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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 | ||
f4566f04 ND |
112 | /** |
113 | * newque - Create a new msg queue | |
114 | * @ns: namespace | |
115 | * @params: ptr to the structure that contains the key and msgflg | |
116 | * | |
d9a605e4 | 117 | * Called with msg_ids.rwsem held (writer) |
f4566f04 | 118 | */ |
7748dbfa | 119 | static int newque(struct ipc_namespace *ns, struct ipc_params *params) |
1da177e4 | 120 | { |
1da177e4 | 121 | struct msg_queue *msq; |
5a06a363 | 122 | int id, retval; |
7748dbfa ND |
123 | key_t key = params->key; |
124 | int msgflg = params->flg; | |
1da177e4 | 125 | |
dba4cdd3 MS |
126 | BUILD_BUG_ON(offsetof(struct msg_queue, q_perm) != 0); |
127 | ||
128 | msq = container_of(ipc_rcu_alloc(sizeof(*msq)), struct msg_queue, | |
129 | q_perm); | |
5a06a363 | 130 | if (!msq) |
1da177e4 LT |
131 | return -ENOMEM; |
132 | ||
5a06a363 | 133 | msq->q_perm.mode = msgflg & S_IRWXUGO; |
1da177e4 LT |
134 | msq->q_perm.key = key; |
135 | ||
136 | msq->q_perm.security = NULL; | |
137 | retval = security_msg_queue_alloc(msq); | |
138 | if (retval) { | |
9ef5932f | 139 | __msg_free(msq); |
1da177e4 LT |
140 | return retval; |
141 | } | |
142 | ||
1da177e4 LT |
143 | msq->q_stime = msq->q_rtime = 0; |
144 | msq->q_ctime = get_seconds(); | |
145 | msq->q_cbytes = msq->q_qnum = 0; | |
1e786937 | 146 | msq->q_qbytes = ns->msg_ctlmnb; |
1da177e4 LT |
147 | msq->q_lspid = msq->q_lrpid = 0; |
148 | INIT_LIST_HEAD(&msq->q_messages); | |
149 | INIT_LIST_HEAD(&msq->q_receivers); | |
150 | INIT_LIST_HEAD(&msq->q_senders); | |
7ca7e564 | 151 | |
b9a53227 LT |
152 | /* ipc_addid() locks msq upon success. */ |
153 | id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); | |
154 | if (id < 0) { | |
dba4cdd3 | 155 | ipc_rcu_putref(&msq->q_perm, msg_rcu_free); |
b9a53227 LT |
156 | return id; |
157 | } | |
158 | ||
cf9d5d78 | 159 | ipc_unlock_object(&msq->q_perm); |
dbfcd91f | 160 | rcu_read_unlock(); |
1da177e4 | 161 | |
7ca7e564 | 162 | return msq->q_perm.id; |
1da177e4 LT |
163 | } |
164 | ||
ed27f912 DB |
165 | static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz) |
166 | { | |
167 | return msgsz + msq->q_cbytes <= msq->q_qbytes && | |
168 | 1 + msq->q_qnum <= msq->q_qbytes; | |
169 | } | |
170 | ||
171 | static inline void ss_add(struct msg_queue *msq, | |
172 | struct msg_sender *mss, size_t msgsz) | |
1da177e4 | 173 | { |
5a06a363 | 174 | mss->tsk = current; |
ed27f912 | 175 | mss->msgsz = msgsz; |
f75a2f35 | 176 | __set_current_state(TASK_INTERRUPTIBLE); |
5a06a363 | 177 | list_add_tail(&mss->list, &msq->q_senders); |
1da177e4 LT |
178 | } |
179 | ||
5a06a363 | 180 | static inline void ss_del(struct msg_sender *mss) |
1da177e4 | 181 | { |
ed27f912 | 182 | if (mss->list.next) |
1da177e4 LT |
183 | list_del(&mss->list); |
184 | } | |
185 | ||
ed27f912 | 186 | static void ss_wakeup(struct msg_queue *msq, |
d0d6a2a9 | 187 | struct wake_q_head *wake_q, bool kill) |
1da177e4 | 188 | { |
41239fe8 | 189 | struct msg_sender *mss, *t; |
ed27f912 DB |
190 | struct task_struct *stop_tsk = NULL; |
191 | struct list_head *h = &msq->q_senders; | |
1da177e4 | 192 | |
41239fe8 | 193 | list_for_each_entry_safe(mss, t, h, list) { |
5a06a363 IM |
194 | if (kill) |
195 | mss->list.next = NULL; | |
ed27f912 DB |
196 | |
197 | /* | |
198 | * Stop at the first task we don't wakeup, | |
199 | * we've already iterated the original | |
200 | * sender queue. | |
201 | */ | |
202 | else if (stop_tsk == mss->tsk) | |
203 | break; | |
204 | /* | |
205 | * We are not in an EIDRM scenario here, therefore | |
206 | * verify that we really need to wakeup the task. | |
207 | * To maintain current semantics and wakeup order, | |
208 | * move the sender to the tail on behalf of the | |
209 | * blocked task. | |
210 | */ | |
211 | else if (!msg_fits_inqueue(msq, mss->msgsz)) { | |
212 | if (!stop_tsk) | |
213 | stop_tsk = mss->tsk; | |
214 | ||
215 | list_move_tail(&mss->list, &msq->q_senders); | |
216 | continue; | |
217 | } | |
218 | ||
e3658538 | 219 | wake_q_add(wake_q, mss->tsk); |
1da177e4 LT |
220 | } |
221 | } | |
222 | ||
ee51636c SAS |
223 | static void expunge_all(struct msg_queue *msq, int res, |
224 | struct wake_q_head *wake_q) | |
1da177e4 | 225 | { |
41239fe8 | 226 | struct msg_receiver *msr, *t; |
5a06a363 | 227 | |
41239fe8 | 228 | list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { |
ee51636c SAS |
229 | wake_q_add(wake_q, msr->r_tsk); |
230 | WRITE_ONCE(msr->r_msg, ERR_PTR(res)); | |
1da177e4 LT |
231 | } |
232 | } | |
5a06a363 IM |
233 | |
234 | /* | |
235 | * freeque() wakes up waiters on the sender and receiver waiting queue, | |
f4566f04 ND |
236 | * removes the message queue from message queue ID IDR, and cleans up all the |
237 | * messages associated with this queue. | |
1da177e4 | 238 | * |
d9a605e4 DB |
239 | * msg_ids.rwsem (writer) and the spinlock for this message queue are held |
240 | * before freeque() is called. msg_ids.rwsem remains locked on exit. | |
1da177e4 | 241 | */ |
01b8b07a | 242 | static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) |
1da177e4 | 243 | { |
41239fe8 | 244 | struct msg_msg *msg, *t; |
01b8b07a | 245 | struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); |
194a6b5b | 246 | DEFINE_WAKE_Q(wake_q); |
1da177e4 | 247 | |
ee51636c | 248 | expunge_all(msq, -EIDRM, &wake_q); |
ed27f912 | 249 | ss_wakeup(msq, &wake_q, true); |
7ca7e564 | 250 | msg_rmid(ns, msq); |
4718787d | 251 | ipc_unlock_object(&msq->q_perm); |
ee51636c | 252 | wake_up_q(&wake_q); |
4718787d | 253 | rcu_read_unlock(); |
5a06a363 | 254 | |
41239fe8 | 255 | list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) { |
3ac88a41 | 256 | atomic_dec(&ns->msg_hdrs); |
1da177e4 LT |
257 | free_msg(msg); |
258 | } | |
3ac88a41 | 259 | atomic_sub(msq->q_cbytes, &ns->msg_bytes); |
dba4cdd3 | 260 | ipc_rcu_putref(&msq->q_perm, msg_rcu_free); |
1da177e4 LT |
261 | } |
262 | ||
f4566f04 | 263 | /* |
d9a605e4 | 264 | * Called with msg_ids.rwsem and ipcp locked. |
f4566f04 | 265 | */ |
03f02c76 | 266 | static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg) |
7748dbfa | 267 | { |
03f02c76 ND |
268 | struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); |
269 | ||
270 | return security_msg_queue_associate(msq, msgflg); | |
7748dbfa ND |
271 | } |
272 | ||
e48fbb69 | 273 | SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg) |
1da177e4 | 274 | { |
1e786937 | 275 | struct ipc_namespace *ns; |
eb66ec44 MK |
276 | static const struct ipc_ops msg_ops = { |
277 | .getnew = newque, | |
278 | .associate = msg_security, | |
279 | }; | |
7748dbfa | 280 | struct ipc_params msg_params; |
1e786937 KK |
281 | |
282 | ns = current->nsproxy->ipc_ns; | |
7ca7e564 | 283 | |
7748dbfa ND |
284 | msg_params.key = key; |
285 | msg_params.flg = msgflg; | |
5a06a363 | 286 | |
7748dbfa | 287 | return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params); |
1da177e4 LT |
288 | } |
289 | ||
5a06a363 IM |
290 | static inline unsigned long |
291 | copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) | |
1da177e4 | 292 | { |
239521f3 | 293 | switch (version) { |
1da177e4 | 294 | case IPC_64: |
5a06a363 | 295 | return copy_to_user(buf, in, sizeof(*in)); |
1da177e4 | 296 | case IPC_OLD: |
5a06a363 | 297 | { |
1da177e4 LT |
298 | struct msqid_ds out; |
299 | ||
5a06a363 | 300 | memset(&out, 0, sizeof(out)); |
1da177e4 LT |
301 | |
302 | ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); | |
303 | ||
304 | out.msg_stime = in->msg_stime; | |
305 | out.msg_rtime = in->msg_rtime; | |
306 | out.msg_ctime = in->msg_ctime; | |
307 | ||
4be929be AD |
308 | if (in->msg_cbytes > USHRT_MAX) |
309 | out.msg_cbytes = USHRT_MAX; | |
1da177e4 LT |
310 | else |
311 | out.msg_cbytes = in->msg_cbytes; | |
312 | out.msg_lcbytes = in->msg_cbytes; | |
313 | ||
4be929be AD |
314 | if (in->msg_qnum > USHRT_MAX) |
315 | out.msg_qnum = USHRT_MAX; | |
1da177e4 LT |
316 | else |
317 | out.msg_qnum = in->msg_qnum; | |
318 | ||
4be929be AD |
319 | if (in->msg_qbytes > USHRT_MAX) |
320 | out.msg_qbytes = USHRT_MAX; | |
1da177e4 LT |
321 | else |
322 | out.msg_qbytes = in->msg_qbytes; | |
323 | out.msg_lqbytes = in->msg_qbytes; | |
324 | ||
325 | out.msg_lspid = in->msg_lspid; | |
326 | out.msg_lrpid = in->msg_lrpid; | |
327 | ||
5a06a363 IM |
328 | return copy_to_user(buf, &out, sizeof(out)); |
329 | } | |
1da177e4 LT |
330 | default: |
331 | return -EINVAL; | |
332 | } | |
333 | } | |
334 | ||
5a06a363 | 335 | static inline unsigned long |
016d7132 | 336 | copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version) |
1da177e4 | 337 | { |
239521f3 | 338 | switch (version) { |
1da177e4 | 339 | case IPC_64: |
016d7132 | 340 | if (copy_from_user(out, buf, sizeof(*out))) |
1da177e4 | 341 | return -EFAULT; |
1da177e4 | 342 | return 0; |
1da177e4 | 343 | case IPC_OLD: |
5a06a363 | 344 | { |
1da177e4 LT |
345 | struct msqid_ds tbuf_old; |
346 | ||
5a06a363 | 347 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) |
1da177e4 LT |
348 | return -EFAULT; |
349 | ||
239521f3 MS |
350 | out->msg_perm.uid = tbuf_old.msg_perm.uid; |
351 | out->msg_perm.gid = tbuf_old.msg_perm.gid; | |
352 | out->msg_perm.mode = tbuf_old.msg_perm.mode; | |
1da177e4 | 353 | |
5a06a363 | 354 | if (tbuf_old.msg_qbytes == 0) |
016d7132 | 355 | out->msg_qbytes = tbuf_old.msg_lqbytes; |
1da177e4 | 356 | else |
016d7132 | 357 | out->msg_qbytes = tbuf_old.msg_qbytes; |
1da177e4 LT |
358 | |
359 | return 0; | |
5a06a363 | 360 | } |
1da177e4 LT |
361 | default: |
362 | return -EINVAL; | |
363 | } | |
364 | } | |
365 | ||
a0d092fc | 366 | /* |
d9a605e4 | 367 | * This function handles some msgctl commands which require the rwsem |
a0d092fc | 368 | * to be held in write mode. |
d9a605e4 | 369 | * NOTE: no locks must be held, the rwsem is taken inside this function. |
a0d092fc PP |
370 | */ |
371 | static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, | |
372 | struct msqid_ds __user *buf, int version) | |
1da177e4 | 373 | { |
1da177e4 | 374 | struct kern_ipc_perm *ipcp; |
f1970c48 | 375 | struct msqid64_ds uninitialized_var(msqid64); |
a0d092fc PP |
376 | struct msg_queue *msq; |
377 | int err; | |
378 | ||
379 | if (cmd == IPC_SET) { | |
016d7132 | 380 | if (copy_msqid_from_user(&msqid64, buf, version)) |
a0d092fc PP |
381 | return -EFAULT; |
382 | } | |
383 | ||
d9a605e4 | 384 | down_write(&msg_ids(ns).rwsem); |
7b4cc5d8 DB |
385 | rcu_read_lock(); |
386 | ||
15724ecb DB |
387 | ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd, |
388 | &msqid64.msg_perm, msqid64.msg_qbytes); | |
7b4cc5d8 DB |
389 | if (IS_ERR(ipcp)) { |
390 | err = PTR_ERR(ipcp); | |
7b4cc5d8 DB |
391 | goto out_unlock1; |
392 | } | |
a0d092fc | 393 | |
a5f75e7f | 394 | msq = container_of(ipcp, struct msg_queue, q_perm); |
a0d092fc PP |
395 | |
396 | err = security_msg_queue_msgctl(msq, cmd); | |
397 | if (err) | |
15724ecb | 398 | goto out_unlock1; |
a0d092fc PP |
399 | |
400 | switch (cmd) { | |
401 | case IPC_RMID: | |
15724ecb | 402 | ipc_lock_object(&msq->q_perm); |
7b4cc5d8 | 403 | /* freeque unlocks the ipc object and rcu */ |
a0d092fc PP |
404 | freeque(ns, ipcp); |
405 | goto out_up; | |
406 | case IPC_SET: | |
e3658538 | 407 | { |
194a6b5b | 408 | DEFINE_WAKE_Q(wake_q); |
e3658538 | 409 | |
016d7132 | 410 | if (msqid64.msg_qbytes > ns->msg_ctlmnb && |
a0d092fc PP |
411 | !capable(CAP_SYS_RESOURCE)) { |
412 | err = -EPERM; | |
15724ecb | 413 | goto out_unlock1; |
a0d092fc PP |
414 | } |
415 | ||
15724ecb | 416 | ipc_lock_object(&msq->q_perm); |
1efdb69b EB |
417 | err = ipc_update_perm(&msqid64.msg_perm, ipcp); |
418 | if (err) | |
7b4cc5d8 | 419 | goto out_unlock0; |
1efdb69b | 420 | |
016d7132 | 421 | msq->q_qbytes = msqid64.msg_qbytes; |
a0d092fc | 422 | |
a0d092fc | 423 | msq->q_ctime = get_seconds(); |
e3658538 DB |
424 | /* |
425 | * Sleeping receivers might be excluded by | |
a0d092fc PP |
426 | * stricter permissions. |
427 | */ | |
ee51636c | 428 | expunge_all(msq, -EAGAIN, &wake_q); |
e3658538 DB |
429 | /* |
430 | * Sleeping senders might be able to send | |
a0d092fc PP |
431 | * due to a larger queue size. |
432 | */ | |
ed27f912 | 433 | ss_wakeup(msq, &wake_q, false); |
e3658538 DB |
434 | ipc_unlock_object(&msq->q_perm); |
435 | wake_up_q(&wake_q); | |
436 | ||
437 | goto out_unlock1; | |
438 | } | |
a0d092fc PP |
439 | default: |
440 | err = -EINVAL; | |
15724ecb | 441 | goto out_unlock1; |
a0d092fc | 442 | } |
7b4cc5d8 DB |
443 | |
444 | out_unlock0: | |
445 | ipc_unlock_object(&msq->q_perm); | |
446 | out_unlock1: | |
447 | rcu_read_unlock(); | |
a0d092fc | 448 | out_up: |
d9a605e4 | 449 | up_write(&msg_ids(ns).rwsem); |
a0d092fc PP |
450 | return err; |
451 | } | |
452 | ||
2cafed30 DB |
453 | static int msgctl_nolock(struct ipc_namespace *ns, int msqid, |
454 | int cmd, int version, void __user *buf) | |
a0d092fc | 455 | { |
2cafed30 | 456 | int err; |
5a06a363 | 457 | struct msg_queue *msq; |
1da177e4 LT |
458 | |
459 | switch (cmd) { | |
5a06a363 IM |
460 | case IPC_INFO: |
461 | case MSG_INFO: | |
462 | { | |
1da177e4 LT |
463 | struct msginfo msginfo; |
464 | int max_id; | |
5a06a363 | 465 | |
1da177e4 LT |
466 | if (!buf) |
467 | return -EFAULT; | |
2cafed30 | 468 | |
5a06a363 IM |
469 | /* |
470 | * We must not return kernel stack data. | |
1da177e4 LT |
471 | * due to padding, it's not enough |
472 | * to set all member fields. | |
473 | */ | |
1da177e4 LT |
474 | err = security_msg_queue_msgctl(NULL, cmd); |
475 | if (err) | |
476 | return err; | |
477 | ||
5a06a363 | 478 | memset(&msginfo, 0, sizeof(msginfo)); |
1e786937 KK |
479 | msginfo.msgmni = ns->msg_ctlmni; |
480 | msginfo.msgmax = ns->msg_ctlmax; | |
481 | msginfo.msgmnb = ns->msg_ctlmnb; | |
1da177e4 LT |
482 | msginfo.msgssz = MSGSSZ; |
483 | msginfo.msgseg = MSGSEG; | |
d9a605e4 | 484 | down_read(&msg_ids(ns).rwsem); |
1da177e4 | 485 | if (cmd == MSG_INFO) { |
1e786937 | 486 | msginfo.msgpool = msg_ids(ns).in_use; |
3ac88a41 KK |
487 | msginfo.msgmap = atomic_read(&ns->msg_hdrs); |
488 | msginfo.msgtql = atomic_read(&ns->msg_bytes); | |
1da177e4 LT |
489 | } else { |
490 | msginfo.msgmap = MSGMAP; | |
491 | msginfo.msgpool = MSGPOOL; | |
492 | msginfo.msgtql = MSGTQL; | |
493 | } | |
7ca7e564 | 494 | max_id = ipc_get_maxid(&msg_ids(ns)); |
d9a605e4 | 495 | up_read(&msg_ids(ns).rwsem); |
5a06a363 | 496 | if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) |
1da177e4 | 497 | return -EFAULT; |
5a06a363 | 498 | return (max_id < 0) ? 0 : max_id; |
1da177e4 | 499 | } |
2cafed30 DB |
500 | |
501 | case MSG_STAT: | |
1da177e4 LT |
502 | case IPC_STAT: |
503 | { | |
504 | struct msqid64_ds tbuf; | |
505 | int success_return; | |
5a06a363 | 506 | |
1da177e4 LT |
507 | if (!buf) |
508 | return -EFAULT; | |
1da177e4 | 509 | |
ac0ba20e DB |
510 | memset(&tbuf, 0, sizeof(tbuf)); |
511 | ||
512 | rcu_read_lock(); | |
5a06a363 | 513 | if (cmd == MSG_STAT) { |
ac0ba20e DB |
514 | msq = msq_obtain_object(ns, msqid); |
515 | if (IS_ERR(msq)) { | |
516 | err = PTR_ERR(msq); | |
517 | goto out_unlock; | |
518 | } | |
7ca7e564 | 519 | success_return = msq->q_perm.id; |
1da177e4 | 520 | } else { |
ac0ba20e DB |
521 | msq = msq_obtain_object_check(ns, msqid); |
522 | if (IS_ERR(msq)) { | |
523 | err = PTR_ERR(msq); | |
524 | goto out_unlock; | |
525 | } | |
1da177e4 LT |
526 | success_return = 0; |
527 | } | |
ac0ba20e | 528 | |
1da177e4 | 529 | err = -EACCES; |
b0e77598 | 530 | if (ipcperms(ns, &msq->q_perm, S_IRUGO)) |
1da177e4 LT |
531 | goto out_unlock; |
532 | ||
533 | err = security_msg_queue_msgctl(msq, cmd); | |
534 | if (err) | |
535 | goto out_unlock; | |
536 | ||
537 | kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm); | |
538 | tbuf.msg_stime = msq->q_stime; | |
539 | tbuf.msg_rtime = msq->q_rtime; | |
540 | tbuf.msg_ctime = msq->q_ctime; | |
541 | tbuf.msg_cbytes = msq->q_cbytes; | |
542 | tbuf.msg_qnum = msq->q_qnum; | |
543 | tbuf.msg_qbytes = msq->q_qbytes; | |
544 | tbuf.msg_lspid = msq->q_lspid; | |
545 | tbuf.msg_lrpid = msq->q_lrpid; | |
ac0ba20e DB |
546 | rcu_read_unlock(); |
547 | ||
1da177e4 LT |
548 | if (copy_msqid_to_user(buf, &tbuf, version)) |
549 | return -EFAULT; | |
550 | return success_return; | |
551 | } | |
2cafed30 | 552 | |
1da177e4 | 553 | default: |
2cafed30 | 554 | return -EINVAL; |
1da177e4 LT |
555 | } |
556 | ||
2cafed30 | 557 | return err; |
1da177e4 | 558 | out_unlock: |
ac0ba20e | 559 | rcu_read_unlock(); |
1da177e4 LT |
560 | return err; |
561 | } | |
562 | ||
2cafed30 DB |
563 | SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) |
564 | { | |
565 | int version; | |
566 | struct ipc_namespace *ns; | |
567 | ||
568 | if (msqid < 0 || cmd < 0) | |
569 | return -EINVAL; | |
570 | ||
571 | version = ipc_parse_version(&cmd); | |
572 | ns = current->nsproxy->ipc_ns; | |
573 | ||
574 | switch (cmd) { | |
575 | case IPC_INFO: | |
576 | case MSG_INFO: | |
577 | case MSG_STAT: /* msqid is an index rather than a msg queue id */ | |
578 | case IPC_STAT: | |
579 | return msgctl_nolock(ns, msqid, cmd, version, buf); | |
580 | case IPC_SET: | |
581 | case IPC_RMID: | |
582 | return msgctl_down(ns, msqid, cmd, buf, version); | |
583 | default: | |
584 | return -EINVAL; | |
585 | } | |
586 | } | |
587 | ||
5a06a363 | 588 | static int testmsg(struct msg_msg *msg, long type, int mode) |
1da177e4 | 589 | { |
46c0a8ca PM |
590 | switch (mode) { |
591 | case SEARCH_ANY: | |
592 | case SEARCH_NUMBER: | |
593 | return 1; | |
594 | case SEARCH_LESSEQUAL: | |
595 | if (msg->m_type <= type) | |
596 | return 1; | |
597 | break; | |
598 | case SEARCH_EQUAL: | |
599 | if (msg->m_type == type) | |
1da177e4 | 600 | return 1; |
46c0a8ca PM |
601 | break; |
602 | case SEARCH_NOTEQUAL: | |
603 | if (msg->m_type != type) | |
604 | return 1; | |
605 | break; | |
1da177e4 LT |
606 | } |
607 | return 0; | |
608 | } | |
609 | ||
ee51636c SAS |
610 | static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg, |
611 | struct wake_q_head *wake_q) | |
1da177e4 | 612 | { |
41239fe8 | 613 | struct msg_receiver *msr, *t; |
5a06a363 | 614 | |
41239fe8 | 615 | list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { |
5a06a363 IM |
616 | if (testmsg(msg, msr->r_msgtype, msr->r_mode) && |
617 | !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, | |
618 | msr->r_msgtype, msr->r_mode)) { | |
619 | ||
1da177e4 | 620 | list_del(&msr->r_list); |
5a06a363 | 621 | if (msr->r_maxsize < msg->m_ts) { |
ee51636c SAS |
622 | wake_q_add(wake_q, msr->r_tsk); |
623 | WRITE_ONCE(msr->r_msg, ERR_PTR(-E2BIG)); | |
1da177e4 | 624 | } else { |
b488893a | 625 | msq->q_lrpid = task_pid_vnr(msr->r_tsk); |
1da177e4 | 626 | msq->q_rtime = get_seconds(); |
5a06a363 | 627 | |
ee51636c SAS |
628 | wake_q_add(wake_q, msr->r_tsk); |
629 | WRITE_ONCE(msr->r_msg, msg); | |
1da177e4 LT |
630 | return 1; |
631 | } | |
632 | } | |
633 | } | |
ffa571da | 634 | |
1da177e4 LT |
635 | return 0; |
636 | } | |
637 | ||
651971cb | 638 | long do_msgsnd(int msqid, long mtype, void __user *mtext, |
639 | size_t msgsz, int msgflg) | |
1da177e4 LT |
640 | { |
641 | struct msg_queue *msq; | |
642 | struct msg_msg *msg; | |
1da177e4 | 643 | int err; |
1e786937 | 644 | struct ipc_namespace *ns; |
194a6b5b | 645 | DEFINE_WAKE_Q(wake_q); |
1e786937 KK |
646 | |
647 | ns = current->nsproxy->ipc_ns; | |
5a06a363 | 648 | |
1e786937 | 649 | if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0) |
1da177e4 | 650 | return -EINVAL; |
1da177e4 LT |
651 | if (mtype < 1) |
652 | return -EINVAL; | |
653 | ||
651971cb | 654 | msg = load_msg(mtext, msgsz); |
5a06a363 | 655 | if (IS_ERR(msg)) |
1da177e4 LT |
656 | return PTR_ERR(msg); |
657 | ||
658 | msg->m_type = mtype; | |
659 | msg->m_ts = msgsz; | |
660 | ||
3dd1f784 DB |
661 | rcu_read_lock(); |
662 | msq = msq_obtain_object_check(ns, msqid); | |
023a5355 ND |
663 | if (IS_ERR(msq)) { |
664 | err = PTR_ERR(msq); | |
3dd1f784 | 665 | goto out_unlock1; |
023a5355 | 666 | } |
1da177e4 | 667 | |
bebcb928 MS |
668 | ipc_lock_object(&msq->q_perm); |
669 | ||
1da177e4 LT |
670 | for (;;) { |
671 | struct msg_sender s; | |
672 | ||
5a06a363 | 673 | err = -EACCES; |
b0e77598 | 674 | if (ipcperms(ns, &msq->q_perm, S_IWUGO)) |
bebcb928 | 675 | goto out_unlock0; |
1da177e4 | 676 | |
4271b05a | 677 | /* raced with RMID? */ |
0f3d2b01 | 678 | if (!ipc_valid_object(&msq->q_perm)) { |
4271b05a DB |
679 | err = -EIDRM; |
680 | goto out_unlock0; | |
681 | } | |
682 | ||
1da177e4 LT |
683 | err = security_msg_queue_msgsnd(msq, msg, msgflg); |
684 | if (err) | |
bebcb928 | 685 | goto out_unlock0; |
1da177e4 | 686 | |
ed27f912 | 687 | if (msg_fits_inqueue(msq, msgsz)) |
1da177e4 | 688 | break; |
1da177e4 LT |
689 | |
690 | /* queue full, wait: */ | |
5a06a363 IM |
691 | if (msgflg & IPC_NOWAIT) { |
692 | err = -EAGAIN; | |
bebcb928 | 693 | goto out_unlock0; |
1da177e4 | 694 | } |
3dd1f784 | 695 | |
ffa571da | 696 | /* enqueue the sender and prepare to block */ |
ed27f912 | 697 | ss_add(msq, &s, msgsz); |
6062a8dc | 698 | |
dba4cdd3 | 699 | if (!ipc_rcu_getref(&msq->q_perm)) { |
6062a8dc | 700 | err = -EIDRM; |
3dd1f784 | 701 | goto out_unlock0; |
6062a8dc RR |
702 | } |
703 | ||
3dd1f784 DB |
704 | ipc_unlock_object(&msq->q_perm); |
705 | rcu_read_unlock(); | |
1da177e4 LT |
706 | schedule(); |
707 | ||
3dd1f784 DB |
708 | rcu_read_lock(); |
709 | ipc_lock_object(&msq->q_perm); | |
710 | ||
dba4cdd3 | 711 | ipc_rcu_putref(&msq->q_perm, msg_rcu_free); |
0f3d2b01 RA |
712 | /* raced with RMID? */ |
713 | if (!ipc_valid_object(&msq->q_perm)) { | |
1da177e4 | 714 | err = -EIDRM; |
3dd1f784 | 715 | goto out_unlock0; |
1da177e4 LT |
716 | } |
717 | ss_del(&s); | |
5a06a363 | 718 | |
1da177e4 | 719 | if (signal_pending(current)) { |
5a06a363 | 720 | err = -ERESTARTNOHAND; |
3dd1f784 | 721 | goto out_unlock0; |
1da177e4 | 722 | } |
3dd1f784 | 723 | |
1da177e4 | 724 | } |
ed27f912 | 725 | |
b488893a | 726 | msq->q_lspid = task_tgid_vnr(current); |
1da177e4 LT |
727 | msq->q_stime = get_seconds(); |
728 | ||
ee51636c | 729 | if (!pipelined_send(msq, msg, &wake_q)) { |
25985edc | 730 | /* no one is waiting for this message, enqueue it */ |
5a06a363 | 731 | list_add_tail(&msg->m_list, &msq->q_messages); |
1da177e4 LT |
732 | msq->q_cbytes += msgsz; |
733 | msq->q_qnum++; | |
3ac88a41 KK |
734 | atomic_add(msgsz, &ns->msg_bytes); |
735 | atomic_inc(&ns->msg_hdrs); | |
1da177e4 | 736 | } |
5a06a363 | 737 | |
1da177e4 LT |
738 | err = 0; |
739 | msg = NULL; | |
740 | ||
3dd1f784 DB |
741 | out_unlock0: |
742 | ipc_unlock_object(&msq->q_perm); | |
ee51636c | 743 | wake_up_q(&wake_q); |
3dd1f784 DB |
744 | out_unlock1: |
745 | rcu_read_unlock(); | |
5a06a363 | 746 | if (msg != NULL) |
1da177e4 LT |
747 | free_msg(msg); |
748 | return err; | |
749 | } | |
750 | ||
e48fbb69 HC |
751 | SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, |
752 | int, msgflg) | |
651971cb | 753 | { |
754 | long mtype; | |
755 | ||
756 | if (get_user(mtype, &msgp->mtype)) | |
757 | return -EFAULT; | |
758 | return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg); | |
759 | } | |
760 | ||
5a06a363 | 761 | static inline int convert_mode(long *msgtyp, int msgflg) |
1da177e4 | 762 | { |
8ac6ed58 PH |
763 | if (msgflg & MSG_COPY) |
764 | return SEARCH_NUMBER; | |
5a06a363 | 765 | /* |
1da177e4 LT |
766 | * find message of correct type. |
767 | * msgtyp = 0 => get first. | |
768 | * msgtyp > 0 => get first message of matching type. | |
5a06a363 | 769 | * msgtyp < 0 => get message with least type must be < abs(msgtype). |
1da177e4 | 770 | */ |
5a06a363 | 771 | if (*msgtyp == 0) |
1da177e4 | 772 | return SEARCH_ANY; |
5a06a363 | 773 | if (*msgtyp < 0) { |
99989835 JS |
774 | if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */ |
775 | *msgtyp = LONG_MAX; | |
776 | else | |
777 | *msgtyp = -*msgtyp; | |
1da177e4 LT |
778 | return SEARCH_LESSEQUAL; |
779 | } | |
5a06a363 | 780 | if (msgflg & MSG_EXCEPT) |
1da177e4 LT |
781 | return SEARCH_NOTEQUAL; |
782 | return SEARCH_EQUAL; | |
783 | } | |
784 | ||
f9dd87f4 SK |
785 | static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) |
786 | { | |
787 | struct msgbuf __user *msgp = dest; | |
788 | size_t msgsz; | |
789 | ||
790 | if (put_user(msg->m_type, &msgp->mtype)) | |
791 | return -EFAULT; | |
792 | ||
793 | msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; | |
794 | if (store_msg(msgp->mtext, msg, msgsz)) | |
795 | return -EFAULT; | |
796 | return msgsz; | |
797 | } | |
798 | ||
4a674f34 | 799 | #ifdef CONFIG_CHECKPOINT_RESTORE |
3fcfe786 SK |
800 | /* |
801 | * This function creates new kernel message structure, large enough to store | |
802 | * bufsz message bytes. | |
803 | */ | |
8ac6ed58 | 804 | static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) |
4a674f34 SK |
805 | { |
806 | struct msg_msg *copy; | |
807 | ||
4a674f34 SK |
808 | /* |
809 | * Create dummy message to copy real message to. | |
810 | */ | |
811 | copy = load_msg(buf, bufsz); | |
812 | if (!IS_ERR(copy)) | |
813 | copy->m_ts = bufsz; | |
814 | return copy; | |
815 | } | |
816 | ||
85398aa8 | 817 | static inline void free_copy(struct msg_msg *copy) |
4a674f34 | 818 | { |
85398aa8 | 819 | if (copy) |
4a674f34 SK |
820 | free_msg(copy); |
821 | } | |
822 | #else | |
8ac6ed58 | 823 | static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) |
b30efe27 SK |
824 | { |
825 | return ERR_PTR(-ENOSYS); | |
826 | } | |
827 | ||
85398aa8 SK |
828 | static inline void free_copy(struct msg_msg *copy) |
829 | { | |
830 | } | |
4a674f34 SK |
831 | #endif |
832 | ||
daaf74cf PH |
833 | static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode) |
834 | { | |
368ae537 | 835 | struct msg_msg *msg, *found = NULL; |
daaf74cf PH |
836 | long count = 0; |
837 | ||
838 | list_for_each_entry(msg, &msq->q_messages, m_list) { | |
839 | if (testmsg(msg, *msgtyp, mode) && | |
840 | !security_msg_queue_msgrcv(msq, msg, current, | |
841 | *msgtyp, mode)) { | |
842 | if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) { | |
843 | *msgtyp = msg->m_type - 1; | |
368ae537 | 844 | found = msg; |
daaf74cf PH |
845 | } else if (mode == SEARCH_NUMBER) { |
846 | if (*msgtyp == count) | |
847 | return msg; | |
848 | } else | |
849 | return msg; | |
850 | count++; | |
851 | } | |
852 | } | |
853 | ||
368ae537 | 854 | return found ?: ERR_PTR(-EAGAIN); |
daaf74cf PH |
855 | } |
856 | ||
41a0d523 | 857 | long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg, |
f9dd87f4 | 858 | long (*msg_handler)(void __user *, struct msg_msg *, size_t)) |
1da177e4 | 859 | { |
1da177e4 | 860 | int mode; |
41a0d523 | 861 | struct msg_queue *msq; |
1e786937 | 862 | struct ipc_namespace *ns; |
41a0d523 | 863 | struct msg_msg *msg, *copy = NULL; |
194a6b5b | 864 | DEFINE_WAKE_Q(wake_q); |
1da177e4 | 865 | |
88b9e456 PH |
866 | ns = current->nsproxy->ipc_ns; |
867 | ||
f9dd87f4 | 868 | if (msqid < 0 || (long) bufsz < 0) |
1da177e4 | 869 | return -EINVAL; |
41a0d523 | 870 | |
4a674f34 | 871 | if (msgflg & MSG_COPY) { |
4f87dac3 MK |
872 | if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT)) |
873 | return -EINVAL; | |
8ac6ed58 | 874 | copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); |
4a674f34 SK |
875 | if (IS_ERR(copy)) |
876 | return PTR_ERR(copy); | |
877 | } | |
5a06a363 | 878 | mode = convert_mode(&msgtyp, msgflg); |
1da177e4 | 879 | |
41a0d523 DB |
880 | rcu_read_lock(); |
881 | msq = msq_obtain_object_check(ns, msqid); | |
4a674f34 | 882 | if (IS_ERR(msq)) { |
41a0d523 | 883 | rcu_read_unlock(); |
85398aa8 | 884 | free_copy(copy); |
023a5355 | 885 | return PTR_ERR(msq); |
4a674f34 | 886 | } |
1da177e4 LT |
887 | |
888 | for (;;) { | |
889 | struct msg_receiver msr_d; | |
1da177e4 LT |
890 | |
891 | msg = ERR_PTR(-EACCES); | |
b0e77598 | 892 | if (ipcperms(ns, &msq->q_perm, S_IRUGO)) |
41a0d523 | 893 | goto out_unlock1; |
1da177e4 | 894 | |
41a0d523 | 895 | ipc_lock_object(&msq->q_perm); |
4271b05a DB |
896 | |
897 | /* raced with RMID? */ | |
0f3d2b01 | 898 | if (!ipc_valid_object(&msq->q_perm)) { |
4271b05a DB |
899 | msg = ERR_PTR(-EIDRM); |
900 | goto out_unlock0; | |
901 | } | |
902 | ||
daaf74cf | 903 | msg = find_msg(msq, &msgtyp, mode); |
5a06a363 IM |
904 | if (!IS_ERR(msg)) { |
905 | /* | |
906 | * Found a suitable message. | |
907 | * Unlink it from the queue. | |
908 | */ | |
f9dd87f4 | 909 | if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { |
1da177e4 | 910 | msg = ERR_PTR(-E2BIG); |
41a0d523 | 911 | goto out_unlock0; |
1da177e4 | 912 | } |
3fcfe786 SK |
913 | /* |
914 | * If we are copying, then do not unlink message and do | |
915 | * not update queue parameters. | |
916 | */ | |
852028af PH |
917 | if (msgflg & MSG_COPY) { |
918 | msg = copy_msg(msg, copy); | |
41a0d523 | 919 | goto out_unlock0; |
852028af | 920 | } |
41a0d523 | 921 | |
1da177e4 LT |
922 | list_del(&msg->m_list); |
923 | msq->q_qnum--; | |
924 | msq->q_rtime = get_seconds(); | |
b488893a | 925 | msq->q_lrpid = task_tgid_vnr(current); |
1da177e4 | 926 | msq->q_cbytes -= msg->m_ts; |
3ac88a41 KK |
927 | atomic_sub(msg->m_ts, &ns->msg_bytes); |
928 | atomic_dec(&ns->msg_hdrs); | |
ed27f912 | 929 | ss_wakeup(msq, &wake_q, false); |
41a0d523 DB |
930 | |
931 | goto out_unlock0; | |
1da177e4 | 932 | } |
41a0d523 | 933 | |
1da177e4 LT |
934 | /* No message waiting. Wait for a message */ |
935 | if (msgflg & IPC_NOWAIT) { | |
936 | msg = ERR_PTR(-ENOMSG); | |
41a0d523 | 937 | goto out_unlock0; |
1da177e4 | 938 | } |
41a0d523 | 939 | |
5a06a363 | 940 | list_add_tail(&msr_d.r_list, &msq->q_receivers); |
1da177e4 LT |
941 | msr_d.r_tsk = current; |
942 | msr_d.r_msgtype = msgtyp; | |
943 | msr_d.r_mode = mode; | |
5a06a363 | 944 | if (msgflg & MSG_NOERROR) |
1da177e4 | 945 | msr_d.r_maxsize = INT_MAX; |
5a06a363 | 946 | else |
f9dd87f4 | 947 | msr_d.r_maxsize = bufsz; |
1da177e4 | 948 | msr_d.r_msg = ERR_PTR(-EAGAIN); |
f75a2f35 | 949 | __set_current_state(TASK_INTERRUPTIBLE); |
1da177e4 | 950 | |
41a0d523 DB |
951 | ipc_unlock_object(&msq->q_perm); |
952 | rcu_read_unlock(); | |
1da177e4 LT |
953 | schedule(); |
954 | ||
ee51636c SAS |
955 | /* |
956 | * Lockless receive, part 1: | |
957 | * We don't hold a reference to the queue and getting a | |
958 | * reference would defeat the idea of a lockless operation, | |
959 | * thus the code relies on rcu to guarantee the existence of | |
960 | * msq: | |
1da177e4 LT |
961 | * Prior to destruction, expunge_all(-EIRDM) changes r_msg. |
962 | * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. | |
1da177e4 LT |
963 | */ |
964 | rcu_read_lock(); | |
965 | ||
ee51636c SAS |
966 | /* |
967 | * Lockless receive, part 2: | |
968 | * The work in pipelined_send() and expunge_all(): | |
969 | * - Set pointer to message | |
970 | * - Queue the receiver task for later wakeup | |
971 | * - Wake up the process after the lock is dropped. | |
ff35e5ef | 972 | * |
ee51636c SAS |
973 | * Should the process wake up before this wakeup (due to a |
974 | * signal) it will either see the message and continue ... | |
1da177e4 | 975 | */ |
ee51636c | 976 | msg = READ_ONCE(msr_d.r_msg); |
41a0d523 DB |
977 | if (msg != ERR_PTR(-EAGAIN)) |
978 | goto out_unlock1; | |
1da177e4 | 979 | |
ee51636c SAS |
980 | /* |
981 | * ... or see -EAGAIN, acquire the lock to check the message | |
982 | * again. | |
983 | */ | |
41a0d523 | 984 | ipc_lock_object(&msq->q_perm); |
1da177e4 | 985 | |
ee51636c | 986 | msg = msr_d.r_msg; |
5a06a363 | 987 | if (msg != ERR_PTR(-EAGAIN)) |
41a0d523 | 988 | goto out_unlock0; |
1da177e4 LT |
989 | |
990 | list_del(&msr_d.r_list); | |
991 | if (signal_pending(current)) { | |
992 | msg = ERR_PTR(-ERESTARTNOHAND); | |
41a0d523 | 993 | goto out_unlock0; |
1da177e4 | 994 | } |
41a0d523 DB |
995 | |
996 | ipc_unlock_object(&msq->q_perm); | |
1da177e4 | 997 | } |
41a0d523 DB |
998 | |
999 | out_unlock0: | |
1000 | ipc_unlock_object(&msq->q_perm); | |
e3658538 | 1001 | wake_up_q(&wake_q); |
41a0d523 DB |
1002 | out_unlock1: |
1003 | rcu_read_unlock(); | |
4a674f34 | 1004 | if (IS_ERR(msg)) { |
85398aa8 | 1005 | free_copy(copy); |
5a06a363 | 1006 | return PTR_ERR(msg); |
4a674f34 | 1007 | } |
1da177e4 | 1008 | |
f9dd87f4 | 1009 | bufsz = msg_handler(buf, msg, bufsz); |
1da177e4 | 1010 | free_msg(msg); |
5a06a363 | 1011 | |
f9dd87f4 | 1012 | return bufsz; |
1da177e4 LT |
1013 | } |
1014 | ||
e48fbb69 HC |
1015 | SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, |
1016 | long, msgtyp, int, msgflg) | |
651971cb | 1017 | { |
f9dd87f4 | 1018 | return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill); |
651971cb | 1019 | } |
1020 | ||
3440a6bd DB |
1021 | |
1022 | void msg_init_ns(struct ipc_namespace *ns) | |
1023 | { | |
1024 | ns->msg_ctlmax = MSGMAX; | |
1025 | ns->msg_ctlmnb = MSGMNB; | |
0050ee05 | 1026 | ns->msg_ctlmni = MSGMNI; |
3440a6bd DB |
1027 | |
1028 | atomic_set(&ns->msg_bytes, 0); | |
1029 | atomic_set(&ns->msg_hdrs, 0); | |
1030 | ipc_init_ids(&ns->ids[IPC_MSG_IDS]); | |
1031 | } | |
1032 | ||
1033 | #ifdef CONFIG_IPC_NS | |
1034 | void msg_exit_ns(struct ipc_namespace *ns) | |
1035 | { | |
1036 | free_ipcs(ns, &msg_ids(ns), freeque); | |
1037 | idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr); | |
1038 | } | |
1039 | #endif | |
1040 | ||
1da177e4 | 1041 | #ifdef CONFIG_PROC_FS |
19b4946c | 1042 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it) |
1da177e4 | 1043 | { |
1efdb69b | 1044 | struct user_namespace *user_ns = seq_user_ns(s); |
19b4946c MW |
1045 | struct msg_queue *msq = it; |
1046 | ||
7f032d6e JP |
1047 | seq_printf(s, |
1048 | "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n", | |
1049 | msq->q_perm.key, | |
1050 | msq->q_perm.id, | |
1051 | msq->q_perm.mode, | |
1052 | msq->q_cbytes, | |
1053 | msq->q_qnum, | |
1054 | msq->q_lspid, | |
1055 | msq->q_lrpid, | |
1056 | from_kuid_munged(user_ns, msq->q_perm.uid), | |
1057 | from_kgid_munged(user_ns, msq->q_perm.gid), | |
1058 | from_kuid_munged(user_ns, msq->q_perm.cuid), | |
1059 | from_kgid_munged(user_ns, msq->q_perm.cgid), | |
1060 | msq->q_stime, | |
1061 | msq->q_rtime, | |
1062 | msq->q_ctime); | |
1063 | ||
1064 | return 0; | |
1da177e4 LT |
1065 | } |
1066 | #endif | |
3440a6bd DB |
1067 | |
1068 | void __init msg_init(void) | |
1069 | { | |
1070 | msg_init_ns(&init_ipc_ns); | |
1071 | ||
3440a6bd DB |
1072 | ipc_init_proc_interface("sysvipc/msg", |
1073 | " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", | |
1074 | IPC_MSG_IDS, sysvipc_msg_proc_show); | |
1075 | } |