[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/ipc/msg.c b/ap/os/linux/linux-3.4.x/ipc/msg.c
new file mode 100755
index 0000000..a1cf543
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/ipc/msg.c
@@ -0,0 +1,965 @@
+/*
+ * linux/ipc/msg.c
+ * Copyright (C) 1992 Krishna Balasubramanian
+ *
+ * Removed all the remaining kerneld mess
+ * Catch the -EFAULT stuff properly
+ * Use GFP_KERNEL for messages as in 1.2
+ * Fixed up the unchecked user space derefs
+ * Copyright (C) 1998 Alan Cox & Andi Kleen
+ *
+ * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
+ *
+ * mostly rewritten, threaded and wake-one semantics added
+ * MSGMAX limit removed, sysctl's added
+ * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
+ *
+ * support for audit of ipc object properties and permission changes
+ * Dustin Kirkland <dustin.kirkland@us.ibm.com>
+ *
+ * namespaces support
+ * OpenVZ, SWsoft Inc.
+ * Pavel Emelianov <xemul@openvz.org>
+ */
+
+#include <linux/capability.h>
+#include <linux/msg.h>
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/list.h>
+#include <linux/security.h>
+#include <linux/sched.h>
+#include <linux/syscalls.h>
+#include <linux/audit.h>
+#include <linux/seq_file.h>
+#include <linux/rwsem.h>
+#include <linux/nsproxy.h>
+#include <linux/ipc_namespace.h>
+
+#include <asm/current.h>
+#include <asm/uaccess.h>
+#include "util.h"
+
+/*
+ * one msg_receiver structure for each sleeping receiver:
+ */
+struct msg_receiver {
+ struct list_head r_list;
+ struct task_struct *r_tsk;
+
+ int r_mode;
+ long r_msgtype;
+ long r_maxsize;
+
+ struct msg_msg *volatile r_msg;
+};
+
+/* one msg_sender for each sleeping sender */
+struct msg_sender {
+ struct list_head list;
+ struct task_struct *tsk;
+};
+
+#define SEARCH_ANY 1
+#define SEARCH_EQUAL 2
+#define SEARCH_NOTEQUAL 3
+#define SEARCH_LESSEQUAL 4
+
+#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
+static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
+#endif
+
+/*
+ * Scale msgmni with the available lowmem size: the memory dedicated to msg
+ * queues should occupy at most 1/MSG_MEM_SCALE of lowmem.
+ * Also take into account the number of nsproxies created so far.
+ * This should be done staying within the (MSGMNI , IPCMNI/nr_ipc_ns) range.
+ */
+void recompute_msgmni(struct ipc_namespace *ns)
+{
+ struct sysinfo i;
+ unsigned long allowed;
+ int nb_ns;
+
+ si_meminfo(&i);
+ allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit)
+ / MSGMNB;
+ nb_ns = atomic_read(&nr_ipc_ns);
+ allowed /= nb_ns;
+
+ if (allowed < MSGMNI) {
+ ns->msg_ctlmni = MSGMNI;
+ return;
+ }
+
+ if (allowed > IPCMNI / nb_ns) {
+ ns->msg_ctlmni = IPCMNI / nb_ns;
+ return;
+ }
+
+ ns->msg_ctlmni = allowed;
+}
+
+void msg_init_ns(struct ipc_namespace *ns)
+{
+ ns->msg_ctlmax = MSGMAX;
+ ns->msg_ctlmnb = MSGMNB;
+
+ recompute_msgmni(ns);
+
+ atomic_set(&ns->msg_bytes, 0);
+ atomic_set(&ns->msg_hdrs, 0);
+ ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
+}
+
+#ifdef CONFIG_IPC_NS
+void msg_exit_ns(struct ipc_namespace *ns)
+{
+ free_ipcs(ns, &msg_ids(ns), freeque);
+ idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
+}
+#endif
+
+void __init msg_init(void)
+{
+ msg_init_ns(&init_ipc_ns);
+
+ printk(KERN_INFO "msgmni has been set to %d\n",
+ init_ipc_ns.msg_ctlmni);
+
+ if (IS_ENABLED(CONFIG_PROC_STRIPPED))
+ return 0;
+
+ ipc_init_proc_interface("sysvipc/msg",
+ " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
+ 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 void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
+{
+ ipc_rmid(&msg_ids(ns), &s->q_perm);
+}
+
+/**
+ * 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)
+ */
+static int newque(struct ipc_namespace *ns, struct ipc_params *params)
+{
+ struct msg_queue *msq;
+ int id, retval;
+ key_t key = params->key;
+ int msgflg = params->flg;
+
+ msq = ipc_rcu_alloc(sizeof(*msq));
+ if (!msq)
+ return -ENOMEM;
+
+ msq->q_perm.mode = msgflg & S_IRWXUGO;
+ msq->q_perm.key = key;
+
+ msq->q_perm.security = NULL;
+ retval = security_msg_queue_alloc(msq);
+ if (retval) {
+ ipc_rcu_putref(msq);
+ return retval;
+ }
+
+ /*
+ * ipc_addid() locks msq
+ */
+ 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;
+ msq->q_qbytes = ns->msg_ctlmnb;
+ msq->q_lspid = msq->q_lrpid = 0;
+ INIT_LIST_HEAD(&msq->q_messages);
+ INIT_LIST_HEAD(&msq->q_receivers);
+ INIT_LIST_HEAD(&msq->q_senders);
+
+ msg_unlock(msq);
+
+ return msq->q_perm.id;
+}
+
+static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss)
+{
+ mss->tsk = current;
+ current->state = TASK_INTERRUPTIBLE;
+ list_add_tail(&mss->list, &msq->q_senders);
+}
+
+static inline void ss_del(struct msg_sender *mss)
+{
+ if (mss->list.next != NULL)
+ list_del(&mss->list);
+}
+
+static void ss_wakeup(struct list_head *h, int kill)
+{
+ struct list_head *tmp;
+
+ tmp = h->next;
+ while (tmp != h) {
+ struct msg_sender *mss;
+
+ mss = list_entry(tmp, struct msg_sender, list);
+ tmp = tmp->next;
+ if (kill)
+ mss->list.next = NULL;
+ wake_up_process(mss->tsk);
+ }
+}
+
+static void expunge_all(struct msg_queue *msq, int res)
+{
+ struct list_head *tmp;
+
+ tmp = msq->q_receivers.next;
+ while (tmp != &msq->q_receivers) {
+ struct msg_receiver *msr;
+
+ /*
+ * Make sure that the wakeup doesnt preempt
+ * this CPU prematurely. (on PREEMPT_RT)
+ */
+ preempt_disable_rt();
+
+ msr = list_entry(tmp, struct msg_receiver, r_list);
+ tmp = tmp->next;
+ msr->r_msg = NULL;
+ wake_up_process(msr->r_tsk);
+ smp_mb();
+ msr->r_msg = ERR_PTR(res);
+
+ preempt_enable_rt();
+ }
+}
+
+/*
+ * freeque() wakes up waiters on the sender and receiver waiting queue,
+ * 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.
+ */
+static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
+{
+ struct list_head *tmp;
+ struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
+
+ expunge_all(msq, -EIDRM);
+ ss_wakeup(&msq->q_senders, 1);
+ msg_rmid(ns, msq);
+ msg_unlock(msq);
+
+ tmp = msq->q_messages.next;
+ while (tmp != &msq->q_messages) {
+ struct msg_msg *msg = list_entry(tmp, struct msg_msg, m_list);
+
+ tmp = tmp->next;
+ atomic_dec(&ns->msg_hdrs);
+ free_msg(msg);
+ }
+ atomic_sub(msq->q_cbytes, &ns->msg_bytes);
+ security_msg_queue_free(msq);
+ ipc_lock_by_ptr(&msq->q_perm);
+ ipc_rcu_putref(msq);
+ ipc_unlock(&msq->q_perm);
+}
+
+/*
+ * Called with msg_ids.rw_mutex and ipcp locked.
+ */
+static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
+{
+ struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
+
+ return security_msg_queue_associate(msq, msgflg);
+}
+
+SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
+{
+ struct ipc_namespace *ns;
+ struct ipc_ops msg_ops;
+ struct ipc_params msg_params;
+
+ ns = current->nsproxy->ipc_ns;
+
+ msg_ops.getnew = newque;
+ msg_ops.associate = msg_security;
+ msg_ops.more_checks = NULL;
+
+ msg_params.key = key;
+ msg_params.flg = msgflg;
+
+ return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
+}
+
+static inline unsigned long
+copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
+{
+ switch(version) {
+ case IPC_64:
+ return copy_to_user(buf, in, sizeof(*in));
+ case IPC_OLD:
+ {
+ struct msqid_ds out;
+
+ memset(&out, 0, sizeof(out));
+
+ ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
+
+ out.msg_stime = in->msg_stime;
+ out.msg_rtime = in->msg_rtime;
+ out.msg_ctime = in->msg_ctime;
+
+ if (in->msg_cbytes > USHRT_MAX)
+ out.msg_cbytes = USHRT_MAX;
+ else
+ out.msg_cbytes = in->msg_cbytes;
+ out.msg_lcbytes = in->msg_cbytes;
+
+ if (in->msg_qnum > USHRT_MAX)
+ out.msg_qnum = USHRT_MAX;
+ else
+ out.msg_qnum = in->msg_qnum;
+
+ if (in->msg_qbytes > USHRT_MAX)
+ out.msg_qbytes = USHRT_MAX;
+ else
+ out.msg_qbytes = in->msg_qbytes;
+ out.msg_lqbytes = in->msg_qbytes;
+
+ out.msg_lspid = in->msg_lspid;
+ out.msg_lrpid = in->msg_lrpid;
+
+ return copy_to_user(buf, &out, sizeof(out));
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static inline unsigned long
+copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
+{
+ switch(version) {
+ case IPC_64:
+ if (copy_from_user(out, buf, sizeof(*out)))
+ return -EFAULT;
+ return 0;
+ case IPC_OLD:
+ {
+ struct msqid_ds tbuf_old;
+
+ if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
+ return -EFAULT;
+
+ out->msg_perm.uid = tbuf_old.msg_perm.uid;
+ out->msg_perm.gid = tbuf_old.msg_perm.gid;
+ out->msg_perm.mode = tbuf_old.msg_perm.mode;
+
+ if (tbuf_old.msg_qbytes == 0)
+ out->msg_qbytes = tbuf_old.msg_lqbytes;
+ else
+ out->msg_qbytes = tbuf_old.msg_qbytes;
+
+ return 0;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+/*
+ * This function handles some msgctl commands which require the rw_mutex
+ * to be held in write mode.
+ * NOTE: no locks must be held, the rw_mutex is taken inside this function.
+ */
+static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
+ struct msqid_ds __user *buf, int version)
+{
+ struct kern_ipc_perm *ipcp;
+ struct msqid64_ds uninitialized_var(msqid64);
+ struct msg_queue *msq;
+ int err;
+
+ if (cmd == IPC_SET) {
+ if (copy_msqid_from_user(&msqid64, buf, version))
+ return -EFAULT;
+ }
+
+ ipcp = ipcctl_pre_down(ns, &msg_ids(ns), msqid, cmd,
+ &msqid64.msg_perm, msqid64.msg_qbytes);
+ if (IS_ERR(ipcp))
+ return PTR_ERR(ipcp);
+
+ msq = container_of(ipcp, struct msg_queue, q_perm);
+
+ err = security_msg_queue_msgctl(msq, cmd);
+ if (err)
+ goto out_unlock;
+
+ switch (cmd) {
+ case IPC_RMID:
+ freeque(ns, ipcp);
+ goto out_up;
+ case IPC_SET:
+ if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
+ !capable(CAP_SYS_RESOURCE)) {
+ err = -EPERM;
+ goto out_unlock;
+ }
+
+ msq->q_qbytes = msqid64.msg_qbytes;
+
+ ipc_update_perm(&msqid64.msg_perm, ipcp);
+ msq->q_ctime = get_seconds();
+ /* sleeping receivers might be excluded by
+ * stricter permissions.
+ */
+ expunge_all(msq, -EAGAIN);
+ /* sleeping senders might be able to send
+ * due to a larger queue size.
+ */
+ ss_wakeup(&msq->q_senders, 0);
+ break;
+ default:
+ err = -EINVAL;
+ }
+out_unlock:
+ msg_unlock(msq);
+out_up:
+ up_write(&msg_ids(ns).rw_mutex);
+ return err;
+}
+
+SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
+{
+ struct msg_queue *msq;
+ int err, version;
+ struct ipc_namespace *ns;
+
+ if (msqid < 0 || cmd < 0)
+ return -EINVAL;
+
+ version = ipc_parse_version(&cmd);
+ ns = current->nsproxy->ipc_ns;
+
+ switch (cmd) {
+ case IPC_INFO:
+ case MSG_INFO:
+ {
+ struct msginfo msginfo;
+ int max_id;
+
+ if (!buf)
+ return -EFAULT;
+ /*
+ * We must not return kernel stack data.
+ * due to padding, it's not enough
+ * to set all member fields.
+ */
+ err = security_msg_queue_msgctl(NULL, cmd);
+ if (err)
+ return err;
+
+ memset(&msginfo, 0, sizeof(msginfo));
+ msginfo.msgmni = ns->msg_ctlmni;
+ msginfo.msgmax = ns->msg_ctlmax;
+ msginfo.msgmnb = ns->msg_ctlmnb;
+ msginfo.msgssz = MSGSSZ;
+ msginfo.msgseg = MSGSEG;
+ down_read(&msg_ids(ns).rw_mutex);
+ if (cmd == MSG_INFO) {
+ msginfo.msgpool = msg_ids(ns).in_use;
+ msginfo.msgmap = atomic_read(&ns->msg_hdrs);
+ msginfo.msgtql = atomic_read(&ns->msg_bytes);
+ } else {
+ msginfo.msgmap = MSGMAP;
+ msginfo.msgpool = MSGPOOL;
+ msginfo.msgtql = MSGTQL;
+ }
+ max_id = ipc_get_maxid(&msg_ids(ns));
+ up_read(&msg_ids(ns).rw_mutex);
+ if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
+ return -EFAULT;
+ return (max_id < 0) ? 0 : max_id;
+ }
+ case MSG_STAT: /* msqid is an index rather than a msg queue id */
+ case IPC_STAT:
+ {
+ struct msqid64_ds tbuf;
+ int success_return;
+
+ if (!buf)
+ return -EFAULT;
+
+ if (cmd == MSG_STAT) {
+ msq = msg_lock(ns, msqid);
+ if (IS_ERR(msq))
+ return PTR_ERR(msq);
+ success_return = msq->q_perm.id;
+ } else {
+ msq = msg_lock_check(ns, msqid);
+ if (IS_ERR(msq))
+ return PTR_ERR(msq);
+ success_return = 0;
+ }
+ err = -EACCES;
+ if (ipcperms(ns, &msq->q_perm, S_IRUGO))
+ goto out_unlock;
+
+ err = security_msg_queue_msgctl(msq, cmd);
+ 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_ctime = msq->q_ctime;
+ tbuf.msg_cbytes = msq->q_cbytes;
+ tbuf.msg_qnum = msq->q_qnum;
+ tbuf.msg_qbytes = msq->q_qbytes;
+ tbuf.msg_lspid = msq->q_lspid;
+ tbuf.msg_lrpid = msq->q_lrpid;
+ msg_unlock(msq);
+ if (copy_msqid_to_user(buf, &tbuf, version))
+ return -EFAULT;
+ return success_return;
+ }
+ case IPC_SET:
+ case IPC_RMID:
+ err = msgctl_down(ns, msqid, cmd, buf, version);
+ return err;
+ default:
+ return -EINVAL;
+ }
+
+out_unlock:
+ msg_unlock(msq);
+ return err;
+}
+
+static int testmsg(struct msg_msg *msg, long type, int mode)
+{
+ switch(mode)
+ {
+ case SEARCH_ANY:
+ return 1;
+ case SEARCH_LESSEQUAL:
+ if (msg->m_type <=type)
+ return 1;
+ break;
+ case SEARCH_EQUAL:
+ if (msg->m_type == type)
+ return 1;
+ break;
+ case SEARCH_NOTEQUAL:
+ if (msg->m_type != type)
+ return 1;
+ break;
+ }
+ return 0;
+}
+
+static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
+{
+ struct list_head *tmp;
+
+ tmp = msq->q_receivers.next;
+ while (tmp != &msq->q_receivers) {
+ struct msg_receiver *msr;
+
+ msr = list_entry(tmp, struct msg_receiver, r_list);
+ tmp = tmp->next;
+ if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
+ !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
+ msr->r_msgtype, msr->r_mode)) {
+
+ /*
+ * Make sure that the wakeup doesnt preempt
+ * this CPU prematurely. (on PREEMPT_RT)
+ */
+ preempt_disable_rt();
+
+ list_del(&msr->r_list);
+ if (msr->r_maxsize < msg->m_ts) {
+ msr->r_msg = NULL;
+ wake_up_process(msr->r_tsk);
+ smp_mb();
+ msr->r_msg = ERR_PTR(-E2BIG);
+ } else {
+ msr->r_msg = NULL;
+ msq->q_lrpid = task_pid_vnr(msr->r_tsk);
+ msq->q_rtime = get_seconds();
+ wake_up_process(msr->r_tsk);
+ smp_mb();
+ msr->r_msg = msg;
+ preempt_enable_rt();
+
+ return 1;
+ }
+ preempt_enable_rt();
+ }
+ }
+ return 0;
+}
+
+long do_msgsnd(int msqid, long mtype, void __user *mtext,
+ size_t msgsz, int msgflg)
+{
+ struct msg_queue *msq;
+ struct msg_msg *msg;
+ int err;
+ struct ipc_namespace *ns;
+
+ ns = current->nsproxy->ipc_ns;
+
+ if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
+ return -EINVAL;
+ if (mtype < 1)
+ return -EINVAL;
+
+ msg = load_msg(mtext, msgsz);
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ msg->m_type = mtype;
+ msg->m_ts = msgsz;
+
+ msq = msg_lock_check(ns, msqid);
+ if (IS_ERR(msq)) {
+ err = PTR_ERR(msq);
+ goto out_free;
+ }
+
+ for (;;) {
+ struct msg_sender s;
+
+ err = -EACCES;
+ if (ipcperms(ns, &msq->q_perm, S_IWUGO))
+ goto out_unlock_free;
+
+ err = security_msg_queue_msgsnd(msq, msg, msgflg);
+ if (err)
+ goto out_unlock_free;
+
+ if (msgsz + msq->q_cbytes <= msq->q_qbytes &&
+ 1 + msq->q_qnum <= msq->q_qbytes) {
+ break;
+ }
+
+ /* queue full, wait: */
+ if (msgflg & IPC_NOWAIT) {
+ err = -EAGAIN;
+ goto out_unlock_free;
+ }
+ ss_add(msq, &s);
+ ipc_rcu_getref(msq);
+ msg_unlock(msq);
+ schedule();
+
+ ipc_lock_by_ptr(&msq->q_perm);
+ ipc_rcu_putref(msq);
+ if (msq->q_perm.deleted) {
+ err = -EIDRM;
+ goto out_unlock_free;
+ }
+ ss_del(&s);
+
+ if (signal_pending(current)) {
+ err = -ERESTARTNOHAND;
+ goto out_unlock_free;
+ }
+ }
+
+ msq->q_lspid = task_tgid_vnr(current);
+ msq->q_stime = get_seconds();
+
+ if (!pipelined_send(msq, msg)) {
+ /* no one is waiting for this message, enqueue it */
+ list_add_tail(&msg->m_list, &msq->q_messages);
+ msq->q_cbytes += msgsz;
+ msq->q_qnum++;
+ atomic_add(msgsz, &ns->msg_bytes);
+ atomic_inc(&ns->msg_hdrs);
+ }
+
+ err = 0;
+ msg = NULL;
+
+out_unlock_free:
+ msg_unlock(msq);
+out_free:
+ if (msg != NULL)
+ free_msg(msg);
+ return err;
+}
+
+SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
+ int, msgflg)
+{
+ long mtype;
+
+ if (get_user(mtype, &msgp->mtype))
+ return -EFAULT;
+ return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
+}
+
+static inline int convert_mode(long *msgtyp, int msgflg)
+{
+ /*
+ * find message of correct type.
+ * msgtyp = 0 => get first.
+ * msgtyp > 0 => get first message of matching type.
+ * msgtyp < 0 => get message with least type must be < abs(msgtype).
+ */
+ if (*msgtyp == 0)
+ return SEARCH_ANY;
+ if (*msgtyp < 0) {
+ *msgtyp = -*msgtyp;
+ return SEARCH_LESSEQUAL;
+ }
+ if (msgflg & MSG_EXCEPT)
+ return SEARCH_NOTEQUAL;
+ return SEARCH_EQUAL;
+}
+
+long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
+ size_t msgsz, long msgtyp, int msgflg)
+{
+ struct msg_queue *msq;
+ struct msg_msg *msg;
+ int mode;
+ struct ipc_namespace *ns;
+
+ if (msqid < 0 || (long) msgsz < 0)
+ return -EINVAL;
+ mode = convert_mode(&msgtyp, msgflg);
+ ns = current->nsproxy->ipc_ns;
+
+ msq = msg_lock_check(ns, msqid);
+ if (IS_ERR(msq))
+ return PTR_ERR(msq);
+
+ for (;;) {
+ struct msg_receiver msr_d;
+ struct list_head *tmp;
+
+ msg = ERR_PTR(-EACCES);
+ if (ipcperms(ns, &msq->q_perm, S_IRUGO))
+ goto out_unlock;
+
+ msg = ERR_PTR(-EAGAIN);
+ tmp = msq->q_messages.next;
+ while (tmp != &msq->q_messages) {
+ struct msg_msg *walk_msg;
+
+ walk_msg = list_entry(tmp, struct msg_msg, m_list);
+ if (testmsg(walk_msg, msgtyp, mode) &&
+ !security_msg_queue_msgrcv(msq, walk_msg, current,
+ msgtyp, mode)) {
+
+ msg = walk_msg;
+ if (mode == SEARCH_LESSEQUAL &&
+ walk_msg->m_type != 1) {
+ msg = walk_msg;
+ msgtyp = walk_msg->m_type - 1;
+ } else {
+ msg = walk_msg;
+ break;
+ }
+ }
+ tmp = tmp->next;
+ }
+ if (!IS_ERR(msg)) {
+ /*
+ * Found a suitable message.
+ * Unlink it from the queue.
+ */
+ if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
+ msg = ERR_PTR(-E2BIG);
+ goto out_unlock;
+ }
+ list_del(&msg->m_list);
+ msq->q_qnum--;
+ msq->q_rtime = get_seconds();
+ msq->q_lrpid = task_tgid_vnr(current);
+ msq->q_cbytes -= msg->m_ts;
+ atomic_sub(msg->m_ts, &ns->msg_bytes);
+ atomic_dec(&ns->msg_hdrs);
+ ss_wakeup(&msq->q_senders, 0);
+ msg_unlock(msq);
+ break;
+ }
+ /* No message waiting. Wait for a message */
+ if (msgflg & IPC_NOWAIT) {
+ msg = ERR_PTR(-ENOMSG);
+ goto out_unlock;
+ }
+ list_add_tail(&msr_d.r_list, &msq->q_receivers);
+ msr_d.r_tsk = current;
+ msr_d.r_msgtype = msgtyp;
+ msr_d.r_mode = mode;
+ if (msgflg & MSG_NOERROR)
+ msr_d.r_maxsize = INT_MAX;
+ else
+ msr_d.r_maxsize = msgsz;
+ msr_d.r_msg = ERR_PTR(-EAGAIN);
+ current->state = TASK_INTERRUPTIBLE;
+ msg_unlock(msq);
+
+ schedule();
+
+ /* Lockless receive, part 1:
+ * Disable preemption. We don't hold a reference to the queue
+ * and getting a reference would defeat the idea of a lockless
+ * operation, thus the code relies on rcu to guarantee the
+ * existence of msq:
+ * 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().
+ */
+ rcu_read_lock();
+
+ /* Lockless receive, part 2:
+ * Wait until pipelined_send or expunge_all are outside of
+ * wake_up_process(). There is a race with exit(), see
+ * ipc/mqueue.c for the details.
+ */
+ msg = (struct msg_msg*)msr_d.r_msg;
+ while (msg == NULL) {
+ cpu_relax();
+ msg = (struct msg_msg *)msr_d.r_msg;
+ }
+
+ /* Lockless receive, part 3:
+ * If there is a message or an error then accept it without
+ * locking.
+ */
+ if (msg != ERR_PTR(-EAGAIN)) {
+ rcu_read_unlock();
+ break;
+ }
+
+ /* Lockless receive, part 3:
+ * Acquire the queue spinlock.
+ */
+ ipc_lock_by_ptr(&msq->q_perm);
+ rcu_read_unlock();
+
+ /* 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;
+
+ list_del(&msr_d.r_list);
+ if (signal_pending(current)) {
+ msg = ERR_PTR(-ERESTARTNOHAND);
+out_unlock:
+ msg_unlock(msq);
+ break;
+ }
+ }
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz;
+ *pmtype = msg->m_type;
+ if (store_msg(mtext, msg, msgsz))
+ msgsz = -EFAULT;
+
+ free_msg(msg);
+
+ return msgsz;
+}
+
+SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
+ long, msgtyp, int, msgflg)
+{
+ long err, mtype;
+
+ err = do_msgrcv(msqid, &mtype, msgp->mtext, msgsz, msgtyp, msgflg);
+ if (err < 0)
+ goto out;
+
+ if (put_user(mtype, &msgp->mtype))
+ err = -EFAULT;
+out:
+ return err;
+}
+
+#ifdef CONFIG_PROC_FS
+static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
+{
+ struct msg_queue *msq = it;
+
+ return seq_printf(s,
+ "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
+ msq->q_perm.key,
+ msq->q_perm.id,
+ msq->q_perm.mode,
+ msq->q_cbytes,
+ msq->q_qnum,
+ msq->q_lspid,
+ msq->q_lrpid,
+ msq->q_perm.uid,
+ msq->q_perm.gid,
+ msq->q_perm.cuid,
+ msq->q_perm.cgid,
+ msq->q_stime,
+ msq->q_rtime,
+ msq->q_ctime);
+}
+#endif