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Diffstat (limited to 'pkg/sentry/kernel/pipe/vfs.go')
-rw-r--r--pkg/sentry/kernel/pipe/vfs.go173
1 files changed, 92 insertions, 81 deletions
diff --git a/pkg/sentry/kernel/pipe/vfs.go b/pkg/sentry/kernel/pipe/vfs.go
index 6416e0dd8..b54f08a30 100644
--- a/pkg/sentry/kernel/pipe/vfs.go
+++ b/pkg/sentry/kernel/pipe/vfs.go
@@ -15,14 +15,13 @@
package pipe
import (
- "sync"
-
"gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/sentry/arch"
- "gvisor.dev/gvisor/pkg/sentry/context"
- "gvisor.dev/gvisor/pkg/sentry/usermem"
"gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
"gvisor.dev/gvisor/pkg/waiter"
)
@@ -50,38 +49,42 @@ type VFSPipe struct {
}
// NewVFSPipe returns an initialized VFSPipe.
-func NewVFSPipe(sizeBytes, atomicIOBytes int64) *VFSPipe {
+func NewVFSPipe(isNamed bool, sizeBytes, atomicIOBytes int64) *VFSPipe {
var vp VFSPipe
- initPipe(&vp.pipe, true /* isNamed */, sizeBytes, atomicIOBytes)
+ initPipe(&vp.pipe, isNamed, sizeBytes, atomicIOBytes)
return &vp
}
-// NewVFSPipeFD opens a named pipe. Named pipes have special blocking semantics
-// during open:
+// ReaderWriterPair returns read-only and write-only FDs for vp.
//
-// "Normally, opening the FIFO blocks until the other end is opened also. A
-// process can open a FIFO in nonblocking mode. In this case, opening for
-// read-only will succeed even if no-one has opened on the write side yet,
-// opening for write-only will fail with ENXIO (no such device or address)
-// unless the other end has already been opened. Under Linux, opening a FIFO
-// for read and write will succeed both in blocking and nonblocking mode. POSIX
-// leaves this behavior undefined. This can be used to open a FIFO for writing
-// while there are no readers available." - fifo(7)
-func (vp *VFSPipe) NewVFSPipeFD(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, vfsfd *vfs.FileDescription, flags uint32) (*VFSPipeFD, error) {
+// 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)
+}
+
+// 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) {
vp.mu.Lock()
defer vp.mu.Unlock()
- readable := vfs.MayReadFileWithOpenFlags(flags)
- writable := vfs.MayWriteFileWithOpenFlags(flags)
+ readable := vfs.MayReadFileWithOpenFlags(statusFlags)
+ writable := vfs.MayWriteFileWithOpenFlags(statusFlags)
if !readable && !writable {
return nil, syserror.EINVAL
}
- vfd, err := vp.open(rp, vfsd, vfsfd, flags)
- if err != nil {
- return nil, err
- }
+ fd := vp.newFD(mnt, vfsd, statusFlags)
+ // Named pipes have special blocking semantics during open:
+ //
+ // "Normally, opening the FIFO blocks until the other end is opened also. A
+ // process can open a FIFO in nonblocking mode. In this case, opening for
+ // read-only will succeed even if no-one has opened on the write side yet,
+ // opening for write-only will fail with ENXIO (no such device or address)
+ // unless the other end has already been opened. Under Linux, opening a
+ // FIFO for read and write will succeed both in blocking and nonblocking
+ // mode. POSIX leaves this behavior undefined. This can be used to open a
+ // FIFO for writing while there are no readers available." - fifo(7)
switch {
case readable && writable:
// Pipes opened for read-write always succeed without blocking.
@@ -90,23 +93,26 @@ func (vp *VFSPipe) NewVFSPipeFD(ctx context.Context, rp *vfs.ResolvingPath, vfsd
case readable:
newHandleLocked(&vp.rWakeup)
- // If this pipe is being opened as nonblocking and there's no
+ // If this pipe is being opened as blocking and there's no
// writer, we have to wait for a writer to open the other end.
- if flags&linux.O_NONBLOCK == 0 && !vp.pipe.HasWriters() && !waitFor(&vp.mu, &vp.wWakeup, ctx) {
+ if vp.pipe.isNamed && statusFlags&linux.O_NONBLOCK == 0 && !vp.pipe.HasWriters() && !waitFor(&vp.mu, &vp.wWakeup, ctx) {
+ fd.DecRef()
return nil, syserror.EINTR
}
case writable:
newHandleLocked(&vp.wWakeup)
- if !vp.pipe.HasReaders() {
- // Nonblocking, write-only opens fail with ENXIO when
- // the read side isn't open yet.
- if flags&linux.O_NONBLOCK != 0 {
+ if vp.pipe.isNamed && !vp.pipe.HasReaders() {
+ // Non-blocking, write-only opens fail with ENXIO when the read
+ // side isn't open yet.
+ if statusFlags&linux.O_NONBLOCK != 0 {
+ fd.DecRef()
return nil, syserror.ENXIO
}
// Wait for a reader to open the other end.
if !waitFor(&vp.mu, &vp.rWakeup, ctx) {
+ fd.DecRef()
return nil, syserror.EINTR
}
}
@@ -115,102 +121,93 @@ func (vp *VFSPipe) NewVFSPipeFD(ctx context.Context, rp *vfs.ResolvingPath, vfsd
panic("invalid pipe flags: must be readable, writable, or both")
}
- return vfd, nil
+ return fd, nil
}
// Preconditions: vp.mu must be held.
-func (vp *VFSPipe) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, vfsfd *vfs.FileDescription, flags uint32) (*VFSPipeFD, error) {
- var fd VFSPipeFD
- fd.flags = flags
- fd.readable = vfs.MayReadFileWithOpenFlags(flags)
- fd.writable = vfs.MayWriteFileWithOpenFlags(flags)
- fd.vfsfd = vfsfd
- fd.pipe = &vp.pipe
- if fd.writable {
- // The corresponding Mount.EndWrite() is in VFSPipe.Release().
- if err := rp.Mount().CheckBeginWrite(); err != nil {
- return nil, err
- }
+func (vp *VFSPipe) newFD(mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32) *vfs.FileDescription {
+ fd := &VFSPipeFD{
+ pipe: &vp.pipe,
}
+ fd.vfsfd.Init(fd, statusFlags, mnt, vfsd, &vfs.FileDescriptionOptions{
+ DenyPRead: true,
+ DenyPWrite: true,
+ UseDentryMetadata: true,
+ })
switch {
- case fd.readable && fd.writable:
+ case fd.vfsfd.IsReadable() && fd.vfsfd.IsWritable():
vp.pipe.rOpen()
vp.pipe.wOpen()
- case fd.readable:
+ case fd.vfsfd.IsReadable():
vp.pipe.rOpen()
- case fd.writable:
+ case fd.vfsfd.IsWritable():
vp.pipe.wOpen()
default:
panic("invalid pipe flags: must be readable, writable, or both")
}
- return &fd, nil
+ return &fd.vfsfd
}
-// VFSPipeFD implements a subset of vfs.FileDescriptionImpl for pipes. It is
-// expected that filesystesm will use this in a struct implementing
-// vfs.FileDescriptionImpl.
+// VFSPipeFD implements vfs.FileDescriptionImpl for pipes.
type VFSPipeFD struct {
- pipe *Pipe
- flags uint32
- readable bool
- writable bool
- vfsfd *vfs.FileDescription
+ vfsfd vfs.FileDescription
+ vfs.FileDescriptionDefaultImpl
+ vfs.DentryMetadataFileDescriptionImpl
+
+ pipe *Pipe
}
// Release implements vfs.FileDescriptionImpl.Release.
func (fd *VFSPipeFD) Release() {
var event waiter.EventMask
- if fd.readable {
+ if fd.vfsfd.IsReadable() {
fd.pipe.rClose()
- event |= waiter.EventIn
+ event |= waiter.EventOut
}
- if fd.writable {
+ if fd.vfsfd.IsWritable() {
fd.pipe.wClose()
- event |= waiter.EventOut
+ event |= waiter.EventIn | waiter.EventHUp
}
if event == 0 {
panic("invalid pipe flags: must be readable, writable, or both")
}
- if fd.writable {
- fd.vfsfd.VirtualDentry().Mount().EndWrite()
- }
-
fd.pipe.Notify(event)
}
-// OnClose implements vfs.FileDescriptionImpl.OnClose.
-func (fd *VFSPipeFD) OnClose(_ context.Context) error {
- return nil
+// Readiness implements waiter.Waitable.Readiness.
+func (fd *VFSPipeFD) Readiness(mask waiter.EventMask) waiter.EventMask {
+ switch {
+ case fd.vfsfd.IsReadable() && fd.vfsfd.IsWritable():
+ return fd.pipe.rwReadiness()
+ case fd.vfsfd.IsReadable():
+ return fd.pipe.rReadiness()
+ case fd.vfsfd.IsWritable():
+ return fd.pipe.wReadiness()
+ default:
+ panic("pipe FD is neither readable nor writable")
+ }
+}
+
+// EventRegister implements waiter.Waitable.EventRegister.
+func (fd *VFSPipeFD) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
+ fd.pipe.EventRegister(e, mask)
}
-// PRead implements vfs.FileDescriptionImpl.PRead.
-func (fd *VFSPipeFD) PRead(_ context.Context, _ usermem.IOSequence, _ int64, _ vfs.ReadOptions) (int64, error) {
- return 0, syserror.ESPIPE
+// EventUnregister implements waiter.Waitable.EventUnregister.
+func (fd *VFSPipeFD) EventUnregister(e *waiter.Entry) {
+ fd.pipe.EventUnregister(e)
}
// Read implements vfs.FileDescriptionImpl.Read.
func (fd *VFSPipeFD) Read(ctx context.Context, dst usermem.IOSequence, _ vfs.ReadOptions) (int64, error) {
- if !fd.readable {
- return 0, syserror.EINVAL
- }
-
return fd.pipe.Read(ctx, dst)
}
-// PWrite implements vfs.FileDescriptionImpl.PWrite.
-func (fd *VFSPipeFD) PWrite(_ context.Context, _ usermem.IOSequence, _ int64, _ vfs.WriteOptions) (int64, error) {
- return 0, syserror.ESPIPE
-}
-
// Write implements vfs.FileDescriptionImpl.Write.
func (fd *VFSPipeFD) Write(ctx context.Context, src usermem.IOSequence, _ vfs.WriteOptions) (int64, error) {
- if !fd.writable {
- return 0, syserror.EINVAL
- }
-
return fd.pipe.Write(ctx, src)
}
@@ -218,3 +215,17 @@ func (fd *VFSPipeFD) Write(ctx context.Context, src usermem.IOSequence, _ vfs.Wr
func (fd *VFSPipeFD) Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) {
return fd.pipe.Ioctl(ctx, uio, args)
}
+
+// PipeSize implements fcntl(F_GETPIPE_SZ).
+func (fd *VFSPipeFD) PipeSize() int64 {
+ // Inline Pipe.FifoSize() rather than calling it with nil Context and
+ // fs.File and ignoring the returned error (which is always nil).
+ fd.pipe.mu.Lock()
+ defer fd.pipe.mu.Unlock()
+ return fd.pipe.max
+}
+
+// SetPipeSize implements fcntl(F_SETPIPE_SZ).
+func (fd *VFSPipeFD) SetPipeSize(size int64) (int64, error) {
+ return fd.pipe.SetFifoSize(size)
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-23 07:34:00 +0000