Commit 65749e0b authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

ipc: add shmget syscall wrapper 

Provide ksys_shmget() wrapper to avoid in-kernel calls to this syscall.
The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_shmget().

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 3d65661a

ipc/shm.c

+6 −1
Original line number Diff line number Diff line
@@ -656,7 +656,7 @@ static inline int shm_more_checks(struct kern_ipc_perm *ipcp, 
	return 0;

}



SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)

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

{

	struct ipc_namespace *ns;

	static const struct ipc_ops shm_ops = {
@@ -675,6 +675,11 @@ SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg) 
	return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);

}



SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)

{

	return ksys_shmget(key, size, shmflg);

}



static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)

{

	switch (version) {

ipc/syscall.c

+2 −2
Original line number Diff line number Diff line
@@ -92,7 +92,7 @@ SYSCALL_DEFINE6(ipc, unsigned int, call, int, first, unsigned long, second, 
	case SHMDT:

		return sys_shmdt((char __user *)ptr);

	case SHMGET:

		return sys_shmget(first, second, third);

		return ksys_shmget(first, second, third);

	case SHMCTL:

		return sys_shmctl(first, second,

				   (struct shmid_ds __user *) ptr);
@@ -180,7 +180,7 @@ COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second, 
	case SHMDT:

		return sys_shmdt(compat_ptr(ptr));

	case SHMGET:

		return sys_shmget(first, (unsigned)second, third);

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

	case SHMCTL:

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

	}

ipc/util.h

+1 −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_shmget(key_t key, size_t size, int shmflg);



/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */

#ifdef CONFIG_COMPAT