Implement stubs for msgsnd(2) and msgrcv(2).

Add support for msgsnd and msgrcv and enable syscall tests.

Updates #135

5 files changed, 99 insertions, 51 deletions

diff --git a/pkg/sentry/kernel/msgqueue/msgqueue.go b/pkg/sentry/kernel/msgqueue/msgqueue.go
index 21025797d..28520b19a 100644
--- a/pkg/sentry/kernel/msgqueue/msgqueue.go
+++ b/pkg/sentry/kernel/msgqueue/msgqueue.go
@@ -386,6 +386,15 @@ func (q *Queue) pop(ctx context.Context, creds *auth.Credentials, mType int64, m
 	return msg, nil
 }
 
+// Copy copies a message from the queue without deleting it. See
+// msgrcv(MSG_COPY).
+func (q *Queue) Copy() (*Message, error) {
+	q.mu.Lock()
+	defer q.mu.Unlock()
+
+	return nil, linuxerr.ENOSYS
+}
+
 // msgOfType returns the first message with the specified type, nil if no
 // message is found. If except is true, the first message of a type not equal
 // to mType will be returned.
diff --git a/pkg/sentry/syscalls/linux/BUILD b/pkg/sentry/syscalls/linux/BUILD
index ccccce6a9..b5a371d9a 100644
--- a/pkg/sentry/syscalls/linux/BUILD
+++ b/pkg/sentry/syscalls/linux/BUILD
@@ -86,6 +86,7 @@ go_library(
         "//pkg/sentry/kernel/eventfd",
         "//pkg/sentry/kernel/fasync",
         "//pkg/sentry/kernel/ipc",
+        "//pkg/sentry/kernel/msgqueue",
         "//pkg/sentry/kernel/pipe",
         "//pkg/sentry/kernel/sched",
         "//pkg/sentry/kernel/shm",
diff --git a/pkg/sentry/syscalls/linux/linux64.go b/pkg/sentry/syscalls/linux/linux64.go
index 6f44d767b..6a5a30516 100644
--- a/pkg/sentry/syscalls/linux/linux64.go
+++ b/pkg/sentry/syscalls/linux/linux64.go
@@ -122,8 +122,8 @@ var AMD64 = &kernel.SyscallTable{
 		66:  syscalls.Supported("semctl", Semctl),
 		67:  syscalls.Supported("shmdt", Shmdt),
 		68:  syscalls.Supported("msgget", Msgget),
-		69:  syscalls.ErrorWithEvent("msgsnd", linuxerr.ENOSYS, "", []string{"gvisor.dev/issue/135"}), // TODO(b/29354921)
-		70:  syscalls.ErrorWithEvent("msgrcv", linuxerr.ENOSYS, "", []string{"gvisor.dev/issue/135"}), // TODO(b/29354921)
+		69:  syscalls.Supported("msgsnd", Msgsnd),
+		70:  syscalls.PartiallySupported("msgrcv", Msgrcv, "Doesn't support MSG_COPY option.", []string{"gvisor.dev/issue/135"}),
 		71:  syscalls.PartiallySupported("msgctl", Msgctl, "Only supports IPC_RMID option.", []string{"gvisor.dev/issue/135"}),
 		72:  syscalls.PartiallySupported("fcntl", Fcntl, "Not all options are supported.", nil),
 		73:  syscalls.PartiallySupported("flock", Flock, "Locks are held within the sandbox only.", nil),
@@ -618,8 +618,8 @@ var ARM64 = &kernel.SyscallTable{
 		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"}),
-		188: syscalls.ErrorWithEvent("msgrcv", linuxerr.ENOSYS, "", []string{"gvisor.dev/issue/135"}), // TODO(b/29354921)
-		189: syscalls.ErrorWithEvent("msgsnd", linuxerr.ENOSYS, "", []string{"gvisor.dev/issue/135"}), // TODO(b/29354921)
+		188: syscalls.PartiallySupported("msgrcv", Msgrcv, "Doesn't support MSG_COPY option.", []string{"gvisor.dev/issue/135"}),
+		189: syscalls.Supported("msgsnd", Msgsnd),
 		190: syscalls.Supported("semget", Semget),
 		191: syscalls.Supported("semctl", Semctl),
 		192: syscalls.Supported("semtimedop", Semtimedop),
diff --git a/pkg/sentry/syscalls/linux/sys_msgqueue.go b/pkg/sentry/syscalls/linux/sys_msgqueue.go
index 3476e218d..d61777d02 100644
--- a/pkg/sentry/syscalls/linux/sys_msgqueue.go
+++ b/pkg/sentry/syscalls/linux/sys_msgqueue.go
@@ -17,10 +17,12 @@ package linux
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/errors/linuxerr"
+	"gvisor.dev/gvisor/pkg/marshal/primitive"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/ipc"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/msgqueue"
 )
 
 // Msgget implements msgget(2).
@@ -41,6 +43,86 @@ func Msgget(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal
 	return uintptr(queue.ID()), nil, nil
 }
 
+// Msgsnd implements msgsnd(2).
+func Msgsnd(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	id := ipc.ID(args[0].Int())
+	msgAddr := args[1].Pointer()
+	size := args[2].Int64()
+	flag := args[3].Int()
+
+	if size < 0 || size > linux.MSGMAX {
+		return 0, nil, linuxerr.EINVAL
+	}
+
+	wait := flag&linux.IPC_NOWAIT != linux.IPC_NOWAIT
+	pid := int32(t.ThreadGroup().ID())
+
+	buf := linux.MsgBuf{
+		Text: make([]byte, size),
+	}
+	if _, err := buf.CopyIn(t, msgAddr); err != nil {
+		return 0, nil, err
+	}
+
+	queue, err := t.IPCNamespace().MsgqueueRegistry().FindByID(id)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	msg := msgqueue.Message{
+		Type: int64(buf.Type),
+		Text: buf.Text,
+		Size: uint64(size),
+	}
+	return 0, nil, queue.Send(t, msg, t, wait, pid)
+}
+
+// Msgrcv implements msgrcv(2).
+func Msgrcv(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	id := ipc.ID(args[0].Int())
+	msgAddr := args[1].Pointer()
+	size := args[2].Int64()
+	mType := args[3].Int64()
+	flag := args[4].Int()
+
+	wait := flag&linux.IPC_NOWAIT != linux.IPC_NOWAIT
+	except := flag&linux.MSG_EXCEPT == linux.MSG_EXCEPT
+	truncate := flag&linux.MSG_NOERROR == linux.MSG_NOERROR
+
+	msgCopy := flag&linux.MSG_COPY == linux.MSG_COPY
+
+	msg, err := receive(t, id, mType, size, msgCopy, wait, truncate, except)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	buf := linux.MsgBuf{
+		Type: primitive.Int64(msg.Type),
+		Text: msg.Text,
+	}
+	if _, err := buf.CopyOut(t, msgAddr); err != nil {
+		return 0, nil, err
+	}
+	return uintptr(msg.Size), nil, nil
+}
+
+// receive returns a message from the queue with the given ID. If msgCopy is
+// true, a message is copied from the queue without being removed. Otherwise,
+// a message is removed from the queue and returned.
+func receive(t *kernel.Task, id ipc.ID, mType int64, maxSize int64, msgCopy, wait, truncate, except bool) (*msgqueue.Message, error) {
+	pid := int32(t.ThreadGroup().ID())
+
+	queue, err := t.IPCNamespace().MsgqueueRegistry().FindByID(id)
+	if err != nil {
+		return nil, err
+	}
+
+	if msgCopy {
+		return queue.Copy()
+	}
+	return queue.Receive(t, t, mType, maxSize, wait, truncate, except, pid)
+}
+
 // Msgctl implements msgctl(2).
 func Msgctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
 	id := ipc.ID(args[0].Int())
diff --git a/test/syscalls/linux/msgqueue.cc b/test/syscalls/linux/msgqueue.cc
index 95eeb2ef9..28dbd6056 100644
--- a/test/syscalls/linux/msgqueue.cc
+++ b/test/syscalls/linux/msgqueue.cc
@@ -26,11 +26,6 @@ namespace gvisor {
 namespace testing {
 namespace {
 
-// run is a temporary variable to easily enable/disable running tests. This
-// variable should be removed along with SKIP_IF when the tested functionality
-// is enabled.
-constexpr bool run = false;
-
 constexpr int msgMax = 8192;   // Max size for message in bytes.
 constexpr int msgMni = 32000;  // Max number of identifiers.
 constexpr int msgMnb = 16384;  // Default max size of message queue in bytes.
@@ -115,8 +110,6 @@ TEST(MsgqueueTest, MsgGetIpcPrivate) {
 
 // Test simple msgsnd and msgrcv.
 TEST(MsgqueueTest, MsgOpSimple) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -133,8 +126,6 @@ TEST(MsgqueueTest, MsgOpSimple) {
 
 // Test msgsnd and msgrcv of an empty message.
 TEST(MsgqueueTest, MsgOpEmpty) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -148,8 +139,6 @@ TEST(MsgqueueTest, MsgOpEmpty) {
 
 // Test truncation of message with MSG_NOERROR flag.
 TEST(MsgqueueTest, MsgOpTruncate) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -165,8 +154,6 @@ TEST(MsgqueueTest, MsgOpTruncate) {
 
 // Test msgsnd and msgrcv using invalid arguments.
 TEST(MsgqueueTest, MsgOpInvalidArgs) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -185,12 +172,10 @@ TEST(MsgqueueTest, MsgOpInvalidArgs) {
 
 // Test non-blocking msgrcv with an empty queue.
 TEST(MsgqueueTest, MsgOpNoMsg) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
-  msgbuf rcv{1, ""};
+  msgbuf rcv;
   EXPECT_THAT(msgrcv(queue.get(), &rcv, sizeof(rcv.mtext) + 1, 0, IPC_NOWAIT),
               SyscallFailsWithErrno(ENOMSG));
 }
@@ -198,8 +183,6 @@ TEST(MsgqueueTest, MsgOpNoMsg) {
 // Test non-blocking msgrcv with a non-empty queue, but no messages of wanted
 // type.
 TEST(MsgqueueTest, MsgOpNoMsgType) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -213,8 +196,6 @@ TEST(MsgqueueTest, MsgOpNoMsgType) {
 
 // Test msgrcv with a larger size message than wanted, and truncation disabled.
 TEST(MsgqueueTest, MsgOpTooBig) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -228,8 +209,6 @@ TEST(MsgqueueTest, MsgOpTooBig) {
 
 // Test receiving messages based on type.
 TEST(MsgqueueTest, MsgRcvType) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -257,8 +236,6 @@ TEST(MsgqueueTest, MsgRcvType) {
 
 // Test using MSG_EXCEPT to receive a different-type message.
 TEST(MsgqueueTest, MsgExcept) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -285,8 +262,6 @@ TEST(MsgqueueTest, MsgExcept) {
 
 // Test msgrcv with a negative type.
 TEST(MsgqueueTest, MsgRcvTypeNegative) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -309,8 +284,6 @@ TEST(MsgqueueTest, MsgRcvTypeNegative) {
 
 // Test permission-related failure scenarios.
 TEST(MsgqueueTest, MsgOpPermissions) {
-  SKIP_IF(!run);
-
   AutoCapability cap(CAP_IPC_OWNER, false);
 
   Queue queue(msgget(IPC_PRIVATE, 0000));
@@ -326,8 +299,6 @@ TEST(MsgqueueTest, MsgOpPermissions) {
 
 // Test limits for messages and queues.
 TEST(MsgqueueTest, MsgOpLimits) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -376,8 +347,6 @@ bool MsgCopySupported() {
 
 // Test usage of MSG_COPY for msgrcv.
 TEST(MsgqueueTest, MsgCopy) {
-  SKIP_IF(!run);
-
   SKIP_IF(!MsgCopySupported());
 
   Queue queue(msgget(IPC_PRIVATE, 0600));
@@ -419,8 +388,6 @@ TEST(MsgqueueTest, MsgCopy) {
 
 // Test msgrcv (most probably) blocking on an empty queue.
 TEST(MsgqueueTest, MsgRcvBlocking) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -449,8 +416,6 @@ TEST(MsgqueueTest, MsgRcvBlocking) {
 
 // Test msgrcv (most probably) waiting for a specific-type message.
 TEST(MsgqueueTest, MsgRcvTypeBlocking) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -487,8 +452,6 @@ TEST(MsgqueueTest, MsgRcvTypeBlocking) {
 
 // Test msgsnd (most probably) blocking on a full queue.
 TEST(MsgqueueTest, MsgSndBlocking) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -508,8 +471,7 @@ TEST(MsgqueueTest, MsgSndBlocking) {
   if (child_pid == 0) {
     // Fill the queue.
     for (size_t i = 0; i < msgCount; i++) {
-      EXPECT_THAT(msgsnd(queue.get(), &buf, sizeof(buf.mtext), 0),
-                  SyscallSucceeds());
+      TEST_PCHECK(msgsnd(queue.get(), &buf, sizeof(buf.mtext), 0) == 0);
     }
 
     // Next msgsnd should block.
@@ -531,7 +493,7 @@ TEST(MsgqueueTest, MsgSndBlocking) {
   // Delay a bit more for the blocking msgsnd.
   absl::SleepFor(absl::Milliseconds(100));
 
-  EXPECT_THAT(msgrcv(queue.get(), &rcv, sizeof(buf.mtext) + 1, 0, 0),
+  EXPECT_THAT(msgrcv(queue.get(), &rcv, sizeof(buf.mtext), 0, 0),
               SyscallSucceedsWithValue(sizeof(buf.mtext)));
 
   int status;
@@ -542,8 +504,6 @@ TEST(MsgqueueTest, MsgSndBlocking) {
 
 // Test removing a queue while a blocking msgsnd is executing.
 TEST(MsgqueueTest, MsgSndRmWhileBlocking) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -592,8 +552,6 @@ TEST(MsgqueueTest, MsgSndRmWhileBlocking) {
 
 // Test removing a queue while a blocking msgrcv is executing.
 TEST(MsgqueueTest, MsgRcvRmWhileBlocking) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());
 
@@ -620,8 +578,6 @@ TEST(MsgqueueTest, MsgRcvRmWhileBlocking) {
 
 // Test a collection of msgsnd/msgrcv operations in different processes.
 TEST(MsgqueueTest, MsgOpGeneral) {
-  SKIP_IF(!run);
-
   Queue queue(msgget(IPC_PRIVATE, 0600));
   ASSERT_THAT(queue.get(), SyscallSucceeds());