Commit e340db56 authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

ipc: add msgctl syscall/compat_syscall wrappers 

Provide ksys_msgctl() and compat_ksys_msgctl() 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_msgctl() and compat_sys_msgctl().

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: default avatarDominik Brodowski <linux@dominikbrodowski.net>
parent c84d0791

ipc/msg.c

+12 −2
Original line number Diff line number Diff line
@@ -538,7 +538,7 @@ static int msgctl_stat(struct ipc_namespace *ns, int msqid, 
	return err;

}



SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)

long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)

{

	int version;

	struct ipc_namespace *ns;
@@ -581,6 +581,11 @@ SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) 
	}

}



SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)

{

	return ksys_msgctl(msqid, cmd, buf);

}



#ifdef CONFIG_COMPAT



struct compat_msqid_ds {
@@ -651,7 +656,7 @@ static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in, 
	}

}



COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)

long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr)

{

	struct ipc_namespace *ns;

	int err;
@@ -692,6 +697,11 @@ COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr) 
		return -EINVAL;

	}

}



COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)

{

	return compat_ksys_msgctl(msqid, cmd, uptr);

}

#endif



static int testmsg(struct msg_msg *msg, long type, int mode)

ipc/syscall.c

+3 −2
Original line number Diff line number Diff line
@@ -70,7 +70,8 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second, 
	case MSGGET:

		return ksys_msgget((key_t) first, second);

	case MSGCTL:

		return sys_msgctl(first, second, (struct msqid_ds __user *)ptr);

		return ksys_msgctl(first, second,

				   (struct msqid_ds __user *)ptr);



	case SHMAT:

		switch (version) {
@@ -163,7 +164,7 @@ COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second, 
	case MSGGET:

		return ksys_msgget(first, second);

	case MSGCTL:

		return compat_sys_msgctl(first, second, compat_ptr(ptr));

		return compat_ksys_msgctl(first, second, compat_ptr(ptr));



	case SHMAT: {

		int err;

ipc/util.h

+2 −0
Original line number Diff line number Diff line
@@ -243,6 +243,7 @@ long ksys_semtimedop(int semid, struct sembuf __user *tsops, 
long ksys_semget(key_t key, int nsems, int semflg);

long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg);

long ksys_msgget(key_t key, int msgflg);

long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf);

long ksys_shmget(key_t key, size_t size, int shmflg);

long ksys_shmdt(char __user *shmaddr);

long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf);
@@ -253,6 +254,7 @@ long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems, 
			    unsigned int nsops,

			    const struct compat_timespec __user *timeout);

long compat_ksys_semctl(int semid, int semnum, int cmd, int arg);

long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr);

long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr);

#endif /* CONFIG_COMPAT */