/*
* linux/ipc/util.c
* Copyright (C) 1992 Krishna Balasubramanian
*
* Sep 1997 - Call suser() last after "normal" permission checks so we
* get BSD style process accounting right.
* Occurs in several places in the IPC code.
* Chris Evans, <chris@ferret.lmh.ox.ac.uk>
* Nov 1999 - ipc helper functions, unified SMP locking
* Manfred Spraul <manfred@colorfullife.com>
* Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
* Mingming Cao <cmm@us.ibm.com>
* Mar 2006 - support for audit of ipc object properties
* Dustin Kirkland <dustin.kirkland@us.ibm.com>
* Jun 2006 - namespaces ssupport
* OpenVZ, SWsoft Inc.
* Pavel Emelianov <xemul@openvz.org>
*/
#include <linux/mm.h>
#include <linux/shm.h>
#include <linux/init.h>
#include <linux/msg.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/capability.h>
#include <linux/highuid.h>
#include <linux/security.h>
#include <linux/rcupdate.h>
#include <linux/workqueue.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/audit.h>
#include <linux/nsproxy.h>
#include <linux/rwsem.h>
#include <asm/unistd.h>
#include "util.h"
struct ipc_proc_iface {
const char *path;
const char *header;
int ids;
int (*show)(struct seq_file *, void *);
};
struct ipc_namespace init_ipc_ns = {
.kref = {
.refcount = ATOMIC_INIT(2),
},
};
static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
{
int err;
struct ipc_namespace *ns;
err = -ENOMEM;
ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
if (ns == NULL)
goto err_mem;
err = sem_init_ns(ns);
if (err)
goto err_sem;
err = msg_init_ns(ns);
if (err)
goto err_msg;
err = shm_init_ns(ns);
if (err)
goto err_shm;
kref_init(&ns->kref);
return ns;
err_shm:
msg_exit_ns(ns);
err_msg:
sem_exit_ns(ns);
err_sem:
kfree(ns);
err_mem:
return ERR_PTR(err);
}
struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
{
struct ipc_namespace *new_ns;
BUG_ON(!ns);
get_ipc_ns(ns);
if (!(flags & CLONE_NEWIPC))
return ns;
new_ns = clone_ipc_ns(ns);
put_ipc_ns(ns);
return new_ns;
}
void free_ipc_ns(struct kref *kref)
{
struct ipc_namespace *ns;
ns = container_of(kref, struct ipc_namespace, kref);
sem_exit_ns(ns);
msg_exit_ns(ns);
shm_exit_ns(ns);
kfree(ns);
}
/**
* ipc_init - initialise IPC subsystem
*
* The various system5 IPC resources (semaphores, messages and shared
* memory) are initialised
*/
static int __init ipc_init(void)
{
sem_init();
msg_init();
shm_init();
return 0;
}
__initcall(ipc_init);
/**
* ipc_init_ids - initialise IPC identifiers
* @ids: Identifier set
*
* Set up the sequence range to use for the ipc identifier range (limited
* below IPCMNI) then initialise the ids idr.
*/
void ipc_init_ids(struct ipc_ids *ids)
{
init_rwsem(&ids->rw_mutex);
ids->in_use = 0;
ids->seq = 0;
{
int seq_limit = INT_MAX/SEQ_MULTIPLIER;
if(seq_limit > USHRT_MAX)
ids->seq_max = USHRT_MAX;
else
ids->seq_max = seq_limit;
}
idr_init(&ids->ipcs_idr);
}
#ifdef CONFIG_PROC_FS
static const struct file_operations sysvipc_proc_fops;
/**
* ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface.
* @path: Path in procfs
* @header: Banner to be printed at the beginning of the file.
* @ids: ipc id table to iterate.
* @show: show routine.
*/
void __init ipc_init_proc_interface(const char *path, const char *header,
int ids, int (*show)(struct seq_file *, void *))
{
struct proc_dir_entry *pde;
struct ipc_proc_iface *iface;
iface = kmalloc(sizeof(*iface), GFP_KERNEL);
if (!iface)
return;
iface->path = path;
iface->header = header;
iface->ids = ids;
iface->show = show;
pde = create_proc_entry(path,
S_IRUGO, /* world readable */
NULL /* parent dir */);
if (pde) {
pde->data = iface;
pde->proc_fops = &sysvipc_proc_fops;
} else {
kfree(iface);
}
}
#endif
/**
* ipc_findkey - find a key in an ipc identifier set
* @ids: Identifier set
* @key: The key to find
*
* Requires ipc_ids.rw_mutex locked.
* Returns the LOCKED pointer to the ipc structure if found or NULL
* if not.
* If key is found ipc points to the owning ipc structure
*/
static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
{
struct kern_ipc_perm *ipc;
int next_id;
int total;
for (total = 0, next_id = 0; total < ids->in_use