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authorgVisor bot <gvisor-bot@google.com>2020-10-13 19:52:35 +0000
committergVisor bot <gvisor-bot@google.com>2020-10-13 19:52:35 +0000
commit39b186c9816c3898277ac96fd09979f678b6172d (patch)
tree6ebe37e985ec450825532fe838ec37e1a3d9fb31 /pkg/sentry/fs/fsutil
parent543ae5061fa3d31e749b20ff340e86949deda4f1 (diff)
parent1a6948737323436ff5925f2e092fcbbce429deb3 (diff)
Merge release-20200928.0-104-g1a6948737 (automated)
Diffstat (limited to 'pkg/sentry/fs/fsutil')
-rw-r--r--pkg/sentry/fs/fsutil/file_range_set.go21
-rw-r--r--pkg/sentry/fs/fsutil/inode_cached.go4
2 files changed, 20 insertions, 5 deletions
diff --git a/pkg/sentry/fs/fsutil/file_range_set.go b/pkg/sentry/fs/fsutil/file_range_set.go
index 9197aeb88..1dc409d38 100644
--- a/pkg/sentry/fs/fsutil/file_range_set.go
+++ b/pkg/sentry/fs/fsutil/file_range_set.go
@@ -84,7 +84,8 @@ func (seg FileRangeIterator) FileRangeOf(mr memmap.MappableRange) memmap.FileRan
// returns a successful partial read, Fill will call it repeatedly until all
// bytes have been read.) EOF is handled consistently with the requirements of
// mmap(2): bytes after EOF on the same page are zeroed; pages after EOF are
-// invalid.
+// invalid. fileSize is an upper bound on the file's size; bytes after fileSize
+// will be zeroed without calling readAt.
//
// Fill may read offsets outside of required, but will never read offsets
// outside of optional. It returns a non-nil error if any error occurs, even
@@ -94,7 +95,7 @@ func (seg FileRangeIterator) FileRangeOf(mr memmap.MappableRange) memmap.FileRan
// * required.Length() > 0.
// * optional.IsSupersetOf(required).
// * required and optional must be page-aligned.
-func (frs *FileRangeSet) Fill(ctx context.Context, required, optional memmap.MappableRange, mf *pgalloc.MemoryFile, kind usage.MemoryKind, readAt func(ctx context.Context, dsts safemem.BlockSeq, offset uint64) (uint64, error)) error {
+func (frs *FileRangeSet) Fill(ctx context.Context, required, optional memmap.MappableRange, fileSize uint64, mf *pgalloc.MemoryFile, kind usage.MemoryKind, readAt func(ctx context.Context, dsts safemem.BlockSeq, offset uint64) (uint64, error)) error {
gap := frs.LowerBoundGap(required.Start)
for gap.Ok() && gap.Start() < required.End {
if gap.Range().Length() == 0 {
@@ -107,7 +108,21 @@ func (frs *FileRangeSet) Fill(ctx context.Context, required, optional memmap.Map
fr, err := mf.AllocateAndFill(gr.Length(), kind, safemem.ReaderFunc(func(dsts safemem.BlockSeq) (uint64, error) {
var done uint64
for !dsts.IsEmpty() {
- n, err := readAt(ctx, dsts, gr.Start+done)
+ n, err := func() (uint64, error) {
+ off := gr.Start + done
+ if off >= fileSize {
+ return 0, io.EOF
+ }
+ if off+dsts.NumBytes() > fileSize {
+ rd := fileSize - off
+ n, err := readAt(ctx, dsts.TakeFirst64(rd), off)
+ if n == rd && err == nil {
+ return n, io.EOF
+ }
+ return n, err
+ }
+ return readAt(ctx, dsts, off)
+ }()
done += n
dsts = dsts.DropFirst64(n)
if err != nil {
diff --git a/pkg/sentry/fs/fsutil/inode_cached.go b/pkg/sentry/fs/fsutil/inode_cached.go
index 85a23432b..82eda3e43 100644
--- a/pkg/sentry/fs/fsutil/inode_cached.go
+++ b/pkg/sentry/fs/fsutil/inode_cached.go
@@ -644,7 +644,7 @@ func (rw *inodeReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) {
End: fs.OffsetPageEnd(int64(gapMR.End)),
}
optMR := gap.Range()
- err := rw.c.cache.Fill(rw.ctx, reqMR, maxFillRange(reqMR, optMR), mem, usage.PageCache, rw.c.backingFile.ReadToBlocksAt)
+ err := rw.c.cache.Fill(rw.ctx, reqMR, maxFillRange(reqMR, optMR), uint64(rw.c.attr.Size), mem, usage.PageCache, rw.c.backingFile.ReadToBlocksAt)
mem.MarkEvictable(rw.c, pgalloc.EvictableRange{optMR.Start, optMR.End})
seg, gap = rw.c.cache.Find(uint64(rw.offset))
if !seg.Ok() {
@@ -870,7 +870,7 @@ func (c *CachingInodeOperations) Translate(ctx context.Context, required, option
}
mf := c.mfp.MemoryFile()
- cerr := c.cache.Fill(ctx, required, maxFillRange(required, optional), mf, usage.PageCache, c.backingFile.ReadToBlocksAt)
+ cerr := c.cache.Fill(ctx, required, maxFillRange(required, optional), uint64(c.attr.Size), mf, usage.PageCache, c.backingFile.ReadToBlocksAt)
var ts []memmap.Translation
var translatedEnd uint64