mirror of
https://github.com/netbirdio/gvisor.git
synced 2026-05-22 17:12:49 -07:00
Dean Deng
97 lines
2.7 KiB
Go
97 lines
2.7 KiB
Go
// Copyright 2020 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package host
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import (
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"syscall"
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/context"
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"gvisor.dev/gvisor/pkg/sentry/kernel"
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"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
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"gvisor.dev/gvisor/pkg/sentry/socket/control"
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"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
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"gvisor.dev/gvisor/pkg/sentry/vfs"
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)
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type scmRights struct {
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fds []int
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}
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func newSCMRights(fds []int) control.SCMRightsVFS2 {
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return &scmRights{fds}
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}
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// Files implements control.SCMRights.Files.
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func (c *scmRights) Files(ctx context.Context, max int) (control.RightsFilesVFS2, bool) {
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n := max
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var trunc bool
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if l := len(c.fds); n > l {
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n = l
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} else if n < l {
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trunc = true
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}
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rf := control.RightsFilesVFS2(fdsToFiles(ctx, c.fds[:n]))
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// Only consume converted FDs (fdsToFiles may convert fewer than n FDs).
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c.fds = c.fds[len(rf):]
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return rf, trunc
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}
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// Clone implements transport.RightsControlMessage.Clone.
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func (c *scmRights) Clone() transport.RightsControlMessage {
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// Host rights never need to be cloned.
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return nil
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}
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// Release implements transport.RightsControlMessage.Release.
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func (c *scmRights) Release() {
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for _, fd := range c.fds {
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syscall.Close(fd)
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}
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c.fds = nil
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}
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// If an error is encountered, only files created before the error will be
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// returned. This is what Linux does.
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func fdsToFiles(ctx context.Context, fds []int) []*vfs.FileDescription {
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files := make([]*vfs.FileDescription, 0, len(fds))
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for _, fd := range fds {
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// Get flags. We do it here because they may be modified
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// by subsequent functions.
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fileFlags, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_GETFL, 0)
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if errno != 0 {
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ctx.Warningf("Error retrieving host FD flags: %v", error(errno))
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break
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}
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// Create the file backed by hostFD.
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file, err := ImportFD(ctx, kernel.KernelFromContext(ctx).HostMount(), fd, false /* isTTY */)
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if err != nil {
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ctx.Warningf("Error creating file from host FD: %v", err)
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break
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}
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if err := file.SetStatusFlags(ctx, auth.CredentialsFromContext(ctx), uint32(fileFlags&linux.O_NONBLOCK)); err != nil {
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ctx.Warningf("Error setting flags on host FD file: %v", err)
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break
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}
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files = append(files, file)
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}
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return files
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}
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