mirror of
https://github.com/opencontainers/runc.git
synced 2026-07-10 21:53:57 +08:00
Daniel, Dao Quang Minh
7d423cb7a1
replace passing of pid and console path via environment variable with passing them with netlink message via an established pipe. this change requires us to set _LIBCONTAINER_INITTYPE and _LIBCONTAINER_INITPIPE as the env environment of the bootstrap process as we only send the bootstrap data for setns process right now. When init and setns bootstrap process are unified (i.e., init use nsexec instead of Go to clone new process), we can remove _LIBCONTAINER_INITTYPE. Note: - we read nlmsghdr first before reading the content so we can get the total length of the payload and allocate buffer properly instead of allocating one large buffer. - check read bytes vs the wanted number. It's an error if we failed to read the desired number of bytes from the pipe into the buffer. Signed-off-by: Daniel, Dao Quang Minh <dqminh89@gmail.com>
61 lines
1.3 KiB
Go
61 lines
1.3 KiB
Go
// +build linux
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package libcontainer
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import (
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"syscall"
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"github.com/vishvananda/netlink/nl"
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)
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// list of known message types we want to send to bootstrap program
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// The number is randomly chosen to not conflict with known netlink types
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const (
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InitMsg uint16 = 62000
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PidAttr uint16 = 27281
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ConsolePathAttr uint16 = 27282
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)
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type Int32msg struct {
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Type uint16
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Value uint32
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}
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// int32msg has the following representation
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// | nlattr len | nlattr type |
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// | uint32 value |
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func (msg *Int32msg) Serialize() []byte {
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buf := make([]byte, msg.Len())
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native := nl.NativeEndian()
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native.PutUint16(buf[0:2], uint16(msg.Len()))
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native.PutUint16(buf[2:4], msg.Type)
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native.PutUint32(buf[4:8], msg.Value)
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return buf
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}
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func (msg *Int32msg) Len() int {
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return syscall.NLA_HDRLEN + 4
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}
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// bytemsg has the following representation
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// | nlattr len | nlattr type |
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// | value | pad |
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type Bytemsg struct {
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Type uint16
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Value []byte
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}
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func (msg *Bytemsg) Serialize() []byte {
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l := msg.Len()
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buf := make([]byte, (l+syscall.NLA_ALIGNTO-1) & ^(syscall.NLA_ALIGNTO-1))
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native := nl.NativeEndian()
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native.PutUint16(buf[0:2], uint16(l))
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native.PutUint16(buf[2:4], msg.Type)
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copy(buf[4:], msg.Value)
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return buf
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}
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func (msg *Bytemsg) Len() int {
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return syscall.NLA_HDRLEN + len(msg.Value) + 1 // null-terminated
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}
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