diff options
Diffstat (limited to 'pkg/sentry/fsimpl/host')
| -rw-r--r-- | pkg/sentry/fsimpl/host/host.go | 53 |
1 files changed, 48 insertions, 5 deletions
diff --git a/pkg/sentry/fsimpl/host/host.go b/pkg/sentry/fsimpl/host/host.go index 05538ea42..33bd205af 100644 --- a/pkg/sentry/fsimpl/host/host.go +++ b/pkg/sentry/fsimpl/host/host.go @@ -24,6 +24,7 @@ import ( "golang.org/x/sys/unix" "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/fdnotifier" "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs" @@ -35,6 +36,7 @@ import ( "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/pkg/waiter" ) // filesystemType implements vfs.FilesystemType. @@ -88,11 +90,12 @@ func ImportFD(ctx context.Context, mnt *vfs.Mount, hostFD int, isTTY bool) (*vfs seekable := err != syserror.ESPIPE i := &inode{ - hostFD: hostFD, - seekable: seekable, - isTTY: isTTY, - canMap: canMap(uint32(fileType)), - ino: fs.NextIno(), + hostFD: hostFD, + seekable: seekable, + isTTY: isTTY, + canMap: canMap(uint32(fileType)), + wouldBlock: wouldBlock(uint32(fileType)), + ino: fs.NextIno(), // For simplicity, set offset to 0. Technically, we should use the existing // offset on the host if the file is seekable. offset: 0, @@ -103,6 +106,17 @@ func ImportFD(ctx context.Context, mnt *vfs.Mount, hostFD int, isTTY bool) (*vfs panic("files that can return EWOULDBLOCK (sockets, pipes, etc.) cannot be memory mapped") } + // If the hostFD would block, we must set it to non-blocking and handle + // blocking behavior in the sentry. + if i.wouldBlock { + if err := syscall.SetNonblock(i.hostFD, true); err != nil { + return nil, err + } + if err := fdnotifier.AddFD(int32(i.hostFD), &i.queue); err != nil { + return nil, err + } + } + d := &kernfs.Dentry{} d.Init(i) // i.open will take a reference on d. @@ -125,6 +139,12 @@ type inode struct { // This field is initialized at creation time and is immutable. hostFD int + // wouldBlock is true if the host FD would return EWOULDBLOCK for + // operations that would block. + // + // This field is initialized at creation time and is immutable. + wouldBlock bool + // seekable is false if the host fd points to a file representing a stream, // e.g. a socket or a pipe. Such files are not seekable and can return // EWOULDBLOCK for I/O operations. @@ -152,6 +172,9 @@ type inode struct { // offset specifies the current file offset. offset int64 + + // Event queue for blocking operations. + queue waiter.Queue } // Note that these flags may become out of date, since they can be modified @@ -354,6 +377,9 @@ func (i *inode) DecRef() { // Destroy implements kernfs.Inode. func (i *inode) Destroy() { + if i.wouldBlock { + fdnotifier.RemoveFD(int32(i.hostFD)) + } if err := unix.Close(i.hostFD); err != nil { log.Warningf("failed to close host fd %d: %v", i.hostFD, err) } @@ -614,3 +640,20 @@ func (f *fileDescription) ConfigureMMap(_ context.Context, opts *memmap.MMapOpts // TODO(gvisor.dev/issue/1672): Implement ConfigureMMap and Mappable interface. return syserror.ENODEV } + +// EventRegister implements waiter.Waitable.EventRegister. +func (f *fileDescription) EventRegister(e *waiter.Entry, mask waiter.EventMask) { + f.inode.queue.EventRegister(e, mask) + fdnotifier.UpdateFD(int32(f.inode.hostFD)) +} + +// EventUnregister implements waiter.Waitable.EventUnregister. +func (f *fileDescription) EventUnregister(e *waiter.Entry) { + f.inode.queue.EventUnregister(e) + fdnotifier.UpdateFD(int32(f.inode.hostFD)) +} + +// Readiness uses the poll() syscall to check the status of the underlying FD. +func (f *fileDescription) Readiness(mask waiter.EventMask) waiter.EventMask { + return fdnotifier.NonBlockingPoll(int32(f.inode.hostFD), mask) +} |