3 files changed, 101 insertions, 2 deletions

diff --git a/ipc/msg.c b/ipc/msg.c
index cefc24f46e3e..d20ffc7d3f24 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -769,6 +769,45 @@ static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
 	return msgsz;
 }
 
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static inline struct msg_msg *fill_copy(unsigned long copy_nr,
+					unsigned long msg_nr,
+					struct msg_msg *msg,
+					struct msg_msg *copy)
+{
+	if (copy_nr == msg_nr)
+		return copy_msg(msg, copy);
+	return NULL;
+}
+
+static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz,
+					   int msgflg, long *msgtyp,
+					   unsigned long *copy_number)
+{
+	struct msg_msg *copy;
+
+	*copy_number = *msgtyp;
+	*msgtyp = 0;
+	/*
+	 * Create dummy message to copy real message to.
+	 */
+	copy = load_msg(buf, bufsz);
+	if (!IS_ERR(copy))
+		copy->m_ts = bufsz;
+	return copy;
+}
+
+static inline void free_copy(int msgflg, struct msg_msg *copy)
+{
+	if (msgflg & MSG_COPY)
+		free_msg(copy);
+}
+#else
+#define free_copy(msgflg, copy)				do {} while (0)
+#define prepare_copy(buf, sz, msgflg, msgtyp, copy_nr)	ERR_PTR(-ENOSYS)
+#define fill_copy(copy_nr, msg_nr, msg, copy)		NULL
+#endif
+
 long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
 	       int msgflg,
 	       long (*msg_handler)(void __user *, struct msg_msg *, size_t))
@@ -777,19 +816,29 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
 	struct msg_msg *msg;
 	int mode;
 	struct ipc_namespace *ns;
+	struct msg_msg *copy;
+	unsigned long __maybe_unused copy_number;
 
 	if (msqid < 0 || (long) bufsz < 0)
 		return -EINVAL;
+	if (msgflg & MSG_COPY) {
+		copy = prepare_copy(buf, bufsz, msgflg, &msgtyp, &copy_number);
+		if (IS_ERR(copy))
+			return PTR_ERR(copy);
+	}
 	mode = convert_mode(&msgtyp, msgflg);
 	ns = current->nsproxy->ipc_ns;
 
 	msq = msg_lock_check(ns, msqid);
-	if (IS_ERR(msq))
+	if (IS_ERR(msq)) {
+		free_copy(msgflg, copy);
 		return PTR_ERR(msq);
+	}
 
 	for (;;) {
 		struct msg_receiver msr_d;
 		struct list_head *tmp;
+		long msg_counter = 0;
 
 		msg = ERR_PTR(-EACCES);
 		if (ipcperms(ns, &msq->q_perm, S_IRUGO))
@@ -809,8 +858,15 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
 				if (mode == SEARCH_LESSEQUAL &&
 						walk_msg->m_type != 1) {
 					msgtyp = walk_msg->m_type - 1;
+				} else if (msgflg & MSG_COPY) {
+					msg = fill_copy(copy_number,
+							msg_counter,
+							walk_msg, copy);
+					if (msg)
+						break;
 				} else
 					break;
+				msg_counter++;
 			}
 			tmp = tmp->next;
 		}
@@ -823,6 +879,8 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
 				msg = ERR_PTR(-E2BIG);
 				goto out_unlock;
 			}
+			if (msgflg & MSG_COPY)
+				goto out_unlock;
 			list_del(&msg->m_list);
 			msq->q_qnum--;
 			msq->q_rtime = get_seconds();
@@ -906,8 +964,10 @@ out_unlock:
 			break;
 		}
 	}
-	if (IS_ERR(msg))
+	if (IS_ERR(msg)) {
+		free_copy(msgflg, copy);
 		return PTR_ERR(msg);
+	}
 
 	bufsz = msg_handler(buf, msg, bufsz);
 	free_msg(msg);
diff --git a/ipc/msgutil.c b/ipc/msgutil.c
index 6471f1bdae96..7eecdad40efc 100644
--- a/ipc/msgutil.c
+++ b/ipc/msgutil.c
@@ -102,7 +102,45 @@ out_err:
 	free_msg(msg);
 	return ERR_PTR(err);
 }
+#ifdef CONFIG_CHECKPOINT_RESTORE
+struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
+{
+	struct msg_msgseg *dst_pseg, *src_pseg;
+	int len = src->m_ts;
+	int alen;
+
+	BUG_ON(dst == NULL);
+	if (src->m_ts > dst->m_ts)
+		return ERR_PTR(-EINVAL);
+
+	alen = len;
+	if (alen > DATALEN_MSG)
+		alen = DATALEN_MSG;
+
+	dst->next = NULL;
+	dst->security = NULL;
 
+	memcpy(dst + 1, src + 1, alen);
+
+	len -= alen;
+	dst_pseg = dst->next;
+	src_pseg = src->next;
+	while (len > 0) {
+		alen = len;
+		if (alen > DATALEN_SEG)
+			alen = DATALEN_SEG;
+		memcpy(dst_pseg + 1, src_pseg + 1, alen);
+		dst_pseg = dst_pseg->next;
+		len -= alen;
+		src_pseg = src_pseg->next;
+	}
+
+	dst->m_type = src->m_type;
+	dst->m_ts = src->m_ts;
+
+	return dst;
+}
+#endif
 int store_msg(void __user *dest, struct msg_msg *msg, int len)
 {
 	int alen;
diff --git a/ipc/util.h b/ipc/util.h
index a61e0ca2bffd..eeb79a1fbd83 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -140,6 +140,7 @@ int ipc_parse_version (int *cmd);
 
 extern void free_msg(struct msg_msg *msg);
 extern struct msg_msg *load_msg(const void __user *src, int len);
+extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
 extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
 
 extern void recompute_msgmni(struct ipc_namespace *);