ipc: message queue receive cleanup

Move all message related manipulation into one function msg_fill().
Actually, two functions because of the compat one.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/msg.h b/include/linux/msg.h
index 7a4b9e97d29a0782ef0dde63126f6a124eeb848b..f38edba4de6d8e9b0836c6e4ae65516290f10812 100644 (file)
--- a/include/linux/msg.h
+++ b/include/linux/msg.h
@@ -34,7 +34,8 @@ struct msg_queue {
 /* Helper routines for sys_msgsnd and sys_msgrcv */
 extern long do_msgsnd(int msqid, long mtype, void __user *mtext,
                        size_t msgsz, int msgflg);
-extern long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
-                       size_t msgsz, long msgtyp, int msgflg);
+extern long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
+                     int msgflg,
+                     long (*msg_fill)(void __user *, struct msg_msg *, size_t ));
 
 #endif /* _LINUX_MSG_H */

diff --git a/ipc/compat.c b/ipc/compat.c
index ad9518eb26e06e648c6044b95de41d39e9b076d0..eb3ea16d2d1dd351d69c27156d096578188938f8 100644 (file)
--- a/ipc/compat.c
+++ b/ipc/compat.c
@@ -306,6 +306,20 @@ static long do_compat_semctl(int first, int second, int third, u32 pad)
        return err;
 }
 
+long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
+{
+       struct compat_msgbuf __user *msgp = dest;
+       size_t msgsz;
+
+       if (put_user(msg->m_type, &msgp->mtype))
+               return -EFAULT;
+
+       msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
+       if (store_msg(msgp->mtext, msg, msgsz))
+               return -EFAULT;
+       return msgsz;
+}
+
 #ifdef CONFIG_ARCH_WANT_OLD_COMPAT_IPC
 long compat_sys_semctl(int first, int second, int third, void __user *uptr)
 {
@@ -337,10 +351,6 @@ long compat_sys_msgsnd(int first, int second, int third, void __user *uptr)
 long compat_sys_msgrcv(int first, int second, int msgtyp, int third,
                           int version, void __user *uptr)
 {
-       struct compat_msgbuf __user *up;
-       long type;
-       int err;
-
        if (first < 0)
                return -EINVAL;
        if (second < 0)
@@ -348,23 +358,14 @@ long compat_sys_msgrcv(int first, int second, int msgtyp, int third,
 
        if (!version) {
                struct compat_ipc_kludge ipck;
-               err = -EINVAL;
                if (!uptr)
-                       goto out;
-               err = -EFAULT;
+                       return -EINVAL;
                if (copy_from_user (&ipck, uptr, sizeof(ipck)))
-                       goto out;
+                       return -EFAULT;
                uptr = compat_ptr(ipck.msgp);
                msgtyp = ipck.msgtyp;
        }
-       up = uptr;
-       err = do_msgrcv(first, &type, up->mtext, second, msgtyp, third);
-       if (err < 0)
-               goto out;
-       if (put_user(type, &up->mtype))
-               err = -EFAULT;
-out:
-       return err;
+       return do_msgrcv(first, uptr, second, msgtyp, third, compat_do_msg_fill);
 }
 #else
 long compat_sys_semctl(int semid, int semnum, int cmd, int arg)
@@ -385,16 +386,8 @@ long compat_sys_msgsnd(int msqid, struct compat_msgbuf __user *msgp,
 long compat_sys_msgrcv(int msqid, struct compat_msgbuf __user *msgp,
                       compat_ssize_t msgsz, long msgtyp, int msgflg)
 {
-       long err, mtype;
-
-       err =  do_msgrcv(msqid, &mtype, msgp->mtext, (ssize_t)msgsz, msgtyp, msgflg);
-       if (err < 0)
-               goto out;
-
-       if (put_user(mtype, &msgp->mtype))
-               err = -EFAULT;
- out:
-       return err;
+       return do_msgrcv(msqid, msgp, (ssize_t)msgsz, msgtyp, msgflg,
+                        compat_do_msg_fill);
 }
 #endif
 

diff --git a/ipc/msg.c b/ipc/msg.c
index 2f272fa76595656054e511b0c66476c84769a213..532ebc3e3cfec7638ae5ee0a627098f626bdd2ee 100644 (file)
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -755,15 +755,30 @@ static inline int convert_mode(long *msgtyp, int msgflg)
        return SEARCH_EQUAL;
 }
 
-long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
-               size_t msgsz, long msgtyp, int msgflg)
+static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
+{
+       struct msgbuf __user *msgp = dest;
+       size_t msgsz;
+
+       if (put_user(msg->m_type, &msgp->mtype))
+               return -EFAULT;
+
+       msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
+       if (store_msg(msgp->mtext, msg, msgsz))
+               return -EFAULT;
+       return msgsz;
+}
+
+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 ipc_namespace *ns;
 
-       if (msqid < 0 || (long) msgsz < 0)
+       if (msqid < 0 || (long) bufsz < 0)
                return -EINVAL;
        mode = convert_mode(&msgtyp, msgflg);
        ns = current->nsproxy->ipc_ns;
@@ -804,7 +819,7 @@ long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
                         * Found a suitable message.
                         * Unlink it from the queue.
                         */
-                       if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
+                       if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
                                msg = ERR_PTR(-E2BIG);
                                goto out_unlock;
                        }
@@ -831,7 +846,7 @@ long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
                if (msgflg & MSG_NOERROR)
                        msr_d.r_maxsize = INT_MAX;
                else
-                       msr_d.r_maxsize = msgsz;
+                       msr_d.r_maxsize = bufsz;
                msr_d.r_msg = ERR_PTR(-EAGAIN);
                current->state = TASK_INTERRUPTIBLE;
                msg_unlock(msq);
@@ -894,29 +909,16 @@ out_unlock:
        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;
-
+       bufsz = msg_handler(buf, msg, bufsz);
        free_msg(msg);
 
-       return msgsz;
+       return bufsz;
 }
 
 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;
+       return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
 }
 
 #ifdef CONFIG_PROC_FS