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-rw-r--r--pkg/sentry/kernel/fasync/fasync.go8
-rw-r--r--pkg/sentry/syscalls/linux/sys_file.go15
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/fd.go93
-rw-r--r--pkg/sentry/vfs/file_description.go74
4 files changed, 178 insertions, 12 deletions
diff --git a/pkg/sentry/kernel/fasync/fasync.go b/pkg/sentry/kernel/fasync/fasync.go
index d32c3e90a..323f1dfa5 100644
--- a/pkg/sentry/kernel/fasync/fasync.go
+++ b/pkg/sentry/kernel/fasync/fasync.go
@@ -20,15 +20,21 @@ import (
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/waiter"
)
-// New creates a new FileAsync.
+// New creates a new fs.FileAsync.
func New() fs.FileAsync {
return &FileAsync{}
}
+// NewVFS2 creates a new vfs.FileAsync.
+func NewVFS2() vfs.FileAsync {
+ return &FileAsync{}
+}
+
// FileAsync sends signals when the registered file is ready for IO.
//
// +stateify savable
diff --git a/pkg/sentry/syscalls/linux/sys_file.go b/pkg/sentry/syscalls/linux/sys_file.go
index 35eba20c5..2797c6a72 100644
--- a/pkg/sentry/syscalls/linux/sys_file.go
+++ b/pkg/sentry/syscalls/linux/sys_file.go
@@ -900,14 +900,20 @@ func fGetOwn(t *kernel.Task, file *fs.File) int32 {
//
// If who is positive, it represents a PID. If negative, it represents a PGID.
// If the PID or PGID is invalid, the owner is silently unset.
-func fSetOwn(t *kernel.Task, file *fs.File, who int32) {
+func fSetOwn(t *kernel.Task, file *fs.File, who int32) error {
a := file.Async(fasync.New).(*fasync.FileAsync)
if who < 0 {
+ // Check for overflow before flipping the sign.
+ if who-1 > who {
+ return syserror.EINVAL
+ }
pg := t.PIDNamespace().ProcessGroupWithID(kernel.ProcessGroupID(-who))
a.SetOwnerProcessGroup(t, pg)
+ } else {
+ tg := t.PIDNamespace().ThreadGroupWithID(kernel.ThreadID(who))
+ a.SetOwnerThreadGroup(t, tg)
}
- tg := t.PIDNamespace().ThreadGroupWithID(kernel.ThreadID(who))
- a.SetOwnerThreadGroup(t, tg)
+ return nil
}
// Fcntl implements linux syscall fcntl(2).
@@ -1042,8 +1048,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
case linux.F_GETOWN:
return uintptr(fGetOwn(t, file)), nil, nil
case linux.F_SETOWN:
- fSetOwn(t, file, args[2].Int())
- return 0, nil, nil
+ return 0, nil, fSetOwn(t, file, args[2].Int())
case linux.F_GETOWN_EX:
addr := args[2].Pointer()
owner := fGetOwnEx(t, file)
diff --git a/pkg/sentry/syscalls/linux/vfs2/fd.go b/pkg/sentry/syscalls/linux/vfs2/fd.go
index e68b20bed..7e4c6a56e 100644
--- a/pkg/sentry/syscalls/linux/vfs2/fd.go
+++ b/pkg/sentry/syscalls/linux/vfs2/fd.go
@@ -20,6 +20,7 @@ import (
"gvisor.dev/gvisor/pkg/sentry/fs/lock"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs"
"gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/kernel/fasync"
"gvisor.dev/gvisor/pkg/sentry/kernel/pipe"
slinux "gvisor.dev/gvisor/pkg/sentry/syscalls/linux"
"gvisor.dev/gvisor/pkg/sentry/vfs"
@@ -154,6 +155,47 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
return 0, nil, err
}
return uintptr(n), nil, nil
+ case linux.F_GETOWN:
+ a := file.AsyncHandler()
+ if a == nil {
+ return 0, nil, nil
+ }
+ owner := getAsyncOwner(t, a.(*fasync.FileAsync))
+ if owner.Type == linux.F_OWNER_PGRP {
+ return uintptr(-owner.PID), nil, nil
+ }
+ return uintptr(owner.PID), nil, nil
+ case linux.F_SETOWN:
+ who := args[2].Int()
+ ownerType := int32(linux.F_OWNER_PID)
+ if who < 0 {
+ // Check for overflow before flipping the sign.
+ if who-1 > who {
+ return 0, nil, syserror.EINVAL
+ }
+ ownerType = linux.F_OWNER_PGRP
+ who = -who
+ }
+ a := file.SetAsyncHandler(fasync.NewVFS2).(*fasync.FileAsync)
+ return 0, nil, setAsyncOwner(t, a, ownerType, who)
+ case linux.F_GETOWN_EX:
+ a := file.AsyncHandler()
+ if a == nil {
+ return 0, nil, nil
+ }
+ addr := args[2].Pointer()
+ owner := getAsyncOwner(t, a.(*fasync.FileAsync))
+ _, err := t.CopyOut(addr, &owner)
+ return 0, nil, err
+ case linux.F_SETOWN_EX:
+ addr := args[2].Pointer()
+ var owner linux.FOwnerEx
+ n, err := t.CopyIn(addr, &owner)
+ if err != nil {
+ return 0, nil, err
+ }
+ a := file.SetAsyncHandler(fasync.NewVFS2).(*fasync.FileAsync)
+ return uintptr(n), nil, setAsyncOwner(t, a, owner.Type, owner.PID)
case linux.F_GETPIPE_SZ:
pipefile, ok := file.Impl().(*pipe.VFSPipeFD)
if !ok {
@@ -177,6 +219,57 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall
}
}
+func getAsyncOwner(t *kernel.Task, a *fasync.FileAsync) linux.FOwnerEx {
+ ot, otg, opg := a.Owner()
+ switch {
+ case ot != nil:
+ return linux.FOwnerEx{
+ Type: linux.F_OWNER_TID,
+ PID: int32(t.PIDNamespace().IDOfTask(ot)),
+ }
+ case otg != nil:
+ return linux.FOwnerEx{
+ Type: linux.F_OWNER_PID,
+ PID: int32(t.PIDNamespace().IDOfThreadGroup(otg)),
+ }
+ case opg != nil:
+ return linux.FOwnerEx{
+ Type: linux.F_OWNER_PGRP,
+ PID: int32(t.PIDNamespace().IDOfProcessGroup(opg)),
+ }
+ default:
+ return linux.FOwnerEx{}
+ }
+}
+
+func setAsyncOwner(t *kernel.Task, a *fasync.FileAsync, ownerType, pid int32) error {
+ switch ownerType {
+ case linux.F_OWNER_TID:
+ task := t.PIDNamespace().TaskWithID(kernel.ThreadID(pid))
+ if task == nil {
+ return syserror.ESRCH
+ }
+ a.SetOwnerTask(t, task)
+ return nil
+ case linux.F_OWNER_PID:
+ tg := t.PIDNamespace().ThreadGroupWithID(kernel.ThreadID(pid))
+ if tg == nil {
+ return syserror.ESRCH
+ }
+ a.SetOwnerThreadGroup(t, tg)
+ return nil
+ case linux.F_OWNER_PGRP:
+ pg := t.PIDNamespace().ProcessGroupWithID(kernel.ProcessGroupID(pid))
+ if pg == nil {
+ return syserror.ESRCH
+ }
+ a.SetOwnerProcessGroup(t, pg)
+ return nil
+ default:
+ return syserror.EINVAL
+ }
+}
+
func posixLock(t *kernel.Task, args arch.SyscallArguments, file *vfs.FileDescription, cmd int32) error {
// Copy in the lock request.
flockAddr := args[2].Pointer()
diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go
index e0538ea53..cd1db14ac 100644
--- a/pkg/sentry/vfs/file_description.go
+++ b/pkg/sentry/vfs/file_description.go
@@ -42,11 +42,20 @@ type FileDescription struct {
// operations.
refs int64
+ // flagsMu protects statusFlags and asyncHandler below.
+ flagsMu sync.Mutex
+
// statusFlags contains status flags, "initialized by open(2) and possibly
- // modified by fcntl()" - fcntl(2). statusFlags is accessed using atomic
- // memory operations.
+ // modified by fcntl()" - fcntl(2). statusFlags can be read using atomic
+ // memory operations when it does not need to be synchronized with an
+ // access to asyncHandler.
statusFlags uint32
+ // asyncHandler handles O_ASYNC signal generation. It is set with the
+ // F_SETOWN or F_SETOWN_EX fcntls. For asyncHandler to be used, O_ASYNC must
+ // also be set by fcntl(2).
+ asyncHandler FileAsync
+
// epolls is the set of epollInterests registered for this FileDescription.
// epolls is protected by epollMu.
epollMu sync.Mutex
@@ -193,6 +202,13 @@ func (fd *FileDescription) DecRef() {
fd.vd.mount.EndWrite()
}
fd.vd.DecRef()
+ fd.flagsMu.Lock()
+ // TODO(gvisor.dev/issue/1663): We may need to unregister during save, as we do in VFS1.
+ if fd.statusFlags&linux.O_ASYNC != 0 && fd.asyncHandler != nil {
+ fd.asyncHandler.Unregister(fd)
+ }
+ fd.asyncHandler = nil
+ fd.flagsMu.Unlock()
} else if refs < 0 {
panic("FileDescription.DecRef() called without holding a reference")
}
@@ -276,7 +292,18 @@ func (fd *FileDescription) SetStatusFlags(ctx context.Context, creds *auth.Crede
}
// TODO(jamieliu): FileDescriptionImpl.SetOAsync()?
const settableFlags = linux.O_APPEND | linux.O_ASYNC | linux.O_DIRECT | linux.O_NOATIME | linux.O_NONBLOCK
- atomic.StoreUint32(&fd.statusFlags, (oldFlags&^settableFlags)|(flags&settableFlags))
+ fd.flagsMu.Lock()
+ if fd.asyncHandler != nil {
+ // Use fd.statusFlags instead of oldFlags, which may have become outdated,
+ // to avoid double registering/unregistering.
+ if fd.statusFlags&linux.O_ASYNC == 0 && flags&linux.O_ASYNC != 0 {
+ fd.asyncHandler.Register(fd)
+ } else if fd.statusFlags&linux.O_ASYNC != 0 && flags&linux.O_ASYNC == 0 {
+ fd.asyncHandler.Unregister(fd)
+ }
+ }
+ fd.statusFlags = (oldFlags &^ settableFlags) | (flags & settableFlags)
+ fd.flagsMu.Unlock()
return nil
}
@@ -533,17 +560,23 @@ func (fd *FileDescription) StatFS(ctx context.Context) (linux.Statfs, error) {
return fd.impl.StatFS(ctx)
}
-// Readiness returns fd's I/O readiness.
+// Readiness implements waiter.Waitable.Readiness.
+//
+// It returns fd's I/O readiness.
func (fd *FileDescription) Readiness(mask waiter.EventMask) waiter.EventMask {
return fd.impl.Readiness(mask)
}
-// EventRegister registers e for I/O readiness events in mask.
+// EventRegister implements waiter.Waitable.EventRegister.
+//
+// It registers e for I/O readiness events in mask.
func (fd *FileDescription) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
fd.impl.EventRegister(e, mask)
}
-// EventUnregister unregisters e for I/O readiness events.
+// EventUnregister implements waiter.Waitable.EventUnregister.
+//
+// It unregisters e for I/O readiness events.
func (fd *FileDescription) EventUnregister(e *waiter.Entry) {
fd.impl.EventUnregister(e)
}
@@ -770,3 +803,32 @@ func (fd *FileDescription) LockPOSIX(ctx context.Context, uid lock.UniqueID, t l
func (fd *FileDescription) UnlockPOSIX(ctx context.Context, uid lock.UniqueID, start, end uint64, whence int16) error {
return fd.impl.UnlockPOSIX(ctx, uid, start, end, whence)
}
+
+// A FileAsync sends signals to its owner when w is ready for IO. This is only
+// implemented by pkg/sentry/fasync:FileAsync, but we unfortunately need this
+// interface to avoid circular dependencies.
+type FileAsync interface {
+ Register(w waiter.Waitable)
+ Unregister(w waiter.Waitable)
+}
+
+// AsyncHandler returns the FileAsync for fd.
+func (fd *FileDescription) AsyncHandler() FileAsync {
+ fd.flagsMu.Lock()
+ defer fd.flagsMu.Unlock()
+ return fd.asyncHandler
+}
+
+// SetAsyncHandler sets fd.asyncHandler if it has not been set before and
+// returns it.
+func (fd *FileDescription) SetAsyncHandler(newHandler func() FileAsync) FileAsync {
+ fd.flagsMu.Lock()
+ defer fd.flagsMu.Unlock()
+ if fd.asyncHandler == nil {
+ fd.asyncHandler = newHandler()
+ if fd.statusFlags&linux.O_ASYNC != 0 {
+ fd.asyncHandler.Register(fd)
+ }
+ }
+ return fd.asyncHandler
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 11:27:24 +0000