mirror of
https://github.com/opencontainers/runc.git
synced 2026-07-11 06:03:57 +08:00
Kir Kolyshkin
c84a878cac
Apparently Write (and WriteString) must return an error (apparently io.ErrShortWrite) on short writes (see [1], [2]), so no explicit check for a short write is needed. While at it, use (*os.File).WriteString directly rather than io.WriteString. [1]: https://pkg.go.dev/os#File.Write [2]: https://pkg.go.dev/io#Writer Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
51 lines
1.3 KiB
Go
51 lines
1.3 KiB
Go
package sys
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import (
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"fmt"
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"os"
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"strings"
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"golang.org/x/sys/unix"
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"github.com/cyphar/filepath-securejoin/pathrs-lite"
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"github.com/cyphar/filepath-securejoin/pathrs-lite/procfs"
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)
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func procfsOpenRoot(proc *procfs.Handle, subpath string, flags int) (*os.File, error) {
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handle, err := proc.OpenRoot(subpath)
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if err != nil {
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return nil, err
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}
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defer handle.Close()
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return pathrs.Reopen(handle, flags)
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}
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// WriteSysctls sets the given sysctls to the requested values.
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func WriteSysctls(sysctls map[string]string) error {
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// We are going to write multiple sysctls, which require writing to an
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// unmasked procfs which is not going to be cached. To avoid creating a new
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// procfs instance for each one, just allocate one handle for all of them.
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proc, err := procfs.OpenUnsafeProcRoot()
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if err != nil {
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return err
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}
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defer proc.Close()
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for key, value := range sysctls {
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keyPath := strings.ReplaceAll(key, ".", "/")
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sysctlFile, err := procfsOpenRoot(proc, "sys/"+keyPath, unix.O_WRONLY|unix.O_TRUNC|unix.O_CLOEXEC)
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if err != nil {
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return fmt.Errorf("open sysctl %s file: %w", key, err)
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}
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defer sysctlFile.Close()
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_, err = sysctlFile.WriteString(value)
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if err != nil {
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return fmt.Errorf("failed to write sysctl %s = %q: %w", key, value, err)
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}
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}
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return nil
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}
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