39 lines
1.2 KiB
Go
39 lines
1.2 KiB
Go
/*
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Copyright The containerd Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package sys
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import (
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"fmt"
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"os"
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"syscall"
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"golang.org/x/sys/unix"
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)
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// GetUsernsForNamespace returns a file descriptor that refers to the owning
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// user namespace for the namespace referred to by fd.
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//
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// REF: https://man7.org/linux/man-pages/man2/ioctl_ns.2.html
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func GetUsernsForNamespace(fd uintptr) (*os.File, error) {
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fd, _, errno := unix.Syscall(syscall.SYS_IOCTL, fd, uintptr(unix.NS_GET_USERNS), 0)
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if errno != 0 {
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return nil, fmt.Errorf("failed to get user namespace fd: %w", errno)
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}
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return os.NewFile(fd, fmt.Sprintf("/proc/%d/fd/%d", os.Getpid(), fd)), nil
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}
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