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authorgVisor bot <gvisor-bot@google.com>2019-10-16 22:20:51 +0000
committergVisor bot <gvisor-bot@google.com>2019-10-16 22:20:51 +0000
commita02f8d0dbefc8a56940a579f07ac1c35be92a112 (patch)
tree8e44280b5dfecea49eca930c60bfeb4cbfe03e77 /pkg/sentry/fs/fsutil
parentd8af87b44fcae3f7666005fa0e54d242c3708699 (diff)
parent9fb562234e7858dbc60e8771f851629464edf205 (diff)
Merge release-20190806.1-281-g9fb5622 (automated)
Diffstat (limited to 'pkg/sentry/fs/fsutil')
-rw-r--r--pkg/sentry/fs/fsutil/host_file_mapper.go26
-rw-r--r--pkg/sentry/fs/fsutil/host_mappable.go19
-rw-r--r--pkg/sentry/fs/fsutil/inode_cached.go18
3 files changed, 61 insertions, 2 deletions
diff --git a/pkg/sentry/fs/fsutil/host_file_mapper.go b/pkg/sentry/fs/fsutil/host_file_mapper.go
index e239f12a5..b06a71cc2 100644
--- a/pkg/sentry/fs/fsutil/host_file_mapper.go
+++ b/pkg/sentry/fs/fsutil/host_file_mapper.go
@@ -209,3 +209,29 @@ func (f *HostFileMapper) unmapAndRemoveLocked(chunkStart uint64, m mapping) {
}
delete(f.mappings, chunkStart)
}
+
+// RegenerateMappings must be called when the file description mapped by f
+// changes, to replace existing mappings of the previous file description.
+func (f *HostFileMapper) RegenerateMappings(fd int) error {
+ f.mapsMu.Lock()
+ defer f.mapsMu.Unlock()
+
+ for chunkStart, m := range f.mappings {
+ prot := syscall.PROT_READ
+ if m.writable {
+ prot |= syscall.PROT_WRITE
+ }
+ _, _, errno := syscall.Syscall6(
+ syscall.SYS_MMAP,
+ m.addr,
+ chunkSize,
+ uintptr(prot),
+ syscall.MAP_SHARED|syscall.MAP_FIXED,
+ uintptr(fd),
+ uintptr(chunkStart))
+ if errno != 0 {
+ return errno
+ }
+ }
+ return nil
+}
diff --git a/pkg/sentry/fs/fsutil/host_mappable.go b/pkg/sentry/fs/fsutil/host_mappable.go
index 693625ddc..30475f340 100644
--- a/pkg/sentry/fs/fsutil/host_mappable.go
+++ b/pkg/sentry/fs/fsutil/host_mappable.go
@@ -100,13 +100,30 @@ func (h *HostMappable) Translate(ctx context.Context, required, optional memmap.
}
// InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.
-func (h *HostMappable) InvalidateUnsavable(ctx context.Context) error {
+func (h *HostMappable) InvalidateUnsavable(_ context.Context) error {
h.mu.Lock()
h.mappings.InvalidateAll(memmap.InvalidateOpts{})
h.mu.Unlock()
return nil
}
+// NotifyChangeFD must be called after the file description represented by
+// CachedFileObject.FD() changes.
+func (h *HostMappable) NotifyChangeFD() error {
+ // Update existing sentry mappings to refer to the new file description.
+ if err := h.hostFileMapper.RegenerateMappings(h.backingFile.FD()); err != nil {
+ return err
+ }
+
+ // Shoot down existing application mappings of the old file description;
+ // they will be remapped with the new file description on demand.
+ h.mu.Lock()
+ defer h.mu.Unlock()
+
+ h.mappings.InvalidateAll(memmap.InvalidateOpts{})
+ return nil
+}
+
// MapInternal implements platform.File.MapInternal.
func (h *HostMappable) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
return h.hostFileMapper.MapInternal(fr, h.backingFile.FD(), at.Write)
diff --git a/pkg/sentry/fs/fsutil/inode_cached.go b/pkg/sentry/fs/fsutil/inode_cached.go
index dd80757dc..798920d18 100644
--- a/pkg/sentry/fs/fsutil/inode_cached.go
+++ b/pkg/sentry/fs/fsutil/inode_cached.go
@@ -959,6 +959,23 @@ func (c *CachingInodeOperations) InvalidateUnsavable(ctx context.Context) error
return nil
}
+// NotifyChangeFD must be called after the file description represented by
+// CachedFileObject.FD() changes.
+func (c *CachingInodeOperations) NotifyChangeFD() error {
+ // Update existing sentry mappings to refer to the new file description.
+ if err := c.hostFileMapper.RegenerateMappings(c.backingFile.FD()); err != nil {
+ return err
+ }
+
+ // Shoot down existing application mappings of the old file description;
+ // they will be remapped with the new file description on demand.
+ c.mapsMu.Lock()
+ defer c.mapsMu.Unlock()
+
+ c.mappings.InvalidateAll(memmap.InvalidateOpts{})
+ return nil
+}
+
// Evict implements pgalloc.EvictableMemoryUser.Evict.
func (c *CachingInodeOperations) Evict(ctx context.Context, er pgalloc.EvictableRange) {
c.mapsMu.Lock()
@@ -1027,7 +1044,6 @@ func (c *CachingInodeOperations) DecRef(fr platform.FileRange) {
}
c.refs.MergeAdjacent(fr)
c.dataMu.Unlock()
-
}
// MapInternal implements platform.File.MapInternal. This is used when we