blob: ccf5f495db7b851cb4ae92d40acad93919b25a49 [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/slab.h>
27#include <linux/msg.h>
28#include <linux/spinlock.h>
29#include <linux/init.h>
30#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>
Ingo Molnar5f921ae2006-03-26 01:37:17 -080039
Linus Torvalds1da177e2005-04-16 15:20:36 -070040#include <asm/current.h>
41#include <asm/uaccess.h>
42#include "util.h"
43
Ingo Molnar5a06a362006-07-30 03:04:11 -070044/*
45 * one msg_receiver structure for each sleeping receiver:
46 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070047struct msg_receiver {
Ingo Molnar5a06a362006-07-30 03:04:11 -070048 struct list_head r_list;
49 struct task_struct *r_tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
Ingo Molnar5a06a362006-07-30 03:04:11 -070051 int r_mode;
52 long r_msgtype;
53 long r_maxsize;
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
Linus Torvalds80491eb2006-11-04 09:55:00 -080055 struct msg_msg *volatile r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056};
57
58/* one msg_sender for each sleeping sender */
59struct msg_sender {
Ingo Molnar5a06a362006-07-30 03:04:11 -070060 struct list_head list;
61 struct task_struct *tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062};
63
64#define SEARCH_ANY 1
65#define SEARCH_EQUAL 2
66#define SEARCH_NOTEQUAL 3
67#define SEARCH_LESSEQUAL 4
68
Kirill Korotaev1e786932006-10-02 02:18:21 -070069static struct ipc_ids init_msg_ids;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
Kirill Korotaev1e786932006-10-02 02:18:21 -070071#define msg_ids(ns) (*((ns)->ids[IPC_MSG_IDS]))
72
Ingo Molnar5a06a362006-07-30 03:04:11 -070073#define msg_unlock(msq) ipc_unlock(&(msq)->q_perm)
Nadia Derbey1b531f22007-10-18 23:40:55 -070074#define msg_buildid(id, seq) ipc_buildid(id, seq)
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
Nadia Derbey7ca7e562007-10-18 23:40:48 -070076static void freeque(struct ipc_namespace *, struct msg_queue *);
Nadia Derbey7748dbf2007-10-18 23:40:49 -070077static int newque(struct ipc_namespace *, struct ipc_params *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -070079static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080#endif
81
Cedric Le Goater7d69a1f2007-07-15 23:40:58 -070082static void __msg_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
Linus Torvalds1da177e2005-04-16 15:20:36 -070083{
Kirill Korotaev1e786932006-10-02 02:18:21 -070084 ns->ids[IPC_MSG_IDS] = ids;
85 ns->msg_ctlmax = MSGMAX;
86 ns->msg_ctlmnb = MSGMNB;
87 ns->msg_ctlmni = MSGMNI;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -070088 atomic_set(&ns->msg_bytes, 0);
89 atomic_set(&ns->msg_hdrs, 0);
Nadia Derbey7ca7e562007-10-18 23:40:48 -070090 ipc_init_ids(ids);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091}
92
Kirill Korotaev1e786932006-10-02 02:18:21 -070093int msg_init_ns(struct ipc_namespace *ns)
94{
95 struct ipc_ids *ids;
96
97 ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
98 if (ids == NULL)
99 return -ENOMEM;
100
101 __msg_init_ns(ns, ids);
102 return 0;
103}
104
105void msg_exit_ns(struct ipc_namespace *ns)
106{
Kirill Korotaev1e786932006-10-02 02:18:21 -0700107 struct msg_queue *msq;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700108 int next_id;
109 int total, in_use;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700110
Nadia Derbey3e148c72007-10-18 23:40:54 -0700111 down_write(&msg_ids(ns).rw_mutex);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700112
113 in_use = msg_ids(ns).in_use;
114
115 for (total = 0, next_id = 0; total < in_use; next_id++) {
116 msq = idr_find(&msg_ids(ns).ipcs_idr, next_id);
Kirill Korotaev1e786932006-10-02 02:18:21 -0700117 if (msq == NULL)
118 continue;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700119 ipc_lock_by_ptr(&msq->q_perm);
120 freeque(ns, msq);
121 total++;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700122 }
Nadia Derbey3e148c72007-10-18 23:40:54 -0700123
124 up_write(&msg_ids(ns).rw_mutex);
Kirill Korotaev1e786932006-10-02 02:18:21 -0700125
126 kfree(ns->ids[IPC_MSG_IDS]);
127 ns->ids[IPC_MSG_IDS] = NULL;
128}
Kirill Korotaev1e786932006-10-02 02:18:21 -0700129
130void __init msg_init(void)
131{
132 __msg_init_ns(&init_ipc_ns, &init_msg_ids);
133 ipc_init_proc_interface("sysvipc/msg",
134 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
135 IPC_MSG_IDS, sysvipc_msg_proc_show);
136}
137
Nadia Derbey3e148c72007-10-18 23:40:54 -0700138/*
139 * This routine is called in the paths where the rw_mutex is held to protect
140 * access to the idr tree.
141 */
142static inline struct msg_queue *msg_lock_check_down(struct ipc_namespace *ns,
143 int id)
144{
145 struct kern_ipc_perm *ipcp = ipc_lock_check_down(&msg_ids(ns), id);
146
147 return container_of(ipcp, struct msg_queue, q_perm);
148}
149
150/*
151 * msg_lock_(check_) routines are called in the paths where the rw_mutex
152 * is not held.
153 */
Nadia Derbey023a5352007-10-18 23:40:51 -0700154static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id)
155{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700156 struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id);
157
158 return container_of(ipcp, struct msg_queue, q_perm);
Nadia Derbey023a5352007-10-18 23:40:51 -0700159}
160
161static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns,
162 int id)
163{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700164 struct kern_ipc_perm *ipcp = ipc_lock_check(&msg_ids(ns), id);
165
166 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);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700206 if (id == -1) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 security_msg_queue_free(msq);
208 ipc_rcu_putref(msq);
209 return -ENOSPC;
210 }
211
Nadia Derbey1b531f22007-10-18 23:40:55 -0700212 msq->q_perm.id = msg_buildid(id, msq->q_perm.seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 msq->q_stime = msq->q_rtime = 0;
214 msq->q_ctime = get_seconds();
215 msq->q_cbytes = msq->q_qnum = 0;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700216 msq->q_qbytes = ns->msg_ctlmnb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 msq->q_lspid = msq->q_lrpid = 0;
218 INIT_LIST_HEAD(&msq->q_messages);
219 INIT_LIST_HEAD(&msq->q_receivers);
220 INIT_LIST_HEAD(&msq->q_senders);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700221
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 msg_unlock(msq);
223
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700224 return msq->q_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225}
226
Ingo Molnar5a06a362006-07-30 03:04:11 -0700227static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700229 mss->tsk = current;
230 current->state = TASK_INTERRUPTIBLE;
231 list_add_tail(&mss->list, &msq->q_senders);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232}
233
Ingo Molnar5a06a362006-07-30 03:04:11 -0700234static inline void ss_del(struct msg_sender *mss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700236 if (mss->list.next != NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 list_del(&mss->list);
238}
239
Ingo Molnar5a06a362006-07-30 03:04:11 -0700240static void ss_wakeup(struct list_head *h, int kill)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241{
242 struct list_head *tmp;
243
244 tmp = h->next;
245 while (tmp != h) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700246 struct msg_sender *mss;
247
248 mss = list_entry(tmp, struct msg_sender, list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 tmp = tmp->next;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700250 if (kill)
251 mss->list.next = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 wake_up_process(mss->tsk);
253 }
254}
255
Ingo Molnar5a06a362006-07-30 03:04:11 -0700256static void expunge_all(struct msg_queue *msq, int res)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257{
258 struct list_head *tmp;
259
260 tmp = msq->q_receivers.next;
261 while (tmp != &msq->q_receivers) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700262 struct msg_receiver *msr;
263
264 msr = list_entry(tmp, struct msg_receiver, r_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 tmp = tmp->next;
266 msr->r_msg = NULL;
267 wake_up_process(msr->r_tsk);
268 smp_mb();
269 msr->r_msg = ERR_PTR(res);
270 }
271}
Ingo Molnar5a06a362006-07-30 03:04:11 -0700272
273/*
274 * freeque() wakes up waiters on the sender and receiver waiting queue,
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700275 * removes the message queue from message queue ID IDR, and cleans up all the
276 * messages associated with this queue.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 *
Nadia Derbey3e148c72007-10-18 23:40:54 -0700278 * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held
279 * before freeque() is called. msg_ids.rw_mutex remains locked on exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700281static void freeque(struct ipc_namespace *ns, struct msg_queue *msq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282{
283 struct list_head *tmp;
284
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
Ingo Molnar5a06a362006-07-30 03:04:11 -0700313asmlinkage long sys_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
Ingo Molnar5a06a362006-07-30 03:04:11 -0700349 if (in->msg_cbytes > USHRT_MAX)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 out.msg_cbytes = USHRT_MAX;
351 else
352 out.msg_cbytes = in->msg_cbytes;
353 out.msg_lcbytes = in->msg_cbytes;
354
Ingo Molnar5a06a362006-07-30 03:04:11 -0700355 if (in->msg_qnum > USHRT_MAX)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 out.msg_qnum = USHRT_MAX;
357 else
358 out.msg_qnum = in->msg_qnum;
359
Ingo Molnar5a06a362006-07-30 03:04:11 -0700360 if (in->msg_qbytes > USHRT_MAX)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 out.msg_qbytes = USHRT_MAX;
362 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
376struct msq_setbuf {
377 unsigned long qbytes;
378 uid_t uid;
379 gid_t gid;
380 mode_t mode;
381};
382
Ingo Molnar5a06a362006-07-30 03:04:11 -0700383static inline unsigned long
384copy_msqid_from_user(struct msq_setbuf *out, void __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385{
386 switch(version) {
387 case IPC_64:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700388 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 struct msqid64_ds tbuf;
390
Ingo Molnar5a06a362006-07-30 03:04:11 -0700391 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 return -EFAULT;
393
394 out->qbytes = tbuf.msg_qbytes;
395 out->uid = tbuf.msg_perm.uid;
396 out->gid = tbuf.msg_perm.gid;
397 out->mode = tbuf.msg_perm.mode;
398
399 return 0;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700400 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 case IPC_OLD:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700402 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 struct msqid_ds tbuf_old;
404
Ingo Molnar5a06a362006-07-30 03:04:11 -0700405 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 return -EFAULT;
407
408 out->uid = tbuf_old.msg_perm.uid;
409 out->gid = tbuf_old.msg_perm.gid;
410 out->mode = tbuf_old.msg_perm.mode;
411
Ingo Molnar5a06a362006-07-30 03:04:11 -0700412 if (tbuf_old.msg_qbytes == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 out->qbytes = tbuf_old.msg_lqbytes;
414 else
415 out->qbytes = tbuf_old.msg_qbytes;
416
417 return 0;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700418 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 default:
420 return -EINVAL;
421 }
422}
423
Ingo Molnar5a06a362006-07-30 03:04:11 -0700424asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 struct kern_ipc_perm *ipcp;
Jeff Garzik8e1c0912007-07-17 05:40:59 -0400427 struct msq_setbuf uninitialized_var(setbuf);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700428 struct msg_queue *msq;
429 int err, version;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700430 struct ipc_namespace *ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700431
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 if (msqid < 0 || cmd < 0)
433 return -EINVAL;
434
435 version = ipc_parse_version(&cmd);
Kirill Korotaev1e786932006-10-02 02:18:21 -0700436 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437
438 switch (cmd) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700439 case IPC_INFO:
440 case MSG_INFO:
441 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 struct msginfo msginfo;
443 int max_id;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700444
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 if (!buf)
446 return -EFAULT;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700447 /*
448 * We must not return kernel stack data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 * due to padding, it's not enough
450 * to set all member fields.
451 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 err = security_msg_queue_msgctl(NULL, cmd);
453 if (err)
454 return err;
455
Ingo Molnar5a06a362006-07-30 03:04:11 -0700456 memset(&msginfo, 0, sizeof(msginfo));
Kirill Korotaev1e786932006-10-02 02:18:21 -0700457 msginfo.msgmni = ns->msg_ctlmni;
458 msginfo.msgmax = ns->msg_ctlmax;
459 msginfo.msgmnb = ns->msg_ctlmnb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 msginfo.msgssz = MSGSSZ;
461 msginfo.msgseg = MSGSEG;
Nadia Derbey3e148c72007-10-18 23:40:54 -0700462 down_read(&msg_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 if (cmd == MSG_INFO) {
Kirill Korotaev1e786932006-10-02 02:18:21 -0700464 msginfo.msgpool = msg_ids(ns).in_use;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700465 msginfo.msgmap = atomic_read(&ns->msg_hdrs);
466 msginfo.msgtql = atomic_read(&ns->msg_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 } else {
468 msginfo.msgmap = MSGMAP;
469 msginfo.msgpool = MSGPOOL;
470 msginfo.msgtql = MSGTQL;
471 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700472 max_id = ipc_get_maxid(&msg_ids(ns));
Nadia Derbey3e148c72007-10-18 23:40:54 -0700473 up_read(&msg_ids(ns).rw_mutex);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700474 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 return -EFAULT;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700476 return (max_id < 0) ? 0 : max_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700478 case MSG_STAT: /* msqid is an index rather than a msg queue id */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 case IPC_STAT:
480 {
481 struct msqid64_ds tbuf;
482 int success_return;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700483
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 if (!buf)
485 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486
Ingo Molnar5a06a362006-07-30 03:04:11 -0700487 if (cmd == MSG_STAT) {
Nadia Derbey023a5352007-10-18 23:40:51 -0700488 msq = msg_lock(ns, msqid);
489 if (IS_ERR(msq))
490 return PTR_ERR(msq);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700491 success_return = msq->q_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 } else {
Nadia Derbey023a5352007-10-18 23:40:51 -0700493 msq = msg_lock_check(ns, msqid);
494 if (IS_ERR(msq))
495 return PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 success_return = 0;
497 }
498 err = -EACCES;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700499 if (ipcperms(&msq->q_perm, S_IRUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 goto out_unlock;
501
502 err = security_msg_queue_msgctl(msq, cmd);
503 if (err)
504 goto out_unlock;
505
Nadia Derbey023a5352007-10-18 23:40:51 -0700506 memset(&tbuf, 0, sizeof(tbuf));
507
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
509 tbuf.msg_stime = msq->q_stime;
510 tbuf.msg_rtime = msq->q_rtime;
511 tbuf.msg_ctime = msq->q_ctime;
512 tbuf.msg_cbytes = msq->q_cbytes;
513 tbuf.msg_qnum = msq->q_qnum;
514 tbuf.msg_qbytes = msq->q_qbytes;
515 tbuf.msg_lspid = msq->q_lspid;
516 tbuf.msg_lrpid = msq->q_lrpid;
517 msg_unlock(msq);
518 if (copy_msqid_to_user(buf, &tbuf, version))
519 return -EFAULT;
520 return success_return;
521 }
522 case IPC_SET:
523 if (!buf)
524 return -EFAULT;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700525 if (copy_msqid_from_user(&setbuf, buf, version))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 break;
528 case IPC_RMID:
529 break;
530 default:
531 return -EINVAL;
532 }
533
Nadia Derbey3e148c72007-10-18 23:40:54 -0700534 down_write(&msg_ids(ns).rw_mutex);
535 msq = msg_lock_check_down(ns, msqid);
Nadia Derbey023a5352007-10-18 23:40:51 -0700536 if (IS_ERR(msq)) {
537 err = PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 goto out_up;
Nadia Derbey023a5352007-10-18 23:40:51 -0700539 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 ipcp = &msq->q_perm;
Steve Grubb073115d2006-04-02 17:07:33 -0400542
543 err = audit_ipc_obj(ipcp);
544 if (err)
545 goto out_unlock_up;
Jeff Garzik8e1c0912007-07-17 05:40:59 -0400546 if (cmd == IPC_SET) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700547 err = audit_ipc_set_perm(setbuf.qbytes, setbuf.uid, setbuf.gid,
548 setbuf.mode);
Linda Knippersac032212006-05-16 22:03:48 -0400549 if (err)
550 goto out_unlock_up;
551 }
Steve Grubb073115d2006-04-02 17:07:33 -0400552
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 err = -EPERM;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700554 if (current->euid != ipcp->cuid &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN))
Ingo Molnar5a06a362006-07-30 03:04:11 -0700556 /* We _could_ check for CAP_CHOWN above, but we don't */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 goto out_unlock_up;
558
559 err = security_msg_queue_msgctl(msq, cmd);
560 if (err)
561 goto out_unlock_up;
562
563 switch (cmd) {
564 case IPC_SET:
565 {
566 err = -EPERM;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700567 if (setbuf.qbytes > ns->msg_ctlmnb && !capable(CAP_SYS_RESOURCE))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 goto out_unlock_up;
569
570 msq->q_qbytes = setbuf.qbytes;
571
572 ipcp->uid = setbuf.uid;
573 ipcp->gid = setbuf.gid;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700574 ipcp->mode = (ipcp->mode & ~S_IRWXUGO) |
575 (S_IRWXUGO & setbuf.mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 msq->q_ctime = get_seconds();
577 /* sleeping receivers might be excluded by
578 * stricter permissions.
579 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700580 expunge_all(msq, -EAGAIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 /* sleeping senders might be able to send
582 * due to a larger queue size.
583 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700584 ss_wakeup(&msq->q_senders, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 msg_unlock(msq);
586 break;
587 }
588 case IPC_RMID:
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700589 freeque(ns, msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 break;
591 }
592 err = 0;
593out_up:
Nadia Derbey3e148c72007-10-18 23:40:54 -0700594 up_write(&msg_ids(ns).rw_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 return err;
596out_unlock_up:
597 msg_unlock(msq);
598 goto out_up;
599out_unlock:
600 msg_unlock(msq);
601 return err;
602}
603
Ingo Molnar5a06a362006-07-30 03:04:11 -0700604static int testmsg(struct msg_msg *msg, long type, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605{
606 switch(mode)
607 {
608 case SEARCH_ANY:
609 return 1;
610 case SEARCH_LESSEQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700611 if (msg->m_type <=type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 return 1;
613 break;
614 case SEARCH_EQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700615 if (msg->m_type == type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 return 1;
617 break;
618 case SEARCH_NOTEQUAL:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700619 if (msg->m_type != type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 return 1;
621 break;
622 }
623 return 0;
624}
625
Ingo Molnar5a06a362006-07-30 03:04:11 -0700626static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700628 struct list_head *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629
630 tmp = msq->q_receivers.next;
631 while (tmp != &msq->q_receivers) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700632 struct msg_receiver *msr;
633
634 msr = list_entry(tmp, struct msg_receiver, r_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 tmp = tmp->next;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700636 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
637 !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
638 msr->r_msgtype, msr->r_mode)) {
639
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 list_del(&msr->r_list);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700641 if (msr->r_maxsize < msg->m_ts) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 msr->r_msg = NULL;
643 wake_up_process(msr->r_tsk);
644 smp_mb();
645 msr->r_msg = ERR_PTR(-E2BIG);
646 } else {
647 msr->r_msg = NULL;
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700648 msq->q_lrpid = task_pid_vnr(msr->r_tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 msq->q_rtime = get_seconds();
650 wake_up_process(msr->r_tsk);
651 smp_mb();
652 msr->r_msg = msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700653
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 return 1;
655 }
656 }
657 }
658 return 0;
659}
660
suzuki651971c2006-12-06 20:37:48 -0800661long do_msgsnd(int msqid, long mtype, void __user *mtext,
662 size_t msgsz, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663{
664 struct msg_queue *msq;
665 struct msg_msg *msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 int err;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700667 struct ipc_namespace *ns;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700668
Kirill Korotaev1e786932006-10-02 02:18:21 -0700669 ns = current->nsproxy->ipc_ns;
670
671 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 if (mtype < 1)
674 return -EINVAL;
675
suzuki651971c2006-12-06 20:37:48 -0800676 msg = load_msg(mtext, msgsz);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700677 if (IS_ERR(msg))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 return PTR_ERR(msg);
679
680 msg->m_type = mtype;
681 msg->m_ts = msgsz;
682
Nadia Derbey023a5352007-10-18 23:40:51 -0700683 msq = msg_lock_check(ns, msqid);
684 if (IS_ERR(msq)) {
685 err = PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 goto out_free;
Nadia Derbey023a5352007-10-18 23:40:51 -0700687 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688
689 for (;;) {
690 struct msg_sender s;
691
Ingo Molnar5a06a362006-07-30 03:04:11 -0700692 err = -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 if (ipcperms(&msq->q_perm, S_IWUGO))
694 goto out_unlock_free;
695
696 err = security_msg_queue_msgsnd(msq, msg, msgflg);
697 if (err)
698 goto out_unlock_free;
699
Ingo Molnar5a06a362006-07-30 03:04:11 -0700700 if (msgsz + msq->q_cbytes <= msq->q_qbytes &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 1 + msq->q_qnum <= msq->q_qbytes) {
702 break;
703 }
704
705 /* queue full, wait: */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700706 if (msgflg & IPC_NOWAIT) {
707 err = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 goto out_unlock_free;
709 }
710 ss_add(msq, &s);
711 ipc_rcu_getref(msq);
712 msg_unlock(msq);
713 schedule();
714
715 ipc_lock_by_ptr(&msq->q_perm);
716 ipc_rcu_putref(msq);
717 if (msq->q_perm.deleted) {
718 err = -EIDRM;
719 goto out_unlock_free;
720 }
721 ss_del(&s);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700722
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 if (signal_pending(current)) {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700724 err = -ERESTARTNOHAND;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 goto out_unlock_free;
726 }
727 }
728
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700729 msq->q_lspid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 msq->q_stime = get_seconds();
731
Ingo Molnar5a06a362006-07-30 03:04:11 -0700732 if (!pipelined_send(msq, msg)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 /* noone is waiting for this message, enqueue it */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700734 list_add_tail(&msg->m_list, &msq->q_messages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 msq->q_cbytes += msgsz;
736 msq->q_qnum++;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700737 atomic_add(msgsz, &ns->msg_bytes);
738 atomic_inc(&ns->msg_hdrs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700740
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 err = 0;
742 msg = NULL;
743
744out_unlock_free:
745 msg_unlock(msq);
746out_free:
Ingo Molnar5a06a362006-07-30 03:04:11 -0700747 if (msg != NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 free_msg(msg);
749 return err;
750}
751
suzuki651971c2006-12-06 20:37:48 -0800752asmlinkage long
753sys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, int msgflg)
754{
755 long mtype;
756
757 if (get_user(mtype, &msgp->mtype))
758 return -EFAULT;
759 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
760}
761
Ingo Molnar5a06a362006-07-30 03:04:11 -0700762static inline int convert_mode(long *msgtyp, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763{
Ingo Molnar5a06a362006-07-30 03:04:11 -0700764 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 * find message of correct type.
766 * msgtyp = 0 => get first.
767 * msgtyp > 0 => get first message of matching type.
Ingo Molnar5a06a362006-07-30 03:04:11 -0700768 * msgtyp < 0 => get message with least type must be < abs(msgtype).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700770 if (*msgtyp == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 return SEARCH_ANY;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700772 if (*msgtyp < 0) {
773 *msgtyp = -*msgtyp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 return SEARCH_LESSEQUAL;
775 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700776 if (msgflg & MSG_EXCEPT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 return SEARCH_NOTEQUAL;
778 return SEARCH_EQUAL;
779}
780
suzuki651971c2006-12-06 20:37:48 -0800781long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
782 size_t msgsz, long msgtyp, int msgflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783{
784 struct msg_queue *msq;
785 struct msg_msg *msg;
786 int mode;
Kirill Korotaev1e786932006-10-02 02:18:21 -0700787 struct ipc_namespace *ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788
789 if (msqid < 0 || (long) msgsz < 0)
790 return -EINVAL;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700791 mode = convert_mode(&msgtyp, msgflg);
Kirill Korotaev1e786932006-10-02 02:18:21 -0700792 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793
Nadia Derbey023a5352007-10-18 23:40:51 -0700794 msq = msg_lock_check(ns, msqid);
795 if (IS_ERR(msq))
796 return PTR_ERR(msq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797
798 for (;;) {
799 struct msg_receiver msr_d;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700800 struct list_head *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801
802 msg = ERR_PTR(-EACCES);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700803 if (ipcperms(&msq->q_perm, S_IRUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 goto out_unlock;
805
806 msg = ERR_PTR(-EAGAIN);
807 tmp = msq->q_messages.next;
808 while (tmp != &msq->q_messages) {
809 struct msg_msg *walk_msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700810
811 walk_msg = list_entry(tmp, struct msg_msg, m_list);
812 if (testmsg(walk_msg, msgtyp, mode) &&
813 !security_msg_queue_msgrcv(msq, walk_msg, current,
814 msgtyp, mode)) {
815
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 msg = walk_msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700817 if (mode == SEARCH_LESSEQUAL &&
818 walk_msg->m_type != 1) {
819 msg = walk_msg;
820 msgtyp = walk_msg->m_type - 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 } else {
Ingo Molnar5a06a362006-07-30 03:04:11 -0700822 msg = walk_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 break;
824 }
825 }
826 tmp = tmp->next;
827 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700828 if (!IS_ERR(msg)) {
829 /*
830 * Found a suitable message.
831 * Unlink it from the queue.
832 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
834 msg = ERR_PTR(-E2BIG);
835 goto out_unlock;
836 }
837 list_del(&msg->m_list);
838 msq->q_qnum--;
839 msq->q_rtime = get_seconds();
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700840 msq->q_lrpid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 msq->q_cbytes -= msg->m_ts;
Kirill Korotaev3ac88a42007-10-18 23:40:56 -0700842 atomic_sub(msg->m_ts, &ns->msg_bytes);
843 atomic_dec(&ns->msg_hdrs);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700844 ss_wakeup(&msq->q_senders, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 msg_unlock(msq);
846 break;
847 }
848 /* No message waiting. Wait for a message */
849 if (msgflg & IPC_NOWAIT) {
850 msg = ERR_PTR(-ENOMSG);
851 goto out_unlock;
852 }
Ingo Molnar5a06a362006-07-30 03:04:11 -0700853 list_add_tail(&msr_d.r_list, &msq->q_receivers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 msr_d.r_tsk = current;
855 msr_d.r_msgtype = msgtyp;
856 msr_d.r_mode = mode;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700857 if (msgflg & MSG_NOERROR)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 msr_d.r_maxsize = INT_MAX;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700859 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860 msr_d.r_maxsize = msgsz;
861 msr_d.r_msg = ERR_PTR(-EAGAIN);
862 current->state = TASK_INTERRUPTIBLE;
863 msg_unlock(msq);
864
865 schedule();
866
867 /* Lockless receive, part 1:
868 * Disable preemption. We don't hold a reference to the queue
869 * and getting a reference would defeat the idea of a lockless
870 * operation, thus the code relies on rcu to guarantee the
871 * existance of msq:
872 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
873 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
874 * rcu_read_lock() prevents preemption between reading r_msg
875 * and the spin_lock() inside ipc_lock_by_ptr().
876 */
877 rcu_read_lock();
878
879 /* Lockless receive, part 2:
880 * Wait until pipelined_send or expunge_all are outside of
881 * wake_up_process(). There is a race with exit(), see
882 * ipc/mqueue.c for the details.
883 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700884 msg = (struct msg_msg*)msr_d.r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 while (msg == NULL) {
886 cpu_relax();
Ingo Molnar5a06a362006-07-30 03:04:11 -0700887 msg = (struct msg_msg *)msr_d.r_msg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 }
889
890 /* Lockless receive, part 3:
891 * If there is a message or an error then accept it without
892 * locking.
893 */
Ingo Molnar5a06a362006-07-30 03:04:11 -0700894 if (msg != ERR_PTR(-EAGAIN)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 rcu_read_unlock();
896 break;
897 }
898
899 /* Lockless receive, part 3:
900 * Acquire the queue spinlock.
901 */
902 ipc_lock_by_ptr(&msq->q_perm);
903 rcu_read_unlock();
904
905 /* Lockless receive, part 4:
906 * Repeat test after acquiring the spinlock.
907 */
908 msg = (struct msg_msg*)msr_d.r_msg;
Ingo Molnar5a06a362006-07-30 03:04:11 -0700909 if (msg != ERR_PTR(-EAGAIN))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 goto out_unlock;
911
912 list_del(&msr_d.r_list);
913 if (signal_pending(current)) {
914 msg = ERR_PTR(-ERESTARTNOHAND);
915out_unlock:
916 msg_unlock(msq);
917 break;
918 }
919 }
920 if (IS_ERR(msg))
Ingo Molnar5a06a362006-07-30 03:04:11 -0700921 return PTR_ERR(msg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922
923 msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz;
suzuki651971c2006-12-06 20:37:48 -0800924 *pmtype = msg->m_type;
925 if (store_msg(mtext, msg, msgsz))
Ingo Molnar5a06a362006-07-30 03:04:11 -0700926 msgsz = -EFAULT;
suzuki651971c2006-12-06 20:37:48 -0800927
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928 free_msg(msg);
Ingo Molnar5a06a362006-07-30 03:04:11 -0700929
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 return msgsz;
931}
932
suzuki651971c2006-12-06 20:37:48 -0800933asmlinkage long sys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
934 long msgtyp, int msgflg)
935{
936 long err, mtype;
937
938 err = do_msgrcv(msqid, &mtype, msgp->mtext, msgsz, msgtyp, msgflg);
939 if (err < 0)
940 goto out;
941
942 if (put_user(mtype, &msgp->mtype))
943 err = -EFAULT;
944out:
945 return err;
946}
947
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -0700949static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950{
Mike Waychison19b49462005-09-06 15:17:10 -0700951 struct msg_queue *msq = it;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952
Mike Waychison19b49462005-09-06 15:17:10 -0700953 return seq_printf(s,
Ingo Molnar5a06a362006-07-30 03:04:11 -0700954 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
955 msq->q_perm.key,
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700956 msq->q_perm.id,
Ingo Molnar5a06a362006-07-30 03:04:11 -0700957 msq->q_perm.mode,
958 msq->q_cbytes,
959 msq->q_qnum,
960 msq->q_lspid,
961 msq->q_lrpid,
962 msq->q_perm.uid,
963 msq->q_perm.gid,
964 msq->q_perm.cuid,
965 msq->q_perm.cgid,
966 msq->q_stime,
967 msq->q_rtime,
968 msq->q_ctime);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969}
970#endif