blob: 09a1f41e6595f9198f1a25d55f5d5c00f1f154b9 [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
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700202 /*
203 * ipc_addid() locks msq
204 */
Kirill Korotaev1e786932006-10-02 02:18:21 -0700205 id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700206 if (id < 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 security_msg_queue_free(msq);
208 ipc_rcu_putref(msq);
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700209 return id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 }
211
212 msq->q_stime = msq->q_rtime = 0;
213 msq->q_ctime = get_seconds();
214 msq->q_cbytes = msq->q_qnum = 0;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700215 msq->q_qbytes = ns->msg_ctlmnb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 msq->q_lspid = msq->q_lrpid = 0;
217 INIT_LIST_HEAD(&msq->q_messages);
218 INIT_LIST_HEAD(&msq->q_receivers);
219 INIT_LIST_HEAD(&msq->q_senders);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700220
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 msg_unlock(msq);
222
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700223 return msq->q_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224}
225
Ingo Molnar5a06a362006-07-30 03:04:11 -0700226static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700228 mss->tsk = current;
229 current->state = TASK_INTERRUPTIBLE;
230 list_add_tail(&mss->list, &msq->q_senders);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231}
232
Ingo Molnar5a06a362006-07-30 03:04:11 -0700233static inline void ss_del(struct msg_sender *mss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700235 if (mss->list.next != NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 list_del(&mss->list);
237}
238
Ingo Molnar5a06a362006-07-30 03:04:11 -0700239static void ss_wakeup(struct list_head *h, int kill)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240{
241 struct list_head *tmp;
242
243 tmp = h->next;
244 while (tmp != h) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700245 struct msg_sender *mss;
246
247 mss = list_entry(tmp, struct msg_sender, list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 tmp = tmp->next;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700249 if (kill)
250 mss->list.next = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 wake_up_process(mss->tsk);
252 }
253}
254
Ingo Molnar5a06a362006-07-30 03:04:11 -0700255static void expunge_all(struct msg_queue *msq, int res)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256{
257 struct list_head *tmp;
258
259 tmp = msq->q_receivers.next;
260 while (tmp != &msq->q_receivers) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700261 struct msg_receiver *msr;
262
263 msr = list_entry(tmp, struct msg_receiver, r_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 tmp = tmp->next;
265 msr->r_msg = NULL;
266 wake_up_process(msr->r_tsk);
267 smp_mb();
268 msr->r_msg = ERR_PTR(res);
269 }
270}
Ingo Molnar5a06a362006-07-30 03:04:11 -0700271
272/*
273 * freeque() wakes up waiters on the sender and receiver waiting queue,
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700274 * removes the message queue from message queue ID IDR, and cleans up all the
275 * messages associated with this queue.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 *
Nadia Derbey3e148c72007-10-18 23:40:54 -0700277 * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held
278 * before freeque() is called. msg_ids.rw_mutex remains locked on exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 */
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800280static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281{
282 struct list_head *tmp;
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800283 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284
Ingo Molnar5a06a362006-07-30 03:04:11 -0700285 expunge_all(msq, -EIDRM);
286 ss_wakeup(&msq->q_senders, 1);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700287 msg_rmid(ns, msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 msg_unlock(msq);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 tmp = msq->q_messages.next;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700291 while (tmp != &msq->q_messages) {
292 struct msg_msg *msg = list_entry(tmp, struct msg_msg, m_list);
293
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 tmp = tmp->next;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700295 atomic_dec(&ns->msg_hdrs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 free_msg(msg);
297 }
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700298 atomic_sub(msq->q_cbytes, &ns->msg_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 security_msg_queue_free(msq);
300 ipc_rcu_putref(msq);
301}
302
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700303/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700304 * Called with msg_ids.rw_mutex and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700305 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700306static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700307{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700308 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
309
310 return security_msg_queue_associate(msq, msgflg);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700311}
312
Heiko Carstense48fbb62009-01-14 14:14:26 +0100313SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314{
Kirill Korotaev1e786932006-10-02 02:18:21 -0700315 struct ipc_namespace *ns;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700316 struct ipc_ops msg_ops;
317 struct ipc_params msg_params;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700318
319 ns = current->nsproxy->ipc_ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700320
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700321 msg_ops.getnew = newque;
322 msg_ops.associate = msg_security;
323 msg_ops.more_checks = NULL;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700324
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700325 msg_params.key = key;
326 msg_params.flg = msgflg;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700327
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700328 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329}
330
Ingo Molnar5a06a362006-07-30 03:04:11 -0700331static inline unsigned long
332copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333{
334 switch(version) {
335 case IPC_64:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700336 return copy_to_user(buf, in, sizeof(*in));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 case IPC_OLD:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700338 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 struct msqid_ds out;
340
Ingo Molnar5a06a362006-07-30 03:04:11 -0700341 memset(&out, 0, sizeof(out));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342
343 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
344
345 out.msg_stime = in->msg_stime;
346 out.msg_rtime = in->msg_rtime;
347 out.msg_ctime = in->msg_ctime;
348
Alexey Dobriyan4be929b2010-05-24 14:33:03 -0700349 if (in->msg_cbytes > USHRT_MAX)
350 out.msg_cbytes = USHRT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 else
352 out.msg_cbytes = in->msg_cbytes;
353 out.msg_lcbytes = in->msg_cbytes;
354
Alexey Dobriyan4be929b2010-05-24 14:33:03 -0700355 if (in->msg_qnum > USHRT_MAX)
356 out.msg_qnum = USHRT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 else
358 out.msg_qnum = in->msg_qnum;
359
Alexey Dobriyan4be929b2010-05-24 14:33:03 -0700360 if (in->msg_qbytes > USHRT_MAX)
361 out.msg_qbytes = USHRT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 else
363 out.msg_qbytes = in->msg_qbytes;
364 out.msg_lqbytes = in->msg_qbytes;
365
366 out.msg_lspid = in->msg_lspid;
367 out.msg_lrpid = in->msg_lrpid;
368
Ingo Molnar5a06a362006-07-30 03:04:11 -0700369 return copy_to_user(buf, &out, sizeof(out));
370 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 default:
372 return -EINVAL;
373 }
374}
375
Ingo Molnar5a06a362006-07-30 03:04:11 -0700376static inline unsigned long
Pierre Peiffer016d7132008-04-29 01:00:50 -0700377copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378{
379 switch(version) {
380 case IPC_64:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700381 if (copy_from_user(out, buf, sizeof(*out)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 case IPC_OLD:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700385 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 struct msqid_ds tbuf_old;
387
Ingo Molnar5a06a362006-07-30 03:04:11 -0700388 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 return -EFAULT;
390
Pierre Peiffer016d7132008-04-29 01:00:50 -0700391 out->msg_perm.uid = tbuf_old.msg_perm.uid;
392 out->msg_perm.gid = tbuf_old.msg_perm.gid;
393 out->msg_perm.mode = tbuf_old.msg_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394
Ingo Molnar5a06a362006-07-30 03:04:11 -0700395 if (tbuf_old.msg_qbytes == 0)
Pierre Peiffer016d7132008-04-29 01:00:50 -0700396 out->msg_qbytes = tbuf_old.msg_lqbytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 else
Pierre Peiffer016d7132008-04-29 01:00:50 -0700398 out->msg_qbytes = tbuf_old.msg_qbytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399
400 return 0;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700401 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 default:
403 return -EINVAL;
404 }
405}
406
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700407/*
408 * This function handles some msgctl commands which require the rw_mutex
409 * to be held in write mode.
410 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
411 */
412static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
413 struct msqid_ds __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 struct kern_ipc_perm *ipcp;
Felipe Contrerasf1970c42009-10-19 01:54:29 +0300416 struct msqid64_ds uninitialized_var(msqid64);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700417 struct msg_queue *msq;
418 int err;
419
420 if (cmd == IPC_SET) {
Pierre Peiffer016d7132008-04-29 01:00:50 -0700421 if (copy_msqid_from_user(&msqid64, buf, version))
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700422 return -EFAULT;
423 }
424
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700425 ipcp = ipcctl_pre_down(ns, &msg_ids(ns), msqid, cmd,
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700426 &msqid64.msg_perm, msqid64.msg_qbytes);
427 if (IS_ERR(ipcp))
428 return PTR_ERR(ipcp);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700429
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700430 msq = container_of(ipcp, struct msg_queue, q_perm);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700431
432 err = security_msg_queue_msgctl(msq, cmd);
433 if (err)
434 goto out_unlock;
435
436 switch (cmd) {
437 case IPC_RMID:
438 freeque(ns, ipcp);
439 goto out_up;
440 case IPC_SET:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700441 if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700442 !capable(CAP_SYS_RESOURCE)) {
443 err = -EPERM;
444 goto out_unlock;
445 }
446
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800447 err = ipc_update_perm(&msqid64.msg_perm, ipcp);
448 if (err)
449 goto out_unlock;
450
Pierre Peiffer016d7132008-04-29 01:00:50 -0700451 msq->q_qbytes = msqid64.msg_qbytes;
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700452
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700453 msq->q_ctime = get_seconds();
454 /* sleeping receivers might be excluded by
455 * stricter permissions.
456 */
457 expunge_all(msq, -EAGAIN);
458 /* sleeping senders might be able to send
459 * due to a larger queue size.
460 */
461 ss_wakeup(&msq->q_senders, 0);
462 break;
463 default:
464 err = -EINVAL;
465 }
466out_unlock:
467 msg_unlock(msq);
468out_up:
469 up_write(&msg_ids(ns).rw_mutex);
470 return err;
471}
472
Heiko Carstense48fbb62009-01-14 14:14:26 +0100473SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700474{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700475 struct msg_queue *msq;
476 int err, version;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700477 struct ipc_namespace *ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700478
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 if (msqid < 0 || cmd < 0)
480 return -EINVAL;
481
482 version = ipc_parse_version(&cmd);
Kirill Korotaev1e786932006-10-02 02:18:21 -0700483 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484
485 switch (cmd) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700486 case IPC_INFO:
487 case MSG_INFO:
488 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 struct msginfo msginfo;
490 int max_id;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700491
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 if (!buf)
493 return -EFAULT;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700494 /*
495 * We must not return kernel stack data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 * due to padding, it's not enough
497 * to set all member fields.
498 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 err = security_msg_queue_msgctl(NULL, cmd);
500 if (err)
501 return err;
502
Ingo Molnar5a06a362006-07-30 03:04:11 -0700503 memset(&msginfo, 0, sizeof(msginfo));
Kirill Korotaev1e786932006-10-02 02:18:21 -0700504 msginfo.msgmni = ns->msg_ctlmni;
505 msginfo.msgmax = ns->msg_ctlmax;
506 msginfo.msgmnb = ns->msg_ctlmnb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 msginfo.msgssz = MSGSSZ;
508 msginfo.msgseg = MSGSEG;
Nadia Derbey3e148c72007-10-18 23:40:54 -0700509 down_read(&msg_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 if (cmd == MSG_INFO) {
Kirill Korotaev1e786932006-10-02 02:18:21 -0700511 msginfo.msgpool = msg_ids(ns).in_use;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700512 msginfo.msgmap = atomic_read(&ns->msg_hdrs);
513 msginfo.msgtql = atomic_read(&ns->msg_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 } else {
515 msginfo.msgmap = MSGMAP;
516 msginfo.msgpool = MSGPOOL;
517 msginfo.msgtql = MSGTQL;
518 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700519 max_id = ipc_get_maxid(&msg_ids(ns));
Nadia Derbey3e148c72007-10-18 23:40:54 -0700520 up_read(&msg_ids(ns).rw_mutex);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700521 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 return -EFAULT;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700523 return (max_id < 0) ? 0 : max_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700525 case MSG_STAT: /* msqid is an index rather than a msg queue id */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 case IPC_STAT:
527 {
528 struct msqid64_ds tbuf;
529 int success_return;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700530
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 if (!buf)
532 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533
Ingo Molnar5a06a362006-07-30 03:04:11 -0700534 if (cmd == MSG_STAT) {
Nadia Derbey023a5352007-10-18 23:40:51 -0700535 msq = msg_lock(ns, msqid);
536 if (IS_ERR(msq))
537 return PTR_ERR(msq);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700538 success_return = msq->q_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 } else {
Nadia Derbey023a5352007-10-18 23:40:51 -0700540 msq = msg_lock_check(ns, msqid);
541 if (IS_ERR(msq))
542 return PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 success_return = 0;
544 }
545 err = -EACCES;
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700546 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 goto out_unlock;
548
549 err = security_msg_queue_msgctl(msq, cmd);
550 if (err)
551 goto out_unlock;
552
Nadia Derbey023a5352007-10-18 23:40:51 -0700553 memset(&tbuf, 0, sizeof(tbuf));
554
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
556 tbuf.msg_stime = msq->q_stime;
557 tbuf.msg_rtime = msq->q_rtime;
558 tbuf.msg_ctime = msq->q_ctime;
559 tbuf.msg_cbytes = msq->q_cbytes;
560 tbuf.msg_qnum = msq->q_qnum;
561 tbuf.msg_qbytes = msq->q_qbytes;
562 tbuf.msg_lspid = msq->q_lspid;
563 tbuf.msg_lrpid = msq->q_lrpid;
564 msg_unlock(msq);
565 if (copy_msqid_to_user(buf, &tbuf, version))
566 return -EFAULT;
567 return success_return;
568 }
569 case IPC_SET:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 case IPC_RMID:
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700571 err = msgctl_down(ns, msqid, cmd, buf, version);
572 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 default:
574 return -EINVAL;
575 }
576
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577out_unlock:
578 msg_unlock(msq);
579 return err;
580}
581
Ingo Molnar5a06a362006-07-30 03:04:11 -0700582static int testmsg(struct msg_msg *msg, long type, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583{
584 switch(mode)
585 {
586 case SEARCH_ANY:
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700587 case SEARCH_NUMBER:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 return 1;
589 case SEARCH_LESSEQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700590 if (msg->m_type <=type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 return 1;
592 break;
593 case SEARCH_EQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700594 if (msg->m_type == type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 return 1;
596 break;
597 case SEARCH_NOTEQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700598 if (msg->m_type != type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 return 1;
600 break;
601 }
602 return 0;
603}
604
Ingo Molnar5a06a362006-07-30 03:04:11 -0700605static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700607 struct list_head *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608
609 tmp = msq->q_receivers.next;
610 while (tmp != &msq->q_receivers) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700611 struct msg_receiver *msr;
612
613 msr = list_entry(tmp, struct msg_receiver, r_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 tmp = tmp->next;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700615 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
616 !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
617 msr->r_msgtype, msr->r_mode)) {
618
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 list_del(&msr->r_list);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700620 if (msr->r_maxsize < msg->m_ts) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 msr->r_msg = NULL;
622 wake_up_process(msr->r_tsk);
623 smp_mb();
624 msr->r_msg = ERR_PTR(-E2BIG);
625 } else {
626 msr->r_msg = NULL;
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700627 msq->q_lrpid = task_pid_vnr(msr->r_tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628 msq->q_rtime = get_seconds();
629 wake_up_process(msr->r_tsk);
630 smp_mb();
631 msr->r_msg = msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700632
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 return 1;
634 }
635 }
636 }
637 return 0;
638}
639
suzuki651971c2006-12-06 20:37:48 -0800640long do_msgsnd(int msqid, long mtype, void __user *mtext,
641 size_t msgsz, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642{
643 struct msg_queue *msq;
644 struct msg_msg *msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 int err;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700646 struct ipc_namespace *ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700647
Kirill Korotaev1e786932006-10-02 02:18:21 -0700648 ns = current->nsproxy->ipc_ns;
649
650 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 if (mtype < 1)
653 return -EINVAL;
654
suzuki651971c2006-12-06 20:37:48 -0800655 msg = load_msg(mtext, msgsz);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700656 if (IS_ERR(msg))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 return PTR_ERR(msg);
658
659 msg->m_type = mtype;
660 msg->m_ts = msgsz;
661
Nadia Derbey023a5352007-10-18 23:40:51 -0700662 msq = msg_lock_check(ns, msqid);
663 if (IS_ERR(msq)) {
664 err = PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 goto out_free;
Nadia Derbey023a5352007-10-18 23:40:51 -0700666 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667
668 for (;;) {
669 struct msg_sender s;
670
Ingo Molnar5a06a362006-07-30 03:04:11 -0700671 err = -EACCES;
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700672 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 goto out_unlock_free;
674
675 err = security_msg_queue_msgsnd(msq, msg, msgflg);
676 if (err)
677 goto out_unlock_free;
678
Ingo Molnar5a06a362006-07-30 03:04:11 -0700679 if (msgsz + msq->q_cbytes <= msq->q_qbytes &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 1 + msq->q_qnum <= msq->q_qbytes) {
681 break;
682 }
683
684 /* queue full, wait: */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700685 if (msgflg & IPC_NOWAIT) {
686 err = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 goto out_unlock_free;
688 }
689 ss_add(msq, &s);
Rik van Riel6062a8d2013-04-30 19:15:44 -0700690
691 if (!ipc_rcu_getref(msq)) {
692 err = -EIDRM;
693 goto out_unlock_free;
694 }
695
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 msg_unlock(msq);
697 schedule();
698
699 ipc_lock_by_ptr(&msq->q_perm);
700 ipc_rcu_putref(msq);
701 if (msq->q_perm.deleted) {
702 err = -EIDRM;
703 goto out_unlock_free;
704 }
705 ss_del(&s);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700706
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 if (signal_pending(current)) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700708 err = -ERESTARTNOHAND;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 goto out_unlock_free;
710 }
711 }
712
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700713 msq->q_lspid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 msq->q_stime = get_seconds();
715
Ingo Molnar5a06a362006-07-30 03:04:11 -0700716 if (!pipelined_send(msq, msg)) {
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300717 /* no one is waiting for this message, enqueue it */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700718 list_add_tail(&msg->m_list, &msq->q_messages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 msq->q_cbytes += msgsz;
720 msq->q_qnum++;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700721 atomic_add(msgsz, &ns->msg_bytes);
722 atomic_inc(&ns->msg_hdrs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700724
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 err = 0;
726 msg = NULL;
727
728out_unlock_free:
729 msg_unlock(msq);
730out_free:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700731 if (msg != NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 free_msg(msg);
733 return err;
734}
735
Heiko Carstense48fbb62009-01-14 14:14:26 +0100736SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
737 int, msgflg)
suzuki651971c2006-12-06 20:37:48 -0800738{
739 long mtype;
740
741 if (get_user(mtype, &msgp->mtype))
742 return -EFAULT;
743 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
744}
745
Ingo Molnar5a06a362006-07-30 03:04:11 -0700746static inline int convert_mode(long *msgtyp, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747{
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700748 if (msgflg & MSG_COPY)
749 return SEARCH_NUMBER;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700750 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 * find message of correct type.
752 * msgtyp = 0 => get first.
753 * msgtyp > 0 => get first message of matching type.
Ingo Molnar5a06a362006-07-30 03:04:11 -0700754 * msgtyp < 0 => get message with least type must be < abs(msgtype).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700756 if (*msgtyp == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 return SEARCH_ANY;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700758 if (*msgtyp < 0) {
759 *msgtyp = -*msgtyp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 return SEARCH_LESSEQUAL;
761 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700762 if (msgflg & MSG_EXCEPT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 return SEARCH_NOTEQUAL;
764 return SEARCH_EQUAL;
765}
766
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800767static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
768{
769 struct msgbuf __user *msgp = dest;
770 size_t msgsz;
771
772 if (put_user(msg->m_type, &msgp->mtype))
773 return -EFAULT;
774
775 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
776 if (store_msg(msgp->mtext, msg, msgsz))
777 return -EFAULT;
778 return msgsz;
779}
780
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800781#ifdef CONFIG_CHECKPOINT_RESTORE
Stanislav Kinsbursky3fcfe782013-01-04 15:35:03 -0800782/*
783 * This function creates new kernel message structure, large enough to store
784 * bufsz message bytes.
785 */
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700786static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800787{
788 struct msg_msg *copy;
789
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800790 /*
791 * Create dummy message to copy real message to.
792 */
793 copy = load_msg(buf, bufsz);
794 if (!IS_ERR(copy))
795 copy->m_ts = bufsz;
796 return copy;
797}
798
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800799static inline void free_copy(struct msg_msg *copy)
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800800{
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800801 if (copy)
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800802 free_msg(copy);
803}
804#else
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700805static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
Stanislav Kinsburskyb30efe22013-01-04 15:35:00 -0800806{
807 return ERR_PTR(-ENOSYS);
808}
809
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800810static inline void free_copy(struct msg_msg *copy)
811{
812}
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800813#endif
814
Peter Hurleydaaf74c2013-04-30 19:15:04 -0700815static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
816{
817 struct msg_msg *msg;
818 long count = 0;
819
820 list_for_each_entry(msg, &msq->q_messages, m_list) {
821 if (testmsg(msg, *msgtyp, mode) &&
822 !security_msg_queue_msgrcv(msq, msg, current,
823 *msgtyp, mode)) {
824 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
825 *msgtyp = msg->m_type - 1;
826 } else if (mode == SEARCH_NUMBER) {
827 if (*msgtyp == count)
828 return msg;
829 } else
830 return msg;
831 count++;
832 }
833 }
834
835 return ERR_PTR(-EAGAIN);
836}
837
838
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800839long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
840 int msgflg,
841 long (*msg_handler)(void __user *, struct msg_msg *, size_t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842{
843 struct msg_queue *msq;
844 struct msg_msg *msg;
845 int mode;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700846 struct ipc_namespace *ns;
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800847 struct msg_msg *copy = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848
Peter Hurley88b9e452013-03-08 12:43:27 -0800849 ns = current->nsproxy->ipc_ns;
850
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800851 if (msqid < 0 || (long) bufsz < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 return -EINVAL;
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800853 if (msgflg & MSG_COPY) {
Peter Hurley8ac6ed52013-04-30 19:14:54 -0700854 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800855 if (IS_ERR(copy))
856 return PTR_ERR(copy);
857 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700858 mode = convert_mode(&msgtyp, msgflg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859
Nadia Derbey023a5352007-10-18 23:40:51 -0700860 msq = msg_lock_check(ns, msqid);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800861 if (IS_ERR(msq)) {
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800862 free_copy(copy);
Nadia Derbey023a5352007-10-18 23:40:51 -0700863 return PTR_ERR(msq);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800864 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865
866 for (;;) {
867 struct msg_receiver msr_d;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868
869 msg = ERR_PTR(-EACCES);
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700870 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 goto out_unlock;
872
Peter Hurleydaaf74c2013-04-30 19:15:04 -0700873 msg = find_msg(msq, &msgtyp, mode);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700874
Ingo Molnar5a06a362006-07-30 03:04:11 -0700875 if (!IS_ERR(msg)) {
876 /*
877 * Found a suitable message.
878 * Unlink it from the queue.
879 */
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800880 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 msg = ERR_PTR(-E2BIG);
882 goto out_unlock;
883 }
Stanislav Kinsbursky3fcfe782013-01-04 15:35:03 -0800884 /*
885 * If we are copying, then do not unlink message and do
886 * not update queue parameters.
887 */
Peter Hurley852028a2013-04-30 19:14:48 -0700888 if (msgflg & MSG_COPY) {
889 msg = copy_msg(msg, copy);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800890 goto out_unlock;
Peter Hurley852028a2013-04-30 19:14:48 -0700891 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 list_del(&msg->m_list);
893 msq->q_qnum--;
894 msq->q_rtime = get_seconds();
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700895 msq->q_lrpid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 msq->q_cbytes -= msg->m_ts;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700897 atomic_sub(msg->m_ts, &ns->msg_bytes);
898 atomic_dec(&ns->msg_hdrs);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700899 ss_wakeup(&msq->q_senders, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 msg_unlock(msq);
901 break;
902 }
903 /* No message waiting. Wait for a message */
904 if (msgflg & IPC_NOWAIT) {
905 msg = ERR_PTR(-ENOMSG);
906 goto out_unlock;
907 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700908 list_add_tail(&msr_d.r_list, &msq->q_receivers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909 msr_d.r_tsk = current;
910 msr_d.r_msgtype = msgtyp;
911 msr_d.r_mode = mode;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700912 if (msgflg & MSG_NOERROR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 msr_d.r_maxsize = INT_MAX;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700914 else
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800915 msr_d.r_maxsize = bufsz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 msr_d.r_msg = ERR_PTR(-EAGAIN);
917 current->state = TASK_INTERRUPTIBLE;
918 msg_unlock(msq);
919
920 schedule();
921
922 /* Lockless receive, part 1:
923 * Disable preemption. We don't hold a reference to the queue
924 * and getting a reference would defeat the idea of a lockless
925 * operation, thus the code relies on rcu to guarantee the
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300926 * existence of msq:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
928 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
929 * rcu_read_lock() prevents preemption between reading r_msg
930 * and the spin_lock() inside ipc_lock_by_ptr().
931 */
932 rcu_read_lock();
933
934 /* Lockless receive, part 2:
935 * Wait until pipelined_send or expunge_all are outside of
936 * wake_up_process(). There is a race with exit(), see
937 * ipc/mqueue.c for the details.
938 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700939 msg = (struct msg_msg*)msr_d.r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700940 while (msg == NULL) {
941 cpu_relax();
Ingo Molnar5a06a362006-07-30 03:04:11 -0700942 msg = (struct msg_msg *)msr_d.r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943 }
944
945 /* Lockless receive, part 3:
946 * If there is a message or an error then accept it without
947 * locking.
948 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700949 if (msg != ERR_PTR(-EAGAIN)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950 rcu_read_unlock();
951 break;
952 }
953
954 /* Lockless receive, part 3:
955 * Acquire the queue spinlock.
956 */
957 ipc_lock_by_ptr(&msq->q_perm);
958 rcu_read_unlock();
959
960 /* Lockless receive, part 4:
961 * Repeat test after acquiring the spinlock.
962 */
963 msg = (struct msg_msg*)msr_d.r_msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700964 if (msg != ERR_PTR(-EAGAIN))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 goto out_unlock;
966
967 list_del(&msr_d.r_list);
968 if (signal_pending(current)) {
969 msg = ERR_PTR(-ERESTARTNOHAND);
970out_unlock:
971 msg_unlock(msq);
972 break;
973 }
974 }
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800975 if (IS_ERR(msg)) {
Stanislav Kinsbursky85398aa2013-01-04 15:34:58 -0800976 free_copy(copy);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700977 return PTR_ERR(msg);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800978 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800980 bufsz = msg_handler(buf, msg, bufsz);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 free_msg(msg);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700982
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800983 return bufsz;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984}
985
Heiko Carstense48fbb62009-01-14 14:14:26 +0100986SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
987 long, msgtyp, int, msgflg)
suzuki651971c2006-12-06 20:37:48 -0800988{
Stanislav Kinsburskyf9dd87f2013-01-04 15:34:52 -0800989 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
suzuki651971c2006-12-06 20:37:48 -0800990}
991
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -0700993static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994{
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800995 struct user_namespace *user_ns = seq_user_ns(s);
Mike Waychison19b49462005-09-06 15:17:10 -0700996 struct msg_queue *msq = it;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997
Mike Waychison19b49462005-09-06 15:17:10 -0700998 return seq_printf(s,
Ingo Molnar5a06a362006-07-30 03:04:11 -0700999 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
1000 msq->q_perm.key,
Nadia Derbey7ca7e562007-10-18 23:40:48 -07001001 msq->q_perm.id,
Ingo Molnar5a06a362006-07-30 03:04:11 -07001002 msq->q_perm.mode,
1003 msq->q_cbytes,
1004 msq->q_qnum,
1005 msq->q_lspid,
1006 msq->q_lrpid,
Eric W. Biederman1efdb692012-02-07 16:54:11 -08001007 from_kuid_munged(user_ns, msq->q_perm.uid),
1008 from_kgid_munged(user_ns, msq->q_perm.gid),
1009 from_kuid_munged(user_ns, msq->q_perm.cuid),
1010 from_kgid_munged(user_ns, msq->q_perm.cgid),
Ingo Molnar5a06a362006-07-30 03:04:11 -07001011 msq->q_stime,
1012 msq->q_rtime,
1013 msq->q_ctime);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014}
1015#endif