SYNOPSIS

struct kern_ipc_perm * ipcctl_pre_down_nolock(struct ipc_namespace * ns, struct ipc_ids * ids, int id, int cmd, struct ipc64_perm * perm, int extra_perm);

ARGUMENTS

ns

ipc namespace

ids

the table of ids where to look for the ipc

id

the id of the ipc to retrieve

cmd

the cmd to check

perm

the permission to set

extra_perm

one extra permission parameter used by msq

DESCRIPTION

This function does some common audit and permissions check for some IPC_XXX cmd and is called from semctl_down, shmctl_down and msgctl_down. It must be called without any lock held and - retrieves the ipc with the given id in the given table. - performs some audit and permission check, depending on the given cmd - returns a pointer to the ipc object or otherwise, the corresponding error.

Call holding the both the rwsem and the rcu read lock.

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