ipc: introduce ipc object locking helpers
[linux-block.git] / ipc / msg.c
CommitLineData
1da177e4
LT
1/*
2 * linux/ipc/msg.c
5a06a363 3 * Copyright (C) 1992 Krishna Balasubramanian
1da177e4
LT
4 *
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
624dffcb 15 * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
073115d6
SG
16 *
17 * support for audit of ipc object properties and permission changes
18 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
1e786937
KK
19 *
20 * namespaces support
21 * OpenVZ, SWsoft Inc.
22 * Pavel Emelianov <xemul@openvz.org>
1da177e4
LT
23 */
24
c59ede7b 25#include <linux/capability.h>
1da177e4
LT
26#include <linux/msg.h>
27#include <linux/spinlock.h>
28#include <linux/init.h>
f7bf3df8 29#include <linux/mm.h>
1da177e4
LT
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>
19b4946c 36#include <linux/seq_file.h>
3e148c79 37#include <linux/rwsem.h>
1e786937 38#include <linux/nsproxy.h>
ae5e1b22 39#include <linux/ipc_namespace.h>
5f921ae9 40
1da177e4
LT
41#include <asm/current.h>
42#include <asm/uaccess.h>
43#include "util.h"
44
5a06a363
IM
45/*
46 * one msg_receiver structure for each sleeping receiver:
47 */
1da177e4 48struct msg_receiver {
5a06a363
IM
49 struct list_head r_list;
50 struct task_struct *r_tsk;
1da177e4 51
5a06a363
IM
52 int r_mode;
53 long r_msgtype;
54 long r_maxsize;
1da177e4 55
80491eb9 56 struct msg_msg *volatile r_msg;
1da177e4
LT
57};
58
59/* one msg_sender for each sleeping sender */
60struct msg_sender {
5a06a363
IM
61 struct list_head list;
62 struct task_struct *tsk;
1da177e4
LT
63};
64
65#define SEARCH_ANY 1
66#define SEARCH_EQUAL 2
67#define SEARCH_NOTEQUAL 3
68#define SEARCH_LESSEQUAL 4
8ac6ed58 69#define SEARCH_NUMBER 5
1da177e4 70
ed2ddbf8 71#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
1da177e4 72
1e786937 73#define msg_unlock(msq) ipc_unlock(&(msq)->q_perm)
1e786937 74
01b8b07a 75static void freeque(struct ipc_namespace *, struct kern_ipc_perm *);
7748dbfa 76static int newque(struct ipc_namespace *, struct ipc_params *);
1da177e4 77#ifdef CONFIG_PROC_FS
19b4946c 78static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
1da177e4
LT
79#endif
80
f7bf3df8
ND
81/*
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.
4d89dc6a
ND
84 * 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.
f7bf3df8 86 */
b6b337ad 87void recompute_msgmni(struct ipc_namespace *ns)
f7bf3df8
ND
88{
89 struct sysinfo i;
90 unsigned long allowed;
4d89dc6a 91 int nb_ns;
f7bf3df8
ND
92
93 si_meminfo(&i);
94 allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit)
95 / MSGMNB;
4d89dc6a
ND
96 nb_ns = atomic_read(&nr_ipc_ns);
97 allowed /= nb_ns;
f7bf3df8
ND
98
99 if (allowed < MSGMNI) {
100 ns->msg_ctlmni = MSGMNI;
dfcceb26 101 return;
f7bf3df8
ND
102 }
103
4d89dc6a
ND
104 if (allowed > IPCMNI / nb_ns) {
105 ns->msg_ctlmni = IPCMNI / nb_ns;
dfcceb26 106 return;
f7bf3df8
ND
107 }
108
109 ns->msg_ctlmni = allowed;
f7bf3df8
ND
110}
111
ed2ddbf8 112void msg_init_ns(struct ipc_namespace *ns)
1e786937 113{
1e786937
KK
114 ns->msg_ctlmax = MSGMAX;
115 ns->msg_ctlmnb = MSGMNB;
f7bf3df8
ND
116
117 recompute_msgmni(ns);
118
3ac88a41
KK
119 atomic_set(&ns->msg_bytes, 0);
120 atomic_set(&ns->msg_hdrs, 0);
ed2ddbf8 121 ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
1e786937
KK
122}
123
ae5e1b22 124#ifdef CONFIG_IPC_NS
1e786937
KK
125void msg_exit_ns(struct ipc_namespace *ns)
126{
01b8b07a 127 free_ipcs(ns, &msg_ids(ns), freeque);
7d6feeb2 128 idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
1e786937 129}
ae5e1b22 130#endif
1e786937 131
5a06a363 132void __init msg_init(void)
1da177e4 133{
ed2ddbf8 134 msg_init_ns(&init_ipc_ns);
dfcceb26
ND
135
136 printk(KERN_INFO "msgmni has been set to %d\n",
137 init_ipc_ns.msg_ctlmni);
138
19b4946c
MW
139 ipc_init_proc_interface("sysvipc/msg",
140 " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
1e786937 141 IPC_MSG_IDS, sysvipc_msg_proc_show);
1da177e4
LT
142}
143
3e148c79
ND
144/*
145 * msg_lock_(check_) routines are called in the paths where the rw_mutex
146 * is not held.
147 */
023a5355
ND
148static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id)
149{
03f02c76
ND
150 struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id);
151
b1ed88b4
PP
152 if (IS_ERR(ipcp))
153 return (struct msg_queue *)ipcp;
154
03f02c76 155 return container_of(ipcp, struct msg_queue, q_perm);
023a5355
ND
156}
157
158static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns,
159 int id)
160{
03f02c76
ND
161 struct kern_ipc_perm *ipcp = ipc_lock_check(&msg_ids(ns), id);
162
b1ed88b4
PP
163 if (IS_ERR(ipcp))
164 return (struct msg_queue *)ipcp;
165
03f02c76 166 return container_of(ipcp, struct msg_queue, q_perm);
023a5355
ND
167}
168
7ca7e564
ND
169static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
170{
171 ipc_rmid(&msg_ids(ns), &s->q_perm);
172}
173
f4566f04
ND
174/**
175 * newque - Create a new msg queue
176 * @ns: namespace
177 * @params: ptr to the structure that contains the key and msgflg
178 *
3e148c79 179 * Called with msg_ids.rw_mutex held (writer)
f4566f04 180 */
7748dbfa 181static int newque(struct ipc_namespace *ns, struct ipc_params *params)
1da177e4 182{
1da177e4 183 struct msg_queue *msq;
5a06a363 184 int id, retval;
7748dbfa
ND
185 key_t key = params->key;
186 int msgflg = params->flg;
1da177e4 187
5a06a363
IM
188 msq = ipc_rcu_alloc(sizeof(*msq));
189 if (!msq)
1da177e4
LT
190 return -ENOMEM;
191
5a06a363 192 msq->q_perm.mode = msgflg & S_IRWXUGO;
1da177e4
LT
193 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
dbfcd91f 202 /* ipc_addid() locks msq upon success. */
1e786937 203 id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
283bb7fa 204 if (id < 0) {
1da177e4
LT
205 security_msg_queue_free(msq);
206 ipc_rcu_putref(msq);
283bb7fa 207 return id;
1da177e4
LT
208 }
209
210 msq->q_stime = msq->q_rtime = 0;
211 msq->q_ctime = get_seconds();
212 msq->q_cbytes = msq->q_qnum = 0;
1e786937 213 msq->q_qbytes = ns->msg_ctlmnb;
1da177e4
LT
214 msq->q_lspid = msq->q_lrpid = 0;
215 INIT_LIST_HEAD(&msq->q_messages);
216 INIT_LIST_HEAD(&msq->q_receivers);
217 INIT_LIST_HEAD(&msq->q_senders);
7ca7e564 218
dbfcd91f
DB
219 spin_unlock(&msq->q_perm.lock);
220 rcu_read_unlock();
1da177e4 221
7ca7e564 222 return msq->q_perm.id;
1da177e4
LT
223}
224
5a06a363 225static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss)
1da177e4 226{
5a06a363
IM
227 mss->tsk = current;
228 current->state = TASK_INTERRUPTIBLE;
229 list_add_tail(&mss->list, &msq->q_senders);
1da177e4
LT
230}
231
5a06a363 232static inline void ss_del(struct msg_sender *mss)
1da177e4 233{
5a06a363 234 if (mss->list.next != NULL)
1da177e4
LT
235 list_del(&mss->list);
236}
237
5a06a363 238static void ss_wakeup(struct list_head *h, int kill)
1da177e4 239{
41239fe8 240 struct msg_sender *mss, *t;
1da177e4 241
41239fe8 242 list_for_each_entry_safe(mss, t, h, list) {
5a06a363
IM
243 if (kill)
244 mss->list.next = NULL;
1da177e4
LT
245 wake_up_process(mss->tsk);
246 }
247}
248
5a06a363 249static void expunge_all(struct msg_queue *msq, int res)
1da177e4 250{
41239fe8 251 struct msg_receiver *msr, *t;
5a06a363 252
41239fe8 253 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
1da177e4
LT
254 msr->r_msg = NULL;
255 wake_up_process(msr->r_tsk);
256 smp_mb();
257 msr->r_msg = ERR_PTR(res);
258 }
259}
5a06a363
IM
260
261/*
262 * freeque() wakes up waiters on the sender and receiver waiting queue,
f4566f04
ND
263 * removes the message queue from message queue ID IDR, and cleans up all the
264 * messages associated with this queue.
1da177e4 265 *
3e148c79
ND
266 * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held
267 * before freeque() is called. msg_ids.rw_mutex remains locked on exit.
1da177e4 268 */
01b8b07a 269static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
1da177e4 270{
41239fe8 271 struct msg_msg *msg, *t;
01b8b07a 272 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
1da177e4 273
5a06a363
IM
274 expunge_all(msq, -EIDRM);
275 ss_wakeup(&msq->q_senders, 1);
7ca7e564 276 msg_rmid(ns, msq);
1da177e4 277 msg_unlock(msq);
5a06a363 278
41239fe8 279 list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
3ac88a41 280 atomic_dec(&ns->msg_hdrs);
1da177e4
LT
281 free_msg(msg);
282 }
3ac88a41 283 atomic_sub(msq->q_cbytes, &ns->msg_bytes);
1da177e4
LT
284 security_msg_queue_free(msq);
285 ipc_rcu_putref(msq);
286}
287
f4566f04 288/*
3e148c79 289 * Called with msg_ids.rw_mutex and ipcp locked.
f4566f04 290 */
03f02c76 291static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
7748dbfa 292{
03f02c76
ND
293 struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
294
295 return security_msg_queue_associate(msq, msgflg);
7748dbfa
ND
296}
297
e48fbb69 298SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
1da177e4 299{
1e786937 300 struct ipc_namespace *ns;
7748dbfa
ND
301 struct ipc_ops msg_ops;
302 struct ipc_params msg_params;
1e786937
KK
303
304 ns = current->nsproxy->ipc_ns;
7ca7e564 305
7748dbfa
ND
306 msg_ops.getnew = newque;
307 msg_ops.associate = msg_security;
308 msg_ops.more_checks = NULL;
309
310 msg_params.key = key;
311 msg_params.flg = msgflg;
5a06a363 312
7748dbfa 313 return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
1da177e4
LT
314}
315
5a06a363
IM
316static inline unsigned long
317copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
1da177e4
LT
318{
319 switch(version) {
320 case IPC_64:
5a06a363 321 return copy_to_user(buf, in, sizeof(*in));
1da177e4 322 case IPC_OLD:
5a06a363 323 {
1da177e4
LT
324 struct msqid_ds out;
325
5a06a363 326 memset(&out, 0, sizeof(out));
1da177e4
LT
327
328 ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
329
330 out.msg_stime = in->msg_stime;
331 out.msg_rtime = in->msg_rtime;
332 out.msg_ctime = in->msg_ctime;
333
4be929be
AD
334 if (in->msg_cbytes > USHRT_MAX)
335 out.msg_cbytes = USHRT_MAX;
1da177e4
LT
336 else
337 out.msg_cbytes = in->msg_cbytes;
338 out.msg_lcbytes = in->msg_cbytes;
339
4be929be
AD
340 if (in->msg_qnum > USHRT_MAX)
341 out.msg_qnum = USHRT_MAX;
1da177e4
LT
342 else
343 out.msg_qnum = in->msg_qnum;
344
4be929be
AD
345 if (in->msg_qbytes > USHRT_MAX)
346 out.msg_qbytes = USHRT_MAX;
1da177e4
LT
347 else
348 out.msg_qbytes = in->msg_qbytes;
349 out.msg_lqbytes = in->msg_qbytes;
350
351 out.msg_lspid = in->msg_lspid;
352 out.msg_lrpid = in->msg_lrpid;
353
5a06a363
IM
354 return copy_to_user(buf, &out, sizeof(out));
355 }
1da177e4
LT
356 default:
357 return -EINVAL;
358 }
359}
360
5a06a363 361static inline unsigned long
016d7132 362copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
1da177e4
LT
363{
364 switch(version) {
365 case IPC_64:
016d7132 366 if (copy_from_user(out, buf, sizeof(*out)))
1da177e4 367 return -EFAULT;
1da177e4 368 return 0;
1da177e4 369 case IPC_OLD:
5a06a363 370 {
1da177e4
LT
371 struct msqid_ds tbuf_old;
372
5a06a363 373 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
1da177e4
LT
374 return -EFAULT;
375
016d7132
PP
376 out->msg_perm.uid = tbuf_old.msg_perm.uid;
377 out->msg_perm.gid = tbuf_old.msg_perm.gid;
378 out->msg_perm.mode = tbuf_old.msg_perm.mode;
1da177e4 379
5a06a363 380 if (tbuf_old.msg_qbytes == 0)
016d7132 381 out->msg_qbytes = tbuf_old.msg_lqbytes;
1da177e4 382 else
016d7132 383 out->msg_qbytes = tbuf_old.msg_qbytes;
1da177e4
LT
384
385 return 0;
5a06a363 386 }
1da177e4
LT
387 default:
388 return -EINVAL;
389 }
390}
391
a0d092fc
PP
392/*
393 * This function handles some msgctl commands which require the rw_mutex
394 * to be held in write mode.
395 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
396 */
397static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
398 struct msqid_ds __user *buf, int version)
1da177e4 399{
1da177e4 400 struct kern_ipc_perm *ipcp;
f1970c48 401 struct msqid64_ds uninitialized_var(msqid64);
a0d092fc
PP
402 struct msg_queue *msq;
403 int err;
404
405 if (cmd == IPC_SET) {
016d7132 406 if (copy_msqid_from_user(&msqid64, buf, version))
a0d092fc
PP
407 return -EFAULT;
408 }
409
b0e77598 410 ipcp = ipcctl_pre_down(ns, &msg_ids(ns), msqid, cmd,
a5f75e7f
PP
411 &msqid64.msg_perm, msqid64.msg_qbytes);
412 if (IS_ERR(ipcp))
413 return PTR_ERR(ipcp);
a0d092fc 414
a5f75e7f 415 msq = container_of(ipcp, struct msg_queue, q_perm);
a0d092fc
PP
416
417 err = security_msg_queue_msgctl(msq, cmd);
418 if (err)
419 goto out_unlock;
420
421 switch (cmd) {
422 case IPC_RMID:
423 freeque(ns, ipcp);
424 goto out_up;
425 case IPC_SET:
016d7132 426 if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
a0d092fc
PP
427 !capable(CAP_SYS_RESOURCE)) {
428 err = -EPERM;
429 goto out_unlock;
430 }
431
1efdb69b
EB
432 err = ipc_update_perm(&msqid64.msg_perm, ipcp);
433 if (err)
434 goto out_unlock;
435
016d7132 436 msq->q_qbytes = msqid64.msg_qbytes;
a0d092fc 437
a0d092fc
PP
438 msq->q_ctime = get_seconds();
439 /* sleeping receivers might be excluded by
440 * stricter permissions.
441 */
442 expunge_all(msq, -EAGAIN);
443 /* sleeping senders might be able to send
444 * due to a larger queue size.
445 */
446 ss_wakeup(&msq->q_senders, 0);
447 break;
448 default:
449 err = -EINVAL;
450 }
451out_unlock:
452 msg_unlock(msq);
453out_up:
454 up_write(&msg_ids(ns).rw_mutex);
455 return err;
456}
457
e48fbb69 458SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
a0d092fc 459{
5a06a363
IM
460 struct msg_queue *msq;
461 int err, version;
1e786937 462 struct ipc_namespace *ns;
5a06a363 463
1da177e4
LT
464 if (msqid < 0 || cmd < 0)
465 return -EINVAL;
466
467 version = ipc_parse_version(&cmd);
1e786937 468 ns = current->nsproxy->ipc_ns;
1da177e4
LT
469
470 switch (cmd) {
5a06a363
IM
471 case IPC_INFO:
472 case MSG_INFO:
473 {
1da177e4
LT
474 struct msginfo msginfo;
475 int max_id;
5a06a363 476
1da177e4
LT
477 if (!buf)
478 return -EFAULT;
5a06a363
IM
479 /*
480 * We must not return kernel stack data.
1da177e4
LT
481 * due to padding, it's not enough
482 * to set all member fields.
483 */
1da177e4
LT
484 err = security_msg_queue_msgctl(NULL, cmd);
485 if (err)
486 return err;
487
5a06a363 488 memset(&msginfo, 0, sizeof(msginfo));
1e786937
KK
489 msginfo.msgmni = ns->msg_ctlmni;
490 msginfo.msgmax = ns->msg_ctlmax;
491 msginfo.msgmnb = ns->msg_ctlmnb;
1da177e4
LT
492 msginfo.msgssz = MSGSSZ;
493 msginfo.msgseg = MSGSEG;
3e148c79 494 down_read(&msg_ids(ns).rw_mutex);
1da177e4 495 if (cmd == MSG_INFO) {
1e786937 496 msginfo.msgpool = msg_ids(ns).in_use;
3ac88a41
KK
497 msginfo.msgmap = atomic_read(&ns->msg_hdrs);
498 msginfo.msgtql = atomic_read(&ns->msg_bytes);
1da177e4
LT
499 } else {
500 msginfo.msgmap = MSGMAP;
501 msginfo.msgpool = MSGPOOL;
502 msginfo.msgtql = MSGTQL;
503 }
7ca7e564 504 max_id = ipc_get_maxid(&msg_ids(ns));
3e148c79 505 up_read(&msg_ids(ns).rw_mutex);
5a06a363 506 if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
1da177e4 507 return -EFAULT;
5a06a363 508 return (max_id < 0) ? 0 : max_id;
1da177e4 509 }
7ca7e564 510 case MSG_STAT: /* msqid is an index rather than a msg queue id */
1da177e4
LT
511 case IPC_STAT:
512 {
513 struct msqid64_ds tbuf;
514 int success_return;
5a06a363 515
1da177e4
LT
516 if (!buf)
517 return -EFAULT;
1da177e4 518
5a06a363 519 if (cmd == MSG_STAT) {
023a5355
ND
520 msq = msg_lock(ns, msqid);
521 if (IS_ERR(msq))
522 return PTR_ERR(msq);
7ca7e564 523 success_return = msq->q_perm.id;
1da177e4 524 } else {
023a5355
ND
525 msq = msg_lock_check(ns, msqid);
526 if (IS_ERR(msq))
527 return PTR_ERR(msq);
1da177e4
LT
528 success_return = 0;
529 }
530 err = -EACCES;
b0e77598 531 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
1da177e4
LT
532 goto out_unlock;
533
534 err = security_msg_queue_msgctl(msq, cmd);
535 if (err)
536 goto out_unlock;
537
023a5355
ND
538 memset(&tbuf, 0, sizeof(tbuf));
539
1da177e4
LT
540 kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
541 tbuf.msg_stime = msq->q_stime;
542 tbuf.msg_rtime = msq->q_rtime;
543 tbuf.msg_ctime = msq->q_ctime;
544 tbuf.msg_cbytes = msq->q_cbytes;
545 tbuf.msg_qnum = msq->q_qnum;
546 tbuf.msg_qbytes = msq->q_qbytes;
547 tbuf.msg_lspid = msq->q_lspid;
548 tbuf.msg_lrpid = msq->q_lrpid;
549 msg_unlock(msq);
550 if (copy_msqid_to_user(buf, &tbuf, version))
551 return -EFAULT;
552 return success_return;
553 }
554 case IPC_SET:
1da177e4 555 case IPC_RMID:
a0d092fc
PP
556 err = msgctl_down(ns, msqid, cmd, buf, version);
557 return err;
1da177e4
LT
558 default:
559 return -EINVAL;
560 }
561
1da177e4
LT
562out_unlock:
563 msg_unlock(msq);
564 return err;
565}
566
5a06a363 567static int testmsg(struct msg_msg *msg, long type, int mode)
1da177e4
LT
568{
569 switch(mode)
570 {
571 case SEARCH_ANY:
8ac6ed58 572 case SEARCH_NUMBER:
1da177e4
LT
573 return 1;
574 case SEARCH_LESSEQUAL:
5a06a363 575 if (msg->m_type <=type)
1da177e4
LT
576 return 1;
577 break;
578 case SEARCH_EQUAL:
5a06a363 579 if (msg->m_type == type)
1da177e4
LT
580 return 1;
581 break;
582 case SEARCH_NOTEQUAL:
5a06a363 583 if (msg->m_type != type)
1da177e4
LT
584 return 1;
585 break;
586 }
587 return 0;
588}
589
5a06a363 590static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg)
1da177e4 591{
41239fe8 592 struct msg_receiver *msr, *t;
5a06a363 593
41239fe8 594 list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
5a06a363
IM
595 if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
596 !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
597 msr->r_msgtype, msr->r_mode)) {
598
1da177e4 599 list_del(&msr->r_list);
5a06a363 600 if (msr->r_maxsize < msg->m_ts) {
1da177e4
LT
601 msr->r_msg = NULL;
602 wake_up_process(msr->r_tsk);
603 smp_mb();
604 msr->r_msg = ERR_PTR(-E2BIG);
605 } else {
606 msr->r_msg = NULL;
b488893a 607 msq->q_lrpid = task_pid_vnr(msr->r_tsk);
1da177e4
LT
608 msq->q_rtime = get_seconds();
609 wake_up_process(msr->r_tsk);
610 smp_mb();
611 msr->r_msg = msg;
5a06a363 612
1da177e4
LT
613 return 1;
614 }
615 }
616 }
617 return 0;
618}
619
651971cb 620long do_msgsnd(int msqid, long mtype, void __user *mtext,
621 size_t msgsz, int msgflg)
1da177e4
LT
622{
623 struct msg_queue *msq;
624 struct msg_msg *msg;
1da177e4 625 int err;
1e786937
KK
626 struct ipc_namespace *ns;
627
628 ns = current->nsproxy->ipc_ns;
5a06a363 629
1e786937 630 if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
1da177e4 631 return -EINVAL;
1da177e4
LT
632 if (mtype < 1)
633 return -EINVAL;
634
651971cb 635 msg = load_msg(mtext, msgsz);
5a06a363 636 if (IS_ERR(msg))
1da177e4
LT
637 return PTR_ERR(msg);
638
639 msg->m_type = mtype;
640 msg->m_ts = msgsz;
641
023a5355
ND
642 msq = msg_lock_check(ns, msqid);
643 if (IS_ERR(msq)) {
644 err = PTR_ERR(msq);
1da177e4 645 goto out_free;
023a5355 646 }
1da177e4
LT
647
648 for (;;) {
649 struct msg_sender s;
650
5a06a363 651 err = -EACCES;
b0e77598 652 if (ipcperms(ns, &msq->q_perm, S_IWUGO))
1da177e4
LT
653 goto out_unlock_free;
654
655 err = security_msg_queue_msgsnd(msq, msg, msgflg);
656 if (err)
657 goto out_unlock_free;
658
5a06a363 659 if (msgsz + msq->q_cbytes <= msq->q_qbytes &&
1da177e4
LT
660 1 + msq->q_qnum <= msq->q_qbytes) {
661 break;
662 }
663
664 /* queue full, wait: */
5a06a363
IM
665 if (msgflg & IPC_NOWAIT) {
666 err = -EAGAIN;
1da177e4
LT
667 goto out_unlock_free;
668 }
669 ss_add(msq, &s);
6062a8dc
RR
670
671 if (!ipc_rcu_getref(msq)) {
672 err = -EIDRM;
673 goto out_unlock_free;
674 }
675
1da177e4
LT
676 msg_unlock(msq);
677 schedule();
678
679 ipc_lock_by_ptr(&msq->q_perm);
680 ipc_rcu_putref(msq);
681 if (msq->q_perm.deleted) {
682 err = -EIDRM;
683 goto out_unlock_free;
684 }
685 ss_del(&s);
5a06a363 686
1da177e4 687 if (signal_pending(current)) {
5a06a363 688 err = -ERESTARTNOHAND;
1da177e4
LT
689 goto out_unlock_free;
690 }
691 }
692
b488893a 693 msq->q_lspid = task_tgid_vnr(current);
1da177e4
LT
694 msq->q_stime = get_seconds();
695
5a06a363 696 if (!pipelined_send(msq, msg)) {
25985edc 697 /* no one is waiting for this message, enqueue it */
5a06a363 698 list_add_tail(&msg->m_list, &msq->q_messages);
1da177e4
LT
699 msq->q_cbytes += msgsz;
700 msq->q_qnum++;
3ac88a41
KK
701 atomic_add(msgsz, &ns->msg_bytes);
702 atomic_inc(&ns->msg_hdrs);
1da177e4 703 }
5a06a363 704
1da177e4
LT
705 err = 0;
706 msg = NULL;
707
708out_unlock_free:
709 msg_unlock(msq);
710out_free:
5a06a363 711 if (msg != NULL)
1da177e4
LT
712 free_msg(msg);
713 return err;
714}
715
e48fbb69
HC
716SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
717 int, msgflg)
651971cb 718{
719 long mtype;
720
721 if (get_user(mtype, &msgp->mtype))
722 return -EFAULT;
723 return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
724}
725
5a06a363 726static inline int convert_mode(long *msgtyp, int msgflg)
1da177e4 727{
8ac6ed58
PH
728 if (msgflg & MSG_COPY)
729 return SEARCH_NUMBER;
5a06a363 730 /*
1da177e4
LT
731 * find message of correct type.
732 * msgtyp = 0 => get first.
733 * msgtyp > 0 => get first message of matching type.
5a06a363 734 * msgtyp < 0 => get message with least type must be < abs(msgtype).
1da177e4 735 */
5a06a363 736 if (*msgtyp == 0)
1da177e4 737 return SEARCH_ANY;
5a06a363
IM
738 if (*msgtyp < 0) {
739 *msgtyp = -*msgtyp;
1da177e4
LT
740 return SEARCH_LESSEQUAL;
741 }
5a06a363 742 if (msgflg & MSG_EXCEPT)
1da177e4
LT
743 return SEARCH_NOTEQUAL;
744 return SEARCH_EQUAL;
745}
746
f9dd87f4
SK
747static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
748{
749 struct msgbuf __user *msgp = dest;
750 size_t msgsz;
751
752 if (put_user(msg->m_type, &msgp->mtype))
753 return -EFAULT;
754
755 msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
756 if (store_msg(msgp->mtext, msg, msgsz))
757 return -EFAULT;
758 return msgsz;
759}
760
4a674f34 761#ifdef CONFIG_CHECKPOINT_RESTORE
3fcfe786
SK
762/*
763 * This function creates new kernel message structure, large enough to store
764 * bufsz message bytes.
765 */
8ac6ed58 766static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
4a674f34
SK
767{
768 struct msg_msg *copy;
769
4a674f34
SK
770 /*
771 * Create dummy message to copy real message to.
772 */
773 copy = load_msg(buf, bufsz);
774 if (!IS_ERR(copy))
775 copy->m_ts = bufsz;
776 return copy;
777}
778
85398aa8 779static inline void free_copy(struct msg_msg *copy)
4a674f34 780{
85398aa8 781 if (copy)
4a674f34
SK
782 free_msg(copy);
783}
784#else
8ac6ed58 785static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
b30efe27
SK
786{
787 return ERR_PTR(-ENOSYS);
788}
789
85398aa8
SK
790static inline void free_copy(struct msg_msg *copy)
791{
792}
4a674f34
SK
793#endif
794
daaf74cf
PH
795static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
796{
797 struct msg_msg *msg;
798 long count = 0;
799
800 list_for_each_entry(msg, &msq->q_messages, m_list) {
801 if (testmsg(msg, *msgtyp, mode) &&
802 !security_msg_queue_msgrcv(msq, msg, current,
803 *msgtyp, mode)) {
804 if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
805 *msgtyp = msg->m_type - 1;
806 } else if (mode == SEARCH_NUMBER) {
807 if (*msgtyp == count)
808 return msg;
809 } else
810 return msg;
811 count++;
812 }
813 }
814
815 return ERR_PTR(-EAGAIN);
816}
817
818
f9dd87f4
SK
819long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp,
820 int msgflg,
821 long (*msg_handler)(void __user *, struct msg_msg *, size_t))
1da177e4
LT
822{
823 struct msg_queue *msq;
824 struct msg_msg *msg;
825 int mode;
1e786937 826 struct ipc_namespace *ns;
85398aa8 827 struct msg_msg *copy = NULL;
1da177e4 828
88b9e456
PH
829 ns = current->nsproxy->ipc_ns;
830
f9dd87f4 831 if (msqid < 0 || (long) bufsz < 0)
1da177e4 832 return -EINVAL;
4a674f34 833 if (msgflg & MSG_COPY) {
8ac6ed58 834 copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax));
4a674f34
SK
835 if (IS_ERR(copy))
836 return PTR_ERR(copy);
837 }
5a06a363 838 mode = convert_mode(&msgtyp, msgflg);
1da177e4 839
023a5355 840 msq = msg_lock_check(ns, msqid);
4a674f34 841 if (IS_ERR(msq)) {
85398aa8 842 free_copy(copy);
023a5355 843 return PTR_ERR(msq);
4a674f34 844 }
1da177e4
LT
845
846 for (;;) {
847 struct msg_receiver msr_d;
1da177e4
LT
848
849 msg = ERR_PTR(-EACCES);
b0e77598 850 if (ipcperms(ns, &msq->q_perm, S_IRUGO))
1da177e4
LT
851 goto out_unlock;
852
daaf74cf
PH
853 msg = find_msg(msq, &msgtyp, mode);
854
5a06a363
IM
855 if (!IS_ERR(msg)) {
856 /*
857 * Found a suitable message.
858 * Unlink it from the queue.
859 */
f9dd87f4 860 if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
1da177e4
LT
861 msg = ERR_PTR(-E2BIG);
862 goto out_unlock;
863 }
3fcfe786
SK
864 /*
865 * If we are copying, then do not unlink message and do
866 * not update queue parameters.
867 */
852028af
PH
868 if (msgflg & MSG_COPY) {
869 msg = copy_msg(msg, copy);
4a674f34 870 goto out_unlock;
852028af 871 }
1da177e4
LT
872 list_del(&msg->m_list);
873 msq->q_qnum--;
874 msq->q_rtime = get_seconds();
b488893a 875 msq->q_lrpid = task_tgid_vnr(current);
1da177e4 876 msq->q_cbytes -= msg->m_ts;
3ac88a41
KK
877 atomic_sub(msg->m_ts, &ns->msg_bytes);
878 atomic_dec(&ns->msg_hdrs);
5a06a363 879 ss_wakeup(&msq->q_senders, 0);
1da177e4
LT
880 msg_unlock(msq);
881 break;
882 }
883 /* No message waiting. Wait for a message */
884 if (msgflg & IPC_NOWAIT) {
885 msg = ERR_PTR(-ENOMSG);
886 goto out_unlock;
887 }
5a06a363 888 list_add_tail(&msr_d.r_list, &msq->q_receivers);
1da177e4
LT
889 msr_d.r_tsk = current;
890 msr_d.r_msgtype = msgtyp;
891 msr_d.r_mode = mode;
5a06a363 892 if (msgflg & MSG_NOERROR)
1da177e4 893 msr_d.r_maxsize = INT_MAX;
5a06a363 894 else
f9dd87f4 895 msr_d.r_maxsize = bufsz;
1da177e4
LT
896 msr_d.r_msg = ERR_PTR(-EAGAIN);
897 current->state = TASK_INTERRUPTIBLE;
898 msg_unlock(msq);
899
900 schedule();
901
902 /* Lockless receive, part 1:
903 * Disable preemption. We don't hold a reference to the queue
904 * and getting a reference would defeat the idea of a lockless
905 * operation, thus the code relies on rcu to guarantee the
25985edc 906 * existence of msq:
1da177e4
LT
907 * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
908 * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
909 * rcu_read_lock() prevents preemption between reading r_msg
910 * and the spin_lock() inside ipc_lock_by_ptr().
911 */
912 rcu_read_lock();
913
914 /* Lockless receive, part 2:
915 * Wait until pipelined_send or expunge_all are outside of
916 * wake_up_process(). There is a race with exit(), see
917 * ipc/mqueue.c for the details.
918 */
5a06a363 919 msg = (struct msg_msg*)msr_d.r_msg;
1da177e4
LT
920 while (msg == NULL) {
921 cpu_relax();
5a06a363 922 msg = (struct msg_msg *)msr_d.r_msg;
1da177e4
LT
923 }
924
925 /* Lockless receive, part 3:
926 * If there is a message or an error then accept it without
927 * locking.
928 */
5a06a363 929 if (msg != ERR_PTR(-EAGAIN)) {
1da177e4
LT
930 rcu_read_unlock();
931 break;
932 }
933
934 /* Lockless receive, part 3:
935 * Acquire the queue spinlock.
936 */
937 ipc_lock_by_ptr(&msq->q_perm);
938 rcu_read_unlock();
939
940 /* Lockless receive, part 4:
941 * Repeat test after acquiring the spinlock.
942 */
943 msg = (struct msg_msg*)msr_d.r_msg;
5a06a363 944 if (msg != ERR_PTR(-EAGAIN))
1da177e4
LT
945 goto out_unlock;
946
947 list_del(&msr_d.r_list);
948 if (signal_pending(current)) {
949 msg = ERR_PTR(-ERESTARTNOHAND);
950out_unlock:
951 msg_unlock(msq);
952 break;
953 }
954 }
4a674f34 955 if (IS_ERR(msg)) {
85398aa8 956 free_copy(copy);
5a06a363 957 return PTR_ERR(msg);
4a674f34 958 }
1da177e4 959
f9dd87f4 960 bufsz = msg_handler(buf, msg, bufsz);
1da177e4 961 free_msg(msg);
5a06a363 962
f9dd87f4 963 return bufsz;
1da177e4
LT
964}
965
e48fbb69
HC
966SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
967 long, msgtyp, int, msgflg)
651971cb 968{
f9dd87f4 969 return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
651971cb 970}
971
1da177e4 972#ifdef CONFIG_PROC_FS
19b4946c 973static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
1da177e4 974{
1efdb69b 975 struct user_namespace *user_ns = seq_user_ns(s);
19b4946c
MW
976 struct msg_queue *msq = it;
977
978 return seq_printf(s,
5a06a363
IM
979 "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
980 msq->q_perm.key,
7ca7e564 981 msq->q_perm.id,
5a06a363
IM
982 msq->q_perm.mode,
983 msq->q_cbytes,
984 msq->q_qnum,
985 msq->q_lspid,
986 msq->q_lrpid,
1efdb69b
EB
987 from_kuid_munged(user_ns, msq->q_perm.uid),
988 from_kgid_munged(user_ns, msq->q_perm.gid),
989 from_kuid_munged(user_ns, msq->q_perm.cuid),
990 from_kgid_munged(user_ns, msq->q_perm.cgid),
5a06a363
IM
991 msq->q_stime,
992 msq->q_rtime,
993 msq->q_ctime);
1da177e4
LT
994}
995#endif