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-rw-r--r--pkg/p9/file.go16
-rw-r--r--pkg/sentry/fsimpl/gofer/gofer_state_autogen.go6
-rw-r--r--pkg/sentry/fsimpl/gofer/save_restore.go4
-rw-r--r--pkg/sentry/fsimpl/gofer/special_file.go96
4 files changed, 114 insertions, 8 deletions
diff --git a/pkg/p9/file.go b/pkg/p9/file.go
index 97e0231d6..8d6af2d6b 100644
--- a/pkg/p9/file.go
+++ b/pkg/p9/file.go
@@ -325,6 +325,12 @@ func (*DisallowServerCalls) Renamed(File, string) {
func DefaultMultiGetAttr(start File, names []string) ([]FullStat, error) {
stats := make([]FullStat, 0, len(names))
parent := start
+ closeParent := func() {
+ if parent != start {
+ _ = parent.Close()
+ }
+ }
+ defer closeParent()
mask := AttrMaskAll()
for i, name := range names {
if len(name) == 0 && i == 0 {
@@ -340,15 +346,14 @@ func DefaultMultiGetAttr(start File, names []string) ([]FullStat, error) {
continue
}
qids, child, valid, attr, err := parent.WalkGetAttr([]string{name})
- if parent != start {
- _ = parent.Close()
- }
if err != nil {
if errors.Is(err, unix.ENOENT) {
return stats, nil
}
return nil, err
}
+ closeParent()
+ parent = child
stats = append(stats, FullStat{
QID: qids[0],
Valid: valid,
@@ -357,13 +362,8 @@ func DefaultMultiGetAttr(start File, names []string) ([]FullStat, error) {
if attr.Mode.FileType() != ModeDirectory {
// Doesn't need to continue if entry is not a dir. Including symlinks
// that cannot be followed.
- _ = child.Close()
break
}
- parent = child
- }
- if parent != start {
- _ = parent.Close()
}
return stats, nil
}
diff --git a/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go b/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go
index 11635f249..756def82a 100644
--- a/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go
+++ b/pkg/sentry/fsimpl/gofer/gofer_state_autogen.go
@@ -560,6 +560,8 @@ func (fd *specialFileFD) StateFields() []string {
"off",
"haveBuf",
"buf",
+ "hostFileMapper",
+ "fileRefs",
}
}
@@ -575,6 +577,8 @@ func (fd *specialFileFD) StateSave(stateSinkObject state.Sink) {
stateSinkObject.Save(4, &fd.off)
stateSinkObject.Save(5, &fd.haveBuf)
stateSinkObject.Save(6, &fd.buf)
+ stateSinkObject.Save(7, &fd.hostFileMapper)
+ stateSinkObject.Save(8, &fd.fileRefs)
}
// +checklocksignore
@@ -586,6 +590,8 @@ func (fd *specialFileFD) StateLoad(stateSourceObject state.Source) {
stateSourceObject.Load(4, &fd.off)
stateSourceObject.Load(5, &fd.haveBuf)
stateSourceObject.Load(6, &fd.buf)
+ stateSourceObject.Load(7, &fd.hostFileMapper)
+ stateSourceObject.Load(8, &fd.fileRefs)
stateSourceObject.AfterLoad(fd.afterLoad)
}
diff --git a/pkg/sentry/fsimpl/gofer/save_restore.go b/pkg/sentry/fsimpl/gofer/save_restore.go
index e67422a2f..8dcbc61ed 100644
--- a/pkg/sentry/fsimpl/gofer/save_restore.go
+++ b/pkg/sentry/fsimpl/gofer/save_restore.go
@@ -158,6 +158,10 @@ func (d *dentryPlatformFile) afterLoad() {
// afterLoad is invoked by stateify.
func (fd *specialFileFD) afterLoad() {
fd.handle.fd = -1
+ if fd.hostFileMapper.IsInited() {
+ // Ensure that we don't call fd.hostFileMapper.Init() again.
+ fd.hostFileMapperInitOnce.Do(func() {})
+ }
}
// CompleteRestore implements
diff --git a/pkg/sentry/fsimpl/gofer/special_file.go b/pkg/sentry/fsimpl/gofer/special_file.go
index 8e3c41808..a8d47b65b 100644
--- a/pkg/sentry/fsimpl/gofer/special_file.go
+++ b/pkg/sentry/fsimpl/gofer/special_file.go
@@ -22,9 +22,13 @@ import (
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/fdnotifier"
+ "gvisor.dev/gvisor/pkg/hostarch"
"gvisor.dev/gvisor/pkg/metric"
"gvisor.dev/gvisor/pkg/p9"
+ "gvisor.dev/gvisor/pkg/safemem"
+ "gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
"gvisor.dev/gvisor/pkg/sentry/fsmetric"
+ "gvisor.dev/gvisor/pkg/sentry/memmap"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/usermem"
@@ -74,6 +78,16 @@ type specialFileFD struct {
bufMu sync.Mutex `state:"nosave"`
haveBuf uint32
buf []byte
+
+ // If handle.fd >= 0, hostFileMapper caches mappings of handle.fd, and
+ // hostFileMapperInitOnce is used to initialize it on first use.
+ hostFileMapperInitOnce sync.Once `state:"nosave"`
+ hostFileMapper fsutil.HostFileMapper
+
+ // If handle.fd >= 0, fileRefs counts references on memmap.File offsets.
+ // fileRefs is protected by fileRefsMu.
+ fileRefsMu sync.Mutex `state:"nosave"`
+ fileRefs fsutil.FrameRefSet
}
func newSpecialFileFD(h handle, mnt *vfs.Mount, d *dentry, flags uint32) (*specialFileFD, error) {
@@ -392,3 +406,85 @@ func (fd *specialFileFD) sync(ctx context.Context, forFilesystemSync bool) error
}
return nil
}
+
+// ConfigureMMap implements vfs.FileDescriptionImpl.ConfigureMMap.
+func (fd *specialFileFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
+ if fd.handle.fd < 0 || fd.filesystem().opts.forcePageCache {
+ return linuxerr.ENODEV
+ }
+ // After this point, fd may be used as a memmap.Mappable and memmap.File.
+ fd.hostFileMapperInitOnce.Do(fd.hostFileMapper.Init)
+ return vfs.GenericConfigureMMap(&fd.vfsfd, fd, opts)
+}
+
+// AddMapping implements memmap.Mappable.AddMapping.
+func (fd *specialFileFD) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) error {
+ fd.hostFileMapper.IncRefOn(memmap.MappableRange{offset, offset + uint64(ar.Length())})
+ return nil
+}
+
+// RemoveMapping implements memmap.Mappable.RemoveMapping.
+func (fd *specialFileFD) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) {
+ fd.hostFileMapper.DecRefOn(memmap.MappableRange{offset, offset + uint64(ar.Length())})
+}
+
+// CopyMapping implements memmap.Mappable.CopyMapping.
+func (fd *specialFileFD) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR hostarch.AddrRange, offset uint64, writable bool) error {
+ return fd.AddMapping(ctx, ms, dstAR, offset, writable)
+}
+
+// Translate implements memmap.Mappable.Translate.
+func (fd *specialFileFD) Translate(ctx context.Context, required, optional memmap.MappableRange, at hostarch.AccessType) ([]memmap.Translation, error) {
+ mr := optional
+ if fd.filesystem().opts.limitHostFDTranslation {
+ mr = maxFillRange(required, optional)
+ }
+ return []memmap.Translation{
+ {
+ Source: mr,
+ File: fd,
+ Offset: mr.Start,
+ Perms: hostarch.AnyAccess,
+ },
+ }, nil
+}
+
+// InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.
+func (fd *specialFileFD) InvalidateUnsavable(ctx context.Context) error {
+ return nil
+}
+
+// IncRef implements memmap.File.IncRef.
+func (fd *specialFileFD) IncRef(fr memmap.FileRange) {
+ fd.fileRefsMu.Lock()
+ defer fd.fileRefsMu.Unlock()
+ fd.fileRefs.IncRefAndAccount(fr)
+}
+
+// DecRef implements memmap.File.DecRef.
+func (fd *specialFileFD) DecRef(fr memmap.FileRange) {
+ fd.fileRefsMu.Lock()
+ defer fd.fileRefsMu.Unlock()
+ fd.fileRefs.DecRefAndAccount(fr)
+}
+
+// MapInternal implements memmap.File.MapInternal.
+func (fd *specialFileFD) MapInternal(fr memmap.FileRange, at hostarch.AccessType) (safemem.BlockSeq, error) {
+ fd.requireHostFD()
+ return fd.hostFileMapper.MapInternal(fr, int(fd.handle.fd), at.Write)
+}
+
+// FD implements memmap.File.FD.
+func (fd *specialFileFD) FD() int {
+ fd.requireHostFD()
+ return int(fd.handle.fd)
+}
+
+func (fd *specialFileFD) requireHostFD() {
+ if fd.handle.fd < 0 {
+ // This is possible if fd was successfully mmapped before saving, then
+ // was restored without a host FD. This is unrecoverable: without a
+ // host FD, we can't mmap this file post-restore.
+ panic("gofer.specialFileFD can no longer be memory-mapped without a host FD")
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 22:07:10 +0000