ipc: add msgrcv syscall/compat_syscall wrappers
Provide ksys_msgrcv() and compat_ksys_msgrcv() wrappers to avoid in-kernel
calls to these syscalls. The ksys_ prefix denotes that these functions are
meant as a drop-in replacement for the syscalls. In particular, they use
the same calling convention as sys_msgrcv() and compat_sys_msgrcv().
This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
diff --git a/ipc/msg.c b/ipc/msg.c
index 5b02686..abc5826 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -1150,10 +1150,16 @@
return bufsz;
}
+long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
+ long msgtyp, int msgflg)
+{
+ return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
+}
+
SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
long, msgtyp, int, msgflg)
{
- return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
+ return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
}
#ifdef CONFIG_COMPAT
@@ -1171,12 +1177,19 @@
return msgsz;
}
-COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
- compat_ssize_t, msgsz, compat_long_t, msgtyp, int, msgflg)
+long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
+ compat_long_t msgtyp, int msgflg)
{
return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp,
msgflg, compat_do_msg_fill);
}
+
+COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
+ compat_ssize_t, msgsz, compat_long_t, msgtyp,
+ int, msgflg)
+{
+ return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
+}
#endif
int msg_init_ns(struct ipc_namespace *ns)