Add abi definitions for sysv message queues.

Updates #135

pkg/abi/linux/BUILD

@@ -41,6 +41,7 @@ go_library(
         "linux.go",
         "membarrier.go",
         "mm.go",
+        "msgqueue.go",
         "netdevice.go",
         "netfilter.go",
         "netfilter_ipv6.go",

pkg/abi/linux/msgqueue.go

@@ -0,0 +1,108 @@
+// Copyright 2021 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package linux
+
+import (
+	"gvisor.dev/gvisor/pkg/marshal/primitive"
+)
+
+// Linux-specific control commands. Source: include/uapi/linux/msg.h
+const (
+	MSG_STAT     = 11
+	MSG_INFO     = 12
+	MSG_STAT_ANY = 13
+)
+
+// msgrcv(2) options. Source: include/uapi/linux/msg.h
+const (
+	MSG_NOERROR = 010000 // No error if message is too big.
+	MSG_EXCEPT  = 020000 // Receive any message except of specified type.
+	MSG_COPY    = 040000 // Copy (not remove) all queue messages.
+)
+
+// System-wide limits for message queues. Source: include/uapi/linux/msg.h
+const (
+	MSGMNI = 32000 // Maximum number of message queue identifiers.
+	MSGMAX = 8192  // Maximum size of message (bytes).
+	MSGMNB = 16384 // Default max size of a message queue.
+)
+
+// System-wide limits. Unused. Source: include/uapi/linux/msg.h
+const (
+	MSGPOOL = (MSGMNI * MSGMNB / 1024)
+	MSGTQL  = MSGMNB
+	MSGMAP  = MSGMNB
+	MSGSSZ  = 16
+
+	// MSGSEG is simplified due to the inexistance of a ternary operator.
+	MSGSEG = (MSGPOOL * 1024) / MSGSSZ
+)
+
+// MsqidDS is equivelant to struct msqid64_ds. Source:
+// include/uapi/asm-generic/shmbuf.h
+//
+// +marshal
+type MsqidDS struct {
+	MsgPerm   IPCPerm // IPC permissions.
+	MsgStime  TimeT   // Last msgsnd time.
+	MsgRtime  TimeT   // Last msgrcv time.
+	MsgCtime  TimeT   // Last change time.
+	MsgCbytes uint64  // Current number of bytes on the queue.
+	MsgQnum   uint64  // Number of messages in the queue.
+	MsgQbytes uint64  // Max number of bytes in the queue.
+	MsgLspid  int32   // PID of last msgsnd.
+	MsgLrpid  int32   // PID of last msgrcv.
+	unused4   uint64
+	unused5   uint64
+}
+
+// MsgBuf is equivelant to struct msgbuf. Source: include/uapi/linux/msg.h
+//
+// +marshal dynamic
+type MsgBuf struct {
+	Type primitive.Int64
+	Text primitive.ByteSlice
+}
+
+// SizeBytes implements marshal.Marshallable.SizeBytes.
+func (b *MsgBuf) SizeBytes() int {
+	return b.Type.SizeBytes() + b.Text.SizeBytes()
+}
+
+// MarshalBytes implements marshal.Marshallable.MarshalBytes.
+func (b *MsgBuf) MarshalBytes(dst []byte) {
+	b.Type.MarshalUnsafe(dst)
+	b.Text.MarshalBytes(dst[b.Type.SizeBytes():])
+}
+
+// UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes.
+func (b *MsgBuf) UnmarshalBytes(src []byte) {
+	b.Type.UnmarshalUnsafe(src)
+	b.Text.UnmarshalBytes(src[b.Type.SizeBytes():])
+}
+
+// MsgInfo is equivelant to struct msginfo. Source: include/uapi/linux/msg.h
+//
+// +marshal
+type MsgInfo struct {
+	MsgPool int32
+	MsgMap  int32
+	MsgMax  int32
+	MsgMnb  int32
+	MsgMni  int32
+	MsgSsz  int32
+	MsgTql  int32
+	MsgSeg  uint16 `marshal:"unaligned"`
+}