forked from opencontainers/runc
/
message_linux.go
97 lines (85 loc) · 2.33 KB
/
message_linux.go
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package libcontainer
import (
"fmt"
"math"
"github.com/vishvananda/netlink/nl"
"golang.org/x/sys/unix"
)
// list of known message types we want to send to bootstrap program
// The number is randomly chosen to not conflict with known netlink types
const (
InitMsg uint16 = 62000
CloneFlagsAttr uint16 = 27281
NsPathsAttr uint16 = 27282
UidmapAttr uint16 = 27283
GidmapAttr uint16 = 27284
SetgroupAttr uint16 = 27285
OomScoreAdjAttr uint16 = 27286
RootlessEUIDAttr uint16 = 27287
UidmapPathAttr uint16 = 27288
GidmapPathAttr uint16 = 27289
MountSourcesAttr uint16 = 27290
)
type Int32msg struct {
Type uint16
Value uint32
}
// Serialize serializes the message.
// Int32msg has the following representation
// | nlattr len | nlattr type |
// | uint32 value |
func (msg *Int32msg) Serialize() []byte {
buf := make([]byte, msg.Len())
native := nl.NativeEndian()
native.PutUint16(buf[0:2], uint16(msg.Len()))
native.PutUint16(buf[2:4], msg.Type)
native.PutUint32(buf[4:8], msg.Value)
return buf
}
func (msg *Int32msg) Len() int {
return unix.NLA_HDRLEN + 4
}
// Bytemsg has the following representation
// | nlattr len | nlattr type |
// | value | pad |
type Bytemsg struct {
Type uint16
Value []byte
}
func (msg *Bytemsg) Serialize() []byte {
l := msg.Len()
if l > math.MaxUint16 {
// We cannot return nil nor an error here, so we panic with
// a specific type instead, which is handled via recover in
// bootstrapData.
panic(netlinkError{fmt.Errorf("netlink: cannot serialize bytemsg of length %d (larger than UINT16_MAX)", l)})
}
buf := make([]byte, (l+unix.NLA_ALIGNTO-1) & ^(unix.NLA_ALIGNTO-1))
native := nl.NativeEndian()
native.PutUint16(buf[0:2], uint16(l))
native.PutUint16(buf[2:4], msg.Type)
copy(buf[4:], msg.Value)
return buf
}
func (msg *Bytemsg) Len() int {
return unix.NLA_HDRLEN + len(msg.Value) + 1 // null-terminated
}
type Boolmsg struct {
Type uint16
Value bool
}
func (msg *Boolmsg) Serialize() []byte {
buf := make([]byte, msg.Len())
native := nl.NativeEndian()
native.PutUint16(buf[0:2], uint16(msg.Len()))
native.PutUint16(buf[2:4], msg.Type)
if msg.Value {
native.PutUint32(buf[4:8], uint32(1))
} else {
native.PutUint32(buf[4:8], uint32(0))
}
return buf
}
func (msg *Boolmsg) Len() int {
return unix.NLA_HDRLEN + 4 // alignment
}