diff options
author | gVisor bot <gvisor-bot@google.com> | 2019-10-16 22:20:51 +0000 |
---|---|---|
committer | gVisor bot <gvisor-bot@google.com> | 2019-10-16 22:20:51 +0000 |
commit | a02f8d0dbefc8a56940a579f07ac1c35be92a112 (patch) | |
tree | 8e44280b5dfecea49eca930c60bfeb4cbfe03e77 /pkg/sentry/fs/fsutil | |
parent | d8af87b44fcae3f7666005fa0e54d242c3708699 (diff) | |
parent | 9fb562234e7858dbc60e8771f851629464edf205 (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.go | 26 | ||||
-rw-r--r-- | pkg/sentry/fs/fsutil/host_mappable.go | 19 | ||||
-rw-r--r-- | pkg/sentry/fs/fsutil/inode_cached.go | 18 |
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 |