Implement stub for msgctl(2).

Add support for msgctl and enable tests.

Fixes #135

pkg/sentry/syscalls/linux/linux64.go

@@ -124,7 +124,7 @@ var AMD64 = &kernel.SyscallTable{
 		68:  syscalls.Supported("msgget", Msgget),
 		69:  syscalls.Supported("msgsnd", Msgsnd),
 		70:  syscalls.Supported("msgrcv", Msgrcv),
-		71:  syscalls.PartiallySupported("msgctl", Msgctl, "Only supports IPC_RMID option.", []string{"gvisor.dev/issue/135"}),
+		71:  syscalls.Supported("msgctl", Msgctl),
 		72:  syscalls.PartiallySupported("fcntl", Fcntl, "Not all options are supported.", nil),
 		73:  syscalls.PartiallySupported("flock", Flock, "Locks are held within the sandbox only.", nil),
 		74:  syscalls.PartiallySupported("fsync", Fsync, "Full data flush is not guaranteed at this time.", nil),
@@ -617,7 +617,7 @@ var ARM64 = &kernel.SyscallTable{
 		184: syscalls.ErrorWithEvent("mq_notify", syserror.ENOSYS, "", []string{"gvisor.dev/issue/136"}),       // TODO(b/29354921)
 		185: syscalls.ErrorWithEvent("mq_getsetattr", syserror.ENOSYS, "", []string{"gvisor.dev/issue/136"}),   // TODO(b/29354921)
 		186: syscalls.Supported("msgget", Msgget),
-		187: syscalls.PartiallySupported("msgctl", Msgctl, "Only supports IPC_RMID option.", []string{"gvisor.dev/issue/135"}),
+		187: syscalls.Supported("msgctl", Msgctl),
 		188: syscalls.Supported("msgrcv", Msgrcv),
 		189: syscalls.Supported("msgsnd", Msgsnd),
 		190: syscalls.Supported("semget", Semget),

pkg/sentry/syscalls/linux/sys_msgqueue.go

@@ -130,12 +130,63 @@ func receive(t *kernel.Task, id ipc.ID, mType int64, maxSize int64, msgCopy, wai
 func Msgctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
 	id := ipc.ID(args[0].Int())
 	cmd := args[1].Int()
+	buf := args[2].Pointer()
 
 	creds := auth.CredentialsFromContext(t)
 
+	r := t.IPCNamespace().MsgqueueRegistry()
+
 	switch cmd {
+	case linux.IPC_INFO:
+		info := r.IPCInfo(t)
+		_, err := info.CopyOut(t, buf)
+		return 0, nil, err
+	case linux.MSG_INFO:
+		msgInfo := r.MsgInfo(t)
+		_, err := msgInfo.CopyOut(t, buf)
+		return 0, nil, err
 	case linux.IPC_RMID:
-		return 0, nil, t.IPCNamespace().MsgqueueRegistry().Remove(id, creds)
+		return 0, nil, r.Remove(id, creds)
+	}
+
+	// Remaining commands use a queue.
+	queue, err := r.FindByID(id)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	switch cmd {
+	case linux.MSG_STAT:
+		// Technically, we should be treating id as "an index into the kernel's
+		// internal array that maintains information about all shared memory
+		// segments on the system". Since we don't track segments in an array,
+		// we'll just pretend the msqid is the index and do the same thing as
+		// IPC_STAT. Linux also uses the index as the msqid.
+		fallthrough
+	case linux.IPC_STAT:
+		stat, err := queue.Stat(t)
+		if err != nil {
+			return 0, nil, err
+		}
+		_, err = stat.CopyOut(t, buf)
+		return 0, nil, err
+
+	case linux.MSG_STAT_ANY:
+		stat, err := queue.StatAny(t)
+		if err != nil {
+			return 0, nil, err
+		}
+		_, err = stat.CopyOut(t, buf)
+		return 0, nil, err
+
+	case linux.IPC_SET:
+		var ds linux.MsqidDS
+		if _, err := ds.CopyIn(t, buf); err != nil {
+			return 0, nil, linuxerr.EINVAL
+		}
+		err := queue.Set(t, &ds)
+		return 0, nil, err
+
 	default:
 		return 0, nil, linuxerr.EINVAL
 	}

test/syscalls/linux/msgqueue.cc

@@ -662,8 +662,6 @@ TEST(MsgqueueTest, MsgOpGeneral) {
 
 // Test msgctl with IPC_STAT option.
 TEST(MsgqueueTest, MsgCtlIpcStat) {
-  GTEST_SKIP();
-
   auto start = absl::Now();
 
   Queue queue(msgget(IPC_PRIVATE, 0600));
@@ -734,8 +732,6 @@ TEST(MsgqueueTest, MsgCtlIpcStat) {
 
 // Test msgctl with IPC_STAT option on a write-only queue.
 TEST(MsgqueueTest, MsgCtlIpcStatWriteOnly) {
-  GTEST_SKIP();
-
   // Drop CAP_IPC_OWNER which allows us to bypass permissions.
   AutoCapability cap(CAP_IPC_OWNER, false);
 
@@ -749,8 +745,6 @@ TEST(MsgqueueTest, MsgCtlIpcStatWriteOnly) {
 
 // Test msgctl with IPC_SET option.
 TEST(MsgqueueTest, MsgCtlIpcSet) {
-  GTEST_SKIP();
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -767,8 +761,6 @@ TEST(MsgqueueTest, MsgCtlIpcSet) {
 
 // Test increasing msg_qbytes beyond limit with IPC_SET.
 TEST(MsgqueueTest, MsgCtlIpcSetMaxBytes) {
-  GTEST_SKIP();
-
   // Drop CAP_SYS_RESOURCE which allows us to increase msg_qbytes beyond the
   // system parameter MSGMNB.
   AutoCapability cap(CAP_SYS_RESOURCE, false);
@@ -792,8 +784,6 @@ TEST(MsgqueueTest, MsgCtlIpcSetMaxBytes) {
 
 // Test msgctl with IPC_INFO option.
 TEST(MsgqueueTest, MsgCtlIpcInfo) {
-  GTEST_SKIP();
-
   struct msginfo info;
   ASSERT_THAT(msgctl(0, IPC_INFO, reinterpret_cast<struct msqid_ds*>(&info)),
               SyscallSucceeds());
@@ -809,8 +799,6 @@ TEST(MsgqueueTest, MsgCtlIpcInfo) {
 
 // Test msgctl with MSG_INFO option.
 TEST(MsgqueueTest, MsgCtlMsgInfo) {
-  GTEST_SKIP();
-
   struct msginfo info;
   ASSERT_THAT(msgctl(0, MSG_INFO, reinterpret_cast<struct msqid_ds*>(&info)),
               SyscallSucceeds());