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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/slab.h>
27#include <linux/msg.h>
28#include <linux/spinlock.h>
29#include <linux/init.h>
Nadia Derbeyf7bf3df2008-04-29 01:00:39 -070030#include <linux/mm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <linux/proc_fs.h>
32#include <linux/list.h>
33#include <linux/security.h>
34#include <linux/sched.h>
35#include <linux/syscalls.h>
36#include <linux/audit.h>
Mike Waychison19b49462005-09-06 15:17:10 -070037#include <linux/seq_file.h>
Nadia Derbey3e148c72007-10-18 23:40:54 -070038#include <linux/rwsem.h>
Kirill Korotaev1e786932006-10-02 02:18:21 -070039#include <linux/nsproxy.h>
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080040#include <linux/ipc_namespace.h>
Ingo Molnar5f921ae2006-03-26 01:37:17 -080041
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <asm/current.h>
43#include <asm/uaccess.h>
44#include "util.h"
45
Ingo Molnar5a06a362006-07-30 03:04:11 -070046/*
47 * one msg_receiver structure for each sleeping receiver:
48 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070049struct msg_receiver {
Ingo Molnar5a06a362006-07-30 03:04:11 -070050 struct list_head r_list;
51 struct task_struct *r_tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
Ingo Molnar5a06a362006-07-30 03:04:11 -070053 int r_mode;
54 long r_msgtype;
55 long r_maxsize;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
Linus Torvalds80491eb2006-11-04 09:55:00 -080057 struct msg_msg *volatile r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -070058};
59
60/* one msg_sender for each sleeping sender */
61struct msg_sender {
Ingo Molnar5a06a362006-07-30 03:04:11 -070062 struct list_head list;
63 struct task_struct *tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -070064};
65
66#define SEARCH_ANY 1
67#define SEARCH_EQUAL 2
68#define SEARCH_NOTEQUAL 3
69#define SEARCH_LESSEQUAL 4
70
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);
Kirill Korotaev1e786932006-10-02 02:18:21 -0700128}
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800129#endif
Kirill Korotaev1e786932006-10-02 02:18:21 -0700130
131void __init msg_init(void)
132{
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800133 msg_init_ns(&init_ipc_ns);
Nadia Derbeydfcceb22008-06-05 22:46:38 -0700134
135 printk(KERN_INFO "msgmni has been set to %d\n",
136 init_ipc_ns.msg_ctlmni);
137
Kirill Korotaev1e786932006-10-02 02:18:21 -0700138 ipc_init_proc_interface("sysvipc/msg",
139 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
140 IPC_MSG_IDS, sysvipc_msg_proc_show);
141}
142
Nadia Derbey3e148c72007-10-18 23:40:54 -0700143/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700144 * msg_lock_(check_) routines are called in the paths where the rw_mutex
145 * is not held.
146 */
Nadia Derbey023a5352007-10-18 23:40:51 -0700147static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id)
148{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700149 struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id);
150
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800151 if (IS_ERR(ipcp))
152 return (struct msg_queue *)ipcp;
153
Nadia Derbey03f02c72007-10-18 23:40:51 -0700154 return container_of(ipcp, struct msg_queue, q_perm);
Nadia Derbey023a5352007-10-18 23:40:51 -0700155}
156
157static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns,
158 int id)
159{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700160 struct kern_ipc_perm *ipcp = ipc_lock_check(&msg_ids(ns), id);
161
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800162 if (IS_ERR(ipcp))
163 return (struct msg_queue *)ipcp;
164
Nadia Derbey03f02c72007-10-18 23:40:51 -0700165 return container_of(ipcp, struct msg_queue, q_perm);
Nadia Derbey023a5352007-10-18 23:40:51 -0700166}
167
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700168static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
169{
170 ipc_rmid(&msg_ids(ns), &s->q_perm);
171}
172
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700173/**
174 * newque - Create a new msg queue
175 * @ns: namespace
176 * @params: ptr to the structure that contains the key and msgflg
177 *
Nadia Derbey3e148c72007-10-18 23:40:54 -0700178 * Called with msg_ids.rw_mutex held (writer)
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700179 */
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700180static int newque(struct ipc_namespace *ns, struct ipc_params *params)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 struct msg_queue *msq;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700183 int id, retval;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700184 key_t key = params->key;
185 int msgflg = params->flg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186
Ingo Molnar5a06a362006-07-30 03:04:11 -0700187 msq = ipc_rcu_alloc(sizeof(*msq));
188 if (!msq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 return -ENOMEM;
190
Ingo Molnar5a06a362006-07-30 03:04:11 -0700191 msq->q_perm.mode = msgflg & S_IRWXUGO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 msq->q_perm.key = key;
193
194 msq->q_perm.security = NULL;
195 retval = security_msg_queue_alloc(msq);
196 if (retval) {
197 ipc_rcu_putref(msq);
198 return retval;
199 }
200
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700201 /*
202 * ipc_addid() locks msq
203 */
Kirill Korotaev1e786932006-10-02 02:18:21 -0700204 id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700205 if (id < 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 security_msg_queue_free(msq);
207 ipc_rcu_putref(msq);
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700208 return id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 }
210
211 msq->q_stime = msq->q_rtime = 0;
212 msq->q_ctime = get_seconds();
213 msq->q_cbytes = msq->q_qnum = 0;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700214 msq->q_qbytes = ns->msg_ctlmnb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 msq->q_lspid = msq->q_lrpid = 0;
216 INIT_LIST_HEAD(&msq->q_messages);
217 INIT_LIST_HEAD(&msq->q_receivers);
218 INIT_LIST_HEAD(&msq->q_senders);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700219
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 msg_unlock(msq);
221
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{
240 struct list_head *tmp;
241
242 tmp = h->next;
243 while (tmp != h) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700244 struct msg_sender *mss;
245
246 mss = list_entry(tmp, struct msg_sender, list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 tmp = tmp->next;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700248 if (kill)
249 mss->list.next = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 wake_up_process(mss->tsk);
251 }
252}
253
Ingo Molnar5a06a362006-07-30 03:04:11 -0700254static void expunge_all(struct msg_queue *msq, int res)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255{
256 struct list_head *tmp;
257
258 tmp = msq->q_receivers.next;
259 while (tmp != &msq->q_receivers) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700260 struct msg_receiver *msr;
261
262 msr = list_entry(tmp, struct msg_receiver, r_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 tmp = tmp->next;
264 msr->r_msg = NULL;
265 wake_up_process(msr->r_tsk);
266 smp_mb();
267 msr->r_msg = ERR_PTR(res);
268 }
269}
Ingo Molnar5a06a362006-07-30 03:04:11 -0700270
271/*
272 * freeque() wakes up waiters on the sender and receiver waiting queue,
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700273 * removes the message queue from message queue ID IDR, and cleans up all the
274 * messages associated with this queue.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 *
Nadia Derbey3e148c72007-10-18 23:40:54 -0700276 * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held
277 * before freeque() is called. msg_ids.rw_mutex remains locked on exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 */
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800279static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280{
281 struct list_head *tmp;
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800282 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
Ingo Molnar5a06a362006-07-30 03:04:11 -0700284 expunge_all(msq, -EIDRM);
285 ss_wakeup(&msq->q_senders, 1);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700286 msg_rmid(ns, msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 msg_unlock(msq);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700288
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 tmp = msq->q_messages.next;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700290 while (tmp != &msq->q_messages) {
291 struct msg_msg *msg = list_entry(tmp, struct msg_msg, m_list);
292
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 tmp = tmp->next;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700294 atomic_dec(&ns->msg_hdrs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 free_msg(msg);
296 }
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700297 atomic_sub(msq->q_cbytes, &ns->msg_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 security_msg_queue_free(msq);
299 ipc_rcu_putref(msq);
300}
301
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700302/*
Nadia Derbey3e148c72007-10-18 23:40:54 -0700303 * Called with msg_ids.rw_mutex and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700304 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700305static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700306{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700307 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
308
309 return security_msg_queue_associate(msq, msgflg);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700310}
311
Ingo Molnar5a06a362006-07-30 03:04:11 -0700312asmlinkage long sys_msgget(key_t key, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313{
Kirill Korotaev1e786932006-10-02 02:18:21 -0700314 struct ipc_namespace *ns;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700315 struct ipc_ops msg_ops;
316 struct ipc_params msg_params;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700317
318 ns = current->nsproxy->ipc_ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700319
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700320 msg_ops.getnew = newque;
321 msg_ops.associate = msg_security;
322 msg_ops.more_checks = NULL;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700323
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700324 msg_params.key = key;
325 msg_params.flg = msgflg;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700326
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700327 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328}
329
Ingo Molnar5a06a362006-07-30 03:04:11 -0700330static inline unsigned long
331copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332{
333 switch(version) {
334 case IPC_64:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700335 return copy_to_user(buf, in, sizeof(*in));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 case IPC_OLD:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700337 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 struct msqid_ds out;
339
Ingo Molnar5a06a362006-07-30 03:04:11 -0700340 memset(&out, 0, sizeof(out));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341
342 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
343
344 out.msg_stime = in->msg_stime;
345 out.msg_rtime = in->msg_rtime;
346 out.msg_ctime = in->msg_ctime;
347
Zhang, Yanmin44f564a2008-04-29 01:00:55 -0700348 if (in->msg_cbytes > USHORT_MAX)
349 out.msg_cbytes = USHORT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 else
351 out.msg_cbytes = in->msg_cbytes;
352 out.msg_lcbytes = in->msg_cbytes;
353
Zhang, Yanmin44f564a2008-04-29 01:00:55 -0700354 if (in->msg_qnum > USHORT_MAX)
355 out.msg_qnum = USHORT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 else
357 out.msg_qnum = in->msg_qnum;
358
Zhang, Yanmin44f564a2008-04-29 01:00:55 -0700359 if (in->msg_qbytes > USHORT_MAX)
360 out.msg_qbytes = USHORT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 else
362 out.msg_qbytes = in->msg_qbytes;
363 out.msg_lqbytes = in->msg_qbytes;
364
365 out.msg_lspid = in->msg_lspid;
366 out.msg_lrpid = in->msg_lrpid;
367
Ingo Molnar5a06a362006-07-30 03:04:11 -0700368 return copy_to_user(buf, &out, sizeof(out));
369 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 default:
371 return -EINVAL;
372 }
373}
374
Ingo Molnar5a06a362006-07-30 03:04:11 -0700375static inline unsigned long
Pierre Peiffer016d7132008-04-29 01:00:50 -0700376copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377{
378 switch(version) {
379 case IPC_64:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700380 if (copy_from_user(out, buf, sizeof(*out)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 case IPC_OLD:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700384 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 struct msqid_ds tbuf_old;
386
Ingo Molnar5a06a362006-07-30 03:04:11 -0700387 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 return -EFAULT;
389
Pierre Peiffer016d7132008-04-29 01:00:50 -0700390 out->msg_perm.uid = tbuf_old.msg_perm.uid;
391 out->msg_perm.gid = tbuf_old.msg_perm.gid;
392 out->msg_perm.mode = tbuf_old.msg_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393
Ingo Molnar5a06a362006-07-30 03:04:11 -0700394 if (tbuf_old.msg_qbytes == 0)
Pierre Peiffer016d7132008-04-29 01:00:50 -0700395 out->msg_qbytes = tbuf_old.msg_lqbytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 else
Pierre Peiffer016d7132008-04-29 01:00:50 -0700397 out->msg_qbytes = tbuf_old.msg_qbytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398
399 return 0;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700400 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 default:
402 return -EINVAL;
403 }
404}
405
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700406/*
407 * This function handles some msgctl commands which require the rw_mutex
408 * to be held in write mode.
409 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
410 */
411static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
412 struct msqid_ds __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 struct kern_ipc_perm *ipcp;
Pierre Peiffer016d7132008-04-29 01:00:50 -0700415 struct msqid64_ds msqid64;
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700416 struct msg_queue *msq;
417 int err;
418
419 if (cmd == IPC_SET) {
Pierre Peiffer016d7132008-04-29 01:00:50 -0700420 if (copy_msqid_from_user(&msqid64, buf, version))
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700421 return -EFAULT;
422 }
423
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700424 ipcp = ipcctl_pre_down(&msg_ids(ns), msqid, cmd,
425 &msqid64.msg_perm, msqid64.msg_qbytes);
426 if (IS_ERR(ipcp))
427 return PTR_ERR(ipcp);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700428
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700429 msq = container_of(ipcp, struct msg_queue, q_perm);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700430
431 err = security_msg_queue_msgctl(msq, cmd);
432 if (err)
433 goto out_unlock;
434
435 switch (cmd) {
436 case IPC_RMID:
437 freeque(ns, ipcp);
438 goto out_up;
439 case IPC_SET:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700440 if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700441 !capable(CAP_SYS_RESOURCE)) {
442 err = -EPERM;
443 goto out_unlock;
444 }
445
Pierre Peiffer016d7132008-04-29 01:00:50 -0700446 msq->q_qbytes = msqid64.msg_qbytes;
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700447
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700448 ipc_update_perm(&msqid64.msg_perm, ipcp);
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700449 msq->q_ctime = get_seconds();
450 /* sleeping receivers might be excluded by
451 * stricter permissions.
452 */
453 expunge_all(msq, -EAGAIN);
454 /* sleeping senders might be able to send
455 * due to a larger queue size.
456 */
457 ss_wakeup(&msq->q_senders, 0);
458 break;
459 default:
460 err = -EINVAL;
461 }
462out_unlock:
463 msg_unlock(msq);
464out_up:
465 up_write(&msg_ids(ns).rw_mutex);
466 return err;
467}
468
469asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
470{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700471 struct msg_queue *msq;
472 int err, version;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700473 struct ipc_namespace *ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700474
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 if (msqid < 0 || cmd < 0)
476 return -EINVAL;
477
478 version = ipc_parse_version(&cmd);
Kirill Korotaev1e786932006-10-02 02:18:21 -0700479 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480
481 switch (cmd) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700482 case IPC_INFO:
483 case MSG_INFO:
484 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 struct msginfo msginfo;
486 int max_id;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700487
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 if (!buf)
489 return -EFAULT;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700490 /*
491 * We must not return kernel stack data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 * due to padding, it's not enough
493 * to set all member fields.
494 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 err = security_msg_queue_msgctl(NULL, cmd);
496 if (err)
497 return err;
498
Ingo Molnar5a06a362006-07-30 03:04:11 -0700499 memset(&msginfo, 0, sizeof(msginfo));
Kirill Korotaev1e786932006-10-02 02:18:21 -0700500 msginfo.msgmni = ns->msg_ctlmni;
501 msginfo.msgmax = ns->msg_ctlmax;
502 msginfo.msgmnb = ns->msg_ctlmnb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 msginfo.msgssz = MSGSSZ;
504 msginfo.msgseg = MSGSEG;
Nadia Derbey3e148c72007-10-18 23:40:54 -0700505 down_read(&msg_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 if (cmd == MSG_INFO) {
Kirill Korotaev1e786932006-10-02 02:18:21 -0700507 msginfo.msgpool = msg_ids(ns).in_use;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700508 msginfo.msgmap = atomic_read(&ns->msg_hdrs);
509 msginfo.msgtql = atomic_read(&ns->msg_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 } else {
511 msginfo.msgmap = MSGMAP;
512 msginfo.msgpool = MSGPOOL;
513 msginfo.msgtql = MSGTQL;
514 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700515 max_id = ipc_get_maxid(&msg_ids(ns));
Nadia Derbey3e148c72007-10-18 23:40:54 -0700516 up_read(&msg_ids(ns).rw_mutex);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700517 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 return -EFAULT;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700519 return (max_id < 0) ? 0 : max_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700521 case MSG_STAT: /* msqid is an index rather than a msg queue id */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 case IPC_STAT:
523 {
524 struct msqid64_ds tbuf;
525 int success_return;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700526
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 if (!buf)
528 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529
Ingo Molnar5a06a362006-07-30 03:04:11 -0700530 if (cmd == MSG_STAT) {
Nadia Derbey023a5352007-10-18 23:40:51 -0700531 msq = msg_lock(ns, msqid);
532 if (IS_ERR(msq))
533 return PTR_ERR(msq);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700534 success_return = msq->q_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 } else {
Nadia Derbey023a5352007-10-18 23:40:51 -0700536 msq = msg_lock_check(ns, msqid);
537 if (IS_ERR(msq))
538 return PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 success_return = 0;
540 }
541 err = -EACCES;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700542 if (ipcperms(&msq->q_perm, S_IRUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 goto out_unlock;
544
545 err = security_msg_queue_msgctl(msq, cmd);
546 if (err)
547 goto out_unlock;
548
Nadia Derbey023a5352007-10-18 23:40:51 -0700549 memset(&tbuf, 0, sizeof(tbuf));
550
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
552 tbuf.msg_stime = msq->q_stime;
553 tbuf.msg_rtime = msq->q_rtime;
554 tbuf.msg_ctime = msq->q_ctime;
555 tbuf.msg_cbytes = msq->q_cbytes;
556 tbuf.msg_qnum = msq->q_qnum;
557 tbuf.msg_qbytes = msq->q_qbytes;
558 tbuf.msg_lspid = msq->q_lspid;
559 tbuf.msg_lrpid = msq->q_lrpid;
560 msg_unlock(msq);
561 if (copy_msqid_to_user(buf, &tbuf, version))
562 return -EFAULT;
563 return success_return;
564 }
565 case IPC_SET:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 case IPC_RMID:
Pierre Peiffera0d092f2008-04-29 01:00:48 -0700567 err = msgctl_down(ns, msqid, cmd, buf, version);
568 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 default:
570 return -EINVAL;
571 }
572
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573out_unlock:
574 msg_unlock(msq);
575 return err;
576}
577
Ingo Molnar5a06a362006-07-30 03:04:11 -0700578static int testmsg(struct msg_msg *msg, long type, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579{
580 switch(mode)
581 {
582 case SEARCH_ANY:
583 return 1;
584 case SEARCH_LESSEQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700585 if (msg->m_type <=type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 return 1;
587 break;
588 case SEARCH_EQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700589 if (msg->m_type == type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 return 1;
591 break;
592 case SEARCH_NOTEQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700593 if (msg->m_type != type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 return 1;
595 break;
596 }
597 return 0;
598}
599
Ingo Molnar5a06a362006-07-30 03:04:11 -0700600static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700602 struct list_head *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603
604 tmp = msq->q_receivers.next;
605 while (tmp != &msq->q_receivers) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700606 struct msg_receiver *msr;
607
608 msr = list_entry(tmp, struct msg_receiver, r_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 tmp = tmp->next;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700610 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
611 !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
612 msr->r_msgtype, msr->r_mode)) {
613
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 list_del(&msr->r_list);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700615 if (msr->r_maxsize < msg->m_ts) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 msr->r_msg = NULL;
617 wake_up_process(msr->r_tsk);
618 smp_mb();
619 msr->r_msg = ERR_PTR(-E2BIG);
620 } else {
621 msr->r_msg = NULL;
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700622 msq->q_lrpid = task_pid_vnr(msr->r_tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 msq->q_rtime = get_seconds();
624 wake_up_process(msr->r_tsk);
625 smp_mb();
626 msr->r_msg = msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700627
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628 return 1;
629 }
630 }
631 }
632 return 0;
633}
634
suzuki651971c2006-12-06 20:37:48 -0800635long do_msgsnd(int msqid, long mtype, void __user *mtext,
636 size_t msgsz, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637{
638 struct msg_queue *msq;
639 struct msg_msg *msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 int err;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700641 struct ipc_namespace *ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700642
Kirill Korotaev1e786932006-10-02 02:18:21 -0700643 ns = current->nsproxy->ipc_ns;
644
645 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 if (mtype < 1)
648 return -EINVAL;
649
suzuki651971c2006-12-06 20:37:48 -0800650 msg = load_msg(mtext, msgsz);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700651 if (IS_ERR(msg))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 return PTR_ERR(msg);
653
654 msg->m_type = mtype;
655 msg->m_ts = msgsz;
656
Nadia Derbey023a5352007-10-18 23:40:51 -0700657 msq = msg_lock_check(ns, msqid);
658 if (IS_ERR(msq)) {
659 err = PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 goto out_free;
Nadia Derbey023a5352007-10-18 23:40:51 -0700661 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662
663 for (;;) {
664 struct msg_sender s;
665
Ingo Molnar5a06a362006-07-30 03:04:11 -0700666 err = -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 if (ipcperms(&msq->q_perm, S_IWUGO))
668 goto out_unlock_free;
669
670 err = security_msg_queue_msgsnd(msq, msg, msgflg);
671 if (err)
672 goto out_unlock_free;
673
Ingo Molnar5a06a362006-07-30 03:04:11 -0700674 if (msgsz + msq->q_cbytes <= msq->q_qbytes &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 1 + msq->q_qnum <= msq->q_qbytes) {
676 break;
677 }
678
679 /* queue full, wait: */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700680 if (msgflg & IPC_NOWAIT) {
681 err = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682 goto out_unlock_free;
683 }
684 ss_add(msq, &s);
685 ipc_rcu_getref(msq);
686 msg_unlock(msq);
687 schedule();
688
689 ipc_lock_by_ptr(&msq->q_perm);
690 ipc_rcu_putref(msq);
691 if (msq->q_perm.deleted) {
692 err = -EIDRM;
693 goto out_unlock_free;
694 }
695 ss_del(&s);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700696
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 if (signal_pending(current)) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700698 err = -ERESTARTNOHAND;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 goto out_unlock_free;
700 }
701 }
702
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700703 msq->q_lspid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 msq->q_stime = get_seconds();
705
Ingo Molnar5a06a362006-07-30 03:04:11 -0700706 if (!pipelined_send(msq, msg)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 /* noone is waiting for this message, enqueue it */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700708 list_add_tail(&msg->m_list, &msq->q_messages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 msq->q_cbytes += msgsz;
710 msq->q_qnum++;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700711 atomic_add(msgsz, &ns->msg_bytes);
712 atomic_inc(&ns->msg_hdrs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700714
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 err = 0;
716 msg = NULL;
717
718out_unlock_free:
719 msg_unlock(msq);
720out_free:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700721 if (msg != NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 free_msg(msg);
723 return err;
724}
725
suzuki651971c2006-12-06 20:37:48 -0800726asmlinkage long
727sys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, int msgflg)
728{
729 long mtype;
730
731 if (get_user(mtype, &msgp->mtype))
732 return -EFAULT;
733 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
734}
735
Ingo Molnar5a06a362006-07-30 03:04:11 -0700736static inline int convert_mode(long *msgtyp, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700738 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 * find message of correct type.
740 * msgtyp = 0 => get first.
741 * msgtyp > 0 => get first message of matching type.
Ingo Molnar5a06a362006-07-30 03:04:11 -0700742 * msgtyp < 0 => get message with least type must be < abs(msgtype).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700744 if (*msgtyp == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 return SEARCH_ANY;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700746 if (*msgtyp < 0) {
747 *msgtyp = -*msgtyp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 return SEARCH_LESSEQUAL;
749 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700750 if (msgflg & MSG_EXCEPT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 return SEARCH_NOTEQUAL;
752 return SEARCH_EQUAL;
753}
754
suzuki651971c2006-12-06 20:37:48 -0800755long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
756 size_t msgsz, long msgtyp, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757{
758 struct msg_queue *msq;
759 struct msg_msg *msg;
760 int mode;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700761 struct ipc_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762
763 if (msqid < 0 || (long) msgsz < 0)
764 return -EINVAL;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700765 mode = convert_mode(&msgtyp, msgflg);
Kirill Korotaev1e786932006-10-02 02:18:21 -0700766 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767
Nadia Derbey023a5352007-10-18 23:40:51 -0700768 msq = msg_lock_check(ns, msqid);
769 if (IS_ERR(msq))
770 return PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771
772 for (;;) {
773 struct msg_receiver msr_d;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700774 struct list_head *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775
776 msg = ERR_PTR(-EACCES);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700777 if (ipcperms(&msq->q_perm, S_IRUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 goto out_unlock;
779
780 msg = ERR_PTR(-EAGAIN);
781 tmp = msq->q_messages.next;
782 while (tmp != &msq->q_messages) {
783 struct msg_msg *walk_msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700784
785 walk_msg = list_entry(tmp, struct msg_msg, m_list);
786 if (testmsg(walk_msg, msgtyp, mode) &&
787 !security_msg_queue_msgrcv(msq, walk_msg, current,
788 msgtyp, mode)) {
789
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 msg = walk_msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700791 if (mode == SEARCH_LESSEQUAL &&
792 walk_msg->m_type != 1) {
793 msg = walk_msg;
794 msgtyp = walk_msg->m_type - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 } else {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700796 msg = walk_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 break;
798 }
799 }
800 tmp = tmp->next;
801 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700802 if (!IS_ERR(msg)) {
803 /*
804 * Found a suitable message.
805 * Unlink it from the queue.
806 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
808 msg = ERR_PTR(-E2BIG);
809 goto out_unlock;
810 }
811 list_del(&msg->m_list);
812 msq->q_qnum--;
813 msq->q_rtime = get_seconds();
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700814 msq->q_lrpid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 msq->q_cbytes -= msg->m_ts;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700816 atomic_sub(msg->m_ts, &ns->msg_bytes);
817 atomic_dec(&ns->msg_hdrs);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700818 ss_wakeup(&msq->q_senders, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819 msg_unlock(msq);
820 break;
821 }
822 /* No message waiting. Wait for a message */
823 if (msgflg & IPC_NOWAIT) {
824 msg = ERR_PTR(-ENOMSG);
825 goto out_unlock;
826 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700827 list_add_tail(&msr_d.r_list, &msq->q_receivers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 msr_d.r_tsk = current;
829 msr_d.r_msgtype = msgtyp;
830 msr_d.r_mode = mode;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700831 if (msgflg & MSG_NOERROR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 msr_d.r_maxsize = INT_MAX;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700833 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 msr_d.r_maxsize = msgsz;
835 msr_d.r_msg = ERR_PTR(-EAGAIN);
836 current->state = TASK_INTERRUPTIBLE;
837 msg_unlock(msq);
838
839 schedule();
840
841 /* Lockless receive, part 1:
842 * Disable preemption. We don't hold a reference to the queue
843 * and getting a reference would defeat the idea of a lockless
844 * operation, thus the code relies on rcu to guarantee the
845 * existance of msq:
846 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
847 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
848 * rcu_read_lock() prevents preemption between reading r_msg
849 * and the spin_lock() inside ipc_lock_by_ptr().
850 */
851 rcu_read_lock();
852
853 /* Lockless receive, part 2:
854 * Wait until pipelined_send or expunge_all are outside of
855 * wake_up_process(). There is a race with exit(), see
856 * ipc/mqueue.c for the details.
857 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700858 msg = (struct msg_msg*)msr_d.r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 while (msg == NULL) {
860 cpu_relax();
Ingo Molnar5a06a362006-07-30 03:04:11 -0700861 msg = (struct msg_msg *)msr_d.r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 }
863
864 /* Lockless receive, part 3:
865 * If there is a message or an error then accept it without
866 * locking.
867 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700868 if (msg != ERR_PTR(-EAGAIN)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869 rcu_read_unlock();
870 break;
871 }
872
873 /* Lockless receive, part 3:
874 * Acquire the queue spinlock.
875 */
876 ipc_lock_by_ptr(&msq->q_perm);
877 rcu_read_unlock();
878
879 /* Lockless receive, part 4:
880 * Repeat test after acquiring the spinlock.
881 */
882 msg = (struct msg_msg*)msr_d.r_msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700883 if (msg != ERR_PTR(-EAGAIN))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 goto out_unlock;
885
886 list_del(&msr_d.r_list);
887 if (signal_pending(current)) {
888 msg = ERR_PTR(-ERESTARTNOHAND);
889out_unlock:
890 msg_unlock(msq);
891 break;
892 }
893 }
894 if (IS_ERR(msg))
Ingo Molnar5a06a362006-07-30 03:04:11 -0700895 return PTR_ERR(msg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896
897 msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz;
suzuki651971c2006-12-06 20:37:48 -0800898 *pmtype = msg->m_type;
899 if (store_msg(mtext, msg, msgsz))
Ingo Molnar5a06a362006-07-30 03:04:11 -0700900 msgsz = -EFAULT;
suzuki651971c2006-12-06 20:37:48 -0800901
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 free_msg(msg);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700903
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904 return msgsz;
905}
906
suzuki651971c2006-12-06 20:37:48 -0800907asmlinkage long sys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
908 long msgtyp, int msgflg)
909{
910 long err, mtype;
911
912 err = do_msgrcv(msqid, &mtype, msgp->mtext, msgsz, msgtyp, msgflg);
913 if (err < 0)
914 goto out;
915
916 if (put_user(mtype, &msgp->mtype))
917 err = -EFAULT;
918out:
919 return err;
920}
921
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -0700923static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924{
Mike Waychison19b49462005-09-06 15:17:10 -0700925 struct msg_queue *msq = it;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926
Mike Waychison19b49462005-09-06 15:17:10 -0700927 return seq_printf(s,
Ingo Molnar5a06a362006-07-30 03:04:11 -0700928 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
929 msq->q_perm.key,
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700930 msq->q_perm.id,
Ingo Molnar5a06a362006-07-30 03:04:11 -0700931 msq->q_perm.mode,
932 msq->q_cbytes,
933 msq->q_qnum,
934 msq->q_lspid,
935 msq->q_lrpid,
936 msq->q_perm.uid,
937 msq->q_perm.gid,
938 msq->q_perm.cuid,
939 msq->q_perm.cgid,
940 msq->q_stime,
941 msq->q_rtime,
942 msq->q_ctime);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943}
944#endif