blob: 996feb81924816e7a8608624dd92e7bb7d09e132 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/ipc/msg.c
Ingo Molnar5a06a362006-07-30 03:04:11 -07003 * Copyright (C) 1992 Krishna Balasubramanian
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 *
5 * Removed all the remaining kerneld mess
6 * Catch the -EFAULT stuff properly
7 * Use GFP_KERNEL for messages as in 1.2
8 * Fixed up the unchecked user space derefs
9 * Copyright (C) 1998 Alan Cox & Andi Kleen
10 *
11 * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
12 *
13 * mostly rewritten, threaded and wake-one semantics added
14 * MSGMAX limit removed, sysctl's added
Christian Kujau624dffc2006-01-15 02:43:54 +010015 * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
Steve Grubb073115d2006-04-02 17:07:33 -040016 *
17 * support for audit of ipc object properties and permission changes
18 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
Kirill Korotaev1e786932006-10-02 02:18:21 -070019 *
20 * namespaces support
21 * OpenVZ, SWsoft Inc.
22 * Pavel Emelianov <xemul@openvz.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023 */
24
Randy.Dunlapc59ede72006-01-11 12:17:46 -080025#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/msg.h>
27#include <linux/spinlock.h>
28#include <linux/init.h>
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -070029#include <linux/mm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <linux/proc_fs.h>
31#include <linux/list.h>
32#include <linux/security.h>
33#include <linux/sched.h>
34#include <linux/syscalls.h>
35#include <linux/audit.h>
Mike Waychison19b49462005-09-06 15:17:10 -070036#include <linux/seq_file.h>
Nadia Derbey3e148c72007-10-18 23:40:54 -070037#include <linux/rwsem.h>
Kirill Korotaev1e786932006-10-02 02:18:21 -070038#include <linux/nsproxy.h>
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080039#include <linux/ipc_namespace.h>
Ingo Molnar5f921ae2006-03-26 01:37:17 -080040
Linus Torvalds1da177e2005-04-16 15:20:36 -070041#include <asm/current.h>
42#include <asm/uaccess.h>
43#include "util.h"
44
Ingo Molnar5a06a362006-07-30 03:04:11 -070045/*
46 * one msg_receiver structure for each sleeping receiver:
47 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070048struct msg_receiver {
Ingo Molnar5a06a362006-07-30 03:04:11 -070049 struct list_head r_list;
50 struct task_struct *r_tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -070051
Ingo Molnar5a06a362006-07-30 03:04:11 -070052 int r_mode;
53 long r_msgtype;
54 long r_maxsize;
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
Linus Torvalds80491eb2006-11-04 09:55:00 -080056 struct msg_msg *volatile r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057};
58
59/* one msg_sender for each sleeping sender */
60struct msg_sender {
Ingo Molnar5a06a362006-07-30 03:04:11 -070061 struct list_head list;
62 struct task_struct *tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -070063};
64
65#define SEARCH_ANY 1
66#define SEARCH_EQUAL 2
67#define SEARCH_NOTEQUAL 3
68#define SEARCH_LESSEQUAL 4
Peter Hurley8ac6ed52013-04-30 19:14:54 -070069#define SEARCH_NUMBER 5
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080071#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
Kirill Korotaev1e786932006-10-02 02:18:21 -070072
Ingo Molnar5a06a362006-07-30 03:04:11 -070073#define msg_unlock(msq) ipc_unlock(&(msq)->q_perm)
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
Pierre Peiffer01b8b072008-02-08 04:18:57 -080075static void freeque(struct ipc_namespace *, struct kern_ipc_perm *);
Nadia Derbey7748dbf2007-10-18 23:40:49 -070076static int newque(struct ipc_namespace *, struct ipc_params *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -070078static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079#endif
80
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -070081/*
82 * Scale msgmni with the available lowmem size: the memory dedicated to msg
83 * queues should occupy at most 1/MSG_MEM_SCALE of lowmem.
Nadia Derbey4d89dc62008-04-29 01:00:40 -070084 * Also take into account the number of nsproxies created so far.
85 * This should be done staying within the (MSGMNI , IPCMNI/nr_ipc_ns) range.
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -070086 */
Nadia Derbeyb6b337a2008-04-29 01:00:42 -070087void recompute_msgmni(struct ipc_namespace *ns)
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -070088{
89 struct sysinfo i;
90 unsigned long allowed;
Nadia Derbey4d89dc62008-04-29 01:00:40 -070091 int nb_ns;
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -070092
93 si_meminfo(&i);
94 allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit)
95 / MSGMNB;
Nadia Derbey4d89dc62008-04-29 01:00:40 -070096 nb_ns = atomic_read(&nr_ipc_ns);
97 allowed /= nb_ns;
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -070098
99 if (allowed < MSGMNI) {
100 ns->msg_ctlmni = MSGMNI;
Nadia Derbeydfcceb22008-06-05 22:46:38 -0700101 return;
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -0700102 }
103
Nadia Derbey4d89dc62008-04-29 01:00:40 -0700104 if (allowed > IPCMNI / nb_ns) {
105 ns->msg_ctlmni = IPCMNI / nb_ns;
Nadia Derbeydfcceb22008-06-05 22:46:38 -0700106 return;
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -0700107 }
108
109 ns->msg_ctlmni = allowed;
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -0700110}
111
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800112void msg_init_ns(struct ipc_namespace *ns)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113{
Kirill Korotaev1e786932006-10-02 02:18:21 -0700114 ns->msg_ctlmax = MSGMAX;
115 ns->msg_ctlmnb = MSGMNB;
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -0700116
117 recompute_msgmni(ns);
118
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700119 atomic_set(&ns->msg_bytes, 0);
120 atomic_set(&ns->msg_hdrs, 0);
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800121 ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122}
123
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800124#ifdef CONFIG_IPC_NS
Kirill Korotaev1e786932006-10-02 02:18:21 -0700125void msg_exit_ns(struct ipc_namespace *ns)
126{
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800127 free_ipcs(ns, &msg_ids(ns), freeque);
Serge E. Hallyn7d6feeb2009-12-15 16:47:27 -0800128 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
Kirill Korotaev1e786932006-10-02 02:18:21 -0700129}
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800130#endif
Kirill Korotaev1e786932006-10-02 02:18:21 -0700131
132void __init msg_init(void)
133{
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800134 msg_init_ns(&init_ipc_ns);
Nadia Derbeydfcceb22008-06-05 22:46:38 -0700135
136 printk(KERN_INFO "msgmni has been set to %d\n",
137 init_ipc_ns.msg_ctlmni);
138
Kirill Korotaev1e786932006-10-02 02:18:21 -0700139 ipc_init_proc_interface("sysvipc/msg",
140 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
141 IPC_MSG_IDS, sysvipc_msg_proc_show);
142}
143
Nadia Derbey3e148c72007-10-18 23:40:54 -0700144/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700145 * msg_lock_(check_) routines are called in the paths where the rw_mutex
146 * is not held.
147 */
Nadia Derbey023a5352007-10-18 23:40:51 -0700148static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id)
149{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700150 struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id);
151
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800152 if (IS_ERR(ipcp))
153 return (struct msg_queue *)ipcp;
154
Nadia Derbey03f02c72007-10-18 23:40:51 -0700155 return container_of(ipcp, struct msg_queue, q_perm);
Nadia Derbey023a5352007-10-18 23:40:51 -0700156}
157
158static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns,
159 int id)
160{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700161 struct kern_ipc_perm *ipcp = ipc_lock_check(&msg_ids(ns), id);
162
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800163 if (IS_ERR(ipcp))
164 return (struct msg_queue *)ipcp;
165
Nadia Derbey03f02c72007-10-18 23:40:51 -0700166 return container_of(ipcp, struct msg_queue, q_perm);
Nadia Derbey023a5352007-10-18 23:40:51 -0700167}
168
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700169static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
170{
171 ipc_rmid(&msg_ids(ns), &s->q_perm);
172}
173
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700174/**
175 * newque - Create a new msg queue
176 * @ns: namespace
177 * @params: ptr to the structure that contains the key and msgflg
178 *
Nadia Derbey3e148c72007-10-18 23:40:54 -0700179 * Called with msg_ids.rw_mutex held (writer)
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700180 */
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700181static int newque(struct ipc_namespace *ns, struct ipc_params *params)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 struct msg_queue *msq;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700184 int id, retval;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700185 key_t key = params->key;
186 int msgflg = params->flg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187
Ingo Molnar5a06a362006-07-30 03:04:11 -0700188 msq = ipc_rcu_alloc(sizeof(*msq));
189 if (!msq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 return -ENOMEM;
191
Ingo Molnar5a06a362006-07-30 03:04:11 -0700192 msq->q_perm.mode = msgflg & S_IRWXUGO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 msq->q_perm.key = key;
194
195 msq->q_perm.security = NULL;
196 retval = security_msg_queue_alloc(msq);
197 if (retval) {
198 ipc_rcu_putref(msq);
199 return retval;
200 }
201
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700202 /* ipc_addid() locks msq upon success. */
Kirill Korotaev1e786932006-10-02 02:18:21 -0700203 id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700204 if (id < 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 security_msg_queue_free(msq);
206 ipc_rcu_putref(msq);
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700207 return id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 }
209
210 msq->q_stime = msq->q_rtime = 0;
211 msq->q_ctime = get_seconds();
212 msq->q_cbytes = msq->q_qnum = 0;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700213 msq->q_qbytes = ns->msg_ctlmnb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 msq->q_lspid = msq->q_lrpid = 0;
215 INIT_LIST_HEAD(&msq->q_messages);
216 INIT_LIST_HEAD(&msq->q_receivers);
217 INIT_LIST_HEAD(&msq->q_senders);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700218
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700219 spin_unlock(&msq->q_perm.lock);
220 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700222 return msq->q_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223}
224
Ingo Molnar5a06a362006-07-30 03:04:11 -0700225static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700227 mss->tsk = current;
228 current->state = TASK_INTERRUPTIBLE;
229 list_add_tail(&mss->list, &msq->q_senders);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230}
231
Ingo Molnar5a06a362006-07-30 03:04:11 -0700232static inline void ss_del(struct msg_sender *mss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700234 if (mss->list.next != NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 list_del(&mss->list);
236}
237
Ingo Molnar5a06a362006-07-30 03:04:11 -0700238static void ss_wakeup(struct list_head *h, int kill)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239{
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700240 struct msg_sender *mss, *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700242 list_for_each_entry_safe(mss, t, h, list) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700243 if (kill)
244 mss->list.next = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 wake_up_process(mss->tsk);
246 }
247}
248
Ingo Molnar5a06a362006-07-30 03:04:11 -0700249static void expunge_all(struct msg_queue *msq, int res)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250{
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700251 struct msg_receiver *msr, *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700253 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 msr->r_msg = NULL;
255 wake_up_process(msr->r_tsk);
256 smp_mb();
257 msr->r_msg = ERR_PTR(res);
258 }
259}
Ingo Molnar5a06a362006-07-30 03:04:11 -0700260
261/*
262 * freeque() wakes up waiters on the sender and receiver waiting queue,
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700263 * removes the message queue from message queue ID IDR, and cleans up all the
264 * messages associated with this queue.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 *
Nadia Derbey3e148c72007-10-18 23:40:54 -0700266 * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held
267 * before freeque() is called. msg_ids.rw_mutex remains locked on exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 */
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800269static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270{
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700271 struct msg_msg *msg, *t;
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800272 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273
Ingo Molnar5a06a362006-07-30 03:04:11 -0700274 expunge_all(msq, -EIDRM);
275 ss_wakeup(&msq->q_senders, 1);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700276 msg_rmid(ns, msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 msg_unlock(msq);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700278
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700279 list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700280 atomic_dec(&ns->msg_hdrs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 free_msg(msg);
282 }
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700283 atomic_sub(msq->q_cbytes, &ns->msg_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 security_msg_queue_free(msq);
285 ipc_rcu_putref(msq);
286}
287
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700288/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700289 * Called with msg_ids.rw_mutex and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700290 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700291static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700292{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700293 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
294
295 return security_msg_queue_associate(msq, msgflg);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700296}
297
Heiko Carstense48fbb62009-01-14 14:14:26 +0100298SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299{
Kirill Korotaev1e786932006-10-02 02:18:21 -0700300 struct ipc_namespace *ns;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700301 struct ipc_ops msg_ops;
302 struct ipc_params msg_params;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700303
304 ns = current->nsproxy->ipc_ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700305
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700306 msg_ops.getnew = newque;
307 msg_ops.associate = msg_security;
308 msg_ops.more_checks = NULL;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700309
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700310 msg_params.key = key;
311 msg_params.flg = msgflg;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700312
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700313 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314}
315
Ingo Molnar5a06a362006-07-30 03:04:11 -0700316static inline unsigned long
317copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318{
319 switch(version) {
320 case IPC_64:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700321 return copy_to_user(buf, in, sizeof(*in));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 case IPC_OLD:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700323 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 struct msqid_ds out;
325
Ingo Molnar5a06a362006-07-30 03:04:11 -0700326 memset(&out, 0, sizeof(out));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
328 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
329
330 out.msg_stime = in->msg_stime;
331 out.msg_rtime = in->msg_rtime;
332 out.msg_ctime = in->msg_ctime;
333
Alexey Dobriyan4be929b2010-05-24 14:33:03 -0700334 if (in->msg_cbytes > USHRT_MAX)
335 out.msg_cbytes = USHRT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 else
337 out.msg_cbytes = in->msg_cbytes;
338 out.msg_lcbytes = in->msg_cbytes;
339
Alexey Dobriyan4be929b2010-05-24 14:33:03 -0700340 if (in->msg_qnum > USHRT_MAX)
341 out.msg_qnum = USHRT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 else
343 out.msg_qnum = in->msg_qnum;
344
Alexey Dobriyan4be929b2010-05-24 14:33:03 -0700345 if (in->msg_qbytes > USHRT_MAX)
346 out.msg_qbytes = USHRT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 else
348 out.msg_qbytes = in->msg_qbytes;
349 out.msg_lqbytes = in->msg_qbytes;
350
351 out.msg_lspid = in->msg_lspid;
352 out.msg_lrpid = in->msg_lrpid;
353
Ingo Molnar5a06a362006-07-30 03:04:11 -0700354 return copy_to_user(buf, &out, sizeof(out));
355 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 default:
357 return -EINVAL;
358 }
359}
360
Ingo Molnar5a06a362006-07-30 03:04:11 -0700361static inline unsigned long
Pierre Peiffer016d7132008-04-29 01:00:50 -0700362copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363{
364 switch(version) {
365 case IPC_64:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700366 if (copy_from_user(out, buf, sizeof(*out)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 case IPC_OLD:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700370 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 struct msqid_ds tbuf_old;
372
Ingo Molnar5a06a362006-07-30 03:04:11 -0700373 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 return -EFAULT;
375
Pierre Peiffer016d7132008-04-29 01:00:50 -0700376 out->msg_perm.uid = tbuf_old.msg_perm.uid;
377 out->msg_perm.gid = tbuf_old.msg_perm.gid;
378 out->msg_perm.mode = tbuf_old.msg_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379
Ingo Molnar5a06a362006-07-30 03:04:11 -0700380 if (tbuf_old.msg_qbytes == 0)
Pierre Peiffer016d7132008-04-29 01:00:50 -0700381 out->msg_qbytes = tbuf_old.msg_lqbytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 else
Pierre Peiffer016d7132008-04-29 01:00:50 -0700383 out->msg_qbytes = tbuf_old.msg_qbytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384
385 return 0;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700386 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 default:
388 return -EINVAL;
389 }
390}
391
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700392/*
393 * This function handles some msgctl commands which require the rw_mutex
394 * to be held in write mode.
395 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
396 */
397static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
398 struct msqid_ds __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 struct kern_ipc_perm *ipcp;
Felipe Contrerasf1970c42009-10-19 01:54:29 +0300401 struct msqid64_ds uninitialized_var(msqid64);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700402 struct msg_queue *msq;
403 int err;
404
405 if (cmd == IPC_SET) {
Pierre Peiffer016d7132008-04-29 01:00:50 -0700406 if (copy_msqid_from_user(&msqid64, buf, version))
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700407 return -EFAULT;
408 }
409
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700410 ipcp = ipcctl_pre_down(ns, &msg_ids(ns), msqid, cmd,
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700411 &msqid64.msg_perm, msqid64.msg_qbytes);
412 if (IS_ERR(ipcp))
413 return PTR_ERR(ipcp);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700414
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700415 msq = container_of(ipcp, struct msg_queue, q_perm);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700416
417 err = security_msg_queue_msgctl(msq, cmd);
418 if (err)
419 goto out_unlock;
420
421 switch (cmd) {
422 case IPC_RMID:
423 freeque(ns, ipcp);
424 goto out_up;
425 case IPC_SET:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700426 if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700427 !capable(CAP_SYS_RESOURCE)) {
428 err = -EPERM;
429 goto out_unlock;
430 }
431
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800432 err = ipc_update_perm(&msqid64.msg_perm, ipcp);
433 if (err)
434 goto out_unlock;
435
Pierre Peiffer016d7132008-04-29 01:00:50 -0700436 msq->q_qbytes = msqid64.msg_qbytes;
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700437
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700438 msq->q_ctime = get_seconds();
439 /* sleeping receivers might be excluded by
440 * stricter permissions.
441 */
442 expunge_all(msq, -EAGAIN);
443 /* sleeping senders might be able to send
444 * due to a larger queue size.
445 */
446 ss_wakeup(&msq->q_senders, 0);
447 break;
448 default:
449 err = -EINVAL;
450 }
451out_unlock:
452 msg_unlock(msq);
453out_up:
454 up_write(&msg_ids(ns).rw_mutex);
455 return err;
456}
457
Heiko Carstense48fbb62009-01-14 14:14:26 +0100458SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700459{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700460 struct msg_queue *msq;
461 int err, version;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700462 struct ipc_namespace *ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700463
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 if (msqid < 0 || cmd < 0)
465 return -EINVAL;
466
467 version = ipc_parse_version(&cmd);
Kirill Korotaev1e786932006-10-02 02:18:21 -0700468 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469
470 switch (cmd) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700471 case IPC_INFO:
472 case MSG_INFO:
473 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 struct msginfo msginfo;
475 int max_id;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700476
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 if (!buf)
478 return -EFAULT;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700479 /*
480 * We must not return kernel stack data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 * due to padding, it's not enough
482 * to set all member fields.
483 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 err = security_msg_queue_msgctl(NULL, cmd);
485 if (err)
486 return err;
487
Ingo Molnar5a06a362006-07-30 03:04:11 -0700488 memset(&msginfo, 0, sizeof(msginfo));
Kirill Korotaev1e786932006-10-02 02:18:21 -0700489 msginfo.msgmni = ns->msg_ctlmni;
490 msginfo.msgmax = ns->msg_ctlmax;
491 msginfo.msgmnb = ns->msg_ctlmnb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 msginfo.msgssz = MSGSSZ;
493 msginfo.msgseg = MSGSEG;
Nadia Derbey3e148c72007-10-18 23:40:54 -0700494 down_read(&msg_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 if (cmd == MSG_INFO) {
Kirill Korotaev1e786932006-10-02 02:18:21 -0700496 msginfo.msgpool = msg_ids(ns).in_use;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700497 msginfo.msgmap = atomic_read(&ns->msg_hdrs);
498 msginfo.msgtql = atomic_read(&ns->msg_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 } else {
500 msginfo.msgmap = MSGMAP;
501 msginfo.msgpool = MSGPOOL;
502 msginfo.msgtql = MSGTQL;
503 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700504 max_id = ipc_get_maxid(&msg_ids(ns));
Nadia Derbey3e148c72007-10-18 23:40:54 -0700505 up_read(&msg_ids(ns).rw_mutex);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700506 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 return -EFAULT;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700508 return (max_id < 0) ? 0 : max_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700510 case MSG_STAT: /* msqid is an index rather than a msg queue id */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 case IPC_STAT:
512 {
513 struct msqid64_ds tbuf;
514 int success_return;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700515
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 if (!buf)
517 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518
Ingo Molnar5a06a362006-07-30 03:04:11 -0700519 if (cmd == MSG_STAT) {
Nadia Derbey023a5352007-10-18 23:40:51 -0700520 msq = msg_lock(ns, msqid);
521 if (IS_ERR(msq))
522 return PTR_ERR(msq);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700523 success_return = msq->q_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 } else {
Nadia Derbey023a5352007-10-18 23:40:51 -0700525 msq = msg_lock_check(ns, msqid);
526 if (IS_ERR(msq))
527 return PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 success_return = 0;
529 }
530 err = -EACCES;
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700531 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 goto out_unlock;
533
534 err = security_msg_queue_msgctl(msq, cmd);
535 if (err)
536 goto out_unlock;
537
Nadia Derbey023a5352007-10-18 23:40:51 -0700538 memset(&tbuf, 0, sizeof(tbuf));
539
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
541 tbuf.msg_stime = msq->q_stime;
542 tbuf.msg_rtime = msq->q_rtime;
543 tbuf.msg_ctime = msq->q_ctime;
544 tbuf.msg_cbytes = msq->q_cbytes;
545 tbuf.msg_qnum = msq->q_qnum;
546 tbuf.msg_qbytes = msq->q_qbytes;
547 tbuf.msg_lspid = msq->q_lspid;
548 tbuf.msg_lrpid = msq->q_lrpid;
549 msg_unlock(msq);
550 if (copy_msqid_to_user(buf, &tbuf, version))
551 return -EFAULT;
552 return success_return;
553 }
554 case IPC_SET:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 case IPC_RMID:
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700556 err = msgctl_down(ns, msqid, cmd, buf, version);
557 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 default:
559 return -EINVAL;
560 }
561
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562out_unlock:
563 msg_unlock(msq);
564 return err;
565}
566
Ingo Molnar5a06a362006-07-30 03:04:11 -0700567static int testmsg(struct msg_msg *msg, long type, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568{
569 switch(mode)
570 {
571 case SEARCH_ANY:
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700572 case SEARCH_NUMBER:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 return 1;
574 case SEARCH_LESSEQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700575 if (msg->m_type <=type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 return 1;
577 break;
578 case SEARCH_EQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700579 if (msg->m_type == type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580 return 1;
581 break;
582 case SEARCH_NOTEQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700583 if (msg->m_type != type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 return 1;
585 break;
586 }
587 return 0;
588}
589
Ingo Molnar5a06a362006-07-30 03:04:11 -0700590static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591{
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700592 struct msg_receiver *msr, *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593
Nikola Pajkovsky41239fe2013-04-30 19:15:49 -0700594 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700595 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
596 !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
597 msr->r_msgtype, msr->r_mode)) {
598
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 list_del(&msr->r_list);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700600 if (msr->r_maxsize < msg->m_ts) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 msr->r_msg = NULL;
602 wake_up_process(msr->r_tsk);
603 smp_mb();
604 msr->r_msg = ERR_PTR(-E2BIG);
605 } else {
606 msr->r_msg = NULL;
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700607 msq->q_lrpid = task_pid_vnr(msr->r_tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 msq->q_rtime = get_seconds();
609 wake_up_process(msr->r_tsk);
610 smp_mb();
611 msr->r_msg = msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700612
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 return 1;
614 }
615 }
616 }
617 return 0;
618}
619
suzuki651971c2006-12-06 20:37:48 -0800620long do_msgsnd(int msqid, long mtype, void __user *mtext,
621 size_t msgsz, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622{
623 struct msg_queue *msq;
624 struct msg_msg *msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 int err;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700626 struct ipc_namespace *ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700627
Kirill Korotaev1e786932006-10-02 02:18:21 -0700628 ns = current->nsproxy->ipc_ns;
629
630 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 if (mtype < 1)
633 return -EINVAL;
634
suzuki651971c2006-12-06 20:37:48 -0800635 msg = load_msg(mtext, msgsz);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700636 if (IS_ERR(msg))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637 return PTR_ERR(msg);
638
639 msg->m_type = mtype;
640 msg->m_ts = msgsz;
641
Nadia Derbey023a5352007-10-18 23:40:51 -0700642 msq = msg_lock_check(ns, msqid);
643 if (IS_ERR(msq)) {
644 err = PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 goto out_free;
Nadia Derbey023a5352007-10-18 23:40:51 -0700646 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647
648 for (;;) {
649 struct msg_sender s;
650
Ingo Molnar5a06a362006-07-30 03:04:11 -0700651 err = -EACCES;
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700652 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 goto out_unlock_free;
654
655 err = security_msg_queue_msgsnd(msq, msg, msgflg);
656 if (err)
657 goto out_unlock_free;
658
Ingo Molnar5a06a362006-07-30 03:04:11 -0700659 if (msgsz + msq->q_cbytes <= msq->q_qbytes &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 1 + msq->q_qnum <= msq->q_qbytes) {
661 break;
662 }
663
664 /* queue full, wait: */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700665 if (msgflg & IPC_NOWAIT) {
666 err = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 goto out_unlock_free;
668 }
669 ss_add(msq, &s);
Rik van Riel6062a8d2013-04-30 19:15:44 -0700670
671 if (!ipc_rcu_getref(msq)) {
672 err = -EIDRM;
673 goto out_unlock_free;
674 }
675
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 msg_unlock(msq);
677 schedule();
678
679 ipc_lock_by_ptr(&msq->q_perm);
680 ipc_rcu_putref(msq);
681 if (msq->q_perm.deleted) {
682 err = -EIDRM;
683 goto out_unlock_free;
684 }
685 ss_del(&s);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700686
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 if (signal_pending(current)) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700688 err = -ERESTARTNOHAND;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 goto out_unlock_free;
690 }
691 }
692
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700693 msq->q_lspid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 msq->q_stime = get_seconds();
695
Ingo Molnar5a06a362006-07-30 03:04:11 -0700696 if (!pipelined_send(msq, msg)) {
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300697 /* no one is waiting for this message, enqueue it */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700698 list_add_tail(&msg->m_list, &msq->q_messages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 msq->q_cbytes += msgsz;
700 msq->q_qnum++;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700701 atomic_add(msgsz, &ns->msg_bytes);
702 atomic_inc(&ns->msg_hdrs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700704
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 err = 0;
706 msg = NULL;
707
708out_unlock_free:
709 msg_unlock(msq);
710out_free:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700711 if (msg != NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 free_msg(msg);
713 return err;
714}
715
Heiko Carstense48fbb62009-01-14 14:14:26 +0100716SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
717 int, msgflg)
suzuki651971c2006-12-06 20:37:48 -0800718{
719 long mtype;
720
721 if (get_user(mtype, &msgp->mtype))
722 return -EFAULT;
723 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
724}
725
Ingo Molnar5a06a362006-07-30 03:04:11 -0700726static inline int convert_mode(long *msgtyp, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727{
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700728 if (msgflg & MSG_COPY)
729 return SEARCH_NUMBER;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700730 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 * find message of correct type.
732 * msgtyp = 0 => get first.
733 * msgtyp > 0 => get first message of matching type.
Ingo Molnar5a06a362006-07-30 03:04:11 -0700734 * msgtyp < 0 => get message with least type must be < abs(msgtype).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700736 if (*msgtyp == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737 return SEARCH_ANY;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700738 if (*msgtyp < 0) {
739 *msgtyp = -*msgtyp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 return SEARCH_LESSEQUAL;
741 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700742 if (msgflg & MSG_EXCEPT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 return SEARCH_NOTEQUAL;
744 return SEARCH_EQUAL;
745}
746
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800747static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
748{
749 struct msgbuf __user *msgp = dest;
750 size_t msgsz;
751
752 if (put_user(msg->m_type, &msgp->mtype))
753 return -EFAULT;
754
755 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
756 if (store_msg(msgp->mtext, msg, msgsz))
757 return -EFAULT;
758 return msgsz;
759}
760
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800761#ifdef CONFIG_CHECKPOINT_RESTORE
Stanislav Kinsbursky3fcfe782013-01-04 15:35:03 -0800762/*
763 * This function creates new kernel message structure, large enough to store
764 * bufsz message bytes.
765 */
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700766static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800767{
768 struct msg_msg *copy;
769
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800770 /*
771 * Create dummy message to copy real message to.
772 */
773 copy = load_msg(buf, bufsz);
774 if (!IS_ERR(copy))
775 copy->m_ts = bufsz;
776 return copy;
777}
778
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800779static inline void free_copy(struct msg_msg *copy)
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800780{
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800781 if (copy)
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800782 free_msg(copy);
783}
784#else
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700785static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
Stanislav Kinsburskyb30efe22013-01-04 15:35:00 -0800786{
787 return ERR_PTR(-ENOSYS);
788}
789
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800790static inline void free_copy(struct msg_msg *copy)
791{
792}
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800793#endif
794
Peter Hurleydaaf74c2013-04-30 19:15:04 -0700795static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
796{
797 struct msg_msg *msg;
798 long count = 0;
799
800 list_for_each_entry(msg, &msq->q_messages, m_list) {
801 if (testmsg(msg, *msgtyp, mode) &&
802 !security_msg_queue_msgrcv(msq, msg, current,
803 *msgtyp, mode)) {
804 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
805 *msgtyp = msg->m_type - 1;
806 } else if (mode == SEARCH_NUMBER) {
807 if (*msgtyp == count)
808 return msg;
809 } else
810 return msg;
811 count++;
812 }
813 }
814
815 return ERR_PTR(-EAGAIN);
816}
817
818
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800819long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
820 int msgflg,
821 long (*msg_handler)(void __user *, struct msg_msg *, size_t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822{
823 struct msg_queue *msq;
824 struct msg_msg *msg;
825 int mode;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700826 struct ipc_namespace *ns;
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800827 struct msg_msg *copy = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828
Peter Hurley88b9e452013-03-08 12:43:27 -0800829 ns = current->nsproxy->ipc_ns;
830
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800831 if (msqid < 0 || (long) bufsz < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 return -EINVAL;
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800833 if (msgflg & MSG_COPY) {
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700834 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800835 if (IS_ERR(copy))
836 return PTR_ERR(copy);
837 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700838 mode = convert_mode(&msgtyp, msgflg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839
Nadia Derbey023a5352007-10-18 23:40:51 -0700840 msq = msg_lock_check(ns, msqid);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800841 if (IS_ERR(msq)) {
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800842 free_copy(copy);
Nadia Derbey023a5352007-10-18 23:40:51 -0700843 return PTR_ERR(msq);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800844 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845
846 for (;;) {
847 struct msg_receiver msr_d;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848
849 msg = ERR_PTR(-EACCES);
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700850 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 goto out_unlock;
852
Peter Hurleydaaf74c2013-04-30 19:15:04 -0700853 msg = find_msg(msq, &msgtyp, mode);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700854
Ingo Molnar5a06a362006-07-30 03:04:11 -0700855 if (!IS_ERR(msg)) {
856 /*
857 * Found a suitable message.
858 * Unlink it from the queue.
859 */
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800860 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 msg = ERR_PTR(-E2BIG);
862 goto out_unlock;
863 }
Stanislav Kinsbursky3fcfe782013-01-04 15:35:03 -0800864 /*
865 * If we are copying, then do not unlink message and do
866 * not update queue parameters.
867 */
Peter Hurley852028a2013-04-30 19:14:48 -0700868 if (msgflg & MSG_COPY) {
869 msg = copy_msg(msg, copy);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800870 goto out_unlock;
Peter Hurley852028a2013-04-30 19:14:48 -0700871 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 list_del(&msg->m_list);
873 msq->q_qnum--;
874 msq->q_rtime = get_seconds();
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700875 msq->q_lrpid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 msq->q_cbytes -= msg->m_ts;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700877 atomic_sub(msg->m_ts, &ns->msg_bytes);
878 atomic_dec(&ns->msg_hdrs);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700879 ss_wakeup(&msq->q_senders, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 msg_unlock(msq);
881 break;
882 }
883 /* No message waiting. Wait for a message */
884 if (msgflg & IPC_NOWAIT) {
885 msg = ERR_PTR(-ENOMSG);
886 goto out_unlock;
887 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700888 list_add_tail(&msr_d.r_list, &msq->q_receivers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 msr_d.r_tsk = current;
890 msr_d.r_msgtype = msgtyp;
891 msr_d.r_mode = mode;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700892 if (msgflg & MSG_NOERROR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 msr_d.r_maxsize = INT_MAX;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700894 else
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800895 msr_d.r_maxsize = bufsz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 msr_d.r_msg = ERR_PTR(-EAGAIN);
897 current->state = TASK_INTERRUPTIBLE;
898 msg_unlock(msq);
899
900 schedule();
901
902 /* Lockless receive, part 1:
903 * Disable preemption. We don't hold a reference to the queue
904 * and getting a reference would defeat the idea of a lockless
905 * operation, thus the code relies on rcu to guarantee the
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300906 * existence of msq:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
908 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
909 * rcu_read_lock() prevents preemption between reading r_msg
910 * and the spin_lock() inside ipc_lock_by_ptr().
911 */
912 rcu_read_lock();
913
914 /* Lockless receive, part 2:
915 * Wait until pipelined_send or expunge_all are outside of
916 * wake_up_process(). There is a race with exit(), see
917 * ipc/mqueue.c for the details.
918 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700919 msg = (struct msg_msg*)msr_d.r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 while (msg == NULL) {
921 cpu_relax();
Ingo Molnar5a06a362006-07-30 03:04:11 -0700922 msg = (struct msg_msg *)msr_d.r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 }
924
925 /* Lockless receive, part 3:
926 * If there is a message or an error then accept it without
927 * locking.
928 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700929 if (msg != ERR_PTR(-EAGAIN)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 rcu_read_unlock();
931 break;
932 }
933
934 /* Lockless receive, part 3:
935 * Acquire the queue spinlock.
936 */
937 ipc_lock_by_ptr(&msq->q_perm);
938 rcu_read_unlock();
939
940 /* Lockless receive, part 4:
941 * Repeat test after acquiring the spinlock.
942 */
943 msg = (struct msg_msg*)msr_d.r_msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700944 if (msg != ERR_PTR(-EAGAIN))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 goto out_unlock;
946
947 list_del(&msr_d.r_list);
948 if (signal_pending(current)) {
949 msg = ERR_PTR(-ERESTARTNOHAND);
950out_unlock:
951 msg_unlock(msq);
952 break;
953 }
954 }
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800955 if (IS_ERR(msg)) {
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800956 free_copy(copy);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700957 return PTR_ERR(msg);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800958 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800960 bufsz = msg_handler(buf, msg, bufsz);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 free_msg(msg);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700962
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800963 return bufsz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964}
965
Heiko Carstense48fbb62009-01-14 14:14:26 +0100966SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
967 long, msgtyp, int, msgflg)
suzuki651971c2006-12-06 20:37:48 -0800968{
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800969 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
suzuki651971c2006-12-06 20:37:48 -0800970}
971
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -0700973static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974{
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800975 struct user_namespace *user_ns = seq_user_ns(s);
Mike Waychison19b49462005-09-06 15:17:10 -0700976 struct msg_queue *msq = it;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977
Mike Waychison19b49462005-09-06 15:17:10 -0700978 return seq_printf(s,
Ingo Molnar5a06a362006-07-30 03:04:11 -0700979 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
980 msq->q_perm.key,
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700981 msq->q_perm.id,
Ingo Molnar5a06a362006-07-30 03:04:11 -0700982 msq->q_perm.mode,
983 msq->q_cbytes,
984 msq->q_qnum,
985 msq->q_lspid,
986 msq->q_lrpid,
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800987 from_kuid_munged(user_ns, msq->q_perm.uid),
988 from_kgid_munged(user_ns, msq->q_perm.gid),
989 from_kuid_munged(user_ns, msq->q_perm.cuid),
990 from_kgid_munged(user_ns, msq->q_perm.cgid),
Ingo Molnar5a06a362006-07-30 03:04:11 -0700991 msq->q_stime,
992 msq->q_rtime,
993 msq->q_ctime);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994}
995#endif