[Devel] [PATCH v3 09/10] 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 |    1 +
 ipc/compat.c        |    3 +++
 ipc/msg.c           |   18 ++++++++++++++++++
 3 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/include/linux/msg.h b/include/linux/msg.h
index 07a5e1e..4e9ddf4 100644
--- a/include/linux/msg.h
+++ b/include/linux/msg.h
@@ -7,6 +7,7 @@
 #define MSG_STAT 11
 #define MSG_INFO 12
 #define MSG_SET  13
+#define MSG_SET_COPY  14
 
 /* msgrcv options */
 #define MSG_NOERROR     010000  /* no error if message is too big */
diff --git a/ipc/compat.c b/ipc/compat.c
index 6b07f5c..9e5acc7 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_COPY:
+#endif
 		err = sys_msgctl(first, second, uptr);
 		break;
 
diff --git a/ipc/msg.c b/ipc/msg.c
index 44ba0ce..c63b22e 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 copy_cnt;
+
+		if (!buf)
+			return -EFAULT;
+		if (get_user(copy_cnt, (unsigned int *)buf))
+			return -EFAULT;
+
+		msq = msg_lock(ns, msqid);
+		if (IS_ERR(msq))
+			return PTR_ERR(msq);
+		msq->q_copy_cnt = copy_cnt;
+		err = 0;
+		break;
+	}
+#endif
 	default:
 		return  -EINVAL;
 	}