file contextFile, flags fs.FileFlags) (*handles, error) {
+func newHandles(ctx context.Context, client *p9.Client, file contextFile, flags fs.FileFlags) (*handles, error) {
_, newFile, err := file.walk(ctx, nil)
if err != nil {
return nil, err
@@ -81,6 +81,9 @@ func newHandles(ctx context.Context, file contextFile, flags fs.FileFlags) (*han
default:
panic("impossible fs.FileFlags")
}
+ if flags.Truncate && p9.VersionSupportsOpenTruncateFlag(client.Version()) {
+ p9flags |= p9.OpenTruncate
+ }
hostFile, _, _, err := newFile.open(ctx, p9flags)
if err != nil {
diff --git a/pkg/sentry/fs/gofer/inode.go b/pkg/sentry/fs/gofer/inode.go
index 99910388f..4237bf353 100644
--- a/pkg/sentry/fs/gofer/inode.go
+++ b/pkg/sentry/fs/gofer/inode.go
@@ -180,7 +180,7 @@ func (i *inodeFileState) setSharedHandlesLocked(flags fs.FileFlags, h *handles)
// given flags.
func (i *inodeFileState) getHandles(ctx context.Context, flags fs.FileFlags, cache *fsutil.CachingInodeOperations) (*handles, error) {
if !i.canShareHandles() {
- return newHandles(ctx, i.file, flags)
+ return newHandles(ctx, i.s.client, i.file, flags)
}
i.handlesMu.Lock()
@@ -201,19 +201,25 @@ func (i *inodeFileState) getHandles(ctx context.Context, flags fs.FileFlags, cac
// whether previously open read handle was recreated. Host mappings must be
// invalidated if so.
func (i *inodeFileState) getHandlesLocked(ctx context.Context, flags fs.FileFlags) (*handles, bool, error) {
- // Do we already have usable shared handles?
- if flags.Write {
+ // Check if we are able to use cached handles.
+ if flags.Truncate && p9.VersionSupportsOpenTruncateFlag(i.s.client.Version()) {
+ // If we are truncating (and the gofer supports it), then we
+ // always need a new handle. Don't return one from the cache.
+ } else if flags.Write {
if i.writeHandles != nil && (i.writeHandlesRW || !flags.Read) {
+ // File is opened for writing, and we have cached write
+ // handles that we can use.
i.writeHandles.IncRef()
return i.writeHandles, false, nil
}
} else if i.readHandles != nil {
+ // File is opened for reading and we have cached handles.
i.readHandles.IncRef()
return i.readHandles, false, nil
}
- // No; get new handles and cache them for future sharing.
- h, err := newHandles(ctx, i.file, flags)
+ // Get new handles and cache them for future sharing.
+ h, err := newHandles(ctx, i.s.client, i.file, flags)
if err != nil {
return nil, false, err
}
@@ -239,7 +245,7 @@ func (i *inodeFileState) recreateReadHandles(ctx context.Context, writer *handle
if !flags.Read {
// Writer can't be used for read, must create a new handle.
var err error
- h, err = newHandles(ctx, i.file, fs.FileFlags{Read: true})
+ h, err = newHandles(ctx, i.s.client, i.file, fs.FileFlags{Read: true})
if err != nil {
return err
}
diff --git a/pkg/sentry/syscalls/linux/flags.go b/pkg/sentry/syscalls/linux/flags.go
index 444f2b004..07961dad9 100644
--- a/pkg/sentry/syscalls/linux/flags.go
+++ b/pkg/sentry/syscalls/linux/flags.go
@@ -50,5 +50,6 @@ func linuxToFlags(mask uint) fs.FileFlags {
Directory: mask&linux.O_DIRECTORY != 0,
Async: mask&linux.O_ASYNC != 0,
LargeFile: mask&linux.O_LARGEFILE != 0,
+ Truncate: mask&linux.O_TRUNC != 0,
}
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-02 20:23:07 +0000