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-rw-r--r--pkg/sentry/kernel/pipe/BUILD3
-rw-r--r--pkg/sentry/kernel/pipe/pipe.go6
-rw-r--r--pkg/sentry/kernel/pipe/pipe_unsafe.go35
-rw-r--r--pkg/sentry/kernel/pipe/pipe_util.go2
-rw-r--r--pkg/sentry/kernel/pipe/vfs.go232
5 files changed, 272 insertions, 6 deletions
diff --git a/pkg/sentry/kernel/pipe/BUILD b/pkg/sentry/kernel/pipe/BUILD
index f29dc0472..0db546b98 100644
--- a/pkg/sentry/kernel/pipe/BUILD
+++ b/pkg/sentry/kernel/pipe/BUILD
@@ -8,6 +8,7 @@ go_library(
"device.go",
"node.go",
"pipe.go",
+ "pipe_unsafe.go",
"pipe_util.go",
"reader.go",
"reader_writer.go",
@@ -20,11 +21,13 @@ go_library(
"//pkg/amutex",
"//pkg/buffer",
"//pkg/context",
+ "//pkg/safemem",
"//pkg/sentry/arch",
"//pkg/sentry/device",
"//pkg/sentry/fs",
"//pkg/sentry/fs/fsutil",
"//pkg/sentry/vfs",
+ "//pkg/sentry/vfs/lock",
"//pkg/sync",
"//pkg/syserror",
"//pkg/usermem",
diff --git a/pkg/sentry/kernel/pipe/pipe.go b/pkg/sentry/kernel/pipe/pipe.go
index 62c8691f1..79645d7d2 100644
--- a/pkg/sentry/kernel/pipe/pipe.go
+++ b/pkg/sentry/kernel/pipe/pipe.go
@@ -207,7 +207,10 @@ func (p *Pipe) read(ctx context.Context, ops readOps) (int64, error) {
p.mu.Lock()
defer p.mu.Unlock()
+ return p.readLocked(ctx, ops)
+}
+func (p *Pipe) readLocked(ctx context.Context, ops readOps) (int64, error) {
// Is the pipe empty?
if p.view.Size() == 0 {
if !p.HasWriters() {
@@ -246,7 +249,10 @@ type writeOps struct {
func (p *Pipe) write(ctx context.Context, ops writeOps) (int64, error) {
p.mu.Lock()
defer p.mu.Unlock()
+ return p.writeLocked(ctx, ops)
+}
+func (p *Pipe) writeLocked(ctx context.Context, ops writeOps) (int64, error) {
// Can't write to a pipe with no readers.
if !p.HasReaders() {
return 0, syscall.EPIPE
diff --git a/pkg/sentry/kernel/pipe/pipe_unsafe.go b/pkg/sentry/kernel/pipe/pipe_unsafe.go
new file mode 100644
index 000000000..dd60cba24
--- /dev/null
+++ b/pkg/sentry/kernel/pipe/pipe_unsafe.go
@@ -0,0 +1,35 @@
+// 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 pipe
+
+import (
+ "unsafe"
+)
+
+// lockTwoPipes locks both x.mu and y.mu in an order that is guaranteed to be
+// consistent for both lockTwoPipes(x, y) and lockTwoPipes(y, x), such that
+// concurrent calls cannot deadlock.
+//
+// Preconditions: x != y.
+func lockTwoPipes(x, y *Pipe) {
+ // Lock the two pipes in order of increasing address.
+ if uintptr(unsafe.Pointer(x)) < uintptr(unsafe.Pointer(y)) {
+ x.mu.Lock()
+ y.mu.Lock()
+ } else {
+ y.mu.Lock()
+ x.mu.Lock()
+ }
+}
diff --git a/pkg/sentry/kernel/pipe/pipe_util.go b/pkg/sentry/kernel/pipe/pipe_util.go
index 5a1d4fd57..aacf28da2 100644
--- a/pkg/sentry/kernel/pipe/pipe_util.go
+++ b/pkg/sentry/kernel/pipe/pipe_util.go
@@ -144,7 +144,7 @@ func (p *Pipe) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArgume
if v > math.MaxInt32 {
v = math.MaxInt32 // Silently truncate.
}
- // Copy result to user-space.
+ // Copy result to userspace.
_, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), int32(v), usermem.IOOpts{
AddressSpaceActive: true,
})
diff --git a/pkg/sentry/kernel/pipe/vfs.go b/pkg/sentry/kernel/pipe/vfs.go
index b54f08a30..c0e9ee1f4 100644
--- a/pkg/sentry/kernel/pipe/vfs.go
+++ b/pkg/sentry/kernel/pipe/vfs.go
@@ -16,9 +16,12 @@ package pipe
import (
"gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/buffer"
"gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/safemem"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/sentry/vfs/lock"
"gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/syserror"
"gvisor.dev/gvisor/pkg/usermem"
@@ -59,11 +62,13 @@ func NewVFSPipe(isNamed bool, sizeBytes, atomicIOBytes int64) *VFSPipe {
//
// Preconditions: statusFlags should not contain an open access mode.
func (vp *VFSPipe) ReaderWriterPair(mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32) (*vfs.FileDescription, *vfs.FileDescription) {
- return vp.newFD(mnt, vfsd, linux.O_RDONLY|statusFlags), vp.newFD(mnt, vfsd, linux.O_WRONLY|statusFlags)
+ // Connected pipes share the same locks.
+ locks := &lock.FileLocks{}
+ return vp.newFD(mnt, vfsd, linux.O_RDONLY|statusFlags, locks), vp.newFD(mnt, vfsd, linux.O_WRONLY|statusFlags, locks)
}
// Open opens the pipe represented by vp.
-func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32) (*vfs.FileDescription, error) {
+func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32, locks *lock.FileLocks) (*vfs.FileDescription, error) {
vp.mu.Lock()
defer vp.mu.Unlock()
@@ -73,7 +78,7 @@ func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, s
return nil, syserror.EINVAL
}
- fd := vp.newFD(mnt, vfsd, statusFlags)
+ fd := vp.newFD(mnt, vfsd, statusFlags, locks)
// Named pipes have special blocking semantics during open:
//
@@ -125,10 +130,11 @@ func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, s
}
// Preconditions: vp.mu must be held.
-func (vp *VFSPipe) newFD(mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32) *vfs.FileDescription {
+func (vp *VFSPipe) newFD(mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32, locks *lock.FileLocks) *vfs.FileDescription {
fd := &VFSPipeFD{
pipe: &vp.pipe,
}
+ fd.LockFD.Init(locks)
fd.vfsfd.Init(fd, statusFlags, mnt, vfsd, &vfs.FileDescriptionOptions{
DenyPRead: true,
DenyPWrite: true,
@@ -150,11 +156,14 @@ func (vp *VFSPipe) newFD(mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32) *
return &fd.vfsfd
}
-// VFSPipeFD implements vfs.FileDescriptionImpl for pipes.
+// VFSPipeFD implements vfs.FileDescriptionImpl for pipes. It also implements
+// non-atomic usermem.IO methods, allowing it to be passed as usermem.IO to
+// other FileDescriptions for splice(2) and tee(2).
type VFSPipeFD struct {
vfsfd vfs.FileDescription
vfs.FileDescriptionDefaultImpl
vfs.DentryMetadataFileDescriptionImpl
+ vfs.LockFD
pipe *Pipe
}
@@ -229,3 +238,216 @@ func (fd *VFSPipeFD) PipeSize() int64 {
func (fd *VFSPipeFD) SetPipeSize(size int64) (int64, error) {
return fd.pipe.SetFifoSize(size)
}
+
+// IOSequence returns a useremm.IOSequence that reads up to count bytes from,
+// or writes up to count bytes to, fd.
+func (fd *VFSPipeFD) IOSequence(count int64) usermem.IOSequence {
+ return usermem.IOSequence{
+ IO: fd,
+ Addrs: usermem.AddrRangeSeqOf(usermem.AddrRange{0, usermem.Addr(count)}),
+ }
+}
+
+// CopyIn implements usermem.IO.CopyIn.
+func (fd *VFSPipeFD) CopyIn(ctx context.Context, addr usermem.Addr, dst []byte, opts usermem.IOOpts) (int, error) {
+ origCount := int64(len(dst))
+ n, err := fd.pipe.read(ctx, readOps{
+ left: func() int64 {
+ return int64(len(dst))
+ },
+ limit: func(l int64) {
+ dst = dst[:l]
+ },
+ read: func(view *buffer.View) (int64, error) {
+ n, err := view.ReadAt(dst, 0)
+ view.TrimFront(int64(n))
+ return int64(n), err
+ },
+ })
+ if n > 0 {
+ fd.pipe.Notify(waiter.EventOut)
+ }
+ if err == nil && n != origCount {
+ return int(n), syserror.ErrWouldBlock
+ }
+ return int(n), err
+}
+
+// CopyOut implements usermem.IO.CopyOut.
+func (fd *VFSPipeFD) CopyOut(ctx context.Context, addr usermem.Addr, src []byte, opts usermem.IOOpts) (int, error) {
+ origCount := int64(len(src))
+ n, err := fd.pipe.write(ctx, writeOps{
+ left: func() int64 {
+ return int64(len(src))
+ },
+ limit: func(l int64) {
+ src = src[:l]
+ },
+ write: func(view *buffer.View) (int64, error) {
+ view.Append(src)
+ return int64(len(src)), nil
+ },
+ })
+ if n > 0 {
+ fd.pipe.Notify(waiter.EventIn)
+ }
+ if err == nil && n != origCount {
+ return int(n), syserror.ErrWouldBlock
+ }
+ return int(n), err
+}
+
+// ZeroOut implements usermem.IO.ZeroOut.
+func (fd *VFSPipeFD) ZeroOut(ctx context.Context, addr usermem.Addr, toZero int64, opts usermem.IOOpts) (int64, error) {
+ origCount := toZero
+ n, err := fd.pipe.write(ctx, writeOps{
+ left: func() int64 {
+ return toZero
+ },
+ limit: func(l int64) {
+ toZero = l
+ },
+ write: func(view *buffer.View) (int64, error) {
+ view.Grow(view.Size()+toZero, true /* zero */)
+ return toZero, nil
+ },
+ })
+ if n > 0 {
+ fd.pipe.Notify(waiter.EventIn)
+ }
+ if err == nil && n != origCount {
+ return n, syserror.ErrWouldBlock
+ }
+ return n, err
+}
+
+// CopyInTo implements usermem.IO.CopyInTo.
+func (fd *VFSPipeFD) CopyInTo(ctx context.Context, ars usermem.AddrRangeSeq, dst safemem.Writer, opts usermem.IOOpts) (int64, error) {
+ count := ars.NumBytes()
+ if count == 0 {
+ return 0, nil
+ }
+ origCount := count
+ n, err := fd.pipe.read(ctx, readOps{
+ left: func() int64 {
+ return count
+ },
+ limit: func(l int64) {
+ count = l
+ },
+ read: func(view *buffer.View) (int64, error) {
+ n, err := view.ReadToSafememWriter(dst, uint64(count))
+ view.TrimFront(int64(n))
+ return int64(n), err
+ },
+ })
+ if n > 0 {
+ fd.pipe.Notify(waiter.EventOut)
+ }
+ if err == nil && n != origCount {
+ return n, syserror.ErrWouldBlock
+ }
+ return n, err
+}
+
+// CopyOutFrom implements usermem.IO.CopyOutFrom.
+func (fd *VFSPipeFD) CopyOutFrom(ctx context.Context, ars usermem.AddrRangeSeq, src safemem.Reader, opts usermem.IOOpts) (int64, error) {
+ count := ars.NumBytes()
+ if count == 0 {
+ return 0, nil
+ }
+ origCount := count
+ n, err := fd.pipe.write(ctx, writeOps{
+ left: func() int64 {
+ return count
+ },
+ limit: func(l int64) {
+ count = l
+ },
+ write: func(view *buffer.View) (int64, error) {
+ n, err := view.WriteFromSafememReader(src, uint64(count))
+ return int64(n), err
+ },
+ })
+ if n > 0 {
+ fd.pipe.Notify(waiter.EventIn)
+ }
+ if err == nil && n != origCount {
+ return n, syserror.ErrWouldBlock
+ }
+ return n, err
+}
+
+// SwapUint32 implements usermem.IO.SwapUint32.
+func (fd *VFSPipeFD) SwapUint32(ctx context.Context, addr usermem.Addr, new uint32, opts usermem.IOOpts) (uint32, error) {
+ // How did a pipe get passed as the virtual address space to futex(2)?
+ panic("VFSPipeFD.SwapUint32 called unexpectedly")
+}
+
+// CompareAndSwapUint32 implements usermem.IO.CompareAndSwapUint32.
+func (fd *VFSPipeFD) CompareAndSwapUint32(ctx context.Context, addr usermem.Addr, old, new uint32, opts usermem.IOOpts) (uint32, error) {
+ panic("VFSPipeFD.CompareAndSwapUint32 called unexpectedly")
+}
+
+// LoadUint32 implements usermem.IO.LoadUint32.
+func (fd *VFSPipeFD) LoadUint32(ctx context.Context, addr usermem.Addr, opts usermem.IOOpts) (uint32, error) {
+ panic("VFSPipeFD.LoadUint32 called unexpectedly")
+}
+
+// Splice reads up to count bytes from src and writes them to dst. It returns
+// the number of bytes moved.
+//
+// Preconditions: count > 0.
+func Splice(ctx context.Context, dst, src *VFSPipeFD, count int64) (int64, error) {
+ return spliceOrTee(ctx, dst, src, count, true /* removeFromSrc */)
+}
+
+// Tee reads up to count bytes from src and writes them to dst, without
+// removing the read bytes from src. It returns the number of bytes copied.
+//
+// Preconditions: count > 0.
+func Tee(ctx context.Context, dst, src *VFSPipeFD, count int64) (int64, error) {
+ return spliceOrTee(ctx, dst, src, count, false /* removeFromSrc */)
+}
+
+// Preconditions: count > 0.
+func spliceOrTee(ctx context.Context, dst, src *VFSPipeFD, count int64, removeFromSrc bool) (int64, error) {
+ if dst.pipe == src.pipe {
+ return 0, syserror.EINVAL
+ }
+
+ lockTwoPipes(dst.pipe, src.pipe)
+ defer dst.pipe.mu.Unlock()
+ defer src.pipe.mu.Unlock()
+
+ n, err := dst.pipe.writeLocked(ctx, writeOps{
+ left: func() int64 {
+ return count
+ },
+ limit: func(l int64) {
+ count = l
+ },
+ write: func(dstView *buffer.View) (int64, error) {
+ return src.pipe.readLocked(ctx, readOps{
+ left: func() int64 {
+ return count
+ },
+ limit: func(l int64) {
+ count = l
+ },
+ read: func(srcView *buffer.View) (int64, error) {
+ n, err := srcView.ReadToSafememWriter(dstView, uint64(count))
+ if n > 0 && removeFromSrc {
+ srcView.TrimFront(int64(n))
+ }
+ return int64(n), err
+ },
+ })
+ },
+ })
+ if n > 0 {
+ dst.pipe.Notify(waiter.EventIn)
+ src.pipe.Notify(waiter.EventOut)
+ }
+ return n, err
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-01 12:43:39 +0000