Commit | Line | Data |
---|---|---|
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 | |
1e786937 | 73 | #define msg_unlock(msq) ipc_unlock(&(msq)->q_perm) |
1e786937 | 74 | |
01b8b07a | 75 | static void freeque(struct ipc_namespace *, struct kern_ipc_perm *); |
7748dbfa | 76 | static int newque(struct ipc_namespace *, struct ipc_params *); |
1da177e4 | 77 | #ifdef CONFIG_PROC_FS |
19b4946c | 78 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it); |
1da177e4 LT |
79 | #endif |
80 | ||
f7bf3df8 ND |
81 | /* |
82 | * Scale msgmni with the available lowmem size: the memory dedicated to msg | |
83 | * queues should occupy at most 1/MSG_MEM_SCALE of lowmem. | |
4d89dc6a ND |
84 | * Also take into account the number of nsproxies created so far. |
85 | * This should be done staying within the (MSGMNI , IPCMNI/nr_ipc_ns) range. | |
f7bf3df8 | 86 | */ |
b6b337ad | 87 | void recompute_msgmni(struct ipc_namespace *ns) |
f7bf3df8 ND |
88 | { |
89 | struct sysinfo i; | |
90 | unsigned long allowed; | |
4d89dc6a | 91 | int nb_ns; |
f7bf3df8 ND |
92 | |
93 | si_meminfo(&i); | |
94 | allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit) | |
95 | / MSGMNB; | |
4d89dc6a ND |
96 | nb_ns = atomic_read(&nr_ipc_ns); |
97 | allowed /= nb_ns; | |
f7bf3df8 ND |
98 | |
99 | if (allowed < MSGMNI) { | |
100 | ns->msg_ctlmni = MSGMNI; | |
dfcceb26 | 101 | return; |
f7bf3df8 ND |
102 | } |
103 | ||
4d89dc6a ND |
104 | if (allowed > IPCMNI / nb_ns) { |
105 | ns->msg_ctlmni = IPCMNI / nb_ns; | |
dfcceb26 | 106 | return; |
f7bf3df8 ND |
107 | } |
108 | ||
109 | ns->msg_ctlmni = allowed; | |
f7bf3df8 ND |
110 | } |
111 | ||
ed2ddbf8 | 112 | void msg_init_ns(struct ipc_namespace *ns) |
1e786937 | 113 | { |
1e786937 KK |
114 | ns->msg_ctlmax = MSGMAX; |
115 | ns->msg_ctlmnb = MSGMNB; | |
f7bf3df8 ND |
116 | |
117 | recompute_msgmni(ns); | |
118 | ||
3ac88a41 KK |
119 | atomic_set(&ns->msg_bytes, 0); |
120 | atomic_set(&ns->msg_hdrs, 0); | |
ed2ddbf8 | 121 | ipc_init_ids(&ns->ids[IPC_MSG_IDS]); |
1e786937 KK |
122 | } |
123 | ||
ae5e1b22 | 124 | #ifdef CONFIG_IPC_NS |
1e786937 KK |
125 | void msg_exit_ns(struct ipc_namespace *ns) |
126 | { | |
01b8b07a | 127 | free_ipcs(ns, &msg_ids(ns), freeque); |
7d6feeb2 | 128 | idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr); |
1e786937 | 129 | } |
ae5e1b22 | 130 | #endif |
1e786937 | 131 | |
5a06a363 | 132 | void __init msg_init(void) |
1da177e4 | 133 | { |
ed2ddbf8 | 134 | msg_init_ns(&init_ipc_ns); |
dfcceb26 ND |
135 | |
136 | printk(KERN_INFO "msgmni has been set to %d\n", | |
137 | init_ipc_ns.msg_ctlmni); | |
138 | ||
19b4946c MW |
139 | ipc_init_proc_interface("sysvipc/msg", |
140 | " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", | |
1e786937 | 141 | IPC_MSG_IDS, sysvipc_msg_proc_show); |
1da177e4 LT |
142 | } |
143 | ||
3e148c79 ND |
144 | /* |
145 | * msg_lock_(check_) routines are called in the paths where the rw_mutex | |
146 | * is not held. | |
147 | */ | |
023a5355 ND |
148 | static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id) |
149 | { | |
03f02c76 ND |
150 | struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id); |
151 | ||
b1ed88b4 PP |
152 | if (IS_ERR(ipcp)) |
153 | return (struct msg_queue *)ipcp; | |
154 | ||
03f02c76 | 155 | return container_of(ipcp, struct msg_queue, q_perm); |
023a5355 ND |
156 | } |
157 | ||
158 | static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns, | |
159 | int id) | |
160 | { | |
03f02c76 ND |
161 | struct kern_ipc_perm *ipcp = ipc_lock_check(&msg_ids(ns), id); |
162 | ||
b1ed88b4 PP |
163 | if (IS_ERR(ipcp)) |
164 | return (struct msg_queue *)ipcp; | |
165 | ||
03f02c76 | 166 | return container_of(ipcp, struct msg_queue, q_perm); |
023a5355 ND |
167 | } |
168 | ||
a5001a0d DB |
169 | static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id) |
170 | { | |
171 | struct kern_ipc_perm *ipcp = ipc_obtain_object(&msg_ids(ns), id); | |
172 | ||
173 | if (IS_ERR(ipcp)) | |
174 | return ERR_CAST(ipcp); | |
175 | ||
176 | return container_of(ipcp, struct msg_queue, q_perm); | |
177 | } | |
178 | ||
179 | static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns, | |
180 | int id) | |
181 | { | |
182 | struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id); | |
183 | ||
184 | if (IS_ERR(ipcp)) | |
185 | return ERR_CAST(ipcp); | |
186 | ||
187 | return container_of(ipcp, struct msg_queue, q_perm); | |
188 | } | |
189 | ||
7ca7e564 ND |
190 | static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s) |
191 | { | |
192 | ipc_rmid(&msg_ids(ns), &s->q_perm); | |
193 | } | |
194 | ||
f4566f04 ND |
195 | /** |
196 | * newque - Create a new msg queue | |
197 | * @ns: namespace | |
198 | * @params: ptr to the structure that contains the key and msgflg | |
199 | * | |
3e148c79 | 200 | * Called with msg_ids.rw_mutex held (writer) |
f4566f04 | 201 | */ |
7748dbfa | 202 | static int newque(struct ipc_namespace *ns, struct ipc_params *params) |
1da177e4 | 203 | { |
1da177e4 | 204 | struct msg_queue *msq; |
5a06a363 | 205 | int id, retval; |
7748dbfa ND |
206 | key_t key = params->key; |
207 | int msgflg = params->flg; | |
1da177e4 | 208 | |
5a06a363 IM |
209 | msq = ipc_rcu_alloc(sizeof(*msq)); |
210 | if (!msq) | |
1da177e4 LT |
211 | return -ENOMEM; |
212 | ||
5a06a363 | 213 | msq->q_perm.mode = msgflg & S_IRWXUGO; |
1da177e4 LT |
214 | msq->q_perm.key = key; |
215 | ||
216 | msq->q_perm.security = NULL; | |
217 | retval = security_msg_queue_alloc(msq); | |
218 | if (retval) { | |
219 | ipc_rcu_putref(msq); | |
220 | return retval; | |
221 | } | |
222 | ||
dbfcd91f | 223 | /* ipc_addid() locks msq upon success. */ |
1e786937 | 224 | id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); |
283bb7fa | 225 | if (id < 0) { |
1da177e4 LT |
226 | security_msg_queue_free(msq); |
227 | ipc_rcu_putref(msq); | |
283bb7fa | 228 | return id; |
1da177e4 LT |
229 | } |
230 | ||
231 | msq->q_stime = msq->q_rtime = 0; | |
232 | msq->q_ctime = get_seconds(); | |
233 | msq->q_cbytes = msq->q_qnum = 0; | |
1e786937 | 234 | msq->q_qbytes = ns->msg_ctlmnb; |
1da177e4 LT |
235 | msq->q_lspid = msq->q_lrpid = 0; |
236 | INIT_LIST_HEAD(&msq->q_messages); | |
237 | INIT_LIST_HEAD(&msq->q_receivers); | |
238 | INIT_LIST_HEAD(&msq->q_senders); | |
7ca7e564 | 239 | |
cf9d5d78 | 240 | ipc_unlock_object(&msq->q_perm); |
dbfcd91f | 241 | rcu_read_unlock(); |
1da177e4 | 242 | |
7ca7e564 | 243 | return msq->q_perm.id; |
1da177e4 LT |
244 | } |
245 | ||
5a06a363 | 246 | static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss) |
1da177e4 | 247 | { |
5a06a363 IM |
248 | mss->tsk = current; |
249 | current->state = TASK_INTERRUPTIBLE; | |
250 | list_add_tail(&mss->list, &msq->q_senders); | |
1da177e4 LT |
251 | } |
252 | ||
5a06a363 | 253 | static inline void ss_del(struct msg_sender *mss) |
1da177e4 | 254 | { |
5a06a363 | 255 | if (mss->list.next != NULL) |
1da177e4 LT |
256 | list_del(&mss->list); |
257 | } | |
258 | ||
5a06a363 | 259 | static void ss_wakeup(struct list_head *h, int kill) |
1da177e4 | 260 | { |
41239fe8 | 261 | struct msg_sender *mss, *t; |
1da177e4 | 262 | |
41239fe8 | 263 | list_for_each_entry_safe(mss, t, h, list) { |
5a06a363 IM |
264 | if (kill) |
265 | mss->list.next = NULL; | |
1da177e4 LT |
266 | wake_up_process(mss->tsk); |
267 | } | |
268 | } | |
269 | ||
5a06a363 | 270 | static void expunge_all(struct msg_queue *msq, int res) |
1da177e4 | 271 | { |
41239fe8 | 272 | struct msg_receiver *msr, *t; |
5a06a363 | 273 | |
41239fe8 | 274 | list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { |
1da177e4 LT |
275 | msr->r_msg = NULL; |
276 | wake_up_process(msr->r_tsk); | |
277 | smp_mb(); | |
278 | msr->r_msg = ERR_PTR(res); | |
279 | } | |
280 | } | |
5a06a363 IM |
281 | |
282 | /* | |
283 | * freeque() wakes up waiters on the sender and receiver waiting queue, | |
f4566f04 ND |
284 | * removes the message queue from message queue ID IDR, and cleans up all the |
285 | * messages associated with this queue. | |
1da177e4 | 286 | * |
3e148c79 ND |
287 | * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held |
288 | * before freeque() is called. msg_ids.rw_mutex remains locked on exit. | |
1da177e4 | 289 | */ |
01b8b07a | 290 | static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) |
1da177e4 | 291 | { |
41239fe8 | 292 | struct msg_msg *msg, *t; |
01b8b07a | 293 | struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); |
1da177e4 | 294 | |
5a06a363 IM |
295 | expunge_all(msq, -EIDRM); |
296 | ss_wakeup(&msq->q_senders, 1); | |
7ca7e564 | 297 | msg_rmid(ns, msq); |
1da177e4 | 298 | msg_unlock(msq); |
5a06a363 | 299 | |
41239fe8 | 300 | list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) { |
3ac88a41 | 301 | atomic_dec(&ns->msg_hdrs); |
1da177e4 LT |
302 | free_msg(msg); |
303 | } | |
3ac88a41 | 304 | atomic_sub(msq->q_cbytes, &ns->msg_bytes); |
1da177e4 LT |
305 | security_msg_queue_free(msq); |
306 | ipc_rcu_putref(msq); | |
307 | } | |
308 | ||
f4566f04 | 309 | /* |
3e148c79 | 310 | * Called with msg_ids.rw_mutex and ipcp locked. |
f4566f04 | 311 | */ |
03f02c76 | 312 | static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg) |
7748dbfa | 313 | { |
03f02c76 ND |
314 | struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); |
315 | ||
316 | return security_msg_queue_associate(msq, msgflg); | |
7748dbfa ND |
317 | } |
318 | ||
e48fbb69 | 319 | SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg) |
1da177e4 | 320 | { |
1e786937 | 321 | struct ipc_namespace *ns; |
7748dbfa ND |
322 | struct ipc_ops msg_ops; |
323 | struct ipc_params msg_params; | |
1e786937 KK |
324 | |
325 | ns = current->nsproxy->ipc_ns; | |
7ca7e564 | 326 | |
7748dbfa ND |
327 | msg_ops.getnew = newque; |
328 | msg_ops.associate = msg_security; | |
329 | msg_ops.more_checks = NULL; | |
330 | ||
331 | msg_params.key = key; | |
332 | msg_params.flg = msgflg; | |
5a06a363 | 333 | |
7748dbfa | 334 | return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params); |
1da177e4 LT |
335 | } |
336 | ||
5a06a363 IM |
337 | static inline unsigned long |
338 | copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) | |
1da177e4 LT |
339 | { |
340 | switch(version) { | |
341 | case IPC_64: | |
5a06a363 | 342 | return copy_to_user(buf, in, sizeof(*in)); |
1da177e4 | 343 | case IPC_OLD: |
5a06a363 | 344 | { |
1da177e4 LT |
345 | struct msqid_ds out; |
346 | ||
5a06a363 | 347 | memset(&out, 0, sizeof(out)); |
1da177e4 LT |
348 | |
349 | ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); | |
350 | ||
351 | out.msg_stime = in->msg_stime; | |
352 | out.msg_rtime = in->msg_rtime; | |
353 | out.msg_ctime = in->msg_ctime; | |
354 | ||
4be929be AD |
355 | if (in->msg_cbytes > USHRT_MAX) |
356 | out.msg_cbytes = USHRT_MAX; | |
1da177e4 LT |
357 | else |
358 | out.msg_cbytes = in->msg_cbytes; | |
359 | out.msg_lcbytes = in->msg_cbytes; | |
360 | ||
4be929be AD |
361 | if (in->msg_qnum > USHRT_MAX) |
362 | out.msg_qnum = USHRT_MAX; | |
1da177e4 LT |
363 | else |
364 | out.msg_qnum = in->msg_qnum; | |
365 | ||
4be929be AD |
366 | if (in->msg_qbytes > USHRT_MAX) |
367 | out.msg_qbytes = USHRT_MAX; | |
1da177e4 LT |
368 | else |
369 | out.msg_qbytes = in->msg_qbytes; | |
370 | out.msg_lqbytes = in->msg_qbytes; | |
371 | ||
372 | out.msg_lspid = in->msg_lspid; | |
373 | out.msg_lrpid = in->msg_lrpid; | |
374 | ||
5a06a363 IM |
375 | return copy_to_user(buf, &out, sizeof(out)); |
376 | } | |
1da177e4 LT |
377 | default: |
378 | return -EINVAL; | |
379 | } | |
380 | } | |
381 | ||
5a06a363 | 382 | static inline unsigned long |
016d7132 | 383 | copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version) |
1da177e4 LT |
384 | { |
385 | switch(version) { | |
386 | case IPC_64: | |
016d7132 | 387 | if (copy_from_user(out, buf, sizeof(*out))) |
1da177e4 | 388 | return -EFAULT; |
1da177e4 | 389 | return 0; |
1da177e4 | 390 | case IPC_OLD: |
5a06a363 | 391 | { |
1da177e4 LT |
392 | struct msqid_ds tbuf_old; |
393 | ||
5a06a363 | 394 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) |
1da177e4 LT |
395 | return -EFAULT; |
396 | ||
016d7132 PP |
397 | out->msg_perm.uid = tbuf_old.msg_perm.uid; |
398 | out->msg_perm.gid = tbuf_old.msg_perm.gid; | |
399 | out->msg_perm.mode = tbuf_old.msg_perm.mode; | |
1da177e4 | 400 | |
5a06a363 | 401 | if (tbuf_old.msg_qbytes == 0) |
016d7132 | 402 | out->msg_qbytes = tbuf_old.msg_lqbytes; |
1da177e4 | 403 | else |
016d7132 | 404 | out->msg_qbytes = tbuf_old.msg_qbytes; |
1da177e4 LT |
405 | |
406 | return 0; | |
5a06a363 | 407 | } |
1da177e4 LT |
408 | default: |
409 | return -EINVAL; | |
410 | } | |
411 | } | |
412 | ||
a0d092fc PP |
413 | /* |
414 | * This function handles some msgctl commands which require the rw_mutex | |
415 | * to be held in write mode. | |
416 | * NOTE: no locks must be held, the rw_mutex is taken inside this function. | |
417 | */ | |
418 | static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, | |
419 | struct msqid_ds __user *buf, int version) | |
1da177e4 | 420 | { |
1da177e4 | 421 | struct kern_ipc_perm *ipcp; |
f1970c48 | 422 | struct msqid64_ds uninitialized_var(msqid64); |
a0d092fc PP |
423 | struct msg_queue *msq; |
424 | int err; | |
425 | ||
426 | if (cmd == IPC_SET) { | |
016d7132 | 427 | if (copy_msqid_from_user(&msqid64, buf, version)) |
a0d092fc PP |
428 | return -EFAULT; |
429 | } | |
430 | ||
7b4cc5d8 DB |
431 | down_write(&msg_ids(ns).rw_mutex); |
432 | rcu_read_lock(); | |
433 | ||
15724ecb DB |
434 | ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd, |
435 | &msqid64.msg_perm, msqid64.msg_qbytes); | |
7b4cc5d8 DB |
436 | if (IS_ERR(ipcp)) { |
437 | err = PTR_ERR(ipcp); | |
7b4cc5d8 DB |
438 | goto out_unlock1; |
439 | } | |
a0d092fc | 440 | |
a5f75e7f | 441 | msq = container_of(ipcp, struct msg_queue, q_perm); |
a0d092fc PP |
442 | |
443 | err = security_msg_queue_msgctl(msq, cmd); | |
444 | if (err) | |
15724ecb | 445 | goto out_unlock1; |
a0d092fc PP |
446 | |
447 | switch (cmd) { | |
448 | case IPC_RMID: | |
15724ecb | 449 | ipc_lock_object(&msq->q_perm); |
7b4cc5d8 | 450 | /* freeque unlocks the ipc object and rcu */ |
a0d092fc PP |
451 | freeque(ns, ipcp); |
452 | goto out_up; | |
453 | case IPC_SET: | |
016d7132 | 454 | if (msqid64.msg_qbytes > ns->msg_ctlmnb && |
a0d092fc PP |
455 | !capable(CAP_SYS_RESOURCE)) { |
456 | err = -EPERM; | |
15724ecb | 457 | goto out_unlock1; |
a0d092fc PP |
458 | } |
459 | ||
15724ecb | 460 | ipc_lock_object(&msq->q_perm); |
1efdb69b EB |
461 | err = ipc_update_perm(&msqid64.msg_perm, ipcp); |
462 | if (err) | |
7b4cc5d8 | 463 | goto out_unlock0; |
1efdb69b | 464 | |
016d7132 | 465 | msq->q_qbytes = msqid64.msg_qbytes; |
a0d092fc | 466 | |
a0d092fc PP |
467 | msq->q_ctime = get_seconds(); |
468 | /* sleeping receivers might be excluded by | |
469 | * stricter permissions. | |
470 | */ | |
471 | expunge_all(msq, -EAGAIN); | |
472 | /* sleeping senders might be able to send | |
473 | * due to a larger queue size. | |
474 | */ | |
475 | ss_wakeup(&msq->q_senders, 0); | |
476 | break; | |
477 | default: | |
478 | err = -EINVAL; | |
15724ecb | 479 | goto out_unlock1; |
a0d092fc | 480 | } |
7b4cc5d8 DB |
481 | |
482 | out_unlock0: | |
483 | ipc_unlock_object(&msq->q_perm); | |
484 | out_unlock1: | |
485 | rcu_read_unlock(); | |
a0d092fc PP |
486 | out_up: |
487 | up_write(&msg_ids(ns).rw_mutex); | |
488 | return err; | |
489 | } | |
490 | ||
2cafed30 DB |
491 | static int msgctl_nolock(struct ipc_namespace *ns, int msqid, |
492 | int cmd, int version, void __user *buf) | |
a0d092fc | 493 | { |
2cafed30 | 494 | int err; |
5a06a363 | 495 | struct msg_queue *msq; |
1da177e4 LT |
496 | |
497 | switch (cmd) { | |
5a06a363 IM |
498 | case IPC_INFO: |
499 | case MSG_INFO: | |
500 | { | |
1da177e4 LT |
501 | struct msginfo msginfo; |
502 | int max_id; | |
5a06a363 | 503 | |
1da177e4 LT |
504 | if (!buf) |
505 | return -EFAULT; | |
2cafed30 | 506 | |
5a06a363 IM |
507 | /* |
508 | * We must not return kernel stack data. | |
1da177e4 LT |
509 | * due to padding, it's not enough |
510 | * to set all member fields. | |
511 | */ | |
1da177e4 LT |
512 | err = security_msg_queue_msgctl(NULL, cmd); |
513 | if (err) | |
514 | return err; | |
515 | ||
5a06a363 | 516 | memset(&msginfo, 0, sizeof(msginfo)); |
1e786937 KK |
517 | msginfo.msgmni = ns->msg_ctlmni; |
518 | msginfo.msgmax = ns->msg_ctlmax; | |
519 | msginfo.msgmnb = ns->msg_ctlmnb; | |
1da177e4 LT |
520 | msginfo.msgssz = MSGSSZ; |
521 | msginfo.msgseg = MSGSEG; | |
3e148c79 | 522 | down_read(&msg_ids(ns).rw_mutex); |
1da177e4 | 523 | if (cmd == MSG_INFO) { |
1e786937 | 524 | msginfo.msgpool = msg_ids(ns).in_use; |
3ac88a41 KK |
525 | msginfo.msgmap = atomic_read(&ns->msg_hdrs); |
526 | msginfo.msgtql = atomic_read(&ns->msg_bytes); | |
1da177e4 LT |
527 | } else { |
528 | msginfo.msgmap = MSGMAP; | |
529 | msginfo.msgpool = MSGPOOL; | |
530 | msginfo.msgtql = MSGTQL; | |
531 | } | |
7ca7e564 | 532 | max_id = ipc_get_maxid(&msg_ids(ns)); |
3e148c79 | 533 | up_read(&msg_ids(ns).rw_mutex); |
5a06a363 | 534 | if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) |
1da177e4 | 535 | return -EFAULT; |
5a06a363 | 536 | return (max_id < 0) ? 0 : max_id; |
1da177e4 | 537 | } |
2cafed30 DB |
538 | |
539 | case MSG_STAT: | |
1da177e4 LT |
540 | case IPC_STAT: |
541 | { | |
542 | struct msqid64_ds tbuf; | |
543 | int success_return; | |
5a06a363 | 544 | |
1da177e4 LT |
545 | if (!buf) |
546 | return -EFAULT; | |
1da177e4 | 547 | |
ac0ba20e DB |
548 | memset(&tbuf, 0, sizeof(tbuf)); |
549 | ||
550 | rcu_read_lock(); | |
5a06a363 | 551 | if (cmd == MSG_STAT) { |
ac0ba20e DB |
552 | msq = msq_obtain_object(ns, msqid); |
553 | if (IS_ERR(msq)) { | |
554 | err = PTR_ERR(msq); | |
555 | goto out_unlock; | |
556 | } | |
7ca7e564 | 557 | success_return = msq->q_perm.id; |
1da177e4 | 558 | } else { |
ac0ba20e DB |
559 | msq = msq_obtain_object_check(ns, msqid); |
560 | if (IS_ERR(msq)) { | |
561 | err = PTR_ERR(msq); | |
562 | goto out_unlock; | |
563 | } | |
1da177e4 LT |
564 | success_return = 0; |
565 | } | |
ac0ba20e | 566 | |
1da177e4 | 567 | err = -EACCES; |
b0e77598 | 568 | if (ipcperms(ns, &msq->q_perm, S_IRUGO)) |
1da177e4 LT |
569 | goto out_unlock; |
570 | ||
571 | err = security_msg_queue_msgctl(msq, cmd); | |
572 | if (err) | |
573 | goto out_unlock; | |
574 | ||
575 | kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm); | |
576 | tbuf.msg_stime = msq->q_stime; | |
577 | tbuf.msg_rtime = msq->q_rtime; | |
578 | tbuf.msg_ctime = msq->q_ctime; | |
579 | tbuf.msg_cbytes = msq->q_cbytes; | |
580 | tbuf.msg_qnum = msq->q_qnum; | |
581 | tbuf.msg_qbytes = msq->q_qbytes; | |
582 | tbuf.msg_lspid = msq->q_lspid; | |
583 | tbuf.msg_lrpid = msq->q_lrpid; | |
ac0ba20e DB |
584 | rcu_read_unlock(); |
585 | ||
1da177e4 LT |
586 | if (copy_msqid_to_user(buf, &tbuf, version)) |
587 | return -EFAULT; | |
588 | return success_return; | |
589 | } | |
2cafed30 | 590 | |
1da177e4 | 591 | default: |
2cafed30 | 592 | return -EINVAL; |
1da177e4 LT |
593 | } |
594 | ||
2cafed30 | 595 | return err; |
1da177e4 | 596 | out_unlock: |
ac0ba20e | 597 | rcu_read_unlock(); |
1da177e4 LT |
598 | return err; |
599 | } | |
600 | ||
2cafed30 DB |
601 | SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf) |
602 | { | |
603 | int version; | |
604 | struct ipc_namespace *ns; | |
605 | ||
606 | if (msqid < 0 || cmd < 0) | |
607 | return -EINVAL; | |
608 | ||
609 | version = ipc_parse_version(&cmd); | |
610 | ns = current->nsproxy->ipc_ns; | |
611 | ||
612 | switch (cmd) { | |
613 | case IPC_INFO: | |
614 | case MSG_INFO: | |
615 | case MSG_STAT: /* msqid is an index rather than a msg queue id */ | |
616 | case IPC_STAT: | |
617 | return msgctl_nolock(ns, msqid, cmd, version, buf); | |
618 | case IPC_SET: | |
619 | case IPC_RMID: | |
620 | return msgctl_down(ns, msqid, cmd, buf, version); | |
621 | default: | |
622 | return -EINVAL; | |
623 | } | |
624 | } | |
625 | ||
5a06a363 | 626 | static int testmsg(struct msg_msg *msg, long type, int mode) |
1da177e4 LT |
627 | { |
628 | switch(mode) | |
629 | { | |
630 | case SEARCH_ANY: | |
8ac6ed58 | 631 | case SEARCH_NUMBER: |
1da177e4 LT |
632 | return 1; |
633 | case SEARCH_LESSEQUAL: | |
5a06a363 | 634 | if (msg->m_type <=type) |
1da177e4 LT |
635 | return 1; |
636 | break; | |
637 | case SEARCH_EQUAL: | |
5a06a363 | 638 | if (msg->m_type == type) |
1da177e4 LT |
639 | return 1; |
640 | break; | |
641 | case SEARCH_NOTEQUAL: | |
5a06a363 | 642 | if (msg->m_type != type) |
1da177e4 LT |
643 | return 1; |
644 | break; | |
645 | } | |
646 | return 0; | |
647 | } | |
648 | ||
5a06a363 | 649 | static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg) |
1da177e4 | 650 | { |
41239fe8 | 651 | struct msg_receiver *msr, *t; |
5a06a363 | 652 | |
41239fe8 | 653 | list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) { |
5a06a363 IM |
654 | if (testmsg(msg, msr->r_msgtype, msr->r_mode) && |
655 | !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, | |
656 | msr->r_msgtype, msr->r_mode)) { | |
657 | ||
1da177e4 | 658 | list_del(&msr->r_list); |
5a06a363 | 659 | if (msr->r_maxsize < msg->m_ts) { |
1da177e4 LT |
660 | msr->r_msg = NULL; |
661 | wake_up_process(msr->r_tsk); | |
662 | smp_mb(); | |
663 | msr->r_msg = ERR_PTR(-E2BIG); | |
664 | } else { | |
665 | msr->r_msg = NULL; | |
b488893a | 666 | msq->q_lrpid = task_pid_vnr(msr->r_tsk); |
1da177e4 LT |
667 | msq->q_rtime = get_seconds(); |
668 | wake_up_process(msr->r_tsk); | |
669 | smp_mb(); | |
670 | msr->r_msg = msg; | |
5a06a363 | 671 | |
1da177e4 LT |
672 | return 1; |
673 | } | |
674 | } | |
675 | } | |
676 | return 0; | |
677 | } | |
678 | ||
651971cb | 679 | long do_msgsnd(int msqid, long mtype, void __user *mtext, |
680 | size_t msgsz, int msgflg) | |
1da177e4 LT |
681 | { |
682 | struct msg_queue *msq; | |
683 | struct msg_msg *msg; | |
1da177e4 | 684 | int err; |
1e786937 KK |
685 | struct ipc_namespace *ns; |
686 | ||
687 | ns = current->nsproxy->ipc_ns; | |
5a06a363 | 688 | |
1e786937 | 689 | if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0) |
1da177e4 | 690 | return -EINVAL; |
1da177e4 LT |
691 | if (mtype < 1) |
692 | return -EINVAL; | |
693 | ||
651971cb | 694 | msg = load_msg(mtext, msgsz); |
5a06a363 | 695 | if (IS_ERR(msg)) |
1da177e4 LT |
696 | return PTR_ERR(msg); |
697 | ||
698 | msg->m_type = mtype; | |
699 | msg->m_ts = msgsz; | |
700 | ||
3dd1f784 DB |
701 | rcu_read_lock(); |
702 | msq = msq_obtain_object_check(ns, msqid); | |
023a5355 ND |
703 | if (IS_ERR(msq)) { |
704 | err = PTR_ERR(msq); | |
3dd1f784 | 705 | goto out_unlock1; |
023a5355 | 706 | } |
1da177e4 LT |
707 | |
708 | for (;;) { | |
709 | struct msg_sender s; | |
710 | ||
5a06a363 | 711 | err = -EACCES; |
b0e77598 | 712 | if (ipcperms(ns, &msq->q_perm, S_IWUGO)) |
3dd1f784 | 713 | goto out_unlock1; |
1da177e4 LT |
714 | |
715 | err = security_msg_queue_msgsnd(msq, msg, msgflg); | |
716 | if (err) | |
3dd1f784 | 717 | goto out_unlock1; |
1da177e4 | 718 | |
5a06a363 | 719 | if (msgsz + msq->q_cbytes <= msq->q_qbytes && |
1da177e4 LT |
720 | 1 + msq->q_qnum <= msq->q_qbytes) { |
721 | break; | |
722 | } | |
723 | ||
724 | /* queue full, wait: */ | |
5a06a363 IM |
725 | if (msgflg & IPC_NOWAIT) { |
726 | err = -EAGAIN; | |
3dd1f784 | 727 | goto out_unlock1; |
1da177e4 | 728 | } |
3dd1f784 DB |
729 | |
730 | ipc_lock_object(&msq->q_perm); | |
1da177e4 | 731 | ss_add(msq, &s); |
6062a8dc RR |
732 | |
733 | if (!ipc_rcu_getref(msq)) { | |
734 | err = -EIDRM; | |
3dd1f784 | 735 | goto out_unlock0; |
6062a8dc RR |
736 | } |
737 | ||
3dd1f784 DB |
738 | ipc_unlock_object(&msq->q_perm); |
739 | rcu_read_unlock(); | |
1da177e4 LT |
740 | schedule(); |
741 | ||
3dd1f784 DB |
742 | rcu_read_lock(); |
743 | ipc_lock_object(&msq->q_perm); | |
744 | ||
1da177e4 LT |
745 | ipc_rcu_putref(msq); |
746 | if (msq->q_perm.deleted) { | |
747 | err = -EIDRM; | |
3dd1f784 | 748 | goto out_unlock0; |
1da177e4 | 749 | } |
3dd1f784 | 750 | |
1da177e4 | 751 | ss_del(&s); |
5a06a363 | 752 | |
1da177e4 | 753 | if (signal_pending(current)) { |
5a06a363 | 754 | err = -ERESTARTNOHAND; |
3dd1f784 | 755 | goto out_unlock0; |
1da177e4 | 756 | } |
3dd1f784 DB |
757 | |
758 | ipc_unlock_object(&msq->q_perm); | |
1da177e4 LT |
759 | } |
760 | ||
3dd1f784 | 761 | ipc_lock_object(&msq->q_perm); |
b488893a | 762 | msq->q_lspid = task_tgid_vnr(current); |
1da177e4 LT |
763 | msq->q_stime = get_seconds(); |
764 | ||
5a06a363 | 765 | if (!pipelined_send(msq, msg)) { |
25985edc | 766 | /* no one is waiting for this message, enqueue it */ |
5a06a363 | 767 | list_add_tail(&msg->m_list, &msq->q_messages); |
1da177e4 LT |
768 | msq->q_cbytes += msgsz; |
769 | msq->q_qnum++; | |
3ac88a41 KK |
770 | atomic_add(msgsz, &ns->msg_bytes); |
771 | atomic_inc(&ns->msg_hdrs); | |
1da177e4 | 772 | } |
5a06a363 | 773 | |
1da177e4 LT |
774 | err = 0; |
775 | msg = NULL; | |
776 | ||
3dd1f784 DB |
777 | out_unlock0: |
778 | ipc_unlock_object(&msq->q_perm); | |
779 | out_unlock1: | |
780 | rcu_read_unlock(); | |
5a06a363 | 781 | if (msg != NULL) |
1da177e4 LT |
782 | free_msg(msg); |
783 | return err; | |
784 | } | |
785 | ||
e48fbb69 HC |
786 | SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, |
787 | int, msgflg) | |
651971cb | 788 | { |
789 | long mtype; | |
790 | ||
791 | if (get_user(mtype, &msgp->mtype)) | |
792 | return -EFAULT; | |
793 | return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg); | |
794 | } | |
795 | ||
5a06a363 | 796 | static inline int convert_mode(long *msgtyp, int msgflg) |
1da177e4 | 797 | { |
8ac6ed58 PH |
798 | if (msgflg & MSG_COPY) |
799 | return SEARCH_NUMBER; | |
5a06a363 | 800 | /* |
1da177e4 LT |
801 | * find message of correct type. |
802 | * msgtyp = 0 => get first. | |
803 | * msgtyp > 0 => get first message of matching type. | |
5a06a363 | 804 | * msgtyp < 0 => get message with least type must be < abs(msgtype). |
1da177e4 | 805 | */ |
5a06a363 | 806 | if (*msgtyp == 0) |
1da177e4 | 807 | return SEARCH_ANY; |
5a06a363 IM |
808 | if (*msgtyp < 0) { |
809 | *msgtyp = -*msgtyp; | |
1da177e4 LT |
810 | return SEARCH_LESSEQUAL; |
811 | } | |
5a06a363 | 812 | if (msgflg & MSG_EXCEPT) |
1da177e4 LT |
813 | return SEARCH_NOTEQUAL; |
814 | return SEARCH_EQUAL; | |
815 | } | |
816 | ||
f9dd87f4 SK |
817 | static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz) |
818 | { | |
819 | struct msgbuf __user *msgp = dest; | |
820 | size_t msgsz; | |
821 | ||
822 | if (put_user(msg->m_type, &msgp->mtype)) | |
823 | return -EFAULT; | |
824 | ||
825 | msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz; | |
826 | if (store_msg(msgp->mtext, msg, msgsz)) | |
827 | return -EFAULT; | |
828 | return msgsz; | |
829 | } | |
830 | ||
4a674f34 | 831 | #ifdef CONFIG_CHECKPOINT_RESTORE |
3fcfe786 SK |
832 | /* |
833 | * This function creates new kernel message structure, large enough to store | |
834 | * bufsz message bytes. | |
835 | */ | |
8ac6ed58 | 836 | static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) |
4a674f34 SK |
837 | { |
838 | struct msg_msg *copy; | |
839 | ||
4a674f34 SK |
840 | /* |
841 | * Create dummy message to copy real message to. | |
842 | */ | |
843 | copy = load_msg(buf, bufsz); | |
844 | if (!IS_ERR(copy)) | |
845 | copy->m_ts = bufsz; | |
846 | return copy; | |
847 | } | |
848 | ||
85398aa8 | 849 | static inline void free_copy(struct msg_msg *copy) |
4a674f34 | 850 | { |
85398aa8 | 851 | if (copy) |
4a674f34 SK |
852 | free_msg(copy); |
853 | } | |
854 | #else | |
8ac6ed58 | 855 | static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz) |
b30efe27 SK |
856 | { |
857 | return ERR_PTR(-ENOSYS); | |
858 | } | |
859 | ||
85398aa8 SK |
860 | static inline void free_copy(struct msg_msg *copy) |
861 | { | |
862 | } | |
4a674f34 SK |
863 | #endif |
864 | ||
daaf74cf PH |
865 | static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode) |
866 | { | |
867 | struct msg_msg *msg; | |
868 | long count = 0; | |
869 | ||
870 | list_for_each_entry(msg, &msq->q_messages, m_list) { | |
871 | if (testmsg(msg, *msgtyp, mode) && | |
872 | !security_msg_queue_msgrcv(msq, msg, current, | |
873 | *msgtyp, mode)) { | |
874 | if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) { | |
875 | *msgtyp = msg->m_type - 1; | |
876 | } else if (mode == SEARCH_NUMBER) { | |
877 | if (*msgtyp == count) | |
878 | return msg; | |
879 | } else | |
880 | return msg; | |
881 | count++; | |
882 | } | |
883 | } | |
884 | ||
885 | return ERR_PTR(-EAGAIN); | |
886 | } | |
887 | ||
888 | ||
f9dd87f4 SK |
889 | long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, |
890 | int msgflg, | |
891 | long (*msg_handler)(void __user *, struct msg_msg *, size_t)) | |
1da177e4 LT |
892 | { |
893 | struct msg_queue *msq; | |
894 | struct msg_msg *msg; | |
895 | int mode; | |
1e786937 | 896 | struct ipc_namespace *ns; |
85398aa8 | 897 | struct msg_msg *copy = NULL; |
1da177e4 | 898 | |
88b9e456 PH |
899 | ns = current->nsproxy->ipc_ns; |
900 | ||
f9dd87f4 | 901 | if (msqid < 0 || (long) bufsz < 0) |
1da177e4 | 902 | return -EINVAL; |
4a674f34 | 903 | if (msgflg & MSG_COPY) { |
8ac6ed58 | 904 | copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); |
4a674f34 SK |
905 | if (IS_ERR(copy)) |
906 | return PTR_ERR(copy); | |
907 | } | |
5a06a363 | 908 | mode = convert_mode(&msgtyp, msgflg); |
1da177e4 | 909 | |
023a5355 | 910 | msq = msg_lock_check(ns, msqid); |
4a674f34 | 911 | if (IS_ERR(msq)) { |
85398aa8 | 912 | free_copy(copy); |
023a5355 | 913 | return PTR_ERR(msq); |
4a674f34 | 914 | } |
1da177e4 LT |
915 | |
916 | for (;;) { | |
917 | struct msg_receiver msr_d; | |
1da177e4 LT |
918 | |
919 | msg = ERR_PTR(-EACCES); | |
b0e77598 | 920 | if (ipcperms(ns, &msq->q_perm, S_IRUGO)) |
1da177e4 LT |
921 | goto out_unlock; |
922 | ||
daaf74cf PH |
923 | msg = find_msg(msq, &msgtyp, mode); |
924 | ||
5a06a363 IM |
925 | if (!IS_ERR(msg)) { |
926 | /* | |
927 | * Found a suitable message. | |
928 | * Unlink it from the queue. | |
929 | */ | |
f9dd87f4 | 930 | if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { |
1da177e4 LT |
931 | msg = ERR_PTR(-E2BIG); |
932 | goto out_unlock; | |
933 | } | |
3fcfe786 SK |
934 | /* |
935 | * If we are copying, then do not unlink message and do | |
936 | * not update queue parameters. | |
937 | */ | |
852028af PH |
938 | if (msgflg & MSG_COPY) { |
939 | msg = copy_msg(msg, copy); | |
4a674f34 | 940 | goto out_unlock; |
852028af | 941 | } |
1da177e4 LT |
942 | list_del(&msg->m_list); |
943 | msq->q_qnum--; | |
944 | msq->q_rtime = get_seconds(); | |
b488893a | 945 | msq->q_lrpid = task_tgid_vnr(current); |
1da177e4 | 946 | msq->q_cbytes -= msg->m_ts; |
3ac88a41 KK |
947 | atomic_sub(msg->m_ts, &ns->msg_bytes); |
948 | atomic_dec(&ns->msg_hdrs); | |
5a06a363 | 949 | ss_wakeup(&msq->q_senders, 0); |
1da177e4 LT |
950 | msg_unlock(msq); |
951 | break; | |
952 | } | |
953 | /* No message waiting. Wait for a message */ | |
954 | if (msgflg & IPC_NOWAIT) { | |
955 | msg = ERR_PTR(-ENOMSG); | |
956 | goto out_unlock; | |
957 | } | |
5a06a363 | 958 | list_add_tail(&msr_d.r_list, &msq->q_receivers); |
1da177e4 LT |
959 | msr_d.r_tsk = current; |
960 | msr_d.r_msgtype = msgtyp; | |
961 | msr_d.r_mode = mode; | |
5a06a363 | 962 | if (msgflg & MSG_NOERROR) |
1da177e4 | 963 | msr_d.r_maxsize = INT_MAX; |
5a06a363 | 964 | else |
f9dd87f4 | 965 | msr_d.r_maxsize = bufsz; |
1da177e4 LT |
966 | msr_d.r_msg = ERR_PTR(-EAGAIN); |
967 | current->state = TASK_INTERRUPTIBLE; | |
968 | msg_unlock(msq); | |
969 | ||
970 | schedule(); | |
971 | ||
972 | /* Lockless receive, part 1: | |
973 | * Disable preemption. We don't hold a reference to the queue | |
974 | * and getting a reference would defeat the idea of a lockless | |
975 | * operation, thus the code relies on rcu to guarantee the | |
25985edc | 976 | * existence of msq: |
1da177e4 LT |
977 | * Prior to destruction, expunge_all(-EIRDM) changes r_msg. |
978 | * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. | |
979 | * rcu_read_lock() prevents preemption between reading r_msg | |
980 | * and the spin_lock() inside ipc_lock_by_ptr(). | |
981 | */ | |
982 | rcu_read_lock(); | |
983 | ||
984 | /* Lockless receive, part 2: | |
985 | * Wait until pipelined_send or expunge_all are outside of | |
986 | * wake_up_process(). There is a race with exit(), see | |
987 | * ipc/mqueue.c for the details. | |
988 | */ | |
5a06a363 | 989 | msg = (struct msg_msg*)msr_d.r_msg; |
1da177e4 LT |
990 | while (msg == NULL) { |
991 | cpu_relax(); | |
5a06a363 | 992 | msg = (struct msg_msg *)msr_d.r_msg; |
1da177e4 LT |
993 | } |
994 | ||
995 | /* Lockless receive, part 3: | |
996 | * If there is a message or an error then accept it without | |
997 | * locking. | |
998 | */ | |
5a06a363 | 999 | if (msg != ERR_PTR(-EAGAIN)) { |
1da177e4 LT |
1000 | rcu_read_unlock(); |
1001 | break; | |
1002 | } | |
1003 | ||
1004 | /* Lockless receive, part 3: | |
1005 | * Acquire the queue spinlock. | |
1006 | */ | |
1007 | ipc_lock_by_ptr(&msq->q_perm); | |
1008 | rcu_read_unlock(); | |
1009 | ||
1010 | /* Lockless receive, part 4: | |
1011 | * Repeat test after acquiring the spinlock. | |
1012 | */ | |
1013 | msg = (struct msg_msg*)msr_d.r_msg; | |
5a06a363 | 1014 | if (msg != ERR_PTR(-EAGAIN)) |
1da177e4 LT |
1015 | goto out_unlock; |
1016 | ||
1017 | list_del(&msr_d.r_list); | |
1018 | if (signal_pending(current)) { | |
1019 | msg = ERR_PTR(-ERESTARTNOHAND); | |
1020 | out_unlock: | |
1021 | msg_unlock(msq); | |
1022 | break; | |
1023 | } | |
1024 | } | |
4a674f34 | 1025 | if (IS_ERR(msg)) { |
85398aa8 | 1026 | free_copy(copy); |
5a06a363 | 1027 | return PTR_ERR(msg); |
4a674f34 | 1028 | } |
1da177e4 | 1029 | |
f9dd87f4 | 1030 | bufsz = msg_handler(buf, msg, bufsz); |
1da177e4 | 1031 | free_msg(msg); |
5a06a363 | 1032 | |
f9dd87f4 | 1033 | return bufsz; |
1da177e4 LT |
1034 | } |
1035 | ||
e48fbb69 HC |
1036 | SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz, |
1037 | long, msgtyp, int, msgflg) | |
651971cb | 1038 | { |
f9dd87f4 | 1039 | return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill); |
651971cb | 1040 | } |
1041 | ||
1da177e4 | 1042 | #ifdef CONFIG_PROC_FS |
19b4946c | 1043 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it) |
1da177e4 | 1044 | { |
1efdb69b | 1045 | struct user_namespace *user_ns = seq_user_ns(s); |
19b4946c MW |
1046 | struct msg_queue *msq = it; |
1047 | ||
1048 | return seq_printf(s, | |
5a06a363 IM |
1049 | "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n", |
1050 | msq->q_perm.key, | |
7ca7e564 | 1051 | msq->q_perm.id, |
5a06a363 IM |
1052 | msq->q_perm.mode, |
1053 | msq->q_cbytes, | |
1054 | msq->q_qnum, | |
1055 | msq->q_lspid, | |
1056 | msq->q_lrpid, | |
1efdb69b EB |
1057 | from_kuid_munged(user_ns, msq->q_perm.uid), |
1058 | from_kgid_munged(user_ns, msq->q_perm.gid), | |
1059 | from_kuid_munged(user_ns, msq->q_perm.cuid), | |
1060 | from_kgid_munged(user_ns, msq->q_perm.cgid), | |
5a06a363 IM |
1061 | msq->q_stime, |
1062 | msq->q_rtime, | |
1063 | msq->q_ctime); | |
1da177e4 LT |
1064 | } |
1065 | #endif |