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Commit | Line | Data |
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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> | |
84f001e1 | 33 | #include <linux/sched/wake_q.h> |
1da177e4 LT |
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 | 41 | #include <asm/current.h> |
7153e402 | 42 | #include <linux/uaccess.h> |
1da177e4 LT |
43 | #include "util.h" |
44 | ||
4bb6657d | 45 | /* one msg_receiver structure for each sleeping receiver */ |
1da177e4 | 46 | struct msg_receiver { |
5a06a363 IM |
47 | struct list_head r_list; |
48 | struct task_struct *r_tsk; | |
1da177e4 | 49 | |
5a06a363 IM |
50 | int r_mode; |
51 | long r_msgtype; | |
52 | long r_maxsize; | |
1da177e4 | 53 | |
ee51636c | 54 | struct msg_msg *r_msg; |
1da177e4 LT |
55 | }; |
56 | ||
57 | /* one msg_sender for each sleeping sender */ | |
58 | struct msg_sender { | |
5a06a363 IM |
59 | struct list_head list; |
60 | struct task_struct *tsk; | |
ed27f912 | 61 | size_t msgsz; |
1da177e4 LT |
62 | }; |
63 | ||
64 | #define SEARCH_ANY 1 | |
65 | #define SEARCH_EQUAL 2 | |
66 | #define SEARCH_NOTEQUAL 3 | |
67 | #define SEARCH_LESSEQUAL 4 | |
8ac6ed58 | 68 | #define SEARCH_NUMBER 5 |
1da177e4 | 69 | |
ed2ddbf8 | 70 | #define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS]) |
1da177e4 | 71 | |
a5001a0d DB |
72 | static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id) |
73 | { | |
55b7ae50 | 74 | struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&msg_ids(ns), id); |
a5001a0d DB |
75 | |
76 | if (IS_ERR(ipcp)) | |
77 | return ERR_CAST(ipcp); | |
78 | ||
79 | return container_of(ipcp, struct msg_queue, q_perm); | |
80 | } | |
81 | ||
82 | static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns, | |
83 | int id) | |
84 | { | |
85 | struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id); | |
86 | ||
87 | if (IS_ERR(ipcp)) | |
88 | return ERR_CAST(ipcp); | |
89 | ||
90 | return container_of(ipcp, struct msg_queue, q_perm); | |
91 | } | |
92 | ||
7ca7e564 ND |
93 | static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s) |
94 | { | |
95 | ipc_rmid(&msg_ids(ns), &s->q_perm); | |
96 | } | |
97 | ||
9ef5932f KC |
98 | static void __msg_free(struct msg_queue *msq) |
99 | { | |
100 | kvfree(msq); | |
101 | } | |
102 | ||
53dad6d3 DB |
103 | static void msg_rcu_free(struct rcu_head *head) |
104 | { | |
dba4cdd3 MS |
105 | struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu); |
106 | struct msg_queue *msq = container_of(p, struct msg_queue, q_perm); | |
53dad6d3 DB |
107 | |
108 | security_msg_queue_free(msq); | |
9ef5932f | 109 | __msg_free(msq); |
53dad6d3 DB |
110 | } |
111 | ||
52f90890 KC |
112 | static struct msg_queue *msg_alloc(void) |
113 | { | |
114 | struct msg_queue *msq; | |
115 | ||
116 | msq = kvmalloc(sizeof(*msq), GFP_KERNEL); | |
117 | if (unlikely(!msq)) | |
118 | return NULL; | |
119 | ||
120 | atomic_set(&msq->q_perm.refcount, 1); | |
121 | ||
122 | return msq; | |
123 | } | |
124 | ||
f4566f04 ND |
125 | /** |
126 | * newque - Create a new msg queue | |
127 | * @ns: namespace | |
128 | * @params: ptr to the structure that contains the key and msgflg | |
129 | * | |
d9a605e4 | 130 | * Called with msg_ids.rwsem held (writer) |
f4566f04 | 131 | */ |
7748dbfa | 132 | static int newque(struct ipc_namespace *ns, struct ipc_params *params) |
1da177e4 | 133 | { |
1da177e4 | 134 | struct msg_queue *msq; |
5a06a363 | 135 | int id, retval; |
7748dbfa ND |
136 | key_t key = params->key; |
137 | int msgflg = params->flg; | |
1da177e4 | 138 | |
52f90890 | 139 | msq = msg_alloc(); |
5a06a363 | 140 | if (!msq) |
1da177e4 LT |
141 | return -ENOMEM; |
142 | ||
5a06a363 | 143 | msq->q_perm.mode = msgflg & S_IRWXUGO; |
1da177e4 LT |
144 | msq->q_perm.key = key; |
145 | ||
146 | msq->q_perm.security = NULL; | |
147 | retval = security_msg_queue_alloc(msq); | |
148 | if (retval) { | |
9ef5932f | 149 | __msg_free(msq); |
1da177e4 LT |
150 | return retval; |
151 | } | |
152 | ||
1da177e4 LT |
153 | msq->q_stime = msq->q_rtime = 0; |
154 | msq->q_ctime = get_seconds(); | |
155 | msq->q_cbytes = msq->q_qnum = 0; | |
1e786937 | 156 | msq->q_qbytes = ns->msg_ctlmnb; |
1da177e4 LT |
157 | msq->q_lspid = msq->q_lrpid = 0; |
158 | INIT_LIST_HEAD(&msq->q_messages); | |
159 | INIT_LIST_HEAD(&msq->q_receivers); | |
160 | INIT_LIST_HEAD(&msq->q_senders); | |
7ca7e564 | 161 | |
b9a53227 LT |
162 | /* ipc_addid() locks msq upon success. */ |
163 | id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); | |
164 | if (id < 0) { | |
dba4cdd3 | 165 | ipc_rcu_putref(&msq->q_perm, msg_rcu_free); |
b9a53227 LT |
166 | return id; |
167 | } | |
168 | ||
cf9d5d78 | 169 | ipc_unlock_object(&msq->q_perm); |
dbfcd91f | 170 | rcu_read_unlock(); |
1da177e4 | 171 | |
7ca7e564 | 172 | return msq->q_perm.id; |
1da177e4 LT |
173 | } |
174 | ||
ed27f912 DB |
175 | static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz) |
176 | { | |
177 | return msgsz + msq->q_cbytes <= msq->q_qbytes && | |
178 | 1 + msq->q_qnum <= msq->q_qbytes; | |
179 | } | |
180 | ||
181 | static inline void ss_add(struct msg_queue *msq, | |
182 | struct msg_sender *mss, size_t msgsz) | |
1da177e4 | 183 | { |
5a06a363 | 184 | mss->tsk = current; |
ed27f912 | 185 | mss->msgsz = msgsz; |
f75a2f35 | 186 | __set_current_state(TASK_INTERRUPTIBLE); |
5a06a363 | 187 | list_add_tail(&mss->list, &msq->q_senders); |
1da177e4 LT |
188 | } |
189 | ||
5a06a363 | 190 | static inline void ss_del(struct msg_sender *mss) |
1da177e4 | 191 | { |
ed27f912 | 192 | if (mss->list.next) |
1da177e4 LT |
193 | list_del(&mss->list); |
194 | } | |
195 | ||
ed27f912 | 196 | static void ss_wakeup(struct msg_queue *msq, |
d0d6a2a9 | 197 | struct wake_q_head *wake_q, bool kill) |
1da177e4 | 198 | { |
41239fe8 | 199 | struct msg_sender *mss, *t; |
ed27f912 DB |
200 | struct task_struct *stop_tsk = NULL; |
201 | struct list_head *h = &msq->q_senders; | |
1da177e4 | 202 | |
41239fe8 | 203 | list_for_each_entry_safe(mss, t, h, list) { |
5a06a363 IM |
204 | if (kill) |
205 | mss->list.next = NULL; | |
ed27f912 DB |
206 | |
207 | /* | |
208 | * Stop at the first task we don't wakeup, | |
209 | * we've already iterated the original | |
210 | * sender queue. | |
211 | */ | |
212 | else if (stop_tsk == mss->tsk) | |
213 | break; | |
214 | /* | |
215 | * We are not in an EIDRM scenario here, therefore | |
216 | * verify that we really need to wakeup the task. | |
217 | * To maintain current semantics and wakeup order, | |
218 | * move the sender to the tail on behalf of the | |
219 | * blocked task. | |
220 | */ | |
221 | else if (!msg_fits_inqueue(msq, mss->msgsz)) { | |
222 | if (!stop_tsk) | |
223 | stop_tsk = mss->tsk; | |
224 | ||
225 | list_move_tail(&mss->list, &msq->q_senders); | |
226 | continue; | |
227 | } | |
228 | ||
e3658538 | 229 | wake_q_add(wake_q, mss->tsk); |
1da177e4 LT |
230 | } |
231 | } | |
232 | ||
ee51636c SAS |
233 | static void expunge_all(struct msg_queue *msq, int res, |
234 | struct wake_q_head *wake_q) | |
1da177e4 | 235 | { |
41239fe8 | 236 | struct msg_receiver *msr, *t; |
5a06a363 | 237 | |
41239fe8 | 238 | list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { |
ee51636c SAS |
239 | wake_q_add(wake_q, msr->r_tsk); |
240 | WRITE_ONCE(msr->r_msg, ERR_PTR(res)); | |
1da177e4 LT |
241 | } |
242 | } | |
5a06a363 IM |
243 | |
244 | /* | |
245 | * freeque() wakes up waiters on the sender and receiver waiting queue, | |
f4566f04 ND |
246 | * removes the message queue from message queue ID IDR, and cleans up all the |
247 | * messages associated with this queue. | |
1da177e4 | 248 | * |
d9a605e4 DB |
249 | * msg_ids.rwsem (writer) and the spinlock for this message queue are held |
250 | * before freeque() is called. msg_ids.rwsem remains locked on exit. | |
1da177e4 | 251 | */ |
01b8b07a | 252 | static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) |
1da177e4 | 253 | { |
41239fe8 | 254 | struct msg_msg *msg, *t; |
01b8b07a | 255 | struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); |
194a6b5b | 256 | DEFINE_WAKE_Q(wake_q); |
1da177e4 | 257 | |
ee51636c | 258 | expunge_all(msq, -EIDRM, &wake_q); |
ed27f912 | 259 | ss_wakeup(msq, &wake_q, true); |
7ca7e564 | 260 | msg_rmid(ns, msq); |
4718787d | 261 | ipc_unlock_object(&msq->q_perm); |
ee51636c | 262 | wake_up_q(&wake_q); |
4718787d | 263 | rcu_read_unlock(); |
5a06a363 | 264 | |
41239fe8 | 265 | list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) { |
3ac88a41 | 266 | atomic_dec(&ns->msg_hdrs); |
1da177e4 LT |
267 | free_msg(msg); |
268 | } | |
3ac88a41 | 269 | atomic_sub(msq->q_cbytes, &ns->msg_bytes); |
dba4cdd3 | 270 | ipc_rcu_putref(&msq->q_perm, msg_rcu_free); |
1da177e4 LT |
271 | } |
272 | ||
f4566f04 | 273 | /* |
d9a605e4 | 274 | * Called with msg_ids.rwsem and ipcp locked. |
f4566f04 | 275 | */ |
03f02c76 | 276 | static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg) |
7748dbfa | 277 | { |
03f02c76 ND |
278 | struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); |
279 | ||
280 | return security_msg_queue_associate(msq, msgflg); | |
7748dbfa ND |
281 | } |
282 | ||
e48fbb69 | 283 | SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg) |
1da177e4 | 284 | { |
1e786937 | 285 | struct ipc_namespace *ns; |
eb66ec44 MK |
286 | static const struct ipc_ops msg_ops = { |
287 | .getnew = newque, | |
288 | .associate = msg_security, | |
289 | }; | |
7748dbfa | 290 | struct ipc_params msg_params; |
1e786937 KK |
291 | |
292 | ns = current->nsproxy->ipc_ns; | |
7ca7e564 | 293 | |
7748dbfa ND |
294 | msg_params.key = key; |
295 | msg_params.flg = msgflg; | |
5a06a363 | 296 | |
7748dbfa | 297 | return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params); |
1da177e4 LT |
298 | } |
299 | ||
5a06a363 IM |
300 | static inline unsigned long |
301 | copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) | |
1da177e4 | 302 | { |
239521f3 | 303 | switch (version) { |
1da177e4 | 304 | case IPC_64: |
5a06a363 | 305 | return copy_to_user(buf, in, sizeof(*in)); |
1da177e4 | 306 | case IPC_OLD: |
5a06a363 | 307 | { |
1da177e4 LT |
308 | struct msqid_ds out; |
309 | ||
5a06a363 | 310 | memset(&out, 0, sizeof(out)); |
1da177e4 LT |
311 | |
312 | ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); | |
313 | ||
314 | out.msg_stime = in->msg_stime; | |
315 | out.msg_rtime = in->msg_rtime; | |
316 | out.msg_ctime = in->msg_ctime; | |
317 | ||
4be929be AD |
318 | if (in->msg_cbytes > USHRT_MAX) |
319 | out.msg_cbytes = USHRT_MAX; | |
1da177e4 LT |
320 | else |
321 | out.msg_cbytes = in->msg_cbytes; | |
322 | out.msg_lcbytes = in->msg_cbytes; | |
323 | ||
4be929be AD |
324 | if (in->msg_qnum > USHRT_MAX) |
325 | out.msg_qnum = USHRT_MAX; | |
1da177e4 LT |
326 | else |
327 | out.msg_qnum = in->msg_qnum; | |
328 | ||
4be929be AD |
329 | if (in->msg_qbytes > USHRT_MAX) |
330 | out.msg_qbytes = USHRT_MAX; | |
1da177e4 LT |
331 | else |
332 | out.msg_qbytes = in->msg_qbytes; | |
333 | out.msg_lqbytes = in->msg_qbytes; | |
334 | ||
335 | out.msg_lspid = in->msg_lspid; | |
336 | out.msg_lrpid = in->msg_lrpid; | |
337 | ||
5a06a363 IM |
338 | return copy_to_user(buf, &out, sizeof(out)); |
339 | } | |
1da177e4 LT |
340 | default: |
341 | return -EINVAL; | |
342 | } | |
343 | } | |
344 | ||
5a06a363 | 345 | static inline unsigned long |
016d7132 | 346 | copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version) |
1da177e4 | 347 | { |
239521f3 | 348 | switch (version) { |
1da177e4 | 349 | case IPC_64: |
016d7132 | 350 | if (copy_from_user(out, buf, sizeof(*out))) |
1da177e4 | 351 | return -EFAULT; |
1da177e4 | 352 | return 0; |
1da177e4 | 353 | case IPC_OLD: |
5a06a363 | 354 | { |
1da177e4 LT |
355 | struct msqid_ds tbuf_old; |
356 | ||
5a06a363 | 357 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) |
1da177e4 LT |
358 | return -EFAULT; |
359 | ||
239521f3 MS |
360 | out->msg_perm.uid = tbuf_old.msg_perm.uid; |
361 | out->msg_perm.gid = tbuf_old.msg_perm.gid; | |
362 | out->msg_perm.mode = tbuf_old.msg_perm.mode; | |
1da177e4 | 363 | |
5a06a363 | 364 | if (tbuf_old.msg_qbytes == 0) |
016d7132 | 365 | out->msg_qbytes = tbuf_old.msg_lqbytes; |
1da177e4 | 366 | else |
016d7132 | 367 | out->msg_qbytes = tbuf_old.msg_qbytes; |
1da177e4 LT |
368 | |
369 | return 0; | |
5a06a363 | 370 | } |
1da177e4 LT |
371 | default: |
372 | return -EINVAL; | |
373 | } | |
374 | } | |
375 | ||
a0d092fc | 376 | /* |
d9a605e4 | 377 | * This function handles some msgctl commands which require the rwsem |
a0d092fc | 378 | * to be held in write mode. |
d9a605e4 | 379 | * NOTE: no locks must be held, the rwsem is taken inside this function. |
a0d092fc PP |
380 | */ |
381 | static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, | |
382 | struct msqid_ds __user *buf, int version) | |
1da177e4 | 383 | { |
1da177e4 | 384 | struct kern_ipc_perm *ipcp; |
f1970c48 | 385 | struct msqid64_ds uninitialized_var(msqid64); |
a0d092fc PP |
386 | struct msg_queue *msq; |
387 | int err; | |
388 | ||
389 | if (cmd == IPC_SET) { | |
016d7132 | 390 | if (copy_msqid_from_user(&msqid64, buf, version)) |
a0d092fc PP |
391 | return -EFAULT; |
392 | } | |
393 | ||
d9a605e4 | 394 | down_write(&msg_ids(ns).rwsem); |
7b4cc5d8 DB |
395 | rcu_read_lock(); |
396 | ||
15724ecb DB |
397 | ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd, |
398 | &msqid64.msg_perm, msqid64.msg_qbytes); | |
7b4cc5d8 DB |
399 | if (IS_ERR(ipcp)) { |
400 | err = PTR_ERR(ipcp); | |
7b4cc5d8 DB |
401 | goto out_unlock1; |
402 | } | |
a0d092fc | 403 | |
a5f75e7f | 404 | msq = container_of(ipcp, struct msg_queue, q_perm); |
a0d092fc PP |
405 | |
406 | err = security_msg_queue_msgctl(msq, cmd); | |
407 | if (err) | |
15724ecb | 408 | goto out_unlock1; |
a0d092fc PP |
409 | |
410 | switch (cmd) { | |
411 | case IPC_RMID: | |
15724ecb | 412 | ipc_lock_object(&msq->q_perm); |
7b4cc5d8 | 413 | /* freeque unlocks the ipc object and rcu */ |
a0d092fc PP |
414 | freeque(ns, ipcp); |
415 | goto out_up; | |
416 | case IPC_SET: | |
e3658538 | 417 | { |
194a6b5b | 418 | DEFINE_WAKE_Q(wake_q); |
e3658538 | 419 | |
016d7132 | 420 | if (msqid64.msg_qbytes > ns->msg_ctlmnb && |
a0d092fc PP |
421 | !capable(CAP_SYS_RESOURCE)) { |
422 | err = -EPERM; | |
15724ecb | 423 | goto out_unlock1; |
a0d092fc PP |
424 | } |
425 | ||
15724ecb | 426 | ipc_lock_object(&msq->q_perm); |
1efdb69b EB |
427 | err = ipc_update_perm(&msqid64.msg_perm, ipcp); |
428 | if (err) | |
7b4cc5d8 | 429 | goto out_unlock0; |
1efdb69b | 430 | |
016d7132 | 431 | msq->q_qbytes = msqid64.msg_qbytes; |
a0d092fc | 432 | |
a0d092fc | 433 | msq->q_ctime = get_seconds(); |
e3658538 DB |
434 | /* |
435 | * Sleeping receivers might be excluded by | |
a0d092fc PP |
436 | * stricter permissions. |
437 | */ | |
ee51636c | 438 | expunge_all(msq, -EAGAIN, &wake_q); |
e3658538 DB |
439 | /* |
440 | * Sleeping senders might be able to send | |
a0d092fc PP |
441 | * due to a larger queue size. |
442 | */ | |
ed27f912 | 443 | ss_wakeup(msq, &wake_q, false); |
e3658538 DB |
444 | ipc_unlock_object(&msq->q_perm); |
445 | wake_up_q(&wake_q); | |
446 | ||
447 | goto out_unlock1; | |
448 | } | |
a0d092fc PP |
449 | default: |
450 | err = -EINVAL; | |
15724ecb | 451 | goto out_unlock1; |
a0d092fc | 452 | } |
7b4cc5d8 DB |
453 | |
454 | out_unlock0: | |
455 | ipc_unlock_object(&msq->q_perm); | |
456 | out_unlock1: | |
457 | rcu_read_unlock(); | |
a0d092fc | 458 | out_up: |
d9a605e4 | 459 | up_write(&msg_ids(ns).rwsem); |
a0d092fc PP |
460 | return err; |
461 | } | |
462 | ||
2cafed30 DB |
463 | static int msgctl_nolock(struct ipc_namespace *ns, int msqid, |
464 | int cmd, int version, void __user *buf) | |
a0d092fc | 465 | { |
2cafed30 | 466 | int err; |
5a06a363 | 467 | struct msg_queue *msq; |
1da177e4 LT |
468 | |
469 | switch (cmd) { | |
5a06a363 IM |
470 | case IPC_INFO: |
471 | case MSG_INFO: | |
472 | { | |
1da177e4 LT |
473 | struct msginfo msginfo; |
474 | int max_id; | |
5a06a363 | 475 | |
1da177e4 LT |
476 | if (!buf) |
477 | return -EFAULT; | |
2cafed30 | 478 | |
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; | |
d9a605e4 | 494 | down_read(&msg_ids(ns).rwsem); |
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)); |
d9a605e4 | 505 | up_read(&msg_ids(ns).rwsem); |
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 | } |
2cafed30 DB |
510 | |
511 | case MSG_STAT: | |
1da177e4 LT |
512 | case IPC_STAT: |
513 | { | |
514 | struct msqid64_ds tbuf; | |
515 | int success_return; | |
5a06a363 | 516 | |
1da177e4 LT |
517 | if (!buf) |
518 | return -EFAULT; | |
1da177e4 | 519 | |
ac0ba20e DB |
520 | memset(&tbuf, 0, sizeof(tbuf)); |
521 | ||
522 | rcu_read_lock(); | |
5a06a363 | 523 | if (cmd == MSG_STAT) { |
ac0ba20e DB |
524 | msq = msq_obtain_object(ns, msqid); |
525 | if (IS_ERR(msq)) { | |
526 | err = PTR_ERR(msq); | |
527 | goto out_unlock; | |
528 | } | |
7ca7e564 | 529 | success_return = msq->q_perm.id; |
1da177e4 | 530 | } else { |
ac0ba20e DB |
531 | msq = msq_obtain_object_check(ns, msqid); |
532 | if (IS_ERR(msq)) { | |
533 | err = PTR_ERR(msq); | |
534 | goto out_unlock; | |
535 | } | |
1da177e4 LT |
536 | success_return = 0; |
537 | } | |
ac0ba20e | 538 | |
1da177e4 | 539 | err = -EACCES; |
b0e77598 | 540 | if (ipcperms(ns, &msq->q_perm, S_IRUGO)) |
1da177e4 LT |
541 | goto out_unlock; |
542 | ||
543 | err = security_msg_queue_msgctl(msq, cmd); | |
544 | if (err) | |
545 | goto out_unlock; | |
546 | ||
547 | kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm); | |
548 | tbuf.msg_stime = msq->q_stime; | |
549 | tbuf.msg_rtime = msq->q_rtime; | |
550 | tbuf.msg_ctime = msq->q_ctime; | |
551 | tbuf.msg_cbytes = msq->q_cbytes; | |
552 | tbuf.msg_qnum = msq->q_qnum; | |
553 | tbuf.msg_qbytes = msq->q_qbytes; | |
554 | tbuf.msg_lspid = msq->q_lspid; | |
555 | tbuf.msg_lrpid = msq->q_lrpid; | |
ac0ba20e DB |
556 | rcu_read_unlock(); |
557 | ||
1da177e4 LT |
558 | if (copy_msqid_to_user(buf, &tbuf, version)) |
559 | return -EFAULT; | |
560 | return success_return; | |
561 | } | |
2cafed30 | 562 | |
1da177e4 | 563 | default: |
2cafed30 | 564 | return -EINVAL; |
1da177e4 LT |
565 | } |
566 | ||
2cafed30 | 567 | return err; |
1da177e4 | 568 | out_unlock: |
ac0ba20e | 569 | rcu_read_unlock(); |
1da177e4 LT |
570 | return err; |
571 | } | |
572 | ||
2cafed30 DB |
573 | SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) |
574 | { | |
575 | int version; | |
576 | struct ipc_namespace *ns; | |
577 | ||
578 | if (msqid < 0 || cmd < 0) | |
579 | return -EINVAL; | |
580 | ||
581 | version = ipc_parse_version(&cmd); | |
582 | ns = current->nsproxy->ipc_ns; | |
583 | ||
584 | switch (cmd) { | |
585 | case IPC_INFO: | |
586 | case MSG_INFO: | |
587 | case MSG_STAT: /* msqid is an index rather than a msg queue id */ | |
588 | case IPC_STAT: | |
589 | return msgctl_nolock(ns, msqid, cmd, version, buf); | |
590 | case IPC_SET: | |
591 | case IPC_RMID: | |
592 | return msgctl_down(ns, msqid, cmd, buf, version); | |
593 | default: | |
594 | return -EINVAL; | |
595 | } | |
596 | } | |
597 | ||
5a06a363 | 598 | static int testmsg(struct msg_msg *msg, long type, int mode) |
1da177e4 | 599 | { |
46c0a8ca PM |
600 | switch (mode) { |
601 | case SEARCH_ANY: | |
602 | case SEARCH_NUMBER: | |
603 | return 1; | |
604 | case SEARCH_LESSEQUAL: | |
605 | if (msg->m_type <= type) | |
606 | return 1; | |
607 | break; | |
608 | case SEARCH_EQUAL: | |
609 | if (msg->m_type == type) | |
1da177e4 | 610 | return 1; |
46c0a8ca PM |
611 | break; |
612 | case SEARCH_NOTEQUAL: | |
613 | if (msg->m_type != type) | |
614 | return 1; | |
615 | break; | |
1da177e4 LT |
616 | } |
617 | return 0; | |
618 | } | |
619 | ||
ee51636c SAS |
620 | static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg, |
621 | struct wake_q_head *wake_q) | |
1da177e4 | 622 | { |
41239fe8 | 623 | struct msg_receiver *msr, *t; |
5a06a363 | 624 | |
41239fe8 | 625 | list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { |
5a06a363 IM |
626 | if (testmsg(msg, msr->r_msgtype, msr->r_mode) && |
627 | !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, | |
628 | msr->r_msgtype, msr->r_mode)) { | |
629 | ||
1da177e4 | 630 | list_del(&msr->r_list); |
5a06a363 | 631 | if (msr->r_maxsize < msg->m_ts) { |
ee51636c SAS |
632 | wake_q_add(wake_q, msr->r_tsk); |
633 | WRITE_ONCE(msr->r_msg, ERR_PTR(-E2BIG)); | |
1da177e4 | 634 | } else { |
b488893a | 635 | msq->q_lrpid = task_pid_vnr(msr->r_tsk); |
1da177e4 | 636 | msq->q_rtime = get_seconds(); |
5a06a363 | 637 | |
ee51636c SAS |
638 | wake_q_add(wake_q, msr->r_tsk); |
639 | WRITE_ONCE(msr->r_msg, msg); | |
1da177e4 LT |
640 | return 1; |
641 | } | |
642 | } | |
643 | } | |
ffa571da | 644 | |
1da177e4 LT |
645 | return 0; |
646 | } | |
647 | ||
651971cb | 648 | long do_msgsnd(int msqid, long mtype, void __user *mtext, |
649 | size_t msgsz, int msgflg) | |
1da177e4 LT |
650 | { |
651 | struct msg_queue *msq; | |
652 | struct msg_msg *msg; | |
1da177e4 | 653 | int err; |
1e786937 | 654 | struct ipc_namespace *ns; |
194a6b5b | 655 | DEFINE_WAKE_Q(wake_q); |
1e786937 KK |
656 | |
657 | ns = current->nsproxy->ipc_ns; | |
5a06a363 | 658 | |
1e786937 | 659 | if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0) |
1da177e4 | 660 | return -EINVAL; |
1da177e4 LT |
661 | if (mtype < 1) |
662 | return -EINVAL; | |
663 | ||
651971cb | 664 | msg = load_msg(mtext, msgsz); |
5a06a363 | 665 | if (IS_ERR(msg)) |
1da177e4 LT |
666 | return PTR_ERR(msg); |
667 | ||
668 | msg->m_type = mtype; | |
669 | msg->m_ts = msgsz; | |
670 | ||
3dd1f784 DB |
671 | rcu_read_lock(); |
672 | msq = msq_obtain_object_check(ns, msqid); | |
023a5355 ND |
673 | if (IS_ERR(msq)) { |
674 | err = PTR_ERR(msq); | |
3dd1f784 | 675 | goto out_unlock1; |
023a5355 | 676 | } |
1da177e4 | 677 | |
bebcb928 MS |
678 | ipc_lock_object(&msq->q_perm); |
679 | ||
1da177e4 LT |
680 | for (;;) { |
681 | struct msg_sender s; | |
682 | ||
5a06a363 | 683 | err = -EACCES; |
b0e77598 | 684 | if (ipcperms(ns, &msq->q_perm, S_IWUGO)) |
bebcb928 | 685 | goto out_unlock0; |
1da177e4 | 686 | |
4271b05a | 687 | /* raced with RMID? */ |
0f3d2b01 | 688 | if (!ipc_valid_object(&msq->q_perm)) { |
4271b05a DB |
689 | err = -EIDRM; |
690 | goto out_unlock0; | |
691 | } | |
692 | ||
1da177e4 LT |
693 | err = security_msg_queue_msgsnd(msq, msg, msgflg); |
694 | if (err) | |
bebcb928 | 695 | goto out_unlock0; |
1da177e4 | 696 | |
ed27f912 | 697 | if (msg_fits_inqueue(msq, msgsz)) |
1da177e4 | 698 | break; |
1da177e4 LT |
699 | |
700 | /* queue full, wait: */ | |
5a06a363 IM |
701 | if (msgflg & IPC_NOWAIT) { |
702 | err = -EAGAIN; | |
bebcb928 | 703 | goto out_unlock0; |
1da177e4 | 704 | } |
3dd1f784 | 705 | |
ffa571da | 706 | /* enqueue the sender and prepare to block */ |
ed27f912 | 707 | ss_add(msq, &s, msgsz); |
6062a8dc | 708 | |
dba4cdd3 | 709 | if (!ipc_rcu_getref(&msq->q_perm)) { |
6062a8dc | 710 | err = -EIDRM; |
3dd1f784 | 711 | goto out_unlock0; |
6062a8dc RR |
712 | } |
713 | ||
3dd1f784 DB |
714 | ipc_unlock_object(&msq->q_perm); |
715 | rcu_read_unlock(); | |
1da177e4 LT |
716 | schedule(); |
717 | ||
3dd1f784 DB |
718 | rcu_read_lock(); |
719 | ipc_lock_object(&msq->q_perm); | |
720 | ||
dba4cdd3 | 721 | ipc_rcu_putref(&msq->q_perm, msg_rcu_free); |
0f3d2b01 RA |
722 | /* raced with RMID? */ |
723 | if (!ipc_valid_object(&msq->q_perm)) { | |
1da177e4 | 724 | err = -EIDRM; |
3dd1f784 | 725 | goto out_unlock0; |
1da177e4 LT |
726 | } |
727 | ss_del(&s); | |
5a06a363 | 728 | |
1da177e4 | 729 | if (signal_pending(current)) { |
5a06a363 | 730 | err = -ERESTARTNOHAND; |
3dd1f784 | 731 | goto out_unlock0; |
1da177e4 | 732 | } |
3dd1f784 | 733 | |
1da177e4 | 734 | } |
ed27f912 | 735 | |
b488893a | 736 | msq->q_lspid = task_tgid_vnr(current); |
1da177e4 LT |
737 | msq->q_stime = get_seconds(); |
738 | ||
ee51636c | 739 | if (!pipelined_send(msq, msg, &wake_q)) { |
25985edc | 740 | /* no one is waiting for this message, enqueue it */ |
5a06a363 | 741 | list_add_tail(&msg->m_list, &msq->q_messages); |
1da177e4 LT |
742 | msq->q_cbytes += msgsz; |
743 | msq->q_qnum++; | |
3ac88a41 KK |
744 | atomic_add(msgsz, &ns->msg_bytes); |
745 | atomic_inc(&ns->msg_hdrs); | |
1da177e4 | 746 | } |
5a06a363 | 747 | |
1da177e4 LT |
748 | err = 0; |
749 | msg = NULL; | |
750 | ||
3dd1f784 DB |
751 | out_unlock0: |
752 | ipc_unlock_object(&msq->q_perm); | |
ee51636c | 753 | wake_up_q(&wake_q); |
3dd1f784 DB |
754 | out_unlock1: |
755 | rcu_read_unlock(); | |
5a06a363 | 756 | if (msg != NULL) |
1da177e4 LT |
757 | free_msg(msg); |
758 | return err; | |
759 | } | |
760 | ||
e48fbb69 HC |
761 | SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, |
762 | int, msgflg) | |
651971cb | 763 | { |
764 | long mtype; | |
765 | ||
766 | if (get_user(mtype, &msgp->mtype)) | |
767 | return -EFAULT; | |
768 | return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg); | |
769 | } | |
770 | ||
5a06a363 | 771 | static inline int convert_mode(long *msgtyp, int msgflg) |
1da177e4 | 772 | { |
8ac6ed58 PH |
773 | if (msgflg & MSG_COPY) |
774 | return SEARCH_NUMBER; | |
5a06a363 | 775 | /* |
1da177e4 LT |
776 | * find message of correct type. |
777 | * msgtyp = 0 => get first. | |
778 | * msgtyp > 0 => get first message of matching type. | |
5a06a363 | 779 | * msgtyp < 0 => get message with least type must be < abs(msgtype). |
1da177e4 | 780 | */ |
5a06a363 | 781 | if (*msgtyp == 0) |
1da177e4 | 782 | return SEARCH_ANY; |
5a06a363 | 783 | if (*msgtyp < 0) { |
99989835 JS |
784 | if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */ |
785 | *msgtyp = LONG_MAX; | |
786 | else | |
787 | *msgtyp = -*msgtyp; | |
1da177e4 LT |
788 | return SEARCH_LESSEQUAL; |
789 | } | |
5a06a363 | 790 | if (msgflg & MSG_EXCEPT) |
1da177e4 LT |
791 | return SEARCH_NOTEQUAL; |
792 | return SEARCH_EQUAL; | |
793 | } | |
794 | ||
f9dd87f4 SK |
795 | static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) |
796 | { | |
797 | struct msgbuf __user *msgp = dest; | |
798 | size_t msgsz; | |
799 | ||
800 | if (put_user(msg->m_type, &msgp->mtype)) | |
801 | return -EFAULT; | |
802 | ||
803 | msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; | |
804 | if (store_msg(msgp->mtext, msg, msgsz)) | |
805 | return -EFAULT; | |
806 | return msgsz; | |
807 | } | |
808 | ||
4a674f34 | 809 | #ifdef CONFIG_CHECKPOINT_RESTORE |
3fcfe786 SK |
810 | /* |
811 | * This function creates new kernel message structure, large enough to store | |
812 | * bufsz message bytes. | |
813 | */ | |
8ac6ed58 | 814 | static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) |
4a674f34 SK |
815 | { |
816 | struct msg_msg *copy; | |
817 | ||
4a674f34 SK |
818 | /* |
819 | * Create dummy message to copy real message to. | |
820 | */ | |
821 | copy = load_msg(buf, bufsz); | |
822 | if (!IS_ERR(copy)) | |
823 | copy->m_ts = bufsz; | |
824 | return copy; | |
825 | } | |
826 | ||
85398aa8 | 827 | static inline void free_copy(struct msg_msg *copy) |
4a674f34 | 828 | { |
85398aa8 | 829 | if (copy) |
4a674f34 SK |
830 | free_msg(copy); |
831 | } | |
832 | #else | |
8ac6ed58 | 833 | static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) |
b30efe27 SK |
834 | { |
835 | return ERR_PTR(-ENOSYS); | |
836 | } | |
837 | ||
85398aa8 SK |
838 | static inline void free_copy(struct msg_msg *copy) |
839 | { | |
840 | } | |
4a674f34 SK |
841 | #endif |
842 | ||
daaf74cf PH |
843 | static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode) |
844 | { | |
368ae537 | 845 | struct msg_msg *msg, *found = NULL; |
daaf74cf PH |
846 | long count = 0; |
847 | ||
848 | list_for_each_entry(msg, &msq->q_messages, m_list) { | |
849 | if (testmsg(msg, *msgtyp, mode) && | |
850 | !security_msg_queue_msgrcv(msq, msg, current, | |
851 | *msgtyp, mode)) { | |
852 | if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) { | |
853 | *msgtyp = msg->m_type - 1; | |
368ae537 | 854 | found = msg; |
daaf74cf PH |
855 | } else if (mode == SEARCH_NUMBER) { |
856 | if (*msgtyp == count) | |
857 | return msg; | |
858 | } else | |
859 | return msg; | |
860 | count++; | |
861 | } | |
862 | } | |
863 | ||
368ae537 | 864 | return found ?: ERR_PTR(-EAGAIN); |
daaf74cf PH |
865 | } |
866 | ||
41a0d523 | 867 | long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg, |
f9dd87f4 | 868 | long (*msg_handler)(void __user *, struct msg_msg *, size_t)) |
1da177e4 | 869 | { |
1da177e4 | 870 | int mode; |
41a0d523 | 871 | struct msg_queue *msq; |
1e786937 | 872 | struct ipc_namespace *ns; |
41a0d523 | 873 | struct msg_msg *msg, *copy = NULL; |
194a6b5b | 874 | DEFINE_WAKE_Q(wake_q); |
1da177e4 | 875 | |
88b9e456 PH |
876 | ns = current->nsproxy->ipc_ns; |
877 | ||
f9dd87f4 | 878 | if (msqid < 0 || (long) bufsz < 0) |
1da177e4 | 879 | return -EINVAL; |
41a0d523 | 880 | |
4a674f34 | 881 | if (msgflg & MSG_COPY) { |
4f87dac3 MK |
882 | if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT)) |
883 | return -EINVAL; | |
8ac6ed58 | 884 | copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); |
4a674f34 SK |
885 | if (IS_ERR(copy)) |
886 | return PTR_ERR(copy); | |
887 | } | |
5a06a363 | 888 | mode = convert_mode(&msgtyp, msgflg); |
1da177e4 | 889 | |
41a0d523 DB |
890 | rcu_read_lock(); |
891 | msq = msq_obtain_object_check(ns, msqid); | |
4a674f34 | 892 | if (IS_ERR(msq)) { |
41a0d523 | 893 | rcu_read_unlock(); |
85398aa8 | 894 | free_copy(copy); |
023a5355 | 895 | return PTR_ERR(msq); |
4a674f34 | 896 | } |
1da177e4 LT |
897 | |
898 | for (;;) { | |
899 | struct msg_receiver msr_d; | |
1da177e4 LT |
900 | |
901 | msg = ERR_PTR(-EACCES); | |
b0e77598 | 902 | if (ipcperms(ns, &msq->q_perm, S_IRUGO)) |
41a0d523 | 903 | goto out_unlock1; |
1da177e4 | 904 | |
41a0d523 | 905 | ipc_lock_object(&msq->q_perm); |
4271b05a DB |
906 | |
907 | /* raced with RMID? */ | |
0f3d2b01 | 908 | if (!ipc_valid_object(&msq->q_perm)) { |
4271b05a DB |
909 | msg = ERR_PTR(-EIDRM); |
910 | goto out_unlock0; | |
911 | } | |
912 | ||
daaf74cf | 913 | msg = find_msg(msq, &msgtyp, mode); |
5a06a363 IM |
914 | if (!IS_ERR(msg)) { |
915 | /* | |
916 | * Found a suitable message. | |
917 | * Unlink it from the queue. | |
918 | */ | |
f9dd87f4 | 919 | if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { |
1da177e4 | 920 | msg = ERR_PTR(-E2BIG); |
41a0d523 | 921 | goto out_unlock0; |
1da177e4 | 922 | } |
3fcfe786 SK |
923 | /* |
924 | * If we are copying, then do not unlink message and do | |
925 | * not update queue parameters. | |
926 | */ | |
852028af PH |
927 | if (msgflg & MSG_COPY) { |
928 | msg = copy_msg(msg, copy); | |
41a0d523 | 929 | goto out_unlock0; |
852028af | 930 | } |
41a0d523 | 931 | |
1da177e4 LT |
932 | list_del(&msg->m_list); |
933 | msq->q_qnum--; | |
934 | msq->q_rtime = get_seconds(); | |
b488893a | 935 | msq->q_lrpid = task_tgid_vnr(current); |
1da177e4 | 936 | msq->q_cbytes -= msg->m_ts; |
3ac88a41 KK |
937 | atomic_sub(msg->m_ts, &ns->msg_bytes); |
938 | atomic_dec(&ns->msg_hdrs); | |
ed27f912 | 939 | ss_wakeup(msq, &wake_q, false); |
41a0d523 DB |
940 | |
941 | goto out_unlock0; | |
1da177e4 | 942 | } |
41a0d523 | 943 | |
1da177e4 LT |
944 | /* No message waiting. Wait for a message */ |
945 | if (msgflg & IPC_NOWAIT) { | |
946 | msg = ERR_PTR(-ENOMSG); | |
41a0d523 | 947 | goto out_unlock0; |
1da177e4 | 948 | } |
41a0d523 | 949 | |
5a06a363 | 950 | list_add_tail(&msr_d.r_list, &msq->q_receivers); |
1da177e4 LT |
951 | msr_d.r_tsk = current; |
952 | msr_d.r_msgtype = msgtyp; | |
953 | msr_d.r_mode = mode; | |
5a06a363 | 954 | if (msgflg & MSG_NOERROR) |
1da177e4 | 955 | msr_d.r_maxsize = INT_MAX; |
5a06a363 | 956 | else |
f9dd87f4 | 957 | msr_d.r_maxsize = bufsz; |
1da177e4 | 958 | msr_d.r_msg = ERR_PTR(-EAGAIN); |
f75a2f35 | 959 | __set_current_state(TASK_INTERRUPTIBLE); |
1da177e4 | 960 | |
41a0d523 DB |
961 | ipc_unlock_object(&msq->q_perm); |
962 | rcu_read_unlock(); | |
1da177e4 LT |
963 | schedule(); |
964 | ||
ee51636c SAS |
965 | /* |
966 | * Lockless receive, part 1: | |
967 | * We don't hold a reference to the queue and getting a | |
968 | * reference would defeat the idea of a lockless operation, | |
969 | * thus the code relies on rcu to guarantee the existence of | |
970 | * msq: | |
1da177e4 LT |
971 | * Prior to destruction, expunge_all(-EIRDM) changes r_msg. |
972 | * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. | |
1da177e4 LT |
973 | */ |
974 | rcu_read_lock(); | |
975 | ||
ee51636c SAS |
976 | /* |
977 | * Lockless receive, part 2: | |
978 | * The work in pipelined_send() and expunge_all(): | |
979 | * - Set pointer to message | |
980 | * - Queue the receiver task for later wakeup | |
981 | * - Wake up the process after the lock is dropped. | |
ff35e5ef | 982 | * |
ee51636c SAS |
983 | * Should the process wake up before this wakeup (due to a |
984 | * signal) it will either see the message and continue ... | |
1da177e4 | 985 | */ |
ee51636c | 986 | msg = READ_ONCE(msr_d.r_msg); |
41a0d523 DB |
987 | if (msg != ERR_PTR(-EAGAIN)) |
988 | goto out_unlock1; | |
1da177e4 | 989 | |
ee51636c SAS |
990 | /* |
991 | * ... or see -EAGAIN, acquire the lock to check the message | |
992 | * again. | |
993 | */ | |
41a0d523 | 994 | ipc_lock_object(&msq->q_perm); |
1da177e4 | 995 | |
ee51636c | 996 | msg = msr_d.r_msg; |
5a06a363 | 997 | if (msg != ERR_PTR(-EAGAIN)) |
41a0d523 | 998 | goto out_unlock0; |
1da177e4 LT |
999 | |
1000 | list_del(&msr_d.r_list); | |
1001 | if (signal_pending(current)) { | |
1002 | msg = ERR_PTR(-ERESTARTNOHAND); | |
41a0d523 | 1003 | goto out_unlock0; |
1da177e4 | 1004 | } |
41a0d523 DB |
1005 | |
1006 | ipc_unlock_object(&msq->q_perm); | |
1da177e4 | 1007 | } |
41a0d523 DB |
1008 | |
1009 | out_unlock0: | |
1010 | ipc_unlock_object(&msq->q_perm); | |
e3658538 | 1011 | wake_up_q(&wake_q); |
41a0d523 DB |
1012 | out_unlock1: |
1013 | rcu_read_unlock(); | |
4a674f34 | 1014 | if (IS_ERR(msg)) { |
85398aa8 | 1015 | free_copy(copy); |
5a06a363 | 1016 | return PTR_ERR(msg); |
4a674f34 | 1017 | } |
1da177e4 | 1018 | |
f9dd87f4 | 1019 | bufsz = msg_handler(buf, msg, bufsz); |
1da177e4 | 1020 | free_msg(msg); |
5a06a363 | 1021 | |
f9dd87f4 | 1022 | return bufsz; |
1da177e4 LT |
1023 | } |
1024 | ||
e48fbb69 HC |
1025 | SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, |
1026 | long, msgtyp, int, msgflg) | |
651971cb | 1027 | { |
f9dd87f4 | 1028 | return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill); |
651971cb | 1029 | } |
1030 | ||
3440a6bd DB |
1031 | |
1032 | void msg_init_ns(struct ipc_namespace *ns) | |
1033 | { | |
1034 | ns->msg_ctlmax = MSGMAX; | |
1035 | ns->msg_ctlmnb = MSGMNB; | |
0050ee05 | 1036 | ns->msg_ctlmni = MSGMNI; |
3440a6bd DB |
1037 | |
1038 | atomic_set(&ns->msg_bytes, 0); | |
1039 | atomic_set(&ns->msg_hdrs, 0); | |
1040 | ipc_init_ids(&ns->ids[IPC_MSG_IDS]); | |
1041 | } | |
1042 | ||
1043 | #ifdef CONFIG_IPC_NS | |
1044 | void msg_exit_ns(struct ipc_namespace *ns) | |
1045 | { | |
1046 | free_ipcs(ns, &msg_ids(ns), freeque); | |
1047 | idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr); | |
1048 | } | |
1049 | #endif | |
1050 | ||
1da177e4 | 1051 | #ifdef CONFIG_PROC_FS |
19b4946c | 1052 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it) |
1da177e4 | 1053 | { |
1efdb69b | 1054 | struct user_namespace *user_ns = seq_user_ns(s); |
19b4946c MW |
1055 | struct msg_queue *msq = it; |
1056 | ||
7f032d6e JP |
1057 | seq_printf(s, |
1058 | "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n", | |
1059 | msq->q_perm.key, | |
1060 | msq->q_perm.id, | |
1061 | msq->q_perm.mode, | |
1062 | msq->q_cbytes, | |
1063 | msq->q_qnum, | |
1064 | msq->q_lspid, | |
1065 | msq->q_lrpid, | |
1066 | from_kuid_munged(user_ns, msq->q_perm.uid), | |
1067 | from_kgid_munged(user_ns, msq->q_perm.gid), | |
1068 | from_kuid_munged(user_ns, msq->q_perm.cuid), | |
1069 | from_kgid_munged(user_ns, msq->q_perm.cgid), | |
1070 | msq->q_stime, | |
1071 | msq->q_rtime, | |
1072 | msq->q_ctime); | |
1073 | ||
1074 | return 0; | |
1da177e4 LT |
1075 | } |
1076 | #endif | |
3440a6bd DB |
1077 | |
1078 | void __init msg_init(void) | |
1079 | { | |
1080 | msg_init_ns(&init_ipc_ns); | |
1081 | ||
3440a6bd DB |
1082 | ipc_init_proc_interface("sysvipc/msg", |
1083 | " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", | |
1084 | IPC_MSG_IDS, sysvipc_msg_proc_show); | |
1085 | } |