Rename marshal.Task to marshal.CopyContext.

CopyContext is a better name for the interface because from
go-marshal's perspective, the interface has nothing to do with a
task. A kernel.Task happens to implement the interface, but so can
other things like MemoryManager and IO sequences.

PiperOrigin-RevId: 331959678

7 files changed, 74 insertions, 72 deletions

diff --git a/pkg/abi/linux/netfilter.go b/pkg/abi/linux/netfilter.go
index 6ef91b402..1c5b34711 100644
--- a/pkg/abi/linux/netfilter.go
+++ b/pkg/abi/linux/netfilter.go
@@ -450,9 +450,9 @@ func (ke *KernelIPTGetEntries) UnmarshalUnsafe(src []byte) {
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
-func (ke *KernelIPTGetEntries) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-	buf := task.CopyScratchBuffer(ke.SizeBytes()) // escapes: okay.
-	length, err := task.CopyInBytes(addr, buf)    // escapes: okay.
+func (ke *KernelIPTGetEntries) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+	buf := cc.CopyScratchBuffer(ke.SizeBytes()) // escapes: okay.
+	length, err := cc.CopyInBytes(addr, buf)    // escapes: okay.
 	// Unmarshal unconditionally. If we had a short copy-in, this results in a
 	// partially unmarshalled struct.
 	ke.UnmarshalBytes(buf) // escapes: fallback.
@@ -460,21 +460,21 @@ func (ke *KernelIPTGetEntries) CopyIn(task marshal.Task, addr usermem.Addr) (int
 }
 
 // CopyOut implements marshal.Marshallable.CopyOut.
-func (ke *KernelIPTGetEntries) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
+func (ke *KernelIPTGetEntries) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
 	// Type KernelIPTGetEntries doesn't have a packed layout in memory, fall
 	// back to MarshalBytes.
-	return task.CopyOutBytes(addr, ke.marshalAll(task))
+	return cc.CopyOutBytes(addr, ke.marshalAll(cc))
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
-func (ke *KernelIPTGetEntries) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
+func (ke *KernelIPTGetEntries) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
 	// Type KernelIPTGetEntries doesn't have a packed layout in memory, fall
 	// back to MarshalBytes.
-	return task.CopyOutBytes(addr, ke.marshalAll(task)[:limit])
+	return cc.CopyOutBytes(addr, ke.marshalAll(cc)[:limit])
 }
 
-func (ke *KernelIPTGetEntries) marshalAll(task marshal.Task) []byte {
-	buf := task.CopyScratchBuffer(ke.SizeBytes())
+func (ke *KernelIPTGetEntries) marshalAll(cc marshal.CopyContext) []byte {
+	buf := cc.CopyScratchBuffer(ke.SizeBytes())
 	ke.MarshalBytes(buf)
 	return buf
 }
diff --git a/pkg/abi/linux/netfilter_ipv6.go b/pkg/abi/linux/netfilter_ipv6.go
index 347c8c591..a137940b6 100644
--- a/pkg/abi/linux/netfilter_ipv6.go
+++ b/pkg/abi/linux/netfilter_ipv6.go
@@ -128,9 +128,9 @@ func (ke *KernelIP6TGetEntries) UnmarshalUnsafe(src []byte) {
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
-func (ke *KernelIP6TGetEntries) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-	buf := task.CopyScratchBuffer(ke.SizeBytes()) // escapes: okay.
-	length, err := task.CopyInBytes(addr, buf)    // escapes: okay.
+func (ke *KernelIP6TGetEntries) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+	buf := cc.CopyScratchBuffer(ke.SizeBytes()) // escapes: okay.
+	length, err := cc.CopyInBytes(addr, buf)    // escapes: okay.
 	// Unmarshal unconditionally. If we had a short copy-in, this results
 	// in a partially unmarshalled struct.
 	ke.UnmarshalBytes(buf) // escapes: fallback.
@@ -138,21 +138,21 @@ func (ke *KernelIP6TGetEntries) CopyIn(task marshal.Task, addr usermem.Addr) (in
 }
 
 // CopyOut implements marshal.Marshallable.CopyOut.
-func (ke *KernelIP6TGetEntries) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
+func (ke *KernelIP6TGetEntries) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
 	// Type KernelIP6TGetEntries doesn't have a packed layout in memory,
 	// fall back to MarshalBytes.
-	return task.CopyOutBytes(addr, ke.marshalAll(task))
+	return cc.CopyOutBytes(addr, ke.marshalAll(cc))
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
-func (ke *KernelIP6TGetEntries) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
+func (ke *KernelIP6TGetEntries) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
 	// Type KernelIP6TGetEntries doesn't have a packed layout in memory, fall
 	// back to MarshalBytes.
-	return task.CopyOutBytes(addr, ke.marshalAll(task)[:limit])
+	return cc.CopyOutBytes(addr, ke.marshalAll(cc)[:limit])
 }
 
-func (ke *KernelIP6TGetEntries) marshalAll(task marshal.Task) []byte {
-	buf := task.CopyScratchBuffer(ke.SizeBytes())
+func (ke *KernelIP6TGetEntries) marshalAll(cc marshal.CopyContext) []byte {
+	buf := cc.CopyScratchBuffer(ke.SizeBytes())
 	ke.MarshalBytes(buf)
 	return buf
 }
diff --git a/pkg/marshal/marshal.go b/pkg/marshal/marshal.go
index 85b196f08..d8cb44b40 100644
--- a/pkg/marshal/marshal.go
+++ b/pkg/marshal/marshal.go
@@ -26,9 +26,10 @@ import (
 	"gvisor.dev/gvisor/pkg/usermem"
 )
 
-// Task provides a subset of kernel.Task, used in marshalling. We don't import
-// the kernel package directly to avoid circular dependency.
-type Task interface {
+// CopyContext defines the memory operations required to marshal to and from
+// user memory. Typically, kernel.Task is used to provide implementations for
+// these operations.
+type CopyContext interface {
 	// CopyScratchBuffer provides a task goroutine-local scratch buffer. See
 	// kernel.CopyScratchBuffer.
 	CopyScratchBuffer(size int) []byte
@@ -107,7 +108,7 @@ type Marshallable interface {
 	// If the copy-in from the task memory is only partially successful, CopyIn
 	// should still attempt to deserialize as much data as possible. See comment
 	// for UnmarshalBytes.
-	CopyIn(task Task, addr usermem.Addr) (int, error)
+	CopyIn(cc CopyContext, addr usermem.Addr) (int, error)
 
 	// CopyOut serializes a Marshallable type to a task's memory. This may only
 	// be called from a task goroutine. This is more efficient than calling
@@ -118,7 +119,7 @@ type Marshallable interface {
 	// The copy-out to the task memory may be partially successful, in which
 	// case CopyOut returns how much data was serialized. See comment for
 	// MarshalBytes for implications.
-	CopyOut(task Task, addr usermem.Addr) (int, error)
+	CopyOut(cc CopyContext, addr usermem.Addr) (int, error)
 
 	// CopyOutN is like CopyOut, but explicitly requests a partial
 	// copy-out. Note that this may yield unexpected results for non-packed
@@ -126,7 +127,7 @@ type Marshallable interface {
 	// comment on MarshalBytes.
 	//
 	// The limit must be less than or equal to SizeBytes().
-	CopyOutN(task Task, addr usermem.Addr, limit int) (int, error)
+	CopyOutN(cc CopyContext, addr usermem.Addr, limit int) (int, error)
 }
 
 // go-marshal generates additional functions for a type based on additional
@@ -156,10 +157,10 @@ type Marshallable interface {
 // func UnmarshalUnsafeFooSlice(dst []Foo, src []byte) (int, error) { ... }
 //
 // // CopyFooSliceIn copies in a slice of Foo objects from the task's memory.
-// func CopyFooSliceIn(task marshal.Task, addr usermem.Addr, dst []Foo) (int, error) { ... }
+// func CopyFooSliceIn(cc marshal.CopyContext, addr usermem.Addr, dst []Foo) (int, error) { ... }
 //
 // // CopyFooSliceIn copies out a slice of Foo objects to the task's memory.
-// func CopyFooSliceOut(task marshal.Task, addr usermem.Addr, src []Foo) (int, error) { ... }
+// func CopyFooSliceOut(cc marshal.CopyContext, addr usermem.Addr, src []Foo) (int, error) { ... }
 //
 // The name of the functions are of the format "Copy%sIn" and "Copy%sOut", where
 // %s is the first argument to the slice clause. This directive is not supported
@@ -174,10 +175,10 @@ type Marshallable interface {
 // This is only valid on newtypes on primitives, and causes the generated
 // functions to accept slices of the inner type instead:
 //
-// func CopyInt32SliceIn(task marshal.Task, addr usermem.Addr, dst []int32) (int, error) { ... }
+// func CopyInt32SliceIn(cc marshal.CopyContext, addr usermem.Addr, dst []int32) (int, error) { ... }
 //
 // Without "inner", they would instead be:
 //
-// func CopyInt32SliceIn(task marshal.Task, addr usermem.Addr, dst []Int32) (int, error) { ... }
+// func CopyInt32SliceIn(cc marshal.CopyContext, addr usermem.Addr, dst []Int32) (int, error) { ... }
 //
 // This may help avoid a cast depending on how the generated functions are used.
diff --git a/pkg/marshal/marshal_impl_util.go b/pkg/marshal/marshal_impl_util.go
index 89c7d3575..69f33321e 100644
--- a/pkg/marshal/marshal_impl_util.go
+++ b/pkg/marshal/marshal_impl_util.go
@@ -63,16 +63,16 @@ func (StubMarshallable) UnmarshalUnsafe(src []byte) {
 }
 
 // CopyIn implements Marshallable.CopyIn.
-func (StubMarshallable) CopyIn(task Task, addr usermem.Addr) (int, error) {
+func (StubMarshallable) CopyIn(cc CopyContext, addr usermem.Addr) (int, error) {
 	panic("Please implement your own CopyIn function")
 }
 
 // CopyOut implements Marshallable.CopyOut.
-func (StubMarshallable) CopyOut(task Task, addr usermem.Addr) (int, error) {
+func (StubMarshallable) CopyOut(cc CopyContext, addr usermem.Addr) (int, error) {
 	panic("Please implement your own CopyOut function")
 }
 
 // CopyOutN implements Marshallable.CopyOutN.
-func (StubMarshallable) CopyOutN(task Task, addr usermem.Addr, limit int) (int, error) {
+func (StubMarshallable) CopyOutN(cc CopyContext, addr usermem.Addr, limit int) (int, error) {
 	panic("Please implement your own CopyOutN function")
 }
diff --git a/pkg/marshal/primitive/primitive.go b/pkg/marshal/primitive/primitive.go
index 140a9b78c..dfdae5d60 100644
--- a/pkg/marshal/primitive/primitive.go
+++ b/pkg/marshal/primitive/primitive.go
@@ -101,18 +101,18 @@ func (b *ByteSlice) UnmarshalUnsafe(src []byte) {
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
-func (b *ByteSlice) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
-	return task.CopyInBytes(addr, *b)
+func (b *ByteSlice) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+	return cc.CopyInBytes(addr, *b)
 }
 
 // CopyOut implements marshal.Marshallable.CopyOut.
-func (b *ByteSlice) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
-	return task.CopyOutBytes(addr, *b)
+func (b *ByteSlice) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
+	return cc.CopyOutBytes(addr, *b)
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
-func (b *ByteSlice) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
-	return task.CopyOutBytes(addr, (*b)[:limit])
+func (b *ByteSlice) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
+	return cc.CopyOutBytes(addr, (*b)[:limit])
 }
 
 // WriteTo implements io.WriterTo.WriteTo.
@@ -130,9 +130,9 @@ var _ marshal.Marshallable = (*ByteSlice)(nil)
 
 // CopyInt16In is a convenient wrapper for copying in an int16 from the task's
 // memory.
-func CopyInt16In(task marshal.Task, addr usermem.Addr, dst *int16) (int, error) {
+func CopyInt16In(cc marshal.CopyContext, addr usermem.Addr, dst *int16) (int, error) {
 	var buf Int16
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -142,16 +142,16 @@ func CopyInt16In(task marshal.Task, addr usermem.Addr, dst *int16) (int, error)
 
 // CopyInt16Out is a convenient wrapper for copying out an int16 to the task's
 // memory.
-func CopyInt16Out(task marshal.Task, addr usermem.Addr, src int16) (int, error) {
+func CopyInt16Out(cc marshal.CopyContext, addr usermem.Addr, src int16) (int, error) {
 	srcP := Int16(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
 
 // CopyUint16In is a convenient wrapper for copying in a uint16 from the task's
 // memory.
-func CopyUint16In(task marshal.Task, addr usermem.Addr, dst *uint16) (int, error) {
+func CopyUint16In(cc marshal.CopyContext, addr usermem.Addr, dst *uint16) (int, error) {
 	var buf Uint16
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -161,18 +161,18 @@ func CopyUint16In(task marshal.Task, addr usermem.Addr, dst *uint16) (int, error
 
 // CopyUint16Out is a convenient wrapper for copying out a uint16 to the task's
 // memory.
-func CopyUint16Out(task marshal.Task, addr usermem.Addr, src uint16) (int, error) {
+func CopyUint16Out(cc marshal.CopyContext, addr usermem.Addr, src uint16) (int, error) {
 	srcP := Uint16(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
 
 // 32-bit integers
 
 // CopyInt32In is a convenient wrapper for copying in an int32 from the task's
 // memory.
-func CopyInt32In(task marshal.Task, addr usermem.Addr, dst *int32) (int, error) {
+func CopyInt32In(cc marshal.CopyContext, addr usermem.Addr, dst *int32) (int, error) {
 	var buf Int32
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -182,16 +182,16 @@ func CopyInt32In(task marshal.Task, addr usermem.Addr, dst *int32) (int, error)
 
 // CopyInt32Out is a convenient wrapper for copying out an int32 to the task's
 // memory.
-func CopyInt32Out(task marshal.Task, addr usermem.Addr, src int32) (int, error) {
+func CopyInt32Out(cc marshal.CopyContext, addr usermem.Addr, src int32) (int, error) {
 	srcP := Int32(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
 
 // CopyUint32In is a convenient wrapper for copying in a uint32 from the task's
 // memory.
-func CopyUint32In(task marshal.Task, addr usermem.Addr, dst *uint32) (int, error) {
+func CopyUint32In(cc marshal.CopyContext, addr usermem.Addr, dst *uint32) (int, error) {
 	var buf Uint32
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -201,18 +201,18 @@ func CopyUint32In(task marshal.Task, addr usermem.Addr, dst *uint32) (int, error
 
 // CopyUint32Out is a convenient wrapper for copying out a uint32 to the task's
 // memory.
-func CopyUint32Out(task marshal.Task, addr usermem.Addr, src uint32) (int, error) {
+func CopyUint32Out(cc marshal.CopyContext, addr usermem.Addr, src uint32) (int, error) {
 	srcP := Uint32(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
 
 // 64-bit integers
 
 // CopyInt64In is a convenient wrapper for copying in an int64 from the task's
 // memory.
-func CopyInt64In(task marshal.Task, addr usermem.Addr, dst *int64) (int, error) {
+func CopyInt64In(cc marshal.CopyContext, addr usermem.Addr, dst *int64) (int, error) {
 	var buf Int64
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -222,16 +222,16 @@ func CopyInt64In(task marshal.Task, addr usermem.Addr, dst *int64) (int, error)
 
 // CopyInt64Out is a convenient wrapper for copying out an int64 to the task's
 // memory.
-func CopyInt64Out(task marshal.Task, addr usermem.Addr, src int64) (int, error) {
+func CopyInt64Out(cc marshal.CopyContext, addr usermem.Addr, src int64) (int, error) {
 	srcP := Int64(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
 
 // CopyUint64In is a convenient wrapper for copying in a uint64 from the task's
 // memory.
-func CopyUint64In(task marshal.Task, addr usermem.Addr, dst *uint64) (int, error) {
+func CopyUint64In(cc marshal.CopyContext, addr usermem.Addr, dst *uint64) (int, error) {
 	var buf Uint64
-	n, err := buf.CopyIn(task, addr)
+	n, err := buf.CopyIn(cc, addr)
 	if err != nil {
 		return n, err
 	}
@@ -241,7 +241,7 @@ func CopyUint64In(task marshal.Task, addr usermem.Addr, dst *uint64) (int, error
 
 // CopyUint64Out is a convenient wrapper for copying out a uint64 to the task's
 // memory.
-func CopyUint64Out(task marshal.Task, addr usermem.Addr, src uint64) (int, error) {
+func CopyUint64Out(cc marshal.CopyContext, addr usermem.Addr, src uint64) (int, error) {
 	srcP := Uint64(src)
-	return srcP.CopyOut(task, addr)
+	return srcP.CopyOut(cc, addr)
 }
diff --git a/pkg/sentry/fsimpl/fuse/dev_test.go b/pkg/sentry/fsimpl/fuse/dev_test.go
index 6baf56520..c18921dd8 100644
--- a/pkg/sentry/fsimpl/fuse/dev_test.go
+++ b/pkg/sentry/fsimpl/fuse/dev_test.go
@@ -408,17 +408,17 @@ func (t *testPayload) UnmarshalUnsafe(src []byte) {
 }
 
 // CopyOutN implements marshal.Marshallable.CopyOutN.
-func (t *testPayload) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) {
+func (t *testPayload) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
 	panic("not implemented")
 }
 
 // CopyOut implements marshal.Marshallable.CopyOut.
-func (t *testPayload) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) {
+func (t *testPayload) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
 	panic("not implemented")
 }
 
 // CopyIn implements marshal.Marshallable.CopyIn.
-func (t *testPayload) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) {
+func (t *testPayload) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
 	panic("not implemented")
 }
 
diff --git a/pkg/sentry/kernel/task_usermem.go b/pkg/sentry/kernel/task_usermem.go
index 14d765af1..ce134bf54 100644
--- a/pkg/sentry/kernel/task_usermem.go
+++ b/pkg/sentry/kernel/task_usermem.go
@@ -18,6 +18,7 @@ import (
 	"math"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/marshal"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/usermem"
 )
@@ -280,29 +281,29 @@ func (t *Task) IovecsIOSequence(addr usermem.Addr, iovcnt int, opts usermem.IOOp
 	}, nil
 }
 
-// CopyContext wraps a task to allow copying memory to and from the
-// task memory with user specified usermem.IOOpts.
-type CopyContext struct {
+// copyContext implements marshal.CopyContext. It wraps a task to allow copying
+// memory to and from the task memory with custom usermem.IOOpts.
+type copyContext struct {
 	*Task
 	opts usermem.IOOpts
 }
 
 // AsCopyContext wraps the task and returns it as CopyContext.
-func (t *Task) AsCopyContext(opts usermem.IOOpts) *CopyContext {
-	return &CopyContext{t, opts}
+func (t *Task) AsCopyContext(opts usermem.IOOpts) marshal.CopyContext {
+	return &copyContext{t, opts}
 }
 
 // CopyInString copies a string in from the task's memory.
-func (t *CopyContext) CopyInString(addr usermem.Addr, maxLen int) (string, error) {
+func (t *copyContext) CopyInString(addr usermem.Addr, maxLen int) (string, error) {
 	return usermem.CopyStringIn(t, t.MemoryManager(), addr, maxLen, t.opts)
 }
 
 // CopyInBytes copies task memory into dst from an IO context.
-func (t *CopyContext) CopyInBytes(addr usermem.Addr, dst []byte) (int, error) {
+func (t *copyContext) CopyInBytes(addr usermem.Addr, dst []byte) (int, error) {
 	return t.MemoryManager().CopyIn(t, addr, dst, t.opts)
 }
 
 // CopyOutBytes copies src into task memoryfrom an IO context.
-func (t *CopyContext) CopyOutBytes(addr usermem.Addr, src []byte) (int, error) {
+func (t *copyContext) CopyOutBytes(addr usermem.Addr, src []byte) (int, error) {
 	return t.MemoryManager().CopyOut(t, addr, src, t.opts)
 }