/*
* linux/ipc/msg.c
* Copyright (C) 1992 Krishna Balasubramanian
*
* Removed all the remaining kerneld mess
* Catch the -EFAULT stuff properly
* Use GFP_KERNEL for messages as in 1.2
* Fixed up the unchecked user space derefs
* Copyright (C) 1998 Alan Cox & Andi Kleen
*
* /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
*
* mostly rewritten, threaded and wake-one semantics added
* MSGMAX limit removed, sysctl's added
* (c) 1999 Manfred Spraul <manfred@colorfullife.com>
*
* support for audit of ipc object properties and permission changes
* Dustin Kirkland <dustin.kirkland@us.ibm.com>
*
* namespaces support
* OpenVZ, SWsoft Inc.
* Pavel Emelianov <xemul@openvz.org>
*/
#include <linux/capability.h>
#include <linux/msg.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/list.h>
#include <linux/security.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
#include <linux/seq_file.h>
#include <linux/rwsem.h>
#include <linux/nsproxy.h>
#include <linux/ipc_namespace.h>
#include <asm/current.h>
#include <asm/uaccess.h>
#include "util.h"
/*
* one msg_receiver structure for each sleeping receiver:
*/
struct msg_receiver {
struct list_head r_list;
struct task_struct *r_tsk;
int r_mode;
long r_msgtype;
long r_maxsize;
struct msg_msg *volatile r_msg;
};
/* one msg_sender for each sleeping sender */
struct msg_sender {
struct list_head list;
struct task_struct *tsk;
};
#define SEARCH_ANY 1
#define SEARCH_EQUAL 2
#define SEARCH_NOTEQUAL 3
#define SEARCH_LESSEQUAL 4
#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
#define msg_unlock(msq) ipc_unlock(&(msq)->q_perm)
static void freeque(struct ipc_namespace *, struct kern_ipc_perm *);
static int newque(struct ipc_namespace *, struct ipc_params *);
#ifdef CONFIG_PROC_FS
static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
#endif
/*
* Scale msgmni with the available lowmem size: the memory dedicated to msg
* queues should occupy at most 1/MSG_MEM_SCALE of lowmem.
* Also take into account the number of nsproxies created so far.
* This should be done staying within the (MSGMNI , IPCMNI/nr_ipc_ns) range.
*/
void recompute_msgmni(struct ipc_namespace *ns)
{
struct sysinfo i;
unsigned long allowed;
int nb_ns;
si_meminfo(&i);
allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit)
/ MSGMNB;
nb_ns = atomic_read(&nr_ipc_ns);
allowed /= nb_ns;
if (allowed < MSGMNI) {
ns->msg_ctlmni = MSGMNI;
return;
}
if (allowed > IPCMNI / nb_ns) {
ns->msg_ctlmni = IPCMNI / nb_ns;
return;
}
ns->msg_ctlmni = allowed;
}
void msg_init_ns(struct ipc_namespace *ns)
{
ns->msg_ctlmax = MSGMAX;
ns->msg_ctlmnb = MSGMNB;
recompute_msgmni(ns);
atomic_set(&ns->msg_bytes, 0);
atomic_set(&ns->msg_hdrs, 0);
ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
}
#ifdef CONFIG_IPC_NS
void msg_exit_ns(struct ipc_namespace *ns)
{
free_ipcs(ns, &msg_ids(ns), freeque);
idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
}
#endif
void __init msg_init(void)
{
msg_init_ns(&init_ipc_ns);
printk(KERN_INFO "msgmni has been set to %d\n",
init_ipc_ns.msg_ctlmni);
ipc_init_proc_interface("sysvipc/msg",
" key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
IPC_MSG_IDS, sysvipc_msg_proc_show);
}
/*
* msg_lock_(check_) routines are called in the paths where the rw_mutex
* is not held.
*/
static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id)
{
struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id);
if (IS_ERR(ipcp))
return (struct msg_queue *)ipcp;
return container_of(ipcp, struct msg_queue, q_perm);
}
static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns,
int id)
{
struct kern_ipc_perm *ipcp = ipc_lock_check(&msg_ids(ns), id);
if (IS_ERR(ipcp))
return (struct msg_queue *)ipcp;
return container_of(ipcp, struct msg_queue, q_perm);
}
static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
{
ipc_rmid(&msg_ids(ns), &s->q_perm);
}
/**
* newque - Create a new msg queue
* @ns: namespace
* @params: ptr to the structure that contains the key and msgflg
*
* Called with msg_ids.rw_mutex held (writer)
*/
static int newque(struct ipc_namespace *ns, struct ipc_params *params)
{
struct msg_queue *msq;
int id, retval;
key_t key = params->key;
int msgflg = params->flg;
msq = ipc_rcu_alloc(sizeof(*msq));
if (!msq)
return -ENOMEM;
msq->q_perm.mode = msgflg & S_IRWXUGO;
msq->q_perm.key = key;
msq->q_perm.security = NULL;
retval =