github.com/nicocha30/gvisor-ligolo@v0.0.0-20230726075806-989fa2c0a413/pkg/sentry/devices/accel/device.go (about)

     1  // Copyright 2023 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //	http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package accel
    16  
    17  import (
    18  	"fmt"
    19  
    20  	"golang.org/x/sys/unix"
    21  	"github.com/nicocha30/gvisor-ligolo/pkg/abi/linux"
    22  	"github.com/nicocha30/gvisor-ligolo/pkg/context"
    23  	"github.com/nicocha30/gvisor-ligolo/pkg/sentry/fsimpl/devtmpfs"
    24  	"github.com/nicocha30/gvisor-ligolo/pkg/sentry/vfs"
    25  )
    26  
    27  // accelDevice implements vfs.Device for /dev/accel[0-9]+.
    28  //
    29  // +stateify savable
    30  type accelDevice struct {
    31  	minor uint32
    32  }
    33  
    34  func (dev *accelDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
    35  	hostPath := fmt.Sprintf("/dev/accel%d", dev.minor)
    36  	hostFD, err := unix.Openat(-1, hostPath, int((opts.Flags&unix.O_ACCMODE)|unix.O_NOFOLLOW), 0)
    37  	if err != nil {
    38  		ctx.Warningf("accelDevice: failed to open host %s: %v", hostPath, err)
    39  		return nil, err
    40  	}
    41  	fd := &accelFD{
    42  		hostFD: int32(hostFD),
    43  	}
    44  	if err := fd.vfsfd.Init(fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{
    45  		UseDentryMetadata: true,
    46  	}); err != nil {
    47  		unix.Close(hostFD)
    48  		return nil, err
    49  	}
    50  	return &fd.vfsfd, nil
    51  }
    52  
    53  // CreateDevtmpfsFile creates a /dev/accel[0-9]+ device file.
    54  func CreateDevtmpfsFile(ctx context.Context, dev *devtmpfs.Accessor, num uint32) error {
    55  	return dev.CreateDeviceFile(ctx, fmt.Sprintf("accel%d", num), vfs.CharDevice, linux.ACCEL_MAJOR, num, 0666)
    56  }
    57  
    58  // Register registers all devices implemented by this package in vfsObj.
    59  func Register(vfsObj *vfs.VirtualFilesystem, minor uint32) error {
    60  	return vfsObj.RegisterDevice(vfs.CharDevice, linux.ACCEL_MAJOR, minor, &accelDevice{
    61  		minor: minor,
    62  	}, &vfs.RegisterDeviceOptions{
    63  		GroupName: "accel",
    64  	})
    65  }