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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> | |
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 | 48 | struct 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 */ | |
60 | struct 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 | |
01b8b07a | 73 | static void freeque(struct ipc_namespace *, struct kern_ipc_perm *); |
7748dbfa | 74 | static int newque(struct ipc_namespace *, struct ipc_params *); |
1da177e4 | 75 | #ifdef CONFIG_PROC_FS |
19b4946c | 76 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it); |
1da177e4 LT |
77 | #endif |
78 | ||
f7bf3df8 ND |
79 | /* |
80 | * Scale msgmni with the available lowmem size: the memory dedicated to msg | |
81 | * queues should occupy at most 1/MSG_MEM_SCALE of lowmem. | |
4d89dc6a ND |
82 | * Also take into account the number of nsproxies created so far. |
83 | * This should be done staying within the (MSGMNI , IPCMNI/nr_ipc_ns) range. | |
f7bf3df8 | 84 | */ |
b6b337ad | 85 | void recompute_msgmni(struct ipc_namespace *ns) |
f7bf3df8 ND |
86 | { |
87 | struct sysinfo i; | |
88 | unsigned long allowed; | |
4d89dc6a | 89 | int nb_ns; |
f7bf3df8 ND |
90 | |
91 | si_meminfo(&i); | |
92 | allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit) | |
93 | / MSGMNB; | |
4d89dc6a ND |
94 | nb_ns = atomic_read(&nr_ipc_ns); |
95 | allowed /= nb_ns; | |
f7bf3df8 ND |
96 | |
97 | if (allowed < MSGMNI) { | |
98 | ns->msg_ctlmni = MSGMNI; | |
dfcceb26 | 99 | return; |
f7bf3df8 ND |
100 | } |
101 | ||
4d89dc6a ND |
102 | if (allowed > IPCMNI / nb_ns) { |
103 | ns->msg_ctlmni = IPCMNI / nb_ns; | |
dfcceb26 | 104 | return; |
f7bf3df8 ND |
105 | } |
106 | ||
107 | ns->msg_ctlmni = allowed; | |
f7bf3df8 ND |
108 | } |
109 | ||
ed2ddbf8 | 110 | void msg_init_ns(struct ipc_namespace *ns) |
1e786937 | 111 | { |
1e786937 KK |
112 | ns->msg_ctlmax = MSGMAX; |
113 | ns->msg_ctlmnb = MSGMNB; | |
f7bf3df8 ND |
114 | |
115 | recompute_msgmni(ns); | |
116 | ||
3ac88a41 KK |
117 | atomic_set(&ns->msg_bytes, 0); |
118 | atomic_set(&ns->msg_hdrs, 0); | |
ed2ddbf8 | 119 | ipc_init_ids(&ns->ids[IPC_MSG_IDS]); |
1e786937 KK |
120 | } |
121 | ||
ae5e1b22 | 122 | #ifdef CONFIG_IPC_NS |
1e786937 KK |
123 | void msg_exit_ns(struct ipc_namespace *ns) |
124 | { | |
01b8b07a | 125 | free_ipcs(ns, &msg_ids(ns), freeque); |
7d6feeb2 | 126 | idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr); |
1e786937 | 127 | } |
ae5e1b22 | 128 | #endif |
1e786937 | 129 | |
5a06a363 | 130 | void __init msg_init(void) |
1da177e4 | 131 | { |
ed2ddbf8 | 132 | msg_init_ns(&init_ipc_ns); |
dfcceb26 ND |
133 | |
134 | printk(KERN_INFO "msgmni has been set to %d\n", | |
135 | init_ipc_ns.msg_ctlmni); | |
136 | ||
19b4946c MW |
137 | ipc_init_proc_interface("sysvipc/msg", |
138 | " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", | |
1e786937 | 139 | IPC_MSG_IDS, sysvipc_msg_proc_show); |
1da177e4 LT |
140 | } |
141 | ||
a5001a0d DB |
142 | static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id) |
143 | { | |
144 | struct kern_ipc_perm *ipcp = ipc_obtain_object(&msg_ids(ns), id); | |
145 | ||
146 | if (IS_ERR(ipcp)) | |
147 | return ERR_CAST(ipcp); | |
148 | ||
149 | return container_of(ipcp, struct msg_queue, q_perm); | |
150 | } | |
151 | ||
152 | static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns, | |
153 | int id) | |
154 | { | |
155 | struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id); | |
156 | ||
157 | if (IS_ERR(ipcp)) | |
158 | return ERR_CAST(ipcp); | |
159 | ||
160 | return container_of(ipcp, struct msg_queue, q_perm); | |
161 | } | |
162 | ||
7ca7e564 ND |
163 | static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s) |
164 | { | |
165 | ipc_rmid(&msg_ids(ns), &s->q_perm); | |
166 | } | |
167 | ||
f4566f04 ND |
168 | /** |
169 | * newque - Create a new msg queue | |
170 | * @ns: namespace | |
171 | * @params: ptr to the structure that contains the key and msgflg | |
172 | * | |
d9a605e4 | 173 | * Called with msg_ids.rwsem held (writer) |
f4566f04 | 174 | */ |
7748dbfa | 175 | static int newque(struct ipc_namespace *ns, struct ipc_params *params) |
1da177e4 | 176 | { |
1da177e4 | 177 | struct msg_queue *msq; |
5a06a363 | 178 | int id, retval; |
7748dbfa ND |
179 | key_t key = params->key; |
180 | int msgflg = params->flg; | |
1da177e4 | 181 | |
5a06a363 IM |
182 | msq = ipc_rcu_alloc(sizeof(*msq)); |
183 | if (!msq) | |
1da177e4 LT |
184 | return -ENOMEM; |
185 | ||
5a06a363 | 186 | msq->q_perm.mode = msgflg & S_IRWXUGO; |
1da177e4 LT |
187 | msq->q_perm.key = key; |
188 | ||
189 | msq->q_perm.security = NULL; | |
190 | retval = security_msg_queue_alloc(msq); | |
191 | if (retval) { | |
192 | ipc_rcu_putref(msq); | |
193 | return retval; | |
194 | } | |
195 | ||
dbfcd91f | 196 | /* ipc_addid() locks msq upon success. */ |
1e786937 | 197 | id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); |
283bb7fa | 198 | if (id < 0) { |
1da177e4 LT |
199 | security_msg_queue_free(msq); |
200 | ipc_rcu_putref(msq); | |
283bb7fa | 201 | return id; |
1da177e4 LT |
202 | } |
203 | ||
204 | msq->q_stime = msq->q_rtime = 0; | |
205 | msq->q_ctime = get_seconds(); | |
206 | msq->q_cbytes = msq->q_qnum = 0; | |
1e786937 | 207 | msq->q_qbytes = ns->msg_ctlmnb; |
1da177e4 LT |
208 | msq->q_lspid = msq->q_lrpid = 0; |
209 | INIT_LIST_HEAD(&msq->q_messages); | |
210 | INIT_LIST_HEAD(&msq->q_receivers); | |
211 | INIT_LIST_HEAD(&msq->q_senders); | |
7ca7e564 | 212 | |
cf9d5d78 | 213 | ipc_unlock_object(&msq->q_perm); |
dbfcd91f | 214 | rcu_read_unlock(); |
1da177e4 | 215 | |
7ca7e564 | 216 | return msq->q_perm.id; |
1da177e4 LT |
217 | } |
218 | ||
5a06a363 | 219 | static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss) |
1da177e4 | 220 | { |
5a06a363 IM |
221 | mss->tsk = current; |
222 | current->state = TASK_INTERRUPTIBLE; | |
223 | list_add_tail(&mss->list, &msq->q_senders); | |
1da177e4 LT |
224 | } |
225 | ||
5a06a363 | 226 | static inline void ss_del(struct msg_sender *mss) |
1da177e4 | 227 | { |
5a06a363 | 228 | if (mss->list.next != NULL) |
1da177e4 LT |
229 | list_del(&mss->list); |
230 | } | |
231 | ||
5a06a363 | 232 | static void ss_wakeup(struct list_head *h, int kill) |
1da177e4 | 233 | { |
41239fe8 | 234 | struct msg_sender *mss, *t; |
1da177e4 | 235 | |
41239fe8 | 236 | list_for_each_entry_safe(mss, t, h, list) { |
5a06a363 IM |
237 | if (kill) |
238 | mss->list.next = NULL; | |
1da177e4 LT |
239 | wake_up_process(mss->tsk); |
240 | } | |
241 | } | |
242 | ||
5a06a363 | 243 | static void expunge_all(struct msg_queue *msq, int res) |
1da177e4 | 244 | { |
41239fe8 | 245 | struct msg_receiver *msr, *t; |
5a06a363 | 246 | |
41239fe8 | 247 | list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { |
1da177e4 LT |
248 | msr->r_msg = NULL; |
249 | wake_up_process(msr->r_tsk); | |
250 | smp_mb(); | |
251 | msr->r_msg = ERR_PTR(res); | |
252 | } | |
253 | } | |
5a06a363 IM |
254 | |
255 | /* | |
256 | * freeque() wakes up waiters on the sender and receiver waiting queue, | |
f4566f04 ND |
257 | * removes the message queue from message queue ID IDR, and cleans up all the |
258 | * messages associated with this queue. | |
1da177e4 | 259 | * |
d9a605e4 DB |
260 | * msg_ids.rwsem (writer) and the spinlock for this message queue are held |
261 | * before freeque() is called. msg_ids.rwsem remains locked on exit. | |
1da177e4 | 262 | */ |
01b8b07a | 263 | static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) |
1da177e4 | 264 | { |
41239fe8 | 265 | struct msg_msg *msg, *t; |
01b8b07a | 266 | struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); |
1da177e4 | 267 | |
5a06a363 IM |
268 | expunge_all(msq, -EIDRM); |
269 | ss_wakeup(&msq->q_senders, 1); | |
7ca7e564 | 270 | msg_rmid(ns, msq); |
4718787d DB |
271 | ipc_unlock_object(&msq->q_perm); |
272 | rcu_read_unlock(); | |
5a06a363 | 273 | |
41239fe8 | 274 | list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) { |
3ac88a41 | 275 | atomic_dec(&ns->msg_hdrs); |
1da177e4 LT |
276 | free_msg(msg); |
277 | } | |
3ac88a41 | 278 | atomic_sub(msq->q_cbytes, &ns->msg_bytes); |
1da177e4 LT |
279 | security_msg_queue_free(msq); |
280 | ipc_rcu_putref(msq); | |
281 | } | |
282 | ||
f4566f04 | 283 | /* |
d9a605e4 | 284 | * Called with msg_ids.rwsem and ipcp locked. |
f4566f04 | 285 | */ |
03f02c76 | 286 | static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg) |
7748dbfa | 287 | { |
03f02c76 ND |
288 | struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); |
289 | ||
290 | return security_msg_queue_associate(msq, msgflg); | |
7748dbfa ND |
291 | } |
292 | ||
e48fbb69 | 293 | SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg) |
1da177e4 | 294 | { |
1e786937 | 295 | struct ipc_namespace *ns; |
7748dbfa ND |
296 | struct ipc_ops msg_ops; |
297 | struct ipc_params msg_params; | |
1e786937 KK |
298 | |
299 | ns = current->nsproxy->ipc_ns; | |
7ca7e564 | 300 | |
7748dbfa ND |
301 | msg_ops.getnew = newque; |
302 | msg_ops.associate = msg_security; | |
303 | msg_ops.more_checks = NULL; | |
304 | ||
305 | msg_params.key = key; | |
306 | msg_params.flg = msgflg; | |
5a06a363 | 307 | |
7748dbfa | 308 | return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params); |
1da177e4 LT |
309 | } |
310 | ||
5a06a363 IM |
311 | static inline unsigned long |
312 | copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) | |
1da177e4 LT |
313 | { |
314 | switch(version) { | |
315 | case IPC_64: | |
5a06a363 | 316 | return copy_to_user(buf, in, sizeof(*in)); |
1da177e4 | 317 | case IPC_OLD: |
5a06a363 | 318 | { |
1da177e4 LT |
319 | struct msqid_ds out; |
320 | ||
5a06a363 | 321 | memset(&out, 0, sizeof(out)); |
1da177e4 LT |
322 | |
323 | ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); | |
324 | ||
325 | out.msg_stime = in->msg_stime; | |
326 | out.msg_rtime = in->msg_rtime; | |
327 | out.msg_ctime = in->msg_ctime; | |
328 | ||
4be929be AD |
329 | if (in->msg_cbytes > USHRT_MAX) |
330 | out.msg_cbytes = USHRT_MAX; | |
1da177e4 LT |
331 | else |
332 | out.msg_cbytes = in->msg_cbytes; | |
333 | out.msg_lcbytes = in->msg_cbytes; | |
334 | ||
4be929be AD |
335 | if (in->msg_qnum > USHRT_MAX) |
336 | out.msg_qnum = USHRT_MAX; | |
1da177e4 LT |
337 | else |
338 | out.msg_qnum = in->msg_qnum; | |
339 | ||
4be929be AD |
340 | if (in->msg_qbytes > USHRT_MAX) |
341 | out.msg_qbytes = USHRT_MAX; | |
1da177e4 LT |
342 | else |
343 | out.msg_qbytes = in->msg_qbytes; | |
344 | out.msg_lqbytes = in->msg_qbytes; | |
345 | ||
346 | out.msg_lspid = in->msg_lspid; | |
347 | out.msg_lrpid = in->msg_lrpid; | |
348 | ||
5a06a363 IM |
349 | return copy_to_user(buf, &out, sizeof(out)); |
350 | } | |
1da177e4 LT |
351 | default: |
352 | return -EINVAL; | |
353 | } | |
354 | } | |
355 | ||
5a06a363 | 356 | static inline unsigned long |
016d7132 | 357 | copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version) |
1da177e4 LT |
358 | { |
359 | switch(version) { | |
360 | case IPC_64: | |
016d7132 | 361 | if (copy_from_user(out, buf, sizeof(*out))) |
1da177e4 | 362 | return -EFAULT; |
1da177e4 | 363 | return 0; |
1da177e4 | 364 | case IPC_OLD: |
5a06a363 | 365 | { |
1da177e4 LT |
366 | struct msqid_ds tbuf_old; |
367 | ||
5a06a363 | 368 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) |
1da177e4 LT |
369 | return -EFAULT; |
370 | ||
016d7132 PP |
371 | out->msg_perm.uid = tbuf_old.msg_perm.uid; |
372 | out->msg_perm.gid = tbuf_old.msg_perm.gid; | |
373 | out->msg_perm.mode = tbuf_old.msg_perm.mode; | |
1da177e4 | 374 | |
5a06a363 | 375 | if (tbuf_old.msg_qbytes == 0) |
016d7132 | 376 | out->msg_qbytes = tbuf_old.msg_lqbytes; |
1da177e4 | 377 | else |
016d7132 | 378 | out->msg_qbytes = tbuf_old.msg_qbytes; |
1da177e4 LT |
379 | |
380 | return 0; | |
5a06a363 | 381 | } |
1da177e4 LT |
382 | default: |
383 | return -EINVAL; | |
384 | } | |
385 | } | |
386 | ||
a0d092fc | 387 | /* |
d9a605e4 | 388 | * This function handles some msgctl commands which require the rwsem |
a0d092fc | 389 | * to be held in write mode. |
d9a605e4 | 390 | * NOTE: no locks must be held, the rwsem is taken inside this function. |
a0d092fc PP |
391 | */ |
392 | static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, | |
393 | struct msqid_ds __user *buf, int version) | |
1da177e4 | 394 | { |
1da177e4 | 395 | struct kern_ipc_perm *ipcp; |
f1970c48 | 396 | struct msqid64_ds uninitialized_var(msqid64); |
a0d092fc PP |
397 | struct msg_queue *msq; |
398 | int err; | |
399 | ||
400 | if (cmd == IPC_SET) { | |
016d7132 | 401 | if (copy_msqid_from_user(&msqid64, buf, version)) |
a0d092fc PP |
402 | return -EFAULT; |
403 | } | |
404 | ||
d9a605e4 | 405 | down_write(&msg_ids(ns).rwsem); |
7b4cc5d8 DB |
406 | rcu_read_lock(); |
407 | ||
15724ecb DB |
408 | ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd, |
409 | &msqid64.msg_perm, msqid64.msg_qbytes); | |
7b4cc5d8 DB |
410 | if (IS_ERR(ipcp)) { |
411 | err = PTR_ERR(ipcp); | |
7b4cc5d8 DB |
412 | goto out_unlock1; |
413 | } | |
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) | |
15724ecb | 419 | goto out_unlock1; |
a0d092fc PP |
420 | |
421 | switch (cmd) { | |
422 | case IPC_RMID: | |
15724ecb | 423 | ipc_lock_object(&msq->q_perm); |
7b4cc5d8 | 424 | /* freeque unlocks the ipc object and rcu */ |
a0d092fc PP |
425 | freeque(ns, ipcp); |
426 | goto out_up; | |
427 | case IPC_SET: | |
016d7132 | 428 | if (msqid64.msg_qbytes > ns->msg_ctlmnb && |
a0d092fc PP |
429 | !capable(CAP_SYS_RESOURCE)) { |
430 | err = -EPERM; | |
15724ecb | 431 | goto out_unlock1; |
a0d092fc PP |
432 | } |
433 | ||
15724ecb | 434 | ipc_lock_object(&msq->q_perm); |
1efdb69b EB |
435 | err = ipc_update_perm(&msqid64.msg_perm, ipcp); |
436 | if (err) | |
7b4cc5d8 | 437 | goto out_unlock0; |
1efdb69b | 438 | |
016d7132 | 439 | msq->q_qbytes = msqid64.msg_qbytes; |
a0d092fc | 440 | |
a0d092fc PP |
441 | msq->q_ctime = get_seconds(); |
442 | /* sleeping receivers might be excluded by | |
443 | * stricter permissions. | |
444 | */ | |
445 | expunge_all(msq, -EAGAIN); | |
446 | /* sleeping senders might be able to send | |
447 | * due to a larger queue size. | |
448 | */ | |
449 | ss_wakeup(&msq->q_senders, 0); | |
450 | break; | |
451 | default: | |
452 | err = -EINVAL; | |
15724ecb | 453 | goto out_unlock1; |
a0d092fc | 454 | } |
7b4cc5d8 DB |
455 | |
456 | out_unlock0: | |
457 | ipc_unlock_object(&msq->q_perm); | |
458 | out_unlock1: | |
459 | rcu_read_unlock(); | |
a0d092fc | 460 | out_up: |
d9a605e4 | 461 | up_write(&msg_ids(ns).rwsem); |
a0d092fc PP |
462 | return err; |
463 | } | |
464 | ||
2cafed30 DB |
465 | static int msgctl_nolock(struct ipc_namespace *ns, int msqid, |
466 | int cmd, int version, void __user *buf) | |
a0d092fc | 467 | { |
2cafed30 | 468 | int err; |
5a06a363 | 469 | struct msg_queue *msq; |
1da177e4 LT |
470 | |
471 | switch (cmd) { | |
5a06a363 IM |
472 | case IPC_INFO: |
473 | case MSG_INFO: | |
474 | { | |
1da177e4 LT |
475 | struct msginfo msginfo; |
476 | int max_id; | |
5a06a363 | 477 | |
1da177e4 LT |
478 | if (!buf) |
479 | return -EFAULT; | |
2cafed30 | 480 | |
5a06a363 IM |
481 | /* |
482 | * We must not return kernel stack data. | |
1da177e4 LT |
483 | * due to padding, it's not enough |
484 | * to set all member fields. | |
485 | */ | |
1da177e4 LT |
486 | err = security_msg_queue_msgctl(NULL, cmd); |
487 | if (err) | |
488 | return err; | |
489 | ||
5a06a363 | 490 | memset(&msginfo, 0, sizeof(msginfo)); |
1e786937 KK |
491 | msginfo.msgmni = ns->msg_ctlmni; |
492 | msginfo.msgmax = ns->msg_ctlmax; | |
493 | msginfo.msgmnb = ns->msg_ctlmnb; | |
1da177e4 LT |
494 | msginfo.msgssz = MSGSSZ; |
495 | msginfo.msgseg = MSGSEG; | |
d9a605e4 | 496 | down_read(&msg_ids(ns).rwsem); |
1da177e4 | 497 | if (cmd == MSG_INFO) { |
1e786937 | 498 | msginfo.msgpool = msg_ids(ns).in_use; |
3ac88a41 KK |
499 | msginfo.msgmap = atomic_read(&ns->msg_hdrs); |
500 | msginfo.msgtql = atomic_read(&ns->msg_bytes); | |
1da177e4 LT |
501 | } else { |
502 | msginfo.msgmap = MSGMAP; | |
503 | msginfo.msgpool = MSGPOOL; | |
504 | msginfo.msgtql = MSGTQL; | |
505 | } | |
7ca7e564 | 506 | max_id = ipc_get_maxid(&msg_ids(ns)); |
d9a605e4 | 507 | up_read(&msg_ids(ns).rwsem); |
5a06a363 | 508 | if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) |
1da177e4 | 509 | return -EFAULT; |
5a06a363 | 510 | return (max_id < 0) ? 0 : max_id; |
1da177e4 | 511 | } |
2cafed30 DB |
512 | |
513 | case MSG_STAT: | |
1da177e4 LT |
514 | case IPC_STAT: |
515 | { | |
516 | struct msqid64_ds tbuf; | |
517 | int success_return; | |
5a06a363 | 518 | |
1da177e4 LT |
519 | if (!buf) |
520 | return -EFAULT; | |
1da177e4 | 521 | |
ac0ba20e DB |
522 | memset(&tbuf, 0, sizeof(tbuf)); |
523 | ||
524 | rcu_read_lock(); | |
5a06a363 | 525 | if (cmd == MSG_STAT) { |
ac0ba20e DB |
526 | msq = msq_obtain_object(ns, msqid); |
527 | if (IS_ERR(msq)) { | |
528 | err = PTR_ERR(msq); | |
529 | goto out_unlock; | |
530 | } | |
7ca7e564 | 531 | success_return = msq->q_perm.id; |
1da177e4 | 532 | } else { |
ac0ba20e DB |
533 | msq = msq_obtain_object_check(ns, msqid); |
534 | if (IS_ERR(msq)) { | |
535 | err = PTR_ERR(msq); | |
536 | goto out_unlock; | |
537 | } | |
1da177e4 LT |
538 | success_return = 0; |
539 | } | |
ac0ba20e | 540 | |
1da177e4 | 541 | err = -EACCES; |
b0e77598 | 542 | if (ipcperms(ns, &msq->q_perm, S_IRUGO)) |
1da177e4 LT |
543 | goto out_unlock; |
544 | ||
545 | err = security_msg_queue_msgctl(msq, cmd); | |
546 | if (err) | |
547 | goto out_unlock; | |
548 | ||
549 | kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm); | |
550 | tbuf.msg_stime = msq->q_stime; | |
551 | tbuf.msg_rtime = msq->q_rtime; | |
552 | tbuf.msg_ctime = msq->q_ctime; | |
553 | tbuf.msg_cbytes = msq->q_cbytes; | |
554 | tbuf.msg_qnum = msq->q_qnum; | |
555 | tbuf.msg_qbytes = msq->q_qbytes; | |
556 | tbuf.msg_lspid = msq->q_lspid; | |
557 | tbuf.msg_lrpid = msq->q_lrpid; | |
ac0ba20e DB |
558 | rcu_read_unlock(); |
559 | ||
1da177e4 LT |
560 | if (copy_msqid_to_user(buf, &tbuf, version)) |
561 | return -EFAULT; | |
562 | return success_return; | |
563 | } | |
2cafed30 | 564 | |
1da177e4 | 565 | default: |
2cafed30 | 566 | return -EINVAL; |
1da177e4 LT |
567 | } |
568 | ||
2cafed30 | 569 | return err; |
1da177e4 | 570 | out_unlock: |
ac0ba20e | 571 | rcu_read_unlock(); |
1da177e4 LT |
572 | return err; |
573 | } | |
574 | ||
2cafed30 DB |
575 | SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) |
576 | { | |
577 | int version; | |
578 | struct ipc_namespace *ns; | |
579 | ||
580 | if (msqid < 0 || cmd < 0) | |
581 | return -EINVAL; | |
582 | ||
583 | version = ipc_parse_version(&cmd); | |
584 | ns = current->nsproxy->ipc_ns; | |
585 | ||
586 | switch (cmd) { | |
587 | case IPC_INFO: | |
588 | case MSG_INFO: | |
589 | case MSG_STAT: /* msqid is an index rather than a msg queue id */ | |
590 | case IPC_STAT: | |
591 | return msgctl_nolock(ns, msqid, cmd, version, buf); | |
592 | case IPC_SET: | |
593 | case IPC_RMID: | |
594 | return msgctl_down(ns, msqid, cmd, buf, version); | |
595 | default: | |
596 | return -EINVAL; | |
597 | } | |
598 | } | |
599 | ||
5a06a363 | 600 | static int testmsg(struct msg_msg *msg, long type, int mode) |
1da177e4 LT |
601 | { |
602 | switch(mode) | |
603 | { | |
604 | case SEARCH_ANY: | |
8ac6ed58 | 605 | case SEARCH_NUMBER: |
1da177e4 LT |
606 | return 1; |
607 | case SEARCH_LESSEQUAL: | |
5a06a363 | 608 | if (msg->m_type <=type) |
1da177e4 LT |
609 | return 1; |
610 | break; | |
611 | case SEARCH_EQUAL: | |
5a06a363 | 612 | if (msg->m_type == type) |
1da177e4 LT |
613 | return 1; |
614 | break; | |
615 | case SEARCH_NOTEQUAL: | |
5a06a363 | 616 | if (msg->m_type != type) |
1da177e4 LT |
617 | return 1; |
618 | break; | |
619 | } | |
620 | return 0; | |
621 | } | |
622 | ||
5a06a363 | 623 | static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg) |
1da177e4 | 624 | { |
41239fe8 | 625 | struct msg_receiver *msr, *t; |
5a06a363 | 626 | |
41239fe8 | 627 | list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { |
5a06a363 IM |
628 | if (testmsg(msg, msr->r_msgtype, msr->r_mode) && |
629 | !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, | |
630 | msr->r_msgtype, msr->r_mode)) { | |
631 | ||
1da177e4 | 632 | list_del(&msr->r_list); |
5a06a363 | 633 | if (msr->r_maxsize < msg->m_ts) { |
1da177e4 LT |
634 | msr->r_msg = NULL; |
635 | wake_up_process(msr->r_tsk); | |
636 | smp_mb(); | |
637 | msr->r_msg = ERR_PTR(-E2BIG); | |
638 | } else { | |
639 | msr->r_msg = NULL; | |
b488893a | 640 | msq->q_lrpid = task_pid_vnr(msr->r_tsk); |
1da177e4 LT |
641 | msq->q_rtime = get_seconds(); |
642 | wake_up_process(msr->r_tsk); | |
643 | smp_mb(); | |
644 | msr->r_msg = msg; | |
5a06a363 | 645 | |
1da177e4 LT |
646 | return 1; |
647 | } | |
648 | } | |
649 | } | |
650 | return 0; | |
651 | } | |
652 | ||
651971cb | 653 | long do_msgsnd(int msqid, long mtype, void __user *mtext, |
654 | size_t msgsz, int msgflg) | |
1da177e4 LT |
655 | { |
656 | struct msg_queue *msq; | |
657 | struct msg_msg *msg; | |
1da177e4 | 658 | int err; |
1e786937 KK |
659 | struct ipc_namespace *ns; |
660 | ||
661 | ns = current->nsproxy->ipc_ns; | |
5a06a363 | 662 | |
1e786937 | 663 | if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0) |
1da177e4 | 664 | return -EINVAL; |
1da177e4 LT |
665 | if (mtype < 1) |
666 | return -EINVAL; | |
667 | ||
651971cb | 668 | msg = load_msg(mtext, msgsz); |
5a06a363 | 669 | if (IS_ERR(msg)) |
1da177e4 LT |
670 | return PTR_ERR(msg); |
671 | ||
672 | msg->m_type = mtype; | |
673 | msg->m_ts = msgsz; | |
674 | ||
3dd1f784 DB |
675 | rcu_read_lock(); |
676 | msq = msq_obtain_object_check(ns, msqid); | |
023a5355 ND |
677 | if (IS_ERR(msq)) { |
678 | err = PTR_ERR(msq); | |
3dd1f784 | 679 | goto out_unlock1; |
023a5355 | 680 | } |
1da177e4 | 681 | |
bebcb928 MS |
682 | ipc_lock_object(&msq->q_perm); |
683 | ||
1da177e4 LT |
684 | for (;;) { |
685 | struct msg_sender s; | |
686 | ||
5a06a363 | 687 | err = -EACCES; |
b0e77598 | 688 | if (ipcperms(ns, &msq->q_perm, S_IWUGO)) |
bebcb928 | 689 | goto out_unlock0; |
1da177e4 LT |
690 | |
691 | err = security_msg_queue_msgsnd(msq, msg, msgflg); | |
692 | if (err) | |
bebcb928 | 693 | goto out_unlock0; |
1da177e4 | 694 | |
5a06a363 | 695 | if (msgsz + msq->q_cbytes <= msq->q_qbytes && |
1da177e4 LT |
696 | 1 + msq->q_qnum <= msq->q_qbytes) { |
697 | break; | |
698 | } | |
699 | ||
700 | /* queue full, wait: */ | |
5a06a363 IM |
701 | if (msgflg & IPC_NOWAIT) { |
702 | err = -EAGAIN; | |
bebcb928 | 703 | goto out_unlock0; |
1da177e4 | 704 | } |
3dd1f784 | 705 | |
1da177e4 | 706 | ss_add(msq, &s); |
6062a8dc RR |
707 | |
708 | if (!ipc_rcu_getref(msq)) { | |
709 | err = -EIDRM; | |
3dd1f784 | 710 | goto out_unlock0; |
6062a8dc RR |
711 | } |
712 | ||
3dd1f784 DB |
713 | ipc_unlock_object(&msq->q_perm); |
714 | rcu_read_unlock(); | |
1da177e4 LT |
715 | schedule(); |
716 | ||
3dd1f784 DB |
717 | rcu_read_lock(); |
718 | ipc_lock_object(&msq->q_perm); | |
719 | ||
1da177e4 LT |
720 | ipc_rcu_putref(msq); |
721 | if (msq->q_perm.deleted) { | |
722 | err = -EIDRM; | |
3dd1f784 | 723 | goto out_unlock0; |
1da177e4 | 724 | } |
3dd1f784 | 725 | |
1da177e4 | 726 | ss_del(&s); |
5a06a363 | 727 | |
1da177e4 | 728 | if (signal_pending(current)) { |
5a06a363 | 729 | err = -ERESTARTNOHAND; |
3dd1f784 | 730 | goto out_unlock0; |
1da177e4 | 731 | } |
3dd1f784 | 732 | |
1da177e4 | 733 | } |
b488893a | 734 | msq->q_lspid = task_tgid_vnr(current); |
1da177e4 LT |
735 | msq->q_stime = get_seconds(); |
736 | ||
5a06a363 | 737 | if (!pipelined_send(msq, msg)) { |
25985edc | 738 | /* no one is waiting for this message, enqueue it */ |
5a06a363 | 739 | list_add_tail(&msg->m_list, &msq->q_messages); |
1da177e4 LT |
740 | msq->q_cbytes += msgsz; |
741 | msq->q_qnum++; | |
3ac88a41 KK |
742 | atomic_add(msgsz, &ns->msg_bytes); |
743 | atomic_inc(&ns->msg_hdrs); | |
1da177e4 | 744 | } |
5a06a363 | 745 | |
1da177e4 LT |
746 | err = 0; |
747 | msg = NULL; | |
748 | ||
3dd1f784 DB |
749 | out_unlock0: |
750 | ipc_unlock_object(&msq->q_perm); | |
751 | out_unlock1: | |
752 | rcu_read_unlock(); | |
5a06a363 | 753 | if (msg != NULL) |
1da177e4 LT |
754 | free_msg(msg); |
755 | return err; | |
756 | } | |
757 | ||
e48fbb69 HC |
758 | SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, |
759 | int, msgflg) | |
651971cb | 760 | { |
761 | long mtype; | |
762 | ||
763 | if (get_user(mtype, &msgp->mtype)) | |
764 | return -EFAULT; | |
765 | return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg); | |
766 | } | |
767 | ||
5a06a363 | 768 | static inline int convert_mode(long *msgtyp, int msgflg) |
1da177e4 | 769 | { |
8ac6ed58 PH |
770 | if (msgflg & MSG_COPY) |
771 | return SEARCH_NUMBER; | |
5a06a363 | 772 | /* |
1da177e4 LT |
773 | * find message of correct type. |
774 | * msgtyp = 0 => get first. | |
775 | * msgtyp > 0 => get first message of matching type. | |
5a06a363 | 776 | * msgtyp < 0 => get message with least type must be < abs(msgtype). |
1da177e4 | 777 | */ |
5a06a363 | 778 | if (*msgtyp == 0) |
1da177e4 | 779 | return SEARCH_ANY; |
5a06a363 IM |
780 | if (*msgtyp < 0) { |
781 | *msgtyp = -*msgtyp; | |
1da177e4 LT |
782 | return SEARCH_LESSEQUAL; |
783 | } | |
5a06a363 | 784 | if (msgflg & MSG_EXCEPT) |
1da177e4 LT |
785 | return SEARCH_NOTEQUAL; |
786 | return SEARCH_EQUAL; | |
787 | } | |
788 | ||
f9dd87f4 SK |
789 | static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) |
790 | { | |
791 | struct msgbuf __user *msgp = dest; | |
792 | size_t msgsz; | |
793 | ||
794 | if (put_user(msg->m_type, &msgp->mtype)) | |
795 | return -EFAULT; | |
796 | ||
797 | msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; | |
798 | if (store_msg(msgp->mtext, msg, msgsz)) | |
799 | return -EFAULT; | |
800 | return msgsz; | |
801 | } | |
802 | ||
4a674f34 | 803 | #ifdef CONFIG_CHECKPOINT_RESTORE |
3fcfe786 SK |
804 | /* |
805 | * This function creates new kernel message structure, large enough to store | |
806 | * bufsz message bytes. | |
807 | */ | |
8ac6ed58 | 808 | static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) |
4a674f34 SK |
809 | { |
810 | struct msg_msg *copy; | |
811 | ||
4a674f34 SK |
812 | /* |
813 | * Create dummy message to copy real message to. | |
814 | */ | |
815 | copy = load_msg(buf, bufsz); | |
816 | if (!IS_ERR(copy)) | |
817 | copy->m_ts = bufsz; | |
818 | return copy; | |
819 | } | |
820 | ||
85398aa8 | 821 | static inline void free_copy(struct msg_msg *copy) |
4a674f34 | 822 | { |
85398aa8 | 823 | if (copy) |
4a674f34 SK |
824 | free_msg(copy); |
825 | } | |
826 | #else | |
8ac6ed58 | 827 | static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) |
b30efe27 SK |
828 | { |
829 | return ERR_PTR(-ENOSYS); | |
830 | } | |
831 | ||
85398aa8 SK |
832 | static inline void free_copy(struct msg_msg *copy) |
833 | { | |
834 | } | |
4a674f34 SK |
835 | #endif |
836 | ||
daaf74cf PH |
837 | static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode) |
838 | { | |
368ae537 | 839 | struct msg_msg *msg, *found = NULL; |
daaf74cf PH |
840 | long count = 0; |
841 | ||
842 | list_for_each_entry(msg, &msq->q_messages, m_list) { | |
843 | if (testmsg(msg, *msgtyp, mode) && | |
844 | !security_msg_queue_msgrcv(msq, msg, current, | |
845 | *msgtyp, mode)) { | |
846 | if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) { | |
847 | *msgtyp = msg->m_type - 1; | |
368ae537 | 848 | found = msg; |
daaf74cf PH |
849 | } else if (mode == SEARCH_NUMBER) { |
850 | if (*msgtyp == count) | |
851 | return msg; | |
852 | } else | |
853 | return msg; | |
854 | count++; | |
855 | } | |
856 | } | |
857 | ||
368ae537 | 858 | return found ?: ERR_PTR(-EAGAIN); |
daaf74cf PH |
859 | } |
860 | ||
41a0d523 | 861 | long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg, |
f9dd87f4 | 862 | long (*msg_handler)(void __user *, struct msg_msg *, size_t)) |
1da177e4 | 863 | { |
1da177e4 | 864 | int mode; |
41a0d523 | 865 | struct msg_queue *msq; |
1e786937 | 866 | struct ipc_namespace *ns; |
41a0d523 | 867 | struct msg_msg *msg, *copy = NULL; |
1da177e4 | 868 | |
88b9e456 PH |
869 | ns = current->nsproxy->ipc_ns; |
870 | ||
f9dd87f4 | 871 | if (msqid < 0 || (long) bufsz < 0) |
1da177e4 | 872 | return -EINVAL; |
41a0d523 | 873 | |
4a674f34 | 874 | if (msgflg & MSG_COPY) { |
8ac6ed58 | 875 | copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); |
4a674f34 SK |
876 | if (IS_ERR(copy)) |
877 | return PTR_ERR(copy); | |
878 | } | |
5a06a363 | 879 | mode = convert_mode(&msgtyp, msgflg); |
1da177e4 | 880 | |
41a0d523 DB |
881 | rcu_read_lock(); |
882 | msq = msq_obtain_object_check(ns, msqid); | |
4a674f34 | 883 | if (IS_ERR(msq)) { |
41a0d523 | 884 | rcu_read_unlock(); |
85398aa8 | 885 | free_copy(copy); |
023a5355 | 886 | return PTR_ERR(msq); |
4a674f34 | 887 | } |
1da177e4 LT |
888 | |
889 | for (;;) { | |
890 | struct msg_receiver msr_d; | |
1da177e4 LT |
891 | |
892 | msg = ERR_PTR(-EACCES); | |
b0e77598 | 893 | if (ipcperms(ns, &msq->q_perm, S_IRUGO)) |
41a0d523 | 894 | goto out_unlock1; |
1da177e4 | 895 | |
41a0d523 | 896 | ipc_lock_object(&msq->q_perm); |
daaf74cf | 897 | msg = find_msg(msq, &msgtyp, mode); |
5a06a363 IM |
898 | if (!IS_ERR(msg)) { |
899 | /* | |
900 | * Found a suitable message. | |
901 | * Unlink it from the queue. | |
902 | */ | |
f9dd87f4 | 903 | if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { |
1da177e4 | 904 | msg = ERR_PTR(-E2BIG); |
41a0d523 | 905 | goto out_unlock0; |
1da177e4 | 906 | } |
3fcfe786 SK |
907 | /* |
908 | * If we are copying, then do not unlink message and do | |
909 | * not update queue parameters. | |
910 | */ | |
852028af PH |
911 | if (msgflg & MSG_COPY) { |
912 | msg = copy_msg(msg, copy); | |
41a0d523 | 913 | goto out_unlock0; |
852028af | 914 | } |
41a0d523 | 915 | |
1da177e4 LT |
916 | list_del(&msg->m_list); |
917 | msq->q_qnum--; | |
918 | msq->q_rtime = get_seconds(); | |
b488893a | 919 | msq->q_lrpid = task_tgid_vnr(current); |
1da177e4 | 920 | msq->q_cbytes -= msg->m_ts; |
3ac88a41 KK |
921 | atomic_sub(msg->m_ts, &ns->msg_bytes); |
922 | atomic_dec(&ns->msg_hdrs); | |
5a06a363 | 923 | ss_wakeup(&msq->q_senders, 0); |
41a0d523 DB |
924 | |
925 | goto out_unlock0; | |
1da177e4 | 926 | } |
41a0d523 | 927 | |
1da177e4 LT |
928 | /* No message waiting. Wait for a message */ |
929 | if (msgflg & IPC_NOWAIT) { | |
930 | msg = ERR_PTR(-ENOMSG); | |
41a0d523 | 931 | goto out_unlock0; |
1da177e4 | 932 | } |
41a0d523 | 933 | |
5a06a363 | 934 | list_add_tail(&msr_d.r_list, &msq->q_receivers); |
1da177e4 LT |
935 | msr_d.r_tsk = current; |
936 | msr_d.r_msgtype = msgtyp; | |
937 | msr_d.r_mode = mode; | |
5a06a363 | 938 | if (msgflg & MSG_NOERROR) |
1da177e4 | 939 | msr_d.r_maxsize = INT_MAX; |
5a06a363 | 940 | else |
f9dd87f4 | 941 | msr_d.r_maxsize = bufsz; |
1da177e4 LT |
942 | msr_d.r_msg = ERR_PTR(-EAGAIN); |
943 | current->state = TASK_INTERRUPTIBLE; | |
1da177e4 | 944 | |
41a0d523 DB |
945 | ipc_unlock_object(&msq->q_perm); |
946 | rcu_read_unlock(); | |
1da177e4 LT |
947 | schedule(); |
948 | ||
949 | /* Lockless receive, part 1: | |
950 | * Disable preemption. We don't hold a reference to the queue | |
951 | * and getting a reference would defeat the idea of a lockless | |
952 | * operation, thus the code relies on rcu to guarantee the | |
25985edc | 953 | * existence of msq: |
1da177e4 LT |
954 | * Prior to destruction, expunge_all(-EIRDM) changes r_msg. |
955 | * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. | |
956 | * rcu_read_lock() prevents preemption between reading r_msg | |
41a0d523 | 957 | * and acquiring the q_perm.lock in ipc_lock_object(). |
1da177e4 LT |
958 | */ |
959 | rcu_read_lock(); | |
960 | ||
961 | /* Lockless receive, part 2: | |
962 | * Wait until pipelined_send or expunge_all are outside of | |
963 | * wake_up_process(). There is a race with exit(), see | |
964 | * ipc/mqueue.c for the details. | |
965 | */ | |
5a06a363 | 966 | msg = (struct msg_msg*)msr_d.r_msg; |
1da177e4 LT |
967 | while (msg == NULL) { |
968 | cpu_relax(); | |
5a06a363 | 969 | msg = (struct msg_msg *)msr_d.r_msg; |
1da177e4 LT |
970 | } |
971 | ||
972 | /* Lockless receive, part 3: | |
973 | * If there is a message or an error then accept it without | |
974 | * locking. | |
975 | */ | |
41a0d523 DB |
976 | if (msg != ERR_PTR(-EAGAIN)) |
977 | goto out_unlock1; | |
1da177e4 LT |
978 | |
979 | /* Lockless receive, part 3: | |
980 | * Acquire the queue spinlock. | |
981 | */ | |
41a0d523 | 982 | ipc_lock_object(&msq->q_perm); |
1da177e4 LT |
983 | |
984 | /* Lockless receive, part 4: | |
985 | * Repeat test after acquiring the spinlock. | |
986 | */ | |
987 | msg = (struct msg_msg*)msr_d.r_msg; | |
5a06a363 | 988 | if (msg != ERR_PTR(-EAGAIN)) |
41a0d523 | 989 | goto out_unlock0; |
1da177e4 LT |
990 | |
991 | list_del(&msr_d.r_list); | |
992 | if (signal_pending(current)) { | |
993 | msg = ERR_PTR(-ERESTARTNOHAND); | |
41a0d523 | 994 | goto out_unlock0; |
1da177e4 | 995 | } |
41a0d523 DB |
996 | |
997 | ipc_unlock_object(&msq->q_perm); | |
1da177e4 | 998 | } |
41a0d523 DB |
999 | |
1000 | out_unlock0: | |
1001 | ipc_unlock_object(&msq->q_perm); | |
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 | ||
1da177e4 | 1021 | #ifdef CONFIG_PROC_FS |
19b4946c | 1022 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it) |
1da177e4 | 1023 | { |
1efdb69b | 1024 | struct user_namespace *user_ns = seq_user_ns(s); |
19b4946c MW |
1025 | struct msg_queue *msq = it; |
1026 | ||
1027 | return seq_printf(s, | |
5a06a363 IM |
1028 | "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n", |
1029 | msq->q_perm.key, | |
7ca7e564 | 1030 | msq->q_perm.id, |
5a06a363 IM |
1031 | msq->q_perm.mode, |
1032 | msq->q_cbytes, | |
1033 | msq->q_qnum, | |
1034 | msq->q_lspid, | |
1035 | msq->q_lrpid, | |
1efdb69b EB |
1036 | from_kuid_munged(user_ns, msq->q_perm.uid), |
1037 | from_kgid_munged(user_ns, msq->q_perm.gid), | |
1038 | from_kuid_munged(user_ns, msq->q_perm.cuid), | |
1039 | from_kgid_munged(user_ns, msq->q_perm.cgid), | |
5a06a363 IM |
1040 | msq->q_stime, |
1041 | msq->q_rtime, | |
1042 | msq->q_ctime); | |
1da177e4 LT |
1043 | } |
1044 | #endif |