The namespace is restored by creating each 'msq' object read from
the checkpoint image.
Message of a specific queue are first read and chained together on
a temporary list, and once done are attached atomically as a whole
to the newly created message queue ('msq').
Signed-off-by: Oren Laadan <[email protected]>
---
ipc/checkpoint.c | 4 +-
ipc/checkpoint_msg.c | 196 ++++++++++++++++++++++++++++++++++++++++++++++++++
ipc/util.h | 1 +
3 files changed, 199 insertions(+), 2 deletions(-)
diff --git a/ipc/checkpoint.c b/ipc/checkpoint.c
index 5f63300..dfd3286 100644
--- a/ipc/checkpoint.c
+++ b/ipc/checkpoint.c
@@ -211,11 +211,11 @@ static int do_restore_ipc_ns(struct ckpt_ctx *ctx)
ret = restore_ipc_any(ctx, IPC_SHM_IDS,
CKPT_HDR_IPC_SHM, restore_ipc_shm);
-#if 0 /* NEXT FEW PATCHES */
if (ret < 0)
goto out;
- ret = ckpt_read_ipc_any(ctx, IPC_MSG_IDS,
+ ret = restore_ipc_any(ctx, IPC_MSG_IDS,
CKPT_HDR_IPC_MSG, restore_ipc_msg);
+#if 0 /* NEXT FEW PATCHES */
if (ret < 0)
goto out;
ret = restore_ipc_any(ctx, IPC_SEM_IDS,
diff --git a/ipc/checkpoint_msg.c b/ipc/checkpoint_msg.c
index f0b0921..a4099e5 100644
--- a/ipc/checkpoint_msg.c
+++ b/ipc/checkpoint_msg.c
@@ -162,3 +162,199 @@ int checkpoint_ipc_msg(int id, void *p, void *data)
ckpt_hdr_put(ctx, h);
return ret;
}
+
+
+/************************************************************************
+ * ipc restart
+ */
+
+static int load_ipc_msg_hdr(struct ckpt_ctx *ctx,
+ struct ckpt_hdr_ipc_msg *h,
+ struct msg_queue *msq)
+{
+ int ret = 0;
+
+ ret = restore_load_ipc_perms(&h->perms, &msq->q_perm);
+ if (ret < 0)
+ return ret;
+
+ ckpt_debug("msq: lspid %d lrpid %d qnum %lld qbytes %lld\n",
+ h->q_lspid, h->q_lrpid, h->q_qnum, h->q_qbytes);
+
+ if (h->q_lspid < 0 || h->q_lrpid < 0)
+ return -EINVAL;
+
+ msq->q_stime = h->q_stime;
+ msq->q_rtime = h->q_rtime;
+ msq->q_ctime = h->q_ctime;
+ msq->q_lspid = h->q_lspid;
+ msq->q_lrpid = h->q_lrpid;
+
+ return 0;
+}
+
+static struct msg_msg *restore_msg_contents_one(struct ckpt_ctx *ctx, int
*clen)
+{
+ struct ckpt_hdr_ipc_msg_msg *h;
+ struct msg_msg *msg = NULL;
+ struct msg_msgseg *seg, **pseg;
+ int total, len;
+ int ret;
+
+ h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_IPC_MSG_MSG);
+ if (IS_ERR(h))
+ return (struct msg_msg *) h;
+
+ ret = -EINVAL;
+ if (h->m_type < 1)
+ goto out;
+ if (h->m_ts > current->nsproxy->ipc_ns->msg_ctlmax)
+ goto out;
+
+ total = h->m_ts;
+ len = min(total, (int) DATALEN_MSG);
+ msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
+ if (!msg) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ msg->next = NULL;
+ pseg = &msg->next;
+
+ ret = _ckpt_read_buffer(ctx, (msg + 1), len);
+ if (ret < 0)
+ goto out;
+
+ total -= len;
+ while (total) {
+ len = min(total, (int) DATALEN_SEG);
+ seg = kmalloc(sizeof(*seg) + len, GFP_KERNEL);
+ if (!seg) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ seg->next = NULL;
+ *pseg = seg;
+ pseg = &seg->next;
+
+ ret = _ckpt_read_buffer(ctx, (seg + 1), len);
+ if (ret < 0)
+ goto out;
+ total -= len;
+ }
+
+ msg->m_type = h->m_type;
+ msg->m_ts = h->m_ts;
+ *clen = h->m_ts;
+ out:
+ if (ret < 0 && msg) {
+ free_msg(msg);
+ msg = ERR_PTR(ret);
+ }
+ ckpt_hdr_put(ctx, h);
+ return msg;
+}
+
+static inline void free_msg_list(struct list_head *queue)
+{
+ struct msg_msg *msg, *tmp;
+
+ list_for_each_entry_safe(msg, tmp, queue, m_list)
+ free_msg(msg);
+}
+
+static int restore_msg_contents(struct ckpt_ctx *ctx, struct list_head *queue,
+ unsigned long qnum, unsigned long *cbytes)
+{
+ struct msg_msg *msg;
+ int clen = 0;
+ int ret = 0;
+
+ INIT_LIST_HEAD(queue);
+
+ *cbytes = 0;
+ while (qnum--) {
+ msg = restore_msg_contents_one(ctx, &clen);
+ if (IS_ERR(msg))
+ goto fail;
+ list_add_tail(&msg->m_list, queue);
+ *cbytes += clen;
+ }
+ return 0;
+ fail:
+ ret = PTR_ERR(msg);
+ free_msg_list(queue);
+ return ret;
+}
+
+int restore_ipc_msg(struct ckpt_ctx *ctx)
+{
+ struct ckpt_hdr_ipc_msg *h;
+ struct kern_ipc_perm *perms;
+ struct msg_queue *msq;
+ struct ipc_ids *msg_ids = ¤t->nsproxy->ipc_ns->ids[IPC_MSG_IDS];
+ struct list_head messages;
+ unsigned long cbytes;
+ int msgflag;
+ int ret;
+
+ INIT_LIST_HEAD(&messages);
+
+ h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_IPC_MSG);
+ if (IS_ERR(h))
+ return PTR_ERR(h);
+
+ ret = -EINVAL;
+ if (h->perms.id < 0)
+ goto out;
+
+ /* read queued messages into temporary queue */
+ ret = restore_msg_contents(ctx, &messages, h->q_qnum, &cbytes);
+ if (ret < 0)
+ goto out;
+
+ ret = -EINVAL;
+ if (h->q_cbytes != cbytes)
+ goto out;
+
+ /* restore the message queue */
+ msgflag = h->perms.mode | IPC_CREAT | IPC_EXCL;
+ ckpt_debug("msg: do_msgget key %d flag %#x id %d\n",
+ h->perms.key, msgflag, h->perms.id);
+ ret = do_msgget(h->perms.key, msgflag, h->perms.id);
+ ckpt_debug("msg: do_msgget ret %d\n", ret);
+ if (ret < 0)
+ goto out;
+
+ down_write(&msg_ids->rw_mutex);
+
+ /* we are the sole owners/users of this ipc_ns, it can't go away */
+ perms = ipc_lock(msg_ids, h->perms.id);
+ BUG_ON(IS_ERR(perms)); /* ipc_ns is private to us */
+
+ msq = container_of(perms, struct msg_queue, q_perm);
+ BUG_ON(!list_empty(&msq->q_messages)); /* ipc_ns is private to us */
+
+ /* attach queued messages we read before */
+ list_splice_init(&messages, &msq->q_messages);
+
+ /* adjust msq and namespace statistics */
+ atomic_add(h->q_cbytes, ¤t->nsproxy->ipc_ns->msg_bytes);
+ atomic_add(h->q_qnum, ¤t->nsproxy->ipc_ns->msg_hdrs);
+ msq->q_cbytes = h->q_cbytes;
+ msq->q_qbytes = h->q_qbytes;
+ msq->q_qnum = h->q_qnum;
+
+ ret = load_ipc_msg_hdr(ctx, h, msq);
+ ipc_unlock(perms);
+
+ if (ret < 0) {
+ ckpt_debug("msq: need to remove (%d)\n", ret);
+ freeque(current->nsproxy->ipc_ns, perms);
+ }
+ up_write(&msg_ids->rw_mutex);
+ out:
+ free_msg_list(&messages); /* no-op if all ok, else cleanup msgs */
+ ckpt_hdr_put(ctx, h);
+ return ret;
+}
diff --git a/ipc/util.h b/ipc/util.h
index ab83ca3..1e464fd 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -198,6 +198,7 @@ extern int checkpoint_ipc_shm(int id, void *p, void *data);
extern int restore_ipc_shm(struct ckpt_ctx *ctx);
extern int checkpoint_ipc_msg(int id, void *p, void *data);
+extern int restore_ipc_msg(struct ckpt_ctx *ctx);
#endif
#endif
--
1.5.4.3
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