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-rwxr-xr-xpkg/sentry/fsimpl/host/host.go41
1 files changed, 32 insertions, 9 deletions
diff --git a/pkg/sentry/fsimpl/host/host.go b/pkg/sentry/fsimpl/host/host.go
index 36bceeaa4..8caf55a1b 100755
--- a/pkg/sentry/fsimpl/host/host.go
+++ b/pkg/sentry/fsimpl/host/host.go
@@ -40,8 +40,20 @@ import (
"gvisor.dev/gvisor/pkg/waiter"
)
-// ImportFD sets up and returns a vfs.FileDescription from a donated fd.
-func ImportFD(ctx context.Context, mnt *vfs.Mount, hostFD int, isTTY bool) (*vfs.FileDescription, error) {
+// NewFDOptions contains options to NewFD.
+type NewFDOptions struct {
+ // If IsTTY is true, the file descriptor is a TTY.
+ IsTTY bool
+
+ // If HaveFlags is true, use Flags for the new file description. Otherwise,
+ // the new file description will inherit flags from hostFD.
+ HaveFlags bool
+ Flags uint32
+}
+
+// NewFD returns a vfs.FileDescription representing the given host file
+// descriptor. mnt must be Kernel.HostMount().
+func NewFD(ctx context.Context, mnt *vfs.Mount, hostFD int, opts *NewFDOptions) (*vfs.FileDescription, error) {
fs, ok := mnt.Filesystem().Impl().(*filesystem)
if !ok {
return nil, fmt.Errorf("can't import host FDs into filesystems of type %T", mnt.Filesystem().Impl())
@@ -53,10 +65,14 @@ func ImportFD(ctx context.Context, mnt *vfs.Mount, hostFD int, isTTY bool) (*vfs
return nil, err
}
- // Get flags for the imported FD.
- flags, err := unix.FcntlInt(uintptr(hostFD), syscall.F_GETFL, 0)
- if err != nil {
- return nil, err
+ flags := opts.Flags
+ if !opts.HaveFlags {
+ // Get flags for the imported FD.
+ flagsInt, err := unix.FcntlInt(uintptr(hostFD), syscall.F_GETFL, 0)
+ if err != nil {
+ return nil, err
+ }
+ flags = uint32(flagsInt)
}
fileMode := linux.FileMode(s.Mode)
@@ -65,13 +81,13 @@ func ImportFD(ctx context.Context, mnt *vfs.Mount, hostFD int, isTTY bool) (*vfs
// Determine if hostFD is seekable. If not, this syscall will return ESPIPE
// (see fs/read_write.c:llseek), e.g. for pipes, sockets, and some character
// devices.
- _, err = unix.Seek(hostFD, 0, linux.SEEK_CUR)
+ _, err := unix.Seek(hostFD, 0, linux.SEEK_CUR)
seekable := err != syserror.ESPIPE
i := &inode{
hostFD: hostFD,
seekable: seekable,
- isTTY: isTTY,
+ isTTY: opts.IsTTY,
canMap: canMap(uint32(fileType)),
wouldBlock: wouldBlock(uint32(fileType)),
ino: fs.NextIno(),
@@ -101,7 +117,14 @@ func ImportFD(ctx context.Context, mnt *vfs.Mount, hostFD int, isTTY bool) (*vfs
// i.open will take a reference on d.
defer d.DecRef()
- return i.open(ctx, d.VFSDentry(), mnt, uint32(flags))
+ return i.open(ctx, d.VFSDentry(), mnt, flags)
+}
+
+// ImportFD sets up and returns a vfs.FileDescription from a donated fd.
+func ImportFD(ctx context.Context, mnt *vfs.Mount, hostFD int, isTTY bool) (*vfs.FileDescription, error) {
+ return NewFD(ctx, mnt, hostFD, &NewFDOptions{
+ IsTTY: isTTY,
+ })
}
// filesystemType implements vfs.FilesystemType.