[CRIU] [PATCH 2/2] ipc: add new MSG_SET_COPY command for sys_msgctl() call

[Stanislav Kinsbursky]

New MSG_SET_COPY allows to set specified queue copy counter to passed value.
Passed "struct msqid_ds *buf" interpreted as pointer to unsigned int in this
case.
---
 include/linux/msg.h |    4 ++++
 ipc/compat.c        |    3 +++
 ipc/msg.c           |   18 ++++++++++++++++++
 3 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/include/linux/msg.h b/include/linux/msg.h
index de739d1..b63d6a4 100644
--- a/include/linux/msg.h
+++ b/include/linux/msg.h
@@ -8,6 +8,10 @@
 #define MSG_INFO 12
 #define MSG_SET  13
 
+#ifdef CONFIG_CHECKPOINT_RESTORE
+#define MSG_SET_COPY  14
+#endif
+
 /* msgrcv options */
 #define MSG_NOERROR     010000  /* no error if message is too big */
 #define MSG_EXCEPT      020000  /* recv any msg except of specified type.*/
diff --git a/ipc/compat.c b/ipc/compat.c
index 6b07f5c..0d211f7 100644
--- a/ipc/compat.c
+++ b/ipc/compat.c
@@ -481,6 +481,9 @@ long compat_sys_msgctl(int first, int second, void __user *uptr)
 	case IPC_INFO:
 	case IPC_RMID:
 	case MSG_INFO:
+#ifdef CONFIG_CHECKPOINT_RESTORE
+	case MSG_SET_PEEK:
+#endif
 		err = sys_msgctl(first, second, uptr);
 		break;
 
diff --git a/ipc/msg.c b/ipc/msg.c
index d4ca06f..44a2153 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -579,6 +579,24 @@ SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
 	case MSG_SET:
 		err = msgctl_down(ns, msqid, cmd, buf, version);
 		return err;
+#ifdef CONFIG_CHECKPOINT_RESTORE
+	case MSG_SET_COPY:
+	{
+		int peek_cnt;
+
+		if (!buf)
+			return -EFAULT;
+		if (get_user(peek_cnt, (unsigned int *)buf))
+			return -EFAULT;
+
+		msq = msg_lock(ns, msqid);
+		if (IS_ERR(msq))
+			return PTR_ERR(msq);
+		msq->q_peek_cnt = peek_cnt;
+		err = 0;
+		break;
+	}
+#endif
 	default:
 		return  -EINVAL;
 	}