#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
-#define msg_unlock(msq) ipc_unlock(&(msq)->q_perm)
-
static void freeque(struct ipc_namespace *, struct kern_ipc_perm *);
static int newque(struct ipc_namespace *, struct ipc_params *);
#ifdef CONFIG_PROC_FS
IPC_MSG_IDS, sysvipc_msg_proc_show);
}
-/*
- * msg_lock_(check_) routines are called in the paths where the rw_mutex
- * is not held.
- */
-static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id)
-{
- struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id);
-
- if (IS_ERR(ipcp))
- return (struct msg_queue *)ipcp;
-
- return container_of(ipcp, struct msg_queue, q_perm);
-}
-
-static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns,
- int id)
-{
- struct kern_ipc_perm *ipcp = ipc_lock_check(&msg_ids(ns), id);
-
- if (IS_ERR(ipcp))
- return (struct msg_queue *)ipcp;
-
- return container_of(ipcp, struct msg_queue, q_perm);
-}
-
static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
{
struct kern_ipc_perm *ipcp = ipc_obtain_object(&msg_ids(ns), id);
ipc_rmid(&msg_ids(ns), &s->q_perm);
}
+static void msg_rcu_free(struct rcu_head *head)
+{
+ struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
+ struct msg_queue *msq = ipc_rcu_to_struct(p);
+
+ security_msg_queue_free(msq);
+ ipc_rcu_free(head);
+}
+
/**
* newque - Create a new msg queue
* @ns: namespace
* @params: ptr to the structure that contains the key and msgflg
*
- * Called with msg_ids.rw_mutex held (writer)
+ * Called with msg_ids.rwsem held (writer)
*/
static int newque(struct ipc_namespace *ns, struct ipc_params *params)
{
msq->q_perm.security = NULL;
retval = security_msg_queue_alloc(msq);
if (retval) {
- ipc_rcu_putref(msq);
+ ipc_rcu_putref(msq, ipc_rcu_free);
return retval;
}
- /* ipc_addid() locks msq upon success. */
- id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
- if (id < 0) {
- security_msg_queue_free(msq);
- ipc_rcu_putref(msq);
- return id;
- }
-
msq->q_stime = msq->q_rtime = 0;
msq->q_ctime = get_seconds();
msq->q_cbytes = msq->q_qnum = 0;
INIT_LIST_HEAD(&msq->q_receivers);
INIT_LIST_HEAD(&msq->q_senders);
+ /* ipc_addid() locks msq upon success. */
+ id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
+ if (id < 0) {
+ ipc_rcu_putref(msq, msg_rcu_free);
+ return id;
+ }
+
ipc_unlock_object(&msq->q_perm);
rcu_read_unlock();
* removes the message queue from message queue ID IDR, and cleans up all the
* messages associated with this queue.
*
- * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held
- * before freeque() is called. msg_ids.rw_mutex remains locked on exit.
+ * msg_ids.rwsem (writer) and the spinlock for this message queue are held
+ * before freeque() is called. msg_ids.rwsem remains locked on exit.
*/
static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
{
expunge_all(msq, -EIDRM);
ss_wakeup(&msq->q_senders, 1);
msg_rmid(ns, msq);
- msg_unlock(msq);
+ ipc_unlock_object(&msq->q_perm);
+ rcu_read_unlock();
list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
atomic_dec(&ns->msg_hdrs);
free_msg(msg);
}
atomic_sub(msq->q_cbytes, &ns->msg_bytes);
- security_msg_queue_free(msq);
- ipc_rcu_putref(msq);
+ ipc_rcu_putref(msq, msg_rcu_free);
}
/*
- * Called with msg_ids.rw_mutex and ipcp locked.
+ * Called with msg_ids.rwsem and ipcp locked.
*/
static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
{
}
/*
- * This function handles some msgctl commands which require the rw_mutex
+ * This function handles some msgctl commands which require the rwsem
* to be held in write mode.
- * NOTE: no locks must be held, the rw_mutex is taken inside this function.
+ * NOTE: no locks must be held, the rwsem is taken inside this function.
*/
static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
struct msqid_ds __user *buf, int version)
return -EFAULT;
}
- down_write(&msg_ids(ns).rw_mutex);
+ down_write(&msg_ids(ns).rwsem);
rcu_read_lock();
ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
out_unlock1:
rcu_read_unlock();
out_up:
- up_write(&msg_ids(ns).rw_mutex);
+ up_write(&msg_ids(ns).rwsem);
return err;
}
msginfo.msgmnb = ns->msg_ctlmnb;
msginfo.msgssz = MSGSSZ;
msginfo.msgseg = MSGSEG;
- down_read(&msg_ids(ns).rw_mutex);
+ down_read(&msg_ids(ns).rwsem);
if (cmd == MSG_INFO) {
msginfo.msgpool = msg_ids(ns).in_use;
msginfo.msgmap = atomic_read(&ns->msg_hdrs);
msginfo.msgtql = MSGTQL;
}
max_id = ipc_get_maxid(&msg_ids(ns));
- up_read(&msg_ids(ns).rw_mutex);
+ up_read(&msg_ids(ns).rwsem);
if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
return -EFAULT;
return (max_id < 0) ? 0 : max_id;
if (!buf)
return -EFAULT;
+ memset(&tbuf, 0, sizeof(tbuf));
+
+ rcu_read_lock();
if (cmd == MSG_STAT) {
- msq = msg_lock(ns, msqid);
- if (IS_ERR(msq))
- return PTR_ERR(msq);
+ msq = msq_obtain_object(ns, msqid);
+ if (IS_ERR(msq)) {
+ err = PTR_ERR(msq);
+ goto out_unlock;
+ }
success_return = msq->q_perm.id;
} else {
- msq = msg_lock_check(ns, msqid);
- if (IS_ERR(msq))
- return PTR_ERR(msq);
+ msq = msq_obtain_object_check(ns, msqid);
+ if (IS_ERR(msq)) {
+ err = PTR_ERR(msq);
+ goto out_unlock;
+ }
success_return = 0;
}
+
err = -EACCES;
if (ipcperms(ns, &msq->q_perm, S_IRUGO))
goto out_unlock;
if (err)
goto out_unlock;
- memset(&tbuf, 0, sizeof(tbuf));
-
kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
tbuf.msg_stime = msq->q_stime;
tbuf.msg_rtime = msq->q_rtime;
tbuf.msg_qbytes = msq->q_qbytes;
tbuf.msg_lspid = msq->q_lspid;
tbuf.msg_lrpid = msq->q_lrpid;
- msg_unlock(msq);
+ rcu_read_unlock();
+
if (copy_msqid_to_user(buf, &tbuf, version))
return -EFAULT;
return success_return;
return err;
out_unlock:
- msg_unlock(msq);
+ rcu_read_unlock();
return err;
}
msg->m_type = mtype;
msg->m_ts = msgsz;
- msq = msg_lock_check(ns, msqid);
+ rcu_read_lock();
+ msq = msq_obtain_object_check(ns, msqid);
if (IS_ERR(msq)) {
err = PTR_ERR(msq);
- goto out_free;
+ goto out_unlock1;
}
+ ipc_lock_object(&msq->q_perm);
+
for (;;) {
struct msg_sender s;
err = -EACCES;
if (ipcperms(ns, &msq->q_perm, S_IWUGO))
- goto out_unlock_free;
+ goto out_unlock0;
+
+ /* raced with RMID? */
+ if (msq->q_perm.deleted) {
+ err = -EIDRM;
+ goto out_unlock0;
+ }
err = security_msg_queue_msgsnd(msq, msg, msgflg);
if (err)
- goto out_unlock_free;
+ goto out_unlock0;
if (msgsz + msq->q_cbytes <= msq->q_qbytes &&
1 + msq->q_qnum <= msq->q_qbytes) {
/* queue full, wait: */
if (msgflg & IPC_NOWAIT) {
err = -EAGAIN;
- goto out_unlock_free;
+ goto out_unlock0;
}
+
ss_add(msq, &s);
if (!ipc_rcu_getref(msq)) {
err = -EIDRM;
- goto out_unlock_free;
+ goto out_unlock0;
}
- msg_unlock(msq);
+ ipc_unlock_object(&msq->q_perm);
+ rcu_read_unlock();
schedule();
- ipc_lock_by_ptr(&msq->q_perm);
- ipc_rcu_putref(msq);
+ rcu_read_lock();
+ ipc_lock_object(&msq->q_perm);
+
+ ipc_rcu_putref(msq, ipc_rcu_free);
if (msq->q_perm.deleted) {
err = -EIDRM;
- goto out_unlock_free;
+ goto out_unlock0;
}
+
ss_del(&s);
if (signal_pending(current)) {
err = -ERESTARTNOHAND;
- goto out_unlock_free;
+ goto out_unlock0;
}
- }
+ }
msq->q_lspid = task_tgid_vnr(current);
msq->q_stime = get_seconds();
err = 0;
msg = NULL;
-out_unlock_free:
- msg_unlock(msq);
-out_free:
+out_unlock0:
+ ipc_unlock_object(&msq->q_perm);
+out_unlock1:
+ rcu_read_unlock();
if (msg != NULL)
free_msg(msg);
return err;
return found ?: ERR_PTR(-EAGAIN);
}
-
-long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
- int msgflg,
+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))
{
- struct msg_queue *msq;
- struct msg_msg *msg;
int mode;
+ struct msg_queue *msq;
struct ipc_namespace *ns;
- struct msg_msg *copy = NULL;
+ struct msg_msg *msg, *copy = NULL;
ns = current->nsproxy->ipc_ns;
if (msqid < 0 || (long) bufsz < 0)
return -EINVAL;
+
if (msgflg & MSG_COPY) {
+ if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT))
+ return -EINVAL;
copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
if (IS_ERR(copy))
return PTR_ERR(copy);
}
mode = convert_mode(&msgtyp, msgflg);
- msq = msg_lock_check(ns, msqid);
+ rcu_read_lock();
+ msq = msq_obtain_object_check(ns, msqid);
if (IS_ERR(msq)) {
+ rcu_read_unlock();
free_copy(copy);
return PTR_ERR(msq);
}
msg = ERR_PTR(-EACCES);
if (ipcperms(ns, &msq->q_perm, S_IRUGO))
- goto out_unlock;
+ goto out_unlock1;
- msg = find_msg(msq, &msgtyp, mode);
+ ipc_lock_object(&msq->q_perm);
+
+ /* raced with RMID? */
+ if (msq->q_perm.deleted) {
+ msg = ERR_PTR(-EIDRM);
+ goto out_unlock0;
+ }
+ msg = find_msg(msq, &msgtyp, mode);
if (!IS_ERR(msg)) {
/*
* Found a suitable message.
*/
if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
msg = ERR_PTR(-E2BIG);
- goto out_unlock;
+ goto out_unlock0;
}
/*
* If we are copying, then do not unlink message and do
*/
if (msgflg & MSG_COPY) {
msg = copy_msg(msg, copy);
- goto out_unlock;
+ goto out_unlock0;
}
+
list_del(&msg->m_list);
msq->q_qnum--;
msq->q_rtime = get_seconds();
atomic_sub(msg->m_ts, &ns->msg_bytes);
atomic_dec(&ns->msg_hdrs);
ss_wakeup(&msq->q_senders, 0);
- msg_unlock(msq);
- break;
+
+ goto out_unlock0;
}
+
/* No message waiting. Wait for a message */
if (msgflg & IPC_NOWAIT) {
msg = ERR_PTR(-ENOMSG);
- goto out_unlock;
+ goto out_unlock0;
}
+
list_add_tail(&msr_d.r_list, &msq->q_receivers);
msr_d.r_tsk = current;
msr_d.r_msgtype = msgtyp;
msr_d.r_maxsize = bufsz;
msr_d.r_msg = ERR_PTR(-EAGAIN);
current->state = TASK_INTERRUPTIBLE;
- msg_unlock(msq);
+ ipc_unlock_object(&msq->q_perm);
+ rcu_read_unlock();
schedule();
/* Lockless receive, part 1:
* Prior to destruction, expunge_all(-EIRDM) changes r_msg.
* Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
* rcu_read_lock() prevents preemption between reading r_msg
- * and the spin_lock() inside ipc_lock_by_ptr().
+ * and acquiring the q_perm.lock in ipc_lock_object().
*/
rcu_read_lock();
* If there is a message or an error then accept it without
* locking.
*/
- if (msg != ERR_PTR(-EAGAIN)) {
- rcu_read_unlock();
- break;
- }
+ if (msg != ERR_PTR(-EAGAIN))
+ goto out_unlock1;
/* Lockless receive, part 3:
* Acquire the queue spinlock.
*/
- ipc_lock_by_ptr(&msq->q_perm);
- rcu_read_unlock();
+ ipc_lock_object(&msq->q_perm);
/* Lockless receive, part 4:
* Repeat test after acquiring the spinlock.
*/
msg = (struct msg_msg*)msr_d.r_msg;
if (msg != ERR_PTR(-EAGAIN))
- goto out_unlock;
+ goto out_unlock0;
list_del(&msr_d.r_list);
if (signal_pending(current)) {
msg = ERR_PTR(-ERESTARTNOHAND);
-out_unlock:
- msg_unlock(msq);
- break;
+ goto out_unlock0;
}
+
+ ipc_unlock_object(&msq->q_perm);
}
+
+out_unlock0:
+ ipc_unlock_object(&msq->q_perm);
+out_unlock1:
+ rcu_read_unlock();
if (IS_ERR(msg)) {
free_copy(copy);
return PTR_ERR(msg);