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https://github.com/opencontainers/runc.git
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lifubang
124 lines
2.9 KiB
Go
124 lines
2.9 KiB
Go
package libcontainer
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import (
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"io/fs"
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"strconv"
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"golang.org/x/sys/unix"
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)
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// mountError holds an error from a failed mount or unmount operation.
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type mountError struct {
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op string
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source string
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srcFD *int
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target string
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dstFD string
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flags uintptr
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data string
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err error
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}
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// Error provides a string error representation.
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func (e *mountError) Error() string {
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out := e.op + " "
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if e.source != "" {
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out += "src=" + e.source + ", "
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if e.srcFD != nil {
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out += "srcFD=" + strconv.Itoa(*e.srcFD) + ", "
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}
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}
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out += "dst=" + e.target
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if e.dstFD != "" {
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out += ", dstFD=" + e.dstFD
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}
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if e.flags != uintptr(0) {
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out += ", flags=0x" + strconv.FormatUint(uint64(e.flags), 16)
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}
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if e.data != "" {
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out += ", data=" + e.data
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}
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out += ": " + e.err.Error()
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return out
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}
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// Unwrap returns the underlying error.
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// This is a convention used by Go 1.13+ standard library.
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func (e *mountError) Unwrap() error {
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return e.err
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}
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// mount is a simple unix.Mount wrapper, returning an error with more context
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// in case it failed.
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func mount(source, target, fstype string, flags uintptr, data string) error {
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return mountViaFDs(source, nil, target, "", fstype, flags, data)
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}
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// mountViaFDs is a unix.Mount wrapper which uses srcFD instead of source,
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// and dstFD instead of target, unless those are empty.
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// If srcFD is different than nil, its path (i.e. "/proc/self/fd/NN") will be
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// constructed by this function.
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// dstFD argument, if non-empty, is expected to be in the form of a path to an
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// opened file descriptor on procfs (i.e. "/proc/self/fd/NN").
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//
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// If case an FD is used instead of a source or a target path, the
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// corresponding path is only used to add context to an error in case
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// the mount operation has failed.
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func mountViaFDs(source string, srcFD *int, target, dstFD, fstype string, flags uintptr, data string) error {
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src := source
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if srcFD != nil {
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src = "/proc/self/fd/" + strconv.Itoa(*srcFD)
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}
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dst := target
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if dstFD != "" {
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dst = dstFD
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}
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if err := unix.Mount(src, dst, fstype, flags, data); err != nil {
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return &mountError{
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op: "mount",
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source: source,
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srcFD: srcFD,
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target: target,
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dstFD: dstFD,
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flags: flags,
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data: data,
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err: err,
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}
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}
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return nil
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}
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// unmount is a simple unix.Unmount wrapper.
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func unmount(target string, flags int) error {
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err := unix.Unmount(target, flags)
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if err != nil {
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return &mountError{
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op: "unmount",
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target: target,
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flags: uintptr(flags),
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err: err,
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}
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}
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return nil
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}
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// syscallMode returns the syscall-specific mode bits from Go's portable mode bits.
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// Copy from https://cs.opensource.google/go/go/+/refs/tags/go1.20.7:src/os/file_posix.go;l=61-75
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func syscallMode(i fs.FileMode) (o uint32) {
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o |= uint32(i.Perm())
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if i&fs.ModeSetuid != 0 {
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o |= unix.S_ISUID
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}
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if i&fs.ModeSetgid != 0 {
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o |= unix.S_ISGID
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}
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if i&fs.ModeSticky != 0 {
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o |= unix.S_ISVTX
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}
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// No mapping for Go's ModeTemporary (plan9 only).
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return
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}
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