1 files changed, 416 insertions, 0 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_aio.go b/pkg/sentry/syscalls/linux/sys_aio.go
new file mode 100644
index 000000000..1b27b2415
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/sys_aio.go
@@ -0,0 +1,416 @@
+// Copyright 2018 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 linux
+
+import (
+	"encoding/binary"
+
+	"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel/eventfd"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel/kdefs"
+	ktime "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/time"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/mm"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
+	"gvisor.googlesource.com/gvisor/pkg/syserror"
+)
+
+// I/O commands.
+const (
+	_IOCB_CMD_PREAD   = 0
+	_IOCB_CMD_PWRITE  = 1
+	_IOCB_CMD_FSYNC   = 2
+	_IOCB_CMD_FDSYNC  = 3
+	_IOCB_CMD_NOOP    = 6
+	_IOCB_CMD_PREADV  = 7
+	_IOCB_CMD_PWRITEV = 8
+)
+
+// I/O flags.
+const (
+	_IOCB_FLAG_RESFD = 1
+)
+
+// ioCallback describes an I/O request.
+//
+// The priority field is currently ignored in the implementation below. Also
+// note that the IOCB_FLAG_RESFD feature is not supported.
+type ioCallback struct {
+	Data      uint64
+	Key       uint32
+	Reserved1 uint32
+
+	OpCode  uint16
+	ReqPrio int16
+	FD      uint32
+
+	Buf    uint64
+	Bytes  uint64
+	Offset int64
+
+	Reserved2 uint64
+	Flags     uint32
+
+	// eventfd to signal if IOCB_FLAG_RESFD is set in flags.
+	ResFD uint32
+}
+
+// ioEvent describes an I/O result.
+//
+// +stateify savable
+type ioEvent struct {
+	Data    uint64
+	Obj     uint64
+	Result  int64
+	Result2 int64
+}
+
+// ioEventSize is the size of an ioEvent encoded.
+var ioEventSize = binary.Size(ioEvent{})
+
+// IoSetup implements linux syscall io_setup(2).
+func IoSetup(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	nrEvents := args[0].Int()
+	idAddr := args[1].Pointer()
+
+	// Linux uses the native long as the aio ID.
+	//
+	// The context pointer _must_ be zero initially.
+	var idIn uint64
+	if _, err := t.CopyIn(idAddr, &idIn); err != nil {
+		return 0, nil, err
+	}
+	if idIn != 0 {
+		return 0, nil, syserror.EINVAL
+	}
+
+	id, err := t.MemoryManager().NewAIOContext(t, uint32(nrEvents))
+	if err != nil {
+		return 0, nil, err
+	}
+
+	// Copy out the new ID.
+	if _, err := t.CopyOut(idAddr, &id); err != nil {
+		t.MemoryManager().DestroyAIOContext(t, id)
+		return 0, nil, err
+	}
+
+	return 0, nil, nil
+}
+
+// IoDestroy implements linux syscall io_destroy(2).
+func IoDestroy(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	id := args[0].Uint64()
+
+	// Destroy the given context.
+	if !t.MemoryManager().DestroyAIOContext(t, id) {
+		// Does not exist.
+		return 0, nil, syserror.EINVAL
+	}
+	// FIXME(fvoznika): Linux blocks until all AIO to the destroyed context is
+	// done.
+	return 0, nil, nil
+}
+
+// IoGetevents implements linux syscall io_getevents(2).
+func IoGetevents(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	id := args[0].Uint64()
+	minEvents := args[1].Int()
+	events := args[2].Int()
+	eventsAddr := args[3].Pointer()
+	timespecAddr := args[4].Pointer()
+
+	// Sanity check arguments.
+	if minEvents < 0 || minEvents > events {
+		return 0, nil, syserror.EINVAL
+	}
+
+	ctx, ok := t.MemoryManager().LookupAIOContext(t, id)
+	if !ok {
+		return 0, nil, syserror.EINVAL
+	}
+
+	// Setup the timeout.
+	var haveDeadline bool
+	var deadline ktime.Time
+	if timespecAddr != 0 {
+		d, err := copyTimespecIn(t, timespecAddr)
+		if err != nil {
+			return 0, nil, err
+		}
+		if !d.Valid() {
+			return 0, nil, syserror.EINVAL
+		}
+		deadline = t.Kernel().MonotonicClock().Now().Add(d.ToDuration())
+		haveDeadline = true
+	}
+
+	// Loop over all requests.
+	for count := int32(0); count < events; count++ {
+		// Get a request, per semantics.
+		var v interface{}
+		if count >= minEvents {
+			var ok bool
+			v, ok = ctx.PopRequest()
+			if !ok {
+				return uintptr(count), nil, nil
+			}
+		} else {
+			var err error
+			v, err = waitForRequest(ctx, t, haveDeadline, deadline)
+			if err != nil {
+				if count > 0 || err == syserror.ETIMEDOUT {
+					return uintptr(count), nil, nil
+				}
+				return 0, nil, syserror.ConvertIntr(err, syserror.EINTR)
+			}
+		}
+
+		ev := v.(*ioEvent)
+
+		// Copy out the result.
+		if _, err := t.CopyOut(eventsAddr, ev); err != nil {
+			if count > 0 {
+				return uintptr(count), nil, nil
+			}
+			// Nothing done.
+			return 0, nil, err
+		}
+
+		// Keep rolling.
+		eventsAddr += usermem.Addr(ioEventSize)
+	}
+
+	// Everything finished.
+	return uintptr(events), nil, nil
+}
+
+func waitForRequest(ctx *mm.AIOContext, t *kernel.Task, haveDeadline bool, deadline ktime.Time) (interface{}, error) {
+	for {
+		if v, ok := ctx.PopRequest(); ok {
+			// Request was readly available. Just return it.
+			return v, nil
+		}
+
+		// Need to wait for request completion.
+		done, active := ctx.WaitChannel()
+		if !active {
+			// Context has been destroyed.
+			return nil, syserror.EINVAL
+		}
+		if err := t.BlockWithDeadline(done, haveDeadline, deadline); err != nil {
+			return nil, err
+		}
+	}
+}
+
+// memoryFor returns appropriate memory for the given callback.
+func memoryFor(t *kernel.Task, cb *ioCallback) (usermem.IOSequence, error) {
+	bytes := int(cb.Bytes)
+	if bytes < 0 {
+		// Linux also requires that this field fit in ssize_t.
+		return usermem.IOSequence{}, syserror.EINVAL
+	}
+
+	// Since this I/O will be asynchronous with respect to t's task goroutine,
+	// we have no guarantee that t's AddressSpace will be active during the
+	// I/O.
+	switch cb.OpCode {
+	case _IOCB_CMD_PREAD, _IOCB_CMD_PWRITE:
+		return t.SingleIOSequence(usermem.Addr(cb.Buf), bytes, usermem.IOOpts{
+			AddressSpaceActive: false,
+		})
+
+	case _IOCB_CMD_PREADV, _IOCB_CMD_PWRITEV:
+		return t.IovecsIOSequence(usermem.Addr(cb.Buf), bytes, usermem.IOOpts{
+			AddressSpaceActive: false,
+		})
+
+	case _IOCB_CMD_FSYNC, _IOCB_CMD_FDSYNC, _IOCB_CMD_NOOP:
+		return usermem.IOSequence{}, nil
+
+	default:
+		// Not a supported command.
+		return usermem.IOSequence{}, syserror.EINVAL
+	}
+}
+
+func performCallback(t *kernel.Task, file *fs.File, cbAddr usermem.Addr, cb *ioCallback, ioseq usermem.IOSequence, ctx *mm.AIOContext, eventFile *fs.File) {
+	ev := &ioEvent{
+		Data: cb.Data,
+		Obj:  uint64(cbAddr),
+	}
+
+	// Construct a context.Context that will not be interrupted if t is
+	// interrupted.
+	c := t.AsyncContext()
+
+	var err error
+	switch cb.OpCode {
+	case _IOCB_CMD_PREAD, _IOCB_CMD_PREADV:
+		ev.Result, err = file.Preadv(c, ioseq, cb.Offset)
+	case _IOCB_CMD_PWRITE, _IOCB_CMD_PWRITEV:
+		ev.Result, err = file.Pwritev(c, ioseq, cb.Offset)
+	case _IOCB_CMD_FSYNC:
+		err = file.Fsync(c, 0, fs.FileMaxOffset, fs.SyncAll)
+	case _IOCB_CMD_FDSYNC:
+		err = file.Fsync(c, 0, fs.FileMaxOffset, fs.SyncData)
+	}
+
+	// Update the result.
+	if err != nil {
+		err = handleIOError(t, ev.Result != 0 /* partial */, err, nil /* never interrupted */, "aio", file)
+		ev.Result = -int64(t.ExtractErrno(err, 0))
+	}
+
+	file.DecRef()
+
+	// Queue the result for delivery.
+	ctx.FinishRequest(ev)
+
+	// Notify the event file if one was specified. This needs to happen
+	// *after* queueing the result to avoid racing with the thread we may
+	// wake up.
+	if eventFile != nil {
+		eventFile.FileOperations.(*eventfd.EventOperations).Signal(1)
+		eventFile.DecRef()
+	}
+}
+
+// submitCallback processes a single callback.
+func submitCallback(t *kernel.Task, id uint64, cb *ioCallback, cbAddr usermem.Addr) error {
+	file := t.FDMap().GetFile(kdefs.FD(cb.FD))
+	if file == nil {
+		// File not found.
+		return syserror.EBADF
+	}
+	defer file.DecRef()
+
+	// Was there an eventFD? Extract it.
+	var eventFile *fs.File
+	if cb.Flags&_IOCB_FLAG_RESFD != 0 {
+		eventFile = t.FDMap().GetFile(kdefs.FD(cb.ResFD))
+		if eventFile == nil {
+			// Bad FD.
+			return syserror.EBADF
+		}
+		defer eventFile.DecRef()
+
+		// Check that it is an eventfd.
+		if _, ok := eventFile.FileOperations.(*eventfd.EventOperations); !ok {
+			// Not an event FD.
+			return syserror.EINVAL
+		}
+	}
+
+	ioseq, err := memoryFor(t, cb)
+	if err != nil {
+		return err
+	}
+
+	// Check offset for reads/writes.
+	switch cb.OpCode {
+	case _IOCB_CMD_PREAD, _IOCB_CMD_PREADV, _IOCB_CMD_PWRITE, _IOCB_CMD_PWRITEV:
+		if cb.Offset < 0 {
+			return syserror.EINVAL
+		}
+	}
+
+	// Prepare the request.
+	ctx, ok := t.MemoryManager().LookupAIOContext(t, id)
+	if !ok {
+		return syserror.EINVAL
+	}
+	if ready := ctx.Prepare(); !ready {
+		// Context is busy.
+		return syserror.EAGAIN
+	}
+
+	if eventFile != nil {
+		// The request is set. Make sure there's a ref on the file.
+		//
+		// This is necessary when the callback executes on completion,
+		// which is also what will release this reference.
+		eventFile.IncRef()
+	}
+
+	// Perform the request asynchronously.
+	file.IncRef()
+	fs.Async(func() { performCallback(t, file, cbAddr, cb, ioseq, ctx, eventFile) })
+
+	// All set.
+	return nil
+}
+
+// IoSubmit implements linux syscall io_submit(2).
+func IoSubmit(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	id := args[0].Uint64()
+	nrEvents := args[1].Int()
+	addr := args[2].Pointer()
+
+	if nrEvents < 0 {
+		return 0, nil, syserror.EINVAL
+	}
+
+	for i := int32(0); i < nrEvents; i++ {
+		// Copy in the address.
+		cbAddrNative := t.Arch().Native(0)
+		if _, err := t.CopyIn(addr, cbAddrNative); err != nil {
+			if i > 0 {
+				// Some successful.
+				return uintptr(i), nil, nil
+			}
+			// Nothing done.
+			return 0, nil, err
+		}
+
+		// Copy in this callback.
+		var cb ioCallback
+		cbAddr := usermem.Addr(t.Arch().Value(cbAddrNative))
+		if _, err := t.CopyIn(cbAddr, &cb); err != nil {
+
+			if i > 0 {
+				// Some have been successful.
+				return uintptr(i), nil, nil
+			}
+			// Nothing done.
+			return 0, nil, err
+		}
+
+		// Process this callback.
+		if err := submitCallback(t, id, &cb, cbAddr); err != nil {
+			if i > 0 {
+				// Partial success.
+				return uintptr(i), nil, nil
+			}
+			// Nothing done.
+			return 0, nil, err
+		}
+
+		// Advance to the next one.
+		addr += usermem.Addr(t.Arch().Width())
+	}
+
+	return uintptr(nrEvents), nil, nil
+}
+
+// IoCancel implements linux syscall io_cancel(2).
+//
+// It is not presently supported (ENOSYS indicates no support on this
+// architecture).
+func IoCancel(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	return 0, nil, syserror.ENOSYS
+}