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-rw-r--r--pkg/sentry/fsimpl/fuse/BUILD2
-rw-r--r--pkg/sentry/fsimpl/fuse/connection.go264
-rw-r--r--pkg/sentry/fsimpl/fuse/connection_control.go (renamed from pkg/sentry/fsimpl/fuse/init.go)98
-rw-r--r--pkg/sentry/fsimpl/fuse/dev_test.go2
-rw-r--r--pkg/sentry/fsimpl/fuse/fusefs.go25
-rw-r--r--pkg/sentry/fsimpl/fuse/request_response.go150
6 files changed, 273 insertions, 268 deletions
diff --git a/pkg/sentry/fsimpl/fuse/BUILD b/pkg/sentry/fsimpl/fuse/BUILD
index 86dc6a7a4..23660a708 100644
--- a/pkg/sentry/fsimpl/fuse/BUILD
+++ b/pkg/sentry/fsimpl/fuse/BUILD
@@ -30,11 +30,11 @@ go_library(
name = "fuse",
srcs = [
"connection.go",
+ "connection_control.go",
"dev.go",
"directory.go",
"file.go",
"fusefs.go",
- "init.go",
"inode_refs.go",
"read_write.go",
"register.go",
diff --git a/pkg/sentry/fsimpl/fuse/connection.go b/pkg/sentry/fsimpl/fuse/connection.go
index 8dd86afad..9d72b927f 100644
--- a/pkg/sentry/fsimpl/fuse/connection.go
+++ b/pkg/sentry/fsimpl/fuse/connection.go
@@ -16,31 +16,17 @@ package fuse
import (
"errors"
- "fmt"
"sync"
- "sync/atomic"
- "syscall"
-
- "gvisor.dev/gvisor/tools/go_marshal/marshal"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/log"
"gvisor.dev/gvisor/pkg/sentry/kernel"
- "gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/syserror"
"gvisor.dev/gvisor/pkg/waiter"
)
-// maxActiveRequestsDefault is the default setting controlling the upper bound
-// on the number of active requests at any given time.
-const maxActiveRequestsDefault = 10000
-
-// Ordinary requests have even IDs, while interrupts IDs are odd.
-// Used to increment the unique ID for each FUSE request.
-var reqIDStep uint64 = 2
-
const (
// fuseDefaultMaxBackground is the default value for MaxBackground.
fuseDefaultMaxBackground = 12
@@ -53,33 +39,11 @@ const (
fuseDefaultMaxPagesPerReq = 32
)
-// Request represents a FUSE operation request that hasn't been sent to the
-// server yet.
-//
-// +stateify savable
-type Request struct {
- requestEntry
-
- id linux.FUSEOpID
- hdr *linux.FUSEHeaderIn
- data []byte
-
- // payload for this request: extra bytes to write after
- // the data slice. Used by FUSE_WRITE.
- payload []byte
-}
-
-// Response represents an actual response from the server, including the
-// response payload.
-//
-// +stateify savable
-type Response struct {
- opcode linux.FUSEOpcode
- hdr linux.FUSEHeaderOut
- data []byte
-}
-
// connection is the struct by which the sentry communicates with the FUSE server daemon.
+// Lock order:
+// - conn.fd.mu
+// - conn.mu
+// - conn.asyncMu
type connection struct {
fd *DeviceFD
@@ -114,10 +78,6 @@ type connection struct {
// initializedChan is used to block requests before initialization.
initializedChan chan struct{}
- // blocked when there are too many outstading backgrounds requests (NumBackground == MaxBackground).
- // TODO(gvisor.dev/issue/3185): update the numBackground accordingly; use a channel to block.
- blocked bool
-
// connected (connection established) when a new FUSE file system is created.
// Set to false when:
// umount,
@@ -125,51 +85,52 @@ type connection struct {
// device release.
connected bool
- // aborted via sysfs.
- // TODO(gvisor.dev/issue/3185): abort all queued requests.
- aborted bool
-
- // atomicOTrunc is true when FUSE does not send a separate SETATTR request
- // before open with O_TRUNC flag.
- // Negotiated and only set in INIT.
- atomicOTrunc bool
-
// connInitError if FUSE_INIT encountered error (major version mismatch).
// Only set in INIT.
connInitError bool
// connInitSuccess if FUSE_INIT is successful.
// Only set in INIT.
- // Used for destory.
+ // Used for destory (not yet implemented).
connInitSuccess bool
- // TODO(gvisor.dev/issue/3185): All the queue logic are working in progress.
-
- // NumberBackground is the number of requests in the background.
- numBackground uint16
+ // aborted via sysfs, and will send ECONNABORTED to read after disconnection (instead of ENODEV).
+ // Set only if abortErr is true and via fuse control fs (not yet implemented).
+ // TODO(gvisor.dev/issue/3525): set this to true when user aborts.
+ aborted bool
- // congestionThreshold for NumBackground.
- // Negotiated in FUSE_INIT.
- congestionThreshold uint16
+ // numWating is the number of requests waiting to be
+ // sent to FUSE device or being processed by FUSE daemon.
+ numWaiting uint32
- // maxBackground is the maximum number of NumBackground.
- // Block connection when it is reached.
- // Negotiated in FUSE_INIT.
- maxBackground uint16
+ // Terminology note:
+ //
+ // - `asyncNumMax` is the `MaxBackground` in the FUSE_INIT_IN struct.
+ //
+ // - `asyncCongestionThreshold` is the `CongestionThreshold` in the FUSE_INIT_IN struct.
+ //
+ // We call the "background" requests in unix term as async requests.
+ // The "async requests" in unix term is our async requests that expect a reply,
+ // i.e. `!requestOptions.noReply`
- // numActiveBackground is the number of requests in background and has being marked as active.
- numActiveBackground uint16
+ // asyncMu protects the async request fields.
+ asyncMu sync.Mutex
- // numWating is the number of requests waiting for completion.
- numWaiting uint32
+ // asyncNum is the number of async requests.
+ // Protected by asyncMu.
+ asyncNum uint16
- // TODO(gvisor.dev/issue/3185): BgQueue
- // some queue for background queued requests.
+ // asyncCongestionThreshold the number of async requests.
+ // Negotiated in FUSE_INIT as "CongestionThreshold".
+ // TODO(gvisor.dev/issue/3529): add congestion control.
+ // Protected by asyncMu.
+ asyncCongestionThreshold uint16
- // bgLock protects:
- // MaxBackground, CongestionThreshold, NumBackground,
- // NumActiveBackground, BgQueue, Blocked.
- bgLock sync.Mutex
+ // asyncNumMax is the maximum number of asyncNum.
+ // Connection blocks the async requests when it is reached.
+ // Negotiated in FUSE_INIT as "MaxBackground".
+ // Protected by asyncMu.
+ asyncNumMax uint16
// maxRead is the maximum size of a read buffer in in bytes.
// Initialized from a fuse fs parameter.
@@ -187,6 +148,11 @@ type connection struct {
// Negotiated and only set in INIT.
minor uint32
+ // atomicOTrunc is true when FUSE does not send a separate SETATTR request
+ // before open with O_TRUNC flag.
+ // Negotiated and only set in INIT.
+ atomicOTrunc bool
+
// asyncRead if read pages asynchronously.
// Negotiated and only set in INIT.
asyncRead bool
@@ -224,63 +190,13 @@ func newFUSEConnection(_ context.Context, fd *vfs.FileDescription, opts *filesys
fuseFD.writeCursor = 0
return &connection{
- fd: fuseFD,
- maxBackground: fuseDefaultMaxBackground,
- congestionThreshold: fuseDefaultCongestionThreshold,
- maxRead: opts.maxRead,
- maxPages: fuseDefaultMaxPagesPerReq,
- initializedChan: make(chan struct{}),
- connected: true,
- }, nil
-}
-
-// SetInitialized atomically sets the connection as initialized.
-func (conn *connection) SetInitialized() {
- // Unblock the requests sent before INIT.
- close(conn.initializedChan)
-
- // Close the channel first to avoid the non-atomic situation
- // where conn.initialized is true but there are
- // tasks being blocked on the channel.
- // And it prevents the newer tasks from gaining
- // unnecessary higher chance to be issued before the blocked one.
-
- atomic.StoreInt32(&(conn.initialized), int32(1))
-}
-
-// IsInitialized atomically check if the connection is initialized.
-// pairs with SetInitialized().
-func (conn *connection) Initialized() bool {
- return atomic.LoadInt32(&(conn.initialized)) != 0
-}
-
-// NewRequest creates a new request that can be sent to the FUSE server.
-func (conn *connection) NewRequest(creds *auth.Credentials, pid uint32, ino uint64, opcode linux.FUSEOpcode, payload marshal.Marshallable) (*Request, error) {
- conn.fd.mu.Lock()
- defer conn.fd.mu.Unlock()
- conn.fd.nextOpID += linux.FUSEOpID(reqIDStep)
-
- hdrLen := (*linux.FUSEHeaderIn)(nil).SizeBytes()
- hdr := linux.FUSEHeaderIn{
- Len: uint32(hdrLen + payload.SizeBytes()),
- Opcode: opcode,
- Unique: conn.fd.nextOpID,
- NodeID: ino,
- UID: uint32(creds.EffectiveKUID),
- GID: uint32(creds.EffectiveKGID),
- PID: pid,
- }
-
- buf := make([]byte, hdr.Len)
-
- // TODO(gVisor.dev/3698): Use the unsafe version once go_marshal is safe to use again.
- hdr.MarshalBytes(buf[:hdrLen])
- payload.MarshalBytes(buf[hdrLen:])
-
- return &Request{
- id: hdr.Unique,
- hdr: &hdr,
- data: buf,
+ fd: fuseFD,
+ asyncNumMax: fuseDefaultMaxBackground,
+ asyncCongestionThreshold: fuseDefaultCongestionThreshold,
+ maxRead: opts.maxRead,
+ maxPages: fuseDefaultMaxPagesPerReq,
+ initializedChan: make(chan struct{}),
+ connected: true,
}, nil
}
@@ -336,43 +252,6 @@ func (conn *connection) call(t *kernel.Task, r *Request) (*Response, error) {
return fut.resolve(t)
}
-// Error returns the error of the FUSE call.
-func (r *Response) Error() error {
- errno := r.hdr.Error
- if errno >= 0 {
- return nil
- }
-
- sysErrNo := syscall.Errno(-errno)
- return error(sysErrNo)
-}
-
-// DataLen returns the size of the response without the header.
-func (r *Response) DataLen() uint32 {
- return r.hdr.Len - uint32(r.hdr.SizeBytes())
-}
-
-// UnmarshalPayload unmarshals the response data into m.
-func (r *Response) UnmarshalPayload(m marshal.Marshallable) error {
- hdrLen := r.hdr.SizeBytes()
- haveDataLen := r.hdr.Len - uint32(hdrLen)
- wantDataLen := uint32(m.SizeBytes())
-
- if haveDataLen < wantDataLen {
- return fmt.Errorf("payload too small. Minimum data lenth required: %d, but got data length %d", wantDataLen, haveDataLen)
- }
-
- // The response data is empty unless there is some payload. And so, doesn't
- // need to be unmarshalled.
- if r.data == nil {
- return nil
- }
-
- // TODO(gVisor.dev/3698): Use the unsafe version once go_marshal is safe to use again.
- m.UnmarshalBytes(r.data[hdrLen:])
- return nil
-}
-
// callFuture makes a request to the server and returns a future response.
// Call resolve() when the response needs to be fulfilled.
func (conn *connection) callFuture(t *kernel.Task, r *Request) (*futureResponse, error) {
@@ -421,50 +300,3 @@ func (conn *connection) callFutureLocked(t *kernel.Task, r *Request) (*futureRes
return fut, nil
}
-
-// futureResponse represents an in-flight request, that may or may not have
-// completed yet. Convert it to a resolved Response by calling Resolve, but note
-// that this may block.
-//
-// +stateify savable
-type futureResponse struct {
- opcode linux.FUSEOpcode
- ch chan struct{}
- hdr *linux.FUSEHeaderOut
- data []byte
-}
-
-// newFutureResponse creates a future response to a FUSE request.
-func newFutureResponse(opcode linux.FUSEOpcode) *futureResponse {
- return &futureResponse{
- opcode: opcode,
- ch: make(chan struct{}),
- }
-}
-
-// resolve blocks the task until the server responds to its corresponding request,
-// then returns a resolved response.
-func (f *futureResponse) resolve(t *kernel.Task) (*Response, error) {
- // If there is no Task associated with this request - then we don't try to resolve
- // the response. Instead, the task writing the response (proxy to the server) will
- // process the response on our behalf.
- if t == nil {
- log.Infof("fuse.Response.resolve: Not waiting on a response from server.")
- return nil, nil
- }
-
- if err := t.Block(f.ch); err != nil {
- return nil, err
- }
-
- return f.getResponse(), nil
-}
-
-// getResponse creates a Response from the data the futureResponse has.
-func (f *futureResponse) getResponse() *Response {
- return &Response{
- opcode: f.opcode,
- hdr: *f.hdr,
- data: f.data,
- }
-}
diff --git a/pkg/sentry/fsimpl/fuse/init.go b/pkg/sentry/fsimpl/fuse/connection_control.go
index a47309b6e..d84d9caf2 100644
--- a/pkg/sentry/fsimpl/fuse/init.go
+++ b/pkg/sentry/fsimpl/fuse/connection_control.go
@@ -15,6 +15,8 @@
package fuse
import (
+ "sync/atomic"
+
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
)
@@ -50,6 +52,26 @@ var (
MaxUserCongestionThreshold uint16 = fuseDefaultCongestionThreshold
)
+// SetInitialized atomically sets the connection as initialized.
+func (conn *connection) SetInitialized() {
+ // Unblock the requests sent before INIT.
+ close(conn.initializedChan)
+
+ // Close the channel first to avoid the non-atomic situation
+ // where conn.initialized is true but there are
+ // tasks being blocked on the channel.
+ // And it prevents the newer tasks from gaining
+ // unnecessary higher chance to be issued before the blocked one.
+
+ atomic.StoreInt32(&(conn.initialized), int32(1))
+}
+
+// IsInitialized atomically check if the connection is initialized.
+// pairs with SetInitialized().
+func (conn *connection) Initialized() bool {
+ return atomic.LoadInt32(&(conn.initialized)) != 0
+}
+
// InitSend sends a FUSE_INIT request.
func (conn *connection) InitSend(creds *auth.Credentials, pid uint32) error {
in := linux.FUSEInitIn{
@@ -85,15 +107,15 @@ func (conn *connection) InitRecv(res *Response, hasSysAdminCap bool) error {
}
// Process the FUSE_INIT reply from the FUSE server.
+// It tries to acquire the conn.asyncMu lock if minor version is newer than 13.
func (conn *connection) initProcessReply(out *linux.FUSEInitOut, hasSysAdminCap bool) error {
+ // No matter error or not, always set initialzied.
+ // to unblock the blocked requests.
+ defer conn.SetInitialized()
+
// No support for old major fuse versions.
if out.Major != linux.FUSE_KERNEL_VERSION {
conn.connInitError = true
-
- // Set the connection as initialized and unblock the blocked requests
- // (i.e. return error for them).
- conn.SetInitialized()
-
return nil
}
@@ -101,29 +123,14 @@ func (conn *connection) initProcessReply(out *linux.FUSEInitOut, hasSysAdminCap
conn.connInitSuccess = true
conn.minor = out.Minor
- // No support for limits before minor version 13.
- if out.Minor >= 13 {
- conn.bgLock.Lock()
-
- if out.MaxBackground > 0 {
- conn.maxBackground = out.MaxBackground
-
- if !hasSysAdminCap &&
- conn.maxBackground > MaxUserBackgroundRequest {
- conn.maxBackground = MaxUserBackgroundRequest
- }
- }
-
- if out.CongestionThreshold > 0 {
- conn.congestionThreshold = out.CongestionThreshold
-
- if !hasSysAdminCap &&
- conn.congestionThreshold > MaxUserCongestionThreshold {
- conn.congestionThreshold = MaxUserCongestionThreshold
- }
- }
-
- conn.bgLock.Unlock()
+ // No support for negotiating MaxWrite before minor version 5.
+ if out.Minor >= 5 {
+ conn.maxWrite = out.MaxWrite
+ } else {
+ conn.maxWrite = fuseMinMaxWrite
+ }
+ if conn.maxWrite < fuseMinMaxWrite {
+ conn.maxWrite = fuseMinMaxWrite
}
// No support for the following flags before minor version 6.
@@ -147,19 +154,30 @@ func (conn *connection) initProcessReply(out *linux.FUSEInitOut, hasSysAdminCap
}
}
- // No support for negotiating MaxWrite before minor version 5.
- if out.Minor >= 5 {
- conn.maxWrite = out.MaxWrite
- } else {
- conn.maxWrite = fuseMinMaxWrite
- }
- if conn.maxWrite < fuseMinMaxWrite {
- conn.maxWrite = fuseMinMaxWrite
- }
+ // No support for limits before minor version 13.
+ if out.Minor >= 13 {
+ conn.asyncMu.Lock()
+
+ if out.MaxBackground > 0 {
+ conn.asyncNumMax = out.MaxBackground
+
+ if !hasSysAdminCap &&
+ conn.asyncNumMax > MaxUserBackgroundRequest {
+ conn.asyncNumMax = MaxUserBackgroundRequest
+ }
+ }
- // Set connection as initialized and unblock the requests
- // issued before init.
- conn.SetInitialized()
+ if out.CongestionThreshold > 0 {
+ conn.asyncCongestionThreshold = out.CongestionThreshold
+
+ if !hasSysAdminCap &&
+ conn.asyncCongestionThreshold > MaxUserCongestionThreshold {
+ conn.asyncCongestionThreshold = MaxUserCongestionThreshold
+ }
+ }
+
+ conn.asyncMu.Unlock()
+ }
return nil
}
diff --git a/pkg/sentry/fsimpl/fuse/dev_test.go b/pkg/sentry/fsimpl/fuse/dev_test.go
index aedc2fa39..936683454 100644
--- a/pkg/sentry/fsimpl/fuse/dev_test.go
+++ b/pkg/sentry/fsimpl/fuse/dev_test.go
@@ -369,7 +369,7 @@ func newTestConnection(system *testutil.System, k *kernel.Kernel, maxActiveReque
fsopts := filesystemOptions{
maxActiveRequests: maxActiveRequests,
}
- fs, err := NewFUSEFilesystem(system.Ctx, 0, &fsopts, &fuseDev.vfsfd)
+ fs, err := newFUSEFilesystem(system.Ctx, 0, &fsopts, &fuseDev.vfsfd)
if err != nil {
return nil, nil, err
}
diff --git a/pkg/sentry/fsimpl/fuse/fusefs.go b/pkg/sentry/fsimpl/fuse/fusefs.go
index 572245303..30725182a 100644
--- a/pkg/sentry/fsimpl/fuse/fusefs.go
+++ b/pkg/sentry/fsimpl/fuse/fusefs.go
@@ -35,6 +35,10 @@ import (
// Name is the default filesystem name.
const Name = "fuse"
+// maxActiveRequestsDefault is the default setting controlling the upper bound
+// on the number of active requests at any given time.
+const maxActiveRequestsDefault = 10000
+
// FilesystemType implements vfs.FilesystemType.
type FilesystemType struct{}
@@ -168,12 +172,12 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
// Check for unparsed options.
if len(mopts) != 0 {
- log.Warningf("%s.GetFilesystem: unknown options: %v", fsType.Name(), mopts)
+ log.Warningf("%s.GetFilesystem: unsupported or unknown options: %v", fsType.Name(), mopts)
return nil, nil, syserror.EINVAL
}
// Create a new FUSE filesystem.
- fs, err := NewFUSEFilesystem(ctx, devMinor, &fsopts, fuseFd)
+ fs, err := newFUSEFilesystem(ctx, devMinor, &fsopts, fuseFd)
if err != nil {
log.Warningf("%s.NewFUSEFilesystem: failed with error: %v", fsType.Name(), err)
return nil, nil, err
@@ -194,21 +198,22 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
return fs.VFSFilesystem(), root.VFSDentry(), nil
}
-// NewFUSEFilesystem creates a new FUSE filesystem.
-func NewFUSEFilesystem(ctx context.Context, devMinor uint32, opts *filesystemOptions, device *vfs.FileDescription) (*filesystem, error) {
- fs := &filesystem{
- devMinor: devMinor,
- opts: opts,
- }
-
+// newFUSEFilesystem creates a new FUSE filesystem.
+func newFUSEFilesystem(ctx context.Context, devMinor uint32, opts *filesystemOptions, device *vfs.FileDescription) (*filesystem, error) {
conn, err := newFUSEConnection(ctx, device, opts)
if err != nil {
log.Warningf("fuse.NewFUSEFilesystem: NewFUSEConnection failed with error: %v", err)
return nil, syserror.EINVAL
}
- fs.conn = conn
fuseFD := device.Impl().(*DeviceFD)
+
+ fs := &filesystem{
+ devMinor: devMinor,
+ opts: opts,
+ conn: conn,
+ }
+
fuseFD.fs = fs
return fs, nil
diff --git a/pkg/sentry/fsimpl/fuse/request_response.go b/pkg/sentry/fsimpl/fuse/request_response.go
index a69b21221..648eaf263 100644
--- a/pkg/sentry/fsimpl/fuse/request_response.go
+++ b/pkg/sentry/fsimpl/fuse/request_response.go
@@ -15,7 +15,13 @@
package fuse
import (
+ "fmt"
+ "syscall"
+
"gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/log"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/usermem"
"gvisor.dev/gvisor/tools/go_marshal/marshal"
)
@@ -71,3 +77,147 @@ func (r *fuseInitRes) UnmarshalBytes(src []byte) {
func (r *fuseInitRes) SizeBytes() int {
return int(r.initLen)
}
+
+// Ordinary requests have even IDs, while interrupts IDs are odd.
+// Used to increment the unique ID for each FUSE request.
+var reqIDStep uint64 = 2
+
+// Request represents a FUSE operation request that hasn't been sent to the
+// server yet.
+//
+// +stateify savable
+type Request struct {
+ requestEntry
+
+ id linux.FUSEOpID
+ hdr *linux.FUSEHeaderIn
+ data []byte
+
+ // payload for this request: extra bytes to write after
+ // the data slice. Used by FUSE_WRITE.
+ payload []byte
+}
+
+// NewRequest creates a new request that can be sent to the FUSE server.
+func (conn *connection) NewRequest(creds *auth.Credentials, pid uint32, ino uint64, opcode linux.FUSEOpcode, payload marshal.Marshallable) (*Request, error) {
+ conn.fd.mu.Lock()
+ defer conn.fd.mu.Unlock()
+ conn.fd.nextOpID += linux.FUSEOpID(reqIDStep)
+
+ hdrLen := (*linux.FUSEHeaderIn)(nil).SizeBytes()
+ hdr := linux.FUSEHeaderIn{
+ Len: uint32(hdrLen + payload.SizeBytes()),
+ Opcode: opcode,
+ Unique: conn.fd.nextOpID,
+ NodeID: ino,
+ UID: uint32(creds.EffectiveKUID),
+ GID: uint32(creds.EffectiveKGID),
+ PID: pid,
+ }
+
+ buf := make([]byte, hdr.Len)
+
+ // TODO(gVisor.dev/3698): Use the unsafe version once go_marshal is safe to use again.
+ hdr.MarshalBytes(buf[:hdrLen])
+ payload.MarshalBytes(buf[hdrLen:])
+
+ return &Request{
+ id: hdr.Unique,
+ hdr: &hdr,
+ data: buf,
+ }, nil
+}
+
+// futureResponse represents an in-flight request, that may or may not have
+// completed yet. Convert it to a resolved Response by calling Resolve, but note
+// that this may block.
+//
+// +stateify savable
+type futureResponse struct {
+ opcode linux.FUSEOpcode
+ ch chan struct{}
+ hdr *linux.FUSEHeaderOut
+ data []byte
+}
+
+// newFutureResponse creates a future response to a FUSE request.
+func newFutureResponse(opcode linux.FUSEOpcode) *futureResponse {
+ return &futureResponse{
+ opcode: opcode,
+ ch: make(chan struct{}),
+ }
+}
+
+// resolve blocks the task until the server responds to its corresponding request,
+// then returns a resolved response.
+func (f *futureResponse) resolve(t *kernel.Task) (*Response, error) {
+ // If there is no Task associated with this request - then we don't try to resolve
+ // the response. Instead, the task writing the response (proxy to the server) will
+ // process the response on our behalf.
+ if t == nil {
+ log.Infof("fuse.Response.resolve: Not waiting on a response from server.")
+ return nil, nil
+ }
+
+ if err := t.Block(f.ch); err != nil {
+ return nil, err
+ }
+
+ return f.getResponse(), nil
+}
+
+// getResponse creates a Response from the data the futureResponse has.
+func (f *futureResponse) getResponse() *Response {
+ return &Response{
+ opcode: f.opcode,
+ hdr: *f.hdr,
+ data: f.data,
+ }
+}
+
+// Response represents an actual response from the server, including the
+// response payload.
+//
+// +stateify savable
+type Response struct {
+ opcode linux.FUSEOpcode
+ hdr linux.FUSEHeaderOut
+ data []byte
+}
+
+// Error returns the error of the FUSE call.
+func (r *Response) Error() error {
+ errno := r.hdr.Error
+ if errno >= 0 {
+ return nil
+ }
+
+ sysErrNo := syscall.Errno(-errno)
+ return error(sysErrNo)
+}
+
+// DataLen returns the size of the response without the header.
+func (r *Response) DataLen() uint32 {
+ return r.hdr.Len - uint32(r.hdr.SizeBytes())
+}
+
+// UnmarshalPayload unmarshals the response data into m.
+func (r *Response) UnmarshalPayload(m marshal.Marshallable) error {
+ hdrLen := r.hdr.SizeBytes()
+ haveDataLen := r.hdr.Len - uint32(hdrLen)
+ wantDataLen := uint32(m.SizeBytes())
+
+ if haveDataLen < wantDataLen {
+ return fmt.Errorf("payload too small. Minimum data lenth required: %d, but got data length %d", wantDataLen, haveDataLen)
+ }
+
+ // The response data is empty unless there is some payload. And so, doesn't
+ // need to be unmarshalled.
+ if r.data == nil {
+ return nil
+ }
+
+ // TODO(gVisor.dev/3698): Use the unsafe version once go_marshal is safe to use again.
+ m.UnmarshalBytes(r.data[hdrLen:])
+ return nil
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-03 11:34:42 +0000