Commit c84d0791 authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

ipc: add shmctl syscall/compat_syscall wrappers 

Provide ksys_shmctl() and compat_ksys_shmctl() 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_shmctl() and compat_sys_shmctl().

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 da1e2744

ipc/shm.c

+12 −2
Original line number Diff line number Diff line
@@ -1045,7 +1045,7 @@ static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd) 
	return err;

}



SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)

long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)

{

	int err, version;

	struct ipc_namespace *ns;
@@ -1099,6 +1099,11 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) 
	}

}



SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)

{

	return ksys_shmctl(shmid, cmd, buf);

}



#ifdef CONFIG_COMPAT



struct compat_shmid_ds {
@@ -1218,7 +1223,7 @@ static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf, 
	}

}



COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)

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

{

	struct ipc_namespace *ns;

	struct shmid64_ds sem64;
@@ -1273,6 +1278,11 @@ COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr) 
	}

	return err;

}



COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)

{

	return compat_ksys_shmctl(shmid, cmd, uptr);

}

#endif



/*

ipc/syscall.c

+2 −2
Original line number Diff line number Diff line
@@ -94,7 +94,7 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second, 
	case SHMGET:

		return ksys_shmget(first, second, third);

	case SHMCTL:

		return sys_shmctl(first, second,

		return ksys_shmctl(first, second,

				   (struct shmid_ds __user *) ptr);

	default:

		return -ENOSYS;
@@ -182,7 +182,7 @@ COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second, 
	case SHMGET:

		return ksys_shmget(first, (unsigned int)second, third);

	case SHMCTL:

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

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

	}



	return -ENOSYS;

ipc/util.h

+2 −0
Original line number Diff line number Diff line
@@ -245,6 +245,7 @@ long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg); 
long ksys_msgget(key_t key, int msgflg);

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);



/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */

#ifdef CONFIG_COMPAT
@@ -252,6 +253,7 @@ 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_shmctl(int shmid, int cmd, void __user *uptr);

#endif /* CONFIG_COMPAT */



#endif