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-rw-r--r--pkg/sentry/fs/fsutil/frame_ref_set.go40
-rw-r--r--pkg/sentry/fsimpl/gofer/BUILD1
-rw-r--r--pkg/sentry/fsimpl/gofer/gofer.go4
-rw-r--r--pkg/sentry/fsimpl/gofer/pagemath.go31
-rw-r--r--pkg/sentry/fsimpl/gofer/regular_file.go47
-rw-r--r--pkg/sentry/fsimpl/host/BUILD4
-rw-r--r--pkg/sentry/fsimpl/host/host.go70
-rw-r--r--pkg/sentry/fsimpl/host/mmap.go132
-rw-r--r--pkg/usermem/addr.go17
9 files changed, 254 insertions, 92 deletions
diff --git a/pkg/sentry/fs/fsutil/frame_ref_set.go b/pkg/sentry/fs/fsutil/frame_ref_set.go
index 6564fd0c6..dd6f5aba6 100644
--- a/pkg/sentry/fs/fsutil/frame_ref_set.go
+++ b/pkg/sentry/fs/fsutil/frame_ref_set.go
@@ -18,6 +18,7 @@ import (
"math"
"gvisor.dev/gvisor/pkg/sentry/platform"
+ "gvisor.dev/gvisor/pkg/sentry/usage"
)
// FrameRefSetFunctions implements segment.Functions for FrameRefSet.
@@ -49,3 +50,42 @@ func (FrameRefSetFunctions) Merge(_ platform.FileRange, val1 uint64, _ platform.
func (FrameRefSetFunctions) Split(_ platform.FileRange, val uint64, _ uint64) (uint64, uint64) {
return val, val
}
+
+// IncRefAndAccount adds a reference on the range fr. All newly inserted segments
+// are accounted as host page cache memory mappings.
+func (refs *FrameRefSet) IncRefAndAccount(fr platform.FileRange) {
+ seg, gap := refs.Find(fr.Start)
+ for {
+ switch {
+ case seg.Ok() && seg.Start() < fr.End:
+ seg = refs.Isolate(seg, fr)
+ seg.SetValue(seg.Value() + 1)
+ seg, gap = seg.NextNonEmpty()
+ case gap.Ok() && gap.Start() < fr.End:
+ newRange := gap.Range().Intersect(fr)
+ usage.MemoryAccounting.Inc(newRange.Length(), usage.Mapped)
+ seg, gap = refs.InsertWithoutMerging(gap, newRange, 1).NextNonEmpty()
+ default:
+ refs.MergeAdjacent(fr)
+ return
+ }
+ }
+}
+
+// DecRefAndAccount removes a reference on the range fr and untracks segments
+// that are removed from memory accounting.
+func (refs *FrameRefSet) DecRefAndAccount(fr platform.FileRange) {
+ seg := refs.FindSegment(fr.Start)
+
+ for seg.Ok() && seg.Start() < fr.End {
+ seg = refs.Isolate(seg, fr)
+ if old := seg.Value(); old == 1 {
+ usage.MemoryAccounting.Dec(seg.Range().Length(), usage.Mapped)
+ seg = refs.Remove(seg).NextSegment()
+ } else {
+ seg.SetValue(old - 1)
+ seg = seg.NextSegment()
+ }
+ }
+ refs.MergeAdjacent(fr)
+}
diff --git a/pkg/sentry/fsimpl/gofer/BUILD b/pkg/sentry/fsimpl/gofer/BUILD
index 5ce82b793..67e916525 100644
--- a/pkg/sentry/fsimpl/gofer/BUILD
+++ b/pkg/sentry/fsimpl/gofer/BUILD
@@ -36,7 +36,6 @@ go_library(
"gofer.go",
"handle.go",
"p9file.go",
- "pagemath.go",
"regular_file.go",
"socket.go",
"special_file.go",
diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go
index ebf063a58..6295f6b54 100644
--- a/pkg/sentry/fsimpl/gofer/gofer.go
+++ b/pkg/sentry/fsimpl/gofer/gofer.go
@@ -928,8 +928,8 @@ func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *lin
// so we can't race with Write or another truncate.)
d.dataMu.Unlock()
if d.size < oldSize {
- oldpgend := pageRoundUp(oldSize)
- newpgend := pageRoundUp(d.size)
+ oldpgend, _ := usermem.PageRoundUp(oldSize)
+ newpgend, _ := usermem.PageRoundUp(d.size)
if oldpgend != newpgend {
d.mapsMu.Lock()
d.mappings.Invalidate(memmap.MappableRange{newpgend, oldpgend}, memmap.InvalidateOpts{
diff --git a/pkg/sentry/fsimpl/gofer/pagemath.go b/pkg/sentry/fsimpl/gofer/pagemath.go
deleted file mode 100644
index 847cb0784..000000000
--- a/pkg/sentry/fsimpl/gofer/pagemath.go
+++ /dev/null
@@ -1,31 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package gofer
-
-import (
- "gvisor.dev/gvisor/pkg/usermem"
-)
-
-// This are equivalent to usermem.Addr.RoundDown/Up, but without the
-// potentially truncating conversion to usermem.Addr. This is necessary because
-// there is no way to define generic "PageRoundDown/Up" functions in Go.
-
-func pageRoundDown(x uint64) uint64 {
- return x &^ (usermem.PageSize - 1)
-}
-
-func pageRoundUp(x uint64) uint64 {
- return pageRoundDown(x + usermem.PageSize - 1)
-}
diff --git a/pkg/sentry/fsimpl/gofer/regular_file.go b/pkg/sentry/fsimpl/gofer/regular_file.go
index 857f7c74e..0d10cf7ac 100644
--- a/pkg/sentry/fsimpl/gofer/regular_file.go
+++ b/pkg/sentry/fsimpl/gofer/regular_file.go
@@ -148,9 +148,9 @@ func (fd *regularFileFD) PWrite(ctx context.Context, src usermem.IOSequence, off
return 0, err
}
// Remove touched pages from the cache.
- pgstart := pageRoundDown(uint64(offset))
- pgend := pageRoundUp(uint64(offset + src.NumBytes()))
- if pgend < pgstart {
+ pgstart := usermem.PageRoundDown(uint64(offset))
+ pgend, ok := usermem.PageRoundUp(uint64(offset + src.NumBytes()))
+ if !ok {
return 0, syserror.EINVAL
}
mr := memmap.MappableRange{pgstart, pgend}
@@ -306,9 +306,10 @@ func (rw *dentryReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error)
if fillCache {
// Read into the cache, then re-enter the loop to read from the
// cache.
+ gapEnd, _ := usermem.PageRoundUp(gapMR.End)
reqMR := memmap.MappableRange{
- Start: pageRoundDown(gapMR.Start),
- End: pageRoundUp(gapMR.End),
+ Start: usermem.PageRoundDown(gapMR.Start),
+ End: gapEnd,
}
optMR := gap.Range()
err := rw.d.cache.Fill(rw.ctx, reqMR, maxFillRange(reqMR, optMR), mf, usage.PageCache, rw.d.handle.readToBlocksAt)
@@ -671,7 +672,7 @@ func (d *dentry) Translate(ctx context.Context, required, optional memmap.Mappab
// Constrain translations to d.size (rounded up) to prevent translation to
// pages that may be concurrently truncated.
- pgend := pageRoundUp(d.size)
+ pgend, _ := usermem.PageRoundUp(d.size)
var beyondEOF bool
if required.End > pgend {
if required.Start >= pgend {
@@ -818,43 +819,15 @@ type dentryPlatformFile struct {
// IncRef implements platform.File.IncRef.
func (d *dentryPlatformFile) IncRef(fr platform.FileRange) {
d.dataMu.Lock()
- seg, gap := d.fdRefs.Find(fr.Start)
- for {
- switch {
- case seg.Ok() && seg.Start() < fr.End:
- seg = d.fdRefs.Isolate(seg, fr)
- seg.SetValue(seg.Value() + 1)
- seg, gap = seg.NextNonEmpty()
- case gap.Ok() && gap.Start() < fr.End:
- newRange := gap.Range().Intersect(fr)
- usage.MemoryAccounting.Inc(newRange.Length(), usage.Mapped)
- seg, gap = d.fdRefs.InsertWithoutMerging(gap, newRange, 1).NextNonEmpty()
- default:
- d.fdRefs.MergeAdjacent(fr)
- d.dataMu.Unlock()
- return
- }
- }
+ d.fdRefs.IncRefAndAccount(fr)
+ d.dataMu.Unlock()
}
// DecRef implements platform.File.DecRef.
func (d *dentryPlatformFile) DecRef(fr platform.FileRange) {
d.dataMu.Lock()
- seg := d.fdRefs.FindSegment(fr.Start)
-
- for seg.Ok() && seg.Start() < fr.End {
- seg = d.fdRefs.Isolate(seg, fr)
- if old := seg.Value(); old == 1 {
- usage.MemoryAccounting.Dec(seg.Range().Length(), usage.Mapped)
- seg = d.fdRefs.Remove(seg).NextSegment()
- } else {
- seg.SetValue(old - 1)
- seg = seg.NextSegment()
- }
- }
- d.fdRefs.MergeAdjacent(fr)
+ d.fdRefs.DecRefAndAccount(fr)
d.dataMu.Unlock()
-
}
// MapInternal implements platform.File.MapInternal.
diff --git a/pkg/sentry/fsimpl/host/BUILD b/pkg/sentry/fsimpl/host/BUILD
index 39509f703..ca0fe6d2b 100644
--- a/pkg/sentry/fsimpl/host/BUILD
+++ b/pkg/sentry/fsimpl/host/BUILD
@@ -8,6 +8,7 @@ go_library(
"control.go",
"host.go",
"ioctl_unsafe.go",
+ "mmap.go",
"socket.go",
"socket_iovec.go",
"socket_unsafe.go",
@@ -23,12 +24,15 @@ go_library(
"//pkg/fspath",
"//pkg/log",
"//pkg/refs",
+ "//pkg/safemem",
"//pkg/sentry/arch",
+ "//pkg/sentry/fs/fsutil",
"//pkg/sentry/fsimpl/kernfs",
"//pkg/sentry/hostfd",
"//pkg/sentry/kernel",
"//pkg/sentry/kernel/auth",
"//pkg/sentry/memmap",
+ "//pkg/sentry/platform",
"//pkg/sentry/socket/control",
"//pkg/sentry/socket/unix",
"//pkg/sentry/socket/unix/transport",
diff --git a/pkg/sentry/fsimpl/host/host.go b/pkg/sentry/fsimpl/host/host.go
index 8caf55a1b..65981197d 100644
--- a/pkg/sentry/fsimpl/host/host.go
+++ b/pkg/sentry/fsimpl/host/host.go
@@ -86,15 +86,16 @@ func NewFD(ctx context.Context, mnt *vfs.Mount, hostFD int, opts *NewFDOptions)
i := &inode{
hostFD: hostFD,
- seekable: seekable,
+ ino: fs.NextIno(),
isTTY: opts.IsTTY,
- canMap: canMap(uint32(fileType)),
wouldBlock: wouldBlock(uint32(fileType)),
- ino: fs.NextIno(),
+ seekable: seekable,
// For simplicity, set offset to 0. Technically, we should use the existing
// offset on the host if the file is seekable.
offset: 0,
+ canMap: canMap(uint32(fileType)),
}
+ i.pf.inode = i
// Non-seekable files can't be memory mapped, assert this.
if !i.seekable && i.canMap {
@@ -189,11 +190,15 @@ type inode struct {
// This field is initialized at creation time and is immutable.
hostFD int
- // wouldBlock is true if the host FD would return EWOULDBLOCK for
- // operations that would block.
+ // ino is an inode number unique within this filesystem.
//
// This field is initialized at creation time and is immutable.
- wouldBlock bool
+ ino uint64
+
+ // isTTY is true if this file represents a TTY.
+ //
+ // This field is initialized at creation time and is immutable.
+ isTTY bool
// seekable is false if the host fd points to a file representing a stream,
// e.g. a socket or a pipe. Such files are not seekable and can return
@@ -202,29 +207,36 @@ type inode struct {
// This field is initialized at creation time and is immutable.
seekable bool
- // isTTY is true if this file represents a TTY.
+ // offsetMu protects offset.
+ offsetMu sync.Mutex
+
+ // offset specifies the current file offset. It is only meaningful when
+ // seekable is true.
+ offset int64
+
+ // wouldBlock is true if the host FD would return EWOULDBLOCK for
+ // operations that would block.
//
// This field is initialized at creation time and is immutable.
- isTTY bool
+ wouldBlock bool
+
+ // Event queue for blocking operations.
+ queue waiter.Queue
// canMap specifies whether we allow the file to be memory mapped.
//
// This field is initialized at creation time and is immutable.
canMap bool
- // ino is an inode number unique within this filesystem.
- //
- // This field is initialized at creation time and is immutable.
- ino uint64
-
- // offsetMu protects offset.
- offsetMu sync.Mutex
+ // mapsMu protects mappings.
+ mapsMu sync.Mutex
- // offset specifies the current file offset.
- offset int64
+ // If canMap is true, mappings tracks mappings of hostFD into
+ // memmap.MappingSpaces.
+ mappings memmap.MappingSet
- // Event queue for blocking operations.
- queue waiter.Queue
+ // pf implements platform.File for mappings of hostFD.
+ pf inodePlatformFile
}
// CheckPermissions implements kernfs.Inode.
@@ -388,6 +400,21 @@ func (i *inode) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Cre
if err := syscall.Ftruncate(i.hostFD, int64(s.Size)); err != nil {
return err
}
+ oldSize := uint64(hostStat.Size)
+ if s.Size < oldSize {
+ oldpgend, _ := usermem.PageRoundUp(oldSize)
+ newpgend, _ := usermem.PageRoundUp(s.Size)
+ if oldpgend != newpgend {
+ i.mapsMu.Lock()
+ i.mappings.Invalidate(memmap.MappableRange{newpgend, oldpgend}, memmap.InvalidateOpts{
+ // Compare Linux's mm/truncate.c:truncate_setsize() =>
+ // truncate_pagecache() =>
+ // mm/memory.c:unmap_mapping_range(evencows=1).
+ InvalidatePrivate: true,
+ })
+ i.mapsMu.Unlock()
+ }
+ }
}
if m&(linux.STATX_ATIME|linux.STATX_MTIME) != 0 {
ts := [2]syscall.Timespec{
@@ -666,8 +693,9 @@ func (f *fileDescription) ConfigureMMap(_ context.Context, opts *memmap.MMapOpts
if !f.inode.canMap {
return syserror.ENODEV
}
- // TODO(gvisor.dev/issue/1672): Implement ConfigureMMap and Mappable interface.
- return syserror.ENODEV
+ i := f.inode
+ i.pf.fileMapperInitOnce.Do(i.pf.fileMapper.Init)
+ return vfs.GenericConfigureMMap(&f.vfsfd, i, opts)
}
// EventRegister implements waiter.Waitable.EventRegister.
diff --git a/pkg/sentry/fsimpl/host/mmap.go b/pkg/sentry/fsimpl/host/mmap.go
new file mode 100644
index 000000000..8545a82f0
--- /dev/null
+++ b/pkg/sentry/fsimpl/host/mmap.go
@@ -0,0 +1,132 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package host
+
+import (
+ "gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/safemem"
+ "gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
+ "gvisor.dev/gvisor/pkg/sentry/memmap"
+ "gvisor.dev/gvisor/pkg/sentry/platform"
+ "gvisor.dev/gvisor/pkg/sync"
+ "gvisor.dev/gvisor/pkg/usermem"
+)
+
+// inodePlatformFile implements platform.File. It exists solely because inode
+// cannot implement both kernfs.Inode.IncRef and platform.File.IncRef.
+//
+// inodePlatformFile should only be used if inode.canMap is true.
+type inodePlatformFile struct {
+ *inode
+
+ // fdRefsMu protects fdRefs.
+ fdRefsMu sync.Mutex
+
+ // fdRefs counts references on platform.File offsets. It is used solely for
+ // memory accounting.
+ fdRefs fsutil.FrameRefSet
+
+ // fileMapper caches mappings of the host file represented by this inode.
+ fileMapper fsutil.HostFileMapper
+
+ // fileMapperInitOnce is used to lazily initialize fileMapper.
+ fileMapperInitOnce sync.Once
+}
+
+// IncRef implements platform.File.IncRef.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inodePlatformFile) IncRef(fr platform.FileRange) {
+ i.fdRefsMu.Lock()
+ i.fdRefs.IncRefAndAccount(fr)
+ i.fdRefsMu.Unlock()
+}
+
+// DecRef implements platform.File.DecRef.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inodePlatformFile) DecRef(fr platform.FileRange) {
+ i.fdRefsMu.Lock()
+ i.fdRefs.DecRefAndAccount(fr)
+ i.fdRefsMu.Unlock()
+}
+
+// MapInternal implements platform.File.MapInternal.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inodePlatformFile) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
+ return i.fileMapper.MapInternal(fr, i.hostFD, at.Write)
+}
+
+// FD implements platform.File.FD.
+func (i *inodePlatformFile) FD() int {
+ return i.hostFD
+}
+
+// AddMapping implements memmap.Mappable.AddMapping.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inode) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) error {
+ i.mapsMu.Lock()
+ mapped := i.mappings.AddMapping(ms, ar, offset, writable)
+ for _, r := range mapped {
+ i.pf.fileMapper.IncRefOn(r)
+ }
+ i.mapsMu.Unlock()
+ return nil
+}
+
+// RemoveMapping implements memmap.Mappable.RemoveMapping.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inode) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) {
+ i.mapsMu.Lock()
+ unmapped := i.mappings.RemoveMapping(ms, ar, offset, writable)
+ for _, r := range unmapped {
+ i.pf.fileMapper.DecRefOn(r)
+ }
+ i.mapsMu.Unlock()
+}
+
+// CopyMapping implements memmap.Mappable.CopyMapping.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inode) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR usermem.AddrRange, offset uint64, writable bool) error {
+ return i.AddMapping(ctx, ms, dstAR, offset, writable)
+}
+
+// Translate implements memmap.Mappable.Translate.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inode) Translate(ctx context.Context, required, optional memmap.MappableRange, at usermem.AccessType) ([]memmap.Translation, error) {
+ mr := optional
+ return []memmap.Translation{
+ {
+ Source: mr,
+ File: &i.pf,
+ Offset: mr.Start,
+ Perms: usermem.AnyAccess,
+ },
+ }, nil
+}
+
+// InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.
+//
+// Precondition: i.inode.canMap must be true.
+func (i *inode) InvalidateUnsavable(ctx context.Context) error {
+ // We expect the same host fd across save/restore, so all translations
+ // should be valid.
+ return nil
+}
diff --git a/pkg/usermem/addr.go b/pkg/usermem/addr.go
index e79210804..c4100481e 100644
--- a/pkg/usermem/addr.go
+++ b/pkg/usermem/addr.go
@@ -106,3 +106,20 @@ func (ar AddrRange) IsPageAligned() bool {
func (ar AddrRange) String() string {
return fmt.Sprintf("[%#x, %#x)", ar.Start, ar.End)
}
+
+// PageRoundDown/Up are equivalent to Addr.RoundDown/Up, but without the
+// potentially truncating conversion from uint64 to Addr. This is necessary
+// because there is no way to define generic "PageRoundDown/Up" functions in Go.
+
+// PageRoundDown returns x rounded down to the nearest page boundary.
+func PageRoundDown(x uint64) uint64 {
+ return x &^ (PageSize - 1)
+}
+
+// PageRoundUp returns x rounded up to the nearest page boundary.
+// ok is true iff rounding up did not wrap around.
+func PageRoundUp(x uint64) (addr uint64, ok bool) {
+ addr = PageRoundDown(x + PageSize - 1)
+ ok = addr >= x
+ return
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-02 16:32:14 +0000